Search results for "ULTRAVIOLET"
showing 10 items of 853 documents
Expression of the human XPB/ERCC-3 excision repair gene-homolog in the sponge Geodia cydonium after exposure to ultraviolet radiation.
1998
Abstract The marine demosponge Geodia cydonium encodes a gene, termed GCXPB , which displays 62% identity to the human XPB/ERCC-3 gene that specifically corrects the repair defect in xeroderma pigmentosum and in Cockayne's syndrome. The cDNA was isolated and characterized the deduced aa sequence, XPB_GEOCY, with the calculated size of 91,541 Da comprises the characteristic domains found in the related helicases. Phylogenetic tree analysis revealed that the sponge sequence is grouped to the metazoan related XPB/ERCC-3 polypeptides. Northern Blot analyses have been performed with sponge samples collected at different depths, thus exposed to different intensities of UV sunlight in the field. T…
Ultraviolet B Irradiation Affects Resistance of Rainbow Trout (Oncorhynchus mykiss) Against Bacterium Yersinia ruckeri and Trematode Diplostomum spat…
2007
Ultraviolet B (UVB) radiation is known to have various effects on the immune system of fish, but the effect on the actual disease resistance has remained largely unknown. Here we studied the effect of UVB on the resistance of rainbow trout (Oncorhynchus mykiss) against a bacterium Yersinia ruckeri, the causative agent of enteric red mouth disease, and a trematode parasite Diplostomum spathaceum, which causes cataracts in fish. The fish were exposed to UVB irradiation seven times in 14 days, and inoculated intraperitoneally with Y. ruckeri on day 5 after the first irradiation. On day 2 postinfection (p.i.), the number of viable bacteria in the kidney was lower in UVB-exposed than in unexpose…
OPTICAL PROPERTIES OF DEFECTS IN SILICA
2000
The optical properties of point defects are frequently the most important parameter in applications of glassy silica. They are relatively easy to measure on standard spectrophotometers and yield direct information on the quality of practical silica-based devices, e.g., attenuation of fiber-optic waveguides or ultraviolet (UV)- transmitting windows. However, optical measurements alone usually do not give enough information to establish the origin and atomic structure of the respective point defects.
γ-ray induced GeODC(II) centers in germanium doped α-quartz crystal
2011
International audience; Main luminescence of α-quartz crystal doped with germanium results from the luminescence of a self-trapped exciton (STE) near germanium. In as grown Ge-doped α-quartz crystal, the luminescence associated with the twofold coordinated Ge center (GeODC) in amorphous silica glass doped with germanium, was never observed. In this work, we performed experiments to investigate if a GeODC like luminescence could appear after a γ-irradiation of a Ge-doped α-quartz crystal. The answer is positive: under excitation with pulsed light of an ArF laser (193 nm): a new luminescence with two bands -- a blue one associated to a time constant of about 100 μs appears and another one wit…
Radiation-induced defects in fluorine-doped silica-based optical fibers: Influence of a pre-loading with H2
2009
International audience; We investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200–850 nm range of wavelengths (1.5–6 eV). We also studied the influence of pre-loading this kind of fibers with hydrogen on its radiation sensitivity. Our results showed that, for our experimental conditions (pre-treatment with H2 several months before irradiation with diffusion of all the H2 out the fiber core and cladding before X-ray exposure), this pre-treatment increases the radiation-induced attenuation in the ultraviolet part (200–300 nm) of the spectrum. A previous H2-loading has no influence at greater wavelengths. The nature of the radiati…
Effect of onion consumption by rats on hepatic drug-metabolizing enzymes
2001
Fruits and vegetables or their natural constituents which increase detoxication enzymes and/or reduce activating enzymes are considered as good candidates to prevent chemically-induced carcinogenesis. In this study, rats were fed a diet supplemented with 20% onion powder for 9 days. Several cytochrome P450 (CYP)s enzymes (CYP 1A, 2B, 2E1, 3A), which are involved in carcinogen activation, were determined by measuring their enzyme activities using specific substrates. In addition, phase II enzymes activities such as UDP-glucuronosyltransferase (UGT) and glutathione S-transferase (GST), involved in detoxication of carcinogens, were measured. Protein levels of CYPs and GST A1/A2, A3/A5, Ml, M2 …
Actinic cheilitis: Proposal of a clinical index.
2021
Actinic cheilitis is a potentially malignant lesion most commonly found in the lower lip of individuals with chronic exposure to ultraviolet radiation. The aim of this study was to develop and to test a clinical index that can be used to assess the severity of actinic cheilitis. The clinical index of actinic cheilitis was applied to 36 patients. An incisional biopsy was obtained to grade oral epithelial dysplasias following the World Health Organization (WHO) and binary systems, and to evaluate their association with clinical characteristics by Fisher?s exact test (P<0.05). The accuracy of the index was evaluated based on sensitivity, specificity, positive and negative predictive values, an…
Modelling the effect of nuclear motion on the attosecond time-resolved photoelectron spectra of ethylene
2014
arXiv:1403.5408
Do Tengmalm's owls see vole scent marks visible in ultraviolet light?
1997
Scent markings (urine and faeces) of small mammals are visible in ultraviolet (UV) light. Diurnal kestrels, Falco tinnunculususe them as a cue to find areas of food abundance. We studied whether vole-eating, nocturnal Tengmalm's owls, Aegolius funereuscan see vole scent marks using UV-vision. In a laboratory experiment, 14 young (less than 6 months old) and 14 adult (more than 6 months old) owls were individually given a choice between four adjacent arenas: (1) an arena with vole urine and faeces in UV light; (2) an arena with vole urine and faeces in visible light; (3) a clean arena in UV light; and (4) a clean arena in visible light. Owls did not prefer any of the four arenas. Our results…
UV reflecting vole scent marks attract a passerine, the great grey shrike Lanius excubitor
2002
Diurnal raptors have been shown to use ultraviolet vision and UV-reflecting vole scent marks to find suitable hunting areas. We studied if a passerine species, the great grey shrike Lanius excubitor that uses voles as its primary food, may also detect prey-patches in the same way. We conducted a laboratory experiment with ten shrikes. Each individual shrike had four options to choose from: (1) scent marks with UV light, (2) scent marks without UV light, (3) clean arena with UV light, and (4) clean arena without UV light. The birds preferred the scent-marked arena with UV light as measured by the number of scans and the time spent above it. Therefore, we suggest that great grey shrike probab…