Beauty Tech, Inc

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465 Golden Beach Dr

North Miami, Florida 33160

United States of America

http://www.beautytec.com/

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We offer the highest quality in Professional Aesthetic Skin Care Equipment and In-Home Beauty Treatment Equipment currently in the market. We pride ourselves on the best prices and customer service in the industry. Our design team is constantly working to improve and incorporate innovative functions for your convenience and to accommodate the ever changing trends of the market for spas, beauty schools, estheticians and home users. All our products are manufactured and serviced in the USA by Beauty Tech, Inc. We provide our clients a three years limited warranty in parts and labor.

Our mission is to be our customer’s first choice supplier, offer the latest home beauty equipment products including warranty and to service those orders efficiently and economically to our customers’ complete satisfaction.

Today, our strengths are design skills – innovation and revelation, creativity, product functionality, far East sourcing skills - long term relationships, quality assurance ,stock and service commitment - own warehousing, innovative range of product categories – home and professional beauty equipment, high quality products with great service and warranties, financial stability and resources, affordable pricing and product customization

Please take a moment to navigate into our website. We look forward to having you join our customer base of Beauty Tech Inc.

Esthetics Equipment

Portable Microdermabrasion Machine

Limited time sale - Elite 2000 Diamond tips with Led light red / blue Only $1000

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Coupon Code MACHINE02 Expiration Date 04/30/2011
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Single & Multifunctional Facial Machines

Microdermabrasion Machines

On the purchase of any Microdermabrasion machine, receive free shipping in continental U.S.A

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U.S.A Only Must mention this coupon for free shipping.

Coupon Code MACHINE01 Expiration Date 07/31/2011
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These products are great! The service was exceptional and they take great care over ensuring I am ordering the right product for my needs. I'm happy!

—Sally F

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Oxygen Equipment, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Oxygen Equipment

# 5 Liter Oxygen concentrator # Single phase # Max. flow rates: 5 LPM # Use no oil or grease # 115 VAC # 60 HZ # 4.2 AMP # 400 W Avg # Double Insulated # CAN/CSA/UL/FDA approved # Accessories Includes (Disp. Mask, Disp. Nose tubing, Two sprayers face & body and Oxygen Activator ) # Oxygen Concentration at 22 MP: 93 % +- 3%

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Therapy Light, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Therapy Light

mini color therapy light

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Fusion Glow Gun, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Fusion Glow Gun

What it is formulated to do: The first and only at-home and fully rechargeable airbrush gun blows out a sheer, vapor-light, even mist in an all new, cocoa-infused GlowFusion Micro-Nutrient Tinted Protein Tan Mist that dries on contact. No need to smooth, spread, or touch. The AirGlow Kit contains: one AirGlow™ Airbrush gun; 4 oz Micro-Nutrient Tinted Protein Tan Mist with new, all natural, cocoa-infused micro-nutrient tinted formula for an instantly glowing seamless application; AC adapter and charging connector; and funnel for simple transfer into the airbrush gun cartridge. Warranty included.

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Vibra Light, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Vibra Light

Feature： Battery operated：4.5V (AAA x 3pcs) Vibration massage (1200 gauss±200 gauss) Infrared light Electronic Toning Switch Position: 0. Off 1. Vibrationboutzina@hotmail.com II. Vibration +Infrared light Specifications: Input: DC 4.5V Current: Electronic Toning: 5.3mA±0.5mA (No LOAD) Vibration: 70mA±10mA Vibration + Infrared: 110mA±20mA Output: 20V±2V (10K loading) Frequency: 12HZ±2HZ Bandwidth: 3.0ms~3.5ms Output max: 50V±2V

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Face Roller, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Face Roller

Vibratory Beautification Massager-Features: 1. Smooth face wrinkles 2. Eliminate black eye sockets 3. Eliminate eye strain 4. Improve blood circulation 5. Improve metabolism 6. Eliminate dust in the pores, restrain formation of melanin 7. Burn hypodermal fat, slim the face 8. Increase skin’s resistibility to bacteria 9. 6 massage modes (3 basic modes and 3 combined modes) 10. Automatic 20-minute shut down Note: The normal color of product is pearl white, other colors are customized in advance. Vibratory Beautification Massager-Specification Model: Y-B1806 Name: Vibratory Beautification Massager box size(cm): 8.9X4.1X21.4 carton size(cm): 46.2X43X44.5 pcs/carton: 100 G.W(Kg): 13.42 N.W(kg): 12.24

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Eye Roller, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Eye Roller

Product Function: 1. Eliminate the black eye rim,pouch and wrinkles effectively. 2. Smooth the skin around the eyes and restore the elasticity. 3. Fade the splash and shrik pore. 4. Comfort eye fatigue. Product Features: 1. Conduct heat by far-infrared technology,with silicone material containing hairdressing mineral element. 2. Exquisite and fashionable appearance. 3. Portable and easy to use. Eye Roller-Specification Model: Y-B1809 Name: Eye Roller unit size(cm): 18x2.5x2.5 box size(cm): 21x16x6 carton size(cm): 49X43.4X36.3 pcs/carton: 36 G.W(Kg): 14.5 N.W(kg): 13.5 Eye Roller-Certificate ATC: ATE2004487 Patent: ZL200420014715.4

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Skin Analyzer, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Skin Analyzer

BIA Skin Analyzer-Features: 1. Display moisture content 2. Display oil content 3. Display softness level 4. Backlight LCD 5. Display results in 6 seconds 6. Refined appearance, easy to use The latest Bioelectric Impedance Analysis (BIA) technology immediately and automatically detects the skin conditions, such as moisture, oil, softness and displays the result on LCD screen with convenient graphical illustration and description. BIA Skin Analyzer-Specification Model: Y-B2006 Name: BIA Skin Analyzer unit size (cm): 13.5x3.5x2.5 box size(cm): 17.2x9x4.5 carton size(cm): 43x34.5x38.5 pcs/carton: 60 G.W(Kg): 6.2 N.W(kg): 5.6

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Ultrasonic Massager, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Ultrasonic Massager

Model No: SR-06A Utilizing 5Mhz, special frequency for delicate FACIAL skin layer. Normally 1Mhz enters into skin around 3-5cm while 5Mhz enters only around 5mm, more safe for thin face skin. The ultrasonic fine vibrations help to accelerate the metabolism of your skin, revive the cells in the tissues, and eliminate waste from skin. Also helps skin absorb nutrition. * Very high frequency, 5Mhz, specially for delicate face skin. * Helps to reduce discoloration after acne break-outs. * Diminishes puffiness and dark circles under the eyes. * Dissolves melanin and eliminates black pigmentation. * Skin firming. * Reduce fine lines and wrinkles. * Enhances tissue oxygenation. Specifications: 1. Waterproof 2. Frequency: 5Mhz, 5 million stimulations to skin per second 3. Cordless with built-in rechargeable battery 4. 2-hour fast charging 5. Material: ABS 6. Unit dimension: 48 x 44 x 166 mm 7. Unit weight: 180 g 8. Charging adaptor: universal type, fit for 100-240V, 50-60Hz

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Eyebrow Trimmer of LED, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Eyebrow Trimmer of LED

* With SUPER bright LED illuminating for usage in gloomy areas, like bathroom, car, etc. * Remove tiny hair on face, neck or arm. * Remove or trim eyebrow to specified length. * Miny design, easy for carrying & storage in handbag. * Luxury pearl white painting Specifications: 1. Stainless blade 2. Rounded blade tip, will not hurt skin 3. Material : ABS 4. Unit Dimension : 20 x 20 x 148 mm 5. Unit Weight: 23 g 6. Power: 1.5V, 1pc AM battery, excluded 7. Accessories: Short Eyebrow Trimmer, Long Eyebrow Trimmer, Cleaning Brush

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Nose Trimmer, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Nose Trimmer

* With SUPER bright LED illuminating for usage in gloomy areas, like bathroom, car; etc. * Remove tiny hair in NOSE. * Remove tiny hair in EAR. * Mini design, easy for carrying & storage in handbag. * Luxury pearl white painting. Specifications: 1. Stainless blade 2. Rounded blade tip, will not hurt skin 3. Material: ABS 4. Unit Dimension : 20 x 20 x 148 mm 5. Unit Weight : 23 g 6. Power: 1.5V, 1 pc AAA battery, excluded 7. Accessories : Cleaning Brush

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Pimple Remover, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Pimple Remover

Model No.: SR-09A Hand-held battery-operated device which makes pimple disappear fast. Utilizing two technologies, gentle, natural heat and a specified blue wavelength, the most advanced beauty technology for pimple treatment. Designed to treat mild & moderate inflammatory acne, useful both for young people & adults. When the biocompatible tip has a direct contact with a blemish on the skin, it will transfer heat into the follicle with a pre-set temperature and generate blue light with specified wave length. Both heat-shock response and blue light will shock proteins, activated by bacterial cells, causing the self-destruction of acnes within the lesion, reducing inflammation and allowing the skin to return to a healthy condition. Specifications: 1. Temperature: 45 degrees C 2. Blue wavelength: 415nm 3. Main case: ABS 4. Unit dimension: 155 x 26 x 20 mm 5. Unit weight: 75 g 6. Main case: ABS for main unit 7. Power: 1.5V, 1pc AA battery, included

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Facial Brush Massager, design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Facial Brush Massager

Model No.: SR-03 Streamline design. Small and portable for usage. Compact accessories for various usage. * Deeply clean facial & body skin * Exfoliation of dead cell * Reducing & erasing fine pimples & blackheads * Removing hard cells under foot & elbow * Taking care of nails Specifications: 1. Material: ABS 2. Unit dimension: 130 x 45 x 68 mm 3. Unit weight: 78.8 g 4. Power: 3V, 2pcs AA batteries, excluded 5. Accessories: facial brush (1pc); facial sponge (1pc); nail buffer (1pc); pumice (1pc)

Tag: design, microdermabrasion, devices, cosmetic, anti aging, acne, professional, beauty, wholesale, cosmetology

