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Sample records for sv40 uv radiation

  1. SV40 DNA amplification and reintegration in surviving hamster cells after 60Co gamma-irradiation.

    Science.gov (United States)

    Lücke-Huhle, C; Pech, M; Herrlich, P

    1990-10-01

    SV40-transformed Chinese hamster embryo cells were exposed to 60Co gamma-irradiation and the fate of the integrated SV40 sequences was pursued over a period of 20 days following radiation exposure. As shown by colony hybridization, integrated SV40 sequences were amplified in surviving and non-surviving cells. At later times, however, clonal sublines of surviving cells grown for 20-30 cell generations after irradiation had lost most of their amplified SV40 copies but showed altered restriction fragment patterns indicating reintegration of SV40 sequences at new sites of the hamster genome. This suggests that 60Co gamma-irradiation can generate mutations by inducing over-replication of chromosome segments that are then substrates of enzymatic rearrangements.

  2. Columnar structure of SV40 minichromosome

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    Edward N Trifonov

    2015-07-01

    Full Text Available Like the sequence of the strongest 601 clone nucleosome of Lowary and Widom, the SV40 genome sequence contains tracks of YR dinucleotides separated by small integers of the 10.4n base series (10, 11, 21 and 30 bases. The tracks, however, substantially exceed the nucleosome DNA size and, thus, correspond to more extended structure - columnar chromatin. The micrococcal nuclease digests of the SV40 chromatin do not show uniquely positioned individual nucleosomes. This confirms the columnar structure of the minichromosome, as well as earlier electron microscopy studies.

  3. Transgenic Mouse Models of SV40-Induced Cancer.

    Science.gov (United States)

    Hudson, Amanda L; Colvin, Emily K

    2016-01-01

    The SV40 viral oncogene has been used since the 1970s as a reliable and reproducible method to generate transgenic mouse models. This seminal discovery has taught us an immense amount about how tumorigenesis occurs, and its success has led to the evolution of many mouse models of cancer. Despite the development of more modern and targeted approaches for developing genetically engineered mouse models of cancer, SV40-induced mouse models still remain frequently used today. This review discusses a number of cancer types in which SV40 mouse models of cancer have been developed and highlights their relevance and importance to preclinical research. © The Author 2016. Published by Oxford University Press on behalf of the Institute for Laboratory Animal Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  4. UV Radiation and the Skin

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    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.

  5. Sun, UV Radiation and Your Eyes

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    ... Eye Health / Tips & Prevention Your Eyes and the Sun Sections The Sun, UV Radiation and Your Eyes ... Best Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Leer en Español: ...

  6. Virus-specific nucleic acids in SV40-exposed hamster embryo cell lines: correlation with S and T antigens.

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    Levin, M J; Oxman, M N; Diamandopoulos, G T; Levine, A S; Henry, P H; Enders, J F

    1969-02-01

    A number of homologous SV40-exposed hamster embryonic cell lines were examined for the presence of RNA complementary to SV40 DNA. Only those lines containing the SV40 T antigen were found to have such virus-specific RNA. In lines containing the SV40 S antigen, but not the SV40 T antigen, virus-specific RNA was not detected. These findings suggest that the S antigen is not coded for directly by the SV40 genome.

  7. VIRUS-SPECIFIC NUCLEIC ACIDS IN SV40-EXPOSED HAMSTER EMBRYO CELL LINES: CORRELATION WITH S AND T ANTIGENS*

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    Levin, Myron J.; Oxman, Michael N.; Diamandopoulos, George Th.; Levine, Arthur S.; Henry, Patrick H.; Enders, John F.

    1969-01-01

    A number of homologous SV40-exposed hamster embryonic cell lines were examined for the presence of RNA complementary to SV40 DNA. Only those lines containing the SV40 T antigen were found to have such virus-specific RNA. In lines containing the SV40 S antigen, but not the SV40 T antigen, virus-specific RNA was not detected. These findings suggest that the S antigen is not coded for directly by the SV40 genome. PMID:4307716

  8. SV40 Assembly In Vivo and In Vitro

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    Ariella Oppenheim

    2008-01-01

    Full Text Available The Simian virus 40 (SV40 capsid is a T = 7d icosahedral lattice ∼45 nm in diameter surrounding the ∼5 kb circular minichromosome. The outer shell is composed of 360 monomers of the major capsid protein VP1, tightly bound in 72 pentamers. VP1 is a jellyroll β-barrel, with extending N- and C-terminal arms. The N-terminal arms bind DNA and face the interior of the capsid. The flexible C-arms tie together the 72 pentamers in three distinct kinds of interactions, thus facilitating the formation of a T = 7 icosahedron from identical pentameric building blocks. Assembly in vivo was shown to occur by addition of capsomers around the DNA. We apply a combination of biochemical and genetic approaches to study SV40 assembly. Our in vivo and in vitro studies suggest the following model: one or two capsomers bind at a high affinity to ses, the viral DNA encapsidation signal, forming the nucleation centre for assembly. Next, multiple capsomers attach concomitantly, at lower affinity, around the minichromosome. This increases their local concentration facilitating rapid, cooperative assembly reaction. Formation of the icosahedron proceeds either by gradual addition of single pentamers to the growing shell or by concerted assembly of pentamer clusters.

  9. Biologic properties of viable deletion mutants of simian virus 40 (SV40) rescued from the cells of an SV40-induced hamster lymphocytic leukemia.

    Science.gov (United States)

    Diamandopoulos, G T; Carmichael, G

    1983-12-01

    A lymphocytic leukemia induced by the oncogenic DNA simian virus 40 (SV40) in an inbred LSH/SsLak Syrian golden hamster was evoked to produce infectious SV40 by fusion of the leukemia cells with grivet monkey kidney (GMK) cells and by exposure of the leukemia cells to the chemical inducers mitomycin C and cycloheximide. Plaque-purified viable substrains of the rescued SV40 when studied by restriction endonuclease digestion of viral DNA were found to contain small deletions within the Hind III restriction fragment C. These deletions lay near the viral origin of DNA replication. Ten plaque-purified substrains of the rescued virus identified by immunofluorescence as being SV40 were found, when compared to the wild-type SV40, to replicate slowly and to form small plaques. Although these substrains transformed NIH/3T3 cells as efficiently as the wild-type SV40 in tissue culture, they were generally less oncogenic in vivo--7 of the 10 failed to induce tumors. The 3 oncogenic SV40-rescued substrains were not found to exhibit "lymphocytotropism," i.e., the capacity to infect and neoplastically transform preferentially hamster lymphocytes. Thus the hamster lymphocytic leukemia originally induced by the wild-type SV40 was most likely a chance-stochastic event rather than the result of tropism-determinism mediated by the virus, as is usually the case with leukemogenic RNA viruses.

  10. Polio vaccines, SV40 and human tumours, an update on false positive and false negative results.

    Science.gov (United States)

    Elmishad, A G; Bocchetta, M; Pass, H I; Carbone, M

    2006-01-01

    Simian virus 40 (SV40) has been detected in different human tumours in numerous laboratories. The detection of SV40 in human tumours has been linked to the administration of SV40-contaminated polio vaccines from 1954 until 1963. Many of these reports linked SV40 to human mesothelioma. Some studies have failed to detect SV40 in human tumours and this has caused a controversy. Here we review the current literature. Moreover, we present evidence showing how differences in the sensitivities of methodologies can lead to a very different interpretation of the same study. The same 20 mesothelioma specimens all tested negative, 2/20 tested positive or 7/20 tested positive for SV40 Tag by simply changing the detection method on the same immuno-precipitation/western blot membranes. These results provide a simple explanation for some of the apparent discordant results reported in the literature.

  11. Comparative transcriptome profiling of an SV40-transformed human fibroblast (MRC5CVI and its untransformed counterpart (MRC-5 in response to UVB irradiation.

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    Cheng-Wei Chang

    Full Text Available Simian virus 40 (SV40 transforms cells through the suppression of tumor-suppressive responses by large T and small t antigens; studies on the effects of these two oncoproteins have greatly improved our knowledge of tumorigenesis. Large T antigen promotes cellular transformation by binding and inactivating p53 and pRb tumor suppressor proteins. Previous studies have shown that not all of the tumor-suppressive responses were inactivated in SV40-transformed cells; however, the underlying cause is not fully studied. In this study, we investigated the UVB-responsive transcriptome of an SV40-transformed fibroblast (MRC5CVI and that of its untransformed counterpart (MRC-5. We found that, in response to UVB irradiation, MRC-5 and MRC5CVI commonly up-regulated the expression of oxidative phosphorylation genes. MRC-5 up-regulated the expressions of chromosome condensation, DNA repair, cell cycle arrest, and apoptotic genes, but MRC5CVI did not. Further cell death assays indicated that MRC5CVI was more sensitive than MRC-5 to UVB-induced cell death with increased caspase-3 activation; combining with the transcriptomic results suggested that MRC5CVI may undergo UVB-induced cell death through mechanisms other than transcriptional regulation. Our study provides a further understanding of the effects of SV40 transformation on cellular stress responses, and emphasizes the value of SV40-transformed cells in the researches of sensitizing neoplastic cells to radiations.

  12. Prevent Eye Damage: Protect Yourself from UV Radiation

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    PREVENT EYE DAMAGE Protect Yourself from UV Radiation M ost Americans understand the link between ultraviolet (UV) radiation and skin cancer. Many are less aware of the connection between UV radiation ...

  13. An investigation of the occurrence of sv40 antibodies in South Africa ...

    African Journals Online (AJOL)

    Four of the samples were from the healthy population group and the remaining 1 (1/64) was from the patient group. An SV40 antibody-blocking assay and a Western blot were used as additional confirmation for the SV40 antibodies, whereas the Western blot assay developed a single common band on all 5 samples.

  14. Fanconi anemia patients are more susceptible to infection with tumor virus SV40.

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    Manola Comar

    Full Text Available Fanconi anemia (FA is a recessive DNA repair disease characterized by a high predisposition to developing neoplasms. DNA tumor polyomavirus simian virus 40 (SV40 transforms FA fibroblasts at high efficiency suggesting that FA patients could be highly susceptible to SV40 infection. To test this hypothesis, the large tumor (LT antigen of SV40, BKV, JCV and Merkel Cell (MC polyomaviruses were tested in blood samples from 89 FA patients and from 82 of their parents. Two control groups consisting of 47 no-FA patients affected by other genetic bone marrow failure diseases and 91 healthy subjects were also evaluated. Although JCV, BKV and MC were not found in any of the FA samples, the prevalence and viral load of SV40 were higher in FA patients (25%; mean viral load: 1.1×10(2 copies/10(5cells as compared with healthy individuals (4.3%; mean viral load: 0.8×10(1 copies/10(5cells and genetic controls (0% (p<0.005. A marked age-dependent frequency of SV40 was found in FA with respect to healthy subjects suggesting that, although acquired early in life, the virus can widespread more easily in specific groups of population. From the analysis of family pedigrees, 60% of the parents of SV40-positive probands were positive for the virus compared to 2% of the parents of the SV40-negative probands (p<0.005. It is worthy of note that the relative frequency of SV40-positive relatives detected in this study was the highest ever reported, showing that asymptomatic FA carriers are also more susceptible to SV40. In conclusion, we favor the hypothesis that SV40 spread could be facilitated by individuals who are genetically more susceptible to infection, such as FA patients. The increased susceptibility to SV40 infection seems to be associated with a specific defect of the immune system which supports a potential interplay of SV40 with an underlying genetic alteration that increases the risk of malignancies.

  15. In vitro and in vivo Functional Characterization of Gutless Recombinant SV40-derived CFTR Vectors

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    Mueller, Christian; Strayer, Marlene S; Sirninger, Jeffery; Braag, Sofia; Branco, Francisco; Louboutin, Jean-Pierre; Flotte, Terence R.; Strayer, David S.

    2009-01-01

    In cystic fibrosis (CF) respiratory failure caused by progressive airway obstruction and tissue damage is primarily a result of the aberrant inflammatory responses to lung infections with Pseudomonas aeruginosa. Despite considerable improvement in patient survival, conventional therapies are mainly supportive. Recent progress towards gene therapy for CF has been encouraging; however, several factors such as immune response and transduced cell turnover remain as potential limitations to CF gene therapy. As alternative gene therapy vectors for CF we examined the feasibility of using SV40-derived vectors (rSV40s) which may circumvent some of these obstacles. To accommodate the large CFTR cDNA, we removed not only SV40 Tag genes, but also all capsid genes. We therefore tested whether “gutless” rSV40s could be packaged and were able to express a functional human CFTR cDNA. Results from our in vitro analysis determined that rSV40-CFTR was able to successfully result in the expression of CFTR protein which localized to the plasma membrane and restored channel function to CFTR deficient cells. Similarly in vivo experiments delivering rSV40-CFTR to the lungs of Cftr−/− mice resulted in a reduction of the pathology associated with intra-tracheal pseudomona aeruginosa challenge. rSV40-CFTR treated mice had had less weight loss when compared to control treated mice as well as demonstrably reduced lung inflammation as evidence by histology and reduced inflammatory cytokines in the BAL. The reduction in inflammatory cytokine levels led to an evident decrease in neutrophil influx to the airways. These results indicate that further study of the application of rSV40-CFTR to CF gene therapy is warranted. PMID:19890354

  16. Fatal SV40-associated pneumonia and nephropathy following renal allotransplantation in rhesus macaque.

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    Song, M; Mulvihill, M S; Williams, K D; Collins, B H; Kirk, A D

    2018-02-01

    Recrudescence of latent and dormant viruses may lead to overwhelming viremia in immunosuppressed hosts. In immunocompromised hosts, Simian virus 40 (SV40) reactivation is known to cause nephritis and demyelinating central nervous system disease. Here, we report SV40 viremia leading to fatal interstitial pneumonia in an immunosuppressed host following renal allotransplantation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Effects of UV radiation on phytoplankton

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    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. Temperature-sensitive SV40-immortalized rat middle ear epithelial cells.

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    Toyama, Katsuhiro; Kim, Youngki; Paparella, Michael M; Lin, Jizhen

    2004-12-01

    The proliferation and differentiation of middle ear epithelial cells are essential in both normal and diseased middle ears. The normal situation involves physiologic growth and renewal of the epithelium, and the diseased situation involves pathological changes of the epithelium such as mucous cell metaplasia and ciliated cell proliferation in otitis media. In this study, we used a temperature-sensitive large T antigen (the SV40 mutant) to transduce and immortalize the primary culture of middle ear epithelial cells. SV40-immortalized middle ear epithelial cells have been cultured for more than 50 passages and are stable morphologically. Their nonimmortalized parent cells died at the second passage. Immortalized middle ear epithelial cells carrying the SV40 mutant show a monolayer, cobblestonelike morphology. The cell line expresses characteristic middle ear mucosal molecules such as mucins, keratins, and collagens. It also responds to temperature changes; namely, cells proliferate at 33 degrees C, when the SV40 antigen is active, and differentiate at 39 degrees C, when the SV40 antigen is inactive. Therefore, we conclude that a temperature-sensitive middle ear epithelial cell line has successfully been established.

  19. UV-Radiation: From Physics to Impacts

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    Hanns Moshammer

    2017-02-01

    Full Text Available Ultraviolet (UV radiation has affected life at least since the first life forms moved out of the seas and crawled onto the land. Therefore, one might assume that evolution has adapted to natural UV radiation. However, evolution is mostly concerned with the propagation of the genetic code, not with a long, happy, and fulfilling life. Because rickets is bad for a woman giving birth, the beneficial effects of UV-radiation outweigh the adverse effects like aged skin and skin tumors of various grades of malignancy that usually only afflict us at older age. Anthropogenic damage to the stratospheric ozone layer and frighteningly high rates of melanoma skin cancer in the light-skinned descendants of British settlers in Australia piqued interest in the health impacts of UV radiation. A changing cultural perception of the beauty of tanned versus light skin and commercial interests in selling UV-emitting devices such as tanning booths caught public health experts off-guard. Counseling and health communication are extremely difficult when dealing with a “natural” risk factor, especially when this risk factor cannot (and should not be completely avoided. How much is too much for whom or for which skin type? How even measure “much”? Is it the (cumulative dose or the dose rate that matters most? Or should we even construct a more complex metric such as the cumulative dose above a certain dose rate threshold? We find there are still many open questions, and we are glad that this special issue offered us the opportunity to present many interesting aspects of this important topic.

  20. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

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    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.

  1. A very late viral protein triggers the lytic release of SV40.

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    Robert Daniels

    2007-07-01

    Full Text Available How nonenveloped viruses such as simian virus 40 (SV40 trigger the lytic release of their progeny is poorly understood. Here, we demonstrate that SV40 expresses a novel later protein termed VP4 that triggers the timely lytic release of its progeny. Like VP3, VP4 synthesis initiates from a downstream AUG start codon within the VP2 transcript and localizes to the nucleus. However, VP4 expression occurs approximately 24 h later at a time that coincides with cell lysis, and it is not incorporated into mature virions. Mutation of the VP4 initiation codon from the SV40 genome delayed lysis by 2 d and reduced infectious particle release. Furthermore, the co-expression of VP4 and VP3, but not their individual expression, recapitulated cell lysis in bacteria. Thus, SV40 regulates its life cycle by the later temporal expression of VP4, which results in cell lysis and enables the 50-nm virus to exit the cell. This study also demonstrates how viruses can generate multiple proteins with diverse functions and localizations from a single reading frame.

  2. [Determination of the need for solar UV radiation protection].

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    Letić, Milorad

    2010-01-01

    Effects of ultraviolet radiation on the skin, the eyes and the immune system are well known. The need for UV radiation protection is popularized by the introduction of UV index. Uneven intensity of UV radiation in different regions in different periods of the year and in different times of the day requires that recommendations for UV radiation protection are given for possible UV index values in those regions. The aim of the study is to establish a simple and consistent method for the determination of the need for UV radiation protection in Serbia where UV radiation intensity can be approximated as uniform. Possible values of UV index during the year and the sun elevation during the day in periods throughout the year were used for the determination of maximal possible UV index values. These values were compared to UV index forecasts regarding UV radiation protection. Maximal possible values for UV index were used for producing the colour graph. Colours on the graph indicate the need for UV radiation protection. Green--protection is not needed, yellow--protection is needed, red--protection is obligatory. Comparisons with the need for protection based on forecasts showed congruence in 97% of cases. The use of the graph for the determination of the need for UV radiation protection gives nearly the same results as recommendations based on UV index forecasts. The advantages of the graph are that it gives recommendations for the whole year, for the time intervals during the day in every period of the year and for the whole territory of Serbia.

  3. Life under solar UV radiation in aquatic organisms

    Science.gov (United States)

    Sinha, R. P.; Häder, D.-P.

    Aquatic photosynthetic organisms are exposed to solar ultraviolet (UV) radiation while they harvest longer wavelength radiation for energetic reasons. Solar UV-B radiation (280 - 315 nm) affects motility and orientation in motile organisms and impairs photosynthesis in cyanobacteria, phytoplankton and macroalgae as measured by monitoring oxygen production or pulse amplitude modulated fluorescence analysis. Upon moderate UV stress most organisms respond by photoinhibition which is an active downregulation of the photosynthetic electron transport in photosystem II by degradation of UV-damaged D1 protein. Photoinhibition is readily reversible during recovery in shaded conditions. Excessive UV stress causes photodamage which is not easily reversible. Another major target is the DNA where UV-B mainly induces thymine dimers. Cyanobacteria, phytoplankton and macroalgae produce scytonemin, mycosporine-like amino acids and other UV-absorbing substances to protect themselves from short wavelength solar radiation.

  4. In situ study of SV40 virus DNA in lytic infection by mild loosening of nucleoproteins.

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    Puvion-Dutilleul, F; Pedron, J; Lange, M

    1980-11-01

    We have studied SV40 (simian virus40) nucleoprotein in permissively infected monkey kidney cell cultures (CV1) by a procedure which does not require the isolation of the SV40 chromosomes. Treatment of the cells by a low ionic strenght medium containing Photo flo produces a mild loosening of nucleoproteins, and permits the in situ study in ultrathin sections of virus components and their relationships with host cell chromatin. RNP and DNP could be distinguished by uranyl-EDTA-lead staining (for RNP) and by DNase digestion. SV40 DNA was observed as circular molecules, either free or connected with either RNP fibrils or virus capsids. These three aspects were interpreted, respectively, as viral minichromosomes, transcription of virus genome and partially encapsidated virus DNA. During encapsidation a few virus particles appear to be bound to host chromatin. Many, if not all, seemingly mature viruses, singly or in small linear clusters, are also aligned on host chromatin. Some of these observations were corroborated by the Miller spreading technique. They are consistent with a role for the host cell chromatin in the production of nuclear viruses.

  5. Vectors bicistronically linking a gene of interest to the SV40 large T antigen in combination with the SV40 origin of replication enhance transient protein expression and luciferase reporter activity

    OpenAIRE

    Mahon, Matthew J.

    2011-01-01

    The Simian Virus large T antigen (SVLT) induces replication of plasmids bearing the SV40 origin of replication (SV40 ori) within mammalian cells. The internal ribosomal entry site (IRES) is an element that allows for the co-translation of proteins from one polycistronic mRNA. Through the combination of these elements, IRES-dependent co-expression of a protein of interest and the SVLT, either constitutive or regulated, on plasmids bearing the SV40 ori generates a positive feedback loop, result...

  6. Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, R.M.B. [Universidade Tecnica, Lisbon (Portugal). Inst. Superior de Agronomia]|[Universidade Nova de Lisboa, Oeiras (Portugal). Instituto de Tecnologia Quimica e Biologica; Franco, E.; Teixeira, A.R.N. [Universidade Tecnica, Lisbon (Portugal). Inst. Superior de Agronomia

    1996-08-15

    The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a 65 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of {sup 35}S-labelled ribulose biphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose biphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose biphosphate carboxylase. For short periods of time (<1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose biphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photosynthetic tissues. (Author).

  7. Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation.

    Science.gov (United States)

    Ferreira, R M; Franco, E; Teixeira, A R

    1996-08-15

    The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a +5 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of 35S-labelled ribulose bisphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose bisphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose bisphosphate carboxylase. For short periods of time (extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photo-synthetic tissues.

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

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    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

  9. Physics of Electrodeless UV Lamps and Applications of UV Radiation

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    Cekic, Miodrag; Ruckman, Mark

    2004-12-01

    Electrodeless discharge microwave powered ultraviolet limps are a special class of high power incoherent UV sources, conceptualized forty years ago for industrial processing applications. Because of the nonimaging character of the applications, the need for measuring averaged properties of the lamps' exceeds the motivation to obtain detailed space-resolved discharge parameters. This writing discusses measurements of the average plasma temperature of a 5.8kW high pressure mercury bulb and a XeCl* excimer bulb driven by the microwaves of the same power. First method is based on the black body radiance fit to the self-absorbed 185nm and 254nm mercury lines. The second method is essentially Boltzmann plot method applied to the roto-vibrational levels of B1/2 - X1/2 XeCl* molecular transition with a maximum at 308nm. We also present a procedure for evaluation of effectiveness of different bulb spectra to the given UV curing chemistry system independent from the Beer-Lambert law. Conversely, the procedure can be used for the optimization of the chemistry to the chosen UV lamp radiance spectrum.

  10. Effective UV radiation dose in polyethylene exposed to weather

    Science.gov (United States)

    González-Mota, R.; Soto-Bernal, J. J.; Rosales-Candelas, I.; Calero Marín, S. P.; Vega-Durán, J. T.; Moreno-Virgen, R.

    2009-09-01

    In this work we quantified the effective UV radiation dose in orange and colorless polyethylene samples exposed to weather in the city of Aguascalientes, Ags. Mexico. The spectral distribution of solar radiation was calculated using SMART 2.9.5.; the samples absorption properties were measured using UV-Vis spectroscopy and the quantum yield was calculated using samples reflectance properties. The determining factor in the effective UV dose is the spectral distribution of solar radiation, although the chemical structure of materials is also important.

  11. Ultraviolet Radiation Effects On UV-Transmitting Fluor Crown Glasses

    Science.gov (United States)

    Liepmann, Monika J.; Marker, Alexander J.; Sowada, Ulrich

    1989-01-01

    Fluor crown glasses, having improved transparency in the UV-spectral region, can be produced by using a proprietary melting technique. The short wavelength cut on of this family of UV-transmitting glasses is similar to that of vitreous silica. In the present investigation the effect of broadband UV-radiation has been studied as a function of time and optical absorption primarily for the glass type UVFK-54. Further tests were performed using discrete line radiation of 248 nm from a pulsed excimer laser. The intensity of the darkening effect is correlated to the intensity and dose of radiation. In addition, recovery experiments using elevated temperatures and different times are discussed.

  12. UV Irradiance Enhancements by Scattering of Solar Radiation from Clouds

    Directory of Open Access Journals (Sweden)

    Uwe Feister

    2015-08-01

    Full Text Available Scattering of solar radiation by clouds can reduce or enhance solar global irradiance compared to cloudless-sky irradiance at the Earth’s surface. Cloud effects to global irradiance can be described by Cloud Modification Factors (CMF. Depending on strength and duration, irradiance enhancements affect the energy balance of the surface and gain of solar power for electric energy generation. In the ultraviolet region, they increase the risk for damage to living organisms. Wavelength-dependent CMFs have been shown to reach 1.5 even in the UV-B region at low altitudes. Ground-based solar radiation measurements in the high Andes region at altitudes up to 5917 m a.s.l showed cloud-induced irradiance enhancements. While UV-A enhancements were explained by cloud scattering, both radiation scattering from clouds and Negative Ozone Anomalies (NOA have been discussed to have caused short-time enhancement of UV-B irradiance. Based on scenarios using published CMF and additional spectroradiometric measurements at a low-altitude site, the contribution of cloud scattering to the UV-B irradiance enhancement in the Andes region has been estimated. The range of UV index estimates converted from measured UV-B and UV-A irradiance and modeled cloudless-sky ratios UV-B/erythemal UV is compatible with an earlier estimate of an extreme UV index value of 43 derived for the high Andes.

  13. Uv- and Gamma-Radiation Sensitive Mutants of Arabidopsis Thaliana

    OpenAIRE

    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 in...

  14. Effects of Ultraviolet (UV) Radiations at Different Wave Lengths on ...

    African Journals Online (AJOL)

    Prof. Ogunji

    biotechsocietynigeria.org. Short Communication. Effects of Ultraviolet (UV) Radiations at Different Wave Lengths on the Microbial Load ... stained blue while the living cells reduced the stain and remained colourless. The viability of the yeast ...

  15. Ambient solar UV radiation and seasonal trends in potential sunburn ...

    African Journals Online (AJOL)

    potentially high, sunburn-causing solar UV radiation levels while at school. Method. ... Some sun exposure is important for vitamin D production1 and protection ..... However, many schools schedule lunch breaks in the 2-hour period either.

  16. Vectors bicistronically linking a gene of interest to the SV40 large T antigen in combination with the SV40 origin of replication enhance transient protein expression and luciferase reporter activity.

    Science.gov (United States)

    Mahon, Matthew J

    2011-08-01

    The simian virus 40 large T antigen (SVLT) induces replication of plasmids bearing the SV40 origin of replication (SV40 ori) within mammalian cells. The internal ribosomal entry site (IRES) is an element that allows for the cotranslation of proteins from one polycistronic mRNA. Through the combination of these elements, IRES-dependent coexpression of a protein of interest and the SVLT, either constitutive or regulated, on plasmids bearing the SV40 ori generates a positive feedback loop, resulting in enhanced expression. A vector linking red fluorescent protein (RFP) to the IRES-SVLT element enhances fluorescence ~10-fold over that demonstrated from a vector lacking this element. In transfection-resistant CV-1 cells, the RFP-IRES-SVLT vector substantially increases the number of cells expressing detectable levels of RFP. Furthermore, inclusion of the IRES-SVLT/SV40 ori elements in standard luciferase-based reporter gene constructs and associated effectors results in marked increases in luminescent output and sensitivity, using the β-catenin/TCF pathway and the mammalian two-hybrid assay as models. Ultimately, vector systems combining these well-established elements (IRES-SVLT/SV40 ori) will increase the utility of transient transfection for the production of recombinant proteins, the use of transfection-resistant cell lines, and the effectiveness of luciferase-based high-throughput screening assays.

  17. Effects of Ultraviolet (UV) Radiations at Different Wave Lengths on ...

    African Journals Online (AJOL)

    Prof. Ogunji

    Abstract. The effects of UV-radiation on the bacterial load and yeast viability of palm wine were investigated. In the studies 500ml of fresh palm wine sample each with initial yeast viability of 100% and bacterial load of 8.0 x 1015 Cfu/ml was exposed to UV-radiation at various wave lengths and time of 0 to 7hrs.

  18. Transformation of SV40-immortalized human uroepithelial cells by 3-methylcholanthrene increases IFN- and Large T Antigen-induced transcripts

    Directory of Open Access Journals (Sweden)

    Easton Marilyn J

    2010-02-01

    Full Text Available Abstract Background Simian Virus 40 (SV40 immortalization followed by treatment of cells with 3-methylcholanthrene (3-MC has been used to elicit tumors in athymic mice. 3-MC carcinogenesis has been thoroughly studied, however gene-level interactions between 3-MC and SV40 that could have produced the observed tumors have not been explored. The commercially-available human uroepithelial cell lines were either SV40-immortalized (HUC or SV40-immortalized and then 3-MC-transformed (HUC-TC. Results To characterize the SV40 - 3MC interaction, we compared human gene expression in these cell lines using a human cancer array and confirmed selected changes by RT-PCR. Many viral Large T Antigen (Tag expression-related changes occurred in HUC-TC, and it is concluded that SV40 and 3-MC may act synergistically to transform cells. Changes noted in IFP 9-27, 2'-5' OAS, IF 56, MxA and MxAB were typical of those that occur in response to viral exposure and are part of the innate immune response. Because interferon is crucial to innate immune host defenses and many gene changes were interferon-related, we explored cellular growth responses to exogenous IFN-γ and found that treatment impeded growth in tumor, but not immortalized HUC on days 4 - 7. Cellular metabolism however, was inhibited in both cell types. We conclude that IFN-γ metabolic responses were functional in both cell lines, but IFN-γ anti-proliferative responses functioned only in tumor cells. Conclusions Synergism of SV40 with 3-MC or other environmental carcinogens may be of concern as SV40 is now endemic in 2-5.9% of the U.S. population. In addition, SV40-immortalization is a generally-accepted method used in many research materials, but the possibility of off-target effects in studies carried out using these cells has not been considered. We hope that our work will stimulate further study of this important phenomenon.

  19. Radiative symmetry breaking from interacting UV fixed points

    Science.gov (United States)

    Abel, Steven; Sannino, Francesco

    2017-09-01

    It is shown that the addition of positive mass-squared terms to asymptotically safe gauge-Yukawa theories with perturbative UV fixed points leads to calculable radiative symmetry breaking in the IR. This phenomenon, and the multiplicative running of the operators that lies behind it, is akin to the radiative symmetry breaking that occurs in the supersymmetric standard model.

  20. UV- Radiation Absorption by Ozone in a Model Atmosphere using ...

    African Journals Online (AJOL)

    UV- radiation absorption is studied through variation of ozone transmittance with altitude in the atmosphere for radiation in the 9.6μm absorption band using Goody's model atmosphere with cubic spline interpolation technique to improve the quality of the curve. The data comprising of pressure and temperature at different ...

  1. Protective effect of UV-A radiation during acclimation of the photosynthetic apparatus to UV-B treatment.

    Science.gov (United States)

    Štroch, Michal; Materová, Zuzana; Vrábl, Daniel; Karlický, Václav; Šigut, Ladislav; Nezval, Jakub; Špunda, Vladimír

    2015-11-01

    We examined the acclimation response of the photosynthetic apparatus of barley (Hordeum vulgare L.) to a combination of UV-A and UV-B radiation (UVAB) and to UV-B radiation alone. Our aim was to evaluate whether UV-A radiation prevents UV-B-induced damage to the photosynthetic apparatus and whether UV-A pre-acclimation is required to mitigate the negative influence of UV-B radiation. Barley plants were grown from seeds under low photosynthetically active radiation (50 μmol m(-2) s(-1)) either in the absence or presence of UV-A radiation (UVA- and UVA+ plants, respectively). After 8 days of development, plants were exposed simultaneously to UV-A and UV-B radiation for the next 6 days. Additionally, UVA- plants were exposed to UV-B radiation alone. The UVA+ plants had a higher CO2 assimilation rate near the light-saturation region (A(N)) and a higher content of both total chlorophylls (Chls) and total carotenoids than the UVA- plants. Chls content, A(N), the potential quantum yield of photosystem II (PSII) photochemistry (F(V)/F(M)), the capacity of light-induced thermal energy dissipation and the efficiency of excitation energy transfer within PSII remained the same or even increased in both UVA+ and UVA- plants after UVAB treatment. On the contrary, exposure of UVA- plants to UV-B radiation itself led to a reduction in all these characteristics. We revealed that the presence of UV-A radiation during UVAB treatment not only mitigated but completely eliminated the negative effect of UV-B radiation on the functioning of the photosynthetic apparatus and that UV-A pre-acclimation was not crucial for development of this UV-A-induced resistance against UV-B irradiation. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  2. Chimeric SV40 virus-like particles induce specific cytotoxicity and protective immunity against influenza A virus without the need of adjuvants

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Masaaki [Department of Allergy and Immunology, Faculty of Medicine, Saitama Medical University, Moroyama-cho, Iruma-gun, Saitama 350-0495 (Japan); Morikawa, Katsuma [Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501 (Japan); Suda, Tatsuya [Department of Microbiology, Faculty of Medicine, Saitama Medical University, Moroyama-cho, Iruma-gun, Saitama 350-0495 (Japan); Laboratory for Immunopharmacology of Microbial Products, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392 (Japan); Ohno, Naohito [Laboratory for Immunopharmacology of Microbial Products, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392 (Japan); Matsushita, Sho [Department of Allergy and Immunology, Faculty of Medicine, Saitama Medical University, Moroyama-cho, Iruma-gun, Saitama 350-0495 (Japan); Allergy Center, Saitama Medical University, Moroyama-cho, Iruma-gun, Saitama 350-0495 (Japan); Akatsuka, Toshitaka [Department of Microbiology, Faculty of Medicine, Saitama Medical University, Moroyama-cho, Iruma-gun, Saitama 350-0495 (Japan); Handa, Hiroshi, E-mail: handa.h.aa@m.titech.ac.jp [Solutions Research Laboratory, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8503 (Japan); Matsui, Masanori, E-mail: mmatsui@saitama-med.ac.jp [Department of Microbiology, Faculty of Medicine, Saitama Medical University, Moroyama-cho, Iruma-gun, Saitama 350-0495 (Japan)

    2014-01-05

    Virus-like particles (VLPs) are a promising vaccine platform due to the safety and efficiency. However, it is still unclear whether polyomavirus-based VLPs are useful for this purpose. Here, we attempted to evaluate the potential of polyomavirus VLPs for the antiviral vaccine using simian virus 40 (SV40). We constructed chimeric SV40-VLPs carrying an HLA-A{sup ⁎}02:01-restricted, cytotoxic T lymphocyte (CTL) epitope derived from influenza A virus. HLA-A{sup ⁎}02:01-transgenic mice were then immunized with the chimeric SV40-VLPs. The chimeric SV40-VLPs effectively induced influenza-specific CTLs and heterosubtypic protection against influenza A viruses without the need of adjuvants. Because DNase I treatment of the chimeric SV40-VLPs did not disrupt CTL induction, the intrinsic adjuvant property may not result from DNA contaminants in the VLP preparation. In addition, immunization with the chimeric SV40-VLPs generated long-lasting memory CTLs. We here propose that the chimeric SV40-VLPs harboring an epitope may be a promising CTL-based vaccine platform with self-adjuvant properties. - Highlights: • We constructed chimeric SV40-VLPs carrying an influenza virus-derived CTL epitope. • Chimeric SV40-VLPs induce influenza-specific CTLs in mice without adjuvants. • Chimeric SV40-VLPs induce heterosubtypic protection against influenza A viruses. • Chimeric SV40-VLPs induce long-lasting memory CTLs. • Chimeric SV40-VLPs is a promising vaccine platform with self-adjuvant properties.

  3. Carotenoids and protection against solar UV radiation.

    Science.gov (United States)

    Stahl, Wilhelm; Sies, Helmut

    2002-01-01

    Upon exposure to UV light photooxidative reactions are initiated which are damaging to biomolecules and affect the integrity of cells and tissues. Photooxidative damage plays a role in pathological processes and is involved in the development of disorders affecting the skin. When skin is exposed to UV light, erythema is observed as an initial reaction. Carotenoids like beta-carotene or lycopene are efficient antioxidants scavenging singlet molecular oxygen and peroxyl radicals generated in during photooxidation. When beta-carotene was applied as such or in combination with alpha-tocopherol for 12 weeks, erythema formation induced with a solar light simulator was diminished from week 8 on. Similar effects were also achieved with a diet rich in lycopene. Ingestion of tomato paste corresponding to a dose of 16 mg lycopene/ day over 10 weeks led to increases in serum levels of lycopene and total carotenoids in skin. At week 10, erythema formation was significantly lower in the group that ingested the tomato paste as compared to the control group. No significant difference was found at week 4 of treatment. Thus, protection against UV light-induced erythema can be achieved by ingestion of a commonly consumed dietary source of lycopene. Such protective effects of carotenoids were also demonstrated in cell culture. The in-vitro data indicate that there is an optimal level of protection for each carotenoid. Copyright 2002 S. Karger AG, Basel

  4. Generation of a Vero-Based Packaging Cell Line to Produce SV40 Gene Delivery Vectors for Use in Clinical Gene Therapy Studies

    Directory of Open Access Journals (Sweden)

    Miguel G. Toscano

    2017-09-01

    Full Text Available Replication-defective (RD recombinant simian virus 40 (SV40-based gene delivery vectors hold a great potential for clinical applications because of their presumed non-immunogenicity and capacity to induce immune tolerance to the transgene products in humans. However, the clinical use of SV40 vectors has been hampered by the lack of a packaging cell line that produces replication-competent (RC free SV40 particles in the vector production process. To solve this problem, we have adapted the current SV40 vector genome used for the production of vector particles and generated a novel Vero-based packaging cell line named SuperVero that exclusively expresses the SV40 large T antigen. SuperVero cells produce similar numbers of SV40 vector particles compared to the currently used packaging cell lines, albeit in the absence of contaminating RC SV40 particles. Our unique SV40 vector platform named SVac paves the way to clinically test a whole new generation of SV40-based therapeutics for a broad range of important diseases.

  5. BIOLOGICALLY ACTIVE UV-RADIATION AND UV-RESOURCES IN MOSCOW (1999-2013

    Directory of Open Access Journals (Sweden)

    Ekaterina Yu. Zhdanova

    2014-01-01

    Full Text Available The paper contains the analysis of long-term measurements of erythemally weighted UV-radiation (Qer at the Meteorological Observatory of Moscow State University over the 1999-2013 period. Main features of seasonal variability of Qer as well as the Qer dependence on different geophysical parameters are studied. We showed that the average annual Qer attenuation due to cloudiness, total ozone content, and aerosols, is about 29, 30%, and 7%, respectively. The maximal loss of Qer due to cloudiness is observed in November (48%, while ozone-dependent attenuation is maximal in February-March (44%. We used the original technique to assess the UV-radiation impact on human health in Moscow. Specifically, we have identified the UV potential for the erythema formation and synthesis of vitamin D in humans with different skin types. The UV-deficiency conditions are observed for all considered skin types (1-4 during all days from November to February. The probability of the UV-optimum conditions for different skin types was assessed. It was shown, for example, that for skin type 2, the UV-optimum conditions are dominant from March to April and from September to October (maximum in September - 60%. We have also identified the periods with UV-excess conditions. For skin type 2, these conditions may exist from April to August.

  6. Susceptibility of Campylobacter jejuni and Yersinia enterocolitica to UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Butler, R.C.; Lund, V.; Carlson, D.A.

    1987-02-01

    Two enteric pathogens, Campylobacter jejuni and Yersinia enterocolitica serogroup O:3, together with Escherichia coli, were investigated for susceptibility to UV radiation at 254 nm. The UV dose required for a 3-log reduction (99.9% inactivation) of C. jejuni, Y. enterocolitica, and E. coli was 1.8, 2.7, and 5.0 mWs/cm2, respectively. Using E. coli as the basis for comparison, it appears that C. jejuni and Y. enterocolitica serogroup O:3 are more sensitive to UV than many of the pathogens associated with waterborne disease outbreaks and can be easily inactivated in most commercially available UV reactors. No association was found between the sensitivity of Y. enterocolitica to UV and the presence of a 40- to 50-megadalton virulence plasmid.

  7. Effect of UV Radiation by Projectors on 3D Printing

    Directory of Open Access Journals (Sweden)

    Kovalenko Iaroslav

    2017-01-01

    Full Text Available Polymers that solidify under light radiation are commonly used in digital light processing (DLP 3D printing. A wide range of photopolymers use photoinitiators that react to radiation in range of ultraviolet (UV wavelength. In the present study we provided measurement of radiant fluence in the UV wavelength range from 280 nm to 400 nm for two data projectors and compared effect of radiation on quality of 3D printing. One projector is commonly used DLP projector with high energy lamp. Second one is an industrial projector, in which RGB light emitting diodes (LEDs are replaced by UV LEDs with wattage at the level of 3.6 % of the first one. Achieved data confirmed uneven distribution of radiant energy on illuminated area. These results validate, that undesired heating light causes internal stress inside built models that causes defects in final products.

  8. Ozone depletion and climate change: impacts on UV radiation.

    Science.gov (United States)

    Bais, A F; McKenzie, R L; Bernhard, G; Aucamp, P J; Ilyas, M; Madronich, S; Tourpali, K

    2015-01-01

    We assess the importance of factors that determine the intensity of UV radiation at the Earth's surface. Among these, atmospheric ozone, which absorbs UV radiation, is of considerable importance, but other constituents of the atmosphere, as well as certain consequences of climate change, can also be major influences. Further, we assess the variations of UV radiation observed in the past and present, and provide projections for the future. Of particular interest are methods to measure or estimate UV radiation at the Earth's surface. These are needed for scientific understanding and, when they are sufficiently sensitive, they can serve as monitors of the effectiveness of the Montreal Protocol and its amendments. Also assessed are several aspects of UV radiation related to biological effects and health. The implications for ozone and UV radiation from two types of geoengineering methods that have been proposed to combat climate change are also discussed. In addition to ozone effects, the UV changes in the last two decades, derived from measurements, have been influenced by changes in aerosols, clouds, surface reflectivity, and, possibly, by solar activity. The positive trends of UV radiation observed after the mid-1990s over northern mid-latitudes are mainly due to decreases in clouds and aerosols. Despite some indications from measurements at a few stations, no statistically significant decreases in UV-B radiation attributable to the beginning of the ozone recovery have yet been detected. Projections for erythemal irradiance (UVery) suggest the following changes by the end of the 21(st) century (2090-2100) relative to the present time (2010-2020): (1) Ozone recovery (due to decreasing ozone-depleting substances and increasing greenhouse gases) would cause decreases in UVery, which will be highest (up to 40%) over Antarctica. Decreases would be small (less than 10%) outside the southern Polar Regions. A possible decline of solar activity during the 21(st) century

  9. SV40 utilizes ATM kinase activity to prevent non-homologous end joining of broken viral DNA replication products.

    Science.gov (United States)

    Sowd, Gregory A; Mody, Dviti; Eggold, Joshua; Cortez, David; Friedman, Katherine L; Fanning, Ellen

    2014-12-01

    Simian virus 40 (SV40) and cellular DNA replication rely on host ATM and ATR DNA damage signaling kinases to facilitate DNA repair and elicit cell cycle arrest following DNA damage. During SV40 DNA replication, ATM kinase activity prevents concatemerization of the viral genome whereas ATR activity prevents accumulation of aberrant genomes resulting from breakage of a moving replication fork as it converges with a stalled fork. However, the repair pathways that ATM and ATR orchestrate to prevent these aberrant SV40 DNA replication products are unclear. Using two-dimensional gel electrophoresis and Southern blotting, we show that ATR kinase activity, but not DNA-PK(cs) kinase activity, facilitates some aspects of double strand break (DSB) repair when ATM is inhibited during SV40 infection. To clarify which repair factors associate with viral DNA replication centers, we examined the localization of DSB repair proteins in response to SV40 infection. Under normal conditions, viral replication centers exclusively associate with homology-directed repair (HDR) and do not colocalize with non-homologous end joining (NHEJ) factors. Following ATM inhibition, but not ATR inhibition, activated DNA-PK(cs) and KU70/80 accumulate at the viral replication centers while CtIP and BLM, proteins that initiate 5' to 3' end resection during HDR, become undetectable. Similar to what has been observed during cellular DSB repair in S phase, these data suggest that ATM kinase influences DSB repair pathway choice by preventing the recruitment of NHEJ factors to replicating viral DNA. These data may explain how ATM prevents concatemerization of the viral genome and promotes viral propagation. We suggest that inhibitors of DNA damage signaling and DNA repair could be used during infection to disrupt productive viral DNA replication.

  10. SV40 Infection of Mesenchymal Stromal Cells From Wharton's Jelly Drives the Production of Inflammatory and Tumoral Mediators.

    Science.gov (United States)

    Cason, Carolina; Campisciano, Giuseppina; Zanotta, Nunzia; Valencic, Erica; Delbue, Serena; Bella, Ramona; Comar, Manola

    2017-11-01

    The Mesenchymal Stromal Cells from umbilical cord Wharton's jelly (WJSCs) are a source of cells with high potentiality for the treatment of human immunological disorders. Footprints of the oncogenic viruses Simian Virus 40 (SV40) and JC Virus (JCPyV) have been recently detected in human WJSCs specimens. The aim of this study is to evaluate if WJSCs can be efficiently infected by these Polyomaviruses and if they can potentially exert tumoral activity. Cell culture experiments indicated that WJSCs could sustain both SV40 and JCPyV infections. A transient and lytic replication was observed for JCPyV, while SV40 persistently infected WJSCs over a long period of time, releasing a viral progeny at low titer without evident cytopathic effect (CPE). Considering the association between SV40 and human tumors and the reported ability of the oncogenic viruses to drive the host innate immune response to cell transformation, the expression profile of a large panel of immune mediators was evaluated in supernatants by the Bioplex platform. RANTES, IL-3, MIG, and IL-12p40, involved in chronic inflammation, cells differentiation, and transformation, were constantly measured at high concentration comparing to control. These findings represent a new aspect of SV40 biological activity in the humans, highlighting its interaction with specific host cellular pathways. In view of these results, it seems to be increasingly urgent to consider Polyomaviruses in the management of WJSCs for their safely use as promising therapeutic source. J. Cell. Physiol. 232: 3060-3066, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. SV40 Utilizes ATM Kinase Activity to Prevent Non-homologous End Joining of Broken Viral DNA Replication Products

    Science.gov (United States)

    Sowd, Gregory A.; Mody, Dviti; Eggold, Joshua; Cortez, David; Friedman, Katherine L.; Fanning, Ellen

    2014-01-01

    Simian virus 40 (SV40) and cellular DNA replication rely on host ATM and ATR DNA damage signaling kinases to facilitate DNA repair and elicit cell cycle arrest following DNA damage. During SV40 DNA replication, ATM kinase activity prevents concatemerization of the viral genome whereas ATR activity prevents accumulation of aberrant genomes resulting from breakage of a moving replication fork as it converges with a stalled fork. However, the repair pathways that ATM and ATR orchestrate to prevent these aberrant SV40 DNA replication products are unclear. Using two-dimensional gel electrophoresis and Southern blotting, we show that ATR kinase activity, but not DNA-PKcs kinase activity, facilitates some aspects of double strand break (DSB) repair when ATM is inhibited during SV40 infection. To clarify which repair factors associate with viral DNA replication centers, we examined the localization of DSB repair proteins in response to SV40 infection. Under normal conditions, viral replication centers exclusively associate with homology-directed repair (HDR) and do not colocalize with non-homologous end joining (NHEJ) factors. Following ATM inhibition, but not ATR inhibition, activated DNA-PKcs and KU70/80 accumulate at the viral replication centers while CtIP and BLM, proteins that initiate 5′ to 3′ end resection during HDR, become undetectable. Similar to what has been observed during cellular DSB repair in S phase, these data suggest that ATM kinase influences DSB repair pathway choice by preventing the recruitment of NHEJ factors to replicating viral DNA. These data may explain how ATM prevents concatemerization of the viral genome and promotes viral propagation. We suggest that inhibitors of DNA damage signaling and DNA repair could be used during infection to disrupt productive viral DNA replication. PMID:25474690

  12. SV40 utilizes ATM kinase activity to prevent non-homologous end joining of broken viral DNA replication products.

    Directory of Open Access Journals (Sweden)

    Gregory A Sowd

    2014-12-01

    Full Text Available Simian virus 40 (SV40 and cellular DNA replication rely on host ATM and ATR DNA damage signaling kinases to facilitate DNA repair and elicit cell cycle arrest following DNA damage. During SV40 DNA replication, ATM kinase activity prevents concatemerization of the viral genome whereas ATR activity prevents accumulation of aberrant genomes resulting from breakage of a moving replication fork as it converges with a stalled fork. However, the repair pathways that ATM and ATR orchestrate to prevent these aberrant SV40 DNA replication products are unclear. Using two-dimensional gel electrophoresis and Southern blotting, we show that ATR kinase activity, but not DNA-PK(cs kinase activity, facilitates some aspects of double strand break (DSB repair when ATM is inhibited during SV40 infection. To clarify which repair factors associate with viral DNA replication centers, we examined the localization of DSB repair proteins in response to SV40 infection. Under normal conditions, viral replication centers exclusively associate with homology-directed repair (HDR and do not colocalize with non-homologous end joining (NHEJ factors. Following ATM inhibition, but not ATR inhibition, activated DNA-PK(cs and KU70/80 accumulate at the viral replication centers while CtIP and BLM, proteins that initiate 5' to 3' end resection during HDR, become undetectable. Similar to what has been observed during cellular DSB repair in S phase, these data suggest that ATM kinase influences DSB repair pathway choice by preventing the recruitment of NHEJ factors to replicating viral DNA. These data may explain how ATM prevents concatemerization of the viral genome and promotes viral propagation. We suggest that inhibitors of DNA damage signaling and DNA repair could be used during infection to disrupt productive viral DNA replication.

  13. A human corneal equivalent constructed from SV40-immortalised corneal cell lines.

    Science.gov (United States)

    Zorn-Kruppa, Michaela; Tykhonova, Svitlana; Belge, Gazanfer; Bednarz, Jürgen; Diehl, Horst A; Engelke, Maria

    2005-02-01

    Within the last decade, extensive research in the field of tissue and organ engineering has focused on the development of in vitro models of the cornea. The use of organotypic, three-dimensional corneal equivalents has several advantages over simple monolayer cultures. The aim of this study was to develop a corneal equivalent model composed of the same cell types as in the natural human tissue, but by using immortalised cell lines to ensure reproducibility and to minimise product variation. We report our success in the establishment of an SV40-immortalised human corneal keratocyte cell line (designated HCK). A collagen matrix, built up with these cells, displayed the morphological characteristics of the human stromal tissue and served as a biomatrix for the immortalised human corneal epithelial and endothelial cells. Histological cross-sections of the whole-cornea equivalents resemble human corneas in tissue structure. This organotypic in vitro model may serve as a research tool for the ophthalmic science community, as well as a model system for testing for eye irritancy and drug efficacy.

  14. SV40-transformed human corneal keratocytes: optimisation of serum-free culture conditions.

    Science.gov (United States)

    Manzer, Anna Katharina; Lombardi-Borgia, Simone; Schäfer-Korting, Monika; Seeber, Judith; Zorn-Kruppa, Michaela; Engelke, Maria

    2009-01-01

    Aiming at the replacement of animal experiments in eye irritation testing, we have established a multilay ered cornea model comprising the co-culture of all three corneal cell types. It was the objective of this study to optimise serum-free culture conditions to preserve both growth and phenotype of an SV40-immortalised human corneal keratocyte cell line (HCK). Our results revealed that HCK continue to proliferate in both monolayer cultures as well as after seeding in a collagen matrix and resemble primary corneal keratocytes in morphology and functional characteristics under defined serum-free conditions. Furthermore, HCK were shown to transform into activated corneal fibroblast phenotypes in response to serum and TGF(beta)1. In summary, HCK cells mimic their in vivo (primary) precursors, both in sustaining the quiescent keratocyte phenotype (serum-starved conditions) and in responding to growth factor stimulation. Hence, this cell line may provide a useful tool to study the toxicity and wound healing response of corneal keratocytes in vitro.

