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Vampire Research

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Xeroderma pigmentosum. Child suffering from xeroderma pigmentosum in Rukum, Nepal Xeroderma pigmentosum, or XP, is an autosomal recessive genetic disorder of DNA repair in which the ability to repair damage caused by ultraviolet (UV) light is deficient.[2]:574 In extreme cases, all exposure to sunlight must be forbidden, no matter how small; as such, individuals with the disease are often colloquially referred to as Children of the Night.[3] Multiple basal cell carcinomas (basaliomas) and other skin malignancies frequently occur at a young age in those with XP.

In fact, metastatic malignant melanoma and squamous cell carcinoma[4] are the two most common causes of death in XP victims. This disease involves both sexes and all races, with an incidence of 1:250,000 in the United States[5] and a gene frequency of 1:200. XP is roughly six times more common in Japanese people[4] than in other groups. Genetics[edit] Child affected with xerodema pigmentosum Types[edit] Symptoms[edit] Symptoms include: Treatment[edit] Pyrimidine dimers. DNA Lesion-Thymine Dimer Types of dimers[edit] Left: Spore photoproduct. Right: Cyclobutane pyrimidine dimer. A cyclobutane pyrimidine dimer (CPD) contains a four membered ring arising from the coupling of the C=C double bonds of pyrimidines.[4][5][6] Such dimers interfere with base pairing during DNA replication, leading to mutations. 6,4-photoproducts, or 6,4 pyrimidine-pyrimidones, occur at one third the frequency of CPDs but are more mutagenic.[7] Spore photoproduct lyase provides another enzymatic pathway for repair of thymine photodimers.[8] Mutagenesis[edit] Translesion polymerases frequently introduce mutations at pyrimidine dimers, both in prokaryotes (SOS mutagenesis) and in eukaryotes.

DNA repair[edit] Nucleotide excision repair is a more general mechanism for repair of lesions. References[edit] Jump up ^ David S. Cyclobutane photodimer. Sun tanning. A suntanned arm showing browner skin where it has been exposed. This pattern of tanning is often called a farmer's tan. Sun tanning or simply tanning is the process whereby skin color is darkened or tanned. It is most often a result of exposure to ultraviolet (UV) radiation from the sun or from artificial sources, such as a tanning bed. People who deliberately tan their skin by exposure to the sun engage in sun bathing. Some people use chemical products which can produce a tanning effect without exposure to ultraviolet radiation. Moderate exposure to the sun contributes to the production of vitamin D by the body, but excessive exposure to ultraviolet rays has negative health effects, including sunburn and increased risk of skin cancer, [1] as well as depressed immune system function and accelerated ageing of the skin.

Several cases of tanning addiction have been reported. The term "tanning" has a cultural origin, arising from the color tan. Tanning process[edit] UVA[edit] UVB[edit] The U.S. Thermoregulation. Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. This process is one aspect of homeostasis: a dynamic state of stability between an animal's internal environment and its external environment (the study of such processes in zoology has been called ecophysiology or physiological ecology). If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. For humans, this occurs when the body is exposed to constant temperatures of approximately 55 °C (131 °F), and any prolonged exposure (longer than a few hours) at this temperature and up to around 75 °C (167 °F) death is almost inevitable.

Occasionally the temperature of the urine as it leaves the urethra may be of use. More often the temperature is taken in the mouth, axilla, ear or groin. Classification of animals by thermal characteristics[edit]