Buzzwords

  • skin Return to the top
  • Skin is a soft outer covering of an animal, in particular a vertebrate. Other animal coverings such as the arthropod exoskeleton or the seashell have different developmental origin, structure and chemical composition. The adjective cutaneous literally means "of the skin" (from Latin cutis, skin). In mammals, the skin is the largest organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs.[1] Skin of a different nature exists in amphibians, reptiles, and birds.[2] All mammals have some hair on their skin, even marine mammals which appear to be hairless. Because it interfaces with the environment, skin plays a key role in protecting (the body) against pathogens[3] and excessive water loss.[4] Its other functions are insulation, temperature regulation, sensation, and the protection of vitamin B folates. Severely damaged skin will try to heal by forming scar tissue. This is often discoloured and depigmented. Hair with sufficient density is called fur. The fur mainly serves to augment the insulation the skin provides, but can also serve as a secondary sexual characteristic or as camouflage. On some animals, the skin is very hard and thick, and can be processed to create leather. Reptiles and fish have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough β-keratins. Amphibian skin is not a strong barrier to passage of chemicals and is often subject to osmosis. A frog sitting in an anesthetic solution could quickly go to sleep. A close up picture of layers of human skin. Contents [hide] * 1 Functions * 2 Mammalian skin layers o 2.1 Epidermis + 2.1.1 Layers + 2.1.2 Sublayers o 2.2 Dermis + 2.2.1 Papillary region + 2.2.2 Reticular region o 2.3 Hypodermis * 3 In fish and amphibians * 4 In birds and reptiles * 5 Mechanics * 6 Human uses and culture * 7 See also * 8 References [edit] Functions Skin performs the following functions: 1. Protection: an anatomical barrier from pathogens and damage between the internal and external environment in bodily defense; Langerhans cells in the skin are part of the adaptive immune system.[3][4] 2. Sensation: contains a variety of nerve endings that jump to heat and cold, touch, pressure, vibration, and tissue injury; see somatosensory system and haptic perception. 3. Heat regulation: increase perfusion and heatloss, while constricted vessels greatly reduce cutaneous blood flow and conserve heat. Erector pili muscles are significant in animals. 4. Control of evaporation: the skin provides a relatively dry and semi-impermeable barrier to fluid loss.[4] 5. Storage and synthesis: acts as a storage center for lipids and water 6. Absorption: Oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in small amounts, some animals uses their skin for their sole respiration organ (contrary to popular belief, however, humans do not absorb oxygen through the skin).[5] 7. Water resistance: The skin acts as a water resistant barrier so essential nutrients aren't washed out of the body. [edit] Mammalian skin layers Mammalian skin is composed of two primary layers: * the epidermis, which provides waterproofing and serves as a barrier to infection; and * the dermis, which serves as a location for the appendages of skin; [edit] Epidermis Epidermis, "epi" coming from the Greek meaning "over" or "upon", is the outermost layer of the skin. It forms the waterproof, protective wrap over the body's surface and is made up of stratified squamous epithelium with an underlying basal lamina. The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. The main type of cells which make up the epidermis are Merkel cells, keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strata (beginning with the outermost layer): corneum, lucidum (only in palms of hands and bottoms of feet), granulosum, spinosum, basale. Cells are formed through mitosis at the basale layer. The daughter cells (see cell division) move up the strata changing shape and composition as they die due to isolation from their blood source. The cytoplasm is released and the protein keratin is inserted. They eveantually reach the corneum and slough off (desquamation). This process is called keratinization and takes place within about 27 days. This keratinized layer of skin is responsible for keeping water in the body and keeping other harmful chemicals and pathogens out, making skin a natural barrier to infection. The epidermis helps the skin to regulate body temperature. [also see: image rotating (1.1 mb) ] Optical coherence tomogram of fingertip, depicting stratum corneum (~500 µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. At the bottom superficial parts of the dermis. Sweatducts are clearly visible. [edit] Layers The epidermis is divided into several layers where cells are formed through mitosis at the innermost layers. They move up the strata, changing shape and composition as they differentiate and become filled with keratin. They eventually reach the top layer, called the stratum corneum, consisting of approximately 15-350 layers of dead cells strengthened and made water-resistant by the keratin. This process is called keratinization. The dead cells are then sloughed off, or desquamated, which takes place within weeks. [edit] Sublayers Epidermis is divided into the following 5 sublayers or strata: * Stratum corneum * Stratum lucidum * Stratum granulosum * Stratum spinosum * Stratum germinativum (also called the"stratum basale") Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. Arterial shunt vessels may bypass the network in ears, the nose and fingertips. Dermis Gray942.png The distribution of the bloodvessels in the skin of the sole of the foot. (Corium - TA alternate term for dermis - is labeled at upper right.) Gray940.png A diagrammatic sectional view of the skin (click on image to magnify). (Dermis labeled at center right.) Gray's subject #234 1065 MeSH Dermis Dorlands/Elsevier Skin [edit] Dermis The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors (nerve endings) that provide the sense of touch and heat. It contains the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood vessels. The blood vessels in the dermis provide nourishment and waste removal from its own cells as well as from the Stratum basale of the epidermis. The dermis is structurally divided into two areas: a superficial area adjacent to the epidermis, called the papillary region, and a deep thicker area known as the reticular region. [edit] Papillary region The papillary region is composed of loose areolar connective tissue. This is named for its fingerlike projections called papillae, that extend toward the epidermis. The papillae provide the dermis with a "bumpy" surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin. [edit] Reticular region The reticular region lies deep in the papillary region and is usually much thicker. It is composed of dense irregular connective tissue, and receives its name from the dense concentration of collagenous, elastic, and reticular fibres that weave throughout it. These protein fibres give the dermis its properties of strength, extensibility, and elasticity. Also located within the reticular region are the roots of the hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels. [edit] Hypodermis The hypodermis is not part of the skin, and lies below the dermis. Its purpose is to attach the skin to underlying bone and muscle as well as supplying it with blood vessels and nerves. It consists of loose connective tissue and elastin. The main cell types are fibroblasts, macrophages and adipocytes (the hypodermis contains 50% of body fat). Fat serves as padding and insulation for the body. Another name for the hypodermis is the subcutaneous tissue. Microorganisms like Staphylococcus epidermidis colonize the skin surface. The density of skin flora depends on region of the skin. The disinfected skin surface gets recolonized from bacteria residing in the deeper areas of the hair follicle, gut and urogenital openings. [edit] In fish and amphibians The epidermis of fish and of most amphibians consists entirely of live cells, with only minimal quantities of keratin in the cells of the superficial layer. It is generally permeable, and, in the case of many amphibians, may actually be a major respiratory organ. The dermis of bony fish typically contains relatively little of the connective tissue found in tetrapods. Instead, in most species, it is largely replaced by solid, protective bony scales. Apart from some particularly large dermal bones that form parts of the skull, these scales are lost in tetrapods, although many reptiles do have scales of a different kind, as do pangolins. Cartilaginous fish have numerous tooth-like denticles embedded in their skin, in place of true scales. Sweat glands and sebaceous glands are both unique to mammals, but other types of skin gland are found in other vertebrates. Fish typically have a numerous individual mucus-secreting skin cells that aid in insulation and protection, but may also have poison glands, photophores, or cells that produce a more watery, serous fluid. In amphibians, the mucus cells are gathered together to form sac-like glands. Most living amphibians also possess granular glands in the skin, that secrete irritating or toxic compounds.[6] Although melanin is found in the skin of many species, in reptiles, amphibians, and fish, the epidermis is often relatively colourless. Instead, the colour of the skin is largely due to chromatophores in the dermis, which, in addition to melanin, may contain guanine or carotenoid pigments. Many species, such as chameleons and flounders may be able to change the colour of their skin by adjusting the relative size of their chromatophores.[6] [edit] In birds and reptiles Main article: Reptile scales The epidermis of birds and reptiles is closer to that of mammals, with a layer of dead keratin-filled cells at the surface, to help reduce water loss. A similar pattern is also seen in some of the more terrestrial amphibians, such as toads. However, in all of these animals there is no clear differentiation of the epidermis into distinct layers, as occurs in humans, with the change in cell type being relatively gradual. The mammalian epidermis always possesses at least a stratum germinativum and stratum corneum, but the other intermediate layers found in humans are not always distinguishable. Hair is a distinctive feature of mammalian skin, while feathers are (at least among living species) similarly unique to birds.[6] Birds and reptiles have relatively few skin glands, although there may be a few structures for specific purposes, such as pheromone-secreting cells in some reptiles, or the uropygial gland of most birds.[6] [edit] Mechanics Main article: Soft tissue Skin has a soft tissue mechanical behavior when stretched. The intact skin is prestreched (i.e. has residual stress) like neoprene wetsuits around the diver's body. When deep cuts are made on the skin, it retracts, widening the slice hole. [edit] Human uses and culture The term "skin" may also refer to the covering of a small animal, such as a sheep, goat (goatskin), pig, snake (snakeskin) etc. or the young of a large animal. The term hides or rawhide refers to the covering of a large adult animal such as a cow, buffalo, horse etc. Skins and hides from different animals are used for clothing, bags and other consumer products, usually in the form of leather, but also furs. Skin can also be cooked to make pork rind or crackling.
  • engineered Return to the top
  • Engineering From Wikipedia, the free encyclopedia (Redirected from Engineered) Jump to: navigation, search The Watt steam engine, a major driver in the Industrial Revolution, underscores the importance of engineering in modern history. This model is on display at the main building of the ETSIIM in Madrid, Spain Engineering is the discipline, art, and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of people. The American Engineers' Council for Professional Development (ECPD, the predecessor of ABET)[1] has defined "engineering" as: [T]he creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property.[2][3][4] One who practices engineering is called an engineer, and those licensed to do so may have more formal designations such as Professional Engineer, Chartered Engineer, Incorporated Engineer, Ingenieur or European Engineer. The broad discipline of engineering encompasses a range of more specialized subdisciplines, each with a more specific emphasis on certain fields of application and particular areas of technology. Contents [hide] * 1 History o 1.1 Ancient era o 1.2 Renaissance era o 1.3 Modern era * 2 Main branches of engineering * 3 Methodology o 3.1 Problem solving o 3.2 Computer use * 4 Social context * 5 Relationships with other disciplines o 5.1 Science o 5.2 Medicine and biology o 5.3 Art o 5.4 Other fields * 6 See also * 7 References * 8 Further reading * 9 External links [edit] History Look up engineering in Wiktionary, the free dictionary. The concept of engineering has existed since ancient times as humans devised fundamental inventions such as the pulley, lever, and wheel. Each of these inventions is consistent with the modern definition of engineering, exploiting basic mechanical principles to develop useful tools and objects. The term engineering itself has a much more recent etymology, deriving from the word engineer, which itself dates back to 1325, when an engine’er (literally, one who operates an engine) originally referred to “a constructor of military engines.”[5] In this context, now obsolete, an “engine” referred to a military machine, i.e., a mechanical contraption used in war (for example, a catapult). Notable exceptions of the obsolete usage which have survived to the present day are military engineering corps, e.g., the U.S. Army Corps of Engineers. The word “engine” itself is of even older origin, ultimately deriving from the Latin ingenium (c. 1250), meaning “innate quality, especially mental power, hence a clever invention.”[6] Later, as the design of civilian structures such as bridges and buildings matured as a technical discipline, the term civil engineering[4] entered the lexicon as a way to distinguish between those specializing in the construction of such non-military projects and those involved in the older discipline of military engineering. [edit] Ancient era The Pharos of Alexandria, the pyramids in Egypt, the Hanging Gardens of Babylon, the Acropolis and the Parthenon in Greece, the Roman aqueducts, Via Appia and the Colosseum, Teotihuacán and the cities and pyramids of the Mayan, Inca and Aztec Empires, the Great Wall of China, among many others, stand as a testament to the ingenuity and skill of the ancient civil and military engineers. The earliest civil engineer known by name is Imhotep.[4] As one of the officials of the Pharaoh, Djosèr, he probably designed and supervised the construction of the Pyramid of Djoser (the Step Pyramid) at Saqqara in Egypt around 2630-2611 BC.[7] He may also have been responsible for the first known use of columns in architecture[citation needed]. Ancient Greece developed machines in both the civilian and military domains. The Antikythera mechanism, the first known mechanical computer,[8][9] and the mechanical inventions of Archimedes are examples of early mechanical engineering. Some of Archimedes' inventions as well as the Antikythera mechanism required sophisticated knowledge of differential gearing or epicyclic gearing, two key principles in machine theory that helped design the gear trains of the Industrial revolution, and are still widely used today in diverse fields such as robotics and automotive engineering.[10] Chinese, Greek and Roman armies employed complex military machines and inventions such as artillery which was developed by the Greeks around the 4th century B.C.,[11] the trireme, the ballista and the catapult. In the Middle Ages, the Trebuchet was developed. [edit] Renaissance era The first electrical engineer is considered to be William Gilbert, with his 1600 publication of De Magnete, who was the originator of the term "electricity".[12] The first steam engine was built in 1698 by mechanical engineer Thomas Savery.[13] The development of this device gave rise to the industrial revolution in the coming decades, allowing for the beginnings of mass production. With the rise of engineering as a profession in the eighteenth century, the term became more narrowly applied to fields in which mathematics and science were applied to these ends. Similarly, in addition to military and civil engineering the fields then known as the mechanic arts became incorporated into engineering. [edit] Modern era The International Space Station represents a modern engineering challenge from many disciplines. Electrical engineering can trace its origins in the experiments of Alessandro Volta in the 1800s, the experiments of Michael Faraday, Georg Ohm and others and the invention of the electric motor in 1872. The work of James Maxwell and Heinrich Hertz in the late 19th century gave rise to the field of Electronics. The later inventions of the vacuum tube and the transistor further accelerated the development of electronics to such an extent that electrical and electronics engineers currently outnumber their colleagues of any other Engineering specialty.[4] The inventions of Thomas Savery and the Scottish engineer James Watt gave rise to modern Mechanical Engineering. The development of specialized machines and their maintenance tools during the industrial revolution led to the rapid growth of Mechanical Engineering both in its birthplace Britain and abroad.[4] Chemical Engineering, like its counterpart Mechanical Engineering, developed in the nineteenth century during the Industrial Revolution.[4] Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants.[4] The role of the chemical engineer was the design of these chemical plants and processes.[4] Aeronautical Engineering deals with aircraft design while Aerospace Engineering is a more modern term that expands the reach envelope of the discipline by including spacecraft design.[14] Its origins can be traced back to the aviation pioneers around the turn of the century from the 19th century to the 20th although the work of Sir George Cayley has recently been dated as being from the last decade of the 18th century. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering.[15] The first PhD in engineering (technically, applied science and engineering) awarded in the United States went to Willard Gibbs at Yale University in 1863; it was also the second PhD awarded in science in the U.S.[16] Only a decade after the successful flights by the Wright brothers, the 1920s saw extensive development of aeronautical engineering through development of World War I military aircraft. Meanwhile, research to provide fundamental background science continued by combining theoretical physics with experiments. In 1990, with the rise of computer technology, the first search engine was built by computer engineer Alan Emtage. [edit] Main branches of engineering Main article: List of engineering branches Engineering, much like other science, is a broad discipline which is often broken down into several sub-disciplines. These disciplines concern themselves with differing areas of engineering work. Although initially an engineer will usually be trained in a specific discipline, throughout an engineer's career the engineer may become multi-disciplined, having worked in several of the outlined areas. Engineering is often characterized as having four main branches:[17][18] * Chemical engineering – The exploitation of chemical principles in order to carry out large scale chemical process, as well as designing new specialty materials and fuels. * Civil engineering – The design and construction of public and private works, such as infrastructure (roads, railways, water supply and treatment etc.), bridges and buildings. * Electrical engineering – a very broad area that may encompass the design and study of various electrical & electronic systems, such as electrical circuits, generators, motors, electromagnetic/electromechanical devices, electronic devices, electronic circuits, optical fibers, optoelectronic devices, computer systems, telecommunications and electronics. * Mechanical engineering – The design of physical or mechanical systems, such as power and energy systems, aerospace/aircraft products, weapon systems, transportation products engines, compressors, powertrains, kinematic chains, vacuum technology, and vibration isolation equipment. Beyond these four, sources vary on other main branches. Historically, naval engineering and mining engineering were major branches. Modern fields sometimes included as major branches include aerospace, architectural, biomedical[19] industrial, and nuclear engineering.[citation needed] New specialties sometimes combine with the traditional fields and form new branches. A new or emerging area of application will commonly be defined temporarily as a permutation or subset of existing disciplines; there is often gray area as to when a given sub-field becomes large and/or prominent enough to warrant classification as a new "branch." One key indicator of such emergence is when major universities start establishing departments and programs in the new field. For each of these fields there exists considerable overlap, especially in the areas of the application of sciences to their disciplines such as physics, chemistry and mathematics. [edit] Methodology Design of a turbine requires collaboration of engineers from many fields, as the system is subject to mechanical, electro-magnetic and chemical processes. The blades, rotor and stator as well as the steam cycle all need to be carefully designed and optimised. Engineers apply the sciences of physics and mathematics to find suitable solutions to problems or to make improvements to the status quo. More than ever, engineers are now required to have knowledge of relevant sciences for their design projects, as a result, they keep on learning new material throughout their career. If multiple options exist, engineers weigh different design choices on their merits and choose the solution that best matches the requirements. The crucial and unique task of the engineer is to identify, understand, and interpret the constraints on a design in order to produce a successful result. It is usually not enough to build a technically successful product; it must also meet further requirements. Constraints may include available resources, physical, imaginative or technical limitations, flexibility for future modifications and additions, and other factors, such as requirements for cost, safety, marketability, productibility, and serviceability. By understanding the constraints, engineers derive specifications for the limits within which a viable object or system may be produced and operated. [edit] Problem solving Engineers use their knowledge of science, mathematics, logic, economics, and appropriate experience or tacit knowledge to find suitable solutions to a problem. Creating an appropriate mathematical model of a problem allows them to analyze it (sometimes definitively), and to test potential solutions. Usually multiple reasonable solutions exist, so engineers must evaluate the different design choices on their merits and choose the solution that best meets their requirements. Genrich Altshuller, after gathering statistics on a large number of patents, suggested that compromises are at the heart of "low-level" engineering designs, while at a higher level the best design is one which eliminates the core contradiction causing the problem. Engineers typically attempt to predict how well their designs will perform to their specifications prior to full-scale production. They use, among other things: prototypes, scale models, simulations, destructive tests, nondestructive tests, and stress tests. Testing ensures that products will perform as expected. Engineers as professionals take seriously their responsibility to produce designs that will perform as expected and will not cause unintended harm to the public at large. Engineers typically include a factor of safety in their designs to reduce the risk of unexpected failure. However, the greater the safety factor, the less efficient the design may be. The study of failed products is known as forensic engineering, and can help the product designer in evaluating his or her design in the light of real conditions. The discipline is of greatest value after disasters, such as bridge collapses, when careful analysis is needed to establish the cause or causes of the failure. [edit] Computer use A computer simulation of high velocity air flow around the Space Shuttle during re-entry. Solutions to the flow require modelling of the combined effects of the fluid flow and heat equations. As with all modern scientific and technological endeavors, computers and software play an increasingly important role. As well as the typical business application software there are a number of computer aided applications (Computer-aided technologies) specifically for engineering. Computers can be used to generate models of fundamental physical processes, which can be solved using numerical methods. One of the most widely used tools in the profession is computer-aided design (CAD) software which enables engineers to create 3D models, 2D drawings, and schematics of their designs. CAD together with Digital mockup (DMU) and CAE software such as finite element method analysis or analytic element method allows engineers to create models of designs that can be analyzed without having to make expensive and time-consuming physical prototypes. These allow products and components to be checked for flaws; assess fit and assembly; study ergonomics; and to analyze static and dynamic characteristics of systems such as stresses, temperatures, electromagnetic emissions, electrical currents and voltages, digital logic levels, fluid flows, and kinematics. Access and distribution of all this information is generally organized with the use of Product Data Management software.[20] There are also many tools to support specific engineering tasks such as Computer-aided manufacture (CAM) software to generate CNC machining instructions; Manufacturing Process Management software for production engineering; EDA for printed circuit board (PCB) and circuit schematics for electronic engineers; MRO applications for maintenance management; and AEC software for civil engineering. In recent years the use of computer software to aid the development of goods has collectively come to be known as Product Lifecycle Management (PLM).[21] [edit] Social context This section may contain original research. Please improve it by verifying the claims made and adding references. Statements consisting only of original research may be removed. More details may be available on the talk page. (July 2010) Engineering is a subject that ranges from large collaborations to small individual projects. Almost all engineering projects are beholden to some sort of financing agency: a company, a set of investors, or a government. The few types of engineering that are minimally constrained by such issues are pro bono engineering and open design engineering. By its very nature engineering is bound up with society and human behavior. Every product or construction used by modern society will have been influenced by engineering design. Engineering design is a very powerful tool to make changes to environment, society and economies, and its application brings with it a great responsibility. Many engineering societies have established codes of practice and codes of ethics to guide members and inform the public at large. Engineering projects can be subject to controversy. Examples from different engineering disciplines include the development of nuclear weapons, the Three Gorges Dam, the design and use of Sport utility vehicles and the extraction of oil. In response, some western engineering companies have enacted serious corporate and social responsibility policies. Engineering is a key driver of human development.[22] Sub-Saharan Africa in particular has a very small engineering capacity which results in many African nations being unable to develop crucial infrastructure without outside aid. The attainment of many of the Millennium Development Goals requires the achievement of sufficient engineering capacity to develop infrastructure and sustainable technological development.[23] All overseas development and relief NGOs make considerable use of engineers to apply solutions in disaster and development scenarios. A number of charitable organizations aim to use engineering directly for the good of mankind: * Engineers Without Borders * Engineers Against Poverty * Registered Engineers for Disaster Relief * Engineers for a Sustainable World [edit] Relationships with other disciplines [edit] Science Scientists study the world as it is; engineers create the world that has never been. —Theodore von Kármán Bioreactors for producing proteins, NRC Biotechnology Research Institute, Montréal, Canada There exists an overlap between the sciences and engineering practice; in engineering, one applies science. Both areas of endeavor rely on accurate observation of materials and phenomena. Both use mathematics and classification criteria to analyze and communicate observations. Scientists are expected to interpret their observations and to make expert recommendations for practical action based on those interpretations[citation needed]. Scientists may also have to complete engineering tasks, such as designing experimental apparatus or building prototypes. Conversely, in the process of developing technology engineers sometimes find themselves exploring new phenomena, thus becoming, for the moment, scientists. In the book What Engineers Know and How They Know It,[24] Walter Vincenti asserts that engineering research has a character different from that of scientific research. First, it often deals with areas in which the basic physics and/or chemistry are well understood, but the problems themselves are too complex to solve in an exact manner. Examples are the use of numerical approximations to the Navier-Stokes equations to describe aerodynamic flow over an aircraft, or the use of Miner's rule to calculate fatigue damage. Second, engineering research employs many semi-empirical methods that are foreign to pure scientific research, one example being the method of parameter variation. As stated by Fung et al. in the revision to the classic engineering text, Foundations of Solid Mechanics: "Engineering is quite different from science. Scientists try to understand nature. Engineers try to make things that do not exist in nature. Engineers stress invention. To embody an invention the engineer must put his idea in concrete terms, and design something that people can use. That something can be a device, a gadget, a material, a method, a computing program, an innovative experiment, a new solution to a problem, or an improvement on what is existing. Since a design has to be concrete, it must have its geometry, dimensions, and characteristic numbers. Almost all engineers working on new designs find that they do not have all the needed information. Most often, they are limited by insufficient scientific knowledge. Thus they study mathematics, physics, chemistry, biology and mechanics. Often they have to add to the sciences relevant to their profession. Thus engineering sciences are born."[25] Although engineering solutions make use of scientific principles, engineers must also take into account safety, efficiency, economy, reliability and constructibility or ease of fabrication, as well as legal considerations such as patent infringement or liability in the case of failure of the solution. [edit] Medicine and biology Leonardo da Vinci, seen here in a self-portrait, has been described as the epitome of the artist/engineer.[26] He is also known for his studies on human anatomy and physiognomy The study of the human body, albeit from different directions and for different purposes, is an important common link between medicine and some engineering disciplines. Medicine aims to sustain, enhance and even replace functions of the human body, if necessary, through the use of technology. Modern medicine can replace several of the body's functions through the use of artificial organs and can significantly alter the function of the human body through artificial devices such as, for example, brain implants and pacemakers.[27][28] The fields of Bionics and medical Bionics are dedicated to the study of synthetic implants pertaining to natural systems. Conversely, some engineering disciplines view the human body as a biological machine worth studying, and are dedicated to emulating many of its functions by replacing biology with technology. This has led to fields such as artificial intelligence, neural networks, fuzzy logic, and robotics. There are also substantial interdisciplinary interactions between engineering and medicine.[29][30] Both fields provide solutions to real world problems. This often requires moving forward before phenomena are completely understood in a more rigorous scientific sense and therefore experimentation and empirical knowledge is an integral part of both. Medicine, in part, studies the function of the human body. The human body, as a biological machine, has many functions that can be modeled using Engineering methods.[31] The heart for example functions much like a pump,[32] the skeleton is like a linked structure with levers,[33] the brain produces electrical signals etc.[34] These similarities as well as the increasing importance and application of Engineering principles in Medicine, led to the development of the field of biomedical engineering that uses concepts developed in both disciplines. Newly emerging branches of science, such as Systems biology, are adapting analytical tools traditionally used for engineering, such as systems modeling and computational analysis, to the description of biological systems.[31] [edit] Art A drawing for a booster engine for steam locomotives. Engineering is applied to design, with emphasis on function and the utilization of mathematics and science. There are connections between engineering and art;[35] they are direct in some fields, for example, architecture, landscape architecture and industrial design (even to the extent that these disciplines may sometimes be included in a University's Faculty of Engineering); and indirect in others.[35][36][37][38] The Art Institute of Chicago, for instance, held an exhibition about the art of NASA's aerospace design.[39] Robert Maillart's bridge design is perceived by some to have been deliberately artistic.[40] At the University of South Florida, an engineering professor, through a grant with the National Science Foundation, has developed a course that connects art and engineering.[36][41] Among famous historical figures Leonardo Da Vinci is a well known Renaissance artist and engineer, and a prime example of the nexus between art and engineering.[26][42] [edit] Other fields In Political science the term engineering has been borrowed for the study of the subjects of Social engineering and Political engineering, which deal with forming political and social structures using engineering methodology coupled with political science principles. Financial engineering has similarly borrowed the term. [edit] See also Main article: Outline of engineering Lists * List of basic engineering topics * List of engineering topics * List of engineers * Engineering society * List of aerospace engineering topics * List of basic chemical engineering topics * List of electrical engineering topics * List of genetic engineering topics * List of mechanical engineering topics * List of nanoengineering topics * List of software engineering topics Nuvola apps kcmsystem.svg Engineering portal Related subjects * Controversies over the term Engineer * Design * Earthquake engineering * Engineer * Engineering economics * Engineering education * Engineers Without Borders * Forensic engineering * Global Engineering Education * Industrial design * Infrastructure * Open hardware * Reverse engineering * Science and technology * Structural failure * Sustainable engineering * Women in engineering [edit]
  • design Return to the top
  • Design, when applied to fashion, includes considering aesthetics as well as function in the final form. Design as a noun informally refers to a plan for the construction of an object (as in architectural blueprints, circuit diagrams and sewing patterns) while “to design” (verb) refers to making this plan.[1] No generally-accepted definition of “design” exists,[2] and the term has different connotations in different fields (see design disciplines below). However, one can also design by directly constructing an object (as in pottery, cowboy coding and graphic design). More formally, design has been defined as follows. (noun) a specification of an object, manifested by an agent, intended to accomplish goals, in a particular environment, using a set of primitive components, satisfying a set of requirements, subject to constraints; (verb, transitive) to create a design, in an environment (where the designer operates)[3] Here, a "specification" can be manifested as either a plan or a finished product and "primitives" are the elements from which the design object is composed. With such a broad denotation, there is no universal language or unifying institution for designers of all disciplines. This allows for many differing philosophies and approaches toward the subject (see Philosophies and studies of design, below). The person designing is called a designer, which is also a term used for people who work professionally in one of the various design areas, usually also specifying which area is being dealt with (such as a fashion designer, concept designer or web designer). A designer’s sequence of activities is called a design process.[4] The scientific study of design is called design science. Designing often necessitates considering the aesthetic, functional, economic and sociopolitical dimensions of both the design object and design process. It may involve considerable research, thought, modeling, interactive adjustment, and re-design. Meanwhile, diverse kinds of objects may be designed, including clothing, graphical user interfaces, skyscrapers, corporate identities, business processes and even methods of designing. Design as a process Substantial disagreement exists concerning how designers in many fields, whether amateur or professional, alone or in teams, produce designs. Dorst and Dijkhuis argued that “there are many ways of describing design processes” and discussed “two basic and fundamentally different ways”,[7] both of which have several names. The prevailing view has been called “The Rational Model”,[8] “Technical Problem Solving”[9] and “The Reason-Centric Perspective”.[10] The alternative view has been called “Reflection-in-Action”,[9] “co-evolution” [11] and “The Action-Centric Perspective”.[10] [edit] The Rational Model The Rational Model was independently developed by Simon [12] and Pahl and Beitz.[13] It posits that: 1. designers attempt to optimize a design candidate for known constraints and objectives, 2. the design process is plan-driven, 3. the design process is understood in terms of a discrete sequence of stages. The Rational Model is based on a rationalist philosophy [14] and underlies the Waterfall Model,[15] Systems Development Life Cycle [16] and much of the engineering design literature.[17] [edit] Example sequence of stages Typical stages consistent with The Rational Model include the following. * Pre-production design o Design brief or Parti – an early (often the beginning) statement of design goals o Analysis – analysis of current design goals o Research – investigating similar design solutions in the field or related topics o Specification – specifying requirements of a design solution for a product (product design specification[18]) or service. o Problem solving – conceptualizing and documenting design solutions o Presentation – presenting design solutions * Design during production o Development – continuation and improvement of a designed solution o Testing – in situ testing a designed solution * Post-production design feedback for future designs o Implementation – introducing the designed solution into the environment o Evaluation and conclusion – summary of process and results, including constructive criticism and suggestions for future improvements * Redesign – any or all stages in the design process repeated (with corrections made) at any time before, during, or after production. Each stage has many associated best practices.[19] [edit] Criticism of The Rational Model The Rational Model has been widely criticized on two primary grounds 1. Designers do not work this way – extensive empirical evidence has demonstrated that designers do not act as the rational model suggests.[20] 2. Unrealistic assumptions – goals are often unknown when a design project begins, and the requirements and constraints continue to change.[21] [edit] The Action-Centric Model The Action-Centric Perspective is a label given to a collection of interrelated concepts, which are antithetical to The Rational Model.[10] It posits that: 1. designers use creativity and emotion to generate design candidates, 2. the design process is improvised, 3. no universal sequence of stages is apparent – analysis, design and implementation are contemporary and inextricably linked [10] The Action-Centric Perspective is a based on an empiricist philosophy and broadly consistent with the Agile approach [22] and amethodical development.[23] Substantial empirical evidence supports the veracity of this perspective in describing the actions of real designers.[20] [edit] Descriptions of design activities At least two views of design activity are consistent with the Action-Centric Perspective. Both involve three basic activities. In the Reflection-in-Action paradigm, designers alternate between “framing,” “making moves,” and “evaluate moves”. “Framing” refers to conceptualizing the problem, i.e., defining goals and objectives. A “move” is a (tentative) design decision.[9] In the Sensemaking-Coevolution-Implementation Framework, designers alternate between its three titular activities. Sensemaking includes both framing and evaluating moves. Implementation is the process of constructing the design object. Coevolution is “the process where the design agent simultaneously refines its mental picture of the design object based on its mental picture of the context, and vice versa”.[24] A design approach is a general philosophy that may or may not include a guide for specific methods. Some are to guide the overall goal of the design. Other approaches are to guide the tendencies of the designer. A combination of approaches may be used if they don't conflict. Often a designer (especially in commercial situations) is not in a position to define purpose. Whether a designer is, is not, or should be concerned with purpose or intended use beyond what they are expressly hired to influence, is debatable, depending on the situation. In society, not understanding or disinterest in the wider role of design might also be attributed to the commissioning agent or client, rather than the designer. In structuration theory, achieving consensus and fulfillment of purpose is as continuous as society. Raised levels of achievement often lead to raised expectations. Design is both medium and outcome, generating a Janus-like face, with every ending marking a new beginning. [edit] Terminology The word "design" is often considered ambiguous depending on the application. The new terminal at Barajas airport in Madrid, Spain [edit] Design and art Design is often viewed as a more rigorous form of art, or art with a clearly defined purpose. The distinction is usually made when someone other than the artist is defining the purpose. In graphic arts the distinction is often made between fine art and commercial art. Applied art and decorative arts are other terms, the latter mostly used for objects from the past. In the realm of the arts, design is more relevant to the "applied" arts, such as architecture and industrial design. Today the term design is widely associated with modern industrial product design as initiated by Raymond Loewy and teachings at the Bauhaus and Ulm School of Design (HfG Ulm) in Germany during the 20th Century. Design implies a conscious effort to create something that is both functional and aesthetically pleasing. For example, a graphic artist may design an advertisement poster. This person's job is to communicate the advertisement message (functional aspect) and to make it look good (aesthetically pleasing). The distinction between pure and applied arts is not completely clear, but one may consider Jackson Pollock's (often criticized as "splatter") paintings as an example of pure art. One may assume his art does not convey a message based on the obvious differences between an advertisement poster and the mere possibility of an abstract message of a Jackson Pollock painting. One may speculate that Pollock, when painting, worked more intuitively than would a graphic artist, when consciously designing a poster. However, Mark Getlein suggests the principles of design are "almost instinctive", "built-in", "natural", and part of "our sense of 'rightness'."[26] Pollock, as a trained artist, may have utilized design whether conscious or not. A drawing for a booster engine for steam locomotives. Engineering is applied to design, with emphasis on function and the utilization of mathematics and science. [edit] Design and engineering Engineering is often viewed as a more rigorous form of design. Contrary views suggest that design is a component of engineering aside from production and other operations which utilize engineering. A neutral view may suggest that design and engineering simply overlap, depending on the discipline of design. The American Heritage Dictionary defines design as: "To conceive or fashion in the mind; invent," and "To formulate a plan", and defines engineering as: "The application of scientific and mathematical principles to practical ends such as the design, manufacture, and operation of efficient and economical structures, machines, processes, and systems.".[27][28] Both are forms of problem-solving with a defined distinction being the application of "scientific and mathematical principles". How much science is applied in a design is a question of what is considered "science". Along with the question of what is considered science, there is social science versus natural science. Scientists at Xerox PARC made the distinction of design versus engineering at "moving minds" versus "moving atoms". Jonathan Ive has received several awards for his design of Apple Inc. products like this laptop. In some design fields, personal computers are also used for both design and production Design and production The relationship between design and production is one of planning and executing. In theory, the plan should anticipate and compensate for potential problems in the execution process. Design involves problem-solving and creativity. In contrast, production involves a routine or pre-planned process. A design may also be a mere plan that does not include a production or engineering process, although a working knowledge of such processes is usually expected of designers. In some cases, it may be unnecessary and/or impractical to expect a designer with a broad multidisciplinary knowledge required for such designs to also have a detailed specialized knowledge of how to produce the product. Design and production are intertwined in many creative professional careers, meaning problem-solving is part of execution and the reverse. As the cost of rearrangement increases, the need for separating design from production increases as well. For example, a high-budget project, such as a skyscraper, requires separating (design) architecture from (production) construction. A Low-budget project, such as a locally printed office party invitation flyer, can be rearranged and printed dozens of times at the low cost of a few sheets of paper, a few drops of ink, and less than one hour's pay of a desktop publisher. This is not to say that production never involves problem-solving or creativity, nor that design always involves creativity. Designs are rarely perfect and are sometimes repetitive. The imperfection of a design may task a production position (e.g. production artist, construction worker) with utilizing creativity or problem-solving skills to compensate for what was overlooked in the design process. Likewise, a design may be a simple repetition (copy) of a known preexisting solution, requiring minimal, if any, creativity or problem-solving skills from the designer. An example of a business workflow process using Business Process Modeling Notation. Process design "Process design" (in contrast to "design process" mentioned above) refers to the planning of routine steps of a process aside from the expected result. Processes (in general) are treated as a product of design, not the method of design. The term originated with the industrial designing of chemical processes. With the increasing complexities of the information age, consultants and executives have found the term useful to describe the design of business processes as well as manufacturing processes.
  • microdermabrasion Return to the top
  • Microdermabrasion has become an increasingly popular method for facial rejuvenation. In 2010, microdermabrasion was one of the top five non-surgical procedures for men and women according to the American Society for Aesthetic Plastic Surgery (ASAPS). Microdermabrasion is a non-invasive mechanical exfoliation treatment that removes the outermost layer of dead skin cells on the face, chest, neck or anywhere on the body. Mechanical exfoliation with or without particles, along with adjustable vacuum pressure, allows for safe controlled exfoliation of the top layers of the epidermis. It’s an in-office procedure that is done by a trained skin care professional that uses a mechanical medium for exfoliation (crystals, diamond tips, bristle tips) along with vacuum to sweep away the dead skin and helps with circulation. [1] Contents [hide] * 1 How microdermabrasion renews the skin * 2 Benefits of microdermabrasion * 3 History of microdermabrasion * 4 Microdermabrasion today o 4.1 Microdermabrasion mediums * 5 References * 6 External Link [edit] How microdermabrasion renews the skin The skin’s surface is disrupted, cell division occurs which stimulates fibroblast activity leading to collagen which leads to thicker, firmer skin. The suctioning and vacuuming stimulates blood flow bringing up O2 and nutrients to the skin's surface and helps to nourish the dermis. O2 also helps with acneic skin because oxygen kills the acne bacteria in blemishes. Human skin sloughs off at a slower rate with age, so the exfoliation of several layers of the stratum corneum leaves skin fresh and radiant. Microdermabrasion treatments are recommended every two weeks in a series of six for correction and every four to eight weeks for maintenance or prevention. [2] [edit] Benefits of microdermabrasion Microdermabrasion can be done to decrease the appearance of superficial hyperpigmentation, photo-damage, diminish fine lines, wrinkles, and shallow acne scars which helps to even out the texture. Removing the dead skin will aid in the penetration of skin care products by up to 50% and makeup will go on much more smoothly. [3] [edit] History of microdermabrasion The first microdermabrasion unit was developed in Italy in 1985, using small inert aluminum oxide crystals to abrade the skin. In 1986, other European markets had introduced the technology, which was immediately adopted by physicians for mechanical exfoliation. There were 10 microdermabrasion units on the market in Europe by the end 0f 1992. In 1996, Mattioli Engineering partnered with one of the Italian designed machines and started working towards meeting FDA requirements for the USA. By the end of 1996, the FDA issued the first clearance letter for microdermabrasion machines. In January 1997, the first microderm machine was being sold and marketed in the US. The diamond tip was introduced in 1999 and the bristle tip was introduced in 2005. [4] [edit] Microdermabrasion today Microdermabrasion has evolved from rocks, stones and shells to crystals, particle-free diamond tips and particle-free bristle tips. The popular, preferred method of mechanical exfoliation is particle-free over crystals. Once the desired amount of exfoliation has been reached, some microdermabrasion units will then infuse a skin specific solution into the skin. By infusing the solution, it will penetrate deeper than if applied manually for two reasons; the first is because the dead skin has been removed, so product penetration increases, the second is because the vacuum pressure works in reverse to push it in deeper. Results are significantly greater from microdermabrasion treatments combined with an infusion technique. [5] [edit] Microdermabrasion mediums (crystals, diamond tips, bristle tips) 1) Aluminum Oxide Crystals: fourth most abundant compound in earth’s crust; second to the diamond for hardness; known for it’s hardness & chemical inertness; inhaled crystals must be <5 microns to reach the alveoli, Aluminum Oxide Crystals are 100 microns; aluminum oxide crystals are chemically inert and pose no hazard; graded for purity; professional grade is 98.9% pure; irregularly shaped for effective exfoliation.[6] 2) Sodium Bicarbonate & Sodium Chloride Crystals: soft & regular in shape; more uncomfortable because a higher velocity is required; water-soluble and can be absorbed into the skin; power to exfoliate is 25% that of aluminum oxide. 3) Organic Grains (crystals): used to buff & polish; crystals are made from trees, plants, agricultural crops, straw, reeds, maize, sunflower, cane sugar; non-toxic; great for sensitive skin; not as popular as other mediums used for microdermabrasion. 4) Diamond Tips: hardest natural substance; erythema (redness) is partially due to circulation rather than only irritation; no risk of inhalation or particles remaining imbedded in the skin; varied coarseness of diamond wands or tips; diamond tips able to fit some crystal microdermabrators; diamond tips tend to dull from buildup of dead skin during treatment. [7] 5) Bristle Tips: bristles are pliable, so they move with the skin allowing for aggressive treatments without added irritation; made from polyester or nylon; less likely to stripe or mark the skin; erythema (redness) is due to circulation as well as abrasion; various bristle tips range from fine to coarse/abrasive; no risk of inhalation of particles or remaining particles imbedded in the skin.[5] [edit] References 1. ^ Dermatologic Surgery 2001; 27: 2031-1034. 2. ^ Dermatologic Surgery 27 (2001): 1031-1034. 3. ^ Microdermabrasion in Practice. 1995. Mahuzier, Francois MD. 4. ^ Dermatologic Surgery 28 (2002): 390-393. 5. ^ a b "Improving Your Appearance | Christopher B. Zachary FRCP". Drzachary.net. http://www.drzachary.net/services/cosmetic-aesthetic-services/improving-your-appearance/. Retrieved 2010-11-14. 6. ^ "WWW.REVERSITAL.NET + The next generation of Microdermabrasion !". Reversital.net. http://reversital.net/howitworks.shtml. Retrieved 2010-11-14. 7. ^ Cosmetic Dermatology. 2005. Cheryl Burgess, MD, Ed.
  • devices Return to the top
  • A tool is a device that can be used to produce or achieve something, but that is not consumed in the process. Colloquially a tool can also be a procedure or process used for a specific purpose. Tools that are used in particular fields or activities may have different designations such as Instrument, Utensil, Implement, Machine, Apparatus. Contents [hide] * 1 Evolution of tool use * 2 Tool use by animals * 3 Functions o 3.1 Tool substitution + 3.1.1 Multi-use tools * 4 History * 5 See also * 6 References [edit] Evolution of tool use Anthropologists believe that the use of tools was an important step in the evolution of mankind.[1] Humans evolved an opposable thumb — useful in holding tools — and increased dramatically in intelligence, which aided in the use of tools.[2] Tools are the most important items that the ancient humans used to climb to the top of the food chain; by inventing tools, they were able to accomplish tasks that human bodies could not, such as using a spear or bow and arrow to kill prey, since their teeth were not sharp enough to pierce many animals' skins. A telephone is a communication tool that interfaces between two people engaged in conversation at one level. And between each user and the communication network at another. It is in the domain of media and communications technology that a counter-intuitive aspect of our relationships with our tools first began to gain popular recognition. Marshall McLuhan famously said "We shape our tools. And then our tools shape us." McLuhan was referring to the fact that our social practices co-evolve with our use of new tools and the refinements we make to existing tools. Carpentry tools recovered from the wreck of a 16th century sailing ship, the Mary Rose. [edit] Tool use by animals Main article: Tool use by animals Observation has confirmed that that multiple species can use tools, including monkeys, apes, several birds, and sea otters. Philosophers originally thought that only humans had the ability to make tools, until zoologists observed birds[3] and monkeys[4][5][6] making tools. Now humans' unique relationship to tools is considered to be that we are the only species that uses tools to make other tools.[citation needed] [edit] Functions The basic functions of tools are: * Cutting tools, such as the knife, scythe or sickle, are wedge-shaped implements that produce a shearing force along a narrow face. Ideally, the edge of the tool needs to be harder than the material being cut or else the blade will become dulled with repeated use. But even resilient tools will require periodic sharpening, which is the process of removing deformation wear from the edge. Also gouges and drill bits. * Moving tools move huge and tiny things, e.g. concentrating force tools like the hammer moves a nail, the maul moves a stake, or a whip moves flesh on a horse. These operate by applying physical compression to a surface. In the case of the screwdriver, the force is rotational and called torque. Writing implements deliver a fluid to a surface via compression to activate the ink cartridge. Also grabbing and twisting nuts and bolts with pliers, a glove, a wrench, etc. All these tools move items by some kind of force. Also Trucks, Rockets and Planes move larger items and particle accelerators move very small items. * Tools that enact chemical changes, including temperature and ignition, such as lighters and blowtorches. * Guiding, measuring and perception tools include the ruler, glasses, set square, sensors, straightedge, theodolite, microscope, monitor, clock, phone, printer * Shaping tools, such as moulds, jigs, trowels. * Fastening tools, such as welders, rivet guns, nail guns, or glue guns. * Information and data manipulation tools, such as computers, middleware, IDE, spreadsheets Some tools may be combinations of other tools. An alarm-clock is for example a combination of a measuring tool (the clock) and a perception tool (the alarm). This enables the alarm-clock to be a tool that falls outside of all the categories mentioned above. Protective gear items are not considered tools, because they do not directly help perform work, just protect the worker like ordinary clothing. Personal protective equipment includes such items as gloves, safety glasses, ear defenders and biohazard suits.
  • tanning gun Return to the top
  • An airbrush is a small, air-operated tool that sprays various media including ink and dye, but most often paint by a process of nebulization. Spray guns developed from the airbrush and are still considered a type of airbrush. Contents [hide] * 1 History * 2 Design * 3 Types o 3.1 Trigger o 3.2 Feed system o 3.3 Mix point * 4 Spray guns * 5 Technique * 6 Use o 6.1 Art and illustration o 6.2 Photo retouching o 6.3 Murals o 6.4 Hobby o 6.5 Airbrush makeup application o 6.6 Temporary airbrush tattoos (TATs) o 6.7 Airbrush tanning o 6.8 Finger nail art o 6.9 Clothing o 6.10 Automotive * 7 Street artists * 8 Safety * 9 See also * 10 References * 11 External links [edit] History The first airbrush, depending on your definition, was patented in 1876 (Patent Number 182,389) by Francis Edgar Stanley of Newton, Massachusetts. Stanley and his twin brother later invented a process for continuously coating photographic plates (Stanley Dry Plate Company) but are perhaps best known for their Stanley Steamer. No artistic images that used this 'paint distributor / atomiser' exist or are as yet known. The first instrument to be named the "airbrush" was developed by Abner Peeler "for the painting of watercolors and other artistic purposes" and used a hand-operated compressor. It was rather crude, being based on a number of spare parts in a jeweller's workshop such as old screwdrivers and welding torches. It took 4 years of further development before a truly practical device was developed. This was marketed by Liberty Walkup, who taught airbrush technique to American Impressionist master Wilson Irvine at the Air Brush School in Rockford, Illinois. The first certain 'atomising' type airbrush was invented by Charles Burdick in 1893 and presented by Thayer and Chandler art materials company at the World Columbian Exposition in Chicago. This device was essentially the same as a modern airbrush, resembling a pen and working in a different manner than Peeler's device. Aerograph, Burdick's original company, still makes and sells airbrushes in England. Thayer and Chandler were acquired by Badger Air-Brush Co. in 2000. Badger Air-Brush continues the Thayer and Chandler tradition of manufacturing quality airbrush guns, tools and compressors out of Franklin Park, Illinois. For more a detailed academic study, the University of Wales Library holds a detailed PhD on Airbrush History. The Franklin Institute in Philadelphia, The Public Library in Rockford Illinois and the Conservation Department of New York University retain copies. This was authored by Dr. Andy Penaluna, now Professor of Creative Entrepreneurship at Swansea Metropolitan University.[1] Professor Penaluna has also advised the International Museum of Photography at George Eastman House, Rochester, New York. [edit] Design An airbrush works by passing a stream of fast moving (compressed) air through a venturi, which creates a local reduction in air pressure (suction) that allows paint to be pulled from an interconnected reservoir at normal atmospheric pressure. The high velocity of the air atomizes the paint into very tiny droplets as it blows past a very fine paint-metering component. The paint is carried onto paper or other surface. The operator controls the amount of paint using a variable trigger which opens more or less a very fine tapered needle that is the control element of the paint-metering component. An extremely fine degree of atomization is what allows an artist to create such smooth blending effects using the airbrush. The technique allows for the blending of two or more colors in a seamless way, with one color slowly becoming another color. Freehand airbrushed images, without the aid of stencils or friskets, have a floating quality, with softly defined edges between colors, and between foreground and background colors. A well skilled airbrush artist can produce paintings of photographic realism or can simulate almost any painting medium. Painting at this skill level involves supplementary tools, such as masks and friskets, and very careful planning. Some airbrushes use pressures as low as 20 psi (1.38 bar) while others use pressures in the region of 30-35 psi (2-2.4 bar). Larger "spray guns" as used for automobile spray-painting need 100 psi (6.8 bar) or more to adequately atomize a thicker paint using less solvent. They are capable of delivering a heavier coating more rapidly over a wide area. Even with small artist airbrushes using acrylic paint, artists must be careful not to breathe in the atomized paint, which floats in the air for minutes and can go deep into the lungs. With commercial spray guns for automobiles, it is vital that the painter have a clean air source to breathe, because automotive paint is far more harmful to the lungs than acrylic. Certain spray guns, called High-Volume Low-Pressure (HVLP) spray guns, are designed to deliver the same high volumes of paint without requiring such high pressures. [edit] Types Aerograph Super 63, a gravity fed, double action, internal mix airbrush Airbrushes are usually classified by three characteristics. The first characteristic is the action performed by the user to trigger the paint flow while the second is the mechanism for feeding the paint into the airbrush and the third is the point at which the paint and air mix. [edit] Trigger The simplest airbrushes work with a single action mechanism where the depression of a single "trigger" results in paint and air flowing into the airbrush body and the atomized paint being expelled onto the target surface. Cheaper airbrushes and spray guns tend to be of this type. Dual action or double action airbrushes separate the function for air and paint flow so that the user can control the volume of airflow and the concentration of paintflow through two independent mechanisms. This allows for greater control and a wider variety of artistic effects. This type of airbrush is more complicated in design than single action airbrushes which tends to be reflected in its cost.
