WorldWideScience

Sample records for higher uv resistance

  1. Improving UV Resistance of High Performance Fibers

    Science.gov (United States)

    Hassanin, Ahmed

    % rutile TiO2 nanoparticles showed excellent protection of braid from PBO. Only 7.5% strength loss was observed. To optimize the degree of protection of the sheath loaded with UV blocker particles, computational models were developed to optimize the protective layer thickness/weight and the amount of UV particles that provide the maximum protection with lightest weight of the protective layer and minimum amount of UV particles. The simulated results were found to be higher that the experimental results due to the tendency of nanoparticles to be agglomerated in real experiments. The third approach to achieve a maximum protection with the minimum weight added is constructing a sleeve from SpectraRTM (Ultra High Molecular Weight Polyethylene (UHMWPE) high performance fiber), which is known to resist UV, woven fabric. Covering the braid from PBO fiber with Spectra RTM woven fabric provide hybrid structure with two compatible components that can share the load and thus maintain the high strength to weight ratio. Although the SpectraRTM fabric had maximum cover factor, 20 % of visible light and about 15 % of UV were able to penetrate the fabric. This transmittance of UV-VIS light negatively affected the protection performance of the SpectraRTM woven fabric layer. It is thought that SpectraRTM fabric be coated with a thin layer (mentioned earlier) containing UV blocker for additional protection while maintain strength contribution to the hybrid structure. To maximize the strength to weight ratio of the hybrid structure (with core from PBO braid and sheath from SpectraRTM woven fabric) an established finite element model was utilized. The theoretical results using the finite element theory indicated that by controlling the bending rigidity of the filling yarn of the SpectraRTM fabric, the extension at peak load of woven fabric in warp direction (loading direction) could be controlled to match the braid extension at peak load. The match in the extension at peak load of the two

  2. Risks of increased UV-B radiation: higher plants

    International Nuclear Information System (INIS)

    Rau, W.; Hofmann, H.

    1994-01-01

    The question pursued within the Bavarian climate research programme (BayFORKLIM) in the present context was as follows: Does the fact that UV-B radiation increases with growing site elevation mean that the low sensitivity of predominantly alpine plants compared with that of lowland plants is attributable to their different genetic constitution, possibly as a result of selective pressure and/or de alpine species have a greater capacity to develop protective mechanisms? Pairs and triplets of species belonging to the same genus but occuring at different site elevations were grown from seeds in a greenhouse that is, without UV-B. In order to determine their capacity to adapt to UV-B radiation, some of the plants were additionally exposed to UV-B for 5-6 weeks prior to sensitivity testing. Sensitivity was tested by exposing the plants to additional UV-B of different intensities in test chambers. Visible damage, ranging from light bronzing or yellowing to withering, served as an assessment criterion. Levels of UV-B absorbing substances (phenylpropane species, usually flavonoids) were also measured in these plants. The results obtained permit the following conclusions: The greater UV-B resistance of alpine species compared with that of lowland species of the same genus is not attributable to their genetic constitution but rather to their superior adaptability. Superior resistance is in part due to a greater accumulation of UV-B absorbing substances. Distinct differences in sensitivity between different genera could lead to population shifts within ecosystems as a result of increased UV-B radiation. (orig./KW) [de

  3. Effect of UV on DNA synthesis in UV-resistant insect cells

    International Nuclear Information System (INIS)

    Styer, S.C.; Meechan, P.J.; Griffiths, T.D.

    1987-01-01

    Insect cells are most resistant to killing by 254 nm ultraviolet light (UV) than mammalian cells. Because they have an active photolyase, it may be possible to generate a higher number of [6-4] PyC lesions per genome, allowing the possibility to distinguish between the effects of [5-6] pyrimidine lesions and the nonphotoreactable [6-4] lesions on DNA replication. IAL-PID2 cells, derived from imaginal wing discs of the Indian meal moth were exposed to UV followed by photoreactivating light (PR) or sham treatment and then analyzed by measuring the incorporation of [/sup 3/H]-thymidine into acid precipitable form. As expected, there was a fluence-dependent decrease in the amount of thymidine incorporated after exposure to UV. The response was similar to that observed in wild type CHO cells (AAS) except that the rate of decline was more rapid. When PR followed UV, there was less of a decline in thymidine incorporation and a more rapid recovery. However, thymidine incorporation did not return to control levels as rapidly as expected if [5-6] lesions were the only lesions involved in the disruption of DNA synthesis after exposure to UV

  4. Effects of UV light disinfection on antibiotic-resistant coliforms in wastewater effluents

    International Nuclear Information System (INIS)

    Meckes, M.C.

    1982-01-01

    Total coliforms and total coliforms resistant to streptomycin, tetracycline, or chloramphenicol were isolated from filtered activated sludge effluents before and after UV light irradiation. Although the UV irradiation effectively disinfected the wastewater effluent, the percentage of the total surviving coliform population resistant to tetracycline or chloramphenicol was significantly higher than the percentage of the total coliform population resistant to those antibiotics before UV irradiation. This finding was attributed to the mechanism of R-factor mediated resistance to tetracycline. No significant difference was noted for the percentage of the surviving total coliform population resistant to streptomycin before or after UV irradiation. Multiple drug resistant to patterns of 300 total coliform isolates revealed that 82% were resistant to two or more antibiotics. Furthermore, 46% of these isolates were capable of transferring antibiotic resistance to a sensitive strain of Escherichia coli

  5. Increased resistance of environmental anaerobic spores to inactivation by UV

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Veer, A.J. van der; Beerendonk, E.F.; Medema, Gerriet Jan

    2004-01-01

    Water Company Europoort started a pilot plant (MP)UV study to determine the UV-fluence to meet the Dutch drinking water standards. The results of large volume sampling of this pilot plant demonstrated that environmental spores of sulphite-reducing clostridia (SSRC) were highly resistant against UV.

  6. Enhanced expression of transferrin receptor confers UV-resistance in human and monkey cells

    International Nuclear Information System (INIS)

    Chen, Zheng; Nomura, Jun; Suzuki, Toshikazu; Suzuki, Nobuo

    2005-01-01

    One of the most intriguing biological subjects is cell-surface molecules that regulate the susceptibility of human cells to cell-killing effects after irradiation with far-ultraviolet light (UV, principally 254 nm wavelength). Human RSa cells have unusual sensitivity to UV-induced cell-killing. We searched for molecules on the cell-surface of RSa cells that were present in different amounts as compared to a variant of these cells, UV r -1 cells, which have increased resistance to UV cell-killing. Among the 21 molecules examined, the amount of transferrin receptor (TfR) protein was found to be 2-fold higher in UV r -1 cells compared with in RSa cells. The amounts of this protein were also higher in the UV-resistant hematopoietic cell lines, CEM6 and Daudi, as compared to the UV-sensitive cell lines, Molt4 and 697. Culturing of UV r -1 cells in a medium containing anti-transferrin antibodies resulted in sensitization of the cells to UV cell-killing as demonstrated by colony formation assay. Similar results were observed by treatment of the cells with TfR siRNA. In contrast, overexpression of TfR protein led to a resistance to UV cell-killing in RSa cells and monkey COS7 cells as demonstrated by both colony formation and apoptosis assay. In TfR-overexpressing cells, reduction of p53 and Bax protein was observed after UV-irradiation. Thus, TfR expression appears to be involved in the regulation of UV-resistance, possibly via modulation of the amount of p53 and Bax protein. (author)

  7. Resistance of human and mouse myeloid leukemia cells to UV radiation

    International Nuclear Information System (INIS)

    Poljak-Blazi, M.; Osmak, M.; Hadzija, M.

    1989-01-01

    Sensitivity of mouse bone marrow and myeloid leukemia cells and sensitivity of human myeloid leukemia cells to UV light was tested. Criteria were the in vivo colony-forming ability of UV exposed cells and the inhibition of DNA synthesis during post-irradiation incubation for 24 h in vitro. Mouse bone marrow cells irradiated with a small dose of UV light (5 J/m 2 ) and injected into x-irradiated animals did not form hemopoietic colonies on recipient's spleens, and recipients died. However, mouse leukemia cells, after irradiation with higher doses of UV light, retained the ability to form colonies on the spleens, and all recipient mice died with typical symptoms of leukemia. In vitro, mouse bone marrow cells exhibited high sensitivity to UV light compared to mouse myeloid leukemia cells. Human leukemia cells were also resistant to UV light, but more sensitive than mouse leukemia cells. (author)

  8. Different levels of UV-B resistance in Vaccinium corymbosum cultivars reveal distinct backgrounds of phenylpropanoid metabolites.

    Science.gov (United States)

    Luengo Escobar, Ana; Magnum de Oliveira Silva, Franklin; Acevedo, Patricio; Nunes-Nesi, Adriano; Alberdi, Miren; Reyes-Díaz, Marjorie

    2017-09-01

    UV-B radiation induces several physiological and biochemical effects that can influence regulatory plant processes. Vaccinium corymbosum responds differently to UV-B radiation depending on the UV-B resistance of cultivars, according to their physiological and biochemical features. In this work, the effect of two levels of UV-B radiation during long-term exposure on the phenylpropanoid biosynthesis, and the expression of genes associated with flavonoid biosynthesis as well as the absolute quantification of secondary metabolites were studied in two contrasting UV-B-resistant cultivars (Legacy, resistant and Bluegold, sensitive). Multivariate analyses were performed to understand the role of phenylpropanoids in UV-B defense mechanisms. The amount of phenylpropanoid compounds was generally higher in Legacy than in Bluegold. Different expression levels of flavonoid biosynthetic genes for both cultivars were transiently induced, showing that even in longer period of UV-B exposure; plants are still adjusting their phenylpropanoids at the transcription levels. Multivariate analysis in Legacy indicated no significant correlation between gene expression and the levels of the flavonoids and phenolic acids. By contrast, in the Bluegold cultivar higher number of correlations between secondary metabolite and transcript levels was found. Taken together, the results indicated different adjustments between the cultivars for a successful UV-B acclimation. While the sensitive cultivar depends on metabolite adjustments to respond to UV-B exposure, the resistant cultivar also possesses an intrinsically higher antioxidant and UV-B screening capacity. Thus, we conclude that UV-B resistance involves not only metabolite level adjustments during the acclimation period, but also depends on the intrinsic metabolic status of the plant and metabolic features of the phenylpropanoid compounds. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants

    Directory of Open Access Journals (Sweden)

    Qingxia Zhong

    2017-10-01

    Full Text Available The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat, and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

  10. Hypermutability of a UV-sensitive aphidicolin-resistant mutant of Chinese hamster fibroblasts

    International Nuclear Information System (INIS)

    Liu, P.K.; Chang, C.; Trosko, J.E.

    1982-01-01

    An ultraviolet light (UV)-sensitive thymidine auxotroph of Chinese hamster V79 cells that exhibits pleiotropic effects such as a high level of deoxycytidine triphosphate, slow growth, sensitivity to cytidine, and high frequencies of site-specific bromodeoxyuridine-dependent chromosomal aberrations was selected by its resistance to aphidicolin. The UV-induced mutability of this mutant and one of its revertants, which retains some of the phenotypes listed above, was studied in 3 mutation assay systems. The results showed that the mutant was hypermutable for ouabain and diphtheria-toxin-resistant mutations compared to wild-type V79 cells at the same UV dose or the same survival level. The mutant exhibits a delayed expression of maximal frequency of induced 6-thioguanine-resistant mutants. When maximal frequencies are compared at the same UV dose, the mutant also has higher mutation frequencies at the hypoxanthine-guanine phosphoribosyl transferase locus. The revertant was similar to the wild-type in UV sensitivity and mutability. (orig./AJ)

  11. Resistance to change in Greek higher education

    OpenAIRE

    Kremmyda, Stamatia

    2015-01-01

    This thesis is a study of resistance to the changes in Greek higher education that were implemented within the framework of the 1999 Bologna Agreement of the European Union in the period 2007-2008. The changes that occurred were of great significance for Greece’s education system as they introduced important changes in the structure and function of Greek higher education. This thesis argues that the organisational culture that had been created throughout the history of Greek higher education ...

  12. Induced resistance to hydrogen peroxide, UV and gamma radiation in bacillus species

    International Nuclear Information System (INIS)

    Bashandy, A.S.

    2005-01-01

    The catalase activity produced in four bacillus spp.(bacillus cereus, B. laterosporus, B. pumilus and B. subtilis (Escherichia coli was used for comparison) was measured and the sensitivity of these bacteria to hydrogen peroxide was tested. Bacillus spp. had higher resistance to hydrogen peroxide than E. coil. cultures of bacillus spp . When pretreated with sublethal level of hydrogen peroxide, became relatively resistant to the lethal effects of hydrogen than untreated control cultures. These pretreated cells were also resistant to lethality mediated by UV light and gamma radiation. The obtained results suggest that bacillus spp. Possess inducible defense mechanism (s) against the deleterious effects of oxidants and /or ionizing radiation

  13. Higher plants and UV-B radiation: balancing damage, repair and acclimation

    International Nuclear Information System (INIS)

    Jansen, M.A.K.; Gaba, V.; Greenberg, B.M.

    1998-01-01

    Although UV-B is a minor component of sunlight, it has a disproportionately damaging effect on higher plants. Ultraviolet-sensitive targets include DNA, proteins and membranes, and these must be protected for normal growth and development. DNA repair and secondary metabolite accumulation during exposure to UV-B have been characterized in considerable detail, but little is known about the recovery of photosynthesis, induction of free-radical scavenging and morphogenic changes. A future challenge is to elucidate how UV-B-exposed plants balance damage, repair, acclimation and adaptation responses in a photobiologically dynamic environment. (author)

  14. Molecular processes as basis for plasmid-mediated bacterial UV-light resistance and mutagenesis

    International Nuclear Information System (INIS)

    Aleshkin, G.I.; Brukhanskij, G.V.; Skavronskaya, A.G.

    1985-01-01

    The increase of UV-resistance and UV-induced mutagenesis by lambda 1 pint intmid as well as molecular-genetic mechanisms of plasmid participation in reparation and DNA replication and its degradation after UV-irradiation in plasmid cells on pKM101 plasmid model have been investigated. Data testifying to the necessity of intmid integration in chromosome as obligatory stage of intmid participation in increasing UV-resistance of bacterial cells are obtained. It has been found that intmid raises UV-resistance of cells and increases respectively the UV-induced reverants efficiency. On the basis of the experiment data the conclusion is drawn that the intmid capacity to raise UV-resistance and, possibly, mutagenesis is bound not only with its integration into chromosome but also with pol A + chromosome replication by dependendent imtmid replication complex. It is shown that pKM101 plasmid ensures functioning in E coli cells of inducible, chloroamphenicol-resistant DNA replication, highly resistant to UV-light harmful effect and that the volume of excision reparation in E. coli cells carrying pKM101 plasmid is increased as compared with the volume of reparation in plasmid legs cells. The combination of the data obtained gives grounds to the authors to assume that inducible replication, inducible reparation of DNA and inducible decrease of DNA degradation determined by pKM101 plasmid may serve as recA + lexA + basis dependent increase of UV-resistance and mutagenesis and that these processes provide the possibility of functioning of integrative replication mechanism of plasmid participation in ensuring UV-resistance and mutagenesis of plants

  15. Genetic study of resistance to inhibitory effects of UV radiation in rice (Oryza sativa)

    International Nuclear Information System (INIS)

    Sato, T.; Kang, H.S.; Kumagai, T.

    1994-01-01

    Genetic analysis of resistance to the inhibitory effects of UV radiation on growth of rice (Oryza sativa L.) cultivars was carried out. Some experimental plants were grown in visible radiation supplemented with UV radiation containing a large amount of UV-B and a small amount of UV-C in a phytotron, while others were grown without UV radiation. The degree of resistance to UV radiation was estimated in terms of the degree of reduction caused by supplemental UV radiation in the fresh weight of the aboveground plant parts and the chlorophyll content per unit fresh weight. Fresh weight and chlorophyll content in F 2 plants generated by reciprocally crossing cv. Sasanishiki, a cultivar more resistant to UV radiation, and Norin 1, a cultivar less resistant to such radiation exhibited a normal frequency distribution. The heritabilities of these two properties in F 2 plants were low under conditions of non-supplemental UV radiation. Under elevated UV radiation, the F 2 population shifted to the lower range of fresh weight and chlorophyll content, and the means were close to those of Norin 1. The heritabilities of these two properties were the same in the reciprocal crosses, indicating that maternal inheritance was not involved. Inheritance of chlorophyll content per unit fresh weight was further determined in F 3 lines generated by self-fertilizing F 2 plants of Sasanishiki and Norin 1. The results showed that the F 3 population was segregated into three genotypes, namely, resistant homozygotes, segregated heterozygotes and sensitive homozygotes, with a ratio of 1:65:16. It was thus evident that the resistance to the inhibitory effect of elevated UV radiation in these rice plants was controlled by recessive polygenes. (author)

  16. Plasmid mediated enhancement of uv resistance in Streptococcus faecalis

    International Nuclear Information System (INIS)

    Miehl, R.; Miller, M.; Yasbin, R.E.

    1980-01-01

    A 38.5-Mdal plasmid of Streptococcus faecalis subdp. zymogenes has been shown to enhance survival following uv irradiation. In addition, the presence of this plasmid increases the mutation frequencies following uv irradiation and enhanced W-reactivation. The data presented indicate that S. faecalis has an inducible error-prone repair system and that the plasmid enhances these repair functions

  17. A Study of UV Resistance of a Water-based Polyurethane Lacquer Containing Nano Ceria

    Directory of Open Access Journals (Sweden)

    Arash Saadat-Monfared

    2013-01-01

    Full Text Available Cerium oxide (Ceria nano particle, as photodegradation prevention agent was studied in water-based polyurethane clear coat  systems. Polyurethane coatings show superior weathering resistance compared with acrylic melamine systems. However, any chemical change has detrimental effects on the property profile of PU coatings. Coatings containing various amounts of cerium oxide nanoparticles were prepared and their weathering resistance was evaluated using simulated UV cabinet. To this end the extent and mechanism of degradation was studied utilizing UV-Vis and FTIR-ATR spectroscopy as well as DMTA analysis. The results revealed that Ceria nano particles with concentration of 1.44 % (wt absorb beyond 92.5% of UV light of UV-B region and showed an efficiency of 2000 times as of organic UV absorbers.

  18. Heat and UV light resistance of vegetative cells and spores of Bacillus subtilis rec-mutants

    International Nuclear Information System (INIS)

    Hanlin, J.H.; Lombardi, S.J.; Slepecky, R.A.

    1985-01-01

    The heat and UV light resistance of spores and vegetative cells of Bacillus subtilis BD170 (rec+) were greater than those of B. subtilis BD224 (recE4). Strain BD170 can repair DNA whereas BD224 is repair deficient due to the presence of the recE4 allele. Spores of a GSY Rec+ strain were more heat resistant than spores of GSY Rec- and Uvr- mutants. The overall level of heat and UV light resistance attained by spores may in part be determined by their ability to repair deoxyribonucleic acid after exposure to these two physical mutagens

  19. UV resistibility of a nano-ZnO/glass fibre reinforced epoxy composite

    International Nuclear Information System (INIS)

    Wong, Tsz-ting; Lau, Kin-tak; Tam, Wai-yin; Leng, Jinsong; Etches, Julie A.

    2014-01-01

    Highlights: • A GFRE composite with UV resistibility is introduced. • The bonding behaviour and UV resistibility of the composite were studied upon the addition of nano-ZnO particles. • The solvent effect in the dispersion of nano-ZnO particles was also studied. • The nano-ZnO/GFRE composite shows effective UV absorption with enhanced bonding behaviour. - Abstract: The harmfulness of ultraviolet (UV) radiation (UVR) to human health and polymer degradation has been the focus recently in all engineering industries. A polymer-based composite filled with nano-ZnO particles can enhance its UV resistibility. It has been found that the use of appropriate amount of nano-ZnO/Isopropyl alcohol solvent to prepare a UV resistant nano-ZnO/glass fibre reinforced epoxy (ZGFRE) composite can effectively block the UV transmission with negligible influence on the crystal structure of its resin system. This paper aims at investigating the interfacial bonding behaviour and UV resistibility of a ZGFRE composite. The solvent effect in relation to the dispersion properties of ZnO in the composite is also discussed. XRD results indicated that 20 wt% Isopropyl alcohol was an effective solvent for filling nano-ZnO particles into an epoxy. SEM examination also showed that the bonding behaviour between glass fibre and matrix was enhanced after filling 20 wt% nano-ZnO particles with 20 wt% Isopropyl alcohol into the composite. Samples filled with 20 wt% nano-ZnO/Isopropyl alcohol and 40 wt% nano-ZnO/Isopropyl alcohol has full absorption of UVA (315–400 nm), UVB (280–315 nm) and a part of UVC (190–280 nm)

  20. Comparison of higher irradiance and black panel temperature UV backsheet exposures to field performance

    Science.gov (United States)

    Felder, Thomas C.; Gambogi, William J.; Phillips, Nancy; MacMaster, Steven W.; Yu, Bao-Ling; Trout, T. John

    2017-08-01

    The need for faster PV qualification tests that more accurately match field observations is leading to tests with higher acceleration levels, and validating the new tests through comparison to field data is an important step. We have tested and compared a wide panel of backsheets according to a proposed new backsheet UV exposure qualification standard from the International Electrotechnical Commission (IEC). Weathering Technical Standard IEC 62788-7-2 specifies higher irradiance and higher black panel temperature UV Xenon exposures. We tested PVF, PVDF, PET, PA and FEVEbased backsheets in glass laminates and simple backsheet coupons in UV exposure condition A3 (0.8W/sqmnm@340nm and 90° C BPT) We find mild yellowing with no mechanical loss in the original lower intensity ASTM G155 0.55 W/sqm-nm 70C BPT exposure condition. The new A3 exposures creates mechanical loss in sensitive backsheets, with no effect on known durable backsheets. Results from the new exposure are closer to field mechanical loss data.

  1. Evaluation of microlithographic performance of 'deep UV' resists ...

    Indian Academy of Sciences (India)

    demand newer resists for high resolution geometry. A great deal of ... the wavelength of exposure, emissions of high-pressure mercury lamps ... liquid BHMC. 2.70 g of ..... 28 2611. 23. Sebenik A, Lapanje S 1975 J. Chromatography 106 454.

  2. Liposomogenic UV Absorbers are Water-Resistant on Pig Skin-A Model Study With Relevance for Sunscreens.

    Science.gov (United States)

    Herzog, Bernd; Hüglin, Dietmar; Luther, Helmut

    2017-02-01

    An important property of sunscreens is their water resistance after the application on human skin. In this work, the hypothesis that UV absorber molecules which are able to form liposomes, so-called liposomogenic UV absorbers, show better water resistance on a pig skin model than UV-absorbing molecules lacking this ability was tested. The assumption behind is that molecules which can form liposomes are able to integrate into the stratum corneum lipids of the skin. Three different liposomogenic UV absorbers were synthesized and their behavior investigated, leading to the confirmation of the hypothesis. With one of the liposomogenic UV absorbers, it was possible to show the integration of the UV absorber molecules into the bilayers of another liposome consisting of phosphatidylcholine, supporting the assumption that liposomogenic UV absorbers exhibit improved water resistance because they integrate into the skin lipids. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  3. The solar UV environment and bacterial spore UV resistance: considerations for Earth-to-Mars transport by natural processes and human spaceflight

    Science.gov (United States)

    Nicholson, Wayne L.; Schuerger, Andrew C.; Setlow, Peter

    2005-01-01

    The environment in space and on planets such as Mars can be lethal to microorganisms because of the high vacuum and high solar radiation flux, in particular UV radiation, in such environments. Spores of various Bacillus species are among the organisms most resistant to the lethal effects of high vacuum and UV radiation, and as a consequence are of major concern for planetary contamination via unmanned spacecraft or even natural processes. This review focuses on the spores of various Bacillus species: (i) their mechanisms of UV resistance; (ii) their survival in unmanned spacecraft, space flight and simulated space flight and Martian conditions; (iii) the UV flux in space and on Mars; (iv) factors affecting spore survival in such high UV flux environments.

  4. The solar UV environment and bacterial spore UV resistance: considerations for Earth-to-Mars transport by natural processes and human spaceflight

    International Nuclear Information System (INIS)

    Nicholson, Wayne L.; Schuerger, Andrew C.; Setlow, Peter

    2005-01-01

    The environment in space and on planets such as Mars can be lethal to microorganisms because of the high vacuum and high solar radiation flux, in particular UV radiation, in such environments. Spores of various Bacillus species are among the organisms most resistant to the lethal effects of high vacuum and UV radiation, and as a consequence are of major concern for planetary contamination via unmanned spacecraft or even natural processes. This review focuses on the spores of various Bacillus species: (i) their mechanisms of UV resistance; (ii) their survival in unmanned spacecraft, space flight and simulated space flight and Martian conditions; (iii) the UV flux in space and on Mars; (iv) factors affecting spore survival in such high UV flux environments

  5. The solar UV environment and bacterial spore UV resistance: considerations for Earth-to-Mars transport by natural processes and human spaceflight

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, Wayne L. [Department of Microbiology and Cell Science, University of Florida, Mail Code UF-1, Building M6-1025/SLSL, Kennedy Space Center, FL 32899 (United States)]. E-mail: WLN@ufl.edu; Schuerger, Andrew C. [Department of Plant Pathology, University of Florida, Mail Code UF-1, Space Life Sciences Laboratory, Kennedy Space Center, FL 32899 (United States)]. E-mail: acschuerger@ifas.ufl.edu; Setlow, Peter [Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030 (United States)]. E-mail: setlow@nso2.uchc.edu

    2005-04-01

    The environment in space and on planets such as Mars can be lethal to microorganisms because of the high vacuum and high solar radiation flux, in particular UV radiation, in such environments. Spores of various Bacillus species are among the organisms most resistant to the lethal effects of high vacuum and UV radiation, and as a consequence are of major concern for planetary contamination via unmanned spacecraft or even natural processes. This review focuses on the spores of various Bacillus species: (i) their mechanisms of UV resistance; (ii) their survival in unmanned spacecraft, space flight and simulated space flight and Martian conditions; (iii) the UV flux in space and on Mars; (iv) factors affecting spore survival in such high UV flux environments.

  6. Abscisic acid and ethylene in mutants of Arabidopsis thaliana differing in their resistance to ultraviolet (UV-B) radiation stress

    International Nuclear Information System (INIS)

    Rakitina, T.Ya.; Vlasov, P.V.; Jalilova, F.Kh.; Kefeli, V.I.

    1994-01-01

    The effects of ultraviolet irradiation (between 280 and 320 nm) on plant survival, ethylene evolution, and abscisic acid (ABA) content were studied in Arabidopsis thaliana (L.) Heunh. plants. Three genetic lines of Arabidopsis differing in their resistance to ultraviolet (UV-B) radiation stress were used. UV-B irradiation had detrimental effects on plant survival, enhanced ethylene evolution, and increased ABA content in the plants of all three lines. The higher ultraviolet dose was absorbed, the less was the number of surviving plants and the higher were the levels of both phytohormones. The maximum ethylene evolution occurred during the initial two to four hours after irradiation, but the ABA content peaked only after 24 h. The most resistant line showed the highest ABA content and the fastest ethylene evolution, whereas, in the susceptible line, both indices were the lowest. After UV-B treatment, the ABA-deficient Arabidopsis mutant evolved four to six times more ethylene than the plants with normal ABA content. Stress ethylene production evidently did not depend on the level of endogenous ABA as the kinetics of ethylene evolution was similar in the ABA-deficient mutant and in other studied Arabidopsis lines

  7. Optimization of droplets for UV-NIL using coarse-grain simulation of resist flow

    Science.gov (United States)

    Sirotkin, Vadim; Svintsov, Alexander; Zaitsev, Sergey

    2009-03-01

    A mathematical model and numerical method are described, which make it possible to simulate ultraviolet ("step and flash") nanoimprint lithography (UV-NIL) process adequately even using standard Personal Computers. The model is derived from 3D Navier-Stokes equations with the understanding that the resist motion is largely directed along the substrate surface and characterized by ultra-low values of the Reynolds number. By the numerical approximation of the model, a special finite difference method is applied (a coarse-grain method). A coarse-grain modeling tool for detailed analysis of resist spreading in UV-NIL at the structure-scale level is tested. The obtained results demonstrate the high ability of the tool to calculate optimal dispensing for given stamp design and process parameters. This dispensing provides uniform filled areas and a homogeneous residual layer thickness in UV-NIL.

  8. A UV-resistant mutant without an increased repair synthesis activity, established from a UV-sensitive human clonal cell line

    International Nuclear Information System (INIS)

    Suzuki, N.

    1984-01-01

    When cells of a human clonal cell line, RSa, with high sensitivity to UV lethality, were treated with the mutagen, ethyl methanesulfonate, a variant cell strain, UVr-1, was established as a mutant resistant to 254-nm far-ultraviolet radiation (UV). Cell proliferation studies showed that UVr-1 cells survived and actively proliferated at doses of UV-irradiation that greatly suppressed the proliferation of RSa cells. Colony-formation assays also confirmed the increased resistance of UVr-1 cells to UV. The recovery from a UV-induced inhibition in DNA synthesis, as [methyl- 3 H]thymidine uptake into cellular DNA, was more pronounced in UVr-1 cells than in RSa cells. Nevertheless, there was no significant difference in the activity of UV-induced DNA repair synthesis in either cell line, as estimated by the extent of unscheduled DNA synthesis and DNA repair replication. These characteristics of UVr-1 cells are discussed in the light of a previously reported UV-resistant variant, UVr-10, which had an increased DNA repair synthesis activity. (Auth.)

  9. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi.

    Science.gov (United States)

    Lando, Gabriela Albara; Marconatto, Letícia; Kessler, Felipe; Lopes, William; Schrank, Augusto; Vainstein, Marilene Henning; Weibel, Daniel Eduardo

    2017-07-18

    Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU) are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae , when the films were pre-treated with Ultraviolet (UV) irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), scanning electron microscopy (SEM), and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  10. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Gabriela Albara Lando

    2017-07-01

    Full Text Available Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae, when the films were pre-treated with Ultraviolet (UV irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR, scanning electron microscopy (SEM, and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  11. Water-resistant sunscreens for skin protection: an in vivo approach to the two sources of sunscreen failure to maintain UV protection on consumer skin.

    Science.gov (United States)

    Puccetti, G

    2015-12-01

    The water resistance of sunscreen products has taken more importance for the UV protection of consumers involved in water activities and sports. The present work introduces a new in vivo approach to measure the water resistance of sunscreens on the actual skin of subjects, which can be easily applied to salt, chlorine and tap waters. The stress sources of sunscreen films on skin originate from two phenomena: high surface tension stress as the skin transits through the air/water interface and water diffusion into the film immersed in bulk water. The water resistance of sunscreen products is measured on the forearms of subjects by means of a new layered water bath approach that physically separates both stresses. Tape strips are subsequently taken and analysed for UV-A and UV-B optical densities via (1) imaging for remaining filters and (2) in vitro SPF absorption spectra. Water-resistant sunscreens generally perform well when immersed in bulk water even subjected to agitation, but they show a wide range of performances when considering their behaviour at the air/water interface. The differences are more pronounced in salt water than tap water. The results confirm 2 stress origins in sunscreen exposure to water: interfacial surface tension and bulk water diffusion. Polymers bring improvements to the resistance of sunscreens to bulk water but show wide latitude in performances when subject to the water surface tension stress. Globally, a higher loss of filters is observed in the UV-A than in the UV-B, which is attributed to more UV-A filter loss or degradation and thus resulting in a decreased protection in the UV-A. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  12. Multiple-height microstructure fabricated by deep reactive ion etching and soft resist masks combined with UV curing

    International Nuclear Information System (INIS)

    Sato, R; Sawada, T; Kumagai, S; Sasaki, M

    2014-01-01

    Multiple-height microstructures are realized by deep reactive ion etching and UV-cured photoresist used in the embedded mask process. Although the UV-cured photoresist is a soft mask, its material property becomes stable against resist thinner and UV exposure. A layered resist pattern can be realized by stacking normal photoresist on the UV-cured photoresist. The normal photoresist can be selectively removed by the flush exposure and developing after the first Si etching. This technique is applied to two MEMS devices

  13. Cloning in Streptococcus lactis of plasmid-mediated UV resistance and effect on prophage stability

    International Nuclear Information System (INIS)

    Chopin, M.C.; Chopin, A.; Rouault, A.; Simon, D.

    1986-01-01

    Plasmid pIL7 (33 kilobases) from Streptococcus lactis enhances UV resistance and prophage stability. A 5.4-kilobase pIL7 fragment carrying genes coding for both characters was cloned into S. lactis, using plasmid pHV1301 as the cloning vector. The recombinant plasmid was subsequently transferred to three other S. lactis strains by transformation or protoplast fusion. Cloned genes were expressed in all tested strains

  14. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ren, Hongqiang, E-mail: hqren@nju.edu.cn; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L{sup −1}. The transformation kinetic data for ARGs removal (log C{sub 0} / C) followed the second-order reaction kinetic model with FC dosage (R{sup 2} = 0.6829–0.9999) and contact time (R{sup 2} = 0.7353–8634), respectively. Higher ammonia nitrogen (NH{sub 3}–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl{sub 2}:NH{sub 3}–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm{sup −2}, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - Highlights: • Chlorine is more effective than UV irradiation in removing ARGs from MWTP effluent. • The chlorination reaction followed the second-order reaction kinetic model. • Higher NH{sub 3}–N contents result in lower ARGs removal in the chlorination process. • FC is more effective than CC on the inactivation of ARGs. • UV irradiation followed by chlorination shows high efficiency in removing ARGs.

  15. UV light-induced survival response in a highly radiation-resistant isolate of the Moraxella-acinetobacter group

    International Nuclear Information System (INIS)

    Keller, L.C.; Thompson, T.L.; Maxcy, R.B.

    1982-01-01

    A highly radiation-resistant member of the Moraxella-Acinetobacter group, isolate 4, obtained from meat, was studied to determine the effect of preexposure to UV radiation on subsequent UV light resistance. Cultures that were preexposed to UV light and incubated for a short time in plate count broth exhibited increased survival of a UV light challenge dose. This response was inhibited in the presence of chloramphenicol. Frequencies of mutation to streptomycin, trimethoprim, and sulfanilamide resistance remained the same after the induction of this survival response and were not altered by treatment with mutagens, with the exception of mutation to streptomycin resistance after γ-irradiation or nitrosoguanidine or methyl methane sulfonate treatment. The results indicated that isolate 4 has a UV light-inducible UV light resistance mechanism which is not associated with increased mutagenesis. The characteristics of the radiation resistance response in this organism are similar to those of certain other common food contaminants. Therefore, considered as part of the total microflora of meat, isolate 4 and the other radiation-resistant Moraxella-Acinetobacter isolates should not pose unique problems in a proposed radappertizaton process

  16. DNA synthesis and uv resistance in Escherichia coli K12 cells

    Energy Technology Data Exchange (ETDEWEB)

    Slezarikova, V [Slovenska Akademia Vied, Bratislava (Czechoslovakia). Vyskumny Ustav Onkologicky

    1976-01-01

    The influence was studied of preirradiation inhibition of proteosynthesis by amino acids starvation on survival and DNA synthesis in E. coli K 12 cells, which differ by their genetic features with regard to a certain type of repair. The surviving fraction was studied by appropriate dilution of cell suspension and spreading on agar plates. DNA synthesis was investigated by the incorporation of thymine-2-/sup 14/C. In our conditions a correlation was found between cell survival and the resistance of DNA replication to UV radiation in cells proficient in excision and post-replication repair. This correlation was not found in the excision deficient strain. It is concluded that enhanced resistance of DNA replication is not a sufficient condition for enhanced cell resistance.

  17. Inactivation efficiency of plasmid-encoded antibiotic resistance genes during water treatment with chlorine, UV, and UV/H2O2.

    Science.gov (United States)

    Yoon, Younggun; Chung, Hay Jung; Wen Di, Doris Yoong; Dodd, Michael C; Hur, Hor-Gil; Lee, Yunho

    2017-10-15

    This study assessed the inactivation efficiency of plasmid-encoded antibiotic resistance genes (ARGs) both in extracellular form (e-ARG) and present within Escherichia coli (intracellular form, i-ARG) during water treatment with chlorine, UV (254 nm), and UV/H 2 O 2 . A quantitative real-time PCR (qPCR) method was used to quantify the ARG damage to amp R (850 bp) and kan R (806 bp) amplicons, both of which are located in the pUC4K plasmid. The plate count and flow cytometry methods were also used to determine the bacterial inactivation parameters, such as culturability and membrane damage, respectively. In the first part of the study, the kinetics of E. coli inactivation and ARG damage were determined in phosphate buffered solutions. The ARG damage occurred much more slowly than E. coli inactivation in all cases. To achieve 4-log reduction of ARG concentration at pH 7, the required chlorine exposure and UV fluence were 33-72 (mg × min)/L for chlorine and 50-130 mJ/cm 2 for UV and UV/H 2 O 2 . After increasing pH from 7 to 8, the rates of ARG damage decreased for chlorine, while they did not vary for UV and UV/H 2 O 2 . The i-ARGs mostly showed lower rates of damage compared to the e-ARGs due to the protective roles of cellular components against oxidants and UV. The contribution of OH radicals to i-ARG damage was negligible in UV/H 2 O 2 due to significant OH radical scavenging by cellular components. In all cases, the ARG damage rates were similar for amp R versus kan R , except for the chlorination of e-ARGs, in which the damage to amp R occurred faster than that to kan R . Chlorine and UV dose-dependent ARG inactivation levels determined in a wastewater effluent matrix could be reasonably explained by the kinetic data obtained from the phosphate buffered solutions and the expected oxidant (chlorine and OH radicals) demands by water matrix components. These results can be useful in optimizing chlorine and UV-based disinfection systems to achieve ARG

  18. Complementation of a pKM101 derivative that decreases resistance to UV killing but increases susceptibility to mutagenesis

    International Nuclear Information System (INIS)

    Langer, P.J.; Perry, K.L.; Walker, G.C.

    1985-01-01

    The drug resistance plasmid pKM101 makes Escherichia coli resistant to the lethal effects of ultraviolet (UV) irradiation and more susceptible to mutagenesis by a variety of agents. The plasmid operon responsible for increasing mutagenesis has been termed mucAB (Mutagenesis, UV and chemical). The authors have isolated a derivative of pKM101 called pGW1975 which makes cells more sensitive to killing by UV but which retains the ability of pKM101 to increase susceptibility to methyl methanesulfonate (MMS) mutagenesis. pGW1975 increases UV mutagenesis less than pKM101 in a uvrA + strain but more than pKM101 in a uvrA - strain. muc - point and insertion mutants of pKM101 and pGW1975 complement to restore the plasmid-mediated: (i) ability to reactivate UV-irradiated phage, (ii) resistance to killing by UV, and (iii) level of susceptibility to UV mutagenesis. They have identified a 2.0 kb region of pKM101 which is responsible for the complementation and which maps counterclockwise of mucAB. (Auth)

  19. γ-irradiation resistance and UV-sensitivity of extremely thermophilic archebacteria and eubacteria

    International Nuclear Information System (INIS)

    Kopylov, V.M.; Bonch-Osmolovskaya, E.A.; Svetlichnyi, V.A.; Miroshnichenko, M.L.; Skobkin, V.S.

    1993-01-01

    Cells of extremely thermophilic sulfur-dependent archebacteria Desulfurococcus amylolyticus Z533 and Thermococcus stelleri K15 are resistant to γ-irradiation. These archebacteria survive γ-irradiation at a dose of up to 5 kGy but are no longer viable after 8-9 kGy. Comparison of the survival profiles showed that archebacteria are 12 to 25 times more resistant to γ-irradiation at moderate doses (LD 50 and LD 90 ) than E. coli K12 but are 2 to 2.5 times more sensitive than D. radiodurans. γ-irradiation at a dose of 1 to 2.5 kGy killed extremely thermophilic anaerobic eubacteria Thermotoga maritima 2706 and Thermodesulfobacterium P. All extreme thermophiles studied were more sensitive to UV-irradiation than E. coli

  20. Incorporation of Rutin in Electrospun Pullulan/PVA Nanofibers for Novel UV-Resistant Properties.

    Science.gov (United States)

    Qian, Yongfang; Qi, Mengjie; Zheng, Laijiu; King, Martin W; Lv, Lihua; Ye, Fang

    2016-06-23

    This study aimed to investigate the incorporation of rutin into electrospun pullulan and poly(vinyl alcohol) (PVA) nanofibers to obtain ultraviolet (UV)-resistant properties. The effect of weight ratios between pullulan and PVA, and the addition of rutin on the nanofibers' morphology and diameters were studied and characterized by scanning electron microscopy (SEM). Fourier transform infrared (FTIR) analysis was utilized to investigate the interaction between pullulan and PVA, as well as with rutin. The results showed that the inclusion of PVA results in the increase in the fiber's diameter. The addition of rutin had no obvious effect on the fibers' average diameters when the content of rutin was less than 7.41%. FTIR results indicated that a hydrogen bond formed between pullulan and PVA, also between these polymers and rutin. Moreover, the addition of rutin could enhance the mechanical properties due to its stiff structure and could decrease the transmittance of UVA and UVB to be fewer than 5%; meanwhile, the value of ultraviolet protection factor (UPF) reached more than 40 and 50 when the content of rutin was 4.46% and 5.67%, respectively. Therefore, the electrospun pullulan/PVA/rutin nanofibrous mats showed excellent UV resistance and have potential applications in anti-ultraviolet packaging and dressing materials.

  1. Requirements of blue, UV-A, and UV-B light for normal growth of higher plants, as assessed by actions spectra for growth and related phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, T. [Kobe Women`s Univ., Higashisuma (Japan)

    1994-12-31

    It is very important for experimental purposes, as well as for the practical use of plants when not enough sunlight is available. To grow green higher plants in their normal forms under artificial lighting constructing efficient and economically reasonable lighting systems is not an easy task. One possible approach would be to simulate sunlight in intensity and the radiation spectrum, but its high construction and running costs are not likely to allow its use in practice. Sunlight may be excessive in irradiance in some or all portions of the spectrum. Reducing irradiance and removing unnecessary wavebands might lead to an economically feasible light source. However, removing or reducing a particular waveband from sunlight for testing is not easy. Another approach might be to find the wavebands required for respective aspects of plant growth and to combine them in a proper ratio and intensity. The latter approach seems more practical and economical, and the aim of this Workshop lies in advancing this approach. I summarize our present knowledge on the waveband requirements of higher plants for the regions of blue, UV-A and UV-B.

  2. Decreased UV light resistance of spores of Bacillus subtilis strains deficient in pyrimidine dimer repair and small, acid-soluble spore proteins

    International Nuclear Information System (INIS)

    Setlow, B.; Setlow, P.

    1988-01-01

    Loss of small, acid-soluble spore protein alpha reduced spore UV resistance 30- to 50-fold in Bacillus subtilis strains deficient in pyrimidine dimer repair, but gave only a 5- to 8-fold reduction in UV resistance in repair-proficient strains. However, both repair-proficient and -deficient spores lacking this protein had identical heat and gamma-radiation resistance

  3. A constitutive damage specific DNA-binding protein is synthesized at higher levels in UV-irradiated primate cells

    International Nuclear Information System (INIS)

    Hirschfeld, S.; Levine, A.S.; Ozato, K.; Protic, M.

    1990-01-01

    Using a DNA band shift assay, we have identified a DNA-binding protein complex in primate cells which is present constitutively and has a high affinity for UV-irradiated, double-stranded DNA. Cells pretreated with UV light, mitomycin C, or aphidicolin have higher levels of this damage-specific DNA-binding protein complex, suggesting that the signal for induction can either be damage to the DNA or interference with cellular DNA replication. Physiochemical modifications of the DNA and competition analysis with defined substrates suggest that the most probable target site for the damage-specific DNA-binding protein complex is a 6-4'-(pyrimidine-2'-one)-pyrimidine dimer: specific binding could not be detected with probes which contain -TT- cyclobutane dimers, and damage-specific DNA binding did not decrease after photoreactivation of UV-irradiated DNA. This damage-specific DNA-binding protein complex is the first such inducible protein complex identified in primate cells. Cells from patients with the sun-sensitive cancer-prone disease, xeroderma pigmentosum (group E), are lacking both the constitutive and the induced damage-specific DNA-binding activities. These findings suggest a possible role for this DNA-binding protein complex in lesion recognition and DNA repair of UV-light-induced photoproducts

  4. Mechanisms Of The Dissolution Inhibition Effect And Their Application To Designing Novel Deep-UV Resists

    Science.gov (United States)

    Murata, Makoto; Koshiba, Mitsunobu; Harita, Yoshiyuki

    1989-08-01

    The dissolution inhibition effect and alkaline solubility were investigated for naphthoquinone diazides like 1,2-naphthoquinone diazide (NQD), its 5-sulfonylchloride (NQD-C) and 5-sulfonyloxybenzene (DAM), and for other compounds like sulfonylchlorides, sulfonyl esters, sulfones and a ketone which do not contain a naphthoquinone diazide moiety. As a result, it has turned out that the dissolution inhibition effect does not depend on the specific structure; namely, the naphthoquinone diazide moiety itself, but largely on the alkaline solubility of the compounds added to a novolak resin. An XPS study for the films consisting of a novolak resin and a dissolution inhibitor indicates a formation of an inhibitor-rich protective thin layer on the film surface after immersion of the film in an alkaline developer. In this paper is proposed a new third dissolution inhibition mechanism in addition to the previously reported chemical crosslinking and dipolar interaction; i.e., the alkaline insoluble protective layer inhibits the dissolution of novolak resin at the interface between the film and the developer. A new three-component type deep-UV resist has been also developed as an application of the new mechanism. The resist consists of a novolak resin, 5-diazo Meldrum's acid and a new dissolution inhibitors like phenyltosylate and p-phenylene ditosylate, which successfully improve the residual resist thickness.

  5. A novel method to prepare superhydrophobic, UV resistance and anti-corrosion steel surface

    KAUST Repository

    Isimjan, Tayirjan T.

    2012-11-01

    Both TiO 2 and SiO 2 coated steel surfaces containing micro- and nanoscale binary structures with different surface roughness were successfully fabricated by means of a facile layer by layer deposition process followed by heat treatment. The resulting surfaces were modified by the low free energy chemical PTES (1H,1H,2H,2H-Perfluorodecyltriethoxysilane). The experimental results of wettability exhibit that such modified surfaces have a strong repulsive force to water droplets, their static contact angles exceed 165°, receding angle>160°, advanced angles>170° and slide angle<1°. The resulting surfaces not only exhibit superhydrophobic properties but also show strong UV resistance (after coating SiO 2 on top of TiO 2) and strong stability to various solvents including 0.01% HCl solution. © 2012 Elsevier B.V.

  6. The roles of different excision-repair mechanisms in the resistance of Micrococcus luteus to UV and chemical mutagens

    International Nuclear Information System (INIS)

    Tao, Kazuyuki; Noda, Asao; Yonei, Shuji

    1987-01-01

    M. luteus mutants showing increased sensitivity to both UV and 4-NQO were isolated after the treatment of parental ATCC4698 strain with MNNG. The mutants were also highly sensitive to mitomycin C, cis-platinum, 8-methoxypsoralen (8-MOP) plus near-UV and angelicin plus near-UV in various degrees. With regard to host-cell reactivation ability the mutants fell into two groups. The hcr - mutants lacked the ability to reactivate UV-damaged N6 phage and were resistant to X-rays. The incision of DNA did not occur during incubation after the treatment with angelicin plus near-UV in the hcr - mutants, whereas it occurred in the parental strain. The facts indicate that the hcr - mutants are defective in the incision mechanism which has a wide substrate specificity, similar to the UVRABC nuclease of E. coli. On the other hand, the incision of DNA and the removal of UV-induced thymine dimers from DNA occurred in the hcr - mutants as well as in the parental strain, which is ascribed to the UV endonuclease activity. (Auth.)

  7. Soybean resistance to stink bugs (Nezara viridula and Piezodorus guildinii) increases with exposure to solar UV-B radiation and correlates with isoflavonoid content in pods under field conditions.

    Science.gov (United States)

    Zavala, Jorge A; Mazza, Carlos A; Dillon, Francisco M; Chludil, Hugo D; Ballaré, Carlos L

    2015-05-01

    Solar UV-B radiation (280-315 nm) has a significant influence on trophic relationships in natural and managed ecosystems, affecting plant-insect interactions. We explored the effects of ambient UV-B radiation on the levels of herbivory by stink bugs (Nezara viridula and Piezodorus guildinii) in field-grown soybean crops. The experiments included two levels of UV-B radiation (ambient and attenuated UV-B) and four soybean cultivars known to differ in their content of soluble leaf phenolics. Ambient UV-B radiation increased the accumulation of the isoflavonoids daidzin and genistin in the pods of all cultivars. Soybean crops grown under attenuated UV-B had higher numbers of unfilled pods and damaged seeds than crops grown under ambient UV-B radiation. Binary choice experiments with soybean branches demonstrated that stink bugs preferred branches of the attenuated UV-B treatment. We found a positive correlation between percentage of undamaged seeds and the contents of daidzin and genistin in pods. Our results suggest that constitutive and UV-B-induced isoflavonoids increase plant resistance to stink bugs under field conditions. © 2014 John Wiley & Sons Ltd.

  8. Highly transparent and UV-resistant superhydrophobic SiO2-coated ZnO nanorod arrays

    KAUST Repository

    Gao, Yangqin; Gereige, Issam; El Labban, Abdulrahman; Cha, Dong Kyu; Isimjan, Tayirjan T.; Beaujuge, Pierre

    2014-01-01

    Highly transparent and UV-resistant superhydrophobic arrays of SiO 2-coated ZnO nanorods are prepared in a sequence of low-temperature (<150 C) steps on both glass and thin sheets of PET (2 × 2 in. 2), and the superhydrophobic nanocomposite

  9. Isolation and molecular identification of a UV-resistant strain of Dietzia maris and antioxidant activity of pigment

    Directory of Open Access Journals (Sweden)

    Narges Zamanian

    2016-09-01

    Full Text Available Introduction: The ability of radioresistant bacteria to survive high levels of UV radiation has been linked to their strong DNA repair systems and ability to produce primary and secondary metabolic products. The biosynthesis of pigments provides an opportunity for bacteria to live in radiation-rich environment. Recent radiation-responsive pigments are used commercially as food colorants, anticancer drugs, as well as antibiotics and for cosmetic purposes. Materials and methods: Soil sample of Omidiyeh city was collected during the spring of 2014 and UV-resistant strain was isolated after primary and secondary screening. Then it was identified by molecular methods (16S rRNA gene sequencing. Antioxidant activity of pigment was evaluated by 2,2 -diphenyl-1-picryl hydrazyl (DPPH and the reducing power of pigments were analyzed by ferric chloride. Results: In this present study, new UV-resistant strain NM2 was isolated and by comparison of these 16S rRNA gene sequences to public database using the BLAST, the genus and species of the isolate was identified as Dietzia maris with 99% similarity. Extraction of pigment from isolated strain was carried out by methanol and acetone as solvents. The spectrum is characterized by maximum peak at 473 nm for pigment of NM2 strain. Antioxidant activity and the reducing ability of pigments increased by increasing their concentrations. NM2 strain pigment showed EC50 concentration of 3.30 mg/ml for DPPH free radical scavenging activity, and EC50 concentration of 28.46 µg/ml for reducing power. Discussion and conclusion: Isolation of natural resources of pigment is very important with high anti-oxidant activity. In the current study, pigment of UV-resistant bacteria demonstrated a strong antioxidant activity in vitro and pigment of these bacteria could play an important role in UV tolerance. Pigment of UV-resistant bacteria may be an appropriate source for antioxidative-related functional foods and the pharmaceutical

  10. Ectopic expression of ubiquitin-conjugating enzyme gene from wild rice, OgUBC1, confers resistance against UV-B radiation and Botrytis infection in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Jeon, En Hee; Pak, Jung Hun; Kim, Mi Jin; Kim, Hye Jeong; Shin, Sang Hyun; Lee, Jai Heon; Kim, Doh Hoon; Oh, Ju Sung; Oh, Boung-Jun; Jung, Ho Won; Chung, Young Soo

    2012-01-01

    Highlights: ► We isolated a novel E2 ubiquitin-conjugating enzyme from leaves of wild rice plants. ► The OgUBC1 was highly expressed in leaves treated with SA and UV-B radiation. ► The recombinant OgUBC1 has an enzymatic activity of E2 in vitro. ► The OgUBC1 could protect disruption of plant cells by UV-B radiation. ► OgUBC1 confers disease resistance and UV-B tolerance in transgenic Arabidopsis plants. -- Abstract: A previously unidentified gene encoding ubiquitin-conjugating enzyme was isolated from leaves of wild rice plant treated with wounding and microbe-associated molecular patterns. The OgUBC1 gene was composed of 148 amino acids and contained a typical active site and 21 ubiquitin thioester intermediate interaction residues and 4 E3 interaction residues. Both exogenous application of salicylic acid and UV-B irradiation triggered expression of OgUBC1 in leaves of wild rice. Recombinant OgUBC1 proteins bound to ubiquitins in vitro, proposing that the protein might act as E2 enzyme in planta. Heterologous expression of the OgUBC1 in Arabidopsis thaliana protected plants from cellular damage caused by an excess of UV-B radiation. A stable expression of chalcone synthase gene was detected in leaves of OgUBC1-expressing Arabidopsis, resulting in producing higher amounts of anthocyanin than those in wild-type Col-0 plants. Additionally, both pathogenesis-related gene1 and 5 were transcribed in the transgenic Arabidopsis in the absence of pathogen infection. The OgUBC1-expressing plants were resistant to the infection of Botrytis cinerea. Taken together, we suggested that the OgUBC1 is involved in ubiquitination process important for cellular response against biotic and abiotic stresses in plants.

  11. Ectopic expression of ubiquitin-conjugating enzyme gene from wild rice, OgUBC1, confers resistance against UV-B radiation and Botrytis infection in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, En Hee; Pak, Jung Hun; Kim, Mi Jin; Kim, Hye Jeong [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of); Shin, Sang Hyun [National Crop Experiment Station, Rural Development Administration, Suwon 441-100 (Korea, Republic of); Lee, Jai Heon; Kim, Doh Hoon; Oh, Ju Sung [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of); Oh, Boung-Jun [BioControl Center, Jeonnam 516-942 (Korea, Republic of); Jung, Ho Won, E-mail: hwjung@dau.ac.kr [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of); Chung, Young Soo, E-mail: chungys@dau.ac.kr [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer We isolated a novel E2 ubiquitin-conjugating enzyme from leaves of wild rice plants. Black-Right-Pointing-Pointer The OgUBC1 was highly expressed in leaves treated with SA and UV-B radiation. Black-Right-Pointing-Pointer The recombinant OgUBC1 has an enzymatic activity of E2 in vitro. Black-Right-Pointing-Pointer The OgUBC1 could protect disruption of plant cells by UV-B radiation. Black-Right-Pointing-Pointer OgUBC1 confers disease resistance and UV-B tolerance in transgenic Arabidopsis plants. -- Abstract: A previously unidentified gene encoding ubiquitin-conjugating enzyme was isolated from leaves of wild rice plant treated with wounding and microbe-associated molecular patterns. The OgUBC1 gene was composed of 148 amino acids and contained a typical active site and 21 ubiquitin thioester intermediate interaction residues and 4 E3 interaction residues. Both exogenous application of salicylic acid and UV-B irradiation triggered expression of OgUBC1 in leaves of wild rice. Recombinant OgUBC1 proteins bound to ubiquitins in vitro, proposing that the protein might act as E2 enzyme in planta. Heterologous expression of the OgUBC1 in Arabidopsis thaliana protected plants from cellular damage caused by an excess of UV-B radiation. A stable expression of chalcone synthase gene was detected in leaves of OgUBC1-expressing Arabidopsis, resulting in producing higher amounts of anthocyanin than those in wild-type Col-0 plants. Additionally, both pathogenesis-related gene1 and 5 were transcribed in the transgenic Arabidopsis in the absence of pathogen infection. The OgUBC1-expressing plants were resistant to the infection of Botrytis cinerea. Taken together, we suggested that the OgUBC1 is involved in ubiquitination process important for cellular response against biotic and abiotic stresses in plants.

  12. Multiple Roles for UV RESISTANCE LOCUS8 in Regulating Gene Expression and Metabolite Accumulation in Arabidopsis under Solar Ultraviolet Radiation1[W][OA

    Science.gov (United States)

    Morales, Luis O.; Brosché, Mikael; Vainonen, Julia; Jenkins, Gareth I.; Wargent, Jason J.; Sipari, Nina; Strid, Åke; Lindfors, Anders V.; Tegelberg, Riitta; Aphalo, Pedro J.

    2013-01-01

    Photomorphogenic responses triggered by low fluence rates of ultraviolet B radiation (UV-B; 280–315 nm) are mediated by the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8). Beyond our understanding of the molecular mechanisms of UV-B perception by UVR8, there is still limited information on how the UVR8 pathway functions under natural sunlight. Here, wild-type Arabidopsis (Arabidopsis thaliana) and the uvr8-2 mutant were used in an experiment outdoors where UV-A (315–400 nm) and UV-B irradiances were attenuated using plastic films. Gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation, and leaf metabolite signatures were analyzed. The results show that UVR8 is required for transcript accumulation of genes involved in UV protection, oxidative stress, hormone signal transduction, and defense against herbivores under solar UV. Under natural UV-A irradiance, UVR8 is likely to interact with UV-A/blue light signaling pathways to moderate UV-B-driven transcript and PDX1 accumulation. UVR8 both positively and negatively affects UV-A-regulated gene expression and metabolite accumulation but is required for the UV-B induction of phenolics. Moreover, UVR8-dependent UV-B acclimation during the early stages of plant development may enhance normal growth under long-term exposure to solar UV. PMID:23250626

  13. Heat, hydrogen peroxide, and UV resistance of Bacillus subtilis spores with increased core water content and with or without major DNA-binding proteins

    International Nuclear Information System (INIS)

    Popham, D.L.; Sengupta, S.; Setlow, P.

    1995-01-01

    Spores of a Bacillus subtilis strain with an insertion mutation in the dacB gene, which codes for an enzyme involved in spore cortex biosynthesis, have a higher core water content than wild-type spores. Spores lacking the two major α/β-type small, acid-soluble proteins (SASP) (termed a α - β - spores) have the same core water content as do wild-type spores, but α - β - dacB spores had more core water than did dacB spores. The resistance of α - β - , α - β - dacB, dacB, and wild-type spores to dry and moist heat, hydrogen peroxide, and UV radiation has been determined, as has the role of DNA damage in spore killing by moist heat and hydrogen peroxide. These data (1) suggest that core water content has little if any role in spore UV resistance and are consistent with binding of α/β-type SASP to DNA being the major mechanism providing protection to spores from UV radiation; (2) suggest that binding of αβ-type SASP to DNA is the major mechanism unique to spores providing protection from dry heat; (3) suggest that spore resistance to moist heat and hydrogen peroxide is affected to a large degree by the core water content, as increased core water resulted in large decreases in spore resistance to these agents; and (4) indicate that since this decreased resistance (i.e., in dacB spores) is not associated with increased spore killing by DNA damage, spore DNA must normally be extremely well protected against such damage, presumably by the saturation of spore DNA by α/β-type SASP. 19 refs., 2 figs., 5 tabs

  14. UV Enhanced Oxygen Response Resistance Ratio of ZnO Prepared by Thermally Oxidized Zn on Sapphire Substrate

    Directory of Open Access Journals (Sweden)

    Cheng-Chang Yu

    2013-01-01

    Full Text Available ZnO thin film was fabricated by thermally oxidized Zn at 600°C for 1 h. A surface containing nanostructured dumbbell and lines was observed by scanning electron microscope (SEM. The ZnO resistor device was formed after the following Ti/Au metallization. The device resistance was characterized at different oxygen pressure environment in the dark and under ultraviolet (UV light illumination coming from the mercury lamp with a short pass filter. The resistance increases with the increase of oxygen pressure. The resistance decreases and response increases with the increase of light intensity. Models considering the barrier height variation caused by the adsorbed oxygen related species were used to explain these results. The UV light illumination technology shows an effective method to enhance the detection response for this ZnO resistor oxygen sensor.

  15. RecA-independent resistance to irradiation with u.v. light in acid-habituated Escherichia coli

    International Nuclear Information System (INIS)

    Goodson, M.; Rowbury, R.J.

    1991-01-01

    Growth of Escherichia coli 1829 ColV, I-K94 at pH 5.0 led to an increase in u.v. resistance compared with cells grown at pH 7.0. This was due to a phenotypic change, since organisms grown at pH 7.0 showed increased resistance after only 2.5-5.0 min incubation at the mildly acid pH. Other E. coli K12 derivatives became more u.v.-resistant at pH 5.0 including uvrA, recA and polAl mutants. Organisms grown at pH 5.0 also showed increased Weigle reactivation of u.v. irradiated λ phage and this applied to the repair-deficient mutants as well as the parent strains. Both the increased u.v. resistance of acid-habituated cells and their increased ability to bring about Weigle reactivation appear to involve RecA-independent processes and are presumably, therefore, independent of the SOS response. (author)

  16. Repair-deficient xeroderma pigmentosum cells made UV light resistant by fusion with X-ray-inactivated Chinese hamster cells

    International Nuclear Information System (INIS)

    Karentz, D.; Cleaver, J.E.

