08.02.2016
A UV lamp is a lamp specifically designed to emit light at the ultraviolet wavelength, which is generally not able to be seen by humans without special equipment.
In addition to these entertainment and cosmetic applications, a UV lamp can also be used as a treatment tool for a number of different illnesses. I have a very old copy of The Womanly Art of Breastfeeding, and it suggests that for sore nipples, you should either expose them to sunlight or (I think) use a UV lamp. I’ve never understood people who go to tanning salons to sit under these lamps and get their tans. Erythropoietic protoporphyria is caused by UV light intolerance, and can be treated by afamelanotide. Ultraviolet (UV) light is part of the electromagnetic spectrum between visible light and X-rays.
Ultraviolet light has lethal effects on most species of bacteria and causes damage to all bacteria. In terrariums, these lamps are used so that plants and animals, especially reptiles, get enough of the required UV light they may need each day. At amusement parks and other places, an ultraviolet lamp can be used as a black light to create unusual glowing effects. Many tanning beds use such lamps to give artificial tans because UV light is what actually tans the skin in the natural environment.
While most UV light therapeutic tools are considered alternative forms of medicine, the use of an ultraviolet lamp, or lamps, to treat seasonal affective disorder, a mental illness, has been accepted in many mainstream practices. Apparently the UV rays help cracked nipples heal! I doubt you would find a lot of doctors recommending that these days! Even without knowledge of the science behind it, I’ve always felt that there was something that was inherently dangerous about the whole thing. This range is absorbed by DNA and RNA (genetic molecules) in micro-organisms and leads to their inactivation (‘killing’) by inhibiting their ability to replicate.
It is called “vacuum UV” since UV light in this range is strongly absorbed by water or oxygen in air and can thus only exist in vacuum. Ultraviolet (UV) light is nonionizing short wavelength radiation that falls between 4nm and 400nm in the visible spectrum.
For example, it is possible it will also produce visible light, but it can also operate using a black light. These effects can also help reflect very vibrant colors, which have glowing phosphors that often react with invisible UV light. However, the tanning beds can offer UV light at a much higher concentration, thus quickening the time it takes to receive the desired tan level. The theory behind the treatment for the seasonal disorder is that humans also need a certain amount of UV light and that may not be available in sufficient quantities during the winter months when people tend to spend less time outdoors and the days are shorter.
In order to get a tan, and then to maintain it, you have to go anywhere from once a week to a few times a week.
The danger is especially potent for those who use tanning beds, according to the American Medical Association, which states that the beds do increase the risk for cancer.
Ultraviolet light is longer than x-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV.
I told her maybe she should just learn to look at the world without ultraviolet light, but she is obsessive compulsive in her cleaning habits, kind of like Felix in the Odd Couple. UV light is routinely used to sterilize surfaces such as work areas under clean benches used for the innoculation of cultures. Ultraviolet light is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the colour violet.False-color image of the Sun's corona as seen in deep ultraviolet by the Extreme ultraviolet Imaging Telescope. I think if you need a tan, our sun is a better source of energy for that, but even there you need to be careful and use the right kind of skin protection. UV light is found in sunlight and is emitted by electric arcs and specialized lights such as black lights. UV radiation at 260 nm is the most effective against microorganisms because DNA absorbs the most UV light at this wavelength.
As an ionizing radiation it can cause chemical reactions, and causes many substances to glow or fluoresce.
These form when a covalent bond forms between two adjacent thymine or cytosine molecules in a DNA strand. In 1801 the German physicist Johann Wilhelm Ritter made the hallmark observation that invisible rays just beyond the violet end of the visible spectrum were especially effective at darkening silver chloride-soaked paper. Dimers cause the DNA to become deformed which does not allow DNA polymerase to replicate DNA strands pas the site of dimerization. He called them "de-oxidizing rays" to emphasize their chemical reactivity and to distinguish them from "heat rays" at the other end of the visible spectrum. The simpler term "chemical rays" was adopted shortly thereafter, and it remained popular throughout the 19th century. The terms chemical and heat rays were eventually dropped in favor of ultraviolet and infrared radiation, respectively.Entomologist using a UV light for collecting beetles in the Paraguayan Chaco.
The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is strongly absorbed by air, was made in 1893 by the German physicist Victor SchumannOrigin of term ultraviolet light.The name means "beyond violet" (from Latin ultra, "beyond"), violet being the color of the shortest wavelengths of visible light. In the long-wave limit of this region, roughly 150–200 nm, the principal absorber is the oxygen in air.