  • facial Return to the top
  • * jugum * forfend * affable * egregious facial - 9 dictionary results Pompano Beach Facial 1 ridiculously huge coupon a day. It's like Pompano Beach at 90% off! www.Groupon.com/Fort-Lauderdale/ Healthy Skin Facials Massage Envy® of West Boca Raton. Schedule an Appointment Today. www.massageenvy.com 50-90% Off Spa Facials Huge Discounts 50-90% Off City's Best For Women. Subscribe Free Now! www.CoupTessa.com/Fort-Lauderdale fa·cial    /ˈfeɪʃəl/ Show Spelled[fey-shuhl] Show IPA –adjective 1. of the face: facial expression. 2. for the face: a facial cream. –noun 3. a treatment to beautify the face. Use facial in a Sentence See images of facial Search facial on the Web Origin: 1600–10; 1910–15 for def. 3; < ML faciālis. See face, -al1 —Related forms fa·cial·ly, adverb Dictionary.com Unabridged Based on the Random House Dictionary, © Random House, Inc. 2011. Cite This Source | Link To facial Explore the Visual Thesaurus » Related Words for : facial facial nerve, nervus facialis, seventh cranial nerve View more related words » Dictionary.com Free Toolbar Define Facial Instantly. Faster Page Loads With Fewer Ads. Dictionary.com World English Dictionary facia (ˈfeɪʃɪə) [Click for IPA pronunciation guide] — n a variant spelling of fascia 'facial — adj facial (ˈfeɪʃəl) [Click for IPA pronunciation guide] — adj 1. of or relating to the face — n 2. a beauty treatment for the face, involving cleansing, massage, and cosmetic packs 'facially — adv fascia or facia (ˈfeɪʃɪə) [Click for IPA pronunciation guide] — n , pl -ciae 1. the flat surface above a shop window 2. architect a flat band or surface, esp a part of an architrave or cornice 3. fibrous connective tissue occurring in sheets beneath the surface of the skin and between muscles and groups of muscles 4. biology a distinctive band of colour, as on an insect or plant 5. ( Brit ) a less common name for dashboard 6. a casing that fits over a mobile phone, with spaces for the buttons [C16: from Latin: band: related to fascis bundle; see fasces ] facia or facia (ˈfeɪʃɪə, -ʃɪˌiː, ˈfæʃɪə) [Click for IPA pronunciation guide] — n [C16: from Latin: band: related to fascis bundle; see fasces ] 'fascial or facia — adj 'facial or facia — adj Collins English Dictionary - Complete & Unabridged 10th Edition 2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009 Cite This Source Word Origin & History facial c.1600, from Fr. facial , from M.L. facialis of the face, from facies (see face (n.)). The noun meaning beauty treatment for the face is from 1914. Online Etymology Dictionary, © 2010 Douglas Harper Cite This Source Medical Dictionary 1 fa·cial definition Pronunciation: /ˈfā-shəl/ Function: adj 1 : of, relating to, or affecting the face < facial neuralgia> 2 : concerned with or used in improving the appearance of the face 3 : relating to or being the buccal and labial surface of a tooth fa·cial·ly Pronunciation: /-shə-lē/ Function: adv 2 facial definition Function: n 1 : a treatment to improve the appearance of the face 2 : a facial part (as a nerve or artery) Merriam-Webster's Medical Dictionary, © 2007 Merriam-Webster, Inc. Cite This Source facial fa·cial (fā'shəl) adj. Relating to the face. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. Cite This Source Legal Dictionary Main Entry: fa·cial Function: adjective : involving or apparent from the face of something (as a statute) < facial discrimination> facial challenge to the law> —fa·cial·ly adverb Merriam-Webster's Dictionary of Law, © 1996 Merriam-Webster, Inc. Cite This Source Famous Quotations facial "Every word, facial expression, gesture, or action on th..." "It is difficult to compare Chaplin's and Keaton's gifts..." "How often our involuntary facial motions testify to the..." "I've noticed over the years that kids who are allowed t..." "... [Washington] is always an entertaining spectacle. L..." More Quotes
  • ionic Return to the top
  • An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass ("go") between electrodes in a solution, when an electric field is applied. It is from Greek ιον, meaning "going." The word ion also is responsible for electrical current being symbolized by the letter i in chemistry and physics. An anion (pronounced /ˈæn.aɪ.ən/ AN-eye-ən), from the Greek word ἄνω (ánō), meaning "up", is an ion with more electrons than protons, giving it a net negative charge (since electrons are negatively charged and protons are positively charged). Conversely, a cation (pronounced /ˈkæt.aɪ.ən/ KAT-eye-ən), from the Greek word κατά (katá), meaning "down", is an ion with fewer electrons than protons, giving it a positive charge. Since the charge on a proton is equal in magnitude to the charge on an electron, the net charge on an ion is equal to the number of protons in the ion minus the number of electrons. An ion consisting of a single atom is an atomic or monatomic ion; if it consists of two or more atoms, it is a molecular or polyatomic ion. Contents [hide] * 1 General o 1.1 History and Discovery o 1.2 Characteristics o 1.3 Natural Occurrences + 1.3.1 Astronomical + 1.3.2 Terrestrial + 1.3.3 Biological o 1.4 Related Technology o 1.5 Portrayal in Literature and Media * 2 Chemistry o 2.1 Notation + 2.1.1 Denoting the charged state + 2.1.2 Sub-classes o 2.2 Formation + 2.2.1 Formation of monatomic ions + 2.2.2 Formation of polyatomic and molecular ions + 2.2.3 Ionization potential o 2.3 Ionic bonding o 2.4 Chemical Applications + 2.4.1 Mass Spectroscopy + 2.4.2 Catalysis # 2.4.2.1 Transition Metal Ions Catalysis # 2.4.2.2 Templated Synthesis of Organic Compounds o 2.5 Common ions * 3 See also * 4 References General Wiki letter w cropped.svg This section requires expansion. History and Discovery Etymologically the word ion is the Greek ιον (going), the present participle of ιεναι, ienai, "to go." This term was introduced by English physicist and chemist Michael Faraday in 1834 for the (then unknown) species that goes from one electrode to the other through an aqueous medium.[1][2] Faraday did not know the nature of these species, but he knew that since metals disolved into and entered solution at one electrode, and new metal came forth from solution at the other electrode, that some kind of substance moved through the solution in a current, conveying matter from one place to the other. Faraday also introduced the words anion and cation. In Faraday's nomenclature, cations were named because they were attracted to the cathode in a galvanic device and anions were named due to their attraction to the cathode. (For the origin of these names in turn, see the accompanying linked articles). Characteristics Ions in their gas-like state are highly reactive, and not present in large amounts in the daily environment of Earth (their major occurance is is flames, lightning and electrical sparks, and other plasmas). These gas-like ions rapidly interact with ions of opposite charge to give neutral molecules or ionic salts. Ions are also produced in the liquid or solid state whatn salts interact with solvents (for example, water) to produce "solvated ions," which are more stable, for reasons involving a combination of energy and entropy changes as the ions move away from each other to interact with the liquid. These stabilized species are more commonly found in the environment at low temperatures. A common example is the ions present in seawater, which are derived from the disolved salts there. All ions are charged, which means that like all charged objects they are: * attracted to opposite electric charges (positive to negative, and vice versa), * repelled by like charges, and * when moving, travel in trajectories that are deflected by a magnetic field. Electrons, due to their smaller mass and thus larger space-filling properties as matter waves, determine the size of atoms and molecules that possess any electrons at all. Thus, anions (negatively charged ions) are larger than the parent molecule or atom, as the excess electron(s) repel each other, and add to the physical size of the ion, because its size is determined by its electron cloud. Conversely, cations are generally smaller than the corresponding parent atom or molecule, for the same reason. One particular cation (that of hydrogen) contains no electrons, and thus is very much smaller than the parent hydrogen atom. Natural Occurrences Ions are ubiquitous in nature and are responsible for diverse phenomena from the luminescence of the Sun, and the existence of ionosphere on Earth. Atoms in their ionic state may have a different color from neutral atoms, and thus light absorption by metal ions gives the color of gemstones. In both inorganic and organic chemistry (including biochemistry), the interaction of water and ions is extremely important (an example is the energy that drives breakdown of ATP. The following sections describe contexts in which ions feature prominently and are arranged in decreasing physical length-scale, from the astronomical to the microscopic. Astronomical The remnant of "Tycho's Supernova", a huge ball of expanding plasma. The outer shell shown in blue is X-ray emission by high-speed electrons. Main article: Plasma (physics) A collection of non-aqueous gas-like ions, or even a gas containing a proportion of charged particles, is called a plasma. >99.9% of visible matter in the Universe may be in the form of plasmas.[3] These include our Sun and other stars, the space between planets, as well as the space in between stars. Plasmas are often called the fourth state of matter because its properties are substantially different from solids, liquids, and gases. Astrophysical plasmas containing predominantly a mixture of electrons and protons (ionized hydrogen). Terrestrial ionosphere, salinity and ionic composition of water Biological ion gradient across membrane, co-factors and catalysis Related Technology Ions can be non-chemically prepared using various ion sources, usually involving high voltage or temperature. These are used in a multitude of devices such as mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines. As reactive charged particles, they are also used in air purification by disrupting microbes, and in household items such as smoke detectors. As signaling and metabolism in organisms are controlled by a precise ionic gradient across membranes, the disruption of this gradient contributes to cell death. This is a common mechanism exploited by natural and artificial biocides, including the ion channels gramicidin and amphotericin (a fungicide). Inorganic dissolved ions are a component of total dissolved solids, an indicator of water quality in the world. Portrayal in Literature and Media Chemistry Notation Denoting the charged state Equivalent notations for an iron atom (Fe) that lost two electrons. When writing the chemical formula for an ion, its net charge is written in superscript immediately after the chemical structure for the molecule/atom. The net charge is written with the magnitude before the sign; that is, a doubly charged cation is indicated as 2+ instead of +2. Conventionally the magnitude of the charge is omitted for singly charged molecules/atoms; for example, the sodium cation is indicated as Na+ and not Na1+. An alternative (and acceptable) way of showing a molecule/atom with multiple charges is by drawing out the signs multiple times; this is often seen with transition metals. Chemists sometimes circle the sign; this is merely ornamental and does not alter the chemical meaning. All three representations of Fe2+ shown in the figure are thus equivalent. Mixed Roman numerals and charge notations for the uranyl ion. The oxidation state of the metal is shown as superscripted Roman numerals, whereas the charge of the entire complex is shown by the angle symbol together with the magnitude and sign of the net charge. Monatomic ions are sometimes also denoted with Roman numerals; for example, the Fe2+ example seen above is occasionally referred to as Fe(II) or FeII. The Roman numeral designates the formal oxidation state of an element, whereas the superscripted numerals denotes the net charge. The two notations are therefore exchangeable for monatomic ions, but the Roman numerals cannot be applied to polyatomic ions. It is however possible to mix the notations for the individual metal center with a polyatomic complex, as shown by the uranyl ion example. Sub-classes If an ion contains unpaired electrons, it is called a radical ion. Just like uncharged radicals, radical ions are very reactive. Polyatomic ions containing oxygen, such as carbonate and sulfate, are called oxyanions. Molecular ions that contain at least one carbon to hydrogen bond are called organic ions. If the charge in an organic ion is formally centered on a carbon, it is termed a carbocation (if positively charged) or carboanion (if negatively charged). Formation Formation of monatomic ions Monatomic ions are formed by the addition of electrons to the valence shell of the atom, which is the outer-most electron shell in an atom, or the losing of electrons from this shell. The inner shells of an atom are filled with electrons that are tightly bound to the positively charged atomic nucleus, and so do not participate in this kind of chemical interaction. The process of gaining or losing electrons from a neutral atom or molecule is called ionization. Atoms can be ionized by bombardment with radiation, but the more usual process of ionization encountered in chemistry is the transfer of electrons between atoms or molecules. This transfer is usually driven by the attaining of stable ("closed shell") electronic configurations. Atoms will gain or lose electrons depending on which action takes the least energy. For example, a sodium atom, Na, has a single electron in its valence shell, surrounding 2 stable, filled inner shells of 2 and 8 electrons. Since these filled shells are very stable, a sodium atom tends to lose its extra electron and attain this stable configuration, becoming a sodium cation in the process Na → Na+ + e− On the other hand, a chlorine atom, Cl, has 7 electrons in its valence shell, which is one short of the stable, filled shell with 8 electrons. Thus, a chlorine atom tends to gain an extra electron and attain a stable 8-electron configuration, becoming a chloride anion in the process: Cl + e− → Cl− This driving force is what causes sodium and chlorine to undergo a chemical reaction, where the "extra" electron is transferred from sodium to chlorine, forming sodium cations and chloride anions. Being oppositely charged, these cations and anions form ionic bonds and combine together to form sodium chloride, NaCl, more commonly known as rock salt. Na+ + Cl− → NaCl Formation of polyatomic and molecular ions An electrostatic potential map of the nitrate ion (NO− 3). The 3-dimensional shell represents a single arbitrary isopotential. Polyatomic and molecular ions are often formed by the gaining or losing of elemental ions such as H+ in neutral molecules. For example, when ammonia, NH3, accepts a proton, H+, it forms the ammonium ion, NH+ 4. Ammonia and ammonium have the same number of electrons in essentially the same electronic configuration, but ammonium has an extra proton that gives it a net positive charge. Ammonia can also lose an electron to gain a positive charge, forming the ion ·NH+ 3. However, this ion is unstable, because it has an incomplete valence shell around the nitrogen atom, making it a very reactive radical ion. Due to the instability of radical ions, polyatomic and molecular ions are usually formed by gaining or losing elemental ions such as H+, rather than gaining or losing electrons. This allows the molecule to preserve its stable electronic configuration while acquiring an electrical charge. Ionization potential Main article: Ionization potential The energy required to detach an electron in its lowest energy state from an atom or molecule of a gas with less net electric charge is called the ionization potential, or ionization energy. The nth ionization energy of an atom is the energy required to detach its nth electron after the first n − 1 electrons have already been detached. Each successive ionization energy is markedly greater than the last. Particularly great increases occur after any given block of atomic orbitals is exhausted of electrons. For this reason, ions tend to form in ways that leave them with full orbital blocks. For example, sodium has one valence electron in its outermost shell, so in ionized form it is commonly found with one lost electron, as Na+. On the other side of the periodic table, chlorine has seven valence electrons, so in ionized form it is commonly found with one gained electron, as Cl−. Caesium has the lowest measured ionization energy of all the elements and helium has the greatest.[4] The ionization energy of metals is generally much lower than the ionization energy of nonmetals, which is why metals will generally lose electrons to form positively charged ions while nonmetals will generally gain electrons to form negatively charged ions. Ionic bonding Main article: Ionic bond Ionic bonding is a kind of chemical bonding that arises from the mutual attraction of oppositely charged ions. Since ions of like charge repel each other, they do not usually exist on their own. Instead, many of them may form a crystal lattice, in which ions of opposite charge are bound to each other. The resulting compound is called an ionic compound, and is said to be held together by ionic bonding. In ionic compounds there arise characteristic distances between ion neighbors from which the spatial extension and the ionic radius of individual ions may be derived. The most common type of ionic bonding is seen in compounds of metals and nonmetals (except noble gases, which rarely form chemical compounds). Metals are characterized by having a small number of electrons in excess of a stable, closed-shell electronic configuration. As such, they have the tendency to lose these extra electrons in order to attain a stable configuration. This property is known as electropositivity. Non-metals, on the other hand, are characterized by having an electron configuration just a few electrons short of a stable configuration. As such, they have the tendency to gain more electrons in order to achieve a stable configuration. This tendency is known as electronegativity. When a highly electropositive metal is combined with a highly electronegative nonmetal, the extra electrons from the metal atoms are transferred to the electron-deficient nonmetal atoms. This reaction produces metal cations and nonmetal anions, which are attracted to each other to form a salt
  • hair dryer Return to the top
  • A blowdryer or hairdryer is an electromechanical device designed to blow cool or hot air over wet or damp hair, in order to accelerate the evaporation of water particles and dry the hair. Blowdryers allow to better control the shape and style of hair, by accelerating and controlling the formation of temporary hydrogen bonds inside each strand. These hydrogen bonds are very powerful (allowing for stronger hair shaping than even the sulfur bonds formed by permanent waving products), but are temporary and extremely vulnerable to humidity. They disappear with a single washing of the hair. The normal use of a hairdryer Hairstyles using blowdryers usually have volume and discipline, which can be further improved by the use of styling products and hairbrushes during drying to add tension, hold and lift. Blowdryers were invented around the end of the 19th century. The first model was created by Alexander Godefroy in his salon in France in 1890. The handheld, household hair-dryer first appeared in 1920. Blowdryers are used both in the beauty salon by professional stylists, and in the average household by consumers. Contents [hide] * 1 Function * 2 History * 3 See also * 4 Notes * 5 References [edit] Function An early blow dryer Most models use coils of wire that have a high electric resistivity and heats rapidly with an electric current. A fan usually blows ambient air past the hot coils resulting in heated air effective for drying. The heating element in most hairdryers is a bare, coiled nichrome wire that is wrapped around insulating mica heating boards. Nichrome wire is used in heating elements, because of two important properties: it is a poor conductor of electricity and it does not oxidize when heated.[1] In terms of modern models, a survey of stores in 2007 showed that most hair dryers have ceramic heating elements (like ceramic heaters)—because of their “instant heat” capability. This means that it takes less time for the dryers to heat up, and thus it takes a lot less time for the hair to dry.[2] Many of these hair dryers have “cool shot” buttons which turn off the heater and just blow room temperature air while the button is pressed. This function is useful in helping to maintain the hairstyle by setting it. The cold air also reduces frizz and can help to bolster the shine in the hair.[3] Many also feature “ionic” operation, to reduce the amount of static electricity build-up in the hair. Manufacturers also claim this makes the hair “smoother.” Some stylists today consider the introduction of ionic technology to be one of the most important advances in the beauty industry.[2] Hair dryers are available with different attachments including a diffuser attachment. . These attachments include a diffuser, an airflow concentrator, and a comb nozzle attachment . A diffuser is an attachment that is used on hair that is fine, colored, permed or naturally curly. It works by diffusing the heat so that the hair dries more slowly at a cooler temperature. This makes it so that the hair is less likely to frizz and it gives the hair more volume. An airflow concentrator does the exact opposite of a diffuser. It makes the end of the blowdryer more narrow and thus helps to concentrate the heat into one spot in order to make it dry rapidly. The comb nozzle attachment is the same as the airflow concentrator, but it ends with comb-like teeth so that the user can dry their hair using just the dryer without a brush or comb. It also consumes the most energy in a household. [edit] History Hairdryer made by AEG, about 1935 Before the invention of the hairdryer, it was actually common for men and women to dry their hair using the vacuum cleaner. In fact, the original model of hairdryer was invented in the 1890 by Alexandre Goldefroy by taking inspiration from the vacuum cleaner.[4] Alexandre invented it for usage in his hair salon in France and it was not portable or handheld, but instead could only be used by having the woman sit underneath it. However, it was not until the 1920s that the hairdryer began to go on the market in handheld form. This was due to innovations by US Racine Universal Motor Company and the Hamilton Beach Co. that allowed the hairdryer to be handheld. Even in the 1920s the new hairdryers were often heavy, weighing in at approximately 2 lbs, and difficult to use. They also had many instances of overheating and electrocution. It was also only capable of using 100 watts so it took a lot longer to dry hair (the average hairdryer today can use up to 2000 watts of heat).[5] Since the 1920s, development of the hairdryer has mainly focused on improving the wattage and superficial exterior and material changes. In fact, the mechanisms of the hairdryer has not had any significant changes since its inception. One of the more important changes for the hairdryer is having the materials change to plastic so that it is more lightweight. This really caught on in the 1960s with the introduction of better electrical motors and the improvement of plastics. Another important change happened in 1954 when GEC changed the design of the dryer to move the motor inside the casing.[6] Also, including safety mechanisms in them has been important, especially since Consumer Product Safety Commission set up guidelines in the 1970s that hairdryers had to meet in order to be considered safe to manufacture. Since 1991 the CPSC has mandated by US law that all dryers must use a ground fault circuit interrupter so that it cannot electrocute a person if it gets wet.[7] By the year 2000 deaths by blowdryers had dropped to less than four people a year, a stark difference to the hundreds of cases of electrocution accidents during the mid-twentieth century. In terms of positive health, this type of hairdryer has also been cited as an effective treatment for head lice.[8] Overall, the size, weight, noise, and appearance of the hairdryer has dramatically changed from the heavy bulky noisy contraptions of the early part of the twentieth century, to the streamlined plastic that people are used to today. There are two other major types of blowdryers other than the hand held. These are the bonnet hairdryer and the rigid-hood hairdryer. The bonnet hairdryer was introduced to consumers in 1951. This type of dryer worked by having the dryer, usually in a small portable box, connected to a tube that went into a bonnet with holes in it that could be placed on top of a persons head. This worked by giving an even amount of heat to the whole head at once. The 50s also saw the introduction of the rigid-hood hair dryer which is the type most frequently seen in salons, and it had a hard plastic helmet that goes over the head. This dryer works similarly to the bonnet hairdryer but at a much higher wattage.
  • ultrasonic Return to the top
  • An ultrasonic cleaner, sometimes called a sonicator, is a cleaning device that uses ultrasound (usually from 20–400 kHz) and an appropriate cleaning solvent (sometimes ordinary tap water) to clean delicate items. The ultrasound can be used with only water but solvent is advised; it enhances the effect of a solvent appropriate for the item to be cleaned and the soiling. Ultrasonic cleaners are often used to clean jewellery, lenses and other optical parts, watches, dental and surgical instruments, fountain pens, industrial parts and electronic equipment. They are used in many jewellery workshops, watchmakers' establishments, and electronic repair workshops. Contents [hide] * 1 Process characteristics * 2 Design and operating principle * 3 Cleaning solution * 4 Uses * 5 See also * 6 References * 7 External links [edit] Process characteristics Ultrasonic cleaning uses high frequency sound waves to agitate in an aqueous or organic compound. Cavitation bubbles induced by the agitation act on contaminants adhering to substrates like metals, plastics, glass, rubber, and ceramics. This action also penetrates blind holes, cracks, and recesses. The intention is to thoroughly remove all traces of contamination tightly adhering or embedded onto solid surfaces. Water or other solvents can be used, depending on the type of contamination and the workpiece. Contaminants can include dust, dirt, oil, pigments, grease, polishing compounds, flux agents, fingerprints, soot wax and mold release agents, biological soil like blood, and so on. Ultrasonic cleaning can be used for a wide range of workpiece shapes, sizes and materials, and may not require the part to be disassembled prior to cleaning.[1] [edit] Design and operating principle In an ultrasonic cleaner, the object to be cleaned is placed in a chamber containing a suitable solution (in an aqueous or organic solution, depending on the application). In aqueous cleaners, the chemical added is a surfactant which breaks down the surface tension of the water base. An ultrasound generating transducer built into the chamber, or lowered into the fluid, produces ultrasonic waves in the fluid by changing size in concert with an electrical signal oscillating at ultrasonic frequency. This creates compression waves in the liquid of the tank which ‘tear’ the liquid apart, leaving behind many millions of microscopic ‘voids’ or ‘partial vacuum bubbles’ (cavitation). These bubbles collapse with enormous energy; temperatures of 10,000 K and pressures of 50,000 lbs per square inch have been reported[citation needed]; however, they are so small that they do no more than clean and remove surface dirt and contaminants. The higher the frequency, the smaller the nodes between the cavitation points, which allows for cleaning of more intricate detail. Ultrasonic transducers showing ~20 kHz and ~40 kHz stacks. The active elements (near the top) are two rings of lead zirconate titanate, which are bolted to an aluminium coupling horn. Transducers are usually made of piezoelectric material (e.g. lead zirconate titanate or barium titanate), and sometimes magnetostrictive (made of a material such as nickel or ferrite). The often harsh chemicals used as cleaners in many industries are not needed, or used in much lower concentrations, with ultrasonic agitation. Ultrasonics are used for industrial cleaning, and also used in many medical and dental techniques and industrial processes. [edit] Cleaning solution Ultrasonic activity (cavitation) helps the solution to do its job; plain water would not normally be effective. The cleaning solution contains ingredients designed to make ultrasonic cleaning more effective. For example, reduction of surface tension increases cavitation levels, so the solution contains a good wetting agent (surfactant). Aqueous cleaning solutions contain detergents, wetting agents and other components, and have a large influence on the cleaning process. Correct composition of the solution is very dependent upon the item cleaned. Solutions are mostly used warm, at about 50–65 °C (122–149 °F), however, in medical applications it is generally accepted that cleaning should be at temperatures below 38 °C (100 °F) to prevent protein coagulation. Water-based solutions are more limited in their ability to remove contaminants by chemical action alone than solvent solutions; e.g. for delicate parts covered with thick grease. The effort required to design an effective aqueous-cleaning system for a particular purpose is much greater than for a solvent system. Some better machines (which are not unduly large) recycle the hydrocarbon cleaning fluids. Three tanks are used in a a cascade. The lower tank containing dirty fluid is heated causing the fluid to evaporate. At the top of the machine there is a refrigeration coil. Fluid condenses on the coil and falls into the upper tank. The upper tank eventually overflows and clean fluid runs into the work tank where the cleaning takes place. Purchase price is higher than simpler machines, but such machines are economical in the long run. The same fluid can be reused many times, minimising wastage and pollution. Carbon tetrachloride (CCl4, also formerly used in fire extinguishers for electrical fires) was used in the past, but is now prohibited as dangerous. If CCl4 fumes are inhaled through a lit cigarette, carbonyl chloride (COCl2, also called phosgene, a poison gas used in warfare) could be produced.
  • manufacture Return to the top
  • Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale. Such finished goods may be used for manufacturing other, more complex products, such as aircraft, household appliances or automobiles, or sold to wholesalers, who in turn sell them to retailers, who then sell them to end users – the "consumers". Manufacturing takes turns under all types of economic systems. In a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more frequently directed by the state to supply a centrally planned economy. In free market economies, manufacturing occurs under some degree of government regulation. Modern manufacturing includes all intermediate processes required for the production and integration of a product's components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead. The manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in the North America include General Motors Corporation, General Electric, and Pfizer. Examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Toyota, Samsung, and Bridgestone. Contents [hide] * 1 History and development o 1.1 Manufacturing systems: The changing methods of manufacturing * 2 Economics of manufacturing * 3 Manufacturing and investment around the world * 4 Taxonomy of manufacturing processes * 5 Manufacturing categories * 6 Theories * 7 Control * 8 See also * 9 References * 10 Sources * 11 External links [edit] History and development * In its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. Training was by apprenticeship. In much of the pre-industrial world the guild system protected the privileges and trade secrets of urban artisans. * Before the Industrial Revolution, most manufacturing occurred in rural areas, where household-based manufacturing served as a supplemental subsistence strategy to agriculture (and continues to do so in places). Entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. * Toil manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm. [edit] Manufacturing systems: The changing methods of manufacturing * Craft or Guild system * Putting-out system * English system of manufacturing * American system of manufacturing * Soviet collectivism in manufacturing * Mass production * Just In Time manufacturing * Lean manufacturing * Flexible manufacturing * Mass customization * Agile manufacturing * Rapid manufacturing * Prefabrication * Packaging and labeling * Ownership * Fabrication * Publication [edit] Economics of manufacturing According to some economists, manufacturing is a wealth-producing sector of an economy, whereas a service sector tends to be wealth-consuming.[1][2] Emerging technologies have provided some new growth in advanced manufacturing employment opportunities in the Manufacturing Belt in the United States. Manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs. The clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks. Developed countries regulate manufacturing activity with labor laws and environmental laws. In the U.S, manufacturers are subject to regulations by the Occupational Safety and Health Administration and the United States Environmental Protection Agency. In Europe, pollution taxes to offset environmental costs are another form of regulation on manufacturing activity. Labor Unions and craft guilds have played a historic role negotiation of worker rights and wages. Environment laws and labor protections that are available in developed nations may not be available in the third world. Tort law and product liability impose additional costs on manufacturing. Manufacturing requires huge amounts of fossil fuels. The construction of a single car in the United States requires, on average, at least 20 barrels of oil.[3] [edit] Manufacturing and investment around the world Surveys and analyses of trends and issues in manufacturing and investment around the world focus on such things as: * the nature and sources of the considerable variations that occur cross-nationally in levels of manufacturing and wider industrial-economic growth; * competitiveness; and * attractiveness to foreign direct investors. In addition to general overviews, researchers have examined the features and factors affecting particular key aspects of manufacturing development. They have compared production and investment in a range of Western and non-Western countries and presented case studies of growth and performance in important individual industries and market-economic sectors.[4][5] On June 26, 2009, Jeff Immelt, the CEO of General Electric, called for the United States to increase its manufacturing base employment to 20% of the workforce, commenting that the U.S. has outsourced too much in some areas and can no longer rely on the financial sector and consumer spending to drive demand.[6] A total of 3.2 million – one in six U.S. manufacturing jobs – have disappeared between 2000 and 2007.[7] [edit] Taxonomy of manufacturing processes * Taxonomy of manufacturing processes * Manufacturing Process Management [edit] Manufacturing categories * Chemical industry o Pharmaceutical * Construction * Electronics o Semiconductor * Engineering o Biotechnology o Emerging technologies o Nanotechnology o Synthetic biology, Bioengineering * Energy industry * Food and Beverage o Agribusiness o Brewing industry o Food processing * Industrial design o Interchangeable parts * Metalworking o Smith o Machinist o Machine tools o Cutting tools (metalworking) o Free machining o Tool and die maker o Global steel industry trends o Steel production * Metalcasting * Plastics * Telecommunications * Textile manufacturing o Clothing industry o Sailmaker o Tentmaking * Transportation o Aerospace manufacturing o Automotive industry o Bus manufacturing o Tire manufacturing [edit] Theories * Taylorism * Fordism * Scientific management [edit] Control * Management o List of management topics o Total Quality Management * Quality control o Six Sigma [edit] See also Main article: Outline of manufacturing * Howstuffismade [edit] References 1. ^ Friedman, David (2006). "No Light at the End of the Tunnel". Los Angeles Times. New America Foundation. http://www.newamerica.net/publications/articles/2002/no_light_at_the_end_of_the_tunnel. Retrieved 2007-05-12. 2. ^ Joseph, Keith (1976). "Monetarism Is Not Enough". Center for Policy Studies. Margaret Thatcher Foundation. http://www.margaretthatcher.org/commentary/displaydocument.asp?docid=110796. Retrieved 2007-05-12. 3. ^ "World oil supplies are set to run out faster than expected, warn scientists". The Independent. June 14, 2007. 4. ^ Manufacturing & Investment Around The World: An International Survey Of Factors Affecting Growth & Performance, ISR Publications/Google Books, revised second edition, 2002. ISBN 978-0-906321-25-6. 5. ^ [1] 6. ^ Bailey, David and Soyoung Kim (June 26, 2009).GE's Immelt says U.S. economy needs industrial renewal.UK Guardian.. Retrieved on June 28, 2009. 7. ^ "Factory jobs: 3 million lost since 2000". USATODAY.com. April 20, 2007. [edit] Sources 1. Kalpakjian, Serope; Steven Schmid (August 2005). Manufacturing, Engineering & Technology. Prentice Hall. pp. 22–36, 951–988. ISBN 0-1314-8965-8. [edit] External links Look up manufacturing in Wiktionary, the free dictionary. Wikimedia Commons has media related to: Manufacturing * Cato Institute article:Thriving in a Global Economy: The Truth about U.S. Manufacturing and Trade * How Everyday Things Are Made: video presentations. * TIME Magazine article on American manufacturing's global effectiveness * Grant Thornton IBR 2008 Manufacturing industry focus * Process vs. Discrete Manufacturing Summary * MFGWatch - Quarterly Survey of North American Manufacturers [hide]v · d · eTechnology (outline) Applied science Archaeology · Artificial intelligence · Ceramic · Computing · Cryogenics · Electronics · Energy · Energy storage · Engineering geology · Engineering physics · Environmental engineering science · Environmental technology · Fisheries science · Hydraulics · Management · Materials science · Microtechnology · Nanotechnology · Nuclear technology · Particle physics · Technician · Technologist · Zoography Information Graphics · Information and communication technologies · Information technology · Music technology · Speech recognition · Systematics · Visual technology Industry Building officials · Business informatics · Construction · Financial · Fishing · Industrial technology · Machinery · Manufacturing · Mining · Textile Military Ammunition · Army engineering maintenance · Bombs · Military communications · Military engineering · Military technology Domestic Domestic appliances · Domestic technology · Educational technology · Food technology Engineering Aerospace · Agricultural · Architectural · Audio · Biochemical · Biological · Broadcast · Chemical · Civil · Computer · Construction · Control · Electrical · Electronic · Enterprise · Entertainment · Environmental · Food · Genetic · Industrial · Mechanical · Mechatronics · Metallurgy · Mining · Network · Nuclear · Ocean · Ontology · Optical · Petroleum · Protein · Radio Frequency · Software · Structural · Systems · Telecommunications Health / safety Bioinformatics · Biomechatronics · Biomedical · Biotechnology · Cheminformatics · Fire protection · Health science · Medical technology · Nutrition · Pharmacology · Safety · Sanitary · Tissue Transport Aerospace · Aerospace engineering · Automotive · Motor vehicles · Naval architecture · Space technology · Traffic · Transport Retrieved from "http://en.wikipedia.org/wiki/Manufacturing" Categories: Industry | Manufacturing Personal tools * Log in / create account Namespaces * Article * Discussion Variants Views * Read * Edit * View history Actions Search Search Navigation * Main page * Contents * Featured content * Current events * Random article * Donate to Wikipedia Interaction * Help * About Wikipedia * Community portal * Recent changes * Contact Wikipedia Toolbox * What links here * Related changes * Upload file * Special pages * Permanent link * Cite this page Print/export * Create a book * Download as PDF * Printable version Languages * العربية * Azərbaycanca * Česky * Dansk * Deutsch * Español * فارسی * Français * 한국어 * Italiano * עברית * Қазақша * Lietuvių * မြန်မာဘာသာ * Nederlands * 日本語 * ‪Norsk (bokmål)‬ * Polski * Português * Română * Русский * සිංහල * Simple English * Suomi * Svenska * Tagalog * Türkçe * Українська * Tiếng Việt * ייִדיש * Žemaitėška * 中文 * This page was last modified on 1 February 2011 at 17:24.
  • Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale. Such finished goods may be used for manufacturing other, more complex products, such as aircraft, household appliances or automobiles, or sold to wholesalers, who in turn sell them to retailers, who then sell them to end users – the "consumers". Manufacturing takes turns under all types of economic systems. In a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more frequently directed by the state to supply a centrally planned economy. In free market economies, manufacturing occurs under some degree of government regulation. Modern manufacturing includes all intermediate processes required for the production and integration of a product's components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead. The manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in the North America include General Motors Corporation, General Electric, and Pfizer. Examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Toyota, Samsung, and Bridgestone. Contents [hide] * 1 History and development o 1.1 Manufacturing systems: The changing methods of manufacturing * 2 Economics of manufacturing * 3 Manufacturing and investment around the world * 4 Taxonomy of manufacturing processes * 5 Manufacturing categories * 6 Theories * 7 Control * 8 See also * 9 References * 10 Sources * 11 External links [edit] History and development * In its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. Training was by apprenticeship. In much of the pre-industrial world the guild system protected the privileges and trade secrets of urban artisans. * Before the Industrial Revolution, most manufacturing occurred in rural areas, where household-based manufacturing served as a supplemental subsistence strategy to agriculture (and continues to do so in places). Entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. * Toil manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm. [edit] Manufacturing systems: The changing methods of manufacturing * Craft or Guild system * Putting-out system * English system of manufacturing * American system of manufacturing * Soviet collectivism in manufacturing * Mass production * Just In Time manufacturing * Lean manufacturing * Flexible manufacturing * Mass customization * Agile manufacturing * Rapid manufacturing * Prefabrication * Packaging and labeling * Ownership * Fabrication * Publication [edit] Economics of manufacturing According to some economists, manufacturing is a wealth-producing sector of an economy, whereas a service sector tends to be wealth-consuming.[1][2] Emerging technologies have provided some new growth in advanced manufacturing employment opportunities in the Manufacturing Belt in the United States. Manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs. The clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks. Developed countries regulate manufacturing activity with labor laws and environmental laws. In the U.S, manufacturers are subject to regulations by the Occupational Safety and Health Administration and the United States Environmental Protection Agency. In Europe, pollution taxes to offset environmental costs are another form of regulation on manufacturing activity. Labor Unions and craft guilds have played a historic role negotiation of worker rights and wages. Environment laws and labor protections that are available in developed nations may not be available in the third world. Tort law and product liability impose additional costs on manufacturing. Manufacturing requires huge amounts of fossil fuels. The construction of a single car in the United States requires, on average, at least 20 barrels of oil.[3] [edit] Manufacturing and investment around the world Surveys and analyses of trends and issues in manufacturing and investment around the world focus on such things as: * the nature and sources of the considerable variations that occur cross-nationally in levels of manufacturing and wider industrial-economic growth; * competitiveness; and * attractiveness to foreign direct investors. In addition to general overviews, researchers have examined the features and factors affecting particular key aspects of manufacturing development. They have compared production and investment in a range of Western and non-Western countries and presented case studies of growth and performance in important individual industries and market-economic sectors.[4][5] On June 26, 2009, Jeff Immelt, the CEO of General Electric, called for the United States to increase its manufacturing base employment to 20% of the workforce, commenting that the U.S. has outsourced too much in some areas and can no longer rely on the financial sector and consumer spending to drive demand.[6] A total of 3.2 million – one in six U.S. manufacturing jobs – have disappeared between 2000 and 2007.[7] [edit] Taxonomy of manufacturing processes * Taxonomy of manufacturing processes * Manufacturing Process Management [edit] Manufacturing categories * Chemical industry o Pharmaceutical * Construction * Electronics o Semiconductor * Engineering o Biotechnology o Emerging technologies o Nanotechnology o Synthetic biology, Bioengineering * Energy industry * Food and Beverage o Agribusiness o Brewing industry o Food processing * Industrial design o Interchangeable parts * Metalworking o Smith o Machinist o Machine tools o Cutting tools (metalworking) o Free machining o Tool and die maker o Global steel industry trends o Steel production * Metalcasting * Plastics * Telecommunications * Textile manufacturing o Clothing industry o Sailmaker o Tentmaking * Transportation o Aerospace manufacturing o Automotive industry o Bus manufacturing o Tire manufacturing [edit] Theories * Taylorism * Fordism * Scientific management [edit] Control * Management o List of management topics o Total Quality Management * Quality control o Six Sigma [edit] See also Main article: Outline of manufacturing * Howstuffismade [edit] References 1. ^ Friedman, David (2006). "No Light at the End of the Tunnel". Los Angeles Times. New America Foundation. http://www.newamerica.net/publications/articles/2002/no_light_at_the_end_of_the_tunnel. Retrieved 2007-05-12. 2. ^ Joseph, Keith (1976). "Monetarism Is Not Enough". Center for Policy Studies. Margaret Thatcher Foundation. http://www.margaretthatcher.org/commentary/displaydocument.asp?docid=110796. Retrieved 2007-05-12. 3. ^ "World oil supplies are set to run out faster than expected, warn scientists". The Independent. June 14, 2007. 4. ^ Manufacturing & Investment Around The World: An International Survey Of Factors Affecting Growth & Performance, ISR Publications/Google Books, revised second edition, 2002. ISBN 978-0-906321-25-6. 5. ^ [1] 6. ^ Bailey, David and Soyoung Kim (June 26, 2009).GE's Immelt says U.S. economy needs industrial renewal.UK Guardian.. Retrieved on June 28, 2009. 7. ^ "Factory jobs: 3 million lost since 2000". USATODAY.com. April 20, 2007. [edit] Sources 1. Kalpakjian, Serope; Steven Schmid (August 2005). Manufacturing, Engineering & Technology. Prentice Hall. pp. 22–36, 951–988. ISBN 0-1314-8965-8. [edit] External links Look up manufacturing in Wiktionary, the free dictionary. Wikimedia Commons has media related to: Manufacturing * Cato Institute article:Thriving in a Global Economy: The Truth about U.S. Manufacturing and Trade * How Everyday Things Are Made: video presentations. * TIME Magazine article on American manufacturing's global effectiveness * Grant Thornton IBR 2008 Manufacturing industry focus * Process vs. Discrete Manufacturing Summary * MFGWatch - Quarterly Survey of North American Manufacturers [hide]v · d · eTechnology Applied science Archaeology · Artificial intelligence · Ceramic · Computing · Cryogenics · Electronics · Energy · Energy storage · Engineering geology · Engineering physics · Environmental engineering science · Environmental technology · Fisheries science · Hydraulics · Management · Materials science · Microtechnology · Nanotechnology · Nuclear technology · Particle physics · Technician · Technologist · Zoography Information Graphics · Information and communication technologies · Information technology · Music technology · Speech recognition · Systematics · Visual technology Industry Building officials · Business informatics · Construction · Financial · Fishing · Industrial technology · Machinery · Manufacturing · Mining · Textile Military Ammunition · Army engineering maintenance · Bombs · Military communications · Military engineering · Military technology · Military technology and equipment · Weapons engineering Domestic Domestic appliances · Domestic technology · Educational technology · Food technology Engineering Aerospace · Agricultural · Architectural · Audio · Biochemical · Biological · Broadcast · Chemical · Civil · Computer · Construction · Control · Electrical · Electronic · Enterprise · Entertainment · Environmental · Food · Genetic · Industrial · Mechanical · Mechatronics · Metallurgy · Mining · Network · Nuclear · Ocean · Ontology · Optical · Petroleum · Protein · Radio Frequency · Software · Structural · Systems · Telecommunications Health / safety Bioinformatics · Biomechatronics · Biomedical · Biotechnology · Cheminformatics · Fire protection · Health science · Medical technology · Nutrition · Pharmacology · Safety · Sanitary · Tissue Transport Aerospace · Aerospace engineering · Automotive · Marine · Motor vehicles · Naval architecture · Space technology · Traffic · Transport
  • [close] Manufacturing From Wikipedia, the free encyclopedia (Redirected from Manufacture) Jump to: navigation, search Product’s lifecycle.svg Part of a series of articles on Industry Mill Manufacturing methods Batch production • Job production Continuous production Improvement methods LM • TPM • QRM • VDM TOC • Six Sigma • RCM Information & communication ISA-88 • ISA-95 • ERP SAP • IEC 62264 • B2MML Process control PLC • DCS Assembly of Section 41 of a Boeing 787 Dreamliner. Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale. Such finished goods may be used for manufacturing other, more complex products, such as aircraft, household appliances or automobiles, or sold to wholesalers, who in turn sell them to retailers, who then sell them to end users – the "consumers". Manufacturing takes turns under all types of economic systems. In a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more frequently directed by the state to supply a centrally planned economy. In free market economies, manufacturing occurs under some degree of government regulation. Modern manufacturing includes all intermediate processes required for the production and integration of a product's components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead. The manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in the North America include General Motors Corporation, General Electric, and Pfizer. Examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Toyota, Samsung, and Bridgestone. Contents [hide] * 1 History and development o 1.1 Manufacturing systems: The changing methods of manufacturing * 2 Economics of manufacturing * 3 Manufacturing and investment around the world * 4 Taxonomy of manufacturing processes * 5 Manufacturing categories * 6 Theories * 7 Control * 8 See also * 9 References * 10 Sources * 11 External links [edit] History and development * In its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. Training was by apprenticeship. In much of the pre-industrial world the guild system protected the privileges and trade secrets of urban artisans. * Before the Industrial Revolution, most manufacturing occurred in rural areas, where household-based manufacturing served as a supplemental subsistence strategy to agriculture (and continues to do so in places). Entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. * Toil manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm. [edit] Manufacturing systems: The changing methods of manufacturing * Craft or Guild system * Putting-out system * English system of manufacturing * American system of manufacturing * Soviet collectivism in manufacturing * Mass production * Just In Time manufacturing * Lean manufacturing * Flexible manufacturing * Mass customization * Agile manufacturing * Rapid manufacturing * Prefabrication * Packaging and labeling * Ownership * Fabrication * Publication [edit] Economics of manufacturing According to some economists, manufacturing is a wealth-producing sector of an economy, whereas a service sector tends to be wealth-consuming.[1][2] Emerging technologies have provided some new growth in advanced manufacturing employment opportunities in the Manufacturing Belt in the United States. Manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs. The clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks. Developed countries regulate manufacturing activity with labor laws and environmental laws. In the U.S, manufacturers are subject to regulations by the Occupational Safety and Health Administration and the United States Environmental Protection Agency. In Europe, pollution taxes to offset environmental costs are another form of regulation on manufacturing activity. Labor Unions and craft guilds have played a historic role negotiation of worker rights and wages. Environment laws and labor protections that are available in developed nations may not be available in the third world. Tort law and product liability impose additional costs on manufacturing. Manufacturing requires huge amounts of fossil fuels. The construction of a single car in the United States requires, on average, at least 20 barrels of oil.[3] [edit] Manufacturing and investment around the world Surveys and analyses of trends and issues in manufacturing and investment around the world focus on such things as: * the nature and sources of the considerable variations that occur cross-nationally in levels of manufacturing and wider industrial-economic growth; * competitiveness; and * attractiveness to foreign direct investors. In addition to general overviews, researchers have examined the features and factors affecting particular key aspects of manufacturing development. They have compared production and investment in a range of Western and non-Western countries and presented case studies of growth and performance in important individual industries and market-economic sectors.[4][5] On June 26, 2009, Jeff Immelt, the CEO of General Electric, called for the United States to increase its manufacturing base employment to 20% of the workforce, commenting that the U.S. has outsourced too much in some areas and can no longer rely on the financial sector and consumer spending to drive demand.[6] A total of 3.2 million – one in six U.S. manufacturing jobs – have disappeared between 2000 and 2007.[7] [edit] Taxonomy of manufacturing processes * Taxonomy of manufacturing processes * Manufacturing Process Management [edit] Manufacturing categories * Chemical industry o Pharmaceutical * Construction * Electronics o Semiconductor * Engineering o Biotechnology o Emerging technologies o Nanotechnology o Synthetic biology, Bioengineering * Energy industry * Food and Beverage o Agribusiness o Brewing industry o Food processing * Industrial design o Interchangeable parts * Metalworking o Smith o Machinist o Machine tools o Cutting tools (metalworking) o Free machining o Tool and die maker o Global steel industry trends o Steel production * Metalcasting * Plastics * Telecommunications * Textile manufacturing o Clothing industry o Sailmaker o Tentmaking * Transportation o Aerospace manufacturing o Automotive industry o Bus manufacturing o Tire manufacturing [edit] Theories * Taylorism * Fordism * Scientific management [edit] Control * Management o List of management topics o Total Quality Management * Quality control o Six Sigma [edit] See also Main article: Outline of manufacturing * Howstuffismade [edit] References 1. ^ Friedman, David (2006). "No Light at the End of the Tunnel". Los Angeles Times. New America Foundation. http://www.newamerica.net/publications/articles/2002/no_light_at_the_end_of_the_tunnel. Retrieved 2007-05-12. 2. ^ Joseph, Keith (1976). "Monetarism Is Not Enough". Center for Policy Studies. Margaret Thatcher Foundation. http://www.margaretthatcher.org/commentary/displaydocument.asp?docid=110796. Retrieved 2007-05-12. 3. ^ "World oil supplies are set to run out faster than expected, warn scientists". The Independent. June 14, 2007. 4. ^ Manufacturing & Investment Around The World: An International Survey Of Factors Affecting Growth & Performance, ISR Publications/Google Books, revised second edition, 2002. ISBN 978-0-906321-25-6. 5. ^ [1] 6. ^ Bailey, David and Soyoung Kim (June 26, 2009).GE's Immelt says U.S. economy needs industrial renewal.UK Guardian.. Retrieved on June 28, 2009. 7. ^ "Factory jobs: 3 million lost since 2000". USATODAY.com. April 20, 2007. [edit] Sources 1. Kalpakjian, Serope; Steven Schmid (August 2005). Manufacturing, Engineering & Technology. Prentice Hall. pp. 22–36, 951–988. ISBN 0-1314-8965-8. [edit] External links Look up manufacturing in Wiktionary, the free dictionary. Wikimedia Commons has media related to: Manufacturing * Cato Institute article:Thriving in a Global Economy: The Truth about U.S. Manufacturing and Trade * How Everyday Things Are Made: video presentations. * TIME Magazine article on American manufacturing's global effectiveness * Grant Thornton IBR 2008 Manufacturing industry focus * Process vs. Discrete Manufacturing Summary * MFGWatch - Quarterly Survey of North American Manufacturers [hide]v · d · eTechnology Applied science Archaeology · Artificial intelligence · Ceramic · Computing · Cryogenics · Electronics · Energy · Energy storage · Engineering geology · Engineering physics · Environmental engineering science · Environmental technology · Fisheries science · Hydraulics · Management · Materials science · Microtechnology · Nanotechnology · Nuclear technology · Particle physics · Technician · Technologist · Zoography Information Graphics · Information and communication technologies · Information technology · Music technology · Speech recognition · Systematics · Visual technology Industry Building officials · Business informatics · Construction · Financial · Fishing · Industrial technology · Machinery · Manufacturing · Mining · Textile Military Ammunition · Army engineering maintenance · Bombs · Military communications · Military engineering · Military technology · Military technology and equipment · Weapons engineering Domestic Domestic appliances · Domestic technology · Educational technology · Food technology Engineering Aerospace · Agricultural · Architectural · Audio · Biochemical · Biological · Broadcast · Chemical · Civil · Computer · Construction · Control · Electrical · Electronic · Enterprise · Entertainment · Environmental · Food · Genetic · Industrial · Mechanical · Mechatronics · Metallurgy · Mining · Network · Nuclear · Ocean · Ontology · Optical · Petroleum · Protein · Radio Frequency · Software · Structural · Systems · Telecommunications Health / safety Bioinformatics · Biomechatronics · Biomedical · Biotechnology · Cheminformatics · Fire protection · Health science · Medical technology · Nutrition · Pharmacology · Safety · Sanitary · Tissue Transport Aerospace · Aerospace engineering · Automotive · Marine · Motor vehicles · Naval architecture · Space technology · Traffic · Transport Retrieved from "http://en.wikipedia.org/wiki/Manufacturing" Categories: Industry | Manufacturing Personal tools * Log in / create account Namespaces * Article * Discussion Variants Views * Read * Edit * View history Actions Search Search Navigation * Main page * Contents * Featured content * Current events * Random article * Donate to Wikipedia Interaction * Help * About Wikipedia * Community portal * Recent changes * Contact Wikipedia Toolbox * What links here * Related changes * Upload file * Special pages * Permanent link * Cite this page Print/export * Create a book * Download as PDF * Printable version Languages * العربية * Azərbaycanca * Česky * Dansk * Deutsch * فارسی * Français * 한국어 * Italiano * עברית * Қазақша * Lietuvių * မြန်မာဘာသာ * Nederlands * 日本語 * ‪Norsk (bokmål)‬ * Polski * Português * Română * Русский * සිංහල * Simple English * Suomi * Svenska * Tagalog * Türkçe * Українська * Tiếng Việt * ייִדיש * Žemaitėška * 中文 * This page was last modified on 5 January 2011 at 16:14. * Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. 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  • cosmetic Return to the top
  • osmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and gels, deodorants, hand sanitizer, baby products, bath oils, bubble baths, bath salts, butters and many other types of products. A subset of cosmetics is called "make-up," which refers primarily to colored products intended to alter the user’s appearance. Many manufacturers distinguish between decorative cosmetics and care cosmetics. The word cosmetics derives from the Greek κοσμητική τέχνη (kosmetikē tekhnē), meaning "art of dress and ornament", from κοσμητικός (kosmētikos), "skilled in ordering or arranging"[1] and that from κόσμος (kosmos), meaning amongst others "order" and "ornament".[2] The manufacture of cosmetics is currently dominated by a small number of multinational corporations that originated in the early 20th century, but the distribution and sale of cosmetics is spread among a wide range of different businesses. The U.S. Food and Drug Administration (FDA) which regulates cosmetics in the United States[3] defines cosmetics as: "intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions." This broad definition includes, as well, any material intended for use as a component of a cosmetic product. The FDA specifically excludes soap from this category.[4] Contents [hide] * 1 History * 2 Criticism and controversy * 3 Makeup types * 4 Skin care products * 5 Ingredients o 5.1 Organic and natural ingredients * 6 Cosmetic industry * 7 Cosmetic careers * 8 See also * 9 References * 10 Further reading [edit] History Nefertiti bust with eye liner applied Main article: History of cosmetics The first archaeological evidence of cosmetics usage was found in Egypt around 3500 BC during the Ancient Egypt times with some of royalty owning make-up, such as Nefertiti, Nefertari, mask of Tutankhamun, etc. The Ancient Greeks and Romans also used cosmetics.[5][6] The Romans and Ancient Egyptians used cosmetics containing poisonous mercury and often lead. The ancient kingdom of Israel was influenced by cosmetics as recorded in the Old Testament—2 Kings 9:30 where Jezebel painted her eyelids—approximately 840 BC. The Biblical book of Esther describes various beauty treatments as well. In the Middle Ages, although its use was frowned upon by Church leaders, many women still wore cosmetics. A popular fad for women during the Middle Ages was to have a pale-skinned complexion, which was achieved through either applying pastes of lead, chalk, or flour, or by bloodletting. Women would also put white lead pigment that was known as "ceruse" on their faces to appear to have pale skin.[7] Cosmetic use was frowned upon at many points in Western history. For example, in the 19th century, make-up was used primarily by prostitutes, and Queen Victoria publicly declared makeup improper, vulgar, and acceptable only for use by actors.[8] Adolf Hitler told women that face painting was for clowns and not for the women of the master race.[citation needed] Women in the 19th century liked to be thought of as fragile ladies. They compared themselves to delicate flowers and emphasised their delicacy and femininity. They aimed always to look pale and interesting. Sometimes ladies discreetly used a little rouge on the cheeks, and used "belladonna" to dilate their eyes to make their eyes stand out more. Make-up was frowned upon in general especially during the 1870s when social etiquette became more rigid. Actresses however were allowed to use make up and famous beauties such as Sarah Bernhardt and Lillie Langtry could be powdered. Most cosmetic products available were still either chemically dubious, or found in the kitchen amid food colorings, berries and beetroot. By the middle of the 20th century, cosmetics were in widespread use by women in nearly all industrial societies around the world. Cosmetics have been in use for thousands of years. The absence of regulation of the manufacture and use of cosmetics has led to negative side effects, deformities, blindness, and even death through the ages. Examples of this were the prevalent use of ceruse (white lead), to cover the face during the Renaissance, and blindness caused by the mascara Lash Lure during the early 20th century. The worldwide annual expenditures for cosmetics today is estimated at $19 billion.[9] Of the major firms, the largest is L'Oréal, which was founded by Eugene Schueller in 1909 as the French Harmless Hair Colouring Company (now owned by Liliane Bettencourt 26% and Nestlé 28%; the remaining 46% is traded publicly). The market was developed in the USA during the 1910s by Elizabeth Arden, Helena Rubinstein, and Max Factor. These firms were joined by Revlon just before World War II and Estée Lauder just after. Beauty products are now widely available from dedicated internet-only retailers,[10] who have more recently been joined online by established outlets, including the major department stores and traditional bricks and mortar beauty retailers. Like most industries, cosmetic companies resist regulation by government agencies like the FDA, and have lobbied against this throughout the years. The FDA does not have to approve or review the cosmetics, or what goes in them before they are sold to the consumers. The FDA only regulates against the colors that can be used in the cosmetics and hair dyes. The cosmetic companies do not have to report any injuries from the products; they also only have voluntary recalls on products.[11] [edit] Criticism and controversy Further information: Campaign for Safe Cosmetics and Testing cosmetics on animals During the 20th century, the popularity of cosmetics has increased rapidly.[citation needed] Cosmetics are used by girls at an increasingly young age, especially in the United States. Due to the fast-decreasing age of make-up users, many companies, from high-street brands like Rimmel to higher-end products like Estee Lauder, have catered to this expanding market by introducing more flavored lipsticks and glosses, cosmetics packaged in glittery, sparkly packaging and marketing and advertising using young models.[citation needed] The social consequences of younger and younger beautification has had much attention in the media over the last few years. Criticism of cosmetics has come from a variety of sources including some feminists, Islamists, Christianists, animal rights activists, authors and public interest groups. There is a growing awareness and preference for cosmetics that are without any supposedly toxic ingredients, especially those derived from petroleum, sodium lauryl sulfate (SLS), and parabens.[12] Numerous published reports have raised concern over the safety of a few surfactants. SLS causes a number of skin issues including dermatitis.[13][14][15][16][17] Parabens can cause skin irritation and contact dermatitis in individuals with paraben allergies, a small percentage of the general population.[18] Animal experiments have shown that parabens have a weak estrogenic activity, acting as xenoestrogens.[19] Prolonged use of makeup has also been linked to thinning eyelashes.[20] Synthetic fragrances are widely used in consumer products. Studies concluded from patch testing show synthetic fragrances are made of many ingredients which cause allergic reactions.[21] Cosmetics companies have been criticised for making pseudoscientific claims about their products which are misleading or unsupported by scientific evidence.[22][23] [edit] Makeup types * Lipstick, lip gloss, lip liner, lip plumper, lip balm, lip conditioner, lip primer, and lip boosters.[3] * Foundation, used to smooth out the face and cover spots or uneven skin coloration. Usually a liquid, cream, or powder.[3] Foundation primer can be applied before to get a smoother finish. * Powder, used to set the foundation, giving a matte finish, and also to conceal small flaws or blemishes. * Rouge, blush or blusher, cheek coloring used to bring out the color in the cheeks and make the cheekbones appear more defined. This comes in powder, cream, and liquid forms.[3] * Bronzer, used to give skin a bit of color by adding a golden or bronze glow.[3] * Mascara is used to darken, lengthen, and thicken the eyelashes. It is available in natural colors such as brown and black, but also comes in bolder colors such as blue, pink, or purple. There are many different formulas, including waterproof for those prone to allergies or sudden tears. Often used after an eyelash curler and mascara primer.[3] Eye shadow being applied Broadway actor Jim Brochu applies make-up before the opening night of a play. The chin mask known as chutti for Kathakali, a performing art in Kerala, India is considered the thickest makeup applied for any artform. * Eyelid glue, eye liner, eye shadow, eye shimmer, and glitter eye pencils as well as different color pencils used to color and emphasize the eyelids (larger eyes give a more youthful appearance).[3] * Eyebrow pencils, creams, waxes, gels and powders are used to color and define the brows.[3] * Nail polish, used to color the fingernails and toenails.[3] * Concealer, Makeup used to cover any imperfections of the skin. Cosmetics can also be described by the form of the product, as well as the area for application. Cosmetics can be liquid or cream emulsions; powders, both pressed and loose; dispersions; and anhydrous creams or sticks. Lip stain is a cosmetic product that contains either water or a gel base. To help the product stay on the lips, many stains may contain alcohol. These lip coloring products are available in a variety of formulas, colors, and application types. The idea behind lip stains is to temporarily saturate the lips with color with a dye, rather than applying a colored wax to the lips to color them. A lip stain is usually designed to be waterproof so that the color will be long lasting, and once the stain dries, it should not smear, stain, wear unevenly, or transfer to the teeth. A lip stain may come in a bottle with an applicator which is used to brush the stain onto the lips, and it can also come in a small jar, with users applying the stain with a finger or a cosmetic brush. Make-up remover is the product used to remove the make-up products applied on the skin. It is used for cleaning the skin for other procedures, like applying any type of lotion at evening before the person go to sleep. [edit] Skin care products Also included in the general category of cosmetics are skin care products. These include creams and lotions to moisturize the face and body which are often formulated for different skin types per range, sunscreens to protect the skin from UV radiation and damage, skin lighteners, and treatment products to repair or hide skin imperfections (acne, wrinkles, dark circles under eyes, etc.), tanning oils to brown the skin. [edit] Ingredients Main article: Ingredients of cosmetics While there is assurance from the largest cosmetic companies that ingredients have passed quality tests and official regulations, and are therefore generally safe to use, there is a growing preference for cosmetics that are without any "synthetic" ingredients, especially those derived from petroleum. Once a niche market, handmade and certified organic products are becoming more mainstream. Ingredients' listings in cosmetics are highly regulated in many countries. The testing of cosmetic products on animals is a subject of some controversy. It is now illegal in the United Kingdom, the Netherlands, and Belgium, and a ban across the European Union is due to come into effect in 2009. [edit] Organic and natural ingredients Even though many cosmetic products are regulated, there are still health concerns regarding the presence of harmful chemicals within these products.[citation needed] Aside from color additives, cosmetic products and their ingredients are not subject to FDA regulation prior to their release into the market. It is only when a product is found to violate Federal Food, Drug, and Cosmetic Act (FD&C Act) and Fair Packaging and Labeling Act (FPLA) after its release that the FDA may start taking action against this violation.[24] With many new products released into the market every season, it is hard to keep track of the safety of every product. Some products carry carcinogenic contaminant 1,4- dioxane. Many cosmetic companies are coming out with "All natural" and organic products. All natural products contain mineral and plant ingredients and organic products are made with organic agricultural products. Products who claim they are organic are not, unless they are certified "USDA Organic."[25][26] See also: natural skin care [edit] Cosmetic industry The cosmetic industry is a profitable business for most manufacturers of cosmetic products. By cosmetic products, we understand anything that is intended for personal care such as skin lotions or sun lotions, makeup and other such products meant to emphasize one's look. Given the technological development and the improvement of the manufacturing process of cosmetics and not least due to the constantly increasing demand of such products, this industry reported an important growth in terms of profit. The cosmetic industry has not only grown only in the United States, but also in various parts of the world which have become famous for their cosmetic precuts. Some of these include France, Germany, Italy and Japan. It has been estimated that in Germany, the cosmetic industry generated sales of EUR 12.6 billion at retail sales, in 2008 [27] which made of German cosmetic industry the 3rd in the world, after Japan and the United States. Also, it has been shown that in the same country, this industry has grown with nearly 5 percent in one year, from 2007 to 2008. The exports of Germany in this industry reached in 2008 EUR 5.8 billion whereas the imports of cosmetics totaled EUR 3 billion.[27] The main countries that export cosmetics to Germany are France, Switzerland, the United States and Italy and they mainly consist of makeup and fragrances or perfumes for women. After the United States, Japan is the second largest market for cosmetics in the world, a market worth about JPY 1.4 trillion per year.[28] The worldwide cosmetics and perfume industry currently generates an estimated annual turnover of US$170 billion (according to Eurostaf - May 2007). Europe is the leading market, representing approximately €63 billion, while sales in France reached €6.5 billion in 2006, according to FIPAR (Fédération des Industries de la Parfumerie - the French federation for the perfume industry).[29] France is another country in which the cosmetic industry plays an important role, both nationally and internationally. Most products on whose label it is stated "Made in France" are valued on the international market. According to data from 2008, the cosmetic industry has risen constantly in France, for 40 consecutive years. In 2006, this industrial sector reached a record level of EUR 6.5 billion. Famous cosmetic brands produced in France include Vichy, Yves Saint Laurent, Yves Rocher and many others. The Italian cosmetic industry is also an important player in the European cosmetic market. Although not as large as in other European countries, the cosmetic industry in Italy was estimated to reach EUR 9 billion in 2007.[30] The Italian cosmetic industry is however dominated by hair and body products and not makeup as in many other European countries. In Italy, hair and body products make up approximately 30% of the cosmetic market. Makeup and facial care however are the first cosmetic products to be exported in the United States. Due to the popularity of cosmetics, especially fragrances and perfumes, many designers who are not necessarily involved in the cosmetic industry came up with different perfumes carrying their names. Moreover, most actors and singers also have their own perfume line (such as Celine Dion). The designer perfumes are, like any other designer products, the most expensive in the industry as the consumer pays not only for the product but also for the brand. Famous Italian fragrances are produced by Giorgio Armani, Dolce and Gabbana and so on. The European Commission and the U.S. Food and Drug Administration (FDA) are the two bodies making legislation in what concerns cosmetic industry and its various aspects within the European Union, respectively in the United States. In the European Union, the circulation of cosmetic products and their safety are law subjects since 1976. One of the newest amendments of the directive concerning cosmetic industry comes as a result of the attempt to ban animal testing. Therefore, testing cosmetic products on animals is illegal in the European Union from September 2004 and testing separate ingredients of such products on animals is also prohibited by law starting with March 2009.[31] The FDA joined with thirteen other Federal agencies in forming the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) in 1997 which is an attempt to ban animal testing and find other methods to test the cosmetic products.[32] The cosmetic industry worldwide seems to be continuously developing, now more than ever with the advent of the Internet companies. Many famous companies sell their cosmetic products online also in countries in which they do not have representatives.[33] [edit] Cosmetic careers A professional make-up artist servicing a client An account executive is responsible for visiting all department and specialty store counter sales and doors. They explain new products and "gifts with purchase" (free items given out upon purchase of a certain cosmetics item that costs more than a set amount). A beauty adviser provides product advice based on the client's skin care and makeup requirements. Beauty advisers can become certified through the Anti-Aging Beauty Institute. Supermodel Alek Wek receiving make-up from a professional. A cosmetician is a professional who provides facial and body treatments for clients. The term cosmetologist is sometimes used interchangeably with this term, but most commonly refers to a certified professional. A freelance makeup artist provides clients with beauty advice and cosmetics assistance—usually paid by the cosmetic company by the hour. Professionals in cosmetics marketing careers manage research focus groups, promote the desired brand image, and provide other marketing services (sales forecasting, allocation to different retailers, etc.). Those involved in cosmetics product development design, create and refine cosmetics products. Some positions that fall under this category include chemists, quality assurance and packaging people. Many involved within the cosmetics industry often specialize in a certain area of cosmetics such as special effects makeup or makeup techniques specific to the film, media and fashion sectors. [edit] See also * Airbrush makeup * Testing cosmetics on animals * Body art * Body hygiene kit * Cosmeceutical * Cosmetic surgery * Cosmetic, Toiletry, and Fragrance Association * Cosmetology * DEA list of chemicals * Federal Food, Drug, and Cosmetic Act * Henna * List of cosmetic ingredients * Make-up artist * Moulage * Permanent makeup * Personal care * Pharmaceuticals and personal care products in the environment * Society of Cosmetic Chemists [edit] References 1. ^ κοσμητικός, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus 2. ^ κόσμος, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus 3. ^ a b c d e f g h i Reed, Sandra I. US Department of Health and Human Services. "Cosmetics and Your Health." 2004. May 14, 2007. [1] 4. ^ Lewis, Carol. FDA. "Clearing up Cosmetic Confusion." The marketing industry is now targeting young girls to wear 'super cool lip gloss' and 'fairy glitter eye shadow', by throwing them in with toys in a box and claiming that 'girls will be girls', are they truly being girls or another plastic? 5. ^ Lesley Adkins, Roy A. Adkins, Handbook to life in Ancient Greece, Oxford University Press, 1998 6. ^ Bruno Burlando, Luisella Verotta, Laura Cornara, and Elisa Bottini-Massa, Herbal Principles in Cosmetics, CRC Press, 2010 7. ^ Rao,prathiba, cosmetics and personal care products, vol 1, pp 380-382,Elsevier inc, 1998 8. ^ Pallingston, J (1998). Lipstick: A Celebration of the World's Favorite Cosmetic. St. Martin's Press. ISBN 0312199147. 9. ^ "As Consumerism Spreads, Earth Suffers, Study Says". National Geographic: pp. 2. http://news.nationalgeographic.com/news/2004/01/0111_040112_consumerism_2.html. Retrieved 2007-08-21. 10. ^ "Lessons from categorising the entire beauty products sector (Part 1)". pp. 1. http://www.beautynow.co.uk/blog/beauty-products-part-1-522.html. Retrieved 2009-09-28. 11. ^ "cosmetics and your health." womensheatlh.gov.nd.web.4 nov 2004 12. ^ "Signers of the Compact for Safe Cosmetics". Campaign for Safe Cosmetics. Archived from the original on 2007-06-09. http://web.archive.org/web/20070609155356/http://www.safecosmetics.org/companies/signers.cfm. Retrieved 2007-07-05. 13. ^ Agner T (1991). "Susceptibility of atopic dermatitis patients to irritant dermatitis caused by sodium lauryl sulphate". Acta Derm. Venereol. 71 (4): 296–300. PMID 1681644. 14. ^ Nassif A, Chan SC, Storrs FJ, Hanifin JM (November 1994). "Abnormal skin irritancy in atopic dermatitis and in atopy without dermatitis". Arch Dermatol 130 (11): 1402–7. doi:10.1001/archderm.130.11.1402. PMID 7979441. http://www.jem.org/cgi/content/full/195/7/855. 15. ^ Marrakchi S, Maibach HI (2006). "Sodium lauryl sulfate-induced irritation in the human face: regional and age-related differences". Skin Pharmacol Physiol 19 (3): 177–80. doi:10.1159/000093112. PMID 16679819. 16. ^ CIR publication. Final Report on the Safety Assessment of Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate. Journal of the American College of Toxicology. 1983 Vol. 2 (No. 7) pages 127–181. 17. ^ Löffler H, Effendy I (May 1999). "Skin susceptibility of atopic individuals". Contact Derm. 40 (5): 239–42. doi:10.1111/j.1600-0536.1999.tb06056.x. PMID 10344477. 18. ^ Nagel JE, Fuscaldo JT, Fireman P (April 1977). "Paraben allergy". JAMA 237 (15): 1594–5. doi:10.1001/jama.237.15.1594. PMID 576658. 19. ^ Byford JR, Shaw LE, Drew MG, Pope GS, Sauer MJ, Darbre PD (January 2002). "Oestrogenic activity of parabens in MCF7 human breast cancer cells". J. Steroid Biochem. Mol. Biol. 80 (1): 49–60. doi:10.1016/S0960-0760(01)00174-1. PMID 11867263. http://linkinghub.elsevier.com/retrieve/pii/S0960076001001741. 20. ^ Towards Beautiful Eyes – Solutions for Thinning Lashes and Dark Patches, Kamau Austin. 21. ^ Frosch PJ, Pilz B, Andersen KE, et al. (November 1995). "Patch testing with fragrances: results of a multicenter study of the European Environmental and Contact Dermatitis Research Group with 48 frequently used constituents of perfumes". Contact Derm. 33 (5): 333–42. doi:10.1111/j.1600-0536.1995.tb02048.x. PMID 8565489. 22. ^ http://news.scotsman.com/latestnews/-Pseudo-science-can39t-cover.3606975.jp 23. ^ http://www.badscience.net/category/cosmetics/ 24. ^ http://www.cfsan.fda.gov/~dms/cos-206.html 25. ^ Singer, Natasha. "Natural, Organic Beauty." New York Times. 1 Nov. 2007. 18 Mar. 2008 26. ^ <http://www.nytimes.com/2007/11/01/fashion/01skin.html?_r=1&oref=slogin> 27. ^ a b "Cosmetic Industry". http://www.german-business-portal.info/GBP/Navigation/en/Business-Location/Manufacturing%20Industries/cosmetics-industry,did=326082.html. Retrieved 2010-08-04. 28. ^ "Blueprint for a Cosmetics Empire". http://www.japaninc.com/article.php?articleID=1390. Retrieved 2010-08-04. 29. ^ "France continues to lead the way in cosmetics". http://www.clickpress.com/releases/Detailed/82987005cp.shtml. Retrieved 2010-08-04. 30. ^ "Cosmetics - Europe (Italy) 2008 Marketing Research". http://researchwikis.com/Cosmetics_-_Europe_%28Italy%29_2008_Marketing_Research. Retrieved 2010-08-04. 31. ^ "Regulatory context". http://ec.europa.eu/consumers/sectors/cosmetics/animal-testing/index_en.htm. Retrieved 2010-08-04. 32. ^ "Animal Testing". http://www.fda.gov/Cosmetics/ProductandIngredientSafety/ProductTesting/ucm072268.htm. Retrieved 2010-08-04. 33. ^ "Buy Cosmetics Online". http://www.cosmeticindustry.org/buy.html. Retrieved 2010-08-04. [edit] Further reading Wikimedia Commons has media related to: Cosmetics * Winter, Ruth (2005) [2005] (in English). A Consumer's Dictionary of Cosmetic Ingredients: Complete Information About the Harmful and Desirable Ingredients in Cosmetics (Paperback). USA: Three Rivers Press. ISBN 1400052335. * Begoun, Paula (2003) [2003] (in English). Don't Go to the Cosmetics Counter Without Me(Paperback). USA: Beginning Press. ISBN 1877988308. * Carrasco, Francisco (2009) [2009] (in Spanish). Diccionario de Ingredientes Cosmeticos(Paperback). Spain: www.imagenpersonal.net. ISBN 9788461349791. [hide]v · d · eCosmetics Products Lips Lip gloss · Lip liner · Lip plumper · Lipstick Face Concealer · Foundation · Face powder · Rouge · Bindi · Thanaka · Tilaka · Cleanser-Toner-Moisturizer Eyes Eye liner · Eye shadow · Kohl · Mascara Other Shampoo-Conditioner-Styling cream · Nail polish · Anti-aging cream · Body powder · Cold cream · Sindoor Cosmetics.JPG Ingredients International Nomenclature of Cosmetic Ingredients · List of ingredients Related topics Cosmetic advertising · Beauty salon · Spa · Cosmetology · History of cosmetics Treatments Cosmetic surgery · Botox · Facial · Bleaching · Manicure · Pedicure · Hair removal (Waxing-Threading-Shaving) · Hair styling [show] Major brands Ahava · Almay · Artistry · Aveda · Avon · Bath & Body Works · Biotherm · Bobbi Brown · The Body Shop · Bonne Bell · Burt's Bees · Cargo · Carol's Daughter · Clarins · Clinique · CoverGirl · Creme 21 · Daigaku Honyaku Center · Dr. Hauschka · Eden Allure · Elizabeth Arden · Estée Lauder · Fabergé · Hard Candy · Helena Rubinstein · Kanebo Ltd. · Kao Corporation · Kevyn Aucoin · Kiehl's · La Mer · Lancôme · Laneige · Laura Mercier · Laura Mercier Cosmetics · Lise Watier · L'Oréal · L'occitane · Lush · MAC Cosmetics · Mary Kay · Max Factor · Maybelline · ModelCo · NARS · Natura · Natural Wonder · Neal's Yard Remedies · Neutrogena · Nexxus · Nivea · O Boticário · Oriflame · Origins · Paula Begoun · Red Earth · Revlon · Richard Hudnut · Rimmel · Sephora · Shiseido · Shu Uemura · SK-II · Stila · Ulta · Ultima II · Urban Decay · Vichy · Victoria's Secret · Vie at Home · Wella · Yves Rocher Categories Companies · People · History Retrieved from "http://en.wikipedia.org/wiki/Cosmetics" Categories: Cosmetics | Skin care | Greek loanwords Hidden categories: All articles with unsourced statements | Articles with unsourced statements from November 2007 | Articles with unsourced statements from September 2008 | Articles with unsourced statements from August 2008 Personal tools * Log in / create account Namespaces * Article * Discussion Variants Views * Read * Edit * View history Actions Search Search Navigation * Main page * Contents * Featured content * Current events * Random article * Donate to Wikipedia Interaction * Help * About Wikipedia * Community portal * Recent changes * Contact Wikipedia Toolbox * What links here * Related changes * Upload file * Special pages * Permanent link * Cite this page Print/export * Create a book * Download as PDF * Printable version Languages * العربية * Български * Català * Česky * Dansk * Deitsch * Deutsch * Español * Esperanto * Euskara * فارسی * Français * Gaeilge * ગુજરાતી * 한국어 * हिन्दी * Hrvatski * Bahasa Indonesia * Italiano * עברית * ಕನ್ನಡ * Latina * Lietuvių * Македонски * മലയാളം * Nederlands * 日本語 * ‪Norsk (bokmål)‬ * Олык Марий * Polski * Português * Română * Русский * Simple English * Српски / Srpski * Suomi * Svenska * Tagalog * தமிழ் * ไทย * Türkçe * Українська * اردو * 中文 * This page was last modified on 24 January 2011 at 13:59. * Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. 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  • Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and gels, deodorants, hand sanitizer, baby products, bath oils, bubble baths, bath salts, butters and many other types of products. A subset of cosmetics is called "make-up," which refers primarily to colored products intended to alter the user’s appearance. Many manufacturers distinguish between decorative cosmetics and care cosmetics. The manufacture of cosmetics is currently dominated by a small number of multinational corporations that originated in the early 20th century, but the distribution and sale of cosmetics is spread among a wide range of different businesses. The U.S. Food and Drug Administration (FDA) which regulates cosmetics in the United States[1] defines cosmetics as: "intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions." This broad definition includes, as well, any material intended for use as a component of a cosmetic product. The FDA specifically excludes soap from this category.[2] Contents [hide] * 1 History * 2 Criticism and controversy * 3 Makeup types * 4 Skin Care Products * 5 Ingredients o 5.1 Organic and natural ingredients * 6 Cosmetic industry * 7 Cosmetic careers * 8 See also * 9 References * 10 Further reading [edit] History Nefertiti bust with eye liner applied Main article: History of cosmetics The first archaeological evidence of cosmetics usage was found in Egypt around 3500 BC during the Ancient Egypt times with some of royalty owning make-up, such as Nefertiti, Nefertari, mask of Tutankhamun, etc. The Ancient Greeks and Romans[citation needed] also used cosmetics. The Romans and Ancient Egyptians used cosmetics containing poisonous mercury and often lead. The ancient kingdom of Israel was influenced by cosmetics as recorded in the Old Testament—2 Kings 9:30 where Jezebel painted her eyelids—approximately 840 BC. The Biblical book of Esther describes various beauty treatments as well. In the Middle Ages, although its use was frowned upon by Church leaders, many women still wore cosmetics. A popular fad for women during the Middle Ages was to have a pale-skinned complexion, which was achieved through either applying pastes of lead, chalk, or flour, or by bloodletting. Women would also put white lead pigment that was known as "ceruse" on their faces to appear to have pale skin.[3] Cosmetic use was frowned upon at many points in Western history. For example, in the 19th century, make-up was used primarily by prostitutes, and Queen Victoria publicly declared makeup improper, vulgar, and acceptable only for use by actors.[4] Adolf Hitler told women that face painting was for clowns and not for the women of the master race.[citation needed] Women in the 19th century liked to be thought of as fragile ladies. They compared themselves to delicate flowers and emphasised their delicacy and femininity. They aimed always to look pale and interesting. Sometimes ladies discreetly used a little rouge on the cheeks, and used "belladonna" to dilate their eyes to make their eyes stand out more. Make-up was frowned upon in general especially during the 1870s when social etiquette became more rigid. Actresses however were allowed to use make up and famous beauties such as Sarah Bernhardt and Lillie Langtry could be powdered. Most cosmetic products available were still either chemically dubious, or found in the kitchen amid food colorings, berries and beetroot. By the middle of the 20th century, cosmetics were in widespread use by women in nearly all industrial societies around the world. Cosmetics have been in use for thousands of years. The absence of regulation of the manufacture and use of cosmetics has led to negative side effects, deformities, blindness, and even death through the ages. Examples of this were the prevalent use of ceruse (white lead), to cover the face during the Renaissance, and blindness caused by the mascara Lash Lure during the early 20th century. The worldwide annual expenditures for cosmetics today is estimated at $19 billion.[5] Of the major firms, the largest is L'Oréal, which was founded by Eugene Schueller in 1909 as the French Harmless Hair Colouring Company (now owned by Liliane Bettencourt 26% and Nestlé 28%; the remaining 46% is traded publicly). The market was developed in the USA during the 1910s by Elizabeth Arden, Helena Rubinstein, and Max Factor. These firms were joined by Revlon just before World War II and Estée Lauder just after. Beauty products are now widely available from dedicated internet-only retailers,[6] who have more recently been joined online by established outlets, including the major department stores and traditional bricks and mortar beauty retailers. Like most industries, cosmetic companies resist regulation by government agencies like the FDA, and have lobbied against this throughout the years. The FDA does not have to approve or review the cosmetics, or what goes in them before they are sold to the consumers. The FDA only regulates against the colors that can be used in the cosmetics and hair dyes. The cosmetic companies do not have to report any injuries from the products; they also only have voluntary recalls on products.[7] [edit] Criticism and controversy Further information: Campaign for Safe Cosmetics and Testing cosmetics on animals During the 20th century, the popularity of cosmetics has increased rapidly.[citation needed] Cosmetics are used by girls at an increasingly young age, especially in the United States. Due to the fast-decreasing age of make-up users, many companies, from high-street brands like Rimmel to higher-end products like Estee Lauder, have catered to this expanding market by introducing more flavored lipsticks and glosses, cosmetics packaged in glittery, sparkly packaging and marketing and advertising using young models.[citation needed] The social consequences of younger and younger beautification has had much attention in the media over the last few years. Criticism of cosmetics has come from a variety of sources including some feminists, Islamists, Christianists, animal rights activists, authors and public interest groups. There is a growing awareness and preference for cosmetics that are without any supposedly toxic ingredients, especially those derived from petroleum, sodium lauryl sulfate (SLS), and parabens.[8] Numerous published reports have raised concern over the safety of a few surfactants. SLS causes a number of skin issues including dermatitis.[9][10][11][12][13] Parabens can cause skin irritation and contact dermatitis in individuals with paraben allergies, a small percentage of the general population.[14] Animal experiments have shown that parabens have a weak estrogenic activity, acting as xenoestrogens.[15] Prolonged use of makeup has also been linked to thinning eyelashes.[16] Synthetic fragrances are widely used in consumer products. Studies concluded from patch testing show synthetic fragrances are made of many ingredients which cause allergic reactions.[17] Cosmetics companies have been criticised for making pseudoscientific claims about their products which are misleading or unsupported by scientific evidence.[18][19] [edit] Makeup types * Lipstick, lip gloss, lip liner, lip plumper, lip balm, lip conditioner, lip primer, and lip boosters.[1] * Foundation, used to smooth out the face and cover spots or uneven skin coloration. Usually a liquid, cream, or powder.[1] Foundation primer can be applied before to get a smoother finish. * Powder, used to set the foundation, giving a matte finish, and also to conceal small flaws or blemishes. * Rouge, blush or blusher, cheek coloring used to bring out the color in the cheeks and make the cheekbones appear more defined. This comes in powder, cream, and liquid forms.[1] * Bronzer, used to give skin a bit of color by adding a golden or bronze glow.[1] * Mascara is used to darken, lengthen, and thicken the eyelashes. It is available in natural colors such as brown and black, but also comes in bolder colors such as blue, pink, or purple. There are many different formulas, including waterproof for those prone to allergies or sudden tears. Often used after an eyelash curler and mascara primer.[1] Eye shadow being applied Broadway actor Jim Brochu applies make-up before the opening night of a play. The chin mask known as chutti for Kathakali, a performing art in Kerala, India is considered the thickest makeup applied for any artform. * Eyelid glue, eye liner, eye shadow, eye shimmer, and glitter eye pencils as well as different color pencils used to color and emphasize the eyelids (larger eyes give a more youthful appearance).[1] * Eyebrow pencils, creams, waxes, gels and powders are used to color and define the brows.[1] * Nail polish, used to color the fingernails and toenails.[1] * Concealer, Makeup used to cover any imperfections of the skin. Cosmetics can also be described by the form of the product, as well as the area for application. Cosmetics can be liquid or cream emulsions; powders, both pressed and loose; dispersions; and anhydrous creams or sticks. Lip stain is a cosmetic product that contains either water or a gel base. To help the product stay on the lips, many stains may contain alcohol. These lip coloring products are available in a variety of formulas, colors, and application types. The idea behind lip stains is to temporarily saturate the lips with color with a dye, rather than applying a colored wax to the lips to color them. A lip stain is usually designed to be waterproof so that the color will be long lasting, and once the stain dries, it should not smear, stain, wear unevenly, or transfer to the teeth. A lip stain may come in a bottle with an applicator which is used to brush the stain onto the lips, and it can also come in a small jar, with users applying the stain with a finger or a cosmetic brush. Make-up remover is the product used to remove the make-up products applied on the skin. It is used for cleaning the skin for other procedures, like applying any type of lotion at evening before the person go to sleep. [edit] Skin Care Products Also included in the general category of cosmetics are skin care products. These include creams and lotions to moisturize the face and body which are often formulated for different skin types per range, sunscreens to protect the skin from UV radiation and damage, skin lighteners for a whiter skin, and treatment products to repair or hide skin imperfections (acne, wrinkles, dark circles under eyes, etc.), tanning oils to brown the skin. [edit] Ingredients Main article: Ingredients of cosmetics While there is assurance from the largest cosmetic companies that ingredients have passed quality tests and official regulations, and are therefore generally safe to use, there is a growing preference for cosmetics that are without any "synthetic" ingredients, especially those derived from petroleum. Once a niche market, handmade and certified organic products are becoming more mainstream. Ingredients' listings in cosmetics are highly regulated in many countries. The testing of cosmetic products on animals is a subject of some controversy. It is now illegal in the United Kingdom, the Netherlands, and Belgium, and a ban across the European Union is due to come into effect in 2009. [edit] Organic and natural ingredients Even though many cosmetic products are regulated, there are still health concerns regarding the presence of harmful chemicals within these products.[citation needed] Aside from color additives, cosmetic products and their ingredients are not subject to FDA regulation prior to their release into the market. It is only when a product is found to violate Federal Food, Drug, and Cosmetic Act (FD&C Act) and Fair Packaging and Labeling Act (FPLA) after its release that the FDA may start taking action against this violation.[20] With many new products released into the market every season, it is hard to keep track of the safety of every product. Some products carry carcinogenic contaminant 1,4- dioxane. Many cosmetic companies are coming out with "All natural" and organic products. All natural products contain mineral and plant ingredients and organic products are made with organic agricultural products. Products who claim they are organic are not, unless they are certified "USDA Organic."[21][22] See also: natural skin care [edit] Cosmetic industry The cosmetic industry is a profitable business for most manufacturers of cosmetic products. By cosmetic products, we understand anything that is intended for personal care such as skin lotions or sun lotions, makeup and other such products meant to emphasize one's look. Given the technological development and the improvement of the manufacturing process of cosmetics and not least due to the constantly increasing demand of such products, this industry reported an important growth in terms of profit. The cosmetic industry has not only grown only in the United States, but also in various parts of the world which have become famous for their cosmetic precuts. Some of these include France, Germany, Italy and Japan. It has been estimated that in Germany, the cosmetic industry generated sales of EUR 12.6 billion at retail sales, in 2008 [23] which made of German cosmetic industry the 3rd in the world, after Japan and the United States. Also, it has been shown that in the same country, this industry has grown with nearly 5 percent in one year, from 2007 to 2008. The exports of Germany in this industry reached in 2008 EUR 5.8 billion whereas the imports of cosmetics totaled EUR 3 billion.[23] The main countries that export cosmetics to Germany are France, Switzerland, the United States and Italy and they mainly consist of makeup and fragrances or perfumes for women. After the United States, Japan is the second largest market for cosmetics in the world, a market worth about JPY 1.4 trillion per year.[24] The worldwide cosmetics and perfume industry currently generates an estimated annual turnover of US$170 billion (according to Eurostaf - May 2007). Europe is the leading market, representing approximately €63 billion, while sales in France reached €6.5 billion in 2006, according to FIPAR (Fédération des Industries de la Parfumerie - the French federation for the perfume industry).[25] France is another country in which the cosmetic industry plays an important role, both nationally and internationally. Most products on whose label it is stated "Made in France" are valued on the international market. According to data from 2008, the cosmetic industry has risen constantly in France, for 40 consecutive years. In 2006, this industrial sector reached a record level of EUR 6.5 billion. Famous cosmetic brands produced in France include Vichy, Yves Saint Laurent, Yves Rocher and many others. The Italian cosmetic industry is also an important player in the European cosmetic market. Although not as large as in other European countries, the cosmetic industry in Italy was estimated to reach EUR 9 billion in 2007.[26] The Italian cosmetic industry is however dominated by hair and body products and not makeup as in many other European countries. In Italy, hair and body products make up approximately 30% of the cosmetic market. Makeup and facial care however are the first cosmetic products to be exported in the United States. Due to the popularity of cosmetics, especially fragrances and perfumes, many designers who are not necessarily involved in the cosmetic industry came up with different perfumes carrying their names. Moreover, most actors and singers also have their own perfume line (such as Celine Dion). The designer perfumes are, like any other designer products, the most expensive in the industry as the consumer pays not only for the product but also for the brand. Famous Italian fragrances are produced by Giorgio Armani, Dolce and Gabbana and so on. The European Commission and the FDA are the two bodies making legislation in what concerns cosmetic industry and its various aspects within the European Union, respectively in the United States. In the European Union, the circulation of cosmetic products and their safety are law subjects since 1976. One of the newest amendments of the directive concerning cosmetic industry comes as a result of the attempt to ban animal testing. Therefore, testing cosmetic products on animals is illegal in the European Union from September 2004 and testing separate ingredients of such products on animals is also prohibited by law starting with March 2009.[27] The FDA joined with thirteen other Federal agencies in forming the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) in 1997 which is an attempt to ban animal testing and find other methods to test the cosmetic products.[28] The cosmetic industry worldwide seems to be continuously developing, now more than ever with the advent of the Internet companies. Many famous companies sell their cosmetic products online also in countries in which they do not have representatives.[29] [edit] Cosmetic careers A professional make-up artist servicing a client An account executive is responsible for visiting all department and specialty store counter sales and doors. They explain new products and "gifts with purchase" (free items given out upon purchase of a certain cosmetics item that costs more than a set amount). A beauty adviser provides product advice based on the client's skin care and makeup requirements. Beauty advisers can become certified through the Anti-Aging Beauty Institute. Supermodel Alek Wek receiving make-up from a professional. A cosmetician is a professional who provides facial and body treatments for clients. The term cosmetologist is sometimes used interchangeably with this term, but most commonly refers to a certified professional. A freelance makeup artist provides clients with beauty advice and cosmetics assistance—usually paid by the cosmetic company by the hour. Professionals in cosmetics marketing careers manage research focus groups, promote the desired brand image, and provide other marketing services (sales forecasting, allocation to different retailers, etc.). Those involved in cosmetics product development design, create and refine cosmetics products. Some positions that fall under this category include chemists, quality assurance and packaging people. Many involved within the cosmetics industry often specialize in a certain area of cosmetics such as special effects makeup or makeup techniques specific to the film, media and fashion sectors.
  • eye Return to the top
  • Eyes are organs that detect light, and convert it to electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement. In higher organisms the eye is a complex optical system which collects light from the surrounding environment; regulates its intensity through a diaphragm; focuses it through an adjustable assembly of lenses to form an image; converts this image into a set of electrical signals; and transmits these signals to the brain, through complex neural pathways that connect the eye, via the optic nerve, to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system.[1] Image-resolving eyes are present in molluscs, chordates and arthropods.[2] The simplest "eyes", such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment. Contents [hide] * 1 Overview * 2 Evolution * 3 Types of eye o 3.1 Non-compound eyes + 3.1.1 Pit eyes + 3.1.2 Spherical lensed eye + 3.1.3 Multiple lenses + 3.1.4 Refractive cornea + 3.1.5 Reflector eyes o 3.2 Compound eyes + 3.2.1 Apposition eyes + 3.2.2 Superposition eyes + 3.2.3 Parabolic superposition + 3.2.4 Other + 3.2.5 Nutrients of the eye * 4 Relationship to life requirements * 5 Visual acuity * 6 Perception of colours * 7 Rods and cones * 8 Pigmentation * 9 See also * 10 References o 10.1 Notes o 10.2 Bibliography * 11 External links [edit] Overview Eye of the wisent, the European bison Complex eyes can distinguish shapes and colours. The visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception; in other organisms, eyes are located so as to maximize the field of view, such as in rabbits and horses, which have monocular vision. The first proto-eyes evolved among animals 600 million years ago, about the time of the Cambrian explosion.[3] The last common ancestor of animals possessed the biochemical toolkit necessary for vision, and more advanced eyes have evolved in 96% of animal species in six of the thirty-plus[4] main phyla.[1] In most vertebrates and some molluscs, the eye works by allowing light to enter and project onto a light-sensitive panel of cells, known as the retina, at the rear of the eye. The cone cells (for colour) and the rod cells (for low-light contrasts) in the retina detect and convert light into neural signals for vision. The visual signals are then transmitted to the brain via the optic nerve. Such eyes are typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing lens and often an iris; the relaxing or tightening of the muscles around the iris change the size of the pupil, thereby regulating the amount of light that enters the eye,[5] and reducing aberrations when there is enough light.[6] The eyes of most cephalopods, fish, amphibians and snakes have fixed lens shapes, and focusing vision is achieved by telescoping the lens—similar to how a camera focuses.[7] Compound eyes are found among the arthropods and are composed of many simple facets which, depending on the details of anatomy, may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cell(s). Some eyes have up to 28,000 such sensors, which are arranged hexagonally, and which can give a full 360-degree field of vision. Compound eyes are very sensitive to motion. Some arthropods, including many Strepsiptera, have compound eyes of only a few facets, each with a retina capable of creating an image, creating vision. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high-resolution images. Possessing detailed hyperspectral colour vision, the Mantis shrimp has been reported to have the world's most complex colour vision system.[8] Trilobites, which are now extinct, had unique compound eyes. They used clear calcite crystals to form the lenses of their eyes. In this, they differ from most other arthropods, which have soft eyes. The number of lenses in such an eye varied, however: some trilobites had only one, and some had thousands of lenses in one eye. In contrast to compound eyes, simple eyes are those that have a single lens. For example, jumping spiders have a large pair of simple eyes with a narrow field of view, supported by an array of other, smaller eyes for peripheral vision. Some insect larvae, like caterpillars, have a different type of simple eye (stemmata) which gives a rough image. Some of the simplest eyes, called ocelli, can be found in animals like some of the snails, which cannot actually "see" in the normal sense. They do have photosensitive cells, but no lens and no other means of projecting an image onto these cells. They can distinguish between light and dark, but no more. This enables snails to keep out of direct sunlight. In organisms dwelling near deep-sea vents, compound eyes have been secondarily simplified and adapted to spot the infra-red light produced by the hot vents–in this way the bearers can spot hot springs and avoid being boiled alive.[9] [edit] Evolution Main article: Evolution of the eye Evolution of the eye Photoreception is phylogenetically very old, with various theories of phylogenesis.[10] The common origin (monophyly) of all animal eyes is now widely accepted as fact. This is based upon the shared anatomical and genetic features of all eyes; that is, all modern eyes, varied as they are, have their origins in a proto-eye believed to have evolved some 540 million years ago.[11][12][13] The majority of the advancements in early eyes are believed to have taken only a few million years to develop, since the first predator to gain true imaging would have touched off an "arms race".[14] Prey animals and competing predators alike would be at a distinct disadvantage without such capabilities and would be less likely to survive and reproduce. Hence multiple eye types and subtypes developed in parallel. Eyes in various animals show adaption to their requirements. For example, birds of prey have much greater visual acuity than humans, and some can see ultraviolet light. The different forms of eye in, for example, vertebrates and mollusks are often cited as examples of parallel evolution, despite their distant common ancestry. The very earliest "eyes", called eyespots, were simple patches of photoreceptor protein in unicellular animals. In multicellular beings, multicellular eyespots evolved, physically similar to the receptor patches for taste and smell. These eyespots could only sense ambient brightness: they could distinguish light and dark, but not the direction of the lightsource.[15] Through gradual change, as the eyespot depressed into a shallow "cup" shape, the ability to slightly discriminate directional brightness was achieved by using the angle at which the light hit certain cells to identify the source. The pit deepened over time, the opening diminished in size, and the number of photoreceptor cells increased, forming an effective pinhole camera that was capable of dimly distinguishing shapes.[16] The thin overgrowth of transparent cells over the eye's aperture, originally formed to prevent damage to the eyespot, allowed the segregated contents of the eye chamber to specialize into a transparent humour that optimized color filtering, blocked harmful radiation, improved the eye's refractive index, and allowed functionality outside of water. The transparent protective cells eventually split into two layers, with circulatory fluid in between that allowed wider viewing angles and greater imaging resolution, and the thickness of the transparent layer gradually increased, in most species with the transparent crystallin protein.[17] The gap between tissue layers naturally formed a bioconvex shape, an optimally ideal structure for a normal refractive index. Independently, a transparent layer and a nontransparent layer split forward from the lens: the cornea and iris. Separation of the forward layer again formed a humour, the aqueous humour. This increased refractive power and again eased circulatory problems. Formation of a nontransparent ring allowed more blood vessels, more circulation, and larger eye sizes.[17] [edit] Types of eye There are ten different eye layouts—indeed every way of capturing an optical image commonly used by man, with the exceptions of zoom and Fresnel lenses. Eye types can be categorized into "simple eyes", with one concave photoreceptive surface, and "compound eyes", which comprise a number of individual lenses laid out on a convex surface.[1] Note that "simple" does not imply a reduced level of complexity or acuity. Indeed, any eye type can be adapted for almost any behaviour or environment. The only limitations specific to eye types are that of resolution—the physics of compound eyes prevents them from achieving a resolution better than 1°. Also, superposition eyes can achieve greater sensitivity than apposition eyes, so are better suited to dark-dwelling creatures.[1] Eyes also fall into two groups on the basis of their photoreceptor's cellular construction, with the photoreceptor cells either being cilliated (as in the vertebrates) or rhabdomeric. These two groups are not monophyletic; the cnidaria also possess cilliated cells, [18] and some annelids possess both.[19] [edit] Non-compound eyes Simple eyes are rather ubiquitous, and lens-bearing eyes have evolved at least seven times in vertebrates, cephalopods, annelids, crustacea and cubozoa.[20] [edit] Pit eyes Pit eyes, also known as stemma, are eye-spots which may be set into a pit to reduce the angles of light that enters and affects the eyespot, to allow the organism to deduce the angle of incoming light.[1] Found in about 85% of phyla, these basic forms were probably the precursors to more advanced types of "simple eye". They are small, comprising up to about 100 cells covering about 100 µm.[1] The directionality can be improved by reducing the size of the aperture, by incorporating a reflective layer behind the receptor cells, or by filling the pit with a refractile material.[1] Pit vipers have developed pits that function as eyes by sensing thermal infra-red radiation, in addition to their optical wavelength eyes like those of other vertebrates. [edit] Spherical lensed eye The resolution of pit eyes can be greatly improved by incorporating a material with a higher refractive index to form a lens, which may greatly reduce the blur radius encountered—hence increasing the resolution obtainable.[1] The most basic form, seen in some gastropods and annelids, consists of a lens of one refractive index. A far sharper image can be obtained using materials with a high refractive index, decreasing to the edges; this decreases the focal length and thus allows a sharp image to form on the retina.[1] This also allows a larger aperture for a given sharpness of image, allowing more light to enter the lens; and a flatter lens, reducing spherical aberration.[1] Such an inhomogeneous lens is necessary in order for the focal length to drop from about 4 times the lens radius, to 2.5 radii.[1] Heterogeneous eyes have evolved at least eight times: four or more times in gastropods, once in the copepods, once in the annelids and once in the cephalopods.[1] No aquatic organisms possess homogeneous lenses; presumably the evolutionary pressure for a heterogeneous lens is great enough for this stage to be quickly "outgrown".[1] This eye creates an image that is sharp enough that motion of the eye can cause significant blurring. To minimize the effect of eye motion while the animal moves, most such eyes have stabilizing eye muscles.[1] The ocelli of insects bear a simple lens, but their focal point always lies behind the retina; consequently they can never form a sharp image. This capitulates the function of the eye. Ocelli (pit-type eyes of arthropods) blur the image across the whole retina, and are consequently excellent at responding to rapid changes in light intensity across the whole visual field; this fast response is further accelerated by the large nerve bundles which rush the information to the brain.[21] Focusing the image would also cause the sun's image to be focused on a few receptors, with the possibility of damage under the intense light; shielding the receptors would block out some light and thus reduce their sensitivity.[21] This fast response has led to suggestions that the ocelli of insects are used mainly in flight, because they can be used to detect sudden changes in which way is up (because light, especially UV light which is absorbed by vegetation, usually comes from above).[21
  • pimple Return to the top
  • A pimple is a kind of acne, and one of the many results of excess oil clogging the pores. Some of the varieties are pustules or papules.[1] Pimples can be treated by various acne medications prescribed by a dermatologist, or purchased at a drug store with a wide variety of treatments. Listen to this article (info/dl) Play sound This audio file was created from a revision of Pimple dated 2010-04-26, and does not reflect subsequent edits to the article. (Audio help) More spoken articles Sound-icon.svg Contents [hide] * 1 Causes * 2 Treatment o 2.1 Over-the-counter medications o 2.2 Prescription medication * 3 See also * 4 References [edit] Causes a "whitehead" pimples can lead to significant swelling and may appear on the back and chest Blackheads -- sebum darkened by contact and reaction with air Inside the pore are sebaceous glands which produce sebum. When the outer layers of skin shed (as they do continuously), the dead skin cells left behind may become 'glued' together by the sebum. This causes the blockage in the pore, especially when the skin becomes thicker at puberty.[2] The sebaceous glands produce more sebum which builds up behind the blockage, and this sebum harbours various bacteria including the species Propionibacterium acnes, causing infection and inflammation. [edit] Treatment See also: Acne vulgaris#Treatments [edit] Over-the-counter medications Common over-the-counter medications for pimples are benzoyl peroxide and/or salicylic acid and antibacterial agents such as Triclosan. Both medications can be found in many creams and gels used to treat acne [acne vulgaris] through topical application. Both medications help skin slough off more easily, which helps to remove bacteria faster. Acne Rosacea is not caused by bacterial infection. It is commonly treated with tretinoin. A regimen of keeping the affected skin area clean plus the regular application of these topical medications is usually enough to keep acne under control, if not at bay altogether. 1-2% of the population is allergic to benzoyl peroxide treatments.[citation needed]. Recently nicotinamide, applied topically, has been shown to be more effective in treatment of pimples than antibiotics such as clindamycin.[citation needed] Nicotinamide (vitamin B3) is not an antibiotic and has no side-effects typically associated with antibiotics. It has the added advantage of reducing skin hyperpigmentation which results in pimple scars.[citation needed] [edit] Prescription medication Severe acne usually indicates the necessity of prescription medication to treat the pimples. Prescription medications used to treat acne [3] and pimples include isotretinoin, which is a retinoid. Historically, antibiotics such as tetracyclines and erythromycin were prescribed. While they were more effective than topical applications of benzoyl peroxide, the bacteria eventually grew resistant to the antibiotics and the treatments became less and less effective. Also, antibiotics had more side effects than topical applications, such as stomach cramps and severe discoloration of teeth.
  • anti aging Return to the top