    1986-01-01

    Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The hybrid cells exhibited UV resistance and DNA repair characteristics comparable to those expressed by CHO cells, and their DNA had greater homology with CHO DNA than did the DNA from XP cells. Control experiments consisted of fusion of irradiated and unirradiated XP cells and repeated exposure of unfused XP cells to UV doses used for hybrid selection. These treatments did not result in an increase in UV resistance, repair capability, or homology with CHO DNA. The hybrid cell lines do not, therefore, appear to be XP revertants. The establishment of these stable hybrid cell lines is an initial step toward identifying and cloning CHO DNA repair genes that complement the XP defect in human cells. The method should also be applicable to cloning genes for other diseases, such as ataxia-telangiectasia and Fanconi's anemia

  17. Molecular Cloning and Functional Analysis of UV RESISTANCE LOCUS 8 (PeUVR8 from Populus euphratica.

    Directory of Open Access Journals (Sweden)

    Ke Mao

    Full Text Available Ultraviolet-B (UV-B; 280-315 nm light, which is an integral part of the solar radiation reaching the surface of the Earth, induces a broad range of physiological responses in plants. The UV RESISTANCE LOCUS 8 (UVR8 protein is the first and only light photoreceptor characterized to date that is specific for UV-B light and it regulates various aspects of plant growth and development in response to UV-B light. Despite its involvement in the control of important plant traits, most studies on UV-B photoreceptors have focused on Arabidopsis and no data on UVR8 function are available for forest trees. In this study, we isolated a homologue of the UV receptor UVR8 of Arabidopsis, PeUVR8, from Populus euphratica (Euphrates poplar and analyzed its structure and function in detail. The deduced PeUVR8 amino acid sequence contained nine well-conserved regulator of chromosome condensation 1 (RCC1 repeats and the region 27 amino acids from the C terminus (C27 that interact with COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC1. Secondary and tertiary structure analysis showed that PeUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis thaliana. Using heterologous expression in Arabidopsis, we showed that PeUVR8 overexpression rescued the uvr8 mutant phenotype. In addition, PeUVR8 overexpression in wild-type background seedlings grown under UV-B light inhibited hypocotyl elongation and enhanced anthocyanin accumulation. Furthermore, we examined the interaction between PeUVR8 and AtCOP1 using a bimolecular fluorescence complementation (BiFC assay. Our data provide evidence that PeUVR8 plays important roles in the control of photomorphogenesis in planta.

  18. Influence of dimethyl dicarbonate on the resistance of Escherichia coli to a combined UV-Heat treatment in apple juice

    Science.gov (United States)

    Gouma, Maria; Gayán, Elisa; Raso, Javier; Condón, Santiago; Álvarez, Ignacio

    2015-01-01

    Commercial apple juice inoculated with Escherichia coli was treated with UV-C, heat (55°C) and dimethyl dicarbonate – DMDC (25, 50, and 75 mg/L)-, applied separately and in combination, in order to investigate the possibility of synergistic lethal effects. The inactivation levels resulting from each treatment applied individually for a maximum treatment time of 3.58 min were limited, reaching 1.2, 2.9, and 0.06 log10 reductions for UV, heat, and DMDC (75 mg/L), respectively. However, all the investigated combinations resulted in a synergistic lethal effect, reducing the total treatment time and UV dose, with the synergistic lethal effect being higher when larger concentrations of DMDC were added to the apple juice. The addition of 75 mg/L of DMDC prior to the combined UV-C light treatment at 55°C resulted in 5 log10 reductions after only 1.8 min, reducing the treatment time and UV dose of the combined UV-Heat treatment by 44%. PMID:26042117

  19. Academic Conferences: Representative and Resistant Sites for Higher Education Research

    Science.gov (United States)

    Henderson, Emily F.

    2015-01-01

    The overarching argument made in this article is twofold. Firstly, academic conferences are posited as sites for higher education research. Secondly, the well-recognised emotional and social processes of conferences are used to make space at the boundaries of higher education research for psychosocial analysis. The article theorises conferences in…

  20. An oxygen-insensitive degradable resist for fabricating metallic patterns on highly curved surfaces by UV-nanoimprint lithography.

    Science.gov (United States)

    Hu, Xin; Huang, Shisong; Gu, Ronghua; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng

    2014-10-01

    In this paper, an oxygen-insensitive degradable resist for UV-nanoimprint is designed, com-prising a polycyclic degradable acrylate monomer, 2,10-diacryloyloxymethyl-1,4,9,12-tetraoxa-spiro [4.2.4.2] tetradecane (DAMTT), and a multifunctional thiol monomer pentaerythritol tetra(3-mercaptopropionate) (PETMP). The resist can be quickly UV-cured in the air atmosphere and achieve a high monomer conversion of over 98%, which greatly reduce the adhesion force between the resist and the soft mold. High conversion, in company with an adequate Young's modulus (about 1 GPa) and an extremely low shrinkage (1.34%), promises high nanoimprint resolution of sub-50 nm. The cross-linked resist is able to break into linear molecules in a hot acid solvent. As a result, metallic patterns are fabricated on highly curved surfaces via the lift off process without the assistance of a thermoplastic polymer layer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Induction of UV-resistant DNA replication in Escherichia coli: Induced stable DNA replication as an SOS function

    International Nuclear Information System (INIS)

    Kogoma, T.; Torrey, T.A.; Connaughton, M.J.

    1979-01-01

    The striking similarity between the treatments that induce SOS functions and those that result in stable DNA replication (continuous DNA replication in the absence of protein synthesis) prompted us to examine the possibility of stable DNA replication being a recA + lexA + -dependent SOS function. In addition to the treatments previously reported, ultraviolet (UV) irradiation or treatment with mitomycin C was also found to induce stable DNA replication. The thermal treatment of tif-1 strains did not result in detectable levels of stable DNA replication, but nalidixic acid readily induced the activity in these strains. The induction of stable DNA replication with nalidixic acid was severely suppressed in tif-1 lex A mutant strains. The inhibitory activity of lexA3 was negated by the presence of the spr-5l mutation, an intragenic suppressor of lexA3. Induced stable DNA replication was found to be considerably more resistant to UV irradiation than normal replication both in a uvr A6 strain and a uvr + strain. The UV-resistant replication occurred mostly in the semiconservative manner. The possible roles of stable DNA replication in repair of damaged DNA are discussed. (orig.)

  2. Association of mutator activity with UV sensitivity in an aphidicolin-resistant mutant of Chinese hamster V79 cells

    International Nuclear Information System (INIS)

    Liu, P.K.; Chang, C.; Trosko, J.E.

    1982-01-01

    The spontaneous mutation rates of an ultraviolet light (UV)-sensitive aphidicolin-resistant mutant (aphsup(r)-4-2) and its revertants have been determined by 2 techniques. By using the fluctuation analysis, the mutant and its thymidine (TdR)-prototrophic 'revertant' were found to exhibit elevated spontaneous mutation rates at the 6-thioguanine- and diphtheria-toxin-resistant loci. In contrast, the TdR-auxotrophic 'revertant' did not show this property. Similar results were obtained by the multiple replating technique. From these comparative studies and other previous characterizations, it appears that a single gene mutation is responsible for the following pleiotropic phenotype: slow growth, UV sensitivity, high UV-induced mutability, high frequency of site-specific bromodeoxyuridine (BrdU)-dependent chromosome breaks and enhanced spontaneous mutation rate. Recent studies indicate that the mutation may be on the gene for DNA polymerase α. The results further indicate that thymidine auxotrophy or imbalance in nucleotide pools is not necessarily associated with the mutator activity in mammalian cells. (orig.)

  3. H2O2 and/or TiO2 photocatalysis under UV irradiation for the removal of antibiotic resistant bacteria and their antibiotic resistance genes

    International Nuclear Information System (INIS)

    Guo, Changsheng; Wang, Kai; Hou, Song; Wan, Li; Lv, Jiapei; Zhang, Yuan; Qu, Xiaodong; Chen, Shuyi; Xu, Jian

    2017-01-01

    Highlights: • TiO 2 thin film was successfully synthesized for treating ARB and ARGs from water. • More than 5.5 log units of ARB reduction was achieved by TiO 2 under UV irradiation. • With TiO 2 , ARGs were reduced by more than 5 log units under UV irradiation. • TiO 2 could remove both intracellular and extracellular forms of ARGs. - Abstract: Inactivating antibiotic resistant bacteria (ARB) and removing antibiotic resistance genes (ARGs) are very important to prevent their spread into the environment. Previous efforts have been taken to eliminate ARB and ARGs from aqueous solution and sludges, however, few satisfying results have been obtained. This study investigated whether photocatalysis by TiO 2 was able to reduce the two ARGs, mecA and ampC, within the host ARB, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. The addition of H 2 O 2 and matrix effect on the removal of ARB and ARGs were also studied. TiO 2 thin films showed great effect on both ARB inactivation and ARGs removal. Approximately 4.5-5.0 and 5.5–5.8 log ARB reductions were achieved by TiO 2 under 6 and 12 mJ/cm 2 UV 254 fluence dose, respectively. For ARGs, 5.8 log mecA reduction and 4.7 log ampC reduction were achieved under 120 mJ/cm 2 UV 254 fluence dose in the presence of TiO 2 . Increasing dosage of H 2 O 2 enhanced the removal efficiencies of ARB and ARGs. The results also demonstrated that photocatalysis by TiO 2 was capable of removing both intracellular and extracellular forms of ARGs. This study provided a potential alternative method for the removal of ARB and ARGs from aqueous solution.

  4. Alfalfa seedlings grown outdoors are more resistant to UV-induced DNA damage than plants grown in a UV-free environmental chamber

    International Nuclear Information System (INIS)

    Takayanagi, Shinnosuke; Trunk, J.G.; Sutherland, J.C.; Sutherland, B.M.

    1994-01-01

    The relative UV sensitivities of alfalfa seedlings grown outdoors versus plants grown in a growth chamber under UV-filtered cool white fluorescent bulbs have been determined using three criteria: (1) level of endogenous DNA damage as sites for the UV endonuclease from Micrococcus luteus, (2) susceptibility to pyrimidine dimer induction by a UV challenge exposure and (3) ability to repair UV-induced damage. We find that outdoor-grown plants contain approximately equal frequencies of endogenous DNA damages, are less susceptible to dimer induction by a challenge exposure of broad-spectrum UV and photorepair dimers more rapidly than plants grown in an environmental chamber under cool white fluorescent lamps plus a filter removes most UV radiation. These data suggest that plants grown in a natural environment would be less sensitive to UVB-induced damage than would be predicted on the basis of studies on plants grown under minimum UV. (author)

  5. Higher pressure periodic CO/sub 2/ laser with non-self-sustaining discharge and UV ionization

    Energy Technology Data Exchange (ETDEWEB)

    Muratov, E A; Pismennyi, V D; Rakhimov, A T

    1979-02-01

    Stimulated emission was achieved in a CO/sub 2/ laser operating at 250 torr excited by a periodic non-self-sustaining discharge controlled by a spark source of UV radiation. Use of a UV source operating in periodic pulse regime is shown to permit quasicontinuous operation of the laser with characteristic radiating times up to several hundred microseconds.

  6. Absence of transient elevated uv resistance during germination of Bacillus subtilis spores lacking small, acid-soluble spore proteins α and β

    International Nuclear Information System (INIS)

    Setlow, B.; Setlow, P.

    1988-01-01

    Dormant spores of various Bacillus species are much more resistant to UV irradiation than are the corresponding vegetative cells. This elevated spore UV resistance appears to have two causes. First, UV irradiation of spores does not produce the pyrimidine dimers formed in vegetative-cell DNA, but rather produces several other photoproducts, the most predominant of which is termed the spore photoproduct, a 5-thyminyl-5,6-dihydrothymine adduct (1, 10). Second, spores have at least two mechanisms which efficiently repair this spore photoproduct during spore germination, including one which monomerizes the adduct back to two thymines. This study shows that germinating spores of bacillus subtilis mutants which lack small, acid-soluble spore proteins α and β did not exhibit the transient elevated UV resistance seen during germination of wild-type spores

  7. UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

    Directory of Open Access Journals (Sweden)

    Paul W. Barnes

    2017-08-01

    Full Text Available Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV-B (280–315 nm radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8 and non-native (mean = 5.8%; n = 11 species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees were represented solely by native species whereas herbaceous growth forms (grasses and forbs were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2% and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3% and did not vary with elevation in the native

  8. The IR obstruction to UV completion for Dante’s Inferno model with higher-dimensional gauge theory origin

    Energy Technology Data Exchange (ETDEWEB)

    Furuuchi, Kazuyuki [Manipal Centre for Natural Sciences, Manipal University,Manipal, Karnataka 576104 (India); Koyama, Yoji [National Center for Theoretical Sciences, National Tsing-Hua University,Hsinchu 30013, Taiwan R.O.C. (China)

    2016-06-21

    We continue our investigation of large field inflation models obtained from higher-dimensional gauge theories, initiated in our previous study http://dx.doi.org/10.1088/1475-7516/2015/02/031. We focus on Dante’s Inferno model which was the most preferred model in our previous analysis. We point out the relevance of the IR obstruction to UV completion, which constrains the form of the potential of the massive vector field, under the current observational upper bound on the tensor to scalar ratio. We also show that in simple examples of the potential arising from DBI action of a D5-brane and that of an NS5-brane that the inflation takes place in the field range which is within the convergence radius of the Taylor expansion. This is in contrast to the well known examples of axion monodromy inflation where inflaton takes place outside the convergence radius of the Taylor expansion. This difference arises from the very essence of Dante’s Inferno model that the effective inflaton potential is stretched in the inflaton field direction compared with the potential for the original field.

  9. Impacts of UV radiation and photomodification on the toxicity of PAHs to the higher plant Lemna gibba (duckweed)

    International Nuclear Information System (INIS)

    Huang, X.D.; Dixon, D.G.; Greenberg, B.M.

    1993-01-01

    The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive π-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activate the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene > phenanthrene > benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid (half-lives in hours), and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated

  10. The IR obstruction to UV completion for Dante’s Inferno model with higher-dimensional gauge theory origin

    International Nuclear Information System (INIS)

    Furuuchi, Kazuyuki; Koyama, Yoji

    2016-01-01

    We continue our investigation of large field inflation models obtained from higher-dimensional gauge theories, initiated in our previous study http://dx.doi.org/10.1088/1475-7516/2015/02/031. We focus on Dante’s Inferno model which was the most preferred model in our previous analysis. We point out the relevance of the IR obstruction to UV completion, which constrains the form of the potential of the massive vector field, under the current observational upper bound on the tensor to scalar ratio. We also show that in simple examples of the potential arising from DBI action of a D5-brane and that of an NS5-brane that the inflation takes place in the field range which is within the convergence radius of the Taylor expansion. This is in contrast to the well known examples of axion monodromy inflation where inflaton takes place outside the convergence radius of the Taylor expansion. This difference arises from the very essence of Dante’s Inferno model that the effective inflaton potential is stretched in the inflaton field direction compared with the potential for the original field.

  11. Building unique surface structure on aramid fibers through a green layer-by-layer self-assembly technique to develop new high performance fibers with greatly improved surface activity, thermal resistance, mechanical properties and UV resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Lifang; Yuan, Li; Guan, Qingbao; Gu, Aijuan, E-mail: ajgu@suda.edu.cn; Liang, Guozheng, E-mail: lgzheng@suda.edu.cn

    2017-07-31

    Highlights: • A green technology is setup to build unique surface structure on aramid fiber (AF). • The method is layer-by-layer self-assembling SiO{sub 2} and layered double hydroxide. • The surface of AF is adjustable by controlling the self-assembly cycle number. • New AF has excellent surface activity, anti-UV, thermal and mechanical properties. • The origin behind attractive performances of new AFs was intensively studied. - Abstract: Combining green preparation and high performance is becoming the direction of sustainable development of materials. How to simultaneously overcome the two bottlenecks (poor surface activity and UV resistance) of aramid fibers (AFs) while improving thermal and mechanical properties through a green process is still an interesting issue with big challenge. Herein, new AFs (BL-AFs) were prepared by alternately self-assembling SiO{sub 2} and MgAlFe layered double hydroxide (LDH) on surfaces of AFs, successively, through a green layer-by-layer (LBL) self-assembly technique without using high temperature and organic solvent. The structures and properties of BL-AFs were systematically studied, which are controllable by adjusting the number of self-assembly cycle. The new fibers with three or more self-assembly cycles have remarkably improved surface activity, thermal resistance, mechanical properties and UV resistance compared with AFs. Typically, with three self-assembly cycles, the initial degradation temperature and char yield of the new fiber (3BL-AF) are as high as 552.9 °C and 81.2%, about 92 °C and 25.2% higher than those of AF, respectively; after 168 h-UV irradiation, the retention of tensile performances of 3BL-AF fiber is as high as 91–95%, about 29–14% higher than that of AF, showing the best overall performances among all modified AFs prepared using a green technique reported so far. The origin behind the attractive performances of BL-AFs is revealed through correlating with structures of original and

  12. Highly transparent and UV-resistant superhydrophobic SiO2-coated ZnO nanorod arrays

    KAUST Repository

    Gao, Yangqin

    2014-02-26

    Highly transparent and UV-resistant superhydrophobic arrays of SiO 2-coated ZnO nanorods are prepared in a sequence of low-temperature (<150 C) steps on both glass and thin sheets of PET (2 × 2 in. 2), and the superhydrophobic nanocomposite is shown to have minimal impact on solar cell device performance under AM1.5G illumination. Flexible plastics can serve as front cell and backing materials in the manufacture of flexible displays and solar cells. © 2014 American Chemical Society.

  13. A herbicide-resistant ACCase 1781 Setaria mutant shows higher fitness than wild type.

    Science.gov (United States)

    Wang, T; Picard, J C; Tian, X; Darmency, H

    2010-10-01

    It is often alleged that mutations conferring herbicide resistance have a negative impact on plant fitness. A mutant ACCase1781 allele endowing resistance to the sethoxydim herbicide was introgressed from a resistant green foxtail (Setaria viridis (L.) Beauv) population into foxtail millet (S. italica (L.) Beauv.). (1) Better and earlier growth of resistant plants was observed in a greenhouse cabinet. (2) Resistant plants of the advanced BC7 backcross generation showed more vigorous juvenile growth in the field, earlier flowering, more tillers and higher numbers of grains than susceptible plants did, especially when both genotypes were grown in mixture, but their seeds were lighter than susceptible seeds. (3) Field populations originating from segregating hybrids had the expected allele frequencies under normal growth conditions, but showed a genotype shift toward an excess of homozygous resistant plants within 3 years in stressful conditions. Lower seed size, lower germination rate and perhaps unexplored differences in seed longevity and predation could explain how the resistant plants have the same field fitness over the whole life cycle as the susceptible ones although they produce more seeds. More rapid growth kinetics probably accounted for higher fitness of the resistant plants in adverse conditions. The likelihood of a linkage with a beneficial gene is discussed versus the hypothesis of a pleiotropic effect of the ACCase resistance allele. It is suggested that autogamous species like Setaria could not develop a resistant population without the help of a linkage with a gene producing a higher fitness.

  14. Enhanced repair of cyclobutane pyrimidine dimers and improved UV resistance in photolyase transgenic mice

    NARCIS (Netherlands)

    W. Schul; J. Jans (Judith); Y.M. Rijksen (Yvonne); K.H. Klemann; J. de Wit (Jan); O. Nikaido; S. Nakajima; A. Yasui (Akira); J.H.J. Hoeijmakers (Jan); G.T.J. van der Horst (Gijsbertus); A.P.M. Eker (André)

    2002-01-01

    textabstractDuring evolution, placental mammals appear to have lost cyclobutane pyrimidine dimer (CPD) photolyase, an enzyme that efficiently removes UV-induced CPDs from DNA in a light-dependent manner. As a consequence, they have to rely solely on the more complex, and for this lesion less

  15. Immobilized WO3 nanoparticles on graphene oxide as a photo-induced antibacterial agent against UV-resistant Bacillus pumilus

    Science.gov (United States)

    Hosseini, Farshad; Rasuli, Reza; Jafarian, Vahab

    2018-04-01

    We present the antibacterial and photo-catalytic activity of immobilized WO3 nanoparticles on graphene oxide sheets. WO3 nanoparticles were immobilized on graphene oxide using the arc discharge method in arc currents of 5, 20, 40 and 60 A. Tauc plots of the UV-visible spectra show that the band gap of the prepared samples decreases (to ~2.7 eV) with respect to the WO3 nanoparticles. Photo-catalytic activity was examined by the degradation of rhodamine B under ultra-violet irradiation and the results show that the photo-catalytic activity of WO3 nanoparticles is increased by immobilizing them on graphene oxide sheets. In addition, the photo-degradation yield of the samples prepared by the 5 A arc current is 84% in 120 min, which is more than that of the other samples. The antibacterial activity of the prepared samples was studied against Bacillus pumilus (B. pumilus) bacteria, showing high resistance to ultra-violet exposure. Our results show that the bare and immobilized WO3 nanoparticles become more active under UV irradiation and their antibacterial properties are comparable with Ag nanoparticles. Besides this, the results show that although the photo-catalytic activity of the post-annealed samples at 500 °C is less than the as-prepared samples, it is, however, more active against B. pumilus bacteria under UV irradiation.

  16. Simultaneous analysis of residual stress and stress intensity factor in a resist after UV-nanoimprint lithography based on electron moiré fringes

    International Nuclear Information System (INIS)

    Wang, Qinghua; Kishimoto, Satoshi

    2012-01-01

    In this study, the residual stress in a resist (PAK01) film and the stress intensity factor (SIF) of an induced crack are simultaneously estimated during ultraviolet nanoimprint lithography (UV-NIL) based on electron moiré fringes. A micro grid in a triangular arrangement on the resist film fabricated by UV-NIL is directly used as the model grid. Electron moiré fringes formed by the interference between the fabricated grid and the electron scan beam are used to measure the displacement distribution around the tip of a crack induced by the residual stress in the resist. The SIF of the crack is estimated using a displacement extrapolation method. The residual strain fields and the corresponding residual stress in the resist film far from the crack are determined and analyzed. This method is effective for evaluating the grid quality fabricated by the UV-NIL technique. (paper)

  17. Investigation of γ-(2,3-Epoxypropoxypropyltrimethoxy Silane Surface Modified Layered Double Hydroxides Improving UV Ageing Resistance of Asphalt

    Directory of Open Access Journals (Sweden)

    Canlin Zhang

    2017-01-01

    Full Text Available γ-(2,3-Epoxypropoxypropyltrimethoxy silane surface modified layered double hydroxides (KH560-LDHs were prepared and used to improve the ultraviolet ageing resistance of asphalt. The results of X-ray photoelectron spectrometry (XPS indicated that KH560 has been successfully grafted onto the surface of LDHs. The agglomeration of LDHs particles notably reduced after KH560 surface modification according to scanning electron microscopy (SEM, which implied that the KH560 surface modification was helpful to promote the dispersibility of LDHs in asphalt. Then, the influence of KH560-LDHs and LDHs on the physical and rheological properties of asphalt before and after UV ageing was thoroughly investigated. The storage stability test showed that the difference in softening point (ΔS of LDHs modified asphalt decreased from 0.6 °C to 0.2 °C at an LDHs content of 1% after KH560 surface modification, and the tendency became more pronounced with the increase of LDH content, indicating that KH560 surface modification could improve the stability of LDHs in asphalt. After UV ageing, the viscous modulus (G’’ of asphalt significantly reduced, and correspondingly, the elastic modulus (G’ and rutting factor (G*/sin δ rapidly increased. Moreover, the asphaltene increased and the amount of “bee-like” structures of the asphalt decreased. Compared with LDHs, KH560-LDHs obviously restrained performance deterioration of the asphalt, and helped to relieve the variation of the chemical compositions and morphology of asphalt, which suggested that the improvement of KH560-LDHs on UV ageing resistance of asphalt was superior to LDHs.

  18. Fabrication of Robust Super hydrophobic Bamboo Based on ZnO Nano sheet Networks with Improved Water-, UV-, and Fire-Resistant Properties

    International Nuclear Information System (INIS)

    Li, J.; Sun, Q.; Yao, Q.; Wang, J.; Han, Sh.; Jin, Ch.

    2014-01-01

    Bamboo with water-resistant, UV-resistant, and fire-resistant properties was desirable in modern society. In this paper, the original bamboo was firstly treated with ZnO sol and then hydrothermally the ZnO nano sheet networks grow onto the bamboo surface and subsequently modified with fluoro alkyl silane (FAS-17). The FAS-17 treated bamboo substrate exhibited not only robust super hydrophobicity with a high contact angle of 161° but also stable repellency towards simulated acid rain (ph = 3) with a contact angle of 152°. Except for its robust super hydrophobicity, such a bamboo also presents superior water-resistant, UV-resistant, and fire-resistant properties.

  19. Fabrication of Robust Superhydrophobic Bamboo Based on ZnO Nanosheet Networks with Improved Water-, UV-, and Fire-Resistant Properties

    Directory of Open Access Journals (Sweden)

    Jingpeng Li

    2015-01-01

    Full Text Available Bamboo with water-resistant, UV-resistant, and fire-resistant properties was desirable in modern society. In this paper, the original bamboo was firstly treated with ZnO sol and then hydrothermally the ZnO nanosheet networks grow onto the bamboo surface and subsequently modified with fluoroalkyl silane (FAS-17. The FAS-17 treated bamboo substrate exhibited not only robust superhydrophobicity with a high contact angle of 161° but also stable repellency towards simulated acid rain (pH = 3 with a contact angle of 152°. Except for its robust superhydrophobicity, such a bamboo also presents superior water-resistant, UV-resistant, and fire-resistant properties.

  20. Applicability of UV resistant Bacillus pumilus endospores as a human adenovirus surrogate for evaluating the effectiveness of virus inactivation in low-pressure UV treatment systems

    Science.gov (United States)

    Recent studies have demonstrated the potential to use Bacillus pumilus endospores as a surrogate of human adenovirus (HAdV) in UV disinfection studies. The use of endospores has been limited by observations of batch-to-batch variation in UV sensitivity. This study reports on a pr...

  1. Impact of UV and peracetic acid disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli in wastewater effluents.

    Science.gov (United States)

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke; Frigon, Dominic

    2014-06-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm(2) and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.

  2. Impact of UV and Peracetic Acid Disinfection on the Prevalence of Virulence and Antimicrobial Resistance Genes in Uropathogenic Escherichia coli in Wastewater Effluents

    Science.gov (United States)

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke

    2014-01-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2 and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters. PMID:24727265

  3. Study of the resistance mechanisms to ultraviolet radiation in Escherichia Coli. II. General characteristics of the mutants resistant to ultraviolet radiation of Escherichia Coli PQ30; Estudio de los mecanismos de resistencia a UV en E. coli. II. Caracteristicas generales de los mutantes resistentes a UV de E. coli PQ30

    Energy Technology Data Exchange (ETDEWEB)

    Alcantara D, D [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1995-12-15

    Inside this second work the results are shown on the preliminary characterization of the 5 populations of Escherichia coli that its were subjected to the light UV, by means of 80 irradiation- growth cycles, the dose of which it was duplicated each 10 cycles. The course that the resistance to UV to those 5 populations continued along the process, that covers some 165 generations, and the level reached at the end by each one of them suggests the presence of different resistance mechanisms to the UV light. (Author)

  4. Higher Desolvation Energy Reduces Molecular Recognition in Multi-Drug Resistant HIV-1 Protease

    Directory of Open Access Journals (Sweden)

    Ladislau C. Kovari

    2012-05-01

    Full Text Available Designing HIV-1 protease inhibitors that overcome drug-resistance is still a challenging task. In this study, four clinical isolates of multi-drug resistant HIV-1 proteases that exhibit resistance to all the US FDA-approved HIV-1 protease inhibitors and also reduce the substrate recognition ability were examined. A multi-drug resistant HIV-1 protease isolate, MDR 769, was co-crystallized with the p2/NC substrate and the mutated CA/p2 substrate, CA/p2 P1’F. Both substrates display different levels of molecular recognition by the wild-type and multi-drug resistant HIV-1 protease. From the crystal structures, only limited differences can be identified between the wild-type and multi-drug resistant protease. Therefore, a wild-type HIV-1 protease and four multi-drug resistant HIV-1 proteases in complex with the two peptides were modeled based on the crystal structures and examined during a 10 ns-molecular dynamics simulation. The simulation results reveal that the multi-drug resistant HIV-1 proteases require higher desolvation energy to form complexes with the peptides. This result suggests that the desolvation of the HIV-1 protease active site is an important step of protease-ligand complex formation as well as drug resistance. Therefore, desolvation energy could be considered as a parameter in the evaluation of future HIV-1 protease inhibitor candidates.

  5. α6 Integrin and CD44 enrich for a primary keratinocyte population that displays resistance to UV-induced apoptosis.

    Directory of Open Access Journals (Sweden)

    Helen Wray

    Full Text Available Epidermal human keratinocytes are exposed to a wide range of environmental genotoxic insults, including the UV component of solar radiation. Epidermal homeostasis in response to cellular or tissue damage is maintained by a population of keratinocyte stem cells (KSC that reside in the basal layer of the epithelium. Using cell sorting based on cell-surface markers, we have identified a novel α6 integrin(high+/CD44(+ sub-population of basal keratinocytes. These α6 integrin(high+/CD44(+ keratinocytes have both high proliferative potential, form colonies in culture that have characteristics of holoclones and have a unique pattern of resistance to apoptosis induced by UVB radiation or by agents that induce single- or double strand DNA breaks. Resistance to UVB induced apoptosis in the α6 integrin(high+/CD44(+ cells involved increased expression of TAp63 and was overcome by PI-3 kinase inhibition. In marked contrast, the α6 integrin(high+/CD44(+ cells were sensitive to apoptosis induced by the cross-linking agent cisplatin, and imatinib inhibition of c-Abl blocked the ability of cisplatin to kill α6 integrin(high+/CD44(+ cells. Our findings reveal a population of basal keratinocytes with long-term proliferative properties that display specific patterns of apoptotic resistance that is dependent upon the genotoxic stimulus, and provide insights into how these cells can be targeted with chemotherapeutic agents.

  6. Study the scratch resistance of UV-cured epoxy acrylate in the presence of nano alumina particles via nano indentation

    International Nuclear Information System (INIS)

    Bastani, S.; Ebrahimi, M.; Kardar, P.

    2007-01-01

    In this research, an epoxy acrylate resin was synthesized, then the synthesized resin was used along with different multifunctional acrylate monomers and with a photoinitiator in different formulations and cured with UV radiation. The experiments were designed based on mixture method by using Design-Expert software. To investigate the effect of nano particles on the some of physical and mechanical properties of the UV cured resins, the suspension of nano alumina in TPGDA, was used in formulations. The hardness of prepared films was evaluated by using konig hardness tester and nano indentater. The scratch resistance and gloss of the films were also determined. The results showed that the visibility of scratch decreased when the nano particles were used. It seems that the self-healing property of the film improved in the presence of nano particles. The hardness of the samples with nano particles was found to be less than that the samples of without any nano particles. It was observed that the gloss of the films with the nano particles, almost was the same as the film without nano particles. (Author)

  7. Applicability of UV resistant Bacillus pumilus spore as a human adenovirus surrogate for evaluating the effectiveness of virus inactivation in low-pressure UV treatment systems

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data set includes UV dose, and Bacillus pumilus spore plate counts in colony forming units. This dataset is associated with the following publication: Boczek , L.,...

  8. Fabrication of optical waveguides by imprinting: usage of positive tone resist as a mould for UV-curable polymer.

    Science.gov (United States)

    Hiltunen, Jussi; Hiltunen, Marianne; Puustinen, Jarkko; Lappalainen, Jyrki; Karioja, Pentti

    2009-12-07

    Optical ridge type waveguides based on UV-curable polymer were fabricated by imprinting method. Positive tone resist patterned on a silicon wafer was used as a mould. The characterization of waveguides was carried out by coupling TE-polarized light from a tapered fiber into a waveguide with 30 mm length and mapping the intensity distribution with another tapered fiber at the output facet of a waveguide. Proper single- or multimode operation was observed depending on the waveguide width being either 2 microm or 6 microm. Experimental observations on the mode profiles were also supported by the simulation results. Average power transmissions of 32% at 1530 nm wavelength and 45% at 1310 nm wavelength were characterized. The results suggest that the simple mould fabrication process might be a useful technique for device prototyping and that the performance of replicated waveguides can meet the requirements for certain applications.

  9. Electroless plating Cu-Co-P polyalloy on UV/ozonolysis irradiated polyethylene terephthalate film and its corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Lei; Bi, Siyi; Zhao, Hang; Xu, Yumeng; Mu, Yuhang; Lu, Yinxiang, E-mail: yxlu@fudan.edu.cn

    2017-05-01

    Highlights: • Electroless plating Cu-Co-P polyalloy was firstly fabricated onto polyethylene terephthalate (PET) substrate. • An etchant-free and amine-free UV/ozonolysis irradiation method UV/ozonolysis was effective for the transition from hydrophilic to hydrophobic of PET sheet. • A time-saving and cost-effective orthogonal experiment (L{sub 9}(3){sup 4}) was utilized to optimize the plating conditions. • The optimized copper polyalloy possessed high corrosion resistance in three aggressive mediums including NaCl, NaOH and HCl, respectively. • The Cu-Co-P coated PET composite showed excellent electromagnetic interference shielding effectiveness (EMI SE > 99.999% at frequency ranging from 30 MHz to 1000 MHz). - Abstract: High corrosion resistant Cu-Co-P coatings were firstly prepared on polyethylene terephthalate (PET) substrate by electroless plating in combination with UV/ozonolysis irradiation under optimized cobalt sulfate heptahydrate concentration, pH value, plating temperature and time. The copper polyalloy/PET composite can be obtained in three steps, namely: (i) the generation of oxygen-containing functionalities (carboxylic groups) onto PET surface through UV irradiation combined with ozone, (ii) Cu seeding catalysts were obtained after being immersed into cupric citrate and NaBH{sub 4} solutions subsequently, and (iii) Cu-Co-P polyalloy metallization using electroless plating bath. Attenuated total reflection fourier transformation infrared spectrometer (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), water contact angle measurement and energy dispersive X-ray analysis (EDAX) were utilized to track the surface changes during the whole process. The electroless plating conditions were optimized by an orthogonal experiment (L{sub 9}(3){sup 4}) for Cu-Co-P coating as follows: CoSO{sub 4}·7H{sub 2}O addition of 0.08 M, pH value, plating temperature and time were set on 10.0, 35 °C and 25 min, respectively. Under the optimal conditions, copper

  10. Mutagenic and epigenetic influence of caffeine on the frequencies of UV-induced ouabain-resistant Chinese hamster cells

    International Nuclear Information System (INIS)

    Chang, Chia-Cheng; Philipps, C.; Trosko, J.E.; Hart, R.W.

    1977-01-01

    Caffeine, given as a post-treatment to UV-irradiated Chinese hamster cells in vitro, modified the frequency of induced mutations at the ouabain resistance locus. Mutation frequencies were increased when caffeine was added only for the DNA repair and mutation fixation period. When caffeine was added after the DNA repair and mutation fixation period, or immediately after DNA damage and for the entire repair and selection period, mutation frequencies were reduced. A hypothesis, given to explain both results, is that caffeine, by blocking a constitutive 'error-free' postreplication repair process, allows an 'error-prone' DNA repair process to produce many mutations. Moreover, caffeine, possibly by modifying C-AMP metabolism, causes a repression of induced mutations which, in effect, explains its anti-mutagenic and anti-carcinogenic properties

  11. Development of bushing material with higher corrosion and wear resistance; Taishoku taimamosei dogokin bush zairyo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kira, T; Yokota, H; Kamiya, S [Taiho Kogyo Co. Ltd., Osaka (Japan)

    1997-10-01

    Recent diesel engines require a higher performance and a longer life. Due to higher cylinder pressure, the operating load and temperature of piston pin bushings become higher. Therefore, higher load capacity, higher wear resistance and higher corrosion resistance are required for piston pin bushings. For this reason, we have studied the effect of components added to copper alloy upon the corrosion resistance and the effect of hard particles dispersed in copper matrix upon the wear resistance and the influence of hard particles on the machinablity of materials. Based on the experimental results, we have developed a new bushing material improving wear and corrosion resistance. 17 figs., 3 tabs.

  12. Combined advanced finishing and UV laser conditioning process for producing damage resistant optics

    Science.gov (United States)

    Menapace, Joseph A.; Peterson, John E.; Penetrante, Bernardino M.; Miller, Philip E.; Parham, Thomas G.; Nichols, Michael A.

    2005-07-26

    A method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects, and are better capable of resisting optical deterioration upon exposure to a high-power laser beam.

  13. Higher fetal insulin resistance in Chinese pregnant women with gestational diabetes mellitus and correlation with maternal insulin resistance.

    Science.gov (United States)

    Wang, Qiuwei; Huang, Ruiping; Yu, Bin; Cao, Fang; Wang, Huiyan; Zhang, Ming; Wang, Xinhong; Zhang, Bin; Zhou, Hong; Zhu, Ziqiang

    2013-01-01

    The aim of this study was to determine the effect of gestational diabetes mellitus (GDM) on fetal insulin resistance or β-cell function in Chinese pregnant women with GDM. Maternal fasting blood and venous cord blood samples (reflecting fetal condition) were collected in 65 well-controlled Chinese GDM mothers (only given dietary intervention) and 83 control subjects. The insulin, glucose and proinsulin concentrations of both maternal and cord blood samples were measured, and the homeostasis model assessment of insulin resistance (HOMA-IR) and the proinsulin-to-insulin ratios (an indicator of fetal β-cell function) were calculated in maternal and cord blood respectively. Both maternal and fetal levels of insulin, proinsulin and HOMA-IR but not proinsulin-to-insulin ratios were significantly higher in the GDM group than in the control group (maternal insulin, 24.8 vs. 15.4 µU/mL, P = 0.004, proinsulin, 23.3 vs. 16.2 pmol/L, P = 0.005, and HOMA-IR, 5.5 vs. 3.5, P = 0.041, respectively; fetal: insulin, 15.1 vs. 7.9 µU/mL, Pinsulin ratios was significantly correlated to maternal HOMA-IR (r = 0.307, P = 0.019), in the pregnant women with GDM. Fetal insulin resistance was higher in Chinese pregnant women with GDM than control subjects, and correlated with maternal insulin resistance.

  14. Study on the resistance of haloferax radiotolerans, an extreme Halophilic archaebacterium from Uromia lake against ultraviolet (UV) light and 60Co gamma-rays

    International Nuclear Information System (INIS)

    Asgarni, E.; Shirzad, M.; Soudi, M. R.; Shahmohammadi, H. R.; Falsafi, T.

    2006-01-01

    In this work, the capacity of an extreme halophilic archaebacterium, isolated from Uromia lake, Haloferax radiotolerans to withstand the lethal effects of ultraviolet light (UV),and 60 Co r-rays has been studied. The resistibility of this organism against the DNA-damaging agents was evaluated by calculating of the survival fractions at different dose rates of W and 60 Co r-rays radiations and compared with those of Escherichia coli B/r (a radioresistant strain of E. coli). D 37 values for Haloferax radiotolerans and E. coli B/r were 23 1, and 9 J/m 2 , respectively, by exposure to the UV light. They were 645, and 99 Gy, respectively, by exposure to 60 Co r-rays. Against these agents, Haloferax radiotolerans shows much more resistance compare to that of E. coli B/r. This is categorized as the first report of resistibility in the member of Archaea

  15. UV and γ-ray resistance of poly(N-methylmaleimide-alt-isobutene) and poly(diisopropyl fumarate) as transparent polymer films

    Science.gov (United States)

    Imaizumi, Ryota; Furuta, Masakazu; Okamura, Haruyuki; Matsumoto, Akikazu

    2017-09-01

    UV and γ-ray resistance of transparent polymers obtained by radical polymerization of maleic and fumaric acid derivatives, i.e., an alternating copolymer of N-methylmaleimide and isobutene (PMI) and poly(diisopropyl fumarate) (PDiPF), was investigated. Transmittance in UV and visible regions of these polymers were examined after UV irradiation and compared with the results for poly(methyl methacrylate) (PMMA) and polycarbonate (PC) as conventional transparent polymers. The order of stability toward UV irradiation was PMMA≈PDiPF>PMI>>PC, deduced from changes in the transmittance of 380 nm light. Tensile mechanical properties, such as elastic modulus, maximum strength, and elongation values of PMI, PDiPF, and PMMA were also investigated after UV and γ-radiation. UV irradiation induced the side chain scission of PMI and PDiPF via Norrish I type reaction as well as crosslinking by combination between formed polymer radicals, leading to deterioration in their optical and mechanical properties. γ-radiation induced significant changes in molecular weight and mechanical properties of the polymers. In conclusion, PMI exhibited unchanged mechanical properties and PDiPF maintained its high transparency under various irradiation conditions.

  16. Higher fetal insulin resistance in Chinese pregnant women with gestational diabetes mellitus and correlation with maternal insulin resistance.

    Directory of Open Access Journals (Sweden)

    Qiuwei Wang

    Full Text Available OBJECTIVE: The aim of this study was to determine the effect of gestational diabetes mellitus (GDM on fetal insulin resistance or β-cell function in Chinese pregnant women with GDM. MEASUREMENTS: Maternal fasting blood and venous cord blood samples (reflecting fetal condition were collected in 65 well-controlled Chinese GDM mothers (only given dietary intervention and 83 control subjects. The insulin, glucose and proinsulin concentrations of both maternal and cord blood samples were measured, and the homeostasis model assessment of insulin resistance (HOMA-IR and the proinsulin-to-insulin ratios (an indicator of fetal β-cell function were calculated in maternal and cord blood respectively. RESULTS: Both maternal and fetal levels of insulin, proinsulin and HOMA-IR but not proinsulin-to-insulin ratios were significantly higher in the GDM group than in the control group (maternal insulin, 24.8 vs. 15.4 µU/mL, P = 0.004, proinsulin, 23.3 vs. 16.2 pmol/L, P = 0.005, and HOMA-IR, 5.5 vs. 3.5, P = 0.041, respectively; fetal: insulin, 15.1 vs. 7.9 µU/mL, P<0.001, proinsulin, 25.8 vs. 15.1 pmol/L, P = 0.015, and HOMA-IR, 2.8 vs. 1.4, P = 0.017, respectively. Fetal HOMA-IR but not proinsulin-to-insulin ratios was significantly correlated to maternal HOMA-IR (r = 0.307, P = 0.019, in the pregnant women with GDM. CONCLUSIONS: Fetal insulin resistance was higher in Chinese pregnant women with GDM than control subjects, and correlated with maternal insulin resistance.

  17. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

    There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

  18. Slower phloem transport in gymnosperm trees can be attributed to higher sieve element resistance.

    Science.gov (United States)

    Liesche, Johannes; Windt, Carel; Bohr, Tomas; Schulz, Alexander; Jensen, Kaare H

    2015-04-01

    In trees, carbohydrates produced in photosynthesizing leaves are transported to roots and other sink organs over distances of up to 100 m inside a specialized transport tissue, the phloem. Angiosperm and gymnosperm trees have a fundamentally different phloem anatomy with respect to cell size, shape and connectivity. Whether these differences have an effect on the physiology of carbohydrate transport, however, is not clear. A meta-analysis of the experimental data on phloem transport speed in trees yielded average speeds of 56 cm h(-1) for angiosperm trees and 22 cm h(-1) for gymnosperm trees. Similar values resulted from theoretical modeling using a simple transport resistance model. Analysis of the model parameters clearly identified sieve element (SE) anatomy as the main factor for the significantly slower carbohydrate transport speed inside the phloem in gymnosperm compared with angiosperm trees. In order to investigate the influence of SE anatomy on the hydraulic resistance, anatomical data on SEs and sieve pores were collected by transmission electron microscopy analysis and from the literature for 18 tree species. Calculations showed that the hydraulic resistance is significantly higher in the gymnosperm than in angiosperm trees. The higher resistance is only partially offset by the considerably longer SEs of gymnosperms. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Different small, acid-soluble proteins of the alpha/beta type have interchangeable roles in the heat and UV radiation resistance of Bacillus subtilis spores

    International Nuclear Information System (INIS)

    Mason, J.M.; Setlow, P.

    1987-01-01

    Spores of Bacillus subtilis strains which carry deletion mutations in one gene (sspA) or two genes (sspA and sspB) which code for major alpha/beta-type small, acid-soluble spore proteins (SASP) are known to be much more sensitive to heat and UV radiation than wild-type spores. This heat- and UV-sensitive phenotype was cured completely or in part by introduction into these mutant strains of one or more copies of the sspA or sspB genes themselves; multiple copies of the B. subtilis sspD gene, which codes for a minor alpha/beta-type SASP; or multiple copies of the SASP-C gene, which codes for a major alpha/beta-type SASP of Bacillus megaterium. These findings suggest that alpha/beta-type SASP play interchangeable roles in the heat and UV radiation resistance of bacterial spores

  20. Fabrication of modified hydrogenated castor oil/GPTMS-ZnO composites and effect on UV resistance of leather.

    Science.gov (United States)

    Ma, Jianzhong; Duan, Limin; Lu, Juan; Lyu, Bin; Gao, Dangge; Wu, Xionghu

    2017-06-16

    Leather products are made from the natural skin collagen fibers. It is vulnerable to the environmental factor such as solar ultraviolet irradiation in the using process. Therefore anti-UV performance is a very important quality, particularly for chrome-free leather. ZnO is a well-known UV absorber commonly used in the cosmetic industry. We have investigated its potential to increase the anti-UV performance of chrome-free leather. Modified hydrogenated castor oil/GPTMS-ZnO (MHCO/ GPTMS-ZnO) composites were prepared using spherical ZnO nanoparticles, hydrogenated castor oil, maleic anhydride and sodium bisulfite. MHCO/GPTMS-ZnO composites have better anti-UV ability and stability. MHCO/GPTMS-ZnO composites were applied to the leather processing. The treated samples were exposed to artificial sunlight. Anti-yellowing tests showed that MHCO/GPTMS-ZnO composites significantly improved anti-UV performance of leather.

  1. Childhood craniopharyngioma: greater hypothalamic involvement before surgery is associated with higher homeostasis model insulin resistance index

    Science.gov (United States)

    Trivin, Christine; Busiah, Kanetee; Mahlaoui, Nizar; Recasens, Christophe; Souberbielle, Jean-Claude; Zerah, Michel; Sainte-Rose, Christian; Brauner, Raja

    2009-01-01

    Background Obesity seems to be linked to the hypothalamic involvement in craniopharyngioma. We evaluated the pre-surgery relationship between the degree of this involvement on magnetic resonance imaging and insulin resistance, as evaluated by the homeostasis model insulin resistance index (HOMA). As insulin-like growth factor 1, leptin, soluble leptin receptor (sOB-R) and ghrelin may also be involved, we compared their plasma concentrations and their link to weight change. Methods 27 children with craniopharyngioma were classified as either grade 0 (n = 7, no hypothalamic involvement), grade 1 (n = 8, compression without involvement), or grade 2 (n = 12, severe involvement). Results Despite having similar body mass indexes (BMI), the grade 2 patients had higher glucose, insulin and HOMA before surgery than the grade 0 (P = 0.02, craniopharyngioma before surgery seems to determine the degree of insulin resistance, regardless of the BMI. The pre-surgery HOMA values were correlated with the post-surgery weight gain. This suggests that obesity should be prevented by reducing inn secretion in those cases with hypothalamic involvement. PMID:19341477

  2. Childhood craniopharyngioma: greater hypothalamic involvement before surgery is associated with higher homeostasis model insulin resistance index

    Directory of Open Access Journals (Sweden)

    Sainte-Rose Christian

    2009-04-01

    Full Text Available Abstract Background Obesity seems to be linked to the hypothalamic involvement in craniopharyngioma. We evaluated the pre-surgery relationship between the degree of this involvement on magnetic resonance imaging and insulin resistance, as evaluated by the homeostasis model insulin resistance index (HOMA. As insulin-like growth factor 1, leptin, soluble leptin receptor (sOB-R and ghrelin may also be involved, we compared their plasma concentrations and their link to weight change. Methods 27 children with craniopharyngioma were classified as either grade 0 (n = 7, no hypothalamic involvement, grade 1 (n = 8, compression without involvement, or grade 2 (n = 12, severe involvement. Results Despite having similar body mass indexes (BMI, the grade 2 patients had higher glucose, insulin and HOMA before surgery than the grade 0 (P = 0.02, The data for the whole population before and 6–18 months after surgery showed increases in BMI (P Conclusion The hypothalamic involvement by the craniopharyngioma before surgery seems to determine the degree of insulin resistance, regardless of the BMI. The pre-surgery HOMA values were correlated with the post-surgery weight gain. This suggests that obesity should be prevented by reducing inn secretion in those cases with hypothalamic involvement.

  3. The genetic characterization of lexB32, lexB33 and lexB35 mutations of Escherichia coli: location and complementation pattern for UV resistance

    International Nuclear Information System (INIS)

    Glickman, B.W.; Guijt, N.; Morand, P.; Centre National de la Recherche Scientifique, 91 - Gif-sur-Yvette

    1977-01-01

    Mutants of LexB have been isolated by their resistance to lysogenic induction by thymine starvation, their resistance to thymine starvation and on the basis of their UV sensitivity. Here, three mutations identified originally in strains lacking mutagenic response to UV-irradiation, unmB (Kato and Shinoura, 1977), have been further characterized, mapped by P1-mediated transduction with srl into the recA-tif-zab-lexB cluster at the lexB position and analysed for complementation with various lexB and recA mutations. From the results it was concluded that unmB mutations are identical to lexB mutations; consequently these mutations have been termed lexB32, lexB33 and lexB35. The mutations lexB33 and lexB35 do not complement any of the other lexB mutations and define therefore a new complementation type. The lexB32 mutation, which like the lexB34 mutation, results in moderate UV sensitivity has a complementation pattern similar to that of lexB34. However, unlike lexB34 the lexB32 behaves like a leaky mutation. The results are discussed in relation to the recA gene product and its control. (orig.) [de

  4. Resistance of 3T3 mouse cells to UV light in relation to excision and transfer of dimers to daughter strands

    Energy Technology Data Exchange (ETDEWEB)

    Menck, C F.M.; Meneghini, R [Sao Paulo Univ. (Brazil). Inst. de Quimica

    1982-04-01

    Mouse cells (3T3 line) and human fibroblasts are equally sensitive to UV light. At fluences of 2.0-2.5 J/m/sup 2/ mouse cells excise only 20% of the pyrimidine dimers as compared to 80% excised by human fibroblasts. This fluence allows 37% survival in both cases. Hence, mouse cells are more resistant to the same burden of unexcised dimers. The reason for this increased tolerance to dimers does not seem to be due to a recombinational mechanism, as judged by the fact that only ca. 5% of the dimers are transferred from parental to daughter strands. The transfer of dimers was measured by the Micrococcus luteus UV endonuclease assay, irradiating cells at G/sub 1/ to avoid artifacts arising from introduction of dimers in nascent strands. The possibility of other mechanisms being involved in the process of tolerance to DNA lesions is discussed.

  5. In situ deposition of graphene nanosheets on wood surface by one-pot hydrothermal method for enhanced UV-resistant ability

    International Nuclear Information System (INIS)

    Wan, Caichao; Jiao, Yue; Li, Jian

    2015-01-01

    Graphical abstract: - Highlights: • The graphene/wood nanocomposites were fabricated via a mild fast one-pot hydrothermal method. • Graphene nanosheets were in situ deposited on the surface of the wood matrix. • The incorporation of graphene nanosheets results in the improvement in the thermal stability of the graphene/wood. • The graphene/wood exhibits superior UV resistance performance. - Abstract: Graphene nanosheets were successfully in situ deposited on the surface of the wood matrix via a mild fast one-pot hydrothermal method, and the resulting hybrid graphene/wood (GW) were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA). According to the results, the wood matrix was evenly coated by dense uninterrupted multilayer graphene membrane structure, which was formed by layer-by-layer self-assembly of graphene nanosheets. Meanwhile, the graphene coating also induced significant improvement in the thermal stability of GW in comparison with that of the original wood (OW). Accelerated weathering tests were employed to measure and determine the UV-resistant ability of OW and GW. After about six hundred hours of experiments, the surface color change of GW was much less than that of OW; besides, the Fourier transform infrared spectroscopy (FTIR) analysis also proved the less significant changes in surface chemical compositions of GW. The results both indicated that the graphene coating effectively protected wood surface from UV damage. Therefore, this class of GW composite might be expected to be served as high-performance wooden building material for outdoor or some particular harsh environments like strong UV radiation regions use

  6. UV-LED Curing Efficiency of Wood Coatings

    Directory of Open Access Journals (Sweden)

    Véronic Landry

    2015-12-01

    Full Text Available Ultraviolet light emitting diodes (UV-LEDs have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerful enough to cure UV high solids acrylate coatings while satisfactory results can be obtained for UV water-based formulations. In fact, conversion percentages were found to be low for the high solids coatings, leaving the coatings tacky. Higher conversion percentages were obtained for the UV water-based formulations. As a result, mass loss, hardness, and scratch resistance found for the samples cured by UV-LED were closed to the ones found for the samples cured using the UV microwave lamp.

  7. Antimicrobial Resistance Percentages of Salmonella and Shigella in Seafood Imported to Jordan: Higher Percentages and More Diverse Profiles in Shigella.

    Science.gov (United States)

    Obaidat, Mohammad M; Bani Salman, Alaa E

    2017-03-01

    This study determined the prevalence and antimicrobial resistance of human-specific ( Shigella spp.) and zoonotic ( Salmonella enterica ) foodborne pathogens in internationally traded seafood. Sixty-four Salmonella and 61 Shigella isolates were obtained from 330 imported fresh fish samples from Egypt, Yemen, and India. The pathogens were isolated on selective media, confirmed by PCR, and tested for antimicrobial resistance. Approximately 79 and 98% of the Salmonella and Shigella isolates, respectively, exhibited resistance to at least one antimicrobial, and 8 and 49% exhibited multidrug resistance (resistance to three or more antimicrobial classes). Generally, Salmonella exhibited high resistance to amoxicillin-clavulanic acid, cephalothin, streptomycin, and ampicillin; very low resistance to kanamycin, tetracycline, gentamicin, chloramphenicol, nalidixic acid, sulfamethoxazole-trimethoprim, and ciprofloxacin; and no resistance to ceftriaxone. Meanwhile, Shigella spp. exhibited high resistance to tetracycline, amoxicillin-clavulanic acid, cephalothin, streptomycin, and ampicillin; low resistance to kanamycin, nalidixic acid, sulfamethoxazole-trimethoprim, and ceftriaxone; and very low resistance to gentamicin and ciprofloxacin. Salmonella isolates exhibited 14 resistance profiles, Shigella isolates 42. This study is novel in showing that a human-specific pathogen has higher antimicrobial resistance percentages and more diverse profiles than a zoonotic pathogen. Thus, the impact of antimicrobial use in humans is as significant as, if not more significant than, it is in animals in spreading antibiotic resistance through food. This study also demonstrates that locally derived antimicrobial resistance can spread and pose a public health risk worldwide through seafood trade and that high resistance would make a possible outbreak difficult to control. So, capacity building and monitoring harvest water areas are encouraged in fish producing countries.

  8. A distinct boundary between the higher brain's susceptibility to ischemia and the lower brain's resistance.

    Directory of Open Access Journals (Sweden)

    C Devin Brisson

    Full Text Available Higher brain regions are more susceptible to global ischemia than the brainstem, but is there a gradual increase in vulnerability in the caudal-rostral direction or is there a discrete boundary? We examined the interface between `higher` thalamus and the hypothalamus the using live brain slices where variation in blood flow is not a factor. Whole-cell current clamp recording of 18 thalamic neurons in response to 10 min O2/glucose deprivation (OGD revealed a rapid anoxic depolarization (AD from which thalamic neurons do not recover. Newly acquired neurons could not be patched following AD, confirming significant regional thalamic injury. Coinciding with AD, light transmittance (LT imaging during whole-cell recording showed an elevated LT front that initiated in midline thalamus and that propagated into adjacent hypothalamus. However, hypothalamic neurons patched in paraventricular nucleus (PVN, n= 8 magnocellular and 12 parvocellular neurons and suprachiasmatic nucleus (SCN, n= 18 only slowly depolarized as AD passed through these regions. And with return to control aCSF, hypothalamic neurons repolarized and recovered their input resistance and action potential amplitude. Moreover, newly acquired hypothalamic neurons could be readily patched following exposure to OGD, with resting parameters similar to neurons not previously exposed to OGD. Thalamic susceptibility and hypothalamic resilience were also observed following ouabain exposure which blocks the Na(+/K(+ pump, evoking depolarization similar to OGD in all neuronal types tested. Finally, brief exposure to elevated [K(+]o caused spreading depression (SD, a milder, AD-like event only in thalamic neurons so SD generation is regionally correlated with strong AD. Therefore the thalamus-hypothalamus interface represents a discrete boundary where neuronal vulnerability to ischemia is high in thalamus (like more rostral neocortex, striatum, hippocampus. In contrast hypothalamic neurons are

  9. DNA replication in necessary for fixing induced mutations to streptomycin-resistance in UV-irradiated Escherichia coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Dubinin, N P; Filippov, V D

    1986-01-01

    A suspension of E.coli cells has been subjected to UV radiation, then it has been incubated in the growth medium for 15 min. After that one of the portions was incubated with nalidixic acid (NA), and the other one without it in the presence of an antibiotic. Frequency of mutations depending on or irrespective of photoactivation, has been determined. Dependence of Str mutation fixing, induced by low UV radiation doses, on DNA synthesis is determined. Results indicate that both photoreactivation of mutations and its senstivity to mfd system are simultaneously lost.

  10. Human isolates of Salmonella enterica serovar Typhimurium from Taiwan displayed significantly higher levels of antimicrobial resistance than those from Denmark.

    Science.gov (United States)

    Torpdahl, Mia; Lauderdale, Tsai-Ling; Liang, Shiu-Yun; Li, Ishien; Wei, Sung-Hsi; Chiou, Chien-Shun

    2013-02-01

    Salmonella enterica serovar Typhimurium is a major zoonotic pathogen with a high prevalence of antimicrobial resistance. This pathogen can disseminate across borders and spread far distances via the food trade and international travel. In this study, we compared the genotypes and antimicrobial resistance of 378 S. Typhimurium isolates collected in Taiwan and Denmark between 2009 and 2010. Genotyping revealed that many S. Typhimurium strains were concurrently circulating in Taiwan, Denmark and other countries in 2009 and 2010. When compared to the isolates collected from Denmark, the isolates from Taiwan displayed a significantly higher level of resistance to 11 of the 12 tested antimicrobials. Seven genetic clusters (A-G) were designated for the isolates. A high percentage of the isolates in genetic clusters C, F and G were multidrug-resistant. Of the isolates in cluster C, 79.2% were ASSuT-resistant, characterized by resistance to ampicillin, streptomycin, sulfamethoxazole, and tetracycline. In cluster F, 84.1% of the isolates were ACSSuT-resistant (resistant to ASSuT and chloramphenicol). Cluster G was unique to Taiwan and characterized in most isolates by the absence of three VNTRs (ST20, ST30 and STTR6) as well as a variety of multidrug resistance profiles. This cluster exhibited very high to extremely high levels of resistance to several first-line drugs, and among the seven clusters, it displayed the highest levels of resistance to cefotaxime and ceftazidime, ciprofloxacin and gentamicin. The high prevalence of antimicrobial resistance in S. Typhimurium from Taiwan highlights the necessity to strictly regulate the use of antimicrobials in the agriculture and human health care sectors. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Effects of soybean resistance on variability in life history traits of the higher trophic level parasitoid Meteorus pulchricornis (Hymenoptera: Braconidae).

    Science.gov (United States)

    Li, X; Li, B; Xing, G; Meng, L

    2017-02-01

    To extrapolate the influence of plant cultivars varying in resistance levels to hosts on parasitoid life history traits, we estimated variation in parasitoid developmental and reproductive performances as a function of resistance in soybean cultivars, which were randomly chosen from a line of resistant genotypes. Our study showed that the parasitoid Meteorus pulchricornis varied widely in offspring survival and lifetime fecundity, but varied slightly in development time and adult body size, in response to the soybean cultivars that varied in resistance to the host Spodoptera litura. Furthermore, the variability in survival and lifetime fecundity was different between attacking the 2nd and the 4th instar host larvae, varying more in survival but less in lifetime fecundity when attacking the 4th than 2nd instar larvae. Our study provides further evidence supporting that plant resistance to herbivorous hosts have variable effects on different life history traits of higher trophic level parasitoids.

  12. Higher Fetal Insulin Resistance in Chinese Pregnant Women with Gestational Diabetes Mellitus and Correlation with Maternal Insulin Resistance

    OpenAIRE

    Wang, Qiuwei; Huang, Ruiping; Yu, Bin; Cao, Fang; Wang, Huiyan; Zhang, Ming; Wang, Xinhong; Zhang, Bin; Zhou, Hong; Zhu, Ziqiang

    2013-01-01

    OBJECTIVE: The aim of this study was to determine the effect of gestational diabetes mellitus (GDM) on fetal insulin resistance or β-cell function in Chinese pregnant women with GDM. MEASUREMENTS: Maternal fasting blood and venous cord blood samples (reflecting fetal condition) were collected in 65 well-controlled Chinese GDM mothers (only given dietary intervention) and 83 control subjects. The insulin, glucose and proinsulin concentrations of both maternal and cord blood samples were measur...