  15. Abrogation of p53-mediated transactivation by SV40 large T antigen.

    Science.gov (United States)

    Segawa, K; Minowa, A; Sugasawa, K; Takano, T; Hanaoka, F

    1993-03-01

    p53 is known to bind specifically to the 44-bp human DNA sequence in an immunoprecipitation assay. We show here that the transcription of the reporter CAT gene linked with the herpesvirus thymidine kinase (tk) promoter containing the 44-base sequence is enhanced by mouse wild-type but not mutant-type p53 in F9 and p53-null Saos-2 cells. The p53-mediated transactivation was dramatically abrogated by introduction of SV40 large T antigen (SVLT) in Saos-2 cells in which p53 was clearly associated with SVLT. Furthermore, the p53-SVLT complex did not bind to the 44-base sequence at all. Thus, SVLT sequesters the transactivation function of the wild-type p53 by inhibiting the binding of p53 to the 44-base sequence. This is good evidence to show 'loss of functions' in the product of a tumor-suppressor oncogene by a dominant oncogene product at a molecular level.

  16. Reduction of patulin in apple cider by UV radiation.

    Science.gov (United States)

    Dong, Qingfang; Manns, David C; Feng, Guoping; Yue, Tianli; Churey, John J; Worobo, Randy W

    2010-01-01

    The presence of the mycotoxin patulin in processed apple juice and cider presents a continual challenge to the food industry as both consumer health and product quality issues. Although several methods for control and/or elimination of patulin have been proposed, no unifying method has been commercially successful for reducing patulin burdens while maintaining product quality. In the present study, exposure to germicidal UV radiation was evaluated as a possible commercially viable alternative for the reduction and possible elimination of the patulin mycotoxin in fresh apple cider. UV exposure of 14.2 to 99.4 mJ/cm(2) resulted in a significant and nearly linear decrease in patulin levels while producing no quantifiable changes in the chemical composition (i.e., pH, Brix, and total acids) or organoleptic properties of the cider. For the range of UV doses tested, patulin levels decreased by 9.4 to 43.4%; the greatest reduction was achieved after less than 15 s of UV exposure. The method of UV radiation (the CiderSure 3500 system) is an easily implemented, high-throughput, and cost-effective method that offers simultaneous UV pasteurization of cider and juice products and reduction and/or elimination of patulin without unwanted alterations in the final product.

  17. Ambient solar UV radiation and seasonal trends in potential sunburn ...

    African Journals Online (AJOL)

    similar studies among schoolchildren in New Zealand,11 Denmark12 and England,13 and activity was the .... The solar UV-B radiation levels at the six geographical areas followed a similar annual cycle, with maximum ... exposures by geographical location as well as potential sunburn risk by skin type. Required solar UV ...

  18. Impact of UV radiation on the physical properties of polypropylene ...

    African Journals Online (AJOL)

    Textiles, used as agrotextiles require suitable tensile strength and good permeability characteristics with no significant deterioration under the influence of weather changes and UV radiation. Properties of agrotextiles depend on the fibres made of and on the type and conditions of production. The purpose of this study was ...

  19. Ambient solar UV radiation and seasonal trends in potential sunburn ...

    African Journals Online (AJOL)

    ... including fair-skinned individuals and African albinos, and people spending extended unprotected periods outdoors are at risk of sunburn, a risk factor for skin cancer. Sunburn becomes increasingly likely during the high solar UV radiation hours around midday, and previous studies have shown that children are exposed ...

  20. Ambient solar UV radiation and seasonal trends in potential sunburn ...

    African Journals Online (AJOL)

    Background. The detrimental effects of excess personal solar ultraviolet (UV) radiation exposure include sunburn, immunosuppression and skin cancer. In South Africa, individuals with minimum natural protection from melanin, including fair-skinned individuals and African albinos, and people spending extended ...

  1. Impact of UV radiation on the physical properties of polypropylene ...

    African Journals Online (AJOL)

    Jane

    2011-08-03

    Aug 3, 2011 ... showed that the properties of row cover change when radiated with UV light. Tensile, tearing and bursting properties ... under PP nonwoven row covers can be several degrees higher that ambient ones and time ..... covers and black plastic mulch on the growth and yield of 'Clemson. Spineless' okra. J. Veg.

  2. Ageing by UV radiation of an elastomer modified bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Virginie Mouillet; Fabienne Farcas; Stanislas Besson [CETE Mediterranee Pole d' activite, Aix-en-Provence (France). Laboratoire Regional des Ponts et Chaussees d' Aix-en-Provence

    2008-09-15

    Laboratory methods to simulate the short- and long-term ageing occurring during the service life of pure and polymer modified bitumens in a pavement are standardized but none of them takes into account the influence of UV radiations. If the impact of thermal ageing on the degradation of SBS elastomers in bitumens has been extensively studied, there is not study dealing with the photo-oxidation of these copolymers in a bituminous matrix. So, the aim of our study was to investigate, by FTIR spectrometry and SEC chromatography, whether the architecture of elastomers (linear or radial) might have any influence on their ageing by UV radiation in a bituminous matrix. The results show that the elastomers oxidation kinetic, unlike the disappearance kinetic of trans-butadiene double bond, does not depend on their architecture. But, when putted into the same base bitumen, the two copolymers show exactly the same oxidation kinetic and the same decreasing kinetic of trans-butadiene double bond. So, this study has revealed that inside the bituminous matrix, on the one hand, the elastomers architecture does not influence on its degradation when submitted to UV radiation and, on the other hand, there is a 'protection' of the elastomers by the studied bitumen towards UV radiation. 46 refs., 13 figs., 2 tabs.

  3. UV-C radiation based methods for aqueous metoprolol elimination

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, F.J., E-mail: fjrivas@unex.es [Departamento de Ingenieria Quimica y Quimica Fisica, Universidad de Extremadura, Facultad de Ciencias, Edificio Jose Luis Sotelo, Avenida de Elvas S/N, 06071 Badajoz (Spain); Gimeno, O.; Borralho, T.; Carbajo, M. [Departamento de Ingenieria Quimica y Quimica Fisica, Universidad de Extremadura, Facultad de Ciencias, Edificio Jose Luis Sotelo, Avenida de Elvas S/N, 06071 Badajoz (Spain)

    2010-07-15

    The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H{sub 2}O{sub 2}, UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO{sub 2}, UV-C/H{sub 2}O{sub 2}/TiO{sub 2} and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5 x 10{sup -3} mol Einstein{sup -1} at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate. Mineralization degree was negligible when no promoter was added, while low values were achieved in the presence of either inorganic peroxides or titanium dioxide. The combination of radiation, hydrogen peroxide and TiO{sub 2} increased the mineralization level up to values in the proximity of 45-50% under the best conditions investigated. The photo-Fenton process was the best system in terms of total oxidation (mineralization degree 70%) when optimum conditions were applied.

  4. Validation of an Austrian forecasting model for biologically effective UV radiation (UV index); Validierung des oesterreichischen Vorhersagemodells fuer die biologisch-effektive UV Strahlung (UV Index)

    Energy Technology Data Exchange (ETDEWEB)

    Schauberger, G.; Schmalwieser, A. [Veterinaermedizinische Univ., Vienna (Austria). Inst. fuer Medizinische Physik

    1999-07-01

    Since October 1995 there has been an Austrian forecasting service for the next day's UV index for the three model domains Austria, Europe and world. This forecasting model uses spectral irradiation intensity data measured for 16 specific wavelengths, taking into account solar altitude, height above sea level and atmospheric ozone concentration. Weighting spectral irradiation intensity according to the spectral erythematous effect curve yields a measure of biologically effective UV radiation, and subsequent normalisation with respect to 25 mW{sub biol}/m-2 relates the result to the dimension figure for the UV index. The model has been validated by means of data obtained by continuous measurement with Robertson-Berger measuring devices (site of the Vienna Veterinary Hospital: 48 15 15.47'N; 16 25.98E; elevation 153 amsl). The spectral sensitivity of these instruments is approximately the same as that of the human skin to reddening. Combining the UV index with the expected UV dose for the day permits issuing recommendations for the most suitable sun protection factor in sunblock creams as a function of users' photobiological skin type. Users of the UV index are expected to have enough personal initiative to select the UV index that most closely corresponds to their local population situation. According to the principles of UV radiation protection the performance of the model is considered poor if the measured UV index is greater than the forecast index. This happens in approx. 12% of all cases. The error frequency of positive errors (forecast values greater than measured values) reflects the degree to which extinction of UV radiation through the population occurs, as the present model does not take this factor into account. [German] Seit Oktober 1995 wird in Oesterreich taeglich eine Prognose des UV-Index fuer die drei Modelldomaenen: Oesterreich, Europa und weltweit, geltend fuer den darauf folgenden Tag, erstellt. Das oesterreichische Prognosemodell

  5. UV Radiation in an Urban Canyon in Southeast Queensland

    Science.gov (United States)

    McKinley, A. R.; Moore, M. R.; Kimlin, M. G.

    2006-12-01

    Ultraviolet radiation (UV) has the possibility to both harm and to benefit human beings when unprotected exposure occurs. After receiving small amounts of UV our bodies begin to synthesise vitamin D, which is essential for maintaining healthy bones, however excessive UV exposure can result in a variety of damaging outcomes ranging from sunburn to skin cancer and cataracts. For this reason it is very important to understand the different environments in which people encounter UV so as to better prepare the public to make smart and healthy sun exposure decisions. Each day more and more people are moving into large cities around the world and spending their time inside the urban canyon, however UV measurements are generally taken at scientific stations in open areas or on top of tall buildings, meaning that at times the environmental characteristics measured may not accurately represent those found at street-level in these highly urbanized areas. Urban canyons are home to both very tall buildings and tropospheric air pollution, each of which reduces the amount of UV reaching street-level. This study measured the varying difference between UV measurements taken at street-level and at a standard UV monitoring site on top of a building outside of the urban canyon. Investigation was conducted in the central business district (CBD) of Brisbane, Australia, which models the CBDs of large cities around the world in that it boasts a great number of tall buildings, including many skyscrapers. Data was collected under clear sky conditions at five different street-level sites in the CBD (on either side of two streets running perpendicular to one another (four sites) and in a public square) and then compared to that obtained on the same day at the Queensland University of Technology's Australian Sun and Health Research Laboratory (ASHRL), which is located 2.5 kilometres outside Brisbane's CBD. Minimum erythemal dose (MED) data was collected at each location and it was found that

  6. Effects of solar UV-B radiation on aquatic ecosystems

    Science.gov (United States)

    Häder, D.-P.

    Solar UV degrades dissolved organic carbon photolytically so that they can readily be taken up by bacterioplankton. On the other hand solar UV radiation inhibits bacterioplankton activity. Bacterioplankton productivity is far greater than previously thought and is comparable to phytoplankton primary productivity. According to the "microbial loop hypothesis," bacterioplankton is seen in the center of a food web, having a similar function to phytoplankton and protists. The penetration of UV and PAR into the water column can be measured. Marine waters show large temporal and regional differences in their concentrations of dissolved and particulate absorbing substances. A network of dosimeters (ELDONET) has been installed in Europe ranging from Abisko in Northern Sweden to Gran Canaria. Cyanobacteria are capable of fixing atmospheric nitrogen which is then made available to higher plants. The agricultural potential of cyanobacteria has been recognized as a biological fertilizer for wet soils such as in rice paddies. UV-B is known to impair processes such as growth, survival, pigmentation, motility, as well as the enzymes of nitrogen metabolism and CO 2 fixation. The marine phytoplankton represents the single most important ecosystem on our planet and produces about the same biomass as all terrestrial ecosystems taken together. It is the base of the aquatic food chain and any changes in the size and composition of phytoplankton communities will directly affect food production for humans from marine sources. Another important role of marine phytoplankton is to serve as a sink for atmospheric carbon dioxide. Recent investigations have shown a large sensitivity of most phytoplankton organisms toward solar short-wavelength ultraviolet radiation (UV-B); even at ambient levels of UV-B radiation many organisms seem to be under UV stress. Because of their requirement for solar energy, the phytoplankton dwell in the top layers of the water column. In this near-surface position

  7. Carcinogenic risks associated with radiation pollution. [UV radiation, sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Latarjet, R.

    1976-01-01

    The cancerogenic pollution by non-ionizing radiations is limited to the case of solar ultraviolet, whose activity at ground level may be increased as a consequence of the stratospheric depletion of ozone, produced by certain chemical pollutants: nitrogen oxides from supersonic aircrafts, freon. As regards ionizing radiations, the discussion is focused on the fundamental problem of the threshold, and on the means by which one may obtain some quantitative data related to carcinogenesis by small radiation doses in man. A new concept, that of a practical threshold, is proposed. A theory which links radiocancerogenesis, as well as chemical cancerogenesis, to errors produced in the repair of lesions in the DNA is discussed. The rads-equivalent project for chemical mutagens and carcinogens is described.

  8. Worldwide forecast of the biologically effective UV radiation: UV index and daily dose

    Science.gov (United States)

    Schmalwieser, Alois W.; Schauberger, Guenther; Janouch, Michal; Nunez, Manuel; Koskela, Tapani; Berger, Daniel; Karamanian, Gabriel; Prosek, Pavel; Laska, Kamil

    2002-01-01

    Since October 1995 a global daily forecast of the UV index and the daily dose, as the irradiance of the biologically effective ultraviolet radiation, for clear sky is calculated. The Austrian model as well as the input parameters are described. By connecting the daily dose with the sensitivity of the photobiological skin types, a recommendation is given to select an appropriate sun protection factor of a sunscreen to avoid overexposure of the skin. The validation of the Austrian forecast model is done by long-term measurements of the biologically effective ultraviolet radiation. Measurements were taken from 6 different sites at 4 continents (Antarctica, Australia, America and Europe) covering the latitudinal range from 67 degree(s)N to 60 degree(s)S. By using the underestimation as criteria in the sense of radiation protection, the Austrian model shows less than 12% underestimation over the whole period for the UV index and less than 10% for the daily dose. The evaluation shows further that the forecast of the daily dose is much more influenced by the attenuation due to clouds than the UV index.

  9. Weathering of coil-coatings: UV radiation and thermal effects

    Directory of Open Access Journals (Sweden)

    Castela, A. S.

    2003-12-01

    Full Text Available The effect of heat and of QUV ageing on coil coatings was tested by electrochemical impedance, and the results compared with surface analysis of the polymers by FTIR and XPS. It was shown that UV radiation is more relevant than heat to chemical degradation. A different correlation between water permeation and chemical degradation was observed depending on the coating thickness: for the thinner coatings, the higher UV degradation has corresponded to increased water absorption, whereas in the thicker coating, the bulk effect of heat was more relevant to water permeation.

    El efecto del calor y del envejecimiento, QUV, sobre recubrimiemtos de bobinas se probó mediante la impedancia electroquímica, y los resultados se compararon con análisis superficiales de los polímeros usando FTIR y XPS. Se encontró que la radiación UV es más importante que el calor en la degradación química. Una correlación diferente, entre agua infiltrada y degradación química, se observó, dependiendo del espesor del recubrimiento: para los recubrimientos más delgados, mayor degradación UV correspondió a un incremento de absorción de agua; en cambio, para los recubrimientos más gruesos, el efecto del calor fue más importante para la infiltración del agua.

  10. Intercomparison of spectral-UV-radiation measurement systems.

    Science.gov (United States)

    Seckmeyer, G; Thiel, S; Blumthaler, M; Fabian, P; Gerber, S; Gugg-Helminger, A; Häder, D P; Huber, M; Kettner, C; Köhler, U; Köpke, P; Maier, H; Schäfer, J; Suppan, P; Tamm, E; Thomalla, E

    1994-11-20

    The results of what is to our knowledge the first intercomparison of seven independent spectroradiometers measuring solar UV irradiances are presented. The intercomparison was carried out in the GSF-Forschungszentrum für Umwelt und Gesundheit, Neuherberg (near Munich, Germany), on 13 July 1990. The spectroradiometric measurements were supplemented by other meteorological, optical, and chemical measurements at the same time. As this day was cloudless, the data can be compared with the measurements taken by Bener in Switzerland in the 1960's and with the results of radiative transfer models. The measured irradiances at noon differed by factors of up to 100. These large differences demonstrate the great difficulties with this type of measurement. Some instrument systems, however, ranged within tolerances of ±10%, thus allowing us to make recommendations for the spectroradiometry of solar UV irradiances.

  11. Comparative Transcriptome Profiling of an SV40-Transformed Human Fibroblast (MRC5CVI) and Its Untransformed Counterpart (MRC-5) in Response to UVB Irradiation

    OpenAIRE

    Cheng-Wei Chang; Chaang-Ray Chen; Chao-Ying Huang; Wun-Yi Shu; Chi-Shiun Chiang; Ji-Hong Hong; Hsu, Ian C.

    2013-01-01

    Simian virus 40 (SV40) transforms cells through the suppression of tumor-suppressive responses by large T and small t antigens; studies on the effects of these two oncoproteins have greatly improved our knowledge of tumorigenesis. Large T antigen promotes cellular transformation by binding and inactivating p53 and pRb tumor suppressor proteins. Previous studies have shown that not all of the tumor-suppressive responses were inactivated in SV40-transformed cells; however, the underlying cause ...

  12. Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

    NARCIS (Netherlands)

    Bakker, N.; van Bodegom, P.M.; Poll, W.H.; Boelen, P.; Nat, E.; Rozema, J.; Aerts, R.

    2005-01-01

    The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied

  13. Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

    NARCIS (Netherlands)

    de Bakker, NVJ; van Bodegom, PM; van de Poll, WH; Boelen, P; Nat, E; Rozema, J; Aerts, R

    The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied

  14. Attempts on producing lymphoid cell line from Penaeus monodon by induction with SV40-T and 12S EIA oncogenes.

    Science.gov (United States)

    Puthumana, Jayesh; Prabhakaran, Priyaja; Philip, Rosamma; Singh, I S Bright

    2015-12-01

    In an attempt of in vitro transformation, transfection mediated expression of Simian virus-40 (T) antigen (SV40-T) and transduction mediated expression of Adenovirus type 12 early region 1A (12S E1A) oncogene were performed in Penaeus monodon lymphoid cells. pSV3-neo vector encoding SV40-T oncogene and a recombinant baculovirus BacP2-12S E1A-GFP encoding 12S E1A oncogene under the control of hybrid promoters were used. Electroporation and lipofection mediated transformation of SV40-T in lymphoid cells confirmed the transgene expression by phenotypic variation and the expression of GFP in co-transfection experiment. The cells transfected by lipofection (≥ 5%) survived for 14 days with lower toxicity (30%), whilst on electroporation, most of the cells succumbed to death (60%) and survived cells lived up to 7 days. Transduction efficiency in primary lymphoid cells was more than 80% within 14 days of post-transduction, however, an incubation period of 7 days post-transduction was observed without detectable expression of 12S E1A. High level of oncogenic 12S E1A expression were observed after 14 day post-transduction and the proliferating cells survived for more than 90 days with GFP expression, however, without in vitro transformation and immortalization. The study put forth the requirement of transduction mediated 'specific' oncogene expression along with telomerase activation and epigenetic induction for the immortalization and establishment of shrimp cell line. Copyright © 2015. Published by Elsevier Ltd.

  15. Skyglow effects in UV and visible spectra: Radiative fluxes

    Science.gov (United States)

    Kocifaj, Miroslav; Solano Lamphar, Hector Antonio

    2013-09-01

    Several studies have tried to understand the mechanisms and effects of radiative transfer under different night-sky conditions. However, most of these studies are limited to the various effects of visible spectra. Nevertheless, the invisible parts of the electromagnetic spectrum can pose a more profound threat to nature. One visible threat is from what is popularly termed skyglow. Such skyglow is caused by injudiciously situated or designed artificial night lighting systems which degrade desired sky viewing. Therefore, since lamp emissions are not limited to visible electromagnetic spectra, it is necessary to consider the complete spectrum of such lamps in order to understand the physical behaviour of diffuse radiation at terrain level. In this paper, the downward diffuse radiative flux is computed in a two-stream approximation and obtained ultraviolet spectral radiative fluxes are inter-related with luminous fluxes. Such a method then permits an estimate of ultraviolet radiation if the traditionally measured illuminance on a horizontal plane is available. The utility of such a comparison of two spectral bands is shown, using the different lamp types employed in street lighting. The data demonstrate that it is insufficient to specify lamp type and its visible flux production independently of each other. Also the UV emissions have to be treated by modellers and environmental scientists because some light sources can be fairly important pollutants in the near ultraviolet. Such light sources can affect both the living organisms and ambient environment.

  16. Solar UV Radiation and the Origin of Life On Earth

    Science.gov (United States)

    Heap, S. R.; Lanz, T.; Hubeny, I.; Gaidos, E.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    We have embarked on a program aimed at understanding the atmosphere of the early Earth, because of its importance as a greenhouse, radiation shield and energy source for life. Here, we give a progress report on the first phase of this program to establish the UV radiation from the early Sun. We have obtained ultraviolet spectra (STIS, FUSE, EUVE) of carefully selected nearby, young solar-type stars, which act as surrogates for the early Sun We are making detailed non-LTE analyses of the spectra and constructing models of their photospheres + chromospheres. Once validated, these models will allow us to extrapolate our theoretical spectra to other metallicities and to unobserved spectral regions.

  17. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

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

    Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high......-arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...... (mycorrhiza) or in the biomass of microbes in the soil of the root zone. However, the composition of the soil microbial community was different in the soils under ambient and reduced UV radiation after three treatment years. These results provide new insight into the negative impact of current UV-B fluxes...

  18. Effects of ozone and aerosol on surface UV radiation variability.

    Science.gov (United States)

    Kim, Jhoon; Cho, Hi-Ku; Mok, Jungbin; Yoo, Hee Dong; Cho, Nayeong

    2013-02-05

    Global (direct+diffuse) spectral ultraviolet (UV, 290-363nm) and total ozone measurements made on the roof of the Main Science Building, Yonsei University at Seoul (37.57°, 128.98°E) were analyzed to quantify the effects of ozone and aerosol on the variability of surface erythemal UV (EUV) irradiance. The measurements have been made with a Brewer Spectrophotometer MKIV (SCI-TEC#148) and a Dobson Ozone Spectrophotometer (Beck#123), respectively, during 2004-2008. The overall mean radiation amplification factor, RAF(AOD, SZA) [23,24] due to total ozone (O(3)) (hereafter O(3) RAF) shows that 1% decrease in total ozone results in an increase of 1.18±0.02% in the EUV irradiance with the range of 0.67-1.74% depending on solar zenith angles (SZAs) (40-70°) and on aerosol optical depths (AODs) (UV to ozone (O(3), RAF) was estimated to be about four times higher than to the aerosol (AOD RAF). At the mean O(3), the AOD RAFs(SZA) for both skies appears to be almost independent of SZAs. It is shown that the O(3) RAFs are nearly independent of the sky conditions, whereas the AOD RAFs depend distinctly on the sky conditions with the larger values for all skies. Under cloud free conditions, the overall mean ratio for measured-to-modeled O(3), RAF(AOD, SZA) is 1.13, whereas the ratio for AOD RAF(O(3), SZA) shows 0.82 in the EUV irradiance. Overall, the RAF measurements are corroborated by radiative transfer model calculations under clear-sky conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Dissociation of DNA damage and mitochondrial injury caused by hydrogen peroxide in SV-40 transformed lung epithelial cells

    Directory of Open Access Journals (Sweden)

    Adcock Ian M

    2002-11-01

    Full Text Available Abstract Background Since lung epithelial cells are constantly being exposed to reactive oxygen intermediates (ROIs, the alveolar surface is a major site of oxidative stress, and each cell type may respond differently to oxidative stress. We compared the extent of oxidative DNA damage with that of mitochondrial injury in lung epithelial cells at the single cell level. Result DNA damage and mitochondrial injury were measured after oxidative stress in the SV-40 transformed lung epithelial cell line challenged with hydrogen peroxide (H2O2. Single cell analysis of DNA damage was determined by assessing the number of 8-oxo-2-deoxyguanosine (8-oxo-dG positive cells, a marker of DNA modification, and the length of a comet tail. Mitochondrial membrane potential, ΔΨm, was determined using JC-1. A 1 h pulse of H2O2 induced small amounts of apoptosis (3%. 8-oxo-dG-positive cells and the length of the comet tail increased within 1 h of exposure to H2O2. The number of cells with reduced ΔΨm increased after the addition of H2O2 in a concentration-dependent manner. In spite of a continual loss of ΔΨm, DNA fragmentation was reduced 2 h after exposure to H2O2. Conclusion The data suggest that SV-40 transformed lung epithelial cells are resistant to oxidative stress, showing that DNA damage can be dissociated from mitochondrial injury.

  20. The structure of SV40 large T hexameric helicase in complex with AT-rich origin DNA.

    Science.gov (United States)

    Gai, Dahai; Wang, Damian; Li, Shu-Xing; Chen, Xiaojiang S

    2016-12-06

    DNA replication is a fundamental biological process. The initial step in eukaryotic DNA replication is the assembly of the pre-initiation complex, including the formation of two head-to-head hexameric helicases around the replication origin. How these hexameric helicases interact with their origin dsDNA remains unknown. Here, we report the co-crystal structure of the SV40 Large-T Antigen (LT) hexameric helicase bound to its origin dsDNA. The structure shows that the six subunits form a near-planar ring that interacts with the origin, so that each subunit makes unique contacts with the DNA. The origin dsDNA inside the narrower AAA+ domain channel shows partial melting due to the compression of the two phosphate backbones, forcing Watson-Crick base-pairs within the duplex to flip outward. This structure provides the first snapshot of a hexameric helicase binding to origin dsDNA, and suggests a possible mechanism of origin melting by LT during SV40 replication in eukaryotic cells.

  1. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Krizek, D.T.; Britz, S.J.; Mirecki, R.M. [Climate Stress Laboratory, Beltsville, MD (United States)

    1998-05-01

    The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au) 34 refs.

  2. Complexity analysis of the UV radiation dose time series

    CERN Document Server

    Mihailovic, Dragutin T

    2013-01-01

    We have used the Lempel-Ziv and sample entropy measures to assess the complexity in the UV radiation activity in the Vojvodina region (Serbia) for the period 1990-2007. In particular, we have examined the reconstructed daily sum (dose) of the UV-B time series from seven representative places in this region and calculated the Lempel-Ziv Complexity (LZC) and Sample Entropy (SE) values for each time series. The results indicate that the LZC values in some places are close to each other while in others they differ. We have devided the period 1990-2007 into two subintervals: (a) 1990-1998 and (b) 1999-2007 and calculated LZC and SE values for the various time series in these subintervals. It is found that during the period 1999-2007, there is a decrease in their complexities, and corresponding changes in the SE, in comparison to the period 1990-1998. This complexity loss may be attributed to increased (i) human intervention in the post civil war period (land and crop use and urbanization) and military activities i...

  3. The response of human skin commensal bacteria as a reflection of UV radiation: UV-B decreases porphyrin production.

    Directory of Open Access Journals (Sweden)

    Yanhan Wang

    Full Text Available Recent global radiation fears reflect the urgent need for a new modality that can simply determine if people are in a radiation risk of developing cancer and other illnesses. Ultraviolet (UV radiation has been thought to be the major risk factor for most skin cancers. Although various biomarkers derived from the responses of human cells have been revealed, detection of these biomarkers is cumbersome, probably requires taking live human tissues, and varies significantly depending on human immune status. Here we hypothesize that the reaction of Propionibacterium acnes (P. acnes, a human resident skin commensal, to UV radiation can serve as early surrogate markers for radiation risk because the bacteria are immediately responsive to radiation. In addition, the bacteria can be readily accessible and exposed to the same field of radiation as human body. To test our hypothesis, P. acnes was exposed to UV-B radiation. The production of porphyrins in P. acnes was significantly reduced with increasing doses of UV-B. The porphyrin reduction can be detected in both P. acnes and human skin bacterial isolates. Exposure of UV-B to P. acnes- inoculated mice led to a significant decrease in porphyrin production in a single colony of P. acnes and simultaneously induced the formation of cyclobutane pyrimidine dimers (CPD in the epidermal layers of mouse skin. Mass spectrometric analysis via a linear trap quadrupole (LTQ-Orbitrap XL showed that five peptides including an internal peptide (THLPTGIVVSCQNER of a peptide chain release factor 2 (RF2 were oxidized by UV-B. Seven peptides including three internal peptides of 60 kDa chaperonin 1 were de-oxidized by UV-B. When compared to UV-B, gamma radiation also decreased the porphyrin production of P. acnes in a dose-dependent manner, but induced a different signature of protein oxidation/de-oxidation. We highlight that uncovering response of skin microbiome to radiation will facilitate the development of pre

  4. The Response of Human Skin Commensal Bacteria as a Reflection of UV Radiation: UV-B Decreases Porphyrin Production

    Science.gov (United States)

    Wang, Yanhan; Zhu, Wenhong; Shu, Muya; Jiang, Yong; Gallo, Richard L.; Liu, Yu-Tsueng; Huang, Chun-Ming

    2012-01-01

    Recent global radiation fears reflect the urgent need for a new modality that can simply determine if people are in a radiation risk of developing cancer and other illnesses. Ultraviolet (UV) radiation has been thought to be the major risk factor for most skin cancers. Although various biomarkers derived from the responses of human cells have been revealed, detection of these biomarkers is cumbersome, probably requires taking live human tissues, and varies significantly depending on human immune status. Here we hypothesize that the reaction of Propionibacterium acnes (P. acnes), a human resident skin commensal, to UV radiation can serve as early surrogate markers for radiation risk because the bacteria are immediately responsive to radiation. In addition, the bacteria can be readily accessible and exposed to the same field of radiation as human body. To test our hypothesis, P. acnes was exposed to UV-B radiation. The production of porphyrins in P. acnes was significantly reduced with increasing doses of UV-B. The porphyrin reduction can be detected in both P. acnes and human skin bacterial isolates. Exposure of UV-B to P. acnes- inoculated mice led to a significant decrease in porphyrin production in a single colony of P. acnes and simultaneously induced the formation of cyclobutane pyrimidine dimers (CPD) in the epidermal layers of mouse skin. Mass spectrometric analysis via a linear trap quadrupole (LTQ)-Orbitrap XL showed that five peptides including an internal peptide (THLPTGIVVSCQNER) of a peptide chain release factor 2 (RF2) were oxidized by UV-B. Seven peptides including three internal peptides of 60 kDa chaperonin 1 were de-oxidized by UV-B. When compared to UV-B, gamma radiation also decreased the porphyrin production of P. acnes in a dose-dependent manner, but induced a different signature of protein oxidation/de-oxidation. We highlight that uncovering response of skin microbiome to radiation will facilitate the development of pre-symptomatic diagnosis

  5. Inhibition of multidrug resistance by SV40 pseudovirion delivery of an antigene peptide nucleic acid (PNA in cultured cells.

    Directory of Open Access Journals (Sweden)

    Benjamin Macadangdang

    Full Text Available Peptide nucleic acid (PNA is known to bind with extraordinarily high affinity and sequence-specificity to complementary nucleic acid sequences and can be used to suppress gene expression. However, effective delivery into cells is a major obstacle to the development of PNA for gene therapy applications. Here, we present a novel method for the in vitro delivery of antigene PNA to cells. By using a nucleocapsid protein derived from Simian virus 40, we have been able to package PNA into pseudovirions, facilitating the delivery of the packaged PNA into cells. We demonstrate that this system can be used effectively to suppress gene expression associated with multidrug resistance in cancer cells, as shown by RT-PCR, flow cytometry, Western blotting, and cell viability under chemotherapy. The combination of PNA with the SV40-based delivery system is a method for suppressing a gene of interest that could be broadly applied to numerous targets.

  6. Cellular ras gene activity is required for full neoplastic transformation by the large tumor antigen of SV40.

    Science.gov (United States)

    Raptis, L; Brownell, H L; Corbley, M J; Wood, K W; Wang, D; Haliotis, T

    1997-08-01

    To investigate the role of the cellular ras gene product in neoplastic transformation by the SV40 large tumor antigen (SVLT), murine C3H10T1/2 cells were rendered deficient in Ras activity by transfection with inducible or constitutive antisense ras gene constructs or through the introduction of the dominant-negative mutant, ras(asn17). Consistent with previous results, SVLT-induced morphological transformation was unaffected by the down-regulation of c-ras gene product activity. On the other hand, colony formation in soft agar and tumorigenicity in nude mice were drastically reduced in c-Ras-deficient cells. In addition, SVLT expression in C3H10T1/2 cells led to increased c-Ras activity, as determined by an increase in the Ras-bound GTP/GTP + GDP ratio. These results suggest that c-Ras is required for full neoplastic transformation by SVLT.

  7. Solar radiation (PAR, UV-A, UV-B) penetration in a shallow maturation pond operating in a tropical climate.

    Science.gov (United States)

    Dias, Daniel F C; von Sperling, Marcos

    2017-07-01

    Solar radiation is considered the primary route for disinfection of pathogenic bacteria in maturation ponds. There is scarce information on depth profiling and attenuation of photosynthetically active radiation (PAR), UV-A and UV-B in shallow maturation ponds operating in tropical climates. Measurements of solar irradiance of the three wavelength ranges, together with turbidity, have been acquired from different depths for over 1 year in a shallow maturation pond (44 cm of depth) operating in Brazil. UV-A and UV-B were still detected at 10 cm from the surface, but from 15 cm both were undetectable. PAR was still detected at 30 cm of depth. Irradiation attenuation showed to be related to turbidity. Attenuation coefficients were calculated and simple models without turbidity (traditional structure) or including log 10 of turbidity are proposed for predicting PAR irradiance attenuation as a function of depth.

  8. Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

    Directory of Open Access Journals (Sweden)

    Jeanette Beber de Souza

    2015-01-01

    Full Text Available The individual methods of disinfection peracetic acid (PAA and UV radiation and combined process PAA/UV in water (synthetic and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater, and coliphages (such as virus indicators. Under the experimental conditions investigated, doses of 2, 3, and 4 mg/L of PAA and contact time of 10 minutes and 60 and 90 s exposure to UV radiation, the results indicated that the combined method PAA/UV provided superior efficacy when compared to individual methods of disinfection.

  9. Bystander Effect Induced by UV Radiation; why should we be interested? 

    Directory of Open Access Journals (Sweden)

    Maria Widel

    2012-11-01

    Full Text Available The bystander effect, whose essence is an interaction of cells directly subjected to radiation with adjacent non-subjected cells, via molecular signals, is an important component of ionizing radiation action. However, knowledge of the bystander effect in the case of ultraviolet (UV radiation is quite limited. Reactive oxygen and nitrogen species generated by UV in exposed cells induce bystander effects in non-exposed cells, such as reduction in clonogenic cell survival and delayed cell death, oxidative DNA damage and gene mutations, induction of micronuclei, lipid peroxidation and apoptosis. Although the bystander effect after UV radiation has been recognized in cell culture systems, its occurrence in vivo has not been studied. However, solar UV radiation, which is the main source of UV in the environment, may induce in human dermal tissue an inflammatory response and immune suppression, events which can be considered as bystander effects of UV radiation. The oxidative damage to DNA, genomic instability and the inflammatory response may lead to carcinogenesis. UV radiation is considered one of the important etiologic factors for skin cancers, basal- and squamous-cell carcinomas and malignant melanoma. Based on the mechanisms of actions it seems that the UV-induced bystander effect can have some impact on skin damage (carcinogenesis?, and probably on cells of other tissues. The paper reviews the existing data about the UV-induced bystander effect and discusses a possible implication of this phenomenon for health risk. 

  10. Design and Fabrication of an Integrated Circuit for Monitoring UV Radiation for Health Physics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nazififard, Mohammad; Faghihi, Reyhaneh [Kashan Univ., Kashan (Iran, Islamic Republic of); Champiri, Afshin Mahmoudieh [Shahid Chamran Univ., Ahwaz (Iran, Islamic Republic of); Norov, Enkhbat [POSTECH, Pohang (Korea, Republic of); Suh, Kune Y. [Seoul National Univ., Seoul (Korea, Republic of)

    2014-05-15

    A particularly important term in the clinical photobiology is the standard erythemal dose (SED), which is a measure of the erythemal effectiveness of a UV exposure. However, both the quality and quantity of the UV radiation are important factors for the UV monitoring. This paper aims to introduce and investigate a UV radiation meter in order to establish its applicability for non-ionizing radiation detection. The ultraviolet (UV) radiation is part of the electromagnetic spectrum. The biological effects of UV radiation vary enormously with wavelength and for this reason the UV spectrum is further divided into three regions: UVA, UVB, and UVC. There is increasing evidence that long wave UV radiation plays a vital role in the pathogenesis of photo-dermatoses such as polymorphous light eruption as well as photo-aging. UVA, UVB, and UVC can all damage collagen fibers and, therefore, accelerate aging of the skin. Both UVA and UVB destroy vitamin A in the skin, which may cause further damage. The quantities of the UV radiation are generally expressed using the radiometric terminology.

  11. Characterization of Actin Filament Dynamics during Mitosis in Wheat Protoplasts under UV-B Radiation

    Science.gov (United States)

    Chen, Huize; Han, Rong

    2016-01-01

    Enhanced ultraviolet-B (UV-B) radiation is caused by the thinning ozone and affects photosynthesis and crop yield. Recently, UV-B radiation has been considered as an environmental signal that regulates plant growth. Elucidating the downstream effectors in UV-B-triggered pathways is of particular interest. Previous studies have shown that actin filaments (AFs) play many roles during cell physiological processes. However, the underlying response of AFs to UV-B radiation remains unclear. In this study, wheat protoplasts were isolated from 7-d-old leaves. The dynamics of AFs during mitosis were observed under different treatments. The protoplasts were treated with UV-B radiation, cytochalasin B (CB) and jasplakinolide (JAS). Ph-FITC labelling results revealed typical actin filament structures in the control group; AFs were rearranged under UV-B radiation. AFs polymerized into bundles during interphase, the preprophase band (PPB) structure was destroyed during prophase, and the AFs gathered into plaques during metaphase in response to UV-B radiation. During anaphase and telophase, the distribution of AFs was dispersed. Pharmacologic experiments revealed that CB induced apoptosis and JAS induced nuclear division without cytokinesis in wheat protoplasts. These results indicated that AFs respond to UV-B radiation during mitosis, supplying evidence of UV-B signal transduction in plants. PMID:26823006

  12. Bystander effect induced by UV radiation; why should we be interested?

    Science.gov (United States)

    Widel, Maria

    2012-11-14

    The bystander effect, whose essence is an interaction of cells directly subjected to radiation with adjacent non-subjected cells, via molecular signals, is an important component of ionizing radiation action. However, knowledge of the bystander effect in the case of ultraviolet (UV) radiation is quite limited. Reactive oxygen and nitrogen species generated by UV in exposed cells induce bystander effects in non-exposed cells, such as reduction in clonogenic cell survival and delayed cell death, oxidative DNA damage and gene mutations, induction of micronuclei, lipid peroxidation and apoptosis. Although the bystander effect after UV radiation has been recognized in cell culture systems, its occurrence in vivo has not been studied. However, solar UV radiation, which is the main source of UV in the environment, may induce in human dermal tissue an inflammatory response and immune suppression, events which can be considered as bystander effects of UV radiation. The oxidative damage to DNA, genomic instability and the inflammatory response may lead to carcinogenesis. UV radiation is considered one of the important etiologic factors for skin cancers, basal- and squamous-cell carcinomas and malignant melanoma. Based on the mechanisms of actions it seems that the UV-induced bystander effect can have some impact on skin damage (carcinogenesis?), and probably on cells of other tissues. The paper reviews the existing data about the UV-induced bystander effect and discusses a possible implication of this phenomenon for health risk. 

  13. Antiradiation UV Vaccine: UV Radiation, Biological effects, lesions and medical management - immune-therapy and immune-protection.

    Science.gov (United States)

    Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

    Key Words: Ultraviolet radiation,Standard Erythema Dose(SED), Minimal Erythema Dose(MED), Sun Burns, Solar Dermatitis, Sun Burned Disease, DNA Damage,Cell Damage, Antiradiation UV Vaccine, Immune-Prophylaxis of Sun Burned Diseases, Immune-Prophylaxis of Sun Burns, Immune-Therapy of Sun-Burned Disease and Sun Burns,Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), Toxic Epidermal Necrolysis(TEN). Introduction: High doses of UV generated by solar source and artificial sources create an exposure of mammals and other species which can lead to ultraviolet(UV)radiation- associated disease (including erythema, epilation, keratitis, etc.). UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm with 100 nm having been chosen arbitrarily as the boundary between non-ionizing and ionizing radiation, however EMR is a spectrum and UV can produce molecular ionization. UV radiation is conventionally categorized into 3 areas: UV-A (>315-400 nm),UV-B (>280-315 nm)and UV-C (>100-280 nm) [IARC,Working Group Reports,2005] An important consequence of stratospheric ozone depletion is the increased transmission of solar ultraviolet (UV)radiation to the Earth's lower atmosphere and surface. Stratospheric ozone levels have been falling, in certain areas, for the past several decades, so current surface ultraviolet-B (UV-B) radiation levels are thought to be close to their modern day maximum. [S.Madronich et al.1998] Overexposure of ultraviolet radiation a major cause of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) { collectively referred to as “non-melanoma" skin cancer (NMSC) and melanoma as well, with skin cancers being the most common cancer in North America. [Armstrong et al. 1993, Gallagher et al. 2005] Methods and Experimental Design: Our experiments and testing of a novel UV “Antiradiation Vaccine” have employed a wide variety of laboratory animals which include : Chinchilla

  14. DJ-1, an oncogene and causative gene for familial Parkinson's disease, is essential for SV40 transformation in mouse fibroblasts through up-regulation of c-Myc.

    Science.gov (United States)

    Kim, Yun Chul; Kitaura, Hirotake; Iguchi-Ariga, Sanae M M; Ariga, Hiroyoshi

    2010-09-24

    Simian virus 40 (SV40) is a tumor virus and its early gene product large T-antigen (LT) is responsible for the transforming activity of SV40. Parkinson's disease causative gene DJ-1 is also a ras-dependent oncogene, but the mechanism of its oncogene function is still not known. In this study, we found that there were no transformed foci when fibroblasts from DJ-1-knockout mice were transfected with LT. We also found that DJ-1 directly bound to LT and that the expression level of c-Myc in transformed cells was parallel to that of DJ-1. These findings indicate that DJ-1 is essential for SV40 transformation. Copyright © 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  15. Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    Science.gov (United States)

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions...

  16. Effects of ultraviolet-B (UV-B) radiation on two cryptogamic plants ...

    African Journals Online (AJOL)

    Chlorofluorocarbons are mainly responsible for the depletion of stratospheric ozone layer which results in increase of UV-B radiation on earth's environment and causing adverse effects on flora. In the present study we have investigated the effect of ultraviolet-B (UV-B) radiation on two cryptogamic plants (Xanthoria elegans ...

  17. The effects of UV-B radiation on European heathland species

    DEFF Research Database (Denmark)

    Björn, Lars O.; Callaghan, T. V.; Johnsen, Ib

    1997-01-01

    The effects of enhanced UV-B radiation on three examples of European shrub-dominated vegetation were studied in situ. The experiments were in High Arctic Greenland, northern Sweden and Greece, and at all sites investigated the interaction of enhanced UV-B radiation (simulating a 15% reduction in ...

  18. Effects of ultraviolet-B (UV-B) radiation on two cryptogamic plants ...

    African Journals Online (AJOL)

    rudra

    DNA damage and photosynthetic performance in the. Antarctic terrestrial alga Prasiola crispa sp. Antarctica (Chlorophyta) under manipulated UV-B radiation. J. Phycol., 37: 459-467. Lud D, Huiskes A, Moerdijk T, Rozema J (2001b). The effects of altered levels of UV-B radiation on an Antarctic grass and lichen. Plant Ecol.,.

  19. THE ACTION OF UV RADIATION ON MITOTIC INDEX AND MITOTIC DIVISION PHASES AT PHASEOLUS VULGARIS L

    Directory of Open Access Journals (Sweden)

    Csilla Iuliana Bara

    2005-08-01

    Full Text Available In this work, damaging effects of UV radiations on bean Phaseolus vulgaris L. plantule root tips were investigated. Our study proves that by bean plants, the decrease of cell division frequency appears to be part of protection mechanism against especially the short waved UV radiation, with variations depending on cultivar.

  20. Validation of the Austrian forecast model for solar, biologically effective UV radiation-UV index for Vienna

    Science.gov (United States)

    Schmalwieser, Alois W.; Schauberger, Günther

    2000-11-01

    Since October 1995, a daily forecast of the UV index, as the irradiance of the biologically effective ultraviolet radiation, for the next day is published for Austria, Europe, and world wide. The Austrian forecast model as well as the input parameters are described. By connecting the UV index with the sensitivity of the photobiological skin types, a recommendation is given to select an appropriate sun protection factor of a sunscreen to avoid overexposure of the skin. The validation of the Austrian forecast model is done by measurements of the biologically effective ultraviolet radiation collected between July 1996 and July 1998 at Vienna (48°N, 16°E), Austria. The forecast quality is evaluated by comparing the Austrian model with two statistical models used in Canada and the Netherlands. By using the underestimation of the UV index as criteria in the sense of radiation protection, the Austrian model shows a 12% underestimation over the whole year.

  1. Interactive effects of solar UV radiation and climate change on biogeochemical cycling.

    Science.gov (United States)

    Zepp, R G; Erickson, D J; Paul, N D; Sulzberger, B

    2007-03-01

    This report assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are often linked to concurrent exposure to UV-A radiation (315-400 nm), which is influenced by global climate change. These interactions involving UV radiation (the combination of UV-B and UV-A) are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B radiation has significant effects on the terrestrial biosphere with implications for the cycling of carbon, nitrogen and other elements. The cycling of carbon and inorganic nutrients such as nitrogen can be affected by UV-B-mediated changes in communities of soil organisms, probably due to the effects of UV-B radiation on plant root exudation and/or the chemistry of dead plant material falling to the soil. In arid environments direct photodegradation can play a major role in the decay of plant litter, and UV-B radiation is responsible for a significant part of this photodegradation. UV-B radiation strongly influences aquatic carbon, nitrogen, sulfur and metals cycling that affect a wide range of life processes. UV-B radiation changes the biological availability of dissolved organic matter to microorganisms, and accelerates its transformation into dissolved inorganic carbon and nitrogen, including carbon dioxide and ammonium. The coloured part of dissolved organic matter (CDOM) controls the penetration of UV radiation into water bodies, but CDOM is also photodegraded by solar UV radiation. Changes in CDOM influence the penetration of UV radiation into water bodies with major consequences for aquatic biogeochemical processes. Changes in aquatic primary productivity and decomposition due to climate-related changes in circulation and nutrient supply occur concurrently with

  2. Risks of increased UV-B radiation for phytoplankton; Risiken erhoehter UV-B-Strahlung auf Phytoplankton

    Energy Technology Data Exchange (ETDEWEB)

    Haeder, D.P. [Inst. fuer Botanik und Pharmazeutische Biologie, Erlangen (Germany); Gerber, S. [Inst. fuer Botanik und Pharmazeutische Biologie, Erlangen (Germany)

    1994-03-01

    The BayFORKLIM programme focussed on two main aspects of the risks of increased UV-B radiation for phytoplankton. The first involved laboratory studies on wild organisms which, unlike laboratory organisms, are adapted to the present climate and in particular to today`s intensities of UV-B radiation. The studies were performed on euglena sanguinea taken from an algal bloom. These algal orient themselves exclusively by positive phototaxis in their habitat, that is, they move towards the water surface. Their red colour derives from haematochrome, a mixture of carotinoids which probably serve as protective prigments. Artificial, intensified UV-B radiation impairs the orientation of these organisms, reduces their swimming speed, and bleaches their chlorophylla. Exposition time until impairment is the same as for laboratory-bred, `more sensitive` organisms. Beside the laboratory work, field studies were performed on algal at different altitudes, namely in Erlangen and on the Zugspitze, where they were exposed to natural, `above-normal` UV-B radiation. These experiments yielded a higher pigment bleaching rate on the Zugspitze than in Erlangen for all three species under study. Motility likewise decreased faster on the Zugspitze than in Erlangen. Filters that absorb UV-B radiation protect the algal to some degree: Bleaching and immotility are delayed. (orig.) [Deutsch] Die Risiken erhoehter UV-B-Strahlung fuer Phytoplankton wurden im Rahmen des BayFORKLIM unter 2 Hauptaspekten betrachtet: Zum einen wurden Untersuchungen an Freilandorganismen vorgenommen, die - anders als Labororganismen - an die heutigen Klimabedingungen und insbesondere an die herrschenden UV-B-Bestrahlungsstaerken angepasst sind. Dazu wurden Untersuchungen an Euglena sanguinea aus einer Algenbluete durchgefuehrt. Die Algen orientieren sich in ihrem Habitat ausschliesslich durch positive Phototaxis, die sie an die Gewaesseroberflaeche bringt. Sie sind durch Haematochrom, einer Mischung aus Carotinoiden

  3. Effects of modified UV-B radiation on terrestrial ecosystems; Auswirkungen veraenderter UV-B-Strahlung auf terrestrische Oekosysteme

    Energy Technology Data Exchange (ETDEWEB)

    Tevini, M. [Karlsruhe Univ. (T.H.) (Germany). Botanisches Inst. 2

    1994-10-01

    The author describes the effects of anthropogenically modified UV-B radiation on plants and aquatic ecosystems. The modified radiation may cause reduced growth of leaves and shoots, partial reduction of the photosynthesis activity, and reduced biomass production (i.e. a loss of yield). Although the UV damage may be compensated to a certain degree by a synthesis of protective pigments (cinnamonic acids and flavonoids) or by UV repair mechanisms via the enyzme photolyase, the upper limit of this adapability seems to have already been reached. One frequently observed effect of the increase in UV radiation in aquatic systems is the loss of phytoplancton biomass by 6 - 10%.Since phytoplancton is the basis of the marine food chain, this may have long-term effects on the number and distribution of species and on fish protein for the human diet. Further, the loss of biomass causes a reduction of carbon dioxide fixation, which may have consequences for the global carbon cycle. (orig.) [Deutsch] Der Autor beschreibt die Auswirkungen anthropogen veraenderter UV-B-Strahlung auf Pflanzen und aquatische Oekosysteme. Durch die veraenderte Strahlung kann es zu vermindertem Blatt- und Sprosswachstum, zur partiellen Reduktion der Photosyntheseaktivitaet und zu verringerter Biomasseproduktion, d.h. zu einem Ertragsverlust kommen. Die UV-Schaedigung kann zwar durch die Synthese von Schutzpigmenten (Zimtsaeuren und Flavonoide) oder durch UV-Reparaturmechanismen ueber das Enzym Photolyase in gewissem Masse kompensiert werden, die obere Grenze dieser Adaptationsfaehigkeit scheint aber bereits erreicht zu sein. Ein beobachteter Effekt des UV-Strahlungsanstiegs in aquatischen Systemen ist der Verlust der Phytoplankton-Biomasse um 6% - 10%. Da das Phytoplankton die Grundlage der marinen Nahrungskette bildet, sind Rueckwirkungen auf die Artenzusammensetzung und die menschliche Ernaehrung mit Fischprotein moeglich. Weiterhin fuehrt der Verlust an Biomasse zu einer Reduzierung der

  4. Response of marine microalgae, heterotrophic bacteria and their relationship to enhanced UV-B radiation

    Science.gov (United States)

    Zhou, Wenli; Tang, Xuexi; Xiao, Hui; Wang, You; Wang, Renjun

    2009-03-01

    Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microalgae, heterotrophic bacteria and the interaction between them are discussed. The effects on marine microalgae have been proved to occur at molecular, cellular and population levels. Enhanced UV-B radiation increases microalgal flavonoid content but decreases their chlorophyll content and photosynthesis rate; this radiation induces genetic change and results in DNA damage and change of protein content. There have been fewer studies on the effects of UV-B radiation on marine heterotrophic bacteria. Establishment of a microalgal ecological dynamic model at population and community levels under UV-B radiation has gradually become a hotspot. The effects of enhanced UV-B radiation on microalgae communities, heterotrophic bacterial populations and interaction between them will become a focus in the near future. This paper will make an overview on the studies concerning the effects of enhanced UV-B radiation on marine microalgae and heterotrophic bacteria and the interaction between them.

