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Ultraviolet
Kinds of Ultraviolet Terms modified by Ultraviolet Selected AbstractsThe Polyhydroxy Acid Gluconolactone Protects Against Ultraviolet Radiation in an In Vitro Model of Cutaneous PhotoagingDERMATOLOGIC SURGERY, Issue 2 2004Eric F. Bernstein MD Background. Ultraviolet (UV) radiation damages skin through a variety of mechanisms, including the generation of free radicals. Gluconolactone is a polyhydroxy acid (PHA) that is capable of chelating metals and may also function by scavenging free radicals, thereby protecting skin from some of the damaging effects of UV radiation. Objective. This study measured the ability of gluconolactone to protect against UV radiation,induced damage. Methods. The ability of gluconolactone to prevent UV radiation,induced elastin promoter activation was determined in vitro using a transgenic model of cutaneous photoaging. Gluconolactone was also evaluated to determine its ability to promote the formation of sunburn cells in human skin after exposure to UV radiation. Results. Gluconolactone provided up to 50% protection against UV radiation, as measured in our in vitro system, and did not significantly increase sunburn cells in human skin. Conclusions. These results demonstrate the ability of the PHA gluconolactone to protect against UV radiation,induced elastin promoter activation. In addition, in vivo studies demonstrated that gluconolactone treatment does not result in a significant increase in sunburn cells. Further investigation of this and other PHAs is necessary to identify their potential role in preventing and repairing cutaneous photodamage. [source] "Ultraviolet spring" and the ecological consequences of catastrophic impactsECOLOGY LETTERS, Issue 2 2000Charles S. Cockell Asteroid and comet impacts cause ozone depletion. For the first time, we have quantified the photobiological characteristics of these events and speculate on some of the associated ecological consequences. Following the clearing of stratospheric dust after "impact winter", levels of damaging UVB radiation (280,315 nm) could increase by at least 100%, resulting in an "ultraviolet spring". Many of the taxa stressed by the cold and dark conditions of impact are the same that would be stressed by large increases in UVB radiation. Furthermore, depletion of dissolved organic carbon (DOC) by impact-induced acid rain would increase UVB penetrability into freshwater systems. Although an increase in UVB radiation is an attractive hypothesis for exacerbating the demise of land animals at the Cretaceous-Tertiary (K/T) boundary, e.g. dinosaurs, our calculations suggest the impact into rare sulphate-rich target rock may have prevented an ultraviolet spring in this case. If the K/T impact event had occurred in any other region on Earth, the stress to the biosphere would probably have been considerably greater. [source] Synthesis and characterization of metal sulfide clusters for toxicological studiesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2002Karl C. Bowles Abstract Zinc sulfide clusters were synthesized and characterized at low micromolar concentrations to assess the effect of metal-sulfide ligands on metal toxicity to aquatic organisms in oxic environments. Recommended preparation times are greater than 2 h initial reaction of equimolar sodium sulfide and zinc nitrate, followed by oxic aeration for 3 d. Ionic strength, pH, and anoxic stabilization time were found to be relatively unimportant in controlling the final yield. Adsorptive losses of zinc sulfide (ZnS) clusters to surfaces, however, were significant for a variety of vessel materials and membrane filters. Ionic strength and pH were found to be important factors controlling the extent of adsorptive losses with minimal loss for pHs greater than 9 and for soft waters. The Ag(I), Cu(II), and Hg(II) as metal sulfides completely suppress the analysis of sulfide, whereas Pb(II), Mn(II), and Co(II) partially suppress the analysis of sulfide by the methylene blue technique. Ultraviolet and fluorescence spectra are shown for synthesized ZnS clusters. [source] Effects of Ultraviolet Radiation on Locomotion and Orientation in Roughskin Newts (Taricha granulosa)ETHOLOGY, Issue 3 2000Andrew R. Blaustein Environmental changes, including those associated with the atmosphere may significantly affect individual animals and ultimately populations. Ultraviolet (UV) radiation, perhaps increasing due to stratospheric ozone depletion, has been linked to mortality in a number of organisms, including amphibians. The eggs and larvae of certain amphibian species hatch at significantly lower rates when exposed to ambient ultraviolet light. Yet little is known about the sublethal effects of UV radiation. For example, UV radiation may affect specific behaviors of an animal that could alter its ability to survive. To examine if UV radiation affects amphibian behavior, we used roughskin newts (Taricha granulosa) as a model. Newts were exposed to low-level doses of UV in the laboratory and then tested in the field to examine if UV-exposed and control (no UV) newts differed in orientation towards water or in locomotor activity levels. UV-exposed and control newts both exhibited a significant orientation towards water in field tests but there was no significant difference in orientation between treatments. However, UV-exposed newts were significantly more active than control newts. Our results suggest that exposure to short-term low levels of UV radiation alters certain behaviors. Environmentally induced changes in behavior may have significant ecological and evolutionary consequences. [source] Green tea extract reduces induction of p53 and apoptosis in UVB-irradiated human skin independent of transcriptional controlsEXPERIMENTAL DERMATOLOGY, Issue 1 2009Christian D. Mnich Abstract:, Ultraviolet (UV) irradiation plays a pivotal role in human skin carcinongenesis. Preclinically, systemically and topically applied green tea extract (GTE) has shown reduction of UV-induced (i) erythema, (ii) DNA damage, (iii) formation of radical oxygen species and (iv) downregulation of numerous factors related to apoptosis, inflammation, differentiation and carcinogenesis. In humans, topical GTE has so far only been tested in limited studies, with usually very high GTE concentrations and over short periods of time. Both chemical stability of GTE and staining properties of highly concentrated green tea polyphenols limit the usability of highly concentrated green tea extracts in cosmetic products. The present study tested the utility of stabilized low-dose GTE as photochemopreventive agents under everyday conditions. We irradiated with up to 100 mJ/cm2 of UVB light skin patches which were pretreated with either OM24® -containing lotion or a placebo lotion. Biopsies were taken from both irradiated and un-irradiated skin for both immunohistochemistry and DNA microarray analysis. We found that while OM24® treatment did not significantly affect UV-induced erythema and thymidine dimer formation, OM24® treatment significantly reduced UV-induced p53 expression in keratinocytes. We also found that OM24® treatment significantly reduced the number of apoptotic keratinocytes (sunburn cells and TUNEL-positive cells). Carefully controlled DNA microarray analyses showed that OM24® treatment does not induce off-target changes in gene expression, reducing the likelihood of unwanted side-effects. Topical GTE (OM24®) reduces UVB-mediated epithelial damage already at low, cosmetically usable concentrations, without tachyphylaxis over 5 weeks, suggesting GTE as suitable everyday photochemopreventive agents. [source] Production and clearance of cyclobutane dipyrimidine dimers in UV-irradiated skin pretreated with 1% pimecrolimus or 0.1% triamcinolone acetonide creams in normal and atopic patientsEXPERIMENTAL DERMATOLOGY, Issue 5 2006Laurence Doelker Background:, Ultraviolet (UV)-induced pyrimidine dimers are an early step in skin carcinogenesis, which is accelerated in the setting of long-term immunosuppression with systemic calcineurin inhibitors. It is not known whether topical application of calcineurin inhibitors exposes to a similar risk. Objective:, To assess the formation and clearance of UV-induced dipyrimidine dimers in human epidermis treated with topical pimecrolimus as compared to topical steroid, vehicle and untreated control. Methods:, Pretreated buttock skin of 20 human volunteers with (10) or without (10) atopic dermatitis was exposed to two minimal erythema doses (MED) of simulated solar radiation. DNA was extracted from epidermis 1 and 24 h postirradiation. Pyrimidine dimers were visualized by immuno slot blots and quantified by chemoluminescence image analysis. Results:, One-hour postirradiation, pimecrolimus-treated epidermis contains less DNA damage as compared to untreated control, but there were no statistically significant differences between pimecrolimus, triamcinolone acetonide and vehicle. Dimer levels at 24 h postirradiation showed no significant differences between different treatments. Conclusion:, Treatment with pimecrolimus cream, triamcinolone acetonide cream and vehicle is not associated with increased epidermal DNA damage at 1 and 24 h post-UV exposure. [source] Surface Plasmonics: Plasmonic Crystals: A Platform to Catalog Resonances from Ultraviolet to Near-Infrared Wavelengths in a Plasmonic Library (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Mater. Research in the field of surface plasmonics is finding application in many areas; for example, in data storage, nano-electronics, and biosensing. In their feature article on page 529, H. Gao et al. describe recent progress in manipulating surface plasmons from the ultraviolet to near-infrared wavelengths using nanostructured plasmonic crystals (shown in the cover image), and build a comprehensive library of plasmonic resonances, bringing together for the first time the resonance characteristics of key plasmonic materials. [source] Plasmonic Crystals: A Platform to Catalog Resonances from Ultraviolet to Near-Infrared Wavelengths in a Plasmonic LibraryADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Hanwei Gao Abstract Surface plasmons are responsible for a variety of phenomena, including nanoscale optical focusing, negative refraction, and surface-enhanced Raman scattering. Their characteristic evanescent electromagnetic fields offer opportunities for sub-diffraction imaging, optical cloaking, and label-free molecular sensing. The selection of materials for such applications, however, has been traditionally limited to the noble metals Au and Ag because there has been no side-by-side comparison of other materials. This feature article describes recent progress on manipulating surface plasmons from ultraviolet to near-infrared wavelengths using plasmonic crystals made from 2D nanopyramidal arrays. A library of plasmon resonances is constructed in the form of dispersion diagrams for a series of unconventional and new composite plasmonic materials. These resonances are tuned by controlling both intrinsic factors (unit cell shape, materials type) and extrinsic factors (excitation conditions, dielectric environment). Finally, plasmonic crystals with reduced lattice symmetries are fabricated as another means to tailor resonances for broadband coupling. [source] Protective effects of a topical antioxidant mixture containing vitamin C, ferulic acid, and phloretin against ultraviolet-induced photodamage in human skinJOURNAL OF COSMETIC DERMATOLOGY, Issue 4 2008Christian Oresajo PhD Summary Background, Ultraviolet (UV) irradiation of the skin leads to acute inflammatory reactions, such as erythema, sunburn, and chronic reactions, including premature skin aging and skin cancer. Aim, In this study, the effects of a topical antioxidant mixture consisting of vitamin C, ferulic acid, and phloretin on attenuating the harmful effects of UV irradiation on normal healthy volunteers were studied using biomarkers of skin damage. Subjects/methods, Ten subjects (age, 18,60 years; Fitzpatrick skin