نتایج جستجو برای: uv exposure
تعداد نتایج: 372933 فیلتر نتایج به سال:
Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction o...
Humans undertake their daily activities in a number of different postures. This paper aims to compare the anatomical distribution of the solar erythemal UV to human legs for standing and sitting postures. The exposure ratios to the legs (ratio of the UV exposure to a particular anatomical site compared to the ambient) have been measured with UV dosimeters for standing and sitting postures of a ...
Degradation or polyethylene glycol has been studi ed by UV irradiation. A drastic change in the morphology from spherulite to rhythmic pattern has been observed under polarized light microscope when exposed to UV light. Molecular weight of PEG. Rr value and melting point have been recorded after UV exposure. On UV exposure there has also been a change in UV. IR and powder X-ray diffraction patt...
BACKGROUND Mushrooms are the only non-animal food source of vitamin D. Wild mushrooms have naturally high vitamin D(2) content, and cultivated mushrooms produce vitamin D(2) from ergosterol when exposed to supplementary UV-B during the post-harvest phase. OBJECTIVES This study investigated the effects of providing supplementary UV-B during the growth phase on vitamin D(2) formation and the in...
Purpose: To investigate the effects of topical application of Tagetes erectus hydroalcohol extract as a dermal antioxidant agent and evaluate its capacity to prevent ultraviolet (UV) –induced oxidative damage. Methods: The plant flower was extracted with aqueous ethanol (60 %). Female Lacca mice were divided into five groups of 24 animals each. Group I was un-irradiated control (neither UV expo...
Ultraviolet (UV) radiation is a prime environmental stressor that our epidermis exposed to on daily basis. To avert UV-induced damage, epidermal stem cells (EpSCs) become pigmented via process of heterotypic interaction between melanocytes and EpSCs, however the molecular mechanisms this are not well understood. In study we show function key chromatin regulator, Polycomb complex, was reduced up...
Hapten sensitization through UV-exposed skin induces systemic immune suppression, which is experimentally demonstrated by inhibition of contact hypersensitivity (CHS). Although this UV-induced effect has been shown to be mediated by inhibition of the afferent phase of the CHS, the UV effects on the efferent (elicitation) phase remain unknown. In this study, UV effects on endothelial ICAM-1 expr...
Basking by ectothermic vertebrates is thought to have evolved for thermoregulation. However, another beneficial effect of sunlight exposure, specifically the ultraviolet B (UV-B) component, includes endogenous production of vitamin D(3). In the laboratory, panther chameleons exhibited a positive phototaxis to greater visible, ultraviolet A (UV-A) and UV-B light. However, with equivalent high ir...
The purpose of this study was to investigate the adverse effects of ultraviolet (UV) radiation on earthworms. Earthworms that crawl out of the soil may die within a few hours after sunrise. This study shows that UV exposure can be lethal. In general, UV-B had a stronger damaging effect than UV-A. Different species of earthworms had different tolerances to UV exposure. In this study, Pontoscolex...
BACKGROUND Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo. Exposure to these chemicals, especially during prenatal development, is of concern. OBJECTIVES To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes. METHODS Prosp...
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