  5. Risks of increased UV-B radiation for humans; Risiken erhoehter UV-B-Strahlung fuer den Menschen

    Energy Technology Data Exchange (ETDEWEB)

    Przybilla, B. [Muenchen Univ. (Germany). Dermatologische Klinik und Poliklinik; Eberlein-Koenig, B. [Muenchen Univ. (Germany). Dermatologische Klinik und Poliklinik; Bergner, T. [Muenchen Univ. (Germany). Dermatologische Klinik und Poliklinik

    1994-03-01

    If not compensated in any way, depletion of the stratospheric ozone layer leads to an increase of UV-B radiation at the earth`s surface, especially towards the short-wave range, which is biologically the more active. The most concerning effect here is that of UV-B induced skin reactions, in particular malignant skintumors (malignant melanoma, spinocellular carcinoma, basalioma), whose incidence is expected to increase in future. As some photoreactions can be inhibited or enhanced also by radiation outside their action spectrum, it is possible for changes in solar spectral radiation flux density to influence photo-induced reactions that are driven at wavelengths outside the UV-B range. The authors have performed studies for developing methods of quantifying individual UV sensitivity. In vitro studies have shown that UV-A dependent photoreactions can be partly inhibited by UV-B. A number of drugs, as well as sulphites, which are used as preservatives amongst other things, have been shown to have phototoxic properties that may be relevant to photocarcinogenesis. Irradiation tests on cell cultures for different UV-B ranges have shown that irradiation at shorter wavelengths leads to a stronger release of proinflammatory cytokines that ar longer wavelengths with the same dose. Altogether it can be said that despite compelling theoretical evidence it is not easily possible to predict the actual consequences of an increase in particular of short-wave UV-B radiation at the earth`s surface. The assumed effects must be examined individually by appropriate methods. (orig.) [Deutsch] Eine Abnahme der stratosphaerischen Ozonschicht fuehrt, sofern keine anderweitige Kompensation erfolgt, auf der Erdoberflaeche zu einer Zunahme der UV-B-Strahlung insbesondere im kuerzerwelligen Bereich, die im Vergleich zu laengerwelligen UV-B-Anteilen biologisch ueberproportional wirksam ist. Dies waere vor allem fuer UV-B-induzierte Hautreaktionen von Bedeutung, wobei insbesondere eine Zunahme

  6. UV-B radiation and photosynthetic irradiance acclimate eggplant for outdoor exposure

    Science.gov (United States)

    Latimer, J. G.; Mitchell, C. A.; Mitchell, G. A.

    1987-01-01

    Treatment of greenhouse-grown eggplant (Solanum melongena L. var. esculentum Nees. 'Burpee's Black Beauty') seedlings with supplemental photosynthetically active radiation from cool-white fluorescent lamps increased growth of plants subsequently transferred outdoors relative to growth of plants that received no supplemental radiation or were shaded to 45% of solar irradiation in the greenhouse before transfer outdoors. Eggplant seedlings transferred outdoors were placed under plastic tarps either to provide relative protection from solar ultraviolet-B (UV-B) radiation (280-315 nm) using Mylar film or to allow exposure to UV-B using cellulose acetate. Protection of seedlings from UV-B radiation resulted in greater leaf expansion than for UV-B-exposed seedlings, but no change in leaf or shoot dry weight occurred after 9 days of treatment. Specific leaf weight increased in response to UV-B exposure outdoors. Exposure of eggplant to UV-B radiation from fluorescent sunlamps in the greenhouse also decreased leaf expansion and leaf and shoot dry weight gain after 5 days of treatment. However, there were no differences in leaf or shoot dry weight relative to control plants after 12 days of UV-B treatment, indicating that UV-B treated plants had acclimated to the treatment and actually had caught up with non-UV-B-irradiated plants in terms of growth.

  7. Risks of increased UV-B radiation: higher plants; Risiken erhoehter UV-B-Strahlung: Hoehere Pflanzen

    Energy Technology Data Exchange (ETDEWEB)

    Rau, W. [Muenchen Univ. (Germany). Botanisches Inst.; Hofmann, H. [Muenchen Univ. (Germany). Botanisches Inst.

    1994-03-01

    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) [Deutsch] Die Fragestellung, die im Rahmen des Bayerischen Klimaforschungsprogramms (BayFORKLIM) bearbeitet wurde, ist folgende: Die UV-B-Strahlung nimmt mit der Hoehe ueber dem Meeresspiegel zu; sind deshalb Pflanzenarten, die bevorzugt in alpinen Habitaten vorkommen, durch ihre genetische Konstitution - moeglicherweise durch Selektion erworben - weniger UV

  8. Internal pigment cells respond to external UV radiation in frogs.

    Science.gov (United States)

    Franco-Belussi, Lilian; Nilsson Sköld, Helen; de Oliveira, Classius

    2016-05-01

    Fish and amphibians have pigment cells that generate colorful skins important for signaling, camouflage, thermoregulation and protection against ultraviolet radiation (UVR). However, many animals also have pigment cells inside their bodies, on their internal organs and membranes. In contrast to external pigmentation, internal pigmentation is remarkably little studied and its function is not well known. Here, we tested genotoxic effects of UVR and its effects on internal pigmentation in a neotropical frog, Physalaemus nattereri We found increases in body darkness and internal melanin pigmentation in testes and heart surfaces and in the mesenterium and lumbar region after just a few hours of UVR exposure. The melanin dispersion in melanomacrophages in the liver and melanocytes in testes increased after UV exposure. In addition, the amount of melanin inside melanomacrophages cells also increased. Although mast cells were quickly activated by UVR, only longer UVR exposure resulted in genotoxic effects inside frogs, by increasing the frequency of micronuclei in red blood cells. This is the first study to describe systemic responses of external UVR on internal melanin pigmentation, melanomacrophages and melanocytes in frogs and thus provides a functional explanation to the presence of internal pigmentation. © 2016. Published by The Company of Biologists Ltd.

  9. Bypass of a site-specific cis-Syn thymine dimer in an SV40 vector during in vitro replication by HeLa and XPV cell-free extracts.

    Science.gov (United States)

    Ensch-Simon, I; Burgers, P M; Taylor, J S

    1998-06-02

    The key step in skin cancer induction by UV light is thought to be the mutagenic DNA synthesis past a DNA photoproduct in a proto-oncogene or tumor suppressor gene. To investigate this critical step, we have constructed an SV40 vector containing a cis-syn thymine dimer, the major DNA photoproduct induced by UVB light, within an AseI site at a location that would initially be replicated by leading strand synthesis. When the dimer-containing SV40 vector was incubated with cell-free HeLa extracts in the presence of TAg, and then digested with AseI, a 2325 bp fragment corresponding to inhibition of cleavage at the dimer site was observed, suggesting that the dimer had terminated synthesis and/or had been bypassed. When the reaction was limited to one round of replication and the products of restriction enzyme digestion were examined by denaturing gel electrophoresis, bands corresponding to both termination and bypass were observed in roughly a one-to-one ratio. Whereas increasing the dNTP concentration from 10 microM to 1 mM increased the ratio of bypass to termination from 0.6 to 2.6, it had no effect on the site of termination, which occurred exclusively one nucleotide before the dimer. Experiments in which dGTP was held constant at 25 microM and various combinations of the remaining nucleotides were raised from 25 microM to 1 mM showed substantial increases in the bypass-to-termination ratio, with the greatest effect seen for raising all three nucleotides to 1 mM. Replication by primary fibroblast XPV extracts was also investigated and found to be greatly stimulated by rhRPA, whereas the stimulatory effect for HeLa cell extracts was variable. In the presence of rhRPA, the XPV extracts were also found to bypass the cis-syn dimer, which contrasts with a recent report that could not detect dimer bypass in SV40 transformed XPV extracts in the absence of added replication factors [Cordeiro-Stone, M., et al. (1997) J. Biol. Chem. 272, 13945-13954].

  10. 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.

  11. Are the surgeons safe during UV-A radiation exposure in collagen cross-linking procedure?

    Science.gov (United States)

    Shetty, Rashmi; Shetty, Rohit; Mahendradas, Padmamalini; Shetty, Bhujang K

    2012-02-01

    To quantify the effect of scattered UV-A radiation used in the collagen cross-linking (CXL) procedure and the amount of radiation reaching the surgeon and the surrounding area and to estimate the dampening effect by various protective devices. In this case series, 3 patients [aged 25-30 (±2.5) years] with keratoconus underwent a CXL procedure with UV-A light and riboflavin. Irradiance was measured using a spectrometer (Model USB2000; Ocean Optics, Inc) for various distances from the source, at various angles, and for different durations of radiation. The spectrometer was also used to measure the dampening effect produced by gown, latex gloves, and UV-protective glasses. Maximum UV-A radiation (1.4 × 10(-9) mW/cm(2)) was measured at 2 cm from the limbus, when the probe was held at a 45-degree angle to the floor. UV-A radiation reaching the surgeon's eye and the abdomen was 3.403 × 10(-11) and 2.36 × 10(-11) mW/cm(2), respectively. Gown, latex gloves, and UV-protective glasses showed dampening effects of 99.58%, 95.01%, and 99.73%, respectively. CXL appears to be a safe procedure with respect to UV-A radiation exposure to the surgeon. Further safety can be ensured by UV-protective devices.

  12. 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

  13. 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

  14. The fascinating diatom frustule—can it play a role for attenuation of UV radiation?

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Lenau, Torben Anker; Lundholm, Nina

    2016-01-01

    size range as wave lengths of visible and ultraviolet (UV) light. This has prompted research into the possible role of the frustule in mediating light for the diatoms’ photosynthesis as well as into possible photonic applications of the diatom frustule. One of the possible biological roles, as well...... as area of potential application, is UV protection. In this review, we explore the possible adaptive value of the silica frustule with focus on research on the effect of UV radiation ondiatoms. We also explore the possible effect of the frustules on UV radiation, from a theoretical, biological...

  15. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

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

    Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high-arctic regi......Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high...

  16. UV-A radiation effects on higher plants: Exploring the known unknown.

    Science.gov (United States)

    Verdaguer, Dolors; Jansen, Marcel A K; Llorens, Laura; Morales, Luis O; Neugart, Susanne

    2017-02-01

    Ultraviolet-A radiation (UV-A: 315-400nm) is a component of solar radiation that exerts a wide range of physiological responses in plants. Currently, field attenuation experiments are the most reliable source of information on the effects of UV-A. Common plant responses to UV-A include both inhibitory and stimulatory effects on biomass accumulation and morphology. UV-A effects on biomass accumulation can differ from those on root: shoot ratio, and distinct responses are described for different leaf tissues. Inhibitory and enhancing effects of UV-A on photosynthesis are also analysed, as well as activation of photoprotective responses, including UV-absorbing pigments. UV-A-induced leaf flavonoids are highly compound-specific and species-dependent. Many of the effects on growth and development exerted by UV-A are distinct to those triggered by UV-B and vary considerably in terms of the direction the response takes. Such differences may reflect diverse UV-perception mechanisms with multiple photoreceptors operating in the UV-A range and/or variations in the experimental approaches used. This review highlights a role that various photoreceptors (UVR8, phototropins, phytochromes and cryptochromes) may play in plant responses to UV-A when dose, wavelength and other conditions are taken into account. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Effects of ozone depletion and UV-B radiation on humans and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, K.R. [Guelph Univ., ON (Canada). Centre for Toxicology

    2008-03-15

    This paper summarized current research related to the effects of ultraviolet (UV-B) radiation on human health and the environment. Effects included direct responses in human as well as effects on biogeochemistry and the environmental cycling of substances. UV radiation has many harmful effects on the skin, eyes, and immune systems of humans. Skin cancer is a leading cause of death among fair-skinned populations exposed to UV radiation. The role of UV radiation in cataract formation was discussed, as well as issues related to the suppression of immune responses. The link between sunlight exposure and vitamin D levels in human populations was examined. The effects of UV radiation on terrestrial and aquatic ecosystems were reviewed. Issues related to biogeochemistry and atmospheric processes were discussed. The review suggested that changes in the intensity of solar UV radiation due to ozone depletion will have important repercussions for all organisms on the planet. It was concluded that the combined effects of UV-B radiation and climate change will not be easy to predict. 201 refs., 4 figs.

  18. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  19. Radiation damage of all-silica fibers in the UV region

    Science.gov (United States)

    Gombert, Joerg; Ziegler, M.; Assmus, J.; Klein, Karl-Friedrich; Nelson, Gary W.; Clarkin, James P.; Pross, H.; Kiefer, J.

    1999-04-01

    Since several years, UVI-fibers having higher solarization- resistance are well known stimulating new fiber-optic applications in the UV-region below 250 nm. Besides the description of the improved transmission properties of UV- light from different UV-sources, the mechanisms of improvement have been discussed in detail. The UV-defects, mainly the E'- center with the UV-absorption band around 215 nm, were passivated by using hydrogen-doping. Besides DUV-light, ionizing radiation like Gamma-radiation or X-rays can create similar defects in the UV-region. In the past, the radiation- damage in the UV-region was studied on silica bulk samples: again, E'-centers were generated. Up to now, no UV- transmission through a 1 m long fiber during or after Gamma- radiation had been observed. However, the hydrogen in the UVI- fibers behaves the same for Gamma-irradiation, leading to a passivation of the radiation-induced defects and an improved transmission in the UV-C region below 250 nm. On this report, the influence of total dose and fiber diameter on the UV- damage after irradiation will be described and discussed. In addition, we will include annealing studies, with and without UV-light. Based on our results, the standard process of Gamma- sterilization with a total dose of approx. 2 Mrad can be used for UVI-fibers resulting in a good UV-transmission below 320 nm. Excimer-laser light at 308 nm (XeCl) and 248 nm (KrF) and deuterium-lamp light with the full spectrum starting at 200 nm can also be transmitted.

  20. The Prognostic Role and Relationship between E2F1 and SV40 in Diffuse Large B-Cell Lymphoma of Egyptian Patients

    Directory of Open Access Journals (Sweden)

    Rehab M. Samaka

    2015-01-01

    Full Text Available Diffuse large B-cell lymphoma (DLBCL is the most common type of lymphomas worldwide. The pathogenesis of lymphomas is not yet well understood. SV40 induces malignant transformation by the large T-antigen (L-TAG and promotes transformation by binding and inactivating p53 and pRb. L-TAG can bind pRb promoting the activation of the E2F1 transcription factor, thus inducing the expression of genes required for the entry to the S phase and leading to cell transformation. This immunohistochemical study was conducted to assess the prognostic role and relationship of SV40 L-TAG and E2F1 in diffuse large B-cell lymphoma (DLBCL of Egyptian patients. This retrospective study was conducted on 105 tissue specimens including 20 follicular hyperplasia and 85 DLBCL cases. SV40 L-TAG was identified in 3/85 (4% of DLBCL. High Ki-67 labeling index (Ki-67 LI and apoptotic count were associated with high E2F1 expression (p<0.001 for all. No significant association was reached between E2F1 and SV40. E2F1 expression proved to be the most and first independent prognostic factor on overall survival of DLBCL patients (HR = 5.79, 95% CI = 2.3–14.6, and p<0.001. Upregulation of E2F1 has been implicated in oncogenesis, prognosis, and prediction of therapeutic response but is not seemingly to have a relationship with the accused SV40.

  1. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation.

    Science.gov (United States)

    Siipola, Sari M; Kotilainen, Titta; Sipari, Nina; Morales, Luis O; Lindfors, Anders V; Robson, T Matthew; Aphalo, Pedro J

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors. © 2014 John Wiley & Sons Ltd.

  2. Oceanic protection of prebiotic organic compounds from UV radiation.

    Science.gov (United States)

    Cleaves, H J; Miller, S L

    1998-06-23

    It is frequently stated that UV light would cause massive destruction of prebiotic organic compounds because of the absence of an ozone layer. The elevated UV flux of the early sun compounds this problem. This applies to organic compounds of both terrestrial and extraterrestrial origin. Attempts to deal with this problem generally involve atmospheric absorbers. We show here that prebiotic organic polymers as well as several inorganic compounds are sufficient to protect oceanic organic molecules from UV degradation. This aqueous protection is in addition to any atmospheric UV absorbers and should be a ubiquitous planetary phenomenon serving to increase the size of planetary habitable zones.

  3. Immortalization of Porcine 11β-Hydroxysteroid Dehydrogenase Type 1-Transgenic Liver Cells Using SV40 Large T Antigen

    Directory of Open Access Journals (Sweden)

    Hee Young Kang

    2017-12-01

    Full Text Available Cortisol is a steroid hormone essential to the maintenance of homeostasis that is released in response to stress and low blood glucose concentration. Cortisol is converted from cortisone by 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1. It has been reported that too much cortisol or overexpression of HSD11B1 induces obesity and the insulin resistance that accompanies metabolic syndrome in rodent adipose tissue. In our previous study, HSD11B1-transgenic (TG fibroblasts were established, and a porcine model was generated by SCNT using those fibroblasts. Hepatocytes overexpressing HSD11B1 were obtained from livers of this porcine model and cultured in vitro. However, the primary hepatocytes were found to have a short life span or low proliferation rate. To overcome these problems, the SV40 large T antigen was transduced into primary HSD11B1-TG hepatocytes, and those cells were immortalized. Immortalized HSD11B1-TG hepatocytes showed restored morphology, more rapid proliferation rate, and more expression of HSD11B1 than primary hepatocytes. As well, these cells kept the hepatic characteristics such as gluconeogenic response to cortisone and increased expression of hepatic makers. The immortalized HSD11B1-TG hepatocytes may be useful for studying traits and potential therapeutic drugs for treatment of metabolic disorders induced by overexpression of HSD11B1.

  4. Immortalization of Porcine 11β-Hydroxysteroid Dehydrogenase Type 1-Transgenic Liver Cells Using SV40 Large T Antigen.

    Science.gov (United States)

    Kang, Hee Young; Choi, Young-Kwon; Jeong, Yeon Ik; Choi, Kyung-Chul; Hyun, Sang-Hwan; Hwang, Woo-Suk; Jeung, Eui-Bae

    2017-12-05

    Cortisol is a steroid hormone essential to the maintenance of homeostasis that is released in response to stress and low blood glucose concentration. Cortisol is converted from cortisone by 11βhydroxysteroid dehydrogenase type 1 (HSD11B1). It has been reported that too much cortisol or overexpression of HSD11B1 induces obesity and the insulin resistance that accompanies metabolic syndrome in rodent adipose tissue. In our previous study, HSD11B1-transgenic (TG) fibroblasts were established, and a porcine model was generated by SCNT using those fibroblasts. Hepatocytes overexpressing HSD11B1 were obtained from livers of this porcine model and cultured in vitro. However, the primary hepatocytes were found to have a short life span or low proliferation rate. To overcome these problems, the SV40 large T antigen was transduced into primary HSD11B1-TG hepatocytes, and those cells were immortalized. Immortalized HSD11B1-TG hepatocytes showed restored morphology, more rapid proliferation rate, and more expression of HSD11B1 than primary hepatocytes. As well, these cells kept the hepatic characteristics such as gluconeogenic response to cortisone and increased expression of hepatic makers. The immortalized HSD11B1-TG hepatocytes may be useful for studying traits and potential therapeutic drugs for treatment of metabolic disorders induced by overexpression of HSD11B1.

  5. Effects of UV-B radiation on near-surface zooplankton of puget sound.

    Science.gov (United States)

    Damkaer, David M; Dey, Douglas B; Heron, Gayle A; Prentice, Earl F

    1980-01-01

    An increase in incident solar ultraviolet irradiation, resulting from possible deterioration of the stratospheric ozone layer, would have important biological effects. Though the oceans are relatively opaque to UV radiation, compared to visible light, increases in incident UV may affect organisms living within the first few meters of the sea surface.Shrimp larvae, crab larvae, and euphausids were exposed to various low levels of simulated solar UV radiation (UV-B, 290-315 nm) under laboratory conditions. Comparisons between solar and artificial spectra were based on spectroradiometric measurements converted to erythemally effective irradiance. These zooplankton tolerated UV-B irradiance levels up to threshold levels with no significant reduction in survival or developmental rates compared to control organisms. Beyond the threshold levels, activity, development, and survival rapidly declined. The apparent UV thresholds are near present incident UV levels.Observed survival threshold levels for each experimental group were superimposed on seasonal solar incident UV levels at the experimental site. These threshold levels appeared to be exceeded by median ambient UV levels late in the season of surface occurrence of each species. UV increases resulting from ozone depletion may significantly shorten this season. Although the apparent impact would be lessened by the decrease in UV with depth, irreversible detrimental effects would probably occur before reported survival thresholds were exceeded.

  6. Simple and Low-cost Fiber-optic Sensors for Detection of UV Radiation

    Directory of Open Access Journals (Sweden)

    M. B. Živanov

    2012-11-01

    Full Text Available In this paper two simple and low-cost fiberoptic sensors for detection of UV radiation are presented. A U-shaped sensor covered with an UV marker for UV radiation detection and a fiber-optic sensor with one end covered with powder from a mercury lamp are produced and described in details. Both sensors are made of large-core PMMA plastic optical fibers. As UV sources, a solar simulator and four different UV lamps are used. The light spectrum on the fiber output is measured by using an USB spectrometer. Dependence of output light intensity on the distance of end-type sensor with powder from a mercury lamp from UV lamp is investigated as well. On the output of the sensor covered with powder from a mercury lamp are obtained peaks of fluorescent emission at approximately 616 nm and 620 nm wavelengths.

  7. UV radiation, vitamin D, and cancer: how to measure the vitamin D synthetic capacity of UV sources?

    Science.gov (United States)

    Terenetskaya, Irina; Orlova, Tatiana

    2005-09-01

    UV irradiation is widely used in phototherapy. Regardless of the fact that UV overexposure is liable to cause adverse health effect, in appropriate doses UV radiation initiates synthesis of vitamin D in skin that is absolutely essential for human health. As it proved, most people in northern industrial countries have a level of vitamin D in their bodies that is insufficient for optimum health, especially in winter. These low levels of vitamin D are now known to be associated with a wide spectrum of serious disease much of which leads on to premature death. The diseases associated with D deficiency involve more than a dozen types of cancer including colon, breast and prostate, as well as the classic bone diseases: rickets, osteoporosis and osteomalacia. Irradiation with artificial UV sources can prevent the vitamin D deficiency. However, in view of different irradiation spectra of UV lamps, their ability to initiate vitamin D synthesis is different. The reliable method based on an in vitro model of vitamin D synthesis has been developed for direct measurement in situ of the vitamin D synthetic capacity of artificial UV sources during a phototherapeutic procedure

  8. UV radiation and organic matter composition shape bacterial functional diversity in sediments

    Directory of Open Access Journals (Sweden)

    Ellard Roy Hunting

    2013-10-01

    Full Text Available AbstractUV radiation and organic matter (OM composition are known to influence the speciescomposition of bacterioplankton communities. Potential effects of UV radiation onbacterial communities residing in sediments remain completely unexplored to date.However, it has been demonstrated that UV radiation can reach the bottom of shallowwaters and wetlands and alter the OM composition of the sediment, suggesting thatUV radiation may be more important for sediment bacteria than previously anticipated.It is hypothesized here that exposure of shallow OMcontaining sediments to UVradiation induces OMsource dependant shifts in the functional composition ofsediment bacterial communities. This study therefore investigated the combinedinfluence of both UV radiation and OM composition on bacterial functional diversity inlaboratory sediments. Two different organic matter sources, labile and recalcitrantorganic matter (OM, were used and metabolic diversity was measured with BiologGN. Radiation exerted strong negative effects on the metabolic diversity in thetreatments containing recalcitrant OM, more than in treatments containing labile OM.The functional composition of the bacterial community also differed significantlybetween the treatments. Our findings demonstrate that a combined effect of UVradiation and OM composition shapes the functional composition of microbialcommunities developing in sediments, hinting that UV radiation may act as animportant sorting mechanism for bacterial communities and driver for bacterialfunctioning in shallow lakes and wetlands.

  9. Solar UV radiation variations and their stratospheric and climatic effects

    Science.gov (United States)

    Donnelly, R. F.; Heath, D. F.

    1985-01-01

    Nimbus-7 SBUV measurements of the short-term solar UV variations caused by solar rotation and active-region evolution have determined the amplitude and wavelength dependence for the active-region component of solar UV variations. Intermediate-term variations lasting several months are associated with rounds of major new active regions. The UV flux stays near the peak value during the current solar cycle variation for more than two years and peaks about two years later than the sunspot number. Nimbus-7 measurements have observed the concurrent stratospheric ozone variations caused by solar UV variations. There is now no doubt that solar UV variations are an important cause of short- and long-term stratospheric variations, but the strength of the coupling to the troposphere and to climate has not yet been proven.

  10. MicroRNA-22 promotes cell survival upon UV radiation by repressing PTEN

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Guangyun [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States); Jilin Province Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun (China); Shi, Yuling [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States); Wu, Zhao-Hui, E-mail: zwu6@uthsc.edu [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer miR-22 is induced in cells treated with UV radiation. Black-Right-Pointing-Pointer ATM is required for miR-22 induction in response to UV. Black-Right-Pointing-Pointer miR-22 targets 3 Prime -UTR of PTEN to repress its expression in UV-treated cells. Black-Right-Pointing-Pointer Upregulated miR-22 inhibits apoptosis in cells exposed to UV. -- Abstract: DNA damage response upon UV radiation involves a complex network of cellular events required for maintaining the homeostasis and restoring genomic stability of the cells. As a new class of players involved in DNA damage response, the regulation and function of microRNAs in response to UV remain poorly understood. Here we show that UV radiation induces a significant increase of miR-22 expression, which appears to be dependent on the activation of DNA damage responding kinase ATM (ataxia telangiectasia mutated). Increased miR-22 expression may result from enhanced miR-22 maturation in cells exposed to UV. We further found that tumor suppressor gene phosphatase and tensin homolog (PTEN) expression was inversely correlated with miR-22 induction and UV-induced PTEN repression was attenuated by overexpression of a miR-22 inhibitor. Moreover, increased miR-22 expression significantly inhibited the activation of caspase signaling cascade, leading to enhanced cell survival upon UV radiation. Collectively, these results indicate that miR-22 is an important player in the cellular stress response upon UV radiation, which may promote cell survival via the repression of PTEN expression.

  11. Growth of a mat-forming photograph in the presence of UV radiation

    Science.gov (United States)

    Pierson, Beverly K.; Ruff, A. L.

    1989-01-01

    Knowledge of the survival and growth of microorganisms in the presence of ultraviolet radiation is important for understanding the potential for life to exist in environments exposed to high fluxes of UV radiation. The growth of a mat-forming phototrophic prokaryote, Chloroflexus aurantiacus, was examined in the presence of continuous high UV irradiation under otherwise optimal growth conditions. Evidence was sought for an intrinsic ability to grow in the presence of UV radiation in a carefully chosen organism known to be unusually resistant to UV radiation, of ancient lineage among the phototrophs, to resemble ancient microfossils from the Precambrian, and to be a mat-former. It was assumed that even a high intrinsic UV resistance would be inadequate for survival and growth in the presence of very high UV fluxes, and iron (Fe3+) was selected as a common, abundant UV-absorbing substance that might protest microorganisms growing in or under iron-bearing sediments. The effectiveness of Fe(3+) was tested as a UV protective agent at low concentrations in thin layers. It was concluded that intrinsic UV resistance in some organisms may account for growth, not just survival, of these organisms when exposed to high UV fluxes under otherwise optimal growth conditions in an anoxic environment. It was also concluded that Fe(3+) bearing sediments of 1 mm or less in thickness may provide an adequate shield against high UV fluxes permitting the growth of microorganisms just below their surface. As long as growth conditions were met, then the evolution and development of microorganisms would not be hampered by high UV fluxes impinging upon the surface of iron-bearing sediments.

  12. Effects of Litter Exposure to UV Radiation on Subsequent Microbial Decomposition

    Science.gov (United States)

    Lin, Y.; Scarlett, R. D.; King, J. Y.

    2013-12-01

    In arid ecosystems, photodegradation has recently been identified as a key process in ecosystem carbon cycling. Photodegradation directly contributes to organic matter decomposition through photochemical mineralization. However, it remains unclear how photodegradation interacts with biotic decomposition processes. It is commonly thought that photodegradation can facilitate subsequent microbial decomposition, as it can preferentially decompose lignin, a recalcitrant substrate in microbial decomposition. We hypothesized that ultraviolet (UV) radiation exposure would increase the biodegradability of plant litter and that this effect would be greater with longer radiation exposure. In the field at the University of California's Sedgwick Reserve in Santa Ynez, CA, Bromus diandrus litter samples were exposed to two levels of UV radiation using screens: 'UV pass' (transmitting > 81% of UV radiation) and 'UV block' (transmitting carbon and nitrogen content, fiber fractions, water extractable carbon and nitrogen, and biodegradability. We evaluated the biodegradability of litter using a 30-day laboratory incubation experiment. Litter samples were incubated in the dark in sealed glass microcosms with soil inoculum. The CO2 accumulation in each microcosm headspace was measured every 1-2 days to assess microbial respiration rate. In contrast to our hypothesis, litter exposed under UV block conditions had 28% higher cumulative CO2 production than litter from UV pass when the length of exposure was 2.5 months (P = 0.02, n = 4). Litter from the UV block treatment also tended to show higher cumulative CO2 production than litter from UV pass when the exposure lasted for 4 months (P = 0.10, n = 4). For samples with longer exposure times (6 and 12 months), there was no difference in CO2 production between UV pass and UV block treatments. Litter lignin concentration was not affected by UV treatments, regardless of the length of UV exposure. Interestingly, there was a strong correlation

  13. INTERACTIVE EFFECTS OF SOLAR UV RADIATION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLING

    Science.gov (United States)

    This paper assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are o...

  14. Urban forest influences on exposure to UV radiation and potential consequences for human health

    Science.gov (United States)

    Gordon M. Heisler

    2010-01-01

    This chapter explores the literature on ultraviolet (UV) irradiance in urban ecosystems with respect to the likely effects on human health. The focus was the question of whether the health effects of UV radiation should be included in the planning of landscape elements such as trees and shading structures, especially for high use pedestrian areas and school play...

  15. Modeling of urban trees' effects on reducing human exposure to UV radiation in Seoul, Korea

    Science.gov (United States)

    Hang Ryeol Na; Gordon M. Heisler; David J. Nowak; Richard H. Grant

    2014-01-01

    A mathematical model isconstructed for quantifying urban trees’ effects on mitigating the intensity of ultraviolet (UV) radiation on the ground within different landuse types across a city. The model is based upon local field data, meteorological data and equations designed to predict the reduced UV fraction due to trees at the ground level. Trees in Seoul, Korea (2010...

  16. Effects of solar UV-A and UV-B radiation on gene expression and phenolic accumulation in Betula pendula leaves

    Energy Technology Data Exchange (ETDEWEB)

    Morales, L.O.; Tegelberg, R.; Brosche, M.; Aphalo, P.J. [Helsinki Univ., Helsinki (Finland). Dept. of Biosciences, Div. of Plant Biology; Keinanen, M. [Eastern Finland Univ., Joensuu (Finland). Faculty of Biosciences; Lindfors, A. [Edinburgh Univ., Edinburgh (United Kingdom). School of Geosciences, Grant Inst.

    2010-07-15

    Several physiological and ecological processes in plant ecosystems are regulated by solar ultraviolet (UV) radiation. Although UV radiation is an important environmental factor for plant communities, plant responses to solar UV are not fully understood. Therefore, this study examined the effects of different doses of solar UV-A and UV-B radiation on the expression of genes involved in flavonoid biosynthesis and on the accumulation of phenolic compounds in birch leaves after 30 days of exposure outdoors. Plants were exposed to 6 UV treatments using 3 types of plastic film. Epidermal flavonoids measured in vivo decreased when UV-B was excluded. Liquid chromatography-mass spectrometry revealed that the concentrations of 6 flavenoids declined linearly with UV-B exclusion, and transcripts of PAL and HYH measured by quantitative real-time polymerase chain reaction were expressed at lower levels. The results provide a better understanding of plant responses to solar UV radiation at both molecular and metabolite levels. It was concluded that different doses of solar UV-A and UV-B radiation differentially regulate gene expression and the accumulation of flavonoids in birch leaves. 63 refs., 3 tabs., 3 figs.

  17. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

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

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination...... was characterized by simultaneous gas exchange and chlorophyll fluorescence measurements and the PSII performance through the growing season was investigated with fluorescence measurements. Leaf harvest towards the end of the growing season was done to determine the specific leaf area and the content of carbon......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...

  18. The Role of Solar and UV Radiation in Environmental Stress Assessment

    Science.gov (United States)

    2003-11-01

    The purpose of this study was to evaluate the role of solar and UV radiation components in environmental stress assessment and to test the...contribution of the UV radiation variable in a modified environmental stress index (ESI). Meteorological variables, including ambient temperature, wet bulb...calculate the wet bulb globe temperature (WBGT) and the environmental stress index (ESI). Accordingly, analysis of the weight for each parameter from

  19. UV radiation below an Arctic vortex with severe ozone depletion

    Directory of Open Access Journals (Sweden)

    B. M. Knudsen

    2005-01-01

    Full Text Available The erythemally weighted (UV irradiance below the severely depleted Arctic vortices in spring 1996 and 1997 were substantially elevated. On average the UV increased 36 and 33% relative to the 1979-1981 mean assuming clear skies from day 80-100 in 1996 and 1997, respectively. On clear sky days large regions of the Arctic experienced maximum UV increases exceeding 70 and 50% on single days in 1996 and 1997, respectively. A minor fraction of these increases are not anthropogenic and have a dynamical origin as seen by comparison to 1982, when hardly any ozone depletion is expected.

  20. Effect of UV radiation and its implications on carotenoid pathway in Bixa orellana L.

    Science.gov (United States)

    Sankari, M; Hridya, H; Sneha, P; George Priya Doss, C; Ramamoorthy, Siva

    2017-11-01

    The current study was undertaken to analyse the effect of short-term UV-B and UV-C radiations in provoking carotenoid biosynthesis in Bixa orellana. Seeds of B. orellana were germinated and exposed to the short term UV pre-treatment under controlled environmental condition for 5days. The UV treated young seedlings response in pigment contents; antioxidant enzyme activity and mRNA gene expression level were analysed. The pigment content such as chlorophyll was increased in both UV-B and UV-C treated seedlings, but the total carotenoid level was decreased when compared to the control seedlings this can be attributed to the plant adaptability to survive in a stressed condition. The β-carotene level was increased in UV-B, and UV-C treated young seedlings. No significant changes have occurred in the secondary pigment such as bixin and ABA. The activity of the antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase was significantly increased in UV-B treated seedlings when compared to the UV-C treated seedlings and control. The mRNA expression of the genes involved in bixin biosynthesis pathways such as DXS, PSY, PDS, LCY-β, LCY-ε, CMT, LCD, ADH and CCD genes showed different expression pattern in UV-B and UV-C treated young seedlings. Further we analysed the gene co-expression network to identify the genes which are mainly involved in carotenoid/bixin biosynthesis pathway. Form our findings the CCD, LCY, PDS, ZDS and PSY showed a close interaction. The result of our study shows that the short term UV-B and UV-C radiations induce pigment content, antioxidant enzyme activity and different gene expression pattern allowing the plant to survive in the oxidative stress condition. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Sensitivity to UV radiation in early life stages of the Mediterranean sea urchin Sphaerechinus granularis (Lamarck)

    Energy Technology Data Exchange (ETDEWEB)

    Nahon, Sarah [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Castro Porras, Viviana A. [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Pruski, Audrey M. [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Charles, Francois [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France)], E-mail: charles@obs-banyuls.fr

    2009-03-01

    The sea urchin Sphaerechinus granularis was used to investigate the impact of relevant levels of UV-B radiation on the early life stages of a common Mediterranean free spawning benthic species. Sperm, eggs and embryos were exposed to a range of UV radiation doses. The resulting endpoints were evaluated in terms of fertilisation success, development and survival rates. Above a weighted UV radiation dose of 0.0029 kJ m{sup -2}, fertilisation capability of irradiated sperm decreased rapidly. The exposure of the eggs to 0.0175 kJ m{sup -2} and more led to delayed and inhibited development with ensuing embryonic morphological abnormalities. One-day old larvae remained strongly sensitive to UV radiation as shown by the 50% decrease of the larval survival rate for a dose of 0.025 kJ m{sup -2} UVR. The elevated sensitivity of embryos to experimental UVR went along with a lack of significant amount of sunscreen compounds (e.g., mycosporine-like amino acids) in the eggs. The present results demonstrated that gamete viability and embryonic development may be significantly impaired by solar UV radiation in S. granularis, compromising in this way the reproduction of the species. Unless adaptive behavioural reproductive strategies exist, the influence of ambient UV radiation appears as a selective force for population dynamics of broadcast spawners in the shallow benthic Mediterranean environment.

  2. Near-UV radiation acts as a beneficial factor for physiological responses in cucumber plants.

    Science.gov (United States)

    Mitani-Sano, Makiko; Tezuka, Takafumi

    2013-11-05

    Effects of near-UV radiation on the growth and physiological activity of cucumber plants were investigated morphologically, physiologically and biochemically using 3-week-old seedlings grown under polyvinyl chloride films featuring transmission either above 290 nm or above 400 nm in growth chambers. The hypocotyl length and leaf area of cucumber seedlings were reduced but the thickness of leaves was enhanced by near-UV radiation, due to increased upper/lower epidermis thickness, palisade parenchyma thickness and volume of palisade parenchyma cells. Photosynthetic and respiratory activities were also promoted by near-UV radiation, associated with general enhancement of physiological/biochemical responses. Particularly, metabolic activities in the photosynthetic system of chloroplasts and the respiratory system of mitochondria were analyzed under the conditions of visible light with and without near-UV radiation. For example, the activities of NAD(P)-dependent enzymes such as glyceraldehyde-3-phosphate dehydrogenase (G3PDH) in chloroplasts and isocitrate dehydrogenase (ICDH) in mitochondria were elevated, along with levels of pyridine nucleotides (nicotinamide coenzymes) [NAD(H) and NADP(H)] and activity of NAD kinase (NADP forming enzyme). Taken together, these data suggest that promotion of cucumber plant growth by near-UV radiation involves activation of carbon and nitrogen metabolism in plants. The findings of this research showed that near-UV radiation reaching the Earth's surface is a beneficial factor for plant growth. Copyright © 2013. Published by Elsevier B.V.

  3. Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Petin, Vladislav G.; Morozov, Ivan I. [Biophysical Laboratory, Medical Radiological Research Center, 249036 Obninsk, Kaluga Region (Russian Federation); Kim, Jin Kyu, E-mail: jkkim@kaeri.re.k [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup 580-185 (Korea, Republic of); Semkina, Maria A. [Biophysical Laboratory, Medical Radiological Research Center, 249036 Obninsk, Kaluga Region (Russian Federation)

    2011-01-15

    A simple mathematical model for biological estimation of UV light dose concomitant to ionizing radiation was suggested. This approach was applied to determine the dependency of equivalent UV light dose accompanied by 100 Gy of ionizing radiation on energy of sparsely ionizing radiation and on volume of the exposed cell suspension. It was revealed that the relative excitation contribution to the total lethal effect and the value of UV dose was greatly increased with an increase in energy of ionizing radiation and volume of irradiated suspensions. It is concluded that these observations are in agreement with the supposition that Cerenkov emission is responsible for the production of UV light damage and the phenomenon of photoreactivation observed after ionizing exposure of bacterial and yeast cells hypersensitive to UV light. A possible synergistic interaction of the damages produced by ionizations and excitations as well as a probable participation of UV component of ionizing radiation in the mechanism of hormesis and adaptive response observed after ionizing radiation exposure is discussed.

  4. Di-thiourea cadmium chloride crystals synthesis under UV radiation influence

    Science.gov (United States)

    Trujillo, L. E.; Chávez-Urbiola, E. A.; Legorreta, F.; Chávez-Urbiola, I. R.; Willars-Rodriguez, F. J.; Ramírez-Bon, R.; Ramírez-Cardona, M.

    2017-11-01

    In this work, the effect of ultraviolet radiation (λ = 367 nm) on the synthesis of di-thiourea cadmium chloride crystals by the chemical bath technique was studied. The results were analyzed and characterized by different techniques: X-ray diffraction (XRD), Raman scattering, scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA). It was found that the effect of ultraviolet radiation (UV) on the crystals causes a preferential growth in the (0 0 1) and (0 2 0) planes due to an increase in the formation of the Cdsbnd Cl and CS bonds caused by UV radiation. A morphological change was observed in the crystals assisted by UV radiation, and finally, it was found that the decomposition of the crystals starts from 497 K thus transforming the di-thiourea cadmium chloride into cadmium sulfide. Also, the growth rate is increased by incorporating ultraviolet radiation into the reaction.

  5. Different atmospheric parameters influence on spectral UV radiation (measurements and modelling)

    Energy Technology Data Exchange (ETDEWEB)

    Chubarova, N.Y. [Moscow State Univ. (Russian Federation). Meteorological Observatory; Krotkov, N.A. [Maryland Univ., MD (United States). JCESS/Meteorology Dept.; Geogdzhaev, I.V.; Bushnev, S.V.; Kondranin, T.V. [SUMGF/MIPT, Dolgoprudny (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Dolgoprudny (Russian Federation)

    1995-12-31

    The ultraviolet (UV) radiation plays a vital role in the biophysical processes despite its small portion in the total solar flux. UV radiation is subject to large variations at the Earth surface depending greatly on solar elevation, ozone and cloud amount, aerosols and surface albedo. The analysis of atmospheric parameters influence is based on the spectral archive data of three spectral instruments: NSF spectroradiometer (Barrow network) (NSF Polar Programs UV Spectroradiometer Network 1991-1992,1992), spectrophotometer (SUVS-M) of Central Aerological Observatory CAO, spectroradiometer of Meteorological Observatory of the Moscow State University (MO MSU) and model simulations based on delta-Eddington approximation

  6. Removing UV-A and UV-C radiation from UV-B fluorescent lamp emissions. Differences in the inhibition of photosynthesis in the marine alga Dunaliella tertiolecta using chromate versus cellulose acetate-polyester filters.

    Science.gov (United States)

    White, Andrea L; Jahnke, Leland S

    2004-01-01

    Ultraviolet-B (UV-B; 280-320 nm)-emitting lamps unavoidably emit ultraviolet-A (UV-A; 320-400 nm) and ultraviolet-C (UV-C; <280 nm) radiation. Short-wavelength-blocking filters are generally used to limit the wave bands of UV under investigation. The widespread use of such filters means that all exposures to UV-B radiation will have a significant UV-A component. Therefore, the physiological effects unique to UV-B exposure are difficult to clearly isolate. This study presents a method to remove the UV-A and UV-C "contamination" using a liquid potassium chromate (K(2)CrO(4)) filter, thus allowing more direct assessment of the effects of UV-B exposure. Cultures of the green marine alga Dunaliella tertiolecta were grown in the absence of UV radiation. Sunlamps supplied the UV radiation for a 24 h exposure (solar radiation was not used in this study). The UV radiation was filtered either by the standard method (i.e. cellulose acetate (CA) with polyester = Mylar controls) or by a liquid filter of potassium chromate. Photosynthetic responses were compared. Major decreases in the ratio of variable to maximal fluorescence in dark-adapted cells and photosynthetic capacity were observed in CA-filtered cultures, whereas no change was observed in cells exposed to the same UV-B flux with the UV-A removed by K(2)CrO(4). The use of a CA filter with a Mylar control does not link results unequivocally to UV-B radiation. Such results should be interpreted with caution.

  7. UV radiation impacts body weight, oxygen consumption, and shelter selection in the intertidal vertebrate Girella laevifrons.

    Science.gov (United States)

    Pulgar, José; Waldisperg, Melany; Galbán-Malagón, Cristóbal; Maturana, Diego; Pulgar, Victor M; Aldana, Marcela

    2017-02-01

    The amount of ultraviolet (UV) radiation reaching the earth's surface has increased due to ozone layer depletion, and this fact represents an opportunity to evaluate the physiological and behavioral responses of animals to this global-scale stressor. The transitory fish Girella laevifrons inhabits pools in the upper intertidal zone, which is characterized by exposure to a wide range of stressors, including UV radiation. We documented the field magnitude and the impact of UV radiation on oxygen consumption, body mass variations, and shelter (rocky and algae) selection by G. laevifrons. UV-exposed animals showed increased oxygen consumption, slower body weight increase, and active rocky shelter selection. Control fish showed increased body weight and no evident shelter selection. The results indicated that UV exposure affects fish energetic balance and habitat selection to favor greater protection against radiation. Increased UV exposure in transitory intertidal animals at levels observed in upper intertidal pools may alter the residency time of fish before leaving for the subtidal zone. Therefore, UV-induced energetic changes may determine animal performance and ontogenetic physiological itineraries, whereas shelter quality might determine habitat use. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Response of hoary alyssum (Berteroa incana L. to UV-B radiation

    Directory of Open Access Journals (Sweden)

    Agnieszka Stokłosa

    2012-12-01

    Full Text Available This greenhouse experiment evaluated the response of hoary alyssum plants, up to the rosette phase, to different levels of UV-B radiation. The experiment was carried out in the chambers, equipped with UV-B lamps, emitting biologically effective UV-B radiation of 0 (control, 4, 6 or 8 kJ. As a result, specific traits of the plants such as: leaf number, lamina length, leaf area, specific leaf weight, relative chlorophyll content and shoot biomass were unaffected by any of the UV-B treatments. Significant reductions in the share of large leaves, leaf stalk length and root biomass were noted for plants growing under 8 kJ UV-BBE.

  9. [Responses of enzymes in terrestrial plants to enhanced UV-B radiation].

    Science.gov (United States)

    Yao, Xiaoqin; Liu, Qing

    2006-05-01

    With the destruction of ozone layer, ultraviolet-B (UV-B, 280 to approximately 320nm) radiation has being enhanced at the earth's surface. The energy of UV-B irradiation is far higher than that of visible light, which could be absorbed by biomacromolecules such as protein and nuclei acid. Enzyme is a sort of protein catalyzing the biochemical processes, and its content and activity in plant have strong responses to enhanced UV-B radiation. This paper summarized the research advances in the effects of enhanced UV-B radiation on the key enzymes, mainly including antioxidant enzymes, ribulose-1, 5-diphosphoscarboxylase, nitrate reductase and glutamine synthetase in terrestrial plants. Some suggestions for future research in this field were put forward.

  10. Decreased frost hardiness of Vaccinium vitis-idaea in reponse to UV-A radiation.

    Science.gov (United States)

    Taulavuori, Kari; Keränen, Johanna; Suokanerva, Hanne; Lakkala, Kaisa; Huttunen, Satu; Laine, Kari; Taulavuori, Erja

    2012-08-01

    The aim of this study was to investigate plant frost hardiness responses to ultraviolet (UV) radiation, since the few results reported are largely contradictory. It was hypothesized that functional adaptation of life forms could explain these contradictions. Dwarf shrubs and tree seedlings, representing both evergreen and deciduous forms, were tested (Vaccinium vitis-idaea, Vaccinium myrtillus, Pinus sylvestris, Betula pubescens and its red form f. rubra). The research was performed in Sodankylä, Northern Finland (67°N), with enhanced UV-B- and UV-A-radiation treatments between 2002 and 2009. Plant frost hardiness was determined using the freeze-induced electrolyte leakage method in early autumn, during the onset of the frost hardening process. Additional physiological variables (malondialdehyde, glutathione, total phenols, C and N contents) were analyzed in V. vitis-idaea to explain the possible responses. These variables did not respond significantly to UV-radiation treatments, but explained the frost hardiness well (r² = 0.678). The main finding was that frost hardiness decreased in the evergreen shrub V. vitis-idaea, particularly with enhanced UV-A radiation. No significant responses were observed with the other plants. Therefore, this study does not support the idea that enhanced UV radiation could increase plant frost hardiness. Copyright © Physiologia Plantarum 2011.

  11. Enhancement of UV Radiation by Cloud Effect in NE of Brazil

    Directory of Open Access Journals (Sweden)

    Chigueru Tiba

    2017-01-01

    Full Text Available This paper reports a detailed analysis of ground-based measurements of cloud-enhanced global solar and UV radiation in NE Brazil in the city of Recife. It was found that (a the phenomenon of UV enhancement, above clear sky model, is not uncommon and that it occurs on at least eight months; (b the cumulative duration can reach 13 minutes; (c there is a clear seasonal effect, and the probability of occurrence on a monthly basis shows two peaks, one in March and another in October; and (d the most extreme UV radiation was 70.4 W/m2, approximately 6 W/m2 higher than the clear sky UV radiation. The extreme values should be taken into account in the study of effects related to the UV index and biological effects. Two statistical models also were elaborated, to estimate the UV solar radiation, in which the first is for all sky conditions and the second exclusively for situations where the global solar radiation is equal to or higher than 1367 W/m2, resulting from the enhancement effect caused by a particular configuration of the clouds. The statistical indicatives for both models presented, respectively, MBE% of 3.09 and 0.48% and RMSE% of 15.80 and 3.90%.

  12. STX140, but not paclitaxel, inhibits mammary tumour initiation and progression in C3(1/SV40 T/t-antigen transgenic mice.

    Directory of Open Access Journals (Sweden)

    Florence Meyer-Losic

    Full Text Available Despite paclitxael's clinical success, treating hormone-refractory breast cancer remains challenging. Paclitaxel has a poor pharmacological profile, characterized by a low therapeutic index (TIX caused by severe dose limiting toxicities, such as neutropenia and peripheral neuropathy. Consequently, new drugs are urgently required. STX140, a compound previously shown to have excellent efficacy against many tumors, is here compared to paclitaxel in three translational in vivo breast cancer models, a rat model of peripheral neuropathy, and through pharmacological testing. Three different in vivo mouse models of breast cancer were used; the metastatic 4T1 orthotopic model, the C3(1/SV40 T-Ag model, and the MDA-MB-231 xenograft model. To determine TIX and pharmacological profile of STX140, a comprehensive dosing regime was performed in mice bearing MDA-MD-231 xenografts. Finally, peripheral neuropathy was examined using a rat plantar thermal hyperalgesia model. In the 4T1 metastatic model, STX140 and paclitaxel significantly inhibited primary tumor growth and lung metastases. All C3(1/SV40 T-Ag mice in the control and paclitaxel treated groups developed palpable mammary cancer. STX140 blocked 47% of tumors developing and significantly inhibited growth of tumors that did develop. STX140 treatment caused a significant (P<0.001 survival advantage for animals in early and late intervention groups. Conversely, in C3(1/SV40 T-Ag mice, paclitaxel failed to inhibit tumor growth and did not increase survival time. Furthermore, paclitaxel, but not STX140, induced significant peripheral neuropathy and neutropenia. These results show that STX140 has a greater anti-cancer efficacy, TIX, and reduced neurotoxicity compared to paclitaxel in C3(1/SV40 T-Ag mice and therefore may be of significant benefit to patients with breast cancer.

  13. arXiv Radiative symmetry breaking from interacting UV fixed points

    CERN Document Server

    Abel, Steven

    2017-09-28

    It is shown that the addition of positive mass-squared terms to asymptotically safe gauge-Yukawa theories with perturbative UV fixed points leads to calculable radiative symmetry breaking in the IR. This phenomenon, and the multiplicative running of the operators that lies behind it, is akin to the radiative symmetry breaking that occurs in the supersymmetric standard model.

  14. Transcriptional mapping of rabies virus in vivo. [UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Flamand, A. (Univ. Paris, Orsay, France); Delagneau, J.F.

    1978-11-01

    Synthesis of the proteins of rabies virus was studied in hamster cell infected with uv-irradiated virus. The uv target size of genes L, N, M/sub 1/, and M/sub 2/ was measured during primary transcription. Except for N, the target size of the remaining genes was considerably larger than that of their physical sizes. The data fit the hypothesis that four genes occupy a single transcriptional unit and that transcription of rabies virus proceeds in the order N, M/sub 1/, M/sub 2/, and L.

  15. Arginine-rich cross-linking peptides with different SV40 nuclear localization signal content as vectors for intranuclear DNA delivery.

    Science.gov (United States)

    Bogacheva, Mariia; Egorova, Anna; Slita, Anna; Maretina, Marianna; Baranov, Vladislav; Kiselev, Anton

    2017-11-01

    The major barriers for intracellular DNA transportation by cationic polymers are their toxicity, poor endosomal escape and inefficient nuclear uptake. Therefore, we designed novel modular peptide-based carriers modified with SV40 nuclear localization signal (NLS). Core peptide consists of arginine, histidine and cysteine residues for DNA condensation, endosomal escape promotion and interpeptide cross-linking, respectively. We investigated three polyplexes with different NLS content (10 mol%, 50 mol% and 90 mol% of SV40 NLS) as vectors for intranuclear DNA delivery. All carriers tested were able to condense DNA, to protect it from DNAase I and were not toxic to the cells. We observed that cell cycle arrest by hydroxyurea did not affect transfection efficacy of NLS-modified carriers which we confirmed using quantitative confocal microscopy analysis. Overall, peptide carrier modified with 90 mol% of SV40 NLS provided efficient transfection and nuclear uptake in non-dividing cells. Thus, incorporation of NLS into arginine-rich cross-linking peptides is an adequate approach to the development of efficient intranuclear gene delivery vehicles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Environmental cues to UV radiation and personal sun protection in outdoor winter recreation.