types II and III) were randomized and treated with antioxidant product or vehicle control on the lower back for four consecutive days. On day 3, the minimal erythema dose (MED) was determined for each subject at a different site on the back. On day 4, the two test sites received solar-simulated UV irradiation 1,5× MED at 1× MED intervals. On day 5, digital images were taken, and 4-mm punch biopsies were collected from the two 5× MED test sites and a control site from each subject for morphology and immunohistochemical studies. Results, UV irradiation significantly increased the erythema of human skin in a linear manner from 1× to 5× MED. As early as 24 h after exposure to 5× MEDs of UV irradiation, there were significant increases in sunburn cell formation, thymine dimer formation, matrix metalloproteinase-9 expression, and p53 protein expression. All these changes were attenuated by the antioxidant composition. UV irradiation also suppressed the amount of CD1a-expressing Langerhans cells, indicating immunosuppressive effects of a single 5× MED dose of UV irradiation. Pretreatment of skin with the antioxidant composition blocked this effect. Conclusion, This study confirms the protective role of a unique mixture of antioxidants containing vitamin C, ferulic acid, and phloretin on human skin from the harmful effects of UV irradiation. Phloretin, in addition to being a potent antioxidant, may stabilize and increase the skin availability of topically applied vitamin C and ferulic acid. We propose that antioxidant mixture will complement and synergize with sunscreens in providing photoprotection for human skin. [source] Immune protective effect of a moisturizer with DNA repair ingredientsJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2008Cheré R Lucas MD Summary Ultraviolet (UV) light damages DNA and impairs immune surveillance. The faulty repair of DNA after UV exposure is associated with immune suppression and facilitates photodamage that leads to photoaged skin and the growth of skin cancer. Sunscreens have been developed to filter UV light from entering the skin, but are not beneficial once DNA damage has occurred. Enhancing DNA repair after UV radiation may provide added advantage and prevent UV immunosuppression. This study was performed to determine whether a product with DNA repair ingredients prevents UV-induced suppression of contact hypersensitivity responses in vivo. Solar simulated radiation was delivered on skin with and without topical treatment with a moisturizer containing DNA repair enzymes (Advanced Night Repair Concentrate). Subjects were then sensitized to the hapten dinitrochlorobenzene, and the level of resultant contact hypersensitivity response was elicited 2 weeks later. Contact hypersensitivity response measured by skin fold thickness was significantly suppressed in untreated UV-irradiated subjects but not in subjects treated with DNA repair moisturizer after solar simulated radiation. Our results indicate that DNA repair ingredients significantly prevent UV-induced immune suppression. [source] Modulations of nerve growth factor and Bcl-2 in ultraviolet-irradiated human epidermisJOURNAL OF CUTANEOUS PATHOLOGY, Issue 6 2003Catherine M. Stefanato Background:, Ultraviolet (UV) irradiation to the skin causes apoptosis of keratinocytes. Melanocytes are more resistant to UV-induced apoptosis, due, in part, to high levels of antiapoptotic proteins such as Bcl-2. In vitro studies have shown that nerve growth factor (NGF), a neurotrophic polypeptide, is produced by keratinocytes and exerts a protective role for melanocytes by upregulating Bcl-2. The purpose of this study was to determine NGF and Bcl-2 modulations in UV-irradiated human skin. Methods:, Nine volunteers were irradiated with two minimal erythema doses using solar-simulated UV irradiation. Seventy-two hours post irradiation, skin biopsies were obtained from irradiated and sun-protected skin. The skin specimens were stained with anti-tyrosinase-related protein-1 monoclonal antibody IgG2a (Mel-5), anti-Bcl-2 (monoclonal antibody IgG-kappa), and with anti-NGF (polyclonal antibody IgG). Results:, NGF staining was identified within the cytoplasm of epidermal melanocytes, similar to the staining observed for TRP-1 and Bcl-2. While no significant difference in the number of TRP-1- and Bcl-2-positive melanocytes was observed between irradiated and non-irradiated skin within 72 h, the number of NGF-positive melanocytes decreased significantly, 72 h after UV irradiation (p < 0.024). NGF was also identified within keratinocytes, and while non-irradiated skin exhibited cytoplasmic NGF staining throughout the epidermis, NGF staining was reduced in the lower epidermal layers after UV irradiation. Conclusions:, This is the first in vivo study showing NGF to be present in melanocytes, as well as showing modulations of NGF and Bcl-2 in melanocytes, following solar-simulated UV irradiation. [source] Hydrodynamic Cavitation to Improve Bulk Fluid to Surface Mass Transfer in a Nonimmersed Ultraviolet System for Minimal Processing of Opaque and Transparent Fluid FoodsJOURNAL OF FOOD SCIENCE, Issue 9 2007P.J. Milly ABSTRACT:, Ultraviolet (UV)-induced chemical reactions and inactivation of microorganisms in transparent and opaque fluids are strongly dependent upon the homogenous exposure of the target species to the UV irradiation. Current UV technologies used in water disinfection and food preservation applications have limited efficacy due to suspended particles shading target species. An Ultraviolet-Shockwave PowerÔ Reactor (UV-SPR) consisting of an inner rotating rotor and a stationary quartz housing and 2 end plates was used to induce ,controlled cavitation.' Eight UV low-pressure mercury lamps spaced uniformly were installed lengthwise around the quartz housing periphery. A KI to I3,chemical dosimeter for UV was used to quantify photons received by fluid in the annular space of the SPR. UV dose (J/m2) increased from 97 J/m2 at 0 rpm to over 700 J/m2 for SPR speeds above 2400 rpm. Inactivation of E. coli 25922 in apple juice and skim milk in the UV-SPR at exit temperatures below 45 °C was greater than 4.5 and 3 logs, respectively. The UV-SPR system proved successful in increasing the mass transfer of transparent and opaque fluid to the UV irradiated surface. [source] An experimental test of a visual-based push,pull strategy for control of wood boring phytosanitary pestsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009Stephen Mark Pawson Abstract 1,International phytosanitary standards require mandatory fumigation for key wood boring beetle pests prior to export. Pressure to reduce the use of toxic fumigants has created a need for alternative control techniques. 