نتایج جستجو برای: sun uv radiation
تعداد نتایج: 330509 فیلتر نتایج به سال:
Bright EUV sunspot plumes have been observed in five out of nine sunspot regions with the Coronal Diagnostic Spectrometer – CDS on SOHO. In the other four regions the brightest line emissions may appear inside the sunspot but are mainly concentrated in small regions outside the sunspot areas. These results are in contrast to those obtained during the Solar Maximum Mission, but are compatible wi...
Introduction: Xeroderma pigmentosum is an autosomal recessive disease with sun sensitivity, photophobia, early onset of freckling, and subsequent neoplastic changes on sun-exposed surfaces. There is cellular hypersensitivity to UV radiation and to certain chemicals in association with abnormal DNA repair. Patients with defective DNA nucleotide excision repair (NER) have defects in one of seven ...
Photodermatoses are skin conditions that are induced or exacerbated by electromagnetic radiation (including visible light, UV light, and infrared radiation) from the sun or artificial light sources. In Part 1 of this series we review current understanding of the pathophysiology of these processes and their classification. We also discuss technical aspects and the basic physics of photobiology a...
The widths of spectral lines in the ultraviolet (UV) and extreme ultraviolet (EUV) spectral regions that are formed in the solar transition region and corona are usually greater than the optically thin widths due to thermal Doppler broadening calculated under the assumption of ionization equilibrium. Although opacity can explain the widths of some lines, there are a host of optically thin lines...
All of the ultraviolet wave radiations, including UVA can alter the immune system of the skin. Scale cells cancer of the skin and malignant melanoma are caused by UVA radiation, but researchers insist more on the carcinogenetic effect of UVB spectrum. UVB spectrum is produced from the sun, sodium vapor lamp and electric and welding radiation of metal electrodes. In this study, the effect of UV ...
Sunlight contains ultraviolet radiation, which can cause the formation of free radicals. One plants that has potential to be used as sunscreen is jackfruit (Artocarpus heterophyllus Lamk). This research aimed determine sun stick leaf extract a UV-Protector exposed UV-B radiation. study two methods, namely in vitro and vivo. In vitromethod was carried out using spectro-photometric method analyze...
UV radiation is an important etiologic factor for skin cancer, including melanoma. Constitutive pigmentation and the ability to tan are considered the main photoprotective mechanism against sun-induced carcinogenesis. Pigmentation in the skin is conferred by epidermal melanocytes that synthesize and transfer melanin to keratinocytes. Therefore, insuring the survival and genomic stability of epi...
BACKGROUND Cumulative exposure to ultraviolet radiation (UV) is a risk factor for development of skin cancer. We estimated changes in knowledge, attitudes, and behaviors among Nevada school-age children following implementation of a program to decrease UV exposure. COMMUNITY CONTEXT The Nevada Cancer Coalition's Sun Smart Schools pilot program was implemented in 7 Nevada schools during the 20...
Several coronal bright points identified in a quiet region of the Sun from SOHO/EIT Fe XII images are found to have a time evolution from birth to decay which is extremely well correlated with the rise and fall of magnetic flux as determined from photospheric magnetograms made with the SOHO/MDI instrument. Radiative losses of the bright points are found to be much less than conductive losses bu...
All the people are exposed to solar ultraviolet radiation. Exposure to sun with living in an oxygen-rich atmosphere causes unwanted photodemage. Sunburned skin is a leading risk factor for melanoma and non-melanoma cancers. UV exposure causes immunosuppression via multiple mechanisms in the skin. In this review the main topic is to mention new or alternative ways of photoprotection. Sunscreens ...
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