  13. Resistance of the genome of Escherichia coli and Listeria monocytogenes to irradiation evaluated by the induction of cyclobutane pyrimidine dimers and 6-4 photoproducts using gamma and UV-C radiations

    Science.gov (United States)

    Beauchamp, S.; Lacroix, M.

    2012-08-01

    The effect of gamma and UV-C irradiation on the production of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4 PPs) in DNA was investigated to compare the natural resistance of the genome of a Gram-positive bacterium and a Gram-negative bacterium against irradiation. Solution of pure DNA and bacterial strains Listeria monocytogenes and Escherichia coli were irradiated using gamma and UV-C rays. Extracted DNA from bacteria and pure DNA samples were then analysed by ELISA using anti-CPDs and anti-6-4 PPs monoclonal antibodies. The results show that gamma rays, as well as UV-C rays, induce the formation of CPDs and 6-4 PPs in DNA. During UV-C irradiation, the three samples showed a difference in their sensitivity against formation of CPDs (P≤0.05). Pure DNA was the most sensitive while the genome of L. monocytogenes was the most resistant. Also during UV-C irradiation, the genome of L. monocytogenes was the only one to show a significant resistance against formation of 6-4 PPs (P≤0.05). During gamma irradiation, for both types of lesion, pure DNA and the genome of E. coli did not show significant difference in their sensitivity (P>0.05) while the genome of L. monocytogenes showed a resistance against formation of CPDs and 6-4 PPs.

  14. Does trans-lesion synthesis explain the UV-radiation resistance of DNA synthesis in C.elegans embryos?

    International Nuclear Information System (INIS)

    Hartman, Phil; Reddy, Jennifer; Svendsen, Betty-Ann

    1991-01-01

    Over 10-fold larger fluences were required to inhibit both DNA synthesis and cell division in wild-type C.elegans embryos as compared with other model systems or C.elegans rad mutants. In addition, unlike in other organisms, the molecular weight of daughter DNA strands was reduced only after large, superlethal fluences. The molecular weight of nascent DNA fragments exceeded the interdimer distance by up to 19-fold, indicating that C.elegans embryos can replicate through non-instructional lesions. This putative trans-lesion synthetic capability may explain the refractory nature of UV-radiation on embryonic DNA synthesis and nuclear division in C.elegans. (author). 42 refs.; 7 figs

  15. Does trans-lesion synthesis explain the UV-radiation resistance of DNA synthesis in C. elegans embryos

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Phil; Reddy, Jennifer; Svendsen, Betty-Ann [Texas Christian Univ., Fort Worth, TX (United States). Dept. of Biology

    1991-09-01

    Over 10-fold larger fluences were required to inhibit both DNA synthesis and cell division in wild-type C.elegans embryos as compared with other model systems or C.elegans rad mutants. In addition, unlike in other organisms, the molecular weight of daughter DNA strands was reduced only after large, superlethal fluences. The molecular weight of nascent DNA fragments exceeded the interdimer distance by up to 19-fold, indicating that C.elegans embryos can replicate through non-instructional lesions. This putative trans-lesion synthetic capability may explain the refractory nature of UV-radiation on embryonic DNA synthesis and nuclear division in C.elegans. (author). 42 refs.; 7 figs.

  16. H{sub 2}O{sub 2} and/or TiO{sub 2} photocatalysis under UV irradiation for the removal of antibiotic resistant bacteria and their antibiotic resistance genes

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Changsheng [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Kai [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wuxi SensingNet Industrialization Research Institute, Wuxi 214000 (China); Hou, Song; Wan, Li; Lv, Jiapei; Zhang, Yuan [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Qu, Xiaodong [State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, and Department of Water Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038 (China); Chen, Shuyi [Wuxi SensingNet Industrialization Research Institute, Wuxi 214000 (China); Xu, Jian, E-mail: xujian@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2017-02-05

    Highlights: • TiO{sub 2} thin film was successfully synthesized for treating ARB and ARGs from water. • More than 5.5 log units of ARB reduction was achieved by TiO{sub 2} under UV irradiation. • With TiO{sub 2}, ARGs were reduced by more than 5 log units under UV irradiation. • TiO{sub 2} could remove both intracellular and extracellular forms of ARGs. - Abstract: Inactivating antibiotic resistant bacteria (ARB) and removing antibiotic resistance genes (ARGs) are very important to prevent their spread into the environment. Previous efforts have been taken to eliminate ARB and ARGs from aqueous solution and sludges, however, few satisfying results have been obtained. This study investigated whether photocatalysis by TiO{sub 2} was able to reduce the two ARGs, mecA and ampC, within the host ARB, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. The addition of H{sub 2}O{sub 2} and matrix effect on the removal of ARB and ARGs were also studied. TiO{sub 2} thin films showed great effect on both ARB inactivation and ARGs removal. Approximately 4.5-5.0 and 5.5–5.8 log ARB reductions were achieved by TiO{sub 2} under 6 and 12 mJ/cm{sup 2} UV{sub 254} fluence dose, respectively. For ARGs, 5.8 log mecA reduction and 4.7 log ampC reduction were achieved under 120 mJ/cm{sup 2} UV{sub 254} fluence dose in the presence of TiO{sub 2}. Increasing dosage of H{sub 2}O{sub 2} enhanced the removal efficiencies of ARB and ARGs. The results also demonstrated that photocatalysis by TiO{sub 2} was capable of removing both intracellular and extracellular forms of ARGs. This study provided a potential alternative method for the removal of ARB and ARGs from aqueous solution.

  17. Toward a Theoretical Model of Decision-Making and Resistance to Change among Higher Education Online Course Designers

    Science.gov (United States)

    Dodd, Bucky J.

    2013-01-01

    Online course design is an emerging practice in higher education, yet few theoretical models currently exist to explain or predict how the diffusion of innovations occurs in this space. This study used a descriptive, quantitative survey research design to examine theoretical relationships between decision-making style and resistance to change…

  18. New Higher Education President Integration: Change and Resistance Viewed through Social Power Bases and a Change Model Lens

    Science.gov (United States)

    Gearin, Christopher A.

    2017-01-01

    This study investigates how new presidents of higher education institutions struggle to understand their organisations, paying special attention to campus resistance, and how new presidents manage institutional dynamics and expectations. A qualitative study using a phenomenological approach is conducted with 11 single-campus presidents of…

  19. Survival of spores of the UV-resistant Bacillus subtilis strain MW01 after exposure to low-earth orbit and simulated martian conditions: data from the space experiment ADAPT on EXPOSE-E.

    Science.gov (United States)

    Wassmann, Marko; Moeller, Ralf; Rabbow, Elke; Panitz, Corinna; Horneck, Gerda; Reitz, Günther; Douki, Thierry; Cadet, Jean; Stan-Lotter, Helga; Cockell, Charles S; Rettberg, Petra

    2012-05-01

    In the space experiment "Molecular adaptation strategies of microorganisms to different space and planetary UV climate conditions" (ADAPT), bacterial endospores of the highly UV-resistant Bacillus subtilis strain MW01 were exposed to low-Earth orbit (LEO) and simulated martian surface conditions for 559 days on board the European Space Agency's exposure facility EXPOSE-E, mounted outside the International Space Station. The survival of B. subtilis MW01 spores from both assays (LEO and simulated martian conditions) was determined by a colony-formation assay after retrieval. It was clearly shown that solar extraterrestrial UV radiation (λ≥110 nm) as well as the martian UV spectrum (λ≥200 nm) was the most deleterious factor applied; in some samples only a few spore survivors were recovered from B. subtilis MW01 spores exposed in monolayers. However, if shielded from solar irradiation, about 8% of MW01 spores survived in LEO conditions, and 100% survived in simulated martian conditions, compared to the laboratory controls. The results demonstrate the effect of shielding against the high inactivation potential of extraterrestrial solar UV radiation, which limits the chances of survival of even the highly UV-resistant strain of B. subtilis MW01 in the harsh environments of outer space and the martian surface.

  20. Resistance to nitrofurantoin and UV-irradiation in recA; uvrA; and uvrA, lexA, Escherichia coli mutants conferred by an R-plasmid from an Escherichia coli clinical isolate

    Energy Technology Data Exchange (ETDEWEB)

    Obaseiki-Ebor, E.E. (Univ. of Benin, Benin City (Nigeria). Faculty of Pharmacy, Dept. of Pharmaceutical Microbiology)

    1984-01-01

    There have been some reports of R-plasmids conferring nitrofuran resistance by decreasing the reduction of nitrofurantoin. The mechanism by which these R-plasmids mediate nitrofurantoin resistance is still not properly understood. Since DNA repair mutants are very sensitive to nitrofurantoin, it was therefore of interest to see whether R-plasmids conferring nitrofurantoin resistance affected the nitrofurantoin sensitivity of recA; uvrA and uvrA, lexA strains of E. coli K-12. Protection against UV-irradiation was also estimated. The experiments showed that the nitrofurantoin resistance conferred by R-plasmid pBN105 was not due to defective nitrofurantoin reduction or altered permeability of the cell. Because it is known that repair-deficient bacteria have increased susceptibility to nitrofurantoin, it may be suggested that the mechanisms of UV and nitrofurantoin protection conferred by pBN105 to the DNA repair mutant strains are related.

  1. Resistance to nitrofurantoin and UV-irradiation in recA; uvrA; and uvrA, lexA, Escherichia coli mutants conferred by an R-plasmid from an Escherichia coli clinical isolate

    International Nuclear Information System (INIS)

    Obaseiki-Ebor, E.E.

    1984-01-01

    There have been some reports of R-plasmids conferring nitrofuran resistance by decreasing the reduction of nitrofurantoin. The mechanism by which these R-plasmids mediate nitrofurantoin resistance is still not properly understood. Since DNA repair mutants are very sensitive to nitrofurantoin, it was therefore of interest to see whether R-plasmids conferring nitrofurantoin resistance affected the nitrofurantoin sensitivity of recA; uvrA and uvrA, lexA strains of E. coli K-12. Protection against UV-irradiation was also estimated. The experiments showed that the nitrofurantoin resistance conferred by R-plasmid pBN105 was not due to defective nitrofurantoin reduction or altered permeability of the cell. Because it is known that repair-deficient bacteria have increased susceptibility to nitrofurantoin, it may be suggested that the mechanisms of UV and nitrofurantoin protection conferred by pBN105 to the DNA repair mutant strains are related. (Auth.)

  2. Waterborne UV coating for industrial applications

    International Nuclear Information System (INIS)

    Bhattacharya, I.N.

    2007-01-01

    (Full Text): Solvent borne industrial coatings are being replaced by environment friendly coatings like Ultra Violet (UV) or Electron Beam (Eb) cured coatings, Powder coatings and Waterborne coatings. Waterborne systems enjoy the biggest share from this shift. UV and EB coatings provide the advantages of instant cure at room temperature, high scratch and abrasion resistance combined with excellent chemical resistance. Polyurethane (PU) chemistry is the dominant chemistry in Industrial coatings as they provide a very high level of performance. Most PU coatings are solvent based 2-component systems comprising of a resin and a cross linker. Polyurethane dispersions (PUD) in water in single pack are available but mainly addresses the Do It Yourself (DIY) market because of their slow drying speeds. Performance of PUD in most cases is inferior to solvent borne 2-component PU systems.Therefore the combination of PU dispersion and UV/EB curable technology has led to new innovative waterborne polymers called UV curable polyurethane dispersions (UVPUD). UVPUD are zero VOC systems as they are coalescent free. They are higher in molecular weight than standard UV curable products resulting in lower shrinkage coatings and provide good adhesion to substrates. Their low-viscosity makes them suitable for application by spray, curtain coater and even roller coater, without having to use monomers. UVPUD display superior chemical and mechanical properties necessary to protect high quality surface from the challenging usage conditions. UVPUD resins are therefore tailor-made to address performance needs like excellence in outdoor durability, scratch resistance, stain resistance, adhesion etc. UVPUD technology is now growing rapidly in industrial coatings for applications such as resilient flooring, wooden parquet flooring, automotive interior plastics, mobile phones etc. (Author)

  3. Post-processing of fused silica and its effects on damage resistance to nanosecond pulsed UV lasers.

    Science.gov (United States)

    Ye, Hui; Li, Yaguo; Zhang, Qinghua; Wang, Wei; Yuan, Zhigang; Wang, Jian; Xu, Qiao

    2016-04-10

    HF-based (hydrofluoric acid) chemical etching has been a widely accepted technique to improve the laser damage performance of fused silica optics and ensure high-power UV laser systems at designed fluence. Etching processes such as acid concentration, composition, material removal amount, and etching state (etching with additional acoustic power or not) may have a great impact on the laser-induced damage threshold (LIDT) of treated sample surfaces. In order to find out the effects of these factors, we utilized the Taguchi method to determine the etching conditions that are helpful in raising the LIDT. Our results show that the most influential factors are concentration of etchants and the material etched away from the viewpoint of damage performance of fused silica optics. In addition, the additional acoustic power (∼0.6  W·cm-2) may not benefit the etching rate and damage performance of fused silica. Moreover, the post-cleaning procedure of etched samples is also important in damage performances of fused silica optics. Different post-cleaning procedures were, thus, experiments on samples treated under the same etching conditions. It is found that the "spraying + rinsing + spraying" cleaning process is favorable to the removal of etching-induced deposits. Residuals on the etched surface are harmful to surface roughness and optical transmission as well as laser damage performance.

  4. Removal of Organic Dyes from Industrial Wastewaters Using UV/H2O2, UV/H2O2/Fe (II, UV/H2O2/Fe (III Processes

    Directory of Open Access Journals (Sweden)

    Nezamaddin Daneshvar

    2007-03-01

    Full Text Available UV/H2O2, UV/H2O2/Fe (II and UV/H2O2/Fe (III processes are very effective in removing pollutants from wastewater and can be used for treatment of dyestuff units wastewaters. In this study, Rhodamine B was used as a typical organic dye. Rhodamine B has found wide applications in wax, leather, and paper industries. The results from this study showed that this dye was degradable in the presence of hydrogen peroxide under UV-C irradiation (30W mercury light and Photo-Fenton process. The dye was resistant to UV irradiation. In the absence of UV irradiation, the decolorization efficiency was very negligible in the presence of hydrogen. The effects of different system variables such as initial dye concentration, duration of UV irradiation, and initial hydrogen peroxide concentration were investigated in the UV/H2O2 process. Investigation of the kinetics of the UV/H2O2 process showed that the semi-log plot of the dye concentration versus time was linear, suggesting a first order reaction. It was found that Rhodamine B decolorization efficiencies in the UV/H2O2/Fe (II and UV/H2O2/Fe (III processes were higher than that in the UV/H2O2 process. Furthermore, a solution containing 20 ppm of Rhodamine B was decolorized in the presence 18 mM of H2O2 under UV irradiation for 15 minutes. It was also found that addition of 0.1 mM Fe(II or Fe(III to the solution containing  20  ppm of the dye and 5 mM H2O2 under UV light  illumination decreased removal time to 10 min.

  5. Slower phloem transport in gymnosperm trees can be attributed to higher sieve element resistance

    DEFF Research Database (Denmark)

    Liesche, Johannes; Windt, Carel; Bohr, Tomas

    2015-01-01

    resulted from theoretical modeling using a simple transport resistance model. Analysis of the model parameters clearly identified sieve element (SE) anatomy as the main factor for the significantly slower carbohydrate transport speed inside the phloem in gymnosperm compared with angiosperm trees. In order......In trees, carbohydrates produced in photosynthesizing leaves are transported to roots and other sink organs over distances of up to 100 m inside a specialized transport tissue, the phloem. Angiosperm and gymnosperm trees have a fundamentally different phloem anatomy with respect to cell size, shape...... and connectivity. Whether these differences have an effect on the physiology of carbohydrate transport, however, is not clear. A meta-analysis of the experimental data on phloem transport speed in trees yielded average speeds of 56 cm h−1 for angiosperm trees and 22 cm h−1 for gymnosperm trees. Similar values...

  6. High aspect ratio silver grid transparent electrodes using UV embossing process

    Directory of Open Access Journals (Sweden)

    Dong Jin Kim

    2017-10-01

    Full Text Available This study presents a UV embossing process to fabricate high aspect ratio silver grid transparent electrodes on a polymer film. Transparent electrodes with a high optical transmittance (93 % and low sheet resistance (4.6 Ω/sq were fabricated without any high temperature or vacuum processes. The strong adhesion force between the UV resin and the silver ink enables the fabrication of silver microstructures with an aspect ratio higher than 3. The high aspect ratio results in a low sheet resistance while maintaining a high optical transmittance. Multi-layer transparent electrodes were fabricated by repeating the proposed UV process. Additionally, a large-area of 8-inch touch panel was fabricated with the proposed UV process. The proposed UV process is a relatively simple and low cost process making it suitable for large-area production as well as mass production.

  7. Globalization/s: Reproduction and Resistance in the Internationalization of Higher Education

    Science.gov (United States)

    Beck, Kumari

    2012-01-01

    Internationalization of higher education has become a significant feature of the Canadian educational landscape. Considered to be a product of and response to globalization, internationalization is being critiqued for having an economic orientation. This paper will begin with a brief overview of internationalization research in Canada, and the…

  8. Resistances to Scientific Knowledge Production of Comparative Measurements of Dropout and Completion in European Higher Education

    Science.gov (United States)

    Carlhed, Carina

    2017-01-01

    The article is a critical sociological analysis of current transnational practices on creating comparable measurements of dropout and completion in higher education and the consequences for the conditions of scientific knowledge production on the topic. The analysis revolves around questions of epistemological, methodological and symbolic types…

  9. Does Advertising Pervert Higher Education? Is There a Case for Resistance?

    Science.gov (United States)

    Gibbs, Paul

    2007-01-01

    My argument is that when marketing-particularly advertising-may, under certain circumstances, work against the goals of autonomous, liberal higher education by undermining critical thinking and independent actions. This argument requires that advertising has a primary intent to persuade rather than inform; that by being intrusive, invasive and…

  10. Plasmid-mediated UV-protection in Streptococcus lactis

    Energy Technology Data Exchange (ETDEWEB)

    Chopin, M.C.; Rouault, A. (Institut National de la Recherche Agronomique, Rennes (France). Lab. de Recherches de Technologie Laitiere); Moillo-Batt, A. (Institut National de la Sante et de la Recherche Medicale (INSERM), Hopital de Pontchaillon, 35 - Rennes (France))

    1985-02-01

    Streptococcus lactis strain IL594 contains 9 plasmids, designated pIL1 to pIL9. On the basis of protoplast-induced curing experiments the authors showed that derivatives containing pIL7 were resistant to UV-irradiation while derivatives lacking pIL7 were sensitive. The pIL7-determined UV-protection was confirmed by co-transfer of the plasmid and of the character into a plasmid-free derivative of S. lactis IL594. Moreover, prophage induction required higher UV-fluence in this derivative carrying pIL7 than in the plasmid-free strain. This is the first report of a plasmid-mediated UV-protection in group N streptococci.

  11. Biological and medical effects of UV radiation on human health

    International Nuclear Information System (INIS)

    Piazena, H.

    1994-01-01

    Effecsts of UV radiation on human health are discussed. UV radiation is taken up through the skin and eyes. In the case of the eyes, the only known effects are damaging ones (e.g. cataracts). Irradiation of the skin, on the other hand, may either have a prophylactic and therapeutic effect or cause health problems if the exposure is too frequent and/or the dose too high. Positive effects are: Stimulation of the vitamin-D-3 synthesis and the autoimmune system, economisation of blood circulation, higher fitness, and the development of a UV protection system in the skin. Negative effects are: UV erythema, disturbances of the unspecific resistance and the immune system, and photocarcinogenesis. (orig.) [de

  12. Plasmid-mediated UV-protection in Streptococcus lactis

    International Nuclear Information System (INIS)

    Chopin, M.-C.; Rouault, A.

    1985-01-01

    Streptococcus lactis strain IL594 contains 9 plasmids, designated pIL1 to pIL9. On the basis of protoplast-induced curing experiments the authors showed that derivatives containing pIL7 were resistant to UV-irradiation while derivatives lacking pIL7 were sensitive. The pIL7-determined UV-protection was confirmed by cotransfer of the plasmid and of the character into a plasmid-free derivative of S. lactis IL594. Moreover, prophage induction required higher UV-fluence in this derivative carrying pIL7 than in the plasmid-free strain. This is the first report of a plasmid-mediated UV-protection in group N streptococci. (orig.)

  13. Higher taxa as surrogates of species richness of spiders in insect-resistant transgenic rice

    Institute of Scientific and Technical Information of China (English)

    Sheng Lin; Min-Sheng You; Liette Vasseur; Guang Yang; Feng-Jing Liu; Feng Guo

    2012-01-01

    Biodiversity assessments can often be time- and resource-consuming.Several alternative approaches have been proposed to reduce sampling efforts,including indicator taxa and surrogates.In this study,we examine the reliability of higher taxon surrogates to predict species richness in two experimental rice fields of Fujian Province,southeastern China during 2005 and 2009.Spider samples in transgenic and nontransgenic plots were collected using a suction sampler.Both the genus and family surrogates had significant and positive linear relationships with species richness in the transgenic and nontransgenic rice fields.The rice varieties did not significantly influence the linear relationships.Our findings suggest that higher-taxon surrogacy could be a useful alternative to complete species inventory for risk assessments of transgenic rice.

  14. Pairwise and higher-order correlations among drug-resistance mutations in HIV-1 subtype B protease

    Directory of Open Access Journals (Sweden)

    Morozov Alexandre V

    2009-08-01

    Full Text Available Abstract Background The reaction of HIV protease to inhibitor therapy is characterized by the emergence of complex mutational patterns which confer drug resistance. The response of HIV protease to drugs often involves both primary mutations that directly inhibit the action of the drug, and a host of accessory resistance mutations that may occur far from the active site but may contribute to restoring the fitness or stability of the enzyme. Here we develop a probabilistic approach based on connected information that allows us to study residue, pair level and higher-order correlations within the same framework. Results We apply our methodology to a database of approximately 13,000 sequences which have been annotated by the treatment history of the patients from which the samples were obtained. We show that including pair interactions is essential for agreement with the mutational data, since neglect of these interactions results in order-of-magnitude errors in the probabilities of the simultaneous occurence of many mutations. The magnitude of these pair correlations changes dramatically between sequences obtained from patients that were or were not exposed to drugs. Higher-order effects make a contribution of as much as 10% for residues taken three at a time, but increase to more than twice that for 10 to 15-residue groups. The sequence data is insufficient to determine the higher-order effects for larger groups. We find that higher-order interactions have a significant effect on the predicted frequencies of sequences with large numbers of mutations. While relatively rare, such sequences are more prevalent after multi-drug therapy. The relative importance of these higher-order interactions increases with the number of drugs the patient had been exposed to. Conclusion Correlations are critical for the understanding of mutation patterns in HIV protease. Pair interactions have substantial qualitative effects, while higher-order interactions are

  15. The tail of two models: Impact of circularity and biomass non-homogeneity on UV disinfection of wastewater flocs.

    Science.gov (United States)

    Azimi, Y; Liu, Y; Tan, T C; Allen, D G; Farnood, R R

    2017-12-01

    The effects of floc structural characteristics, i.e. shape and dense biomass distribution, were evaluated on ultraviolet (UV) disinfection resistance, represented by the tailing level of the UV dose response curve (DRC). Ellipsoid-shaped flocs of similar volume and different projected circularities were constructed in-silico and a mathematical model was developed to compare their UV DRC tailing levels (indicative of UV-resistance). It was found that floc shape can significantly influence tailing level, and rounder flocs (i.e. flocs with higher circularity) were more UV-resistant. This result was confirmed experimentally by obtaining UV DRCs of two 75-90 μm floc populations with different percentages (20% vs. 30%) of flocs with circularities higher than 0.5. The population enriched in less circular flocs (i.e. 20% flocs with circularities >0.5) had a lower tailing level (at least by 1-log) compared to the other population. The second model was developed to describe variations in UV disinfection kinetics observed in flocs with transverse vs. radial biomass non-homogeneity, indicative of biofilm-originated vs. suspended flocs. The varied-density hemispheres model and shell-core model were developed to simulate transverse and radial non-homogeneity, respectively. The UV DRCs were mathematically constructed and biofilm-originated flocs showed higher UV resistance compared to suspended flocs. The calculated UV DRCs agreed well with the experimental data collected from activated sludge and trickling filter flocs (no fitting parameters were used). These findings provide useful information in terms of designing/modifying upstream processes for reducing UV disinfection energy demand. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. UV-indeks og dets betydning

    DEFF Research Database (Denmark)

    Wulf, Hans Christian; Eriksen, Paul

    2010-01-01

    The published UV index refers to the expected UV intensity at mid day, when the solar elevation is at its maximum. In Scandinavia, the maximum UV index is seven around midsummer. When the UV index is three, the erythema-weighted dose will be three Standard Erythema Dose (SED) in the hour with max...... a sunburn already when the UV index is higher than two....

  17. A higher score on the Aging Males' Symptoms scale is associated with insulin resistance in middle-aged men.

    Science.gov (United States)

    Hamanoue, Nobuya; Tanabe, Makito; Tanaka, Tomoko; Akehi, Yuko; Murakami, Junji; Nomiyama, Takashi; Yanase, Toshihiko

    2017-05-30

    An age-associated androgen decrease and its pathological conditions are defined as late-onset hypogonadism (LOH). Among the various symptoms associated with LOH, a visceral fat increase is strongly associated with relatively low levels of testosterone. However, few studies have investigated the relationship between the Aging Males' Symptoms (AMS) scores and metabolic abnormalities. Thus, we aimed to clarify this relationship by investigating the relationship between AMS scores and various markers in blood. During routine health examinations in 241 middle-aged males (52.7±7.5 years of age, mean±SD), 150 males (62.2%) displayed higher AMS values than normal. No statistical association was observed between total AMS scores and any testosterone value. All mental, physical and sexual AMS subscales were significantly positively correlated with insulin levels and HOMA-IR. Only sexual subscale scores were significantly inversely associated with free or bioavailable testosterone level. Males with insulin resistance (HOMA-IR≥2.5) demonstrated significantly higher AMS scores than those with normal insulin sensitivity (HOMA-IRinsulin and HOMA-IR values. Interestingly, univariate and multivariate analyses revealed that HOMA-IR≥2.5 was a significant predictor for detection of moderately severe AMS values (AMS≥37), whereas AMS≥37 was not a predictor of metabolic syndrome by International Diabetes Federation (IDF) criterion. In conclusion, almost 60% of healthy male subjects displayed abnormal AMS scores. AMS values were not associated with testosterone values but rather were related to insulin resistance, particularly in subjects with moderately severe AMS values. Insulin resistance-related general unwellness might be reflected by AMS values.

  18. UV curable materials development

    Energy Technology Data Exchange (ETDEWEB)

    Parker, B.G.

    1996-12-01

    Adhesives, coatings, and inks were selected for evaluation based on literature search and possible production applications. A differential photocalorimeter was used to measure degree of cure and allow prediction of optimum processing conditions. UV cure equipment were characterized and the ability to size equipment to specific materials cure needs established. Adhesion tests procedures were developed for the adhesives and solvent resistance testing procedures developed for the coatings and inks.

  19. UV radiation hardness of silicon inversion layer solar cells

    International Nuclear Information System (INIS)

    Hezel, R.

    1990-01-01

    For full utilization of the high spectral response of inversion layer solar cells in the very-short-wavelength range of the solar spectrum sufficient ultraviolet-radiation hardness is required. In addition to the charge-induced passivation achieved by cesium incorporation into the silicon nitride AR coating, in this paper the following means for further drastic reduction of UV light-induced effects in inversion layer solar cells without encapsulation are introduced and interpretations are given: increasing the nitride deposition temperature, silicon surface oxidation at low temperatures, and texture etching and using higher substrate resistivities. High UV radiation tolerance and improvement of the cell efficiency could be obtained simultaneously

  20. Higher HOMA-IR index and correlated factors of insulin resistance in patients with IgA nephropathy.

    Science.gov (United States)

    Yang, Yue; Wei, Ri-Bao; Wang, Yuan-da; Zhang, Xue-Guang; Rong, Na; Tang, Li; Chen, Xiang-Mei

    2012-11-01

    To investigate the index of homeostasis model of insulin resistance (HOMA-IR) in IgA nephropathy (IgAN) patients, and to explore the possible correlated factors contributing to insulin resistance (IR) within these patients. There were 255 IgAN patients and 45 membranous nephropathy (MN) patients in our database. We identified 89 IgAN subjects and 21 MN subjects without diabetes and undergoing glucocorticoid therapy for at least 6 months. Data regarding physical examination, blood chemistry and renal pathology were collected from 89 IgAN subjects and 21 MN subjects. Then 62 IgAN patients and 19 MN patients with chronic kidney disease (CKD) Stage 1 - 2 were selected for the comparison of HOMA-IR index, 89 IgAN patients were selected for multiple regression analysis to test for correlated factors of HOMA-IR index with IgAN patients. Comparison between IgAN and MN show that HOMA-IR index was significantly higher in IgAN patients with CKD Stage 1 - 2. After logarithmic transformation with urine protein (UPr), Ln(UPr) (b = 0.186, p = 0.008), eGFR (b = -0.005, p = 0.014), > 50% of glomeruli with mesangial hypercellularity (b = 0.285, p = 0.027) and body mass index (BMI) (b = 0.039, p = 0.008) were correlated factors of HOMA-IR index in the multiple regression analysis. IgAN patients had higher HOMA-IR index compared with MN in the stages of CKD 1 - 2. For IgAN patients, more UPr, lower eGFR, > 50% of glomeruli with mesangial hypercellularity and higher BMI were correlated with IR.

  1. Light scattering on PHA granules protects bacterial cells against the harmful effects of UV radiation.

    Science.gov (United States)

    Slaninova, Eva; Sedlacek, Petr; Mravec, Filip; Mullerova, Lucie; Samek, Ota; Koller, Martin; Hesko, Ondrej; Kucera, Dan; Marova, Ivana; Obruca, Stanislav

    2018-02-01

    Numerous prokaryotes accumulate polyhydroxyalkanoates (PHA) in the form of intracellular granules. The primary function of PHA is the storage of carbon and energy. Nevertheless, there are numerous reports that the presence of PHA granules in microbial cells enhances their stress resistance and fitness when exposed to various stress factors. In this work, we studied the protective mechanism of PHA granules against UV irradiation employing Cupriavidus necator as a model bacterial strain. The PHA-accumulating wild type strain showed substantially higher UV radiation resistance than the PHA non-accumulating mutant. Furthermore, the differences in UV-Vis radiation interactions with both cell types were studied using various spectroscopic approaches (turbidimetry, absorption spectroscopy, and nephelometry). Our results clearly demonstrate that intracellular PHA granules efficiently scatter UV radiation, which provides a substantial UV-protective effect for bacterial cells and, moreover, decreases the intracellular level of reactive oxygen species in UV-challenged cells. The protective properties of the PHA granules are enhanced by the fact that granules specifically bind to DNA, which in turn provides shield-like protection of DNA as the most UV-sensitive molecule. To conclude, the UV-protective action of PHA granules adds considerable value to their primary storage function, which can be beneficial in numerous environments.

  2. Degradation of sulfamethoxazole by UV, UV/H2O2 and UV/persulfate (PDS): Formation of oxidation products and effect of bicarbonate.

    Science.gov (United States)

    Yang, Yi; Lu, Xinglin; Jiang, Jin; Ma, Jun; Liu, Guanqi; Cao, Ying; Liu, Weili; Li, Juan; Pang, Suyan; Kong, Xiujuan; Luo, Congwei

    2017-07-01

    The frequent detection of sulfamethoxazole (SMX) in wastewater and surface waters gives rise of concerns about their ecotoxicological effects and potential risks to induce antibacterial resistant genes. UV/hydrogen peroxide (UV/H 2 O 2 ) and UV/persulfate (UV/PDS) advanced oxidation processes have been demonstrated to be effective for the elimination of SMX, but there is still a need for a deeper understanding of product formations. In this study, we identified and compared the transformation products of SMX in UV, UV/H 2 O 2 and UV/PDS processes. Because of the electrophilic nature of SO 4 - , the second-order rate constant for the reaction of sulfate radical (SO 4 - ) with the anionic form of SMX was higher than that with the neutral form, while hydroxyl radical (OH) exhibited comparable reactivity to both forms. The direct photolysis of SMX predominately occurred through cleavage of the NS bond, rearrangement of the isoxazole ring, and hydroxylation mechanisms. Hydroxylation was the dominant pathway for the reaction of OH with SMX. SO 4 - favored attack on NH 2 group of SMX to generate a nitro derivative and dimeric products. The presence of bicarbonate in UV/H 2 O 2 inhibited the formation of hydroxylated products, but promoted the formation of the nitro derivative and the dimeric products. In UV/PDS, bicarbonate increased the formation of the nitro derivative and the dimeric products, but decreased the formation of the hydroxylated dimeric products. The different effect of bicarbonate on transformation products in UV/H 2 O 2 vs. UV/PDS suggested that carbonate radical (CO 3 - ) oxidized SMX through the electron transfer mechanism similar to SO 4 - but with less oxidation capacity. Additionally, SO 4 - and CO 3 - exhibited higher reactivity to the oxazole ring than the isoxazole ring of SMX. Ecotoxicity of transformation products was estimated by ECOSAR program based on the quantitative structure-activity relationship analysis as well as by experiments using

  3. Surface properties of UV irradiated PC–TiO{sub 2} nanocomposite film

    Energy Technology Data Exchange (ETDEWEB)

    Jaleh, B., E-mail: bkjaleh@yahoo.com; Shahbazi, N.

    2014-09-15

    Highlights: • Production of PC–TiO{sub 2} nanocomposite films. • Fully characterization of PC–TiO{sub 2} nanocomposite films. • Influence of UV irradiation on surface properties and hardness of PC–TiO{sub 2} nanocomposite film. - Abstract: In this work, polycarbonate–TiO{sub 2} nanocomposite films were prepared with two different percentages. The structure of samples were studied by X-ray diffraction. Thermal stability of the nanocomposites was studied by thermogravimetric analysis (TGA). The polycarbonate and polycarbonate–TiO{sub 2} nanocomposite films were exposed by UV light at different irradiation times. The effects of UV irradiation on the surface properties of samples have been studied by different characterization techniques, viz. scanning electron microscopy (SEM), FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurement and Vickers microhardness tester. Hydrophilicity and surface energy of UV treated samples varied depending on UV irradiation time. TGA curves showed that nanocomposite films have higher resistance to thermal degradation compared to polycarbonate. XPS analysis shows that surface of samples become more oxidized due to UV irradiation. For nanocomposite film, the smallest contact angle was observed in association with the longest UV irradiation time. The contact angle significantly decreased from 90° to 12° after 15 h of UV irradiation. It is observed that the hardness of the nanocomposite films increases after UV irradiation.

  4. Asian Adolescents with Excess Weight are at Higher Risk for Insulin Resistance than Non-Asian Peers.

    Science.gov (United States)

    Elsamadony, Ahmed; Yates, Kathy F; Sweat, Victoria; Yau, Po Lai; Mangone, Alex; Joseph, Adriana; Fierman, Arthur; Convit, Antonio

    2017-11-01

    The purpose of this study was to evaluate whether Asian American adolescents have higher metabolic risk from excess weight than non-Asians. Seven hundred thirty-three students, aged 14 to 19 years old, completed a school-based health screening. The 427 Asian and 306 non-Asian students were overall equivalent on age, sex, and family income. Height, weight, waist circumference, percent body fat, and blood pressure were measured. Fasting triglycerides, high- and low-density lipoproteins, glucose, and insulin levels were measured. Asian and non-Asians in lean or overweight/obesity groups were contrasted on the five factors that make up the metabolic syndrome. Asian adolescents carrying excess weight had significantly higher insulin resistance (IR), triglyceride levels, and waist-height ratios (W/H), despite a significantly lower overall BMI than corresponding non-Asians. Similarly, Asians had a stronger relationship between W/H and the degree of IR than non-Asian counterparts; 35% and 18% of the variances were explained (R 2  = 0.35, R 2  = 0.18) respectively, resulting in a significant W/H by racial group interaction (F change [1,236] = 11.56, P Asians have higher IR and triglyceride levels from excess weight than their non-Asian counterparts. One-size-fits-all public health policies targeting youth should be reconsidered and attention paid to Asian adolescents, including those with mild degrees of excess weight. © 2017 The Obesity Society.

  5. RKIP inhibition in cervical cancer is associated with higher tumor aggressive behavior and resistance to cisplatin therapy.

    Directory of Open Access Journals (Sweden)

    Olga Martinho

    Full Text Available Cervical cancer is one of the most common cancers in women worldwide, being high-risk group the HPV infected, the leading etiological factor. The raf kinase inhibitory protein (RKIP has been associated with tumor progression and metastasis in several human neoplasms, however its role on cervical cancer is unclear. In the present study, 259 uterine cervix tissues, including cervicitis, cervical intraepithelial lesions and carcinomas, were analyzed for RKIP expression by immunohistochemistry. We found that RKIP expression was significantly decreased during malignant progression, being highly expressed in non-neoplastic tissues (54% of the samples; 73/135, and expressed at low levels in the cervix invasive carcinomas (∼15% (19/124. Following in vitro downregulation of RKIP, we observed a viability and proliferative advantage of RKIP-inhibited cells over time, which was associated with an altered cell cycle distribution and higher colony number in a colony formation assay. An in vitro wound healing assay showed that RKIP abrogation is associated with increased migratory capability. RKIP downregulation was also associated with an increased vascularization of the tumors in vivo using a CAM assay. Furthermore, RKIP inhibition induced cervical cancer cells apoptotic resistance to cisplatin treatment. In conclusion, we described that RKIP protein is significantly depleted during the malignant progression of cervical tumors. Despite the lack of association with patient clinical outcome, we demonstrate, in vitro and in vivo, that loss of RKIP expression can be one of the factors that are behind the aggressiveness, malignant progression and chemotherapy resistance of cervical cancer.

  6. Dose effect of the uvsA+ gene product in duplication strains of Aspergillus nidulans

    International Nuclear Information System (INIS)

    Majerfeld, I.H.; Roper, J.A.

    1978-01-01

    Strains of Aspergillus nidulans which carry a particular segment of chromosome I in duplicate - one segment in normal position, the other translocated to chromosome II - are more resistant to uv light than are strains with a balanced haploid genome. A double dose of the uvsA + allele, carried on the duplicate segment, determines this enhanced resistance; this is shown by the descending order of resistance of duplication haploids uvsA + /uvsA + , uvsA1/uvsA + and uvsA1/uvsA1. An unbalanced diploid with three doses of the uvsA + allele also shows greater resistance than a balanced uvsA + //uvsA + diploid. However, in balanced diploids the uvsA1 allele appears to be completely recessive; uvsA + //uvsA + and uvsA + //uvsA1 diploids produce indistinguishable survival curves after uv irradiation. Thus, the uvsA + gene product is not rate-limiting in repair processes in strains with a balanced genome. The rate-limiting effect observed in these unbalanced strains presumably reflects an interaction of the uvsA + product and other functions determined by the rest of the genome. Duplication haploids and normal haploids lose photorepairable lesions at similar rates. This observation may be interpreted to indicate that differences in survival are not due to differences in the efficiency of excision of uv-induced pyrimidime dimers

  7. Durable diamond-like carbon templates for UV nanoimprint lithography

    International Nuclear Information System (INIS)

    Tao, L; Ramachandran, S; Nelson, C T; Overzet, L J; Goeckner, M; Lee, G; Hu, W; Lin, M; Willson, C G; Wu, W

    2008-01-01

    The interaction between resist and template during the separation process after nanoimprint lithography (NIL) can cause the formation of defects and damage to the templates and resist patterns. To alleviate these problems, fluorinated self-assembled monolayers (F-SAMs, i.e. tridecafluoro-1,1,2,2,tetrahydrooctyl trichlorosilane or FDTS) have been employed as template release coatings. However, we find that the FDTS coating undergoes irreversible degradation after only 10 cycles of UV nanoimprint processes with SU-8 resist. The degradation includes a 28% reduction in surface F atoms and significant increases in the surface roughness. In this paper, diamond-like carbon (DLC) films were investigated as an alternative material not only for coating but also for direct fabrication of nanoimprint templates. DLC films deposited on quartz templates in a plasma enhanced chemical vapor deposition system are shown to have better chemical and physical stability than FDTS. After the same 10 cycles of UV nanoimprints, the surface composition as well as the roughness of DLC films were found to be unchanged. The adhesion energy between the DLC surface and SU-8 is found to be smaller than that of FDTS despite the slightly higher total surface energy of DLC. DLC templates with 40 nm features were fabricated using e-beam lithography followed by Cr lift-off and reactive ion etching. UV nanoimprinting using the directly patterned DLC templates in SU-8 resist demonstrates good pattern transfer fidelity and easy template-resist separation. These results indicate that DLC is a promising material for fabricating durable templates for UV nanoimprint lithography

  8. Inactivation of microorganisms by UV-treatment of must and wine

    Directory of Open Access Journals (Sweden)

    Durner Dominik

    2017-01-01

    Full Text Available The objective was to investigate the applicability of UV-C technology to inactivate yeasts and bacteria in must and wine. Experiments were carried out in vintage 2016 with Riesling musts of different quality containing their natural microflora. Yeasts were tested more resistant to UV-C energy than bacteria. Saccharomyces cerevisiae showed higher tolerance against UV-C irradiation than Hanseniaspora uvarum facilitating new opportunities to control spontaneous fermentations. However, inactivation efficacy was strongly dependent on turbidity of musts and the initial degree of contamination suggesting a shadowing effect of individual germs. Compared with thermal pasteurization, UV-C treatment of must with 1 kJ/L showed similar effects in germ-reduction. While thermal pasteurization significantly decreased aroma precursors in musts, UV-C treatment did not change concentrations of glycosidically-bound C6-alcohols, monoterpenes and C13-norisoprenoids as shown by GC-MS analysis. Applying UV-C technology in wines, it was possible to irreversibly stop ongoing alcoholic fermentation indicating that UV-C treatment is capable to replace SO2 addition to produce wines with residual sugar. Besides inactivation power, UV-C is known for its ability to form powerful off-flavours such as methional or methanethiol. Sensory analysis revealed that the application of UV-C at doses < 2 kJ/L in must is uncritical. However, applying UV-C after alcoholic fermentation can result in rising concentrations of mercaptans already at doses < 1 kJ/L. In this context, compounds such as caftaric acid, riboflavin and dissolved oxygen are thought to positively contribute to the UV-induced formation of off-flavours in wine.

  9. COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

    Directory of Open Access Journals (Sweden)

    О. Міхєєв

    2011-04-01

    Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

  10. Higher levels of Zidovudine resistant HIV in the colon compared to blood and other gastrointestinal compartments in HIV infection

    Directory of Open Access Journals (Sweden)

    van Marle Guido

    2010-09-01

    Full Text Available Abstract Background The gut-associated lymphoid tissue (GALT is the largest lymphoid organ infected by human immunodeficiency virus type 1 (HIV-1. It serves as a viral reservoir and host-pathogen interface in infection. This study examined whether different parts of the gut and peripheral blood lymphocytes (PBL contain different drug-resistant HIV-1 variants. Methods Gut biopsies (esophagus, stomach, duodenum and colon and PBL were obtained from 8 HIV-1 infected preHAART (highly active antiretroviral therapy patients at three visits over 18 months. Patients received AZT, ddI or combinations of AZT/ddI. HIV-1 Reverse transcriptase (RT-coding sequences were amplified from viral DNA obtained from gut tissues and PBL, using nested PCR. The PCR fragments were cloned and sequenced. The resulting sequences were subjected to phylogenetic analyses, and antiretroviral drug mutations were identified. Results Phylogenetic and drug mutation analyses revealed differential distribution of drug resistant mutations in the gut within patients. The level of drug-resistance conferred by the RT sequences was significantly different between different gut tissues and PBL, and varied with antiretroviral therapy. The sequences conferring the highest level of drug-resistance to AZT were found in the colon. Conclusion This study confirms that different drug-resistant HIV-1 variants are present in different gut tissues, and it is the first report to document that particular gut tissues may select for drug resistant HIV-1 variants.

  11. Transfer of human genes conferring resistance to methylating mutagens, but not to UV irradiation and cross-linking agents, into Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Kaina, B.; Van Zeeland, A.A.; Backendorf, C.; Thielmann, H.W.; Van de Putte, P.

    1987-01-01

    Chinese hamster ovary cells were transfected by human DNA ligated to the bacterial gpt (xanthine-guanine-phosphoribosyltransferase) gene which was used either in its native form or after partial inactivation with methylnitrosourea. The gpt+ transfectants were screened for resistance to high doses of N-methyl-N'-nitro-N-nitrosoguanidine. Using this approach, we showed that Chinese hamster ovary cells can acquire N-methyl-N'-nitro-N-nitrosoguanidine resistance upon transfection with DNA from diploid human fibroblasts, that this resistance is transferable by secondary transfection and is specific for methylating mutagens, and that it is not caused by increased removal of O6-methylguanine, 3-methyladenine, and 7-methylguanine from DNA

  12. Extremophilic Acinetobacter Strains from High-Altitude Lakes in Argentinean Puna: Remarkable UV-B Resistance and Efficient DNA Damage Repair

    Science.gov (United States)

    Albarracín, Virginia Helena; Pathak, Gopal P.; Douki, Thierry; Cadet, Jean; Borsarelli, Claudio Darío; Gärtner, Wolfgang; Farias, María Eugenia

    2012-06-01

    High-Altitude Andean Lakes (HAAL) of the South American Andes are almost unexplored ecosystems of shallow lakes. The HAAL are recognized by a remarkably high UV exposure, strong changes in temperature and salinity, and a high content of toxic elements, especially arsenic. Being exposed to remarkably extreme conditions, they have been classified as model systems for the study of life on other planets. Particularly, Acinetobacter strains isolated from the HAAL were studied for their survival competence under strong UV-B irradiation. Clinical isolates, Acinetobacter baumannii and Acinetobacter johnsonii, served as reference material. Whereas the reference strains rapidly lost viability under UV-B irradiation, most HAAL-derived strains readily survived this exposure and showed less change in cell number after the treatment. Controls for DNA repair activity, comparing dark repair (DR) or photo repair (PR), gave evidence for the involvement of photolyases in the DNA repair. Comparative measurements by HPLC-mass spectrometry detected the number of photoproducts: bipyrimidine dimers under both PR and DR treatments were more efficiently repaired in the HAAL strains (up to 85 % PR and 38 % DR) than in the controls (31 % PR and zero DR ability). Analysis of cosmid-cloned total genomic DNA from the most effective DNA-photorepair strain (Ver3) yielded a gene (HQ443199) encoding a protein with clear photolyase signatures belonging to class I CPD-photolyases. Despite the relatively low sequence similarity of 41 % between the enzymes from Ver3 and from E. coli (PDB 1DNPA), a model-building approach revealed a high structural homology to the CPD-photolyase of E. coli.

  13. Role of recombination in repair and UV-mutagenesis in Saccharomyces cerevisiae : studies with mutants defective in X-ray and UV-induced intragenic mitotic recombination

    International Nuclear Information System (INIS)

    Vashishat, R.K.; Kakar, S.N.

    1977-01-01

    In order to study the role of recombination in repair of radiation damage and damage caused by chemical mutagens, studies were conducted on two recombination deficient strains 2c r(rec 5) and 2c 8(rec 4) isolated from Z140-51C. These strains are disomic for chromosome VIII and defective in X-ray and UV-induced intragenic mitotic recombination. The strain 2c 4 was sensitive to UV, HNO 2 , EMS and NG but it was as resistant to X-rays as the wild-type strain. Strain 2c 8 was sensitive to NG and showed more or less wild-type resistance to other mutagens. All the strains showed a decrease in UV-survival when caffeine (1g/1) was present in the post-irradiation medium. There was an increase in viability by photoreactivation. A comparison of UV-induced reversion at ade 2 and his 5 loci in rec strains and parental strain showed that total frequency of UV-induced revertants for ade 2 in all the strains was less than that for his 5. The frequency of total revertants for ade 2 was same in wild-type and 2c 8 but it was higher for his 5 in strain 2c 8. The total frequency of UV-induced revertants for both loci was less in 2c 4 as compared to wild-type. It is concluded that recombination is involved in repair of damage caused by UV light and chemical mutagens and in UV-induced mutations. (author)

  14. The metabolic syndrome is associated with a higher resistance to intravenous thrombolysis for acute ischemic stroke in women than in men.

    Science.gov (United States)

    Arenillas, Juan F; Sandoval, Patricio; Pérez de la Ossa, Natalia; Millán, Mónica; Guerrero, Cristina; Escudero, Domingo; Dorado, Laura; López-Cancio, Elena; Castillo, José; Dávalos, Antoni

    2009-02-01

    The metabolic syndrome (MetS) might confer a higher resistance to intravenous thrombolysis in acute middle cerebral artery (MCA) ischemic stroke. MetS increases the risk of stroke in women to a greater extent than in men. We aimed to investigate whether there might be sex differences in the impact of MetS on the response to intravenous thrombolysis for acute MCA ischemic stroke. We prospectively studied consecutive ischemic stroke patients, treated with intravenous tissue-type plasminogen activator according to SITS-MOST criteria, with an MCA occlusion on prebolus transcranial Doppler examination. Resistance to thrombolysis was defined as the absence of complete MCA recanalization 24 hours after tissue-type plasminogen activator infusion by transcranial Doppler criteria. MetS was diagnosed according to the criteria established by the American Heart Association/National Heart, Lung, and Blood Institute 2005 statement. A total of 125 patients (75 men, 50 women; mean age, 67.6+/-11 years) were included. MetS was diagnosed in 76 (61%) patients. Resistance to clot lysis at 24 hours was observed in 53 (42%) patients. Two multivariate-adjusted, logistic-regression models identified that MetS was associated with a higher resistance to tissue-type plasminogen activator, independently of other significant baseline variables (odds ratio=9.8; 95% CI, 3.5 to 27.8; P=0.0001) and of the individual components of the MetS. The MetS was associated with a significantly higher odds of resistance to thrombolysis in women (odds ratio=17.5; 95% CI, 1.9 to 163.1) than in men (odds ratio=5.1; 95% CI, 1.6 to 15.6; P for interaction=0.0004). The effect of MetS on the resistance to intravenous thrombolysis for acute MCA ischemic stroke appears to be more pronounced in women than in men.

  15. Effects of a tumor promoter and an anti-promoter on spontaneous and UV-induced 6-thioguanine-resistant mutations and sister-chromatid exchanges in V79 Chinese hamster cells

    International Nuclear Information System (INIS)

    Fujiwara, Y.; Kano, Y.; Tatsumi, M.; Paul, P.

    1980-01-01

    The effects of a tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and/or an anti-promoter antipain (protease inhibitor) on spontaneous and ultraviolet-induced sister-chromatid exchanges (SCEs) and 6-thioguanine-resistant (6TGsup(r)) recessive mutations were examined in V79 Chinese hamster cells in culture. TPA and/or antipain neither significantly altered base-line and UV-induced immediate SCE frequencies, nor decreased the level of delayed SCEs which persisted 6-7 days after irradiation. TPA and/or antipain appeared to enhance the recovery of UV-induced 6TGsup(r) colonies at the plateau expression phase despite non-mutagenicity by themselves and unaltered metabolic cooperation. Thus, the results conceivably imply that the 6TGsup(r)-recessive mutation expression, but not fixation, can be modulated at the cell level by TPA and/or antipain. Our results, together with the recent results of Loveday and Latt, may argue against the notion that TPA enhances the antipain-suppressible SCEs as an index of mitotic recombination in relevance with a tumor-promotion mechanism. (orig.)

  16. Silane effects on the surface morphology and abrasion resistance of transparent SiO2/UV-curable resin nano-composites

    International Nuclear Information System (INIS)

    Hsiang, Hsing-I.; Chang, Yu-Lun; Chen, Chi-Yu; Yen, Fu-Su

    2011-01-01

    Transparent ultraviolet curable nano-composite coatings consisting of nano-sized SiO 2 and acrylate resin have been developed to improve the abrasion resistance of organic polymers. The nano-sized SiO 2 particles were surface-modified using various amounts of 3-methacryloxypropyltrimethoxysilane. The 3-methacryloxypropyltrimethoxysilane concentration effects on the surface morphology and abrasion resistance of the transparent SiO 2 /ultraviolet-curable resin nano-composites were investigated using scanning electron microscopy, atomic force microscopy, and ultraviolet-visible spectrophotometer. The results showed that as the 3-methacryloxypropyltrimethoxysilane/SiO 2 weight ratio increased from 0.2 to 0.6, the dispersion, compatibility and cross-linking density between the 3-methacryloxypropyltrimethoxysilane-modified SiO 2 particles and acrylate resin were improved, leading to an increase in abrasion resistance. However, as the 3-methacryloxypropyltrimethoxysilane/SiO 2 weight ratio was increased to 1.5, the additional 3-methacryloxypropyltrimethoxysilane may exceed that needed to fill the pores with the probability of SiO 2 nano-particles existing on the coating surface was lower than that for samples with a 3-methacryloxypropyltrimethoxysilane/SiO 2 weight ratio of 0.6. This produced a decrease in abrasion resistance.

  17. UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

    Directory of Open Access Journals (Sweden)

    Alyaa M. Zyara

    2017-01-01

    Full Text Available UV-LEDs are a new method of disinfecting drinking water. Some viruses are very resistant to UV and the efficiency of UV-LEDs to disinfect them needs to be studied. Drinking water was disinfected with UV-LEDs after spiking the water with MS2 and four UV- and/or Cl-resistant coliphages belonging to RNA or DNA coliphages isolated from municipal wastewater. UV-LEDs operating at a wavelength of 270 nm for 2 min with 120 mW of irradiation caused 0.93–2.73 Log10-reductions of coliphages tested in a reactor of a 5.2 L volume. Irradiation time of 10 min in the same system increased the Log10-reductions to 4.30–5.16. Traditional mercury UV (Hg-UV lamp at a 254 nm wavelength caused 0.67–4.08 Log10-reductions in 2 min and 4.56–7.21 Log10-reductions in 10 min in 10 mL of water. All coliphages tested except MS2 achieved 4 Log10-reductions with UV-LEDs at a dose that corresponded to 70 mWs/cm2 using Hg-UV. Thus, UV-LEDs are a promising method of disinfecting UV- and/or Cl-resistant viruses.

  18. Patterning of nanoparticulate transparent conductive ITO films using UV light irradiation and UV laser beam writing

    International Nuclear Information System (INIS)

    Solieman, A.; Moharram, A.H.; Aegerter, M.A.

    2010-01-01

    Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency (∼85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ□.

  19. Evaluation of Joint Performance on High Nitrogen Stainless Steel Which is Expected to Have Higher Allergy Resistance

    Science.gov (United States)

    Nakano, Kouichi

    Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.

  20. Deinococcus frigens sp. nov., Deinococcus saxicola sp. nov., and Deinococcus marmoris sp. nov., low temperature and draught-tolerating, UV-resistant bacteria from continental Antarctica.

    Science.gov (United States)

    Hirsch, Peter; Gallikowski, Claudia A; Siebert, Jörg; Peissl, Klaus; Kroppenstedt, Reiner; Schumann, Peter; Stackebrandt, Erko; Anderson, Robert

    2004-11-01

    Six Gram-positive, non-motile, UV- and draught-tolerant bacteria were isolated from antarctic soil and rock samples. The pink to orange cocci grew well on oligotrophic medium PYGV (pH 7.5) at 9-18 degrees C. They tolerated 0-10% NaCl, were aerobic to facultatively anaerobic and contained ornithine in their cell wall (type A3beta, Orn-Gly2). The lipid profiles of four strains were found to be typical for those of D. radiodurans. Major fatty acids were 16:1cis9, 15:1cis9, 17:1cis9 and i17:1cis9, the respiratory quinone of three strains was MK-8. Comparative 16S rDNA gene sequencing revealed phylogenetic relationships to the Deinococcus clade, especially to D. radiopugnans. The levels of 16S rRNA gene sequence similarity and DNA-DNA hybridisation data showed the six isolates represented new taxa. Phenotypic properties supported the description of three new species which were different from the eight known Deinococcus species and particularly from D. radiopugnans. Soil isolate AA-692T (DSM 12807T) is the type strain of Deinococcus frigens sp. nov., with AA-752 (DSM 15993) and AA-829 (DSM 15994) as additional strains from soil. The endolithic isolate AA-1444T, Deinococcus saxicola sp. nov., (DSM 15974T) came from antarctic sandstone, and Deinococcus marmoris sp. nov. (isolate AA-63T [DSM 12784T]) as well as AA-69 (DSM 15951) were isolated from antarctic marble.

  1. The Higher the Insulin Resistance the Lower the Cardiac Output in Men with Type 1 Diabetes During the Maximal Exercise Test.

    Science.gov (United States)

    Niedzwiecki, Pawel; Naskret, Dariusz; Pilacinski, Stanislaw; Pempera, Maciej; Uruska, Aleksandra; Adamska, Anna; Zozulinska-Ziolkiewicz, Dorota

    2017-06-01

    The aim of this study was to assess the hemodynamic parameters analyzed in bioimpedance cardiography during maximal exercise in patients with type 1 diabetes differing in insulin resistance. The study group consisted of 40 men with type 1 diabetes. Tissue sensitivity to insulin was assessed on the basis of the glucose disposal rate (GDR) analyzed during hyperinsulinemic-euglycemic clamp. Patients were divided into groups with GDR insulin sensitivity) and GDR ≥4.5 mg/kg/min (G2 group-higher insulin sensitivity). During the exercise test, the heart rate, systolic volume, cardiac output, cardiac index were measured by the impedance meter (PhysioFlow). Compared with the G2 group, the G1 group had a lower cardiac output (CO): during exercise 8.6 (IQR 7.7-10.0) versus 12.8 (IQR 10.8-13.7) L/min; P insulin resistance is associated with cardiac hemodynamic parameters assessed during and after exercise. The higher the insulin resistance the lower the cardiac output during maximal exercise in men with type 1 diabetes.

  2. Índice UV

    Science.gov (United States)

    Información general sobre el Índice UV que proporciona un pronóstico del riesgo esperado de sobreexposición a la radiación ultravioleta (UV) del sol. El índice UV va acompañado de recomendaciones para protegerse del sol.

  3. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  4. Characterization of ZnO coated polyester fabrics for UV protection

    International Nuclear Information System (INIS)

    Broasca, G.; Borcia, G.; Dumitrascu, N.; Vrinceanu, N.

    2013-01-01

    The textile industry aims to develop fabrics adapted to environmental conditions, in particular to UV radiation. Taking into account the demand for such materials, we prepare an inorganic–organic material, based on ZnO microparticles impregnation of polyester textiles, to perform combined UV-protection properties and high hydrophobicity. Scanning electron microscopy, UV reflectance, Impedance Spectroscopy, contact angle, air permeability, resistance to vapor transfer and tensile strength measurement are used for analysis of the surface and volume properties, related to the performance of the material under environmental conditions, as UV radiation, water and water vapors. The impregnation method ensures a good homogeneity and dispersion of ZnO microparticles into the textile polymeric matrix. The optimum level of impregnation of the fabrics is established to 3–5% ZnO, yielding stable properties, without overloading the fabric. The response of the coated polymer indicates better absorbing the UV radiation and dissipating the surface charge, time stability against UV and higher hydrophobic character, without modification of the mechanical properties, offering enhanced performance and comfort under environmental conditions.

  5. UV-Induced Cell Death in Plants

    Science.gov (United States)

    Nawkar, Ganesh M.; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-01

    Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280–320 nm) and UV-A (320–390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD). PMID:23344059

  6. Cotton fabrics with UV blocking properties through metal salts deposition

    International Nuclear Information System (INIS)

    Emam, Hossam E.; Bechtold, Thomas

    2015-01-01

    Graphical abstract: - Highlights: • Introducing metal salt based UV-blocking properties into cotton fabric. • A quite simple technique used to produce wash resistant UV-absorbers using different Cu-, Zn- and Ti-salts. • Good UPF was obtained after treatment with Cu and Ti salts, and ranged between 11.6 and 14. • The efficiency of the deposited metal oxides is compared on molar basis. - Abstract: Exposure to sunlight is important for human health as this increases the resistance to diverse pathogens, but the higher doses cause skin problems and diseases. Hence, wearing of sunlight protective fabrics displays a good solution for people working in open atmosphere. The current study offered quite simple and technically feasible ways to prepare good UV protection fabrics based on cotton. Metal salts including Zn, Cu and Ti were immobilized into cotton and oxidized cotton fabrics by using pad-dry-cure technique. Metal contents on fabrics were determined by AAS; the highest metal content was recorded for Cu-fabric and it was 360.6 mmol/kg after treatment of oxidized cotton with 0.5 M of copper nitrate. Ti contents on fabrics were ranged between 168.0 and 200.8 mmol/kg and it showed the lowest release as only 38.1–46.4% leached out fabrics after five laundry washings. Metal containing deposits were specified by scanning electron microscopy and energy dispersive X-ray spectroscopy. UV-transmission radiation over treated fabrics was measured and ultraviolet protection factor (UPF) was calculated. UPF was enhanced after treatment with Cu and Ti salts to be 11.6 and 14, respectively. After five washings, the amount of metal (Cu or Ti) retained indicates acceptable laundering durability.