2,A visual based push,pull strategy that exploits a differential attraction to yellow and ultra violet (UV) lights was tested for its efficacy at controlling Cerambycidae. 3,The relative attraction of four ,push' lighting treatments [two yellow (high and low-pressure Sodium), one white (metal halide) and a control (no light)] to beetles was assessed. Highly attractive UV ,pull' traps were compared with a paired control trap, the difference used as a measure of the UV traps attractiveness to residual beetles attracted by ,push' lights. 4,Trap catch beneath the two yellow ,push' lights was more similar to the control (no light) treatment than the white light for both species. Control ,push' lights had the highest average catch of Arhopalus ferus, whereas white light was least attractive. This finding was counter intuitive to expectations, and potential mechanisms are discussed. The white ,push' light was most attractive to Prionoplus reticularis. 5,Ultraviolet ,pull' traps were highly attractive to residual beetles drawn to yellow ,push' light treatments. Relative attraction to the UV ,pull' traps beneath control and white ,push' lights differed between species. 6,The results obtained suggest that a push,pull strategy combining yellow site lighting with UV kill traps could provide site specific control of wood borers. Future research should attempt large-scale trials that are subject to competing alternative stimuli at a wood processing site. [source] 1,5-Diphenyl-1,4-diyn-3-one: A highly efficient photoinitiatorJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2005Robert Liska Abstract In a continuation of our research on new chromophores for photoinitiators (PIs), we investigated a triple-bond-containing benzophenone derivative. 1,5-Diphenyl-1,4-pentadiyn-3-one (2) was prepared from phenylacetylene and ethyl formate by a one-pot reaction. Differential scanning photocalorimetry experiments in lauryl acrylate of 2 showed surprisingly high activity for the double-bond conversion and rate of polymerization at the lowest PI concentrations and even without any coinitiator. By the application of monomers with abstractable hydrogens, significant improvement in the photoreactivity was observed. Ultraviolet,visible spectroscopy revealed strong absorption up to 350 nm. Steady-state photolysis experiments proved that the photochemistry of this compound was faster than that of benzophenone. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 101,111, 2005 [source] Ultraviolet and visible Raman spectroscopic investigations of nanocrystalline carbon thin films grown by bias-assisted hot-filament chemical vapor depositionJOURNAL OF RAMAN SPECTROSCOPY, Issue 3 2003S. Gupta Abstract The structural bonding in a series of nanocrystalline carbon thin films grown under different substrate biasing conditions was analyzed using Raman spectroscopy in both the visible and ultraviolet (uv) regimes of the spectrum. The nanocrystalline carbon thin films studied were deposited by the hot-filament chemical vapor deposition (HFCVD) technique using a 2% concentration of methane in hydrogen. The films were deposited on molybdenum substrates under various substrate biasing conditions. A positive bias (forward) produced a continuous flow of electrons from the filament on to the substrate, whereas a negative bias (negative) caused the substrate to be bombarded with positive ions. Films were also grown under no bias, for comparison. Differences in the Raman spectra obtained with visible (,L = 514.5 nm) and uv (,L = 244.0 nm) excitation sources were investigated. Apart from the basic features consisting of D and G bands at around 1360 and 1580 cm,1 in the case of visible Raman spectra, an extra feature at around 1060 cm,1, denoted a T band, appeared in the uv Raman spectra only. Hence, uv Raman scattering measurements clearly revealed the presence of sp3 -bonded carbon atoms. The position and its intensity ratio with respect to the G peak [(I(T)/I(G)] were used to provide a reliable means to measure the sp3 C bonding fraction, which is both semi-quantitative and non-destructive. The sp3 content estimated within the microstructure of n-C thin films was found to be around 60,80%. Further, probing the samples with two different photons (visible and uv) allowed us to estimate qualitatively the amount and clustering of sp2 sites. This technique provided a fast and reliable microstructural characterization of disordered carbons. The dispersion in the Raman features is specific to each carbon system and, therefore, can be used as a fingerprint. These findings point at the similarities of bias-assisted HFCVD nanocrystalline carbon (n-C) materials and the tetrahedrally bonded amorphous carbon (ta -C) materials grown by ion-beam assisted deposition (IBAD). Copyright © 2003 John Wiley & Sons, Ltd. [source] Ultraviolet and visible emission cross-sections for Tm3+ : YLiF4 laser systemLASER PHYSICS LETTERS, Issue 2 2004T.D. Medoidze Abstract We present the measured values of emission cross sections for 1I6 manifold of Tm3+ embedded in YLiF4. For these measurements the original experimental equipment for laserexited fluorescence spectroscopy is used. The outcomes have potential applications to ultraviolet and visible, including tunable lasing based on 4f , 4f intra-configurational transitions in Tm3+ : YLiF4 systems. (© 2004 by HMS