    Science.gov (United States)

    Andersen, Peter A; Buller, David B; Walkosz, Barbara J; Scott, Michael D; Maloy, Julie A; Cutter, Gary R; Dignan, Mark D

    2010-11-01

    To predict the prevalence of UV radiation (hereinafter, UV) at North American ski resorts using temporal, seasonal, altitudinal, and meteorological factors and associate UV with a set of adult sun protection behaviors. Ultraviolet radiation observations and cross-sectional survey of adults on sun protection were collected. Data were collected at 32 high-altitude ski areas located in western North America from 2001 through 2003. The sample consisted of 3937 adult skiers or snowboarders. Measurements of direct, reflected, and diffuse UV were performed at 487 measurement points using handheld meters and combined with self-reported and observed sun protection assessed for adults interviewed on chairlifts. The strongest predictors of UV were temporal proximity to noon, deviation from winter solstice, and clear skies. By contrast, altitude and latitude had more modest associations with UV and temperature had a small positive relationship with UV. Guest sun safety was inconsistently associated with UV: UV was positively related to adults wearing more sunscreen, reapplying it after 2 hours, and wearing protective eyewear, but fewer adults exhibited many of the other sun protection behaviors, such as wearing hats and protective clothing or using lip balm, on days when UV was elevated. Guests took more sun safety precautions on clear-sky days but took steps to maintain body warmth on inclement days. In future sun safety promotions, adults should be encouraged to wear sunscreen on cloudy days because UV is still high and conditions can change rapidly. They need reminders to rely more on season and time of day when judging UV and the need for sun safety.

  17. Effects of Aerosol Optical Depth on diffuse UV and visible radiation

    Science.gov (United States)

    Kim, Y.; Kim, J.; Cho, H.; Kim, Y.

    2007-12-01

    Ultraviolet radiation (UV, 300-367nm) was measured with a UV-multifilter rotating shadowband radiometer (UV- MFRSR) at Yonsei University, Seoul (37.57°N, 126.97°) for 7 months from January to July 2006 and visible irradiance (400-700 nm) also measured with a MFRSR for 12 months of 2006 at the same station. Spectral UV_AOD and vis_AOD were retrieved using the Langley method and Beer-Bouguer-Lambert's law, and compared with AOD obtained from Skyradiometer to validate their values. The diffuse and direct irradiance were analyzed to investigate the dependence on total optical depth (TOD) and aerosol optical depth (AOD). The direct-horizontal solar irradiance decreases exponentially as the optical depth increases according to the Beer- Bouguer-Lambert's Law. As the TOD and AOD increase, the diffuse-horizontal UV radiation gradually increases and shows a maximum value at some critical optical depth for a given SZA. Similar analysis was performed on the relation between the diffuse irradiance and AOD. RAF(radiation amplification factor) was used to correct the ozone effects on UV. These results provide empirical equations for the amount of diffuse irradiance in UV and visible wavelengths.

  18. UV-C Radiation as a Factor Reducing Microbiological Contamination of Fish Meal

    Directory of Open Access Journals (Sweden)

    Krzysztof Skowron

    2014-01-01

    Full Text Available Fish meals, added to feeds as a source of protein, may contain pathogenic bacteria. Therefore, effective methods for their sanitizing, such as UV-C radiation, are needed to minimize the epidemiological risk. The objective of this study was to evaluate the effect of UV-C radiation on the sanitary state of fish meals. The research materials included salmon and cod meals. Samples of the fish meals were inoculated with suspensions of Salmonella, E. coli, enterococci, and C. sporogenes spores and exposed to the following surface UV-C fluencies: 0–400 J·m−2 for bacteria and 0–5000 J·m−2 for spores. For the vegetative forms, the highest theoretical lethal UV-C dose, ranging from 670.99 to 688.36 J·m−2 depending on the meal type, was determined for Salmonella. The lowest UV-C fluency of 363.34–363.95 J·m−2 was needed for the inactivation of Enterococcus spp. Spores were considerably more resistant, and the UV-C doses necessary for inactivation were 159571.1 J·m−2 in salmon meal and 66836.9 J·m−2 in cod meal. The application of UV-C radiation for the sanitization of fish meals proved to be a relatively effective method for vegetative forms of bacteria but was practically ineffective for spores.

  19. UV-C Radiation as a Factor Reducing Microbiological Contamination of Fish Meal

    Science.gov (United States)

    Dobrzański, Zbigniew; Skowron, Karolina Jadwiga

    2014-01-01

    Fish meals, added to feeds as a source of protein, may contain pathogenic bacteria. Therefore, effective methods for their sanitizing, such as UV-C radiation, are needed to minimize the epidemiological risk. The objective of this study was to evaluate the effect of UV-C radiation on the sanitary state of fish meals. The research materials included salmon and cod meals. Samples of the fish meals were inoculated with suspensions of Salmonella, E. coli, enterococci, and C. sporogenes spores and exposed to the following surface UV-C fluencies: 0–400 J·m−2 for bacteria and 0–5000 J·m−2 for spores. For the vegetative forms, the highest theoretical lethal UV-C dose, ranging from 670.99 to 688.36 J·m−2 depending on the meal type, was determined for Salmonella. The lowest UV-C fluency of 363.34–363.95 J·m−2 was needed for the inactivation of Enterococcus spp. Spores were considerably more resistant, and the UV-C doses necessary for inactivation were 159571.1 J·m−2 in salmon meal and 66836.9 J·m−2 in cod meal. The application of UV-C radiation for the sanitization of fish meals proved to be a relatively effective method for vegetative forms of bacteria but was practically ineffective for spores. PMID:24578670

  20. Influence of low ozone episodes on erythemal UV-B radiation in Austria

    Science.gov (United States)

    Schwarz, Matthias; Baumgartner, Dietmar J.; Pietsch, Helga; Blumthaler, Mario; Weihs, Philipp; Rieder, Harald E.

    2017-06-01

    This study investigates the influence of low ozone episodes on UV-B radiation in Austria during the period 1999 to 2015. To this aim observations of total column ozone (TCO) in the Greater Alpine Region (Arosa, Switzerland; Hohenpeissenberg, Germany; Hradec Kralove, Czech Republic; Sonnblick, Austria), and erythemal UV-B radiation, available from 12 sites of the Austrian UV-B monitoring network, are analyzed. As previous definitions for low ozone episodes are not particularly suited to investigate effects on UV radiation, a novel threshold approach—considering anomalies—is developed to provide a joint framework for the analysis of extremes. TCO and UV extremes are negatively correlated, although modulating effects of sunshine duration impact the robustness of the statistical relationship. Therefore, information on relative sunshine duration (SDrel), available at (or nearby) UV-B monitoring sites, is included as explanatory variable in the analysis. The joint analysis of anomalies of both UV index (UVI) and total ozone (∆UVI, ∆TCO) and SDrel across sites shows that more than 65% of observations with strongly negative ozone anomalies (∆TCO 1), we find (across all sites) that about 90% correspond to negative ∆TCO. The remaining 10% of days occurred during fair weather conditions (SDrel ≥ 80%) explaining the appearance of ∆UVI > 1 despite positive TCO anomalies. Further, we introduce an anomaly amplification factor (AAF), which quantifies the expected change of the ∆UVI for a given change in ∆TCO.

  1. Effects of Stratospheric Ozone Depletion, Solar UV Radiation, and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    Science.gov (United States)

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment...

  2. Exposure of Finnish population to solar UV radiation and consequent carcinogenic effects

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Jansen, C. [Turku Univ. Hospital, Turku (Finland); Jokela, K. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1996-12-31

    Depletion of stratospheric ozone increases irradiance of terrestrial ultraviolet (UV) radiation at short wavelengths, which may be harmful to the human health. To understand quantitatively the risks caused by increasing UV radiation to the Finnish population, the actual UV exposure of the population has to be assessed. It was shown that the snow reflection increases the UV exposure to the face and eyes particularly in the northern Finland. In 1993 exceptionally low ozone levels persisted up to the end of May, which resulted in a theoretical increase in the annual UV dose ranging from 8 % to 13 % in Finland. The maximal increase in the measured erythemally effective dose rate was 34 % on 23 April, when compared with the theoretical normal value. During this study exposure models have been developed. The models have been combined them with Green`s radiation transfer model to estimate annual facial UV doses received by different groups of Finnish population. Also, an updated estimate for increase in skin cancer incidence due to the ozone depletion is presented. It is estimated that the maximal increase in UV doses caused by the depletion of the stratospheric ozone will be 12 % in the first years of the next century in Finland. This may result in increase in skin carcinomas by 20-30 % if the people do not improve their protection against solar UV radiation. At the moment the annual facial UV dose of the Finnish indoor worker varies from 3 % to 6 % of the annual ambient dose. In the worst case an outdoor worker may receive even 16% of the annual ambient dose. However, the doses received by indoor workers during vacation to an untanned skin may be more harmful due to the increased risk of malignant melanoma.

  3. Biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum exposed to enhanced UV-B radiation.

    Science.gov (United States)

    Yao, Xiaoqin; Chu, Jian-Zhou; Ma, Chun-Hui; Si, Chao; Li, Ji-Gang; Shi, Xiao-Fei; Liu, Chao-Nan

    2015-08-01

    The article studied UV-B effects on biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum. The experiment about UV-B effects on biochemical traits in flowers included six levels of UV-B treatments (0 (UV0), 50 (UV50), 200 (UV200), 400 (UV400), 600 (UV600) and 800 (UV800) μWcm(-2)). UV400, UV600 and UV800 treatments significantly increased the contents of hydrogen peroxide, malondialdehyde and UV-B absorbing compounds, and the activity of phenylalanine ammonia lyase enzyme over the control. The contents of chlorogenic acid and flavone in flowers were significantly increased by UV-B treatments (except for UV50 and UV800). Two-dimensional gel electrophoresis was utilized to analyze proteomic changes in flowers with or without UV-B radiation. Results indicated that 43 protein spots (>1.5-fold difference in volume) were detected, including 19 spots with a decreasing trend and 24 spots with an increasing trend, and 19 differentially expressed protein spots were successfully indentified by MALDI-TOF MS. The indentified proteins were classified based on functions, the most of which were involved in photosynthesis, respiration, protein biosynthesis and degradation and defence. An overall assessment using biochemical and differential proteomic data revealed that UV-B radiation could affect biochemical reaction and promote secondary metabolism processes in postharvest flowers. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. An assessment of ozone levels, UV radiation and their occupational health hazard estimation during photocopying operation

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Bhupendra Pratap, E-mail: bpsingh0783@gmail.com; Kumar, Amit; Singh, Deepak; Punia, Monika; Kumar, Krishan; Jain, Vinod Kumar

    2014-06-30

    Highlights: • First quantitative report of ozone level and UV radiation emission from photocopier. • Ozone production is directly proportional with intensity of photocopy operation. • Ozone level from ground floor is significantly higher than basement photocopier. • Ozone production and UV radiation studied has less correlation during photocopy. • Health hazard issue has been evaluated for effect of UV radiation in terms of SED. - Abstract: This study investigates the levels of ozone concentration along with an ultraviolet (UV) and visible spectral radiation at eight photocopy centers in an academic institute, Delhi. Sampling was done in two types of locations, i.e., basement photocopy centers (BPC) and ground floor photocopy centers (GPC) for 8 h. Measurements of levels of ozone, UV and visible radiation were done by ozone analyzer, UV radiometer and Field spectra instrument, respectively. Results show that the hourly mean concentration of ozone was observed to be in the range of 1.8–10.0 ppb and 5.3–45.8 ppb for BPC and GPC, respectively. In terms UV radiations, energy lies between 5.0 × 10{sup −3} and 7.0 × 10{sup −3} mW/cm{sup 2} for ultraviolet A (UVA), 1.0 × 10{sup −3} and 2.0 × 10{sup −3} mW/cm{sup 2} for ultraviolet B (UVB) and 6.0 × 10{sup −3} and 8.0 × 10{sup −3} mW/cm{sup 2} for ultraviolet C (UVC). Correlation between the UV radiations and ozone production observed was statistically insignificant. To know the health hazard occurred to the workers, the standard erythema dose (SED) value was calculated for emitting UV radiation. The SED was estimated to be in the range of 0.02–0.04 and 0.02–0.32 for direct and indirect methods which is less than the guideline prescribed by Commission Internationale del’ Eclairage (CIE). In nutshell, person involved in photocopy operation for their livelihood must be trained and should have knowledge for the long term gradual build up health problems due to ozone and UV production from

  5. Extensive reduction of surface UV radiation since 1750 in world's populated regions

    Directory of Open Access Journals (Sweden)

    M. M. Kvalevåg

    2009-10-01

    Full Text Available Human activity influences a wide range of components that affect the surface UV radiation levels, among them ozone at high latitudes. We calculate the effect of human-induced changes in the surface erythemally weighted ultra-violet radiation (UV-E since 1750. We compare results from a radiative transfer model to surface UV-E radiation for year 2000 derived by satellite observations (from Total Ozone Mapping Spectroradiometer and to ground based measurements at 14 sites. The model correlates well with the observations; the correlation coefficients are 0.97 and 0.98 for satellite and ground based measurements, respectively. In addition to the effect of changes in ozone, we also investigate the effect of changes in SO2, NO2, the direct and indirect effects of aerosols, albedo changes and aviation-induced contrails and cirrus. The results show an increase of surface UV-E in polar regions, most strongly in the Southern Hemisphere. Furthermore, our study also shows an extensive surface UV-E reduction over most land areas; a reduction up to 20% since 1750 is found in some industrialized regions. This reduction in UV-E over the industrial period is particularly large in highly populated regions.

  6. Variability in tolerance to UV-B radiation among Beauveria spp. isolates.

    Science.gov (United States)

    Fernandes, Everton K K; Rangel, Drauzio E N; Moraes, Aurea M L; Bittencourt, Vânia R E P; Roberts, Donald W

    2007-11-01

    Solar radiation, particularly the UV-B component, negatively affects survival of entomopathogenic fungi in the field. In an effort to identify Beauveria spp. isolates with promise for use in biological control settings with high insolation, we examined 53 Beauveria bassiana isolates, 7 isolates of 4 other Beauveria spp. and Engyodontium albus (=Beauveria alba). The origins of these fungi varied widely as to host/substrate and country, but approximately 30% of these isolates were B. bassiana from ticks in Brazil. A preliminary trial with three B. bassiana isolates (Bb 19, CG 310 and CG 481) at several UV-B dosages indicated that 2h of weighted UV-B irradiance at 978mWm(-2) (providing a total dose of 7.04kJm(-2)) allowed separation of isolates into low, medium or high UV-B tolerance. This dose, therefore, was selected as a single dose to compare UV-B tolerances of all 60 Beauveria spp. isolates. There was high variability in tolerance to UV-B radiation among the B. bassiana isolates, ranging from virtually zero tolerance (e.g., Bb 03) to almost 80% tolerance (e.g., CG 228). In addition, surviving B. bassiana conidia demonstrated delayed germination; and this is likely to reduce virulence. Conidia of the other species were markedly more sensitive to UV-B, with E. albus (UFPE 3138) being the least UV-B tolerant. Among B. bassiana isolates originating from 0 degrees to 22 degrees latitudes, those from lower latitudes demonstrated statistically significant greater UV-B tolerances than those isolates from higher latitudes. Isolates from above 22 degrees , however, were unaffected by latitude of origin. A similar analysis based on host type did not indicate a correlation between original host and UV-B tolerance. The identification in this study of several B. bassiana isolates with relatively high UV-B tolerance will guide the selection of isolates for future arthropod microbial control experiments.

  7. UV-B radiation impacts shoot tissue pigment composition in Allium fistulosum L. cultigens.

    Science.gov (United States)

    Abney, Kristin R; Kopsell, Dean A; Sams, Carl E; Zivanovic, Svetlana; Kopsell, David E

    2013-01-01

    Plants from the Allium genus are valued worldwide for culinary flavor and medicinal attributes. In this study, 16 cultigens of bunching onion (Allium fistulosum L.) were grown in a glasshouse under filtered UV radiation (control) or supplemental UV-B radiation [7.0  μ mol·m(-2) · s(-2) (2.68 W · m(-2))] to determine impacts on growth, physiological parameters, and nutritional quality. Supplemental UV-B radiation influenced shoot tissue carotenoid concentrations in some, but not all, of the bunching onions. Xanthophyll carotenoid pigments lutein and β -carotene and chlorophylls a and b in shoot tissues differed between UV-B radiation treatments and among cultigens. Cultigen "Pesoenyj" responded to supplemental UV-B radiation with increases in the ratio of zeaxanthin + antheraxanthin to zeaxanthin + antheraxanthin + violaxanthin, which may indicate a flux in the xanthophyll carotenoids towards deepoxydation, commonly found under high irradiance stress. Increases in carotenoid concentrations would be expected to increase crop nutritional values.

  8. UV-B Radiation Impacts Shoot Tissue Pigment Composition in Allium fistulosum L. Cultigens

    Directory of Open Access Journals (Sweden)

    Kristin R. Abney

    2013-01-01

    Full Text Available Plants from the Allium genus are valued worldwide for culinary flavor and medicinal attributes. In this study, 16 cultigens of bunching onion (Allium fistulosum L. were grown in a glasshouse under filtered UV radiation (control or supplemental UV-B radiation [7.0 μmol·m−2·s−2 (2.68 W·m−2] to determine impacts on growth, physiological parameters, and nutritional quality. Supplemental UV-B radiation influenced shoot tissue carotenoid concentrations in some, but not all, of the bunching onions. Xanthophyll carotenoid pigments lutein and β-carotene and chlorophylls a and b in shoot tissues differed between UV-B radiation treatments and among cultigens. Cultigen “Pesoenyj” responded to supplemental UV-B radiation with increases in the ratio of zeaxanthin + antheraxanthin to zeaxanthin + antheraxanthin + violaxanthin, which may indicate a flux in the xanthophyll carotenoids towards deepoxydation, commonly found under high irradiance stress. Increases in carotenoid concentrations would be expected to increase crop nutritional values.

  9. How does radiative feedback from a UV background impact reionization?

    OpenAIRE

    Sobacchi, Emanuele; Mesinger, Andrei

    2013-01-01

    An ionizing UV background (UVB) inhibits gas accretion and photo-evaporates gas from the shallow potential wells of small, dwarf galaxies. During cosmological reionization, this effect can result in negative feedback: suppressing star-formation inside HII regions, thus impeding their continued growth. It is difficult to model this process, given the enormous range of scales involved. We tackle this problem using a tiered approach: combining parameterized results from single-halo collapse simu...

  10. The fascinating diatom frustule—can it play a role for attenuation of UV radiation?

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Lenau, Torben Anker; Lundholm, Nina

    2016-01-01

    size range as wave lengths of visible and ultraviolet (UV) light. This has prompted research into the possible role of the frustule in mediating light for the diatoms’ photosynthesis as well as into possible photonic applications of the diatom frustule. One of the possible biological roles, as well......Diatoms are ubiquitous organisms in aquatic environments and are estimated to be responsible for 20–25 % of the total global primary production. A unique feature of diatomsis the silica wall, called the frustule. The frustule is characterized by species-specific intricate nanopatterning in the same...... as area of potential application, is UV protection. In this review, we explore the possible adaptive value of the silica frustule with focus on research on the effect of UV radiation ondiatoms. We also explore the possible effect of the frustules on UV radiation, from a theoretical, biological...

  11. UV Radiation Induced Cross-Linking of Whey Protein Isolate-Based Films

    Directory of Open Access Journals (Sweden)

    Markus Schmid

    2017-01-01

    Full Text Available Casted whey protein films exposed to ultraviolet irradiation were analyzed for their cross-linking properties and mechanical and barrier performance. Expected mechanical and barrier improvements are discussed with regard to quantification of the cross-linking in the UV-treated whey protein films. Swelling tests were used to determine the degree of swelling, degree of cross-linking, and cross-linking density. When the UV radiation dosage was raised, a significant increase of the tensile strength as well as an increase in Young’s modulus was observed. No significant changes in water vapor and oxygen barrier properties between the UV-treated films and an untreated reference sample could be observed. The cross-linking density and the degree of cross-linking significantly increased due to UV radiation. Combined results indicate a disordered protein network in cast films showing locally free volume and therefore only minor mechanical and barrier improvements.

  12. UV Radiation Induced Cross-Linking of Whey Protein Isolate-Based Films

    OpenAIRE

    Schmid, Markus; Prinz, Tobias Konrad; Müller, Kerstin; Haas, Andreas

    2017-01-01

    Casted whey protein films exposed to ultraviolet irradiation were analyzed for their cross-linking properties and mechanical and barrier performance. Expected mechanical and barrier improvements are discussed with regard to quantification of the cross-linking in the UV-treated whey protein films. Swelling tests were used to determine the degree of swelling, degree of cross-linking, and cross-linking density. When the UV radiation dosage was raised, a significant increase of the tensile streng...

  13. Alterations of protein and DNA profiles of Zea mays L. under UV- B radiation

    OpenAIRE

    A. John De Britto; M. Jeevitha; T. Leon Stephan Raj

    2011-01-01

    UV radiation is an important stress factor for plants which may result in damage to genetic system and cell membranes and several metabolic processes. UV-B has greater damaging effects on plants because the cell macromolecules such as DNA and protein having strong absorption at 280-320 nm. In the present study, UV-B stress was given to the seeds of Zea mays L. at two different time intervals (30 and 60 min) and that stressed seeds were grown under normal environment condition. The leaves of 1...

  14. Kinetics of avoidance of simulated solar uv radiation by two arthropods

    Energy Technology Data Exchange (ETDEWEB)

    Barcelo, J.A.; Calkins, J.

    1980-12-01

    There is an increasing likelihood that the solar uv-B radiation (lambda = 280-320 nm) reaching the earth's surface will increase due to depletion of the stratospheric ozone layer. It is recognized that many organisms are insufficiently resistant to solar uv-B to withstand full summer sunlight and thus mechanisms which facilitate avoidance of solar uv-B exposure may have significance for the survival of sensitive species. There are many alternative pathways which would lead to avoidance of solar uv-B. We have investigated the dynamics of biological reactions to simulated solar uv-B radiation in two small arthropods, the two-spotted spider mite Tetranychus urticae Koch and the aquatic copepod Cyclops serrulatus. Observations of positioning and rate of movement were made; a mathematical formalism was developed which assisted in interpretation of the observations. Our observations suggest that, although avoidance would mitigate increased solar uv-B effects, even organisms which specifically reduce their uv-B exposure would encounter additional stress if ozone depletion does occur.

  15. UV radiation of the GTA welding plasma versus shielding gas composition

    Science.gov (United States)

    Ioffe, I.; Koss, V.; Perelman, N.; Hilton, D.

    1997-03-01

    UV radiation during gas tungsten arc (GTA) welding in argon/helium shielding gas mixtures versus gas composition and arc length has been investigated experimentally and theoretically. UV radiation was found to increase with an increase of argon concentration in the mixture. A physical model describing this phenomenon has been developed. The model predicts an increase in the total amount of ions in the mixture with an increase of argon concentration despite a decrease in plasma temperature. The result of calculations using the model is in satisfactory agreement with the experimental data.

  16. Effects of UV-B radiation on Olea europaea: comparisons between a greenhouse and a field experiment

    Energy Technology Data Exchange (ETDEWEB)

    Liakoura, V.; Stavrianakou, S.; Liakopoulos, G.; Karabourniotis, G. [Athens Agricultural Univ. Dept. of Agricultural Biotechnology, Athens (Greece); Manetas, Y. [Patras Univ, Dept, of Biology, Patras (Greece)

    1999-11-01

    Olea europaea plants were grown in the field with or without supplemental ultraviolet B radiation equivalent to the increase at ground level resulting from a 15 per cent depletion in stratospheric ozone concentration. After one year, their morphology, anatomy and physiology were compared with that of plants grown in a greenhouse and exposed for four months to either zero UV-B radiation or UV-B radiation equivalent to that of supplemented outdoor treatment. Results showed an increase in adaxial epidermal thickness and reduced total protein concentration in plants grown in the field, in contrast to greenhouse-grown plants which under the influence of UV-B radiation showed significant increases in abaxial cutical thickness and trichome UV-B absorbing compounds. These observations suggest that Olea europaea plants have a high UV-B tolerance and are not affected by increase in UV-B radiation. 23 refs., 1 tab.

  17. Design of autotrack detecting instrument for solar UV radiation

    Science.gov (United States)

    Xia, Jiangtao; Mao, Xiaoli; Zhao, Jing

    2009-11-01

    In order to autotrack the object and detect the solar UV index, a reliable real-time high-precise instrument is proposed in this paper. This instrument involves two subsystems: the autotrack and detecting modules. The autotrack module consists of four-quadrant photo detector, multi-channel signal processing circuit and precise stepping system. The detecting module designed for dada measurement and acquisition is made up of the ultraviolet sensor UV460 and high precision A/D converter MAX1162. The key component of the entire instrument is ultralow-power microprocessor MSP430 which is used for entire system controlling and data processing. The lower system of autotracking and measurement is communicated with upper PC computer by RS232 module. In the experiment, the tracking precision of two-dimensional motion revolving stage is calibrated to be less than 0.05°. Experimental results indicate that the system designed could realize the precise autotracking and detecting function well, and the measure precision of system has reached the desirable target.

  18. Effects of environmental and artificial UV-B radiation on freshwater prawn Macrobrachium olfersi embryos

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Evelise Maria [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil); Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Ammar, Dib [Universidade do Oeste de Santa Catarina, Departamento de Biologia, Campus Universitario, 89600-000 Joacaba, SC (Brazil); Bem, Andreza Fabro de; Latini, Alexandra [Universidade Federal de Santa Catarina, Departamento de Bioquimica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Mueller, Yara Maria Rauh [Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Allodi, Silvana, E-mail: sallodi@histo.ufrj.br [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil)

    2010-06-01

    The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth's surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310 mW cm{sup -2} UV-B for 30 min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of

  19. Inactivation of single-celled Ascaris suum eggs by low-pressure UV radiation.

    Science.gov (United States)

    Brownell, Sarah A; Nelson, Kara L

    2006-03-01

    Intact and decorticated single-celled Ascaris suum eggs were exposed to UV radiation from low-pressure, germicidal lamps at fluences (doses) ranging from 0 to 8,000 J/m2 for intact eggs and from 0 to 500 J/m2 for decorticated eggs. With a UV fluence of 500 J/m2, 0.44-+/-0.20-log inactivation (mean+/-95% confidence interval) (63.7%) of intact eggs was observed, while a fluence of 4,000 J/m2 resulted in 2.23-+/-0.49-log inactivation (99.4%). (The maximum quantifiable inactivation was 2.5 log units.) Thus, according to the methods used here, Ascaris eggs are the most UV-resistant water-related pathogen identified to date. For the range of fluences recommended for disinfecting drinking water and wastewater (200 to 2,000 J/m2), from 0- to 1.5-log inactivation can be expected, although at typical fluences (less than 1,000 J/m2), the inactivation may be less than 1 log. When the eggs were decorticated (the outer egg shell layers were removed with sodium hypochlorite, leaving only the lipoprotein ascaroside layer) before exposure to UV, 1.80-+/-0.32-log reduction (98.4%) was achieved with a fluence of 500 J/m2, suggesting that the outer eggshell layers protected A. suum eggs from inactivation by UV radiation. This protection may have been due to UV absorption by proteins in the outer layers of the 3- to 4-microm-thick eggshell. Stirring alone (without UV exposure) also inactivated some of the Ascaris eggs (approximately 20% after 75 min), which complicated determination of the inactivation caused by UV radiation alone.

  20. UV Radiation: a new first year physics/life sciences laboratory experiment

    Science.gov (United States)

    Petelina, S. V.; Siddaway, J. M.

    2010-12-01

    Unfortunately, Australia leads the world in the number of skin cancer cases per capita. Three major factors that contribute to this are: 1) the level of damaging ultraviolet (UV) radiation in Australia is higher than in many other countries. This is caused, among other factors, by the stratospheric ozone depletion and Antarctic ozone hole; 2) many people in Australia are of Irish-Scottish origin and their skin can not repair the damage caused by the UV radiation as effectively as the skin of people of other origins; 3) Australia is one of the world’s leaders in the outdoor activities where people tend to spend more time outside. As our experience has shown, most Australian University students, high school students, and even high school teachers were largely unaware of the UV damage details and effective safety measures. Therefore, a need for new ways to educate people became apparent. The general aim of this new 1st year laboratory experiment, developed and first offered at La Trobe University (Melbourne, Australia) in 2009, is to investigate how UV-B radiation levels change under various solar illumination conditions and how effective different types of protection are. After pre-lab readings on physical concepts and biological effects of UV radiation, and after solving all pre-lab problems, the students go outside and measure the actual change in UV-B and UV-A radiation levels under various conditions. Some of these conditions are: direct sun, shade from a building, shade under the roof, reflection from various surfaces, direct sun through cheap and expensive sunglasses and eyeglasses, direct sun through various types of cloth and hair. The equipment used is the UV-Probe manufactured by sglux SolGel Technologies GmbH. The students’ feedback on this new laboratory experiment was very positive. It was ranked top among all physics experiments offered as part of that subject (Physics for Life Sciences) in 2009 and top among all physics experiments presented for

  1. Growth under UV-B radiation increases tolerance to high-light stress in pea and bean plants

    NARCIS (Netherlands)

    Bolink, EM; van Schalkwijk, [No Value; Posthumus, F; van Hasselt, PR

    Pea (Pisum sativum L.) and bean (Phaseolus vulgaris L.) plants were exposed to enhanced levels of UV-B radiation in a growth chamber. Leaf discs of UV-B treated and control plants were exposed to high-light (HL) stress (PAR: 1200 mu mol m(-2) s(-1)) to study whether pre-treatment with UV-B affected

  2. Differential physiological and biochemical responses of two Vigna species under enhanced UV-B radiation

    Directory of Open Access Journals (Sweden)

    Rajiv Dwivedi

    2015-04-01

    Full Text Available Differential physiological and biochemical responses of two Vigna spp. i.e. Vigna mungo (L. and Vigna acontifolia (Jacq. seedlings exposed to enhanced ultraviolet-B (ambient+supplemental, 280–320 nm radiation were studied. UV-B radiation accelerated the generation of ROS i.e. superoxide radical (O2·−–, hydrogen peroxide (H2O2 and hydroxyl radical (·−OH in leaves, and concomitantly damaging effects on lipid peroxidation, electrolyte leakage and growth in both Vigna spp. were noticed in dose dependent manner, but V. mungo exhibited greater UV-B damaging effects. UV-B stress induced positive response on antioxidants: superoxide dismutase (SOD and guaiacol peroxidase (GPX activity, and contents of proline, ascorbic acid, total phenolic contents (TPCs and total flavonoid contents (TFCs in leaves of both spp., however, catalase (CAT exhibited varied activity. The study concludes that substantially higher contents of TPCs and TFCs in epidermal layer, proline and ascorbic acid, and higher CAT activity before and after enhanced UV-B exposure probably attributed greater tolerance to V. acontifolia species, thus exhibited lesser UV-B induced damaging effects on cellular components and growth than that of V. mungo. This study also suggests that V. acontifolia is comparatively resistant to UV-B and thus may be useful for practical cultivation.

  3. 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.

  4. Identification of genes responsive to solar simulated UV radiation in human monocyte-derived dendritic cells.

    Directory of Open Access Journals (Sweden)

    Hortensia de la Fuente

    Full Text Available Ultraviolet (UV irradiation has profound effects on the skin and the systemic immune system. Several effects of UV radiation on Dendritic cells (DCs functions have been described. However, gene expression changes induced by UV radiation in DCs have not been addressed before. In this report, we irradiated human monocyte-derived DCs with solar-simulated UVA/UVB and analyzed regulated genes on human whole genome arrays. Results were validated by RT-PCR and further analyzed by Gene Set Enrichment Analysis (GSEA. Solar-simulated UV radiation up-regulated expression of genes involved in cellular stress and inflammation, and down-regulated genes involved in chemotaxis, vesicular transport and RNA processing. Twenty four genes were selected for comparison by RT-PCR with similarly treated human primary keratinocytes and human melanocytes. Several genes involved in the regulation of the immune response were differentially regulated in UVA/UVB irradiated human monocyte-derived DCs, such as protein tyrosine phosphatase, receptor type E (PTPRE, thrombospondin-1 (THBS1, inducible costimulator ligand (ICOSL, galectins, Src-like adapter protein (SLA, IL-10 and CCR7. These results indicate that UV-exposure triggers the regulation of a complex gene repertoire involved in human-DC-mediated immune responses.

  5. Essential role of polyamines in restoration of DNA synthesis after UV radiation and expression of UV resistance in Cockayne syndrome cells.

    Science.gov (United States)

    Kusano, I; Hibasami, H; Kawai, K; Esaki, K; Shiraishi, T; Yatani, R

    1994-12-15

    Activity of ornithine decarboxylase (ODC) in Cockayne syndrome (CS) cells which were characterized by a delay of the recovery of DNA synthesis after 254 nm ultraviolet light (UV) radiation was extremely inhibited by UV, followed by a progressive decrease of putrescine. When putrescine was added in the cultures, CS cells showed a rapid recovery in DNA synthesis and also an expression of UV-resistance as seen in normal cells. Thus, ODC induction system of CS cells is highly sensitive to UV. Considering current hot spots in DNA repair, our results probably reflect a defect of preferentially rapid repair in ODC gene of CS cells.

  6. Temperature dependence of UV radiation effects in Arctic and temperate isolates of three red macrophytes

    NARCIS (Netherlands)

    van de Poll, W.H.; Eggert, A.; Buma, A.G.J.; Breeman, Arno

    The temperature dependence of UV effects was studied for Arctic and temperate isolates of the red macrophytes Palmaria palmata, Coccotylus truncatus and Phycodrys rubens. The effects of daily repeated artificial ultraviolet B and A radiation (UVBR: 280-320 nm, UVAR: 320-400 nm) treatments were

  7. Ambient solar UV radiation and seasonal trends in potential sunburn risk among schoolchildren in South Africa

    CSIR Research Space (South Africa)

    Wright, CY

    2011-07-01

    Full Text Available and African albinos, and people spending extended unprotected periods outdoors are at risk of sunburn, a risk factor for skin cancer. Sunburn becomes increasingly likely during the high solar UV radiation hours around midday, and previous studies have shown...

  8. ATTENUATION OF SOLAR UV RADIATION BY AEROSOLS DURING AIR POLLUTION EPISODES

    Science.gov (United States)

    Increase in the amount of solar UV radiation reaching the surface due to decrease in stratospheric ozone continues to be a major concern (WMO, 1998). However, recent studies show that absorption and smattering by aerosols during air pollution episode decreases the amount of radi...

  9. Performance Analysis of Si-Based Ultra-Shallow Junction Photodiodes for UV Radiation Detection

    NARCIS (Netherlands)

    Shi, L.

    2013-01-01

    This thesis presents a performance investigation of newly-developed ultra-shallow junction photodiodes (PureB-diodes) for ultraviolet (UV) radiation detection. The photodiodes are fabricated by pure boron chemical vapor deposition (PureB CVD) technology, which can provide nanometer-thin boron

  10. Effects of enhanced UV-B radiation on nitrogen fixation in arctic ecosystems.

    NARCIS (Netherlands)

    Solheim, B.; Zielke, M.; Bjerke, J.W.; Rozema, J.

    2006-01-01

    Recent global climate models predict a further significant loss of ozone in the next decades, with up to 50% depletion of the ozone layer over large parts of the Arctic resulting in an increase in ultraviolet-B radiation (UV-B) (280-315 nm) reaching the surface of the Earth. The percentage of total

  11. Evolution of organic molecules under Mars-like UV radiation conditions in space and laboratory

    Science.gov (United States)

    Rouquette, L.; Stalport, F.; Cottin, H.; Coll, P.; Szopa, C.; Saiagh, K.; Poch, O.; Khalaf, D.; Chaput, D.; Grira, K.; Dequaire, T.

    2017-09-01

    The detection and identification of organic molecules at Mars are of prime importance, as some of these molecules are life precursors and components. While in situ planetary missions are searching for them, it is essential to understand how organic molecules evolve and are preserved at the surface of Mars. Indeed the harsh conditions of the environment of Mars such as ultraviolet (UV) radiation or oxidative processes could explain the low abundance and diversity of organic molecules detected by now [1]. In order to get a better understanding of the evolution of organic matter at the surface of Mars, we exposed organic molecules under a Mars-like UV radiation environment. Similar organic samples were exposed to the Sun radiation, outside the International Space Station (ISS), and under a UV lamp (martian pressure and temperature conditions) in the laboratory. In both experiments, organic molecules tend to photodegrade under Mars-like UV radiation. Minerals, depending on their nature, can protect or accelerate the degradation of organic molecules. For some molecules, new products, possibly photoresistant, seem to be produced. Finally, experimenting in space allow us to get close to in situ conditions and to validate our laboratory experiment while the laboratory experiment is essential to study the evolution of a large amount and diversity of organic molecules.

  12. Photocatalytic ROS production and phototoxicity of titanium dioxide nanoparticles is dependent on solar UV radiation spectrum

    Science.gov (United States)

    Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO2) and its consequent phototoxicity to Daphnia magna were measured under different solar UV radiation spectrum by applying a series of optical filters in a solar simulator. Removing UVB (280-32...

  13. Comparison of the effects of UV-A radiation on Leptospira interrogan ...

    African Journals Online (AJOL)

    USER

    2010-05-24

    May 24, 2010 ... Interestingly, Cullen and co-workers found that by applying thermal stress on pathogenic Leptospira serovar Lai, varying the temperature at 20, 30 and 37°C, the lipL48 was unaffected (Haake and Matsunaga, 2002). This finding suggests that 48-kDa could be damaged by UV-A radiation not by heat ...

  14. Observation of two-photon absorption at UV radiation in ZnS ...

    Indian Academy of Sciences (India)

    2014-02-12

    Feb 12, 2014 ... UV radiation. The sample used in this work is freshly prepared by following the chemi- cal precipitation method as elaborated in [6]. UV–visible absorption characteristic of the sample, measured by a spectrophotometer (Hitachi U-3010) are shown as the left inset of figure 1 [6]. The average particle size ...

  15. Attenuation of biologically effective UV radiation in tropical Atlantic waters measured with a biochemical DNA dosimeter

    NARCIS (Netherlands)

    Boelen, P.; Obernosterer, I; Vink, A.A; Buma, A.G.J.

    A biochemical dosimeter was developed to study the attenuation of biologically effective UV radiation in marine tropical waters. Small quartz vials were used containing a solution of DNA molecules; the vials were incubated at discrete water depths. Subsequently, DNA damage was determined in these

  16. Comparison of the effects of UV-A radiation on Leptospira interrogan ...

    African Journals Online (AJOL)

    USER

    2010-05-24

    May 24, 2010 ... Full Length Research Paper. Comparison of the effects of UV-A radiation on. Leptospira interrogan serovar Bataviae, Canicola and. Pomona. Sudarat Chadsuthi1, Jirasak Wong-ekkabut1,2, Wannapong Triampo1,3,6*, Galayanee. Doungchawee4 and Darapond Triampo1,3,5,6. 1Group of Biological and ...

  17. Attenuation of biologically effective UV radiation in tropical atlantic waters measured with a biochemical DNA dosimeter

    NARCIS (Netherlands)

    Boelen, P.; Obernosterer, I.; Vink, A.A.; Buma, A.G.J.

    1999-01-01

    A biochemical dosimeter was developed to study the attenuation of biologically effective UV radiation in marine tropical waters. Small quartz vials were used containing a solution of DNA molecules; the vials were incubated at discrete water depths. Subsequently, DNA damage was determined in these

  18. Validity of satellite measurements used for the monitoring of UV radiation risk on health

    Directory of Open Access Journals (Sweden)

    F. Jégou

    2011-12-01

    Full Text Available In order to test the validity of ultraviolet index (UVI satellite products and UVI model simulations for general public information, intercomparison involving three satellite instruments (SCIAMACHY, OMI and GOME-2, the Chemistry and Transport Model, Modélisation de la Chimie Atmosphérique Grande Echelle (MOCAGE, and ground-based instruments was performed in 2008 and 2009. The intercomparison highlighted a systematic high bias of ~1 UVI in the OMI clear-sky products compared to the SCIAMACHY and TUV model clear-sky products. The OMI and GOME-2 all-sky products are close to the ground-based observations with a low 6 % positive bias, comparable to the results found during the satellite validation campaigns. This result shows that OMI and GOME-2 all-sky products are well appropriate to evaluate the UV-risk on health. The study has pointed out the difficulty to take into account either in the retrieval algorithms or in the models, the large spatial and temporal cloud modification effect on UV radiation. This factor is crucial to provide good quality UV information. OMI and GOME-2 show a realistic UV variability as a function of the cloud cover. Nevertheless these satellite products do not sufficiently take into account the radiation reflected by clouds. MOCAGE numerical forecasts show good results during periods with low cloud covers, but are actually not adequate for overcast conditions; this is why Météo-France currently uses human-expertised cloudiness (rather than direct outputs from Numerical Prediction Models together with MOCAGE clear-sky UV indices for its operational forecasts. From now on, the UV monitoring could be done using free satellite products (OMI, GOME-2 and operational forecast for general public by using modelling, as long as cloud forecasts and the parametrisation of the impact of cloudiness on UV radiation are adequate.

  19. Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen

    DEFF Research Database (Denmark)

    Bruhn, Dan; Mikkelsen, Teis Nørgaard; Rolsted, M. M. M.

    2014-01-01

    layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we......The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax...... investigated the potential of the leaf surface wax itself as a source of UV radiationinduced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation...

  20. UV radiation-induced immunosuppression is greater in men and prevented by topical nicotinamide.

    Science.gov (United States)

    Damian, Diona L; Patterson, Clare R S; Stapelberg, Michael; Park, Joohong; Barnetson, Ross St C; Halliday, Gary M

    2008-02-01

    UV radiation-induced immunosuppression augments cutaneous carcinogenesis. The incidence of skin cancer continues to increase despite increased use of sunscreens, which are less effective at preventing immunosuppression than sunburn. Using the Mantoux reaction as a model of skin immunity, we investigated the effects of solar-simulated (ss) UV and its component UVA and UVB wavebands and tested the ability of topical nicotinamide to protect from UV-induced immunosuppression. Healthy, Mantoux-positive volunteers were UV-irradiated on their backs, with 5% nicotinamide or vehicle applied to different sites in a randomized, double-blinded manner. Subsequent Mantoux testing at irradiated and adjacent unirradiated sites enabled measurement of UV-induced immunosuppression with and without nicotinamide. Suberythemal ssUV caused significant immunosuppression, although component UVB and UVA doses delivered independently did not. Men were immunosuppressed by ssUV doses three times lower than those required to immunosuppress women. This may be an important cause of the higher skin cancer incidence and mortality observed in men. Topical nicotinamide prevented immunosuppression, with gene chip microarrays suggesting that the mechanisms of protection may include alterations in complement, energy metabolism and apoptosis pathways. Nicotinamide is a safe and inexpensive compound that could be added to sunscreens or after-sun lotions to improve protection from immunosuppression. immunosuppression.JID JOURNAL CLUB ARTICLE: For questions, answers, and open discussion about this article, please go to http://network.nature.com/group/jidclub

  1. Generation of UV radiation by vapors of complex molecules

    Energy Technology Data Exchange (ETDEWEB)

    Barkova, L.A.; Gruzinskii, V.V.; Danilova, V.I.; Degtiarenko, K.M.; Kopylova, T.N.; Kuznetsov, A.L.

    1981-08-01

    Laser action has been obtained in the following organic compounds under pumping by XeCl excimer laser radiation at 308 nm: para-terphenyl, 2-phenylbenzoxazole, 2-(n-tolyl)-benzoxaxole, 2-(n-methoxyphenyl)-benzoxazole, 2-(n-dimethylaminophenyl)-benzoxazole, 2-biphenylbenzoxazole, (2-alpha-naphthyl)-benzoxazole, 1.4-di(n-phenylethynyl)-benzole, and paraquaterphenyl. The nontuning lasing bands covered the range of 330-370 nm, and the most short-wavelength maximum (333.5 nm) was found for 2(n-methoxyphenyl)-benzoxazole. The lasing capability of the molecules was analyzed.

  2. Extremely high UV-C radiation resistant microorganisms from desert environments with different manganese concentrations.

    Science.gov (United States)

    Paulino-Lima, Ivan Glaucio; Fujishima, Kosuke; Navarrete, Jesica Urbina; Galante, Douglas; Rodrigues, Fabio; Azua-Bustos, Armando; Rothschild, Lynn Justine

    2016-10-01

    Desiccation resistance and a high intracellular Mn/Fe ratio contribute to ionizing radiation resistance of Deinococcus radiodurans. We hypothesized that this was a general phenomenon and thus developed a strategy to search for highly radiation-resistant organisms based on their natural environment. While desiccation is a typical feature of deserts, the correlation between radiation resistance and the intracellular Mn/Fe ratio of indigenous microorganisms or the Mn/Fe ratio of the environment, has not yet been described. UV-C radiation is highly damaging to biomolecules including DNA. It was used in this study as a selective tool because of its relevance to early life on earth, high altitude aerobiology and the search for life beyond Earth. Surface soil samples were collected from the Sonoran Desert, Arizona (USA), from the Atacama Desert in Chile and from a manganese mine in northern Argentina. Microbial isolates were selected after exposure to UV-C irradiation and growth. The isolates comprised 28 genera grouped within six phyla, which we ranked according to their resistance to UV-C irradiation. Survival curves were performed for the most resistant isolates and correlated with their intracellular Mn/Fe ratio, which was determined by ICP-MS. Five percent of the isolates were highly resistant, including one more resistant than D. radiodurans, a bacterium generally considered the most radiation-resistant organism, thus used as a model for radiation resistance studies. No correlation was observed between the occurrence of resistant microorganisms and the Mn/Fe ratio in the soil samples. However, all resistant isolates showed an intracellular Mn/Fe ratio much higher than the sensitive isolates. Our findings could represent a new front in efforts to harness mechanisms of UV-C radiation resistance from extreme environments. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The genotoxic effects of DNA lesions induced by artificial UV-radiation and sunlight.

    Science.gov (United States)

    Schuch, André Passaglia; Menck, Carlos Frederico Martins

    2010-06-01

    Solar radiation sustains and affects all life forms on Earth. The increase in solar UV-radiation at environmental levels, due to depletion of the stratospheric ozone layer, highlights serious issues of social concern. This becomes still more dramatic in tropical and subtropical regions where radiation-intensity is still higher. Thus, there is the need to evaluate the harmful effects of solar UV-radiation on the DNA molecule as a basis for assessing the risks involved for human health, biological productivity and ecosystems. In order to evaluate the profile of DNA damage induced by this form of radiation and its genotoxic effects, plasmid DNA samples were exposed to artificial-UV lamps and directly to sunlight. The induction of cyclobutane pyrimidine dimer photoproducts (CPDs) and oxidative DNA damage in these molecules were evaluated by means of specific DNA repair enzymes. On the other hand, the biological effects of such lesions were determined through the analysis of the DNA inactivation rate and mutation frequency, after replication of the damaged pCMUT vector in an Escherichia coliMBL50 strain. The results indicated the induction of a significant number of CPDs after exposure to increasing doses of UVC, UVB, UVA radiation and sunlight. Interestingly, these photoproducts are those lesions that better correlate with plasmid inactivation as well as mutagenesis, and the oxidative DNA damages induced present very low correlation with these effects. The results indicated that DNA photoproducts play the main role in the induction of genotoxic effects by artificial UV-radiation sources and sunlight. 2010 Elsevier B.V. All rights reserved.

  4. Study of mechanical behavior of PMMA in bending and after UV irradiation and gamma radiation; Estudo do comportamento mecanico do PMMA sob flexao apos irradiacao UV e gama

    Energy Technology Data Exchange (ETDEWEB)

    Todt, M.L.; Kienen, V.D.; Azevedo, E.C., E-mail: helunica@yahoo.com.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2014-07-01

    PMMA is a polymer that has density similar to water and refractive index alike to glass. It has been used in the substitution to roofing tiles and coverages, affording to be exposed to UV radiation and gamma radiation. This paper had the objective to study the effect in the flexural proprieties of the PMMA exposed to these types of radiations and the evaluation of the wettability through a contact angle measurer. The PMMA specimens have been submitted to 1500 h of UVA radiation, 1500 h of UVC radiation and to 25kGy of gamma radiation. The results show that the PMMA. (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-BBE 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. Radiation damage and repair in cells and cell components. Progress report, November 1, 1977--October 31, 1978. [Uv and x radiation, bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Fluke, D.J.; Pollard, E.C.

    1978-01-01

    Progress is reported on the following research projects: coordinate induction of mutagenesis, radioresistance, and inhibition of post-radiation DNA degradation; radioinduced filamentation; action spectrum for induction of K12 lambda phage; effects of uv radiation on cells in the frozen state; dependence of mutagenesis on wavelength of uv; and w-reactivation of x-irradiated phage lambda. (HLW)

  7. The changes in quality ingredients of Qi chrysanthemum flowers treated with elevated UV-B radiation at different growth stages.

    Science.gov (United States)

    Yao, Xiaoqin; Chu, Jianzhou; He, Xueli; Ma, Chunhui; Han, Chao; Shen, Haiyu

    2015-05-01

    The paper mainly reported the changes in quality ingredients of Qi chrysanthemum flowers treated with elevated UV-B radiation at different growth stages. The experiment included two levels of UV-B radiation (ambient UV-B, a 10% increase in ambient UV-B). Elevated UV-B radiation was carried out for 10-days during seedling, vigorous growth, bud and flower stages of Qi chrysanthemum, respectively. Elevated UV-B treatments applied during four development stages did not significantly affect flower yield, the rate of superoxide radical production and malondialdehyde concentration in flowers, while increased free amino acid concentration. The amino acid concentration induced by elevated UV-B radiation applied during bud stage was higher than that during the other stages. Elevated UV-B radiation applied during vigorous growth (except for flavone), bud and flower stages of chrysanthemum significantly increased hydrogen peroxide concentration, phenylalanine ammonia lyase enzyme activity, vitamin C, chlorogenic acid and flavone concentrations in flowers. These results suggested that active and nutritional ingredients in flowers of chrysanthemum could be increased by elevated UV-B radiation applied during the later growth stages of chrysanthemum. The paper supplied a simple and environmental-friendly method to improve quality of medicinal plants. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Compression zone of a magnetoplasma compressor as a source of extreme UV radiation

    Science.gov (United States)

    Garkusha, I. E.; Chebotarev, V. V.; Solyakov, D. G.; Petrov, Yu. V.; Ladygina, M. S.; Marchenko, A. K.; Staltsov, V. V.; Yelisyeyev, D. V.

    2012-02-01

    Results from experimental studies of extreme UV (EUV) radiation from the compression zone of a magnetoplasma compressor (MPC) operating with xenon are presented. Two MPC operating modes that differ in the method of xenon injection into the discharge were studied. It is shown that EUV radiation in the wavelength range of 5-80 nm is emitted from the compression zone. In the MPC operating mode with local xenon injection directly into the compression zone surrounded by helium plasma, the radiation power reaches it peak value of 16-18 kW in the wavelength range of 12.2-15.8 nm.

  9. Compression zone of a magnetoplasma compressor as a source of extreme UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I. E.; Chebotarev, V. V.; Solyakov, D. G.; Petrov, Yu. V.; Ladygina, M. S.; Marchenko, A. K.; Staltsov, V. V.; Yelisyeyev, D. V. [National Academy of Sciences of Ukraine, Institute of Plasma Physics, National Science Center ' Kharkiv Institute of Physics and Technology,' (Ukraine)

    2012-02-15

    Results from experimental studies of extreme UV (EUV) radiation from the compression zone of a magnetoplasma compressor (MPC) operating with xenon are presented. Two MPC operating modes that differ in the method of xenon injection into the discharge were studied. It is shown that EUV radiation in the wavelength range of 5-80 nm is emitted from the compression zone. In the MPC operating mode with local xenon injection directly into the compression zone surrounded by helium plasma, the radiation power reaches it peak value of 16-18 kW in the wavelength range of 12.2-15.8 nm.

  10. Rapid enzymatic response to compensate UV radiation in copepods.

    Directory of Open Access Journals (Sweden)

    María Sol Souza

    Full Text Available Ultraviolet radiation (UVR causes physical damage to DNA, carboxylation of proteins and peroxidation of lipids in copepod crustaceans, ubiquitous and abundant secondary producers in most aquatic ecosystems. Copepod adaptations for long duration exposures include changes in behaviour, changes in pigmentation and ultimately changes in morphology. Adaptations to short-term exposures are little studied. Here we show that short-duration exposure to UVR causes the freshwater calanoid copepod, Eudiaptomus gracilis, to rapidly activate production of enzymes that prevent widespread collateral peroxidation (glutathione S-transferase, GST, that regulate apoptosis cell death (Caspase-3, Casp-3, and that facilitate neurotransmissions (cholinesterase-ChE. None of these enzyme systems is alone sufficient, but they act in concert to reduce the stress level of the organism. The interplay among enzymatic responses provides useful information on how organisms respond to environmental stressors acting on short time scales.

