نتایج جستجو برای: uv exposure
تعداد نتایج: 372933 فیلتر نتایج به سال:
The effects of ultraviolet (UV) radiation on ionizing radiation biodosimetry were studied in human tooth enamel samples using the technique of electron paramagnetic resonance (EPR) in X-band. For samples in the form of grains, UV-specific EPR spectra were spectrally distinct from those produced by exposure to gamma radiation. From larger enamel samples, the UV penetration depth was determined t...
Increasing evidence indicates that abnormal Cu2+ binding to Aβ peptides are responsible for the formation of soluble Aβ oligomers and ROS that play essential roles in AD pathogenesis. During studying the Cu2+-chelating treatment of Cu2+-bound Aβ42 aggregates, we found that UV light exposure pronouncedly enhances cytotoxicity of the chelator-treated and -untreated Cu2+-bound Aβ42 aggregates. Thi...
Psoriasis is a chronic inflammatory disease involving about 2–3% of the Norwegian 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 5 immune suppressive effect, but the relation between sun e...
The fraction and the distribution of the personal daily solar erythemal UV exposure were assessed for the shade provided by Australian gum trees in each of the four seasons to allow evaluation of the reduction in the personal UV exposure in tree shade over a year. The personal annual erythemal UV exposures in the tree shade ranged from 2,510 SED (Standard Erythema Dose) for the vertical part of...
Although excessive exposure to UV is widely recognized as a major factor leading to skin perturbations and cancer, the complex mechanisms underlying inflammatory skin disorders resulting from UV exposure remain incompletely characterized. The nuclear hormone receptor PPARb/d is known to control mouse cutaneous repair and UV-induced skin cancer development. Here, we describe a novel PPARb/d-depe...
The influence of unpolarized and linearly polarized UV exposure on previously rubbed as well untreated thin polyimide ͑PI͒ alignment layers was studied. Optical retardation and surface morphology measurements were carried out to understand the nature of surface modification as a function of the polarization and the exposure time of the UV light under different surface conditions. The exposure of ...
Apoptosis plays an important role in eliminating cells from populations when cells have been exposed to UV irradiation and damaged. Studies of cells in culture have provided some details of the mechanisms involved when stress response genes act after exposure to UV irradiation and other environmental stresses. However, little is known about the responses of intact sections of human skin growing...
IMPORTANCE Solar UV irradiation causes photoaging, characterized by fragmentation and reduced production of type I collagen fibrils that provide strength to skin. Exposure to UV-B irradiation (280-320 nm) causes these changes by inducing matrix metalloproteinase 1 and suppressing type I collagen synthesis. The role of UV-A irradiation (320-400 nm) in promoting similar molecular alterations is l...
FWT-60 radiochromic film has been tested for colouration effects from fluorescent light sources and shown to produce a marked colouration when exposed to office fluorescent light sources showing an approximate 1 OD unit per 0.5 J m(-2) exposure to a broad ultraviolet (UV) UVA + UVB spectrum at the peak absorption wavelength. This produces a measurable and quantifiable response to UV exposure. B...
Net photosynthesis, growth, and ultraviolet (UV) radiation absorbance were determined for the first leaf of Cucurbita pepo L. exposed to two levels of UV-B irradiation and a UV-B radiation-free control treatment. Absorbance by extracted flavonoid pigments and other UV-B radiation-absorbing compounds from the first leaves increased with time and level of UV-B radiation impinging on leaf surfaces...
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