Tuesday, 23 February 2016

Literature Review

We were investigating on the UV radiation emitted from different light bulbs. We were trying to find out what are the traits and flaws of the various kinds of light bulbs and their safety level using the ratio between the amount of UV and light concentration. The bulb which emits the lowest amount of UV radiation but shines the brightest is the most desired bulb. Our aim is to educate people in a sense that allows them to select the safest bulb for their use, whether it is for mood lighting or commercial. By doing this, we can also tell whether the companies selling their bulbs are truly keeping their word. Some companies claim that their bulbs are the safest and most energy efficient or if they are the best regarding quality.What is the authenticity ratio of their words? Think about the number of bulbs in the world, various types may have various pros and cons, but not all of them may have the qualities which we value. Some light bulbs emit high amounts of UV radiation while giving strong light; some consume high amounts of energy while having low UV emissions. We hope to give the right information and aid consumers by informing them which bulbs are perfect and safest for their daily use.

   Safety, what do we think of the word and it’s variations. As a noun, a safe is some basically vault or box that one keeps one's valuables in to keep them, well, safe. However, the definition we are looking at is safe from harm. This matches with our aim to make sure that the consumers are safe from the harm of UV radiation even in the comforts of their home and are having financial safety while buying bulbs. UV radiation is emitted from the light bulbs, the very same thing which sunlight consists of, except that the UV is more concentrated. So does UV radiation cause cancer? Yes. In fact, most skin cancers are a direct result of exposure to the UV rays in sunlight. Both basal cell and squamous cell cancers tend to be found on sun-exposed parts of the body, and their occurrence is typically related to lifetime sun exposure. The risk of melanoma, a more serious but less common type of skin cancer, is also related to sun exposure, although perhaps not as strongly. Skin cancer has also been linked to exposure to some artificial sources of UV rays. Basal and squamous cell skin cancer: Many observational studies have found that basal and squamous cell skin cancers are linked to certain behaviors that put people in the sun, as well as a number of markers of sun exposure, such as spending time in the sun for recreation (including going to the beach)  Spending a lot of time in the sun in a swimsuit, living in an area with a high amount of sun. Having had serious sunburns in the past (with more sunburns linked to a higher risk)  Having signs of sun damage to the skin, such as liver spots, actinic keratoses (rough skin patches that can be precancerous), and solar elastosis (thickened, dry, wrinkled skin caused by sun exposure) on the neck Melanoma: Observational studies have also found links between certain behaviors and markers of sun exposure and melanoma of the skin, including:  Activities that lead to “intermittent sun exposure,” like sunbathing, water sports, and taking vacations in sunny places  Previous sunburns  Signs of sun damage to the skin, such as liver spots, actinic keratoses, and solar elastosis Other cancers: Because UV radiation does not penetrate deeply into the body, it would not be expected to cause cancer in internal organs, and most research has not found such links. However, some studies have shown possible links to some other cancers, including  merkel cell carcinoma (a less common type of skin cancer)  Cancer of the lip  Some types of eye cancer, such as melanoma of the eye and squamous cell carcinoma of the conjunctiva.
UV radiation also known as ultraviolet radiation is one form of energy coming from the sun. Ultraviolet radiation is a form of electromagnetic radiation, the main source of UV radiation is the sun, although it can also come from man-made sources such as tanning beds and welding torches. Continuous thermonuclear reactions in the sun’s core yield a wide spectrum of electromagnetic energy that radiates through space in all directions. This radiant energy is called electromagnetic because it is in the form of oscillating electric and magnetic fields. Electromagnetic radiation exhibits both wavelike ( oscillating field) and particle like (discrete packet ) properties. These discrete packets or quanta are called photons. Even though you may have only just started hearing about UV and the effects it has on you, it is nothing new. In fact, UV is as old as the earth itself. Cloudy days deceive many people into thinking the danger of UV radiation is minimal.  Clouds affect the strength of radiation reaching the ground in complex ways.  Most clouds block some UV radiation, but the degree of protection depends on the type and amount of cloud.  Some clouds can increase the UV intensity on the ground by reflecting and refracting the sun's rays.  People can also be caught unawares when a small break in an overcast deck of clouds allows a brief burst of intense radiation to reach the ground. Cold air can also be deceptive as the temperature is not directly related to UV intensity.  Skiers should take particular care as reflective snow on the ground, and high altitude raises the UV Index significantly relative to its value at sea level. UV is particularly useful in creating vitamin D, which is a group of vitamins found in liver and fish oils, essential for the absorption of calcium and the prevention of rickets in children and osteomalacia in adults. They include calciferol ( vitamin D2 ) and cholecalciferol ( vitamin D3 ).

Radiation is the emission of energy from any source. There are many types of radiation.Radiation exists across a spectrum from very high-energy radiation – like x-rays and gamma rays – to very low-energy radiation – like radio waves. UV rays have more energy than visible light, but not as much as x-rays. Higher energy UV rays often have enough energy to remove an electron from an atom or molecule, making them a form of ionizing radiation. Ionizing radiation can damage DNA in the cells in our body, which in turn may lead to cancer. However, because UV rays do not have enough energy to penetrate deeply into the body, their main effect is on the skin. Scientists often divide UV radiation into three wavelength ranges. UVA rays are the weakest of the UV rays. They can cause skin cells to age and can cause some indirect damage to cells’ DNA. UVA rays are linked to long-term skin damage such as wrinkles but are also thought to play a role in some skin cancers. UVB rays have slightly more energy than UVA rays. They can damage the DNA in skin cells directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers. UVC rays have more energy than the other types of UV rays. Fortunately, because of this, they react with ozone high in our atmosphere and do not reach the ground. Therefore, UVC rays are not normally a risk factor for skin cancer.However they can also come from some man-made sources, such as arc welding torches, mercury lamps, and UV sanitizing bulbs that kill bacteria and other germs such as in water, air, food, or on surfaces.