Work in this region can be performed in an oxygen free atmosphere, pure nitrogen being commonly used, which avoids the need for a vacuum chamber.
Fluorescent black lights are typically made in the same fashion as normal fluorescent lights except that only one phosphor is used and the normally clear glass envelope of the bulb may be replaced by a deep-bluish-purple glass called Wood's glass, a nickel-oxide–doped glass, which blocks almost all visible light above 400 nanometers.
The colour of such lamps is often referred to in the trade as "blacklight blue" or "BLB." This is to distinguish these lamps from "bug zapper" blacklight ("BL") lamps that don't have the blue Wood's glass. While "black lights" do produce light in the UV range, their spectrum is confined to the longwave UVA region. Unlike UVB and UVC, which are responsible for the direct DNA damage that leads to skin cancer, black light is limited to lower energy, longer waves and does not cause sunburn. However, UVA is capable of causing damage to collagen fibers and destroying vitamin A in skin.
A black light may also be formed by simply using Wood's glass instead of clear glass as the envelope for a common incandescent bulb. Though it remains a cheaper alternative to the fluorescent method, it is exceptionally inefficient at producing UV light (less than 0.1% of the input power) owing to the black body nature of the incandescent light source. Incandescent UV bulbs, due to their inefficiency, may also become dangerously hot during use.
More rarely still, high power (hundreds of watts) mercury vapor black lights can be found which use a UV emitting phosphor and an envelope of Wood's glass. These lamps are used mainly for theatrical and concert displays and also become very hot during normal use. Some UV fluorescent bulbs specifically designed to attract insects for use in bug zappers use the same near-UV emitting phosphor as normal blacklights, but use plain glass instead of the more expensive Wood's glass. Plain glass blocks less of the visible mercury emission spectrum, making them appear light blue to the naked eye. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm. The onset of vacuum UV, 200 nm, is defined by the fact that ordinary air is opaque below this wavelength. This opacity is due to the strong absorption of light of these wavelengths by oxygen in the air. Pure nitrogen (less than about 10 ppm oxygen) is transparent to wavelengths in the range of about 150–200 nm. This has wide practical significance now that semiconductor manufacturing processes are using wavelengths shorter than 200 nm.
By working in oxygen-free gas, the equipment does not have to be built to withstand the pressure differences required to work in a vacuum.
Some other scientific instruments, such as circular dichroism spectrometers, are also commonly nitrogen purged and operate in this spectral region. Extreme UV is characterized by a transition in the physics of interaction with matter: wavelengths longer than about 30 nm interact mainly with the chemical valence electrons of matter, while wavelengths shorter than that interact mainly with inner shell electrons and nuclei. XUV is strongly absorbed by most known materials, but it is possible to synthesize multilayer optics that reflect up to about 50% of XUV radiation at normal incidence.


A positive effect of UVB exposure is that it induces the production of vitamin D in the skin. It has been estimated that tens of thousands of premature deaths occur in the United States annually from a range of cancers due to vitamin D deficiency.
Another effect of vitamin D deficiency is poor absorption of calcium which can lead to bone diseases. An appropriate amount of UVB (which varies according to skin color) leads to a limited amount of direct DNA damage.
This tan occurs with a 2 day lag phase after irradiation, but it is much less harmful and long lasting than the one obtained from UVA.
In humans, prolonged exposure to solar UV radiation may result in acute and chronic health effects on the skin, eye, and immune system. However the most deadly form - malignant melanoma - is mostly caused by the indirect DNA damage (free radicals and oxidative stress).
Little attention has been given to UVC rays in the past since they are filtered out by the atmosphere.
The toxic effects of UV from natural sunlight and therapeutic artificial lamps are a major concern for human health. The major acute effects of UV irradiation on normal human skin comprise sunburn inflammation erythema, tanning, and local or systemic immunosuppression. In the past, UVA was considered less harmful, but today it is known that it can contribute to skin cancer via indirect DNA damage (free radicals and reactive oxygen species). UVA does not damage DNA directly like UVB and UVC, but it can generate highly reactive chemical intermediates, such as hydroxyl and oxygen radicals, which in turn can damage DNA. Because it does not cause reddening of the skin (erythema) it cannot be measured in SPF testing. There is no good clinical measurement for blockage of UVA radiation, but it is important that sunscreen block both UVA and UVB. Some scientists blame the absence of UVA filters in sunscreens for the higher melanoma-risk that was found for sunscreen users.Ultraviolet photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent Thymine bases bond with each other, instead of across the "ladder".