  7. Prevalence of Non-responders for Glucose Control Markers after 10 Weeks of High-Intensity Interval Training in Adult Women with Higher and Lower Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Cristian Álvarez

    2017-07-01

    Full Text Available Background: Exercise training improves performance and biochemical parameters on average, but wide interindividual variability exists, with individuals classified as responders (R or non-responders (NRs, especially between populations with higher or lower levels of insulin resistance. This study assessed the effects of high-intensity interval training (HIIT and the prevalence of NRs in adult women with higher and lower levels of insulin resistance.Methods: Forty adult women were assigned to a HIIT program, and after training were analyzed in two groups; a group with higher insulin resistance (H-IR, 40 ± 6 years; BMI: 29.5 ± 3.7 kg/m2; n = 20 and a group with lower insulin resistance (L-IR, 35 ± 9 years; 27.8 ± 2.8 kg/m2; n = 20. Anthropometric, cardiovascular, metabolic, and performance variables were measured at baseline and after 10 weeks of training.Results: There were significant training-induced changes [delta percent (Δ%] in fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR scores in the H-IR group (−8.8, −26.5, −32.1%, p < 0.0001, whereas no significant changes were observed in the L-IR. Both groups showed significant pre-post changes in other anthropometric variables [waist circumference (−5.2, p < 0.010, and −3.8%, p = 0.046 and tricipital (−13.3, p < 0.010, and −13.6%, p < 0.0001, supra-iliac (−19.4, p < 0.0001, and −13.6%, p < 0.0001, and abdominal (−18.2, p < 0.0001, and −15.6%, p < 0.010 skinfold measurements]. Systolic blood pressure decreased significantly only in the L-IR group (−3.2%, p < 0.010. Both groups showed significant increases in 1RMLE (+12.9, p < 0.010, and +14.7%, p = 0.045. There were significant differences in the prevalence of NRs between the H-IR and L-IR groups for fasting glucose (25 vs. 95%, p < 0.0001 and fasting insulin (p = 0.025 but not for HOMA-IR (25 vs. 45%, p = 0.185.Conclusion: Independent of the “magnitude” of the

  8. Lower adiponectin levels at first trimester of pregnancy are associated with increased insulin resistance and higher risk of developing gestational diabetes mellitus.

    Science.gov (United States)

    Lacroix, Marilyn; Battista, Marie-Claude; Doyon, Myriam; Ménard, Julie; Ardilouze, Jean-Luc; Perron, Patrice; Hivert, Marie-France

    2013-06-01

    To evaluate the associations between adiponectin levels and 1) the risk of developing gestational diabetes mellitus (GDM), and 2) insulin resistance/sensitivity, β-cell function, and compensation indices in a prospective cohort representative of the general population of pregnant women. We performed anthropometric measurements and collected blood samples at 1st (6-13 weeks) and 2nd (24-28 weeks) trimesters. Diagnosis of GDM was made at 2nd trimester based on a 75-g oral glucose tolerance test (International Association of the Diabetes and Pregnancy Study Groups criteria). Insulin was measured (ELISA; Luminex) to estimate homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-B), insulin sensitivity (Matsuda index), insulin secretion (AUC(insulin/glucose)), and β-cell compensation (insulin secretion sensitivity index-2). Adiponectin was measured by radioimmunoassay. Among the 445 participants included in this study, 38 women developed GDM. Women who developed GDM had lower 1st-trimester adiponectin levels (9.67 ± 3.84 vs. 11.92 ± 4.59 µg/mL in women with normal glucose tolerance). Lower adiponectin levels were associated with higher risk of developing GDM (OR, 1.12 per 1 µg/mL decrease of adiponectin levels; P = 0.02, adjusted for BMI and HbA1c at 1st trimester). Adiponectin levels at 1st and 2nd trimesters were associated with HOMA-IR (both: r = -0.22, P insulin/glucose). Pregnant women with lower adiponectin levels at 1st trimester have higher levels of insulin resistance and are more likely to develop GDM independently of adiposity or glycemic measurements.

  9. Dichotomy in response to indomethacin in uv-C and uv-B induced ultraviolet light inflammation

    International Nuclear Information System (INIS)

    Eaglstein, W.H.; Marsico, A.R.

    1975-01-01

    In subjects irradiated with both UV-C and UV-B ultraviolet light (UVL), 10 μg of intradermal indomethacin decreased the redness in all 13 of the UV-B irradiated areas but in only 2 of 13 of the UV-C irradiated areas. Higher doses of intradermal indomethacin (50 μg and 100 μg) decreased the redness produced by UV-C irradiation in 6 subjects. It is suggested that the failure of 10 μg of indomethacin to decrease the redness of the UV-C induced inflammation, while decreasing the redness in the UV-B induced inflammation, is consistent with the possibility that prostaglandins participate in UV-B but not UV-C induced inflammation

  10. Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain

    International Nuclear Information System (INIS)

    Yang, Zhen; Kong, Fanxiang; Shi, Xiaoli; Yu, Yang; Zhang, Min

    2015-01-01

    Highlights: • UV-B radiation showed higher inhibition to non-toxin producing than toxin-producing strains on growth and photosynthetic activity. • Both intracellular and extracellular MC contents decreased markedly under UV-B radiation. • Higher resistance to UV-B radiation helped toxin-producing M. aeruginosa to predominate in the competition. - Abstract: Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms

  11. Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhen, E-mail: zhyang@niglas.ac.cn; Kong, Fanxiang, E-mail: fxkong@niglas.ac.cn; Shi, Xiaoli; Yu, Yang; Zhang, Min

    2015-02-11

    Highlights: • UV-B radiation showed higher inhibition to non-toxin producing than toxin-producing strains on growth and photosynthetic activity. • Both intracellular and extracellular MC contents decreased markedly under UV-B radiation. • Higher resistance to UV-B radiation helped toxin-producing M. aeruginosa to predominate in the competition. - Abstract: Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms.

  12. Mutational synergism between p-fluorophenylalaline and UV in Coprinus lagopus

    International Nuclear Information System (INIS)

    Talmud, P.J.

    1977-01-01

    The amino acid analogue p-fluorophenylalanine (PFP) is mutagenic to Coprinus lagopus due to its incorporation into proteins. Spontaneous mutations, PFP and UV mutagenesis and PFP/UV synergism have been studied in a UV resistant strain and in two complementing UV sensitive mutant strains. By comparison to the UV resistant strain, one UV sensitive strain shows normal spontaneous mutations, 1.4% PFP-induced mutations and 50-fold UV mutagenesis. The second UV sensitive strain has 19-fold spontaneous mutation frequency and slightly elevated UV mutagenesis. In all 3 strains the PFP/UV synergism is comparable (4-5 times the arithmetic expected). The results indicate that PFP mutagenesis is due to the incorporation of PFP into enzymes normally functioning in the organism but which also participate in UV repair mechanisms. A model is proposed for UV repair which is based on a PFP sensitive excision repair system of at least two enzymes, an alternative 'error-proof' pathway which is not susceptible to PFP and an 'error-prone' pathway which is responsible for UV mutagenesis and is susceptible to PFP as shown by the PFP/UV synergism. Because PFP is given before UV treatment, this implies a UV inducible cofactor and a PFP sensitive enzyme which only functions after UV activation

  13. Evaluating the combined effects of pretilachlor and UV-B on two Azolla species.

    Science.gov (United States)

    Prasad, Sheo Mohan; Kumar, Sushil; Parihar, Parul; Singh, Anita; Singh, Rachana

    2016-03-01

    The present study assessed the comparative responses of two agronomic species of Azolla (A.microphylla and A. pinnata) exposed to man-made and natural stressors by evaluating biomass accumulation, pigments (chlorophyll a and b and carotenoid contents), photosynthetic activity and nitrogen metabolism. The study was carried out in field where two species of Azolla were cultured and treated with various concentrations (5, 10 and 20 μg ml(-1)) of herbicide; pretilachlor [2-chloro-2,6-diethyl-N-(2-propoxyethyl) acetanilide] and enhanced levels (UV-B1: ambient +2.2 kJ m(-2) day(-1) and UV-B2: ambient +4.4 kJ m(-2) day(-1)) of UV-B, alone as well as in combination. Biomass accumulation, photosynthetic pigments; chlorophyll a, b and carotenoids, photosynthetic oxygen yield and photosynthetic electron transport activities i.e. photosystem II (PS II) and photosystem I (PS I) in both the species declined with the increasing doses of pretilachlor and UV-B radiation, which further declined when applied in combination. The lower doses (5 and 10 μg ml(-1)) of pretilachlor and UV-B (UV-B1 and UV-B2) alone, damaged mainly the oxidation side of PS II, whereas higher dose (20 μg ml(-1)) of pretilachlor alone and in combination with UV-B1 and UV-B2 caused damage to PS II reaction centre and beyond this towards the reduction side. A significant enhancement in respiration was also noticed in fronds of both the Azolla species following pretilachlor and UV-B treatment, hence indicating strong damaging effect. The nitrate assimilating enzymes - nitrate reductase and nitrite reductase and ammonium assimilating enzymes - glutamine synthetase and glutamate synthase were also severely affected when treated either with pretilachlor and/or UV-B while glutamate dehydrogenase exhibited a stimulatory response. The study suggests that both the species of Azolla showed considerable damage under pretilachlor and UV-B treatments alone, however, in combination the effect was more intense. Further, in

  14. Higher Concentrations of BCAAs and 3-HIB Are Associated with Insulin Resistance in the Transition from Gestational Diabetes to Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Ulrika Andersson-Hall

    2018-01-01

    Full Text Available Aim. Determine the metabolic profile and identify risk factors of women transitioning from gestational diabetes mellitus (GDM to type 2 diabetes mellitus (T2DM. Methods. 237 women diagnosed with GDM underwent an oral glucose tolerance test (OGTT, anthropometrics assessment, and completed lifestyle questionnaires six years after pregnancy. Blood was analysed for clinical variables (e.g., insulin, glucose, HbA1c, adiponectin, leptin, and lipid levels and NMR metabolomics. Based on the OGTT, women were divided into three groups: normal glucose tolerance (NGT, impaired glucose tolerance (IGT, and T2DM. Results. Six years after GDM, 19% of subjects had T2DM and 19% IGT. After BMI adjustment, the IGT group had lower HDL, higher leptin, and higher free fatty acid (FFA levels, and the T2DM group higher triglyceride, FFA, and C-reactive protein levels than the NGT group. IGT and T2DM groups reported lower physical activity. NMR measurements revealed that levels of branched-chain amino acids (BCAAs and the valine metabolite 3-hydroxyisobyturate were higher in T2DM and IGT groups and correlated with measures of insulin resistance and lipid metabolism. Conclusion. In addition to well-known clinical risk factors, BCAAs and 3-hydroxyisobyturate are potential markers to be evaluated as predictors of metabolic risk after pregnancy complicated by GDM.

  15. UV-sensitivity and repair of UV-damage in Salmonella of wild type

    International Nuclear Information System (INIS)

    Kondratiev, Y.S.; Brukhansky, G.V.; Andreeva, I.V.; Skavronskaya, A.G.

    1977-01-01

    The UV-sensitivity of wild type Salmonella strains has been compared to that of wild type E.coli and its UV-sensitive mutants. Many wild type Salmonella strains are 4-5 times more sensitive than wild type E.coli and their inactivation curve is similar to that for E.coli with a mutation in the polA gene. Alkaline sucrose gradient centrifugation has shown a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a Salmonella genus feature because one strain as resistant as wild type E.coli was found. This resistant strain showed normal excision repair in alkaline sucrose gradient centrifugation experiments. The possible influence of plasmids and mutations in repair genes on the ability of Salmonella to repair UV-damaged DNA is discussed. (orig.) [de

  16. UV-sensitivity and repair of UV-damage in Salmonella of wild type

    Energy Technology Data Exchange (ETDEWEB)

    Kondratiev, Y S; Brukhansky, G V; Andreeva, I V; Skavronskaya, A G [Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Ehpidemiologii i Mikrobiologii

    1977-12-01

    The UV-sensitivity of wild type Salmonella strains has been compared to that of wild type E.coli and its UV-sensitive mutants. Many wild type Salmonella strains are 4-5 times more sensitive than wild type E.coli and their inactivation curve is similar to that for E.coli with a mutation in the polA gene. Alkaline sucrose gradient centrifugation has shown a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a Salmonella genus feature because one strain as resistant as wild type E.coli was found. This resistant strain showed normal excision repair in alkaline sucrose gradient centrifugation experiments. The possible influence of plasmids and mutations in repair genes on the ability of Salmonella to repair UV-damaged DNA is discussed.

  17. Comets in UV

    Science.gov (United States)

    Shustov, B.; Sachkov, M.; Gómez de Castro, A. I.; Vallejo, J. C.; Kanev, E.; Dorofeeva, V.

    2018-04-01

    Comets are important "eyewitnesses" of Solar System formation and evolution. Important tests to determine the chemical composition and to study the physical processes in cometary nuclei and coma need data in the UV range of the electromagnetic spectrum. Comprehensive and complete studies require additional ground-based observations and in situ experiments. We briefly review observations of comets in the ultraviolet (UV) and discuss the prospects of UV observations of comets and exocomets with space-borne instruments. A special reference is made to the World Space Observatory-Ultraviolet (WSO-UV) project.

  18. UV-induced developmental abnormalities in the filamentous blue-green alga Nostoc linckia

    International Nuclear Information System (INIS)

    Tiwari, D.N.

    1978-01-01

    Germinating spores of Nostoc linckia showed higher resistance against UV-irradiation compared to resting spores, maximal resistance being attained more rapidly in the presence of ammonium nitrogen. UV-irradiated germinating spores on further growth formed colonies consisting of abnormally large and spheroidal cells under non-photoreactivating conditions. The formation and fate of these abnormal cells was followed in detail in a mutant clone (M-5) raised from such a colony. Many of these cells formed spores which on return to growth-conducdive conditions germinated giving rise to different types of germlings from the abnormals which in certain cases proved lethal. The possibility of a transient polyenergidic and/or heterozygous state of these 'giant' cells has been discussed. (author)

  19. UV exposure in cars.

    Science.gov (United States)

    Moehrle, Matthias; Soballa, Martin; Korn, Manfred

    2003-08-01

    There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of 'adult' and 'child' dummies. UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3-4% of ambient radiation when the car windows were shut, and 25-31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.

  20. Row orientation effect on UV-B, UV-A and PAR solar irradiation components in vineyards at Tuscany, Italy

    Science.gov (United States)

    Grifoni, D.; Carreras, G.; Zipoli, G.; Sabatini, F.; Dalla Marta, A.; Orlandini, S.

    2008-11-01

    Besides playing an essential role in plant photosynthesis, solar radiation is also involved in many other important biological processes. In particular, it has been demonstrated that ultraviolet (UV) solar radiation plays a relevant role in grapevines ( Vitis vinifera) in the production of certain important chemical compounds directly responsible for yield and wine quality. Moreover, the exposure to UV-B radiation (280-320 nm) can affect plant-disease interaction by influencing the behaviour of both pathogen and host. The main objective of this research was to characterise the solar radiative regime of a vineyard, in terms of photosynthetically active radiation (PAR) and UV components. In this analysis, solar spectral UV irradiance components, broadband UV (280-400 nm), spectral UV-B and UV-A (320-400 nm), the biological effective UVBE, as well as the PAR (400-700 nm) component, were all considered. The diurnal patterns of these quantities and the UV-B/PAR and UV-B/UV-A ratios were analysed to investigate the effect of row orientation of the vineyard in combination with solar azimuth and elevation angles. The distribution of PAR and UV irradiance at various heights of the vertical sides of the rows was also studied. The results showed that the highest portion of plants received higher levels of daily radiation, especially the UV-B component. Row orientation of the vines had a pronounced effect on the global PAR received by the two sides of the rows and, to a lesser extent, UV-A and UV-B. When only the diffused component was considered, this geometrical effect was greatly attenuated. UV-B/PAR and UV-A/PAR ratios were also affected, with potential consequences on physiological processes. Because of the high diffusive capacity of the UV-B radiation, the UV-B/PAR ratio was significantly lower on the plant portions exposed to full sunlight than on those in the shade.

  1. Effect of UV irradiation on cutaneous cicatrices

    DEFF Research Database (Denmark)

    Due, Eva; Rossen, Kristian; Sorensen, Lars Tue

    2007-01-01

    The aim of this study was to examine the effect of ultraviolet (UV) irradiation on human cutaneous cicatrices. In this randomized, controlled study, dermal punch biopsy wounds served as a wound healing model. Wounds healed by primary or second intention and were randomized to postoperative solar UV...... postoperatively, UV-irradiated cicatrices healing by second intention: (i) were significantly pointed out as the most disfiguring; (ii) obtained significantly higher scores of colour, infiltration and cicatrix area; and (iii) showed significantly higher increase in skin-reflectance measurements of skin......-pigmentation vs. non-irradiated cicatrices. No histological, immunohistochemical or biochemical differences were found. In conclusion, postoperative UV exposure aggravates the clinical appearance of cicatrices in humans....

  2. UV-induced effects

    NARCIS (Netherlands)

    Liebsch, M.; Spielmann, H.; Pape, W.; Krul, C.; Deguercy, A.; Eskes, C.A.M.

    2005-01-01

    Regulatory requirements: According to the current Notes for Guidance of the Scientific Committee on Cosmetic Products and Non-Food Products (SCCNFP), cosmetic ingredients and mixtures of ingredients absorbing UV light (in particular UV filter chemicals used, for example, to ensure the light

  3. Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device.

    Science.gov (United States)

    Boyce, John M; Farrel, Patricia A; Towle, Dana; Fekieta, Renee; Aniskiewicz, Michael

    2016-06-01

    OBJECTIVE To evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device. DESIGN Prospective observational study. METHODS We used 6 UV light sensors to determine UV-C irradiance (W/cm2) and UV-C dosage (µWsec/cm2) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA. RESULTS Mean UV-C irradiance was nearly 1.0E-03 W/cm2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P4 to 1-3 for MRSA, >4 to 1-2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles. CONCLUSION UV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device. Infect Control Hosp Epidemiol 2016;37:667-672.

  4. Effect of a new fluorochrome on pre- and post-UV treatment of Taphrina maculans Butler

    International Nuclear Information System (INIS)

    Singh, U.P.; Nagai, S.

    1977-01-01

    Taphrina maculans Butler incites leaf spots disease in turmeric (Curcuma longa L.) plants. The patogen forms two types of colonies namely, salmon-red and creamy-white in the artifical medium when isolated from a single infection spot. Both strains resemble yeasts in morphology. The two strains were subjected to UV irradiation. The salmon-red one showed higher resistance to UV than the white one, presumably due to the presence of a red pigment in the former. When spores of the salmon-red strain were pre-treated with a new fluorochrome Hoechst 33258 the survival decreased. Decreased survival of the salmon-red strain was also oberved during post-treatment which is probably due to the combined effect of UV and dye. The creamy-white strain differs from the salmon-red one in UV sensitivity, and also during combined treatment with UV and dye. During pre-treatment the organism shows more survival than during post-treatment with the fluorochrome. This differential response is discussed in the light of repair mechanisms involved in the organism. (author)

  5. Assays of residual antibiotics after treatment of γ-ray and UV irradiation

    International Nuclear Information System (INIS)

    Shin, Ji Hye; Nam, Ji Hyun; Lee, Dong Hun; Yu, Seung Ho; Lee, Myun Joo

    2010-01-01

    The pollution of antibiotics is a major cause of spreading antibiotics resistant bacteria in the environment. Applications of ozonation, UV, and γ-ray irradiations have been introduced to remove antibiotics in the effluents from wastewater treatment system. In this study, we compared the chemical (HPLC) and biological (antimicrobial susceptibility test, AMS) assays in measuring of the concentrations of residual antibiotics after γ-ray and UV irradiation. Most samples were degraded by γ-ray irradiation (1 ∼ 2 kGy). However, lincomycin and tetracycline were not degraded by UV irradiation. The concentration of residual antibiotics, that was treated with γ-ray and UV irradiation, measuring by bioassay was similar to HPLC. The concentrations of γ-ray irradiated cephradine measured by AMS test were 2 times higher than of HPLC assay, indicating AMS test is more sensitive than HPLC assay. These results indicate that γ-ray irradiation technique is more useful than UV irradiation, and biological assay is more useful to detect the antibiotics and toxic intermediates in antibiotics degradation

  6. 207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

    Full Text Available BACKGROUND: 0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ~200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure. AIMS: The aim of this work was to test the biophysically-based hypothesis that ~200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues. METHODS: A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts were measured, for both UV radiations incident on 3-D human skin tissue. RESULTS: We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp. CONCLUSIONS: As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively

  7. 207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies.

    Science.gov (United States)

    Buonanno, Manuela; Randers-Pehrson, Gerhard; Bigelow, Alan W; Trivedi, Sheetal; Lowy, Franklin D; Spotnitz, Henry M; Hammer, Scott M; Brenner, David J

    2013-01-01

    0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ~200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure. The aim of this work was to test the biophysically-based hypothesis that ~200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues. A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA) bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) were measured, for both UV radiations incident on 3-D human skin tissue. We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp. As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively reducing surgical-site infection rates, including those of drug-resistant

  8. Mechanisms of uv mutagenesis in yeast

    International Nuclear Information System (INIS)

    Lawrence, C.W.; Christensen, R.; Schwartz, A.

    1982-01-01

    The uv mutagenesis in yeast depends on the function of the RAD6 locus, a gene that is also responsible for a substantial fraction of wild-type resistance, suggesting that this eukaryote may possess a misrepair mechanism analogous to that proposed for Escherichia coli. The molecular mechanism responsible for RAD6 repair or recovery is not yet known, but it is different from either excision or recombination-dependent repair, processes carried out by the other two main repair pathways in yeast. RAD6-dependent mutagenesis has been found to have the following characteristics. It is associated at best with only a small fraction of RAD6-dependent repair, the majority of the sensitivity of rad6 mutants being due to their lack of nonmutagenic repair. SRS2 metabolic suppressors restore a substantial fraction of uv resistance to rad6 mutants but do not restore their uv mutability. Strains containing mutations at loci (rev, umr) that are probably more directly involved in mutagenesis are only mildly sensitive, and there is a poor correlation between their sensitivity and mutational deficiency. The uv mutagenesis appears to require a large number of gene functions, perhaps ten or more. Where examined in detail, these genes have been found to be concerned in the production of only a specific range of mutational events, not all of them. Mating experiments have shown that a substantial fraction, probably 40% or more, of uv-induced mutations are untargeted, that is, occur in lesion-free regions of DNA. The uv irradiation, therefore, produces a general reduction in the normally high fidelity with which DNA is replicated on undamaged templates. It does not appear to be necessary for the causal lesion to be present in the same chromosome as the mutation it induces. The reduction in fidelity may be the consequence of the production of a diffusible factor in uv-irradiated cells, but definite evidence supporting this proposal has not yet been obtained

  9. Potential application of UV radiation processing in electronic packaging

    International Nuclear Information System (INIS)

    Ng Chee Mang; Lim Yoke Keem; Kumar, R.N.

    1999-01-01

    UV-curable epoxies have been formulated for use in place of the established heat cure epoxy systems for coating, adhesion and encapsulation of electronic devices. The UV-cured epoxy systems can be formulated to give comparable or even better physical and chemical properties than the more common heat cured systems. The UV systems offer significant advantage in very fast cure and hence very short production cycle time. UV systems can also be formulated to give desired properties of increased strength, high Tg, increased humidity resistance and improved temperature cycling performance

  10. UV stabilization of wood by nano metal oxides dispersed in propylene glycol.

    Science.gov (United States)

    Nair, Sreeja; Nagarajappa, Giridhar B; Pandey, Krishna K

    2018-06-01

    Nanoparticles of some of the metal oxides are known to have high UV protective efficiency. The UV filtering efficiency of nanoparticles invariably depends on their size and stability in the dispersion. In the present work, a stable dispersion of nanoparticles of three metal oxides, zinc oxide (ZnO), cerium oxide (CeO 2 ) and titanium dioxide (TiO 2 ), was prepared in propylene glycol (PG) using ultrasonication. The method is easy and useful as no additional surfactant or dispersant is needed. The particle size and its distribution was confirmed by Scanning Electron Microscopy and Dynamic Light Scattering. The stability of dispersion was assessed by UV-visible absorption spectroscopy. The UV stability of wood surfaces of Wrightia tinctoria coated with nanodispersions of ZnO, CeO 2 and TiO 2 was evaluated under laboratory conditions in an accelerated weathering tester. Changes in the colour and FTIR spectra of exposed specimens were measured periodically. Rapid colour darkening (yellowing) was observed in uncoated and PG coated specimens. In contrast, nanodispersion coated specimens prevented photo-yellowing considerably with significant reduction in colour changes examined by CIE L*, a*, b* and ΔE*. Increase in concentration of nanoparticles in the dispersion imparted higher resistance to UV induced degradation. However, increased concentration of nanoparticles reduced the transparency of the coating. FTIR analysis indicated rapid degradation of lignin in uncoated and PG coated specimens due to UV exposure. Coating of wood surfaces with nanodispersions restricted lignin degradation. The study also demonstrates the potential of propylene glycol as a dispersant for developing stable and efficient UV protective nanodispersions for wood coating. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  12. UV ability to destroy poliovirus end FRNA specific bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J.; Joret, J.C.; Lesavre, J.; Perrot, J.Y.

    1996-01-01

    In France, the use of ultraviolet radiation to disinfect secondary effluents is only in its initial stage. The aim of this study was to examine the ability of UV to destroy Poliovirus Type 1 and FRNA specific bacteriophages (laboratory MS2 phages and indigenous phages). Concentrated viral solutions were mixed with secondary effluents artificially enriched with suspended solids and then irradiated at various UV dose in a collimated beam. Bacteriological analysis of Escherichia coli and enterococci were performed at the same time. UV were very efficient to kill Poliovirus : Inactivation of 3 and 5 log units were observed respectively at UV doses of 20 and 40 mW/cm{sup 2}. The Poliovirus disinfection rate was almost the same than Escherichia coli. Enterococci were more resistant than E. coli. Inactivation of MS2 bacteriophages was significantly correlated to UV dose following the relationship MS2 Inactivation = 0.047{sup *} Dose + 0,396. At UV dose of 20 mWs/cm{sup 2}, MS2 phages were 2.3 times more resistant to UV than Poliovirus, i.e. they need UV dose 2,3 times greater to be disinfected at the same level. A review of the literature has also shown that viruses more resistant to UV treatment have never been reported. All this would tend to confirm the interest of this group of virus as indicators of the disinfection efficiency of UV, which could indicate, on site, the inactivation of pathogenic viruses. Inactivation rates obtained for FRNA phages proved the good virucidal activity of UV. The inactivation of indigenous FRNA bacteriophages was not correlated with E. coli inactivation. On the other hand, it was correlated with enterococci inactivation. (Author). 23 refs., 7 figs., 4 tabs.

  13. Use of satellite erythemal UV products in analysing the global UV changes

    Directory of Open Access Journals (Sweden)

    I. Ialongo

    2011-09-01

    Full Text Available Long term changes in solar UV radiation affect global bio-geochemistry and climate. The satellite-based dataset of TOMS (Total Ozone Monitoring System and OMI (Ozone Monitoring Instrument of erythemal UV product was applied for the first time to estimate the long-term ultraviolet (UV changes at the global scale. The analysis of the uncertainty related to the different input information is presented. OMI and GOME-2 (Global Ozone Monitoring Experiment-2 products were compared in order to analyse the differences in the global UV distribution and their effect on the linear trend estimation.

    The results showed that the differences in the inputs (mainly surface albedo and aerosol information used in the retrieval, affect significantly the UV change calculation, pointing out the importance of using a consistent dataset when calculating long term UV changes. The areas where these differences played a major role were identified using global maps of monthly UV changes. Despite the uncertainties, significant positive UV changes (ranging from 0 to about 5 %/decade were observed, with higher values in the Southern Hemisphere at mid-latitudes during spring-summer, where the largest ozone decrease was observed.

  14. Lower Circulating B12 Is Associated with Higher Obesity and Insulin Resistance during Pregnancy in a Non-Diabetic White British Population.

    Directory of Open Access Journals (Sweden)

    Bridget Ann Knight

    Full Text Available Vitamin B12 and folate are critical micronutrients needed to support the increased metabolic demands of pregnancy. Recent studies from India have suggested that low vitamin B12 and folate concentrations in pregnancy are associated with increased obesity; however differences in diet, antenatal vitamin supplementation, and socioeconomic status may limit the generalisability of these findings. We aimed to explore the cross-sectional relationship of circulating serum vitamin B12 and folate at 28 weeks' gestation with maternal adiposity and related biochemical markers in a white non diabetic UK obstetric cohort.Anthropometry and biochemistry data was available on 995 women recruited at 28 weeks gestation to the Exeter Family Study of Childhood Health. Associations between B12 and folate with maternal BMI and other obesity-related biochemical factors (HOMA-R, fasting glucose, triglycerides, HDL and AST were explored using regression analysis, adjusting for potential confounders (socioeconomic status, vegetarian diet, vitamin supplementation, parity, haemodilution (haematocrit.Higher 28 week BMI was associated with lower circulating vitamin B12 (r = -0.25; P<0.001 and folate (r = -0.15; P<0.001. In multiple regression analysis higher 28 week BMI remained an independent predictor of lower circulating B12 (β (95% CI = -0.59 (-0.74, -0.44 i.e. for every 1% increase in BMI there was a 0.6% decrease in circulating B12. Other markers of adiposity/body fat metabolism (HOMA-R, triglycerides and AST were also independently associated with circulating B12. In a similar multiple regression AST was the only independent obesity-related marker associated with serum folate (β (95% CI = 0.16 (0.21, 0.51.In conclusion, our study has replicated the previous Indian findings of associations between lower serum B12 and higher obesity and insulin resistance during pregnancy in a non-diabetic White British population. These findings may have important implications for

  15. /UV Synergistic Aging of Polyester Polyurethane Film Modified by Composite UV Absorber

    Directory of Open Access Journals (Sweden)

    Yanzhi Wang

    2013-01-01

    Full Text Available The pure polyester polyurethane (TPU film and the modified TPU (M-TPU film containing 2.0 wt.% inorganic UV absorbers mixture (nano-ZnO/CeO2 with weight ratio of 3 : 2 and 0.5 wt.% organic UV absorbers mixture (UV-531/UV-327 with weight ratio of 1 : 1 were prepared by spin-coating technique. The accelerated aging tests of the films exposed to constant UV radiation of 400 ± 20 µW/cm2 (313 nm with an ozone atmosphere of 100 ± 2 ppm were carried out by using a self-designed aging equipment at ambient temperature and relative humidity of 20%. The aging resistance properties of the films were evaluated by UV-Vis spectra, Fourier transform infrared spectra (FT-IR, photooxidation index, and carbonyl index analysis. The results show that the composite UV absorber has better protection for TPU system, which reduces distinctly the degradation of TPU film. O3/UV aging of the films increases with incremental exposure time. PI and CI of TPU and M-TPU films increase with increasing exposure time, respectively. PI and CI of M-TPU films are much lower than that of TPU film after the same time of exposure, respectively. Distinct synergistic aging effect exists between ozone aging and UV aging when PI and CI are used as evaluation index, respectively. Of course, the formula of these additives needs further improvement for industrial application.

  16. UV-irradiation enhances rice allelopathic potential in rhizosphere soil

    DEFF Research Database (Denmark)

    Mahmood, Khalid; Khan, Muhammad Bismillah; Song, Yuan Yuan

    2013-01-01

    Ultraviolet-B radiation is rising continuously due to stratospheric ozone depletion over temperate latitudes. This study investigated effects of UV exposure on rice allelopathic potentials. For this purpose, two rice (Oryza sativa L.) cultivars BR-41 (high allelopathic = able to inhibit neighboring...... grass and lettuce). These bioassays showed significant inhibition in lettuce and barnyard growth after UV in both rice cultivars. Interestingly, Huajingxian, which did not exhibit allelopathic potential in absence of UV showed significant inhibition after UV exposure. Phenolics, enzymes activities...... and genes responsible for biosynthesis of allelopathic compounds were examined after UV exposure. Phenolic compounds accumulated in rice leaves were quantified through HPLC analysis. They were significantly higher in BR-41 leaves after UV exposure. Enzyme activities (PAL and C4H) were significantly higher...

  17. Studies on the resistance/reactivation of Giardia muris cysts and Cryptosporidium parvum oocysts exposed to medium-pressure ultraviolet radiation.

    Science.gov (United States)

    Belosevic, M; Craik, S A; Stafford, J L; Neumann, N F; Kruithof, J; Smith, D W

    2001-10-16

    The ex vivo and in vivo reactivation of Giardia muris cysts and Cryptosporidium parvum oocysts after exposure to different doses of ultraviolet (UV) radiation was determined using animal infectivity. The infectivity of UV-treated parasites stored for 1-4 days (G. muris) or 1-17 days (C. parvum) at room temperature in the dark was similar to that of organisms administered immediately after UV treatment, indicating that the parasites did not reactivate ex vivo. In contrast, we observed in vivo reactivation of G. muris in three of seven independent animal infectivity experiments, when parasites were treated with relatively low doses of medium-pressure UV (muris cysts and C. parvum oocysts exposed to medium-pressure UV doses of 60 mJ/cm(2) or higher did not exhibit resistance to and/or reactivation following treatment. This suggests that when appropriate doses of UV are used, significant and permanent inactivation of these parasites may be achieved.

  18. The Aspergillus uvsH gene encodes a product homologous to yeast RAD18 and Neurospora UVS-2.

    Science.gov (United States)

    Yoon, J H; Lee, B J; Kang, H S

    1995-07-28

    The uvsH DNA repair gene of Aspergillus nidulans has been cloned by complementation of the uvsH77 mutation with a cosmid library containing genomic DNA inserts from a wild-type strain. Methylmethane sulfonate (MMS)-resistant transformants were obtained on medium containing 0.01% MMS, to which uvsH mutants exhibit high sensitivity. Retransformation of uvsH77 mutants with the rescued cosmids from the MMS-resistant transformants resulted in restoration of both UV and MMS resistance to wild-type levels. Nucleotide sequence analysis of the genomic DNA and cDNA of the uvsH gene shows that it has an open reading frame (ORF) of 1329 bp, interrupted by two introns of 51 and 61 bp. A 2.4 kb transcript of the uvsH gene was detected by Northern blot analysis. Primer extension analysis revealed that transcription starts at 31 bp upstream from the translation initiation codon. This gene encodes a predicted polypeptide of 443 amino acids, which has two unique zinc finger motifs. The proposed polypeptide displays 39% identity to the Neurospora crassa UVS-2 protein and 24% identity to the Saccharomyces cerevisiae RAD18 protein. The sequence similarity is particularly high in three domains. One zinc finger (RING finger) motif is located in the first domain close to the N-terminus. The other zinc finger motif is in the second domain. In the third domain, the mutation sites in both the uvsH77 and uvsH304 alleles were identified.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. UV-induced structural changes in chromatin

    International Nuclear Information System (INIS)

    Lang, H.; Zimmer, C.; Vengerov, Yu.Yu.

    1985-01-01

    UV-induced structural alterations of chromatin were studied by means of CD, electron microscopic, and gel electrophoretic measurements. The results indicate that chromatin undergoes serious structural changes after irradiation even at very low fluences. In the low fluence range the structural transitions from the higher ordered chromatin structure to the unfolded state occur without detectable changes in the content of histone H1 and of the core histones. Histone H1 disappears only at fluences above 10 kJ/m 2 . Furthermore, DNA in chromatin is much more sensitive against UV-irradiation and shows a higher degree of strand scission relative to free DNA. While fragmentation in free DNA occurs at fluences above 15 kJ/m 2 , it occurs even at 5.5 kJ/m 2 in the case of chromatin. The biological meaning of the observed UV-induced structural alterations of chromatin is discussed. (author)

  20. An Evaluation of UV-Monitoring Enhanced Skin Cancer Prevention among Farm Youth in Rural Virginia

    Science.gov (United States)

    Chen, Yi-Chun; Ohanehi, Donatus C.; Redican, Kerry J.

    2015-01-01

    Background: Health districts in southwest Virginia have one of the highest ultraviolet (UV) radiation exposure and sunburn rate. Due to higher levels of UV exposure, rural farm youth are at higher risk for skin cancer than non-farm youth. Few studies have been published that explore best practices for decreasing UV exposure among this population.…

  1. Kinetic removal of haloacetonitrile precursors by photo-based advanced oxidation processes (UV/H2O2, UV/O3, and UV/H2O2/O3).

    Science.gov (United States)

    Srithep, Sirinthip; Phattarapattamawong, Songkeart

    2017-06-01

    The objective of the study is to evaluate the performance of conventional treatment process (i.e., coagulation, flocculation, sedimentation and sand filtration) on the removals of haloacetonitrile (HAN) precursors. In addition, the removals of HAN precursors by photo-based advanced oxidation processes (Photo-AOPs) (i.e., UV/H 2 O 2 , UV/O 3 , and UV/H 2 O 2 /O 3 ) are investigated. The conventional treatment process was ineffective to remove HAN precursors. Among Photo-AOPs, the UV/H 2 O 2 /O 3 was the most effective process for removing HAN precursors, followed by UV/H 2 O 2 , and UV/O 3 , respectively. For 20min contact time, the UV/H 2 O 2 /O 3 , UV/H 2 O 2 , and UV/O 3 suppressed the HAN formations by 54, 42, and 27% reduction. Increasing ozone doses from 1 to 5 mgL -1 in UV/O 3 systems slightly improved the removals of HAN precursors. Changes in pH (6-8) were unaffected most of processes (i.e., UV, UV/H 2 O 2 , and UV/H 2 O 2 /O 3 ), except for the UV/O 3 system that its efficiency was low in the weak acid condition. The pseudo first-order kinetic constant for removals of dichloroacetonitrile precursors (k' DCANFP ) by the UV/H 2 O 2 /O 3 , UV/H 2 O 2 and standalone UV systems were 1.4-2.8 orders magnitude higher than the UV/O 3 process. The kinetic degradation of dissolved organic nitrogen (DON) tended to be higher than the k' DCANFP value. This study firstly differentiates the kinetic degradation between DON and HAN precursors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Disinfection efficiency of peracetic acid, UV and ozone after enhanced primary treatment of municipal wastewater.

    Science.gov (United States)

    Gehr, Ronald; Wagner, Monika; Veerasubramanian, Priya; Payment, Pierre

    2003-11-01

    The City of Montreal Wastewater Treatment Plant uses enhanced physicochemical processes (ferric and/or alum coagulation) for suspended solids and phosphorus removal. The objective of this study was to assess the ability of peracetic acid (PAA), UV, or ozone to inactivate the indicator organisms fecal coliforms, Enterococci, MS-2 coliphage, or Clostridium perfringens in the effluent from this plant. PAA doses to reach the target fecal coliform level of 9000 CFU/100mL exceeded 6 mg/L; similar results were obtained for enterococci, and no inactivation of Clostridium perfringens was observed. However a 1-log reduction of MS-2 occurred at PAA doses of 1.5 mg/L and higher. It was expected that this effluent would have a high ozone demand, and would require relatively high UV fluences, because of relatively high effluent COD, iron and suspended solids concentrations, and low UV transmittance. This was confirmed herein. For UV, the inactivation curve for fecal coliforms showed the typical two-stage shape, with the target of 1000 CFU/100 mL (to account for photoreactivation) occurring in the asymptote zone at fluences >20 mJ/cm(2). In contrast, inactivation curves for MS-2 and Clostridium perfringens were linear. Clostridium perfringens was the most resistant organism. For ozone, inactivation was already observed before any residuals could be measured. The transferred ozone doses to reach target fecal coliform levels ( approximately 2-log reduction) were 30-50 mg/L. MS-2 was less resistant, but Clostridium perfringens was more resistant than fecal coliforms. The different behaviour of the four indicator organisms studied, depending on the disinfectant, suggests that a single indicator organism might not be appropriate. The required dose of any of the disinfectants is unlikely to be economically viable, and upstream changes to the plant will be needed.

  3. Characterization of DNA-repair potential in deep subsurface bacteria challenged by UV light, hydrogen peroxide, and gamma radiation

    OpenAIRE

    Arrage, Andrew Anthony

    1991-01-01

    Subsurface bacterial isolates obtained through the DOE Subsurface Science Program were tested for resistance to UV light, gamma radiation and H202. Some deep subsurface bacteria were resistant to UV light, demonstrating â ¥1.0% survival at fluences which resulted in a 0.0001% survival level of E. coli B. The percentage of UV resistant aerobic subsurface bacteria and surface soil bacteria were similar; 30.8% and 25.8% respectively. All of the microaerophilic subsurface isolates ...

  4. UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

    Directory of Open Access Journals (Sweden)

    Ricarda Modarressie

    2015-05-01

    Full Text Available Social aggregations occur in many different animal taxa and mainly result from non-random assortment. Investigating factors that shape and maintain the composition of social aggregations are among others a main topic for understanding ecological speciation processes. Aggregation decisions are mediated by olfactory and visual cues, which in many animals are extended into the UV part of the electromagnetic spectrum. Here, we were interested in developmental plasticity of social preferences with respect to UV radiation in aquatic organisms. Specifically, we tested whether different lighting environments with respect to UV wavelengths during early life stages influence the shoaling preference in juvenile threespine sticklebacks (Gasterosteus aculeatus. Family (full-sibling groups were split and reared under UV-lacking (UV- and UV-present (UV+ lighting conditions. Subsequent shoal choice experiments, in which test fish from both rearing conditions could simultaneously choose between a shoal seen behind a UV-blocking (UV- and a shoal seen behind a UV-transmitting (UV+ filter, revealed a significant effect of lighting condition during rearing on association preference. Test fish that had been deprived of UV spent significantly more time near the UV- shoal compared to the test fish reared under full-spectrum lighting conditions. The results are discussed with respect to plasticity of the visual system and environmental lighting conditions.

  5. Reverse-contact UV nanoimprint lithography for multilayered structure fabrication

    DEFF Research Database (Denmark)

    Kehagias, N.; Reboud, V.; Chansin, G.

    2007-01-01

    In this paper, we report results on a newly developed nanofabrication technique, namely reverse-contact UV nanoimprint lithography. This technique is a combination of nanoimprint lithography and contact printing lithography. In this process, a lift-off resist and a UV cross-linkable polymer...... are spin-coated successively onto a patterned UV mask-mould. These thin polymer films are then transferred from the mould to the substrate by contact at a suitable temperature and pressure. The whole assembly is then exposed to UV light. After separation of the mould and the substrate, the unexposed...... polymer areas are dissolved in a developer solution leaving behind the negative features of the original stamp. This method delivers resist pattern transfer without a residual layer, thereby rending unnecessary the etching steps typically needed in the imprint lithography techniques for three...

  6. Reverse-contact UV nanoimprint lithography for multilayered structure fabrication

    International Nuclear Information System (INIS)

    Kehagias, N; Reboud, V; Chansin, G; Zelsmann, M; Jeppesen, C; Schuster, C; Kubenz, M; Reuther, F; Gruetzner, G; Torres, C M Sotomayor

    2007-01-01

    In this paper, we report results on a newly developed nanofabrication technique, namely reverse-contact UV nanoimprint lithography. This technique is a combination of nanoimprint lithography and contact printing lithography. In this process, a lift-off resist and a UV cross-linkable polymer are spin-coated successively onto a patterned UV mask-mould. These thin polymer films are then transferred from the mould to the substrate by contact at a suitable temperature and pressure. The whole assembly is then exposed to UV light. After separation of the mould and the substrate, the unexposed polymer areas are dissolved in a developer solution leaving behind the negative features of the original stamp. This method delivers resist pattern transfer without a residual layer, thereby rending unnecessary the etching steps typically needed in the imprint lithography techniques for three-dimensional patterning. Three-dimensional woodpile-like structures were successfully fabricated with this new technique

  7. UV-inducible DNA repair in the cyanobacteria Anabaena spp

    International Nuclear Information System (INIS)

    Levine, E.; Thiel, T.

    1987-01-01

    Strains of the filamentous cyanobacteria Anabaena spp. were capable of very efficient photoreactivation of UV irradiation-induced damage to DNA. Cells were resistant to several hundred joules of UV irradiation per square meter under conditions that allowed photoreactivation, and they also photoreactivated UV-damaged cyanophage efficiently. Reactivation of UV-irradiated cyanophage (Weigle reactivation) also occurred; UV irradiation of host cells greatly enhanced the plaque-forming ability of irradiated phage under nonphotoreactivating conditions. Postirradiation incubation of the host cells under conditions that allowed photoreactivation abolished the ability of the cells to perform Weigle reactivation of cyanophage N-1. Mitomycin C also induced Weigle reactivation of cyanophage N-1, but nalidixic acid did not. The inducible repair system (defined as the ability to perform Weigle reactivation of cyanophages) was relatively slow and inefficient compared with photoreactivation

  8. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

    The use of synchrotron radiation (SR) in the ultraviolet (UV) region by biophysics and biophysical chemists continues to increase as access improves and as awareness of its unique combination of properties grows. SR is continuously tunable, intense (even in the UV region), and pulsed. Pulse characteristics are comparable to those of picosecond lasers, but have the advantage of being independent of wavelength. Drawbacks are the continuous, but slow, decay of intensity arising from loss of particles in the ring, and the intrinsic limitation in pulse repetition rate. The particular combination of features that makes SR a superior light source depends upon the application. Spectroscopic techniques based on absorption and some techniques based on emission exploit its intensity and continuous tunability; time resolved techniques make use of its pulse characteristics. This chapter is a status report on two of the major biological applications of UV SR, circular dichroism and time-resolved fluorescence, covering mainly the published literature of the last five years. For the present purpose, the term UV is understood to include the vacuum ultraviolet region to 100 nm. (author). 83 refs.; 4 figs.; 6 tabs

  9. Complementation of the UV-sensitive phenotype of a xeroderma pigmentosum human cell line by transfection with a cDNA clone library

    International Nuclear Information System (INIS)

    Teitz, T.; Naiman, T.; Avissar, S.S.; Bar, S.; Okayama, H.; Canaani, D.

    1987-01-01

    In previous work, a xeroderma pigmentosum cell line belonging to complementation group C was established by transformation with origin-defective simian virus 40. We now report the complementation of the UV sensitivity of this cell line by gene transfer. A human cDNA clone library constructed in a mammalian expression vector, and itself incorporated in a lambda phage vector, was introduced into the cells as a calcium phosphate precipitate. Following selection to G418 resistance, provided by the neo gene of the vector, transformants were selected for UV resistance. Twenty-one cell clones were obtained with UV-resistance levels typical of normal human fibroblasts. All transformants contained vector DNA sequences in their nuclei. Upon further propagation in the absence of selection for G418 resistance, about half of the primary transformants remained UV-resistant. Secondary transformants were generated by transfection with a partial digest of total chromosomal DNA from one of these stable transformants. This resulted in 15 G418-resistant clones, 2 of which exhibited a UV-resistant phenotype. The other primary clones lost UV resistance rapidly when subcultured in the absence of G418. Importantly, several retained UV resistance under G418 selection pressure. The acquisition of UV resistance by secondary transformants derived by transfection of DNA from a stable primary transformant, and the linkage between G418 and UV resistances in the unstable primary transformants, strongly suggests that the transformants acquired UV resistance through DNA-mediated gene transfer and not by reversion

  10. Chinese hamster ovary mutant UV-1 is hypomutable and defective in a postreplication recovery process

    International Nuclear Information System (INIS)

    Stamato, T.D.; Hinkle, L.; Collins, A.R.; Waldren, C.A.

    1981-01-01

    CHO-UV-1 is a mutant of the Chinese hamster cell CHO-K1 hypersensitive to killing by ultraviolet light but with normal resistance to X-ray. It is also hypersensitive to killing by ethyl methane sulfonate. Hybrid clones formed bu fusing UV-1 and Chinese hamster lung cells display the normal ultraviolet resistance of the latter. The sensitive phenotype behaves, therefore, in a genetically recessive manner. Ultraviolet sensitivity of UV-1 is not associated with a deficiency in excision repair. Alkaline sucrose gradient sedimentation analysis of nascent DNA from ultraviolet-irradiated cells reveals that UV-1 is, however, markedly deficient in postreplication recovery. Furthermore, UV-1 has a lower rate of induced mutation to 6-thioguanine resistance than does the parental cell when treated with ultraviolet light or ethyl methane sulfonate. These results suggest that the phenotype of UV-1 is due to a mutation in a form of postreplication recovery which in normal cells is error prone

  11. Optical and UV-Aging Properties of LDH-Modified Bitumen

    Directory of Open Access Journals (Sweden)

    Xing Liu

    2015-07-01

    Full Text Available Layered double hydroxides (LDHs are an ultraviolet-light (UV resistant material. In this study, LDHs were used to modify bitumen. The optical and UV aging properties of LDHs modified bitumen were investigated. Firstly, the thin films of bitumen, with and without LDHs, were prepared. By using the UV-Vis spectrophotometer, absorbance, reflectance, and transmittance of bituminous thin film were evaluated. The morphology of LDHs-modified bitumen was observed by using fluorescence microscopy (FM. Finally, the aging resistance of LDH-modified bitumen was investigated by using the UV-aging oven. Results indicated that the LDHs, especially with 5 wt % in the bitumen, can effectively absorb and reflect the UV light and improve the UV-aging resistance of bitumen. This implied that the addition of LDHs into bitumen had the potential to prolong the service life of asphalt pavement.

  12. Influence of interconnection on the long-term reliability of UV LED packages

    Science.gov (United States)

    Nieland, S.; Mitrenga, D.; Karolewski, D.; Brodersen, O.; Ortlepp, T.

    2017-02-01

    High power LEDs have conquered the mass market in recent years. Besides the main development focus to achieve higher productivity in the field of visible semiconductor LED processing, the wavelength range is further enhanced by active research and development in the direction of UVA / UVB / UVC. UVB and UVC LEDs are new and promising due to their numerous advantages. UV LEDs emit in a near range of one single emission peak with a width (FWHM) below 15 nm compared to conventional mercury discharge lamps and xenon sources, which show broad spectrums with many emission peaks over a wide range of wavelengths. Furthermore, the UV LED size is in the range of a few hundred microns and offers a high potential of significant system miniaturization. Of course, LED efficiency, lifetime and output power have to be increased [1]. Lifetime limiting issues of UVB/UVC-LED are the very high thermal stress in the chip resulting from the higher forward voltages (6-10 V @ 350 mA), the lower external quantum efficiency, below 10 % (most of the power disappears as heat), and the thermal resistance Rth of conventional LED packages being not able to dissipate these large amounts of heat for spreading. Beside the circuit boards and submounts which should have maximum thermal conductivity, the dimension of contacts as well as the interconnection of UV LED to the submount/package determinates the resolvable amount of heat [2]. In the paper different innovative interconnection techniques for UVC-LED systems will be discussed focused on the optimization of thermal conductivity in consideration of the assembly costs. Results on thermal simulation for the optimal contact dimensions and interconnections will be given. In addition, these theoretical results will be compared with results on electrical characterization as well as IR investigations on real UV LED packages in order to give recommendations for optimal UV LED assembly.

  13. Efficacy of UV-irradiated larval vaccine of Ancylostoma ceylanicum (Looss, 1911) in golden hamsters (Merocricetus auratus)

    International Nuclear Information System (INIS)

    Menon, S.; Bhopale, M.K.

    1985-01-01

    A vaccination trial in golden hamsters with UV-irradiated infective larvae of Ancylostoma ceylanicum was attempted. One oral vaccination of hamsters with 100 infective larvae irradiated by means of UV-tube (390 nm) at different time intervals induced the development of resistance. As the time exposure of irradiation was increased, there was a corresponding decrease in the subsequent worm establishment. A high level of protection afforded by larvae irradiated for 15 min UV-exposure was recorded giving 99.0% and 95.0% worm reduction against the challenge doses of 100 and 1000 normal larvae respectively. There was no marked difference in worm establishment in hamsters vaccinated either orally or subcutaneously, followed by oral challenge. In the vaccinated hamsters, the manifestations of resistance at 15 min UV-exposure were shown by marked reduction in worm establishment and highly reduced epg in pellets with significantly higher blood haemoglobin levels compared with those given normal larvae as vaccine and challenge controls. (author)

  14. UV radiation dependent flavonoid accumulation of Cistus laurifolius L

    International Nuclear Information System (INIS)

    Vogt, T.; Gülz, P.-G.; Reznik, H.

    1991-01-01

    Epicuticular and intracellular flavonoids of Cistus laurifolius grown with and without UV radiation in a phytotron as well as under natural garden conditions in the field were studied. The amount of intracellular flavonoid glycosides of leaves receiving UV-A radiation was two fold higher than that measured in the absence o f UV-A radiation, whether grown in the phytotron or in the field. Exposure of previously protected leaves to UV-A radiation increased the intracellular flavonoid glycoside content to that of unprotected leaves. The qualitative composition of intracellular flavonoid glycosides showed a reduced amount of quercetin-3-galactoside to the myricetin monosides when the leaves were grown without UV-A radiation in the field and in the phytotron. Epicuticular flavonoid aglycones were not influenced by UV radiation significantly. (author)

  15. Photodegradation of sulfasalazine and its human metabolites in water by UV and UV/peroxydisulfate processes.

    Science.gov (United States)

    Ji, Yuefei; Yang, Yan; Zhou, Lei; Wang, Lu; Lu, Junhe; Ferronato, Corinne; Chovelon, Jean-Marc

    2018-04-15

    The widespread occurrence of pharmaceuticals and their metabolites in natural waters has raised great concerns about their potential risks on human health and ecological systems. This study systematically investigates the degradation of sulfasalazine (SSZ) and its two human metabolites, sulfapyridine (SPD) and 5-aminosalicylic acid (5-ASA), by UV and UV/peroxydisulfate (UV/PDS) processes. Experimental results show that SPD and 5-ASA were readily degraded upon UV 254 nm direct photolysis, with quantum yields measured to be (8.6 ± 0.8) × 10 -3 and (2.4 ± 0.1) × 10 -2  mol Einstein -1 , respectively. Although SSZ was resistant to direct UV photolysis, it could be effectively removed by both UV/H 2 O 2 and UV/PDS processes, with fluence-based pseudo-first-order rate constants determined to be 0.0030 and 0.0038 cm 2  mJ -1 , respectively. Second-order rate constant between SO 4 •- and SSZ was measured as (1.33 ± 0.01) × 10 9  M -1 s -1 by competition kinetic method. A kinetic model was established for predicting the degradation rate of SSZ in the UV/PDS process. Increasing the dosage of PDS significantly enhanced the degradation of SSZ in the UV/PDS process, which can be well predicted by the developed kinetic model. Natural water constituents, such as natural organic matter (NOM) and bicarbonate (HCO 3 - ), influenced the degradation of SSZ differently. The azo functional group of SSZ molecule was predicted as the reactive site susceptible to electrophilic attack by SO 4 •- by frontier electron densities (FEDs) calculations. Four intermediate products arising from azo bond cleavage and SO 2 extrusion were identified by solid phase extraction-liquid chromatography-triple quadrupole mass spectrometry (SPE-LC-MS/MS). Based on the products identified, detailed transformation pathways for SSZ degradation in the UV/PDS system were proposed. Results reveal that UV/PDS could be an efficient approach for remediation of water

  16. Biobased Nanoparticles for Broadband UV Protection with Photostabilized UV Filters

    NARCIS (Netherlands)

    Hayden, D.R.|info:eu-repo/dai/nl/412640694; Imhof, A.|info:eu-repo/dai/nl/145641600; Velikov, K. P.|info:eu-repo/dai/nl/239483472

    2016-01-01

    Sunscreens rely on multiple compounds to provide effective and safe protection against UV radiation. UV filters in sunscreens, in particular, provide broadband UV protection but are heavily linked to adverse health effects due to the generation of carcinogenic skin-damaging reactive oxygen species

  17. Effects of UV radiation on phytoplankton

    Science.gov (United States)

    Smith, Raymond C.; Cullen, John J.

    1995-07-01

    It is now widely documented that reduced ozone will result in increased levels of ultraviolet (UV) radiation, especially UV-B (280-320nm), incident at the surface of the earth [Watson, 1988; Anderson et al., 1991; Schoeberl and Hartmann, 1991; Frederick and Alberts, 1991; WMO, 1991; Madronich, 1993; Kerr and McElroy, 1993], and there is considerable and increasing evidence that these higher levels of UV-B radiation may be detrimental to various forms of marine life in the upper layers of the ocean. With respect to aquatic ecosystems, we also know that this biologically- damaging mid-ultraviolet radiation can penetrate to ecologically- significant depths in marine and freshwater systems [Jerlov, 1950; Lenoble, 1956; Smith and Baker, 1979; Smith and Baker, 1980; Smith and Baker, 1981; Kirk et al., 1994]. This knowledge, plus the dramatic decline in stratospheric ozone over the Antarctic continent each spring, now known to be caused by anthropogenically released chemicals [Solomon, 1990; Booth et al., 1994], has resulted in increased UV-environmental research and a number of summary reports. The United Nations Environmental Program (UNEP) has provided recent updates with respect to the effects of ozone depletion on aquatic ecosystems (Hader, Worrest, Kumar in UNEP 1989, 1991, Hader, Worrest, Kumar and Smith UNEP 1994) and the Scientific Committee on Problems of the Environment (SCOPE) has provided [SCOPE, 1992] a summary of the effects of increased UV radiation on biological systems. SCOPE has also reported [SCOPE, 1993] on the effects of increased UV on the biosphere. In addition, several books have recently been published reviewing various aspects of environmental UV photobiology [Young et al., 1993], UV effects on humans, animals and plants [Tevini, 1993], the biological effects of UV radiation in Antarctica [Weiler and Penhale, 1994], and UV research in freshwater ecosystems [Williamson and Zagarese, 1994]. Several other reviews are relevant [NAS, 1984; Caldwell

  18. Optimizing UV Index determination from broadband irradiances

    Science.gov (United States)

    Tereszchuk, Keith A.; Rochon, Yves J.; McLinden, Chris A.; Vaillancourt, Paul A.

    2018-03-01

    A study was undertaken to improve upon the prognosticative capability of Environment and Climate Change Canada's (ECCC) UV Index forecast model. An aspect of that work, and the topic of this communication, was to investigate the use of the four UV broadband surface irradiance fields generated by ECCC's Global Environmental Multiscale (GEM) numerical prediction model to determine the UV Index. The basis of the investigation involves the creation of a suite of routines which employ high-spectral-resolution radiative transfer code developed to calculate UV Index fields from GEM forecasts. These routines employ a modified version of the Cloud-J v7.4 radiative transfer model, which integrates GEM output to produce high-spectral-resolution surface irradiance fields. The output generated using the high-resolution radiative transfer code served to verify and calibrate GEM broadband surface irradiances under clear-sky conditions and their use in providing the UV Index. A subsequent comparison of irradiances and UV Index under cloudy conditions was also performed. Linear correlation agreement of surface irradiances from the two models for each of the two higher UV bands covering 310.70-330.0 and 330.03-400.00 nm is typically greater than 95 % for clear-sky conditions with associated root-mean-square relative errors of 6.4 and 4.0 %. However, underestimations of clear-sky GEM irradiances were found on the order of ˜ 30-50 % for the 294.12-310.70 nm band and by a factor of ˜ 30 for the 280.11-294.12 nm band. This underestimation can be significant for UV Index determination but would not impact weather forecasting. Corresponding empirical adjustments were applied to the broadband irradiances now giving a correlation coefficient of unity. From these, a least-squares fitting was derived for the calculation of the UV Index. The resultant differences in UV indices from the high-spectral-resolution irradiances and the resultant GEM broadband irradiances are typically within 0

  19. Zinc finger protein 598 inhibits cell survival by promoting UV-induced apoptosis.

    Science.gov (United States)

    Yang, Qiaohong; Gupta, Romi

    2018-01-19

    UV is one of the major causes of DNA damage induced apoptosis. However, cancer cells adopt alternative mechanisms to evade UV-induced apoptosis. To identify factors that protect cancer cells from UV-induced apoptosis, we performed a genome wide short-hairpin RNA (shRNA) screen, which identified Zinc finger protein 598 (ZNF598) as a key regulator of UV-induced apoptosis. Here, we show that UV irradiation transcriptionally upregulates ZNF598 expression. Additionally, ZNF598 knockdown in cancer cells inhibited UV-induced apoptosis. In our study, we observe that ELK1 mRNA level as well as phosphorylated ELK1 levels was up regulated upon UV irradiation, which was necessary for UV irradiation induced upregulation of ZNF598. Cells expressing ELK1 shRNA were also resistant to UV-induced apoptosis, and phenocopy ZNF598 knockdown. Upon further investigation, we found that ZNF598 knockdown inhibits UV-induced apoptotic gene expression, which matches with decrease in percentage of annexin V positive cell. Similarly, ectopic expression of ZNF598 promoted apoptotic gene expression and also increased annexin V positive cells. Collectively, these results demonstrate that ZNF598 is a UV irradiation regulated gene and its loss results in resistance to UV-induced apoptosis.

  20. Semi-conservative synthesis of DNA in UV-sensitive mutant cells of Chinese hamster after UV-irradiation

    International Nuclear Information System (INIS)

    Vikhanskaya, F.L.; Khrebtukova, I.A.; Manuilova, E.S.

