Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet radiation from the Sun. Common symptoms in humans and other animals include: red or reddish skin, hot to the touch or painful, general fatigue, mild dizziness. Excessive UV radiation can be life-threatening in extreme cases. Excessive UV radiation is the leading cause of non-malignant skin tumors. Sunburn is an inflammatory response in the tissue triggered by direct DNA damage by UV radiation; when the cells' DNA is overly damaged by UV radiation, type I cell-death is triggered and the tissue is replaced. Sun protective measures including sunscreen and sun protective clothing are accepted to prevent sunburn and some types of skin cancer. Special populations, including children, are susceptible to sunburn and protective measures should be used to prevent damage. There is initial redness, followed by varying degrees of pain, proportional in severity to both the duration and intensity of exposure.
Other symptoms can include blistering, pruritus, peeling skin, nausea, fever and fainting. A small amount of heat is given off from the burn, caused by the concentration of blood in the healing process, giving a warm feeling to the affected area. Sunburns may be classified as partial thickness burns. Blistering is a sign of second degree sunburn. Minor sunburns cause nothing more than slight redness and tenderness to the affected areas. In more serious cases, blistering can occur. Extreme sunburns may require hospital care. A severe sunburn is sometimes called a "lobster burn" and in Australia and New England to turn "lobster" is to sunburn. Sunburn can occur in less than 15 minutes, in seconds when exposed to non-shielded welding arcs or other sources of intense ultraviolet light; the inflicted harm is not obvious. After the exposure, skin may turn red in as little as 30 minutes but most takes 2 to 6 hours. Pain is strongest 6 to 48 hours after exposure; the burn continues to develop for 1 to 3 days followed by peeling skin in 3 to 8 days.
Some peeling and itching may continue for several weeks. Ultraviolet radiation causes sunburns and increases the risk of three types of skin cancer: melanoma, basal-cell carcinoma and squamous-cell carcinoma. Of greatest concern is that the melanoma risk increases in a dose-dependent manner with the number of a person's lifetime cumulative episodes of sunburn, it has been estimated that over 1/3 of melanomas in the United States and Australia could be prevented with regular sunscreen use. Sunburn is caused by UV radiation, either from the sun or from artificial sources, such as tanning lamps, welding arcs, or ultraviolet germicidal irradiation, it is a reaction of the body to direct DNA damage from UVB light. This damage is the formation of a thymine dimer; the damage is recognized by the body, which triggers several defense mechanisms, including DNA repair to revert the damage and peeling to remove irreparably damaged skin cells, increased melanin production to prevent future damage. Melanin absorbs UV wavelength light, acting as a photoprotectant.
By preventing UV photons from disrupting chemical bonds, melanin inhibits both the direct alteration of DNA and the generation of free radicals, thus indirect DNA damage. However human melanocytes contain over 2,000 genomic sites that are sensitive to UV, such sites can be up to 170-fold more sensitive to UV induction of cyclobutane pyrimidine dimers than the average site These sensitive sites occur at biologically significant locations near genes. Sunburn causes an inflammation process, including production of prostanoids and bradykinin; these chemical compounds increase sensitivity to heat by reducing the threshold of heat receptor activation from 109 °F to 85 °F. The pain may be caused by overproduction of a protein called CXCL5. Skin type determines the ease of sunburn. In general, people with lighter skin tone and limited capacity to develop a tan after UV radiation exposure have a greater risk of sunburn; the Fitzpatrick's Skin phototypes classification describes the normal variations of skin responses to UV radiation.
Persons with type I skin have the greatest capacity to sunburn and type VI have the least capacity to burn. However, all skin types can develop sunburn. Fitzpatrick's skin phototypes: Type I: Pale white skin, burns does not tan Type II: White skin, burns tans with difficulty Type III: White skin, may burn but tans Type IV: Light brown/olive skin, hardly burns, tans Type V: Brown skin does not burn, tans Type VI: Black skin unlikely to burn, becomes darker with UV radiation exposureAge affects how skin reacts to sun. Children younger than six and adults older than sixty are more sensitive to sunlight. There are certain genetic conditions, for example xeroderma pigmentosum, that increase a person's susceptibility to sunburn and subsequent skin cancers; these conditions involve defects in DNA repair mechanisms which in turn decreases the ability to repair DNA, damaged by UV radiation. The risk of a sunburn can be increased by pharmaceutical products that sensitize users to UV radiation. Certain antibiotics, oral contraceptives, acne medications, tranquillizers have this effect.
The UV Index indicates the risk of getting a sunburn at location. Contributing factors include: The time of day. In most locations, the sun's rays are strongest between 10am and 4pm daylight saving ti
Skullbone is an unincorporated community in Gibson County, United States. It is located to the east of Bradford and is centered on Tennessee State Route 105, it was known as North Gibson and Skin Bone. The name was changed to Skullbone on April 26, 1898, when a United States Post Office opened there; the post office at Skullbone remained operational until December 24, 1903. The name has come into use as a reflection of local "bare-knuckle" fights held in the community, where strikes to the skull were common. Skullbone has long been known in local circles as "The Capital of the Kingdom of Skullbonia." The so-called "kingdom" is a vaguely defined area of northeastern Gibson County and, according to some, adjacent portions of neighboring counties. Hampton's Store, the only business operating in the community has elaborate murals painted on the side of the building depicting the Kingdom of Skullbonia's domain, bare-knuckle fighters, as well as declaring that there is a "Mayor's Office Upstairs," though it is unincorporated and has no elected council or mayor.
Another attraction that can be found in Skullbone is the famed signs which sit at the intersection of Skullbone Road and Tennessee State Route 105. These signs give the mileage from Skullbone to many major cities throughout the world such as Calcutta and Jerusalem, Israel as well as local and regional communities and cities like Bradford, Memphis
St George was an electoral district of the Legislative Assembly in the Australian state of New South Wales created in 1894 with the abolition of multi-member districts, from part of Canterbury and named after the St George district. In 1920, the electoral districts of St George and Hurstville were combined to create a new incarnation of St George, which elected five members by proportional representation; this was replaced by single member electorates, including parts of St George, Hurstville and Rockdale for the 1927 election. St George was abolished in 1930, being replaced by Arncliffe. Thomas Ley resigned to contest the federal seat of Barton at the 1925 election. Between 1920 and 1927 the Legislative Assembly was elected using a form of proportional representation with multi-member seats and a single transferable vote; the Parliamentary Elections Act, provided that casual vacancies were filled by the next unsuccessful candidate on the incumbent member's party list. William Bagnall had the most votes of the unsuccessful Nationalist candidates at the 1925 election and took his seat on 30 September 1925.
William Bagnall was elected in 1913 as the Labor member for St George, but defected to the Nationalists before this election. St George lost part of the district to Canterbury