The radiation excites DNA molecules in skin cells, causing aberrant covalent bonds to form between adjacent cytosine bases, producing a dimer. When DNA polymerase comes along to replicate this strand of DNA, it reads the dimer as "AA" and not the original "CC".
This is a mutation, which can result in cancerous growths and is known as a "classical C-T mutation". The mutations that are caused by the direct DNA damage carry a UV signature mutation that is commonly seen in skin cancers. As a defense against UV radiation, the amount of the brown pigment melanin in the skin increases when exposed to moderate (depending on skin type) levels of radiation; this is commonly known as a sun tan.
The purpose of melanin is to absorb UV radiation and dissipate the energy as harmless heat, blocking the UV from damaging skin tissue. UVA gives a quick tan that lasts for days by oxidizing melanin that was already present and triggers the release of the melanin from melanocytes. UVB yields a tan that takes roughly 2 days to develop because it stimulates the body to produce more melanin. However, sunscreen chemicals can not dissipate the energy of the excited state as efficiently as melanin and therefore the penetration of sunscreen ingredients into the lower layers of the skin is increasing the amount of free radicals and ROS. In the US, the Food and Drug Administration is considering adding a star rating system to show UVA protection. Some sunscreen lotions now include compounds such as titanium dioxide which helps protect against UVA rays. Cantaloupe extract, rich in the compound superoxide dismutase (SOD), can be bound with gliadin to form glisodin, an orally-effective protectant against UVB radiation.
Five sunscreen ingredients have been shown to protect mice against skin tumors (see sunscreen).
However, some sunscreen chemicals produce potentially harmful substances if they are illuminated while in contact with living cells. The amount of sunscreen which penetrates through the stratum corneum may or may not be large enough to cause damage.
In one study of sunscreens, the authors write:The question whether UV filters acts on or in the skin has so far not been fully answered. Despite the fact that an answer would be a key to improve formulations of sun protection products, many publications carefully avoid addressing this question.In an experiment by Hanson et al.
In the first 20 minutes the film of sunscreen had a protective effect and the number of ROS species was smaller.
UV light is absorbed by molecules known as chromophores, which are present in the eye cells and tissues. Chromophores absorb light energy from the various wavelengths at different rates - a pattern known as absorption spectrum.
If too much UV light is absorbed, eye structures such as the cornea, the lens and the retina can be damaged. Protective eyewear is beneficial to those who are working with or those who might be exposed to ultraviolet radiation, particularly short wave UV. Given that light may reach the eye from the sides, full coverage eye protection is usually warranted if there is an increased risk of exposure, as in high altitude mountaineering. Mountaineers are exposed to higher than ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice. Most plastic lenses give more protection than glass lenses, because, as noted above, glass is transparent to UVA and the common acrylic plastic used for lenses is less so.
There are protective treatments available for eyeglass lenses that need it which will give better protection.
The problem appears as discoloration or fading, cracking and sometimes, total product disintegration if cracking has proceeded far enough.
Sensitive polymers include thermoplastics, such as polypropylene and polyethylene as well as speciality fibres like aramids.
UV absorption leads to chain degradation and loss of strength at sensitive points in the chain structure. Old and antique paintings such as watercolour paintings for example, usually need to be placed away from direct sunlight. Common window glass provides some protection by absorbing some of the harmful UV, but valuable artifacts need extra shielding.
Many museums place black curtains over watercolour paintings and ancient textiles, for example. UVAs can disappear over time, so monitoring of UVA levels in weathered materials is necessary. They are contrasted with physical "blockers" of UV radiation such as titanium dioxide and zinc oxide. Visa stamps and stickers on passports of visitors contain large and detailed seals invisible to the naked eye under normal lights, but strongly visible under UV illumination.
Passports issued by many nations have UV sensitive watermarks on all pages of the passport. Currencies of various countries' banknotes have an image, as well as many multicolored fibers, that are visible only under ultraviolet light.