    1985-01-01

    A study was made of the rate of semi-conservative DNA synthesis in asynchronous UV-resistant (clone V79) and UV-sensitive clones (VII and XII) of Chinese hamster cells after UV-irradiation. In all 3 clones studied, UV-irradiation (5-30 J/m 2 ) induced a decrease in the rate of DNA synthesis during the subsequent 1-2 h. In the resistant clone (V79) recovery of DNA synthesis rate started after the first 2 h post-irradiation (5 J/m 2 ) and by the 3rd hour reached its maximum value, which constituted 70% of that observed in control, non-irradiated cells. The UV-sensitive mutant clones VII and XII showed no recovery in the rate of DNA synthesis during 6-7 h post-irradiation. The results obtained show that the survival of cells is correlated with the ability of DNA synthesis to recover after UV-irradiation in 3 clones studied. The observed recovery of UV-inhibited DNA synthesis in mutant clones may be due to certain defects in DNA repair. (orig.)

  1. Wastewater disinfection with peracetic acid and UV

    International Nuclear Information System (INIS)

    Caretti, C.; Lubello, C.

    2001-01-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm - 2 is enough to meet the Italian limit [it

  2. Standardization of UV LED measurements

    Science.gov (United States)

    Eppeldauer, G. P.; Larason, T. C.; Yoon, H. W.

    2015-09-01

    Traditionally used source spectral-distribution or detector spectral-response based standards cannot be applied for accurate UV LED measurements. Since the CIE standardized rectangular-shape spectral response function for UV measurements cannot be realized with small spectral mismatch when using filtered detectors, the UV measurement errors can be several times ten percent or larger. The UV LEDs produce broadband radiation and both their peaks or spectral bandwidths can change significantly. The detectors used for the measurement of these LEDs also have different spectral bandwidths. In the discussed example, where LEDs with 365 nm peak are applied for fluorescent crack-recognition using liquid penetrant (non-destructive) inspection, the broadband radiometric LED (signal) measurement procedure is standardized. A UV LED irradiance-source was calibrated against an FEL lamp standard to determine its spectral irradiance. The spectral irradiance responsivity of a reference UV meter was also calibrated. The output signal of the reference UV meter was calculated from the spectral irradiance of the UV source and the spectral irradiance responsivity of the reference UV meter. From the output signal, both the integrated irradiance (in the reference plane of the reference meter) and the integrated responsivity of the reference meter were determined. Test UV meters calibrated for integrated responsivity against the reference UV meter, can be used to determine the integrated irradiance from a field UV source. The obtained 5 % (k=2) measurement uncertainty can be decreased when meters with spectral response close to a constant value are selected.

  3. Health hazards of UV radiation

    International Nuclear Information System (INIS)

    Matthes, R.

    1994-01-01

    The author describes the effects and health risks of UV exposure. This includes UV effects on the DNS, the eyes, the immune system, and the skin. Finally, recommendations are given for protection against excessive UV exposure on the basis of the IRPA/INIRC guidelines. (orig.) [de

  4. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

    Small, D.W.; Wong, R.K.; Colson, W.B.

    1995-01-01

    In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium's UV FEL

  5. Comparison of UV-C and Pulsed UV Light Treatments for Reduction of Salmonella, Listeria monocytogenes, and Enterohemorrhagic Escherichia coli on Eggs.

    Science.gov (United States)

    Holck, Askild L; Liland, Kristian H; Drømtorp, Signe M; Carlehög, Mats; McLEOD, Anette

    2018-01-01

    Ten percent of all strong-evidence foodborne outbreaks in the European Union are caused by Salmonella related to eggs and egg products. UV light may be used to decontaminate egg surfaces and reduce the risk of human salmonellosis infections. The efficiency of continuous UV-C (254 nm) and pulsed UV light for reducing the viability of Salmonella Enteritidis, Listeria monocytogenes, and enterohemorrhagic Escherichia coli on eggs was thoroughly compared. Bacterial cells were exposed to UV-C light at fluences from 0.05 to 3.0 J/cm 2 (10 mW/cm 2 , for 5 to 300 s) and pulsed UV light at fluences from 1.25 to 18.0 J/cm 2 , resulting in reductions ranging from 1.6 to 3.8 log, depending on conditions used. Using UV-C light, it was possible to achieve higher reductions at lower fluences compared with pulsed UV light. When Salmonella was stacked on a small area or shielded in feces, the pulsed UV light seemed to have a higher penetration capacity and gave higher bacterial reductions. Microscopy imaging and attempts to contaminate the interior of the eggs with Salmonella through the eggshell demonstrated that the integrity of the eggshell was maintained after UV light treatments. Only minor sensory changes were reported by panelists when the highest UV doses were used. UV-C and pulsed UV light treatments appear to be useful decontamination technologies that can be implemented in continuous processing.

  6. Chemical and UV Mutagenesis.

    Science.gov (United States)

    Bose, Jeffrey L

    2016-01-01

    The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.

  7. coating layers under the UV loading

    Directory of Open Access Journals (Sweden)

    Kulhavý Petr

    2017-01-01

    Full Text Available For individual components as well as for the final products is need to determine their resistance and other mechanical properties, which can be changing due to the various conditions and simultaneously we try to get still closer to the real operating conditions.Currently, given the need to guarantee a perfect quality of the product throughout its entire life cycle, it is necessary to assess the protective layers that are in direct contact with the material itself or with the future products.This article presents the results of testing individual components of the selected materials and their resistance to the UV rays. These were some samples of a prelacquered sheet and a powder coated plate after their forming, next by pigment colored concrete cubes, artificial wood and a prototype sample of the translucent material Licrete. Compared to a conventional climate tests such as heat, cold, humidity or the salt chambers, the colored protection layers were subjected to a strong UV rays. Subsequently was evaluated the change of the colors, brightness and where it was possible also the adhesion parameters and thickness of the coated layer. The measurement wasn’t focused only on the adhesion and color stability, but also to a violation of microstructure due to high temperatures caused by the UV ray. The selected specimens were tested in a device which simulates solar radiation and then were them evaluated the changes of a colors and on the surface structure.

  8. Survival and mutation in clones derived from V79 Chinese hamster cells irradiated with multiple small exposures to far-UV and mid-UV

    International Nuclear Information System (INIS)

    Ikebuchi, M.; Osmak, M.; Hill, C.

    1987-01-01

    Clones were isolated from U81 and N80 cells that were established by irradiation of Chinese hamster V79-M12G cells on a once a day schedule with 81 and 80 fractions of 6 J m/sup -2/ far-UV and 150 Jm/sup -2/ mid-UV (UV-B), respectively. These clones were examined for UV sensitivity to cell lethality and induction of mutations at 6TG/sup r/ (resistance to 6-thioguanine) and Oua/sup R/ (resistance to ouabain) loci. Survival curves for these clones indicate that their UV sensitivities to lethality vary from that of M12G cells to that of U81 and N80 parental cells. Clones also show heterogeneity for mutability to mid-UV: For induction of 6TG/sup r/, for example, non-mutable (U814), hypomutable (U815) and hypermutable (U811) were isolated from U81 cells. The authors are investigating by chromosome analysis and repair experiments why resistance to far-UV and mid-UV cell killing in these cells appears to be induced but the resulting survivors have a heterogeneous response to mutation induction by further doses of UV light

  9. The repair of low dose UV light-induced damage to human skin DNA in condition of trace amount Mg 2+

    Science.gov (United States)

    Gao, Fang; Guo, Zhouyi; Zheng, Changchun; Wang, Rui; Liu, Zhiming; Meng, Pei; Zhai, Juan

    2008-12-01

    Ultraviolet light-induced damage to human skin DNA was widely investigated. The primary mechanism of this damage contributed to form cyclobutane pyrimidine dimmers (CPDs). Although the distribution of UV light-induced CPDs within a defined sequence is similar, the damage in cellular environment which shields the nuclear DNA was higher than that in organism in apparent dose. So we use low UVB light as main study agent. Low dose UV-irradiated HDF-a cells (Human Dermal Fibroblasts-adult cells) which is weaker than epidermic cells were cultured with DMEM at different trace amount of Mg2+ (0mmol/L , 0.1mmol/L , 0.2mmol/L, 0.4mmol/L, 0.8mmol/L, 1.2mmol/L) free-serum DMEM and the repair of DNA strands injured were observed. Treat these cells with DNA strand breaks detection, photoproducts detection and the repair of photoproducts detection. Then quantitate the role of trace amount Mg2+ in repair of UV light-induced damage to human skin. The experiment results indicated that epidermic cells have capability of resistance to UV-radiation at a certain extent. And Mg2+ can regulate the UV-induced damage repair and relative vitality. It can offer a rationale and experiment data to relieve UV light-induced skin disease.

  10. Improvement of lipid production by the oleaginous yeast Rhodosporidium toruloides through UV mutagenesis.

    Science.gov (United States)

    Yamada, Ryosuke; Kashihara, Tomomi; Ogino, Hiroyasu

    2017-05-01

    Oleaginous yeasts are considered a promising alternative lipid source for biodiesel fuel production. In this study, we attempted to improve the lipid productivity of the oleaginous yeast Rhodosporidium toruloides through UV irradiation mutagenesis and selection based on ethanol and H 2 O 2 tolerance or cerulenin, a fatty acid synthetase inhibitor. Glucose consumption, cell growth, and lipid production of mutants were evaluated. The transcription level of genes involved in lipid production was also evaluated in mutants. The ethanol and H 2 O 2 tolerant strain 8766 2-31M and the cerulenin resistant strain 8766 3-11C were generated by UV mutagenesis. The 8766 2-31M mutant showed a higher lipid production rate, and the 8766 3-11C mutant produced a larger amount of lipid and had a higher lipid production rate than the wild type strain. Transcriptional analysis revealed that, similar to the wild type strain, the ACL1 and GND1 genes were expressed at significantly low levels, whereas IDP1 and ME1 were highly expressed. In conclusion, lipid productivity in the oleaginous yeast R. toruloides was successfully improved via UV mutagenesis and selection. The study also identified target genes for improving lipid productivity through gene recombination.

  11. Light Conversion and Scattering in UV Protective Textiles

    Directory of Open Access Journals (Sweden)

    Grancarić Ana Marija

    2014-12-01

    Full Text Available The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80% of UV-R gets absorbed, whilst in the remaining 20% gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA, UV-B protective agents, as well as nanoparticles, if applied. Based on electronically excited state by energy of UV-R (usually 340-370 nm, the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420-470 nm of the spectrum. By absorbing UV-A radiation, optical brightened fabrics transform this radiation into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, is very resistant to washing and improves the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene-derived FWAs were applied on cotton fabric in wide concentration

  12. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    Energy Technology Data Exchange (ETDEWEB)

    Spiliotopoulou, Aikaterini [Water ApS, Farum Gydevej 64, 3520 Farum (Denmark); Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Hansen, Kamilla M.S., E-mail: kmsh@env.dtu.dk [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Andersen, Henrik R. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark)

    2015-07-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  13. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    International Nuclear Information System (INIS)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M.S.; Andersen, Henrik R.

    2015-01-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  14. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

    Full Text Available UV radiation (UV is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

  15. Despite higher body fat content, Ecuadorian subjects with Laron syndrome have less insulin resistance and lower incidence of diabetes than their relatives.

    Science.gov (United States)

    Guevara-Aguirre, Jaime; Procel, Patricio; Guevara, Carolina; Guevara-Aguirre, Marco; Rosado, Verónica; Teran, Enrique

    2016-06-01

    In the present pandemics of obesity and insulin resistant diabetes mellitus (DM), the specific contribution of etiological factors such as shifts in nutritional and exercise patterns, genetic and hormonal, is subject of ongoing research. Among the hormonal factors implicated, we selected obesity-driven insulin resistance for further evaluation. It is known that growth hormone (GH) has profound effects on carbohydrate metabolism. In consequence, we compared the effects of the lack of the counter-regulatory effects of GH, in a group of subjects with GH receptor deficiency (GHRD) due to a mutated GH receptor vs. that of their normal relatives. It was found that, despite their obesity, subjects with GHRD, have diminished incidence of diabetes, lower glucose and insulin concentrations, and lower values of indexes indicative of insulin resistance such as HOMA-IR. The GHRD subjects were also capable of appropriately handling glucose or mixed meal loads despite diminished insulin secretion. These observations allow us to suggest that the association of obesity with increased risk for diabetes appears to be dependent on intact growth hormone signaling. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Effect of ultraviolet illumination on metal oxide resistive memory

    KAUST Repository

    Duran Retamal, Jose Ramon

    2014-12-22

    We investigate the photoelectrical and resistive switching properties of Pt/ZnO/Pt capacitor operated in unipolar mode under ultraviolet (UV) illumination. The oxygen photodesorption under UV illumination explains the photoconduction observed in initial and high resistance states. Meanwhile, oxygen readsorption at surface-related defects justifies the different photoresponses dynamics in both states. Finally, UV illumination significantly reduces the variations of resistance in high resistance state, set voltage and reset voltage by 58%, 33%, and 25%, respectively, stabilizing Pt/ZnO/Pt capacitor. Our findings in improved switching uniformity via UV light give physical insight into designing resistive memory devices.

  17. Effect of ultraviolet illumination on metal oxide resistive memory

    KAUST Repository

    Duran Retamal, Jose Ramon; Kang, Chen-Fang; Ho, Chih-Hsiang; Ke, Jr-Jian; Chang, Wen-Yuan; He, Jr-Hau

    2014-01-01

    We investigate the photoelectrical and resistive switching properties of Pt/ZnO/Pt capacitor operated in unipolar mode under ultraviolet (UV) illumination. The oxygen photodesorption under UV illumination explains the photoconduction observed in initial and high resistance states. Meanwhile, oxygen readsorption at surface-related defects justifies the different photoresponses dynamics in both states. Finally, UV illumination significantly reduces the variations of resistance in high resistance state, set voltage and reset voltage by 58%, 33%, and 25%, respectively, stabilizing Pt/ZnO/Pt capacitor. Our findings in improved switching uniformity via UV light give physical insight into designing resistive memory devices.

  18. UV-A enhanced growth and UV-B induced positive effects in the recovery of photochemical yield in Gracilaria lemaneiformis (Rhodophyta).

    Science.gov (United States)

    Xu, Juntian; Gao, Kunshan

    2010-09-02

    The effects of solar UV radiation (280-400 nm) on growth, quantum yield and pigmentation in Gracilaria lemaneiformis were investigated when the thalli were cultured under solar radiation with or without UV for a period of 15 days. Presence of UV-A (315-400 nm) enhanced the relative growth rate, while UV-B (218-315 nm) inhibited it. The positive effect of UV-A and negative effect of UV-B counteracted to result in an insignificant impact of UVR on growth. During the noon period, both UV-A and UV-B resulted in the decrease of maximum quantum yield (Fv/Fm), but UV-B aided in the recovery of the yield in the late afternoon, reflecting that UV-B might be used as a signal in photorepair processes. UV induced the accumulation of UV-absorbing compounds (UVAC) to defend against the harmful UVR. However, the accumulation of UVAC took a much longer time compared to that previously reported, which was probably due to the lower levels of solar radiation and water temperature in the early spring period. Unknown UV-absorbing compounds (UVAC), which peaked at 265 nm, probably the precursor of MAAs (UVAC(325)), accumulated under moderate levels of solar radiation and were transformed to MAAs under higher solar radiation. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  19. All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink

    Science.gov (United States)

    Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

    2016-01-01

    We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the Cu nano-films. Optimally sintered Cu nano-ink films produced using a deep UV-assisted flash white light sintering technique had the lowest resistivity (7.62 μΩ·cm), which was only 4.5-fold higher than that of bulk Cu film (1.68 μΩ•cm). PMID:26806215

  20. Reasons of chlorella strain's resistance to physical and chemical factors of environment

    Energy Technology Data Exchange (ETDEWEB)

    Apasheva, L M; Bujiashvilie, D M; Naydich, V I; Shevchenko, V A

    1979-07-01

    Under environmental pollution it is necessary to study the reasons of an organism's resistance as well as the specificity of it. Some chlorella strains were under the influence of uv- and x-irradiation, heat treatment, cadmium salts, insecticide, and detergent. It was shown that cells which were resistant to physical factors were resistant to chemical intoxication, as well. The positive correlation between resistance of strains and the described influences and the levels of endogenic thiols was found. The second reason for higher resistance is an increase of free radicals' concentration. It is linked with increasing P/sub 700/ quantity of electron-transport chains that make possible higher levels of photosynthetic reactions of resistant cells.

  1. uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

    Science.gov (United States)

    Chae, S K; Kafer, E

    1993-01-01

    Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

  2. UV-B Perception and Acclimation in Chlamydomonas reinhardtii[OPEN

    Science.gov (United States)

    Chappuis, Richard; Allorent, Guillaume

    2016-01-01

    Plants perceive UV-B, an intrinsic component of sunlight, via a signaling pathway that is mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8) and induces UV-B acclimation. To test whether similar UV-B perception mechanisms exist in the evolutionarily distant green alga Chlamydomonas reinhardtii, we identified Chlamydomonas orthologs of UVR8 and the key signaling factor CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). Cr-UVR8 shares sequence and structural similarity to Arabidopsis thaliana UVR8, has conserved tryptophan residues for UV-B photoreception, monomerizes upon UV-B exposure, and interacts with Cr-COP1 in a UV-B-dependent manner. Moreover, Cr-UVR8 can interact with At-COP1 and complement the Arabidopsis uvr8 mutant, demonstrating that it is a functional UV-B photoreceptor. Chlamydomonas shows apparent UV-B acclimation in colony survival and photosynthetic efficiency assays. UV-B exposure, at low levels that induce acclimation, led to broad changes in the Chlamydomonas transcriptome, including in genes related to photosynthesis. Impaired UV-B-induced activation in the Cr-COP1 mutant hit1 indicates that UVR8-COP1 signaling induces transcriptome changes in response to UV-B. Also, hit1 mutants are impaired in UV-B acclimation. Chlamydomonas UV-B acclimation preserved the photosystem II core proteins D1 and D2 under UV-B stress, which mitigated UV-B-induced photoinhibition. These findings highlight the early evolution of UVR8 photoreceptor signaling in the green lineage to induce UV-B acclimation and protection. PMID:27020958

  3. Moving towards Freirean Critical Pedagogy: Redefining Competence-based Curricula through Participatory Action Research as Resistance to the Neoliberalization of Higher Education in Spain

    Directory of Open Access Journals (Sweden)

    Ana Fernández-Aballí Altamirano

    2015-07-01

    Full Text Available The neoliberalization of higher education in Spain has been consolidating through its integration process to the European Higher Education Area. In this context, competence-based curricula have become an instrument to create a model of education and citizenship in which market values override solidarity, justice and community well-being. There is, however, still room to shift the teaching-learning space. Using Freirean critical pedagogy to redefine the curriculum through the implementation of Participatory Action Research (PAR in the classroom provides a methodological approach within and despite current EHEA policies to revert the neoliberalization of higher education.

  4. New technologies for UV detectors

    Science.gov (United States)

    Joseph, C. L.

    1993-01-01

    Several technologies are currently being developed, leading to substantial improvements in the performance of UV detectors or significant reductions in power or weight. Four technologies discussed are (1) thin-film coatings to enhance the UV sensitivity of CCD's, (2) highly innovative magnet assemblies that dramatically reduce weight and result in virtually no external flux, (3) new techniques for curving microchannel plates (MCP's) so that single plates can be used to prevent ion feedback and present highly localized charge clouds to an anode structure, and (4) high-performance alternatives to glass-based MCP's. In item (2), for example, very robust magnets are made out of rare earth materials such as samarium cobalt, and cladding magnets are employed to prevent flux from escaping from the detector into the external environment. These new ultralight magnet assemblies are able to create strong, exceptionally uniform magnetic fields for image intensification and focusing of photoelectrons. The principle advantage of such detectors is the quantum efficiencies of 70-80 percent obtained throughout ultraviolet wavelengths (900-2000 A), the highest of any device. Despite the improvements achieved under item (3), high-performance alternatives to conventional glass-based MCP's potentially offer three distinct new advantages that include (1) a 30-100-fold improvement in dynamic range resulting in correspondingly higher signal-to-noise ratios, (2) the use of pure dielectric and semiconductor materials that will not outgas contaminants that eventually destroy photocathodes, and (3) channels that have constant spacing providing long-ranged order since the plates are made using photolithography techniques from the semiconductor industry. The manufacturers of these advanced-technology MCP's, however, are a couple of years away from actually producing a functioning image intensifier. In contrast to the use of CCD's for optical, ground based observations, there is no single

  5. UV-inducible DNA repair in Acinetobacter calcoaceticus

    International Nuclear Information System (INIS)

    Berenstein, D.

    1987-01-01

    Bacterial mutation frequency after UV irradiation and phage mutation frequency under conditions of W-reactivation were determined in A. calcoaceticus. With the exception of streptomycin resistance, there was no increase in the frequency of the assayed markers above the background level. The increased survival of phage during W-reactivation was not followed by an increase in the frequency of mutation from turbid to clear plaque formers among phage survivors. The findings suggested that the UV-inducible repair pathway in A. calcoaceticus was error free. Post-irradiation incubation of UV-treated culture before phage infection resulted in a further increase of W-reactivation. As chloramphenicol inhibited this response, it was concluded that de novo protein synthesis was involved in the UV-inducible repair pathway in A. calcoaceticus. (Auth.)

  6. Uvs Nuur, Mongolia

    Science.gov (United States)

    2007-01-01

    The Uvs Nuur Basin in Mongolia and the Russian Federation is the northernmost of the enclosed basins of Central Asia. It takes its name from Uvs Nuur Lake, a large, shallow and very saline lake, very important for migrating birds. Inscribed as a UNESCO World Heritage Site in 2003, the site is made up of twelve protected areas representing major biomes of eastern Eurasia. The steppe ecosystem supports a rich diversity of birds and the desert is home to a number of rare gerbil, jerboas and the marbled polecat. The mountains are an important refuge for the endangered snow leopard, mountain sheep, and the Asiatic ibex. The image covers an area of 46 x 47.8 km, was acquired on September 4, 2001, and is located near 50.3 degrees north latitude, 90.7 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  7. UV curable aqueous dispersions for wood coatings

    International Nuclear Information System (INIS)

    Peeters, S.; Bleus, J.P.; Wang, Z.J.; Arceneaux, J. A.; Hall, J.

    1999-01-01

    In this paper the characterisation of aqueous dispersions of UV curable resins is described. Two types of dispersions were used: dispersions that are tacky after water evaporation and tack - free before cure dispersions. The physical and rheological properties of these products have been determined and the performance of these dispersions in various formulations, especially for wood applications has been studied. With these dispersions, it is possible to produce coatings having a good cure speed, good surface hardness and good solvent -, chemical - and water resistance

  8. CUVE - Cubesat UV Experiment: Unveil Venus' UV Absorber with Cubesat UV Mapping Spectrometer

    Science.gov (United States)

    Cottini, V.; Aslam, S.; D'Aversa, E.; Glaze, L.; Gorius, N.; Hewagama, T.; Ignatiev, N.; Piccioni, G.

    2017-09-01

    Our Venus mission concept Cubesat UV Experiment (CUVE) is one of ten proposals selected for funding by the NASA PSDS3 Program - Planetary Science Deep Space SmallSat Studies. CUVE concept is to insert a CubeSat spacecraft into a Venusian orbit and perform remote sensing of the UV spectral region using a high spectral resolution point spectrometer to resolve UV molecular bands, observe nightglow, and characterize the unidentified main UV absorber. The UV spectrometer is complemented by an imaging UV camera with multiple bands in the UV absorber main band range for contextual imaging. CUVE Science Objectives are: the nature of the "Unknown" UV-absorber; the abundances and distributions of SO2 and SO at and above Venus's cloud tops and their correlation with the UV absorber; the atmospheric dynamics at the cloud tops, structure of upper clouds and wind measurements from cloud-tracking; the nightglow emissions: NO, CO, O2. This mission will therefore be an excellent platform to study Venus' cloud top atmospheric properties where the UV absorption drives the planet's energy balance. CUVE would complement past, current and future Venus missions with conventional spacecraft, and address critical science questions cost effectively.

  9. Reductone effect on UV-irradiated starved E. coli cells

    International Nuclear Information System (INIS)

    Felzenszwalb, I.; Gomes, R.A.

    1982-01-01

    A starvation-induced resistence enhancement (SIRE) to UV and reductone treatments was observed in repair-profient E. coli cells. The UV-reductone positive interaction, which is possibly related to excision repair mechanisms, was not modified by prestarvation when all cells in culture had completed their round of DNA replication. In irradiated prestarved reductone-treated cells, a decrease in the DNA degradation rate was detected after the removal of reductone and the induction of a lower number of DNA single-strand breaks. The induction kinectics of DNA single-strand breaks in prestarved UV-irradiated and the repair kinetics of these lesions are slower than in non-starved cells. The resistance enhancement demonstrated under these conditions could be justified either by the generation of fewer doubles strand breaks during repair or by the possibility of repair of these lesions. (Author) [pt

  10. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Science.gov (United States)

    Zempila, Melina-Maria; van Geffen, Jos H. G. M.; Taylor, Michael; Fountoulakis, Ilias; Koukouli, Maria-Elissavet; van Weele, Michiel; van der A, Ronald J.; Bais, Alkiviadis; Meleti, Charikleia; Balis, Dimitrios

    2017-06-01

    UV doses were found to be ˜ 12.5 % higher than the NILU NN estimates but, despite the presence of a visually apparent seasonal pattern, the R2 values were found to be robustly high and equal to 0.92-0.93 for 1588 all-sky coincidences. These results significantly improve when limiting the dataset to cloud-free days with differences of 0.57 % for the erythemal doses, 1.22 % for the vitamin D doses, and 1.18 % for the DNA-damage doses, with standard deviations of the order of 11-13 %. The improvement of the comparative statistics under cloud-free cases further testifies to the importance of the appropriate consideration of the contribution of clouds in the UV radiation reaching the Earth's surface. For the urban area of Thessaloniki, with highly variable aerosol, the weakness of the implicit aerosol information introduced to the TEMIS UV dose algorithm was revealed by comparison of the datasets to aerosol optical depths at 340 nm as reported by a collocated CIMEL sun photometer, operating in Thessaloniki at LAP/AUTh as part of the NASA Aerosol Robotic Network.

  11. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    M.-M. Zempila

    2017-06-01

    (lat  ×  long grid cells. TEMIS UV doses were found to be ∼ 12.5 % higher than the NILU NN estimates but, despite the presence of a visually apparent seasonal pattern, the R2 values were found to be robustly high and equal to 0.92–0.93 for 1588 all-sky coincidences. These results significantly improve when limiting the dataset to cloud-free days with differences of 0.57 % for the erythemal doses, 1.22 % for the vitamin D doses, and 1.18 % for the DNA-damage doses, with standard deviations of the order of 11–13 %. The improvement of the comparative statistics under cloud-free cases further testifies to the importance of the appropriate consideration of the contribution of clouds in the UV radiation reaching the Earth's surface. For the urban area of Thessaloniki, with highly variable aerosol, the weakness of the implicit aerosol information introduced to the TEMIS UV dose algorithm was revealed by comparison of the datasets to aerosol optical depths at 340 nm as reported by a collocated CIMEL sun photometer, operating in Thessaloniki at LAP/AUTh as part of the NASA Aerosol Robotic Network.

  12. Differential responses of tetrasporophytes and gametophytes of Mazzaella laminarioides (Gigartinales, Rhodophyta) under solar UV radiation.

    Science.gov (United States)

    Navarro, Nelso P; Figueroa, Félix L; Korbee, Nathalie; Mansilla, Andrés; Plastino, Estela M

    2016-06-01

    The effects of solar UV radiation on mycosporine-like amino acids (MAAs), growth, photosynthetic pigments (Chl a, phycobiliproteins), soluble proteins (SP), and C and N content of Mazzaella laminarioides tetrasporophytes and gametophytes were investigated. Apical segments of tetrasporophytes and gametophytes were exposed to solar radiation under three treatments (PAR [P], PAR+UVA [PA], and PAR+UVA+UVB [PAB]) during 18 d in spring 2009, Punta Arenas, Chile. Samples were taken after 2, 6, 12, and 18 d of solar radiation exposure. Most of the parameters assessed on M. laminarioides were significantly influenced by the radiation treatment, and both gametophytes and tetrasporophytes seemed to respond differently when exposed to high UV radiation. The two main effects promoted by UV radiation were: (i) higher synthesis of MAAs in gametophytes than tetrasporophytes at 2 d, and (ii) a decrease in phycoerythrin, phycocyanin, and SPs, but an increase in MAA content in tetrasporophytes at 6 and 12 d of culture. Despite some changes that were observed in biochemical parameters in both tetrasporophytes and gametophytes of M. laminarioides when exposed to UVB radiation, these changes did not promote deleterious effects that might interfere with the growth in the long term (18 d). The tolerance and resistance of M. laminarioides to higher UV irradiance were expected, as this intertidal species is exposed to variation in solar radiation, especially during low tide. © 2016 Phycological Society of America.

  13. The responses to supplementary of UV radiation of some temperate meadow species

    International Nuclear Information System (INIS)

    Cooley, N.M.

    2002-01-01

    Full text: The growth and development of various meadow species was monitored while growing under enhanced UV-radiation in the natural light environment. Growth responses to supplementary ultraviolet-B (UV-B+A) and ultraviolet-A (UV-A) were compared to the ambient daylight treatment for Bellis perennis, Cardamine pratensis, Cynosurus critatus and Ranunculus ficaria. When the response of ultraviolet A (UV-A) treated plants were compared with those of the UV-B+A, differences were found which varied according to the species and parameter investigated. To further understand the growth responses of the UV-A treatment and their relationship to the UV-B responses polychromatic action spectra in the natural environment was employed B perennis had an action maximum in the UV B (280-315 nm) while C cristatus demonstrates no action in the UV-B but action in the UV-A region (315-400 nm.). To enable further explanation of the effects of elevated UV radiation on the meadow plants Arabidopsis thaliana ecotypes and mutants were investigated. A thaliana ecotypes dry weight accumulation was found to respond differently to the UV treatments. UV B+A treatment was found to inhibit dry weight accumulation in most ecotypes. When UV B+A induced inhibition was expressed in terms of ambient growth rate for each ecotype a linear relationship could be derived. The higher the growth rate the more susceptible the ecotype was to UV-B+A inhibition. The pertinence of the UV-A treatment and UV protocol is discussed. It is suggested that UV responses could alter the diversity of the meadow equilibrium

  14. Replication of UV-irradiated DNA in human cell extracts: Evidence for mutagenic bypass of pyrimidine dimers

    International Nuclear Information System (INIS)

    Thomas, D.C.; Kunkel, T.A.

    1993-01-01

    The authors have examined the efficiency and fidelity of simian virus 40-origin-dependent replication of UV-irradiated double-stranded DNA in extracts of human cells. Using as a mutational target the α-complementation domain of the Escherichia coli lacZ gene in bacteriophage M13mp2DNA, replication of undamaged DNA in HeLa cell extracts was highly accurate, whereas replication of DNA irradiated with UV light (280-320 nm) was both less efficient and less accurate. Replication was inhibited by irradiation in a dose-dependent manner. Nonetheless, covalently closed, monomer-length circular products were generated that were resistant to digestion by Dpn I, showing that they resulted from semiconservative replication. These products were incised by T4 endonuclease V, whereas the undamaged replication products were not, suggesting that pyrimidine dimers were bypassed during replication. When replicated, UV-irradiated DNA was used to transfect an E. coli α-complementation host strain to score mutant M13mp2 plaques, the mutant plaque frequency was substantially higher than that obtained with either unirradiated, replicated DNA, or unreplicated, UV-irradiated DNA. Both the increased mutagenicity and the inhibition of replication associated with UV irradiation were reversed by treatment of the irradiated DNA with photolyase before replication. Sequence analysis of mutants resulting from replication of UV-irradiated DNA demonstrated that most mutants contained C → T transition errors at dipyrimidine sites. A few mutants contained 1-nt frameshift errors or tandem double CC → TT substitutions. The data are consistent with the interpretation that pyrimidine dimers are bypassed during replication by the multiprotein replication apparatus in human cell extracts and that this bypass is mutagenic primarily via misincorporation of dAMP opposite a cytosine (or uracil) in the dimer. 56 refs., 2 figs., 3 tabs

  15. Targhee Russet: A high yielding dual purpose, long russet potato cultivar having higher protein and vitamin C content and resistance to tuber soft rot

    Science.gov (United States)

    Targhee Russet is a dark-skinned russet potato variety with tubers slightly longer than Russet Burbank. It produces higher total and marketable yields than does Russet Burbank at most of the sites it was tested in the western United States. Tuber dormancy is about 58 days shorter than Russet Burba...

  16. The Politics of Gender Segregation and Women's Access to Higher Education in the Islamic Republic of Iran: The Interplay of Repression and Resistance

    Science.gov (United States)

    Rezai-Rashti, Goli M.

    2015-01-01

    One of the significant achievements of the Islamic Republic of Iran has been the increasing access of women to all levels of education. This paper focuses on women's access to higher education and its unexpected and paradoxical outcomes. Today women in Iran represent over 60% of university students at the undergraduate level. Against the dominant…

  17. Climate Variability, Dissolved Organic Carbon, UV Exposure, and Amphibian Decline

    Science.gov (United States)

    Brooks, P. D.; O'Reilly, C. M.; Diamond, S.; Corn, S.; Muths, E.; Tonnessen, K.; Campbell, D. H.

    2001-12-01

    Increasing levels of UV radiation represent a potential threat to aquatic organisms in a wide range of environments, yet controls on in situ variability on UV exposure are relatively unknown. The primary control on the penetration of UV radiation in surface water environments is the amount of photoreactive dissolved organic carbon (DOC). Consequently, biogeochemical processes that control the cycling of DOC also affect the exposure of aquatic organisms to UV radiation. Three years of monitoring UV extinction and DOC composition in Rocky Mountain, Glacier, Sequoia/ Kings Canyon, and Olympic National Parks demonstrate that the amount of fulvic acid DOC is much more important than the total DOC pool in controlling UV attenuation. This photoreactive component of DOC originates primarily in soil, and is subject both to biogeochemical controls (e.g. temperature, moisture, vegetation, soil type) on production, and hydrologic controls on transport to surface water and consequently UV exposure to aquatic organisms. Both of these controls are positively related to precipitation with greater production and transport associated with higher precipitation amounts. For example, an approximately 20 percent reduction in precipitation from 1999 to 2000 resulted in a 27% - 59% reduction in the amount of photoreactive DOC at three sites in Rocky Mountain National Park. These differences in the amount of hydrophobic DOC result in an increase in UV exposure in the aquatic environment by a factor of 2 or more. Implications of these findings for observed patterns of amphibian decline will be discussed.

  18. UV induced thermoluminescence in rare earth oxide doped phosphors: possible use for UV dosimetry

    International Nuclear Information System (INIS)

    Yeh, S.-M.; Su, C.-S.

    1996-01-01

    UV induced thermoluminescent (TL) phenomena in some phosphors doped with rare earth oxides (Gd 2 O 3 :Eu, Gd 2 O 3 :Tb, Gd 2 O 3 :Dy and Y 2 O 3 :EU) have been investigated. Gd 2 O 3 :Eu and Y 2 O 3 :Eu have been found to possess prominent TL phenomena. A stable high temperature glow peak has been found at 345 o C in the cubic (C type) crystalline structure of Gd 2 O 3 :Eu. A more stable high temperature glow peak has also been found at about 380 o C in Y 2 O 3 :Eu. The sensitivity is high enough to be used as UV sensors. TL phenomena in Gd 2 O 3 :Tb and Gd 2 O 3 :Dy have also been investigated, but their TL intensities are much weaker than that of Gd 2 O 3 :Eu or Y 2 O 3 :Eu. On the other hand, all glow peaks of Gd 2 O 3 :Tb and Gd 2 O 3 :Dy are unstable at room temperature, therefore, Gd 2 O 3 :Tb and Gd 2 O 3 :Dy are not suitable for use as UV detectors. According to the above properties, the C type (cubic) crystalline structure of the Gd 2 O 3 :Eu phosphor seems to possess the potential of being the TL material for UV measurement. The position of the high temperature glow peak depends on the total UV exposure. It locates at about 380 o C when this phosphor was irradiated by 302 nm UV at 2.4 mJ.cm -2 exposure, but it shifts to 345 o C at 19.2 mJ.cm -2 or higher exposure. The response curves of this phosphor for various wavelengths, e.g. 253.7 nm, 302 nm, and 365 nm, were also measured. This phosphor is sensitive enough to measure background UV radiations, such as sunlight, bulb light etc. (author)

  19. Diversity in UV sensitivity and recovery potential among bacterioneuston and bacterioplankton isolates.

    Science.gov (United States)

    Santos, A L; Lopes, S; Baptista, I; Henriques, I; Gomes, N C M; Almeida, A; Correia, A; Cunha, A

    2011-04-01

    To assess the variability in UV-B (280-320 nm) sensitivity of selected bacterial isolates from the surface microlayer and underlying water of the Ria de Aveiro (Portugal) estuary and their ability to recover from previous UV-induced stress. Bacterial suspensions were exposed to UV-B radiation (3·3 W m⁻²). Effects on culturability and activity were assessed from colony counts and (3) H-leucine incorporation rates, respectively. Among the tested isolates, wide variability in UV-B-induced inhibition of culturability (37·4-99·3%) and activity (36·0-98·0%) was observed. Incubation of UV-B-irradiated suspensions under reactivating regimes (UV-A, 3·65 W m⁻²; photosynthetic active radiation, 40 W m⁻²; dark) also revealed diversity in the extent of recovery from UV-B stress. Trends of enhanced resistance of culturability (up to 15·0%) and enhanced recovery in activity (up to 52·0%) were observed in bacterioneuston isolates. Bacterioneuston isolates were less sensitive and recovered more rapidly from UV-B stress than bacterioplankton isolates, showing enhanced reduction in their metabolism during the irradiation period and decreased culturability during the recovery process compared to bacterioplankton. UV exposure can affect the diversity and activity of microbial communities by selecting UV-resistant strains and alter their metabolic activity towards protective strategies. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

  20. UV and cold tolerance of a pigment-producing Antarctic Janthinobacterium sp. Ant5-2

    KAUST Repository

    Mojib, Nazia

    2013-03-20

    In this paper, we describe the UV and cold tolerance of a purple violet pigment (PVP)-producing Antarctic bacterium, Janthinobacterium sp. Ant5-2 (PVP+) and compared its physiological adaptations with a pigmentless mutant strain (PVP-). A spontaneous deletion of vioA that codes for tryptophan monooxygenase, the first gene involved in the biosynthesis of PVP was found in PVP- strain. The PVP- culture exhibited significantly reduced survival during exponential and stationary growth phase following exposure to UVB (320 nm) and UVC (254 nm) (dose range: 0-300 J/m2) when compared to wild-type (PVP+) cultures. In addition, upon biochemical inhibition of pigment synthesis by 2(5H)-furanone, wild-type PVP+ cultures exhibited approximately 50-fold growth reduction at a higher dose (300 J/m2) of UV. Increased resistance to UV was observed upon inducing starvation state in both PVP+ and PVP- cultures. There was 80 % (SD = ±8) reduction in extrapolymeric substance (EPS) production in the PVP- cultures along with a compromised survival to freeze-thaw cycles when compared to the PVP+ cultures. Perhaps synthesis of PVP and EPS are among the key adaptive features that define the survival of this bacterium in Antarctic extreme conditions, especially during austral summer months. © 2013 Springer Japan.

  1. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita

    2016-03-01

    Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

  2. Antioxidant responses in the polar marine sea-ice amphipod Gammarus wilkitzkii to natural and experimentally increased UV levels

    International Nuclear Information System (INIS)

    Krapp, Rupert H.; Bassinet, Thievery; Berge, Jorgen; Pampanin, Daniela M.; Camus, Lionel

    2009-01-01

    Polar marine surface waters are characterized by high levels of dissolved oxygen, seasonally intense UV irradiance and high levels of dissolved organic carbon. Therefore, the Arctic sea-ice habitat is regarded as a strongly pro-oxidant environment, even though its significant ice cover protects the ice-associated (=sympagic) fauna from direct irradiation to a large extent. In order to investigate the level of resistance to oxyradical stress, we sampled the sympagic amphipod species Gammarus wilkitzkii during both winter and summer conditions, as well as exposed specimens to simulated levels of near-natural and elevated levels of UV irradiation. Results showed that this amphipod species possessed a much stronger antioxidant capacity during summer than during winter. Also, the experimental UV exposure showed a depletion in antioxidant defences, indicating a negative effect of UV exposure on the total oxyradical scavenging capacity. Another sympagic organism, Onisimus nanseni, was sampled during summer conditions. When compared to G. wilkitzkii, the species showed even higher antioxidant scavenging capacity.

  3. Differential physiological and biochemical responses of two cyanobacteria Nostoc muscorum and Phormidium foveolarum against oxyfluorfen and UV-B radiation.

    Science.gov (United States)

    Sheeba; Pratap Singh, Vijay; Kumar Srivastava, Prabhat; Mohan Prasad, Sheo

    2011-10-01

    In the present study, degree of tolerance and tolerance strategies of two paddy field cyanobacteria viz. Nostoc muscorum and Phormidium foveolarum against oxyfluorfen (10 and 20 μg ml(-1)) and UV-B (7.2 kJ m(-2)d(-1)) stress were investigated. Oxyfluorfen and UV-B decreased growth, photosynthesis, nutrient uptake, nitrate reductase, acid and alkaline phosphatase activities, which accompanied with the increase in the level of oxidative stress. However, growth was more affected in N. muscorum than P. foveolarum. Antioxidants exhibited differential responses against oxyfluorfen and UV-B stress. Ascorbate and proline levels were higher in P. foveolarum. A protein of 66 kDa was expressed in N. muscorum, however, it was absent in P. foveolarum than those of N. muscorum. Besides this, a protein of 29 kDa appeared in P. foveolarum under all the treatments, but it was present only in control cells of N. muscorum cells. Overall results indicated resistant nature of P. foveolarum against oxyfluorfen and UV-B stress in comparison to N. muscorum. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Cancer cells growing on perfused 3D collagen model produced higher reactive oxygen species level and were more resistant to cisplatin compared to the 2D model.

    Science.gov (United States)

    Liu, Qingxi; Zhang, Zijiang; Liu, Yupeng; Cui, Zhanfeng; Zhang, Tongcun; Li, Zhaohui; Ma, Wenjian

    2018-03-01

    Three-dimensional (3D) collagen scaffold models, due to their ability to mimic the tissue and organ structure in vivo, have received increasing interest in drug discovery and toxicity evaluation. In this study, we developed a perfused 3D model and studied cellular response to cytotoxic drugs in comparison with traditional 2D cell cultures as evaluated by cancer drug cisplatin. Cancer cells grown in perfused 3D environments showed increased levels of reactive oxygen species (ROS) production compared to the 2D culture. As determined by growth analysis, cells in the 3D culture, after forming a spheroid, were more resistant to the cancer drug cisplatin compared to that of the 2D cell culture. In addition, 3D culturing cells showed elevated level of ROS, indicating a physiological change or the formation of a microenvironment that resembles tumor cells in vivo. These data revealed that cellular response to drugs for cells growing in 3D environments are dramatically different from that of 2D cultured cells. Thus, the perfused 3D collagen scaffold model we report here might be a potentially very useful tool for drug analysis.

  5. Photoreactivation and excision repair of UV induced pyrimidine dimers in the unicellular cyanobacterium Gloeocapsa alpicola (Synechocystis PCC 6308)

    International Nuclear Information System (INIS)

    O'Brien, P.A.; Houghton, J.A.

    1982-01-01

    The survival curve obtained after UV irradiation of the unicellular cyanobacterium Synechocystis is typical of a DNA repair competent organism. Inhibition of DNA replication, by incubating cells in the dark, increased resistance to the lethal effects of UV at higher fluences. Exposure of irradiated cells to near ultraviolet light (350-500 nm) restored viability to pre-irradiation levels. In order to measure DNA repair activity, techniques have been developed for the chromatographic analysis of pyrimidine dimers in synechocystis. The specificity of this method was established using a haploid strain of Saccharomyces cerevisiae. In accordance with the physiological responses of irradiated cells to photoreactivating light, pyrimidine dimers were not detected after photoreactivation treatment. Incubation of irradiated cells under non-photoreactivating growth conditions for 15h resulted in complete removal of pyrimidine dimers. It is concluded that Synechocystis contains photoreactivation and excision repair systems for the removal of pyrimidine dimers. (author)

  6. Higher glucose, insulin and insulin resistance (HOMA-IR) in childhood predict adverse cardiovascular risk in early adulthood: the Pune Children's Study.

    Science.gov (United States)

    Yajnik, Chittaranjan S; Katre, Prachi A; Joshi, Suyog M; Kumaran, Kalyanaraman; Bhat, Dattatray S; Lubree, Himangi G; Memane, Nilam; Kinare, Arun S; Pandit, Anand N; Bhave, Sheila A; Bavdekar, Ashish; Fall, Caroline H D

    2015-07-01

    The Pune Children's Study aimed to test whether glucose and insulin measurements in childhood predict cardiovascular risk factors in young adulthood. We followed up 357 participants (75% follow-up) at 21 years of age who had undergone detailed measurements at 8 years of age (glucose, insulin, HOMA-IR and other indices). Oral glucose tolerance, anthropometry, plasma lipids, BP, carotid intima-media thickness (IMT) and arterial pulse wave velocity (PWV) were measured at 21 years. Higher fasting glucose, insulin and HOMA-IR at 8 years predicted higher glucose, insulin, HOMA-IR, BP, lipids and IMT at 21 years. A 1 SD change in 8 year variables was associated with a 0.10-0.27 SD change at 21 years independently of obesity/adiposity at 8 years of age. A greater rise in glucose-insulin variables between 8 and 21 years was associated with higher cardiovascular risk factors, including PWV. Participants whose HOMA-IR measurement remained in the highest quartile (n = 31) had a more adverse cardiovascular risk profile compared with those whose HOMA-IR measurement remained in the lowest quartile (n = 28). Prepubertal glucose-insulin metabolism is associated with adult cardiovascular risk and markers of atherosclerosis. Our results support interventions to improve glucose-insulin metabolism in childhood to reduce cardiovascular risk in later life.

  7. Effects of UV irradiation and UV/chlorine co-exposure on natural organic matter in water

    International Nuclear Information System (INIS)

    Liu, Wei; Zhang, Zaili; Yang, Xin; Xu, Yiyue; Liang, Yongmei

    2012-01-01

    The effects of co-exposure to ultraviolet (UV) irradiation (with either low- or medium-pressure UV lamps) and free chlorine (chloramine) at practical relevant conditions on changes in natural organic matter (NOM) properties were investigated using four waters. The changes were characterized using the specific disinfection by-product formation potential (SDBPFP), specific total organic halogen formation potential (STOXFP), differential UV absorbance (∆UVA), and size-exclusion chromatography (SEC). The results for exposure to UV irradiation alone and for samples with no exposure were also obtained. The SDBPFPs in all UV-irradiated NOM waters observed were higher than those of non-irradiated samples. UV irradiation led to increases in STOXFPs as a result of chlorination, but no changes, or only small decreases, from chloramination. UV irradiation alone led to positive ∆UVA spectra of the four NOM waters; co-exposure to UV and chlorine gave larger negative ∆UVA spectra than those obtained by chlorine exposure alone. No obvious changes in SEC results were observed for samples only irradiated with UV light; co-exposure gave no detectable changes in the abundances of small fractions for exposure to chlorine only. Both UV photooxidation and photocatalytic oxidation appear to affect the reactivity of the NOM toward subsequent chlorination, and the magnitude of the changes is generally greater for medium-pressure lamps than for low-pressure lamps. These results suggest that applying UV disinfection technology to a particular source may not always be disinfection by-product-problem-free, and the interactions between UV light, chlorine, and NOM may need to be considered. - Highlights: ► We discussed the effects of co-exposure to UV light and chlorine on properties of natural organic matters in waters. ► UV irradiation led to increases in SDBPFP and STOXFP of NOM waters from chlorination. ► We suggest that applying an UV disinfection technology to a particular

  8. The Effects of UV Light on the Chemical and Mechanical Properties of a Transparent Epoxy-Diamine System in the Presence of an Organic UV Absorber

    Directory of Open Access Journals (Sweden)

    Saeid Nikafshar

    2017-02-01

    Full Text Available Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM imaging. Additionally, the glass transition temperatures (Tg before and during UV radiation were measured. After an 800 h UV radiation, mechanical test results revealed that the lack of the UV absorber can lead to a ~30% reduction in tensile strength. However, in the presence of Tinuvin 1130, the tensile strength was reduced only by ~11%. It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light.

  9. Some resistance mechanisms to ultraviolet radiation

    International Nuclear Information System (INIS)

    Alcantara D, D.

    2002-12-01

    The cyclical exposure of bacterial cells to the ultraviolet light (UV) it has as consequence an increment in the resistance to the lethal effects of this type of radiation, increment that happens as a result of a selection process of favorable genetic mutations induced by the same UV light. With object to study the reproducibility of the genetic changes and the associate mechanisms to the resistance to UV in the bacteria Escherichia coli, was irradiated cyclically with UV light five different derived cultures of a single clone, being obtained five stumps with different resistance grades. The genetic mapping Hfr revealed that so much the mutation events like of selection that took place during the adaptation to the UV irradiation, happened of random manner, that is to say, each one of the resistant stumps it is the result of the unspecified selection of mutations arisen at random in different genes related with the repair and duplication of the DNA. (Author)

  10. UV imaging in pharmaceutical analysis

    DEFF Research Database (Denmark)

    Østergaard, Jesper

    2018-01-01

    UV imaging provides spatially and temporally resolved absorbance measurements, which are highly useful in pharmaceutical analysis. Commercial UV imaging instrumentation was originally developed as a detector for separation sciences, but the main use is in the area of in vitro dissolution...

  11. A 2.5-dimensional viscous, resistive, advective magnetized accretion-outflow coupling in black hole systems: a higher order polynomial approximation

    Science.gov (United States)

    Ghosh, Shubhrangshu

    2017-09-01

    The correlated and coupled dynamics of accretion and outflow around black holes (BHs) are essentially governed by the fundamental laws of conservation as outflow extracts matter, momentum and energy from the accretion region. Here we analyze a robust form of 2.5-dimensional viscous, resistive, advective magnetized accretion-outflow coupling in BH systems. We solve the complete set of coupled MHD conservation equations self-consistently, through invoking a generalized polynomial expansion in two dimensions. We perform a critical analysis of the accretion-outflow region and provide a complete quasi-analytical family of solutions for advective flows. We obtain the physically plausible outflow solutions at high turbulent viscosity parameter α (≳ 0.3), and at a reduced scale-height, as magnetic stresses compress or squeeze the flow region. We found that the value of the large-scale poloidal magnetic field B P is enhanced with the increase of the geometrical thickness of the accretion flow. On the other hand, differential magnetic torque (-{r}2{\\bar{B}}\\varphi {\\bar{B}}z) increases with the increase in \\dot{M}. {\\bar{B}}{{P}}, -{r}2{\\bar{B}}\\varphi {\\bar{B}}z as well as the plasma beta β P get strongly augmented with the increase in the value of α, enhancing the transport of vertical flux outwards. Our solutions indicate that magnetocentrifugal acceleration plausibly plays a dominant role in effusing out plasma from the radial accretion flow in a moderately advective paradigm which is more centrifugally dominated. However in a strongly advective paradigm it is likely that the thermal pressure gradient would play a more contributory role in the vertical transport of plasma.

  12. The mechanisms of UV mutagenesis

    International Nuclear Information System (INIS)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

    Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: ''error-free'' bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases-the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation. (author)

  13. Deep UV LEDs

    Science.gov (United States)

    Han, Jung; Amano, Hiroshi; Schowalter, Leo

    2014-06-01

    Deep ultraviolet (DUV) photons interact strongly with a broad range of chemical and biological molecules; compact DUV light sources could enable a wide range of applications in chemi/bio-sensing, sterilization, agriculture, and industrial curing. The much shorter wavelength also results in useful characteristics related to optical diffraction (for lithography) and scattering (non-line-of-sight communication). The family of III-N (AlGaInN) compound semiconductors offers a tunable energy gap from infrared to DUV. While InGaN-based blue light emitters have been the primary focus for the obvious application of solid state lighting, there is a growing interest in the development of efficient UV and DUV light-emitting devices. In the past few years we have witnessed an increasing investment from both government and industry sectors to further the state of DUV light-emitting devices. The contributions in Semiconductor Science and Technology 's special issue on DUV devices provide an up-to-date snapshot covering many relevant topics in this field. Given the expected importance of bulk AlN substrate in DUV technology, we are pleased to include a review article by Hartmann et al on the growth of AlN bulk crystal by physical vapour transport. The issue of polarization field within the deep ultraviolet LEDs is examined in the article by Braut et al. Several commercial companies provide useful updates in their development of DUV emitters, including Nichia (Fujioka et al ), Nitride Semiconductors (Muramoto et al ) and Sensor Electronic Technology (Shatalov et al ). We believe these articles will provide an excellent overview of the state of technology. The growth of AlGaN heterostructures by molecular beam epitaxy, in contrast to the common organo-metallic vapour phase epitaxy, is discussed by Ivanov et al. Since hexagonal boron nitride (BN) has received much attention as both a UV and a two-dimensional electronic material, we believe it serves readers well to include the

  14. Growth, photosynthesis and nitrogen metabolism in soybean varieties after exclusion of the UV-B and UV-A/B components of solar radiation

    Directory of Open Access Journals (Sweden)

    Sanjay Singh Baroniya

    2014-12-01

    Full Text Available A field experiment was conducted to study the impact of the exclusion of the solar UV components on growth, photosynthesis and nitrogen metabolism in soybean (Glycine max varieties PK-472, Pusa-24, JS 71-05, JS-335, NRC-7 and Kalitur. The plants were grown in specially designed UV exclusion chambers wrapped with filters to exclude UV-B or UV-A/B and transmitted all UV. Exclusion of UV significantly enhanced the growth of the aerial parts as well as the growth of the below ground parts in all of the six soybean varieties. Nitrate reductase activity (NRA was significantly reduced, whereas leghemoglobin (Lb content, total soluble protein, net photosynthesis (Pn and α-tocopherol content were enhanced after UV exclusion. The exclusion of solar UV-A/B enhanced all parameters to a larger extent than the exclusion of solar UV-B in four of the six varieties of soybean except for NRC-7 and Kalitur. These two varieties responded more to UV-B exclusion compared to UV-A/B exclusion. A significant inverse correlation between the NRA and the number of nodules per plant was observed. The extent of response in all parameters was greater in PK-472 and JS71-05 than that in Kalitur and JS-335 after UV exclusion. The exclusion of UV augmented the growth of nodules, Lb content and α-tocopherol levels and conferred higher rates of Pn to support better growth of nodules. Control plants (+ UV-A/B seemed to fulfill their N demand through the assimilation of NO3− resulting in lower symbiotic nitrogen fixation and higher NR activity.

  15. UV-NIL replication of microlens arrays on flexible fluoropolymer substrates

    DEFF Research Database (Denmark)

    Jucius, Dalius; Lazauskas, Algirdas; Grigaliūnas, Viktoras

    2018-01-01

    This paper describes application of UV-NIL technique for the fabrication of hexagonal OrmoComp microlens arrays on flexible fluoropolymer substrates having exceptional chemical resistance, stability at elevated temperatures and high transmittance in the UV, visible, and infrared regions...... of the spectrum. Uniform and well-defined patterns of close-packed convex microlenses were formed in OrmoComp layers on H2 plasma treated FEP and ETFE substrates by UV-NIL replication of the metalized and liquid paraffin antiadhesive coated negative OrmoComp replicas of the master mold. UV-NIL replication...

  16. Development and first tests of GEM-like detectors with resistive electrodes

    CERN Document Server

    Peskov, Vladimir; Centro, Sandro; Di Mauro, A; Lund-Jensen, B; Martinengo, P; Nappi, E; Oliveira, R; Pietropaolo, F; Picchi, P; Periale, L; Rodionov, I; Ventura, Sandro

    2007-01-01

    We have developed and tested several prototypes of GEM-like detectors with electrodes coated with resistive layers or completely made of resistive materials. These detectors can operate stably at gains close to 105. The resistive layers limit the energy of discharges appearing at higher gains thus making the detectors very robust. We demonstrated that the cathodes of some of these detectors could be coated by CsI or SbCs layers to enhance the detection efficiency for the UV and visible photons. We also discovered that such detectors can operate stably in the cascade mode and high overall gains ($~10^{6}$) are reachable. Applications in several areas, for example in RICH or in noble liquid TPCs are therefore possible. The first results from the detection of UV photons at room and cryogenic temperatures will be given.

  17. Simulation and comparative study on the oxidation kinetics of atrazine by UV/H₂O₂, UV/HSO₅⁻ and UV/S₂O₈²⁻.

    Science.gov (United States)

    Luo, Congwei; Ma, Jun; Jiang, Jin; Liu, Yongze; Song, Yang; Yang, Yi; Guan, Yinghong; Wu, Daoji

    2015-09-01

    This study comparatively investigated atrazine (ATZ) degradation by irradiation at the wavelength of 254 nm in the presence of peroxides including hydrogen peroxide (H2O2), peroxymonosulfate (HSO5(-)), and persulfate (S2O8(2-)) at various initial ATZ concentrations and oxidant dosages. The effects of water matrix, such as carbonate/bicarbonate (HCO3(-)/CO3(2-)), chloride ions (Cl(-)), and natural organic matter (NOM), were evaluated on these three advanced oxidation processes. A simple steady-state kinetic model was developed based on the initial rates of ATZ destruction, which could well describe the apparent pseudo-first-order rate constants (k(app), s(-1)) of ATZ degradation in these three processes. The specific roles of reactive species (i.e., HO·, SO4(-·), CO3(-·), and Cl2(-·)) under various experimental conditions were quantitatively evaluated based on their steady-state concentrations obtained from this model. Modeling results showed that the steady-state concentrations of HO· and SO4(-·) decreased with the increase of CO3(2-)/HCO3(-) concentration, and the relative contribution of HO· to ATZ degradation significantly decreased in UV/H2O2 and UV/HSO5(-) systems. On the other hand, the scavenging effect of HCO3(-)/CO3(2-) on the relative contribution of SO4(-·) to ATZ degradation was lower than that on HO·. The presence of Cl(-) (0.5-10 mM) significantly scavenged SO4(-·) but had slightly scavenging effect on HO· at the present experimental pH, resulting in greater decrease of k(app) in the UV/S2O8(2-) than UV/H2O2 and UV/HSO5(-) systems. Higher levels of Cl2(-·) were generated in the UV/S2O8(2-) than those in the UV/H2O2 and UV/HSO5(-) systems at the same Cl(-) concentrations. NOM significantly decreased k(app) due to its effects of competitive UV absorption and radical scavenging with the latter one being dominant. These results improve the understanding of the effects of water constituents for ATZ degradation in the UV-based oxidation

  18. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  19. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Leer en Español: El ... Aug. 28, 2014 Keep an Eye on Ultraviolet (UV) Safety Eye medical doctors (ophthalmologists) caution us that ...

  20. UV-induced skin damage

    International Nuclear Information System (INIS)

    Ichihashi, M.; Ueda, M.; Budiyanto, A.; Bito, T.; Oka, M.; Fukunaga, M.; Tsuru, K.; Horikawa, T.

    2003-01-01

    Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies suggest that solar UV radiation is responsible for skin tumor development via gene mutations and immunosuppression, and possibly for photoaging. In this review, recent understanding of DNA damage caused by direct UV radiation and by indirect stress via reactive oxygen species (ROS) and DNA repair mechanisms, particularly nucleotide excision repair of human cells, are discussed. In addition, mutations induced by solar UV radiation in p53, ras and patched genes of non-melanoma skin cancer cells, and the role of ROS as both a promoter in UV-carcinogenesis and an inducer of UV-apoptosis, are described based primarily on the findings reported during the last decade. Furthermore, the effect of UV on immunological reaction in the skin is discussed. Finally, possible prevention of UV-induced skin cancer by feeding or topical use of antioxidants, such as polyphenols, vitamin C, and vitamin E, is discussed

  1. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    Aoki, Shigeji; Ito, Shoko; Watanabe, Takehiko

    1979-01-01

    The inactivation by ultraviolet (UV) light irradiation of mycoplasma cells of five human strains was monitored by investigating the colony-forming ability. The survival curves of five strains tested indicated that the cells of Mycoplasma buccale only are single and homogenously susceptible to UV light. The effect of the repair inhibitor, caffeine, on the colony-forming ability of UV-irradiated cells was investigated with M. buccale because of its homogeneous susceptibility to UV light. The colony formation of irradiated cells was markedly depressed by post-irradiation treatment with caffeine at concentration that had little or no effect on the colony formation of unirradiated cells. The colony-forming units (CFU) of UV-irradiated cells which were kept in broth without caffeine in the dark increased without a lag as the time in the dark increased. The colony-forming ability of the irradiated cells completely recovered after 3 hr in the dark. However, when irradiated cells were kept in the presence of caffeine, no increase in their CFU was observed. The mode of action of caffeine on UV-irradiated cells closely resembles that described for other organisms which possess dark reactivation systems for UV-induced damage in deoxyribonucleic acid. Thus, the results obtained provide evidence for the existence of a dark repair function in M. buccale. (author)

  2. Corrosion prevention of iron with novel organic inhibitor of hydroxamic acid and UV irradiation

    International Nuclear Information System (INIS)

    Deng Huihua; Nanjo, Hiroshi; Qian, Pu; Xia Zhengbin; Ishikawa, Ikuo; Suzuki, Toshishige M.