Consultants. Inc. Published exclusively by WILEY-VCH Verlag GmbH & Co.KGaA) [source] A Wide-Bandgap Semiconducting Polymer for Ultraviolet and Blue Light Emitting Diodes,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 18 2003Ping Lu Abstract A novel wide-bandgap conjugated polymer (PDHFSCHD) consisting of alternating dihexylfluorene and rigidly twisted biphenyl units has been synthesized. The new fluorene-based copolymer composed of rigid twisting segments in the main-chain exhibits an optical bandgap of as high as 3.26 eV, and a highly efficient ultraviolet emission with peaks at 368 nm and 386 nm. An electroluminescence device from PDHFSCHD neat film as an active layer shows UV emission which peaks at 395 nm with a turn on voltage below 8 V. By optimizing the device conditions, a peak EL quantum efficiency of 0.054% and brightness of 10 cd,·,m,2 was obtained. Furthermore, blending a poly(dihexylfluorene) in the PDHFSCHD host gave pure blue emission peaking at 417 nm and 440 nm without long wavelength emission from aggregated species. Efficient energy transfer from PDHFSCHD to PDHF was demonstrated in these blended systems. Depressed chain-aggregation of PDHF in the PDHFSCHD host can correspond to pure blue emission behaviors. The structure of the copolymer PDHFSCHD. [source] Protective effect of vitamin E on ultraviolet B light,induced damage in keratinocytesMOLECULAR CARCINOGENESIS, Issue 3 2002Samar Maalouf Abstract Ultraviolet (UV) B radiation is the most common environmental factor in the pathogenesis of skin cancer. Exposure of human skin to UVB radiation leads to the depletion of cutaneous antioxidants, the activation of nuclear factor kappa B (NF-,B), and programmed cell death (apoptosis). Although antioxidant supplementation has been shown to prevent UVB-induced photooxidative damage, its effect on components of cell signaling pathways leading to gene expression has not been clearly established. In the present study, the effect of the antioxidant vitamin, ,-tocopherol (,-T), and its acetate analog, ,-tocopherol acetate (,-TAc), on UVB-induced damage in primary and neoplastic mouse keratinocytes was investigated. The ability of both vitamins to modulate UVB-induced apoptosis and activation of the transcription factor NF-,B were studied. Treatment of normal and neoplastic mouse epidermal keratinocytes (308 cells) with 30,60 mJ/cm2 UVB markedly decreased viable cell number and was accompanied by DNA fragmentation. When both vitamins were applied to cells at times before and after UVB radiation, a significant increase in the percentage of viable cells and concomitant decrease in the number of apoptotic cells was noted, with vitamin pretreatment providing a better protection than posttreatment. Simultaneous posttreatment of irradiated cells with ,-TAc abolished the cytotoxic effects of UVB and restored cell viability to control levels. In addition, simultaneous posttreatment of irradiated cells with ,-T reduced the number of apoptotic cells by half, indicating a synergistic effect of two such treatments compared with any single one. Flow cytometry analysis indicated that vitamin treatment suppressed both an increase in pre-G0 cells and a decrease in cycling cells by UVB exposure. In addition, NF-,B activation was detected 2 h after UV exposure and was maintained for up to 8 h. Pretreatment with vitamins significantly inhibited NF-,B activation at 4 and 8 h. These results indicate that vitamin E and its acetate analog can modulate the cellular response to UVB partly through their action on NF-,B activation. Thus, these antioxidant vitamins are potential drugs for the protection from or the reduction of UVB-associated epidermal damage. © 2002 Wiley-Liss, Inc. [source] Selection of ThAr lines for wavelength calibration of echelle spectra and implications for variations in the fine-structure constantMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2007M. T. Murphy ABSTRACT Echelle spectrographs currently provide some of the most precise and detailed spectra in astronomy, the interpretation of which sometimes depends on the wavelength calibration accuracy. In some applications, such as constraining cosmological variations in the fundamental constants from quasar absorption lines, the wavelength calibration is crucial. Here we detail an algorithm for selecting thorium,argon (ThAr) emission lines for wavelength calibration which incorporates the properties of both a new laboratory wavelength list and the spectrograph of interest. We apply the algorithm to the Very Large Telescope Ultraviolet and Visual Echelle Spectrograph (UVES) and demonstrate a factor of ,3 improvement in the wavelength calibration residuals (i.e. random errors) alone. It is also found that UVES spectra calibrated using a previous, widely distributed line-list contain systematic ±30 ,75 m s,1 distortions of the wavelength scale over both short and long wavelength ranges. These distortions have important implications for current UVES constraints on cosmological variations in the fine-structure constant. The induced systematic errors are most severe for Mg/Feii quasar absorbers in the redshift range 1.2 ,zabs, 2.3, with individual absorbers studied by recent authors containing systematic errors up to four times larger than quoted statistical errors. [source] Early-type stars observed in the ESO UVES Paranal Observatory Project , I. Interstellar Na i UV, Ti ii and Ca ii K observations,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006I. Hunter ABSTRACT We present an analysis of interstellar Na i (,air= 3302.37 and 3302.98 Å), Ti ii(,air= 3383.76 Å) and Ca ii K (,air= 3933.66 Å) absorption features for 74 sightlines towards O- and B-type stars in the Galactic disc. The data were obtained from the Ultraviolet and Visual Echelle Spectrograph Paranal Observatory Project, at a spectral resolution of 3.75 km s,1 and with mean signal-to-noise ratios per pixel of 260, 300 and 430 for the Na i, Ti ii and Ca ii observations, respectively. Interstellar features were detected in all but one of the Ti