So how are people exposed to UV radiation? Sunlight is the main source of UV radiation, even though UV rays make up only a small portion of the sun’s rays. About 95% of the UV rays from the sun that reach the earth are UVA rays, with the remaining 5% being UVB rays. The strength of the UV rays reaching the ground depends on a number of factors, such as: Time of day: UV rays are strongest between 10 am and 4 pm.  Season of the year: UV rays are stronger during spring and summer months. This is less of a factor near the equator. Distance from the equator (latitude): UV exposure goes down as you get farther from the equator.  Altitude: More UV rays reach the ground at higher elevations.  Clouds: The effect of clouds can vary. Sometimes cloud cover blocks some UV from the sun and lowers UV exposure while some types of clouds can reflect UV and can increase UV exposure. What’s important to know is that UV rays can get through, even on a cloudy day.  Reflection off surfaces: UV rays can bounce off surfaces like water, sand, snow, pavement, or grass, leading to an increase in UV exposure.  Contents of the air: Ozone in the upper atmosphere, for example, filters out some UV radiation. The amount of UV exposure a person gets depends on the strength of the rays, the length of time the skin is exposed, and whether the skin is protected with clothing or sunscreen.

Besides nature, man has something to do about it too. Sunlamps and sunbeds (tanning beds and booths): The amount and type of UV radiation someone is exposed to from a tanning bed (or booth) depends on the specific lamps used in the bed, how long a person stays in the bed, and how many times the person uses it. Most modern UV tanning beds emit UVA rays mostly , with the rest being UVB.  Phototherapy (UV therapy): Some skin problems (such as psoriasis) are helped by treatment with UV light. For a treatment known as PUVA, a drug called a psoralen is given first. The drug collects in the skin and makes it more sensitive to UV. Then the patient is treated with UVA radiation. Another treatment option is the use of UVB alone (without a drug).  Black-light lamps: These lamps use bulbs that give off UV rays (mostly UVA). The bulb also gives off some visible light, but it has a filter that blocks most of that out while letting the UV rays through. These bulbs have a purple glow and are used to view the fluorescent material. Bug-zapping insect traps also use “black light” that gives off some UV rays, but the bulbs use a different filter that causes them to glow blue.  Mercury-vapor lamps: Mercury-vapor lamps can be used to light large public areas such as streets or gyms. They do not expose people to UV rays if they are working properly. They are made up of 2 bulbs: an inner bulb that emits light and UV rays, and an outer bulb that filters out the UV. UV exposure can only occur if the outer bulb is broken. Some mercury-vapor lamps are designed to turn themselves off when the outer bulb breaks. The ones that don’t have this feature are only supposed to be installed behind a protective layer or in areas where people would not be exposed if part of the bulb breaks.  High-pressure xenon and xenon-mercury arc lamps, plasma torches, and welding arcs: Xenon and xenon-mercury arc lamps are used as sources of light and UV rays for many things, such as UV “curing” (of inks, coatings, etc.), video projection, fiber optics, disinfection, to simulate sunlight (to test solar panels, for example), and even in some car headlights. Most of these, along with plasma torches and welding arcs, are mainly of concern regarding workplace UV exposure.

Are there any other health issues related to UV radiation? In addition, to cancer, exposure to UV rays can cause other health problems. UV rays, either from the sun or from artificial sources like tanning beds, can cause sunburn. In some people, exposure to UV rays can cause a rash or a type of allergic reaction. Exposure to UV rays can also cause premature aging of the skin and signs of sun damage such as liver spots, actinic keratosis, and solar elastosis. UV rays can also cause eye problems. They can cause the cornea (on the front of the eye) to become inflamed or burned. They can also lead to the formation of cataracts (clouding of the lens of the eye) and pterygium (tissue growth on the surface of the eye), both of which can impair vision. Exposure to UV rays can also weaken the immune system so that the body has a harder time fending off infections. This can lead to problems such as reactivation of herpes triggered by exposure to the sun or other sources of UV rays. It can also cause vaccines to be less effective. Some medications can make you more sensitive to UV radiation, making you more likely to get sunburned. Certain medical conditions can be made worse by UV radiation.

About UV rays and vitamin D Doctors are learning that vitamin D has many health benefits. It might even help lower the risk for some cancers. Human skin makes vitamin D naturally when it is exposed to UV rays from the sun. How much vitamin D it make depends on many things, including how old one is, how dark one's skin is, and how strong the sunlight is. At this time, doctors are not sure what the optimal level of vitamin D is. Much research has been done in this area. Whenever possible, it is better to get vitamin D from one's diet or vitamin supplements rather than from exposure to UV rays because dietary sources and vitamin supplements do not increase skin cancer risk, and are typically more reliable ways to get the amount needed.

Can one avoid exposure to UV radiation? UV rays in sunlight it is not possible (or healthy) to avoid sunlight completely, but there are ways to help ensure you are not getting too much sun. If one is going to be outside, simply staying in the shade, especially during midday hours, this is one of the best ways to limit UV exposure from sunlight. Protect the skin with clothing and wear a hat to protect one's head, face, and neck. Wear sunglasses that block UV to protect one's eyes and the skin around them and use sunscreen to help protect skin that is not covered with clothing.


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