  11. Solar Extreme UV radiation and quark nugget dark matter model

    Science.gov (United States)

    Zhitnitsky, Ariel

    2017-10-01

    We advocate the idea that the surprising emission of extreme ultra violet (EUV) radiation and soft x-rays from the Sun are powered externally by incident dark matter (DM) particles. The energy and the spectral shape of this otherwise unexpected solar irradiation is estimated within the quark nugget dark matter model. This model was originally invented as a natural explanation of the observed ratio Ωdark ~ Ωvisible when the DM and visible matter densities assume the same order of magnitude values. This generic consequence of the model is a result of the common origin of both types of matter which are formed during the same QCD transition and both proportional to the same fundamental dimensional parameter ΛQCD. We also present arguments suggesting that the transient brightening-like "nanoflares" in the Sun may be related to the annihilation events which inevitably occur in the solar atmosphere within this dark matter scenario.

  12. Photostability study of commercial sunscreens submitted to artificial UV irradiation and/or fluorescent radiation.

    Science.gov (United States)

    Romanhole, Rodrigo Colina; Ataide, Janaina Artem; Cefali, Leticia Caramori; Moriel, Patricia; Mazzola, Priscila Gava

    2016-09-01

    Sunscreens contain molecules with the ability to absorb and/or reflect UVA (ultraviolet A) and UVB (ultraviolet B) radiation, thereby preventing this radiation from reaching the epidermis or dermis. Their photo stabilities after exposure to UV radiation are well known and described, but there is little data on the stability of these filters after fluorescent indoors light radiation, such as from light emitted by commercial lamps present in homes and offices. Those lamps can expose people to varying levels of UVB, UVA, visible light, and IR (infrared). This study assesses the photostability of four different commercial products containing chemical sun filters after artificial UV and fluorescent irradiation, correlating the UVB and UVA absorption efficiencies of each product against the different types of radiation. The tested products were applied on a plate of polymethylmethacrylate (PMMA) and irradiated by a solar simulator with specific filters for UVA and UVB and a commercial fluorescent light source. According to the results, three formulations did not show photostability, suffering significant changes in their UV absorption spectra, and one of the selected formulations can be considered photostable. This reinforces the importance of conducting stability studies for sunscreen formulations in different conditions, including under artificial (indoor) light exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Separate and combined responses to water deficit and UV-B radiation.

    Science.gov (United States)

    Bandurska, Hanna; Niedziela, Justyna; Chadzinikolau, Tamara

    2013-12-01

    Crops and other plants in natural conditions are routinely affected by several stresses acting simultaneously or in sequence. In areas affected by drought, plants may also be exposed to enhanced UV-B radiation (280-315nm). Each of these stress factors differently affects cellular metabolism. A common consequence of plant exposure to the separate action of water deficit and UV-B radiation is the enhanced generation of reactive oxygen species (ROS) causing damage to proteins, lipids, carbohydrates and DNA. Despite this destructive activity, ROS also act as signalling molecules in cellular processes responsible for defence responses. Plants have evolved many physiological and biochemical mechanisms that avoid or tolerate the effects of stress factors. Water deficit avoidance leads to stomatal closure, stimulation of root growth, and accumulation of free proline and other osmolytes. Secondary metabolites (flavonols, flavones and anthocyanins) that accumulate in epidermal cells effectively screen UV-B irradiation and reduce its penetration to mesophyll tissue. The coordinated increased activity of the enzymatic antioxidant defence system such as up-regulation of superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase and glutathione reductase is an important mechanism of tolerance to water deficit and UV-B radiation. The accumulation of low molecular antioxidants (proline, glycine betaine, ascorbate and glutathione) can also contribute to tolerance to water deficit. Polyamines, tocopherol, carotenoids, alkaloids, flavonoids and other secondary metabolites participate in the removal of ROS under conditions of increased UV-B radiation. The combination of water deficit and UV-B radiation induces responses that can be antagonistic, additive or synergistic in comparison with the action of single stresses. UV-B radiation may enhance resistance to water deficit and vice versa. Hydrogen peroxide, nitric oxide (NO), abscisic acid (ABA), jasmonic acid, ethylene

  14. Modeling the photodegradation of emerging contaminants in waters by UV radiation and UV/H2O2 system.

    Science.gov (United States)

    Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Rodriguez, Elena

    2013-01-01

    Five emerging contaminants (1-H-Benzotriazole, N,N-diethyl-m-toluamide or DEET, Chlorophene, 3-Methylindole, and Nortriptyline HCl), frequently found in surface waters and wastewaters, were selected to be photooxidized in several water matrices. Previous degradation experiments of these compounds individually dissolved in ultra pure water were performed by using UV radiation at 254 nm and the Fenton's reagent. These oxidation systems allowed the determination of the quantum yields and the rate constants for the radical reaction between each compound and hydroxyl radicals. Later, the simultaneous photodegradation of mixtures of the selected ECs in several types of water (ultrapure water, reservoir water, and two effluents from WWTPs) was carried out and a kinetic study was conducted. A model is proposed for the ECs elimination, and the theoretically calculated concentrations with this model agreed well with the experimental results obtained, which confirmed that it constitutes an excellent tool to predict the elimination of these compounds in waters.

  15. Past Changes in Arctic Terrestrial Ecosystems, Climate and UV Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Callaghan, Terry V. [Abisko Scientific Research Station, Abisko (Sweden); Bjoern, Lars Olof [Lund Univ. (Sweden). Dept. of Cell and Organism Biology; Chernov, Yuri [Russian Academy of Sciences, Moscow (Russian Federation). A.N. Severtsov Inst. of Evolutionary Morphology and Animal Ecology] (and others)

    2004-11-01

    conditions that are apparently without precedent during the Pleistocene is likely to be considerable, particularly as their exposure to co-occurring environmental changes (such as enhanced levels of UV-B, deposition of nitrogen compounds from the atmosphere, heavy metal and acidic pollution, radioactive contamination, increased habitat fragmentation) is also without precedent.

  16. The Ultraviolet radiation (UV-C for the microbiological stabilization of red wine

    Directory of Open Access Journals (Sweden)

    Matias Fábio

    2016-01-01

    Full Text Available The traditional procedure for the control of the microbiological stability of wine consists of the addition of sulfur dioxide (SO2, which acts as an antimicrobial agent and also as an antioxidant. The search for alternative methods of microbiological control is important and necessary, since SO2 is a potential allergen and consumers are increasingly looking for healthier and preservative free products. Ultraviolet radiation was tested as an innovative technology that can help reduce the amount of sulphur dioxide used in winemaking. The object of this study was to optimize the process conditions compared to the results obtained previously, and to evaluate the efficiency of microbiological stabilization and its influence on the physico-chemical characteristics, the phenolic composition and sensory profile. Thus, red wine with very low content of sulphur dioxide was subjected to UV-C radiation in two different doses 424J/l e 778J/l, and the preparation of a control wine was carried out to which 30 mg/l sulfur dioxide was added. The wines (control=UV0, UV1 and UV2 were analyzed over time (from 0 to 4 months. The results show that treatment with a lower dosage is effective in the microbiological control of the product. The wines subjected to treatment with UV-C showed an increase in intensity of colour, and the treatment does not affect the flavour and taste of the wine.

  17. Long-term variations of the UV-B radiation over Central Europe as derived from the reconstructed UV time series

    Directory of Open Access Journals (Sweden)

    J. W. Krzyscin

    2004-04-01

    Full Text Available The daily doses of the erythemally weighted UV radiation are reconstructed for three sites in Central Europe: Belsk-Poland (1966–2001, Hradec Kralove-Czech Republic (1964–2001, and Tõravere-Estonia (1967–2001 to discuss the UV climatology and the long-term changes of the UV-B radiation since the mid 1960s. Various reconstruction models are examined: a purely statistical model based on the Multivariate Adaptive Regression Splines (MARS methodology, and a hybrid model combining radiative transfer model calculations with empirical estimates of the cloud effects on the UV radiation. Modeled long-term variations of the surface UV doses appear to be in a reasonable agreement with the observed ones. A simple quality control procedure is proposed to check the homogeneity of the biometer and pyranometer data. The models are verified using the results of UV observations carried out at Belsk since 1976. MARS provides the best estimates of the UV doses, giving a mean difference between the modeled and observed monthly means equal to 0.6±2.5%. The basic findings are: similar climatological forcing by clouds for all considered stations (~30% reduction in the surface UV, long-term variations in UV monthly doses having the same temporal pattern for all stations with extreme low monthly values (~5% below overall mean level at the end of the 1970s and extreme high monthly values (~5% above overall mean level in the mid 1990s, regional peculiarities in the cloud long-term forcing sometimes leading to extended periods with elevated UV doses, recent stabilization of the ozone induced UV long-term changes being a response to a trendless tendency of total ozone since the mid 1990s. In the case of the slowdown of the total ozone trend over Northern Hemisphere mid-latitudes it seems that clouds will appear as the most important modulator of the UV radiation both in long- and short-time scales over next decades.

    Key words. Atmospheric composition and

  18. Long-term variations of the UV-B radiation over Central Europe as derived from the reconstructed UV time series

    Directory of Open Access Journals (Sweden)

    J. W. Krzyscin

    2004-04-01

    Full Text Available The daily doses of the erythemally weighted UV radiation are reconstructed for three sites in Central Europe: Belsk-Poland (1966–2001, Hradec Kralove-Czech Republic (1964–2001, and Tõravere-Estonia (1967–2001 to discuss the UV climatology and the long-term changes of the UV-B radiation since the mid 1960s. Various reconstruction models are examined: a purely statistical model based on the Multivariate Adaptive Regression Splines (MARS methodology, and a hybrid model combining radiative transfer model calculations with empirical estimates of the cloud effects on the UV radiation. Modeled long-term variations of the surface UV doses appear to be in a reasonable agreement with the observed ones. A simple quality control procedure is proposed to check the homogeneity of the biometer and pyranometer data. The models are verified using the results of UV observations carried out at Belsk since 1976. MARS provides the best estimates of the UV doses, giving a mean difference between the modeled and observed monthly means equal to 0.6±2.5%. The basic findings are: similar climatological forcing by clouds for all considered stations (~30% reduction in the surface UV, long-term variations in UV monthly doses having the same temporal pattern for all stations with extreme low monthly values (~5% below overall mean level at the end of the 1970s and extreme high monthly values (~5% above overall mean level in the mid 1990s, regional peculiarities in the cloud long-term forcing sometimes leading to extended periods with elevated UV doses, recent stabilization of the ozone induced UV long-term changes being a response to a trendless tendency of total ozone since the mid 1990s. In the case of the slowdown of the total ozone trend over Northern Hemisphere mid-latitudes it seems that clouds will appear as the most important modulator of the UV radiation both in long- and short-time scales over next decades. Key words. Atmospheric composition and structure

  19. From ozone depletion to agriculture: understanding the role of UV radiation in sustainable crop production.

    Science.gov (United States)

    Wargent, Jason J; Jordan, Brian R

    2013-03-01

    Largely because of concerns regarding global climate change, there is a burgeoning interest in the application of fundamental scientific knowledge in order to better exploit environmental cues in the achievement of desirable endpoints in crop production. Ultraviolet (UV) radiation is an energetic driver of a diverse range of plant responses and, despite historical concerns regarding the damaging consequences of UV-B radiation for global plant productivity as related to stratospheric ozone depletion, current developments representative of a range of organizational scales suggest that key plant responses to UV-B radiation may be exploitable in the context of a sustainable contribution towards the strengthening of global crop production, including alterations in secondary metabolism, enhanced photoprotection, up-regulation of the antioxidative response and modified resistance to pest and disease attack. Here, we discuss the prospect of this paradigm shift in photobiology, and consider the linkages between fundamental plant biology and crop-level outcomes that can be applied to the plant UV-B response, in addition to the consequences for related biota and many other facets of agro-ecosystem processes. © 2013 The Author. New Phytologist © 2012 New Phytologist Trust.

  20. Shading areas, sky-view factor and UV radiation in urban canopy of Moscow city

    Science.gov (United States)

    Konstantinov, P. I.; Samsonov, T. E.; Zhdanova, E. Yu.; Chubarova, N. Ye.

    2017-02-01

    The main goal of this investigation is to develop a kind of "urban reanalysis" - the database of meteorological and radiation fields under Moscow megalopolis with high spatial resolution. Sky View Factor (SVF) is widely used for evaluating the solar irradiance attenuation in urban canopy. In this study we suggested raster-based calculation of SVF. We applied this technique for evaluating specific features in UV irradiance at Moscow megalopolis conditions. We showed that relative frequency of SVF over the territory of Moscow higher than 80% is observed in more than 86% of cases. The maps of UV losses due to sky obscuring over the territory of Moscow have been obtained for different seasons.

  1. Alterations of protein and DNA profiles of Zea mays L. under UV- B radiation

    Directory of Open Access Journals (Sweden)

    A. John De Britto

    2011-12-01

    Full Text Available UV radiation is an important stress factor for plants which may result in damage to genetic system and cell membranes and several metabolic processes. UV-B has greater damaging effects on plants because the cell macromolecules such as DNA and protein having strong absorption at 280-320 nm. In the present study, UV-B stress was given to the seeds of Zea mays L. at two different time intervals (30 and 60 min and that stressed seeds were grown under normal environment condition. The leaves of 10th and 20th day seedlings were collected for the analysis of protein and DNA profiles. Protein was analyzed by SDS-PAGE and DNA was analyzed by Restriction enzymes. When compared with control plants, increased numbers of protein and DNA bands were observed in UV-B treated plants. The present study concluded that the plant synthesis new proteins and DNA under UV treatment for the adaptation to the environmental conditions. These stressed proteins could be used as biomarkers for identification of stressed plant. Identification of quantitative trait loci for UV stress resistance may well be an effective analytical tool. This approach is promising, considering that saturated DNA marker maps are now available for both genetic model plants and crop plants.

  2. 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.

  3. Effects of Reducing the Ambient UV-B Radiation in the High Arctic on Salix arctica and Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, Kristian; Ro-Poulsen, Helge; Mikkelsen, Teis Nørgaard

    2005-01-01

    , transmitting ¿ > 400 nm) were used to reduce UV-B radiation and UV-B+A respectively. A UV transparent film (Teflon, transmitting ¿ > 280 nm) and no film were used as controls. Field measurements showed that the plants under Teflon, Mylar and Lexan received app. 91%, 39% and 17% of the ambient UV-B irradiance......Effects of reducing the ambient UV-B radiation on gas exchange and chlorophyll fluores-cence of two dwarf shrub species, Salix arctica and Vaccinium uliginosum, was studied in a high arctic heath in North East Greenland during two growing seasons. Films (Mylar, transmitting ¿ > 320 nm, and Lexan......, respectively. UV radiation decreased the maximal photochemical efficiency (Fv/Fm) and other fast fluorescence transient derived parameters in both species, despite an increased level of leaf flavonoid content. The responses varied in signifi-cance according to species and site. The relation of these effects...

  4. Effects of reducing the ambient UV-B radiation in the high Arctic on Salix arctica and Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, K.R.; Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard

    2005-01-01

    , transmitting λ > 400 nm) were used to reduce UV-B radiation and UV-B+A respectively. A UV transparent film (Teflon, transmitting λ > 280 nm) and no film were used as controls. Field measurements showed that the plants under Teflon, Mylar and Lexan received app. 91%, 39% and 17% of the ambient UV-B irradiance......Effects of reducing the ambient UV-B radiation on gas exchange and chlorophyll fluores-cence of two dwarf shrub species, Salix arctica and Vaccinium uliginosum, was studied in a high arctic heath in North East Greenland during two growing seasons. Films (Mylar, transmitting λ > 320 nm, and Lexan......, respectively. UV radiation decreased the maximal photochemical efficiency (Fv/Fm) and other fast fluorescence transient derived parameters in both species, despite an increased level of leaf flavonoid content. The responses varied in signifi-cance according to species and site. The relation of these effects...

  5. Non-invasive measurements of leaf epidermal transmittance of UV radiation using chlorophyll fluorescence: field and laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.W. [Southwest Texas State Univ.. Dept. of Biology, San Marcos, TX (United States); Searles, P.S.; Ryel, R.J.; Caldwell, M.M. [Utah State Univ., Dept. of Rangeland Resources and the Ecology Center, Logan, UT (United States); Ballare, C.L. [IFEVA, Univ. de Buenos Aires, Dept. de Ecologia, Facultad de Agronomia, Buenos Aires, (Argentina)

    2000-07-01

    Ratios of chlorophyll fluorescence induced by ultraviolet (UV) and bluegreen (BG) radiation [F(UV)/F(BG)] were determined with a Xe-PAM fluorometer to test the utility of this technique as a means of non-intrusively assessing changes in the pigmentation and optical properties of leaves exposed to varying UV exposures under laboratory and field conditions. For plants of Vicia faba and Brassica campestris, grown under controlled-environmental conditions, F(UV-B)/F(BG) was negatively correlated with whole-leaf UV-B-absorbing pigment concentrations. Fluorescence ratios of V.faba were similar to, and positively correlated with (r{sup 2} = 0.77 [UV-B]; 0.85 [UV-A]), direct measurements of epidermal transmittance made with an integrating sphere. Leaves of 2 of 4 cultivars of field-grown Glycine max exposed to near-ambient solar UV-B at a mid-latitude site (Buenos Aires, Argentina, 34 degrees S) showed significantly lower abaxial F(UV-B)/F(BG) values (i.e., lower UV-B epidermal transmittance) than those exposed to attenuated UV-B, but solar UV-B reduction had a minimal effect on F(UV-B)/F(BG) in plants growing at a high-latitude site (Tierra del Fuego, Argentina, 55 degrees S). Similarly, the exotic Taraxacum officinale did not show significant changes in F(UV-B)/F(BG) when exposed to very high supplemental UV-B (biologically effective UV-B = 14-15 kJ m{sup -2} day{sup -1}) in the field in Tierra del Fuego, whereas a native species, Gunnera magellanica, showed significant increases in F(UV-B)/F(BG) relative to those receiving ambient UV-B. These anomalous fluorescence changes were associated with increases in BG-absorbing pigments (anthocyanins), but not UV-B-absorbing pigments. These results indicate that non-invasive estimates of epidermal transmittance of UV radiation using chlorophyll fluorescence can detect changes in pigmentation and leaf optical properties induced by UV-B radiation under both field and laboratory conditions. However, this technique may be of limited

  6. The effect of selenium and UV radiation on leaf traits and biomass production in Triticum aestivum L.

    Science.gov (United States)

    Golob, Aleksandra; Kavčič, Jan; Stibilj, Vekoslava; Gaberščik, Alenka; Vogel-Mikuš, Katarina; Germ, Mateja

    2017-02-01

    UV radiation as an evolutionarily important environmental factor, significantly affects plants traits and alters the effects of other environmental factors. Single and combined effects of ambient UV radiation, its exclusion, and Se foliar treatments on Si concentrations and production of Si phytoliths in wheat (Triticum aestivum L.) cv. 'Reska' were studied. The effects of these treatments on growth parameters of the plants, structural and biochemical traits of the leaves, and interactions of the leaves with light, as Si incrustation is the first barrier to light at the leaf surface were also examined. Under ambient UV radiation and foliar treatment with 10mgL-1 sodium selenate solution, there was a trade-off between the plant investment in primary and secondary metabolism, as the production of UV-absorbing compounds was enhanced while photosynthetic pigment levels were reduced. Independent of Se treatment, ambient UV radiation lowered respiratory potential, Ca concentration, and leaf thickness, and increased Si concentration, Si phytoliths formation, and cuticle thickness. The Se treatment has little effect on plant traits and biomass production but it increased Se concentrations in the plants by >100-fold, independent of UV radiation. In combination with UV radiation Se strengthen the protection of plants against stress by increasing the amount of UV absorbing compounds, light reflectance and transmittance. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. UV-CD12: synchrotron radiation circular dichroism beamline at ANKA.

    Science.gov (United States)

    Bürck, Jochen; Roth, Siegmar; Windisch, Dirk; Wadhwani, Parvesh; Moss, David; Ulrich, Anne S

    2015-05-01

    Synchrotron radiation circular dichroism (SRCD) is a rapidly growing technique for structure analysis of proteins and other chiral biomaterials. UV-CD12 is a high-flux SRCD beamline installed at the ANKA synchrotron, to which it had been transferred after the closure of the SRS Daresbury. The beamline covers an extended vacuum-UV to near-UV spectral range and has been open for users since October 2011. The current end-station allows for temperature-controlled steady-state SRCD spectroscopy, including routine automated thermal scans of microlitre volumes of water-soluble proteins down to 170 nm. It offers an excellent signal-to-noise ratio over the whole accessible spectral range. The technique of oriented circular dichroism (OCD) was recently implemented for determining the membrane alignment of α-helical peptides and proteins in macroscopically oriented lipid bilayers as mimics of cellular membranes. It offers improved spectral quality dichroism artifacts.

  8. UV-B radiation modulates physiology and lipophilic metabolite profile in Olea europaea.

    Science.gov (United States)

    Celeste Dias, Maria; Pinto, Diana C G A; Correia, Carlos; Moutinho-Pereira, José; Oliveira, Helena; Freitas, Helena; Silva, Artur M S; Santos, Conceição

    2018-03-01

    Ultraviolet-B (UV-B) radiation plays an important role in plant photomorphogenesis. Whilst the morpho-functional disorders induced by excessive UV irradiation are well-known, it remains unclear how this irradiation modulates the metabolome, and which metabolic shifts improve plants' tolerance to UV-B. In this study, we use an important Mediterranean crop, Olea europaea, to decipher the impacts of enhanced UV-B radiation on the physiological performance and lipophilic metabolite profile. Young olive plants (cv. 'Galega Vulgar') were exposed for five days to UV-B biologically effective doses of 6.5 kJ m -2  d -1 and 12.4 kJ m -2 d -1 . Cell cycle/ploidy, photosynthesis and oxidative stress, as well as GC-MS metabolites were assessed. Both UV-B treatments impaired net CO 2 assimilation rate, transpiration rate, photosynthetic pigments, and RuBisCO activity, but 12.4 kJ m -2  d -1 also decreased the photochemical quenching (qP) and the effective efficiency of PSII (Φ PSII ). UV-B treatments promoted mono/triperpene pathways, while only 12.4 kJ m -2  d -1 increased fatty acids and alkanes, and decreased geranylgeranyl-diphosphate. The interplay between physiology and metabolomics suggests some innate ability of these plants to tolerate moderate UV-B doses (6.5 kJ m -2  d -1 ). Also their tolerance to higher doses (12.4 kJ m -2  d -1 ) relies on plants' metabolic adjustments, where the accumulation of specific compounds such as long-chain alkanes, palmitic acid, oleic acid and particularly oleamide (which is described for the first time in olive leaves) play an important protective role. This is the first study demonstrating photosynthetic changes and lipophilic metabolite adjustments in olive leaves under moderate and high UV-B doses. Copyright © 2018 Elsevier GmbH. All rights reserved.

  9. Effect of UV radiation on the expulsion of Symbiodinium from the coral Pocillopora damicornis.

    Science.gov (United States)

    Zhou, Jie; Huang, Hui; Beardall, John; Gao, Kunshan

    2017-01-01

    The variation in density of the symbiotic dinoflagellate Symbiodinum in coral is a basic indicator of coral bleaching, i.e. loss of the symbiotic algae or their photosynthetic pigments. However, in the field corals constantly release their symbiotic algae to surrounding water. To explore the underlying mechanism, the rate of expulsion of zooxanthellae from the coral Pocillopora damicornis was studied over a three-day period under ultraviolet radiation (UVR, 280-400nm) stress. The results showed that the algal expulsion rate appeared 10-20% higher under exposure to UV-A (320-395nm) or UV-B (295-320nm), though the differences were not statistically significant. When corals were exposed to UV-A and UV-B radiation, the maximum expulsion of zooxanthellae occurred at noon (10:00-13:00), and this timing was 1h earlier than in the control without UVR. UVR stress led to obvious decreases in the concentrations of chl a and carotenoids in the coral nubbins after a three-day exposure. Therefore, our results suggested that although the UVR effect on algal expulsion rate was a chronic stress and was not significant within a time frame of only three days, the reduction in chl a and carotenoids may potentially enhance the possibility of coral bleaching over a longer period. Copyright © 2016. Published by Elsevier B.V.

  10. Toxic effects of combined effects of anthracene and UV radiation on Brachionus plicatilis

    Science.gov (United States)

    Gao, Ceng; Zhang, Xinxin; Xu, Ningning; Tang, Xuexi

    2017-05-01

    Anthracene is a typical polycyclic aromatic hydrocarbon, with photo activity, can absorb ultraviolet light a series of chemical reactions, aquatic organisms in the ecosystem has a potential light induced toxicity. In this paper, the effects of anthracene and UV radiation on the light-induced toxicity of Brachionus plicatilis were studied. The main methods and experimental results were as follows: (1) The semi-lethal concentration of anthracene in UV light was much lower than that in normal light, The rotifers have significant light-induced acute toxicity. (2) Under UV irradiation, anthracene could induce the increase of ROS and MDA content in B. plicatilis, and the activity of antioxidant enzymes in B. plicatilis significantly changed, Where SOD, GPx activity was induced within 24 hours of the beginning of the experiment. And the content of GPX and CAT was inhibited after 48 hours. Therefore, the anthracite stress induced by UV radiation could more strongly interfere with the ant oxidative metabolism of B. plicatilis, and more seriously cause oxidative damage, significant light-induced toxicity.

  11. The use of clinical broadband UV radiometers for optical radiation hazard measurements.

    Science.gov (United States)

    Foy, Trevelyan

    2011-12-01

    The implementation of the UK Control of Artificial Optical Radiation at Work Regulations 2010 requires the employer to perform a risk assessment of workers' exposure to UV radiation from phototherapy equipment in the hospital environment. The objective of this study was to demonstrate that, where the source spectrum is known, an assessment of exposure to UV sources commonly used in hospitals, including assessment of reflections and transmission through personal protective equipment, may be performed with sufficient reliability by radiometer measurement rather than by complex spectroradiometric measurements. An intercomparison of radiometer and spectroradiometer measurements of exposure to UV sources was carried out. Direct exposure was considered, as well as exposure to reflected or scattered beams and that transmitted through eyewear. Assessment by radiometer of direct exposure and exposure to reflections demonstrated an acceptable measurement error in the context of the inherent uncertainty in the assumptions of the exposure scenario. Assessment of transmitted beams may result in a greater measurement error due to spectral mismatch; however, for typical exposure scenarios the error remained acceptable in comparison with the exposure limit value. The methodology presented reduces the complexity of the measurement of UV hazard levels for common phototherapy equipment.

  12. The reduction of Chlorella vulgaris concentrations through UV-C radiation treatments: A nature-based solution (NBS).

    Science.gov (United States)

    Chen, Erika S; Bridgeman, Thomas B

    2017-07-01

    Algal blooms have become a pressing issue in inland freshwater systems on local and global scales. A plausible approach to reducing algae without the use of chemical/biological agents is through the use of UV-C radiation from lamps potentially powered by in situ solar panels to eliminate algae. Yet, the quantitative scientific base has not been established. Our objective is to conduct a controlled experiment to quantify the effectiveness of UV-C radiation on the reduction of Chlorella vulgaris, a common algal species in the Great Lakes region. A full factorial design of three intensities of UV-C radiation (0, 15, and 30W) and three sources of C. vulgaris was constructed to test the corresponding hypotheses. Empirical models were constructed to predict the reductions. UV-C radiation effectively reduced the algal concentration with clear differences by radiation level and source of algal water. Algal concentration decreased exponentially over time, with distinct decreasing trends among the radiation intensities and the samples. With 15W UV-C radiation, algal concentration of three samples were reduced to 75.3%, 51.5%, and 70.0% of the initial level within an hour, respectively. We also found a clear density-dependent reduction rate by UV radiation. Using this information, more efficient treatment systems could be constructed and implemented for cleaning algae-contaminated water. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. [Medico-biological effects of natural UV-radiation: global consequences of the destruction of the ozone layer].

    Science.gov (United States)

    Strzhizhovskiĭ, A D; D'iakonov, A S; Belousov, V V

    1991-01-01

    The effect of UV-B-radiation of high intensity on terrestrial microorganisms, aqueous ecosystems, and plants is described. The effect of UV-B-radiation on humans and animals is discussed and quantitative evaluation of ozone layer destruction is given. It is indicated that potential changes will grow continuously, producing a significant effect on the biosphere. It is concluded that UV-B-radiation as a stimulating agent should be applied with caution in general biology and medicine and in space biology and medicine.

  14. The effects of different UV-B radiation intensities on morphological and biochemical characteristics in Ocimum basilicum L.

    Science.gov (United States)

    Sakalauskaitė, Jurga; Viskelis, Pranas; Dambrauskienė, Edita; Sakalauskienė, Sandra; Samuolienė, Giedrė; Brazaitytė, Aušra; Duchovskis, Pavelas; Urbonavičienė, Dalia

    2013-04-01

    The effects of short-term ultraviolet B (UV-B) irradiation on sweet basil (Ocimum basilicum L. cv. Cinnamon) plants at the 3-4 leaf pair and flowering stages were examined in controlled environment growth chambers. Plants were exposed to 0 (reference), 2 and 4 kJ UV-B m(-2) day(-1) over 7 days. Exposure of basil plants to supplementary UV-B light resulted in increased assimilating leaf area, fresh biomass and dry biomass. Stimulation of physiological functions in young basil plants under either applied UV-B dose resulted in increased total chlorophyll content but no marked variation in carotenoid content. At the flowering stage the chlorophyll and carotenoid contents of basil were affected by supplementary UV-B radiation, decreasing with enhanced UV-B exposure. Both total antioxidant activity (2,2-diphenyl-1-picrylhydrazyl free radical assay) and total phenolic compound content were increased by UV-B light supplementation. Young and mature basil plants differed in their ascorbic acid content, which was dependent on UV-B dose and plant age. UV-B radiation resulted in decreased nitrate content in young basil plants (3-4 leaf pair stage). These results indicate that the application of short-exposure UV-B radiation beneficially influenced both growth parameters and biochemical constituents in young and mature basil plants. © 2012 Society of Chemical Industry.

  15. Investigation of 207 nm UV radiation for degradation of organic dye ...

    African Journals Online (AJOL)

    The photo-degradation of organic dye C.I. Acid Red 213 (AR-213) was achieved by 207 nm UV radiation emitted from a planar KrBr* excimer lamp without addition of oxidants at varying initial pH values. Precipitates were found to be generated when the irradiated solution of initial acid pH was adjusted to alkaline pH and ...

  16. Neural Network on Photodegradation of Octylphenol using Natural and Artificial UV Radiation

    OpenAIRE

    Jäntschi, Lorentz; Letiţia OPREAN; Dana - Melania POPA

    2011-01-01

    The present paper comes up with an experimental design meant to point out the factors interferingin octylphenol’s degradation in surface waters under solar radiation, underlining each factor’sinfluence on the process observable (concentration of p-octylphenol). Multiple linear regressionanalysis and artificial neural network (Multi-Layer Perceptron type) were applied in order to obtaina mathematical model capable to explain the action of UV-light upon synthetic solutions of OP inultra-pure wa...

  17. Variability in tolerance to UV-B radiation among Beauveria spp. isolates

    OpenAIRE

    Fernandes, Éverton K. K.; Rangel, Drauzio E. N.; Moraes, Âurea M. L.; Bittencourt, Vânia R. E. P.; Roberts, Donald W.

    2007-01-01

    Solar radiation, particularly the UV-B component, negatively affects survival of entomopathogenic fungi in the field. In an effort to identify Beauveria spp. isolates with promise for use in biological control settings with high insolation, we examined 53 Beauveria bassiana isolates, 7 isolates of 4 other Beauveria spp. and Engyodontium albus (=Beauveria alba). The origins of these fungi varied widely as to host/substrate and country, but approximately 30% of these isolates were B. bassiana f...

  18. Fluence Rate in UV Photoreactor for Disinfection of Water: Isotropically Radiating Cylinder

    Directory of Open Access Journals (Sweden)

    Roman Ilinsky

    2014-01-01

    Full Text Available The calculation of fluence rate in the photochemical reactor using ultraviolet (UV radiation for disinfection of water for the case, when a cylinder of infinite length is used as a light source, has been considered. Such a cylinder is filled with an isotropically radiating medium. The dependence of the fluent rate on the diameter of the radiating cylinder has been analytically analyzed. The limiting case when the diameter of the radiating cylinder tends to zero has been considered and the notion of “effective interval” has been introduced. Based on this notion, the comparison of fluence rates for the cylinders of finite and infinite lengths has been performed. In the calculations of fluence rate, it is advisable to use the Chebyshev method for the operations of numerical integration.

  19. Rapid maize leaf and immature ear responses to UV-B radiation

    Directory of Open Access Journals (Sweden)

    Paula eCasati

    2011-07-01

    Full Text Available Because of their sessile lifestyle, plants have evolved adaptations to environmental factors, including UV-B present in solar radiation. To gain a better understanding of the initial events in UV-B acclimation, we have analyzed a 10min to 1h time course of transcriptome responses in irradiated and shielded leaves, and immature maize ears to unravel the systemic physiological and developmental responses in exposed and shielded organs. After 10 min of UV-B exposure, 262 transcripts are changed by at least 2-fold in irradiated leaves, and this number doubles after 1h. Indicative of the rapid modulation of transcription, 130 transcripts are only changed after 10 min. This is true not only in irradiated leaves, but also in shielded tissues. After 10 min of exposure, the overlap in transcriptome changes in irradiated and shielded organs is significant; however, after 30 min of UV-B, there are only 2 transcripts showing similar UV-B regulation between the three organs; 35 are similarly regulated in both IL and SL. Therefore, at longer irradiation times, there is more specificity of responses, and these are organ-specific. We suggest that early signaling in different tissues may be elicited by common signaling pathways, while at longer exposure times responses become more specific. To identify metabolites as possible signaling molecules, we looked for compounds that increased within 5-90 min in both irradiated and shielded leaves, to explain the kinetics of profound transcript changes within 1h. We found that myoinositol is one such candidate metabolite; and we also demonstrate that if 0.1mM myoinositol is applied to leaves of greenhouse maize, some metabolites that are changed by UV-B are also changed similarly by the chemical treatment. Therefore, this metabolite can partially mimic UV irradiation.

  20. Improving radiation data quality of USDA UV-B monitoring and research program and evaluating UV decomposition in DayCent and its ecological impacts

    Science.gov (United States)

    Chen, Maosi

    Solar radiation impacts many aspects of the Earth's atmosphere and biosphere. The total solar radiation impacts the atmospheric temperature profile and the Earth's surface radiative energy budget. The solar visible (VIS) radiation is the energy source of photosynthesis. The solar ultraviolet (UV) radiation impacts plant's physiology, microbial activities, and human and animal health. Recent studies found that solar UV significantly shifts the mass loss and nitrogen patterns of plant litter decomposition in semi-arid and arid ecosystems. The potential mechanisms include the production of labile materials from direct and indirect photolysis of complex organic matters, the facilitation of microbial decomposition with more labile materials, and the UV inhibition of microbes' population. However, the mechanisms behind UV decomposition and its ecological impacts are still uncertain. Accurate and reliable ground solar radiation measurements help us better retrieve the atmosphere composition, validate satellite radiation products, and simulate ecosystem processes. Incorporating the UV decomposition into the DayCent biogeochemical model helps to better understand long-term ecological impacts. Improving the accuracy of UV irradiance data is the goal of the first part of this research and examining the importance of UV radiation in the biogeochemical model DayCent is the goal of the second part of the work. Thus, although the dissertation is separated into two parts, accurate UV irradiance measurement links them in what follows. In part one of this work the accuracy and reliability of the current operational calibration method for the (UV-) Multi-Filter Rotating Shadowband Radiometer (MFRSR), which is used by the U.S. Department of Agriculture UV-B Monitoring and Research Program (UVMRP), is improved. The UVMRP has monitored solar radiation in the 14 narrowband UV and VIS spectral channels at 37 sites across U.S. since 1992. The improvements in the quality of the data result

  1. Hornet peak flight activity is correlated with solar UV radiation: a multi-annual survey.

    Science.gov (United States)

    Ishay, Jacob S; Pertsis, Vitaly

    2002-01-01

    This study deals with the effect which solar irradiation of short wavelength, particularly ultraviolet (UV), exerts on the activities of hornets. The findings are based on multi-annual observations carried out during the years 1985, 1989 and 1998 on hornet nests in the field. At the peak of UV radiation, which occurs at noon, hornet activity is greater by 1-2 orders of magnitude than that during the morning or evening hours. The main visible hornet activity appears to be the removal of soil particles from the nest so as to enlarge its volume, enable the building of additional combs and also increase the size of existing combs. Hornet flight during peak insolation hours is characterized by its briefness (5-20 seconds only) and brevity (to distances of 5-10 meters only) as compared to flights at other hours of the day. These prolonged, multi-annual observations lead to the conclusion that hornets are capable of converting the energy of UV radiation into a form amenable to metabolic usage. In this respect the hornet cuticle behaves as a thermophotovoltaic device, i.e., a semiconductor diode that converts photons radiating from the sunlight into electrical energy.

  2. Crosslink the Novel Group of Polymeric Binders BioCo by the UV-radiation

    Directory of Open Access Journals (Sweden)

    Grabowska B.

    2016-06-01

    Full Text Available The spectroscopic FT-IR and FT-Raman methods allowed to identify the cross-linking process of the aqueous composition of poly(acrylic acid/sodium salt of carboxymethyl starch (PAA/CMS-Na applied as a binder for moulding sands (as a novel group binders BioCo. The cross-linking was performed by physical agent, applying the UV-radiation. The results of structural studies (IR, Raman confirm the overlapping of the process of cross-linking polymer composition PAA/CMS-Na in UV radiation. Taking into account the ingredients and structure of the polymeric composition can also refer to a curing process in a binder - mineral matrix mixture. In the system of binder-mineral matrix under the influence of ultraviolet radiation is also observed effect of binding. However, the bonding process does not occur in the entire volume of the investigated system, but only on the surface, which gives some possibilities for application in the use of UV curing surface of cores, and also to cure sand moulds in 3D printing technology.

  3. Response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings exposed to UV-B.

    Science.gov (United States)

    Chen, Yi-Ping

    2009-07-01

    To determine the response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings, Isatis indigotica seedlings were subjected to UV-B radiation (10.08 kJ m(-2)) for 8 h day(-1) for 8 days (PAR, 220 micromol m(-2) s(-1)) and then exposed to He-Ne laser radiation (633 nm; 5.23 mW mm(-2); beam diameter: 1.5 mm) for 5 min each day without ambient light radiation. Changes in free radical elimination systems were measured, the results indicate that: (1) UV-B radiation enhanced the concentration of Malondialdahyde (MDA) and decreased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in seedlings compared with the control. The concentration of MDA was decreased and the activities of SOD, CAT and POD were increased when seedlings were subjected to elevated UV-B damage followed by laser; (2) the concentration of UV absorbing compounds and proline were increased progressively with UV-B irradiation, laser irradiation and He-Ne laser irradiation plus UV-B irradiation compared with the control. These results suggest that laser radiation has an active function in repairing UV-B-induced lesions in seedlings.

  4. Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen.

    Science.gov (United States)

    Bruhn, D; Mikkelsen, T N; Rolsted, M M M; Egsgaard, H; Ambus, P

    2014-03-01

    The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4 ) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we investigated the potential of the leaf surface wax itself as a source of UV radiation-induced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation to this, we demonstrated that the UV radiation-induced CH4 emission is independent of leaf area index above unity. Further, we observed that the presence of O2 in the atmosphere was necessary for achieving the highest rates of CH4 emission. Methane formation from leaf surface wax is supposedly a two-step process initiated by a photolytic rearrangement reaction of the major component followed by an α-cleavage of the generated ketone. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

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

    Science.gov (United States)

    Rozema, J; Björn, L O; Bornman, J F; Gaberscik, A; Häder, D-P; Trost, T; Germ, M; Klisch, M; Gröniger, A; Sinha, R P; Lebert, M; He, Y-Y; Buffoni-Hall, R; de Bakker, N V J; van de Staaij, J; Meijkamp, B B

    2002-02-01

    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 amphibious macrophytes. Lichens were also included in the study. We were interested in the following key aspects: (a) does the water column function effectively as an 'external UV-B filter'?; (b) do aquatic plants need less 'internal UV-B screening' than terrestrial plants?; (c) what role does UV screening play in protecting the various plant groups from UV-B damage, such as the formation of thymine dimers?; and (d) since early land 'plants' (such as the predecessors of present-day cyanobacteria, lichens and mosses) experienced higher UV-B fluxes than higher plants, which evolved later, are primitive aquatic and land organisms (cyanobacteria, algae, lichens, mosses) better adapted to present-day levels of UV-B than higher plants? Furthermore, polychromatic action spectra for the induction of UV screening pigments of aquatic organisms have been determined. This is relevant for translating 'physical' radiation measurements of solar UV-B into 'biological' and 'ecological' effects. From the action spectra, radiation amplification factors (RAFs) have been calculated. These action spectra allow us to determine any mitigating or antagonistic effects in the ecosystems and therefore qualify the damage prediction for the ecosystems under study. We summarize and discuss the main results based on three years of research of four European research groups. The central theme of the work was the investigation of the effectiveness of the various screening compounds from the different species studied in order to gain some perspective of the evolutionary adaptations from lower to higher plant forms. The induction of mycosporine-like amino acids (MAAs) was studied in the marine dinoflagellate

  6. Development of Ultraviolet (UV) Radiation Protective Fabric Using Combined Electrospinning and Electrospraying Technique

    Science.gov (United States)

    Sinha, Mukesh Kumar; Das, B. R.; Kumar, Kamal; Kishore, Brij; Prasad, N. Eswara

    2017-06-01

    The article reports a novel technique for functionization of nanoweb to develop ultraviolet (UV) radiation protective fabric. UV radiation protection effect is produced by combination of electrospinning and electrospraying technique. A nanofibrous web of polyvinylidene difluoride (PVDF) coated on polypropylene nonwoven fabric is produced by latest nanospider technology. Subsequently, web is functionalized by titanium dioxide (TiO2). The developed web is characterized for evaluation of surface morphology and other functional properties; mechanical, chemical, crystalline and thermal. An optimal (judicious) nanofibre spinning condition is achieved and established. The produced web is uniformly coated by defect free functional nanofibres in a continuous form of useable textile structural membrane for ultraviolet (UV) protective clothing. This research initiative succeeds in preparation and optimization of various nanowebs for UV protection. Field Emission Scanning Electron Microscope (FESEM) result reveals that PVDF webs photo-degradative behavior is non-accelerated, as compared to normal polymeric grade fibres. Functionalization with TiO2 has enhanced the photo-stability of webs. The ultraviolet protection factor of functionalized and non-functionalized nanowebs empirically evaluated to be 65 and 24 respectively. The developed coated layer could be exploited for developing various defence, para-military and civilian UV protective light weight clothing (tent, covers and shelter segments, combat suit, snow bound camouflaging nets). This research therefore, is conducted in an attempt to develop a scientific understanding of PVDF fibre coated webs for photo-degradation and applications for defence protective textiles. This technological research in laboratory scale could be translated into bulk productionization.

  7. The effects of UV radiation during the vegetative period on antioxidant compounds and postharvest quality of broccoli (Brassica oleracea L.).

    Science.gov (United States)

    Topcu, Yasin; Dogan, Adem; Kasimoglu, Zehra; Sahin-Nadeem, Hilal; Polat, Ersin; Erkan, Mustafa

    2015-08-01

    In this study, the effects of supplementary UV radiation during the vegetative period on antioxidant compounds, antioxidant activity and postharvest quality of broccoli heads during long term storage was studied. The broccolis were grown under three different doses of supplementary UV radiation (2.2, 8.8 and 16.4 kJ/m(2)/day) in a soilless system in a glasshouse. Harvested broccoli heads were stored at 0 °C in modified atmosphere packaging for 60 days. The supplementary UV radiation (280-315 nm) during the vegetative period significantly decreased total carotenoid, the chlorophyll a and chlorophyll b content but increased the ascorbic acid, total phenolic and flavonoid contents of broccolis. All supplementary UV treatments slightly reduced the antioxidant activity of the broccolis, however, no remarkable change was observed between 2.2 and 8.8 kJ/m(2) radiation levels. The sinigrin and glucotropaeolin contents of the broccolis were substantially increased by UV treatments. The prolonged storage period resulted in decreased ascorbic acid, total phenolic and flavonoid contents, as well as antioxidant activity. Discoloration of the heads, due to decreased chlorophyll and carotenoid contents, was also observed with prolonged storage duration. Glucosinolates levels showed an increasing tendency till the 45th day of storage, and then their levels started to decline. The weight loss of broccoli heads during storage progressively increased with storage time in all treatments. Total soluble solids, solids content and titratable acidity decreased continuously during storage. Titratable acidity was not affected by UV radiation doses during the storage time whereas soluble solids and solids content (dry matter) were significantly affected by UV doses. Supplementary UV radiation increased the lightness (L*) and chroma (C*) values of the broccoli heads. Pre-harvest UV radiation during vegetative period seems to be a promising tool for increasing the beneficial health components

  8. Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: a review

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Beerendonk, E.F.; Medema, Gerriet Jan

    2006-01-01

    UV disinfection technology is of growing interest in the water industry since it was demonstrated that UV radiation is very effective against (oo)cysts of Cryptosporidium and Giardia, two pathogenic micro-organisms of major importance for the safety of drinking water. Quantitative Microbial Risk

  9. RESPONSE OF OXIDATIVE STRESS DEFENSE SYSTEMS IN RICE (ORYZA SATIVA) LEAVES WITH SUPPLEMENTAL UV-B RADIATION

    Science.gov (United States)

    The impact of elevated ultraviolet-B radiation (UV-B, 280-320 nm) on membrane systems and lipid peroxidation, and possible involvement of active oxygen radicals was investigated in leaves of two UV-B susceptible rice cultivars (Oryza sativa L. cvs IR74 and Dular). Rice seedlings ...

  10. Mediated modeling of the impacts of enhanced UV-B radiation on ecosystem services.

    Science.gov (United States)

    van den Belt, Marjan; Bianciotto, Oscar A; Costanza, Robert; Demers, Serge; Diaz, Susana; Ferreyra, Gustavo A; Koch, Evamaria W; Momo, Fernando R; Vernet, Maria

    2006-01-01

    This article describes the use of group model building to facilitate interaction with stakeholders, synthesize research results and assist in the development of hypotheses about climate change at the global level in relation to UV-B radiation and ecosystem service valuation. The objective was to provide a platform for integration of the various research components within a multidisciplinary research project as a basis for interaction with stakeholders with backgrounds in areas other than science. An integrated summary of the scientific findings, along with stakeholder input, was intended to produce a bridge between science and policymaking. We used a mediated modeling approach that was implemented as a pilot project in Ushuaia, Argentina. The investigation was divided into two participatory workshops: data gathering and model evaluation. Scientists and the local stakeholders supported the valuation of ecosystem services as a useful common denominator for integrating the various scientific results. The concept of economic impacts in aquatic and marsh systems was represented by values for ecosystem services altered by UV-B radiation. In addition, direct local socioeconomic impacts of enhanced UV-B radiation were modeled, using data from Ushuaia. We worked with 5 global latitudinal regions, focusing on net primary production and biomass for the marine system and on 3 plant species for the marsh system. Ecosystem service values were calculated for both sectors. The synthesis model reflects the conclusions from the literature and from experimental research at the global level. UV-B is not a significant stress for the marshes, relative to the potential impact of increases in the sea level. Enhanced UV-B favors microbial dynamics in marine systems that could cause a significant shift from primary producers to bacteria at the community level. In addition, synergetic effects of UV-B and certain pollutants potentiate the shift to heterotrophs. This may impact the oceanic

  11. Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data

    Directory of Open Access Journals (Sweden)

    U. Feister

    2008-06-01

    Full Text Available Artificial Neural Networks (ANN are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Special emphasis will be given to the discussion of small-scale characteristics of input data to the ANN model.

    Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980/1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

  12. Wettability modification of human tooth surface by water and UV and electron-beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tiznado-Orozco, Gaby E., E-mail: gab0409@gmail.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Unidad Académica de Odontología, Universidad Autónoma de Nayarit, Edificio E7, Ciudad de la Cultura “Amado Nervo”, C.P. 63190 Tepic, Nayarit (Mexico); Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Instituto de Física, UNAM, Circuito de la Investigación s/n, Ciudad Universitaria, 04510 Coyoacan, México, D.F. (Mexico); Elefterie, Florina, E-mail: elefterie_florina@yahoo.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Beyens, Christophe, E-mail: christophe.beyens@ed.univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Maschke, Ulrich, E-mail: Ulrich.Maschke@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Brès, Etienne F., E-mail: etienne.bres@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France)

    2015-12-01

    The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. - Highlights: • Human tooth surface wettability changes in dry/wet and UV/EB radiation conditions. • More variability in contact angle is observed on enamel than on dentin surfaces. • Water by itself increases the hydrophobicity of the human tooth surface. • UV irradiation reduces momentarily the human tooth surface hydrophobicity. • EB irradiation increases and maintains the hydrophobicity for a long time.

  13. Evaluation of promotional gadgets integrating UV patches for public awareness on ultraviolet radiation.

    Science.gov (United States)

    Pettazzi, A

    2007-10-01

    Ultraviolet (UV) patches are included in promotional gadgets advertising the most diverse products. These items are freely distributed to the public as a suggestive instrument of information. This study intends to evaluate the accuracy of these gadgets in providing information about UV exposure as defined by the INTERSUN programme. The design of five gadgets, the instructions and advices included, were analysed. The response of the patches has been compared with UV index measurements and related to the guidelines provided by the INTERSUN programme. The objectivity of the response and its interpretation have also been evaluated, comparing the readings by different operators. The gadgets provide non-standard and ambiguous information, they lack rigorous recommendations on solar protection and have a poor design. Although the patches underestimated UV radiation only a few times, overestimation occurred frequently. Observations pointed out the difficulty in establishing objective readings. The analysis highlighted the inadequacy of these items. This fact is serious because the gadgets are freely distributed to the public and some of the advertisers are well-known companies. Instead of using these gadgets, the public should pay attention to the information and advice provided by health and weather services.

  14. UV Radiation Detection Using Optical Sensor Based on Eu3+ Doped PMMA

    Directory of Open Access Journals (Sweden)

    Miluski Piotr

    2016-12-01

    Full Text Available Progress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl methacrylate (PMMA matrix doped by europium was used for testing the optical sensor (optrode construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.

  15. Solar UV-B radiation modulates chemical defenses against Anticarsia gemmatalis larvae in leaves of field-grown soybean.

    Science.gov (United States)

    Dillon, Francisco M; Chludil, Hugo D; Zavala, Jorge A

    2017-09-01

    Although it is well known that solar ultraviolet B (UV-B) radiation enhances plant defenses, there is less knowledge about traits that define insect resistance in field-grown soybean. Here we study the effects of solar UV-B radiation on: a) the induction of phenolic compounds and trypsin proteinase inhibitors (TPI) in soybean undamaged leaves or damaged by Anticarsia gemmatalis neonates during six days, and b) the survival and mass gain of A. gemmatalis larvae that fed on soybean foliage. Two soybean cultivars (cv.), Charata and Williams, were grown under plastic with different transmittance to solar UV-B radiation, which generated two treatments: ambient UV-B (UVB+) and reduced UV-B (UVB-) radiation. Solar UV-B radiation decreased survivorship by 30% and mass gain by 45% of larvae that fed on cv. Charata, but no effect was found in those larvae that fed on cv. Williams. TPI activity and malonyl genistin were induced by A. gemmatalis damage in both cultivars, but solar UV-B radiation and damage only synergistically increased the induction of these compounds in cv. Williams. Although TPI activity and genistein derivatives were induced by herbivory, these results did not explain the differences found in survivorship and mass gain of larvae that fed on cv. Charata. However, we found a positive association between lower larval performance and the presence of two quercetin triglycosides and a kaempferol triglycoside in foliage of cv. Charata, which were identified by HPLC-DAD/MS 2 . We conclude that exclusion of solar UV-B radiation reduce resistance to A. gemmatalis, due to a reduction in flavonol concentration in a cultivar that has low levels of genistein derivatives like cv. Charata. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Enhanced resistance to UV-B radiation in Anabaena sp. PCC 7120 (Cyanophyceae) by repeated exposure.

    Science.gov (United States)

    Qin, Hongjie; Li, Dunhai

    2014-07-01

    In natural habitats, organisms especially phytoplankton are not always continuously subjected to ultraviolet-B radiation (UVBR). By simulation of the natural situation, the N2-fixing cyanobacterium Anabaena sp. PCC 7120 was subjected to UV-B exposure and recovery cycles. A series of morphological and physiological changes were observed in Anabaena sp. PCC 7120 under repeated UVBR when compared with controls. Such as the breakage of filaments, intervals between heterocysts, heterocyst frequency, total carbohydrate, and carotenoids were increased, while the nitrogenase activity and photosynthetic activity were inhibited by repeated UVBR; however, these activities could recover when UV-B stress was removed. Unexpectedly, the over-compensatory growth was observed at the end of the second round of exposure and recovery cycle. Our results showed that discontinuous UVBR could increase the growth rate and the tolerance as well as repair capacity of Anabaena sp. PCC 7120. These results indicate that moderate UVBR may increase the growth of cyanobacteria in natural habitats.