A phosphorescent coating on the inside of the tubes absorbs the UV and converts it to visible light. Unshielded exposure of the skin or eyes to mercury arc lamps that do not have a conversion phosphor is quite dangerous. Because the ozone layer blocks many UV frequencies from reaching telescopes on the surface of the Earth, most UV observations are made from space. Many fruits, flowers, and seeds stand out more strongly from the background in ultraviolet wavelengths as compared to human color vision. Scorpions glow or take on a yellow to green color under UV illumination thus assisting in the control of these sometimes fatally venomous arachnids. Many birds have patterns in their plumage that are invisible at usual wavelengths but observable in ultraviolet, and the urine and other secretions of some animals, including dogs, cats, and human beings, is much easier to spot with ultraviolet. Urine trails of rodents can be detected by pest control technicians for proper treatment of infested dwellings.


Many insects use the ultraviolet wavelength emissions from celestial objects as references for flight navigation. They are attracted to the UV light, and are killed using an electric shock, or trapped once they come into contact with the device.
Pet urine deposits in carpeting or other hard surfaces can be detected for accurate treatment and removal of mineral tracers and the odor causing bacteria that feeds on proteins within.
Many substances, such as proteins, have significant light absorption bands in the ultraviolet that are of use and interest in biochemistry and related fields. UVB phototherapy does not require additional medications or topical preparations for the therapeutic benefit; only the light exposure is needed. However, phototherapy can be effective when used in conjunction with certain topical treatments such as anthralin, coal tar, and Vitamin A and D derivatives, or systemic treatments such as methotrexate and soriatane. Typical treatment regimes involve short exposure to UVB rays 3 to 5 times a week at a hospital or clinic, and up to 30 or more sessions may be required before results are noticeable.
Almost all of the conditions that respond to UVB light are chronic problems, so continual treatment is required to keep those problems in check. Side effects may include itching and redness of the skin due to UVB exposure, and possibly sunburn, if patients do not minimize exposure to natural UV rays during treatment days. There is no link between an increase in the patient's risk for skin cancer and the proper use of UVB phototherapy.
The light allows chemical reactions to take place in the photoresist, and after development (a step that either removes the exposed or unexposed photoresist), a geometric pattern which is determined by the mask remains on the sample.
Further steps may then be taken to "etch" away parts of the sample with no photoresist remaining. Degradation of insulation of electrical apparatus or pollution causes corona, wherein a strong electric field ionizes the air and excites nitrogen molecules, causing the emission of ultraviolet radiation.
Although 185 nm is better absorbed by DNA, the quartz glass used in commercially-available lamps, as well as environmental media such as water, are more opaque to 185 nm than 254 nm (C. UV light at these germicidal wavelengths causes adjacent thymine molecules on DNA to dimerize, if enough of these defects accumulate on a microorganism's DNA its replication is inhibited, thereby rendering it harmless (even though the organism may not be killed outright). Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in drinking water treatment. Solar water disinfection is the process of using PET bottles and sunlight to disinfect water.
New York City has approved the construction of a 2 billion gallon per day ultraviolet drinking water disinfection facility.
There are also several facilities under construction and several in operation that treat waste water with several stages of filters, hydrogen peroxide and UV light to bring the water up to drinking standards. NASA has examined the use of this technology, using titanium dioxide as catalyst, for breaking down harmful products in spacecraft waste water.
However, it was recently discovered that ultraviolet radiation can be somewhat effective for treating the microorganism Cryptosporidium. The findings resulted in the use of UV radiation as a viable method to treat drinking water.
Giardia in turn has been shown to be very susceptible to UV-C when the tests were based on infectivity rather than excystation. It has been found that protists are able to survive high UV-C doses but are sterilized at low doses.
Solar water disinfection (SODIS) has been extensively researched in Switzerland and has proven ideal to treat small quantities of water cheaply using natural sunlight. Contaminated water is poured into transparent plastic bottles and exposed to full sunlight for six hours. The sunlight treats the contaminated water through two synergetic mechanisms: UV-A irradiation and increased water temperature. In addition, public awareness regarding the dangers of food poisoning is also raising demand for improved food processing methods. UV light can be used to pasteurize fruit juices by flowing the juice over a high intensity ultraviolet light source.
UV detectors which are sensitive to UV light in any part of the spectrum respond to irradiation by sunlight and artificial light.
A burning hydrogen flame, for instance, radiates strongly in the 185 to 260 nanometer range and only very weakly in the IR region, while a coal fire emits very weakly in the UV band yet very strongly at IR wavelengths; thus a fire detector which operates using both UV and IR detectors is more reliable than one with a UV detector alone.