    2008-01-01

    Corrosion prevention by self-assembled monolayers (SAM) of monomer and polymer inhibitor on iron covered with air-formed oxide films was investigated by cyclic voltammetry in borate buffer solution. Anti-corrosion efficiency of the SAM-coated Fe electrodes depends on UV irradiation duration on Fe electrodes prior to coating and inhibitor concentration to form SAM. The 1-h UV-irradiated Fe electrodes coated with SAM exhibits the most effective corrosion resistance despite the anti-corrosion efficiency of air-formed films on Fe was linearly increased with UV irradiation. The addition of monomer in polymer solution improves the stability and corrosion resistance of SAM

  3. Evaluation of Combined Peracetic acid and UV treatment for ...

    Science.gov (United States)

    The current study evaluates the effectiveness of the combined application of Peracetic acid and ultraviolet radiation as alternative disinfectant agents to the traditional chlorination of wastewater effluents. Various pathogens (E. coli, enterococci and fecal coliforms) were evaluated in the study. Four experiments were conducted using low to high PAA levels and UV dosages. E. coli and enterococci were resistant to low to moderate PAA dosage (0.5- 1 mg/L). These microbes can be removed effectively at high PAA dosage (2.5 mg/L) with 30 min contact time. Fecal coliforms were completely inactivated even at a low PAA dose of 0.7 mg/L. E. coli was more susceptible to UV disinfection than enterococci at low UV dosages. Enterococci required at least 40 mJ/cm2 for 2.5 log inactivation. In combined PAA + UV treatment, low UV intensities between 7 – 40 mJ/cm2 showed poor disinfection performance at a low PAA concentration of 1.5 mg/L. High UV intensities of 120 and 60 mJ/cm2 inactivated all the pathogens to below detection levels even at low to moderate PAA (0.7 mg/L and 1 mg/L) pretreatment concentration. Combined PAA + UV treatment at 1 mg/L (for 15 and 30 min contact time) + 120 and 60 mJ/cm2 did not show any regrowth of microbes, whereas PAA only disinfection with 15 min contact time showed regrowth of enterococci and fecal coliforms. UV only disinfection showed E. coli regrowth. • This pilot scale study was designed for providing necessary parameter optimization

  4. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  5. Repair and mutagenesis of herpes simplex virus in UV-irradiated monkey cells

    International Nuclear Information System (INIS)

    Lytle, C.D.; Goddard, J.G.; Lin, C.H.

    1980-01-01

    Mutagenic repair in mammalian cells was investigated by determining the mutagenesis of UV-irradiated or unirradiated herpes simplex virus in UV-irradiated CV-1 monkey kidney cells. These results were compared with the results for UV-enhanced virus reactivation (UVER) in the same experimental situation. High and low multiplicities of infection were used to determine the effects of multiplicity reactivation (MR). UVER and MR were readily demonstrable and were approximately equal in amount in an infectious center assay. For this study, a forward-mutation assay was developed to detect virus mutants resistant to iododeoxycytidine (ICdR), probably an indication of the mutant virus being defective at its thymidine kinase locus. ICdR-resistant mutants did not have a growth advantage over wild-type virus in irradiated or unirradiated cells. Thus, higher fractions of mutant virus indicated greater mutagenesis during virus repair and/or replication. The data showed that: (1) unirradiated virus was mutated in unirradiated cells, providing a background level of mutagenesis; (2) unirradiated virus was mutated about 40% more in irradiated cells, indicating that virus replication (DNA synthesis) became more mutagenic as a result of cell irradiation; (3) irradiated virus was mutated much more (about 6-fold) than unirradiated virus, even in unirradiated cells; (4) cell irradiation did not change the mutagenesis of irradiated virus except at high multiplicity of infection. High multiplicity of infection did not demonstrate UVER or MR alone to be either error-free or error-prone. When the two processes were present simultaneously, they were mutagenic. (orig.)

  6. Selection in vitro for UV-tolerant sugar beet (Beta vulgaris) somaclones

    International Nuclear Information System (INIS)

    Levall, M.W.; Bornman, J.F.

    1993-01-01

    With a reduced stratospheric ozone concentration, the generation of UV-tolerant plants may be of particular importance. Among different crop plants there is large variation in sensitivity to UV-B radiation. This study was undertaken to investigate the possibilities of using somaclonal variation and selection in vitro for improving UV-B tolerance in sugar beet (Beta vulgaris L.). Sugar beet callus was exposed to UV radiation (280–320 nm, 0.863–5.28 kJ m -2 day -1 , unweighted) and resultant shoots were selected from surviving cells. After establishment of the plants, they were grown under either visible radiation (114 μmol m -2 s -1 PAR) or with the addition of UV radiation (6.3 kJ m -2 day -1 biologically effective UV-B). Screening of regenerants in vivo for tolerance to UV radiation was undertaken 10 months after termination of the UV selection pressure. Screening was done visually and by using a number of physiological parameters, including chlorophyll fluorescence induction, ultraweak luminescence, pigment analysis and total content of UV-screening pigments. A clear difference between the unselected and the UV-selected somaclones was observed when visually studying the UV damage and other leaf injury. The observations were supported by the ultraweak luminescence measurements. Unselected plants showed significantly greater damage when subjected to subsequent UV radiation as compared to the selected plants. The clones subjected to UV selection pressure displayed a significantly higher concentration of UV-screening pigments under subsequent UV radiation. The unselected plants under subsequent UV treatment showed a lower carotenoid concentration when compared to selected plants. However, no significant difference between treatments was found for chlorophyll a/b, or F/Fmax, a measure of photosynthetic quantum yield

  7. DNA repair in gamma-and UV-irradiated Escherichia coli treated with caffeine and acriflavine

    International Nuclear Information System (INIS)

    Zhestyanikov, V.D.; Savel'eva, G.E.

    1978-01-01

    A study is made of the postradiation effect of caffeine and acriflavine on the survival rate and DNA repair in E. coli exposed to γ- and UV-radiation. When added to postradiation growth medium caffeine and acriflavine lower the survival rate of γ-irradiated radioresistant strains, B/r and Bsub(s-1)γR, and UV-irradiated UV-resistant strain B/r, and do not appreciably influence the survival of strains that are sensitive to γ- and UV-radiation. The survival rate of UV-irradiated mutant BsUb(s-1) somewhat increases in the presence of caffeine. Caffeine and acriflavine inhibit repair of single-stranded DNA breaks induced in strain B/r by γ-radiation (slow repair) and UV light. Acriflavine arrests a recombination branch of postreplication repair of DNA in E. coli Bsub(s-1)γR Whereas caffeine does not influence this process

  8. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    Energy Technology Data Exchange (ETDEWEB)

    Albert, K.R.; Ro-Poulsen, H. (Univ. of Copenhagen, Dept. of Terrestrial Ecology, Copenhagen (DK)); Mikkelsen, T.N. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Biosystems Dept., Roskilde (DK))

    2008-06-15

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B. (au)

  9. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum.

    Science.gov (United States)

    Albert, Kristian R; Mikkelsen, Teis N; Ro-Poulsen, Helge

    2008-06-01

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B.

  10. Comparative Resistance of Bacterial Foodborne Pathogens to Non-thermal Technologies for Food Preservation.

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

    In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEFs), high hydrostatic pressure (HHP), and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni) would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could also be

  11. Comparative Resistance of Bacterial Foodborne Pathogens to Non-thermal Technologies for Food Preservation

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

    In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEFs), high hydrostatic pressure (HHP), and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni) would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could also be

  12. COMPARATIVE RESISTANCE OF BACTERIAL FOODBORNE PATHOGENS TO NON-THERMAL TECHNOLOGIES FOR FOOD PRESERVATION

    Directory of Open Access Journals (Sweden)

    Guillermo eCebrián

    2016-05-01

    Full Text Available In this paper the resistance of bacterial foodborne pathogens to manosonication (MS, pulsed electric fields (PEF, high hydrostatic pressure (HHP and UV-light (UV is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could

  13. UV/EB curable psa's

    International Nuclear Information System (INIS)

    Glotfelter, C.A.

    1995-01-01

    The author describe both water-based and 100% solids UV/EB curable PSA's (Pressure Sensitive Adhesives) and their properties. A new acrylate monomer, ethoxylated nonyl phenol acrylate, has great utility in the formulation of water-based PSA's

  14. Studies of aluminium nitride ceramics for application in UV dosimetry

    DEFF Research Database (Denmark)

    Trinkler, L.; Bøtter-Jensen, L.; Christensen, P.

    2000-01-01

    The study is reported of the ceramic material AlN-Y2O3 as a potential luminescence dosemeter for the detection of UV radiation. Both the thermoluminescence and the optically stimulated luminescence properties of the material have been studied after exposure to UV radiation and compared with those...... of the widely used dosemeter material Al2O3:C. It has been shown that AlN-Y2O3 ceramics exhibit three orders of magnitude higher sensitivity to UV radiation than does Al2O3,:C over a broad spectral region. The thermoluminescence from AlN-Y2O3 is characterised by linear dose dependence over a wide range....... The fading characteristics of the UV-induced thermoluminescence and optically stimulated luminescence signals with storage time at room temperature were found to be a drawback, but still lower than those induced after exposure to ionising radiation....

  15. UV filters bioaccumulation in fish from Iberian river basins

    Energy Technology Data Exchange (ETDEWEB)

    Gago-Ferrero, Pablo [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens (Greece); Díaz-Cruz, M. Silvia, E-mail: sdcqam@cid.csic.es [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Barceló, Damià [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, C/ Emili Grahit, 101 Edifici H2O, E-17003 Girona (Spain)

    2015-06-15

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/g d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/g d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04–0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. - Highlights: • First evidence of UV filters in fish from Iberian rivers • Biota-sediment accumulation factors (BSAFs) were always below 1. • Predator species presented higher UV-F concentrations suggesting trophic magnification.

  16. UV filters bioaccumulation in fish from Iberian river basins

    International Nuclear Information System (INIS)

    Gago-Ferrero, Pablo; Díaz-Cruz, M. Silvia; Barceló, Damià

    2015-01-01

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/g d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/g d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04–0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. - Highlights: • First evidence of UV filters in fish from Iberian rivers • Biota-sediment accumulation factors (BSAFs) were always below 1. • Predator species presented higher UV-F concentrations suggesting trophic magnification

  17. UV-induced N2O emission from plants

    Science.gov (United States)

    Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

    2014-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  18. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND, B.M.

    2001-07-26

    Organisms living on the earth are exposed to solar radiation, including its ultraviolet (UV) components (for general reviews, the reader is referred to Smith [1] and Young et al. [2]). UV wavelength regions present in sunlight are frequently designated as UVB (290-320 nm) and UVA (320-400 nm). In today's solar spectrum, UVA is the principal UV component, with UVB present at much lower levels. Ozone depletion will increase the levels of UVB reaching the biosphere, but the levels of UVA will not be changed significantly [3]. Because of the high efficiency of UVB in producing damage in biological organisms in the laboratory experiments, it has sometimes been assumed that UVA has little or no adverse biological effects. However, accumulating data [4, 5], including action spectra (efficiency of biological damage as a function of wavelength of radiation; see Section 5) for DNA damage in alfalfa seedlings [6], in human skin [7], and for a variety of plant damages (Caldwell, this volume) indicate that UVA can induce damage in DNA in higher organisms. Thus, understanding the differential effects of UVA and UVB wavebands is essential for estimating the biological consequences of stratospheric ozone depletion.

  19. Sequential and Simultaneous Applications of UV and Chlorine for Adenovirus Inactivation.

    Science.gov (United States)

    Rattanakul, Surapong; Oguma, Kumiko; Takizawa, Satoshi

    2015-09-01

    Adenoviruses are water-borne human pathogens with high resistance to UV disinfection. Combination of UV treatment and chlorination could be an effective approach to deal with adenoviruses. In this study, human adenovirus 5 (HAdV-5) was challenged in a bench-scale experiment by separate applications of UV or chlorine and by combined applications of UV and chlorine in either a sequential or simultaneous manner. The treated samples were then propagated in human lung carcinoma epithelial cells to quantify the log inactivation of HAdV-5. When the processes were separate, a fluence of 100 mJ/cm(2) and a CT value of 0.02 mg min/L were required to achieve 2 log inactivation of HAdV-5 by UV disinfection and chlorination, respectively. Interestingly, synergistic effects on the HAdV-5 inactivation rates were found in the sequential process of chlorine followed by UV (Cl2-UV) (p simultaneous application of UV/Cl2. This implies that a pretreatment with chlorine may increase the sensitivity of the virus to the subsequent UV disinfection. In conclusion, this study suggests that the combined application of UV and chlorine could be an effective measure against adenoviruses as a multi-barrier approach in water disinfection.

  20. UV-Heat Treatments for the Control of Foodborne Microbial Pathogens in Chicken Broth

    Directory of Open Access Journals (Sweden)

    M. Gouma

    2015-01-01

    Full Text Available This investigation established the process criteria for using UV-C light and mild heat (UV-H treatment to inactivate 5-Log10 cycles (performance criterion of common foodborne pathogen populations, Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, when inoculated in chicken broth. To define the target microorganism and the proper UV-H treatment conditions (including UV dose, treatment time, and temperature that would achieve the stated performance criterion, mathematical equations based on Geeraerd’s model were developed for each microorganism. For the sake of comparison, inactivation equations for heat treatments were also performed on the same chicken broth and for the same microorganisms. L. monocytogenes was the most UV-H resistant microorganism at all temperatures, requiring a UV dose between 6.10 J/mL (5.6 min and 2.26 J/mL (2.09 min to achieve 5-Log10 reductions. In comparison with UV treatments at room temperatures, the combination of UV and mild heat allowed both the UV dose and treatment time to be reduced by 30% and 63% at 55°C and 60°C, respectively. Compared to heat treatments, the UV-H process reduced the heating time for 5-Log10 reductions of all the investigated microorganisms in chicken broth from 20-fold to 2-fold when the operating temperature varied from 53 to 60°C.

  1. Higher Education

    African Journals Online (AJOL)

    Kunle Amuwo: Higher Education Transformation: A Paradigm Shilt in South Africa? ... ty of such skills, especially at the middle management levels within the higher ... istics and virtues of differentiation and diversity. .... may be forced to close shop for lack of capacity to attract ..... necessarily lead to racial and gender equity,.

  2. Comments on a Method to Measure Sucralose Using UV Photodegradation Followed by UV Spectrophotometry.

    Science.gov (United States)

    Fang, Te; Andrews, Susan A; Hofmann, Ron

    2017-05-01

    A simple and quick method to measure sucralose in aqueous solution at concentrations in the order of 0.1-1.2 g·L-1 proposed by Idris et al. uses UV irradiation prior to UV spectrophotometry. The photolysis of sucralose forms a photoactive compound characterized by maximum absorbance at approximately 270 nm. The conditions required for sucralose photolysis, however, had not been completely reported. In this work, the procedure described by Idris et al. was replicated using a low-pressure UV lamp to irradiate sucralose samples with a wider range of initial concentrations (0.04-10 g·L-1) with known fluences. It was determined that care must be taken to ensure that the same fluence is applied for both calibration and measurement steps because the absorbance of the sucralose photolysis product is a function of the applied fluence. The way the samples are irradiated also has an impact on the results in that the method exhibits a greater linear range if an apparatus is used that maximizes the fluence rate (e.g., by placing samples closer to the UV source or using a higher-intensity lamp).

  3. Frequency of intrachromosomal homologous recombination induced by UV radiation in normally repairing and excision repair-deficient human cells

    International Nuclear Information System (INIS)

    Tsujimura, T.; Maher, V.M.; McCormick, J.J.; Godwin, A.R.; Liskay, R.M.

    1990-01-01

    To investigate the role of DNA damage and nucleotide excision repair in intrachromosomal homologous recombination, a plasmid containing duplicated copies of the gene coding for hygromycin resistance was introduced into the genome of a repair-proficient human cell line, KMST-6, and two repair-deficient lines, XP2OS(SV) from xeroderma pigmentosum complementation group A and XP2YO(SV) from complementation group F. Neither hygromycin-resistance gene codes for a functional enzyme because each contains an insertion/deletion mutation at a unique site, but recombination between the two defective genes can yield hygromycin-resistant cells. The rates of spontaneous recombination in normal and xeroderma pigmentosum cell strains containing the recombination substrate were found to be similar. The frequency of UV-induced recombination was determined for three of these cell strains. At low doses, the group A cell strain and the group F cell strain showed a significant increase in frequency of recombinants. The repair-proficient cell strain required 10-to 20-fold higher doses of UV to exhibit comparable increases in frequency of recombinants. These results suggest that unexcised DNA damage, rather than the excision repair process per se, stimulates such recombination

  4. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2008-01-01

    ). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower...... during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis...... on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B....

  5. Resistant Hypertension.

    Science.gov (United States)

    Doroszko, Adrian; Janus, Agnieszka; Szahidewicz-Krupska, Ewa; Mazur, Grzegorz; Derkacz, Arkadiusz

    2016-01-01

    Resistant hypertension is a severe medical condition which is estimated to appear in 9-18% of hypertensive patients. Due to higher cardiovascular risk, this disorder requires special diagnosis and treatment. The heterogeneous etiology, risk factors and comorbidities of resistant hypertension stand in need of sophisticated evaluation to confirm the diagnosis and select the best therapeutic options, which should consider lifestyle modifications as well as pharmacological and interventional treatment. After having excluded pseudohypertension, inappropriate blood pressure measurement and control as well as the white coat effect, suspicion of resistant hypertension requires an analysis of drugs which the hypertensive patient is treated with. According to one definition - ineffective treatment with 3 or more antihypertensive drugs including diuretics makes it possible to diagnose resistant hypertension. A multidrug therapy including angiotensin - converting enzyme inhibitors, angiotensin II receptor blockers, beta blockers, diuretics, long-acting calcium channel blockers and mineralocorticoid receptor antagonists has been demonstrated to be effective in resistant hypertension treatment. Nevertheless, optional, innovative therapies, e.g. a renal denervation or baroreflex activation, may create a novel pathway of blood pressure lowering procedures. The right diagnosis of this disease needs to eliminate the secondary causes of resistant hypertension e.g. obstructive sleep apnea, atherosclerosis and renal or hormonal disorders. This paper briefly summarizes the identification of the causes of resistant hypertension and therapeutic strategies, which may contribute to the proper diagnosis and an improvement of the long term management of resistant hypertension.

  6. Benomyl-resistant mutant strain of Trichoderma sp. with increased mycoparasitic activity.

    Science.gov (United States)

    Olejníková, P; Ondrusová, Z; Krystofová, S; Hudecová, D

    2010-01-01

    Application of UV radiation to the strain Trichoderma sp. T-bt (isolated from lignite) resulted in the T-brm mutant which was resistant to the systemic fungicide benomyl. The tub2 gene sequence in the T-brm mutant differed from the parent as well as the collection strain (replacing tyrosine with histidine in the TUB2 protein). Under in vitro conditions this mutant exhibited a higher mycoparasitic activity toward phytopathogenic fungi.

  7. DNA damage caused by UV- and near UV-irradiation

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1986-01-01

    Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

  8. Exclusion of solar UV radiation improves photosynthetic performance and yield of wheat varieties.

    Science.gov (United States)

    Kataria, Sunita; Guruprasad, K N

    2015-12-01

    Field studies were conducted to determine the potential for alterations in photosynthetic performance and grain yield of four wheat (Triticum aestivum) varieties of India- Vidisha, Purna, Swarna and Naveen Chandausi by ambient ultraviolet radiation (UV). The plants were grown in specially designed UV exclusion chambers, wrapped with filters that excluded UV-B (solar UV exclusion increased the leaf mass per area ratio, leaf weight ratio and chlorophylls per unit area of flag leaves in all the four varieties of wheat. Polyphasic chlorophyll a fluorescence transients from the flag leaves of UV excluded wheat plants gave a higher fluorescence yield. Exclusion of solar UV significantly enhanced photosynthetic performance as a consequence of increased efficiency of PS II, performance index (PIABS) and rate of photosynthesis in the flag leaves of wheat varieties along with a remarkable increase in carbonic anhydrase, Rubisco and nitrate reductase activities. This additional fixation of carbon and nitrogen by exclusion of UV was channelized towards the improvement in grain yield of wheat varieties as there was a decrease in the UV-B absorbing substances and an increase in soluble protein content in flag leaves of all the four varieties of wheat. The magnitude of response for UV exclusion for all the measured parameters was higher in two varieties of wheat Vidisha and Purna as compared to Swarna and Naveen Chandausi. Cumulative stress response index (CSRI) for each variety was developed from the cumulative sum of physiological and yield parameters such as leaf mass area ratio of flag leaf, total chlorophyll content, performance index at absorption basis, rate of photosynthesis and grain yield. All the varieties had a negative CSRI, demonstrating a negative impact of ambient UV radiation. Naveen Chandausi and Swarna are less sensitive to ambient UV radiation; Vidisha is more sensitive to both UV-A and UV-B and Purna is more sensitive to ambient UV-B radiation. Copyright

  9. Higher Education

    Science.gov (United States)

    & Development (LDRD) National Security Education Center (NSEC) Office of Science Programs Richard P Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Scholarships STEM Education Programs Teachers (K-12) Students (K-12) Higher Education Regional Education

  10. Two-components UV-therapy

    International Nuclear Information System (INIS)

    Pullmann, H.; Steigleder, G.K.

    1980-01-01

    20 patients with generalized psoriasis were treated with an apparatus containing UV-A- and UV-B-fluorescence tubes to be switched separately. The therapy was started with an UV-A-dose of 12 J/cm 2 daily. After the first week of treatment UV-B in increasing doses was applicated additionally. Clearance was achieved in 80 percent. (orig.) [de

  11. Double transfer UV-curing nanoimprint lithography

    International Nuclear Information System (INIS)

    Shen, Yiming; Yao, Lei; Li, Zhiwei; Kou, Junlong; Cui, Yushuang; Bian, Jie; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng; Li, Wen-Di; Wu, Wei

    2013-01-01

    A challenge in the fabrication of nanostructures into non-planar substrates is to form a thin, uniform resist film on non-planar surfaces. This is critical to the fabrication of nanostructures via a lithographic technique due to the subsequent pattern transfer process. Here we report a new double transfer UV-curing nanoimprint technique that can create a nanopatterned thin film with a uniform residual layer not only on flat substrates but also on highly curved surfaces. Surface relief gratings with pitches down to 200 nm are successfully imprinted on the cylindrical surface of optical fibers, and further transferred into a SiO 2 matrix using reactive ion etching (RIE), demonstrating that our technique is applicable for fabricating high-resolution nanostructures on non-planar substrates. (paper)

  12. Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

    Science.gov (United States)

    Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

    2017-12-01

    Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, Kira S.; Omelchenko, Marina V.; Gaidamakova, Elena K.; Matrosova, Vera Y.; Vasilenko, Alexander; Zhai, Min; Lapidus, Alla; Copeland, Alex; Kim, Edwin; Land, Miriam; Mavrommatis, Konstantinos; Pitluck, Samuel; Richardson, Paul M.; Detter, Chris; Brettin, Thomas; Saunders, Elizabeth; Lai, Barry; Ravel, Bruce; Kemner, Kenneth M.; Wolf, Yuri I.; Sorokin, Alexander; Gerasimova, Anna V.; Gelfand, Mikhail S.; Fredrickson, James K.; Koonin, Eugene V.; Daly, Michael J.

    2007-07-24

    Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at itsoptimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and contribute to

  14. UV light and urban pollution: Bad cocktail for mosquitoes?

    International Nuclear Information System (INIS)

    Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud’homme, Sophie M.; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane

    2014-01-01

    Highlights: •Mosquito tolerance to temephos is induced by PAHs and UV exposure. •Toxicity of fluoranthene for mosquito Malpighian tubules cells is induced by UV. •Fluoranthene crystallizes in mosquito Malpighian tubules upon UV exposure. •Mixture of two PAHs is less toxic for mosquitoes than each PAHs separately. •Combination of abiotic parameters (PAHs and UV) affect mosquito physiology. -- Abstract: Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species–ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis–Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on

  15. UV light and urban pollution: Bad cocktail for mosquitoes?

    Energy Technology Data Exchange (ETDEWEB)

    Tetreau, Guillaume, E-mail: guillaume.tetreau@gmail.com [Laboratoire d’Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09 (France); Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456 (United States); Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud’homme, Sophie M.; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane [Laboratoire d’Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09 (France)

    2014-01-15

    Highlights: •Mosquito tolerance to temephos is induced by PAHs and UV exposure. •Toxicity of fluoranthene for mosquito Malpighian tubules cells is induced by UV. •Fluoranthene crystallizes in mosquito Malpighian tubules upon UV exposure. •Mixture of two PAHs is less toxic for mosquitoes than each PAHs separately. •Combination of abiotic parameters (PAHs and UV) affect mosquito physiology. -- Abstract: Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species–ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis–Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on

  16. Simultaneous energy generation and UV quencher removal from landfill leachate using a microbial fuel cell.

    Science.gov (United States)

    Iskander, Syeed Md; Novak, John T; Brazil, Brian; He, Zhen

    2017-11-01

    The presence of UV quenching compounds in landfill leachate can negatively affect UV disinfection in a wastewater treatment plant when leachate is co-treated. Herein, a microbial fuel cell (MFC) was investigated to remove UV quenchers from a landfill leachate with simultaneous bioelectricity generation. The key operating parameters including hydraulic retention time (HRT), anolyte recirculation rate, and external resistance were systematically studied to maximize energy recovery and UV absorbance reduction. It was found that nearly 50% UV absorbance was reduced under a condition of HRT 40 days, continuous anolyte recirculation, and 10 Ω external resistance. Further analysis showed a total reduction of organics by 75.3%, including the reduction of humic acids, fulvic acids, and hydrophilic fraction concentration as TOC. The MFC consumed 0.056 kWh m -3 by its pump system for recirculation and oxygen supply. A reduced HRT of 20 days with periodical anode recirculation (1 hour in every 24 hours) and 39 Ω external resistance (equal to the internal resistance of the MFC) resulted in the highest net energy of 0.123 kWh m -3 . Granular activated carbon (GAC) was used as an effective post-treatment step and could achieve 89.1% UV absorbance reduction with 40 g L -1 . The combined MFC and GAC treatment could reduce 92.9% of the UV absorbance and remove 89.7% of the UV quenchers. The results of this study would encourage further exploration of using MFCs as an energy-efficient method for removing UV quenchers from landfill leachate.

  17. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    Mehnert, R.

    1999-01-01

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

  18. Acclimation to UV-B radiation and visible light in Lactuca sativa involves up-regulation of photosynthetic performance and orchestration of metabolome-wide responses.

    Science.gov (United States)

    Wargent, J J; Nelson, B C W; McGhie, T K; Barnes, P W

    2015-05-01

    UV-B radiation is often viewed as a source of stress for higher plants. In particular, photosynthetic function has been described as a common target for UV-B impairment; yet as our understanding of UV-B photomorphogenesis increases, there are opportunities to expand the emerging paradigm of regulatory UV response. Lactuca sativa is an important dietary crop species and is often subjected to rapid sunlight exposure at field transfer. Acclimation to UV-B and visible light conditions in L. sativa was dissected using gas exchange and chlorophyll fluorescence measurements, in addition to non-destructive assessments of UV epidermal shielding (SUV ). After UV-B treatment, seedlings were subjected to wide-range metabolomic analysis using liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS). During the acclimation period, net photosynthetic rate increased in UV-treated plants, epidermal UV shielding increased in both subsets of plants transferred to the acclimatory conditions (UV+/UV- plants) and Fv /Fm declined slightly in UV+/UV- plants. Metabolomic analysis revealed that a key group of secondary compounds was up-regulated by higher light conditions, yet several of these compounds were elevated further by UV-B radiation. In conclusion, acclimation to UV-B radiation involves co-protection from the effects of visible light, and responses to UV-B radiation at a photosynthetic level may not be consistently viewed as damaging to plant development. © 2014 John Wiley & Sons Ltd.

  19. Insulin Resistance and Prediabetes

    Science.gov (United States)

    ... Your Baby is Born Monogenic Diabetes Insulin Resistance & Prediabetes Insulin resistance and prediabetes occur when your body ... will stay in the healthy range. What is prediabetes? Prediabetes means your blood glucose levels are higher ...

  20. Parameters for control of an UV-irradiation plant for the disinfection of waste water

    International Nuclear Information System (INIS)

    Rudolph, K.U.; Boettcher, J.; Nelle, T.

    1994-01-01

    A pilot-study with a small UV irradiation unit was done on different wastewater treatment plants to investigate the influence of UV-transmittance, turbidity and flow rate. The on-line measurement of these parameters with the parallel microbiological analysis shows the expected increase of total coliform-concentrations with higher turbidity or lower transmittance. Using the measurement of flow rate, transmittance and turbidity for controling of full-scale UV-plants the operation costs can be decreased. (orig.) [de

  1. A simple way to an ultra-robust superhydrophobic fabric with mechanical stability, UV durability, and UV shielding property.

    Science.gov (United States)

    Ren, Guina; Song, Yuanming; Li, Xiangming; Wang, Bo; Zhou, Yanli; Wang, Yuyan; Ge, Bo; Zhu, Xiaotao

    2018-07-15

    Development of an ultra-robust superhydrophobic fabric with mechanical stability, UV durability, and UV shielding by a simple method is highly desirable, yet it remains a challenge that current technologies have been unable to fully address. Herein, the original fabric is immersed into the solution containing ZnO nanoparticle and PDMS (polydimethylsiloxane), and the fiber surfaces are uniformly covered by a ZnO-PDMS layer after thermal treatment at 110 °C for 30 min. Droplets of water and corrosive liquids including strong acid, strong alkali, and saturated salt solution display sphere shape on the ZnO-PDMS coated fabric surface. The stable binding of ZnO-PDMS layer onto the fibers allows for the fabric coating with robust superhydrophobicity, and the coated fabric still displays superhydrophobicity after hand twisting, knife scratching, finger touching, and even cycles of sandpaper abrasion. The ZnO-PDMS coated fabric can also keep its superhydrophobic property when exposed to long term UV illumination, demonstrating its UV resistance. Moreover, the uniformly distribution of ZnO nanoparticles on fibers allows the ZnO-PDMS coated fabric to display UV shielding property. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Sensitivity of Vibrio cholerae cells to lethal and mutagenic effect of UV-irradiation mediated by plasmids

    International Nuclear Information System (INIS)

    Tiganova, I.G.; Evdokimova, N.M.; Aleshkin, G.I.

    1988-01-01

    The effect of UV-irradiation on Vibrio cholerae cells and its changes mediated by the plasmid R245 have been studied. Vibrio cholerae strains 569B and RV31 have been shown to be considerably more sensitive to lethal effect of UV-irradiation as compared with Escherichia coli and Salmonella typhimurium cells. Highly toxigenic strain 569B and practically atoxigenic strain RV31 have the same UV-sensitivity. Lethla effect of UV-irradiation on Vibrio cholerae cells is incresed when the irradiated cells are plated on enriched media. UV-induction of mutations was not registered in plasmidless strains of Vibrio cholerae. Plasmid R245 increase UV-resistance of vibrio cells and makes them UV-mutable

  3. Comparison Study On Sunlight Or Gamma Radiation Aging Resistance Of Poly (Vinyl Pyrrolidone) Aqueous Solution With PVP Nanogel

    International Nuclear Information System (INIS)

    Doan Binh; Pham Thu Hong; Nguyen Nguyet Dieu; Nguyen Thanh Duoc

    2011-01-01

    Comparison study on sunlight or gamma-radiation aging resistance of poly (vinyl pyrrolidone) (PVP) aqueous solution with PVP nanogel at 0.5% was carried out. Sunlight or gamma- radiation aging resistance of PVP aqueous solution and nanogel was evaluated on the basis of their intrinsic viscosity, UV-VIS absorbance, weight averaged molecular weight (M w ). The PVP aqueous solution and nanogel exposed to sunlight in the storage duration of 3 months and to gamma radiation at absorbed doses of 0, 15, 30, 50 kGy were used for this study. Furthermore, the stability of PVP nanogel and of PVP aqueous solution was also studied on the change of their intrinsic viscosity, UV-VIS absorbance, weight averaged molecular weight, particle size distribution and coil size. The experimental results were shown that the aging resistance of PVP nanogel was higher than that of PVP aqueous solution when exposed to gamma radiation or sunlight. (author)

  4. Higher Education.

    Science.gov (United States)

    Hendrickson, Robert M.

    This chapter reports 1982 cases involving aspects of higher education. Interesting cases noted dealt with the federal government's authority to regulate state employees' retirement and raised the questions of whether Title IX covers employment, whether financial aid makes a college a program under Title IX, and whether sex segregated mortality…

  5. UV-curable polyurethane coatings derived from cellulose

    International Nuclear Information System (INIS)

    Patel, M. M.; Patel, K. I.; Patel, H. B.; Parmar, J. S.

    2009-01-01

    At the present time coating industry is devoting much research in the direction of low volatile organic compounds to make eco-friendly coating material. In this study, such materials are developed from cellulose derived from bagasse, a sugar industry waste. Cellulose is converted to cellulose glyco glycoside by acid hydrolysis of cellulose under heterogeneous condition. Cellulose glyco glycoside is treated with polyethylene glycol having different molecular weights to give glyco glycosides which in turn are reacted with various diisocyanates to obtain polyurethane having free NCO groups. These materials are then reacted with hydroxyethylmethacrylate to give polyurethane acrylates. The acrylates are characterized for specific gravity, viscosity, colour and molecular weight as well as by fourier transform infrared spectroscopy. The UV-curable coating composition was prepared by blending PU-acrylate, reactive diluents and photoinitiator. Coating compositions were cured under UV-light and characterized for adhesion, flexibility, impact resistance, solvent resistance and for dynamic mechanical analysis as well as by thermal gravimetric analysis for thermal stability. The cured films give thickness of 23-24 microns and cure time required is less than 1.5-2.0 min. There is no liberation of any volatiles during curing and films have good adhesion to mild steel substrate. The cured coatings give excellent dynamic, mechanical and chemical properties. The scratch resistance was found to be satisfactory. The application was made in unpigmented form but it is found that various pigments can be used to give coloured UV-curable coatings.

  6. Footprints of the Sun: Memory of UV and Light Stress in Plants

    Directory of Open Access Journals (Sweden)

    Ralf eMüller-Xing

    2014-09-01

    Full Text Available Sunlight provides the necessary energy for plant growth via photosynthesis but high light and particular its integral ultraviolet (UV part causes stress potentially leading to serious damage to DNA, proteins and other cellular components. Plants show adaptation to environmental stresses, sometimes referred to as plant memory. There is growing evidence that plants memorize exposure to biotic or abiotic stresses by epigenetic mechanisms at the cellular level. UV target genes such as CHALCONE SYNTHASE (CHS response immediately to UV treatment and studies of the recently identified UV-B receptor UV RESISTANCE LOCUS 8 (UVR8 confirm the expedite nature of UV signalling. Considering these findings, an UV memory seems redundant. However, several lines of evidence suggest that plants may develop an epigenetic memory of UV and light stress, but in comparison to other abiotic stresses there has been relatively little investigation. Here we summarize the state of knowledge about acclimation and adaptation of plants to UV light and discuss the possibility of chromatin based epigenetic memory.

  7. A comparative study of disinfection efficiency and regrowth control of microorganism in secondary wastewater effluent using UV, ozone, and ionizing irradiation process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, O-Mi [Quarantine Technology Center, Animal and Plant Quarantine Agency Plant, 175 Anyangro, Manan-Gu, Anyang-Si, Gyeonggi-Do 480-757 (Korea, Republic of); Kim, Hyun Young; Park, Wooshin; Kim, Tae-Hun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Yu, Seungho, E-mail: seunghoyu68@gmail.com [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup, Jeonbuk 580-185 (Korea, Republic of)

    2015-09-15

    Highlights: • The ionizing radiation was applied to inactivate microorganisms and the critical dose to prevent the regrowth was determined. • The seasonal variation of disinfection efficiency observed in on-site UV treatment system was influenced by suspended solid, temperature, and precipitation, whereas, stable values were observed in ionizing radiation. • The electrical power consumption for disinfection using UV and ozone requires higher energy than ionizing radiation. - Abstract: Ionizing radiation technology was suggested as an alternative method to disinfection processes, such as chlorine, UV, and ozone. Although many studies have demonstrated the effectiveness of irradiation technology for microbial disinfection, there has been a lack of information on comparison studies of disinfection techniques and a regrowth of each treatment. In the present study, an ionizing radiation was investigated to inactivate microorganisms and to determine the critical dose to prevent the regrowth. As a result, it was observed that the disinfection efficiency using ionizing radiation was not affected by the seasonal changes of wastewater characteristics, such as temperature and turbidity. In terms of bacterial regrowth after disinfection, the ionizing radiation showed a significant resistance of regrowth, whereas, on-site UV treatment is influenced by the suspended solid, temperature, or precipitation. The electric power consumption was also compared for the economic feasibility of each technique at a given value of disinfection efficiency of 90% (1-log), showing 0.12, 36.80, and 96.53 Wh/(L/day) for ionizing radiation, ozone, and UV, respectively. The ionizing radiation requires two or three orders of magnitude lower power consumption than UV and ozone. Consequently, ionizing radiation can be applied as an effective and economical alternative technique to other conventional disinfection processes.

  8. A comparative study of disinfection efficiency and regrowth control of microorganism in secondary wastewater effluent using UV, ozone, and ionizing irradiation process

    International Nuclear Information System (INIS)

    Lee, O-Mi; Kim, Hyun Young; Park, Wooshin; Kim, Tae-Hun; Yu, Seungho

    2015-01-01

    Highlights: • The ionizing radiation was applied to inactivate microorganisms and the critical dose to prevent the regrowth was determined. • The seasonal variation of disinfection efficiency observed in on-site UV treatment system was influenced by suspended solid, temperature, and precipitation, whereas, stable values were observed in ionizing radiation. • The electrical power consumption for disinfection using UV and ozone requires higher energy than ionizing radiation. - Abstract: Ionizing radiation technology was suggested as an alternative method to disinfection processes, such as chlorine, UV, and ozone. Although many studies have demonstrated the effectiveness of irradiation technology for microbial disinfection, there has been a lack of information on comparison studies of disinfection techniques and a regrowth of each treatment. In the present study, an ionizing radiation was investigated to inactivate microorganisms and to determine the critical dose to prevent the regrowth. As a result, it was observed that the disinfection efficiency using ionizing radiation was not affected by the seasonal changes of wastewater characteristics, such as temperature and turbidity. In terms of bacterial regrowth after disinfection, the ionizing radiation showed a significant resistance of regrowth, whereas, on-site UV treatment is influenced by the suspended solid, temperature, or precipitation. The electric power consumption was also compared for the economic feasibility of each technique at a given value of disinfection efficiency of 90% (1-log), showing 0.12, 36.80, and 96.53 Wh/(L/day) for ionizing radiation, ozone, and UV, respectively. The ionizing radiation requires two or three orders of magnitude lower power consumption than UV and ozone. Consequently, ionizing radiation can be applied as an effective and economical alternative technique to other conventional disinfection processes

  9. Women With Gestational Diabetes Mellitus Randomized to a Higher-Complex Carbohydrate/Low-Fat Diet Manifest Lower Adipose Tissue Insulin Resistance, Inflammation, Glucose, and Free Fatty Acids: A Pilot Study.

    Science.gov (United States)

    Hernandez, Teri L; Van Pelt, Rachael E; Anderson, Molly A; Reece, Melanie S; Reynolds, Regina M; de la Houssaye, Becky A; Heerwagen, Margaret; Donahoo, William T; Daniels, Linda J; Chartier-Logan, Catherine; Janssen, Rachel C; Friedman, Jacob E; Barbour, Linda A

    2016-01-01

    Diet therapy in gestational diabetes mellitus (GDM) has focused on carbohydrate restriction but is poorly substantiated. In this pilot randomized clinical trial, we challenged the conventional low-carbohydrate/higher-fat (LC/CONV) diet, hypothesizing that a higher-complex carbohydrate/lower-fat (CHOICE) diet would improve maternal insulin resistance (IR), adipose tissue (AT) lipolysis, and infant adiposity. At 31 weeks, 12 diet-controlled overweight/obese women with GDM were randomized to an isocaloric LC/CONV (40% carbohydrate/45% fat/15% protein; n = 6) or CHOICE (60%/25%/15%; n = 6) diet. All meals were provided. AT was biopsied at 37 weeks. After ∼7 weeks, fasting glucose (P = 0.03) and free fatty acids (P = 0.06) decreased on CHOICE, whereas fasting glucose increased on LC/CONV (P = 0.03). Insulin suppression of AT lipolysis was improved on CHOICE versus LC/CONV (56 vs. 31%, P = 0.005), consistent with improved IR. AT expression of multiple proinflammatory genes was lower on CHOICE (P vs. 12.6 ± 2%, respectively). A CHOICE diet may improve maternal IR and infant adiposity, challenging recommendations for a LC/CONV diet. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  10. The role of UV-B radiation in aquatic and terrestrial ecosystems - an experimental and functional analysis of the evolution of UV-absorbing componist.

    NARCIS (Netherlands)

    Rozema, J.; Bjorn, L.O.; Bornman, J.F.; Gaberscik, A.; Hader, D.P.; Trost, T.; Germ, M.; Klisch, M.; Groniger, A.; Sinha, R.P.; Lebert, M.; He, Y.Y.; Buffoni-Hall, R.; Bakker, N.; van de Staaij, J.W.M.; Meijkamp, B.B.

    2002-01-01

    We analysed and compared the functioning of UV-B screening pigments in plants from marine, fresh water and terrestrial ecosystems, along the evolutionary line of cyanobacteria, unicellular algae, primitive multicellular algae, charophycean algae, lichens, mosses and higher plants, including

  11. Assessment of DNA damage and repair in Mycobacterium terrae after exposure to UV irradiation.

    Science.gov (United States)

    Bohrerova, Z; Linden, K G

    2006-11-01

    Ultraviolet (UV) irradiation for drinking water treatment was examined for inactivation and subsequent dark and photo-repair of Mycobacterium terrae. UV sources tested were low pressure (monochromatic, 254 nm) and medium pressure (polychromatic UV output) Hg lamps. UV exposure resulted in inactivation, and was followed by dark or photo-repair experiments. Inactivation and repair were quantified utilizing a molecular-based endonuclease sensitive site (ESS) assay and conventional colony forming unit (CFU) viability assay. Mycobacterium terrae was more resistant to UV disinfection compared to many other bacteria, with approximately 2-log reduction at a UV fluence of 10 mJ cm(-2) ; similar to UV inactivation of M. tuberculosis. There was no difference in inactivation between monochromatic or polychromatic UV lamps. Mycobacterium terrae did not undergo detectable dark repair. Photo-repair resulted in recovery from inactivation by approximately 0.5-log in less than 30 min for both UV lamp systems. Mycobacterium terrae is able to photo-repair DNA damage within a short timeframe. The number of pyrimidine dimers induced by UV light were similar for Escherichia coli and M. terrae, however, this similarity did not hold true for viability results. There is no practical difference between UV sources for disinfection or prevention of DNA repair for M. terrae. The capability of M. terrae to photo-repair UV damage fairly quickly is important for wastewater treatment applications where disinfected effluent is exposed to sunlight. Finally, molecular based assay results should be evaluated with respect to differences in the nucleic acid content of the test micro-organism.

  12. Distinct UV-B and UV-A/blue light signal transduction pathways induce chalcone synthase gene expression in Arabidopsis cells

    International Nuclear Information System (INIS)

    Christie, J.M.; Jenkins, G.I.

    1996-01-01

    UV and blue light control the expression of flavonoid biosynthesis genes in a range of higher plants. To investigate the signal transduction processes involved in the induction of chalcone synthase (CHS) gene expression by UV-B and UV-A/blue light, we examined the, effects of specific agonists and inhibitors of known signaling components in mammalian systems in a photomixotrophic Arabidopsis cell suspension culture. CHS expression is induced specifically by these wavelengths in the cell culture, in a manner similar to that in mature Arabidopsis leaf tissue. Both the UV-B and UV-A/blue phototransduction processes involve calcium, although the elevation of cytosolic calcium is insufficient on its own to stimulate CHS expression. The UV-A/blue light induction of CHS expression does not appear to involve calmodulin, whereas the UV-B response does; this difference indicates that the signal transduction pathways are, at least in part, distinct. We provide evidence that both pathways involve reversible protein phosphorylation and require protein synthesis. The UV-B and UV-A/blue light signaling pathways are therefore different from the phytochrome signal transduction pathway regulating CHS expression in other species

  13. Removal of Emerging Contaminants and Estrogenic Activity from Wastewater Treatment Plant Effluent with UV/Chlorine and UV/H₂O₂ Advanced Oxidation Treatment at Pilot Scale.

    Science.gov (United States)

    Rott, Eduard; Kuch, Bertram; Lange, Claudia; Richter, Philipp; Kugele, Amélie; Minke, Ralf

    2018-05-07

    Effluent of a municipal wastewater treatment plant (WWTP) was treated on-site with the UV/chlorine (UV/HOCl) advanced oxidation process (AOP) using a pilot plant equipped with a medium pressure UV lamp with an adjustable performance of up to 1 kW. Results obtained from parallel experiments with the same pilot plant, where the state of the art UV/H₂O₂ AOP was applied, were compared regarding the removal of emerging contaminants (EC) and the formation of adsorbable organohalogens (AOX). Furthermore, the total estrogenic activity was measured in samples treated with the UV/chlorine AOP. At an energy consumption of 0.4 kWh/m³ (0.4 kW, 1 m³/h) and in a range of oxidant concentrations from 1 to 6 mg/L, the UV/chlorine AOP had a significantly higher EC removal yield than the UV/H₂O₂ AOP. With free available chlorine concentrations (FAC) in the UV chamber influent of at least 5 mg/L (11 mg/L of dosed Cl₂), the total estrogenic activity could be reduced by at least 97%. To achieve a certain concentration of FAC in the UV chamber influent, double to triple the amount of dosed Cl₂ was needed, resulting in AOX concentrations of up to 520 µg/L.

  14. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  15. The UV-B Photoreceptor UVR8: From Structure to Physiology

    Science.gov (United States)

    Jenkins, Gareth I.

    2014-01-01

    Low doses of UV-B light (280 to 315 nm) elicit photomorphogenic responses in plants that modify biochemical composition, photosynthetic competence, morphogenesis, and defense. UV RESISTANCE LOCUS8 (UVR8) mediates photomorphogenic responses to UV-B by regulating transcription of a set of target genes. UVR8 differs from other known photoreceptors in that it uses specific Trp amino acids instead of a prosthetic chromophore for light absorption during UV-B photoreception. Absorption of UV-B dissociates the UVR8 dimer into monomers, initiating signal transduction through interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1. However, much remains to be learned about the physiological role of UVR8 and its interaction with other signaling pathways, the molecular mechanism of UVR8 photoreception, how the UVR8 protein initiates signaling, how it is regulated, and how UVR8 regulates transcription of its target genes. PMID:24481075

  16. Near UV Aerosol Group Report

    Science.gov (United States)

    Torres, Omar

    2013-01-01

    2012-13 Report of research on aerosol and cloud remote sensing using UV observations. The document was presented at the 2013 AEROCENTER Annual Meeting held at the GSFC Visitors Center, May 31, 2013. The Organizers of the meeting are posting the talks to the public Aerocentr website, after the meeting.

  17. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

  18. Effects of prolonged UV-B exposure in plants

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... effects of UV radiation on plants and other organisms. .... competitive interactions may also be altered indirectly by ..... lesions show a high degree of evolutionary conservation ... period between anther dehiscence pollination, and there- .... ultraviolet climate and the ecological consequences for higher ...

  19. UV-Curing of Nanoparticle Reinforced Acrylates

    International Nuclear Information System (INIS)

    Bauer, F.

    2006-01-01

    Polymer reinforcement by silica and alumina nanoparticles evidently yields improved surface hardness. Single mixing of nanoparticles into an acrylate formulations, however, leads to highly viscous solutions inappropriate for coating procedures. The incompatibility of inorganic fillers and organic polymers can be avoided by surface modification providing an interface between the two dissimilar materials. For example, vinyltrimethoxysilane (VTMO) can react via hydrolysis/condensation reactions with hydroxyl groups present on the inorganic surface and should bond via the polymerisation-active vinyl group to an acrylate resin through crosslinking reactions. Grafting reactions of surface OH groups and different trialkoxysilanes were studied by thermogravimetry, infrared, and multinuclear NMR spectroscopy. The copolymeri-zation of modified nanoparticles with the acrylate matrix has been investigated by 13 C NMR spectroscopy. UV curing under nitrogen inertization revealed a lower reactivity of vinyl groups of VTMO-modified silica compared to grafted methacryloxypropyl-trimethoxysilane (MEMO) which showed complete conversion of olefinic carbons (signals at 120 - 140 ppm). Under conditions of oxygen inhibition, the effect of the kind and the concentration of photoinitiator on the photopoly-merization reaction was studied. Compared to neat polyacrylate coatings the nanocomposite materials exhibit markedly improved properties, e.g., heat, scratch, and abrasion resistance. However, a much better abrasion resistance was obtained for coatings containing both silica nano-particles and corundum microparticles. In particular cases, radiation curing with 172 nm photons generated by Xe excimer was performed to obtain structured polymer surfaces, i.e., matting of the reinforced acrylate coatings

  20. UV light and urban pollution: bad cocktail for mosquitoes?

    Science.gov (United States)

    Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane

    2014-01-01

    Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species-ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis-Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further

  1. Production and accumulation of UV-B [ultra violet] absorbing compounds in UV-B irradiated leaves of rice, Oryza SativaL.: effects of varying UV-B doses on leaf damage, phenolic content and HPLC [high performance liquid chromatography] peak I area

    International Nuclear Information System (INIS)

    Caasi-Lit, M.T.

    2005-01-01

    The effects of varying UV-B doses on leaf damage, phenolic content and HPLC peak 1 area were studied using 65-d-old plants of the UV-B tolerant rice cultivar, M202, and the UV-B susceptible rice cultivar, Dular. Results showed that the production and accumulation of UV-B- absorbing compounds in rice leaves were affected by leaf position and levels (dose) of UV-B and time or duration of UV-B irradiation or exposure. The youngest terminal leaves showed the least damage when exposed to medium and high UV-B doses. The production of these absorptive compounds as represented by relative phenolic and HPLC peak 1 were significantly higher in younger leaves and lower in older or senescing leaves. M202 showed significantly higher amounts of peak 1 area and relative phenolic compared to UV-B susceptible rice cultivar, Dular. The results also confirmed the strong relationship of overall damage rating and area of HPLC peak 1. The development of UV-B symptoms in the susceptible cultivar was hastened when a high UV-B treatment was applied. Peak 1 area did not accumulate in the UV-B susceptible Dular at any given UV-B dose

  2. [Microwave assisted UV electrodeless discharge lamp photochemical degradation of 4-chlorophenol in aquatic solutions].

    Science.gov (United States)

    Ai, Zhi-hui; Jiang, Jun-qing; Yang, Peng; Zhou, Tao; Lu, Xiao-hua

    2004-07-01

    A microwave assisted UV electrodeless discharge lamp system (MW/UV) was used for photo-degradation of 4CP simulated wastewater. In order to evaluate the degradation efficiency of 4CP, UV spectrophotometry and ion chromatography were used for determination of 4CP and Cl- respectively. The degradation rate in MW/UV system was higher than that in the UV system within 120min, which were 52.40% and 21.56% respectively. The degradation efficiency was improved by increasing pH value of the solution, aerating O2 gas, enhancing light intensity, or adding H2O2 oxidant. The degradation of 4CP under MW/UV accords with the first order kinetics equation.

  3. Characterization of antibodies specific for UV-damaged DNA by ELISA

    Energy Technology Data Exchange (ETDEWEB)

    Eggset, G; Volden, G; Krokan, H

    1987-04-01

    The specificity of affinity purified antibodies raised against UV-irradiated DNA was examined using an enzyme-linked immunosorbent assay. DNA irradiated with UV doses higher than needed for saturation with pyrimidine dimers bound increasing amounts of antibody. Photosensitized DNA, containing high amounts of pyrimidine dimers, showed very poor binding of antibody. When UV-irradiated DNA was given a second dose of 340-nm UV light, the binding of antibodies was inhibited. Taken together, this indicates a major specificity for (6-4)-photoproducts, which are photochemically reversed by UV light in the 340-nm region. The antibodies also showed little but detectable binding to pyrimidine glycols produced in DNA by oxidation with OsO/sub 4/. Previously, we have used these antibodies for the detection of UV-induced DNA damage and its repair in human skin in vivo. These findings indicate that (6-4)-photoproducts, considered highly mutagenic, are repaired in human skin.

  4. Characterization of antibodies specific for UV-damaged DNA by ELISA

    International Nuclear Information System (INIS)

    Eggset, G.; Volden, G.; Krokan, H.; Norsk Hydro Research Centre, Porsgrunn

    1987-01-01

    The specificity of affinity purified antibodies raised against UV-irradiated DNA was examined using an enzyme-linked immunosorbent assay. DNA irradiated with UV doses higher than needed for saturation with pyrimidine dimers bound increasing amounts of antibody. Photosensitized DNA, containing high amounts of pyrimidine dimers, showed very poor binding of antibody. When UV-irradiated DNA was given a second dose of 340-nm UV light, the binding of antibodies was inhibited. Taken together, this indicates a major specificity for (6-4)-photoproducts, which are photochemically reversed by UV light in the 340-nm region. The antibodies also showed little but detectable binding to pyrimidine glycols produced in DNA by oxidation with OsO 4 . Previously, we have used these antibodies for the detection of UV-induced DNA damage and its repair in human skin in vivo. These findings indicate that (6-4)-photoproducts, considered highly mutagenic, are repaired in human skin. (author)

  5. Distinct physiological and metabolic reprogramming by highbush blueberry (Vaccinium corymbosum) cultivars revealed during long-term UV-B radiation.

    Science.gov (United States)

    Luengo Escobar, Ana; Alberdi, Miren; Acevedo, Patricio; Machado, Mariana; Nunes-Nesi, Adriano; Inostroza-Blancheteau, Claudio; Reyes-Díaz, Marjorie

    2017-05-01

    Despite the Montreal protocol and the eventual recovery of the ozone layer over Antarctica, there are still concerns about increased levels of ultraviolet-B (UV-B) radiation in the Southern Hemisphere. UV-B induces physiological, biochemical and morphological stress responses in plants, which are species-specific and different even for closely related cultivars. In woody plant species, understanding of long-term mechanisms to cope with UV-B-induced stress is limited. Therefore, a greenhouse UV-B daily course simulation was performed for 21 days with two blueberry cultivars (Legacy and Bluegold) under UV-B BE irradiance doses of 0, 0.07 and 0.19 W m -2 . Morphological changes, photosynthetic performance, antioxidants, lipid peroxidation and metabolic features were evaluated. We found that both cultivars behaved differently under UV-B exposure, with Legacy being a UV-B-resistant cultivar. Interestingly, Legacy used a combined strategy: initially, in the first week of exposure its photoprotective compounds increased, coping with the intake of UV-B radiation (avoidance strategy), and then, increasing its antioxidant capacity. These strategies proved to be UV-B radiation dose dependent. The avoidance strategy is triggered early under high UV-B radiation in Legacy. Moreover, the rapid metabolic reprogramming capacity of this cultivar, in contrast to Bluegold, seems to be the most relevant contribution to its UV-B stress-coping strategy. © 2016 Scandinavian Plant Physiology Society.

  6. Induction of mutations in blue-green alga Anacystis nidulans by consolidated and split UV irradiation

    International Nuclear Information System (INIS)

    Amla, D.V.

    1979-01-01

    Ultraviolet mutability of consolidated and split dose treatment in A. nidulans was investigated with reference to induction of phage- and streptomycin-resistant markers. The consolidated UV treatment induced both the markers about 100-150-fold, whereas under photoreactivating conditions the survival of alga was enhanced and mutation frequency was decreased. The split UV treatment with 6 hr dark incubation between two UV exposures enhanced the survival and mutation frequencies to 500-700 fold above the back-ground level. The data give indirect evidence for the presence of error-prone dark repair system in this organism. (auth.)

  7. CVD diamond sensor for UV-photon detection

    CERN Document Server

    Periale, L; Gervino, G; Lamarina, A M; Palmisano, C; Periale, R; Picchi, P

    2012-01-01

    A new generation of UV photosensors, based on single crystal Chemical Vapour Deposition (CVD) diamonds to work optically coupled with large volume two-phase liquid-Ar (LAr) or liquid-Xe (LXe) detectors nowadays under design for the next generation of WIMPs experiments, is under development. Preliminary tests and first calibrations show these devices can have better performance than the existing UV sensitive detectors (higher photosensitivity and better signal-to-noise ratio). I-V characteristics, dark current measurements, linearity response to X-ray irradiation, and alpha-particle energy resolution are reported and discussed. (C) 2011 Elsevier B.V. All rights reserved.

  8. Changes in UV absorption of sunscreens after UV irradiation

    Science.gov (United States)

    Tarras-Wahlberg, N.; Stenhagen, G.; Larkö, O.; Rosén, A.; Wennberg, A.-M.; Wennerström, O.

    2000-03-01

    In the present investigation we have studied the change in the absorption spectrum of some photoactive organic species in sunscreens after UVA and UVB irradiation in a dose normally encountered during a full day in the sun. The absorbance of 2-ethylhexyl 4-methoxycinnamate was reduced significantly, while 3-(4-methylbenzyliden)camphor seemed to be rather stable. The benzophenones studied seemed to be relatively stable. In the case of 4-tert.butyl-4´-methoxy-dibenzoylmethane there was a rapid decrease in the UVA absorption leading to unsatisfactory protection in the UVA region. 4-Isopropyl-dibenzoylmethane also lost most of its UV protective capacity after irradiation with UVA. UVB seemed to have a minor effect on all the samples. The present study including gas chromatography and mass spectrometry analysis indicates that some of the photoactive organic species commonly used today in sunscreens are unstable following UV irradiation.

  9. UV and vacuum-UV biological spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Ito, Amando Siuiti

    1996-01-01

    Full text. Synchrotron radiation has been used as light source in the UV and VUV region for the study of many biological systems. In the time domain, measurements are made that allow the observation of dynamics and kinetics of biomolecules like proteins and peptides, using the fluorescent properties of either intrinsic or extrinsic probes. Optical activity of groups inside biomolecules allows the use of circular dichroism techniques to generate structural information and to follow processes like protein folding. Confocal scanning of synchrotron light generates microscopy resolution below 100 nm, allowing the creation of high quality three dimensional images of biological samples, and the collection of fluorescence originated from microvolumes inside the samples. We propose a station at LNLS for these three techniques: time-resolved fluorescence, circular dischroism and confocal microscopy, using UV and VUV light. (author)

  10. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    International Nuclear Information System (INIS)

    Stamm, L.V.; Charon, N.W.

    1988-01-01

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species

  11. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, L.V.; Charon, N.W.

    1988-03-01

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species.

  12. Human chromosome 9 can complement UV sensitivity of xeroderma pigmentosum group A cells

    International Nuclear Information System (INIS)

    Ishizaki, Kanji; Sasaki, Masao S.; Ikenaga, Mituo; Nakamura, Yusuke

    1990-01-01

    A single human chromosome derived from normal human fibroblasts and tagged with the G418 resistance gene was transferred into SV40-transformed xeroderma pigmentosum group A (XP-A) cells via microcell fusion. When chromosome 1 or 12 was transferred, UV sensitivity of microcell hybrid cells was not changed. By contrast, after transferring chromosome 9,7 of 11 reipient clones were as UV-resistant as normal human cells. Four other clones were still as UV-sensitive as the parental XP-A cells. Southern hybridization analysis using a polymorphic probe, pEKZ19.3, which is homologous to a sequence of the D9S17 locus on chromosome 9, has confirmed that at least a part of normal human chromosome 9 was transferred into the recipient clones. However, amounts iof UV-induced unscheduled DNA synthesis in the UV-resistant clones were only one-third of those in normal human cells. These results indicate that a gene on chromosome 9 can confer complementation of high UV sensitivity of XP-A cells although it is still possible that 2 or more genes might be involved in the defective-repair phenotypes of XP-A. (author). 20 refs.; 3 figs.; 1 tab

  13. An extended sequence specificity for UV-induced DNA damage.

    Science.gov (United States)

    Chung, Long H; Murray, Vincent

    2018-01-01

    The sequence specificity of UV-induced DNA damage was determined with a higher precision and accuracy than previously reported. UV light induces two major damage adducts: cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6-4)pyrimidone photoproducts (6-4PPs). Employing capillary electrophoresis with laser-induced fluorescence and taking advantages of the distinct properties of the CPDs and 6-4PPs, we studied the sequence specificity of UV-induced DNA damage in a purified DNA sequence using two approaches: end-labelling and a polymerase stop/linear amplification assay. A mitochondrial DNA sequence that contained a random nucleotide composition was employed as the target DNA sequence. With previous methodology, the UV sequence specificity was determined at a dinucleotide or trinucleotide level; however, in this paper, we have extended the UV sequence specificity to a hexanucleotide level. With the end-labelling technique (for 6-4PPs), the consensus sequence was found to be 5'-GCTC*AC (where C* is the breakage site); while with the linear amplification procedure, it was 5'-TCTT*AC. With end-labelling, the dinucleotide frequency of occurrence was highest for 5'-TC*, 5'-TT* and 5'-CC*; whereas it was 5'-TT* for linear amplification. The influence of neighbouring nucleotides on the degree of UV-induced DNA damage was also examined. The core sequences consisted of pyrimidine nucleotides 5'-CTC* and 5'-CTT* while an A at position "1" and C at position "2" enhanced UV-induced DNA damage. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  14. Effect of nutrient supply on photosynthesis and pigmentation to short-term stress (UV radiation) in Gracilaria conferta (Rhodophyta)

    International Nuclear Information System (INIS)

    Figueroa, F.L.; Israel, A.; Neori, A.; Martinez, B.; Malta, E.J.; Put, A.; Inken, S.; Marquardt, R.; Abdala, R.; Korbee, N.