  17. Sunlight suppressing rejection of 280- to 320-nm UV-radiation-induced skin tumors in mice

    Energy Technology Data Exchange (ETDEWEB)

    Morison, W.L.; Kelley, S.P.

    1985-02-01

    Repeated exposure of female C3H/HeNCR- mice to sunlight prevented the normal immunologic rejection of a UV-induced tumor. This systemic immunologic alteration was transferred to syngeneic lethally X-irradiated animals with lymphoid cells from mice exposed to sunlight. The lymphoid cells also were able to suppress the capacity of lymphoid cells from normal animals to reject a UV-induced tumor. The 295- to 320-nm wave band appeared to be responsible for this immunosuppressive effect of sunlight because suppression was prevented by filtration of the radiation through Mylar and by application of a sunscreen containing para-aminobenzoic acid. These observations may have importance in understanding the pathogenesis of sunlight-induced skin cancer in humans.

  18. Controlling adverse and beneficial effects of solar UV radiation by wearing suitable clothes - spectral transmission of different kinds of fabrics.

    Science.gov (United States)

    Sobolewski, Piotr S; Krzyścin, Janusz W; Jarosławski, Janusz; Wink, Jakub; Lesiak, Aleksandra; Narbutt, Joanna

    2014-11-01

    Humans should avoid prolonged exposure to the Sun during the warm subperiod of the year with naturally high solar UV level. One of the known recommendations to avoid excessive UV radiation is wearing clothes with UV protection additives. However there is an important question: how do we get an adequate solar UV radiation, which maintains a healthy status of vitamin D, without facing overexposure risks? It is found that some kind of 100% cotton knitted fabric, used in the production of normal daily clothing, has ∼15% transmittance of solar UV. Model studies show that a garment made of this fabric allows larger synthesis of vitamin D3 in human body without the erythema risks (skin redness). Thus the adequate level of vitamin D could be attained safely by a person exposing only small part of the body (face, palms) during the period (May-August) of the year. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. [Changes in chemistry component structure and microstructure characterization of acetylated wood before and after UV radiation].

    Science.gov (United States)

    Fu, Zhan; Liu, Yi; Xing, Fang-Ru; Guo, Hong-Wu

    2014-11-01

    The poplar powder was acetylated with different duration as sample, processed ray radiation by using ultraviolet test box, contrasting the influences to lightfastness of wood with different acetylation degree, analyzing changing rules of characteristic peaks' intensity which belonged to the chemistry components of samples based on FTIR spectra, and the relationship between duration of acetylation and changes of chemistry components was established, The results showed that: Before UV radiation, the characteristic peaks' intensity of acetylated poplar powder at 1 739 cm(-1) which belonged to C = O in saturated esters compounds and 1 385 cm(-1) which belonged to C-H in acetate were higher than untreated ones', the poplar powder with 40 min's acetylation has the highest characteristic peaks' intensity, highest weight gain rate, remarkable acetylation effect; After UV radiation, characteristic peaks' intensity of Benzene at 1 504 cm(-1) which belonged to lignin of poplar powder was obviously higher than untreated ones', and characteristic peaks' intensity of poplar powder with 40 min's acetylation was the highest, this showed that acetylation could effectively reduce the light degradation of wood chemistry components, in order to improve the lightfastness, especially the poplar powder with 40 min's acetylation; SEM photos showed that, the fibrous surface of acetylated poplar powder was more smooth and had more narrow particle size than untreated ones', so acetylation can effectively improve the stability of wood.

  20. Rpb1 sumoylation in response to UV radiation or transcriptional impairment in yeast.

    Directory of Open Access Journals (Sweden)

    Xuefeng Chen

    Full Text Available Covalent modifications of proteins by ubiquitin and the Small Ubiquitin-like MOdifier (SUMO have been revealed to be involved in a plethora of cellular processes, including transcription, DNA repair and DNA damage responses. It has been well known that in response to DNA damage that blocks transcription elongation, Rpb1, the largest subunit of RNA polymerase II (Pol II, is ubiquitylated and subsequently degraded in mammalian and yeast cells. However, it is still an enigma regarding how Pol II responds to damaged DNA and conveys signal(s for DNA damage-related cellular processes. We found that Rpb1 is also sumoylated in yeast cells upon UV radiation or impairment of transcription elongation, and this modification is independent of DNA damage checkpoint activation. Ubc9, an E2 SUMO conjugase, and Siz1, an E3 SUMO ligase, play important roles in Rpb1 sumoylation. K1487, which is located in the acidic linker region between the C-terminal domain and the globular domain of Rpb1, is the major sumoylation site. Rpb1 sumoylation is not affected by its ubiquitylation, and vice versa, indicating that the two processes do not crosstalk. Abolishment of Rpb1 sumoylation at K1487 does not affect transcription elongation or transcription coupled repair (TCR of UV-induced DNA damage. However, deficiency in TCR enhances UV-induced Rpb1 sumoylation, presumably due to the persistence of transcription-blocking DNA lesions in the transcribed strand of a gene. Remarkably, abolishment of Rpb1 sumoylation at K1487 causes enhanced and prolonged UV-induced phosphorylation of Rad53, especially in TCR-deficient cells, suggesting that the sumoylation plays a role in restraining the DNA damage checkpoint response caused by transcription-blocking lesions. Our results demonstrate a novel covalent modification of Rpb1 in response to UV induced DNA damage or transcriptional impairment, and unravel an important link between the modification and the DNA damage checkpoint response.

  1. DNA damage and photosynthesis in Antarctic and Arctic Sanionia uncinata (Hedw.) Loeske under ambient and enhanced levels of UV-B radiation

    NARCIS (Netherlands)

    Lud, D; Moerdijk, T.C W; van de Poll, W.H.; Buma, A.G.J.; Huiskes, A.H L

    2002-01-01

    The response of the bipolar moss Sanionia uncinata (Hedw.) Loeske to ambient and enhanced UV-B radiation was investigated at an Antarctic (Leonie Island, 67degrees35' S, 68degrees20' W) and an Arctic (Ny-Alesund, 78degrees55' N, 11degrees56' E) site, which differed in ambient UV-B radiation (UV-BR:

  2. Effects of lanthanum(III) on nitrogen metabolism of soybean seedlings under elevated UV-B radiation.

    Science.gov (United States)

    Cao, Rui; Huang, Xiao-hua; Zhou, Qing; Cheng, Xiao-ying

    2007-01-01

    The hydroponic culture experiments of soybean bean seedlings were conducted to investigate the effect of lanthanum (La) on nitrogen metabolism under two different levels of elevated UV-B radiation (UV-B, 280-320 nm). The whole process of nitrogen metabolism involves uptake and transport of nitrate, nitrate assimilation, ammonium assimilation, amino acid biosynthesis, and protein synthesis. Compared with the control, UV-B radiation with the intensity of low level 0.15 W/m2 and high level 0.45 W/m2 significantly affected the whole nitrogen metabolism in soybean seedlings (p nitrogen-metabolism-related enzymes, such as: nitrate reductase (NR) to the nitrate reduction, glutamine systhetase (GS) and glutamine synthase (GOGAT) to the ammonia assimilation, while it increased the content of free amino acids and decreased that of soluble protein as well. The damage effect of high level of UV-B radiation on nitrogen metabolism was greater than that of low level. And UV-B radiation promoted the activity of the anti-adversity enzyme glutamate dehydrogenase (GDH), which reduced the toxicity of excess ammonia in plant. After pretreatment with the optimum concentration of La (20 mg/L), La could increase the activity of NR, GS, GOGAT, and GDH, and ammonia assimilation, but decrease nitrate and ammonia accumulation. In conclusion, La could relieve the damage effect of UV-B radiation on plant by regulating nitrogen metabolism process, and its alleviating effect under low level was better than that under the high one.

  3. 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.

  4. Enhanced UV-B radiation alleviates the adverse effects of summer drought in two Mediterranean pines under field conditions

    Energy Technology Data Exchange (ETDEWEB)

    Petropoulou, Y.; Kyparissis, A.; Nikolopoulos, D.; Manetas, Y. [Univ. of Patras, Lab. of Pland Physiology, Dept. of Biology, Patras (Greece)

    1995-06-01

    The effects of enhanced UV-B (290-320 nm) radiation on two native Mediterranean pines (Pinus pinea L., Pinus halepensis Mill.) were recorded during a one-year field study. Plants received ambient or ambient plus supplemental UV-B radiation (simulating a 15% stratospheric ozone depletion over Patras, Greece, 38.3 deg. N, 29.1 deg. E) and only natural precipitation, i.e. they were simultaneously exposed to other natural stresses, particularly water stress during summer. Supplemental UV-B irradiation started in early February, 1993 and up to late June, no effects were observed on growth and photochemical efficiency of photosystem II, as measured by chlorophyll fluorescence induction. Water stress during the summer was manifested in the control plants as a decline in the ratio of variable to maximum fluorescence (F{sub v}/F{sub m}), the apparent photon yield for oxygen evolution ({Phi}{sub i}) and the photosynthetic capacity at 5% CO{sub 2} (P{sub m}). In addition, a partial needle loss was evident. Under supplemental UV-B radiation. However, the decreases in F{sub v}/F{sub m}, {Phi}{sub i}, and P{sub m}, as well as needle losses were significantly less. Soon after the first heavy autumn rains, photosynthetic parameters in both control and UV-B treated plants recovered to similar values, but the transient summer superiority of UV-B irradiated plants resulted in a significant increase in their dry weight measured at plant harvest, during late January, 1994. Plant height, UV-B absorbing compounds, photosynthetic pigments and relative water content measured at late spring, late summer and at plant harvest, were not significantly affected by supplemental UV-B radiation. The results indicate that enhanced UV-B radiation may be beneficial for Mediterranean pines through a partial alleviation of the adverse effects of summer drought. (au) (36 refs.)

  5. Effect of UV-B radiation on UV absorbing compounds and pigments of moss and lichen of Schirmacher oasis region, East Antarctica.

    Science.gov (United States)

    Singh, J; Gautam, S; Bhushan Pant, A

    2012-12-22

    The survival of Antarctic flora under ozone depletion depends on their ability to acclimate against increasing UV—B radiation by employing photo protective mechanisms either by avoiding or repairing UV—B damage. A fifteen days experiment was designed to study moss (Bryum argenteum) and lichen (Umbilicaria aprina) under natural UV—B exposure and under UV filter frames at the Maitri region of Schirmacher oasis, East Antarctica. Changes in UV absorbing compounds, phenolics, carotenoids and chlorophyll content were studied for continuous fifteen days and significant changes were observed in the UV exposed plants of B. argenteum and U. aprina. The change in the UV absorbing compounds was more significant in B. argenteum (P<0.0001) than U. aprina (P<0.0002). The change in phenolic contents and total carotenoid content was significant (P<0.0001) in both B. argenteum and lichen U. aprina indicating that the increase in UV absorbing compounds, phenolic contents and total carotenoid content act as a protective mechanism against the deleterious effect of UV—B radiations.

  6. A high-brightness repetitively pulsed UV radiation source using a linearly stabilized surface discharge

    Science.gov (United States)

    Bugrimov, S. N.; Kamrukov, A. S.; Kashnikov, G. N.; Kozlov, N. P.; Ovchinnikov, P. A.

    1986-01-01

    A method is proposed for initiating spark plasma discharges on a dielectric surface in the form of strictly rectilinear plasma channels. The method can be implemented using relatively modest (less than 25 kV) working and ignition voltages and does not require any 'hard' electrotechnical loops. Experiments were carried out in order to study the formation dynamics, energy, and spectral brightness characteristics of linearly stabilized surface discharges having linearly stabilized spark channel and the results are discussed. High-speed photographs of the discharges are presented and the spectrum of radiation from the discharges is illustrated in graphic form. It is shown that linearly stabilized discharges can be used to obtain high-power repetitively pulsed sources of CW ultraviolet radiation in the UV region having a brightness temperature of at least 40 K.

  7. UV/X-Ray Diffraction Radiation for non-intercepting Micron-Scale Beam Size Measurement

    CERN Document Server

    -; Lefevre, T; Karataev, P; Billing, M

    2012-01-01

    Diffraction radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. Therefore DR can be used to develop non-invasive diagnostic tools. The aim of this project is to measure the transverse (vertical) beam size using incoherent DR. To achieve the micron-scale resolution required by CLIC, DR in UV and X-ray spectral-range must be investigated. During the next few years, experimental validation of such a scheme will be conducted on the CesrTA at Cornell University, USA. Here we present the current status of the experiment preparation.

  8. Effects of a tryptophan supplemented diet and U.V. radiation on the rat lens.

    Science.gov (United States)

    Mathur, R L; Sahai, P

    1990-01-01

    Rats maintained on a tryptophan supplemented diet and exposed to U.V. radiation showed decreased concentration of ascorbic acid in serum. In the lens, a small increase in the urea-mercaptoethanol soluble fraction was observed suggesting some oxidation of P-SH groups. The decreased concentrations of lens glutathione and ascorbic acid were accompanied with increased concentration of malondialdehyde suggesting increased oxidative stress. The activities of glutathione peroxidase decreased by about 40%. Though the activity of glutathione reductase decreased by about 58%, addition of FAD in the enzyme assay system showed restoration of lost activity. Additive effect of raised serum tryptophan concentration and ultraviolet radiation in causing damage to the eye lens is suggested.

  9. Effect of heat, UV radiation, and moisture on the decohesion kinetics of inverted organic solar cells

    KAUST Repository

    Rolston, Nicholas

    2017-06-15

    Organic solar cells subjected to environmental stressors such as heat, moisture, and UV radiation can undergo significant mechanical degradation, leading to delamination of layers and device failure. This paper reports the effect these stressors have on the mechanical integrity of active layers and interfaces as measured by subcritical debonding tests, and the in situ evolution of defects and fracture processes is characterized. At elevated temperatures below 50 °C in inert conditions, significant device weakening was observed, an effect we attributed to a temperature-induced P3HT:PCBM delamination mechanism from the underlying ZnO. At 50 °C in ambient conditions with UV exposure—selected to better simulate real-world environments—devices were more resistant to fracture because of an interfacial strengthening effect from increased hydrogen bonding where UV-induced Zn(OH)2 formation reinforced the interface with P3HT:PCBM. This photoinduced hydroxylation mechanism was determined from a decrease in the Zn/O ratio with increased UVA or UVB exposure, and hydroxylation was shown to directly correlate with the resistance to fracture in devices.

  10. UV-CD12: synchrotron radiation circular dichroism beamline at ANKA

    Science.gov (United States)

    Bürck, Jochen; Roth, Siegmar; Windisch, Dirk; Wadhwani, Parvesh; Moss, David; Ulrich, Anne S.

    2015-01-01

    Synchrotron radiation circular dichroism (SRCD) is a rapidly growing technique for structure analysis of proteins and other chiral biomaterials. UV-CD12 is a high-flux SRCD beamline installed at the ANKA synchrotron, to which it had been transferred after the closure of the SRS Daresbury. The beamline covers an extended vacuum-UV to near-UV spectral range and has been open for users since October 2011. The current end-station allows for temperature-controlled steady-state SRCD spectroscopy, including routine automated thermal scans of microlitre volumes of water-soluble proteins down to 170 nm. It offers an excellent signal-to-noise ratio over the whole accessible spectral range. The technique of oriented circular dichroism (OCD) was recently implemented for determining the membrane alignment of α-helical peptides and proteins in macroscopically oriented lipid bilayers as mimics of cellular membranes. It offers improved spectral quality <200 nm compared with an OCD setup adapted to a bench-top instrument, and accelerated data collection by a factor of ∼3. In addition, it permits investigations of low hydrated protein films down to 130 nm using a rotatable sample cell that avoids linear dichroism artifacts. PMID:25931105

  11. Changes induced by UV radiation in the presence of sodium benzoate in films formulated with polyvinyl alcohol and carboxymethyl cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Villarruel, S. [Faculty of Exact Sciences, UNLP (Argentina); Giannuzzi, L.; Rivero, S. [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Pinotti, A., E-mail: acaimpronta@hotmail.com [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Faculty of Engineering, UNLP, La Plata 1900 (Argentina)

    2015-11-01

    This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), and iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of polymer–polymer interaction at a molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of microorganisms. From a physicochemical perspective, the UV treatment of films also changed their morphology rendering them more insoluble in water, turning the functionalized blend films into a potential material to be applied as food packaging. - Highlights: • CMC:PVOH blend films were developed with the addition of sodium benzoate (SB). • Exposition to UV radiation was carried out with sodium benzoate as photoinitiator. • Blend films were exposed to UV radiation to modify their surface morphology. • Low O{sub 2} permeability of UV treated blends allow them to be used as selective packaging. • Efficacy of SB as an antimicrobial agent was examined with and without UV radiation.

  12. Photoacoustic study of curing time by UV laser radiation of a photoresin with different thickness

    Energy Technology Data Exchange (ETDEWEB)

    Pincel, P. Vieyra [UPIITA IPN, Avenida Instituto Politécnico Nacional, No. 2580, Col. Barrio la Laguna Ticomán, Delegación Gustavo A. Madero, C.P. 07340 México, D.F. (Mexico); Jiménez-Pérez, J.L., E-mail: jimenezp@fis.cinvestav.mx [UPIITA IPN, Avenida Instituto Politécnico Nacional, No. 2580, Col. Barrio la Laguna Ticomán, Delegación Gustavo A. Madero, C.P. 07340 México, D.F. (Mexico); Cruz-Orea, A. [Departamento de Física, CINVESTAV-IPN, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, C.P. 07360 México, D.F. (Mexico); Correa-Pacheco, Z.N. [Instituto Politécnico Nacional-Centro de Desarrollo de Productos Bióticos (CEPROBI). Carr. Yautepec–Jojutla, km 6. San Isidro, C.P. 62730 Yautepec, Morelos (Mexico); Rosas, J. Hernández [UPIITA IPN, Avenida Instituto Politécnico Nacional, No. 2580, Col. Barrio la Laguna Ticomán, Delegación Gustavo A. Madero, C.P. 07340 México, D.F. (Mexico)

    2015-04-20

    Highlights: • The curing of a resin in the presence of a UV laser radiation was studied. • Open photoacoustic cell technique was used to characterize the curing of the resin. • The curing of the resin as a function of time was studied. • A parabolic behavior of the resin thickness, as a function of time was observed. • UV–vis and FTIR spectroscopy were employed to characterize the resin. - Abstract: This paper deals with the study of the cure of a resin in the presence of a UV laser radiation used as the excitation source, operated at λ = 405 nm, with an output power of 20 mW. The open photoacoustic cell (OPC) technique was used to study the curing of the resins as a function of time. The curing characteristic time values were τ = 10.43, 20.99, 30.18, 45.84, 67.59 and 89.55 s for the resin thicknesses of 1000, 2000, 3000, 4000, 5000 and 6000 μm, respectively. A parabolic behavior of the resin thickness, as a function of the curing characteristic time, was obtained. UV–vis spectroscopy and infrared Fourier transform spectroscopy (FTIR) techniques were employed to characterize the resin in order to study the optical absorption and the chemical bonds, respectively. Our work has applications in the manufacture of 3D printing parts for applications, among others, in medicine.

  13. Extreme total column ozone events and effects on UV solar radiation at Thessaloniki, Greece

    Science.gov (United States)

    Fragkos, K.; Bais, A. F.; Fountoulakis, I.; Balis, D.; Tourpali, K.; Meleti, C.; Zanis, P.

    2016-11-01

    Thirty years of total ozone column (TOC) measurements conducted by a Brewer spectrophotometer, operating in Thessaloniki (40.6°) since March 1982, have been analyzed using the statistical extreme value theory for the identification of extreme TOC events. About 12 % of the total number of days with TOC measurements were identified as extreme-low and ˜15 % as extreme-high events. The influence of the extreme-low events on the annual mean TOC values is up to ˜18 DU, while the extreme-high events show lower impact (up to 12 DU). Removing the extreme events from the time series results in smoother year-to-year variability and reduction of the small long-term linear trend (-0.08 %/year) by a factor of 2. Furthermore, we examined the impact of the extreme events on the noon erythemal irradiance under clear skies, and we provide evidence that even under extreme-low TOC conditions, the UV radiation levels are determined to a great extent by the aerosol optical depth. Although the influence of aerosols is evident during all seasons, for spring and summer, the sensitivity of UV radiation is larger, probably due to the different nature of the aerosols over Thessaloniki during these seasons.

  14. Attenuation by clouds of UV radiation for low stratospheric ozone conditions

    Science.gov (United States)

    Orte, Facundo; Wolfram, Elian; Salvador, Jacobo; D'Elia, Raúl; Quiroga, Jonathan; Quel, Eduardo; Mizuno, Akira

    2017-02-01

    Stratospheric poor ozone air masses related to the polar ozone hole overpass subpolar regions in the Southern Hemisphere during spring and summer seasons, resulting in increases of surface Ultraviolet Index (UVI). The impact of these abnormal increases in the ultraviolet radiation could be overestimated if clouds are not taking into account. The aim of this work is to determine the percentage of cases in which cloudiness attenuates the high UV radiation that would reach the surface in low total ozone column situations and in clear sky hypothetical condition for Río Gallegos, Argentina. For this purpose, we analysed UVI data obtained from a multiband filter radiometer GUV-541 (Biospherical Inc.) installed in the Observatorio Atmosférico de la Patagonia Austral (OAPA-UNIDEF (MINDEF - CONICET)) (51 ° 33' S, 69 ° 19' W), Río Gallegos, since 2005. The database used covers the period 2005-2012 for spring seasons. Measured UVI values are compared with UVI calculated using a parametric UV model proposed by Madronich (2007), which is an approximation for the UVI for clear sky, unpolluted atmosphere and low surface albedo condition, using the total ozone column amount, obtained from the OMI database for our case, and the solar zenith angle. It is observed that ˜76% of the total low ozone amount cases, which would result in high and very high UVI categories for a hypothetical (modeled) clear sky condition, are attenuated by clouds, while 91% of hypothetical extremely high UVI category are also attenuated.

  15. Involvement of cathepsin B in mitochondrial apoptosis by p-phenylenediamine under ambient UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Shruti; Amar, Saroj Kumar [Photobiology Division, CSIR – Indian Institute of Toxicology Research, Post Box No. 80, M.G. Marg, Lucknow 226001, Uttar Pradesh (India); Academy of Scientific and Innovative Research, CSIR-IITR Campus, Lucknow (India); Dubey, Divya; Pal, Manish Kumar [Photobiology Division, CSIR – Indian Institute of Toxicology Research, Post Box No. 80, M.G. Marg, Lucknow 226001, Uttar Pradesh (India); Singh, Jyoti [Photobiology Division, CSIR – Indian Institute of Toxicology Research, Post Box No. 80, M.G. Marg, Lucknow 226001, Uttar Pradesh (India); Academy of Scientific and Innovative Research, CSIR-IITR Campus, Lucknow (India); Verma, Ankit; Kushwaha, Hari Narayan [Photobiology Division, CSIR – Indian Institute of Toxicology Research, Post Box No. 80, M.G. Marg, Lucknow 226001, Uttar Pradesh (India); Ray, Ratan Singh, E-mail: ratanray.2011@rediffmail.com [Photobiology Division, CSIR – Indian Institute of Toxicology Research, Post Box No. 80, M.G. Marg, Lucknow 226001, Uttar Pradesh (India)

    2015-12-30

    Highlights: • Photodegradation and formation of photoproduct. • Involvement of ROS in PPD phototoxicity. • Role of ROS in DNA damage, CPD and micronuclei formation. • PPD induced lysosomal destabilization and release of cathepsin B. • Cleavage of Bid and activation of mitochondrial apoptosis. - Abstract: Paraphenylenediamine (PPD), a derivative of paranitroaniline has been most commonly used as an ingredient of oxidative hair dye and permanent tattoos. We have studied the phototoxic potential of PPD under ambient ultraviolet radiation. PPD is photodegraded and form a novel photoproduct under UV A exposure. PPD shows a concentration dependent decrease in cell viability of human Keratinocyte cells (HaCaT) through MTT and NRU test. Significant intracellular ROS generation was measured by DCFDA assay. It caused an oxidative DNA damage via single stranded DNA breaks, micronuclei and CPD formation. Both lysosome and mitochondria is main target for PPD induced apoptosis which was proved through lysosomal destabilization and release of cathepsin B by immunofluorescence, real time PCR and western blot analysis. Cathepsin B process BID to active tBID which induces the release of cytochrome C from mitochondria. Mitochondrial depolarization was reported through transmission electron microscopy. The cathepsin inhibitor reduced the release of cytochrome C in PPD treated cells. Thus study suggests that PPD leads to apoptosis via the involvement of lysosome and mitochondria both under ambient UV radiation. Therefore, photosensitizing nature of hair dye ingredients should be tested before coming to market as a cosmetic product for the safety of human beings.

  16. Luminescent emission of LiF: Mg, Ti exposed to UV radiation; Emision luminiscente del LiF: Mg, Ti expuesto a la radiacion UV

    Energy Technology Data Exchange (ETDEWEB)

    Estrada G, A. [Estudiante de Facultad de Ciencias, UNAM, Circuito Exterior, 04500 Mexico D.F. (Mexico); Castano M, V.M. [Centro de Fisica Aplicada y Tecnologia Avanzada, UNAM, Campus Juriquilla, Queretaro (Mexico); Cruz Z, E.; Garcia F, F. [Instituto de Ciencias Nucleares UNAM, A.P. 70-543 Mexico D.F. (Mexico)

    2002-07-01

    It was investigated the luminescent emission stimulated by heat (Tl) of LiF: Mg, Ti crystals which were exposed to UV radiation coming from a mercury lamp. Since this crystal depends on the thermal history, it has been used a thermal treatment consisting of a baking at 380 C during one hour for each reading and they were irradiated with UV. The brilliance curves between 5 and 840 minutes of exposure in the face of UV light were obtained. An important loss in the response, starting from 150 minutes of irradiation was observed. Also the relative intensity of the brilliance curve decay when the crystals being stored in darkness and room temperature conditions, which is according to the results in the literature about. (Author)

  17. Effects of stron UV-B radiation on air chemistry and climate; Auswirkungen verstaerkter UV-B-Strahlung auf Luftchemie und Klima

    Energy Technology Data Exchange (ETDEWEB)

    Schoenemeyer, T.; Seidl, W.; Forkel, R.; Kuhn, M.; Wehrhahn, J.; Grell, G.

    1998-07-01

    Effects of enhanced UV radiation on air chemistry, climate and climate change were investigated, and its interactions with other environmental problems like acidification of soil and surface water, reduction in the variety of species, and desertification were gone into. [German] In der vorliegenden Arbeit wurden die bisher vorliegenden Erkenntnisse ueber die Auswirkungen erhoehter UV-Strahlung infolge des Abbaus von Ozon in der Stratosphaere auf Luftchemie und Klima zusammengetragen. Die Problematik wird in ihrer ganzen Breite beleuchtet und dabei deutlich gemacht, ueber welche zahlreichen Mechanismen eine erhoehte UV-Strahlung auch zu Klimaaenderungen fuehren kann. Dies unterstreicht die Notwendigkeit, Verknuepfungen mit anderen Umweltproblemen wie der Versauerung des Bodens und von Gewaessern, der Abnahme der Artenvielfalt sowie der zunehmenden Wuestenbildung herzustellen. (orig.)

  18. Operational surface UV radiation product from GOME-2 and AVHRR/3 data

    Directory of Open Access Journals (Sweden)

    J. Kujanpää

    2015-10-01

    Full Text Available The surface ultraviolet (UV radiation product, version 1.20, generated operationally in the framework of the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT is described. The product is based on the total ozone column derived from the measurements of the second Global Ozone Monitoring Experiment (GOME-2 instrument aboard EUMETSAT's polar orbiting meteorological operational (Metop satellites. Cloud cover is taken into account by retrieving cloud optical depth from the channel 1 reflectance of the third Advanced Very High-Resolution Radiometer (AVHRR/3 instrument aboard both Metop in the morning orbit and Polar Orbiting Environmental Satellites (POES of the National Oceanic and Atmospheric Administration (NOAA in the afternoon orbit. In addition, more overpasses are used at high latitudes where the swaths of consecutive orbits overlap. The input satellite data are received from EUMETSAT's Multicast Distribution System (EUMETCast. The surface UV product includes daily maximum dose rates and integrated daily doses with different biological weighting functions, integrated ultraviolet B (UVB and ultraviolet A (UVA radiation, solar noon UV index and daily maximum photolysis frequencies of ozone and nitrogen dioxide at the surface level. The quantities are computed in a 0.5°×0.5° regular latitude–longitude grid and stored as daily files in the hierarchical data format (HDF5 within 2 weeks from sensing. The product files are archived in the O3M SAF distributed archive and can be ordered via the EUMETSAT Data Centre.

  19. Reduction of Solar UV Radiation Due to Urban High-Rise Buildings--A Coupled Modelling Study.

    Directory of Open Access Journals (Sweden)

    Ka-Ming Wai

    Full Text Available Solar UV radiation has both adverse and beneficial effects to human health. Using models (a radiative transfer model coupled to a building shading model, together with satellite and surface measurements, we studied the un-obstructed and obstructed UV environments in a sub-tropical urban environment featured with relatively high pollution (aerosol loadings and high-rise buildings. Seasonal patterns of the erythemal UV exposure rates were governed by solar zenith angles, seasonal variations of aerosol loadings and cloud effects. The radiative transfer modelling results agreed with measurements of erythemal UV exposure rates and spectral irradiances in UVA and UVB ranges. High-rise buildings and narrow road width (height to width, H/W, ratios up to 15 reduced the modelled total UV (UVA+UVB radiation and leave 10% of the un-obstructed exposure rate at ground-level at noon. No more than 80% of the un-obstructed exposure rate was received in the open area surrounded by 20-storey buildings. Our modelled reduction of UVB radiation in the urban environment was consistent with similar measurements obtained for Australia. However, our results in more extreme environments (higher H/W ratios were for the first time reported, with 18% of the un-obstructed exposure rate remained at the ground-level center of the street canyon.

  20. Reduction of Solar UV Radiation Due to Urban High-Rise Buildings – A Coupled Modelling Study

    Science.gov (United States)

    Wai, Ka-Ming; Yu, Peter K. N.; Lam, Ka-Se

    2015-01-01

    Solar UV radiation has both adverse and beneficial effects to human health. Using models (a radiative transfer model coupled to a building shading model), together with satellite and surface measurements, we studied the un-obstructed and obstructed UV environments in a sub-tropical urban environment featured with relatively high pollution (aerosol) loadings and high-rise buildings. Seasonal patterns of the erythemal UV exposure rates were governed by solar zenith angles, seasonal variations of aerosol loadings and cloud effects. The radiative transfer modelling results agreed with measurements of erythemal UV exposure rates and spectral irradiances in UVA and UVB ranges. High-rise buildings and narrow road width (height to width, H/W, ratios up to 15) reduced the modelled total UV (UVA+UVB) radiation and leave 10% of the un-obstructed exposure rate at ground-level at noon. No more than 80% of the un-obstructed exposure rate was received in the open area surrounded by 20-storey buildings. Our modelled reduction of UVB radiation in the urban environment was consistent with similar measurements obtained for Australia. However, our results in more extreme environments (higher H/W ratios) were for the first time reported, with 18% of the un-obstructed exposure rate remained at the ground-level center of the street canyon. PMID:26263507

  1. Reduction of Solar UV Radiation Due to Urban High-Rise Buildings--A Coupled Modelling Study.

    Science.gov (United States)

    Wai, Ka-Ming; Yu, Peter K N; Lam, Ka-Se

    2015-01-01

    Solar UV radiation has both adverse and beneficial effects to human health. Using models (a radiative transfer model coupled to a building shading model), together with satellite and surface measurements, we studied the un-obstructed and obstructed UV environments in a sub-tropical urban environment featured with relatively high pollution (aerosol) loadings and high-rise buildings. Seasonal patterns of the erythemal UV exposure rates were governed by solar zenith angles, seasonal variations of aerosol loadings and cloud effects. The radiative transfer modelling results agreed with measurements of erythemal UV exposure rates and spectral irradiances in UVA and UVB ranges. High-rise buildings and narrow road width (height to width, H/W, ratios up to 15) reduced the modelled total UV (UVA+UVB) radiation and leave 10% of the un-obstructed exposure rate at ground-level at noon. No more than 80% of the un-obstructed exposure rate was received in the open area surrounded by 20-storey buildings. Our modelled reduction of UVB radiation in the urban environment was consistent with similar measurements obtained for Australia. However, our results in more extreme environments (higher H/W ratios) were for the first time reported, with 18% of the un-obstructed exposure rate remained at the ground-level center of the street canyon.

  2. [Physiological responses of 2-year-old Acer davidii seedings to short-term enhanced UV-B radiation].

    Science.gov (United States)

    Zuo, Yuanyuan; Liu, Qing; Lin, Bo; He, Hai

    2005-09-01

    At the Maoxian Ecological Experimental Station of Chinese Academy of Sciences in northwest Sichuan Province, 2-year-old native maple(Acer davidii) seedlings were potted outdoors with enhanced UV-B radiation(280 - 320 nm) of 0.27 W x m(-2) (7.7 kJ x m(-2) x d(-1)), which was approximated to the predicted enhanced UV-B reaching the earth surface when stratosphere ozone was depleted by 15% in the local area, with the control plant received ambient UV-B. The gas exchange index and chlorophyll fluorescence, and the contents of chlorophyll and UV-absorbing compounds were examined after 50 days of the radiation. The results showed that enhanced UV-B radiation significantly lowered the maximal net photosynthetic rate (CK = 6.214, TR = 4.452), raised the dark respiration rate(CK = 0.413, TR = 1.295) and light compensation point (CK = 21.629, TR = 59.861), but had little effect on quantum yield (CK = 0.021, TR = 0.032). Under enhanced UV-B radiation, the diurnal changes in net photosynthetic rate, water use efficiency, quantum efficiency of photosystem II centers (Fv/Fm), and quantum yield of photosystem II photochemistry (phi(pspi)) were reduced, chlorophyll a, total chlorophylls, and chlorophyll a/b (CK= 16.23, 5.39, TR = 13.17, 4.93) were also markedly reduced, but chlorophyll b remained nearly unchanged. Contrary to the previous studies, enhanced UV-B radiation decreased the content of UV-absorbing compounds (CK = 0.87, TR = 0.79) in 2-year-old Acer davidii seedling leaves, indicating that the measurement of leaf UV-B absorbing compounds didn't necessarily provide a good indicator of plant tolerance to UV-B. It could be concluded that enhanced UV-B radiation had some inhibitory effects on the photosynthesis of Acer davidii seedlings. Long-term researches are necessary to confirm this conclusion.

  3. Absorption of uv-radiation by Chibro {sup trademark} -Uvelin eye drops; Absorption von Chibro {sup trademark} -Uvelin Augentropfen fuer UV-Schutz

    Energy Technology Data Exchange (ETDEWEB)

    Schreder, J.G.; Blumthaler, M. [Innsbruck Univ. (Austria). Inst. fuer Medizinische Physik; Daxer, A. [Krankenhaus der Landeshauptstadt St. Poelten (Austria). Abt. fuer Augenheilkunde; Ettl, A. [Krankenhaus der Landeshauptstadt St. Poelten (Austria). Abt. fuer Orthoptik

    1998-12-31

    The preparation Chibro {sup trademark} -Uvelin is recommended against both solar and artificial uv-radiation. At wavelengths greater than 290 nm and at an effective layer thickness of 10 {mu}m measurements with a high resolution doublemonochromator showed a transmission larger than 90%. The solar spectrum is characterised by almost no irradiance on the earth`s surface for wavelengths smaller than 290 nm due to absorption in the atmospheric ozon layer. Therefore, no significant protective effect of the eye-drops against keratitis and cataract under solar exposure can be expected. A significantly better sagging of the radiation of artificial UV-sources with a high amount of UV-C is reached. The recommended application as chemical protective goggles in this spectral range is not permissible. (orig.) [Deutsch] Das apothekenpflichtige Praeparat Chibro {sup trademark} -Uvelin wird zum Schutz gegen solare und kuenstliche ultraviolette Strahlung empfohlen. Eigene Messungen mit einem Doppelmonochromator ergaben fuer Wellenlaengen groesser 290 nm sowie fuer realistische Fluessigkeitsfilme von 10 {mu}m Dicke eine Transparenz von groesser 90%. Das Sonnenspektrum weist aufgrund der Ozonabsorption in der Atmosphaere auf der Erdoberflaeche keine relevante Strahlung mit Wellenlaengen kleiner 290 nm auf. Fuer solare Strahlung ist daher kein Schutz gegen Keratitis und Katarakt gegeben. Die Strahlung kuenstlicher Lichtquellen mit einem hohen UV-C Anteil wird deutlich abgeschwaecht. Die empfohlene Verwendung als `chemische Schutzbrille` ist auch in diesen Spektralbereich nicht zulaessig. (orig.)

  4. Study of cloud enhanced surface UV radiation at the atmospheric observatory of Southern Patagonia, Río Gallegos, Argentina

    Science.gov (United States)

    Wolfram, Elian A.; Salvador, Jacobo; Orte, Facundo; Bulnes, Daniela; D'Elia, Raul; Antón, Manuel; Alados-Arboledas, Lucas; Quel, Eduardo

    2013-05-01

    Ozone and ultraviolet (UV) radiation are two important issues in the study of Earth's atmosphere. The anthropogenic perturbation of the ozone layer has induced change in the amount of UV radiation that reaches the Earth's surface, mainly through the Antarctic ozone hole. Also clouds have been identified as the main modulator of UV amount over short time scales. While clouds can decrease direct radiation, they can produce an increase in the diffuse component, and as a consequence the surface UV radiation may be higher than during an equivalent clear sky scenario. In particular this situation can be important when a low ozone column and partially cloud coverered skies occur simultaneously. These situations happen frequently in southern Patagonia, where the CEILAP Lidar Division has established the Atmospheric Observatory of Southern Patagonia, an atmospheric remote sensing site near the city of Río Gallegos (51°55'S, 69°14'W). In this paper, the impact of clouds on UV radiation is investigated by the use of ground based measurements from the passive remote sensing instruments operating at this site, mainly broad and moderate narrow band filter radiometers. Cloud modification factors (CMF, ratio between the measured UV radiation in a cloudy sky and the simulated radiation under cloud-free conditions) are evaluated for the study site. CMFs higher than 1 are found during spring and summer time, when lower total ozone columns, higher solar elevations and high cloud cover occur simultaneously, producing extreme erythemal irradiance at the ground surface. Enhancements as high as 25% were registered. The maximum duration of the enhancement was around 30 minutes. This produces dangerous sunbathing conditions for the Río Gallegos citizen.

  5. Flavonols Protect Against UV Radiation-Induced Thymine Dimer Formation in an Artificial Skin Mimic.

    Science.gov (United States)

    Maini, Sabia; Fahlman, Brian M; Krol, Ed S

    2015-01-01

    Exposure of skin to ultraviolet light has been shown to have a number of deleterious effects including photoaging, photoimmunosuppression and photoinduced DNA damage which can lead to the development of skin cancer. In this paper we present a study on the ability of three flavonols to protect EpiDerm™, an artificial skin mimic, against UV-induced damage. EpiDerm™ samples were treated with flavonol in acetone and exposed to UVA (100 kJ/m(2) at 365 nm) and UVB (9000 J/m(2) at 310 nm) radiation. Secretion of matrix metalloproteinase-1 (MMP-1) and tumor necrosis factor-α (TNF-a) were determined by ELISA, cyclobutane pyrimidine dimers were quantified using LC-APCI-MS. EpiDerm™ treated topically with quercetin significantly decreased MMP-1 secretion induced by UVA (100 µM) or UVB (200 µM) and TNF-a secretion was significantly reduced at 100 µM quercetin for both UVA and UVB radiation. In addition, topically applied quercetin was found to be photostable over the duration of the experiment. EpiDerm™ samples were treated topically with quercetin, kaempferol or galangin (52 µM) immediately prior to UVA or UVB exposure, and the cyclobutane thymine dimers (T-T (CPD)) were quantified using an HPLC-APCI MS/MS method. All three flavonols significantly decreased T-T (CPD) formation in UVB irradiated EpiDerm™, however no effect could be observed for the UVA irradiation experiments as thymine dimer formation was below the limit of quantitation. Our results suggest that flavonols can provide protection against UV radiation-induced skin damage through both antioxidant activity and direct photo-absorption. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  6. An enhancing effect of visible light and UV radiation on phenolic compounds and various antioxidants in broad bean seedlings

    Science.gov (United States)

    Hasaneen, Mohammed Naguib Abdel-Ghany; Abdel-Aziz, Heba Mahmoud Mohammed

    2010-01-01

    Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV radiation. PMID:20505357

  7. Thermoluminescence dependence on the wavelength of monochromatic UV-radiation in Cu-doped KCl and KBr at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Perez R, A.; Piters, T.; Aceves, R.; Rodriguez M, R.; Perez S, R., E-mail: rperez@cifus.uson.mx [Universidad de Sonora, Departamento de Investigaciones en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

    2014-08-15

    Thermoluminescence (Tl) dependence on the UV irradiation wavelengths from 200 to 500 nm in Cu-doped KCl and KBr crystals with different thermal treatment has been analyzed. Spectrum of the Tl intensity of each material show lower intensity at wavelengths longer than 420 nm. The Tl intensity depends on the irradiation wavelength. Structure of the Tl intensity spectrum of each sample is very similar to the structure of its optical absorption spectrum, indicating that at each wavelength, monochromatic radiation is absorbed to produce electronic transitions and electron hole pairs. Thermoluminescence of materials with thermal treatment at high temperature shows electron-hole trapping with less efficiency. The results show that Cu-doped alkali-halide materials are good detectors of a wide range of UV monochromatic radiations and could be used to measure UV radiation doses. (Author)

  8. He-Ne laser treatment improves the photosynthetic efficiency of wheat exposed to enhanced UV-B radiation

    Science.gov (United States)

    Chen, Huize; Han, Rong

    2014-10-01

    The level of ultraviolet-B (UV-B) radiation on the Earth’s surface has increased due to depletion of the ozone layer. Here, we explored the effects of continuous wave He-Ne laser irradiation (632 nm, 5 mW mm-2, 2 min d-1) on the physiological indexes of wheat seedlings exposed to enhanced UV-B radiation (10 KJ m-2 d-1) at the early growth stages. Wheat seedlings were irradiated with enhanced UV-B, He-Ne laser treatment or a combination of the two. Enhanced UV-B radiation had deleterious effects on wheat photosynthesis parameters including photosystem II (chlorophyll content, Hill reaction, chlorophyll fluorescence parameters, electron transport rate (ETR), and yield), the thylakoid (optical absorption ability, cyclic photophosphorylation, Mg2+-ATPase, and Ca2+-ATPase) and some enzymes in the dark reaction (phosphoenolpyruvate carboxylase (PEPC), carbonic anhydrase (CA), malic dehydrogenase (MDH), and chlorophyllase). These parameters were improved in UV-B-exposed wheat treated with He-Ne laser irradiation; the parameters were near control levels and the enzyme activities increased, suggesting that He-Ne laser treatment partially alleviates the injury caused by enhanced UV-B irradiation. Furthermore, the use of He-Ne laser alone had a favourable effect on seedling photosynthesis compared with the control. Therefore, He-Ne laser irradiation can enhance the adaptation capacity of crops.

  9. Impact of shortwave ultraviolet (UV-C) radiation on the antioxidant activity of thyme (Thymus vulgaris L.).

    Science.gov (United States)

    Dogu-Baykut, Esra; Gunes, Gurbuz; Decker, Eric Andrew

    2014-08-15

    Thyme is a good source of antioxidant compounds but it can be contaminated by microorganisms. An experimental fluid bed ultraviolet (UV) reactor was designed for microbial decontamination of thyme samples and the effect of shortwave ultraviolet light (UV-C) radiation on antioxidant properties of thyme was studied. Samples were exposed to UV-C radiation for 16 or 64 min. UV-C treatment led to 1.04 and 1.38 log CFU/g reduction of total aerobic mesophilic bacteria (TAMB) counts. Hunter a(∗) value was the most sensitive colour parameter during UV-C treatment. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of extracts was not significantly affected by UV-C. Addition of thyme extracts at 0.15 and 0.3 μmol GAE/ml emulsion delayed the formation of lipid hydroperoxides and headspace hexanal in the 5.0%(wt) corn oil-in-water emulsion from 4 to 9 and 14 days, respectively. No significant changes in oxidation rates were observed between UV-C treated and untreated samples at same concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The effect of solar UV radiation of four plant species occurring in a coastal grassland vegetation in The Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Tosserams, M.; Rozema, J. [Vrije Univ., Dept. of Ecology and Ecotoxicology, Amsterdam (Netherlands); Pais, A. de Sa [Univ. de Tras-os-Montes e Alto Douro, Vila Real (Portugal)

    1996-09-01

    During the summer of 1992, growth and some physiological parameters of four native plant species occurring in a coastal grassland in The Netherlands, were studied after reduction of solar UV irradiance using different cut-off filters. Biomass production, morphology and photosynthesis of all species tested were unaffected by the different treatments. Litter production of Plantago lanceolata was increased in the absence of the total UV waveband, indicating a possible role for this waveband in plant senescence. Depletion of the total UV waveband from sunlight resulted in alterations in biomass allocation in Calamagrostis epigeios and Urtica dioica while no changes were observed in P. lanceolatata and Verbascum thapsus. In C. epigeios and increase in the specific leaf area was observed, whereas in U. dioica root weight per total plant weight was decreased resulting in an increase in the shoot/root ratio. Both photosynthetic and UV-absorbing pigment concentrations were altered by the different filter applications. When compared to control plants receiving full sunlight, depletion of UV-B resulted in a significant increase in chlorophyll concentration in U. dioica leaves, this however did not affect photosynthetic rate. The presence of UV-B radiation enhanced the UV-absorbance of leaf extract of all species except P. lanceolata. Optical characteristics of the leaves were also changed. Both the quantity (P. lanceolata and U. dioica) and the quality (all species) of radiation transmitted by the leaves was affected by the different treatments. (au) 44 refs.

  11. 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.

  12. Application of SV40 T-transformed human corneal epithelial cells to evaluate potential irritant chemicals for in vitro alternative eye toxicity.

    Science.gov (United States)

    Kim, Cho-Won; Park, Geon-Tae; Bae, Ok-Nam; Noh, Minsoo; Choi, Kyung-Chul

    2016-01-01

    Assessment of eye irritation potential is important to human safety, and it is necessary for various cosmetics and chemicals that may contact the human eye. Until recently, the Draize test was considered the standard method for estimating eye irritation, despite its disadvantages such as the need to sacrifice many rabbits for subjective scoring. Thus, we investigated the cytotoxicity and inflammatory response to standard eye irritants using SV40 T-transformed human corneal epithelial (SHCE) cells as a step toward development of an animal-free alternative eye irritation test. MTT and NRU assays of cell viability were performed to investigate the optimal experimental conditions for SHCE cell viability when cells were exposed to sodium dodecyl sulfate (SDS) as a standard eye irritant at 6.25×10(-3) to 1×10(-1)%. Additionally, cell viability of SHCE cells was examined in response to six potential eye irritants, benzalkonium chloride, dimethyl sulfoxide, isopropanol, SDS, Triton X-100 and Tween 20 at 5×10(-3) to 1×10(-1)%. Finally, we estimated the secretion level of cytokines in response to stimulation by eye irritants in SHCE cells. SHCE cells showed a good response to potential eye irritants when the cells were exposed to potential irritants for 10min at room temperature (RT), and cytokine production increased in a concentration-dependent manner, indicating that cytotoxicity and cytokine secretion from SHCE cells may be well correlated with the concentrations of irritants. Taken together, these results suggest that SHCE cells could be an excellent alternative in vitro model to replace in vivo animal models for eye irritation tests. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Simvastatin and intracellular pH regulation by the Na+/H+ antiport of SV40-virus-transformed human MRC5 fibroblasts.

    Science.gov (United States)

    Davies, J E; Ng, L L

    1993-06-01

    1. Inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase by simvastatin leads to inhibition of both cell growth and Na+/H+ antiport activity. The effect of simvastatin on intracellular pH and Na+/H+ antiport activity was therefore studied on an adherent cell line, the SV40-virus-transformed MRC5 human fibroblast. 2. Simvastatin led to a dose-dependent decrease in intracellular pH, attributed to a reduction in Na+/H+ exchange, together with a rounding of cell shape. Mevalonate (1 mmol/l) prevented these effects of simvastatin, and when added after inhibition of the antiport by simvastatin, reversed these changes within 1-2h. 3. The phenomenon of mevalonate reversal of antiport inhibition by simvastatin was not sensitive to cycloheximide, indicating its post-translational nature. This was also consistent with the short period of incubation with mevalonate leading to reversal of antiport inhibition (1-2 h). These changes in intracellular pH regulation were not due to alterations in cell cholesterol content. 4. A variety of inhibitors of post-translational processes, such as N-linked glycosylation (tunicamycin), phosphorylation (staurosporine), isoprenylation (farnesol, limonene), and of pertussis-toxin-sensitive G-proteins or calmodulin (W7), had no effect on the reversal by mevalonate of simvastatin-induced changes in Na+/H+ antiport activity. 5. N-Ethylmaleimide (50 mumol/l for 5 min) prevented mevalonate reversing the effects of simvastatin, suggesting the importance of thiol groups in the phenomenon of reversal of the inhibition of Na+/H+ antiport activity by simvastatin. Furthermore, concurrent incubation of simvastatin-treated cells with dithiothreitol (1 mmol/l) and N-ethylmaleimide restored the ability of mevalonate to reverse the inhibitory effects of simvastatin on Na+H+ antiport activity.

  14. Effect of enhanced UV-B radiation on pollen quantity, quality, and seed yield in Brassica rapa (Brassicaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Demchik, S.M.; Day, T.A. [West Virginia Univ., Morgantown, WV (United States)

    1996-05-01

    Three experiments examined the influence of ultraviolet-B radiation (UV-B; 280-320 nm) exposure on reproduction in Brassica rapa (Brassicacaeae). Plants were grown in a greenhouse under three biologically effective UV-B levels that stimulated either an ambient stratospheric ozone level (control), 16% ({open_quotes}low enhanced{close_quotes}), or 32% ({open_quotes}high enhanced{close_quotes}) ozone depletion levels at Morgantown, WV, USA in mid-March. In the first experiment,pollen production and viability per flower were reduced by {approx}50% under both enhanced UV-B levels relative to ambient controls. While plants under high-enhanced UV-B produced over 40% more flowers than plants under the two lower UV-B treatments, whole-plant production of viable pollen was reduced under low-enhanced UV-B to 34% of ambient controls. In the second experiment, the influence of source-plant UV-B exposure on in vitro pollen from plants was examined and whether source-plant UV-B exposure influenced in vitro pollen germination and viability. Pollen from plants under both enhanced-UV-B was reduced from 65 to 18%. Viability of the pollen from plants grown under both enhanced UV-B treatments was reduced to a much lesser extent: only from {approx}43 to 22%. Thus, ambient source-plant pollen was more sensitive to enhanced UV-B levels to fertilize plants growing under ambient-UV-B levels, and assessed subsequent seed production and germination. Seed abortion rates were higher in plants pollinated with pollen from the enhanced UV-B treatments, than from ambient UV-B. Despite this, seed yield (number and mass) per plant was similar, regardless of the UV-B exposure of their pollen source. Our findings demonstrate that enhanced UV-B levels associated with springtime ozone depletion events have the capacity to substantially reduce viable pollen production, and could ultimately reduce reproductive success of B. rapa. 37 refs., 4 figs., 2 tabs.

  15. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana

    Energy Technology Data Exchange (ETDEWEB)

    Won, Eun-Ji; Han, Jeonghoon [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Yeonjung; Kumar, K. Suresh; Shin, Kyung-Hoon [Department of Marine Sciences and Convergent Technology, College of Science and Technology, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Su-Jae [Department of Life Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Heum Gi, E-mail: hgpark@gwnu.ac.kr [Department of Marine Resource Development, College of Life Sciences, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-08-15

    Highlights: • UV-B radiation induced a significant reduction of the re-brooding rate of ovigerous females. • A dose-dependent decrease in food ingestion and the rate of assimilation to the body upon UV radiation. • Expression of base excision repair-associated and hsp chaperoning genes was significantly increased upon UV radiation in P. nana. - Abstract: To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0–3 kJ/m{sup 2}) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7–87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (P < 0.05) in food ingestion and the rate of assimilation to the body in response to UV radiation, implying that P. nana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1 kJ/m{sup 2} of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana.