Virtually all fires emit some radiation in the UVC band, while the Sun's radiation at this band is absorbed by the Earth's atmosphere. The result is that the UV detector is "solar blind", meaning it will not cause an alarm in response to radiation from the Sun, so it can easily be used both indoors and outdoors. UV detectors are sensitive to most fires, including hydrocarbons, metals, sulfur, hydrogen, hydrazine, and ammonia.
Arc welding, electrical arcs, lightning, X-rays used in nondestructive metal testing equipment (though this is highly unlikely), and radioactive materials can produce levels that will activate a UV detection system.
The presence of UV-absorbing gases and vapors will attenuate the UV radiation from a fire, adversely affecting the ability of the detector to detect flames. When exposed to the correct energy and irradiance in the required band of UV light, polymerization occurs, and so the adhesives harden or cure. Applications include glass and plastic bonding, optical fiber coatings, the coating of flooring, UV Coating and paper finishes in offset printing, and dental fillings. Fast processes such as flexo or offset printing require high intensity light focused via reflectors onto a moving substrate and medium and high pressure Hg (mercury) or Fe (iron, doped) based bulbs are used which can be energised with electric arc or microwaves.
Currently, LED-based sources (focused and not focused) are achieving comparable power levels and are expected to become as important as Hg lamps in these applications.
The blue color of these lights, combined with the fluorescence of the skin, make it harder for intravenous drug users to find a vein.
The efficacy of these lights for that purpose has been questioned, with some suggesting that drug users simply find a vein outside the public restroom and mark the spot with a marker for accessibility when inside the restroom. This kind of damage is recognized by the body and as a defense against UV radiation the skin produces more melanin. Melanin dissipates the UV energy as harmless heat, and therefore it is an excellent photoprotectant. Sunscreen protects only against the direct DNA damage, but increases the indirect DNA damage - this causes the higher amount of melanoma that had been found repeatedly in sunscreen users compared to non-usersErasing EPROM modules with ultraviolet light.Some EPROM (erasable programmable read-only memory) modules are erased by exposure to UV radiation. These modules often have a transparent glass (quartz) window on the top of the chip that allows the UV radiation in. These have been largely superseded by EEPROM and flash memory chips in most devices.Preparing low surface energy polymersUV radiation is useful in preparing low surface energy polymers for adhesives.
Polymers exposed to ultraviolet light will oxidize thus raising the surface energy of the polymer. The technique involves taking pictures of the illegible papyruses using different filters in the infrared or ultraviolet range, finely tuned to capture certain wavelengths of light.
Thus, the optimum spectral portion can be found for distinguishing ink from paper on the papyrus surface.Ultraviolet light and lasersUltraviolet lasers have applications in industry (laser engraving), medicine (dermatology and keratectomy), free air secure communications and computing (optical storage). Used to replace conventional window glass, the installation surface area could be large, leading to potential uses that take advantage of the combined functions of power generation, lighting and temperature control. Also PEDOT-PSS solar cells is a ultraviolet (UV) light selective and sensitive photovoltaic cell easily fabricated. On the other hand, a nanocrystalline layer of Cu2O in the construction of photovoltaic cells increases their ability to utilize UV radiations for photocurrent generationNon-destructive Testing with ultraviolet light.Ultraviolet light of a specified spectrum and intensity is used to stimulate fluorescent dyes so as to highlight defects in a broad range of materials. UVB light causes thymine base pairs next to each other in genetic sequences to bond together into thymine dimers, a disruption in the strand which reproductive enzymes cannot copy (see picture above). This leads to frameshifting during genetic replication and protein synthesis, usually killing the organism.
As early prokaryotes began to approach the surface of the ancient oceans, before the protective ozone layer had formed, blocking out most wavelengths of UV light, they almost invariably died out. The few that survived had developed enzymes which verified the genetic material and broke up thymine dimer bonds, known as excision repair enzymes. Many enzymes and proteins involved in modern mitosis and meiosis are similar to excision repair enzymes, and are believed to be evolved modifications of the enzymes originally used to overcome UV light.



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Comments What is uv light source

  1. K_E_N_Z_O
    The intensity of the UV light never seem to last more than a couple of hours.
  2. Nacnoy_Snayper
    And makes it happen in a specified amount of time.