    2010-01-01

    The effects of increased photosynthetic active radiation (PAR), UV radiation (UVR), and nutrient supply on photosynthetic activity, pigment content, C:N ratio and biomass yield were studied in tank cultivated Gracilaria conferta (Rhodophyta). Electron transport rate (ETR) and biliprotein content were higher under high nutrient supply (HNS), obtained from fishpond effluents, compared to low nutrient supply (LNS), in contrast to mycosporine-like amino acids (MAAs) dynamic. The high MAA content in LNS-algae could be explained by higher UVR penetration in the thallus and by the competition for the use of nutrients with other processes. Effective quantum yield decreased after short-term exposure to high irradiance whereas full recovery in shade was produced only under slightly heat shock. UVA radiation provoked an additional decrease in photosynthesis under high water temperature. UVB radiation reversed UVA's negative effect mainly with HNS. Results support that nutrient-sufficiency help G. conferta to resist environmental changes as short-term temperature increase.

  15. UV spectrophotometry of the Metronidazole

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-10-01

    Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

  16. Contribution to Casein Determination by UV Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Stefanescu Raluca

    2017-12-01

    Full Text Available In the present paper, the interaction between copper ions and proteins is presented, in order to elaborate a simple and rapid spectrophotometric assay of casein in milk. Under alkaline conditions, copper ions form the biuret complex with the proteins, which can be used in protein determination. Although very specific, the biuret method is less sensitive. Using insoluble copper phosphate, casein is able to extract copper ions, with which it forms the biuret complex, while either the complex or copper ions could be determined in the ultraviolet range. Indeed, an increased absorbance of biuret complex at 215 nm was found. Nevertheless, copper ions can be determined in UV as well, their concentration being proportional to that of casein. When used tetraglycine instead casein, mass spectrometric measurements at pH higher than 11 revealed the formation of complexes with many copper ions bound to each peptide bond-containing molecule. Nevertheless, on diluting the biuret solution the complex may dissociate leading to very complex UV spectra that should be further studied.

  17. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  18. uvbyHβ photometry of UV-bright stars

    International Nuclear Information System (INIS)

    Wade, B.R.; Smith, L.F.

    1985-01-01

    uvbyHβ photometry is presented for 90 stars taken from an early version of the Carnochan and Wilson catalogue (1983. Mon. Not. R. astr. Soc. 202,317) of stars that have very negative UV colours. Two have definite UV excesses, (HD 36629, and HD81307). Four early-B stars have UV colours too positive for their visible classification, and β-indices that indicate higher luminosities than appear possible on galactic distribution grounds. Six late-B stars appear to have discordant flux distributions for which there are no obvious explanations. It is suggested that the high population of subluminous stars derived by Carnochan and Wilson is the product of the statistical treatment used and the extreme patchiness in the interstellar absorption. (author)

  19. Detection of Fish Bones in Cod Fillets by UV Illumination.

    Science.gov (United States)

    Wang, Sheng; Nian, Rui; Cao, Limin; Sui, Jianxin; Lin, Hong

    2015-07-01

    The presence of fish bones is now regarded as an important hazard in fishery products, and there is increasing demand for new analytical techniques to control it more effectively. Here, the fluorescent properties of cod bones under UV illumination were investigated, and the maximal wavelengths for excitation and emission were determined to be 320 nm and 515 nm, respectively, demonstrating significantly different fluorescence characteristics and much higher fluorescence intensity compared to those of fillet muscles. Based on the results, UV fluorescence-assisted candling for the detection of bones in fishery products was developed for the first time. Using cod fillets as samples, the detection ratio of this technique was calculated as 90.86%, significantly higher than that of traditional candling under daylight (76.78%). Moreover, the working efficiency of the new technique was about 26% higher than that of the traditional method. A UV fluorescence imaging framework was also developed, and a method for automatic identification of the fish bones in the cod fillets based on the linear discriminant analysis proposed by Fisher was preliminarily realized, but the detection ratio was demonstrated to be relatively poor compared to those of candling techniques. These results allow us to suggest UV-based methods as new and promising approaches for routine monitoring of bones in fishery products.

  20. Higher Total Protein Intake and Change in Total Protein Intake Affect Body Composition but Not Metabolic Syndrome Indexes in Middle-Aged Overweight and Obese Adults Who Perform Resistance and Aerobic Exercise for 36 Weeks.

    Science.gov (United States)

    Campbell, Wayne W; Kim, Jung Eun; Amankwaah, Akua F; Gordon, Susannah L; Weinheimer-Haus, Eileen M

    2015-09-01

    Studies assessing the effects of protein supplementation on changes in body composition (BC) and health rarely consider the impact of total protein intake (TPro) or the change in TPro (CTPro) from participants' usual diets. This secondary data analysis assessed the impact of TPro and CTPro on changes in BC and metabolic syndrome (MetS) indexes in overweight and obese middle-aged adults who participated in an exercise training program. Men and women [n = 117; age: 50 ± 0.7 y, body mass index (BMI; in kg/m(2)): 30.1 ± 0.3; means ± SEs] performed resistance exercise 2 d/wk and aerobic exercise 1 d/wk and consumed an unrestricted diet along with 200-kcal supplements (0, 10, 20, or 30 g whey protein) twice daily for 36 wk. Protein intake was assessed via 4-d food records. Multiple linear regression model and stratified analysis were applied for data analyses. Among all subjects, TPro and CTPro were inversely associated (P exercise training, higher TPro promoted positive changes in BC but not in MetS indexes in overweight and obese middle-aged adults. Changes in TPro from before to during the intervention also influenced BC responses and should be considered in future research when different TPro is achieved via diet or supplements. This trial was registered at clinicaltrials.gov as NCT00812409. © 2015 American Society for Nutrition.

  1. Photoreactivation of UV-irradiated blue-green algae and algal virus LPP-1

    Energy Technology Data Exchange (ETDEWEB)

    Singh, P K [Central Rice Research Inst., Cuttack (India)

    1975-01-01

    Ultraviolet (UV) sensitivity and photoreactivation of blue-green algae Cylindrospermum sp., Plectonema boryanum, spores of Fischerella muscicola and algal virus (cyanophage) LPP-1 were studied. The survival value after UV irradiation of filaments of Cylindrospermum sp. and Virus LPP-1 showed exponential trend and these were comparatively sensitive towards UV than F. muscicola and P. boryanum. Photoreactivation of UV-induced damage occurred in black, blue, green, yellow, red and white light in Cylindrospermum sp., however only black, blue and white light were capable of photorepair of UV-induced damage in P. boryanum, spores of F. muscicola and virus LPP-1 in infected host alga. Pre-exposure to yellow and black light did not show photoprotection. The non-heterocystous and nitrogen fixation-less mutants of Cylindrospermum sp. were not induced by UV and their spontaneous mutation frequency was not affected after photoreactivation. The short trichome mutants of P. boryanum were more resistant towards UV. The occurrence of photoreactivation of UV-induced killing in wide range of light in Cylindrospermum sp. is the first report in organisms.

  2. Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer.

    Science.gov (United States)

    Liu, Wei; Dai, Xing; Xie, Jian; Silver, Mark A; Zhang, Duo; Wang, Yanlong; Cai, Yawen; Diwu, Juan; Wang, Jian; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

    2018-02-07

    The accurate detection of UV radiation is required in a wide range of chemical industries and environmental or biological related applications. Conventional methods taking advantage of semiconductor photodetectors suffer from several drawbacks such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. Searching for new strategies or materials serving as precise UV dosage sensor with extremely low detection limit is still highly desirable. In this work, a radiation resistant uranium coordination polymer [UO 2 (L)(DMF)] (L = 5-nitroisophthalic acid, DMF = N,N-dimethylformamide, denoted as compound 1) was successfully synthesized through mild solvothermal method and investigated as a unique UV probe with the detection limit of 2.4 × 10 -7 J. On the basis of the UV dosage dependent luminescence spectra, EPR analysis, single crystal structure investigation, and the DFT calculation, the UV-induced radical quenching mechanism was confirmed. Importantly, the generated radicals are of significant stability which offers the opportunity for measuring the accumulated UV radiation dosage. Furthermore, the powder material of compound 1 was further upgraded into membrane material without loss in luminescence intensity to investigate the real application potentials. To the best of our knowledge, compound 1 represents the most sensitive coordination polymer based UV dosage probe reported to date.

  3. UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report

    International Nuclear Information System (INIS)

    Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

    2012-01-01

    radiation or by sunbed UV lamps. All studies of the project (240 volunteers) were structured concerning UV skin type II and III, age and sex. In addition, data on the natural skin protection of the volunteers against UV radiation were measured in order to evaluate possible correlations between individual UV sensitivity and the efficiency of vitamin D synthesis. In result: In winter time, before starting the studies, the mean 25OH-vitamin D serum level of 18 ng/ml of the volunteers was in the deficiency range (< 20 ng/ml). UV exposures of 10 % MED applied twice a week vertically to face and hands caused significant increases of the 25OH-vitamin D serum level. The increase rised with higher UV doses and/or larger skin area exposed to UV radiation of the solar summer spectrum. While the increase of the 25OHvitamin D serum level in the UV cabinet was roughly independent from the basic level, under solar exposure conditions there were distinct variations between subjects as well as different outcomes for the whole group, which possibly depended on low outdoor temperatures during the solar exposures. Exposures by sunbed UV lamps lead to decreasing efficiencies in vitamin D production. An increase of the biologically effective UV dose and/or of the UV-exposed skin area decreased the vitamin D efficiency down to 30 % compared to simulated solar radiation. Because of strong differences in UV erythema sensitivity of the skin of different anatomical locations, we hypothesized similar relations in the efficiency of UV-induced vitamin D synthesis. The efficiency of UV-induced vitamin D synthesis varies up to 400 % between the anatomical locations of the body. The investigation of the content of provitamin D (7-Dehydrocholesterol), the source of the vitamin D synthesis in the skin, and of the influence of UV exposure on the level of this content results in new findings, too. Suberythemal UV exposures do not influence the 7-DHC-concentration in the skin. 1 MED leads to a significant

  4. Coupling UV irradiation and electrocoagulation for reclamation of urban wastewater

    International Nuclear Information System (INIS)

    Cotillas, Salvador; Llanos, Javier; Miranda, Oscar G.; Díaz-Trujillo, Gerardo C.; Cañizares, Pablo; Rodrigo, Manuel A.

    2014-01-01

    Graphical abstract: - Highlights: • Iron electrodes allow removing turbidity and E. coli in urban wastewaters. • Enmeshment into growing flocs and oxidation are the key disinfection processes. • A synergistic effect of coupling UV and EC is found at low current densities. • Efficiency of UV irradiation is lowered at high current density. - Abstract: This work focuses on coupling electrocoagulation, with iron electrodes, and UV irradiation (photo-electrocoagulation) for the simultaneous removal of turbidity and E. coli from actual treated municipal wastewaters. Results show that single electrocoagulation behaves as a very efficient technology even using low current densities. E. coli is removed not only by the enmeshment of microorganisms into growing flocs, but also by the attack of electrochemically produced chlorine disinfectant species. Coupling UV irradiation to electrocoagulation with iron electrodes improves the process performance in terms of E. coli and turbidity removal. The effect of current density on process performance was evaluated, finding a synergistic interaction of both techniques at low current density (1.44 A m −2 ) but an antagonistic effect at higher values of current density (7.20 A m −2 ). This antagonistic effect is caused by the less efficient transmission of UV irradiation to the bulk solution due to the increase in the concentration of solids

  5. UV Tanning Equipment | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

    Sun lamps and tanning equipment emit ultraviolet (UV) rays. People who are exposed to UV rays over a long period of time are more likely to develop skin cancer. People with light skin are in more danger because their skin is more sensitive to UV rays.

  6. Improved performance of UV-LED by p-AlGaN with graded composition

    KAUST Repository

    Yan, Jianchang

    2010-11-02

    AlGaN-based ultraviolet light emitting diodes (UV-LEDs) on AlN/sapphire template were grown by metal organic chemical vapour deposition. The AlN template was characterized by atomic force microscopy and high resolution X-ray diffraction. Atomic force microscopy image shows that the AlN surface is very flat, while high resolution X-ray diffraction results prove the good crystalline quality of the AlN template. A novel structure UV-LED which has several p-AlGaN layers with graded composition is compared with a common structure UV-LED which has a single p-Al0.5Ga0.5N layer. The forward bias voltage at 20 mA driving current for the novel structure UV-LED is nearly 3 V higher than that of the common structure UV-LED, however, the electroluminescence intensity of the former is over two times higher than that of the latter. The total quantum efficiency of the novel structure UV-LED is more than 50% higher than that of the common structure UV-LED. The improvement is considered to be the result of better holes injection efficiency in the novel structure UV-LED. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mutation induction by ion beams in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-04-01

    This review mainly describes study results obtained in the Takasaki ion-beam (IB) irradiation facility (TIARA) on the mutation induction in higher plants. Biological effects like lethality and on budding of IBs (carbon, Ne and Ar) are discussed in relation with their linear energy transfer (LET), relative biological effectiveness and the developmental states in shepherd's-purse and tobacco. Induced mutation by IB are characterized by those findings that the mutation rate by C beam is 1.9 x 10{sup -6}, being 17 times higher than the electron beam, in the shepherd's-purse, that C beam induces larger structural changes than electron beam when examined by molecular mechanism of tt and gl gene mutations, and that mutation spectrum of IB is different from that of {gamma}-ray and is wider. Novel mutants are described on shepherd's-purse (pigment mutants, ultraviolet (UV)-resistant and sensitive ones, and flowering ones), disease-resistant rice, barley and tobacco plants, and flowering plants. IB mutation is possibly useful for solving the problems of environment and foods in future. (N.I.)

  8. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  9. Soy-based UV resistant polyurethane pultruded composites.

    Science.gov (United States)

    2012-02-01

    Aliphatic polyurethane (PU) nanocomposites were synthesized using organically modified nanoclays. X-Ray diffraction results : confirmed good exfoliation of nanoclay particles in the PU resin system. With the addition of just 1% of nanoclay in the bas...

  10. Variations in constitutive and inducible UV-B tolerance; dissecting photosystem II protection in Arabidopsis thaliana accessions.

    Science.gov (United States)

    Jansen, Marcel A K; Martret, Bénedicte Le; Koornneef, Maarten

    2010-01-01

    The rise in ultraviolet-B (UV-B) (280-315 nm) radiation levels, that is a consequence of stratospheric ozone layer depletion, has triggered extensive research on the effects of UV-B on plants. Plants raised under natural sunlight conditions are generally well protected from the potentially harmful effects of UV-B radiation. However, it is mostly unknown to which extent UV protection is constitutive and/or induced. In this study, we have analysed the role of constitutive and inducible protection responses in avoiding UV-B damage to photosystem II of photosynthesis. We have assayed the UV susceptibility of photosystem II in 224 Arabidopsis thaliana accessions from across the Northern hemisphere, and found a continuum of constitutive UV-protection levels, with some accessions being UV sensitive and others UV tolerant. Statistical analysis showed only very weak associations between constitutive UV tolerance and the geographic origin of accessions. Instead, most of the variance in constitutive UV-B protection of photosynthesis is present at the level of local Arabidopsis populations originating in the same geographic and climatic area. The variance in constitutive UV protection is, however, small compared to the amplitude of environmentally induced changes in UV protection. Thus, our data emphasise the importance of inducible responses for the protection of photosystem II against UV-B. Remarkably, the conditions that induce UV-protective responses vary; accessions from lower latitudes were found to switch-on UV defences more readily than those of higher latitudes. Such altered regulation of induction may comprise a suitable adaptation response when levels of a stressor are fluctuating in the short term, but predictable over longer periods.

  11. miR-296-3p, miR-298-5p and their downstream networks are causally involved in the higher resistance of mammalian pancreatic α cells to cytokine-induced apoptosis as compared to β cells

    Directory of Open Access Journals (Sweden)

    Barbagallo Davide

    2013-01-01

    Full Text Available Abstract Background The molecular bases of mammalian pancreatic α cells higher resistance than β to proinflammatory cytokines are very poorly defined. MicroRNAs are master regulators of cell networks, but only scanty data are available on their transcriptome in these cells and its alterations in diabetes mellitus. Results Through high-throughput real-time PCR, we analyzed the steady state microRNA transcriptome of murine pancreatic α (αTC1-6 and β (βTC1 cells: their comparison demonstrated significant differences. We also characterized the alterations of αTC1-6 cells microRNA transcriptome after treatment with proinflammatory cytokines. We focused our study on two microRNAs, miR-296-3p and miR-298-5p, which were: (1 specifically expressed at steady state in αTC1-6, but not in βTC1 or INS-1 cells; (2 significantly downregulated in αTC1-6 cells after treatment with cytokines in comparison to untreated controls. These microRNAs share more targets than expected by chance and were co-expressed in αTC1-6 during a 6–48 h time course treatment with cytokines. The genes encoding them are physically clustered in the murine and human genome. By exploiting specific microRNA mimics, we demonstrated that experimental upregulation of miR-296-3p and miR-298-5p raised the propensity to apoptosis of transfected and cytokine-treated αTC1-6 cells with respect to αTC1-6 cells, treated with cytokines after transfection with scramble molecules. Both microRNAs control the expression of IGF1Rβ, its downstream targets phospho-IRS-1 and phospho-ERK, and TNFα. Our computational analysis suggests that MAFB (a transcription factor exclusively expressed in pancreatic α cells within adult rodent islets of Langerhans controls the expression of miR-296-3p and miR-298-5p. Conclusions Altogether, high-throughput microRNA profiling, functional analysis with synthetic mimics and molecular characterization of modulated pathways strongly suggest that specific

  12. UV and plasma treatment of thin silver layers and glass surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hluschi, J.H. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Helmke, A. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Roth, P. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Boewer, R. [Interpane Glasbeschichtungsgesellschaft mbH and Co KG, Sohnreystr. 21, D-37697 Lauenfoerde (Germany); Herlitze, L. [Interpane Glasbeschichtungsgesellschaft mbH and Co KG, Sohnreystr. 21, D-37697 Lauenfoerde (Germany); Vioel, W. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany)]. E-mail: vioel@hawk-hhg.de

    2006-11-10

    Thin silver layers can be modified by treatment with UV radiation or a plasma discharge. UV treatment at a wavelength of {lambda}=308 -bar nm improves the layer properties, thus leading to an enhancement of the layers IR reflectivity. For the purpose of in situ-measurement the sheet resistance is recorded during the process. Due to the Hagen-Rubens-Relation [E. Hagen, H. Rubens, Ann. Phys. 11 (1903) 873]-bar the sheet resistance is linked to the IR reflectivity of thin metal-films. A pretreatment of uncoated glass using a dielectric barrier discharge activates and cleans its surface, thus leading to an increase in adhesion of thin layers.

  13. UV and plasma treatment of thin silver layers and glass surfaces

    International Nuclear Information System (INIS)

    Hluschi, J.H.; Helmke, A.; Roth, P.; Boewer, R.; Herlitze, L.; Vioel, W.

    2006-01-01

    Thin silver layers can be modified by treatment with UV radiation or a plasma discharge. UV treatment at a wavelength of λ=308 -bar nm improves the layer properties, thus leading to an enhancement of the layers IR reflectivity. For the purpose of in situ-measurement the sheet resistance is recorded during the process. Due to the Hagen-Rubens-Relation [E. Hagen, H. Rubens, Ann. Phys. 11 (1903) 873]-bar the sheet resistance is linked to the IR reflectivity of thin metal-films. A pretreatment of uncoated glass using a dielectric barrier discharge activates and cleans its surface, thus leading to an increase in adhesion of thin layers

  14. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

  15. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  16. Effect of degradative plasmid CAM-OCT on responses of Pseudomonas bacteria to UV light

    International Nuclear Information System (INIS)

    McBeth, D.L.

    1989-01-01

    The effect of plasmid CAM-OCT on responses to UV irradiation was compared in Pseudomonas aeruginosa, in Pseudomonas putida, and in Pseudomonas putida mutants carrying mutations in UV response genes. CAM-OCT substantially increased both survival and mutagenesis in the two species. P. aeruginosa strains without CAM-OCT exhibited much higher UV sensitivity than did P. putida strains. UV-induced mutagenesis of plasmid-free P. putida was easily detected in three different assays (two reversion assays and one forward mutation assay), whereas UV mutagenesis of P. aeruginosa without CAM-OCT was seen only in the forward mutation assay. These results suggest major differences in DNA repair between the two species and highlight the presence of error-prone repair functions on CAM-OCT. A number of P. putida mutants carrying chromosomal mutations affecting either survival or mutagenesis after UV irradiation were isolated, and the effect of CAM-OCT on these mutants was determined. All mutations producing a UV-sensitive phenotype in P. putida were fully suppressed by the plasmid, whereas the plasmid had a more variable effect on mutagenesis mutations, suppressing some and producing no suppression of others. On the basis of the results reported here and results obtained by others with plasmids carrying UV response genes, it appears that CAM-OCT may differ either in regulation or in the number and functions of UV response genes encoded

  17. Estimation of surface UV levels based on Meteor-3/TOMS ozone data

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, Y A [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I V [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V U [Central Aerological Observatory, Moscow (Russian Federation)

    1996-12-31

    The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

  18. UV-B effects on crops: response of the irrigated rice ecosystem

    International Nuclear Information System (INIS)

    Olszyk, D.; Dai, Q.; Teng, P.; Leung, H.; Luo, Y.; Peng, S.

    1996-01-01

    Increasing ultraviolet-B (UV-B) radiation resulting from depletion of the stratospheric ozone layer could have damaging effects on crops. This paper reviews recent findings on direct effects of UV-B on rice growth and yield as well as indirect effects via impacts on other organisms in the rice (Oryza sativa) agroecosystem. The findings are based on research by scientists at the International Rice Research Institute (IRRI) in Los Baños, the Philippines, and their collaborators in China and the United States; with comparison to research by scientists in other countries. Current results indicate that while enhanced UV-B directly impacts many aspects of rice growth, physiology, and biochemistry under controlled phytotron conditions; in general rice growth and yield are not affected under natural field conditions. The difference in response may be related both to the levels of UV-B exposure used in phytotron vs. field studies and the lower ratio of UV-A to UV-B in the phytotron compared to field. In terms of indirect effects on rice blast disease, enhanced UV-B affected both the fungus itself (Pyricularia grisea) and the susceptibility of the rice plant to the fungus. Based on these data, simulation models estimated potential impacts of higher UV-B levels on blast severity and rice yield in different countries of southeast and east Asia. Ultimately, results from rice studies can be used to identify strategies to minimize any negative effects of UV-B on rice productivity

  19. UV reflectance is associated with environmental conditions in Palaearctic Pieris napi (Lepidoptera: Pieridae).

    Science.gov (United States)

    Stella, David; Pecháček, Pavel; Meyer-Rochow, Victor Benno; Kleisner, Karel

    2018-06-01

    The subject of our investigation was the visual features of wing color with special focus on the UV reflectance in the green-veined white butterfly (Pieris napi). Previous studies had concluded that UV reflectance on dorsal wing surfaces is found only in the female P. napi. Based on UV sensitive photography, we analyzed a correlation between 12 geographic and environmental factors and UV reflectance patterns on 3 patches on the forewings of 407 P. napi specimens from the Palaearctic region. Results had shown that females significantly differ from males: they exhibit a 25% higher UV reflectance. To investigate whether and how UV reflectance levels on the forewings and hindwings of both sexes are influenced by the environment, we performed a principal component analysis (PCA) with several environmental variables. For several variables (in particular, latitude and longitude, mean annual temperature and precipitation, and temperature annual range and altitude), the generalized linear model (GLM) model revealed a significant correlation in both sexes. This suggests a link between UV reflectance levels and the environment and distribution of P. napi. We found that stronger UV reflectance is associated with generally more hostile environments and concluded that large-scale environmental factors influence the UV reflectance on the forewings of both male and female green-veined white butterflies. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  20. Estimation of surface UV levels based on Meteor-3/TOMS ozone data

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, Y.A. [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I.V. [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Moscow (Russian Federation)

    1995-12-31

    The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

  1. Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

    Science.gov (United States)

    Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

    2011-02-01

    A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Direct interaction between verapamil and doxorubicin causes the lack of reversal effect of verapamil on P-glycoprotein mediated resistance to doxorubicin in vitro using L1210/VCR cells

    International Nuclear Information System (INIS)

    Breier, A.; Drobna, Z.; Barancik, M.

    1998-01-01

    Mouse leukemic cell sub-line L 1210/VCR exerts expressive multidrug resistance (MDR) that is mediated by P-glycoprotein. Cells originally adapted to vincristine are also extremely resistant to doxorubicin. Resistance to both vincristine and doxorubicin is connected with depression of drug uptake. While resistance of L 121 O cells to vincristine could be reversed by verapamil as chemo-sensitizer, resistance of cells to doxorubicin was insensitive to verapamil. Action of verapamil (well-known inhibitor of PGP activity) on multidrug resistance was often used as evidence that MDR is mediated by PGP. From this point it may be possible that the resistance of L1210/VCR cells to vincristine is mediated by PGP and the resistance to doxorubicin is mediated by other PGP-independent system. Another and more probable explanation of different effect of verapamil on resistance of L1210/VCR cells to vincristine and doxorubicin may be deduced from the following fact: Using UV spectroscopy we found that doxorubicin dissolved in water buffered medium interacts effectively with verapamil. This interaction may be responsible for the decrease of concentration of both drugs in free effective form and consequently for higher survival of cells. In contrast to doxorubicin vincristine does not give any interaction with verapamil that is measurable by UV spectroscopy and resistance of L1210/VCR cells to vincristine may be fully reversed by verapamil. (authors)

  3. Antiproliferative effects of ZnO, ZnO-MTCP, and ZnO-CuMTCP nanoparticles with safe intensity UV and X-ray irradiation.

    Science.gov (United States)

    Sadjadpour, Susan; Safarian, Shahrokh; Zargar, Seyed Jalal; Sheibani, Nader

    2016-01-01

    In photodynamic therapy (PDT) of cancer both the light and the photosensitizing agent are normally harmless, but in combination they could result in selective tumor killing. Zinc oxide nanoparticles were synthesized and coated with the amino acid cysteine to provide an adequate arm for conjugation with porphyrin photosensitizers (meso-tetra (4-carboxyphenyl) porphyrin [MTCP] and CuMTCP). Porphyrin-conjugated nanoparticles were characterized by TEM, FTIR, and UV-vis, and fluorescence spectrophotometry. The 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability in the presence or absence of porphyrin conjugates following UV and X-ray irradiation. The uptake of the porphyrin-conjugated ZnO nanoparticles by cells was detected using fluorescence microscopy. Our results indicated that the survival of T-47D cells was significantly compromised in the presence of ZnO-MTCP-conjugated nanostructures with UV light exposure. Exhibition of cytotoxic activity of ZnO-MTCP for human prostate cancer (Du145) cells occurred at a higher concentration, indicating the more resistant nature of these tumor cells. ZnO-CuMTCP showed milder cytotoxic effects in human breast cancer (T-47D) and no cytotoxic effects in Du145 with UV light exposure, consistent with its lower cytotoxic potency as well as cellular uptake. Surprisingly, none of the ZnO-porphyrin conjugates exhibited cytotoxic effects with X-ray irradiation, whereas ZnO alone exerted cytotoxicity. Thus, ZnO and ZnO-porphyrin nanoparticles with UV or X-ray irradiation may provide a suitable treatment option for various cancers. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  4. Induction and repair of lethal and oncogenic lesions and their relationship to cytogenetic changes in UV-irradiated mouse 10T1/2 cells

    International Nuclear Information System (INIS)

    Chan, G.L.; Nagasawa, H.; Little, J.B.

    1979-01-01

    While bacterial system is valuable for the pragmatic purpose of screening potential environmental carcinogens, the fundamental difference between prokaryotes and mammalian cells warrant caution against the use of bacterial mutagenic mechanisms to explain the oncogenic process in mammalian cells. The 10 T1/2 cells exposed to UV light in the plateau phase and subcultured immediately to low density to assay for clonogenic survival were extremely resistant to the cytotoxic effect of UV light. Purely physical considerations such as the increased thickness of plateau phase cells and the increased cytoplasmic shielding of UV light from the nuclei were insufficient to account for this unusual resistance. The effect of caffeine on the repair processes in UV-irradiated mammalian cells appears to be exerted during the first DNA synthetic phase after the UV exposure. The daughter DNA synthesized on a UV-irradiated template is of reduced molecular weight. 10 T1/2 cells were exposed in the log phase of growth to UV light, and then they were cultured for the next 48 hours in the complete growth medium containing the specific concentration of caffeine. Parallel experiments were performed, in which cells were exposed for 48 hours to caffeine only with no prior exposure to UV light. It was found that caffeine did not potentiate the transformation by UV light. Caffeine alone induced sister chromatid exchange (SCE), whereas the caffeine given after UV light had no effect. The class of UV-induced lesions which induce SCE also leads to malignant transformation. (Yamashita, S.)

  5. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  6. Surface Coating of Musa Brachycarpa Trunk Using UV-Radiation

    International Nuclear Information System (INIS)

    Danu, Sugiarto; Sumarni, Anik; Nurhadi, Agus; Puspita, Rita

    2000-01-01

    An experiment on UV-curing of surface coating of Musa brachycarpa was carried out using urethane acrylate polymer films. Radiation curable material was the mixture of urethane acrylate resin, tripropylene glycol diacrylate monomer (TPGDA) and radical photo initiator of 2,2-dimethyl -2-hydroxy acetophenone. The TPGDA concentrations in the mixture with urethane acrylate resin were 60; 70 and 80% weight, Whereas concentrations of photo initiator were varied at the level 1.5:2.0 and 2.5% by weight based on resin and monomer mixture. Irradiation was conducted by using 80 Watt/cm intensity UV-light at the conveyor speed of 2: 3 and 4 m/min. Analysis and film properties observed were IR spectrum, gel fraction, hardness, abrasion resistance, glossy and chemical, solvent and stain resistances. Films have good resistances against 1% sodium carbonate, 5% acetic acid, 50% alcohol, thinner and red, blue and black permanent marker, except against 10% sodium hydroxide and 10% sulfuric acid. Optimum condition was achieved at the photo initiator concentration level of 2% and conveyor speed of 3 m/min

  7. Characterization of ultraviolet light-induced diphtheria toxin-resistant mutations in normal and Xeroderma pigmentosum human fibroblasts

    International Nuclear Information System (INIS)

    Glover, T.W.

    1979-01-01

    Quantitative mutagenesis studies in human cells have been severely limited by the lack of reliable genetic markers. Experiments were therefore performed to develop and characterize a better quantitative mutation assay for human cells. The uv-induction of diphtheria toxin resistant (DT/sup r/) mutations in normal and excision repair defective xeroderma pigmentosum (XP) fibroblasts has been quantitatively characterized. A concentration of diphtheria toxin to use in the selection of resistant mutants was determined whereby DT/sup r/ cells are cross-resistant to Pseudomonas aeurginosa exotoxin A, indicating mutants have altered elongation factor-2 (EF-2) which is not susceptible to ADP-ribosylation by either toxin. Results of this study indicate that XP fibroblasts have higher uv-induced mutation frequencies per unit uv-dose but similar frequencies per unit survival compared to normal cells as measured using a new genetic marker for quantitative mutagenesis. Furthermore, these results support a prediction of the mutation theory of cancer, namely, that cells from individuals with certain human syndromes that predispose the individual to cancer will have higher induced mutation frequencies than cells from non-susceptible individuals. This newly characterized genetic marker should be useful in quantitative mutagenesis studies in human cells

  8. Disodium cromoglycate may act as a novel adjuvant for UV-attenuated Toxoplasma gondii vaccine in mouse model.

    Science.gov (United States)

    Li, Xi; Wu, Yifan; Huang, Shiguang; Lu, Fangli

    2018-06-01

    We have proven the beneficial effects during acute Toxoplasma gondii infection when mast cells were inhibited by disodium cromoglycate (DSCG). Here we investigated the adjuvant effect of DSCG on the protective efficacy of UV-attenuated T. gondii (UV-Tg) vaccine. Mice were infected with 10 2 Tg alone or infected with 10 2 Tg plus DSCG (Tg + DSCG), immunized with 10 5 UV-Tg and challenged with 10 2 Tg (UV-Tg + Tg) or immunized with 10 5 UV-Tg plus DSCG and challenged with 10 2 Tg (UV-Tg + DSCG + Tg). Compared to Tg group, Tg + DSCG, UV-Tg + Tg, and UV-Tg + DSCG + Tg showed significantly prolonged survival times, decreased parasite burdens, reduced liver histopathologies, and increased levels of Th1 and Th2 cytokines and IL-17 in the livers and spleens by using quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Compared to UV-Tg + Tg, UV-Tg + DSCG + Tg had significantly longer survival time, lower tissue parasite burden and histopathological score, and higher levels of Th1 and Th2 cytokines and IL-17 in the livers or spleens. Our data suggest that DSCG may play an adjuvant role in the immunization induced by UV-attenuated T. gondii in mice, by promoting cellular immune response against T. gondii challenge. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina (Rhodophyta)

    Science.gov (United States)

    Zhao, Jiqiang; Li, Lixia

    2014-11-01

    Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance. We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) of red algae Grateloupia filicina (Lamour.) C. Agardh. The activities of SOD, CAT, and APX changed in response to UV-B in a time- and dose-dependent manner. POX activity increased significantly under all three UV-B treatments. The enzymatic assay showed three distinct bands of SODI (Mn-SOD), SODII (Fe-SOD), and SODIII (CuZn-SOD) under a low (Luv) and medium (Muv) dose of UV-B irradiation, while SODI and SODIII activities decreased significantly when exposed to a high dose of UV-B irradiation (Huv). The activity of POX isoenzymes increased significantly after exposure to UV-B, which is consistent with the total activity. In addition, a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments. Some bands of APX isoenzyme were also clearly influenced by UV-B irradiation. Correspondingly, the daily growth rate declined under all the three exposure doses, and was especially significant under Muv and Huv treatments. These data suggest that, although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage, G. filicina has incomplete tolerance to higher UV-B irradiation stress.

  10. Medical UV exposures and HIV activation

    International Nuclear Information System (INIS)

    Zmudzka, B.Z.; Miller, S.A.; Jacobs, M.E.; Beer, J.Z.

    1996-01-01

    This paper presents the first attempt to evaluate the potential of clinical UV exposures to induce the human immunodeficiency (HIV) promoter and, thus, to upregulate HIV growth in those skin cells that are directly affected by the exposure. Using the data for HIV promoter activation in vitro, we computed UVB and psoralen plus UVA (PUVA) doses that produce 50% of the maximal promoter activation (AD 50 ). Then, using (a) literature data for UV transmittance in the human skin, (b) a composite action spectrum for HIV promoter and pyrimidine dimer induction by UVB and (c) an action spectrum for DNA synthesis inhibition by PUVA, we estimated the distribution of medical UVB and PUVA doses in the skin. This allowed us to estimate how deep into the skin the HIV-activating doses might penetrate in an initial and an advanced stge of UVB and PUVA therapy. Such analysis was done for normal type II skin and for single exposures. For UVB we found that, when the incident dose on the surface of the skin is 500 J/m 2 (290-320 nm) (initial stage of the therapy), the dose producing 50% of the maximal HIV promoter activation (AD 50 UVB ) is limited to the stratum corneum. For PUVA we found that, when the incident UVA doses are 25 or 100 kJ/m 2 (320-400 nm) (an initial and an advanced stage of therapy, respectively), and the 8-methoxypsoralen concentration in the blood is 0.1 μg/mL (the desired level), the combined doses to the mid epidermis (and some areas of the upper dermis) are well below the 50% HIV promoter-activating PUVA dose (AD 50 PUVA ). These results suggest that the probability of HIV activation in the epidermis by direct mechanisms is higher for UVB than for PUVA treatment. However, complexities of the UV-inducible HIV activation and immunomodulatory phenomena are such that our results by themselves should not be taken as an indication that UVB therapy carries a high risk than PUVA therapy when administered to HIV-infected patients. (Author)

  11. Synthesis and characterization of UV-absorbing fluorine-silicone acrylic resin polymer

    Science.gov (United States)

    Lei, Huibin; He, Deliang; Guo, Yanni; Tang, Yining; Huang, Houqiang

    2018-06-01

    A series of UV-absorbing fluorine-silicone acrylic resin polymers containing different amount of UV-absorbent were successfully prepared by solution polymerization, with 2-[3-(2H-Benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate (BHEM), vinyltrimethoxysilane (VTMS) and hexafluorobutyl methacrylate (HFMA) as modifying monomers. The acrylic polymers and the coatings thereof were characterized by Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) absorption spectrum, thermogravimetric analysis (TGA), water contact angle (CA) and Xenon lamp artificial accelerated aging tests. Results indicated that the resin exhibited high UV absorption performance as well as good thermal stability. The hydrophobicity of the coatings was of great improvement because of the bonded fluorine and silicone. Meanwhile, the weather-resistance was promoted through preferably colligating the protective effects of BHEM, organic fluorine and silicone. Also, a fitting formula about the weatherability with the BMHE content was tentatively proposed.

  12. Biological effects of N+ ion implantation and UV radiation on streptomyces albus

    International Nuclear Information System (INIS)

    Wu Jian; Dai Guifu

    2005-01-01

    The results of both 30 keV N + ion implantation and UV irradiation of Streptomyces albus showed complicate biological effects. The 'saddle shape' pattern of the dose-dependent curve formed by N + ion implantation with low energy was studied, and it proved that vacuum was not the reason, and the fact, the 'saddle shape' curve may be regarded as a HRS/IRR (hyper-radiosensitivity/increased radiaoresistance) effect caused by low dose irradiation. But Streptomyces albus UV irradiated after vacuum treatment only showed IRR effect or hormesis (survival rate >100%). The streptomycin resistance mutation of Streptomyces albus caused by low energy N + ion implantation and UV irradiation was also studied. the results showed that UV radiation is one effective means for streptomyces albus breeding. (authors)

  13. Evaluation of UV-permeability and photo-oxidisability of organic ultraviolet radiation-absorbing coatings

    Energy Technology Data Exchange (ETDEWEB)

    Li, Neng; Chen, Yuhe, E-mail: yuhec@sina.com; Bao, Yongjie; Zhang, Zeqian; Wu, Zaixing; Chen, Zhangmin

    2015-03-30

    Highlights: • We investigate organic UV radiation-absorbing coatings for use on bamboo surfaces. • The size of glass exactly inserted into sample cell of UV-Vis spectrophotometer. • A model was made to predict UV absorption of coatings. • We examine carbonyl groups change of coatings after ageing. • Two formulations which could effectively protect coating were obtained. - Abstract: Enhancing the durability of the coatings used on bamboo products is essential for increasing their use in outdoor environments. In this study, we investigated organic UV radiation-absorbing coatings for use on bamboo surfaces. The degree of resistance of the coatings, which contained 2-(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chlorinated benzotriazole (BTZ-1), to UV radiation degradation was determined through spectroscopic analysis. The critical BTZ-1 loading amount was determined by analysing the spectroscopic data. Fourier transform infrared spectroscopy was used to elucidate the relationship between the degree of photooxidation of the coatings and their BTZ-1 concentration. The experimental results showed that the coatings provided a high degree of shielding from UV radiation. The critical loading amount was determined to be 1.82 ± 0.05 g BTZ-1/m{sup 2}. The coatings formed using the formulations that contained 3 and 5 wt% BTZ-1 exhibited the lowest degree of photooxidation after exposure to UV radiation.

  14. UV lamp for photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Cardoso, M.J.B.; Landers, R.; Sundaram, V.S.

    1983-01-01

    An UV lamp and a differential pumping system which enables to couple the lamp to an ultra-high vacuum chamber (10 -9 torr) without using windows, are described. The differential between the pressure inside the discharge chamber and the one in de UHV region, which is of 10 8 -10 9 , is achieved with two pumping states separated by pyrex capillaries having an internal diameter of 0.6 mm. In the first stage, a mechanical pump (10 -3 torr) is used; in the second stage, a diffusor pump with a cryogenic trap (N 2 liq - 10 -7 torr) is employed. The lamp produces, when used with high purity He, narrow lines almost clear at 21.2 eV and 40.8 eV, depending on the discharge chamber pressure, thus eliminating the need of a monochromator. As a high voltage source (3 KV), a commercial unit with a good current control was used, ensuring UV beam stability - an essential characteristic for this lamp if it is employed for photoelectron excitation of crystalline samples. (C.L.B.) [pt

  15. High Energy, Single-Mode, All-Solid-State and Tunable UV Laser Transmitter

    Science.gov (United States)

    Prasad, Narasimha S.; Singh, Upendra N.; Hovis, FLoyd

    2007-01-01

    A high energy, single mode, all solid-state Nd:YAG laser primarily for pumping an UV converter is developed. Greater than 1 J/pulse at 50 HZ PRF and pulse widths around 22 ns have been demonstrated. Higher energy, greater efficiency may be possible. Refinements are known and practical to implement. Technology Demonstration of a highly efficient, high-pulse-energy, single mode UV wavelength generation using flash lamp pumped laser has been achieved. Greater than 90% pump depletion is observed. 190 mJ extra-cavity SFG; IR to UV efficiency > 21% (> 27% for 1 mJ seed). 160 mJ intra-cavity SFG; IR to UV efficiency up to 24% Fluence laser is being refined to match or exceed the above UV converter results. Currently the Nd:YAG pump laser development is a technology demonstration. System can be engineered for compact packaging.

  16. Efficiency of ocular UV protection by clear lenses.

    Science.gov (United States)

    Rifai, Katharina; Hornauer, Matthias; Buechinger, Ramona; Schoen, Roland; Barraza-Bernal, Maria; Habtegiorgis, Selam; Glasenapp, Carsten; Wahl, Siegfried; Mappes, Timo

    2018-04-01

    Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario.

  17. [Light protection: principles of UV protection].

    Science.gov (United States)

    Stege, H; Mang, R

    2006-05-01

    UV radiation is responsible for the induction of epithelial and melanocytic skin cancer, photoaging, and photodermatoses. UV protection is necessary to prevent damage caused by non-physiologic exposure. UV protection includes not only reduction of sun exposure but also use of sun protective filters, UV protective clothes, DNA repair enzymes, and antioxidant supplementation. Consumers are uncertain about the possibilities and limitations of commercial sun protection measures. Dermatologists must explain protective measures to the general public which continues to believe that UV-tanned skin is healthy. The sunscreen market is a highly competitive but lucrative market. The range of products with different designations and promises makes difficult for both consumers and dermatologists to determine what is sensible UV protection.

  18. UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report; UV-abhaengige Vitamin D Synthese. Bilanzierung der Expositionszeit durch UV zur Produktion des optimalen Vitamin D{sub 3}-Bedarfes im menschlichen Koerper. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

    2012-10-15

    simulated solar radiation or by sunbed UV lamps. All studies of the project (240 volunteers) were structured concerning UV skin type II and III, age and sex. In addition, data on the natural skin protection of the volunteers against UV radiation were measured in order to evaluate possible correlations between individual UV sensitivity and the efficiency of vitamin D synthesis. In result: In winter time, before starting the studies, the mean 25OH-vitamin D serum level of 18 ng/ml of the volunteers was in the deficiency range (< 20 ng/ml). UV exposures of 10 % MED applied twice a week vertically to face and hands caused significant increases of the 25OH-vitamin D serum level. The increase rised with higher UV doses and/or larger skin area exposed to UV radiation of the solar summer spectrum. While the increase of the 25OHvitamin D serum level in the UV cabinet was roughly independent from the basic level, under solar exposure conditions there were distinct variations between subjects as well as different outcomes for the whole group, which possibly depended on low outdoor temperatures during the solar exposures. Exposures by sunbed UV lamps lead to decreasing efficiencies in vitamin D production. An increase of the biologically effective UV dose and/or of the UV-exposed skin area decreased the vitamin D efficiency down to 30 % compared to simulated solar radiation. Because of strong differences in UV erythema sensitivity of the skin of different anatomical locations, we hypothesized similar relations in the efficiency of UV-induced vitamin D synthesis. The efficiency of UV-induced vitamin D synthesis varies up to 400 % between the anatomical locations of the body. The investigation of the content of provitamin D (7-Dehydrocholesterol), the source of the vitamin D synthesis in the skin, and of the influence of UV exposure on the level of this content results in new findings, too. Suberythemal UV exposures do not influence the 7-DHC-concentration in the skin. 1 MED leads to a

  19. [Genetic control of the sensitivity of Aspergillus nidulans to mutagenic factors. VII. Inheritance of cross-sensitivity to different mutagenic factors by uvs-mutants].

    Science.gov (United States)

    Evseeva, G V; Kameneva, S V

    1977-01-01

    To study the inheritance of the sensitivity to UV, X-rays, methylmethanesulphonate (MMS), nitrosoguanidine (NG) and nitrous acid (NA) in five uvs mutants of Aspergillus nidulans, having multiple sensitivity to these factors, the sensitivity of recombinants obtained from crossing uvs mutants with uvs+ strain, resistant to all the factors analysed, and uvs leads to uvs+ revertants is investigated. Four uvs mutants (15, 17, 19 and 26) are found to have a nomogenic control of sensitivity to different mutagens. In one mutant (uvs11) the sensitivity to five factors is controlled by two non-linked mutations, one of them determining the sensitivity to UV, NG, NA, and the other--to X-rays and MMC. Phenotypic manifestations of uvs mutations is modified by cell genotype, both chromosomal and cytoplasmic factors being responsible for the modification. Phenotypic modification of uvs mutation results in the change to some (but not to all) mutagenic factors. It suggests, that not the product of uvs gene, but some other components of the reparation complex are modified. Otherwise, reparation of different DNA damages can be carried out by a single enzyme acting in different reparation complexes.

  20. Erythemal solar UV measurement network in New Zealand

    International Nuclear Information System (INIS)

    Smith, G.J.

    1993-01-01

    Measured daily total erythemal doses for 1989, 1990 and 1991 were presented and the cloudless-sky daily dose at the autumn equinox was approximately 30-50% higher than at the spring equinox as a result of the seasonal variation in ozone levels. In addition a substantially lower spring equinox erythemal dose was observed in 1991, probably as a result of increased aerosols arising from the Pinatubo eruption. An asymmetry in the diurnal pattern of irradiances about solar noon has been observed on cloudless days. Higher UV irradiances have been usually observed in the afternoons than in the mornings. Measurement of erythemal radiation is needed for skin cancer epidemiology projects. Given the uncertainties relating to the exposure of individuals to solar erythemal radiation, personal dosimeters may be very useful in providing more reliable personal UV exposure data. (author). 4 refs

  1. Cavity-mirror degradation in the deep-UV FEL

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, K.; Yamazaki, T.; Sei, N. [Electrotechnical Lab., Ibaraki (Japan)] [and others

    1995-12-31

    It is known that the degradation of dielectric multilayer mirrors used in short wavelength free-electron lasers (FELs) is caused by the carbon contamination on the mirror surface and the defects inside the dielectrics. We reported last year that the degraded dielectric multilayer mirrors can be repaired with both surface treatment by RF-induced oxygen plasma and thermal annealing. However, such a mirror degradation is still one of the most critical issues in the deep ultraviolet (UV) FELs, because the fundamental undulator radiation resonating in the laser cavity, the intensity of which is much higher than that of higher harmonics, can be sufficiently energetic to cause the mirror degradation through photochemical reactions. We are investigating the mirror degradation mainly in the deep UV region down to 240 nm. The experimental results will be shown. The mirror degradation mechanism will be discussed.

  2. The role of coccoliths in protecting Emiliania huxleyi against stressful light and UV radiation

    Science.gov (United States)

    Xu, Juntian; Bach, Lennart T.; Schulz, Kai G.; Zhao, Wenyan; Gao, Kunshan; Riebesell, Ulf

    2016-08-01

    Coccolithophores are a group of phytoplankton species which cover themselves with small scales (coccoliths) made of calcium carbonate (CaCO3). The reason why coccolithophores form these calcite platelets has been a matter of debate for decades but has remained elusive so far. One hypothesis is that they play a role in light or UV protection, especially in surface dwelling species like Emiliania huxleyi, which can tolerate exceptionally high levels of solar radiation. In this study, we tested this hypothesis by culturing a calcified and a naked strain under different light conditions with and without UV radiation. The coccoliths of E. huxleyi reduced the transmission of visible radiation (400-700 nm) by 7.5 %, that of UV-A (315-400 nm) by 14.1 % and that of UV-B (280-315 nm) by 18.4 %. Growth rates of the calcified strain (PML B92/11) were about 2 times higher than those of the naked strain (CCMP 2090) under indoor constant light levels in the absence of UV radiation. When exposed to outdoor conditions (fluctuating sunlight with UV radiation), growth rates of calcified cells were almost 3.5 times higher compared to naked cells. Furthermore, the relative electron transport rate was 114 % higher and non-photochemical quenching (NPQ) was 281 % higher in the calcified compared to the naked strain, implying higher energy transfer associated with higher NPQ in the presence of calcification. When exposed to natural solar radiation including UV radiation, the maximal quantum yield of photosystem II was only slightly reduced in the calcified strain but strongly reduced in the naked strain. Our results reveal an important role of coccoliths in mitigating light and UV stress in E. huxleyi.

  3. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  4. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  5. Ultraviolet light-resistant primary transfectants of xeroderma pigmentosum cells are also DNA repair-proficient

    International Nuclear Information System (INIS)

    Stark, M.; Naiman, T.; Canaani, D.

    1989-01-01

    In a previous work, an immortal xeroderma pigmentosum cell line belonging to complementation group C was complemented to a UV-resistant phenotype by transfection with a human cDNA clone library. We now report that the primary transformants selected for UV-resistance also acquired normal levels of DNA repair. This was assessed both by measurement of UV-induced [ 3 H]thymidine incorporation and by equilibrium sedimentation analysis of repair-DNA synthesis. Therefore, the transduced DNA element which confers normal UV-resistance also corrects the excision repair defect of the xeroderma pigmentosum group C cell line

  6. Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1-xN Buffer Layer.

    Science.gov (United States)

    Lee, Chang-Ju; Won, Chul-Ho; Lee, Jung-Hee; Hahm, Sung-Ho; Park, Hongsik

    2017-07-21

    The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded Al x Ga -x N buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded Al x Ga 1-x N buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10 - ² A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

  7. UV-vis light transmittance through tinted contact lenses and the effect of color on values.

    Science.gov (United States)

    Osuagwu, Uchechukwu L; Ogbuehi, Kelechi C

    2014-06-01

    To assess the transmittance, in the 200-700nm electromagnetic radiation spectrum, by popularly used tinted soft contact lenses (CLs). The spectra transmittances of ultraviolet (UV)-blocking (I Day Acuvue Define, Freshlook ONE DAY) and non-UV-blocking (Durasoft 3, Tutti, and NeoCosmo) tinted soft CLs were tested. The transmittance of each lens, including nine different colors of Freshlook CL was recorded on spectrophotometer, and the data used to also calculate a UV protection factor (PF) for each lens brand tested, with a higher value indicating a higher level of protection. The UV-blocking CLs significantly reduced UVC, UVB & UVA transmission and thereby meet the American National Standards Institution standard for class 2 UV blockers: a maximum of 30% transmittance of UVA and 5% transmittance of UVB wavelengths. In contrast, the Durasoft 3, Tutti, and NeoCosmo CLs demonstrated negligible UV-blockage. The Acuvue Define CL offered the greatest protection from UVC (PF=69) and UVB (PF=55), but with only 35% luminous transmittance, while the Freshlook CL (especially gemstone green) offered the best protection from UVA (PF=24) and showed about 55% translucency. Overall, the UV-blocking CLs performed equally well across the UV spectrum. Different colors of Freshlook CL transmitted statistically and clinically significantly different amounts of visible light but similar amounts of UVR. Freshlook and Acuvue Define CLs which are designated as UV-blockers significantly reduced UVR transmission to safe levels whereas Tutti, NeoCosmo and Durasoft 3 did not. Transmission within the Freshlook CL family was more dependent on color in the visible light spectrum, but not in the UV-spectrum, where the gemstone green performing best among the tested colors. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  8. Synergistic effect of ultrasonic pre-treatment combined with UV irradiation for secondary effluent disinfection.

    Science.gov (United States)

    Jin, Xin; Li, Zifu; Xie, Lanlan; Zhao, Yuan; Wang, Tingting

    2013-11-01

    The ultraviolet (UV) disinfection efficiency is often affected by suspended solids (SS). Given their high concentration or large particle size, SS can scatter UV light and provide shielding for bacteria. Thus, ultrasound is often employed as a pre-treatment process to improve UV disinfection. This work investigated the synergistic effect of ultrasound combined with UV for secondary effluent disinfection. Bench-scale experiments were conducted in using samples obtained from secondary sedimentation tanks. These tanks belonged to three wastewater treatment plants in Beijing that use different kinds of biological treatment methods. Several parameters may contribute to the changes in the efficiency of ultrasound and UV disinfection. Thus, the frequency and energy density of ultrasound, as well as the SS, were investigated. Results demonstrated that samples which have relatively higher SS concentrations or higher percentages of larger particles have less disinfection efficiency using UV disinfection alone. However, the presence of ultrasound could improve the disinfection efficiency because it has synergistic effect. Changes in the particle size distribution and SS concentration notably affected the efficiency of UV disinfection. The efficiency of Escherichia coli elimination can be decreased by 1.2 log units as the SS concentration increases from 16.9 mg/l to 25.4 mg/l at a UV energy density of 40 mJ/cm(2). UV disinfection alone reduced the E. coli population by 3.4 log units. However, the synergistic disinfection of ultrasound and UV could reach 5.4 log units during the reduction of E. coli at a 40 kHz frequency and an energy density of 2.64 kJ/l. The additional synergistic effect is 1.1 log units. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. The UV Survey Mission Concept, CETUS

    Science.gov (United States)

    Heap, Sara; and the CETUS Team

    2018-01-01

    In March 2017, NASA selected CETUS for study of a Probe-class mission concept. W. Danchi is the CETUS PI, and S. Heap is the Science PI. CETUS is primarily a UV survey telescope to complement survey telescopes of the 2020’s including E-ROSITA, Subaru Hyper Suprime Cam and Prime-Focus Spectrograph, WFIRST, and the Square Kilometer Array. CETUS comprises a 1.5-m wide-field telescope and three science instruments: a wide-field (1045” on a side) far-UV and near-UV camera; a similarly wide-field near-UV multi-object spectrograph utilizing a next-generation micro-shutter array; and a single-object spectrograph with options of spectral region (far-UV or near-UV) and spectral resolving power (2,000 or 40,000). The survey instruments will operate simultaneously thereby producing wide-field images in the near-UV and far-UV and a spectrogram containing near-UV spectra of up to 100 sources free of spectral overlap and astronomical background. ln concert with other survey telescopes, CETUS will focus on understanding galaxy evolution at cosmic noon (z~1-2).

  10. UV tanning advertisements in national high school newspapers

    OpenAIRE

    Lofgreen, Seth J; Domozych, Renee; Doctor, Monica; Reimer, Christine; Self, Alyssa; Dellavalle, Robert P

    2017-01-01

    Many young adults have utilized indoor ultraviolet(UV) tanning, putting them at higher risk fordevelopment of skin cancers. Prior to the increasedregulations on indoor tanning for minors, indoortanning businesses marketed to teens throughmodalities such as advertisements in high schoolnewspapers. The purpose of this study was toquantify tanning advertisements in high schoolnewspapers published across the United Statesbetween August 2014 and July 2015. Online versionsof the newspaper issues we...

  11. UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

    Energy Technology Data Exchange (ETDEWEB)

    Zebbar, N., E-mail: nacbar2003@yahoo.fr [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Chabane, L. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Gabouze, N. [CRTSE, 02 Bd. Frantz Fanon, BP 140, Algiers (Algeria); Kechouane, M. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Trari, M. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32, El-Alia, Algiers (Algeria); Aida, M.S. [LCM et Interface, Faculty of Sciences, University of Constantine, 25000 (Algeria); Belhousse, S. [CRTSE, 02 Bd. Frantz Fanon, BP 140, Algiers (Algeria); Hadj Larbi, F. [MEMS & Sensors, Division Microélectronique et Nanotechnologie, Centre de Développement des Technologies Avancées (CDTA), BP 17, Baba Hassen, Algiers (Algeria)

    2016-04-30

    Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400 °C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432 nm) prevails for low film resistivity, ranging from 10{sup −2} to 1 Ω·cm. By contrast, for higher resistivity (> 1 Ω·cm), there is a predominance of the UV band (382 nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250 °C was about 80 mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications. - Highlights: • Properties of ZnO thin films grown by Ultrasonic Spray Pyrolysis at 350 °C. • Photoluminescence emission intensity in undoped ZnO film: effect of the resistivity • Photoluminescence emission intensity of In-doped ZnO film is resistivity dependent. • The spectral response of ZnO:In/Si hetero-junction deposited in the range (250–400 °C)

  12. UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

    International Nuclear Information System (INIS)

    Zebbar, N.; Chabane, L.; Gabouze, N.; Kechouane, M.; Trari, M.; Aida, M.S.; Belhousse, S.; Hadj Larbi, F.

    2016-01-01

    Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400 °C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432 nm) prevails for low film resistivity, ranging from 10 −2 to 1 Ω·cm. By contrast, for higher resistivity (> 1 Ω·cm), there is a predominance of the UV band (382 nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250 °C was about 80 mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications. - Highlights: • Properties of ZnO thin films grown by Ultrasonic Spray Pyrolysis at 350 °C. • Photoluminescence emission intensity in undoped ZnO film: effect of the resistivity • Photoluminescence emission intensity of In-doped ZnO film is resistivity dependent. • The spectral response of ZnO:In/Si hetero-junction deposited in the range (250–400 °C)

  13. UV- and gamma-radiation sensitive mutants of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Jiang, C.Z.; Yen, C.N.; Cronin, K.; Mitchell, D.; Britt, A.B.

    1997-01-01

    Arabidopsis seedlings repair UV-induced DNA damage via light-dependent and -independent pathways. The mechanism of the ''dark repair'' pathway is still unknown. To determine the number of genes required for dark repair and to investigate the substrate-specificity of this process we isolated mutants with enhanced sensitivity to UV radiation in the absence of photoreactivating light. Seven independently derived UV sensitive mutants were isolated from an EMS-mutagenized population. These fell into six complementation groups, two of which (UVR1 and UVH1) have previously been defined. Four of these mutants are defective in the dark repair of UV-induced pyrimidine [6-4] pyrimidinone dimers. These four mutant lines are sensitive to the growth-inhibitory effects of gamma radiation, suggesting that this repair pathway is also involved in the repair of some type of gamma-induced DNA damage product. The requirement for the coordinate action of several different gene products for effective repair of pyrimidine dimers, as well as the nonspecific nature of the repair activity, is consistent with nucleotide excision repair mechanisms previously described in Saccharomyces cerevisiae and nonplant higher eukaryotes and inconsistent with substrate-specific base excision repair mechanisms found in some bacteria, bacteriophage, and fungi. (author)

  14. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Khatri, Zeeshan, E-mail: zeeshan.khatri@faculty.muet.edu.pk [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Ali, Shamshad [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Khatri, Imran [Department of Entomology, Sindh Agriculture University, Tandojam (Pakistan); Mayakrishnan, Gopiraman [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Kim, Seong Hun [Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ick-Soo, E-mail: kim@shinshu-u.ac.jp [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

    2015-07-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage.

  15. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    International Nuclear Information System (INIS)

    Khatri, Zeeshan; Ali, Shamshad; Khatri, Imran; Mayakrishnan, Gopiraman; Kim, Seong Hun; Kim, Ick-Soo

    2015-01-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage

  16. Ultraviolet radiation resistance in Halobacterium salinarium

    International Nuclear Information System (INIS)

    Kristoff, S.R.

