نتایج جستجو برای: uv radiation
تعداد نتایج: 299907 فیلتر نتایج به سال:
The Antarctic ozone hole is reported to develop annually in Austral spring since the late 1970s and results in increasing irradiances of solar UV-B radiation on the earth’s surface and in the aquatic environment (Farman et al. 1985, Häder et al. 1998). Exposure of organisms to enhanced UV-B radiation results in multiple damage, e.g. dimerisation of DNA molecules, formation of reactive oxygen sp...
DNA damage, provoked by ultraviolet (UV) radiation, evokes a cellular damage response composed of activation of stress signaling and DNA checkpoint functions. These are translated to responses of replicative arrest, damage repair, and apoptosis aimed at cellular recovery from the damage. p53 tumor suppressor is a central stress response protein, activated by multiple endogenous and environmenta...
Ultraviolet radiation-induced cataract has been believed to be associated with degradation of cellular components. We report that, in cultured human lens epithelial cells, UV radiation analogous to H2O2 treatment down-regulates desmosomal protein desmoglein-2. UV radiation induces generation of reactive oxygen species and transiently activates epidermal growth factor receptor, which in turn ind...
The harmful effects of ultraviolet radiation on aquatic animals, due to ozone layer reduction, have been long studied in recent years. Exposure of Rainbow Trout larvae (Oncorhynchus mykiss) to Ultraviolet-B radiation (UV-B) at different doses (68.75 µw/cm2 and 94.83 µw/cm2 as the minimum and maximum dose of UV-B in natural environment respectively) for 15 minutes once a day in dark condition in...
Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Flo...
In late May 2005 unusual high levels of solar ultraviolet radiation were observed over central Europe. In Northern Germany the measured irradiance of erythemally effective radiation exceeded the climatological mean by more than about 20%. An extreme low ozone event for the season coincided with high solar elevation angles and high pressure induced clear sky conditions leading to the highest val...
Excessive ultraviolet (UV) radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch...
BACKGROUND Phototesting is a technique that assesses the skin's sensitivity to UV radiation by determining the smallest dose of radiation capable of inducing erythema (minimal erythema dose [MED]) and anomalous responses to UV-A radiation. No phototesting protocol guidelines have been published to date. METHODOLOGY This was a multicenter prospective cohort study in which 232 healthy volunteer...
Ultraviolet-B radiation is an important component of the environment, acting as an ecophysiological factor with the potential to alter plant growth and photosynthesis. Plant response to UV-B is effectively regulated by photo protective mechanisms that dissipate excess radiation. At the morphological & physiological level these photo repair mechanisms and antioxidant responses mop up reactive ox...
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