  16. [Prognosis of yeast cells recovery after simultaneous exposure to UV-radiation and hyperthermia].

    Science.gov (United States)

    Komarova, L N; Tkhabisimova, M D; Petin, V G

    2007-01-01

    The results of experimental investigations of survival of diploid yeast cells Saccharomyces cerevisiae (strain XS800) after simultaneous exposure to UV-radiation (254 nm) and hyperthermia (53-57 degrees C) have been described. It was shown that the portion of cells capable of recovery in innutrient medium after the action of these agents decreased with the increasing of temperature under which the irradiation was occurred. Mathematical model taking into account the synergistic interaction was suggested for quantitative prediction of irreversible component after combined actions of these agents. A good correspondence between experimental data and model predictions has been demonstrated. The importance of the results obtained for the interpretation of the synergistic interaction mechanisms are discussed.

  17. Neural Network on Photodegradation of Octylphenol using Natural and Artificial UV Radiation

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2011-09-01

    Full Text Available The present paper comes up with an experimental design meant to point out the factors interferingin octylphenol’s degradation in surface waters under solar radiation, underlining each factor’sinfluence on the process observable (concentration of p-octylphenol. Multiple linear regressionanalysis and artificial neural network (Multi-Layer Perceptron type were applied in order to obtaina mathematical model capable to explain the action of UV-light upon synthetic solutions of OP inultra-pure water (MilliQ type. Neural network proves to be the most efficient method in predictingthe evolution of OP concentration during photodegradation process. Thus, determination in neuralnetwork’s case has almost double value versus the regression analysis.

  18. Study of the Effect of UV Radiation on the Decomposition of 4-Chloro-2-Methylphenoxyacetic Acid

    Science.gov (United States)

    Tchaikovskaya, O. N.; Karetnikova, E. A.; Sokolova, I. V.; Mayer, G. V.

    2013-12-01

    The influence of UV radiation wavelength on the disappearance kinetics of 4-chloro-2-methylphenoxyacetic acid (MCPA) in the presence of activated sludge and humic acids has been examined. Variations in the kinetic curves of MCPA removal in the presence of humic acids were determined from results on accumulation of carbon dioxide gas. Spectral-luminescence and chromato-mass-spectrometry data reveal the presence in the medium of the biotransformation product 2-methyl-4-chlorophenol, which is utilized after 14 days. Addition of humic acids, on the one hand, reduced the rates of subsequent biodecomposition of MCPA. On the other hand, in the process of transformation of the herbicide in the presence of humic acids a photobioproduct was detected which does not contain chlorine: 2-methylphenoxyacetic acid.

  19. Rapid induction of omega-3 fatty acids (EPA) in Nannochloropsis sp. by UV-C radiation.

    Science.gov (United States)

    Sharma, Kalpesh; Schenk, Peer M

    2015-06-01

    Omega-3 fatty acids, such as eicosapentaenoic acid (EPA), provide substantial health benefits. As global fish stocks are declining and in some cases are contaminated with heavy metals, there is a need to find more sustainable land-based sources of these essential fatty acids. The oleaginous microalga Nannochloropsis sp. has been identified as a highly efficient producer of omega-3 fatty acids. In this study, we present a new process to rapidly induce biosynthesis of essential fatty acids, including EPA in Nannochloropsis sp. BR2. Short exposure to UV-C at a dose of 100 or 250 mJ/cm(2) led to a significant increase in total cellular lipid contents when compared to mock-treated controls. A low dosage of 100 mJ/cm(2) also led to a twofold increase in total EPA content within 24 h that constituted 30% of total fatty acids and up to 12% of total dry weight at higher dosages. UV-C radiation may find uses as an easily applicable external inducer for large-scale production of omega-3 production from microalgae. © 2015 Wiley Periodicals, Inc.

  20. Investigation of the sunscreen octocrylene's interaction with amino acid analogs in the presence of UV radiation.

    Science.gov (United States)

    Karlsson, Isabella; Persson, Elin; Mårtensson, Jerker; Börje, Anna

    2012-01-01

    Octocrylene is an organic UV filter, commonly used in sunscreens and cosmetics, which can give rise to both contact and photocontact allergy. Our aim was to investigate octocrylene's interaction with amino acid analogs in the presence of UV radiation to better understand the reason for octocrylene's photoallergenic capacity. The amino acid analogs were photolysed in presence and absence of octocrylene for 1 h in cyclohexane. The rate of degradation was considerably slower for all amino acid analogs when octocrylene was present in the mixture. Benzylamine, the lysine analog, did react with octocrylene during the photolysis and the corresponding amide was formed in an acylation reaction. By varying the benzylamine concentration and keeping the octocrylene concentration fixed the reaction rate was shown to be independent of the amine concentration. The same type of acylation reaction took place when octocrylene alone was photolysed in ethanol in which the ethyl ester was formed from octocrylene and ethanol. Our results suggest that octocrylene's ability to cause photocontact allergy could be due to its photoinduced reactivity toward primary amines and alcohols. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  1. Protective Role of Intracellular Melatonin Against Oxidative Stress and UV Radiation in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Ricardo Bisquert

    2018-02-01

    Full Text Available Melatonin (Mel is considered a potent natural antioxidant molecule given its free-radical scavenging ability. Its origin is traced back to the origin of aerobic life as early defense against oxidative stress and radiation. More complex signaling functions have been attributed to Mel as a result of evolution in different biological kingdoms, which comprise gene expression modulation, enzyme activity, and mitochondrial homeostasis regulation processes, among others. Since Mel production has been recently reported in wine yeast, we tested the protective effect of Mel on Saccharomyces cerevisiae against oxidative stress and UV light. As the optimal conditions for S. cerevisiae to synthesize Mel are still unknown, we developed an intracellular Mel-charging method to test its effect against stresses. To assess Mel’s ability to protect S. cerevisiae from both stresses, we ran growth tests in liquid media and viability assays by colony count after Mel treatment, followed by stress. We also analyzed gene expression by qPCR on a selection of genes involved in stress protection in response to Mel treatment under oxidative stress and UV radiation. The viability in the Mel-treated cells after H2O2 stress was up to 35% greater than for the untreated controls, while stress amelioration reached 40% for UVC light (254 nm. Mel-treated cells showed a significant shortened lag phase compared to the control cells under the stress and normal growth conditions. The gene expression analysis showed that Mel significantly modulated gene expression in the unstressed cells in the exponential growth phase, and also during various stress treatments.

  2. UV radiation is the primary factor driving the variation in leaf phenolics across Chinese grasslands.

    Science.gov (United States)

    Chen, Litong; Niu, Kechang; Wu, Yi; Geng, Yan; Mi, Zhaorong; Flynn, Dan Fb; He, Jin-Sheng

    2013-11-01

    Due to the role leaf phenolics in defending against ultraviolet B (UVB) under previously controlled conditions, we hypothesize that ultraviolet radiation (UVR) could be a primary factor driving the variation in leaf phenolics in plants over a large geographic scale. We measured leaf total phenolics, ultraviolet-absorbing compounds (UVAC), and corresponding leaf N, P, and specific leaf area (SLA) in 151 common species. These species were from 84 sites across the Tibetan Plateau and Inner Mongolian grasslands of China with contrasting UVR (354 vs. 161 mW/cm(2) on average). Overall, leaf phenolics and UVAC were all significantly higher on the Tibetan Plateau than in the Inner Mongolian grasslands, independent of phylogenetic relationships between species. Regression analyses showed that the variation in leaf phenolics was strongly affected by climatic factors, particularly UVR, and soil attributes across all sites. Structural equation modeling (SEM) identified the primary role of UVR in determining leaf phenolic concentrations, after accounting for colinearities with altitude, climatic, and edaphic factors. In addition, phenolics correlated positively with UVAC and SLA, and negatively with leaf N and N: P. These relationships were steeper in the lower-elevation Inner Mongolian than on the Tibetan Plateau grasslands. Our data support that the variation in leaf phenolics is controlled mainly by UV radiation, implying high leaf phenolics facilitates the adaptation of plants to strong irradiation via its UV-screening and/or antioxidation functions, particularly on the Tibetan Plateau. Importantly, our results also suggest that leaf phenolics may influence on vegetation attributes and indirectly affect ecosystem processes by covarying with leaf functional traits.

  3. Combined effects of O3 and UV radiation on secondary metabolites and endogenous hormones of soybean leaves.

    Directory of Open Access Journals (Sweden)

    Bing Mao

    Full Text Available Enhanced ultraviolet radiation (UV and elevated tropospheric ozone (O3 may individually cause reductions in the growth and productivity of important agricultural crops. However, research regarding their combined effects on important agricultural crops is still scarce, especially on changes in secondary metabolites and endogenous hormones, which are important protective substances and signal components that control plant responses to environment stresses. In this study, using an experimental setup of open top chambers, we monitored the responses of seed yield per plant, leaf secondary metabolites and leaf endogenous hormones under the stress of elevated O3 and enhanced UV radiation individually, as well as their combined stress. The results indicated that elevated O3 (110 ± 10 nmol mol-1 for 8 hours per day and enhanced UV radiation (1.73 kJ h-1 m-2 significantly decreased seed yield per plant. Concentrations of rutin, queretin and total flavonoids were significantly increased under the elevated O3 treatment or the enhanced UV radiation treatment or the combination treatment at flowering and podding stages, and concentrations of rutin, queretin and total flavonoids showed significant correlations with seed yield per plant. Concentrations of ABA and IAA decreased under the three treatments. There was a significant positive correlation between the ABA concentration and seed yield and a negative correlation between the IAA concentration and seed yield. We concluded that the combined stress of elevated O3 and UV radiation significantly decreased seed yield per plant. Yield reduction was associated with changes in the concentrations of flavonoids, ABA and IAA in soybean leaves. The effects of the combined O3 and UV stress were always greater than those of the individual stresses alone.

  4. PHOTODEGRADATION OF ALIZARIN S DYE USING TiO2-ZEOLITE AND UV RADIATION

    Directory of Open Access Journals (Sweden)

    Karna Wijaya

    2010-06-01

    Full Text Available An investigation of Alizarin S photodegradation using TiO2-zeolite and UV radiation was performed. TiO2-zeolite was prepared by dispersing oligocations of titanium into suspension of zeolite. The suspension was stirred and then filtered to separate the solid phase from the filtrate. the solid phase was calcined by microwave oven at 800 Watt for 5 minutes to convert the oligocations into its oxide forms. The calcined product and unmodified zeolite were characterized using x-ray diffractometry, FT-IR spectrophotometry, X-ray fluorescence and gas sorption analysis methods to determine their physicochemical properties. Photocatalytic activity of TiO2-zeolite was tested on Alizarin S solution using following method: 50 mg of zeolite was dispersed into 25 mL of 10-4 M Alizarin S. The dispersion was irradiated using 365 nm UV light at room temperature on various irradiation times, i.e. 10, 20, 30, 40 and 60 minutes. At certain irradiation time, the dispersion was filtered and the filtrate was then analyzed its concentration using UV-Vis spectrophotometry method. Characterization results exhibited that the formation of TiO2 on internal as well as external surfaces of zeolite could not be detected  with x-ray diffractometry and FT-IR spectrophotometry, however determination of titanium using x-ray fluorescence analysis on the calcined product showed that the concentration of titanium was much higher than zeolite (0.22% on zeolite and 12.08% on TiO2-zeolite. Gas sorption analysis result indicated that the the calcination  resulted in the increase of specific surface area (16,31 m2/g on zeolite and 100.96 m2/g on TiO2-zeolite as well as total pore volume of calcined product (13.34 mL/Å/g on zeolite and 57.54 mL/Å/g on TiO2-zeolite. The result of photocatalytic activitiy study showed that ca 99 % of Alizarin S was degraded by TiO2-zeolite after UV irradiation for 60 min.   Keywords: TiO2-zeolite, photocatalytic, Alizarin S.

  5. UV radiation elevates arylalkylamine N-acetyltransferase activity and melatonin content in the two-spotted spider mite, Tetranychus urticae.

    Science.gov (United States)

    Suzuki, Takeshi; Takashima, Takuya; Izawa, Norimitsu; Watanabe, Masakatsu; Takeda, Makio

    2008-07-01

    Ultraviolet (UV) radiation produces reactive oxygen species (ROS) in mammals, where melatonin plays the role of a ROS scavenger. The melatonin synthetic enzyme arylalkylamine N-acetyltransferase (NAT) is a significant element in a possible ROS removal system. Changes in NAT activity and melatonin content were determined in the two-spotted spider mite Tetranychus urticae by irradiating it with monochromatic light using the Okazaki Large Spectrograph at the National Institute for Basic Biology, Okazaki, Japan. The NAT activity and melatonin content were suppressed by blue light (450nm). No effects of red light (650nm) on the NAT activity and melatonin content were observed. UV radiation had intensity-dependent dual effects on the NAT activity and melatonin content. In the UV-B (300nm) treatment, the NAT activity and melatonin content were suppressed at the intensity below 1micromolm(-2)s(-1) but elevated when the intensity was as high as 10micromolm(-2)s(-1). In the UV-A (350nm) treatment, the melatonin content was elevated when the intensity was as high as 10micromolm(-2)s(-1), though the NAT activity and melatonin content were suppressed at the intensity below 10 and 1micromolm(-2)s(-1), respectively. Elevation of the NAT activity and melatonin content by high intensity UV irradiation may indicate that the UV signals initiate melatonin synthesis for ROS removal in mites.

  6. Visible laser and UV-A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant.

    Science.gov (United States)

    Nandakumar, Kanavillil; Keeler, Werden; Schraft, Heidi; Leung, Kam T

    2006-07-05

    The role of stationary phase sigma factor gene (rpoS) in the stress response of Moraxella strain when exposed to radiation was determined by comparing the stress responses of the wild-type (WT) and its rpoS knockout (KO) mutant. The rpoS was turned on by starving the WT cultures for 24 h in minimal salt medium. Under non-starved condition, both WT and KO planktonic Moraxella cells showed an increase in mortality with the increase in duration of irradiation. In the planktonic non-starved Moraxella, for the power intensity tested, UV radiation caused a substantially higher mortality rate than did by the visible laser light (the mortality rate observed for 15-min laser radiation was 53.4 +/- 10.5 and 48.7 +/- 8.9 for WT and KO, respectively, and 97.6 +/- 0 and 98.5 +/- 0 for 25 s of UV irradiation in WT and KO, respectively). However, the mortality rate decreased significantly in the starved WT when exposed to these two radiations. In comparison, rpoS protected the WT against the visible laser light more effectively than it did for the UV radiation. The WT and KO strains of Moraxella formed distinctly different types of biofilms on stainless steel coupons. The KO strain formed a denser biofilm than did the WT. Visible laser light removed biofilms from the surfaces more effectively than did the UV. This was true when comparing the mortality of bacteria in the biofilms as well. The inability of UV radiation to penetrate biofilms due to greater rates of surface absorption is considered to be the major reason for the weaker removal of biofilms in comparison to that of the visible laser light. This result suggests that high power visible laser light might be an effective tool for the removal of biofilms. (c) 2006 Wiley Periodicals, Inc.

  7. Rise and Fall: Poly(phenyl vinyl ketone) Photopolymerization and Photodegradation under Visible and UV Radiation.

    Science.gov (United States)

    Reeves, Jennifer A; Allegrezza, Michael L; Konkolewicz, Dominik

    2017-07-01

    Vinyl ketone polymers, including phenyl vinyl ketone (PVK), are an important class of polymers due to their ability to degrade upon irradiation with ultraviolet light which makes them useful for a variety of applications. However, traditional radical methods for synthesizing PVK polymers give rise to poor control or are unable to produce block copolymers. This work uses reversible addition-fragmentation chain transfer polymerization (RAFT) and photochemistry to polymerize PVK. When visible blue radiation of 440 ± 10 nm is used as the light source for the photopolymerization, rapid polymerization and well-defined polymers are created. This RAFT method uses PVK as both monomer and radical initiator, exciting the PVK mono-mer by 440 ± 10 nm irradiation to avoid the use of an additional radical initiator. Once the poly-mer is synthesized, it is stable against degradation by blue light (440 ± 10 nm), but upon exposure to ultraviolet (UV) radiation (310 ± 20 nm) significant decrease in molecular weight is observed. The degradation is observed for all poly(PVK) materials synthesized. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Protein deposition on field-emitter tips and its removal by UV radiation

    Science.gov (United States)

    Panitz, J. A.; Giaever, I.

    1980-07-01

    Protein deposition on field-emitter tips has been examined using Transmission Electron Microscopy to view the protein coated tip profile. A single layer of adsorbed protein is barely if at all detectable, but double and triple layers produced by the immunologic reaction can be directly observed. As a result, the thickness and morphology of antigen-antibody layers has been directly observed for the first time. Tips exposed first to Bovine Serum Albumin (BSA) and then to anti-BSA rabbit serum are covered with a reasonably uniform, double protein layer ≈130 Å thick. This layer can be built-up to a triple layer ≈275 Å thick by additional exposure to anti-rabbit IgG goat serum. Surface tension forces during the drying process which follows protein deposition appear to affect the thickness and morphology of the protein layers. The oxidation and subsequent change in the morphology of a protein layer exposed to ultraviolet radiation has also been observed using TEM. The destruction of a triple protein layer at a rate of ≈0.5 Å/s is observed for tungsten tips exposed to ≈6 W of UV radiation from a high-pressure mercury arc in laboratory ambient. These results are compared to those obtained from a simple, visual test for protein layer adsorption in which submonolayer coverages of protein can be detected with the unaided eye.

  9. Effect of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Rupiasih, N. Nyoman, E-mail: rupiasih@gmail.com [Department of Physics, Udayana University, Bali (Indonesia); Vidyasagar, Pandit B., E-mail: prof-pbv@yahoo.com [Biophysics Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

    2016-03-11

    An investigation of the effects of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings has been done. The UV-C irradiation periods of exposure were 30, 60, 90, 120 and 180 minutes. The hypergravity used were 1000 g, 2000 g and 2500 g. The combination treatment is UV-C irradiation for 180 min followed by each hypergravity. The results showed that irradiation of UV-C on wheat seeds have stimulated the seed germination, but hypergravity and combination treatments on wheat seeds have inhibited the seed germination. Those treatments gave negative effects to growth rate, the content of chlorophyll a, b and total chlorophyll of wheat seedlings.

  10. Increasing UV-B radiation at the earth's surface and potential effects on aqueous mercury cycling and toxicity.

    Science.gov (United States)

    Bonzongo, Jean Claude J; Donkor, Augustine K

    2003-09-01

    In the past two decades, a great deal of attention has been paid to the environmental fate of mercury (Hg), and this is exemplified by the growing number of international conferences devoted uniquely to Hg cycling and its impacts on ecosystem functions and life. This interest in the biogeochemistry of Hg has resulted in a significant improvement of our understanding of its impact on the environment and human health. However, both past and current research, have been primarily oriented toward the study of direct impact of anthropogenic activities on Hg cycling. Besides a few indirect effects such as the increase in Hg methylation observed in acid-rain impacted aquatic systems or the reported enhanced Hg bioaccumulation in newly flooded water reservoirs; changes in Hg transformations/fluxes that may be related to global change have received little attention. A case in point is the depletion of stratospheric ozone and the resulting increase in solar UV-radiation reaching the Earth. This review and critical discussion suggest that increasing UV-B radiation at earth's surface could have a significant and complex impact on Hg cycling including effects on Hg volatilization (photo-reduction), solubilization (photo-oxidation), methyl-Hg demethylation, and Hg methylation. Therefore, this paper is written to provoke discussions, and more importantly, to stimulate research on potential impacts of incoming solar UV-radiation on global Hg fluxes and any toxicity aspects of Hg that may become exacerbated by UV-radiation.

  11. Environmental effects of ozone depletion, UV radiation and interactions with climate change: UNEP Environmental Effects Assessment Panel, update 2017

    Science.gov (United States)

    The Environmental Effects Assessment Panel (EEAP) is one of three Panels of experts that inform the Parties to the Montreal Protocol. The EEAP focuses on the effects of UV radiation on human health, terrestrial and aquatic ecosystems, air quality, and materials, as well as on the...

  12. Electron Spin Resonance of Single Crystals of Cystine Dihydrochloride Irradiated with Monochromatic UV Radiation at Various Wavelenghts

    DEFF Research Database (Denmark)

    Lund-Thomsen, E.; Nielsen, S. O.

    1972-01-01

    Single crystals of cystine dihydrochloride were irradiated at room temperature with monochromatic uv radiation. The optical bandwidth was about 20 Å for each wavelength used. Essentially two ESR centers were observed, the relative yield being approximately 1. One center is identified as the RS ra...

  13. Mechanism of the immobilization of surfactants on polymeric surfaces by means of an argon plasma treatment: Influence of UV radiation

    NARCIS (Netherlands)

    Lens, J.P.; Spaay, B.; Terlingen, J.G.A.; Engbers, G.H.M.; Feijen, Jan

    1999-01-01

    The mechanism of the immobilization of the surfactant sodium 10-undecenoate (C11(:)) on poly(ethylene) (PE) by means of an argon plasma treatment has been investigated. In particular, the influence of the vacuum ultraviolet (UV) radiation emitted by the argon plasma on the immobilization was

  14. Impact of UV-radiation on viability, photosynthetic characteristics and DNA of brown algal zoospores : implications for depth zonation

    NARCIS (Netherlands)

    Wiencke, C; Gomez, [No Value; Pakker, H; Flores-Moya, A; Altamirano, M; Hanelt, D; Bischof, K; Figueroa, FL

    2000-01-01

    Measurements of photosynthesis, germination capacity and assessment of DNA damage were carried out in the laboratory to determine the effect of different conditions of ultraviolet (UV) and photosynthetically active radiation (PAR) on zoospores of various large brown algae collected on Spitsbergen

  15. Deleterious effects of UV-B radiation on herbivorous spider mites: they can avoid it by remaining on lower leaf surfaces.

    Science.gov (United States)

    Ohtsuka, Keiko; Osakabe, Masahiro M H

    2009-06-01

    The herbivorous spider mite Tetranychus urticae usually remains on the lower leaf surfaces of its host plants. Although terrestrial animals are generally thought to be well protected from damage because of UV radiation, insect herbivory frequently increases when solar UV-B (280-315 nm) radiation is attenuated. As UV transmission through leaves is generally low because of the accumulation of compounds that act as selective sunscreens (e.g., phenolics), we hypothesized that T. urticae avoids solar UV-B radiation by staying on lower leaf surfaces. We examined whether artificial UV irradiation and solar UV affected the survival and reproduction of T. urticae and whether staying on lower leaf surfaces was beneficial to their performance under ambient UV radiation. We found that T. urticae was not well protected from UV-B radiation, because artificial UV-B irradiation strongly decreased survivorship and egg production. More importantly; compulsory solar UV irradiation treatments also had lethal effects on T. urticae, whereas the mites could avoid them if they remained on the lower leaf surfaces of their host plants. These results showed that access to habitats protected from sunlight, such as lower leaf surfaces, is likely essential for T. urticae survival under ambient UV-B radiation. The lethal effects of solar UV radiation may also affect the population dynamics of spider mites, and habitat (resource) limitation may increase the probability of interspecific interactions, such as competition and predation. In turn, the occurrence of these interactions in sheltered areas may be associated with observed increases in herbivory under conditions of solar UV-B-attenuation.

  16. A ΔdinB mutation that sensitizes Escherichia coli to the lethal effects of UV- and X-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Mei-Chong W.; Franco, Magdalena; Vargas, Doris M. [Department of Biological Sciences, San Jose State University, San Jose, CA 95192 (United States); Hudman, Deborah A. [Department of Microbiology and Immunology, A.T. Still University, Kirksville College of Osteopathic Medicine, Kirksville, MO 63501 (United States); White, Steven J. [Department of Biological Sciences, San Jose State University, San Jose, CA 95192 (United States); Fowler, Robert G., E-mail: rfowler@sjsu.edu [Department of Biological Sciences, San Jose State University, San Jose, CA 95192 (United States); Sargentini, Neil J. [Department of Microbiology and Immunology, A.T. Still University, Kirksville College of Osteopathic Medicine, Kirksville, MO 63501 (United States)

    2014-05-15

    Highlights: • We describe Δ(dinB-yafN)883(::kan), a novel dinB allele, referred to as ΔdinB883, a deletion that sensitizes E. coli cells to UV irradiation. • This UV radiation sensitivity is most acute in the early logarithmic phase of culture growth. • This UV radiation sensitivity is completely dependent upon a functional umuDC operon. • Sequencing reveals ΔdinB883 retains the proximal 161 nucleotides, i.e., 54 amino acids, of the wild-type sequence. • The ΔdinB883 mutant is hypothesized to produce a peptide of 83 amino acids, DinB883, that compromises UmuDC function. - Abstract: The DinB (PolIV) protein of Escherichia coli participates in several cellular functions. We investigated a dinB mutation, Δ(dinB-yafN)883(::kan) [referred to as ΔdinB883], which strongly sensitized E. coli cells to both UV- and X-radiation killing. Earlier reports indicated dinB mutations had no obvious effect on UV radiation sensitivity which we confirmed by showing that normal UV radiation sensitivity is conferred by the ΔdinB749 allele. Compared to a wild-type strain, the ΔdinB883 mutant was most sensitive (160-fold) in early to mid-logarithmic growth phase and much less sensitive (twofold) in late log or stationary phases, thus showing a growth phase-dependence for UV radiation sensitivity. This sensitizing effect of ΔdinB883 is assumed to be completely dependent upon the presence of UmuDC protein; since the ΔdinB883 mutation did not sensitize the ΔumuDC strain to UV radiation killing throughout log phase and early stationary phase growth. The DNA damage checkpoint activity of UmuDC was clearly affected by ΔdinB883 as shown by testing a umuC104 ΔdinB883 double-mutant. The sensitivities of the ΔumuDC strain and the ΔdinB883 ΔumuDC double-mutant strain were significantly greater than for the ΔdinB883 strain, suggesting that the ΔdinB883 allele only partially suppresses UmuDC activity. The ΔdinB883 mutation partially sensitized (fivefold) uvrA and uvr

  17. Association of UV radiation with multiple sclerosis prevalence and sex ratio in France.

    Science.gov (United States)

    Orton, S-M; Wald, L; Confavreux, C; Vukusic, S; Krohn, J P; Ramagopalan, S V; Herrera, B M; Sadovnick, A D; Ebers, G C

    2011-02-01

    French farmers and their families constitute an informative population to study multiple sclerosis (MS) prevalence and related epidemiology. We carried out an ecological study to evaluate the association of MS prevalence and ultraviolet (UV) radiation, a candidate climatologic risk factor. Mean annual and winter (December-March) UVB irradiation values were systematically compared to MS prevalence rates in corresponding regions of France. UVB data were obtained from the solar radiation database (SoDa) service and prevalence rates from previously published data on 2,667 MS cases registered with the national farmer health insurance system, Mutualité Sociale Agricole (MSA). Pearson correlation was used to examine the relationship of annual and winter UVB values with MS prevalence. Male and female prevalence were also analyzed separately. Linear regression was used to test for interaction of annual and winter UVB with sex in predicting MS prevalence. There was a strong association between MS prevalence and annual mean UVB irradiation (r = -0.80, p < 0.001) and average winter UVB (r = -0.87, p < 0.001). Both female (r = -0.76, p < 0.001) and male (r = -0.46, p = 0.032) prevalence rates were correlated with annual UVB. Regression modeling showed that the effect of UVB on prevalence rates differed by sex; the interaction effect was significant for both annual UVB (p = 0.003) and winter UVB (p = 0.002). The findings suggest that regional UVB radiation is predictive of corresponding MS prevalence rates and supports the hypothesis that sunlight exposure influences MS risk. The evidence also supports a potential role for gender-specific effects of UVB exposure.

  18. DNA damage and photosynthesis in Antarctic and Arctic Sanionia uncinata (Hedw.) Loeske under ambient and enhanced levels of UV-B radiation

    NARCIS (Netherlands)

    Lud, D.; Moerdijk-Poortvliet, T.C.W.; Van de Poll, W.H.; Buma, A.G.J.; Huiskes, A.H.L.

    2002-01-01

    The response of the bipolar moss Sanionia uncinata (Hedw.) Loeske to ambient and enhanced UV-B radiation was investigated at an Antarctic (Léonie Island, 67°35' S, 68°20' W) and an Arctic (Ny-Alesund, 78°55' N, 11°56' E) site, which differed in ambient UV-B radiation (UV-BR: 280-320 nm) levels. The

  19. Identification of Native Bacteria of the Candelaria and Tatacoa Semiarid Zone, Capable of Withstanding a Mars UV Radiation Simulation

    Science.gov (United States)

    Mendez, Y.; Vives, M.

    2017-07-01

    This work is the first study to describe native bacteria from the semi-arid areas in Candelaria and Tatacoa in Colombia, able to withstand a simulation of UV radiation, in order to draw an analogy with microbial growth on the surface of Mars. Sampling was carried out in the areas mentioned taking 50 samples of sediment divided into 25 samples of surface and 25 deep samples. As soon as the samples were transferred, they were subjected to a test of UV radiation in an atmospheric simulation chamber designed for the experiment, for periods of 1, 6 and 12 hours of exposure. Microbiological analysis as a method of plate dilution and isolation were performed using the modified AIS growth medium, macroscopic and microscopic description of morphotypes, biochemical identification of the morphotypes found, extraction of the feasible mycelium, DNA extraction and amplification of the gene 16 S by PCR. 13 morphotypes of bacteria resistant to UV radiation were found, mostly compatible with the gender of Streptomyces. One of the morphotypes found resisted 12 hours exposure. Molecular analyzes did not produce any results, because it was not possible to amplify the 16S by PCR, this may be due to that the exposure to UV radiation can degrade the DNA in existence, a affecting the results. The finding of native bacteria capable of withstanding conditions UV radiation can give us an approximation of microbial growth, mechanisms of resistance and survival under extreme conditions such as those found on Mars, in order to develop biotechnological applications and establish planetary analogues to understand the origin and evolution of the universe.

  20. Increased exposure to UV-B radiation during early development leads to enhanced photoprotection and improved long-term performance in Lactuca sativa.

    Science.gov (United States)

    Wargent, Jason J; Elfadly, Eslam M; Moore, Jason P; Paul, Nigel D

    2011-08-01

    Plant responses to solar UV radiation are numerous and have often been considered from a perspective of negative outcomes for plant productivity. In this study, we used two experimental approaches consisting of: (1) field-based spectrally modifying filters in addition to (2) controlled indoor exposure to UV-B, to examine the effects of UV radiation on growth and photosynthetic performance of lettuce (Lactuca sativa L.) seedlings. Various aspects of growth were affected in plants grown under a UV-inclusive environment compared to a UV-depleted environment, including reductions in leaf expansion, increases in leaf thickness and the rate of net photosynthesis. After transplantation to a uniform field environment, lettuce plants initially propagated under the UV-inclusive environment exhibited higher harvestable yields than those from a UV-depleted environment. In controlled conditions, photosynthetic rates were higher in plants grown in the presence of UV-B radiation, and relative growth of plants pre-acclimatized to UV-B was also increased, in addition to higher maximum photochemical efficiency of photosystem II (PSII) (F(v) /F(m) ) following subsequent exposure to high photosynthetically active radiation (PAR) and temperature stress. Our findings are discussed within the context of sustainability in agriculture and the paradigm shift in photobiology which such beneficial responses to UV radiation could represent. © 2011 Blackwell Publishing Ltd.

  1. Economic burden analysis for UV radiation and vitamin D for colorectal cancer in the United States

    Science.gov (United States)

    Garland, Cedric F.; Mohr, Sharif B.; Grant, William B.; Holick, Michael F.

    2005-08-01

    Moderate exposure to sunlight is a key factor in maintaining adequate levels of vitamin D. Vitamin D sufficiency is associated with reduced incidence of many forms of cancer, osteoporotic fractures, multiple sclerosis, and other diseases. However, excessive ultraviolet radiation (UVR) exposure may be associated with melanoma and nonmelanoma skin cancer. An estimated 50,000-60,000 individuals die prematurely from cancer annually due to insufficient vitamin D in the US. The annual economic burden due to vitamin D insufficiency from inadequate exposure to solar ultraviolet B (UVB) or deficient oral intake is estimated at $46-65 billion, while that for excessive UVR exposure is $5-7 billion (1). Since excessive UVR exposure is not required for adequate vitamin D photosynthesis, increasing national guidelines for vitamin D intake and de-stigmatizing appropriate solar UVB exposure would substantially reduce medical care costs. This report describes an algorithm for estimating the annual number of dollars that could be saved and deaths from colorectal cancer that could be prevented by moderate daily exposure to sunlight or increased oral intake of vitamin D3. If the assumptions of this analysis are valid, moderate exposure to sunlight or adequate oral intake of vitamin D3 would prevent 10 deaths from colorectal cancer for every death from skin cancer that it might induce, and would save $11 billion per year. Reference: (1) Grant WB, Garland CF, Holick MF. Comparisons of estimated economic burdens due to insufficient solar ultraviolet (UV) irradiation or vitamin D and excess solar UV irradiation. Photochem Photobiol. In press.

  2. On the wavelength dependence of UV induced thymine photolesions: a synchrotron radiation circular dichroism study.

    Science.gov (United States)

    Madsen, Marlene Møller; Jones, Nykola C; Nielsen, Steen Brøndsted; Hoffmann, Søren Vrønning

    2016-11-09

    Solar mutagenesis via the formation of thymine dimer photoproducts is a primary cause of skin cancer. The aim of this study is to provide a direct method for following the development of photolesions in thymine single strands and to determine how the formation of these photoproducts depends on the excitation wavelength in the ultraviolet (UV) between 210 nm and 325 nm. Experiments were performed both with a 20 Hz pulsed, intense, tunable laser as well as UV lamps (at 254 nm and 302 nm), but we find that only the dose matters at these wavelengths for the yield of photoproducts. Hence in both cases the lesion process is due to one-photon absorption. The formation and yields of the photoproducts as the irradiation dose is increased is followed through measurement of synchrotron radiation circular dichroism (SRCD) spectra. A principal component analysis (PCA) of the SRCD data yields CD signatures for each of the resulting photoproducts and reveals a strong irradiation wavelength dependence upon which products are formed; cyclobutane pyrimidine dimers (CPDs) are formed primarily at higher irradiation wavelengths (from 250 to 300 nm); the 6,4 pyrimidine-pyrimidone photoadduct (64PP) is formed in the range 210 to 285 nm, with a higher rate of formation in the lower part of that range, while in the very lowest irradiation wavelength range (210 to 240 nm) we find thymidine monophosphate (dTMP), which indicates cleavage of the DNA backbone. Our work demonstrates the strength of SRCD spectroscopy compared to ordinary absorption spectroscopy, as the latter is not sufficient to obtain fingerprints of the thymine photoproducts.

  3. Benzophenone 1 induced photogenotoxicity and apoptosis via release of cytochrome c and Smac/DIABLO at environmental UV radiation.

    Science.gov (United States)

    Amar, Saroj Kumar; Goyal, Shruti; Dubey, Divya; Srivastav, Ajeet K; Chopra, Deepti; Singh, Jyoti; Shankar, Jai; Chaturvedi, Rajnish K; Ray, Ratan Singh

    2015-12-15

    Solar UV radiation is main factor of photocarcinogenesis, photoageing, and phototoxicity; thus, protection from UV radiation is major concern. Sunscreens containing UV filters are suggested as sun safe practices, but safety of UV filters remains in controversies. Benzophenone-1 (BP1) is commonly used in sunscreens as UV blocker. We assessed the photogenotoxicity and apoptotic parameters in human keratinocytes (HaCaT cells) by western blot, immunocytochemistry, flowcytometry, comet assay and TEM imaging. Our results exposed that BP1 photosensitized and generated intracellular ROS (2.02 folds) under sunlight/UVR. Decrease in cell viability was recorded as 80.06%, 60.98% and 56.24% under sunlight, UVA and UVB, respectively. Genotoxic potential of BP1 was confirmed through photomicronuclei and CPDs formation. BP1 enhanced lipid peroxidation and leakage of LDH enzyme (61.7%). Apoptotic cells were detected by AnnexinV/PI staining and sub G1 population of cell cycle. BP1 induced up regulation of apoptotic proteins Bax/Bcl2 ratio, Apaf-1, cytochrome c, Smac/DIABLO and cleaved caspase 3 was noticed. Down regulation of pro caspase 3 was inhibited by Z-VAD-fmk (inhibitor of caspase). Thus, study established the involvement of BP1 in photogenotoxicity and apoptosis via release of cytochrome c and Smac/DIABLO. These findings suggest sunscreen user to avoid BP1 in cosmetics preparation for its topical application. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Enhancement of root growth and nitrogen fixation in Trigonella by UV-exclusion from solar radiation.

    Science.gov (United States)

    Sharma, Sonika; Guruprasad, K N

    2012-12-01

    A field experiment was conducted to study the impact of solar UV on root growth and nitrogen fixation in Trigonella foenum-graecum. Plants were grown in iron mesh cages covered with polyester filters that could specifically cut off UV-B (280-315 nm) or UV-A + B (280-400 nm) part of the solar spectrum. The control plants were grown under a polythene filter transmissible to UV. Root biomass, number of nodules and nodule fresh weight were enhanced after exclusion of solar UV. Nitrogenase activity was significantly enhanced by 120% and 80% in the UV-B and UV-A + B excluded plants respectively. Along with nitrogenase there was concomitant increase in leghemoglobin and hemechrome content in the nodules after exclusion of solar UV. These components of sunlight limits nitrogen fixation and their elimination can enhance nitrogen fixation with agricultural advantages like reduction in the use of fertilizers. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. 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

    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...

  6. Proteome readjustments in the apoplastic space of Arabidopsis thaliana ggt1 mutant leaves exposed to UV-B radiation

    Directory of Open Access Journals (Sweden)

    Anna Rita eTrentin

    2015-03-01

    Full Text Available Ultraviolet-B radiation acts as an environmental stimulus, but in high doses it has detrimental effects on plant metabolism. Plasma membranes represent a major target for ROS generated by this harmful radiation. Oxidative reactions occurring in the apoplastic space are counteracted by antioxidative systems mainly involving ascorbate and, to some extent, glutathione. The occurrence of the latter and its exact role in the extracellular space are not well documented, however. In Arabidopsis thaliana, the gamma-glutamyl transferase isoform GGT1 bound to the cell wall takes part in the so-called gamma-glutamyl cycle for extracellular glutathione degradation and recovery, and may be implicated in redox sensing and balance.In this work, oxidative conditions were imposed with UV-B and studied in redox altered ggt1 mutants. The response of ggt1 knockout Arabidopsis leaves to UV-B radiation was assessed by investigating changes in extracellular glutathione and ascorbate content and their redox state, and in apoplastic protein composition. Our results show that, on UV-B exposure, soluble antioxidants respond to the oxidative conditions in both genotypes. Rearrangements occur in their apoplastic protein composition, suggesting an involvement of H2O2, which may ultimately act as a signal. Other important changes relating to hormonal effects, cell wall remodeling, and redox activities are discussed. We argue that oxidative stress conditions imposed by UV-B and disruption of the gamma-glutamyl cycle result in similar stress-induced responses, to some degree at least.

  7. Climatology of Ultra Violet(UV) Irradiance at the Surface of the Earth as Measured by the Belgian UV Radiation Monitoring Network

    Science.gov (United States)

    Pandey, Praveen; Gillotay, Didier; Depiesse, Cedric

    2016-08-01

    In this paper we describe the network of ground-based ultraviolet (UV) radiation monitoring stations in Belgium. The evolution of the entire network, together with the details of measuring instruments is given. The observed cumulative irradiations -UVB, UVA and total solar irradiation (TSI)- over the course of measurement for three stations -a northern (Ostende), central (Uccle) and a southern (Redu)- are shown. The longest series of measurement shown in this study is at Uccle, Brussels, from 1995 till 2014. Thus, the variation of the UV index, together with the variation of irradiations during summer and winter months at Uccle are shown as a part of this climatological study. The trend of UVB irradiance over the above mentioned three stations is shown. This UVB trend is studied in conjunction with the long-term satellite-based total column ozone value over Belgium, which shows two distinct trends marked by a change point. The total column ozone trend following the change point is positive. It is also seen that the UVB trend is positive for the urban/sub-urban sites: Uccle and Redu. Whereas the UVB trend at Ostende, which is a coastal site, is not positive. A possible explanation of this relation between total column ozone and UVB trend could be associated with aerosols, which is shown in this paper by means of a radiative transfer model based study -as a part of a preliminary investigation. It is seen that the UVI is influenced by the type of aerosols.

  8. Dissolved organic carbon ameliorates the effects of UV radiation on a freshwater fish

    Energy Technology Data Exchange (ETDEWEB)

    Manek, Aditya K., E-mail: aditya.manek@usask.ca [Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2 SK (Canada); Ferrari, Maud C.O. [Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, S7N 5B4 SK (Canada); Chivers, Douglas P.; Niyogi, Som [Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2 SK (Canada)

    2014-08-15

    Anthropogenic activities over the past several decades have depleted stratospheric ozone, resulting in a global increase in ultraviolet radiation (UVR). Much of the negative effects of UVR in aquatic systems is minimized by dissolved organic carbon (DOC) which is known to attenuate UVR across the water column. The skin of many fishes contains large epidermal club cells (ECCs) that are known to play a role in innate immune responses and also release chemical alarm cues that warn other fishes of danger. This study investigated the effects of in vivo UVR exposure to fathead minnows (Pimephales promelas), under the influence of two sources of DOC: Sigma Aldrich humic acid, a coal based commercial source of DOC and Luther Marsh natural organic matter, a terrigenous source of DOC. Specifically, we examined ECC investment and physiological stress responses and found that fish exposed to high UVR, in the presence of either source of DOC, had higher ECC investment than fish exposed to high UVR only. Similarly, exposure to high UVR under either source of DOC, reduced cortisol levels relative to that in the high UVR only treatment. This indicates that DOC protects fish from physiological stress associated with UVR exposure and helps maintain production of ECC under conditions of UVR exposure. - Highlights: • We examined the combined effect of UV radiation and Dissolved Organic Carbon on fish. • Physiological stress response and epidermal club cell investment were measured. • Fish exposed to high UVR and DOC had higher ECC investment and reduced cortisol levels. • DOC plays a role in protecting fish from physiological stress and maintains ECC production.

  9. Effects of PAR and UV Radiation on the Structural and Functional Integrity of Phycocyanin, Phycoerythrin and Allophycocyanin Isolated from the Marine Cyanobacterium Lyngbya sp. A09DM.

    Science.gov (United States)

    Rastogi, Rajesh Prasad; Sonani, Ravi Raghav; Madamwar, Datta

    2015-01-01

    An in vitro analysis of the effects of photosynthetically active and ultraviolet radiations was executed to assess the photostability of biologically relevant pigments phycocyanin (PC), phycoerythrin (PE) and allophycocyanin (APC) isolated from Lyngbya sp. A09DM. Ultraviolet (UV) irradiances significantly affected the integrity of PC, PE and APC; however, PAR showed least effect. UV radiation affected the bilin chromophores covalently attached to phycobiliproteins (PBPs). Almost complete elimination of the chromophore bands associated with α- and β-subunit of PE and APC occurred after 4 h of UV-B exposure. After 5 h of UV-B exposure, the content of PC, PE and APC decreased by 51.65%, 96.8% and 96.53%, respectively. Contrary to PAR and UV-A radiation, a severe decrease in fluorescence of all PBPs was observed under UV-B irradiation. The fluorescence activity of extracted PBP was gradually inhibited immediately after 15-30 min of UV-B exposure. In comparison to the PC, the fluorescence properties of PE and APC were severely lost under UV-B radiation. Moreover, the present study indicates that UV-B radiation can damage the structural and functional integrity of phycobiliproteins leading to the loss of their ecological and biological functions. © 2015 The American Society of Photobiology.

  10. The analysis of the correlations between NO2 column, O3 column and UV radiation at global level using space observations

    Science.gov (United States)

    Dimitrievici, Lucian; Constantin, Daniel-Eduard; Moraru, Luminita

    2017-01-01

    A well known relationship between nitrogen dioxide (NO2), ozone (O3) and ultra-violet radiation (UV) exists. In this work several correlations between NO2 column, O3 column, and UV radiation for several worldwide urban agglomerations or stations during 2004-2015 are presented. For the both NO2 and O3 columns we used the Ozone Monitoring Observations (OMI) instrument, which is a space sun-synchronous polar orbit space instrument. UV parameter has been determined using the clear-sky UV index which is the effective UV irradiance which reaches the surface of the Earth. The UV station data utilized satellite data acquired by SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) and GOME-2 (Global Ozone Monitoring Experiment) instruments. The time or local dependencies of the evolution of the NO2 column, O3 column and UV index above the selected cities or stations are analyzed and presented.

  11. Simulation of the Martian UV radiation climate and its effect on Deinococcus radiodurans

    Science.gov (United States)

    Pogoda de La Vega, U.; Rettberg, P.

    The question of putative life on Mars has been the topic of several studies Early works had to rely on the physical data that have been gained during the 1970s with the help of the Viking missions More recently several Mars-related missions have provided numerous and more precise data to establish a realistic simulation of the Martian climate Our focus is directed at the diurnal temperature variations and the atmospheric pressure and composition the so called thermo-physical conditions which are typical for the Martian mid- and low latitudes The resistance of terrestrial microorganisms under the thermo-physical conditions on Mars was studied for the understanding and assessment of potential life processes on Mars In order to accomplish a targeted search for life on other planets e g Mars it is necessary to know the limiting physical and chemical parameters of terrestrial life Therefore the polyextremophile bacterium Deinococcus radiodurans was chosen as test organism for these investigations For the simulation studies at the Planetary and Space Simulation Facilities PSI at DLR Cologne Germany conditions that are present during the southern summer at latitude of 60 r on Mars were applied We could simulate several environmental parameters of Mars vacuum low pressure anoxic atmosphere and diurnal cycles in temperature energy-rich UV radiation as well as shielding by different Martian soil analogue materials These parameters have been applied both single and in different combinations in laboratory experiments

  12. Rosmarinic acid, a photo-protective agent against UV and other ionizing radiations.

    Science.gov (United States)

    Sánchez-Campillo, M; Gabaldon, J A; Castillo, J; Benavente-García, O; Del Baño, M J; Alcaraz, M; Vicente, V; Alvarez, N; Lozano, J A

    2009-02-01

    Solar UV and other ionizing radiations cause a generation of reactive oxygen species, induce cellular DNA damage and alter skin homeostasis. The use of exogenous antioxidants is increasingly frequents, we attempt to demonstrate that a rosmarinic acid extract acts as photo-protector; both free radical scavenger as an inducer of the body's own endogenous defence mechanisms by regulating tyrosinase activity and stimulating melanin production. Malonyldialdehyde formation (TBARS) was delayed when RA was used. The protection factor was 3.24 times vs AA. TEAC value for RA was 1.6 times vs AA. The radioprotective-antimutagenic effects of RA were measure using the micronucleus test. The level of micronucleous for treatments before irradiation was: RA [14]

  13. Thermoluminescence response of previously heated NaCl : Eu crystals to UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mondragon-Galicia, G; Mendoza-Anaya, D [Instituto Nacional de Investigaciones Nucleares, Departmento TecnologIa de Materiales, Carretera Mexico-Toluca s/n La Marquesa, Ocoyoacac, Edo. de Mexico, C.P. 52750 (Mexico); Nicho-Diaz, M E [Centro de Investigacion en IngenierIa y Ciencias Aplicadas. Universidad Autonoma del Estado de Morelos, C.P. 62209, Cuernavaca, Morelos (Mexico); Garcia-Garcia, R; Reyes-Gasga, J [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000 Mexico, D.F. Mexico (Mexico)

    2008-02-21

    In this work we report the modification in the thermoluminescent (TL) response to ultraviolet (UV) radiation of Czochralski-grown NaCl : Eu crystals when they are pre-heated. The crystals were pre-heated at 273, 473, 573, 673, 773 and 873 K for 2 h in an inert atmosphere, observing the highest response in crystals pre-heated at 573 K and the lowest in crystals pre-heated at 473 K. To correlate the TL response with the thermal treatment and, in a certain way, with the microstructure developed in the crystals, they were observed with a low vacuum scanning electron microscope. At 373 K the crystals showed spherical precipitates of 100 nm size homogeneously distributed, whereas at 473 and 573 K, the crystals showed, besides spherical precipitates, wire-like precipitates from 1.0 to 7.0 {mu}m in length. The precipitates changed to a square 4 {mu}m in size at 673 K which diminished to 1.0 {mu}m in size in crystals heated at 773 and 873 K. Clearly the shape of the precipitates has an influence on the TL response of the NaCl : Eu crystals.

  14. Overview of the molecular defense systems used by sea urchin embryos to cope with UV radiation.

    Science.gov (United States)

    Bonaventura, Rosa; Matranga, Valeria

    2017-07-01

    The sea urchin embryo is a well-recognized developmental biology model and its use in toxicological studies has been widely appreciated. Many studies have focused on the evaluation of the effects of chemical stressors and their mixture in marine ecosystems using sea urchin embryos. These are well equipped with defense genes used to cope with chemical stressors. Recently, ultraviolet radiation (UVR), particularly UVB (280-315 nm), received more attention as a physical stressor. Mainly in the Polar Regions, but also at temperate latitudes, the penetration of UVB into the oceans increases as a consequence of the reduction of the Earth's ozone layer. In general, UVR induces oxidative stress in marine organisms affecting molecular targets such as DNA, proteins, and lipids. Depending on the UVR dose, developing sea urchin embryos show morphological perturbations affecting mainly the skeleton formation and patterning. Nevertheless, embryos are able to protect themselves against excessive UVR, using mechanisms acting at different levels: transcriptional, translational and post-translational. In this review, we recommend the sea urchin embryo as a suitable model for testing physical stressors such as UVR and summarize the mechanisms adopted to deal with UVR. Moreover, we review UV-induced apoptotic events and the combined effects of UVR and other stressors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. 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)

  16. The fluence rate determines the synergistic interaction of UV radiation and heat for mitotic recombination and cell inactivation in yeasts.

    Science.gov (United States)

    Kim, Jin Kyu; Komarova, Ludmila N; Zhurakovskaya, Galina P; Petin, Vladislav G

    2006-01-01

    The significance of the UV fluence rate for the synergistic interaction of UV light (254 nm) and heat was demonstrated for the frequency of mitotic recombination in a wild-type diploid yeast of Saccharomyces cerevisiae (strain T1) and for cell inactivation of two wild-type diploid yeast of S. cerevisiae (strains T1, XS800). It was shown for mitotic recombination that a decrease in the intensity of UV exposure results in the necessity of decreasing the temperature at which UV irradiation occurs to provide the same value of the synergistic enhancement ratio. For cell inactivation, there was a specific temperature maximizing the synergistic effect for any constant fluence rate and the temperature range, synergistically increasing the inactivation effect of UV radiation, should be shifted to lower temperatures with a decrease in the fluence rate. To interpret the results observed, a simple mathematical model of the synergistic interaction was applied. The model suggests that the synergistic interaction of UV light and hyperthermia is expected to result from some additional effective damages arising from the interaction of some sublesions induced by both agents. On the basis of data obtained, it was supposed that the synergistic interaction of these factors might take place at small intensities of UV light and temperatures existing in the biosphere. In other words, for a long duration of interaction, which is important for problems of UV light protection and health effects, one can expect a synergistic interaction of this factor with environmental heat or physiological temperatures and thereby an increase in their inactivating and genetic consequences.

  17. 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.

  18. A comparison of six different ballast water treatment systems based on UV radiation, electrochlorination and chlorine dioxide.

    Science.gov (United States)

    Stehouwer, Peter Paul; Buma, Anita; Peperzak, Louis

    2015-01-01

    The spread of aquatic invasive species through ballast water is a major ecological and economical threat. Because of this, the International Maritime Organization (IMO) set limits to the concentrations of organisms allowed in ballast water. To meet these limits, ballast water treatment systems (BWTSs) were developed. The main techniques used for ballast water treatment are ultraviolet (UV) radiation and electrochlorination (EC). In this study, phytoplankton regrowth after treatment was followed for six BWTSs. Natural plankton communities were treated and incubated for 20 days. Growth, photosystem II efficiency and species composition were followed. The three UV systems all showed similar patterns of decrease in phytoplankton concentrations followed by regrowth. The two EC and the chlorine dioxide systems showed comparable results. However, UV- and chlorine-based treatment systems showed significantly different responses. Overall, all BWTSs reduced phytoplankton concentrations to below the IMO limits, which represents a reduced risk of aquatic invasions through ballast water.

  19. The antibacterial activity of a microwave argon plasma jet at atmospheric pressure relies mainly on UV-C radiations

    Science.gov (United States)

    Judée, F.; Wattieaux, G.; Merbahi, N.; Mansour, M.; Castanié-Cornet, M. P.

