منابع مشابه
Sunlight and Vitamin D
Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years. During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3. Previtamin D3 and vitamin D3 also absorb UV B radiation and are converted into a variety of photoproducts some of which have unique b...
متن کاملSunlight and skin cancer
It is well known that chronic exposure to ultraviolet (UV) radiation present in sunlight is responsible for the induction of most nonmelanoma skin cancer (NMSC) in humans. Wavelengths in the UV-B (290–320 nm) region of the solar spectrum are absorbed into the skin, producing erythema, burns,and eventually skin cancer.NMSC is themost common type of human cancer. Recent surveys indicate that arou...
متن کاملColor Naming and Sunlight
Lindsey and Brown (2002) proposed an intriguing explanation for the existence and geographical distribution of languages that lack a distinct word for the color blue. Many such languages include blue in a color term that also encompasses green, yielding a green-or-blue (‘‘grue’’) term. Others include blue in a color term that also encompasses dark colors such as black, yielding a black-or-blue ...
متن کاملSunlight , UV , & Accelerated Weathering
Sunlight is an important cause of damage to plastics, textiles, paints, and other organic materials. Short wavelength ultraviolet light has long been recognized as being responsible for most of this damage2. Spectroradiometric measurements were made to quantify the wide variations in UV content of sunlight under the following conditions: direct summer sunlight, winter sunlight, sunlight filtere...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature
سال: 1991
ISSN: 0028-0836,1476-4687
DOI: 10.1038/353102c0