  • an·ti·ag·ing    /ˌæntiˈeɪdʒɪŋ, ˌæntaɪ-/ Show Spelled[an-tee-ey-jing, an-tahy-] Show IPA –adjective effective in retarding the effects of aging: Chemists hope to produce an antiaging drug. Use anti-aging in a Sentence See images of anti-aging Search anti-aging on the Web Also, an·ti·age·ing. Origin: anti- + age (v.) + -ing1 Dictionary.com Unabridged Based on the Random House Dictionary, © Random House, Inc. 2011. Cite This Source | Link To anti-aging Medical Dictionary an·ti·ag·ing definition Pronunciation: /-ˈāj-iŋ/ Function: adj : used or tending to prevent or lessen the effects of aging < antiaging skin creams> Merriam-Webster's Medical Dictionary, © 2007 Merriam-Webster, Inc. Cite This Source Famous Quotations antiaging "It is important to note that multiculturalism does not ..." "So that the old joy, modest as cake, as wine and friend..." "Christ, what a planet!" "Good Americans, when they die, go to Paris." "A little instruction in the elements of chartography—a ..."
  • Life extension, also known as anti-aging medicine, experimental gerontology, and biomedical gerontology, refers to attempts to slow down or reverse[clarification needed] the processes of aging to extend both the maximum and average lifespan. Some researchers in this area, and "life extensionists" or "longevists" (who wish to achieve longer lives for themselves), believe that future breakthroughs in tissue rejuvenation with stem cells, molecular repair, and organ replacement (such as with artificial organs or xenotransplantations) will eventually enable humans to have indefinite lifespans through complete rejuvenation to a youthful condition. The sale of putative anti-aging products such as nutrition, physical fitness, skin care, hormone replacements, vitamins, supplements and herbs is a lucrative global industry, with the US market generating about $50 billion of revenue each year.[1] Medical experts state that the use of such products has not been shown to affect the aging process, and many claims of anti-aging medicine advocates have been roundly criticized by medical experts, including the American Medical Association.[1][2][3][4][5] Bioethicists question whether and how the human lifespan should be extended. Contents [hide] * 1 Average and maximum lifespans * 2 Current anti-aging strategies and issues o 2.1 Diets and supplements o 2.2 Hormone treatments o 2.3 Scientific controversy regarding anti-aging nutritional supplementation and medicine o 2.4 Ethics and politics of anti-aging nutritional supplementation and medicine * 3 Proposed strategies of life extension o 3.1 Nanotechnology o 3.2 Cloning and body part replacement o 3.3 Cryonics o 3.4 Theoretical combination strategies o 3.5 Genetic modification * 4 History of life extension and the life extension movement * 5 Ethics and politics of life extension * 6 See also * 7 References * 8 Further reading o 8.1 Books o 8.2 Scientific journals * 9 External links [edit] Average and maximum lifespans Main article: Senescence During the process of aging, an organism accumulates damage to macromolecules, its cells, its tissues and its organs. The maximum life span for humans is in excess of 120 years, whereas the maximum lifespan of a mouse, commonly used as a model in research on aging, is about four years. Genetic differences between humans and mice that may account for these different aging rates include efficiency of DNA repair, types and quantities of antioxidant enzymes, and different rates of free radical production. Average lifespan in a population is lowered by infant and child mortality, which are frequently linked to infectious diseases or nutrition problems. Later in life, vulnerability to accidents and age-related chronic disease such as cancer or cardiovascular disease play an increasing role in mortality. Extension of expected lifespan can often be achieved by good diet, exercise and avoidance of hazards such as smoking. Maximum lifespan is determined by the rate of aging for a species inherent in its genes and by environmental factors. One widely recognized method of extending maximum lifespan in organisms such as nematodes is calorie restriction. Another technique used evolutionary pressure such as breeding from only older members. Theoretically, extension of maximum lifespan could be achieved by reducing the rate of aging damage, by periodic replacement of damaged tissues, or by molecular repair or rejuvenation of deteriorated cells and tissues. [edit] Current anti-aging strategies and issues [edit] Diets and supplements Much life extension research focuses on nutrition—diets or supplements—as a means to extend lifespan, although few of these have been systematically tested for significant longevity effects. The many diets promoted by anti-aging advocates are often contradictory. Two diets with different approaches and some support from scientific research are the Paleolithic diet and Caloric restriction.[6][7][8][9] The free-radical theory of aging suggests that antioxidant supplements, such as Vitamin C, Vitamin E, Q10, lipoic acid, carnosine, and N-acetylcysteine, might extend human life.[further explanation needed] However, combined evidence from several clinical trials suggest that β-Carotene supplements and high doses of Vitamin E increase mortality rates.[specify][10] Other substances proposed to extend lifespan include oxytocin, insulin, human chorionic gonadotropin (hCG), and erythropoietin (EPO). Resveratrol is a sirtuin stimulant that appears to extend lifespan in simple organisms such as nematodes[11] and short-lived fish.[12] Some supplements, including the minerals selenium[13] or zinc[14][15] have been reported to extend the lifespan of rats and mice, though none has been proven to do so in humans, and significant toxic effects were observed.[which?] Metformin[16] may also extend life span in mice. [edit] Hormone treatments The anti-aging industry offers several hormone therapies. Some of these have been criticized for possible dangers to the patient and a lack of proven effect. For example, the American Medical Association has been critical of some anti-aging hormone therapies.[1] The evidence for use of growth hormone as an anti-aging therapy is mixed and based on animal studies. An early study suggested that supplementation of mice with growth hormone increased average life expectancy.[17] Additional animal experiments have suggested that growth hormone may generally act to shorten maximum lifespan; knockout mice lacking the receptor for growth hormone live especially long.[18] Furthermore, mouse models lacking the insulin-like growth factor also live especially long and have low levels of growth hormone.[18] [edit] Scientific controversy regarding anti-aging nutritional supplementation and medicine Some critics dispute the portrayal of aging as a disease. For example, Leonard Hayflick, who determined that fibroblasts are limited to around 50 cell divisions,[further explanation needed] reasons that aging is an unavoidable consequence of entropy. Hayflick and fellow biogerontologists Jay Olshansky and Bruce Carnes have strongly criticized the anti-aging industry in response to what they see as unscrupulous profiteering from the sale of unproven anti-aging supplements.[3] [edit] Ethics and politics of anti-aging nutritional supplementation and medicine Politics relevant to the substances of life extension pertain mostly to communications and availability.[according to whom?][citation needed] In the United States, product claims on food and drug labels are strictly regulated. The First Amendment (freedom of speech) protects third-party publishers' rights to distribute fact, opinion and speculation on life extension practices. Manufacturers and suppliers also provide informational publications, but because they market the substances, they are subject to monitoring and enforcement by the Federal Trade Commission (FTC), which polices claims by marketers. What constitutes the difference between truthful and false claims is hotly debated and is a central controversy in this arena.[citation needed] [edit] Proposed strategies of life extension [edit] Nanotechnology Future advances in nanomedicine could give rise to life extension through the repair of many processes thought to be responsible for aging. Raymond Kurzweil, a futurist and transhumanist, believes that advanced medical nanorobotics could completely remedy the effects of aging by 2030.[19] [edit] Cloning and body part replacement Some life extensionists suggest that therapeutic cloning and stem cell research could one day provide a way to generate cells, body parts, or even entire bodies (generally referred to as reproductive cloning) that would be genetically identical to a prospective patient. In one experiment, a functioning dog's bladder was grown and proved to be viable after implantation.[citation needed] Recently, the US Department of Defense initiated a program to research the possibility of growing human body parts on mice.[20] Complex biological structures, such as mammalian joints and limbs, have not yet been replicated. Dog and primate brain transplantation experiments were conducted in the mid-20th century but failed due to rejection and the inability to restore nerve connections. Proponents of body part replacement and cloning contend that the required biotechnologies are likely to appear earlier than other life-extension technologies. The use of human stem cells, particularly embryonic stem cells, is controversial. Opponents' objections generally are based on interpretations of religious teachings or ethical considerations.[according to whom?] Proponents[who?] of stem cell research point out that cells are routinely formed and destroyed in a variety of contexts. Use of stem cells taken from the umbilical cord or parts of the adult body may not provoke controversy.[21] The controversies over cloning are similar, except general public opinion in most countries stands in opposition to reproductive cloning. Some proponents[who?] of therapeutic cloning predict the production of whole bodies, lacking consciousness, for eventual brain transplantation. [edit] Cryonics Main article: Cryonics For cryonicists (advocates of cryopreservation), storing the body at low temperatures after death may provide an "ambulance" into a future in which advanced medical technologies may allow resuscitation and repair. They speculate cryogenic temperatures will minimize changes in biological tissue for many years, giving the medical community ample time to cure all disease, rejuvenate the aged and repair any damage that is caused by the cryopreservation process. Cryonicists do not believe that legal death is "real death" because stoppage of heartbeat and breathing—the usual medical criteria for legal death—occur before biological death of cells and tissues of the body. Even at room temperature, cells may take hours to die and days to decompose. Although neurological damage occurs within 4–6 minutes of cardiac arrest, the irreversible neurodegenerative processes do not manifest for hours.[22] Cryonicists state that rapid cooling and cardio-pulmonary support applied immediately after certification of death can preserve cells and tissues for long-term preservation at cryogenic temperatures. People, particularly children, have survived up to an hour without heartbeat after submersion in ice water. In one case, full recovery was reported after 45 minutes underwater.[23] To facilitate rapid preservation of cells and tissue, cryonics "standby teams" are available to wait by the bedside of patients who are to be cryopreserved to apply cooling and cardio-pulmonary support as soon as possible after declaration of death.[24] No mammal has been successfully cryopreserved and brought back to life, and cryonics is not currently accepted as viable by science.[clarification needed] Some individual scientists support the idea based on their expectations of the capabilities of future science.[25][26] [edit] Theoretical combination strategies Main article: Strategies for Engineered Negligible Senescence Another proposed life extension technology would combine existing and predicted future biochemical and genetic techniques. One such theoretical strategy proposes a cure for cancer, stem cell treatments, addition of new enzymes to the human body and moving mitochondrial DNA to the cellular nucleus.[27] This proposal is said to lack scientific evidence[4] and has been called pseudoscientific because its proposed techniques are speculative.[2] [edit] Genetic modification Gene therapy, in which artificial genes are integrated with an organism to replace mutated or otherwise deficient genes, has been proposed as a future strategy to prevent aging.[28][29] Targeting catalase to the mitochondria resulted in a 20% lifespan increase in transgenic mice, and improved performance in AAV[clarification needed] therapeutically infected mice.[30] [edit] History of life extension and the life extension movement In 1970, the American Aging Association was formed under the impetus of Denham Harman, originator of the free radical theory of aging. Harman wanted an organization of biogerontologists that was devoted to research and to the sharing of information among scientists interested in extending human lifespan. In 1976, futurists Joel Kurtzman and Philip Gordon wrote No More Dying. The Conquest Of Aging And The Extension Of Human Life, (ISBN 0-440-36247-4) the first popular book on research to extend human lifespan. Subsequently, Kurtzman was invited to testify before the House Select Committee on Aging, chaired by Claude Pepper of Florida, to discuss the impact of life extension on the Social Security system. Saul Kent published The Life Extension Revolution (ISBN 0-688-03580-9) in 1980 and created a nutraceutical firm called the Life Extension Foundation, a non-profit organization that promotes dietary supplements. The Life Extension Foundation publishes a periodical called Life Extension Magazine. The 1982 bestselling book Life Extension: A Practical Scientific Approach (ISBN 0-446-51229-X) by Durk Pearson and Sandy Shaw further popularized the phrase "life extension". In 1983, Roy Walford, a life-extensionist and gerontologist, published a popular book called Maximum Lifespan. In 1988, Walford and his student Richard Weindruch summarized their research into the ability of calorie restriction to extend the lifespan of rodents in The Retardation of Aging and Disease by Dietary Restriction (ISBN 0-398-05496-7). It had been known since the work of Clive McCay in the 1930s that calorie restriction can extend the maximum lifespan of rodents. But it was the work of Walford and Weindruch that gave detailed scientific grounding to that knowledge.[citation needed] Walford's personal interest in life extension motivated his scientific work and he practiced calorie restriction himself. Walford died at the age of 80 from complications caused by amyotrophic lateral sclerosis. Money generated by the non-profit Life Extension Foundation allowed Saul Kent to finance the Alcor Life Extension Foundation, the world's largest cryonics organization. The cryonics movement had been launched in 1962 by Robert Ettinger's book, The Prospect of Immortality. In the 1960s, Saul Kent had been a co-founder of the Cryonics Society of New York. Alcor gained national prominence when baseball star Ted Williams was cryonically preserved by Alcor in 2002 and a family dispute arose as to whether Williams had really wanted to be cryopreserved. Regulatory and legal struggles between the Food and Drug Administration (FDA) and the Life Extension Foundation included seizure of merchandise and court action. In 1991, Saul Kent and Bill Faloon, the principals of the Foundation, were jailed. The LEF accused the FDA of perpetrating a "Holocaust" and "seeking gestapo-like power" through its regulation of drugs and marketing claims.[31] In 1992, the American Academy of Anti-Aging Medicine (A4M) was formed to create what it considered an anti-aging medical specialty distinct from geriatrics, and to hold trade shows for physicians interested in anti-aging medicine. The American Board of Medical Specialties recognizes neither anti-aging medicine nor the A4M's professional standing.[32] [edit] Ethics and politics of life extension Leon Kass (chairman of the US President's Council on Bioethics from 2001 to 2005) has questioned whether potential exacerbation of overpopulation problems would make life extension unethical.[33] He states his opposition to life extension with the words: "simply to covet a prolonged life span for ourselves is both a sign and a cause of our failure to open ourselves to procreation and to any higher purpose ... [The] desire to prolong youthfulness is not only a childish desire to eat one's life and keep it; it is also an expression of a childish and narcissistic wish incompatible with devotion to posterity."[34] Transhumanist philosopher Nick Bostrom has argued that any technological advances in life extension must be equitably distributed and not restricted to a privileged few.[35] In an extended metaphor entitled "The Fable of the Dragon-Tyrant", Bostrom envisions death as a monstrous dragon who demands human sacrifices. In the fable, after a lengthy debate between those who believe the dragon is a fact of life and those who believe the dragon can and should be destroyed, the dragon is finally killed. Bostrom argues that political inaction allowed many preventable human deaths to occur.[36]
  • nose Return to the top
  • Physically a nose is an organ on the face. Anatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration in conjunction with the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes through the pharynx, shared with the digestive system, and then into the rest of the respiratory system. In humans, the nose is located centrally on the face; on most other mammals, it is on the upper tip of the snout. Contents [hide] * 1 Air conditioning * 2 Sense of direction * 3 Structure in air-breathing forms * 4 In fish * 5 See also * 6 References * 7 External links [edit] Air conditioning As an interface between the body and the external world, the nose and associated structures frequently perform additional functions concerned with conditioning entering air (for instance, by warming and/or humidifying it, also for flicking if moving and by mostly reclaiming moisture from the air before it is exhaled (as occurs most efficiently in camels). The nose often has inner hairs whose function is to stop unwanted particles from entering the lungs. [edit] Sense of direction The wet nose of dogs is useful for the perception of direction. The sensitive cold receptors in the skin detect the place where the nose is cooled the most and this is the direction a particular smell that the animal just picked up comes from.[1] [edit] Structure in air-breathing forms The nose of a tapir. In amphibians and lungfish, the nostrils open into small sacs that, in turn, open into the forward roof of the mouth through the choanae. These sacs contain a small amount of olfactory epithelium, which, in the case of caecilians, also lines a number of neighbouring tentacles. Despite the general similarity in structure to those of amphibians, the nostrils of lungfish are not used in respiration, since these animals breathe through their mouths. Amphibians also have a vomeronasal organ, lined by olfactory epithelium, but, unlike those of amniotes, this is generally a simple sac that, except in salamanders, has little connection with the rest of the nasal system.[2] In reptiles, the nasal chamber is generally larger, with the choanae being located much further back in the roof of the mouth. In crocodilians, the chamber is exceptionally long, helping the animal to breathe while partially submerged. The reptilian nasal chamber is divided into three parts: an anterior vestibule, the main olfactory chamber, and a posterior nasopharynx. The olfactory chamber is lined by olfactory epithelium on its upper surface and possesses a number of turbinates to increase the sensory area. The vomeronasal organ is well-developed in lizards and snakes, in which it no longer connects with the nasal cavity, opening directly into the roof of the mouth. It is smaller in turtles, in which it retains its original nasal connection, and is absent in adult crocodilians.[2] Birds have a similar nose to reptiles, with the nostrils being located at the upper rear part of the beak. Since they generally have a poor sense of smell, the olfactory chamber is small, although it does contain three turbinates, which sometimes have a complex structure similar to that of mammals. In many birds, including doves and fowls, the nostrils are covered by a horny protective shield. The vomeronasal organ of birds is either under-developed or altogether absent, depending on the species.[2] Elephants have prehensile noses. The nasal cavities are exceptionally large in most mammals, typically occupying up to half the length of the skull. In some groups, however, including primates, bats, and cetaceans, the nose has been secondarily reduced, and these animals consequently have a relatively poor sense of smell. The nasal cavity of mammals has been enlarged, in part, by the development of a palate cutting off the entire upper surface of the original oral cavity, which consequently becomes part of the nose, leaving the palate as the new roof of the mouth. The enlarged nasal cavity contains complex turbinates forming coiled scroll-like shapes that help to warm the air before it reaches the lungs. The cavity also extends into neighbouring skull bones, forming additional air cavities known as paranasal sinuses.[2] In cetaceans, the nose has been reduced to the nostrils, which have migrated to the top of the head, producing a more streamlined body shape and the ability to breathe while mostly submerged. Conversely, the elephant's nose has elaborated into a long, muscular, manipulative organ called the trunk. The vomeronasal organ of mammals is generally similar to that of reptiles. In most species, it is located in the floor of the nasal cavity, and opens into the mouth via two nasopalatine ducts running through the palate, but it opens directly into the nose in many rodents. It is, however, lost in bats, and in many primates, including humans.[2]
  • trimmer Return to the top
  • A trimmer or preset[1] is a miniature adjustable electrical component. It is meant to be set correctly when installed in some device, and never seen or adjusted by the device's user. Trimmers can be variable resistors (potentiometers), variable capacitors, trimmable inductors. They are common in precision circuitry like A/V components, and may need to be adjusted when the equipment is serviced. Unlike many other variable controls, trimmers are mounted directly on circuit boards, turned with a small screwdriver and rated for many fewer adjustments over their lifetime. Trimmers like trimmable inductors and trimmable capacitors are usually found in superhet radio and television receivers, in the Intermediate frequency, oscillator and RF circuits. They are adjusted into the right position during the alignment procedure of the receiver. Trimmers come in a variety of sizes and levels of precision; for example, multi-turn trim potentiometers exist, in which it takes several turns of the adjustment screw to reach the end value, allowing for very high degrees of accuracy. In 1952, Marlan Bourns patented the world's first trimming potentiometer, trademarked "Trimpot", a name now commonly used to refer to any trimming potentiometer.
  • nasal hair Return to the top
  • Nasal hair or nose hair is the hair in the nose. Its main function is to keep foreign or unwanted particles from entering the lungs through the nasal cavity. Adult humans have hairs in the anterior nasal passage. Nasal hair should not be confused with cilia of the nasal cavity, which are the microscopic cellular strands that, unlike macroscopic nasal hair, draws mucus up toward the oropharynx via their coordinated, back-and-forth beating. [edit] Removal A number of devices have been sold to trim the nose hair, including miniature rotary clippers, and attachments for electric shavers. The trimmers shorten the hair to such lengths so that they do not appear outside of the nasal passage. The removal of nasal hair by plucking can be painful, followed by a reaction of tearing eyes, sneezing and sometimes bleeding. These symptoms can be lessened if the plucking occurs in a situation where more warm moisture is present in the nasal passage (e.g. after a shower or steam facial); However, the pain associated with this method of nose hair removal can be a prohibitive factor to its removal for cosmetic purposes. Removal by hand can be less painful, though acquiring a firm grip on a single hair may prove prohibitively difficult for some. A pair of tweezers can be used which facilitates removal and an antiseptic cream applied after treatment on the end of a cotton-bud to reduce the risk of infection and soreness. Some sources suggest that removing nose hair by pulling can be extremely dangerous (by causing a nasal infection that could travel to the brain)[1]. However, there is no scientific evidence that such danger actually exists and there are no known reports of humans having health problems because of hair plucking or pulling.[
  • spray tan Return to the top
  • Sunless tanning (also known as spray tanning, self tanning, fake tanning, or UV-free tanning) refers to the application of chemicals to the skin to produce an effect similar in appearance to a more traditional suntan. The popularity of sunless tanning has risen since the 1960s after links were made by health authorities between exposure to the sun, and other sun tanning methods, such as sunbeds or tanning beds, and the incidence of skin cancer. Contents [hide] * 1 DHA-based products * 2 Tyrosine-based products * 3 Canthaxanthin-based products * 4 Melanotan hormone * 5 Temporary bronzers * 6 Risks * 7 See also * 8 References * 9 External links [edit] DHA-based products The most effective sunless tanning involves the use of lotions and sprays that contain dihydroxyacetone (DHA) as the active ingredient. DHA is not a dye, stain or paint, but causes a chemical reaction with the amino acids in the dead layer on the skin surface.[citation needed] This is similar to a reaction well known to food chemists called the Maillard reaction. This refers to the browning process during food manufacturing and storage. It does not involve skin pigmentation nor does it require exposure to ultraviolet light to initiate the color change. The effect is temporary and will fade gradually over 3 to 10 days. Some products use erythrulose combined with DHA. Erythrulose works identically to DHA on the skin surface, but develops more slowly. The two chemicals used together may produce a longer lasting sunless tan.[citation needed] Dihydroxyacetone or erythrulose may cause contact dermatitis. First time users of sunless tanning products are advised to apply the product to a small patch of skin and wait 24 hours before a full body application. These products can be applied at home, in the form of gels, lotions, mousses, sprays and wipes. Best results are obtained when applied to clean, dry skin. Bathing and swimming should be avoided until product is fully absorbed, which varies from one to six hours. More DHA is absorbed by the thicker skin on the hands and feet, so those areas should be skipped or cleaned immediately after application. Tanning lotions can be classified as bronzers, accelerators, and tingling lotions. Tingling lotions refer to indoor tanning lotion accelerators and maximizers that produce a tingling sensation when they are applied. It is believed that the tingle factor increases blood flow to the upper layers of the skin which brings more oxygen and affects melanin. This tingling sensation will vary depending on the skin type from mild to very strong.[1] Professional spraytans applications are available from spas, salons and gymnasiums by both hand held sprayer and in the form of sunless or UV-Free spray booths.[2] The enclosed booth, which resembles an enclosed shower stall, sprays the sunless tanning solution over the entire body. The U.S. Food and Drug Administration (FDA) states when using DHA-containing products as an all-over spray or mist in a commercial spray "tanning" booth, it may be difficult to avoid exposure in a manner for which DHA is not approved, including the area of the eyes, lips, or mucous membrane, or even internally. DHA is not approved by the FDA for inhalation. Consequently, FDA advises asking the following questions when considering commercial facilities where DHA is applied by spraying or misting: "Are consumers protected from exposure in the entire area of the eyes, in addition to the eyes themselves? Are consumers protected from exposure on the lips and all parts of the body covered by mucous membrane? Are consumers protected from internal exposure caused by inhaling or ingesting the product? If the answer to any of these questions is "no," the consumer is not protected from the unapproved use of this color additive. Consumers should request measures to protect their eyes and mucous membranes and prevent inhalation." [2] Airbrush spraytans are applied by professional technicians using specialized equipment including Laser guided spray guns designed for applying self tanning sprays, such as an airbrush, LVLP spraygun, and HVLP spraygun equipment types. The technician hand sprays the client from head to toe with a gentle solution misting. This custom spraying using overspray control systems is controlled and following FDA guidelines is simple. The portability of the equipment allows spray tanning services in a large variety of places, from beach kiosks and malls to in home application. DHA has been approved for cosmetic use by the FDA,[3] Health Canada and most of the EU member nations.[citation needed] It is considered nontoxic and noncarcinogenic[citation needed]. Because DHA does not use the skin's melanocytes to make the skin a tan color, it is recommended as a cosmetic disguising cover for vitiligo patients. DHA based sunless tanning has been recommended by the Skin Cancer Organization, the American Academy of Dermatology, the American Cancer Society and the American Medical Association.[citation needed] [edit] Tyrosine-based products Although gels, lotions or sprays that contain DHA are said to be the most reliable and useful, there are other types of products on the market. Tanning accelerators—lotions or pills[4] that usually contain the amino acid tyrosine -- claim that they stimulate and increase melanin formation, thereby accelerating the tanning process. These are used in conjunction with UV exposure. At this time, there is no scientific data available to support these claims. [edit] Canthaxanthin-based products Another sunless-tanning product is a tanning pill that contains canthaxanthin, which is most commonly used as a color additive in certain foods. Although the FDA has approved the use of canthaxanthin in food, it does not approve its use as a tanning agent. When used as a color additive, only very small amounts of canthaxanthin are necessary. As a tanning agent, however, much larger quantities are used. After canthaxanthin is consumed, it is deposited throughout the body, including in the layer of fat below the skin, which turns an orange-brown color. These types of tanning pills have been linked to various side effects, including hepatitis and canthaxanthin retinopathy, a condition in which yellow deposits form in the retina of the eye. Other side effects including damage to the digestive system and skin surface have also been noted. The FDA withdrew approval for use of canthaxanthin as a tanning agent, and has issued warnings concerning its use.[4] [edit] Melanotan hormone Afamelanotide, a synthetic melanocyte-stimulating hormone analog, which induces melanogenesis through activation of the melanocortin 1 receptor, is another alternative on the horizon. A 1991 clinical Investigational new drug trial conducted at the Department of Internal Medicine, University of Arizona Health Sciences Center with afamelanotide (then known by its amino acid formula [Nle4, D-Phe7] (NDP)-alpha-melanocyte-stimulating hormone) with 28, "healthy white men" who used a, "high-potency sunscreen during the trial" and concluded, "Human skin darkens as a response to a synthetic melanotropin given by subcutaneous injection. Skin tanning appears possible without potentially harmful exposure to ultraviolet radiation." [5] Afamelanotide in a subcutaneous implant form is currently undergoing clinical trials and being developed by a company in Australia. [edit] Temporary bronzers Bronzers are a temporary sunless tanning or bronzing option. These come in powders, sprays, mousse, gels, lotions and moisturizers. Once applied, they create a tan that can easily be removed with soap and water. Like make-up, these products tint or stain your skin only until they are washed off. They are often used for a "one-day" only tan, or to complement a DHA based sunless tan. Many formulations are available, and some have limited sweat or light water resistance. Most will create some light but visible rub-off onto snug clothing. Therefore they should not be applied under clothing, or where fabric and skin edges meet. Dark clothing will prevent the rub-off from being noticeable. While these products are much more safe than tanning beds, the color produced can sometimes look orangey and splotchy if applied incorrectly. A recent trend is that of lotions or moisturisers containing a gradual tanning agent. A slight increase in color is usually observable after the first use, but color will continue to darken the more the product is used. Air Brush tanning is a spray on tan done by a professional. It can last five to ten days fading with every shower. It is used for special occasions or to get a quick dark tan. At-home airbrush tanning kits and aerosol mists are also now available.
  • therapist Return to the top
  • An "occupational therapist' (OT) is trained in the practice of occupational therapy. The role of an occupational therapist is to work with a client to help them achieve a fulfilled and satisfied state in life through the use of "purposeful activity or interventions designed to achieve functional outcomes which promote health, prevent injury or disability and which develop, improve, sustain or restore the highest possible level of independence."[1]. A practical definition for OT can also be illustrated with the use of models such as the Occupational Performance Model (Australia), known as the OPM(A). At the core of this approach is the ideology that occupational therapists are concerned with the occupations of people and how these contribute to health.[2] Specifically it is a person’s occupational performance that influences their health and personal satisfaction of their individual needs. The OPM(A) is constructed on the following definition of Occupational Performance: "The ability to perceive, desire, recall, plan and carry out roles, routines, tasks and sub-tasks for the purpose of self-maintenance, productivity, leisure and rest in response to demands of the internal and/or external environment."[3] It can be seen that occupational performance, the roles it creates for a client, and the areas it can encompass are so far-reaching that an occupational therapist can work with a wide range of clients of various limitations who are being cared for in an array of settings.[4] Occupational therapy is about helping people do the day-to-day tasks that “occupy” their time, sustain themselves, and enable them to contribute to the wider community. Its these opportunities to “do” that occupational therapy provides that prove important and meaningful to the health of people.[5] [6] Contents [hide] * 1 Role o 1.1 Clients with permanent disabilities o 1.2 Work-related therapy o 1.3 With children o 1.4 With the elderly o 1.5 Mental health o 1.6 With Terminally Ill Patient o 1.7 With People with Chronic Pain o 1.8 Assessment * 2 See also * 3 Footnotes * 4 References * 5 External links [edit] Role Occupational therapists (OTs) help people of all ages to improve their ability to perform tasks in their daily living and working environments. They work with individuals who have conditions that are mentally, physically, developmentally, socially or emotionally disabling. They also help them to develop, recover, or maintain daily living and work skills. Occupational therapists help clients not only to improve their basic motor functions and reasoning abilities, but also to compensate for permanent loss of function. Their goal is to help clients have independent, productive, and satisfying lives. Occupational therapists assist clients in performing activities of all types, ranging from using a computer to caring for daily needs such as dressing, cooking, and eating. Physical exercises may be used to increase strength and dexterity, while other activities may be chosen to improve visual acuity and the ability to discern patterns. For example, a client with short-term memory loss might be encouraged to make lists to aid recall, and a person with coordination problems might be assigned exercises to improve hand-eye coordination. Occupational therapists also use computer programs to help clients improve decision-making, abstract-reasoning, problem solving, and perceptual skills, as well as memory, sequencing, and coordination —- all of which are important for independent living. Occupational therapists are often skilled in psychological strategies such as cognitive behavioural therapy and Acceptance and Commitment Therapy, and may use cognitive therapy especially when introducing people to new strategies for carrying out daily activities such as activity pacing or using effective communication strategies
  • wrinkles Return to the top
  • A wrinkle is a fold, ridge or crease in the skin. Skin wrinkles typically appear as a result of aging processes such as glycation or, temporarily, as the result of prolonged (more than a few minutes) immersion in water. Wrinkling in the skin is caused by habitual facial expressions, aging, sun damage, smoking, poor hydration, and various other factors.[1] With prolonged water exposure, the outer layer of skin starts to absorb water. The skin doesn't expand evenly, causing it to wrinkle. Depletion of water in the body, as occurs with dehydration, can also cause this puckering of the skin.[2] Cortisol causes degradation of skin collagen.[3] Contents [hide] * 1 Aging wrinkles o 1.1 Tretinoin o 1.2 Epidermal Growth Factor o 1.3 Glycosaminoglycans o 1.4 Botulinum toxin * 2 Pruney fingers * 3 Animals with wrinkles * 4 References * 5 External links [edit] Aging wrinkles [edit] Tretinoin Although the exact mode of action of tretinoin is unknown, current evidence suggests that tretinoin decreases cohesiveness of follicular epithelial cells. Additionally, tretinoin stimulates mitotic activity and increased turnover of follicular epithelial cells.[4] Tretinoin is better known by the brand name Retin-A. [edit] Epidermal Growth Factor Epidermal Growth Factor (EGF) is a small polypeptide of 53 amino acids and is a cytokine or cell messenger protein that stimulates epithelial cell proliferation. The discovery of EGF won Dr. Stanley Cohen a Nobel Prize in Physiology and Medicine in 1986. Taken internally, it is used to treat some devastating conditions of premature infants, as well as enlarged prostate in adult males. In cream form it stimulates cell renewal and Collagen production in the skin. It is also helpful for wound and burn healing and has achieved amazing cures of severe ulcerating skin diseases such as life-threatening Steven-Johnson Syndrome (SJS).[5] [edit] Glycosaminoglycans Glycosaminoglycans (GAGs) are produced by the body to maintain structural integrity in tissues and to maintain fluid balance. Hyaluronic acid is a type of GAG that promotes collagen synthesis, repair, and hydration. GAGs serve as a natural moisturizer and lubricant between epidermal cells to inhibit the production of matrix metalloproteinases (MMPs). Topical glycosaminoglycans supplements can help to provide temporary restoration of enzyme balance to slow or prevent matrix breakdown and consequent onset of wrinkle formation.[6] [edit] Botulinum toxin Botulinum toxin is a neurotoxin protein produced by the bacterium Clostridium botulinum. BOTOX® (onabotulinumtoxinA) is a specific form of botulinum toxin manufactured by Allergan Inc (U.S.) for both therapeutic as well as cosmetic use. Besides its cosmetic application, BOTOX® is used in the treatment of other conditions including migraine headache and cervical dystonia (spasmodic torticollis) (a neuromuscular disorder involving the head and neck).[7] In 2009, a new form of botulinum toxin became available to Americans. Dysport™ (abotulinumtoxinA), manufactured by Ipsen, received FDA approval and is now used to treat cervical dystonia as well as glabellar lines in adults. Dysport™ and BOTOX® are not interchangeable, however, as the molecular structure of the two drugs are different. Botulinum toxin treats wrinkles by immobilizing the muscles which cause wrinkles. It is not appropriate for the treatment of all wrinkles - it is indicated for the treatment of glabellar lines (between the eyebrows) in adults. Any other usage is not approved by the FDA and is considered "off-label" use. [edit] Pruney fingers A wrinkled finger after a warm bath The wrinkles that occur in skin after prolonged exposure to water are sometimes referred to as pruney fingers or water aging. This is a temporary skin condition where the skin on the palms of the hand or feet becomes wrinkly. In recent past the common explanation was based on water absorption in the keratin-laden epithelial skin when immersed in water,[8] causing the skin to expand and resulting in a larger surface area, forcing it to wrinkle. Usually the tips of the fingers and toes are the first to wrinkle because of a thicker layer of keratin and an absence of hairs which secrete the protective oil called sebum. In 1935 however, Lewis and Pickering were studying patients with palsy of a large nerve in the arm (the median nerve) when they discovered that skin wrinkling did not occur in the areas of the patients' skin normally innervated by the damaged nerve. This suggested that the nervous system plays an essential role in wrinkling, so the phenomenon could not be entirely explained simply by water absorption. Recent research shows that wrinkling is related to vasoconstriction.[9][10] Water probably initiates the wrinkling process by altering the balance of electrolytes in the skin as it diffuses into the hands and soles via their many sweat ducts. This could alter the stability of the membranes of the many neurons that synapse on the many blood vessels underneath skin, causing them to fire more rapidly. Increased neuronal firing causes blood vessels to constrict, decreasing the amount of fluid underneath the skin. This decrease in fluid would cause a decrease in tension, causing the skin to become wrinkly.[11] This insight resulted in bedside tests for nerve damage and vasoconstriction. Wrinkling is often scored with immersion of the hands for 30 minutes in water or EMLA cream with measurements steps of 5 minutes, and counting the number of visible wrinkles in time. Not all healthy persons have finger wrinkling after immersion, so it would be safe to say that sympathetic function is preserved if finger wrinkling after immersion in water is observed, but if the fingers emerge smooth it cannot be assumed that there is a lesion to the autonomic supply or to the peripheral nerves of the hand.[12] [edit] Animals with wrinkles Shar Pei puppies Examples of wrinkles can be found in various animal species that grow loose, excess skin, particularly when they are young. Several breeds of dog, such as the Pug and the Shar Pei, have been bred to exaggerate this trait. In dogs bred for fighting, this is the result of selection for loose skin, which confers a protective advantage. Wrinkles are also associated with neoteny, as they are a trait associated with juvenile animals.
  • hair removal Return to the top
  • Hair removal is the removal of body hair, and describes the methods used to achieve that result. Hair typically grows all over the human body during and after puberty. Men tend to have more body hair than women. Both men and women tend to have hair on their head, eyebrows, eyelashes, armpits, pubic region and legs; and men also have hair on their face, abdomen, back and chest. Hair does not generally grow on the palms of the hands, the lips, certain areas of the genital structure, or the soles of the feet.[1] Forms of hair removal are practised for a number of reasons, including cultural, sexual, medical and religious. Forms of hair removal have been practiced in almost all human cultures. The methods used to remove hair have varied in different times and regions, but shaving is the most common method. Contents [hide] * 1 Forms of hair removal * 2 Cultural and sexual aspects * 3 Other reasons o 3.1 Religious reasons o 3.2 Medical reasons o 3.3 Male-to-female gender reassignment o 3.4 In military institutions o 3.5 Sporting reasons o 3.6 As punishment * 4 Hair removal methods o 4.1 Temporary o 4.2 Permanent hair removal o 4.3 Permanent hair reduction o 4.4 Experimental or banned methods o 4.5 Doubtful methods * 5 Advantages and disadvantages * 6 See also * 7 References o 7.1 Notes o 7.2 Bibliography * 8 External links [edit] Forms of hair removal Depilation is the removal of the part of the hair above the surface of the skin. The most common form of depilation is shaving or trimming. Another option is the use of chemical depilatories, which work by breaking the disulfide bonds that link the protein chains that give hair its strength, making the hair disintegrate. Epilation is the removal of the entire hair, including the part below the skin. Methods include waxing, sugaring, epilation devices, lasers, threading, intense pulsed light or electrology. Hair is also sometimes removed by plucking with tweezers. [edit] Cultural and sexual aspects Woman's underarm hair See also: Bikini waxing Each culture of human society has developed social norms relating to the presence or absence of body hair, which has changed from one time to another. Different standards can apply to males and females. People whose hair falls outside a culture's aesthetic standards may experience real or perceived social acceptance problems. For example, for women in several Western societies, exposure in public of body hair other than head hair, eyelashes and eyebrows is generally considered to be unaesthetic, undesirable and embarrassing.[2] Such hair can be removed, or can be covered up. In some cultures, the exposure by a woman of head hair is also frowned upon, but removal of head hair is not the norm. This is the situation in many Muslim countries where in public a woman's hair is expected to be covered by a headscarf or is a part of the hijab covering. In Middle Eastern societies, it has been the norm and local custom for many centuries, and regarded as proper hygiene, for a woman to remove body hair, especially under the arms and pubic hair,[3] known as an act of sunan al-fitra. In Western cultures, removal of body hair by women (if performed) is more commonly for aesthetic reasons, and less for reasons of hygiene. With the increased popularity in many countries of shorter dresses and swimsuits during the 20th century and the consequential exposure of parts of the body on which body hair is commonly found, there has been an increase in the practice of removing unwanted body hair, such as on legs, underarms and elsewhere.[4] People may also remove some or all of their pubic hair for aesthetic or sexual reasons.[5] (see bikini waxing) However, some women in Western cultures choose not to remove hair from their bodies, either as a preference or as an act of defiance against what they regard to be an oppressive ritual. Similarly, some men in Western cultures show defiance by choosing to shave body hair, such as on the legs or underarms. Many men in Western cultures shave their facial hair, so only a minority of men have a beard, even though fast-growing facial hair must be shaved daily to achieve a clean-shaven or hairless look. On the contrary, in some Eastern cultures (e.g.: Eastern Turkish and Iranian) a display of a beard is considered to be a display of wisdom. Some men shave because they cannot grow a "full" beard (generally defined as an even density from cheeks to neck), because their beard color is different from their scalp hair color, or because their facial hair grows in many directions, making a groomed look difficult. Some men shave because their beards are very coarse, causing itchiness and irritation. Some men grow a beard or moustache from time to time to change their appearance. Some men shave their heads, either as a fashion statement, because they find a shaved head preferable to the appearance of male pattern baldness, or in order to attain enhanced cooling of the skull – particularly for people suffering from hyperhidrosis. A much smaller number of women also shave their heads, often as a fashion or political statement. Some women also shave their heads for cultural or social reasons. In India, tradition required widows in some sections of the society to shave their heads as part of being ostracized (see widowhood in Hinduism). The outlawed custom is still infrequently encountered mostly in rural areas, the society at large and the government are working to end the practice of ostracizing widows.[6] In addition, it continues to be common practice for men and women to shave their heads prior to embarking on a pilgrimage. Ancient Egyptian priests also shaved or depilated all over daily, so as to present a "pure" body before the images of the gods. [edit] Other reasons [edit] Religious reasons Head-shaving is a part of some Buddhist, Christian, Jain and Hindu traditions. Buddhist and Christian monks generally undergo some form of head-shaving or tonsure during their ordination; in Thailand monks shave their eyebrows as well. Brahmin children have their heads ritualistically shaved before beginning school. In some parts of the Theravada Buddhist world, it is common practice to shave the heads of children. Weak or sickly children are often left with a small topknot of hair, to gauge their health and mark them for special treatment. When health improves, the lock is cut off. In Judaism, there is no obligation to remove hair; nor is there a general prohibition to removing hair. However, there is a prohibition for men using a razor to shave their beards or sideburns; and, by custom, neither men nor women cut their hair, and men shave, during a 30-day mourning period after the death of an immediate family member. The Bahá'í Faith recommends against complete and long-term head-shaving outside of medical purposes. It is not currently practiced as a law, contingent upon future decision by the Universal House of Justice, its highest governing body. Sikhs take an even stronger stance, opposing all forms of hair removal. One of the Sikh "Five Ks" is Kesh, meaning "uncut hair". To Sikhs, the maintenance and management of long hair is a manifestation of one's piety. Muslim law (Sharia) puts hair in three categories: that which it is recommended to remove (moustache, pubic and armpit hair), that which it is recommended to keep (the beard), and that which is the object of limited recommendation (foot, hand, back, and chest hair). Removal of armpit and pubic hair is a hygienic practice[citation needed] which was taught by the Islamic prophet Muhammad and which was enumerated as having been part of practices conforming to man's premortal (Fitrah) nature practiced by all prophets of God. A muslim may trim or cut hair on head. The hairs on the chest and the back but may be removed. In the 9th century, the use of chemical depilatories for women was introduced by Ziryab in Al-Andalus.[7] [edit] Medical reasons Body hair on an unusually hirsute male The body hair of surgical patients may be removed before surgery. In the past this may have been achieved by shaving, but that is now considered counter-productive, so clippers or chemical depilatories may be used instead.[8] The shaving of hair has sometimes been used in attempts to eradicate lice or to minimize body odor due to accumulation of odor-causing micro-organisms in hair. Some people with trichiasis find it medically necessary to remove ingrown eyelashes. Incorrect shaving (shaving against the grain) can often cause ingrown hairs. Many forms of cancer require chemotherapy, which often causes severe and irregular hair loss. For this reason, it is common for cancer patients to shave their heads even before starting chemotherapy. In extreme situations people may need to remove all body hair to prevent or combat infestation by lice, fleas and other parasites. Such a practice was used, for example, in Ancient Egypt.
  • Hair removal is the practice of removing body hair, and describes the methods used to achieve that result. Hair typically grows all over the human body during and after puberty. Men tend to have more body hair than women. Both men and women tend to have hair on their head, eyebrows, eyelashes, armpits, pubic region and legs; and men also have hair on their face, abdomen, back and chest. Hair does not generally grow on the palms of the hands, the lips, certain areas of the genital structure, or the soles of the feet.[1] Forms of hair removal are practised for a number of reasons, including cultural, sexual, medical and religious. Forms of hair removal have been practiced in almost all human cultures. The methods used to remove hair have varied in different times and regions, but shaving is the most common method. Contents [hide] * 1 Forms of hair removal * 2 Cultural and sexual aspects * 3 Other reasons o 3.1 Religious reasons o 3.2 Medical reasons o 3.3 Male-to-female gender reassignment o 3.4 In military institutions o 3.5 Sporting reasons o 3.6 As punishment * 4 Hair removal methods o 4.1 Temporary o 4.2 Permanent hair removal o 4.3 Permanent hair reduction o 4.4 Experimental or banned methods o 4.5 Doubtful methods * 5 Advantages and disadvantages * 6 See also * 7 References o 7.1 Notes o 7.2 Bibliography * 8 External links [edit] Forms of hair removal Depilation is the removal of the part of the hair above the surface of the skin. The most common form of depilation is shaving or trimming. Another option is the use of chemical depilatories, which work by breaking the disulfide bonds that link the protein chains that give hair its strength, making the hair disintegrate. Epilation is the removal of the entire hair, including the part below the skin. Methods include waxing, sugaring, epilation devices, lasers, threading, intense pulsed light or electrology. Hair is also sometimes removed by plucking with tweezers. [edit] Cultural and sexual aspects Woman's underarm hair See also: Bikini waxing Each culture of human society has developed social norms relating to the presence or absence of body hair, which has changed from one time to another. Different standards can apply to males and females. People whose hair falls outside a culture's aesthetic standards may experience real or perceived social acceptance problems. For women, for example, exposure in public of body hair other than head hair, eyelashes and eyebrows is generally considered to be unaesthetic, undesirable and embarrassing.[2] Such hair can be removed, or can be covered up. In some cultures, the exposure by a woman of head hair is also frowned upon, but removal of head hair is not the norm. This is the situation in most Muslim countries where in public a woman's hair is expected to be covered by a headscarf or is a part of the hijab covering. In Middle Eastern societies, it has been the norm and local custom for many centuries, and regarded as proper hygiene, for a woman to remove body hair, especially under the arms and pubic hair,[3] known as an act of sunan al-fitra. In Western cultures, removal of body hair by women (if performed) is more commonly for aesthetic reasons, and less for reasons of hygiene. With the increased popularity in many countries of shorter dresses and swimsuits during the 20th century and the consequential exposure of parts of the body on which body hair is commonly found, there has been an increase in the practice of removing unwanted body hair, such as on legs, underarms and elsewhere.[4] People may also remove some or all of their pubic hair for aesthetic or sexual reasons.[5] (see bikini waxing) Some women in Western cultures choose not to remove hair from their bodies, either as a preference or as an act of defiance against what they regard to be an oppressive ritual. On the other hand, some men in Western cultures show defiance by choosing to shave body hair, such as on the legs or underarms. Many men in Western cultures shave their facial hair, so only a minority of men have a beard, even though fast-growing facial hair must be shaved daily to achieve a clean-shaven or hairless look. On the contrary, in some Eastern cultures (e.g.: Eastern Turkish and Iranian) a display of a beard is considered to be a display of wisdom. Some men shave because they cannot grow a "full" beard (generally defined as an even density from cheeks to neck), because their beard color is different from their scalp hair color, or because their facial hair grows in many directions, making a groomed look difficult. Some men shave because their beards are very coarse, causing itchiness and irritation. Some men grow a beard or moustache from time to time to change their appearance. Some men shave their heads, either as a fashion statement, because they find a shaved head preferable to the appearance of male pattern baldness, or in order to attain enhanced cooling of the skull – particularly for people suffering from hyperhidrosis. A much smaller number of women also shave their heads, often as a fashion or political statement. Some women also shave their heads for cultural or social reasons. In India, tradition required widows in some sections of the society to shave their heads as part of being ostracized (see widowhood in Hinduism). The outlawed custom is still infrequently encountered mostly in rural areas, the society at large and the government are working to end the practice of ostracizing widows.[6] In addition, it continues to be common practice for men and women to shave their heads prior to embarking on a pilgrimage. Ancient Egyptian priests also shaved or depilated all over daily, so as to present a "pure" body before the images of the gods. [edit] Other reasons [edit] Religious reasons Head-shaving is a part of some Buddhist, Christian, Jain and Hindu traditions. Buddhist and Christian monks generally undergo some form of head-shaving or tonsure during their ordination; in Thailand monks shave their eyebrows as well. Brahmin children have their heads ritualistically shaved before beginning school. In some parts of the Theravada Buddhist world, it is common practice to shave the heads of children. Weak or sickly children are often left with a small topknot of hair, to gauge their health and mark them for special treatment. When health improves, the lock is cut off. In Judaism, there is no obligation to remove hair; nor is there a general prohibition to removing hair. However, there is a prohibition for men using a razor to shave their beards or sideburns; and, by custom, neither men nor women cut their hair, and men shave, during a 30-day mourning period after the death of an immediate family member. The Bahá'í Faith recommends against complete and long-term head-shaving outside of medical purposes. It is not currently practiced as a law, contingent upon future decision by the Universal House of Justice, its highest governing body. Sikhs take an even stronger stance, opposing all forms of hair removal. One of the Sikh "Five Ks" is Kesh, meaning "uncut hair". To Sikhs, the maintenance and management of long hair is a manifestation of one's piety. Muslim law (Sharia) puts hair in three categories: that which it is recommended to remove (moustache, pubic and armpit hair), that which it is recommended to keep (the beard), and that which is the object of limited recommendation (foot, hand, back, and chest hair). Removal of armpit and pubic hair is a hygienic practice[citation needed] which was taught by the Islamic prophet Muhammad and which was enumerated as having been part of practices conforming to man's premortal (Fitrah) nature practiced by all prophets of God. A muslim may trim or cut hair on head. The hairs on the chest and the back but may be removed. In the 9th century, the use of chemical depilatories for women was introduced by Ziryab in Al-Andalus.[7] [edit] Medical reasons Body hair on an unusually hirsute male The body hair of surgical patients may be removed before surgery. In the past this may have been achieved by shaving, but that is now considered counter-productive, so clippers or chemical depilatories may be used instead.[8] The shaving of hair has sometimes been used in attempts to eradicate lice or to minimize body odor due to accumulation of odor-causing micro-organisms in hair. Some people with trichiasis find it medically necessary to remove ingrown eyelashes. Incorrect shaving (shaving against the grain) can often cause ingrown hairs. Many forms of cancer require chemotherapy, which often causes severe and irregular hair loss. For this reason, it is common for cancer patients to shave their heads even before starting chemotherapy. In extreme situations people may need to remove all body hair to prevent or combat infestation by lice, fleas and other parasites. Such a practice was used, for example, in Ancient Egypt. [edit] Male-to-female gender reassignment Male-to-female transsexual women who are preparing for sex reassignment surgery usually remove their facial beard hair, typically either by electrolysis or laser, or a combination of the two procedures. While this is commonly done entirely before surgery, some patients will start the procedure before surgery, and finish after a few months to several years, often due to cost. In addition, some surgeons recommend that a part of the pubic hair be removed prior to surgery as well, usually by electrolysis. Since the neovagina is created using the skin of the penis and part of the scrotum, which usually has active follicles, the hair is removed from these areas prior to surgery, in order for the genitals to be fashioned without the concern of hair growth inside of the neovagina. In some cases, the surgeon scrapes the underside of the skin to remove the follicles at or near the beginning of the surgery, eliminating the need for post-surgical hair removal. [edit] In military institutions Question book-new.svg This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (February 2010) A close-cropped or completely shaven haircut is common in military organizations. In field environments, soldiers are susceptible to infestation of lice, ticks, and fleas. In addition short hair is also more difficult for an enemy to grab hold of in hand to hand combat. The practice serves to cultivate a group oriented environment through the process of removing exterior signs of individuality. In many militaries - Russia and the other ex USSR states for example, head-shaving is mandatory for males when beginning their training. However, even after the initial recruitment phase, when head-shaving is no longer required, many soldiers maintain a completely or partially shaven hairstyle (such as a "high and tight", "flattop" or "buzz cut") for personal convenience and an exterior symbol of military solidarity. Head-shaving is not required of females in military service, although they must have their hair cut or tied to regulation length. Russian and other ex Soviet republic armies also require males to maintain clean-shaven faces, allegedly because facial hair can prevent an air-tight seal between the face and breathing or safety equipment, such as a pilot's oxygen mask, a diver's mask, or a soldier's gas mask. Alternatively, Foreign Legion sappers have traditionally worn beards as a sign of their rank and experience. Similarly the Imperial Guard of the Grande Armée were allowed to grow beards as a sign of their prized position. European armies before (and to some extent during) the Napoleonic wars allowed soldiers to grow and lacquer pigtails, sometimes held in place by bone combs or regimental colour ribbons or bows. In the pre-Napoleonic era, the wearing of wigs, even within the ranks was commonplace, though impractical in such places as India and the Americas. Selous Scouts, once through training and induction, were expressly forbidden from cutting their hair in any way that might indicate that they were soldiers, allowing them to engage in anti-insurgency warfare amongst the rural population of Rhodesia (now Zimbabwe). Tolerance of Sikh religious beliefs with regards to hair and beards has for some time been commonplace in most armies of former British colonies. [edit] Sporting reasons It is a common practice for professional and amateur road cyclists to remove leg hair for a number of reasons. In the case of a crash, the absence of the leg hair means the injuries (usually road rash) can be cleaned up more efficiently, and treatment is not impeded. Professional cyclists also receive regular leg massages, and the absence of hair reduces the friction and increases their comfort and effectiveness. It is also common for professional swimmers to shave hair off their legs to prevent drag with the water from slowing them down. [edit] As punishment In some situations, people's hair is shaved as a punishment or form of humiliation. After World War II, head-shaving was a common punishment in France, the Netherlands, and Norway for women who had collaborated with the Nazis during the occupation, and, in particular, for women who had "collaborated" sexually.[9] In the United States, during the Vietnam War, conservative students would sometimes attack student radicals or "hippies" by shaving beards or cutting long hair. One notorious incident occurred at Stanford University, when unruly fraternity members grabbed Resistance founder (and student-body president) David Harris, cut off his long hair, and shaved his beard. In Arab countries, shaving off head-hair is sometimes used to shame and humiliate male prisoners. During European witch-hunts of the Medieval and Early Modern periods, alleged witches were stripped naked and their entire body shaved to discover the so-called witches' marks. The discovery of witches' marks was then used as evidence in trials.[10] [edit] Hair removal methods Many products on the market have proven fraudulent. Many other products exaggerate the results or ease of use. [edit] Temporary "Depilation", or removal of hair to the level of the skin, lasts several hours to several days and can be achieved by * Shaving or trimming (manually or with electric shavers) * Depilatories (creams or "shaving powders" which chemically dissolve hair) * Friction (rough surfaces used to buff away hair) "Epilation", or removal of the entire hair from the root, lasts several days to several weeks and may be achieved by * Tweezing (hairs are tweezed, or pulled out, with tweezers or with fingers) * Waxing (a hot or cold layer is applied and then removed with porous strips) * Sugaring (similar to waxing, but with a sticky paste) * Threading (also called fatlah or khite, in which a twisted thread catches hairs as it is rolled across the skin) * Burning off with hot wax can damage the cells and prevent hair from ever growing in the unwanted spot again.[11] * Use of Turmeric along with other ingredients like besan powder and milk * Epilators (mechanical devices that rapidly grasp hairs and pull them out) * Prescription oral medications * Drugs that directly attack hair growth or inhibit the development of new hair cells. Hair growth will become less and less until it finally stops; normal depilation/epilation will be performed until that time. Hair growth will return to normal if use of product discontinued. Products include the prescription drug Vaniqa, with the active ingredient eflornithine hydrochloride inhibiting the enzyme ornithine decarboxylase, preventing new hair cells from producing putrescine for stabilizing their DNA. [edit] Permanent hair removal For over 130 years, electrolysis has been and remains the only 100% permanent hair removal method recognized by government regulatory agencies such as the FDA. This technique permanently destroys germ cells responsible for hair growth by way of insertion of a fine probe in the hair follicle and the application of a current adjusted to each hair type and treatment area. [edit] Permanent hair reduction * Photoepilation o Laser hair removal (lasers and laser diodes) o Intense pulsed light (high-energy lamps) o Diode epilation (high energy LEDs but not laser diodes) Contrary to what is often announced, Photoepilation is not a permanent hair removal method but a permanent hair reduction method. This means that although laser treatments with these devices will permanently reduce the total number of body hairs, they will not result in a permanent removal of all hair.[12] [edit] Experimental or banned methods * Photodynamic therapy for hair removal (experimental) * X-ray hair removal is an efficient, and usually permanent, hair removal method, but also causes severe health problems, occasional disfigurement, and even death.[13] It is illegal in the United States. [edit] Doubtful methods Many methods have been proposed or sold over the years without published clinical proof they can work as claimed. * Electric tweezers * Transdermal electrolysis * Transcutaneous hair removal * Photoepilators * Microwaves * Foods and Dietary supplements * Non prescription topical preparations (also called "hair inhibitors", "hair retardants", or "hair growth inhibitors") [edit] Advantages and disadvantages There are several disadvantages to many of these hair removal methods. Most are not permanent, can cause medical problems and permanent damage, or have very high costs. Some of these methods are still in the testing phase and their methods have not been clinically proven. One should seek the advice of a doctor-supervised facility when choosing these hair removal methods. One issue, that can be considered an advantage or a disadvantage depending upon an individual's viewpoint, is that removing hair has the effect of removing information about the individual's hair growth patterns due to genetic predisposition, illness, androgen levels (such as from pubertal hormonal imbalances or drug side effects), and/or gender status.