ii sightlines and all of the Ca ii sightlines. The dependence of the column density of these three species with distance, height relative to the Galactic plane, H i column density, reddening and depletion relative to the solar abundance has been investigated. We also examine the accuracy of using the Na i column density as an indicator of that for H i. In general, we find similar strong correlations for both Ti and Ca, and weaker correlations for Na. Our results confirm the general belief that Ti and Ca occur in the same regions of the interstellar medium (ISM) and also that the Ti ii/Ca ii ratio is constant over all parameters. We hence conclude that the absorption properties of Ti and Ca are essentially constant under the general ISM conditions of the Galactic disc. [source] Optimization of DNA Extraction from a Scleractinian Coral for the Detection of Thymine Dimers by Immunoassay,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Anastazia T. Banaszak ABSTRACT Ultraviolet (UV)-B is known to cause DNA damage, principally by the formation of thymine dimers, but little research has been conducted in coral reef environments where UV doses are high. The majority of tropical reef-dwelling corals form a mutualistic symbiosis with the dinoflagellate Symbiodinium but few studies have been conducted on in situ DNA damage in corals and none have investigated the symbiotic components separately. The aim of this research was to quantify DNA damage in both the coral host and the dinoflagellate symbiont. The first step in this investigation was to optimize the extraction of DNA from the host, Porites astreoides, as well as the symbiont. The optimization was divided into a series of steps: the preservation of the samples, separation of the coral tissue from the skeleton, separation of the host tissue from the algal cells to prevent cross contamination as well as the extraction and purification of genomic DNA from the algae that are located intracellularly within the invertebrate animal tissue. The best preservation method was freezing at low temperatures without ethanol. After scraping with a razor blade, the coral tissue can be divided into host and algal components and the DNA extracted using modifications of published techniques yielding DNA suitable for the quantification of thymine dimer formation using antibodies. Preliminary data suggest that in P. astreoides collected from 1 m depth, thymine dimers form approximately 2.8 times more frequently in the host DNA than in the DNA of its symbionts. [source] Impairment of Eye Lens Cell Physiology and Optics by Broadband Ultraviolet A,Ultraviolet B Radiation,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2002O. M. Oriowo ABSTRACT The phototoxicity of ultraviolet A (UVA) alone and UVA plus ultraviolet B (UVB) combined on cultured porcine lenses was investigated by analyzing cellular function as measured with a fluorescence bioassay approach and optical integrity, in terms of sharpness of the lens focus as measured with a scanning laser system. The bioassay consisted of carboxyfluorescein diacetate-acetoxymethyl ester and alamarBlue fluorescent dyes. Aseptically dissected porcine lenses were maintained in modified medium 199 without phenol red supplemented with 1% penicillin,streptomycin and 4% porcine serum. At 1 week of preincubation, baseline measurements were obtained. Then the lenses were treated with single exposures of different UVA and UVB energy levels. The lenses treated with 86 J/cm2 UVA alone showed a significant (P < 0.05) decrease in cellular and optical integrity at 48 h after exposure, whereas those treated with 43 J/cm2 UVA alone did not show significant phototoxic effect. Lenses treated with 15.63 J/cm2 UVA plus 0.019 J/cm2 UVB combined showed significant adverse effects beginning from 48 h after exposure. Also, there was no recovery. These findings show that a high UVA dose alone and relatively low UVA in combination with low UVB radiant exposure can impair lens cellular and optical functions, respectively. [source] Phototherapy in the management of atopic dermatitis: a systematic reviewPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2007N. Bhavani Meduri Background/purpose: Atopic dermatitis (AD) is a common and extremely burdensome skin disorder with limited therapeutic options. Ultraviolet (UV) phototherapy is a well tolerated, efficacious treatment for AD, but its use is limited by a lack of guidelines in the optimal choice of modality and dosing. Given this deficit, we aim to develop suggestions for the treatment of AD with phototherapy by systematically reviewing the current medical literature. Methods: Data sources: All data sources were identified through searches of MEDLINE via the Ovid interface, the Cochrane Central Register of Controlled Trials, and a complementary manual literature search. Study selection: Studies selected for review met these inclusion criteria, as applied by multiple reviewers: controlled clinical trials of UV phototherapy in the management of AD in human subjects as reported in the English-language literature. Studies limited to hand dermatitis and studies in which subjects were allowed unmonitored use of topical corticosteroids or immunomodulators were excluded. Data extraction: Included studies were assessed by multiple independent observers who extracted and compiled the following data: number of patients, duration of treatment, cumulative doses of UV radiation, adverse effects, and study results. Data quality was assessed by comparing data sets and rechecking source materials if a discrepancy occurred. Results: Nine trials that met the inclusion criteria were identified. Three studies demonstrated that UVA1 is both faster and more efficacious than combined UVAB for treating acute AD. Two trials disclosed the advantages of medium dose (50 J/cm2) UVA1 for treating acute AD. Two trials revealed the superiority of combined UVAB in the management of chronic AD. Two additional studies demonstrated that narrow-band UVB is more effective than either broad-band UVA or