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Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun.Common symptoms in humans and other animals include red or reddish skin that is hot to the touch or painful, general fatigue, and mild dizziness.
Radiation therapy sources can cause beta burns during exposure of the patients. The sources can be also lost and mishandled, as in the Goiânia accident, during which several people had external beta burns and more serious gamma burns, and several died. Numerous accidents also occur during radiotherapy due to equipment failures, operator errors ...
Most people in the world depend on the sun to get vitamin D, [31] and elderly populations in low UVB countries experience higher rates of cancer. [32] There are not many foods that naturally have vitamin D. [33] Examples are cod liver oil and oily fish. If people cannot get sunlight, then they will need 1,000 IU of vitamin D per day to stay ...
This process of absorption works to reduce the risk of DNA damage and the formation of pyrimidine dimers. UVA light makes up 95% of the UV light that reaches earth, whereas UVB light makes up only about 5%. UVB light is the form of UV light that is responsible for tanning and burning. Sunscreens work to protect from both UVA and UVB rays.
Another transcription factor NF-κB, which is also activated by UV light, also increases the expression of MMP-9. The up-regulation of MMP can occur even after minimal exposure to UV, hence, exposure to UV radiation which is inadequate to cause sunburn can thus facilitate the degradation of skin collagen and lead to presumably, eventual photoaging.
Photochemistry such as pyrimidine dimer formation in DNA can happen through most of the UV band, including much of the band that is formally non-ionizing. Ultraviolet light induces melanin production from melanocyte cells to cause sun tanning of skin. Vitamin D is produced on the skin by a radical reaction initiated by UV radiation.
Ultraviolet (UV) light induces the formation of DNA damages including pyrimidine dimers (such as thymine dimers) and 6,4 photoproducts. These types of "bulky" damages are repaired by nucleotide excision repair .
One cause of cataracts is exposure to ultraviolet light. Provided the level of UV emission from lamps is within safe limits, and the lamp a sufficient distance away from the individual, there should be no increased risk of developing cataracts. Photophobia is a symptom of excessive sensitivity to light which affects 5 to 20% of the population ...