  • delivery Return to the top
  • de·liv·er·y    /dɪˈlɪvəri/ Show Spelled[dih-liv-uh-ree] Show IPA –noun, plural -er·ies. 1. the carrying and turning over of letters, goods, etc., to a designated recipient or recipients. 2. a giving up or handing over; surrender. 3. the utterance or enunciation of words. 4. vocal and bodily behavior during the presentation of a speech: a speaker's fine delivery. 5. the act or manner of giving or sending forth: the pitcher's fine delivery of the ball. 6. the state of being delivered of or giving birth to a child; parturition. 7. something delivered: The delivery is late today. 8. Commerce . a shipment of goods from the seller to the buyer. 9. Law . a formal act performed to make a transfer of property legally effective: a delivery of deed. 10. Printing . Also called delivery end . the part of a printing press where the paper emerges in printed form. 11. Archaic . release or rescue; liberation; deliverance. Use delivery in a Sentence See images of delivery Search delivery on the Web Origin: 1400–50; late ME delyvere, delyvery < AF delivrée, n. use of fem. ptp. of delivrer to deliver, with suffix assimilated to -ery —Related forms mis·de·liv·er·y, noun, plural -er·ies. non·de·liv·er·y, noun, plural -er·ies. post·de·liv·er·y, adjective pre·de·liv·er·y, noun, plural -er·ies. re·de·liv·er·y, noun, plural -er·ies. Dictionary.com Unabridged Based on the Random House Dictionary, © Random House, Inc. 2011. Cite This Source | Link To delivery Explore the Visual Thesaurus » Related Words for : delivery bringing, manner of speaking, speech, legal transfer, livery View more related words » World English Dictionary delivery (dɪˈlɪvərɪ) [Click for IPA pronunciation guide] — n , pl -eries 1. a. the act of delivering or distributing goods, mail, etc b. something that is delivered c. ( as modifier ): a delivery service 2. the act of giving birth to a child: she had an easy delivery 3. manner or style of utterance, esp in public speaking or recitation: the chairman had a clear delivery 4. the act of giving or transferring or the state of being given or transferred 5. the act of rescuing or state of being rescued; liberation 6. sport a. the act or manner of bowling or throwing a ball b. the ball so delivered: a fast delivery 7. an actual or symbolic handing over of property, a deed, etc 8. the discharge rate of a compressor or pump 9. (in South Africa) the supply of basic services to communities deprived under apartheid Collins English Dictionary - Complete & Unabridged 10th Edition 2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009 Cite This Source Word Origin & History delivery late 15c., "action of handing over to another," from Anglo-Fr. delivrée , fem. pp. of délivrer (see deliver). Childbirth sense is attested from 1570s. Of speech, from 1580s. Of a blow, throw of a ball, etc., from 1702. Online Etymology Dictionary, © 2010 Douglas Harper
  • Delivery is the process of transporting goods. Most goods are delivered through a transportation network. Cargo (physical goods) are primarily delivered via roads and railroads on land, shipping lanes on the sea and airline networks in the air. Certain specialized goods may be delivered via other networks, such as pipelines for liquid goods, power grids for electrical power and computer networks such as the Internet or broadcast networks for electronic information. The general process of delivering goods is known as distribution. The study of effective processes for delivery and disposition of goods and personnel is called Logistics. Firms that specialize in delivering commercial goods from point of production or storage to point of sale are generally known as distributors, while those that specialize in the delivery of goods from point of sale to the consumer are known as delivery services. Postal, courier, and relocation services also deliver goods for commercial and private interests. Contents [hide] * 1 Consumer goods delivery * 2 Delivery vehicles * 3 Periodic deliveries * 4 See also [edit] Consumer goods delivery A Dairy Crest Smiths Elizabethan electric Milk float for use of delivering fresh milk to peoples doorsteps. Most consumer goods are delivered from a point of production (factory or farm) through one or more points of storage (warehouses) to a point of sale (retail store), where the consumer buys the good and is responsible for its transportation to point of consumption. There are many variations on this model for specific types of goods and modes of sale. Products sold via catalogue or the Internet may be delivered directly from the manufacturer or warehouse to the consumer's home, or to an automated delivery booth. Small manufacturers may deliver their products directly to retail stores without warehousing. Some manufacturers maintain factory outlets which serve as both warehouse and retail store, selling products directly to consumers at wholesale prices (although many retail stores falsely advertise as factory outlets). Building, construction, landscaping and like materials are generally delivered to the consumer by a contractor as part of another service. Some highly perishable or hazardous goods, such as radioisotopes used in medical imaging, are delivered directly from manufacturer to consumer. Home delivery is often available for fast food and other convenience products, e.g. pizza delivery. Sometimes home delivery of supermarket goods is possible. A milk float is a small battery electric vehicle (BEV), specifically designed for the delivery of fresh milk. [edit] Delivery vehicles ASDA Mercedes-Benz Sprinter delivery vans which are used to delivery groceries to people's doors. Vehicles are often specialized to deliver different types of goods. On land, semi-trailers are outfitted with various trailers such as box trailers, flatbeds, car carriers, tanks and other specialized trailers, while railroad trains include similarly specialized cars. Armored cars, dump trucks and concrete mixers are examples of vehicles specialized for delivery of specific types of goods. On the sea, merchant ships come in various forms, such as cargo ships, oil tankers and fishing boats. Freight aircraft are used to deliver cargo. Often, passenger vehicles are used for delivery of goods. These include busses, vans, pick-ups, cars (e.g., for mail or pizza delivery), motorcycles and bicycles (e.g., for newspaper delivery). A significant amount of freight is carried in the cargo holds of passenger ships and aircraft. Everyday travelers, known as a casual courier, can also be used to deliver goods. Delivery to remote, primitive or inhospitable areas may be accomplished using small aircraft, snowmobiles, horse-drawn vehicles, dog sleds, pack animals, on foot, or by a variety of other transport methods. [edit] Periodic deliveries Some products are delivered to consumers on a periodic schedule. At the beginning of the 20th century, perishable farm items such as milk, eggs and ice, were delivered weekly to customers by local farms. With the advent of home refrigeration and better distribution methods, these products are today largely delivered through the same retail distribution systems as other food products. Some products, most notably heating fuels, are still delivered periodically. Long after the ice man and milkman were a thing of the past, cultural references to affairs between housewives and delivery men lingered. A recurrent cartoon theme was that of a family whose children resembled a visiting milkman. This also explains the following lines of Jeannie C. Riley's 1968 hit song Harper Valley PTA: There's old Bobby Taylor sitting there, and seven times he's asked me for a date, And Mrs. Taylor sure seems to use a lot of ice whenever he's away.
  • straightener Return to the top
  • Hair straightening is a hair styling technique which involves the flattening and straightening of hair in order to give it a smooth, streamlined, and 'sleek' appearance. It may be accomplished by using hair irons and hot combs, chemical relaxers, Japanese hair straightening, or Brazilian hair straightening. In addition, some shampoos, and conditioners and hair gels can help to make hair temporarily straight. The process is often called "rebonding" in Southeast Asia (e.g. Malaysia and Philippines).[1] Hair irons and hot combs can only temporarily modify hair texture, whereas relaxers and the other methods permanently alter the structure of the hair, although new hair growth is not affected. The drug interferon alpha has been reported as being shown to modify hair follicles causing permanent change in a person's hair texture.[2]
  • light therapy Return to the top
  • Light therapy or phototherapy (classically referred to as heliotherapy) consists of exposure to daylight or to specific wavelengths of light using lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light, usually controlled with various devices. The light is administered for a prescribed amount of time and, in some cases, at a specific time of day. Commercially, the common use of the term is associated with the treatment of skin, sleep disorder and some psychiatric disorders. Light therapy directed at the skin is used to treat acne vulgaris and neonatal jaundice. Light therapy which strikes the retina of the eyes is used to treat circadian rhythm disorders such as delayed sleep phase syndrome and can also be used to treat seasonal affective disorder, with some support for its use also with non-seasonal psychiatric disorders. The medical (mainstream and complementary and alternative medicine) applications of light therapy also include pain management, accelerated wound healing, hair growth, acupuncture, improvement in blood properties and blood circulation, and sinus-related diseases and disorders. Many of these use low level laser therapy and red light therapy in the 620–660 nm range. The National Center for Complementary and Alternative Medicine has listed "Light Therapy" as a practice that involves "veritable forms of energy that include those involving electromagnetic fields".[1] Contents [hide] * 1 History * 2 Skin related o 2.1 Acne vulgaris o 2.2 Psoriasis and eczema o 2.3 Tanning o 2.4 Wound healing o 2.5 Photodynamic therapy * 3 Mood and sleep related o 3.1 Light boxes o 3.2 Seasonal affective disorder o 3.3 Non-seasonal depression o 3.4 Circadian rhythm sleep disorders + 3.4.1 Chronic CRSD + 3.4.2 Situational CRSD * 4 Neonatal jaundice * 5 Parkinson's disease * 6 Safety o 6.1 Side effects * 7 See also * 8 References [edit] History Indian medical literature dating to 1500 BC describes a treatment combining herbs with natural sunlight to treat non-pigmented skin areas. Buddhist literature from about 200 AD and 10th-century Chinese documents made similar references. Danish physician Nils Finsen is believed to be the father of modern phototherapy. He developed the first artificial light source for this purpose, and used his invention to treat lupus vulgaris. He received the Nobel Prize in Physiology or Medicine in 1903. Since then a large array of treatments have been developed from the use of controlled light. Though the popular consumer understanding of "light therapy" is associated with treating seasonal affective disorder, other applications, growing in recognition include the application of low level laser, red light, near-infrared and ultraviolet lights for pain management, hair growth, skin treatments, accelerated wound healing. The modalities include light-based acupuncture, directing light on painful areas, blood irradiation therapy and photodynamic therapy.
  • led Return to the top
  • A light-emitting diode (LED) (pronounced /ˌɛl iː ˈdiː/, L-E-D[1]) is a semiconductor light source. LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. Introduced as a practical electronic component in 1962,[2] early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness. When a light-emitting diode is forward biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. An LED is often small in area (less than 1 mm2), and integrated optical components may be used to shape its radiation pattern.[3] LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output. Light-emitting diodes are used in applications as diverse as replacements for aviation lighting, automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The compact size, the possibility of narrow bandwidth, switching speed, and extreme reliability of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances. Contents [hide] * 1 History o 1.1 Discoveries and early devices o 1.2 Practical use o 1.3 Continuing development * 2 Technology o 2.1 Physics o 2.2 Refractive Index + 2.2.1 Transition coatings o 2.3 Efficiency and operational parameters o 2.4 Lifetime and failure * 3 Colors and materials o 3.1 Ultraviolet and blue LEDs o 3.2 White light + 3.2.1 RGB systems + 3.2.2 Phosphor-based LEDs + 3.2.3 Other white LEDs o 3.3 Organic light-emitting diodes (OLEDs) o 3.4 Quantum dot LEDs (experimental) * 4 Types o 4.1 Miniature o 4.2 Mid-range o 4.3 High power o 4.4 Application-specific variations * 5 Considerations for use o 5.1 Power sources o 5.2 Electrical polarity o 5.3 Safety o 5.4 Advantages o 5.5 Disadvantages * 6 Applications o 6.1 Indicators and signs o 6.2 Lighting o 6.3 Smart lighting o 6.4 Sustainable lighting + 6.4.1 Environmentally friendly options + 6.4.2 Economically sustainable o 6.5 Non-visual applications o 6.6 Light sources for machine vision systems * 7 See also * 8 References o 8.1 Notes o 8.2 Further reading * 9 External links [edit] History [edit] Discoveries and early devices Green electroluminescence from a point contact on a crystal of SiC recreates H. J. Round's original experiment from 1907. Electroluminescence was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat's-whisker detector.[4][5] Russian Oleg Vladimirovich Losev independently reported on the creation of an LED in 1927.[6][7] His research was distributed in Russian, German and British scientific journals, but no practical use was made of the discovery for several decades.[8][9] Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955.[10] Braunstein observed infrared emission generated by simple diode structures using gallium antimonide (GaSb), GaAs, indium phosphide (InP), and silicon-germanium (SiGe) alloys at room temperature and at 77 kelvin. In 1961, American experimenters Robert Biard and Gary Pittman working at Texas Instruments,[11] found that GaAs emitted infrared radiation when electric current was applied and received the patent for the infrared LED. The first practical visible-spectrum (red) LED was developed in 1962 by Nick Holonyak Jr., while working at General Electric Company.[2] Holonyak is seen as the "father of the light-emitting diode".[12] M. George Craford,[13] a former graduate student of Holonyak, invented the first yellow LED and improved the brightness of red and red-orange LEDs by a factor of ten in 1972.[14] In 1976, T.P. Pearsall created the first high-brightness, high efficiency LEDs for optical fiber telecommunications by inventing new semiconductor materials specifically adapted to optical fiber transmission wavelengths.[15] Until 1968, visible and infrared LEDs were extremely costly, on the order of US $200 per unit, and so had little practical use.[16] The Monsanto Company was the first organization to mass-produce visible LEDs, using gallium arsenide phosphide in 1968 to produce red LEDs suitable for indicators.[16] Hewlett Packard (HP) introduced LEDs in 1968, initially using GaAsP supplied by Monsanto. The technology proved to have major uses for alphanumeric displays and was integrated into HP's early handheld calculators. In the 1970s commercially successful LED devices at under five cents each were produced by Fairchild Optoelectronics. These devices employed compound semiconductor chips fabricated with the planar process invented by Dr. Jean Hoerni at Fairchild Semiconductor.[17] The combination of planar processing for chip fabrication and innovative packaging methods enabled the team at Fairchild led by optoelectronics pioneer Thomas Brandt to achieve the needed cost reductions. These methods continue to be used by LED producers.[18] [edit] Practical use The first commercial LEDs were commonly used as replacements for incandescent and neon indicator lamps, and in seven-segment displays,[19] first in expensive equipment such as laboratory and electronics test equipment, then later in such appliances as TVs, radios, telephones, calculators, and even watches (see list of signal uses). These red LEDs were bright enough only for use as indicators, as the light output was not enough to illuminate an area. Readouts in calculators were so small that plastic lenses were built over each digit to make them legible. Later, other colors grew widely available and also appeared in appliances and equipment. As LED materials technology grew more advanced, light output rose, while maintaining efficiency and reliability at acceptable levels. The invention and development of the high power white light LED led to use for illumination[20][21] (see list of illumination applications). Most LEDs were made in the very common 5 mm T1¾ and 3 mm T1 packages, but with rising power output, it has grown increasingly necessary to shed excess heat to maintain reliability,[22] so more complex packages have been adapted for efficient heat dissipation. Packages for state-of-the-art high power LEDs bear little resemblance to early LEDs. Illustration of Haitz's Law. Light output per LED as a function of production year, note the logarithmic scale on the vertical axis. [edit] Continuing development The first high-brightness blue LED was demonstrated by Shuji Nakamura of Nichia Corporation and was based on InGaN borrowing on critical developments in GaN nucleation on sapphire substrates and the demonstration of p-type doping of GaN which were developed by Isamu Akasaki and H. Amano in Nagoya. In 1995, Alberto Barbieri at the Cardiff University Laboratory (GB) investigated the efficiency and reliability of high-brightness LEDs and demonstrated a very impressive result by using a transparent contact made of indium tin oxide (ITO) on (AlGaInP/GaAs) LED. The existence of blue LEDs and high efficiency LEDs quickly led to the development of the first white LED, which employed a Y3Al5O12:Ce, or "YAG", phosphor coating to mix yellow (down-converted) light with blue to produce light that appears white. Nakamura was awarded the 2006 Millennium Technology Prize for his invention.[23] The development of LED technology has caused their efficiency and light output to rise exponentially, with a doubling occurring about every 36 months since the 1960s, in a way similar to Moore's law. The advances are generally attributed to the parallel development of other semiconductor technologies and advances in optics and material science. This trend is normally called Haitz's Law after Dr. Roland Haitz. [24] In February 2008, 300 lumens of visible light per watt luminous efficacy (not per electrical watt) and warm-light emission was achieved by using nanocrystals.[25] In 2009, a process for growing gallium nitride (GaN) LEDs on silicon has been reported. Epitaxy costs could be reduced by up to 90% using six-inch silicon wafers instead of two-inch sapphire wafers.[26] [edit] Technology The inner workings of an LED I-V diagram for a diode. An LED will begin to emit light when the on-voltage is exceeded. Typical on voltages are 2–3 volts [edit] Physics Like a normal diode, the LED consists of a chip of semiconducting material doped with impurities to create a p-n junction. As in other diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction. Charge-carriers—electrons and holes—flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The wavelength of the light emitted, and thus its color depends on the band gap energy of the materials forming the p-n junction. In silicon or germanium diodes, the electrons and holes recombine by a non-radiative transition which produces no optical emission, because these are indirect band gap materials. The materials used for the LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light. LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors. LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface. P-type substrates, while less common, occur as well. Many commercial LEDs, especially GaN/InGaN, also use sapphire substrate. Most materials used for LED production have very high refractive indices. This means that much light will be reflected back into the material at the material/air surface interface. Thus, light extraction in LEDs is an important aspect of LED production, subject to much research and development. [edit] Refractive Index Idealized example of light emission cones in a semiconductor, for a single point-source emission zone. The left illustration is for a fully translucent wafer, while the right illustration shows the half-cones formed when the bottom layer is fully opaque. The light is actually emitted equally in all directions from the point-source, so the areas between the cones shows the large amount of trapped light energy that is wasted as heat.[27] The light emission cones of a real LED wafer are far more complex than a single point-source light emission. Typically the light emission zone is a 2D plane between the wafers. Across this 2D plane, there is effectively a separate set of emission cones for every atom. Drawing the billions of overlapping cones is impossible, so this is a simplified diagram showing the extents of all the emission cones combined. The larger side cones are clipped to show the interior features and reduce image complexity; they would extend to the opposite edges of the 2D emission plane. Bare uncoated semiconductors such as silicon exhibit a very high refractive index relative to open air, which prevents passage of photons at sharp angles relative to the air-contacting surface of the semiconductor. This property affects both the light-emission efficiency of LEDs as well as the light-absorption efficiency of photovoltaic cells. The refractive index of silicon is 4.24, while air is 1.00002926[28] Generally a flat-surfaced uncoated LED semiconductor chip will only emit light perpendicular to the semiconductor's surface, and a few degrees to the side, in a cone shape referred to as the light cone, cone of light,[29] or the escape cone.[27] The maximum angle of incidence is referred to as the critical angle. When this angle is exceeded photons no longer penetrate the semiconductor, but are instead reflected both internally inside the semiconductor crystal, and externally off the surface of the crystal as if it were a mirror.[27] Internal reflections can escape through other crystalline faces, if the incidence angle is low enough and the crystal is sufficiently transparent to not re-absorb the photon emission. But for a simple square LED with 90-degree angled surfaces on all sides, the faces all act as equal angle mirrors. In this case the light can not escape and is lost as waste heat in the crystal.[27] A convoluted chip surface with angled facets similar to a jewel or fresnel lens can increase light output by allowing light to be emitted perpendicular to the chip surface while far to the sides of the photon emission point.[30] The ideal shape of a semiconductor with maximum light output would be a microsphere with the photon emission occurring at the exact center, with electrodes penetrating to the center to contact at the emission point. All light rays emanating from the center would be perpendicular to the entire surface of the sphere, resulting in no internal reflections. A hemispherical semiconductor would also work, with the flat back-surface serving as a mirror to back-scattered photons.[31] [edit] Transition coatings Many LED semiconductor chips are potted in clear or colored molded plastic shells. The plastic shell has three purposes: 1. Mounting the semiconductor chip in devices is easier to accomplish. 2. The tiny fragile electrical wiring is physically supported and protected from damage 3. The plastic acts as a refractive intermediary between the relatively high-index semiconductor and low-index open air.[32] The third feature helps to boost the light emission from the semiconductor by acting as a diffusing lens, allowing light to be emitted at a much higher angle of incidence from the light cone, than the bare chip is able to emit alone. [edit] Efficiency and operational parameters Typical indicator LEDs are designed to operate with no more than 30–60 milliwatts [mW] of electrical power. Around 1999, Philips Lumileds introduced power LEDs capable of continuous use at one watt [W]. These LEDs used much larger semiconductor die sizes to handle the large power inputs. Also, the semiconductor dies were mounted onto metal slugs to allow for heat removal from the LED die. One of the key advantages of LED-based lighting is its high efficiency, as measured by its light output per unit power input. White LEDs quickly matched and overtook the efficiency of standard incandescent lighting systems. In 2002, Lumileds made five-watt LEDs available with a luminous efficacy of 18–22 lumens per watt [lm/W]. For comparison, a conventional 60–100 W incandescent light bulb emits around 15 lm/W, and standard fluorescent lights emit up to 100 lm/W. A recurring problem is that efficiency falls sharply with rising current. This effect is known as droop and effectively limits the light output of a given LED, raising heating more than light output for higher current.[33][34][35] In September 2003, a new type of blue LED was demonstrated by the company Cree Inc. to provide 24 mW at 20 milliamperes [mA]. This produced a commercially packaged white light giving 65 lm/W at 20 mA, becoming the brightest white LED commercially available at the time, and more than four times as efficient as standard incandescents. In 2006, they demonstrated a prototype with a record white LED luminous efficacy of 131 lm/W at 20 mA. Also, Seoul Semiconductor plans for 135 lm/W by 2007 and 145 lm/W by 2008,[36] which would be nearing an order of magnitude improvement over standard incandescents and better than even standard fluorescents. Nichia Corporation has developed a white LED with luminous efficacy of 150 lm/W at a forward current of 20 mA.[37] Practical general lighting needs high-power LEDs, of one watt or more. Typical operating currents for such devices begin at 350 mA. Note that these efficiencies are for the LED chip only, held at low temperature in a lab. Lighting works at higher temperature and with drive circuit losses, so efficiencies are much lower. United States Department of Energy (DOE) testing of commercial LED lamps designed to replace incandescent lamps or CFLs showed that average efficacy was still about 46 lm/W in 2009 (tested performance ranged from 17 lm/W to 79 lm/W).[38] Cree issued a press release on February 3, 2010 about a laboratory prototype LED achieving 208 lumens per watt at room temperature. The correlated color temperature was reported to be 4579 K.[39] [edit] Lifetime and failure Main article: List of LED failure modes Solid state devices such as LEDs are subject to very limited wear and tear if operated at low currents and at low temperatures. Many of the LEDs made in the 1970s and 1980s are still in service today. Typical lifetimes quoted are 25,000 to 100,000 hours but heat and current settings can extend or shorten this time significantly. [40] The most common symptom of LED (and diode laser) failure is the gradual lowering of light output and loss of efficiency. Sudden failures, although rare, can occur as well. Early red LEDs were notable for their short lifetime. With the development of high-power LEDs the devices are subjected to higher junction temperatures and higher current densities than traditional devices. This causes stress on the material and may cause early light-output degradation. To quantitatively classify lifetime in a standardized manner it has been suggested to use the terms L75 and L50 which is the time it will take a given LED to reach 75% and 50% light output respectively.[41] Like other lighting devices, LED performance is temperature dependent. Most manufacturers’ published ratings of LEDs are for an operating temperature of 25 °C. LEDs used outdoors, such as traffic signals or in-pavement signal lights, and that are utilized in climates where the temperature within the luminaire gets very hot, could result in low signal intensities or even failure.[42] LED light output actually rises at colder temperatures (leveling off depending on type at around −30C[citation needed]). Consequently, LED technology may be a good replacement in uses such as supermarket freezer lighting[43][44][45] and will last longer than other technologies. Because LEDs emit less heat than incandescent bulbs, they are an energy-efficient technology for uses such as freezers. However, because they emit little heat, ice and snow may build up on the LED luminaire in colder climates.[42] This lack of waste heat generation has been observed to cause sometimes significant problems with street traffic signals and airport runway lighting in snow-prone areas, although some research has been done to try to develop heat sink technologies to transfer heat to other areas of the luminaire.
  • brush Return to the top
  • The term brush refers to devices with bristles, wire or other filaments, used for cleaning, grooming hair, make up, painting, surface finishing and for many other purposes. Configurations include twisted-in wire (e.g. bottle brushes), cylinders and disks (with bristles spread in one face or radially). A common way of setting the bristle in the brush is the staple or anchor set brush, in which the filament is forced with a staple by the middle into a hole with a special driver and held there by the pressure against all of the walls of the hole and the portions of the staple nailed to the bottom of the hole. The staple can be replaced with a kind of anchor, which is a piece of rectangular profile wire that is anchored to the wall of the hole, like in most toothbrushes. Another way to attach the bristles to the surface can be found in the fused brush, in which instead of being inserted into a hole, a plastic fiber is welded to another plastic surface, giving the option to use different diameters of bristles in the same brush. Contents [hide] * 1 Manufacturing process of a brush handle * 2 Cleaning brushes * 3 Paintbrushes o 3.1 Decorators' brushes o 3.2 Artists' brushes + 3.2.1 Shapes + 3.2.2 Sizes + 3.2.3 Bristles + 3.2.4 Handles * 4 See also * 5 References * 6 External links [edit] Manufacturing process of a brush handle The first requirement when manufacturing a cleaning style brush is to start with the brush block. This can vary in wood type, the most commonly used handles comes from maple. Once the wood type is selected it is then cut into planks with in a certain width requirement. Throughout this process workers mark down where the cracks or knots are in the wood and draw a red line across the flaw with a special wax crayon. A laser can read this line as the planks are moved forward, cutting the line with a saw. Shortly after the blocks are cut to the appropriate length, moving on to the shaping of the block known as molding. Once the wood block is set in place for molding, a series of saws cut the block to the required thickness. A machine called the shaper follows this action. The brush handle is placed in the machine, revolving and slicing away the outside edge. This only cuts away half of the block. To keep in good profile the same actions are done to the opposite side. Each model uses a different shaper machine. The machines must stay sharp for the blocks to remain smooth and accurate. Carbide cutters are used in these machines rather than steel because carbide is much harder and more durable. [edit] Cleaning brushes Brushes used for cleaning come in various sizes. They vary in size from a that of a toothbrush, to the standard household version accompanied by a dustpan, to 36" deck brushes. There are brushes for cleaning tiny cracks and crevices and brushes for cleaning enormous warehouse floors. Brushes perform a multitude of cleaning tasks. For example, brushes lightly dust the tiniest figurine, they help scrub stains out of clothing and shoes, they remove grime from tires, and they remove the dirt and debris found on floors with the help of a dust pan. Many kinds of specialty brushes are used for cleaning vegetables, cleaning the toilet, washing glass, finishing tiles, and sanding doors. [edit] Paintbrushes "Paintbrush" redirects here. For other uses, see Paintbrush (disambiguation). Paintbrushes are used for applying ink or paint. Paintbrushes are primary used by artists for painted pictures. A special kind of drawing is the so called paintbrush-drawing, drawings only done with paintbrushes instead of pencil or pen. Paintbrush drawing by Herbert Wetterauer (Portrait of Martin Heidegger) These brushes are usually made by clamping the bristles to a handle with a ferrule. [edit] Decorators' brushes The sizes of brushes used for painting and decorating are given in mm or inches, referring to the width of the head. Common sizes are: * ⅛ in, ¼ in, ⅜ in, ½ in, ⅝ in, ¾ in, ⅞ in, 1 in, 1¼ in, 1½ in, 2 in, 2½ in, 3 in, 3½ in, 4 in. * 10 mm, 20 mm, bob 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm. Bristles may be natural or synthetic. If the filaments are synthetic, they could be made of polyester, nylon or a blend of nylon and polyester. Filaments can be hollow or solid and can be tapered or untapered. Brushes with tapered filaments give a smoother finish. [1] Synthetic filaments last longer than natural bristles. Natural bristles are preferred for oil-based paints and varnishes, while synthetic brushes are better for water-based paints as the bristles do not expand when wetted. [2] A decorator judges the quality of a brush based on several factors: filament retention, paint pickup, steadiness of paint release, brush marks, drag and precision painting. A chiseled brush permits the painter to cut into tighter corners and paint more precisely. [3] Handles may be wood or plastic; ferrules are metal (usually nickel-plated steel). Paintbrushes [edit] Artists' brushes Short handled brushes are for watercolor or ink painting while the long handled brushes are for oil or acrylic paint. [edit] Shapes The styles of brush tip seen most commonly are: * Round: pointed tip, long closely arranged bristles for detail * Flat: for spreading paint quickly and evenly over a surface. They will have longer hairs than their Bright counterpart. * Bright: shorter than flats. Flat brushes with short stiff bristles, good for driving paint into the weave of a canvas in thinner paint applications, as well as thicker painting styles like impasto work. * Filbert: flat brushes with domed ends. They allow good coverage and the ability to perform some detail work. * Fan: for blending broad areas of paint. * Angle: like the filbert, these are versatile and can be applied in both general painting application as well as some detail work. * Mop: a larger format brush with a rounded edge for broad soft paint application as well as for getting thinner glazes over existing drying layers of paint without damaging lower layers. * Rigger: round brushes with longish hairs, traditionally used for painting the rigging in pictures of ships. They are useful for fine lines and are versatile for both oils and watercolors. * Stippler and deer-foot stippler: short, stubby rounds * Liner: elongated rounds * Dagger * Scripts: highly elongated rounds * Egbert Types of Brushes Some other styles of brush include: * Sumi: Similar in style to certain watercolor brushes,also with a generally thick wooden or bamboo handle and a broad soft hair brush that when wetted should form a fine tip. Also spelled Sumi-e. * Hake: An Asian style of brush with a large broad wooden handle and an extremely fine soft hair used in counterpoint to traditional Sumi brushes for covering large areas. Often made of goat hair. * Spotter: Round brushes with just a few short bristles. These brushes are commonly used in spotting photographic prints. * Stencil: A round brush with a flat top used on stencils to ensure the bristled don't get underneath. Also used to create texture. [edit] Sizes Artists' brushes are usually given numbered sizes, although there is no exact standard for their physical dimensions. From smallest to largest, the sizes are: * 10/0, 7/0 (also written 0000000), 6/0, 5/0, 4/0, 000, 00, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 20, 22, 24, 25, 26, 28, 30. Brushes as fine as 30/0 are manufactured by major companies, but are not a common size. Sizes 000 to 20 are most common. [edit] Bristles Types include: * watercolor brushes which are usually made of sable, synthetic sable or nylon; * oil painting brushes which are usually made of sable or bristle; * acrylic brushes which are almost entirely nylon or synthetic. Turpentine or thinners used in oil painting can destroy some types of synthetic brushes. However, innovations in synthetic bristle technology have produced solvent resistant synthetic bristles suitable for use in all media. Natural hair, squirrel, badger or sable are used by watercolorists due to their superior ability to absorb and hold water. Bristles may be natural — either soft hair or hog bristle — or synthetic. * Soft hair brushes are made from Kolinsky sable or ox hair (sabeline); or more rarely, squirrel, pony, goat, mongoose or badger. Cheaper hair is sometimes called camel hair, although it does not come from camels. * Hog bristle (often called China bristle or Chungking bristle) is stiffer and stronger than soft hair. It may be bleached or unbleached. * Synthetic bristles are made of special multi-diameter extruded nylon filament, or Taklon, multi-diameter polyester. and are becoming ever more popular with the development of new water based paints. [edit] Handles Artists' brush handles are commonly wooden but can also be made of molded plastic. Many mass-produced handles are made of unfinished raw wood; better quality handles are of seasoned hardwood. The wood is sealed and lacquered to give the handle a high-gloss, waterproof finish that reduces soiling and swelling. Metal ferrules may be of aluminum, nickel, copper, or nickel-plated steel. Quill ferrules are also found: these give a different "feel" to the brush.
  • aromatherapy Return to the top
  • Aromatherapy is a form of alternative medicine that uses volatile plant materials, known as essential oils, and other aromatic compounds for the purpose of altering a person's mind, mood, cognitive function or health. Some essential oils such as tea tree[1] have demonstrated anti-microbial effects, but there is still a lack of clinical evidence demonstrating efficacy against bacterial, fungal, or viral infections. Evidence for the efficacy of aromatherapy in treating medical conditions remains poor, with a particular lack of studies employing rigorous methodology,[2] however some evidence exists that essential oils may have therapeutic potential.[3] Contents [hide] * 1 History * 2 Modes of application * 3 Materials * 4 Theory * 5 Choice and purchase * 6 Popular uses * 7 Efficacy * 8 Safety concerns * 9 References * 10 Further reading * 11 External links [edit] History Aromatherapy may have origins in antiquity with the use of infused aromatic oils, made by macerating dried plant material in fatty oil, heating and then filtering. Many such oils are described by Dioscorides, along with beliefs of the time regarding their healing properties, in his De Materia Medica, written in the first century.[4] Distilled essential oils have been employed as medicines since the invention of distillation in the eleventh century,[5] when Avicenna isolated essential oils using steam distillation.[6] The concept of aromatherapy was first mooted by a small number of European scientists and doctors, in about[weasel words] 1907. In 1937, the word first appeared in print in a French book on the subject: Aromathérapie: Les Huiles Essentielles, Hormones Végétales by René-Maurice Gattefossé, a chemist. An English version was published in 1993.[7] In 1910, Gattefossé burned a hand very badly in a laboratory explosion. The hand developed gas gangrene, which he successfully, and intentionally, treated with lavender oil. [8] A French surgeon, Jean Valnet, pioneered the medicinal uses of essential oils, which he used as antiseptics in the treatment of wounded soldiers during World War II.[9] [edit] Modes of application The modes of application of aromatherapy include: * Aerial diffusion: for environmental fragrancing or aerial disinfection * Direct inhalation: for respiratory disinfection, decongestion, expectoration as well as psychological effects * Topical applications: for general massage, baths, compresses, therapeutic skin care [edit] Materials Some of the materials employed include: * Absolutes: Fragrant oils extracted primarily from flowers or delicate plant tissues through solvent or supercritical fluid extraction (e.g., rose absolute). The term is also used to describe oils extracted from fragrant butters, concretes, and enfleurage pommades using ethanol. * Carrier oils: Typically oily plant base triacylglycerides that dilute essential oils for use on the skin (e.g., sweet almond oil). * Essential oils: Fragrant oils extracted from plants chiefly through steam distillation (e.g., eucalyptus oil) or expression (grapefruit oil). However, the term is also occasionally used to describe fragrant oils extracted from plant material by any solvent extraction. * Herbal distillates or hydrosols: The aqueous by-products of the distillation process (e.g., rosewater). There are many herbs that make herbal distillates and they have culinary uses, medicinal uses and skin care uses[citation needed]. Common herbal distillates are chamomile, rose, and lemon balm. * Infusions: Aqueous extracts of various plant material (e.g., infusion of chamomile). * Phytoncides: Various volatile organic compounds from plants that kill microbes[citation needed]. Many terpene-based fragrant oils and sulfuric compounds from plants in the genus "Allium" are phytoncides[citation needed], though the latter are likely less commonly used in aromatherapy due to their disagreeable odors. * Vaporizer (Volatized) Raw Herbs: Typically higher oil content plant based materials dried, crushed, and heated to extract and inhale the aromatic oil vapors in a direct inhalation modality. [edit] Theory Aromatherapy is the treatment or prevention of disease by use of essential oils. Other stated uses include pain and anxiety reduction, enhancement of energy and short-term memory, relaxation, hair loss prevention, and reduction of eczema-induced itching. [10][11] Two basic mechanisms are offered to explain the purported effects. One is the influence of aroma on the brain, especially the limbic system through the olfactory system.[12] The other is the direct pharmacological effects of the essential oils.[13] While precise knowledge of the synergy between the body and aromatic oils is often claimed by aromatherapists, the efficacy of aromatherapy remains unproven. However, some preliminary clinical studies of aromatherapy in combination with other techniques show positive effects. Aromatherapy does not cure conditions, but helps the body to find a natural way to cure itself and improve immune response.[14][15] In the English-speaking world, practitioners tend to emphasize the use of oils in massage[citation needed]. Aromatherapy tends to be regarded[by whom?] as a complementary modality at best and a pseudoscientific fraud at worst.[16] [edit] Choice and purchase Oils with standardized content of components (marked FCC, for Food Chemical Codex) are required to contain a specified amount of certain aroma chemicals that normally occur in the oil[citation needed]. But there is no law that the chemicals cannot be added in synthetic form in order to meet the criteria established by the FCC for that oil[citation needed]. For instance, lemongrass essential oil must contain 75% aldehyde[citation needed] to meet the FCC profile for that oil, but that aldehyde can come from a chemical refinery instead of from lemongrass. To say that FCC oils are "food grade", then, makes them seem natural when, in fact, they are not necessarily so. Undiluted essential oils suitable for aromatherapy are termed therapeutic grade, but in countries where the industry is unregulated, therapeutic grade is based on industry consensus and is not a regulatory category[citation needed]. Some aromatherapists take advantage of this situation to make misleading claims about the origin and even content of the oils they use. Likewise, claims that an oil's purity is vetted by mass spectrometry or gas chromatography have limited value, since all such testing can do is show that various chemicals occur in the oil[citation needed]. Many[which?] of the chemicals that occur naturally in essential oils are manufactured by the perfume industry and adulterate essential oils because they are cheaper. There is no way to distinguish between these synthetic additives and the naturally occurring chemicals. The best instrument for determining whether or not an essential oil is adulterated is an educated nose{[which?]. Many people[who?] can distinguish between natural and synthetic scents, but it takes experience[citation needed]. [edit] Popular uses * Lemon oil is uplifting and anti-stress/anti-depressant. In a Japanese study, lemon essential oil in vapour form has been found to reduce stress in mice.[17] Research at The Ohio State University indicates that Lemon oil aroma may enhance one's mood, and help with relaxation.[18] * Thyme oil[19] [edit] Efficacy Some benefits that have been linked to aromatherapy, such as relaxation and clarity of mind, may arise from the placebo effect rather than from any actual physiological effect. The consensus among most medical professionals is that while some aromas have demonstrated effects on mood and relaxation and may have related benefits for patients, there is currently insufficient evidence to support the claims made for aromatherapy.[20] Scientific research on the cause and effects of aromatherapy is limited, although in vitro testing has revealed some antibacterial and antiviral effects.[21] [22] There is no evidence of any long-term results from an aromatherapy massage other than the pleasure achieved from a pleasant-smelling massage.[23] A few double blind studies in the field of clinical psychology relating to the treatment of severe dementia have been published.[24][25] Essential oils have a demonstrated efficacy in dental mouthwash products.[26] Skeptical literature suggests that aromatherapy is based on the anecdotal evidence of its benefits rather than proof that aromatherapy can cure diseases. Scientists and medical professionals acknowledge that aromatherapy has limited scientific support, but critics argue that the claims of most aromatherapy practitioners go beyond the data, and/or that the studies are neither adequately controlled nor peer reviewed. Some proponents[who?] of aromatherapy believe that the claimed effect of each type of oil is not caused by the chemicals in the oil interacting with the senses, but because the oil contains a distillation of the "life force" of the plant from which it is derived that will "balance the energies" of the body and promote healing or well-being by purging negative vibrations from the body's energy field. Arguing that there is no scientific evidence that healing can be achieved, and that the claimed "energies" even exist, many skeptics reject this form of aromatherapy as pseudoscience. [edit] Safety concerns In addition, there are potential safety concerns. Because essential oils are highly concentrated they can irritate the skin when used neat, that is undiluted.{{Citation: J Grassman and E F Elstner, article "Essential Oils", in Encyclopedia of Food Sciences and Nutrition 2nd ed., edited by Benjamin Caballero, Luiz C Trugo, Paul M Finglas, Academic Press, 1973, ISBN 0-12-227055-X}} Therefore, they are normally diluted with a carrier oil for topical application. Phototoxic reactions may occur with citrus peel oils such as lemon or lime.[27] Also, many essential oils have chemical components that are sensitisers (meaning that they will after a number of uses cause reactions on the skin, and more so in the rest of the body). Some of the chemical allergies could even be caused by pesticides, if the original plants are cultivated.[28][29] Some oils can be toxic to some domestic animals, with cats being particularly prone.[30][31] Two common oils, lavender and tea tree, have been implicated in causing gynaecomastia, an abnormal breast tissue growth, in prepubescent boys, although the report which cites this potential issue is based on observations of only three boys (and so is not a scientific study), and two of those boys were significantly above average in weight for their age, thus already prone to gynaecomastia.[32] A child hormone specialist at the University of Cambridge claimed "... these oils can mimic estrogens" and "people should be a little bit careful about using these products."[33] The study has been criticised on many different levels by many authorities. The Aromatherapy Trade Council of the UK has issued a rebuttal [34] The Australian Tea Tree Association, a group that promotes the interests of Australian tea tree oil producers, exporters and manufacturers issued a letter that questioned the study and called on the New England Journal of Medicine for a retraction (ATTIA). [35] The New England Journal of Medicine has so far not replied and has not retracted the study. As with any bioactive substance, an essential oil that may be safe for the general public could still pose hazards for pregnant and lactating women. While some advocate the ingestion of essential oils for therapeutic purposes, licensed aromatherapy professionals do not recommend self prescription due the highly toxic nature of some essential oil. Some very common oils like Eucalyptus are extremely toxic when taken internally. Doses as low as one teaspoon has been reported to cause clinically significant symptoms and severe poisoning can occur after ingestion of 4 to 5 ml.[36] A few reported cases of toxic reactions like liver damage and seizures have occurred after ingestion of sage, hyssop, thuja, and cedar.[37] Accidental ingestion may happen when oils are not kept out of reach of children. Oils both ingested and applied to the skin can potentially have negative interaction with conventional medicine. For example, the topical use of methyl salicylate heavy oils like Sweet Birch and Wintergreen may cause hemorrhaging in users taking the anticoagulant Warfarin. Adulterated oils may also pose problems depending on the type of substance used. [edit] References 1. ^ Carson CF, Hammer KA, Riley TV (January 2006). "Melaleuca alternifolia (Tea Tree) oil: a review of antimicrobial and other medicinal properties". Clinical Microbiology Reviews 19 (1): 50–62. doi:10.1128/CMR.19.1.50-62.2006. PMID 16418522. 2. ^ van der Watt G, Janca A (August 2008). "Aromatherapy in nursing and mental health care". Contemporary Nurse 30 (1): 69–75. doi:10.5555/conu.673.30.1.69. PMID 19072192. 3. ^ Edris AE (April 2007). "Pharmaceutical and therapeutic potentials of essential oils and their individual volatile constituents: a review". Phytotherapy Research 21 (4): 308–23. doi:10.1002/ptr.2072. PMID 17199238. 4. ^ Gunther, R.T. (ed.) (1959). The Greek Herbal of Dioscorides (translated by John Goodyer in 1655). New York: Hafner Publishing. OCLC 3570794 5. ^ Forbes R.J. (1970). A short history of the art of distillation. Leiden: E.J. Brill. OCLC 2559231 6. ^ Ericksen, Marlene (2000). Healing With Aromatherapy. New York: McGraw-Hill. p. 9. ISBN 0-658-00382-8. 7. ^ Gattefossé, R.-M., & Tisserand, R. (1993). Gattefossé's aromatherapy. Saffron Walden: C.W. Daniel. ISBN 0-85207-236-8 8. ^ "Aromatherapy". University of Maryland Medical Center. http://www.umm.edu/altmed/articles/aromatherapy-000347.htm. Retrieved 24 October 2010. 9. ^ Valnet, J., & Tisserand, R. (1990). The practice of aromatherapy: A classic compendium of plant medicines & their healing properties. Rochester, VT: Healing Arts Press. ISBN 0-89281-398-9 10. ^ Jennifer A. Kingston (28 July 2010). "Nostrums: Aromatherapy Rarely Stands Up to Testing". http://www.nytimes.com/2010/07/29/fashion/29skin.html. Retrieved 29 December 2010. 11. ^ Eric Nagourney (11 March 2008). "Skin Deep: In Competition for your Nose". http://www.nytimes.com/2008/03/11/health/research/11nost.html. Retrieved 29 December 2010. 12. ^ "The Power of Smell". Serendip. http://www.serendip.brynmawr.edu/exchange/node/1887. Retrieved 24 October 2010. [dead link] 13. ^ Prabuseenivasan S, Jayakumar M, Ignacimuthu S (2006). "In vitro antibacterial activity of some plant essential oils". BMC Complementary and Alternative Medicine 6: 39. doi:10.1186/1472-6882-6-39. PMID 17134518. 14. ^ Kim HJ (June 2007). "[Effect of aromatherapy massage on abdominal fat and body image in post-menopausal women"] (in Korean). Taehan Kanho Hakhoe Chi 37 (4): 603–12. PMID 17615482. http://www.kan.or.kr/new/kor/sub3/sub3_1.php?start=view&year=2007&issue=4&volume=37&spage=603. 15. ^ Rho KH, Han SH, Kim KS, Lee MS (December 2006). "Effects of aromatherapy massage on anxiety and self-esteem in korean elderly women: a pilot study". The International Journal of Neuroscience 116 (12): 1447–55. doi:10.1080/00207450500514268. PMID 17145679. 16. ^ Barrett, Stephen. "Aromatherapy: Making Dollars out of Scents", Science & Pseudoscience Review in Mental Health. Scientific Review of Mental Health Practice (SRMHP). Retrieved on 2009-08-10. 17. ^ "Lemon oil vapor causes an anti-stress effect via modulating the 5-HT and DA activities in mice.". PubMed.gov. 2006-06-15. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16780969&query_hl=6&itool=pubmed_docsum. Retrieved 2007-04-26. 18. ^ Ohio State University Research, March 3, 2008 Study is published in the March 2008 issue of the journal Psychoneuroendocrinology 19. ^ Antimicrobial and antiplasmid activities of essential oils. 20. ^ http://www.cancer.gov/cancertopics/pdq/cam/aromatherapy/HealthProfessional/page3 cancer.gov - Aromatherapy and Essential Oils 21. ^ "Antibacterial and antifungal properties of essential oils". Curr Med Chem. 10 (10): 813–29. 2003 May.. doi:10.2174/0929867033457719. PMID 12678685. 22. ^ "Essential oils of aromatic plants with antibacterial, antifungal, antiviral, and cytotoxic properties--an overview.". Forsch Komplementmed. 2 (2): 79–90. 2009 Apr;16. Epub 3 April 2009.. doi:10.1159/000207196. PMID 19420953. 23. ^ http://pmj.sagepub.com/cgi/content/abstract/18/2/87 A randomized controlled trial of aromatherapy massage in a hospice setting 24. ^ Ballard CG, O'Brien JT, Reichelt K, Perry EK (July 2002). "Aromatherapy as a safe and effective treatment for the management of agitation in severe dementia: the results of a double-blind, placebo-controlled trial with Melissa". J Clin Psychiatry 63 (7): 553–8. PMID 12143909. 25. ^ Holmes C, Hopkins V, Hensford C, MacLaughlin V, Wilkinson D, Rosenvinge H. (April 2002). "Lavender oil as a treatment for agitated behaviour in severe dementia: a placebo controlled study". Int J Geriatr Psychiatry 17 (4): 305–8.. doi:10.1002/gps.593. PMID 11994882. 26. ^ "The long-term effect of a mouthrinse containing essential oils on dental plaque and gingivitis: a systematic review". Periodontol. 78 (7): 1218–28. 2007 July. doi:10.1902/jop.2007.060269. PMID 17608576 : 17608576. 27. ^ http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1312240 Hyperpigmented macules and streaks 28. ^ Edwards, J.; Bienvenu, F.E. (1999). "Investigations into the use of flame and the herbicide, paraquat, to control peppermint rust in north-east Victoria, Australia". Australasian Plant Pathology 28 (3): 212–224. doi:10.1071/AP99036. 29. ^ Adamovic, D.S. et al.. "Variability of herbicide efficiency and their effect upon yield and quality of peppermint (Mentha X Piperital L.)". http://www.actahort.org/books/249/249_8.htm. Retrieved 6 June 2009. 30. ^ The Lavender Cat - Cats and Essential Oil Safety 31. ^ K. Bischoff, F. Guale (1998). "Australian tea tree (Melaleuca alternifolia) Oil Poisoning in three purebred cats" (–Scholar search). Journal of Veterinary Diagnostic Investigation 10 (108). Archived from the original on October 15, 2006. http://web.archive.org/web/20061015234207/http://www.vet-task-force.com/Abstract-tea-tree-oil.htm. Retrieved 2006-10-17. [dead link] 32. ^ Henley, D. V.; Lipson, N; Korach, KS; Bloch, CA (2007). "Prepubertal gynecomastia linked to lavender and tea tree oils". New England Journal of Medicine 356 (5): 479–85. doi:10.1056/NEJMoa064725. PMID 17267908. http://content.nejm.org/cgi/content/abstract/356/5/479. 33. ^ "Oils make male breasts develop". BBC News Online (London). 1 February 2007. http://news.bbc.co.uk/2/hi/health/6318043.stm. Retrieved 2007-09-09. 34. ^ 'NEITHER LAVENDER OIL NOR TEA TREE OIL CAN BE LINKED TO BREAST GROWTH IN YOUNG BOYS' 35. ^ 'ATTIA refutes gynecomastia link', Article Date: 21 February 2007 36. ^ Eucalyptus oil (PIM 031) 37. ^ Millet Y, Jouglard J, Steinmetz MD, Tognetti P, Joanny P, Arditti J. (December 1981). "Toxicity of some essential plant oils. Clinical and experimental study". Clin Toxicol. 18 (12): 1485–98. doi:10.3109/15563658108990357. PMID 7333081. [edit] Further reading * Burke, L., & Chambers, P. (1995). The very essence: A guide to aromatherapy. Silver Link. OCLC 60274302 * Lis-Balchin, Maria (2006). Aromatherapy science: A guide for healthcare professionals. London: Pharmaceutical Press. ISBN 0-85369-578-4 * Schnaubelt, Kurt (1998). Advanced aromatherapy: The science of essential oil therapy. Rochester, VT: Healing Arts Press. ISBN 0-89281-743-7 * Schnaubelt, Kurt (1999). Medical aromatherapy: Healing with essential oils. Berkeley, CA: Frog. ISBN 1-883319-69-2 * Valnet, Jean; & Tisserand, Robert (1990). The practice of aromatherapy: A classic compendium of plant medicines & their healing properties. Rochester, VT: Healing Arts Press. ISBN 0-89281-398-9 * National Research Council (2003). Food Chemicals Codex. Washington D.C.: National Academy Press. ISBN 0309088666. * Wanjek, Christopher (2003). Bad medicine: Misconceptions and misuses revealed, from distance healing to vitamin O. New York: J. Wiley. ISBN 0-471-43499-X * Valnet, Jean; & Tisserand, Robert (1982). The practice of aromatherapy. Saffron Walden: Danie
