نتایج جستجو برای: sun uv radiation
تعداد نتایج: 330509 فیلتر نتایج به سال:
Anti-reflective (AR) coatings provide numerous visual benefits to spectacle wearers. However, coating designers and manufacturers seem to have placed little or no emphasis on reflectance of wavelengths outside the visible spectrum. Ultraviolet (UV) radiation from sources behind the wearer can reflect from the back lens surface toward the wearer's eye. Various clear lens materials, with and with...
UV radiation is a well-documented human carcinogen, indisputably linked to the current continued increased rate of skin cancer. UV radiation is also responsible for cutaneous synthesis of vitamin (vit) D3, a substance that is then sequentially hydroxylated in the liver and kidney to yield 1,25(OH)2 vit D, a hormone critical for calcium homeostasis and skeletal maintenance. Because the UV action...
Time series observations at UV (Extreme Ultraviolet Imaging Telescope/Solar and Heliospheric Observatory) and X-ray (Soft X-Ray Telescope/Yohkoh) wavelengths reveal properties of the global solar corona that are not easily identiÐed in a single image. A median-Ðltering technique that rejects features varying with time is used to isolate background corona. The coronal hole boundaries, polar plum...
Exposure to natural sunlight, specifically solar ultraviolet (UV) radiation contributes to lifetime risks of skin cancer, eye disease, and diseases associated with vitamin D insufficiency. Improved knowledge of personal sun exposure patterns can inform public health policy; and help target high-risk population groups. Subsequently, an extensive number of studies have been conducted to measure p...
Psoriasis is a chronic inflammatory disease involving about 2-3% of the European population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV) radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun expo...
Exposure to UV radiation can cause skin damage; among UV rays UVB are commonly considered to be more important in inducing photoaging and skin cancer; however in recent years some authors have claimed an important role also for UVA that can concur with UVB to damage the skin. UVB rays have a wavelength between 280 and 320 nm and are responsible for immediate skin damage represented by erythema....
AIM Health benefits of adequate vitamin D levels in the blood include better bone health and a reduced incidence of a range of chronic diseases and infections. Ultraviolet (UV) radiation exposure from the sun is the main source of vitamin D; however, such exposure, especially from a young age, is also a potential risk factor for skin cancer. The current study examined the association of UV expo...
was the cause of their melanoma, seven (11%) blamed sunbed use and 10 more (16%) did not exclude the possibility that exposure to UV radiation was the cause of their melanoma (Table 1). Males attributed their melanoma directly to the sun or sunbeds more often (32%) than females (22%). Patients who were more susceptible to the sun (fairskinned, blue eyes, blond hair) and had been sunburned frequ...
This paper reviews briefly the evidence for an association between various measures of UV radiation (UVR) exposure and the development of cancer. Issues such as data quality, study design, measurement variation, comparability of studies, and quantification of UV exposure in relation to skin cancer are discussed. A range of exposure, based on skin type, might be appropriate: from 5 min a day thr...
Fitzpatrick skin phototypes were developed by Thomas B. Fitzpatrick in 1975 based on a persons skin color and responses to sun exposure in terms of degree of burning and tanning. Though subjective, Fitzpatrick skin typing has a proven diagnostic and therapeutic value. It has been most commonly used to analyze the sun sensitivity in population-based and case-control studies related to cause of ...
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