    1985-01-01

    An obvious characteristic of wild type H. salinarium is its red pigmentation. A non-pigmented mutant was isolated to test the role of pigmentation in UV radiation resistance. Survival curves of UV-irradiated wild type and mutant cells show that pigmentation does not play a direct role in protecting DNA from UV damage. Pigmentation does play a role, however, in repairing UV damage. UV-irradiated wild type cells show more efficient recovery by photoreactivation with 405 nm light than do UV-irradiated non-pigmented mutants. High internal cation concentrations found in H. salinarium may also be partly responsible for the relative resistance of H. salinarium to UV radiation by causing the DNA to assume a conformation less conducive to the production of pyrimidine dimers. In vitro irradiation of DNA extracted from H. salinarium, dissolved in solutions of different ionic strengths, indicate that pyrimidine dimers may not form as readily in DNA which is in an environment with high salt concentration

  17. Cyclobutyl pyrimidine dimer accumulation in relation to UV-B sensitivity in mung bean cultivars

    International Nuclear Information System (INIS)

    He Junmin; Wang Ruibin; Meng Zhaoni

    2006-01-01

    The purpose of the experiment is to reveal the relationship between cyclobutyl pyrimidine dimers (CPDs) accumulation and UV-B sensitivity in mung bean cultivars. Two mung bean cultivars (Phaseolus raditus L. cv. Qindou -2 0 and Zhonglü -1 ) were grown in greenhouse with treatment or without treatment of UV-B radiation (0.4 W * m -2 ) for four days. The UV-B-induced CPDs in mung bean DNA were quantified by enzyme-linked immunosorbent assay (ELISA) with specific monoclonal antibody and the relationship between CPDs accumulation and the UV-B sensitivity of mung bean seedlings were discussed. The UV-B-induced inhibition of the biomass and net photosynthetic rate of the primary leaves of cultivar Zhonglü -1 were respectively lower than that of cultivar Qindou -2 0, so that the cultivar Zhonglü -1 was more tolerant to UV-B than the cultivar Qindou -2 0. Meanwhile, the cultivar Zhonglü -1 had lower CPD accumulation and susceptibility to CPD induction, higher photorepair capacity and same dark repair capacity as compared with the cultivar Qindou -2 0. Different UV-B sensitivities between two mung bean cultivars may be mainly caused by the differences in CPD accumulation, which are caused by the different susceptibility to CPD induction and the different photorepair capacities. In addition, the different susceptibility to CPD induction between two mung bean cultivars is related to the different levels of UV-absorbing compounds

  18. UV irradiation assisted growth of ZnO nanowires on optical fiber surface

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Bo; Shi, Tielin; Liao, Guanglan; Li, Xiaoping; Huang, Jie; Zhou, Temgyuan; Tang, Zirong, E-mail: zirong@mail.hust.edu.cn

    2017-06-01

    Highlights: • A new fabrication process combined a hydrothermal process with UV irradiation from optical fiber is developed. • The growth of ZnO nanowires is efficient in the utilization of UV light. • A novel hybrid structure which integrates ZnO nanowires on optical fiber surface is synthesized. • The UV assisted growth of ZnO nanowires shows preferred orientation and better quality. • A mechanism of growing ZnO nanowires under UV irradiation is proposed. - Abstract: In this paper, a novel approach was developed for the enhanced growth of ZnO nanowires on optical fiber surface. The method combined a hydrothermal process with the efficient UV irradiation from the fiber core, and the effects of UV irradiation on the growth behavior of ZnO nanowires were investigated. The results show that UV irradiation had great effects on the preferred growth orientation and the quality of the ZnO nanowires. The crystallization velocity along the c-axis would increase rapidly with the increase of the irradiation power, while the growth process in the lateral direction was marginally affected by the irradiation. The structure of ZnO nanowires also shows less oxygen vacancy with UV irradiation of higher power. The developed approach is applicable for the efficient growth of nanowires on the fiber surface, and the ZnO nanowires/optical fiber hybrid structures have great potentials for a wide variety of applications such as optical fiber sensors and probes.

  19. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    KAUST Repository

    Garcia-Corral, Lara S.

    2015-07-07

    The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota. Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP) of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3°C), alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced NCP and resulted in a heterotrophic (NCP < 0) metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV × Temp) was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2−O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle.

  20. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    Directory of Open Access Journals (Sweden)

    Lara S. eGarcia-Corral

    2015-07-01

    Full Text Available The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota.Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3ºC, alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced net community production and resulted in a heterotrophic (NCP<0 metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV x Temp was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2-O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle

  1. Biological UV-doses and the effect on an ozone layer depletion

    International Nuclear Information System (INIS)

    Dahlback, A.; Henriksen, T.

    1988-08-01

    Effective UV-doses were calculated based on the integrated product of the biological action spectrum and the solar radiation. The calculations included absorption and scattering of UV-radiation in the atmosphere, both for normal ozone conditions as well as for a depleted ozone layer. The effective annual UV-dose increases by approximately 4% per degree of latitude towards the equator. An ozone depletion of 1% increases the annual UV-dose by approximately 1% at 60 o N. A large depletion of 50% over Scandinavia (60 o N) would give this region an effective UV-dose similar to that obtained, with normal ozone conditions, at a latitude of 40 o N (California or the Mediterranean countries). The Antarctic ozone hole increases the annual UV-dose by 20 to 25% which is a similar increase as that attained by moving 5 to 6 degrees of latitude nearer the equator. The annual UV-dose on higher latitudes is mainly determined by the summer values of ozone. Both the ozone values and the effective UV-doses vary from one year to another (within ±4%). No positive or negative trend is observed for Scandinavia from 1978 to 1988

  2. UV-deprived coloration reduces success in mate acquisition in male sand lizards (Lacerta agilis.

    Directory of Open Access Journals (Sweden)

    Mats Olsson

    Full Text Available Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles. Our previous work on the Swedish sand lizard (Lacerta agilis has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green 'badge' on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined.Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only had significantly higher success in mate acquisition than UV-deprived males.These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

  3. UV-activated persulfate oxidation and regeneration of NOM-Saturated granular activated carbon.

    Science.gov (United States)

    An, Dong; Westerhoff, Paul; Zheng, Mengxin; Wu, Mengyuan; Yang, Yu; Chiu, Chao-An

    2015-04-15

    A new method of ultraviolet light (UV) activated persulfate (PS) oxidation was investigated to regenerate granular activated carbon (GAC) in drinking water applications. The improvements in iodine and methylene blue numbers measured in the GAC after ultraviolet- (UV) activated persulfate suggested that the GAC preloaded with natural organic matter (NOM) was chemically regenerated. An experimental matrix for UV-activated persulfate regeneration included a range of persulfate doses and different UV wavelengths. Over 87% of the initial iodine number for GAC was restored under the optimum conditions, perfulfate dosage 60 g/L and UV exposure 1.75 × 10(4) mJ/cm(2). The persulfate dosages had little effect on the recovery of the methylene blue number, which was approximately 65%. Persulfate activation at 185 nm was superior to activation at 254 nm. UV activation of persulfate in the presence of GAC produced acid, lowering the solution pH. Higher persulfate concentrations and UV exposure resulted in greater GAC regeneration. Typical organic and inorganic byproducts (e.g., benzene compounds and sulfate ions) were measured as a component of treated water quality safety. This study provides a proof-of-concept that can be used to optimize pilot-scale and full-scale UV-activated persulfate for regeneration of NOM-saturated GAC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Crosstalk between MAV and MEP pathways in vitro grape plants exposed to UV-B radiation

    International Nuclear Information System (INIS)

    Gil, M.; Bottini, R.; Piccoli, P.; Pontin, M.

    2010-01-01

    The synthesis of terpenoids from IPP (isopentenyl diphosphate) proceeds in plants throughout two pathways, the MVA (mevalonic acid) in cytosol and the MEP (2-C-methyl-D-erythritol 4-phosphate) in plastids. Ultraviolet-B (UV-B) radiation induced the synthesis of terpenes in in vitro grape plants according to the fluence rate. Low intensity UV-B promoted the MVA pathway while high intensity UV-B stimulated the MEP pathway. Mevastatin is known to inhibit the enzyme HMG-CoA reductase blocking terpene synthesis in cytosol. In vitro plants growing 45 days under 16 h-photoperiod (100 μmol m - 2 s - 1) were fed at the apex with mevastatin and then exposed to an UV-B dose administrated at two intensities: low UV-B (8.25 μW cm - 2,16 h) or high UV-B (33 μW cm - 2,4 h). Methanol: chloroform extracts were analyzed by GC-EIMS and compared with controls without mevastatin. Levels of γ-Sitosterol and Stigmasterol were significantly increased under low intensity UV-B in the controls. The plants treated with the inhibitor showed a significant decrease of both sterols and a decrease in the plastidial terpenes but sterols were higher under UV-B. These results suggest an IPP crosstalk between the MAV and MEP pathways under restrictive conditions. (authors)

  5. Applicability of integrated cell culture quantitative PCR (ICC-qPCR) for the detection of infectious adenovirus type 2 in UV disinfection studies

    Science.gov (United States)

    Human adenovirus is relatively resistant to UV radiation and has been used as a conservative testing microbe for evaluations of UV disinfection systems as components of water treatment processes. In this study, we attempted to validate the applicability of integrated cell culture...

  6. Enhancement of growth, photosynthetic performance and yield by exclusion of ambient UV components in C3 and C4 plants.

    Science.gov (United States)

    Kataria, Sunita; Guruprasad, K N; Ahuja, Sumedha; Singh, Bupinder

    2013-10-05

    A field experiment was conducted under tropical climate for assessing the effect of ambient UV-B and UV-A by exclusion of UV components on the growth, photosynthetic performance and yield of C3 (cotton, wheat) and C4 (amaranthus, sorghum) plants. The plants were grown in specially designed UV exclusion chambers, wrapped with filters that excluded UV-B (plant species responded to UV exclusion by a significant increase in plant height, leaf area, leaf biomass, total biomass accumulation and yield. Measurements of the chlorophyll, chlorophyll fluorescence parameters, gas exchange parameters and the activity of Ribulose-1,5-bisphosphate carboxylase (Rubisco) by fixation of (14)CO2 indicated a direct relationship between enhanced rate of photosynthesis and yield of the plants. Quantum yield of electron transport was enhanced by the exclusion of UV indicating better utilization of PAR assimilation and enhancement in reducing power in all the four plant species. Exclusion of UV-B in particular significantly enhanced the net photosynthetic rate, stomatal conductance and activity of Rubisco. Additional fixation of carbon due to exclusion of ambient UV-B was channeled towards yield as there was a decrease in the level of UV-B absorbing substances and an increase in soluble proteins in all the four plant species. The magnitude of the promotion in all the parameters studied was higher in dicots (cotton, amaranthus) compared to monocots (wheat, sorghum) after UV exclusion. The results indicated a suppressive action of ambient UV-B on growth and photosynthesis; dicots were more sensitive than monocots in this suppression while no great difference in sensitivity was found between C3 and C4 plants. Experiments indicated the suppressive action of ambient UV on carbon fixation and yield of C3 and C4 plants. Exclusion of solar UV-B will have agricultural benefits in both C3 and C4 plants under tropical climate. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. nitrosoguanidine-induced cadmium resistant mutants of Aspergillus

    Indian Academy of Sciences (India)

    Unknown

    nitrosoguanidine-induced cadmium resistant mutants of. Aspergillus niger. SAMAR ... gens and UV irradiation to study transportation of cad- mium ion through cell ..... Rowley W S 1993 Yeast bZib proteins mediate pleiotropic drug and metal ...

  8. UV-extending Ghost Inflation

    CERN Document Server

    Ivanov, Mikhail M

    2014-01-01

    We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether theory or its khronometric version. Compared to previous works on ghost inflation our setup allows to go beyond the study of small perturbations and include the background dynamics in a unified framework. In the specific regime when the expansion of the Universe is dominated by the kinetic energy of the inflaton we find that the model predicts rather high tensor-to-scalar ratio r ~ 0.02 $\\div$ 0.2 and non-Gaussianity of equilateral type with f_NL in the range from -50 to -5.

  9. Short-term stress enhances cellular immunity and increases early resistance to squamous cell carcinoma.

    Science.gov (United States)

    Dhabhar, Firdaus S; Saul, Alison N; Daugherty, Christine; Holmes, Tyson H; Bouley, Donna M; Oberyszyn, Tatiana M

    2010-01-01

    In contrast to chronic/long-term stress that suppresses/dysregulates immune function, an acute/short-term fight-or-flight stress response experienced during immune activation can enhance innate and adaptive immunity. Moderate ultraviolet-B (UV) exposure provides a non-invasive system for studying the naturalistic emergence, progression and regression of squamous cell carcinoma (SCC). Because SCC is an immunoresponsive cancer, we hypothesized that short-term stress experienced before UV exposure would enhance protective immunity and increase resistance to SCC. Control and short-term stress groups were treated identically except that the short-term stress group was restrained (2.5h) before each of nine UV-exposure sessions (minimum erythemal dose, 3-times/week) during weeks 4-6 of the 10-week UV exposure protocol. Tumors were measured weekly, and tissue collected at weeks 7, 20, and 32. Chemokine and cytokine gene expression was quantified by real-time PCR, and CD4+ and CD8+ T cells by flow cytometry and immunohistochemistry. Compared to controls, the short-term stress group showed greater cutaneous T-cell attracting chemokine (CTACK)/CCL27, RANTES, IL-12, and IFN-gamma gene expression at weeks 7, 20, and 32, higher skin infiltrating T cell numbers (weeks 7 and 20), lower tumor incidence (weeks 11-20) and fewer tumors (weeks 11-26). These results suggest that activation of short-term stress physiology increased chemokine expression and T cell trafficking and/or function during/following UV exposure, and enhanced Type 1 cytokine-driven cell-mediated immunity that is crucial for resistance to SCC. Therefore, the physiological fight-or-flight stress response and its adjuvant-like immuno-enhancing effects, may provide a novel and important mechanism for enhancing immune system mediated tumor-detection/elimination that merits further investigation.

  10. Cloning of the DNA repair gene, uvsF, by transformation of Aspergillus nidulans.

    Science.gov (United States)

    Oza, K; Käfer, E

    1990-06-01

    As a first step in the cloning of the DNA repair gene uvsF of Aspergillus nidulans, uvsF pyrG double mutant strains were transformed with a genomic library which carried the complementing Neurospora pyr-4 gene in the vector. Rare pyr+ uvs+ cotransformants were obtained on media lacking pyrimidines, overlayed with MMS (methyl-methane sulfonate) to which uvsF is hypersensitive. Among MMS-resistant transformants, Southerns revealed two types which showed single bands of different sizes when BglII-digested genomic DNA was probed with the vector. Both types produced uvsF- recombinants without vector sequences in homozygous crosses, but only those with the larger band also produced haploid uvs+ progeny. Using BglII-digested genomic DNA to transform Escherichia coli, plasmids of the corresponding two sizes could be rescued. Their inserts had a short internal region in common, giving evidence of rearrangement(s). In secondary transformation of uvsF mutants, only the plasmids with the larger insert showed complementation and these were used to screen Aspergillus libraries. Three types of genomic and two overlapping cDNA clones were identified. The cDNAs hybridized not only to each other, but also to the common region of the rescued plasmids. Therefore, cDNA subclones were used to map the putative uvsF sequences to a short segment in one genomic clone. In Northerns, the complementing large plasmid hybridized to three mRNAs, while the cDNA subclone identified one of these as the probable uvsF message.

  11. A comparative approach of methylparaben photocatalytic degradation assisted by UV-C, UV-A and Vis radiations.

    Science.gov (United States)

    Doná, Giovanna; Dagostin, João Luiz Andreoti; Takashina, Thiago Atsushi; de Castilhos, Fernanda; Igarashi-Mafra, Luciana

    2018-05-01

    Due to the widespread use of methylparaben (MEP) and its high chemical stability, it can be found in wastewater treatment plants and can act as an endocrine disrupting compound. In this study, the photocatalytic degradation and mineralization of MEP solutions were evaluated under UV-A, UV-C and Vis radiations in the presence of the photocatalyst TiO 2 . In this sense, the effects of the catalyst load, pH and MEP initial concentration were studied. Remarkably higher reaction rates and total photodegradation were achieved in systems assisted by UV-C radiation. The complete degradation was achieved after 60 min of reaction using the MEP concentration of 30 mg L -1 at pH 9 and 500 mg L -1 TiO 2 . The experimental data apparently followed a Langmuir-Hinshelwood kinetic model, which could predict 88-98% of the reaction behavior. For the best photodegradation condition, the model predicted an apparent reaction rate constant (k app ) equal to 0.0505 min -1 and an initial reaction rate of 1.5641 mg (L min) -1 . Mineralization analyses showed high removal for MEP and derived compounds from the initial solution when using UV-C after 90 min of reaction. The lower toxicity was also confirmed by in vivo tests using MEP solutions previously treated by photocatalysis.

  12. Photocatalytic degradation of p,p'-DDT under UV and visible light using interstitial N-doped TiO₂.

    Science.gov (United States)

    Ananpattarachai, Jirapat; Kajitvichyanukul, Puangrat

    2015-01-01

    1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (or p,p'-DDT) is one of the most persistent pesticides. It is resistant to breakdown in nature and cause the water contamination problem. In this work, a major objective was to demonstrate the application of N-doped TiO2 in degradation and mineralization of the p,p'-DDT under UV and visible light in aqueous solution. The N-doped TiO2 nanopowders were prepared by a simple modified sol-gel procedure using diethanolamine (DEA) as a nitrogen source. The catalyst characteristics were investigated using XRD, SEM, TEM, and XPS. The adsorption and photocatalytic oxidation of p,p'-DDT using the synthesized N-doped TiO2 under UV and visible light were conducted in a batch photocatalytic experiment. The kinetics and p,p'-DDT degradation performance of the N-doped TiO2 were evaluated. Results show that the N-doped TiO2 can degrade p,p'-DDT effectively under both UV and visible lights. The rate constant of the p,p'-DDT degradation under UV light was only 0.0121 min(-1), whereas the rate constant of the p,p'-DDT degradation under visible light was 0.1282 min(-1). Under visible light, the 100% degradation of p,p'-DDT were obtained from N-doped TiO2 catalyst. The reaction rate of p,p'-DDT degradation using N-doped TiO2 under visible light was sixfold higher than that under UV light. According to Langmuir-Hinshelwood model, the adsorption equilibrium constant (K) for the N-doped TiO2 under visible light was 0.03078 L mg(-1), and the apparent reaction rate constant (k) was 1.3941 mg L(-1)-min. Major intermediates detected during the p,p'-DDT degradation were p,p'-DDE, o,p'-DDE, p,p'-DDD and p,p'-DDD. Results from this work can be applied further for the breakdown of p,p'-DDT molecule in the real contaminated water using this technology.

  13. Enhancement of SV40 transformation by treatment of C3H2K cells with uv light and caffeine. I. Combined effect of uv light and caffeine

    International Nuclear Information System (INIS)

    Ide, T.; Anzai, K.; Andoh, T.

    1975-01-01

    Treatment of cultured mouse cells, C3H2K, with uv light and/or caffeine enhanced the frequency of SV40-induced transformation. This enhancement depends upon the doses of uv and caffeine and the mode of combination of these agents. Irradiation of cells with increasing doses of uv just before infection resulted in approximately 2-fold enhancement of the transformation frequency up to a dose of 90 ergs/mm 2 and 3.3-fold at 150 ergs/mm 2 . Addition of 1 mM caffeine to the medium for 4 days subsequent to infection brought about a 2-fold enhancement. When cells were irradiated and treated with 1 mM caffeine, the enhancement was approximately 4-fold up to a uv dose of 90 ergs/mm 2 and 5.9-fold at 150 ergs/mm 2 . When 0.1 to 4 mM caffeine was added for 4 days postinfection, the absolute number of transformations increased, and an enhancement ratio of 1.3 to 6.8 resulted. After the addition of the same increasing doses of caffeine to uv-irradiated cells (75 ergs/mm 2 ), the enhancement of transformation frequency was even higher ranging 2.0 to 13.3. The transformation frequencies thus obtained by the double treatment were always higher than those predicted if uv and caffeine acted additively. The transformation frequency was little affected by the addition of dibutyrylcyclic AMP and theophylline

  14. Expression of UV-irradiated adenovirus in normal and UV-sensitive Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1985-01-01

    The chinese hamster ovary (CHO) cell mutants UV-20, UV-24, and UV-41 are abnormally sensitive to UV and harbour various defects lin their ability to repair cellular DNA. This study has examined the expression of UV-irradiated AD2 in these cells. HCR of UV-irradiated Ad2, as measured by viral structural antigen (Vag) formation or progeny production, was found to be similar for the normal and the UV-sensitive CHO strains. UV-irradiation of Ad2 (1200 J/m/sup 2/) resulted in a delay of Vag expression of 18 hours in normal human fibroblasts, which is thought to reflect the time required for removal of UV-induced lesions from the DNA before viral DNA synthesis can proceed. However, a similar UV-irradiation of Ad2 did not result in a delay of Vag expression for infection of CHO cells, suggesting that UV-induced lesions in Ad2 DNA do not inhibit its replication in CHO cells. These results indicate a fundamental difference in the processing of UV-irradiated AD2-DNA in CHO as compared to human cells

  15. Impact of asymmetric lamp positioning on the performance of a closed-conduit UV reactor

    Directory of Open Access Journals (Sweden)

    Tipu Sultan

    2017-06-01

    Full Text Available Computational fluid dynamics (CFD analyses for the performance improvement of a closed-conduit ultraviolet (UV reactor were performed by changing the lamp positions from symmetric to asymmetric. The asymmetric lamp positioning can be useful for UV reactor design and optimization. This goal was achieved by incorporating the two performance factors, namely reduction equivalent dose (RED and system dose performance. Four cases were carried out for asymmetric lamp positioning within the UV reactor chamber and each case consisted of four UV lamps that were simulated once symmetrically and four times asymmetrically. The results of the four asymmetric cases were compared with the symmetric one. Moreover, these results were evaluated by using CFD simulations of a closed-conduit UV reactor. The fluence rate model, UVCalc3D was employed to validate the simulations results. The simulation results provide detailed information about the dose distribution, pathogen track modeling and RED. The RED value was increased by approximately 15% by using UVCalc3D fluence rate model. Additionally, the asymmetric lamp positioning of the UV lamps had more than 50% of the pathogens received a better and a higher UV dose than in the symmetric case. Consequently, the system dose performance was improved by asymmetric lamp positioning. It was concluded that the performance parameters (higher RED and system dose performance were improved by using asymmetric lamp positioning.

  16. Removal of sulfamethoxazole, ibuprofen and nitrobenzene by UV and UV/chlorine processes: A comparative evaluation of 275 nm LED-UV and 254 nm LP-UV.

    Science.gov (United States)

    Kwon, Minhwan; Yoon, Yeojoon; Kim, Seonbaek; Jung, Youmi; Hwang, Tae-Mun; Kang, Joon-Wun

    2018-05-15

    The aim of this study is to evaluate the micropollutant removal capacity of a 275 nm light-emitting diode (LED)-UV/chlorine system. The sulfamethoxazole, ibuprofen, and nitrobenzene removal efficiencies of this system were compared with those of a conventional 254 nm low-pressure (LP)-UV system as a function of the UV dose. In a direct photolysis system, the photon reactivity of sulfamethoxazole is higher than that of nitrobenzene and ibuprofen at both wavelengths. The molar absorption coefficients and quantum yields of each micropollutant were as follows: sulfamethoxazole (ε SMX, 275 nm protonated  = 17,527 M -1  cm -1 , Φ SMX, 275 nm protonated  = 0.239, ε SMX, 275 nm deprotonated  = 8430 M -1  cm -1 , and Φ SMX, 275 nm deprotonated  = 0.026), nitrobenzene (ε NB, 275 nm  = 7176 M -1  cm -1 and Φ NB, 275 nm  = 0.057), and ibuprofen (ε NB, 275 nm  = 200 M -1  cm -1 and Φ IBF, 275 nm  = 0.067). The photon reactivity of chlorine species, i.e., HOCl and OCl-, were determined at 275 nm (ε HOCl, 275 nm  = 28 M -1  cm -1 , Φ HOCl, 275 nm  = 1.97, ε OCl-, 275 nm  = 245 M -1  cm -1 , and Φ OCl-, 275 nm  = 0.8), which indicate that the decomposition rate of OCl - is higher and that of HOCl is lower by 275 nm photolysis than that by 254 nm photolysis (ε HOCl, 254 nm  = 60 M -1  cm -1 , Φ HOCl, 254 nm  = 1.46, ε OCl-, 254 nm  = 58 M -1  cm -1 , and Φ OCl-, 254 nm  = 1.11). In the UV/chlorine system, the removal rates of ibuprofen and nitrobenzene were increased by the formation of OH and reactive chlorine species. The 275-nm LED-UV/chlorine system has higher radical yields at pH 7 and 8 than the 254 nm LP-UV/chlorine system. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Alkali-developable silicone-based negative photoresist (SNP) for deep UV, electron beam, and X-ray lithographies

    International Nuclear Information System (INIS)

    Ban, Hiroshi; Tanaka, Akinobu; Kawai, Yoshio; Deguchi, Kimiyoshi

    1989-01-01

    A new silicone-based negative photoresist (SNP) developable with alkaline aqueous solutions is prepared. SNP composed of acetylated phenylsilsesquioxane oligomer and azidopyrene is applied to deep UV, electron beam (EB), and X-ray lithographies. SNP slightly swells in alkaline developers, thus exhibiting exceptionally high resolution characteristics for a negative resist. The resistance of SNP to oxygen reactive ion etching is approximately 30 times greater than that of conventional novolac resists. (author)

  18. Assessment of interplay between UV wavelengths, material surfaces and food residues in open surface hygiene validation

    DEFF Research Database (Denmark)

    Abban, Stephen; Jakobsen, Mogens; Jespersen, Lene

    2014-01-01

    The use of UV-visible radiation for detecting invisible residue on different surfaces as a means of validating cleanliness was investigated. Wavelengths at 365, 395, 435, 445, 470 and 490 nm from a monochromator were used to detect residues of beef, chicken, apple, mango and skim milk. These were....... It is important when UV-systems are used as real-time tools for assessing cleanliness of surfaces that the surface materials being illuminated are taken into account in the choice of lamp wavelength, in addition to expected residue. This will ensure higher confidence in results during the use of UV-light for real...

  19. Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview

    International Nuclear Information System (INIS)

    Rozema, Jelte; Boelen, Peter; Blokker, Peter

    2005-01-01

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. - Polar plant responses to UV-B may be different in the Arctic than Antarctic regions

  20. Effects of UV-B irradiation on photomovement in the desmid, Cosmarium cucumis

    International Nuclear Information System (INIS)

    Haeder, D.-P.

    1987-01-01

    Monochromatic UV-B irradiation affects neither the absorption nor the fluorescence of the bulk pigments in the desmid Cosmarium cucumis but it impairs photomovement of these organisms at fluence rates which are not higher than the ambient level of solar UV-B irradiation. Photoaccumulations and phototaxis are strongly inhibited especially at wavelengths <= 300 nm while photodispersal at higher white light fluence rates is hardly affected by supplementary UV-B. This effect has important consequences for the growth and survival of populations in their natural environment: these photosynthetic organisms utilize photomovement to find and stay in areas of suitable visible light fluence rates. The UV-B component of solar irradiation both impairs the strategy of the organisms to find a suitable position and the escape mechanism by which the cells move out of areas with too strong white illuminances which photooxidize the bulk pigments and bleach the population within a few days. (author)

  1. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K; Leszczynski, K; Visuri, R; Ylianttila, L [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1996-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  2. UV dichroic coatings on metallic reflectors

    International Nuclear Information System (INIS)

    Raghunath, C; Babu, N J; Chandran, K M

    2008-01-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail

  3. UV dichroic coatings on metallic reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Raghunath, C; Babu, N J; Chandran, K M [Hind High Vacuum Co. Pvt. Ltd. No.17, Phase 1, Peenya Industrial Area, Bangalore 560058 (India)

    2008-05-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail.

  4. UV Bandpass Optical Filter for Microspectometers

    NARCIS (Netherlands)

    Correia, J.H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in

  5. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  6. Discontinuities during UV writing of waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour.......UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour....

  7. Direct UV-writing of waveguides

    DEFF Research Database (Denmark)

    Færch, Kjartan Ullitz

    2003-01-01

    induced refractive index change of more than 10-2 have been obtained. New insight, with respect to understanding the UV induced index change obtained by direct UV writing, has been provided, through experiments conducted with such high-pressure loaded germanosilica samples. This include measurements...

  8. Effect of UV laser irradiation on tissue

    International Nuclear Information System (INIS)

    Nakayama, Takeyoshi; Kubo, Uichi

    1992-01-01

    Laser-tissue interactions have been investigated through Electron Probe Micro Analysis (EPMA), UV-visible optical absorption and Fourier Transform Infrared Spectroscopy (FTIR). Three excimer lasers, ArF, KrF and XeCl, were used to irradiate tissue; cow thighbone and gelatin thin film. Features of UV laser irradiation are described. (author)

  9. uv photobiology: DNA damage and repair

    International Nuclear Information System (INIS)

    Sutherland, B.M.

    1978-01-01

    The following topics are discussed: targets that determine the fate of the cell when uv light interacts with a cell; comparison of action spectrum for a given biological effect with the absorption spectrum of different biological macromolecules; biological effects of damage to DNA; measurement of mutations; chemical damage to DNA; photoreactivation; role of pyrimidine dimers in induction of skin cancer by uv

  10. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  11. UV Reconstruction Algorithm And Diurnal Cycle Variability

    Science.gov (United States)

    Curylo, Aleksander; Litynska, Zenobia; Krzyscin, Janusz; Bogdanska, Barbara

    2009-03-01

    UV reconstruction is a method of estimation of surface UV with the use of available actinometrical and aerological measurements. UV reconstruction is necessary for the study of long-term UV change. A typical series of UV measurements is not longer than 15 years, which is too short for trend estimation. The essential problem in the reconstruction algorithm is the good parameterization of clouds. In our previous algorithm we used an empirical relation between Cloud Modification Factor (CMF) in global radiation and CMF in UV. The CMF is defined as the ratio between measured and modelled irradiances. Clear sky irradiance was calculated with a solar radiative transfer model. In the proposed algorithm, the time variability of global radiation during the diurnal cycle is used as an additional source of information. For elaborating an improved reconstruction algorithm relevant data from Legionowo [52.4 N, 21.0 E, 96 m a.s.l], Poland were collected with the following instruments: NILU-UV multi channel radiometer, Kipp&Zonen pyranometer, radiosonde profiles of ozone, humidity and temperature. The proposed algorithm has been used for reconstruction of UV at four Polish sites: Mikolajki, Kolobrzeg, Warszawa-Bielany and Zakopane since the early 1960s. Krzyscin's reconstruction of total ozone has been used in the calculations.

  12. Fabrication of silver nanowires and metal oxide composite transparent electrodes and their application in UV light-emitting diodes

    Science.gov (United States)

    Yan, Xingzhen; Ma, Jiangang; Xu, Haiyang; Wang, Chunliang; Liu, Yichun

    2016-08-01

    In this paper, we prepared the silver nanowires (AgNWs)/aluminum-doped zinc oxide (AZO) composite transparent conducting electrodes for n-ZnO/p-GaN heterojunction light emitting-diodes (LEDs) by drop casting AgNW networks and subsequent atomic layer deposition (ALD) of AZO at 150 °C. The contact resistances between AgNWs were dramatically reduced by pre-annealing in the vacuum chamber before the ALD of AZO. In this case, AZO works not only as the conformal passivation layer that protects AgNWs from oxidation, but also as the binding material that improves AgNWs adhesion to substrates. Due to the localized surface plasmons (LSPs) of the AgNWs resonant coupling with the ultraviolet (UV) light emission from the LEDs, a higher UV light extracting efficiency is achieved from LEDs with the AgNWs/AZO composite electrodes in comparison with the conventional AZO electrodes. Additionally, the antireflective nature of random AgNW networks in the composite electrodes caused a broad output light angular distribution, which could be of benefit to certain optoelectronic devices like LEDs and solar cells.

  13. Bacterial Survival under Extreme UV Radiation: A Comparative Proteomics Study of Rhodobacter sp., Isolated from High Altitude Wetlands in Chile

    Directory of Open Access Journals (Sweden)

    Vilma Pérez

    2017-06-01

    Full Text Available Salar de Huasco, defined as a polyextreme environment, is a high altitude saline wetland in the Chilean Altiplano (3800 m.a.s.l., permanently exposed to the highest solar radiation doses registered in the world. We present here the first comparative proteomics study of a photoheterotrophic bacterium, Rhodobacter sp., isolated from this remote and hostile habitat. We developed an innovative experimental approach using different sources of radiation (in situ sunlight and UVB lamps, cut-off filters (Mylar, Lee filters and a high-throughput, label-free quantitative proteomics method to comprehensively analyze the effect of seven spectral bands on protein regulation. A hierarchical cluster analysis of 40 common proteins revealed that all conditions containing the most damaging UVB radiation induced similar pattern of protein regulation compared with UVA and visible light spectral bands. Moreover, it appeared that the cellular adaptation of Rhodobacter sp. to osmotic stress encountered in the hypersaline environment from which it was originally isolated, might further a higher resistance to damaging UV radiation. Indeed, proteins involved in the synthesis and transport of key osmoprotectants, such as glycine betaine and inositol, were found in very high abundance under UV radiation compared to the dark control, suggesting the function of osmolytes as efficient reactive oxygen scavengers. Our study also revealed a RecA-independent response and a tightly regulated network of protein quality control involving proteases and chaperones to selectively degrade misfolded and/or damaged proteins.

  14. The Photocatalytic Activity of TiO2-Zeolite Composite for Degradation of Dye Using Synthetic UV and Jeddah Sunlight

    Directory of Open Access Journals (Sweden)

    Laila M. Al-Harbi

    2015-01-01

    Full Text Available In this research different composites of impregnated TiO2 with LTA or FAU zeolites were used as different weight% ratio for photodegradation of organic dye. Normal laboratory UV-lamps were used as a source of UV irradiation. In addition a setup of system of mirrors was used to collect real Jeddah sunlight. A comparison of UV and real sunlight photodegradation activity showed that the real sunlight enhances new centers of active sites exhibiting higher catalytic activity than that of UV irradiated samples.

  15. Mutation induction in haploid yeast after split-dose radiation-exposure. I. Fractionated UV-irradiation.

    Science.gov (United States)

    Schenk, K; Zölzer, F; Kiefer, J

    1989-01-01

    Mutation induction was investigated in wild-type haploid yeast Saccharomyces cerevisiae after split-dose UV-irradiation. Cells were exposed to fractionated 254 nm-UV-doses separated by intervals from 0 to 6 h with incubation either on non-nutrient or nutrient agar between. The test parameter was resistance to canavanine. If modifications of sensitivity due to incubation are appropriately taken into account there is no change of mutation frequency.

  16. Effects of ultraviolet-B radiation (UV-B) on growth and physiology of the dune grassland species Calamagrostis epigeios

    International Nuclear Information System (INIS)

    Tosserams, M.; Rozema, J.

    1995-01-01

    Seedlings of Calamagrostis epigeios were exposed to four levels of UV-B radiation (280-320 nm), simulating up to 44% reduction of stratospheric ozone concentration during summertime in The Netherlands, to determine the response of this plant species to UV-B irradiation. After six weeks of UV-B treatment, total biomass of all UV-B treated plants was higher, compared to plants that had received no UV-B radiation. The increase of biomass did not appear to be the result of a stimulation of net photosynthesis. Also, transpiration rate and water use efficiency were not altered by UV-B at any exposure level. Pigment analysis of leaf extracts showed no effect of enhanced UV-B radiation on chlorophyll content and accumulation of UV absorbing pigments. UV-B irradiance, however, did reduce the transmittance of visible light (400-700 nm) of intact attached leaves, suggesting a change in anatomical characteristics of the leaves. Additionally, the importance of including an ambient UV-B treatment in indoor experiments is discussed

  17. [ASSOCIATION OF SKIN PHOTOTYPE AND UV EXPOSURE WITH EXPRESSION OF

    Science.gov (United States)

    Drvar, D Ledić; Lipozenčić, J; Mokos, Z Bukvić; Ilić, I; Knežević, F

    2015-01-01

    included non-parametrical statistical methods and statistical reviews. Analysis was done using R statistical package. Statistical significance was set at pskin phototypes (according to Fitzpatrick) were present in our study: 54 (53.47%) patients with phototype II and 47 (46.53%) patients with phototype III. The majority of patients (n=93; 92.08%) were exposed to increased UV radiation during lifetime. Forty (39.60%) patients had three or more sunburns during childhood. Study results showed a signifi cantly higher expression of EGFR receptors, Ki67 and protein p53 in patients with light skin phototype that had been exposed to increased UV light during lifetime or had acquired 3 or more sunburns in childhood, suggesting that UV exposure led to the induction of EGFR, Ki67 and protein p53, and consequently to development of cSCC.

  18. UV-straling in de kas: mogelijkheden en grenzen

    NARCIS (Netherlands)

    Hoffmann, S.

    2000-01-01

    Effect van UV-straling op kleuring van Coleus Blumei 'Wizzard Velvit Red'. Gegevens in bijgaande tabellen: 1) Indeling optische straling; 2) Transmisse voor UV-straling van verschillende dekmaterialen (folie UV, glas UV, glas normaal, folie normaal, folie UV-blok

  19. Ultraviolet radiation exposure from UV-transilluminators.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Jahangir-Blourchian, Mahdi

    2005-10-01

    UV-transilluminators use ultraviolet radiation (UVR) to visualize proteins, DNA, RNA, and their precursors in a gel electrophoresis procedure. This study was initiated to evaluate workers' exposure to UVR during their use of UV-transilluminators. The levels of irradiance of UV-A, UV-B, and UV-C were determined for 29 UV-transilluminators at arbitrary measuring locations of 6, 25, 62, and 125 cm from the center of the UV-transilluminator's filter surface in the direction of the operator's head. The operators (faculty, research staff, and graduate students) worked within 62 cm of the transilluminators, with most subjects commonly working at time ranged from 1 to 60 min. Actinic hazard (effective irradiance level of UVR) was also determined for three representative UV-transilluminators at arbitrary measuring locations of 2.5, 5, 10, 15, 20, 30, 40, and 50 cm from these sets' filter surface in the direction of the operator's head. The allowable exposure time for these instruments was less than 20 sec within 15 cm, less than 35 sec within 25 cm, and less than 2 min within 50 cm from the UV-transilluminators' filter surface. The results of this study suggest that the use of UV-transilluminators exposes operators to levels of UVR in excess of exposure guidelines. It is recommended that special safety training be provided for the affected employees and that exposure should be controlled by one or the combination of automation, substitution, isolation, posted warning signs, shielding, and/or personal protective equipment.

  20. Effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme in bean (Phaseolus vulgaris L.) grown under different nitrogen conditions.

    Science.gov (United States)

    Pinto, M E; Casati, P; Hsu, T P; Ku, M S; Edwards, G E

    1999-02-01

    The effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme have been examined in different cultivars of Phaseolous vulgaris L. grown under 1 and 12 mM nitrogen. Low nitrogen nutrition reduces chlorophyll and soluble protein contents in the leaves and thus the photosynthesis rate and dry-matter accumulation. Chlorophyll, soluble protein and Rubisco contents and photosynthesis rate are not significantly altered by ambient levels of UV-B radiation (17 microW m-2, 290-320 nm, 4 h/day for one week). Comparative studies show that under high nitrogen, UV-B radiation slightly enhances leaf expansion and dry-matter accumulation in cultivar Pinto, but inhibits these parameters in Vilmorin. These results suggest that the UV-B effect on growth is mediated through leaf expansion, which is particularly sensitive to UV-B, and that Pinto is more tolerant than Vilmorin. The effect of UV-B radiation on UV-B-absorbing compounds and on NADP-malic enzyme (NADP-ME) activity is also examined. Both UV-B radiation and low-nitrogen nutrition enhance the content of UV-B-absorbing compounds, and among the three cultivars used, Pinto exhibits the highest increases and Arroz the lowest. The same trend is observed for the specific activity and content of NADP-ME. On a leaf-area basis, the amount of UV-B-absorbing compounds is highly correlated with the enzyme activity (r2 = 0.83), suggesting that NADP-ME plays a key role in biosynthesis of these compounds. Furthermore, the higher sensitivity of Vilmorin than Pinto to UV-B radiation appears to be related to the activity of NADP-ME and the capacity of the plants to accumulate UV-B-absorbing compounds.

  1. Plant responses to UV-B irradiation are modified by UV-A irradiation

    International Nuclear Information System (INIS)

    Middleton, E.M.; Teramura, A.H.

    1993-01-01

    The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

  2. Resist materials for proton micromachining

    International Nuclear Information System (INIS)

    Kan, J.A. van; Sanchez, J.L.; Xu, B.; Osipowicz, T.; Watt, F.

    1999-01-01

    The production of high aspect ratio microstructures is a potential growth area. The combination of deep X-ray lithography with electroforming and micromolding (i.e. LIGA) is one of the main techniques used to produce 3D microstructures. The new technique of proton micromachining employs focused MeV protons in a direct write process which is complementary to LIGA, e.g. micromachining with 2 MeV protons results in microstructures with a height of 63 μm and lateral sub-micrometer resolution in PMMA resist. The aim of this paper is to investigate the capabilities of proton micromachining as a lithographic technique. This involves the study of different types of resists. The dose distribution of high molecular weight PMMA is compared with three other types of resist: First the positive photo resist AZ P4620 will be discussed and then PMGI SF 23, which can be used as a deep UV, e-beam or X-ray resist. Finally SU-8, a new deep UV negative type of chemically amplified resist will be discussed. All these polymers are applied using the spin coating technique at thicknesses of between 1 and 36 μm

  3. Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

    Science.gov (United States)

    Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

    2018-03-01

    Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

  4. Comparison of UV irradiation and p-fluorphenylaline as selective agents for production of aromatic compounds in plant cell culture

    International Nuclear Information System (INIS)

    Quesnel, A.A.; Ellis, B.E.

    1989-01-01

    Resistance to UV irradiation, and to the toxicity of p-fluorophenylalanine, can both be mediateted in plants by enhanced synthesis of aromatic compounds. These selective agents were applied to cell cultures of Nicotiana tabacum, Anchusa officinalis and Catharanthus roseur, and the production of aromatic metabolites in the resulting resistant lines of each species was compared. While Nicotiana and Anchusa cultures responded to each selective agent ith an enhanced accumulation of aromatic compounds, the Catharanthus cultures acquired resistance through other, unknown, mechanisms. Some degree of cross-resistance was observed between cultures selected individually for resistance to each agent (author). 26 refs.; 2 figs.; 1 tab

  5. Effect of UV-C irradiation on growth, sporulation and pathogenicity of cochliobolus sativus isolates

    International Nuclear Information System (INIS)

    Jawhar, M.; Arabi, M.I.E.

    1999-12-01

    More than 30 isolates of Cochliobolus sativus, the causal agent of common root rot disease; were collected from different regions of Syria. Seven of them were exposed to UV-C light for 40 or 60 h . at a dose rate of 2.52x10 -3 W/cm 2 . A significant increases in the mycelium growth and sporulation were detected (p<0.001). Within the studied range of UV wave length, these two parameters were increased upon increasing the period of exposure to UV-C light. The pathogenicity of four isolates was evaluated after 60 h. of UV irradiation. The response to UV irradiation varied among these isolates, and resulted in an increase in their virulence level (as assessed by evaluating disease severity on sub-crown internodes). Five barley genotypes possessing different levels of resistance to C. sativus were studied. Arabi Abiad was the most susceptible cultivar whereas, Taka 76 line was moderately susceptible. It is concluded that it is possible to implement the positive effect of low doses of UV-C in stimulating the sporulation of fungi, which are difficult to sporulate on artificial media. (author)

  6. Isolation of uv-sensitive variants of CHO-Kl by nylon cloth replicaplating

    International Nuclear Information System (INIS)

    Stamato, T.D.; Waldren, C.A.

    1977-01-01

    Techniques are described which permit the identification and isolation of uv-sensitive variants from mutagenized populations of Chinese hamster ovary (CHO) cells. Identification is based on the observation that within two days after receiving a dose of approximately 240 ergs/mm 2 of uv irradiation, most of the cells in a colony of CHO detach from the surface of a plastic tissue culture dish. At a lower dose of uv, which does not kill or detach a significant number of parental cells, uv-sensitive colonies are killed and become detached. Thus a clear plaque is produced in a lawn of unirradiated parental cells, marking the site occupied by a sensitive colony. Live cells from such sensitive colonies have been recovered from a nylon cloth replica prepared prior to irradiation and characterized. One uv-sensitive variant (CHO-UV-1) is indistinguishable from parental cells in x-ray resistance, chromosome number, generation time, and duration of the phases of the cell cycle

  7. Effect of UV irradiation on optical, mechanical and microstructural properties of PVA/NaAlg blends

    Science.gov (United States)

    Sheela, T.; Bhajantri, R. F.; Ravindrachary, V.; Rathod, Sunil G.; Pujari, P. K.; Poojary, Boja; Somashekar, R.

    2014-10-01

    Poly(vinyl alcohol) (PVA)/Sodium alginate (NaAlg) blend films with 60:40 wt% were prepared by solution casting method and subjected to UV irradiation for different intervals of time. The optical, mechanical and morphological properties of the blend films were modified after UV irradiation. The FTIR and FT-Raman results show the chemical interaction between PVA and NaAlg. The UV-vis absorption peak at 278 nm shifts slightly towards longer wavelength and the absorption increases with irradiation time, indicate the increase in crosslinking network. The XRD results show an increase in amorphous nature with increase in UV irradiation time. The DSC/TGA results show a single glass transition temperature (Tg), which confirm that the blends are completely miscible and thermally stable up to 250 °C. The Young's modulus, tensile strength and stiffness of the blend films increase with increase in UV irradiation time. The SEM images confirm that the surface of 48 h UV irradiated PVA:NaAlg blend is more photo-resistant than unirradiated blend.

  8. UV-C Adaptation of Shigella: Morphological, Outer Membrane Proteins, Secreted Proteins, and Lipopolysaccharides Effects.

    Science.gov (United States)

    Chourabi, Kalthoum; Campoy, Susana; Rodriguez, Jesus A; Kloula, Salma; Landoulsi, Ahmed; Chatti, Abdelwaheb

    2017-11-01

    Water UV disinfection remains extremely important, particularly in developing countries where drinking and reclaimed crop irrigation water may spread devastating infectious diseases. Enteric bacterial pathogens, among which Shigella, are possible contaminants of drinking and bathing water and foods. To study the effect of UV light on Shigella, four strains were exposed to different doses in a laboratory-made irradiation device, given that the ultraviolet radiation degree of inactivation is directly related to the UV dose applied to water. Our results showed that the UV-C rays are effective against all the tested Shigella strains. However, UV-C doses appeared as determinant factors for Shigella eradication. On the other hand, Shigella-survived strains changed their outer membrane protein profiles, secreted proteins, and lipopolysaccharides. Also, as shown by electron microscopy transmission, morphological alterations were manifested by an internal cytoplasm disorganized and membrane envelope breaks. Taken together, the focus of interest of our study is to know the adaptive mechanism of UV-C resistance of Shigella strains.

  9. Applications of derivative UV/VIS spectroscopy in water analysis

    International Nuclear Information System (INIS)

    Hellmann, H.

    1994-01-01

    Derivative UV/VIS spectra offer new possibilities in determination and identification of trace substances in waters, suspended matter, and in sediments. Aromatics and their derivatives, such as alkyl-benzene-sulfonates, esters of phthalic acid, alkyl-phenol-oxethylates etc., but also non-aromatic substances with a π-bond can be identified. Compounds showing no absorption in the UV/VIS range can be detected by adding a suitable corectant, e.g. cationic detergents by means of disulfin-blue of BiJ 4 - . Normally, a clean-up is necessary. The recommended procedure is two- or multi-stage chromatography on adsorbing layers of silica gel or aluminium oxide. Thus, numerous substances can be identified and quantified at levels as low as 5 microgram. In some cases, it will be useful to supplement the method by fluorescent spectra of higher orders. (orig.) [de

  10. The effect of inorganic precursors on disinfection byproduct formation during UV-chlorine/chloramine drinking water treatment.

    Science.gov (United States)

    Lyon, Bonnie A; Dotson, Aaron D; Linden, Karl G; Weinberg, Howard S

    2012-10-01

    Ultraviolet (UV) disinfection is being increasingly used in drinking water treatment. It is important to understand how its application to different types of water may influence finished water quality, particularly as anthropogenic activity continues to impact the quality of source waters. The objective of this study was to evaluate the effect of inorganic precursors on the formation of regulated and unregulated disinfection byproducts (DBPs) during UV irradiation of surface waters when combined with chlorination or chloramination. Samples were collected from three drinking water utilities supplied by source waters with varying organic and inorganic precursor content. The filtered samples were treated in the laboratory with a range of UV doses delivered from low pressure (LP, UV output at 253.7 nm) and medium pressure (MP, polychromatic UV output 200-400 nm) mercury lamps followed by chlorination or chloramination, in the presence and absence of additional bromide and nitrate. The regulated trihalomethanes and haloacetic acids were not affected by UV pretreatment at disinfection doses (40-186 mJ/cm²). With higher doses (1000 mJ/cm²), trihalomethane formation was increased 30-40%. While most effects on DBPs were only observed with doses much higher than typically used for UV disinfection, there were some effects on unregulated DBPs at lower doses. In nitrate-spiked samples (1-10 mg N/L), chloropicrin formation doubled and increased three- to six-fold with 40 mJ/cm² MP UV followed by chloramination and chlorination, respectively. Bromopicrin formation was increased in samples containing bromide (0.5-1 mg/L) and nitrate (1-10 mg N/L) when pretreated with LP or MP UV (30-60% with 40 mJ/cm² LP UV and four- to ten-fold increase with 40 mJ/cm² MP UV, after subsequent chlorination). The formation of cyanogen chloride doubled and increased three-fold with MP UV doses of 186 and 1000 mJ/cm², respectively, when followed by chloramination in nitrate-spiked samples but

  11. Radioactive decontamination through UV laser

    International Nuclear Information System (INIS)

    Delaporte, Ph.; Gastaud, M.; Sentis, M.; Uteza, O.; Marine, W.; Thouvenot, P.; Alcaraz, J.L.; Le Samedy, J.M.; Blin, D.

    2003-01-01

    A device allowing the radioactive decontamination of metal surfaces through the use of a pulsed UV laser has been designed and tested. This device is composed of a 1 kW excimer laser linked to a bundle of optic fibers and of a system to recover particles and can operate in active zones. Metal surfaces have the peculiarities to trap radio-elements in a superficial layer of oxide that can be eaten away by laser radiation. Different contaminated metals (stainless steels, INCONEL and aluminium) issued from the nuclear industry have been used for the testing. The most important contaminants were 60 Co, 137 Cs, 154-155 Eu and 125 Sb. The ratio of decontamination was generally of 10 and the volume of secondary wastes generating during the process was very low compared with other decontamination techniques. A decontamination speed of 1 m 2 /h has been reached for aluminium. The state of the surface is an important parameter because radio-elements trapped in micro-cracks are very difficult to remove. (A.C.)

  12. Long-term effects of elevated UV-B radiation on photosynthesis and ultrastructure of Eriophorum russeolum and Warnstorfia exannulata

    International Nuclear Information System (INIS)

    Haapala, Jaana K.; Moersky, Sami K.; Saarnio, Sanna; Suokanerva, Hanne; Kyroe, Esko; Silvola, Jouko; Holopainen, Toini

    2010-01-01

    The depletion of stratospheric ozone above the Arctic regions may increase the amount of UV-B radiation to which the northern ecosystems are exposed. In this paper, we examine the hypothesis that supplemental UV-B radiation may affect the growth rate and photosynthesis of boreal peatland plants and could thereby affect the carbon uptake of these ecosystems. In this study, we report the effects of 3-year exposure to elevated UV-B radiation (46% above ambient) on the photosynthetic performance and ultrastructure of a boreal sedge Eriophorum russeolum and a moss Warnstorfia exannulata. The experiment was conducted on a natural fen ecosystem at Sodankylae in northern Finland. The effects of UV-B radiation on the light response of E. russeolum CO 2 assimilation and the maximal photochemical efficiency of photosystem II in a dark-adapted state (F v /F m ) were measured in the field. In addition, the effect of supplemental UV-B radiation on organelles of photosynthetic cells was studied by electron microscopy. The UV-B treatment had no effect on the CO 2 assimilation rate of either species, nor did it affect the structure of the cell organelles. On chlorophyll fluorescence, the UV-B exposure had only a temporary effect during the third exposure year. Our results suggested that in a natural ecosystem, even long-term exposure to reasonably elevated UV-B radiation levels does not affect the photosynthesis of peatland plants. - Research highlights: →Eriophorum russeolum and Warnstorfia exannulata are resistant to UV-B radiation →UV-B exposure does not affect the growth or photosynthesis of E. russeolum →Long-term UV-B exposure has no effect on the ultrastructure of E. russeolum

  13. Post-UV colony-forming ability of normal fibroblast strains and of the xeroderma pigmentosum group G strain

    International Nuclear Information System (INIS)

    Barrett, S.F.; Tarone, R.E.; Moshell, A.N.; Ganges, M.B.; Robbins, J.H.

    1981-01-01

    In xeroderma pigmentosum, an inherited disorder of defective DNA repair, post-uv colony-forming ability of fibroblasts from patients in complementation groups A through F correlates with the patients' neurological status. The first xeroderma pigmentosum patient assigned to the recently discovered group G had the neurological abnormalities of XP. Researchers have determined the post-uv colony-forming ability of cultured fibroblasts from this patient and from 5 more control donors. Log-phase fibroblasts were irradiated with 254 nm uv light from a germicidal lamp, trypsinized, and replated at known densities. After 2 to 4 weeks' incubation the cells were fixed, stained and scored for colony formation. The strains' post-uv colony-forming ability curves were obtained by plotting the log of the percent remaining post-uv colony-forming ability as a function of the uv dose. The post-uv colony-forming ability of 2 of the 5 new normal strains was in the previously defined control donor zone, but that of the other 3 extended down to the level of the most resistant xeroderma pigmentosum strain. The post-uv colony-forming ability curve of the group G fibroblasts was not significantly different from the curves of the group D fibroblast strains from patients with clinical histories similar to that of the group G patient

  14. Enhancement of UV absorption behavior in Zn O-TiO2 composites

    International Nuclear Information System (INIS)

    Jimenez Reinosa, J.; Leret, P.; Alvarez-Docio, C. M.; Campo, A. del; Fernandez, J. F.

    2016-01-01

    The ultraviolet -visible, UV-vis, absorption edge behaviour of semiconductor oxides as TiO 2 and ZnO promotes their use as inorganic UV filters for sunscreens. In cosmetics, the use of nanoparticles is favoured because of their higher yield and lower whiteness. However, the particle size effect in the UV absorption is unclear. For this reason, the performances of nano and microsized TiO 2 and ZnO are evaluated in both the UV-vis spectroscopy and the Sun Protection Factor, SPF, value. In order to cover the UV range completely by using inorganic filters a new composite is attempted by dry nano dispersion methodology in which TiO 2 nanoparticles are dispersed onto ZnO microparticles. The new composite shows superior UV absorbing properties and ca. 60% SPF value due to a synergism between components that resulted in extended UV coverage and reduction of the total amount of nanoparticles required in the sunscreens. In addition, nanoparticles are effectively anchored onto microparticles avoiding the presence of free nanoparticles. (Author)

  15. Occurrence of organic UV filters and metabolites in lebranche mullet (Mugil liza) from Brazil.

    Science.gov (United States)

    Molins-Delgado, Daniel; Muñoz, Ramón; Nogueira, Sylvia; Alonso, Mariana B; Torres, João Paulo; Malm, Olaf; Ziolli, Roberta Lourenço; Hauser-Davis, Rachel Ann; Eljarrat, Ethel; Barceló, Damià; Díaz-Cruz, M Silvia

    2018-03-15

    UV filters (UV-Fs) constitute a heterogeneous group of chemicals used as protection against the effects of UV radiation, widely used in all sort of goods and ubiquitous in the environment. The presence of these chemicals in fish is a matter of concern, because many UV-Fs display hormonal activity. In this study, muscle, gills, and liver from 11 Mugil liza individuals from the highly urbanized Guanabara Bay (Rio de Janeiro, Brazil) were analysed in order to detect eight UV-Fs and metabolites (4-dihydroxybenzophenone [BP1] (2-hydroxy-4-methoxybenzophenone [BP3], 4-methylbenzylidiene camphor [4MBC], ethylhexyl methoxycinnamate [EHMC], ethylhexyl dimethyl p-aminobenzoic acid [ODPABA], octocrylene [OC], 4-hydroxybenzophenone [4HB], and 4,4'-dihydroxybenzophenone [4DHB]) using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results showed that both target UV-Fs and metabolites were ubiquitous in the analysed tissues. Lower concentrations were observed in muscle and gills (3.07-31.6ngg -1 dry weight (dw)), whereas in liver significant amounts of metabolites (5.47-451ngg -1 dw) were present. With the concentrations determined in the fish, an estimation of the daily intake revealed that consumption of muscle in the diet represent from 0.3 to 15.2ng UV-Fs (kg body weight -1 ) d -1 , higher than those reported in fish for selected persistent organic pollutants (POPs). Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A method for evaluation of UV and biologically effective exposures to plants

    International Nuclear Information System (INIS)

    Paris, A.V.; Southern Queensland Univ., Toowoomba, QLD; Wong, J.C.F.; Galea, V.

    1996-01-01

    This paper presents a method for evaluating the UV and biologically effective exposures to a plant canopy during the irradiation of soybean with supplemental levels of UV radiation in a greenhouse study. The method employs four materials as dosimeters that allow evaluation of the UV spectra. The exposures evaluated at three growth stages were less by factors of 0.44, 0.49 and 0.56 compared to the ambient exposures. At the end of the irradiation period, the ambient biologically effective exposure for generalized plant response was higher by 180% compared to that calculated over the canopy. This is the magnitude of the error in UV studies that provide the ambient exposure as a measure of the UV incident on the plant. Additionally, the difference between the ambient and canopy exposures varied during the growth stages. These results indicate that the dosimetric technique applied to evaluating the UV exposures over a plant canopy is a more accurate representation of the UV exposure incidence on a plant than any obtained by measuring the ambient exposures only. (Author)

  17. Enhancement of UV absorption behavior in Zn O-TiO{sub 2} composites

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Reinosa, J.; Leret, P.; Alvarez-Docio, C. M.; Campo, A. del; Fernandez, J. F.

    2016-05-01

    The ultraviolet -visible, UV-vis, absorption edge behaviour of semiconductor oxides as TiO{sub 2} and ZnO promotes their use as inorganic UV filters for sunscreens. In cosmetics, the use of nanoparticles is favoured because of their higher yield and lower whiteness. However, the particle size effect in the UV absorption is unclear. For this reason, the performances of nano and microsized TiO{sub 2} and ZnO are evaluated in both the UV-vis spectroscopy and the Sun Protection Factor, SPF, value. In order to cover the UV range completely by using inorganic filters a new composite is attempted by dry nano dispersion methodology in which TiO{sub 2} nanoparticles are dispersed onto ZnO microparticles. The new composite shows superior UV absorbing properties and ca. 60% SPF value due to a synergism between components that resulted in extended UV coverage and reduction of the total amount of nanoparticles required in the sunscreens. In addition, nanoparticles are effectively anchored onto microparticles avoiding the presence of free nanoparticles. (Author)

  18. Application of UV Imaging in Formulation Development

    DEFF Research Database (Denmark)

    Sun, Yu; Østergaard, Jesper

    2017-01-01

    defining formulation behavior after exposure to the aqueous environments and pharmaceutical performance is critical in pharmaceutical development, manufacturing and quality control of drugs. UV imaging has been explored as a tool for qualitative and quantitative characterization of drug dissolution...... related to the structural properties of the drug substance or formulation can be monitored. UV imaging is a non-intrusive and simple-to-operate analytical technique which holds potential for providing a mechanistic foundation for formulation development. This review aims to cover applications of UV...

  19. Global Solar UV Index (invited paper)

    International Nuclear Information System (INIS)

    Repacholi, M.H.

    2000-01-01

    Excessive solar ultraviolet (UV) radiation exposure produces a significant burden of disease to the skin, eyes and immune system. Effective programmes for the reduction of UV exposure are needed to reduce this disease burden and the associated health care costs. The UV index is seen as an effective tool for communicating important protection information to the public through its use in media news and weather information. The index is described and it is suggested that universally common messages should be associated with its ranges. (author)

  20. RPC industries - UV and EB equipment manufacturers

    International Nuclear Information System (INIS)

    Rodrigues, A.M.

    1987-01-01

    RPC Industries has been manufacturing electron beam and ultraviolet equipment for the industrial processing of materials for more than 15 years. RPC maintains its headquarters and electron processor manufacturing plant in Hayward, California. UV equipment is made in the company's plant near Chicago. Sales offices are maintained in New York, Illinois, and California in the USA, and in Germany, Japan, Australia, Italy, Israel, and Sweden. Complete testing and pilot facilities are available in Hayward (EB) and near Chicago (UV). Described below are the basic system components, applications and advantages of RPC's UV and EB systems. (orig.)

  1. Transformation of UV-hypersensitive Chinese hamster ovary cell mutants with UV-irradiated plasmids

    International Nuclear Information System (INIS)

    Nairn, R.S.; Humphrey, R.M.; Adair, G.M.

    1988-01-01

    Transfection of UV-hypersensitive, DNA repair-deficient Chinese hamster ovary (CHO) cell lines and parental, repair-proficient CHO cells with UV-irradiated pHaprt-1 or pSV2gpt plasmids resulted in different responses by recipient cell lines to UV damage in transfected DNA. Unlike results reported for human cells, UV irradiation of transfecting DNA did not stimulate genetic transformation of CHO recipient cells. In repair-deficient CHO cells, proportionally fewer transformants were produced with increasing UV damage than in repair-proficient cells in transfections with UV-irradiated hamster adenine phosphoribosyltransferase (APRT) gene contained in plasmid pHaprt-1. Transfection of CHO cells with UV-irradiated pSV2gpt resulted in neither decline in transformation frequencies in repair-deficient cell lines relative to repair-proficient cells nor stimulation of genetic transformation by UV damage in the plasmid. Blot hybridization analysis of DNA samples isolated from transformed cells showed no dramatic changes in copy number or arrangement of transfected plasmid DNA with increasing UV dose. The authors conclude responses of recipient cells to UV-damaged transfecting plasmids depend on type of recipient cell and characteristic