  • Aromatherapy is a form of alternative medicine that uses volatile plant materials, known as essential oils, and other aromatic compounds for the purpose of altering a person's mind, mood, cognitive function or health. Since some essential oils such as tea tree[1] have demonstrated anti-microbial effects, it has been suggested that they may be useful for the treatment of infectious diseases. Evidence for the efficacy of aromatherapy in treating medical conditions remains poor, with a particular lack of studies employing rigorous methodology,[2] however some evidence exists that essential oils may have therapeutic potential.[3] Contents [hide] * 1 History * 2 Modes of application * 3 Materials * 4 Theory * 5 Choice and purchase * 6 Popular uses * 7 Efficacy * 8 Safety concerns * 9 References * 10 Further reading * 11 External links [edit] History Aromatherapy may have origins in antiquity with the use of infused aromatic oils, made by macerating dried plant material in fatty oil, heating and then filtering. Many such oils are described by Dioscorides, along with beliefs of the time regarding their healing properties, in his De Materia Medica, written in the first century.[4] Distilled essential oils have been employed as medicines since the invention of distillation in the eleventh century,[5] when Avicenna isolated essential oils using steam distillation.[6] The concept of aromatherapy was first mooted by a small number of European scientists and doctors, in about[weasel words] 1907. In 1937, the word first appeared in print in a French book on the subject: Aromathérapie: Les Huiles Essentielles, Hormones Végétales by René-Maurice Gattefossé, a chemist. An English version was published in 1993.[7] In 1910, Gattefossé burned a hand very badly in a laboratory explosion. The hand developed gas gangrene, which he successfully, and intentionally, treated with lavender oil. [8] A French surgeon, Jean Valnet, pioneered the medicinal uses of essential oils, which he used as antiseptics in the treatment of wounded soldiers during World War II.[9] [edit] Modes of application The modes of application of aromatherapy include: * Aerial diffusion: for environmental fragrancing or aerial disinfection * Direct inhalation: for respiratory disinfection, decongestion, expectoration as well as psychological effects * Topical applications: for general massage, baths, compresses, therapeutic skin care [edit] Materials Some of the materials employed include: * Absolutes: Fragrant oils extracted primarily from flowers or delicate plant tissues through solvent or supercritical fluid extraction (e.g., rose absolute). The term is also used to describe oils extracted from fragrant butters, concretes, and enfleurage pommades using ethanol. * Carrier oils: Typically oily plant base triacylglycerides that dilute essential oils for use on the skin (e.g., sweet almond oil). * Essential oils: Fragrant oils extracted from plants chiefly through steam distillation (e.g., eucalyptus oil) or expression (grapefruit oil). However, the term is also occasionally used to describe fragrant oils extracted from plant material by any solvent extraction. * Herbal distillates or hydrosols: The aqueous by-products of the distillation process (e.g., rosewater). There are many herbs that make herbal distillates and they have culinary uses, medicinal uses and skin care uses[citation needed]. Common herbal distillates are chamomile, rose, and lemon balm. * Infusions: Aqueous extracts of various plant material (e.g., infusion of chamomile). * Phytoncides: Various volatile organic compounds from plants that kill microbes[citation needed]. Many terpene-based fragrant oils and sulfuric compounds from plants in the genus "Allium" are phytoncides[citation needed], though the latter are likely less commonly used in aromatherapy due to their disagreeable odors. * Vaporizer (Volatized) Raw Herbs: Typically higher oil content plant based materials dried, crushed, and heated to extract and inhale the aromatic oil vapors in a direct inhalation modality. [edit] Theory Aromatherapy is the treatment or prevention of disease by use of essential oils. Other stated uses include pain and anxiety reduction, enhancement of energy and short-term memory, relaxation, hair loss prevention, and reduction of eczema-induced itching. [10][11] Two basic mechanisms are offered to explain the purported effects. One is the influence of aroma on the brain, especially the limbic system through the olfactory system.[12] The other is the direct pharmacological effects of the essential oils.[13] While precise knowledge of the synergy between the body and aromatic oils is often claimed by aromatherapists, the efficacy of aromatherapy remains unproven. However, some preliminary clinical studies of aromatherapy in combination with other techniques show positive effects. Aromatherapy does not cure conditions, but helps the body to find a natural way to cure itself and improve immune response.[14][15] In the English-speaking world, practitioners tend to emphasize the use of oils in massage[citation needed]. Aromatherapy tends to be regarded[by whom?] as a complementary modality at best and a pseudoscientific fraud at worst.[16] [edit] Choice and purchase Oils with standardized content of components (marked FCC, for Food Chemical Codex) are required to contain a specified amount of certain aroma chemicals that normally occur in the oil[citation needed]. But there is no law that the chemicals cannot be added in synthetic form in order to meet the criteria established by the FCC for that oil[citation needed]. For instance, lemongrass essential oil must contain 75% aldehyde[citation needed] to meet the FCC profile for that oil, but that aldehyde can come from a chemical refinery instead of from lemongrass. To say that FCC oils are "food grade", then, makes them seem natural when, in fact, they are not necessarily so. Undiluted essential oils suitable for aromatherapy are termed therapeutic grade, but in countries where the industry is unregulated, therapeutic grade is based on industry consensus and is not a regulatory category[citation needed]. Some aromatherapists take advantage of this situation to make misleading claims about the origin and even content of the oils they use. Likewise, claims that an oil's purity is vetted by mass spectrometry or gas chromatography have limited value, since all such testing can do is show that various chemicals occur in the oil[citation needed]. Many[which?] of the chemicals that occur naturally in essential oils are manufactured by the perfume industry and adulterate essential oils because they are cheaper. There is no way to distinguish between these synthetic additives and the naturally occurring chemicals. The best instrument for determining whether or not an essential oil is adulterated is an educated nose{[which?]. Many people[who?] can distinguish between natural and synthetic scents, but it takes experience[citation needed]. [edit] Popular uses * Lemon oil is uplifting and anti-stress/anti-depressant. In a Japanese study, lemon essential oil in vapour form has been found to reduce stress in mice.[17] Research at The Ohio State University indicates that Lemon oil aroma may enhance one's mood, and help with relaxation.[18] * Thyme oil[19] [edit] Efficacy Some benefits that have been linked to aromatherapy, such as relaxation and clarity of mind, may arise from the placebo effect rather than from any actual physiological effect. The consensus among most medical professionals is that while some aromas have demonstrated effects on mood and relaxation and may have related benefits for patients, there is currently insufficient evidence to support the claims made for aromatherapy.[20] Scientific research on the cause and effects of aromatherapy is limited, although in vitro testing has revealed some antibacterial and antiviral effects.[21] [22] There is no evidence of any long-term results from an aromatherapy massage other than the pleasure achieved from a pleasant-smelling massage.[23] A few double blind studies in the field of clinical psychology relating to the treatment of severe dementia have been published.[24][25] Essential oils have a demonstrated efficacy in dental mouthwash products.[26] Skeptical literature suggests that aromatherapy is based on the anecdotal evidence of its benefits rather than proof that aromatherapy can cure diseases. Scientists and medical professionals acknowledge that aromatherapy has limited scientific support, but critics argue that the claims of most aromatherapy practitioners go beyond the data, and/or that the studies are neither adequately controlled nor peer reviewed. Some proponents[who?] of aromatherapy believe that the claimed effect of each type of oil is not caused by the chemicals in the oil interacting with the senses, but because the oil contains a distillation of the "life force" of the plant from which it is derived that will "balance the energies" of the body and promote healing or well-being by purging negative vibrations from the body's energy field. Arguing that there is no scientific evidence that healing can be achieved, and that the claimed "energies" even exist, many skeptics reject this form of aromatherapy as pseudoscience. [edit] Safety concerns In addition, there are potential safety concerns. Because essential oils are highly concentrated they can irritate the skin when used neat, that is undiluted.{{Citation: J Grassman and E F Elstner, article "Essential Oils", in Encyclopedia of Food Sciences and Nutrition 2nd ed., edited by Benjamin Caballero, Luiz C Trugo, Paul M Finglas, Academic Press, 1973, ISBN 0-12-227055-X}} Therefore, they are normally diluted with a carrier oil for topical application. Phototoxic reactions may occur with citrus peel oils such as lemon or lime.[27] Also, many essential oils have chemical components that are sensitisers (meaning that they will after a number of uses cause reactions on the skin, and more so in the rest of the body). Some of the chemical allergies could even be caused by pesticides, if the original plants are cultivated.[28][29] Some oils can be toxic to some domestic animals, with cats being particularly prone.[30][31] Two common oils, lavender and tea tree, have been implicated in causing gynaecomastia, an abnormal breast tissue growth, in prepubescent boys, although the report which cites this potential issue is based on observations of only three boys (and so is not a scientific study), and two of those boys were significantly above average in weight for their age, thus already prone to gynaecomastia.[32] A child hormone specialist at the University of Cambridge claimed "... these oils can mimic estrogens" and "people should be a little bit careful about using these products."[33] The study has been criticised on many different levels by many authorities. The Aromatherapy Trade Council of the UK has issued a rebuttal [34] The Australian Tea Tree Association, a group that promotes the interests of Australian tea tree oil producers, exporters and manufacturers issued a letter that questioned the study and called on the New England Journal of Medicine for a retraction (ATTIA). [35] The New England Journal of Medicine has so far not replied and has not retracted the study. As with any bioactive substance, an essential oil that may be safe for the general public could still pose hazards for pregnant and lactating women. While some advocate the ingestion of essential oils for therapeutic purposes, licensed aromatherapy professionals do not recommend self prescription due the highly toxic nature of some essential oil. Some very common oils like Eucalyptus are extremely toxic when taken internally. Doses as low as one teaspoon has been reported to cause clinically significant symptoms and severe poisoning can occur after ingestion of 4 to 5 ml.[36] A few reported cases of toxic reactions like liver damage and seizures have occurred after ingestion of sage, hyssop, thuja, and cedar.[37] Accidental ingestion may happen when oils are not kept out of reach of children. Oils both ingested and applied to the skin can potentially have negative interaction with conventional medicine. For example, the topical use of methyl salicylate heavy oils like Sweet Birch and Wintergreen may cause hemorrhaging in users taking the anticoagulant Warfarin. Adulterated oils may also pose problems depending on the type of substance used. [edit] References 1. ^ Carson CF, Hammer KA, Riley TV (January 2006). "Melaleuca alternifolia (Tea Tree) oil: a review of antimicrobial and other medicinal properties". Clinical Microbiology Reviews 19 (1): 50–62. doi:10.1128/CMR.19.1.50-62.2006. PMID 16418522. 2. ^ van der Watt G, Janca A (August 2008). "Aromatherapy in nursing and mental health care". Contemporary Nurse 30 (1): 69–75. doi:10.5555/conu.673.30.1.69. PMID 19072192. 3. ^ Edris AE (April 2007). "Pharmaceutical and therapeutic potentials of essential oils and their individual volatile constituents: a review". Phytotherapy Research 21 (4): 308–23. doi:10.1002/ptr.2072. PMID 17199238. 4. ^ Gunther, R.T. (ed.) (1959). The Greek Herbal of Dioscorides (translated by John Goodyer in 1655). New York: Hafner Publishing. OCLC 3570794 5. ^ Forbes R.J. (1970). A short history of the art of distillation. Leiden: E.J. Brill. OCLC 2559231 6. ^ Ericksen, Marlene (2000). Healing With Aromatherapy. New York: McGraw-Hill. p. 9. ISBN 0-658-00382-8. 7. ^ Gattefossé, R.-M., & Tisserand, R. (1993). Gattefossé's aromatherapy. Saffron Walden: C.W. Daniel. ISBN 0-85207-236-8 8. ^ "Aromatherapy". University of Maryland Medical Center. http://www.umm.edu/altmed/articles/aromatherapy-000347.htm. Retrieved 24 October 2010. 9. ^ Valnet, J., & Tisserand, R. (1990). The practice of aromatherapy: A classic compendium of plant medicines & their healing properties. Rochester, VT: Healing Arts Press. ISBN 0-89281-398-9 10. ^ Jennifer A. Kingston (28 July 2010). "Nostrums: Aromatherapy Rarely Stands Up to Testing". http://www.nytimes.com/2010/07/29/fashion/29skin.html. Retrieved 29 December 2010. 11. ^ Eric Nagourney (11 March 2008). "Skin Deep: In Competition for your Nose". http://www.nytimes.com/2008/03/11/health/research/11nost.html. Retrieved 29 December 2010. 12. ^ "The Power of Smell". Serendip. http://www.serendip.brynmawr.edu/exchange/node/1887. Retrieved 24 October 2010. [dead link] 13. ^ Prabuseenivasan S, Jayakumar M, Ignacimuthu S (2006). "In vitro antibacterial activity of some plant essential oils". BMC Complementary and Alternative Medicine 6: 39. doi:10.1186/1472-6882-6-39. PMID 17134518. 14. ^ Kim HJ (June 2007). "[Effect of aromatherapy massage on abdominal fat and body image in post-menopausal women"] (in Korean). Taehan Kanho Hakhoe Chi 37 (4): 603–12. PMID 17615482. http://www.kan.or.kr/new/kor/sub3/sub3_1.php?start=view&year=2007&issue=4&volume=37&spage=603. 15. ^ Rho KH, Han SH, Kim KS, Lee MS (December 2006). "Effects of aromatherapy massage on anxiety and self-esteem in korean elderly women: a pilot study". The International Journal of Neuroscience 116 (12): 1447–55. doi:10.1080/00207450500514268. PMID 17145679. 16. ^ Barrett, Stephen. "Aromatherapy: Making Dollars out of Scents", Science & Pseudoscience Review in Mental Health. Scientific Review of Mental Health Practice (SRMHP). Retrieved on 2009-08-10. 17. ^ "Lemon oil vapor causes an anti-stress effect via modulating the 5-HT and DA activities in mice.". PubMed.gov. 2006-06-15. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16780969&query_hl=6&itool=pubmed_docsum. Retrieved 2007-04-26. 18. ^ Ohio State University Research, March 3, 2008 Study is published in the March 2008 issue of the journal Psychoneuroendocrinology 19. ^ Antimicrobial and antiplasmid activities of essential oils. 20. ^ http://www.cancer.gov/cancertopics/pdq/cam/aromatherapy/HealthProfessional/page3 cancer.gov - Aromatherapy and Essential Oils 21. ^ "Antibacterial and antifungal properties of essential oils". Curr Med Chem. 10 (10): 813–29. 2003 May.. doi:10.2174/0929867033457719. PMID 12678685. 22. ^ "Essential oils of aromatic plants with antibacterial, antifungal, antiviral, and cytotoxic properties--an overview.". Forsch Komplementmed. 2 (2): 79–90. 2009 Apr;16. Epub 3 April 2009.. doi:10.1159/000207196. PMID 19420953. 23. ^ http://pmj.sagepub.com/cgi/content/abstract/18/2/87 A randomized controlled trial of aromatherapy massage in a hospice setting 24. ^ Ballard CG, O'Brien JT, Reichelt K, Perry EK (July 2002). "Aromatherapy as a safe and effective treatment for the management of agitation in severe dementia: the results of a double-blind, placebo-controlled trial with Melissa". J Clin Psychiatry 63 (7): 553–8. PMID 12143909. 25. ^ Holmes C, Hopkins V, Hensford C, MacLaughlin V, Wilkinson D, Rosenvinge H. (April 2002). "Lavender oil as a treatment for agitated behaviour in severe dementia: a placebo controlled study". Int J Geriatr Psychiatry 17 (4): 305–8.. doi:10.1002/gps.593. PMID 11994882. 26. ^ "The long-term effect of a mouthrinse containing essential oils on dental plaque and gingivitis: a systematic review". Periodontol. 78 (7): 1218–28. 2007 July. doi:10.1902/jop.2007.060269. PMID 17608576 : 17608576. 27. ^ http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1312240 Hyperpigmented macules and streaks 28. ^ Edwards, J.; Bienvenu, F.E. (1999). "Investigations into the use of flame and the herbicide, paraquat, to control peppermint rust in north-east Victoria, Australia". Australasian Plant Pathology 28 (3): 212–224. doi:10.1071/AP99036. 29. ^ Adamovic, D.S. et al.. "Variability of herbicide efficiency and their effect upon yield and quality of peppermint (Mentha X Piperital L.)". http://www.actahort.org/books/249/249_8.htm. Retrieved 6 June 2009. 30. ^ The Lavender Cat - Cats and Essential Oil Safety 31. ^ K. Bischoff, F. Guale (1998). "Australian tea tree (Melaleuca alternifolia) Oil Poisoning in three purebred cats" (–Scholar search). Journal of Veterinary Diagnostic Investigation 10 (108). Archived from the original on October 15, 2006. http://web.archive.org/web/20061015234207/http://www.vet-task-force.com/Abstract-tea-tree-oil.htm. Retrieved 2006-10-17. [dead link] 32. ^ Henley, D. V.; Lipson, N; Korach, KS; Bloch, CA (2007). "Prepubertal gynecomastia linked to lavender and tea tree oils". New England Journal of Medicine 356 (5): 479–85. doi:10.1056/NEJMoa064725. PMID 17267908. http://content.nejm.org/cgi/content/abstract/356/5/479. 33. ^ "Oils make male breasts develop". BBC News Online (London). 1 February 2007. http://news.bbc.co.uk/2/hi/health/6318043.stm. Retrieved 2007-09-09. 34. ^ 'NEITHER LAVENDER OIL NOR TEA TREE OIL CAN BE LINKED TO BREAST GROWTH IN YOUNG BOYS' 35. ^ 'ATTIA refutes gynecomastia link', Article Date: 21 February 2007 36. ^ Eucalyptus oil (PIM 031) 37. ^ Millet Y, Jouglard J, Steinmetz MD, Tognetti P, Joanny P, Arditti J. (December 1981). "Toxicity of some essential plant oils. Clinical and experimental study". Clin Toxicol. 18 (12): 1485–98. doi:10.3109/15563658108990357. PMID 7333081. [edit] Further reading * Burke, L., & Chambers, P. (1995). The very essence: A guide to aromatherapy. Silver Link. OCLC 60274302 * Lis-Balchin, Maria (2006). Aromatherapy science: A guide for healthcare professionals. London: Pharmaceutical Press. ISBN 0-85369-578-4 * Schnaubelt, Kurt (1998). Advanced aromatherapy: The science of essential oil therapy. Rochester, VT: Healing Arts Press. ISBN 0-89281-743-7 * Schnaubelt, Kurt (1999). Medical aromatherapy: Healing with essential oils. Berkeley, CA: Frog. ISBN 1-883319-69-2 * Valnet, Jean; & Tisserand, Robert (1990). The practice of aromatherapy: A classic compendium of plant medicines & their healing properties. Rochester, VT: Healing Arts Press. ISBN 0-89281-398-9 * National Research Council (2003). Food Chemicals Codex. Washington D.C.: National Academy Press. ISBN 0309088666. * Wanjek, Christopher (2003). Bad medicine: Misconceptions and misuses revealed, from distance healing to vitamin O. New York: J. Wiley. ISBN 0-471-43499-X * Valnet, Jean; & Tisserand, Robert (1982). The practice of aromatherapy. Saffron Walden: Daniel. ISBN 0-85207-143-4 [edit] External links Wikimedia Commons has media related to: Aromatherapy Wikibooks has a book on the topic of Complete Guide to Essential Oils * The National Association for Holistic Aromatherapy * International Federation of Aromatherapy * What Does the Research Say About Essential Oils? * Antiviral and Antimicrobial Properties of Essential Oils * The Aromatherapy Global Online Research Archives Journals * International Journal of Aromatherapy * International Journal of Clinical Aromatherapy Criticism * Aromatherapy - does it work? Smell Research by Tim Jacob * Aromatherapy: Making Dollars out of Scents
  • diffuser Return to the top
  • A diffuser is the mechanical device that is designed to control the characteristics of a fluid at the entrance to a thermodynamic open system. Diffusers are used to slow the fluid's velocity and to enhance its mixing into the surrounding fluid. In contrast, a nozzle is often intended to increase the discharge velocity and to direct the flow in one particular direction. Frictional effects may sometimes be important, but usually they are neglected. However, the external work transfer is always assumed to be zero. It is also assumed that changes in thermal energy are significantly greater than changes in potential energy and therefore the latter can usually be neglected for the purpose of analysis. Contents [hide] * 1 HVAC * 2 See also * 3 References * 4 External links [edit] HVAC A round diffuser in an HVAC system Diffusers are very common in heating, ventilating, and air-conditioning systems.[1] Diffusers are used on both all-air and air-water HVAC systems, as part of room air distribution subsystems, and serve several purposes: * To deliver both conditioning and ventilating air * Evenly distribute the flow of air, in the desired directions * To enhance mixing of room air into the primary air being discharged * Often to cause the air jet(s) to attach to a ceiling or other surface, taking advantage of the Coandă effect * To create low-velocity air movement in the occupied portion of room * Accomplish the above while producing the minimum amount of noise When possible, dampers, extractors, and other flow control devices should not be placed near diffusers' inlets (necks); either not being used at all or being placed far upstream. They have been shown to dramatically increase noise production. For as-cataloged diffuser performance, a straight section of duct needs serve a diffuser. An elbow, or kinked flex duct, just before a diffuser often leads to poor air distribution and increased noise. Diffusers may be round, rectangular, textile or linear slot diffusers (LSDs), for example. This last type takes the form of one or several long, narrow slots (hence the name), often semi-concealed in a fixed or suspended ceiling. Occasionally, diffusers are used in reverse fashion, as air inlets or 'returns'. This is especially true for LSDs and 'perf' diffusers. But more commonly, grilles are used as return or exhaust air inlets
  • portable Return to the top
  • Portable From Wikipedia, the free encyclopedia Jump to: navigation, search Look up portable in Wiktionary, the free dictionary. Portable may refer to: * Portable building, a manufactured structure that is built off site and moved in upon completion of site and utility work * Portable classroom, a temporary building installed on the grounds of a school to provide additional classroom space where there is a shortage of capacity * Portable toilet, a modern, portable, self-contained outhouse manufactured of molded plastic In computing: * Portable object (computing), a distributed computing term for an object which can be accessed through a normal method call while possibly residing in memory on another computer * Software portability, software that can easily be ported to multiple platforms * Portable applications, applications that do not require any kind of installation onto a computer, and can store data in the program's directory In electronics: * Portable electronics * Portable communications device, a wearable or handheld device * Portable audio player, a personal electronic device that allows the user to listen to recorded or broadcast audio whilst being mobile * Portable computer, a computer that is designed to be moved from one place to another o Compaq Portable series (1982–?) o Apricot Portable (1984) o IBM Portable Personal Computer (1984) o Macintosh Portable (1989–1991) from Apple Computer * Handheld game console, a lightweight, portable electronic machine for playing video games In music: * Portable Life, a 1999 album by Danielle Brisebois * Portable Sounds a 2007 album by TobyMac.
  • medical Return to the top
  • * jugum * forfend * affable * egregious medical - 6 dictionary results Medical Dictionary Find Words, Definitions, Spellings & More for Free. Get ReferenceBoss! www.ReferenceBoss.com Medi Cal Health Insurance Find Low Cost Health Insurance. One Quick Form. Multiple Offers. www.InsuranceDesk.com Diseases What is Mesothelioma? Resources & Links For Mesothelioma! www.globalhealthassist.net med·i·cal    /ˈmɛdɪkəl/ Show Spelled[med-i-kuhl] Show IPA –adjective 1. of or pertaining to the science or practice of medicine: medical history; medical treatment. 2. curative; medicinal; therapeutic: medical properties. 3. pertaining to or requiring treatment by other than surgical means. 4. pertaining to or giving evidence of the state of one's health: a medical discharge from the army; a medical examination. –noun 5. something done or received in regard to the state of one's health, as a medical examination. Use medical in a Sentence See images of medical Search medical on the Web Origin: 1640–50; < ML medicālis, equiv. to L medic ( us ) medical (adj.), physician (n.) (deriv. of medērī to heal; see -ic) + -ālis -al1 —Related forms med·i·cal·ly, adverb an·ti·med·i·cal, adjective an·ti·med·i·cal·ly, adverb non·med·i·cal, adjective non·med·i·cal·ly, adverb pseu·do·med·i·cal, adjective pseu·do·med·i·cal·ly, adverb qua·si-med·i·cal, adjective qua·si-med·i·cal·ly, adverb un·med·i·cal, adjective un·med·i·cal·ly, adverb Dictionary.com Unabridged Based on the Random House Dictionary, © Random House, Inc. 2011. Cite This Source | Link To medical Explore the Visual Thesaurus » Related Words for : medical checkup, health check, medical checkup, medical exam, medical examination View more related words » Dictionary Medical Get More Info On Causes, Symptoms, Treatments & Doctors At Healthline® Healthline.com/Health-Info Medical Definition Find Definitions For Any Word.Get Your Free Dictionary.com Toolbar. Dictionary.com World English Dictionary medical (ˈmɛdɪk ə l) [Click for IPA pronunciation guide] — adj 1. of or relating to the science of medicine or to the treatment of patients by drugs, etc, as opposed to surgery 2. a less common word for medicinal — n 3. informal a medical examination [C17: from Medieval Latin medicālis, from Latin medicus physician, surgeon, from medērī to heal] 'medically — adv Collins English Dictionary - Complete & Unabridged 10th Edition 2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009 Cite This Source Word Origin & History medical 1646, from Fr. médical, from L.L. medicalis "of a physician," from L. medicus "physician" (n.); "healing" (adj.), from mederi "to heal," originally "know the best course for," from PIE base *med- "to measure, limit, consider, advise" (cf. Gk. medos "counsel, plan, device, cunning," Avestan vi-mad "physician"); see meditation. Online Etymology Dictionary, © 2010 Douglas Harper Cite This Source Medical Dictionary 1 med·i·cal definition Pronunciation: /ˈmed-i-kəl/ Function: adj 1 : of, relating to, or concerned with physicians or the practice of medicine often as distinguished from surgery 2 : requiring or devoted to medical treatment medical emergency> med·i·cal·ly Pronunciation: /-k(ə-)lē/ Function: adv 2 medical definition Function: n : a medical examination Merriam-Webster's Medical Dictionary, © 2007 Merriam-Webster, Inc. Cite This Source medical med·i·cal (měd'ĭ-kəl) adj. 1. Of, relating to, or characterizing the study or practice of medicine. 2. Requiring treatment by medicine. n. A thorough physical examination. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. Cite This Source Famous Quotations medical "Determination and skill come out of a depth of politica..." "One fellow I was dating in medical school ... was a vet..." "Within Western medicine, physically ill people approach..." "In general a thing is romantic when, as Aristotle would..." "There may perhaps be a new generation of doctors horrif.
  • vacuum Return to the top
  • n everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure.[1] The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in practice. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they simply call "vacuum" or "free space", and use the term partial vacuum to refer to real vacuum. The Latin term in vacuo is also used to describe an object as being in what would otherwise be a vacuum. The quality of a vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%.[2] Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10−12) of atmospheric pressure, and can reach ≈100 particles/cm3.[3] Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average.[4] However, even if every single atom and particle could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, and other phenomena in quantum physics. Vacuum has been a frequent topic of philosophical debate since ancient Greek times, but was not studied empirically until the 17th century. Evangelista Torricelli produced the first laboratory vacuum in 1643, and other experimental techniques were developed as a result of his theories of atmospheric pressure. A torricellian vacuum is created by filling a tall glass container closed at one end with mercury and then inverting the container into a bowl to contain the mercury.[5] Vacuum became a valuable industrial tool in the 20th century with the introduction of incandescent light bulbs and vacuum tubes, and a wide array of vacuum technology has since become available. The recent development of human spaceflight has raised interest in the impact of vacuum on human health, and on life forms in general. A large vacuum chamber Contents [hide] * 1 Etymology * 2 Uses o 2.1 Vacuum driven machines * 3 Outer space * 4 Effects on humans and animals * 5 Historical interpretation * 6 In electromagnetism * 7 In quantum mechanics * 8 Pumping and ambient air pressure * 9 Outgassing * 10 Quality o 10.1 Examples * 11 Measurement o 11.1 Relative versus absolute measurement o 11.2 Vacuum measurements relative to 1 ATM * 12 See also * 13 Notes * 14 External links [edit] Etymology From Latin vacuum (an empty space, void) noun use of neuter of vacuus (empty) related to vacare (be empty). "Vacuum" is one of the few words in the English language that contains two consecutive 'u's. [edit] Uses Light bulbs contain a partial vacuum, usually backfilled with argon, which protects the tungsten filament Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges. [edit] Vacuum driven machines Vacuums are commonly used to produce suction, which has an even wider variety of applications. The Newcomen steam engine used vacuum instead of pressure to drive a piston. In the 19th century, vacuum was used for traction on Isambard Kingdom Brunel's experimental atmospheric railway. Vacuum brakes were once widely used on trains in the UK but, except on heritage railways, they have been replaced by air brakes. Manifold vacuum can be used to drive accessories on automobiles. The best-known application is the vacuum servo, used to provide power assistance for the brakes. Obsolete applications include vacuum-driven windscreen wipers and fuel pumps. [edit] Outer space Main article: Outer space Outer space is not a perfect vacuum, but a tenuous plasma awash with charged particles, electromagnetic fields, and the occasional star. Outer space has very low density and pressure, and is the closest physical approximation of a perfect vacuum. It has effectively no friction, allowing stars, planets and moons to move freely along ideal gravitational trajectories. But no vacuum is truly perfect, not even in interstellar space, where there are still a few hydrogen atoms per cubic centimetre.[4] Stars, planets and moons keep their atmospheres by gravitational attraction, and as such, atmospheres have no clearly delineated boundary: the density of atmospheric gas simply decreases with distance from the object. The Earth's atmospheric pressure drops to about 1 Pa (10−3 Torr) at 100 km of altitude, the Kármán line which is a common definition of the boundary with outer space. Beyond this line, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the sun and the dynamic pressure of the solar wind, so the definition of pressure becomes difficult to interpret. The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather. Astrophysicists prefer to use number density to describe these environments, in units of particles per cubic centimetre. But although it meets the definition of outer space, the atmospheric density within the first few hundred kilometers above the Kármán line is still sufficient to produce significant drag on satellites. Most artificial satellites operate in this region called low earth orbit and must fire their engines every few days to maintain orbit.[citation needed] The drag here is low enough that it could theoretically be overcome by radiation pressure on solar sails, a proposed propulsion system for interplanetary travel. Planets are too massive for their trajectories to be affected by these forces, although their atmospheres are eroded by the solar winds. All of the observable universe is filled with large numbers of photons, the so-called cosmic background radiation, and quite likely a correspondingly large number of neutrinos. The current temperature of this radiation is about 3 K, or -270 degrees Celsius or -454 degrees Fahrenheit. [edit] Effects on humans and animals See also: Human adaptation to space This painting, An Experiment on a Bird in the Air Pump by Joseph Wright of Derby, 1768, depicts an experiment performed by Robert Boyle in 1660. Humans and animals exposed to vacuum will lose consciousness after a few seconds and die of hypoxia within minutes, but the symptoms are not nearly as graphic as commonly depicted in media and popular culture. The reduction in pressure lowers the temperature at which blood and other body fluids boil, but the elastic pressure of blood vessels ensures that this boiling point remains above the internal body temperature of 37°C.[6] Although the blood will not boil, the formation of gas bubbles in bodily fluids at reduced pressures, known as ebullism, is still a concern. The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture.[7] Swelling and ebullism can be restrained by containment in a flight suit. Shuttle astronauts wear a fitted elastic garment called the Crew Altitude Protection Suit (CAPS) which prevents ebullism at pressures as low as 2 kPa (15 Torr).[8] Rapid evaporative cooling of the skin will create frost, particularly in the mouth, but this is not a significant hazard. Animal experiments show that rapid and complete recovery is normal for exposures shorter than 90 seconds, while longer full-body exposures are fatal and resuscitation has never been successful.[9] There is only a limited amount of data available from human accidents, but it is consistent with animal data. Limbs may be exposed for much longer if breathing is not impaired.[10] Robert Boyle was the first to show in 1660 that vacuum is lethal to small animals. During 1942, in one of a series of experiments on human subjects for the Luftwaffe, the Nazi regime experimented on prisoners in Dachau concentration camp by exposing them to low pressure.[11] Cold or oxygen-rich atmospheres can sustain life at pressures much lower than atmospheric, as long as the density of oxygen is similar to that of standard sea-level atmosphere. The colder air temperatures found at altitudes of up to 3 km generally compensate for the lower pressures there.[10] Above this altitude, oxygen enrichment is necessary to prevent altitude sickness in humans that did not undergo prior acclimatization, and spacesuits are necessary to prevent ebullism above 19 km.[10] Most spacesuits use only 20 kPa (150 Torr) of pure oxygen, just enough to sustain full consciousness. This pressure is high enough to prevent ebullism, but simple evaporation of blood can still cause decompression sickness and gas embolisms if not managed. Rapid decompression can be much more dangerous than vacuum exposure itself. Even if the victim does not hold his breath, venting through the windpipe may be too slow to prevent the fatal rupture of the delicate alveoli of the lungs.[10] Eardrums and sinuses may be ruptured by rapid decompression, soft tissues may bruise and seep blood, and the stress of shock will accelerate oxygen consumption leading to hypoxia.[12] Injuries caused by rapid decompression are called barotrauma. A pressure drop as small as 13 kPa (100 Torr), which produces no symptoms if it is gradual, may be fatal if it occurs suddenly.[10] Some extremophile microrganisms, such as tardigrades, can survive vacuum for a period of days. [edit] Historical interpretation Historically, there has been much dispute over whether such a thing as a vacuum can exist. Ancient Greek philosophers did not like to admit the existence of a vacuum, asking themselves "how can 'nothing' be something?". Plato found the idea of a vacuum inconceivable. He believed that all physical things were instantiations of an abstract Platonic ideal, and he could not conceive of an "ideal" form of a vacuum. Similarly, Aristotle considered the creation of a vacuum impossible — nothing could not be something. Later Greek philosophers thought that a vacuum could exist outside the cosmos, but not within it. Hero of Alexandria was the first to challenge this belief in the first century AD, but his attempts to create an artificial vacuum failed.[13] In the Roman city of Pompeii, a dual-action suction pump was found, proving that the ancient Romans had access to this kind of technology. Used for raising water, this pump had two cylinders, alternately operated by a walking-beam pump. In the suction phase, a lower valve opened, permitting the entry of water into the cylinder, while an upper valve remained closed. When the piston went down, the lower valve closed and the upper one opened.[14] In the medieval Islamic world, the Muslim physicist and philosopher, Al-Farabi (Alpharabius, 872-950), conducted a small experiment concerning the existence of vacuum, in which he investigated handheld plungers in water.[15][unreliable source?] He concluded that air's volume can expand to fill available space, and he suggested that the concept of perfect vacuum was incoherent.[16] However, the Muslim physicist Ibn al-Haytham (Alhazen, 965-1039) and the Mu'tazili theologians disagreed with Aristotle and Al-Farabi, and they supported the existence of a void. Using geometry, Ibn al-Haytham mathematically demonstrated that place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body.[17] Abū Rayhān al-Bīrūnī also states that "there is no observable evidence that rules out the possibility of vacuum".[18] The suction pump was described in 1206 by the Muslim engineer and inventor, Al-Jazari.[citation needed] The suction pump later appeared in Europe from the 15th century.[19][20][21] Taqi al-Din's six-cylinder 'Monobloc' pump, invented in 1551, could also create a partial vacuum.[citation needed] Torricelli's mercury barometer produced one of the first sustained vacuums in a laboratory. In medieval Europe, the Catholic Church regarded the idea of a vacuum as against nature or even heretical.[citation needed] The absence of anything implied the absence of God, and harkened back to the void prior to the creation story in the Book of Genesis. Medieval thought experiments into the idea of a vacuum considered whether a vacuum was present, if only for an instant, between two flat plates when they were rapidly separated. There was much discussion of whether the air moved in quickly enough as the plates were separated, or, as Walter Burley postulated, whether a 'celestial agent' prevented the vacuum arising. The commonly held view that nature abhorred a vacuum was called horror vacui. This speculation was shut down by the 1277 Paris condemnations of Bishop Etienne Tempier, which required there to be no restrictions on the powers of God, which led to the conclusion that God could create a vacuum if he so wished.[22] René Descartes also argued against the existence of a vacuum, arguing along the following lines:“Space is identical with extension, but extension is connected with bodies; thus there is no space without bodies and hence no empty space (vacuum)”. In spite of this, opposition to the idea of a vacuum existing in nature continued into the Scientific Revolution, with scholars such as Paolo Casati taking an anti-vacuist position. Jean Buridan reported in the 14th century that teams of ten horses could not pull open bellows when the port was sealed, apparently because of horror vacui.[13] The Crookes tube, used to discover and study cathode rays, was an evolution of the Geissler tube. The belief in horror vacui was overthrown in the 17th century. Water pump designs had improved by then to the point that they produced measurable vacuums, but this was not immediately understood. What was known was that suction pumps could not pull water beyond a certain height: 18 Florentine yards according to a measurement taken around 1635. (The conversion to metres is uncertain, but it would be about 9 or 10 metres.) This limit was a concern to irrigation projects, mine drainage, and decorative water fountains planned by the Duke of Tuscany, so the Duke commissioned Galileo to investigate the problem. Galileo advertised the puzzle to other scientists, including Gasparo Berti who replicated it by building the first water barometer in Rome in 1639.[23] Berti's barometer produced a vacuum above the water column, but he could not explain it. The breakthrough was made by Evangelista Torricelli in 1643. Building upon Galileo's notes, he built the first mercury barometer and wrote a convincing argument that the space at the top was a vacuum. The height of the column was then limited to the maximum weight that atmospheric pressure could support. Some people believe that although Torricelli's experiment was crucial, it was Blaise Pascal's experiments that proved the top space really contained vacuum. In 1654, Otto von Guericke invented the first vacuum pump[24] and conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been(partially) evacuated. Robert Boyle improved Guericke's design and conducted experiments on the properties of vacuum. Robert Hooke also helped Boyle produce an air pump which helped to produce the vacuum. The study of vacuum then lapsed until 1850 when August Toepler invented the Toepler Pump. Then in 1855 Heinrich Geissler invented the mercury displacement pump and achieved a record vacuum of about 10 Pa (0.1 Torr). A number of electrical properties become observable at this vacuum level, and this renewed interest in vacuum. This, in turn, led to the development of the vacuum tube. Shortly after this Hermann Sprengel invented the Sprengel Pump in 1865. While outer space has been likened to a vacuum, early theories of the nature of light relied upon the existence of an invisible, aetherial medium which would convey waves of light. (Isaac Newton relied on this idea to explain refraction and radiated heat).[25] This evolved into the luminiferous aether of the 19th century, but the idea was known to have significant shortcomings - specifically, that if the Earth were moving through a material medium, the medium would have to be both extremely tenuous (because the Earth is not detectably slowed in its orbit), and extremely rigid (because vibrations propagate so rapidly). An 1891 article by William Crookes noted: "the [freeing of] occluded gases into the vacuum of space".[26] Even up until 1912, astronomer Henry Pickering commented: "While the interstellar absorbing medium may be simply the ether, [it] is characteristic of a gas, and free gaseous molecules are certainly there".[27] In 1887, the Michelson-Morley experiment, using an interferometer to attempt to detect the change in the speed of light caused by the Earth moving with respect to the aether, was a famous null result. Many misinterpreted the results, which neither proved nor disproved the existence of the aether, as showing that there really was no static, pervasive medium throughout space and through which the Earth moved as though through a wind.[28][29] As a simplification, one can assume there no aether, and no such entity is required for the propagation of light. Besides the various particles which comprise cosmic radiation, there is a cosmic background of photonic radiation (electromagnetic radiation), including the cosmic microwave background (CMB), the thermal remnant of the Big Bang at about 2.7 K. However, none of these findings affect the outcome of the Michelson-Morley experiment to any significant degree. Einstein argued that physical objects are not located in space, but rather have a spatial extent. Seen this way, the concept of empty space loses its meaning.[30] Rather, space is an abstraction, based on the relationships between local objects. Nevertheless, the general theory of relativity admits a pervasive gravitational field, which, in Einstein's words,[31] may be regarded as an "aether", with properties varying from one location to another. One must take care, though, to not ascribe to it material properties such as velocity and so on. In 1930, Paul Dirac proposed a model of vacuum as an infinite sea of particles possessing negative energy, called the Dirac sea. This theory helped refine the predictions of his earlier formulated Dirac equation, and successfully predicted the existence of the positron, discovered two years later in 1932. Despite this early success, the idea was soon abandoned in favour of the more elegant quantum field theory. The development of quantum mechanics has complicated the modern interpretation of vacuum by requiring indeterminacy. Niels Bohr and Werner Heisenberg's uncertainty principle and Copenhagen interpretation, formulated in 1927, predict a fundamental uncertainty in the instantaneous measurability of the position and momentum of any particle, and which, not unlike the gravitational field, questions the emptiness of space between particles. In the late 20th century, this principle was understood to also predict a fundamental uncertainty in the number of particles in a region of space, leading to predictions of virtual particles arising spontaneously out of the void. In other words, there is a lower bound on the vacuum, dictated by the lowest possible energy state of the quantized fields in any region of space. [edit] In electromagnetism In classical electromagnetism, free space or perfect vacuum is a standard reference medium for electromagnetic effects.[32][33] In the theory of classical electromagnetism, free space has the following properties: * Electromagnetic radiation travels without obstructions, at the speed of light. * The superposition principle is always exactly true.[34] For example, the electric potential generated by two charges is the simple addition of the potentials generated by each charge in isolation. The value of the electric field at any point around these two charges is found by calculating the vector sum of the two electric fields from each of the charges acting alone. * The permittivity and permeability are exactly ε0 and μ0 respectively (in SI units), or exactly 1 (in Gaussian units). * The characteristic impedance (η) equals the impedance of free space Z0 ≈ 376.73 Ω. [edit] In quantum mechanics For more details on this topic, see vacuum state. In quantum mechanics and quantum field theory, the vacuum is defined as the state (i.e. solution to the equations of the theory) with the lowest possible energy (the ground state of the Hilbert space). This is a state with no matter particles (hence the name), and also no photons, no gravitons, etc. As described above, this state is impossible to achieve experimentally. (Even if every matter particle could somehow be removed from a volume, it would be impossible to eliminate all the blackbody photons.) This hypothetical vacuum state often has interesting and complex properties. For example, it contains vacuum fluctuations (virtual particles that hop into and out of existence). It also, relatedly, has a finite energy, called vacuum energy. Vacuum fluctuations are an essential and ubiquitous part of quantum field theory. Some readily-apparent effects of vacuum fluctuations include the Casimir effect and Lamb shift.[22] There can be more than one possible vacuum state. The starting and ending of cosmological inflation is thought to have arisen from transitions between different vacuum states. For theories obtained by quantization of a classical theory, each stationary point of the energy in the configuration space gives rise to a single vacuum. String theory is believed to have a huge number of vacua - the so-called string theory landscape. [edit] Pumping and ambient air pressure This shallow water well pump reduces atmospheric air pressure inside the pump chamber. Atmospheric pressure extends down into the well, and forces water up the pipe into the pump to balance the reduced pressure. Above-ground pump chambers are only effctive to a depth of approximately 9 meters due to the water column weight balancing the atmospheric pressure. Deep wells have the pump chamber down in the well close to the water surface, or in the water. A "sucker rod" extends from the handle down the center of the pipe deep into the well to operate the plunger. The pump handle acts as a heavy counterweight against both the sucker rod weight and the weight of the water column standing on the upper plunger up to ground level. Main article: Vacuum pump Fluids cannot generally be pulled, so a vacuum cannot be created by suction. Suction can spread and dilute a vacuum by letting a higher pressure push fluids into it, but the vacuum has to be created first before suction can occur. The easiest way to create an artificial vacuum is to expand the volume of a container. For example, the diaphragm muscle expands the chest cavity, which causes the volume of the lungs to increase. This expansion reduces the pressure and creates a partial vacuum, which is soon filled by air pushed in by atmospheric pressure. To continue evacuating a chamber indefinitely without requiring infinite growth, a compartment of the vacuum can be repeatedly closed off, exhausted, and expanded again. This is the principle behind positive displacement pumps, like the manual water pump for example. Inside the pump, a mechanism expands a small sealed cavity to create a vacuum. Because of the pressure differential, some fluid from the chamber (or the well, in our example) is pushed into the pump's small cavity. The pump's cavity is then sealed from the chamber, opened to the atmosphere, and squeezed back to a minute size. A cutaway view of a turbomolecular pump, a momentum transfer pump used to achieve high vacuum The above explanation is merely a simple introduction to vacuum pumping, and is not representative of the entire range of pumps in use. Many variations of the positive displacement pump have been developed, and many other pump designs rely on fundamentally different principles. Momentum transfer pumps, which bear some similarities to dynamic pumps used at higher pressures, can achieve much higher quality vacuums than positive displacement pumps. Entrapment pumps can capture gases in a solid or absorbed state, often with no moving parts, no seals and no vibration. None of these pumps are universal; each type has important performance limitations. They all share a difficulty in pumping low molecular weight gases, especially hydrogen, helium, and neon. The lowest pressure that can be attained in a system is also dependent on many things other than the nature of the pumps. Multiple pumps may be connected in series, called stages, to achieve higher vacuums. The choice of seals, chamber geometry, materials, and pump-down procedures will all have an impact. Collectively, these are called vacuum technique. And sometimes, the final pressure is not the only relevant characteristic. Pumping systems differ in oil contamination, vibration, preferential pumping of certain gases, pump-down speeds, intermittent duty cycle, reliability, or tolerance to high leakage rates. In ultra high vacuum systems, some very "odd" leakage paths and outgassing sources must be considered. The water absorption of aluminium and palladium becomes an unacceptable source of outgassing, and even the adsorptivity of hard metals such as stainless steel or titanium must be considered. Some oils and greases will boil off in extreme vacuums. The permeability of the metallic chamber walls may have to be considered, and the grain direction of the metallic flanges should be parallel to the flange face. The lowest pressures currently achievable in laboratory are about 10−13 torr (13 pPa).[35] However, pressures as low as 5×10−17 Torr (6.7 fPa) have been indirectly measured in a 4 K cryogenic vacuum system.[3] This corresponds to ≈100 particles/cm3. [edit] Outgassing Main article: Outgassing Evaporation and sublimation into a vacuum is called outgassing. All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. In man-made systems, outgassing has the same effect as a leak and can limit the achievable vacuum. Outgassing products may condense on nearby colder surfaces, which can be troublesome if they obscure optical instruments or react with other materials. This is of great concern to space missions, where an obscured telescope or solar cell can ruin an expensive mission. The most prevalent outgassing product in man-made vacuum systems is water absorbed by chamber materials. It can be reduced by desiccating or baking the chamber, and removing absorbent materials. Outgassed water can condense in the oil of rotary vane pumps and reduce their net speed drastically if gas ballasting is not used. High vacuum systems must be clean and free of organic matter to minimize outgassing. Ultra-high vacuum systems are usually baked, preferably under vacuum, to temporarily raise the vapour pressure of all outgassing materials and boil them off. Once the bulk of the outgassing materials are boiled off and evacuated, the system may be cooled to lower vapour pressures and minimize residual outgassing during actual operation. Some systems are cooled well below room temperature by liquid nitrogen to shut down residual outgassing and simultaneously cryopump the system. [edit] Quality The quality of a vacuum is indicated by the amount of matter remaining in the system, so that a high quality vacuum is one with very little matter left in it. Vacuum is primarily measured by its absolute pressure, but a complete characterization requires further parameters, such as temperature and chemical composition. One of the most important parameters is the mean free path (MFP) of residual gases, which indicates the average distance that molecules will travel between collisions with each other. As the gas density decreases, the MFP increases, and when the MFP is longer than the chamber, pump, spacecraft, or other objects present, the continuum assumptions of fluid mechanics do not apply. This vacuum state is called high vacuum, and the study of fluid flows in this regime is called particle gas dynamics. The MFP of air at atmospheric pressure is very short, 70 nm, but at 100 mPa (~1×10−3 Torr) the MFP of room temperature air is roughly 100 mm, which is on the order of everyday objects such as vacuum tubes. The Crookes radiometer turns when the MFP is larger than the size of the vanes. Vacuum quality is subdivided into ranges according to the technology required to achieve it or measure it. These ranges do not have universally agreed definitions, but a typical distribution is as follows:[36][37] pressure (Torr) pressure (Pa) Atmospheric pressure 760 101.3 kPa Low vacuum 760 to 25 100 kPa to 3 kPa Medium vacuum 25 to 1×10−3 3 kPa to 100 mPa High vacuum 1×10−3 to 1×10−9 100 mPa to 100 nPa Ultra high vacuum 1×10−9 to 1×10−12 100 nPa to 100 pPa Extremely high vacuum <1×10−12 <100 pPa Outer Space 1×10−6 to <3×10−17 100 µPa to <3fPa Perfect vacuum 0 0 Pa * Atmospheric pressure is variable but standardized at 101.325 kPa (760 Torr) * Low vacuum, also called rough vacuum or coarse vacuum, is vacuum that can be achieved or measured with rudimentary equipment such as a vacuum cleaner and a liquid column manometer. * Medium vacuum is vacuum that can be achieved with a single pump, but the pressure is too low to measure with a liquid or mechanical manometer. It can be measured with a McLeod gauge, thermal gauge or a capacitive gauge. * High vacuum is vacuum where the MFP of residual gases is longer than the size of the chamber or of the object under test. High vacuum usually requires multi-stage pumping and ion gauge measurement. Some texts differentiate between high vacuum and very high vacuum. * Ultra high vacuum requires baking the chamber to remove trace gases, and other special procedures. British and German standards define ultra high vacuum as pressures below 10−6 Pa (10−8 Torr).[38][39] * Deep space is generally much more empty than any artificial vacuum. It may or may not meet the definition of high vacuum above, depending on what region of space and astronomical bodies are being considered. For example, the MFP of interplanetary space is smaller than the size of the solar system, but larger than small planets and moons. As a result, solar winds exhibit continuum flow on the scale of the solar system, but must be considered as a bombardment of particles with respect to the Earth and Moon. * Perfect vacuum is an ideal state of no particles at all. It cannot be achieved in a laboratory, although there may be small volumes which, for a brief moment, happen to have no particles of matter in them. Even if all particles of matter were removed, there would still be photons and gravitons, as well as dark energy, virtual particles, and other aspects of the quantum vacuum. * Hard vacuum and Soft vacuum are terms that are defined with a dividing line defined differently by different sources, such as 5 psia,[40] one Torr,[41] or 0.1 Torr[42] the common denominator being that a hard vacuum is a higher vacuum than a soft one.
  • vaporizer Return to the top