UVA1 for managing chronic AD. Conclusion: On the basis of available evidence, the following suggestions can be made: phototherapy with medium-dose (50 J/cm2) UVA1, if available, should be used to control acute flares of AD while UVB modalities, specifically narrow-band UVB, should be used for the management of chronic AD. [source] Comparison of broadband UVB, narrowband UVB, broadband UVA and UVA1 on activation of apoptotic pathways in human peripheral blood mononuclear cellsPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 1 2007Chanisada Tuchinda Background/purpose: Ultraviolet (UV) radiation is an important therapy for immune-mediated cutaneous diseases. Activation of early apoptotic pathways may play a role in the clinical effectiveness. Different UV wavelengths have different efficacy for various diseases, but it remains unclear whether the ability to induce apoptosis differs with respect to the wavelength, and whether they induce apoptosis through the same mechanism. The aim of this study is to analyze the effects of different UV wavelengths that are used clinically on normal human peripheral blood mononuclear cells (PBMCs). Methods: PBMCs were treated with UV-light sources broadband UVB, narrowband UVB, broadband UVA and UVA1. Initiation of apoptosis was assessed by flow cytometry by staining,treated cells for activated caspases. Immunoblots were performed to measure for cleaved caspase-3, -8, -9, cytochrome c, Bcl 2-interacting domain and poly-(ADP ribose) polymerase cleavage. Results: We demonstrate that all the UV radiation sources induced caspase activation in a dose-and time-dependent manner. Components of both the extrinsic and intrinsic pathways of apoptosis were activated by all of the UV wavelengths tested, but differed in the level of energy needed for activation. Conclusion: The greater effectiveness of UVB on initiation of apoptotic pathway suggests that apoptosis may play a role in the clinical efficacy of UVB-responsive inflammatory cutaneous diseases. [source] Cloning and identification of EDD gene from ultraviolet-irradiated HaCaT cellsPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 6 2006Nishma Gupta Ultraviolet (UV) radiation is one of the most important external stimuli that affects skin by inducing cancer, inflammation and cell death. To identify the regulation of genes regulated by UV during transformation, normal human keratinocyte cell line, HaCaT, was exposed to multiple doses of UVA+B (UVA , 150,200 mJ/cm2 and UVB , 15,20 mJ/cm2× 6). Malignant transformation was confirmed by formation of colonies on soft agar and DNA methylation assay. To identify the genes involved in this process, random amplification of polymorphic DNA using RNA from unexposed and multiple exposed cells was performed after each exposure. A few up-regulated genes were identified, cloned and sequenced. One of the genes had homology to EDD (E3 identified by differential display) that was up-regulated at second exposure but was down-regulated in colony-forming cells (cells that received six or more exposures) as determined by RT-PCR. This is a progesterone-induced gene and progesterone treatment reduced the extent of colony formation on soft agar plate. It is possible that hormone therapy may have some effects on skin cancer in vivo. [source] Ultraviolet A in vitiligoPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2006Medhat El-Mofty Both types of Ultraviolet (UV), UVB (290,320 nm) and UVA (320,400 nm), produce increased pigmentation or tanning. However, no evaluation of UVA alone in the treatment of vitiligo has been reported. Therefore, it was the purpose of this work to study the pigmentogenic effect of UVA (5 and 15 J/cm2) in vitiligo. The study included 20 randomly selected patients with vitiligo involving more than 30% of the body surface area with a bilateral/symmetrical distribution. They were equally divided into two groups each of 10 patients. All patients received three weekly sessions of UVA, 15 J/cm2 in group I and 5 J/cm2 in group II, a total of 48 sessions over 16 weeks. Overall pigmentation of 60% and above was recorded in 50% and 10% of patients in groups I and II, respectively. We conclude that broadband UVA alone, without psoralens, and in appropriate doses may be of important therapeutic value in vitiligo. [source] Ultraviolet A exposure might increase metastasis of mouse melanoma: a pilot studyPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2005Riikka Pastila Background: The major sources of long-wave ultraviolet A radiation (UVA; 320,400 nm) exposure are extensive sunbathing and tanning in solaria. While the carcinogenic effects of mid-wave ultraviolet B radiation (UVB; 280,320 nm) are well recognized, the potentially hazardous effects of UVA are less understood. Several studies have shown that a variety of physiological processes in the cell are modified by UVA exposure, some of which might be involved in the regulation of tumor metastasis. In this study we suggest that UVA radiation could lead to the increase of metastatic capability of melanoma cells in mice. Method/result: A pilot in vivo study was executed using C57BL/6 mice and syngeneic B16 melanoma cell lines. Mice were intravenously (i.v.) injected with either B16-F1 or B16-F10 melanoma cells into the tail vein and then immediately exposed to UVA. Fourteen days after melanoma injection, lungs were collected and the quantity and quality of metastases were determined under a dissecting microscope. As an outcome of the pilot study we observed that i.v. injected melanoma cells formed more lung metastases in the UVA-exposed mice in comparison with the control mice. Conclusion: This result suggests that the UVA exposure of mice, with melanoma cells present in blood circulation, increases the formation of melanoma metastases in lungs. Further studies should determine whether a similar pro-metastatic effect, as observed in mice, could occur in humans and whether other than melanoma tumors might be susceptible. [source] Phototoxicity of exogenous protoporphyrin IX and ,-aminolevulinic acid in the photo hen's egg testPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 5 2004Norbert J. Neumann Background: Oxygen, appropriate light sources, and special photosensitizers are necessary to induce photochemical damage in tumor cells via photodynamic therapy (PDT) ,-aminolevulinic acid (ALA) is increasingly used in PDT, because topical or systemic administration of ALA induces accumulation of endogenous porphyrins preferentially in neoplastic tissues. Subsequent radiation with light of approximately 630 nm leads to selective damage of tumor cells. PDT should optimally leave peritumoral tissues unaffected, but only few data are reported on the effects and the time course of ALA-induced porphyrins in tumor-free tissues. Methods: Therefore, we studied the phototoxic effects of protoporphyrin IX (PP) and ALA-induced porphyrins in a recently established photototoxic model based on tumor-free tissue, the photo hen's egg test (PHET). Results: Employing this test procedure, PP provoked strong phototoxic reactions when irradiated with Ultraviolet A immediately and up to 30 h after substance application. In contrast, ALA induced a significant phototoxic effect only if irradiated 24 h after application. Conclusion: Thus, we observed a delayed phototoxic effect of ALA in tumor-free tissue of the yolk sac (YS) blood vessel system. This delayed phototoxic response 24 h after ALA application is probably caused by endogenously synthesized porphyrins. In contrast, epithelial tumors show a maximum porphyrin accumulation 4,8 h after ALA application whereas in healthy human skin porphyrin synthesis is less intensive but prolonged with maximum levels 24,48 h after ALA application. Thus, ALA induced virtually the same delayed phototoxic effect in the tumor-free YS blood vessel tissue as in healthy human skin. These results show that the PHET is a useful model for the predictive preclinical risk assessment of exogenous or endogenous photosensitizers. [source] Whole-body UVB (TL-01) or UVA-1 irradiation does not alter the levels of immunomodulatory cytokines in the serum of human volunteersPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2004P. Mcloone Background/Purpose: Ultraviolet (UV) exposure of mammalian skin induces local and systemic immunosuppression. In mice it has been proposed that systemic immunosuppression is mediated by an UV-induced cytokine cascade involving systemic interleukin (IL)-4 and IL-10 and a reduction in IL-12 activity. To investigate whether there was a parallel mechanism in humans we examined the effect of whole-body narrowband ultraviolet B (UVB) (311,313 nm; TL-01) and ultraviolet A (UVA)-1 (340,400 nm) on serum cytokine levels. Methods/Results: In a first study, five male psoriatic subjects were whole-body irradiated with three sessions of a standard UVB (TL-01) phototherapy regimen previously shown to cause downregulation of natural killer cell activity and T helper 1 (Th1) and Th2 cytokine production by peripheral blood mononuclear cells. Enzyme-linked immunoabsorbent assay (ELISA) of sera taken before and after the third session showed no effect of phototherapy on IL-10 and tumour necrosis factor-, (TNF-,). In a second study, five healthy subjects received three whole-body exposures of UVB (TL-01) and five other healthy subjects received three exposures of UVA-1 on alternate days (total 22 J/cm2). Blood samples were taken before the first irradiation and at 0, 4, 8, 12, 14, 24 and 48 h after the third irradiation. The sera were subsequently analysed for IL-10, IL-12, IL-8, IL-1, and TNF-,, by ELISA. The levels of IL-1, and TNF-, were below detection limits (<5 pg/ml), while no significant change in the levels of IL-10, IL-12 or IL-8 was detected as a result of either TL-01 or UVA-1. Conclusion: It seems unlikely that a modulation in these circulating cytokines assessed in this study accounts for systemic UV-induced immunosuppression in human subjects. [source] Ultraviolet reflectance and cryptic sexual dichromatism in the ocellated lizard, Lacerta (Timon) lepida (Squamata: Lacertidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009ENRIQUE FONT Ultraviolet (UV) colorations have garnered extensive theoretical and empirical treatment in recent years, although the majority of studies have concerned themselves with avian taxa. However, many lizards have acute visual systems with retinal photoreceptors that are sensitive to UV wavelengths, and also display UV-reflecting colour patches. In the present study, we used UV photography and full-spectrum reflectance spectrophotometry to describe intra- and intersexual colour variation in adult ocellated lizards Lacerta (Timon) lepida and to obtain evidence of UV-based ornamentation. We also investigated whether any colour traits correlate with morphological traits potentially related to individual quality. The results obtained show that the prominent eyespots and blue outer ventral scales (OVS) that ocellated lizards have on their flanks reflect strongly in the UV range and are best described as UV/blue in coloration. The eyespots of males are larger and cover a larger surface area than those of females. However, these differences can be entirely accounted for by sex differences in body size, with males being generally larger than females. We also found differences in the shape of reflectance curves from males and females, with the eyespots and blue OVS of males being more UV-shifted than those of females. Other body regions have extremely low UV reflectance and are not sexually dichromatic. Eyespot size and the total surface area covered by eyespots increases with body size in males but not in females, suggesting that they may be signalling an intrinsic individual characteristic such as body size or male fighting ability. We also discuss the alternative and non-exclusive hypothesis that eyespots may function in lizards of both sexes as protective markings against predators. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 766,780. [source] | ||||||||||||||||||||||||||||