  • An anaesthetic vaporiser is a device generally attached to an anaesthetic machine which delivers a given concentration of a volatile anaesthetic agent. Anaesthetic machine, showing sevoflurane (yellow) and isoflurane (purple) vaporisers on the right The design of these devices takes account of varying * ambient temperature * fresh gas flow * agent vapour pressure Contents [hide] * 1 Historical vaporisers * 2 Modern vaporisers * 3 Plenum vaporisers * 4 Drawover vaporisers * 5 Dual-circuit gas-vapour blender * 6 References * 7 External links [edit] Historical vaporisers Historically, ether (the first volatile agent) was first used by John Snow's inhaler (1847) but was superseded by the use of chloroform (1848). Ether then slowly made a revival (1862–1872) with regular use via Curt Schimmelbusch's "mask", a narcosis mask for dripping liquid ether. Now obsolete, it was a mask constructed of wire, and covered with cloth. Pressure and demand from dental surgeons for a more reliable method of administrating ether helped modernise its delivery. In 1877, Clover invented an ether inhaler with a water jacket, and by the late 1899 alternatives to ether came to the fore, mainly due to the introduction of spinal anaesthesia. Subsequently this resulted in the decline of ether (1930–1956) use due to the introduction of cyclopropane, trichloroethylene, and halothane. By the 1980s, the anaesthetic vaporiser had evolved considerably; subsequent modifications lead to a raft of additional safety features such as temperature compensation, a bimetallic strip, temperature-adjusted splitting ratio and anti-spill measures.... [edit] Modern vaporisers There are generally two types of vaporisers: plenum and drawover. Both have distinct advantages and disadvantages. A third type of vaporiser is exclusively used for the agent desflurane. [edit] Plenum vaporisers The plenum vaporiser is driven by positive pressure from the anaesthetic machine, and is usually mounted on the machine. The performance of the vaporiser does not change regardless of whether the patient is breathing spontaneously or is mechanically ventilated. The internal resistance of the vaporiser is usually high, but because the supply pressure is constant the vaporiser can be accurately calibrated to deliver a precise concentration of volatile anaesthetic vapour over a wide range of fresh gas flows. The plenum vaporiser is an elegant device which works reliably, without external power, for many hundreds of hours of continuous use, and requires very little maintenance. The plenum vaporiser works by accurately splitting the incoming gas into two streams. One of these streams passes straight through the vaporiser in the bypass channel. The other is diverted into the vaporising chamber. Gas in the vaporising chamber becomes fully saturated with volatile anaesthetic vapour. This gas is then mixed with the gas in the bypass channel before leaving the vaporiser. A typical volatile agent, isoflurane, has a saturated vapour pressure of 32kPa (about 1/3 of an atmosphere). This means that the gas mixture leaving the vaporising chamber has a partial pressure of isoflurane of 32kPa. At sea-level (atmospheric pressure is about 101kPa), this equates conveniently to a concentration of 32%. However, the output of the vaporiser is typically set at 1-2%, which means that only a very small proportion of the fresh gas needs to be diverted through the vaporising chamber (this proportion is known as the splitting ratio). It can also be seen that a plenum vaporiser can only work one way round: if it is connected in reverse, much larger volumes of gas enter the vaporising chamber, and therefore potentially toxic or lethal concentrations of vapour may be delivered. (Technically, although the dial of the vaporiser is calibrated in volume percent (e.g. 2%), what it actually delivers is a partial pressure of anaesthetic agent (e.g. 2kPa)). The performance of the plenum vaporiser depends extensively on the saturated vapour pressure of the volatile agent. This is unique to each agent, so it follows that each agent must only be used in its own specific vaporiser. Several safety systems, such as the Fraser-Sweatman system, have been devised so that filling a plenum vaporiser with the wrong agent is extremely difficult. A mixture of two agents in a vaporiser could result in unpredictable performance from the vaporiser. Saturated vapour pressure for any one agent varies with temperature, and plenum vaporisers are designed to operate within a specific temperature range. They have several features designed to compensate for temperature changes (especially cooling by evaporation). They often have a metal jacket weighing about 5 kg, which equilibrates with the temperature in the room and provides a source of heat. In addition, the entrance to the vaporising chamber is controlled by a bimetallic strip, which admits more gas to the chamber as it cools, to compensate for the loss of efficiency of evaporation. The first temperature-compensated plenum vaporiser was the Cyprane 'FluoTEC' Halothane vaporiser, released onto the market shortly after Halothane was introduced into clinical practice in 1956. [edit] Drawover vaporisers The drawover vaporiser is driven by negative pressure developed by the patient, and must therefore have a low resistance to gas flow. Its performance depends on the minute volume of the patient: its output drops with increasing minute ventilation. The design of the drawover vaporiser is much simpler: in general it is a simple glass reservoir mounted in the breathing attachment. Drawover vaporisers may be used with any liquid volatile agent (including older agents such as diethyl ether or chloroform, although it would be dangerous to use desflurane). Because the performance of the vaporiser is so variable, accurate calibration is impossible. However, many designs have a lever which adjusts the amount of fresh gas which enters the vaporising chamber. The drawover vaporiser may be mounted either way round, and may be used in circuits where re-breathing takes place, or inside the circle breathing attachment. Drawover vaporisers typically have no temperature compensating features. With prolonged use, the liquid agent may cool to the point where condensation and even frost may form on the outside of the reservoir. This cooling impairs the efficiency of the vaporiser. One way of minimising this effect is to place the vaporiser in a bowl of water. The relative inefficiency of the drawover vaporiser contributes to its safety. A more efficient design would produce too much anaesthetic vapour. The output concentration from a drawover vaporiser may greatly exceed that produced by a plenum vaporiser, especially at low flows. For safest use, the concentration of anaesthetic vapour in the breathing attachment should be continuously monitored. Despite its drawbacks, the drawover vaporiser is cheap to manufacture and easy to use. In addition, its portable design means that it can be used in the field or in veterinary anaesthesia. [edit] Dual-circuit gas-vapour blender The third category of vaporiser (a dual-circuit gas-vapour blender) was created specifically for the agent desflurane. Desflurane boils at 23.5C, which is very close to room temperature. This means that at normal operating temperatures, the saturated vapour pressure of desflurane changes greatly with only small fluctuations in temperature. This means that the features of a normal plenum vaporiser are not sufficient to ensure an accurate concentration of desflurane. Additionally, on a very warm day, all the desflurane would boil, and very high (potentially lethal) concentrations of desflurane might reach the patient. A desflurane vaporiser (e.g. the TEC 6 produced by Datex-Ohmeda) is heated to 39C and pressurised to 200kPa (and therefore requires electrical power). It is mounted on the anaesthetic machine in the same way as a plenum vaporiser, but its function is quite different. It evaporates a chamber containing desflurane using heat, and injects small amounts of pure desflurane vapour into the fresh gas flow. A transducer senses the fresh gas flow. A warm-up period is required after switching on. The desflurane vaporiser will fail if mains power is lost. Alarms sound if the vaporiser is nearly empty. An electronic display indicates the level of desflurane in the vaporiser. The expense and complexity of the desflurane vaporiser have contributed to the relative lack of popularity of desflurane, although in recent years it is gaining in popularity
  • collagen Return to the top
  • Collagen is a group of naturally occurring proteins. In nature, it is found exclusively in animals, especially in the flesh and connective tissues of mammals.[1] It is the main component of connective tissue, and is the most abundant protein in mammals,[2] making up about 25% to 35% of the whole-body protein content. Collagen, in the form of elongated fibrils, is mostly found in fibrous tissues such as tendon, ligament and skin, and is also abundant in cornea, cartilage, bone, blood vessels, the gut, and intervertebral disc. In muscle tissue it serves as a major component of endomysium. Collagen constitutes 1% to 2% of muscle tissue, and accounts for 6% of the weight of strong, tendinous muscles.[3] Gelatin, which is used in food and industry, is collagen that has been irreversibly hydrolyzed. Contents [hide] * 1 History and background * 2 Molecular structure * 3 Fibrillar structure * 4 Types and associated disorders * 5 Staining * 6 Synthesis o 6.1 Amino acids o 6.2 Collagen I formation o 6.3 Synthetic pathogenesis * 7 Use o 7.1 Industrial uses * 8 Medical uses o 8.1 Cardiac applications o 8.2 Cosmetic Surgery o 8.3 Reconstructive surgical uses * 9 Fossil record * 10 Art * 11 See also * 12 References * 13 External links [edit] History and background The molecular and packing structures of collagen have eluded scientists over decades of research. The first evidence that it possesses a regular structure at the molecular level was presented in the mid-1930s.[4][5] Since that time many prominent scholars, including Nobel laureates Crick, Pauling, Rich and Yonath and others including Brodsky, Berman, and Ramachandran, concentrated on the conformation of the collagen monomer. Several competing models, although correctly dealing with the conformation of each individual peptide chain, gave way to the triple-helical "Madras" model which provided an essentially correct model of the molecule's quaternary structure[6][7][8] although this model still required some refinement.[9][10][11][12] The packing structure of collagen has not been defined to the same degree outside of the fibrillar collagen types, although it has been long known to be hexagonal ...or quasi-hexagonal.[13][14][15] As with its monomeric structure, several conflicting models alleged that either the packing arrangement of collagen molecules is 'sheet-like' or microfibrillar.[16][17] The microfibrillar structure of collagen fibrils in tendon, cornea and cartilage has been directly imaged by electron microscopy.[18][19][20] In 2006, it was confirmed that the microfibrillar structure of adult tendon as described by Fraser, Miller, Wess (amongst others) was closest to the observed structure, although it over-simplified the topological progression of neighboring collagen molecules and hence did not predict the correct conformation of the discontinuous D-periodic pentameric arrangement termed simply: the microfibril.[21] [edit] Molecular structure The tropocollagen or "collagen molecule" is a subunit of larger collagen aggregates such as fibrils. It is approximately 300 nm long and 1.5 nm in diameter, made up of three polypeptide strands (called alpha chains), each possessing the conformation of a left-handed helix (its name is not to be confused with the commonly occurring alpha helix, a right-handed structure). These three left-handed helices are twisted together into a right-handed coiled coil, a triple helix or "super helix", a cooperative quaternary structure stabilized by numerous hydrogen bonds. With type I collagen and possibly all fibrillar collagens if not all collagens, each triple-helix associates into a right-handed super-super-coil that is referred to as the collagen microfibril. Each microfibril is interdigitated with its neighboring microfibrils to a degree that might suggest that they are individually unstable although within collagen fibrils they are so well ordered as to be crystalline. A distinctive feature of collagen is the regular arrangement of amino acids in each of the three chains of these collagen subunits. The sequence often follows the pattern Gly-Pro-X or Gly-X-Hyp, where X may be any of various other amino acid residues. Proline or hydroxyproline constitute about 1/6 of the total sequence. With glycine accounting for the 1/3 of the sequence, this means that approximately half of the collagen sequence is not glycine, proline or hydroxyproline, a fact often missed due to the distraction of the unusual GX1X2 character of collagen alpha-peptides. This kind of regular repetition and high glycine content is found in only a few other fibrous proteins, such as silk fibroin. About 75-80% of silk is (approximately) -Gly-Ala-Gly-Ala- with 10% serine, and elastin is rich in glycine, proline, and alanine (Ala), whose side group is a small, inert methyl group. Such high glycine and regular repetitions are never found in globular proteins save for very short sections of their sequence. Chemically-reactive side groups are not needed in structural proteins as they are in enzymes and transport proteins, however collagen is not quite just a structural protein. Due to its key role in the determination of cell phenotype, cell adhesion, tissue regulation and infrastructure, many sections of its non-proline rich regions have cell or matrix association / regulation roles. The relatively high content of proline and hydroxyproline rings, with their geometrically constrained carboxyl and (secondary) amino groups, along with the rich abundance of glycine, accounts for the tendency of the individual polypeptide strands to form left-handed helices spontaneously, without any intrachain hydrogen bonding. Because glycine is the smallest amino acid with no side chain, it plays a unique role in fibrous structural proteins. In collagen, Gly is required at every third position because the assembly of the triple helix puts this residue at the interior (axis) of the helix, where there is no space for a larger side group than glycine’s single hydrogen atom. For the same reason, the rings of the Pro and Hyp must point outward. These two amino acids help stabilize the triple helix—Hyp even more so than Pro; a lower concentration of them is required in animals such as fish, whose body temperatures are lower than most warm-blooded animals. [edit] Fibrillar structure The tropocollagen subunits spontaneously self-assemble, with regularly staggered ends, into even larger arrays in the extracellular spaces of tissues.[22][23] In the fibrillar collagens, the molecules are staggered from each other by about 67 nm (a unit that is referred to as ‘D’ and changes depending upon the hydration state of the aggregate). Each D-period contains 4 and a fraction collagen molecules. This is because 300 nm divided by 67 nm does not give an integer (the length of the collagen molecule divided by the stagger distance D). Therefore in each D-period repeat of the microfibril, there is a part containing five molecules in cross-section—called the “overlap” and a part containing only 4 molecules, called the "gap".[21] The triple-helices are also arranged in a hexagonal or quasi-hexagonal array in cross-section, in both the gap and overlap regions.[21][13] There is some covalent crosslinking within the triple helices, and a variable amount of covalent crosslinking between tropocollagen helices forming well organized aggregates (such as fibrils).[24] Larger fibrillar bundles are formed with the aid of several different classes of proteins (including different collagen types), glycoproteins and proteoglycans to form the different types of mature tissues from alternate combinations of the same key players.[23] Collagen's insolubility was a barrier to the study of monomeric collagen until it was found that tropocollagen from young animals can be extracted because it is not yet fully crosslinked. However, advances in microscopy techniques electron microscopy (EM) and atomic force microscopy (AFM)) and X-ray diffraction have enabled researchers to obtain increasingly detailed images of collagen structure in situ. These later advances are particularly important to better understanding the way in which collagen structure affects cell-cell and cell-matrix communication, and how tissues are constructed in growth and repair, and changed in development and disease.[25][26] Collagen fibrils are semicrystalline aggregates of collagen molecules. Collagen fibers are bundles of fibrils. Collagen fibrils/aggregates are arranged in different combinations and concentrations in various tissues to provide varying tissue properties. In bone, entire collagen triple helices lie in a parallel, staggered array. Forty nm gaps between the ends of the tropocollagen subunits (approximately equal to the gap region) probably serve as nucleation sites for the deposition of long, hard, fine crystals of the mineral component, which is (approximately) hydroxyapatite, Ca10(PO4)6(OH)2 with some phosphate. It is in this way that certain kinds of cartilage turn into bone. Type I collagen gives bone its tensile strength. [edit] Types and associated disorders Collagen occurs in many places throughout the body. So far, only 29 types of collagen have been identified and described. Over 90% of the collagen in the body, however, is of type I[27] * Collagen One: skin, tendon, vascular, ligature, organs, bone (main component of bone) * Collagen Two: cartilage (main component of cartilage) * Collagen Three: reticulate (main component of reticular fibers), commonly found alongside type I. * Collagen Four: forms bases of cell basement membrane * Collagen Five: cells surfaces, hair and placenta Collagen-related diseases most commonly arise from genetic defects or nutritional deficiencies that affect the biosynthesis, assembly, postranslational modification, secretion, or other processes involved in normal collagen production. Type Notes Gene(s) Disorders I This is the most abundant collagen of the human body. It is present in scar tissue, the end product when tissue heals by repair. It is found in tendons, skin, artery walls, the endomysium of myofibrils, fibrocartilage, and the organic part of bones and teeth. COL1A1, COL1A2 osteogenesis imperfecta, Ehlers-Danlos Syndrome, Infantile cortical hyperostosis aka Caffey's disease II Hyaline cartilage, makes up 50% of all cartilage protein. Vitreous humour of the eye. COL2A1 Collagenopathy, types II and XI III This is the collagen of granulation tissue, and is produced quickly by young fibroblasts before the tougher type I collagen is synthesized. Reticular fiber. Also found in artery walls, skin, intestines and the uterus COL3A1 Ehlers-Danlos Syndrome IV basal lamina; eye lens. Also serves as part of the filtration system in capillaries and the glomeruli of nephron in the kidney. COL4A1, COL4A2, COL4A3, COL4A4, COL4A5, COL4A6 Alport syndrome, Goodpasture's syndrome V most interstitial tissue, assoc. with type I, associated with placenta COL5A1, COL5A2, COL5A3 Ehlers-Danlos syndrome (Classical) VI most interstitial tissue, assoc. with type I COL6A1, COL6A2, COL6A3 Ulrich myopathy and Bethlem myopathy VII forms anchoring fibrils in dermal epidermal junctions COL7A1 epidermolysis bullosa dystrophica VIII some endothelial cells COL8A1, COL8A2 Posterior polymorphous corneal dystrophy 2 IX FACIT collagen, cartilage, assoc. with type II and XI fibrils COL9A1, COL9A2, COL9A3 - EDM2 and EDM3 X hypertrophic and mineralizing cartilage COL10A1 Schmid metaphyseal dysplasia XI cartilage COL11A1, COL11A2 Collagenopathy, types II and XI XII FACIT collagen, interacts with type I containing fibrils, decorin and glycosaminoglycans COL12A1 - XIII transmembrane collagen, interacts with integrin a1b1, fibronectin and components of basement membranes like nidogen and perlecan. COL13A1 - XIV FACIT collagen COL14A1 - XV - COL15A1 - XVI - COL16A1 - XVII transmembrane collagen, also known as BP180, a 180 kDa protein COL17A1 Bullous pemphigoid and certain forms of junctional epidermolysis bullosa XVIII source of endostatin COL18A1 - XIX FACIT collagen COL19A1 - XX - COL20A1 - XXI FACIT collagen COL21A1 - XXII - COL22A1 - XXIII MACIT collagen - COL23A1 - XXIV - COL24A1 - XXV - COL25A1 - XXVI - EMID2 - XXVII - COL27A1 - XXVIII - COL28A1 - XXIX epidermal collagen COL29A1 Atopic dermatitis[28] In addition to the above mentioned disorders, excessive deposition of collagen occurs in scleroderma. [edit] Staining This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2010) In histology, collagen is brightly eosinophilic (pink) in standard H&E slides. The dye methyl violet may be used to stain the collagen in tissue samples. The dye methyl blue can also be used to stain collagen and immunohistochemical stains are available if required. The best stain for use in differentiating collagen from other fibers is Masson's trichrome stain. [edit] Synthesis Action of lysyl oxidase [edit] Amino acids Collagen has an unusual amino acid composition and sequence: * Glycine (Gly) is found at almost every third residue * Proline (Pro) makes up about 17% of collagen * Collagen contains two uncommon derivative amino acids not directly inserted during translation. These amino acids are found at specific locations relative to glycine and are modified post-translationally by different enzymes, both of which require vitamin C as a cofactor. o Hydroxyproline (Hyp), derived from proline. o Hydroxylysine (Hyl), derived from lysine (Lys). Depending on the type of collagen, varying numbers of hydroxylysines are glycosylated (mostly having disaccharides attached). Cortisol stimulates degradation of (skin) collagen into amino acids.[29] [edit] Collagen I formation Most collagen forms in a similar manner, but the following process is typical for type I: 1. Inside the cell 1. Two types of peptide chains are formed during translation on ribosomes along the rough endoplasmic reticulum (RER): alpha-1 and alpha-2 chains. These peptide chains (known as preprocollagen) have registration peptides on each end and a signal peptide. 2. Polypeptide chains are released into the lumen of the RER. 3. Signal peptides are cleaved inside the RER and the chains are now known as pro-alpha chains. 4. Hydroxylation of lysine and proline amino acids occurs inside the lumen. This process is dependent on ascorbic acid (Vitamin C) as a cofactor. 5. Glycosylation of specific hydroxylysine residues occurs. 6. Triple helical structure is formed inside the endoplasmic reticulum from each two alpha-1 chains and one alpha-2 chain. 7. Procollagen is shipped to the golgi apparatus, where it is packaged and secreted by exocytosis. 2. Outside the cell 1. Registration peptides are cleaved and tropocollagen is formed by procollagen peptidase. 2. Multiple tropocollagen molecules form collagen fibrils, via covalent cross-linking by lysyl oxidase which links hydroxylysine and lysine residues. Multiple collagen fibrils form into collagen fibers. 3. Collagen may be attached to cell membranes via several types of protein, including fibronectin and integrin. [edit] Synthetic pathogenesis Vitamin C deficiency causes scurvy, a serious and painful disease in which defective collagen prevents the formation of strong connective tissue. Gums deteriorate and bleed, with loss of teeth; skin discolors, and wounds do not heal. Prior to the eighteenth century, this condition was notorious among long duration military, particularly naval, expeditions during which participants were deprived of foods containing Vitamin C. An autoimmune disease such as lupus erythematosus or rheumatoid arthritis[30] may attack healthy collagen fibers. Many bacteria and viruses have virulence factors which destroy collagen or interfere with its production. [edit] Use Collagen is one of the long, fibrous structural proteins whose functions are quite different from those of globular proteins such as enzymes. Tough bundles of collagen called collagen fibers are a major component of the extracellular matrix that supports most tissues and gives cells structure from the outside, but collagen is also found inside certain cells. Collagen has great tensile strength, and is the main component of fascia, cartilage, ligaments, tendons, bone and skin.[31][32] Along with soft keratin, it is responsible for skin strength and elasticity, and its degradation leads to wrinkles that accompany ageing. It strengthens blood vessels and plays a role in tissue development. It is present in the cornea and lens of the eye in crystalline form. It is also used in cosmetic surgery and burns surgery. Hydrolyzed collagen can play an important role in weight management, as a protein, it can be advantageously used for its satiating power.[citation needed] [edit] Industrial uses If collagen is sufficiently denatured, e.g. by heating, the three tropocollagen strands separate partially or completely into globular domains, containing a different secondary structure to the normal collagen polyproline II (PPII), e.g. random coils. This process describes the formation of gelatin, which is used in many foods, including flavored gelatin desserts. Besides food, gelatin has been used in pharmaceutical, cosmetic, and photography industries.[33] From a nutritional point of view, collagen and gelatin are a poor-quality sole source of protein since they do not contain all the essential amino acids in the proportions that the human body requires—they are not 'complete proteins' (as defined by food science, not that they are partially structured). Manufacturers of collagen-based dietary supplements claim that their products can improve skin and fingernail quality as well as joint health. However, mainstream scientific research has not shown strong evidence to support these claims.[citation needed] Individuals with problems in these areas are more likely to be suffering from some other underlying condition (such as normal aging, dry skin, arthritis etc.) rather than just a protein deficiency. From the Greek for glue, kolla, the word collagen means "glue producer" and refers to the early process of boiling the skin and sinews of horses and other animals to obtain glue. Collagen adhesive was used by Egyptians about 4,000 years ago, and Native Americans used it in bows about 1,500 years ago. The oldest glue in the world, carbon-dated as more than 8,000 years old, was found to be collagen—used as a protective lining on rope baskets and embroidered fabrics, and to hold utensils together; also in crisscross decorations on human skulls.[34] Collagen normally converts to gelatin, but survived due to the dry conditions. Animal glues are thermoplastic, softening again upon reheating, and so they are still used in making musical instruments such as fine violins and guitars, which may have to be reopened for repairs—an application incompatible with tough, synthetic plastic adhesives, which are permanent. Animal sinews and skins, including leather, have been used to make useful articles for millennia. Gelatin-resorcinol-formaldehyde glue (and with formaldehyde replaced by less-toxic pentanedial and ethanedial) has been used to repair experimental incisions in rabbit lungs.[35] [edit] Medical uses [edit] Cardiac applications This section may require cleanup to meet Wikipedia's quality standards. Please improve this section if you can. The talk page may contain suggestions. (January 2011) [citation needed] The four dense collagen Valve rings, the Central Body of the Heart and the Cardiac Skeleton of the Heart are histologically bound to the Myocardium. Collagen contribution to Heart Performance summarily represents an essential, unique and moving solid anchor opposed to the Fluid mechanics of Blood within the heart. This structure is an impermeable firewall that excludes both blood and electrical influence (except through anatomical channels) from the upper to the lower chambers of the heart. As proof, one could posit that Atrial Fibrillation almost never deteriorates to Ventricular Fibrillation. Individual valvular leaflets are held in Sail shape by collagen under variable Pressure. Calcium deposition within collagen occurs as a natural consequence of aging. Calcium rich fixed points in an otherwise moving display of blood and muscle enable current Cardiac Imaging technology to arrive at ratios essentially stating blood in Cardiac Input and blood out Cardiac Output. Specified imaging such as Calcium Scoring illustrates the utility of this methodology, especially in an aging patient subject to pathology of the collagen underpinning. [edit] Cosmetic Surgery Collagen has been widely used in cosmetic surgery, as a healing aid for burn patients for reconstruction of bone and a wide variety of dental, orthopedic and surgical purposes. Some points of interest are: 1. when used cosmetically, there is a chance of allergic reactions causing prolonged redness; however, this can be virtually eliminated by simple and inconspicuous patch testing prior to cosmetic use, and 2. most medical collagen is derived from young beef cattle (bovine) from certified BSE (Bovine spongiform encephalopathy) free animals. Most manufacturers use donor animals from either "closed herds", or from countries which have never had a reported case of BSE such as Australia, Brazil and New Zealand. 3. porcine (pig) tissue is also widely used for producing collagen sheet for a variety of surgical purposes. 4. alternatives using the patient's own fat, hyaluronic acid or polyacrylamide gel are readily available. [edit] Reconstructive surgical uses Collagens are widely employed in the construction of artificial skin substitutes used in the management of severe burns. These collagens may be derived from bovine, equine or porcine, and even human, sources and are sometimes used in combination with silicones, glycosaminoglycans, fibroblasts, growth factors and other substances. Collagen is also sold as a pill commercially as a joint mobility supplement with poor references.[36] Because proteins are broken down into amino acids before absorption, there is no reason for orally ingested collagen to affect connective tissue in the body, except through the effect of individual amino acid supplementation. Recently an alternative to animal-derived collagen has become available. Although expensive, this human collagen, derived from donor cadavers, placentas and aborted fetuses, may minimize the possibility of immune reactions. Although it cannot be absorbed through the skin, collagen is now being used as a main ingredient for some cosmetic makeup.[37] Collagen is also frequently used in scientific research applications for cell culture, studying cell behavior and cellular interactions with the extracellular environment.[38] Suppliers such as Trevigen manufacture rat and bovine Collagen I and mouse Collagen IV.
  • acne Return to the top
  • Acne vulgaris (or acne) is a common human skin disease, characterized by areas of skin with seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), nodules (large papules) and possibly scarring.[1] Acne affects mostly skin with the densest population of sebaceous follicles; these areas include the face, the upper part of the chest, and the back. Severe acne is inflammatory, but acne can also manifest in noninflammatory forms.[2] The lesions are caused by changes in pilosebaceous units, skin structures consisting of a hair follicle and its associated sebaceous gland, changes that require androgen stimulation. Acne occurs most commonly during adolescence, and often continues into adulthood. In adolescence, acne is usually caused by an increase in male sex hormones, which people of both genders accrue during puberty.[3] For most people, acne diminishes over time and tends to disappear — or at the very least decrease — after one reaches one's early twenties. There is, however, no way to predict how long it will take to disappear entirely, and some individuals will carry this condition well into their thirties, forties, and beyond.[4] Some of the large nodules were previously called "cysts" and the term nodulocystic has been used to describe severe cases of inflammatory acne.[5] The "cysts," or boils that accompany cystic acne, can appear on the buttocks, groin, and armpit area, and anywhere else where sweat collects in hair follicles and perspiration ducts.[6] Cystic acne affects deeper skin tissue than does common acne.[7] Aside from scarring, its main effects are psychological, such as reduced self-esteem[8] and, according to at least one study, depression or suicide.[9] Acne usually appears during adolescence, when people already tend to be most socially insecure. Early and aggressive treatment is therefore advocated by some to lessen the overall impact to individuals.[8] Contents [hide] * 1 Terminology * 2 Signs and symptoms o 2.1 Scars o 2.2 Pigmentation * 3 Cause o 3.1 Hormonal o 3.2 Genetic o 3.3 Psychological o 3.4 Infectious o 3.5 Diet * 4 Diagnosis o 4.1 Differential * 5 Management o 5.1 Medications o 5.2 Procedures + 5.2.1 Dermabrasion + 5.2.2 Phototherapy # 5.2.2.1 'Blue' and red light # 5.2.2.2 Photodynamic therapy # 5.2.2.3 Laser treatment + 5.2.3 Surgery o 5.3 Other * 6 Prognosis * 7 Epidemiology * 8 History * 9 Research * 10 See also * 11 References [edit] Terminology The term acne comes from a corruption of the Greek ἀκμή (akmē), literally "point, edge", but in the sense of a "skin eruption"[10] in the writings of Aëtius Amidenus. Used by itself, the term "acne" refers to the presence of pustules and papules.[11] The most common form of acne is known as "acne vulgaris", meaning "common acne". Many teenagers get this type of acne. Use of the term "acne vulgaris" implies the presence of comedones.[12] The term "acne rosacea" is a synonym for rosacea, however some individuals may have almost no acne comedones associated with their rosacea and prefer therefore the term rosacea.[13] Chloracne is associated with exposure to polyhalogenated compounds. [edit] Signs and symptoms Typical features of acne include: seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), nodules (large papules) and, possibly scarring.[1] It presents somewhat differently in people with dark skin. [edit] Scars Acne scars are the result of inflammation within the dermis brought on by acne. The scar is created by the wound trying to heal itself resulting in too much collagen in one spot.[14] Physical acne scars are often referred to as "Icepick" scars. This is because the scars tend to cause an indentation in the skin's surface. There are a range of treatments available. Although quite rare, the medical condition Atrophia Maculosa Varioliformis Cutis also results in "acne-like" depressed scars on the face. * Ice pick scars: Deep pits, that are the most common and a classic sign of acne scarring. * Box car scars: Angular scars that usually occur on the temple and cheeks, and can be either superficial or deep, these are similar to chickenpox scars. * Rolling scars: Scars that give the skin a wave-like appearance. * Hypertrophic scars: Thickened, or keloid scars. [edit] Pigmentation Pigmented scars is a slightly misleading term, as it suggests a change in the skin's pigmentation and that they are true scars; however, neither is true. Pigmented scars are usually the result of nodular or cystic acne (the painful 'bumps' lying under the skin). They often leave behind an inflamed red mark. Often, the pigmentation scars can be avoided simply by avoiding aggravation of the nodule or cyst. Pigmentation scars nearly always fade with time taking between three months to two years to do so, although can last forever if untreated. A severe case of cystic acne Cystic acne on the back. Different types of Acne Vulgaris: A: Cystic acne on the face, B: Subsiding tropical acne of trunk, C: Extensive acne on chest and shoulders. [edit] Cause Acne develops as a result of blockages in follicles. Hyperkeratinization and formation of a plug of keratin and sebum (a microcomedo) is the earliest change. Enlargement of sebaceous glands and an increase in sebum production occur with increased androgen (DHEA-S) production at adrenarche. The microcomedo may enlarge to form an open comedone (blackhead) or closed comedone (milia). Comedones are the direct result of sebaceous glands' becoming clogged with sebum, a naturally occurring oil, and dead skin cells. In these conditions, the naturally occurring largely commensal bacterium Propionibacterium acnes can cause inflammation, leading to inflammatory lesions (papules, infected pustules, or nodules) in the dermis around the microcomedo or comedone, which results in redness and may result in scarring or hyperpigmentation.[15] [edit] Hormonal Hormonal activity, such as menstrual cycles and puberty, may contribute to the formation of acne. During puberty, an increase in male sex hormones called androgens cause the follicular glands to grow larger and make more sebum.[16] Use of anabolic steroids may have a similar effect.[17] Several hormones have been linked to acne: the androgens testosterone, dihydrotestosterone (DHT) and dehydroepiandrosterone sulfate (DHEAS), as well as insulin-like growth factor 1 (IGF-I). Development of acne vulgaris in later years is uncommon, although this is the age group for rosacea, which may have similar appearances. True acne vulgaris in adult women may be a feature of an underlying condition such as pregnancy and disorders such as polycystic ovary syndrome or the rare Cushing's syndrome. Menopause-associated acne occurs as production of the natural anti-acne ovarian hormone estradiol fails at menopause. The lack of estradiol also causes thinning hair, hot flashes, thin skin, wrinkles, vaginal dryness, and predisposes to osteopenia and osteoporosis as well as triggering acne (known as acne climacterica in this situation). [edit] Genetic The tendency to develop acne runs in families. For example, school aged boys with acne often have other members in their family with acne, as well. A family history of acne is associated with an earlier occurrence of acne and an increased number of retentional acne lesions.[18] [edit] Psychological While the connection between acne and stress has been debated, scientific research indicates that "increased acne severity" is "significantly associated with increased stress levels."[19] The National Institutes of Health (USA) list stress as a factor that "can cause an acne flare."[20] A study of adolescents in Singapore "observed a statistically significant positive correlation […] between stress levels and severity of acne."[21] It is also not clear whether acne causes stress and thus perpetuates itself to some extent. [edit] Infectious Bacteria in the pores. Propionibacterium acnes (P. acnes) is the anaerobic bacterium that causes acne. In vitro resistance of P. acnes to commonly used antibiotics has been increasing.[22] [edit] Diet A high glycemic load diet and cow's milk have been associated with worsening acne.[23] Other associations such as chocolate and salt are not supported by the evidence.[23] [edit] Diagnosis There are multiple grading scales for grading the severity of acne vulgaris,[24] three of these being: * Leeds acne grading technique: Counts and categorises lesions into inflammatory and non-inflammatory (ranges from 0-10.0). * Cook's acne grading scale: Uses photographs to grade severity from 0 to 8 (0 being the least severe and 8 being the most severe). * Pillsbury scale: Simply classifies the severity of the acne from 1 (least severe) to 4 (most severe). [edit] Differential * Keratosis pilaris * Rosacea * Chloracne [edit] Management Benzoyl peroxide cream. Many different treatments exist for acne including benzoyl peroxide, antibiotics, retinoids, antiseborrheic medications, salicylic acid, alpha hydroxy acid, azelaic acid, nicotinamide, and kera-tolytic soaps.[25] They are believed to work in at least 4 different ways including: normalising shedding into the pore to prevent blockage, killing Propionibacterium acnes, anti-inflammatory effects, hormonal manipulation.[citation needed] [edit] Medications Benzoyl peroxide Benzoyl peroxide is a first-line treatment for mild and moderate acne vulgaris due to its effectiveness and mild side-effects (primarily an irritant dermatitis). It normally causes just dryness of the skin, slight redness, and occasional peeling as part of some side-effects.[26] This topical does increase sensitivity to the sun as indicated on the package, so sunscreen should be used during the treatment to prevent sunburn. Benzoyl peroxide has been found to be nearly as effective as antibiotics with all concentrations 2.5%, 5.0%, and 10% equally effective.[26] Unlike antibiotics, benzoyl peroxide does not appear to generate bacterial resistance.[26] Antibiotics Antibiotics are reserved for more severe cases.[26] With increasing resistance of P. acnes worldwide, they are becoming less effective.[26] Commonly used antibiotics, either applied topically or taken orally, include erythromycin, clindamycin, and tetracyclines such as minocycline. Hormones In females, acne can be improved with hormonal treatments. The common combined estrogen/progestogen methods of hormonal contraception have some effect, but the antiandrogen cyproterone in combination with an oestrogen (Diane 35) is particularly effective at reducing androgenic hormone levels. Diane-35 is not available in the USA, but a newer oral contraceptive containing the progestin drospirenone is now available with fewer side-effects than Diane 35 / Dianette. Both can be used where blood tests show abnormally high levels of androgens, but are effective even when this is not the case. Along with this, treatment with low-dose spironolactone can have anti-androgenetic properties, especially in patients with polycystic ovarian syndrome. Topical retinoids A group of medications for normalizing the follicle cell life-cycle are topical retinoids such as tretinoin (Retin-A), adapalene (Differin), and tazarotene (Tazorac). Like isotretinoin, they are related to vitamin A, but they are administered as topicals and, in general, have much milder side-effects. They can, however, cause significant irritation of the skin. The retinoids appear to influence the cell creation and death life-cycle of cells in the follicle lining. This helps prevent the hyperkeratinization of these cells that can create a blockage. Retinol, a form of vitamin A, has similar, but milder, effects and is used in many over-the-counter moisturizers and other topical products. Effective topical retinoids have been in use for over 30 years, but are available only on prescription, so are not as widely used as the other topical treatments. Topical retinoids often cause an initial flare-up of acne and facial flushing. Oral retinoids A daily oral intake of vitamin A derivative isotretinoin (marketed as Roaccutane, Accutane, Amnesteem, Sotret, Claravis, Clarus) over a period of 4–6 months can cause long-term resolution or reduction of acne. It is believed that isotretinoin works primarily by reducing the secretion of oils from the glands, however some studies suggest that it affects other acne-related factors as well. Isotretinoin has been shown to be very effective in treating severe acne and can either improve or clear well over 80% of patients. The drug has a much longer effect than anti-bacterial treatments and will often cure acne for good. The treatment requires close medical supervision by a dermatologist because the drug has many known side-effects (many of which can be severe). About 25% of patients may relapse after one treatment. In those cases, a second treatment for another 4–6 months may be indicated to obtain desired results. It is often recommended that one let a few months pass between the two treatments, because the condition can actually improve somewhat in the time after stopping the treatment and waiting a few months also gives the body a chance to recover. On occasion, a third or even a fourth course is used, but the benefits are often less substantial. The most common side-effects are dry skin and occasional nosebleeds (secondary to dry nasal mucosa). Oral retinoids also often cause an initial flare-up of acne within a month or so, which can be severe. There are reports that the drug has damaged the liver of patients. For this reason, it is recommended that patients have blood samples taken and examined before and during treatment. In some cases, treatment is terminated or reduced due to elevated liver enzymes in the blood, which might be related to liver damage. Others claim that the reports of permanent damage to the liver are unsubstantiated, and routine testing is considered unnecessary by some dermatologists. Blood triglycerides also need to be monitored. However, routine testing are part of the official guidelines for the use of the drug in many countries. Some press reports[weasel words] suggest that isotretinoin may cause depression, but, as of September 2005, there is no agreement in the medical literature as to the risk. The drug also causes birth defects if women become pregnant while taking it or take it while pregnant. For this reason, female patients are required to use two separate forms of birth control or vow abstinence while on the drug. Because of this, the drug is supposed to be given to females as a last resort after milder treatments have proven insufficient. Restrictive rules (see iPledge program) for use were put into force in the USA beginning in March 2006 to prevent misuse, causing occasioned widespread editorial comment.[27] Anti-inflammatories Nicotinamide, (vitamin B3) used topically in the form of a gel, has been shown in a 1995 study to be of comparable efficacy to topical clindamycin used for comparison.[28] Topical nicotinamide is available both on prescription and over-the-counter. The property of topical nicotinamide's benefit in treating acne seems to be its anti-inflammatory nature. It is also purported to result in increased synthesis of collagen, keratin, involucrin and flaggrin, and may also, according to a cosmetic company, be useful for reducing skin hyperpigmentation (acne scars), increasing skin moisture and reducing fine wrinkles.[29] Rofecoxib was shown to improve premenstrual acne vulgaris in a placebo-controlled study, although this drug has since been withdrawn.[30] Naproxen or ibuprofen[31] are used for some moderate acne cases for their anti-inflammatory effects. Calendula in suspension is used as an anti-inflammatory agent.[32] [edit] Procedures [edit] Dermabrasion Dermabrasion is a cosmetic medical procedure in which the surface of the skin is removed by abrasion (sanding). It is used to remove sun-damaged skin and to remove or lessen scars and dark spots on the skin. The procedure is very painful and usually requires a general anaesthetic or "twilight anaesthesia", in which the patient is still partly conscious.[33] Afterward, the skin is very red and raw-looking, and it takes several months for the skin to regrow and heal. Dermabrasion is useful for scar removal when the scar is raised above the surrounding skin, but is less effective with sunken scars. In the past, dermabrasion was done using a small, sterilized, electric sander. In the past decade, it has become more common to use laser dermabrasion using CO2, Er:YAG laser or a combination of both for the treatment of acne scars. Indications for CO2 laser treatment include previous non erythematous and non-proliferative hypertrophic scars, atrophic acne scars and burn scars.[34] Laser dermabrasion is much easier to control, much easier to gauge, and is practically bloodless compared to classic dermabrasion. Microdermabrasion comes from the above mentioned technique dermabrasion. Microdermabrasion is a more natural skin care that is a gentler, less invasive technology for doing an exfoliation on the skin. The goal of the microdermabrasion is to eliminate the superficial layer of the skin called the epidermis. If the surface of the abraded skin is touched, a roughness of the skin will be noticed. The roughness is keratinocytes, which are better hydrated than the surface corneocytes. Keratinocytes appear in the basal layer from the proliferation of keratinocyte stem cells. They are pushed up through the cells of the epidermis, experiencing gradual specialization until they reach the stratum corneum where they form a layer of dead, flattened, strongly keratinized cells called squamous cells. This layer creates an efficient barrier to the entry of foreign matter and infectious elements into the body and reduces moisture loss. Keratinocytes are shed and restored continuously from the stratum corneum. The time of transit from basal layer to shedding is generally one month. Corneocytes are cells derived from keratinocytes in the late stages of terminal specialization of squamous epithelia. The microdermabrasion is done to eliminate some of the corneocytes. These cells are responsible for the impermeability of the skin. The minimizing or elimination of scars, skin lesions, blotchiness and stretch marks from the skin can be an easy process with the use of skin exfoliation. The result depends on how well the procedure known as "skin remodeling" works. Results are optimal and fewer treatments are needed with more recent and/or superficial scars. Still, microdermabrasion can be used on scars that showed up during puberty or many years later. [edit] Phototherapy [edit] 'Blue' and red light Light exposure has long been used as a short term treatment for acne. Recently, visible light has been successfully employed to treat mild to moderate acne (phototherapy or deep penetrating light therapy) - in particular intense violet light (405-420 nm) generated by purpose-built fluorescent lighting, dichroic bulbs, LEDs or lasers. Used twice weekly, this has been shown to reduce the number of acne lesions by about 64%[35] and is even more effective when applied daily. The mechanism appears to be that a porphyrin (Coproporphyrin III) produced within P. acnes generates free radicals when irradiated by 420 nm and shorter wavelengths of light.[36] Particularly when applied over several days, these free radicals ultimately kill the bacteria.[37] Since porphyrins are not otherwise present in skin, and no UV light is employed, it appears to be safe, and has been licensed by the U.S. FDA.[38][39] It seems that the treatment works even better if used with a mixture of the violet light and red visible light (660 nanometer), resulting in a 76% reduction of lesions after three months of daily treatment for 80% of the patients;[40] and overall clearance was similar or better than benzoyl peroxide. Unlike most of the other treatments, few if any negative side-effects are typically experienced, and the development of bacterial resistance to the treatment seems very unlikely. After treatment, clearance can be longer-lived than is typical with topical or oral antibiotic treatments; several months is not uncommon. The equipment or treatment, however, is relatively new and reasonably expensive to buy initially, although the total cost of ownership can be similar to many other treatment methods (such as the total cost of benzoyl peroxide, moisturizer, washes) over a couple of years of use. [edit] Photodynamic therapy In addition, basic science and clinical work by dermatologists Yoram Harth and Alan Shalita and others has produced evidence that intense blue/violet light (405-425 nanometer) can decrease the number of inflammatory acne lesion by 60-70% in four weeks of therapy, in particular, when the P. acnes is pretreated with delta-aminolevulinic acid (ALA), which increases the production of porphyrins. However this photodynamic therapy is controversial and not published in a peer-reviewed journal. A phase II trial, while it showed improvement occurred, failed to show improved response compared to the blue/violet light alone.[41] [edit] Laser treatment Laser surgery has been in use for some time to reduce the scars left behind by acne,[42] but research has been done on lasers for prevention of acne formation itself. The laser is used to produce one of the following effects: * to burn away the follicle sac from which the hair grows * to burn away the sebaceous gland, which produces the oil * to induce formation of oxygen in the bacteria, killing them Since lasers and intense pulsed light sources cause thermal damage to the skin, there are concerns that laser or intense pulsed light treatments for acne will induce hyperpigmented macules (spots) or cause long-term dryness of the skin. In the United States, the FDA has approved several companies, such as Candela Corp., to use a cosmetic laser for the treatment of acne. However, efficacy studies have used very small sample sizes (fewer than 100 subjects) for periods of six months or less, and have shown contradictory results.[43] Also, laser treatment being relatively new, protocols remain subject to experimentation and revision,[44] and treatment can be quite expensive. Also, some Smoothbeam laser devices had to be recalled due to coolant failure, which resulted in painful burn injuries to patients.
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  • Scar From Wikipedia, the free encyclopedia Jump to: navigation, search "Scars" redirects here. For the 1998 video game, see S.C.A.R.S. (video game). "Scarring" redirects here. For the act of inflicting scars, see Scarification. This article is about scar tissue. For other uses, see Scar (disambiguation). Scar Classification and external resources A minor scar from a cut to the forearm, approx. one year since the wound. ICD-10 L90.5 MeSH D002921 Scars (also called cicatrices) are areas of fibrous tissue (fibrosis) that replace normal skin (or other tissue) after injury. A scar results from the biologic process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g. after accident, disease, or surgery) results in some degree of scarring. An exception to this is animals with regeneration, which do not form scars and the tissue will grow back exactly as before. Scar tissue is composed of the same protein (collagen) as the tissue that it replaces,[1] but instead of a random basketweave formation of the collagen fibers found in normal tissue,[1] the collagen cross-links and forms a pronounced alignment in a single direction.[1] This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat glands and hair follicles do not grow back within scar tissue. A myocardial infarction, commonly known as a heart attack, causes scar formation in the heart muscle, which leads to loss of muscular power and possibly heart failure. However, there are some tissues (e.g. bone) that can heal without any structural or functional deterioration. Contents [hide] * 1 Etymology * 2 How scarring occurs * 3 Scar types o 3.1 Hypertrophic o 3.2 Atrophic o 3.3 Stretch marks * 4 Treatments o 4.1 Needling o 4.2 Pressure dressing o 4.3 Steroids o 4.4 Silicone sheeting and gel o 4.5 Dermabrasion o 4.6 Collagen injections o 4.7 Laser surgery & resurfacing o 4.8 Surgery o 4.9 Radiotherapy o 4.10 Chemical peels o 4.11 Over the counter topical remedies o 4.12 Experimental * 5 Intentional scarring * 6 See also * 7 References * 8 External links [edit] Etymology First attested in English in late 14th century, the word scar derives from Old French "escharre", via Late Latin "eschara",[2] ultimately from Greek "ἐσχάρα" (eskhara), meaning "hearth, fire-place", but in medicine "scab, eschar on a wound caused by burning or otherwise".[3][4] [edit] How scarring occurs Hypertrophic scarring one year after Road rash on the left, and the original wound on the right. A scar is a result of the body's evolved patch up reaction after injury on many tissues. Any injury does not become a scar until the wound has completely healed; this can take many months. To begin to patch the defect a provisional clot is created; this first layer is not scar. The wounded body tissue then over-expresses collagen. This collagen over expression cross-links the fiber arrangement inside the collagen. This densely-packed collagen, morphing into an inelastic whitish collagen[5] scar wall, blocks off regeneration and, as a result, the new tissue that is generated will have a different texture and quality than the surrounding non-wounded tissue. This prolonged collagen-producing process results in a fortuna scar. The scarring is created by fibroblast proliferation,[5] which reacts to the clot.[6] To mend the damage, fibroblasts slowly form the collagen scar. The fibroblast proliferation is circular[7] and cyclically, the fibroblast proliferation lays down thick whitish collagen[5] inside the matrix, resulting in the packed abundant production of collagen on the fibers[5][6][8] giving scars their uneven texture. Over time, the fibroblasts continue to crawl around the matrix, adjusting more fibers and, in the process, the scarring settles and becomes stiff.[9] This fibroblast proliferation also contracts the tissue.[7][10] In non-wounded tissue, these fibers are not over expressed with thick collagen and do not contract. As well as the fibroblast proliferation[5] there is prolonged inflammation. Redness that often follows an injury to the skin is not a scar, and is generally not permanent (see wound healing). The time it takes for this redness to dissipate may, however, range from a few days to, in some serious and rare cases, a few years.[citation needed] Scars form differently based on the location of the injury on the body and the age of the person who was injured.[citation needed] The worse the initial damage is, the worse the scar will generally be.[citation needed] Skin Scars: Skin scars occur when the dermis (the deep, thick layer of skin) is damaged. Most skin scars are flat and leave a trace of the original injury that caused them.[citation needed] Stable forms of topical vitamin C have been shown to improve collagen formation.[11] Recent research has also implicated the gene product osteopontin in scarring and The University of Bristol have developed a gel that inhibits the process.[12][13] Transforming Growth Factors (TGF) play a critical role in scar development and current research is investigating the manipulation of these TGFs for drug development to prevent scarring from the emergency adult wound-healing process. As well, a recent American study implicated the protein Ribosomal s6 kinase (RSK) in the formation of scar tissue and found that the introduction of a chemical to counteract RSK could halt the formation of Cirrhosis. This treatment also has the potential to reduce or even prevent altogether other types of scarring.[14] [edit] Scar types The collagen over expression in scarring can be over expressed in different amounts with varying results. Collagen over expression types include: hypertrophic and keloid[15] scars, both of which experience excessive stiff collagen bundled growth over extending the tissue, blocking off regeneration of tissues. Atrophic scarring (sunken scarring) also has an over expression of collagen blocking of regeneration, this scar type is sunken, the collagen bundles do not over extend the tissue. Stretch marks (striae) are regarded as scars to some. [edit] Hypertrophic Hypertrophic scars occur when the body overproduces collagen, which causes the scar to be raised above the surrounding skin. Hypertrophic scars take the form of a red raised lump on the skin. Keloid scars are a more serious form of scarring, because they can carry on growing indefinitely into a large, tumorous (although benign) neoplasm.[15] Hypertrophic scars are often distinguished from keloid scars by their lack of growth outside the original wound area, but this commonly taught distinction can lead to confusion.[15] All keloid scars are hypertrophic[15] but "only a small percentage of large scars" are keloid.[15] Phenotypic differences exist between keloid scars and hypertrophic scars.[15] Keloid scars can occur on anyone, but they are most common in dark-skinned people.[16] Keloid scars can be caused by surgery, an accident, by acne or, sometimes, from body piercings. In some people, keloid scars form spontaneously. Although they can be a cosmetic problem, keloid scars are only inert masses of collagen and therefore completely harmless and non-cancerous. However, they can be itchy or painful in some individuals. They tend to be most common on the shoulders and chest. [edit] Atrophic An atrophic scar takes the form of a sunken recess in the skin, which has a pitted appearance. These are caused when underlying structures supporting the skin, such as fat or muscle, are lost. This type of scarring is associated with acne, chickenpox, other diseases, surgery or accidents. [edit] Stretch marks Stretch marks (technically called striae) are also a form of scarring. These are caused when the skin is stretched rapidly (for instance during pregnancy, significant weight gain or adolescent growth spurts), or when skin is put under tension during the healing process, (usually near joints). This type of scar usually improves in appearance after a few years.[citation needed] [edit] Treatments According to the American Academy of Dermatology, no scar can be completely removed[17] although in some cases healing can occur without scarring such as healing in embryos, healing without injury (regeneration), and some animals. It also depends on race. Eurasians or asians can have it completely removed and some Africans can.[18] As of 2004[update] no prescription drugs for the treatment or prevention of scars were available.[19] Atrophic Scarring occurring after surgical procedures or trauma is a common cosmetic problem for patients. Atrophic scars, which present as topographical depressions, result when dermal collagen and connective tissue production during the physiologic wound-healing process inadequately compensate for the tissue loss present after injury. Wound tension, tissue apposition, individual variations in wound healing, and scar contraction are all factors that contribute to the creation of a depressed, atrophic scar. With varying success, numerous ablative, nonablative, and fractional devices have been used to stimulate neocollagenesis and dermal remodeling in an attempt to improve the appearance of atrophic scars.[20] An alternative way to remove scars is to dissolve them with enzymes. According to Singh, Ratner etal and Lee, Bee Venom Therapy (BVT) is useful in diminishing scars. They explain when scars are stung they are broken down, softened and faded by substances in the venom.[21][22][23] (Bee sting image: Before and After).[24] Semiocclusive ointments (e.g. petrolatum-based), silicone gel sheeting and steroid injections have a widely-accepted role in general scar treatment,.[25] In 1962, a paper supporting the use of a semiocclusive ointments to speed healing and reduce scarring was published, beginning a practice which is now "a cornerstone of wound care" and the beginning of the discovery of the effectiveness of occlusive methods (ointments, occlusive dressings, silicones).[26] The effectiveness of silicone gel over nonsilicone gel was initially seen as controversial as no significant differences were noted when comparing silicone vs non silicone dressings.[26] It is now more accepted that the silicone itself is not a biologically active part of scar formation, it is the hydration silicone (and other occlusive dressings) offer. In 2002, Mustoe et al. in Vol 110. No 2 of Plastic and Reconstructive Surgery offer the International Recommendations on Scar Management and state, a "primary role for silicone gel sheeting and (corticosteroid injections) for the management of a wide variety of abnormal scars". Corticosteroid therapy by injection into the scars was also introduced in the 1960s. From the early 1970s pressure garment therapy was introduced for widespread burn scars, and silicone gel sheets from the 1980s.[27] In 1971 Moss & Clifford, pro