    2014-10-01

    The main bactericidal sources produced by a microwave induced cold argon plasma jet in open air are identified and their relative proportion in the biocide efficiency of the jet is assessed on planktonic Gram-negative bacteria (wild-type strains and deletion mutants of Escherichia coli) diluted in water. In these conditions ultraviolet light (UV) most probably in the UV-C region of the electromagnetic spectrum, is responsible for 86.7 ± 3.2% of the observed bactericidal efficiency of the jet whereas hydrogen peroxide represents 9.9 ± 5.5% of it. The exposition level of the bacteria to UV-C radiations is estimated at 20 mJ cm-2 using a specific photodiode and the influence of the initial bacteria concentration on the apparent antibacterial efficiency of the jet is highlighted.

  20. Application of Satellite and Ground-based Data to Investigate the UV Radiative Effects of Australian Aerosols

    Science.gov (United States)

    Kalashnikova, Olga V.; Mills, Franklin P.; Eldering, Annmarie; Anderson, Don

    2007-01-01

    An understanding of the effect of aerosols on biologically- and photochemically-active UV radiation reaching the Earth's surface is important for many ongoing climate, biophysical, and air pollution studies. In particular, estimates of the UV characteristics of the most common Australian aerosols will be valuable inputs to UV Index forecasts, air quality studies, and assessments of the impact of regional environmental changes. By analyzing climatological distributions of Australian aerosols we have identified sites where co-located ground-based UV-B and ozone measurements were available during episodes of relatively high aerosol activity. Since at least June 2003, surface UV global irradiance spectra (285-450 nm) have been measured routinely at Darwin and Alice Springs in Australia by the Australian Bureau of Meteorology (BoM). Using colocated sunphotometer measurements at Darwin and Alice Springs, we identified several episodes of relatively high aerosol activity. Aerosol air mass types were analyzed from sunphotometer-derived angstrom parameter, MODIS fire maps and MISR aerosol property retrievals. To assess aerosol effects we compared the measured UV irradiances for aerosol-loaded and clear-sky conditions with each other and with irradiances simulated using the libRadtran radiative transfer model for aerosol-free conditions. We found that for otherwise similar atmospheric conditions, smoke aerosols over Darwin reduced the surface UV irradiance by as much as 40-50% at 290-300 nm and 20-25% at 320-400 nm near active fires (aerosol optical depth, AOD, at 500 nm approximately equal to 0.6). Downwind of fires, the smoke aerosols over Darwin reduced the surface irradiance by 15-25% at 290-300 nm and approximately 10% at 320-350 nm (AOD at 500 nm approximately equal to 0.2). The effect of smoke increased with decrease of wavel strongest in the UV-B. The aerosol attenuation factors calculated for the selected cases suggest smoke over Darwin has an effect on surface 340

  1. UV-B radiation arising from stratospheric ozone depletion influences the pigmentation of the Antarctic moss Andreaea regularis.

    Science.gov (United States)

    Newsham, K K

    2003-05-01

    Changes to the radiative environment arising from stratospheric ozone (O(3)) depletion and subsequent associations between these changes and the pigmentation of the moss Andreaea regularis were measured in late austral spring and early summer 1998 at Rothera Point on the western Antarctic Peninsula (67 degrees S, 68 degrees W). A strong relationship between O(3) column depth and the ratio of UV-B to PAR irradiance ( F(uv-b)/ F(par)) was recorded at ground level ( r(2)=92%, Pdepletion. The data derived from this study suggest that changes to the radiative environment associated with stratospheric O(3) depletion influence the pigmentation of A. regularis. As a corollary, flavonoids are shown to be present in tissues of A. regularis.

  2. Effect of proline on biochemical and molecular mechanisms in lettuce (Lactuca sativa L.) exposed to UV-B radiation.

    Science.gov (United States)

    Aksakal, Ozkan; Tabay, Dilruba; Esringu, Aslıhan; Icoglu Aksakal, Feyza; Esim, Nevzat

    2017-02-15

    The purpose of the present study was to evaluate the role of proline (Pro) in relieving UV-B radiation-induced oxidative stress in lettuce. Lettuce seedlings were exposed to 3.3 W m -2 UV-B radiation for 12 h after pre-treatment sprayed with 20 mM Pro. The data for malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), endogenous Pro level, the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD)], total phenolic concentration, antioxidant capacity, expression of phenylalanine ammonia lyase (PAL), γ-tocopherol methyltransferase (γ-TMT) and proline dehydrogenase (ProDH) genes, phytohormone levels such as abscisic acid (ABA), gibberellic acid (GA), indole acetic acid (IAA) and salicylic acid (SA), soluble sugars and organic acids were recorded. It was found that Pro alleviated the oxidative damage in the seedlings of lettuce as demonstrated by lower lipid peroxidation and H 2 O 2 content, increasing the endogenous Pro level, the activity of antioxidant enzymes, total phenolic concentration and the antioxidant capacity. Additionally, it was revealed that exogenous application of Pro enhanced the levels of GA, IAA, the concentrations of soluble sugars and organic acids and expressions of PAL, γ-TMT and ProDH genes as compared to the control. The results obtained in this study suggest that pre-treatment with exogenous Pro provides important contributions to the increase in the UV-B tolerance of lettuce by regulating the biochemical mechanisms of UV-B response.

  3. Speed of flame propagation in CH3Cl + Cl2 mixtures during combustion initiated by continuous UV radiation

    Science.gov (United States)

    Begishev, I. R.; Belikov, A. K.; Nikitin, I. S.

    2017-05-01

    Flame propagation in a closed tube over mixtures of chloromethane and chlorine of different compositions following ignition by continuous UV radiation is studied. It is found that the rate of combustion in all mixtures except limiting ones grows along with the propagation of the flame front up to its maximum values at nearly 1/3 the tube length and then slows. In limiting mixtures, the speed's behavior is completely different. It is greatest near the source of UV light and gradually slows with distance from the source. The high speed in the initial section is due to the effect of UV light. The temperature of combustion is lowest in limiting mixtures, and the rate of chlorine molecule photodissociation at this temperature is comparable to and even faster than that of their thermal dissociation. The light in these mixtures thus contributes substantially to the initiation of the chemical reaction. It is concluded that when limiting mixtures are ignited by UV pulses, the speed of flame propagation falls markedly as it proceeds without the influence of radiation, and the character of changes in the speed's behavior becomes identical to those for other mixtures.

  4. Inhibition of the RhoA GTPase Activity Increases Sensitivity of Melanoma Cells to UV Radiation Effects

    Directory of Open Access Journals (Sweden)

    Gisele Espinha

    2016-01-01

    Full Text Available Ultraviolet radiation is the main cause of DNA damage to melanocytes and development of melanoma, one of the most lethal human cancers, which leads to metastasis due to uncontrolled cell proliferation and migration. These phenotypes are mediated by RhoA, a GTPase overexpressed or overactivated in highly aggressive metastatic tumors that plays regulatory roles in cell cycle progression and cytoskeleton remodeling. This work explores whether the effects of UV on DNA damage, motility, proliferation, and survival of human metastatic melanoma cells are mediated by the RhoA pathway. Mutant cells expressing dominant-negative (MeWo-RhoA-N19 or constitutively active RhoA (MeWo-RhoA-V14 were generated and subjected to UV radiation. A slight reduction in migration and invasion was observed in MeWo and MeWo-RhoA-V14 cells but not in MeWo-RhoA-N19 cells, which presented inefficient motility and invasiveness associated with stress fibers fragmentation. Proliferation and survival of RhoA-deficient cells were drastically reduced by UV compared to cells displaying normal or high RhoA activity, suggesting increased sensitivity to UV. Loss of RhoA activity also caused less efficient DNA repair, with elevated levels of DNA lesions such as strand breaks and cyclobutane pyrimidine dimers (CPDs. Thus, RhoA mediates genomic stability and represents a potential target for sensitizing metastatic tumors to genotoxic agents.

  5. The PROCESS experiment: amino and carboxylic acids under Mars-like surface UV radiation conditions in low-earth orbit.

    Science.gov (United States)

    Noblet, Audrey; Stalport, Fabien; Guan, Yuan Yong; Poch, Olivier; Coll, Patrice; Szopa, Cyril; Cloix, Mégane; Macari, Frédérique; Raulin, Francois; Chaput, Didier; Cottin, Hervé

    2012-05-01

    The search for organic molecules at the surface of Mars is a top priority of the next Mars exploration space missions: Mars Science Laboratory (NASA) and ExoMars (ESA). The detection of organic matter could provide information about the presence of a prebiotic chemistry or even biological activity on this planet. Therefore, a key step in interpretation of future data collected by these missions is to understand the preservation of organic matter in the martian environment. Several laboratory experiments have been devoted to quantifying and qualifying the evolution of organic molecules under simulated environmental conditions of Mars. However, these laboratory simulations are limited, and one major constraint is the reproduction of the UV spectrum that reaches the surface of Mars. As part of the PROCESS experiment of the European EXPOSE-E mission on board the International Space Station, a study was performed on the photodegradation of organics under filtered extraterrestrial solar electromagnetic radiation that mimics Mars-like surface UV radiation conditions. Glycine, serine, phthalic acid, phthalic acid in the presence of a mineral phase, and mellitic acid were exposed to these conditions for 1.5 years, and their evolution was determined by Fourier transform infrared spectroscopy after their retrieval. The results were compared with data from laboratory experiments. A 1.5-year exposure to Mars-like surface UV radiation conditions in space resulted in complete degradation of the organic compounds. Half-lives between 50 and 150 h for martian surface conditions were calculated from both laboratory and low-Earth orbit experiments. The results highlight that none of those organics are stable under low-Earth orbit solar UV radiation conditions.

  6. Excision repair in mammalian cells. [uv radiation, N-acetoxy-2-acetylaminofluorene

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, F.E.; Setlow, R.B.

    1978-01-01

    Excision repair after combined treatments of uv and N-acetoxy-2-acetylaminofluorene (AAAF) was studied by three different techniques in cells proficient in uv excision repair and in cells deficient in uv repair. Two patterns of repair were observed: in repair proficient cells total repair was additive, and in repair deficient cells total repair was much less than additive--usually less than observed for separate treatments--and AAAF inhibited dimer excision. We conclude that in the 1st class of cells pathways for repair of uv and AAAF lesions are not identical, and in the 2nd class the residual excision enzymes are different from those in repair proficient cells.

  7. UV radiation in the melanoma capital of the world: What makes New Zealand so different?

    Science.gov (United States)

    McKenzie, Richard

    2017-02-01

    To better understand New Zealand's high rates of skin cancer, the UV climate of New Zealand is discussed in relation to other locations, and the factors contributing to geographical differences in UV are explored. Historical and projected future changes in UV are discussed in the context of what would have happened without implementation of the Montreal Protocol to protect the ozone layer. The effects of interactions due to future climate change are also discussed. Finally, the effects of our unique UV climate on human health are discussed briefly; along with changing public advice.

  8. SC79 protects retinal pigment epithelium cells from UV radiation via activating Akt-Nrf2 signaling.

    Science.gov (United States)

    Gong, Yi-Qing; Huang, Wei; Li, Ke-Ran; Liu, Yuan-Yuan; Cao, Guo-Fan; Cao, Cong; Jiang, Qin

    2016-09-13

    Excessive Ultra-violet (UV) radiation causes oxidative damages and apoptosis in retinal pigment epithelium (RPE) cells. Here we tested the potential activity of SC79, a novel small molecule activator of Akt, against the process. We showed that SC79 activated Akt in primary and established (ARPE-19 line) RPE cells. It protected RPE cells from UV damages possibly via inhibiting cell apoptosis. Akt inhibition, via an Akt specific inhibitor (MK-2206) or Akt1 shRNA silence, almost abolished SC79-induced RPE cytoprotection. Further studies showed that SC79 activated Akt-dependent NF-E2-related factor 2 (Nrf2) signaling and inhibited UV-induced oxidative stress in RPE cells. Reversely, Nrf2 shRNA knockdown or S40T mutation attenuated SC79-induced anti-UV activity. For the in vivo studies, we showed that intravitreal injection of SC79 significantly protected mouse retina from light damages. Based on these results, we suggest that SC79 protects RPE cells from UV damages possibly via activating Akt-Nrf2 signaling axis.

  9. Gas sensing properties under UV radiation of In{sub 2}O{sub 3} nanostructures processed by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Trocino, S., E-mail: trcsfn83@gmail.com [Department of Civil Engineering, Energy, Environment and Materials, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito, 89124 Reggio Calabria (Italy); Frontera, P., E-mail: patrizia.frontera@unirc.it [Department of Civil Engineering, Energy, Environment and Materials, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito, 89124 Reggio Calabria (Italy); Donato, A., E-mail: andrea.donato@unirc.it [Department of Civil Engineering, Energy, Environment and Materials, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito, 89124 Reggio Calabria (Italy); Busacca, C., E-mail: irconc@hotmail.it [Department of Civil Engineering, Energy, Environment and Materials, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito, 89124 Reggio Calabria (Italy); Scarpino, L.A., E-mail: luciano.scarpino@unirc.it [Department of Civil Engineering, Energy, Environment and Materials, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito, 89124 Reggio Calabria (Italy); Antonucci, P., E-mail: pierluigi.antonucci@unirc.it [Department of Civil Engineering, Energy, Environment and Materials, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito, 89124 Reggio Calabria (Italy); Neri, G., E-mail: gneri@unime.it [Department of Electronic Engineering, Chemistry and Industrial Engineering, University of Messina, Contrada di Dio (S. Agata), 98166 Messina (Italy)

    2014-09-15

    Manufacturing In{sub 2}O{sub 3}/PVP fibers, by sol–gel method coupled with the electrospinning technique, have been obtained In{sub 2}O{sub 3} nanostructures. The morphological and microstructural properties of as spun and annealed samples have been examined using Thermo Gravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC), X-Ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM). Characterization results provided clear indications of the formation of different In{sub 2}O{sub 3} nanostructures after annealing by changing the solvent system utilized for the electrospinning process. The sensing characteristics of the In{sub 2}O{sub 3} nanostructures synthesized have been evaluated for the monitoring of nitrogen dioxide at room temperature in the dark, under continuous ultra-violet (UV) illumination and under pulsed UV illumination (provided only during the recovery time). The effect of In{sub 2}O{sub 3} nanostructure morphology and UV radiation has been investigated and discussed. The better sensing performances (high response and very short recovery time) were registered when the sensors were irradiated with pulsed UV light. - Highlights: • Preparation and synthesis of In{sub 2}O{sub 3} nanostructures by electrospinning. • Physical and chemical characterization of prepared samples. • Investigation of the sensing properties to monitor NO{sub 2} at RT under pulsed UV light.

  10. Differential regulation of caspase-9 by ionizing radiation- and UV-induced apoptotic pathways in thymic cells

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Mayumi; Koga, Satomi [Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Hiroshima 727-0023 (Japan); Tatsuka, Masaaki, E-mail: tatsuka@pu-hiroshima.ac.jp [Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Hiroshima 727-0023 (Japan)

    2010-06-01

    In mouse thymic lymphoma 3SB cells bearing wild type p53, ionizing radiation (IR) and UV light are potent triggers of caspase-3-dependent apoptosis. Although cytochrome c was released from mitochondria as expected, caspase-9 activation was not observed in UV-exposed cells. Laser scanning confocal microscopy analysis showed that caspase-9 is localized in an unusual punctuated pattern in UV-induced apoptotic cells. In agreement with differences in the status of caspase-9 activation between IR and UV, subcellular protein fractionation experiments showed that pro-apoptotic apoptosis protease-activating factor 1 (Apaf-1), normally a part of the apoptosome assembled in response to the release of cytochrome c from mitochondria, and B-cell lymphoma extra long (Bcl-xL), an inhibitor of the change in mitochondrial membrane permeability, were redistributed by the IR-exposure but not by the UV-exposure. Instead of the sequestration of the capase-9/apoptosome activation in UV-induced apoptotic cells, the extrinsic apoptotic signaling generated by caspase-8 activation and consequent activation of B-cell lymphoma extra long (Bid) to release cytochrome c from mitochondria was observed. Thus, the post-mitochondrial apoptotic pathway downstream of cytochrome c release cannot operate the apoptosome function in UV-induced apoptosis in thymic 3SB cells. The intracellular redistribution and sequestration of apoptosis-related proteins upon mitochondrion-based apoptotic signaling was identified as a novel cellular mechanism to respond to DNA damage in an agent type-specific manner. This finding suggests that the kind of the critical ultimate apoptosis-inducing DNA lesion complex form resulting from the agent-specific DNA damage responses is important to determine which of apoptosis signals would be activated.

  11. Lipids and pigment-protein complexes of photosynthetic apparatus of Deschampsia antarctica Desv. plants under UV-B radiation

    Directory of Open Access Journals (Sweden)

    Svietlova N. B.

    2012-01-01

    Full Text Available Aim. To investigate structural and functional modifications of major components of photosynthetic membranes of endemic antarctic species D. antarctica under UV-B radiation. Methods. For quantitative determination of photosynthetic membrane components we used Arnon’s method (for chlorophylls and carotenoids; separation of carotenoids was carried out by Merzlyak’s method; polar lipids were isolated by Zill and Harmon method in modification of Yakovenko and Mihno; glycolipids separation and identification we carried out by Yamamoto method; and sulfoquinovosyl diacylglycerol content was determined by Kean method. The separation, disintegration and determination of pigment-protein complexes of chloroplasts were carried out by Anderson method. Authenticity of differences between the mean arithmetic values of indices was set after the Student criterion. Differences were considered as reliable at p 0.05. Results. We determined structural and functional changes in lipids, carotenoids and pigment-protein complexes at the photosyntetic apparatus level in D. antarctica plants under UV-B radiation. Conclusions. Adaptation of D. antarctica plants to UV-B radiation is accompanied by a cascade of physiological and biochemical rearrangements at the level of photosynthetic apparatus, manifested as the changes in pigment, lipid and pigment-protein complexes content

  12. The MRC-5 human embryonal lung fibroblast two-dimensional gel cellular protein database: quantitative identification of polypeptides whose relative abundance differs between quiescent, proliferating and SV40 transformed cells

    DEFF Research Database (Denmark)

    Celis, J E; Dejgaard, K; Madsen, Peder

    1990-01-01

    (1323 with isoelectric focusing and 572 with nonequilibrium pH gradient electrophoresis) are recorded in this database, containing quantitative and qualitative data on the relative abundance of cellular proteins synthesized by quiescent, proliferating and SV40 transformed MRC-5 fibroblasts. Of the 592......A new version of the MRC-5 two-dimensional gel cellular protein database (Celis et al., Electrophoresis 1989, 10, 76-115) is presented. Gels were scanned with a Molecular Dynamics laser scanner and processed by the PDQUEST II software. A total of 1895 [35S]methionine-labeled cellular polypeptides...

  13. Interpreting HST UV Spectra of Galactic Winds Using Radiative Transfer of Hydrodynamic Galaxy Simulations in yt

    Science.gov (United States)

    Yesuf, Hassen

    2017-08-01

    Understanding gas in galaxies and its movement as galactic winds in particular is critical in galaxy formation and evolution studies. While enormous progress has been made in the last decade, the detailed properties (spatial distribution, ionization state, phase and kinematic structure) of gas in and around galaxies are still poorly constrained. HST observations have been instrumental in advancing the study of the complex multi-phase galactic winds. However, they have been interpreted using useful but simple wind models. With the advent of advanced high resolution hydrodynamic cosmological galaxy simulations, which claim to realistically model gas and metal distributions in galaxies and self-consistently generate winds, it is time to develop more sophisticated wind models to interpret the observations and also make simulation outputs into observable spectra. To that end, we propose to use the existing 3D radiative transfer (RT) wind model of Prochaska et al. 2011 to post-process the outputs from state-of-art hydrodynamic simulations. In addition to developing interpretive tools to study galactic winds, we will produce a large suite of synthetic mock HST UV spectra (including noise and instrument effects) for robust and unprecedented comparison between wind observations and theory. We will share our analysis tools and thousands of mock wind profiles and emission-line maps of varying galaxy properties, viewing angles, signal-to-noise and redshift with the community. Effort will be made to use machine-learning techniques to analyze these mock spectra. Finally, we will compare our analysis with other wind models that approximate the RT process and assess their accuracy.

  14. Assessment of Resistance of Bacillus Horneckiae Endospores to UV Radiation and Function of Their Extraneous Layer in Resistance

    Science.gov (United States)

    Zachariah, Malcolm M.; Vaishampayan, Parag

    2011-01-01

    Spore-forming microbes are highly resistant to various physical and chemical conditions, which include ionizing and UV radiation, desiccation and oxidative stress, and the harsh environment of outer space or planetary surfaces. The spore's resistance might be due to their metabolically dormant state, and/or by the presence of a series of protective structures that encase the interior-most compartment, the core, which houses the spore chromosome. These spores have multiple layers surrounding the cell that are not found in vegetative cells, and some species have an outer layer of proteins and glycoproteins termed the "exosporium" or a fibrous "extraneous layer" (EL). Bacillus horneckiae is an EL-producing novel sporeformer isolated from a Phoenix spacecraft assembly clean room, and it has previously demonstrated resistance to UV radiation up to 1000 J/m(sup 2). The EL appears to bind B. horneckiae spores into large aggregations, or biofilms, and may confer some UV resistance to the spores. Multiple culturing and purification schemes were tried to achieve high purity spores because vegetative cells would skew UV resistance results. An ethanol-based purification scheme produced high purity spores. Selective removal of the EL from spores was attempted with two schemes: a chemical extraction method and physical extraction (sonication). Results from survival rates in the presence and absence of the external layer will provide a new understanding of the role of biofilms and passive resistance that may favor survival of biological systems in aggressive extra-terrestrial environments. The chemical extraction method decreased viable counts of spores and lead to an inconclusive change UV resistance relative to non-extracted spores. The physical extraction method lead to non-aggregated spores and did not alter viability; however, it produced UV resistance profiles similar to non-extracted spores. In addition to the EL-removal study, samples of B. horneckiae spores dried on

  15. 2-D DIGE analysis of UV-C radiation-responsive proteins in globe artichoke leaves

    NARCIS (Netherlands)

    Falvo, S.; Carli, Di M.; Desiderio, A.; Benvenuto, E.; Moglia, A.; America, A.H.P.; Lanteri, S.; Acquadro, A.

    2012-01-01

    Plants respond to ultraviolet stress inducing a self-defence through the regulation of specific gene family members. The UV acclimation is the result of biochemical and physiological processes, such as enhancement of the antioxidant enzymatic system and accumulation of UV-absorbing phenolic

  16. Reconstruction of the erythemal UV radiation data in Novi Sad (Serbia) using the NEOPLANTA parametric model

    Science.gov (United States)

    Malinovic-Milicevic, S.; Mihailovic, D. T.; Radovanovic, M. M.

    2015-07-01

    This paper focuses on the development and application of a technique for filling the daily erythemal UV dose data gaps and the reconstruction of the past daily erythemal UV doses in Novi Sad, Serbia. The technique implies developing the empirical equation for estimation of daily erythemal UV doses by means of relative daily sunshine duration under all sky conditions. A good agreement was found between modeled and measured values of erythemal UV doses. This technique was used for filling the short gaps in the erythemal UV dose measurement series (2003-2009) as well as for the reconstruction of the past time-series values (1981-2002). Statistically significant positive erythemal UV dose trend of 6.9 J m-2 per year was found during the period 1981-2009. In relation to the reference period 1981-1989, an increase in the erythemal UV dose of 6.92 % is visible in the period 1990-1999 and the increase of 9.67 % can be seen in the period 2000-2009. The strongest increase in erythemal UV doses has been found for winter and spring seasons.

  17. How do environmental and behavioral factors impact ultraviolet radiation effects on health: the RISC-UV Project

    Science.gov (United States)

    Correa, M. P.; Godin-Beekmann, S.; Haeffelin, M.; Saiag, P.; Mahe, E.; Brogniez, C.; Dupont, J. C.; Pazmiño, A.; Auriol, F.; Bonnel, B.

    2009-04-01

    Introduction: RISC-UV is a research project on "Impact of climate change on ultraviolet radiation and risks for health", a research project in which physicists, meteorologists and physicians work together to assess the relative role played by environmental and behavioral factors in the UV-related diseases as skin cancer and vitamin D deficiency. Environmental factors are related to the role played by the alteration in intensity of UV radiation at the Earth's surface resulting from variation in several factors affected by climate change and human activities: stratospheric ozone, cloud cover, aerosols and the reflectivity of the surface. On the other hand, behavioral factors are related to the sun over/underexposure and the correct use of sun-protection (hats, caps, sunglasses, sunscreen lotion, etc.). RISC-UV is organized around three main areas: 1) Organization of a workshop, scheduled for January 2009, which aims to describe the state of the art in the subject within each community and define the requirements of pathologists for epidemiological studies; 2) A pilot study intended to evaluate the consistency between UV measurements delivered simultaneously by satellite-based instruments, ground instruments, radiometers and individual dosimeters. This study is based on measurements campaigns and an analysis of the long-term consistency of data series relating to UV radiation and associated parameters; and 3) Analysis of the weights of medical, behavioral and environmental parameters involved in skin carcinogenesis. A detailed description of these areas can be found in http://www.gisclimat.fr/Doc/GB/D_projects/RISC-UV_GB.html. This presentation focuses on the first results of the UV experimental measurements performed between September 8th and October 8th 2008 in Palaiseau, France (48.7˚ N; 2.2˚ E; 170m - Haeffelin et al., 2005). A second campaign is foreseen for the spring of 2009. The purpose of these campaigns is to obtain, analyze and quantitatively link the

  18. Knowledge of outdoor workers on the effects of natural UV radiation and methods of protection against exposure.

    Science.gov (United States)

    Hault, K; Rönsch, H; Beissert, S; Knuschke, P; Bauer, A

    2016-04-01

    The most important but influenceable risk factor in the development of skin cancer is the unprotected exposure to solar ultraviolet (UV) radiation. In order to assure adequate and effective protection against UV exposure, a level of knowledge about solar radiation and its effects is required. The objective of this study was to assess the knowledge of workers in outdoor professions on the effects of natural UV radiation and methods of protection against exposure. Forty outdoor workers were given a standardized questionnaire designed to ascertain their level of knowledge. The majority of participants knew exposure to solar radiation can be detrimental depending on exposure time. Eighty-three percentage recognized that people working regularly in an outdoor environment may be at risk due to high exposure. Long-sleeved clothing plus headgear and sunscreen containing sun-protecting substances were deemed adequate methods of protection by 83% and 85% respectively. Seventy percentage of the outdoor workers were familiar with the definition of the sun protection factor (SPF), yet only 25% correctly identified the amount of sunscreen needed to achieve the SPF as indicated on the product. A mere 8% of participants knew that symptoms of a sunburn first became apparent 3 h after sun exposure and only 18% were able to accurately gauge the amount of time they could spend in the sun before developing one. Although 30% had heard of the ultraviolet index (UVI), only 13% understood that protecting your skin using additional measures is recommended as of UVI 3. Overall, 30% of the outdoor workers thought themselves sufficiently protected against the harmful effects of the sun. While the participants of this study had a basic fundamental understanding of the effects of solar radiation and methods of protection against exposure, there remains an urgent need for further clarification across all demographic groups. © 2016 European Academy of Dermatology and Venereology.

  19. Effects of PAR and UV-B radiation on herbal yield, bioactive compounds and their antioxidant capacity of some medicinal plants under controlled environmental conditions.

    Science.gov (United States)

    Manukyan, Artur

    2013-01-01

    Photosynthetically active radiation (PAR) and Ultraviolet B (UV-B) radiation are among the main environmental factors acting on herbal yield and biosynthesis of bioactive compounds in medicinal plants. The objective of this study was to evaluate the influence of biologically effective UV-B light (280-315 nm) and PAR (400-700 nm) on herbal yield, content and composition, as well as antioxidant capacity of essential oils and polyphenols of lemon catmint (Nepeta cataria L. f. citriodora), lemon balm (Melissa officinalis L.) and sage (Salvia officinalis L.) under controlled greenhouse cultivation. Intensive UV-B radiation (2.5 kJ m(-2)  d(-1) ) influenced positively the herbal yield. The essential oil content and composition of studied herbs were mainly affected by PAR and UV-B radiation. In general, additional low-dose UV-B radiation (1 kJ m(-2) d(-1) ) was most effective for biosynthesis of polyphenols in herbs. Analysis of major polyphenolic compounds provided differences in sensitivity of main polyphenols to PAR and UV-B radiation. Essential oils and polyphenol-rich extracts of radiated herbs showed essential differences in antioxidant capacity by the ABTS system. Information from this study can be useful for herbal biomass and secondary metabolite production with superior quality under controlled environment conditions. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  20. UV stability of HMS-PP (high melt strength polypropylene) obtained by radiation process

    Energy Technology Data Exchange (ETDEWEB)

    Oliani, W.L., E-mail: washoliani@usp.b [Nuclear Energy Research Institute-IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, 05508-900 Sao Paulo (Brazil); Parra, D.F.; Lugao, A.B. [Nuclear Energy Research Institute-IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, 05508-900 Sao Paulo (Brazil)

    2010-03-15

    HMS-PP in grains was synthesized by the gamma irradiation of PP under a crosslinking atmosphere of acetylene, followed by thermal treatment for radical recombination and thermal treatment for annihilation of the remaining radicals. The UV stability of the material was evaluated in pellet form. The accelerated weathering test of HMS-PP samples were performed under artificial ultra-violet light and in a condensation chamber Comexim (C-UV type) apparatus with UV exposure for 120 and 240 h. The results were compared to those from ageing caused by sunlight and dew under natural exposition. This work investigated changes in mechanical proprieties (elongation and rupture strength), Fourier transform infrared spectroscopy (FTIR), optical microscopy (MO), scanning electron microscopy (SEM) and rheological properties of HMS-PP after the UV ageing. We find that the HMS-PP has more degradation than regular PP and undergoes predominate chain scission in aggressive UV ageing conditions.

  1. The effects of UV-B radiation intensity on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum.

    Science.gov (United States)

    Yao, Xiao-Qin; Chu, Jian-Zhou; He, Xue-Li; Si, Chao

    2014-01-01

    The article studied UV-B effects on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum during the bud stage. The experiment included four UV-B radiation levels (CK, ambient UV-B; T1, T2 and T3 indicated a 5%, 10% and 15% increase in ambient UV-BBE, respectively) to determine the optimal UV-B radiation intensity in regulating active ingredients level in flowers of two chrysanthemum varieties. Flower dry weight of two cultivars was not affected by UV-B radiation under experimental conditions reported here. UV-B treatments significantly increased the rate of superoxide radical production, hydrogen peroxide (H2O2) (except for T1) and malondialdehyde concentration in flowers of Huai chrysanthemum and H2O2 concentration in flowers of Qi chrysanthemum. T2 and T3 treatments induced a significant increase in phenylalanine ammonia lyase enzyme (PAL) activity, anthocyanins, proline, ascorbic acid, chlorogenic acid and flavone content in flowers of two chrysanthemum varieties, and there were no significant differences in PAL activity, ascorbic acid, flavone and chlorogenic acid content between the two treatments. These results indicated that appropriate UV-B radiation intensity did not result in the decrease in flower yield, and could regulate PAL activity and increase active ingredients content in flowers of two chrysanthemum varieties. © 2014 The American Society of Photobiology.

  2. Impact of solar UV radiation on toxicity of ZnO nanoparticles through photocatalytic reactive oxygen species (ROS) generation and photo-induced dissolution

    Science.gov (United States)

    The present study investigated the impact of solar UV radiation on ZnO nanoparticle toxicity through photocatalytic ROS generation and photo-induced dissolution. Toxicity of ZnO nanoparticles to Daphnia magna was examined under laboratory light versus simulated solar UV radiatio...

  3. Study of Leaf Metabolome Modifications Induced by UV-C Radiations in Representative Vitis, Cissus and Cannabis Species by LC-MS Based Metabolomics and Antioxidant Assays

    Directory of Open Access Journals (Sweden)

    Guillaume Marti

    2014-09-01

    Full Text Available UV-C radiation is known to induce metabolic modifications in plants, particularly to secondary metabolite biosynthesis. To assess these modifications from a global and untargeted perspective, the effects of the UV-C radiation of the leaves of three different model plant species, Cissus antarctica Vent. (Vitaceae, Vitis vinifera L. (Vitaceae and Cannabis sativa L. (Cannabaceae, were evaluated by an LC-HRMS-based metabolomic approach. The approach enabled the detection of significant metabolite modifications in the three species studied. For all species, clear modifications of phenylpropanoid metabolism were detected that led to an increased level of stilbene derivatives. Interestingly, resveratrol and piceid levels were strongly induced by the UV-C treatment of C. antarctica leaves. In contrast, both flavonoids and stilbene polymers were upregulated in UV-C-treated Vitis leaves. In Cannabis, important changes in cinnamic acid amides and stilbene-related compounds were also detected. Overall, our results highlighted phytoalexin induction upon UV-C radiation. To evaluate whether UV-C stress radiation could enhance the biosynthesis of bioactive compounds, the antioxidant activity of extracts from control and UV-C-treated leaves was measured. The results showed increased antioxidant activity in UV-C-treated V. vinifera extracts.

  4. Time sequence of the damage to the acceptor and donor sides of photosystem II by UV-B radiation as evaluated by chlorophyll a fluorescence

    NARCIS (Netherlands)

    Rensen, van J.J.S.; Vredenberg, W.J.; Rodrigues, G.C.

    2007-01-01

    The effects of ultraviolet-B (UV-B) radiation on photosystem II (PS II) were studied in leaves of Chenopodium album. After the treatment with UV-B the damage was estimated using chlorophyll a fluorescence techniques. Measurements of modulated fluorescence using a pulse amplitude modulated

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

    Science.gov (United States)

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

    2015-01-01

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Impact of UV-B radiation on the digestive enzymes and immune system of larvae of Indian major carp Catla catla.

    Science.gov (United States)

    Sharma, Jaigopal; Rao, Y Vasudeva; Kumar, S; Chakrabarti, Rina

    2010-03-01

    Ultraviolet radiation is a potent threat to the aquatic animals. Exposure to such stressor affects metabolic and immunological processes. The present investigation aims to study the effect of UV-B radiation on digestive enzymes and immunity of larvae of Catla catla. Larvae were exposed to ultraviolet-B (UV-B, 280-320 nm) radiation (145 microW/cm(2)) for three different exposure times of 5, 10 and 15 min on every other day. After 55 days, important digestive enzymes were assayed. For immunological study, lysozyme, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) levels were measured. Then the fish were kept for one month without radiation and lysozyme level was measured. Protein concentration varied directly with the duration of exposure and was highest among fish that had received the 15 min UV-B irradiation. Significantly higher amylase, protease, trypsin and chymotrypsin activities were found in 5 min exposed fish compared to others. Lysozyme level was significantly higher in control group compared to the UV-B treated fish. The lysozyme level decreased with the increasing duration of UV-B radiation. When fish were kept without UV-B radiation for one month, lysozyme level was brought to the normal level in all treatments, except 15 min exposed fish. The GOT and GPT levels were significantly higher in the 15 min exposed group than others. The effects of UV-B radiation on the digestive physiology and immune system of catla have been clearly observed in the present study. The decreased enzyme activities in UV-B radiated fish results into improper digestion and poor growth.

  7. Heated water and UV-C radiation to post harvest control of Cryptosporiopsis perennans on apples; Agua aquecida e radiacao UV-C no controle pos-colheita de Cryptosporiopsis perennans em macas

    Energy Technology Data Exchange (ETDEWEB)

    Bartnicki, Vinicius Adao; Amarante, Cassandro Vidal Talamini do, E-mail: vinibart@hotmail.co, E-mail: amarante@cav.udesc.b [Universidade do Estado de Santa Catarina (UDESC), Lages, SC (Brazil). Centro de Ciencias Agroveterinarias. Dept. de Agronomia; Valdebenito-Sanhueza, Rosa Maria, E-mail: rosamaria@m2net.com.b [Proterra Engenharia Agronomica, Vacaria, RS (Brazil); Castro, Luis Antonio Suita de, E-mail: suita@cpact.embrapa.b [EMBRAPA Clima Temperado, Pelotas, RS (Brazil); Rizzatti, Mara Regina; Souza, Joao Antonio Vargas de, E-mail: marar@pucrs.b [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Centro em Pesquisa e Desenvolvimento em Fisica. Grupo de Fisica das Radiacoes

    2010-02-15

    The objective of this work was to assess the colonization of Cryptosporiopsis perennans in the epidermis of apples and the efficiency of heated water and UV-C radiation application to control this pathogen. In apples inoculated with C. perennans, the colonization of lenticels and adjacent areas by the pathogen was observed by electronic scanning microscopy. The sensitivity of C. perennans conidia was evaluated in aqueous suspension, at temperatures of 28, 45, 50 and 55 deg C for 15 and 30 s, and at UV.C radiation doses of 0.018, 0.037, 0.075, 0.150, 0.375, 0.750, 1.500 and 3.000 kJ m.2. The effects of UV.C radiation doses at 0.375, 0.750 and 1.500 kJ m.2 and heated water at 50 deg C, sprayed during 15 and 30 s were evaluated for controlling C. perennans in apples inoculated with the pathogen. The fungus produced abundant mycelium and conidia in lenticels and adjacent areas on the epidermis of the apples. The heated water at 50 deg C during 15 s and a 0.750 kJ m.2 UV.C radiation dose reduced conidia survival in more than 99%. Heated water sprayed at 50 deg C during 15 s and a UV.C radiation dose of 0.375 kJ m.2 control C. perennans in apples. (author)

  8. From UV Protection to Protection in the Whole Spectral Range of the Solar Radiation: New Aspects of Sunscreen Development.

    Science.gov (United States)

    Zastrow, Leonhard; Meinke, Martina C; Albrecht, Stephanie; Patzelt, Alexa; Lademann, Juergen

    2017-01-01

    Sunscreens have been constantly improving in the past few years. Today, they provide an efficient protection not only in the UVB but also in the UVA spectral region of the solar radiation. Recently it could be demonstrated that 50% of all free radicals induced in the skin due to solar radiation are formed in the visible and infrared spectral region. The good protective efficacy of sunscreens in the UV region prompts people to stay much longer in the sun than if they had left their skin unprotected. However, as no protection in the visible and infrared spectral region is provided, high amounts of free radicals are induced here that could easily exceed the critical radical concentration. This chapter describes how the effect of sunscreens can be extended to cover also the visible and infrared spectral region of the solar radiation by adding pigments and antioxidants with high radical protection factors to the sunscreen formulations.

  9. Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

    Energy Technology Data Exchange (ETDEWEB)

    Feister, Uwe [German Meteorological Service, Meteorological Observatory Lindenberg - Richard-Assmann-Observatory, Am Observatorium 12, 15848 Lindenberg (Germany); Meyer, Gabriele; Kirst, Ulrich [German Social Accident Insurance Institution for Transport and Traffic, Ottenser Hauptstrasse 54, 22765 Hamburg (Germany)

    2013-05-10

    Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels. The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.

  10. NH4+ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta).

    Science.gov (United States)

    Xu, Zhiguang; Gao, Kunshan

    2012-01-01

    Solar ultraviolet radiation (UVR, 280-400 nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280-315 nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315-400 nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Reduction of UV-B radiation causes an enhancement of photoinhibition in high light stressed aquatic plants from New Zealand lakes.

    Science.gov (United States)

    Hanelt, Dieter; Hawes, Ian; Rae, Rowena

    2006-08-01

    Anthropogenic stratospheric ozone depletion causes an increase of UV-B radiation impinging on the earth surface, which is a threat to plants not adapted to higher UV-B irradiances. Investigations were undertaken with aquatic plants from New Zealand, where UV-irradiances are naturally higher due to the southern latitude, to compare with former results of polar species. The experiments reported in this study were undertaken with plants collected from different lakes of the South Island, with different UV transparencies. Photoinhibition was induced under controlled conditions using a sun simulator, which mimicked the natural underwater radiation spectrum. Photosynthetic activity during high light stress, and during recovery in dim light, was determined in vivo by measuring fluorescence changes, using a PAM fluorometer device. A comparison of different species showed that the extent to which UV causes an additional decrease of photosynthetic performance during high light stress varies according to the depth of growth and UV transparency of the water body. This observation fits with previous studies. However, a new finding was that some species were even more strongly inhibited when UV-B was filtered out of the simulated sun spectrum, indicating a supporting effect of the short UVR wavelength range against photoinhibition. These results were also confirmed by field experiments under natural radiation conditions. Thus, UV-B does not solely cause negative effects on photosynthesis, but it may even support recovery processes in aquatic plants adapted to a high UV-radiation environment. The latter is in contrast to earlier studies, in which UV-B radiation was considered causing only harmful effects on photosynthesis of aquatic plants.

  12. Flavonoid concentrations in three grass species and a sedge grown in the field and under controlled environment conditions in response to enhanced UV-B radiation.

    Science.gov (United States)

    van de Staaij, J; de Bakker, N V J; Oosthoek, A; Broekman, R; van Beem, A; Stroetenga, M; Aerts, R; Rozema, J

    2002-02-01

    An investigation was carried out to find whether enhanced levels of UV-B radiation induce increased concentrations of flavonoids in the leaves of the grass species Deschampsia antarctica, Deschampsia borealis and Calamagrostis epigeios and the sedge Carex arenaria. Whether the enhanced levels of UV-B influenced the proportions of the various flavonoids in the leaves was also studied. Increased flavonoid concentrations would improve the UV-B shielding of UV-B susceptible tissues. Using HPLC analysis the flavonoids orientin and luteolin were identified in D. antarctica, orientin in D. borealis and tricin in C. arenaria. Neither flavonoid concentrations nor the proportion of the various flavonoids in climate room grown D. antarctica and D. borealis plants differed between individuals grown under 0, ambient or elevated UV-B levels. After 12 weeks of growth biomass production and shoot-to-root ratios of D. antarctica were not affected by elevated UV-B radiation. Greenhouse grown C. epigeios plants contained higher concentrations and different proportions of flavonoids grown under elevated levels of UV-B than when grown under ambient or 0 UV-B. In C. epigeios plants grown in their natural habitat in the field under ambient or elevated levels of UV-B, flavonoid concentrations and proportions were the same in plants from both treatments. In the leaves of the sedge C. arenaria grown in a greenhouse flavonoid concentrations and proportions were not affected by UV-B radiation. Leaves were harvested four times during the growing season from C. arenaria plants grown in their natural habitat in the field under ambient or elevated levels of UV-B. Leaves harvested in January contained higher concentrations of flavonoids when grown under elevated UV-B than when grown under ambient UV-B radiation. In leaves harvested in May, September and December flavonoid concentrations were the same in plants grown under ambient or elevated UV-B. The proportion of the different flavonoids was the

  13. Ultra-wide band electromagnetic radiation does not affect UV-induced recombination and mutagenesis in yeast.

    Science.gov (United States)

    Pakhomova, O N; Belt, M L; Mathur, S P; Lee, J C; Akyel, Y

    1998-01-01

    Cell samples of the yeast Saccharomyces cerevisiae were exposed to 100 J/m2 of 254 nm ultraviolet (UV) radiation followed by a 30 min treatment with ultra-wide band (UWB) electromagnetic pulses. The UWB pulses (101-104 kV/m, 1.0 ns width, 165 ps rise time) were applied at the repetition rates of 0 Hz (sham), 16 Hz, or 600 Hz. The effect of exposures was evaluated from the colony-forming ability of the cells on complete and selective media and the number of aberrant colonies. The experiments established no effect of UWB exposure on the UV-induced reciprocal and non-reciprocal recombination, mutagenesis, or cell survival.

  14. Micro-organism re-growth in wastewater disinfected by UV radiation and ozone: a micro-biological study.

    Science.gov (United States)

    Alonso, E; Santos, A; Riesco, P

    2004-04-01

    A series of disinfection experiments using UV radiation and ozone was performed on the secondary effluent from a wastewater treatment plant at a pilot plant scale. The microbial population in the inflowing wastewater and the treated outflow water were quantified for each of the treatment modules (fecal coliforms, fecal streptococci, Salmonella spp. (presence/absence), Clostridium Sulphite-reducers, Pseudomonas aeruginosa, Staphylococcus aureus, coliphages, nematodes, intestinal nematodes and pathogenic fungi). Treated water was stored in opaque tanks at a temperature between 20 and 22 degrees C, after which, a one-month study of the regrowth of the bacterial flora, nematodes and fungi was carried out. Clostridium Sulphite-reducers, pathogenic fungi and nematodes were the micro-organisms showing a greatest degree of resistence to UV- and Ozone-treatment. It was only concerning Clostridium and Pseudomonas abatement that significant elimination results were achieved with both technologies.

  15. The combination effect of hindered amine light stabilizers with UV absorbers on the radiation resistance of polypropylene

    Science.gov (United States)

    Jia, Haishun; Wang, Huiliang; Chen, Wenxiu

    2007-07-01

    The UV absorber 2-(2'-hydroxy-3',5'-dipentyl-phenyl) benzotriazole (Tinuvin 328) shows excellent stabilizing effectiveness in the γ-ray-induced degradation of polypropylene (PP). Antagonism was observed when hindered amine light stabilizers were used with benzotriazole type UV absorbers. The carbonyl index and hydroxyl index, the hydroperoxide concentration, the mass change and the relative concentration of alkyl free radicals of irradiated samples were measured. Tinuvin 328 could effectively inhibit the formation of alkyl free radicals in PP under γ-irradiation, and it is possibly the fundamental reason for its high stabilizing efficiency. A mechanism of dissipating radiation energy for Tinuvin 328 was proposed. Some reactions yet unknown between the two stabilizers decreased their stabilizing effectiveness.

  16. Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: a review.

    Science.gov (United States)

    Hijnen, W A M; Beerendonk, E F; Medema, G J

    2006-01-01

    UV disinfection technology is of growing interest in the water industry since it was demonstrated that UV radiation is very effective against (oo)cysts of Cryptosporidium and Giardia, two pathogenic micro-organisms of major importance for the safety of drinking water. Quantitative Microbial Risk Assessment, the new concept for microbial safety of drinking water and wastewater, requires quantitative data of the inactivation or removal of pathogenic micro-organisms by water treatment processes. The objective of this study was to review the literature on UV disinfection and extract quantitative information about the relation between the inactivation of micro-organisms and the applied UV fluence. The quality of the available studies was evaluated and only high-quality studies were incorporated in the analysis of the inactivation kinetics. The results show that UV is effective against all waterborne pathogens. The inactivation of micro-organisms by UV could be described with first-order kinetics using fluence-inactivation data from laboratory studies in collimated beam tests. No inactivation at low fluences (offset) and/or no further increase of inactivation at higher fluences (tailing) was observed for some micro-organisms. Where observed, these were included in the description of the inactivation kinetics, even though the cause of tailing is still a matter of debate. The parameters that were used to describe inactivation are the inactivation rate constant k (cm(2)/mJ), the maximum inactivation demonstrated and (only for bacterial spores and Acanthamoeba) the offset value. These parameters were the basis for the calculation of the microbial inactivation credit (MIC="log-credits") that can be assigned to a certain UV fluence. The most UV-resistant organisms are viruses, specifically Adenoviruses, and bacterial spores. The protozoon Acanthamoeba is also highly UV resistant. Bacteria and (oo)cysts of Cryptosporidium and Giardia are more susceptible with a fluence

  17. Solar UV-B radiation and ethylene play a key role in modulating effective defenses against Anticarsia gemmatalis larvae in field-grown soybean.

    Science.gov (United States)

    Dillon, Francisco M; Tejedor, M Daniela; Ilina, Natalia; Chludil, Hugo D; Mithöfer, Axel; Pagano, Eduardo A; Zavala, Jorge A

    2018-02-01

    Solar UV-B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV-B mediated increment of plant resistance are unknown in crops species, such as soybean. Here, we studied defense-related responses in undamaged and Anticarsia gemmatalis larvae-damaged leaves of two soybean cultivars grown under attenuated or full solar UV-B radiation. We determined changes in jasmonates, ethylene (ET), salicylic acid, trypsin protease inhibitor activity, flavonoids, and mRNA expression of genes related with defenses. ET emission induced by Anticarsia gemmatalis damage was synergistically increased in plants grown under solar UV-B radiation and was positively correlated with malonyl genistin concentration, trypsin proteinase inhibitor activity and expression of IFS2, and the pathogenesis protein PR2, while was negatively correlated with leaf consumption. The precursor of ET, aminocyclopropane-carboxylic acid, applied exogenously to soybean was sufficient to strongly induce leaf isoflavonoids. Our results showed that in field-grown soybean isoflavonoids were regulated by both herbivory and solar UV-B inducible ET, whereas flavonols were regulated by solar UV-B radiation only and not by herbivory or ET. Our study suggests that, although ET can modulate UV-B-mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids, are regulated by ET alone. © 2017 John Wiley & Sons Ltd.

  18. Effects of UV-B radiation and periodic desiccation on the morphogenesis of the edible terrestrial cyanobacterium Nostoc flagelliforme.

    Science.gov (United States)

    Feng, Yan-Na; Zhang, Zhong-Chun; Feng, Jun-Li; Qiu, Bao-Sheng

    2012-10-01

    The terrestrial cyanobacterium Nostoc flagelliforme Berk. et M. A. Curtis has been a popular food and herbal ingredient for hundreds of years. To meet great market demand and protect the local ecosystem, for decades researchers have tried to cultivate N. flagelliforme but have failed to get macroscopic filamentous thalli. In this study, single trichomes with 50 to 200 vegetative cells were induced from free-living cells by low light and used to investigate the morphogenesis of N. flagelliforme under low UV-B radiation and periodic desiccation. Low-fluence-rate UV-B (0.1 W m(-2)) did not inhibit trichome growth; however, it significantly increased the synthesis of extracellular polysaccharides and mycosporine-like amino acids and promoted sheath formation outside the trichomes. Under low UV-B radiation, single trichomes developed into filamentous thalli more than 1 cm long after 28 days of cultivation, most of which grew separately in liquid BG11 medium. With periodic desiccation treatment, the single trichomes formed flat or banded thalli that grew up to 2 cm long after 3 months on solid BG11 medium. When trichomes were cultivated on solid BG11 medium with alternate treatments of low UV-B and periodic desiccation, dark and scraggly filamentous thalli that grew up to about 3 cm in length after 40 days were obtained. In addition, the cultivation of trichomes on nitrogen-deficient solid BG11 medium (BG11(0)) suggested that nitrogen availability could affect the color and lubricity of newly developed thalli. This study provides promising techniques for artificial cultivation of N. flagelliforme in the future.

  19. Low-level laser therapy: Effects on human face aged skin and cell viability of HeLa cells exposed to UV radiation

    Directory of Open Access Journals (Sweden)

    Mezghani Sana

    2015-01-01

    Full Text Available Chronic and excessive exposure to UV radiation leads to photoaging and photocarcinogenesis. Adequate protection of the skin against the deleterious effects of UV irradiation is essential. Low-level laser therapy (LLLT is a light source in the red to near-infrared range that has been accepted in a variety of medical applications. In this study, we explored the effect of LLLT in human face aged skin and the cell viability of HeLa cells exposed to UV radiation. We found that LLLT significantly reduced visible wrinkles and the loss of firmness of facial skin in aging subjects. Additionally, treatment of cultured HeLa cells with LLLT prior to or post UVA or UVB exposure significantly protected cells from UV-mediated cell death. All results showed the beneficial effects of LLLT on relieving signs of skin aging and its prevention and protection of the cell viability against UV-induced damage.

  20. Response and Defense Mechanisms of Taxus chinensis Leaves Under UV-A Radiation are Revealed Using Comparative Proteomics and Metabolomics Analyses.

    Science.gov (United States)

    Zheng, Wen; Komatsu, Setsuko; Zhu, Wei; Zhang, Lin; Li, Ximin; Cui, Lei; Tian, Jingkui

    2016-09-01

    Taxus chinensis var. mairei is a species endemic to south-eastern China and one of the natural sources for the anticancer medicine paclitaxel. To investigate the molecular response and defense mechanisms of T. chinensis leaves to enhanced ultraviolet-A (UV-A) radiation, gel-free/label-free and gel-based proteomics and gas chromatography-mass spectrometry (GC-MS) analyses were performed. The transmission electron microscopy results indicated damage to the chloroplast under UV-A radiation. Proteomics analyses in leaves and chloroplasts showed that photosynthesis-, glycolysis-, secondary metabolism-, stress-, and protein synthesis-, degradation- and activation-related systems were mainly changed under UV-A radiation. Forty-seven PSII proteins and six PSI proteins were identified as being changed in leaves and chloroplasts under UV-A treatment. This indicated that PSII was more sensitive to UV-A than PSI as the target of UV-A light. Enhanced glycolysis, with four glycolysis-related key enzymes increased, provided precursors for secondary metabolism. The 1-deoxy-d-xylulose-5-phosphate reductoisomerase and 4-hydroxy-3-methylbut-2-enyl diphosphate reductase were identified as being significantly increased during UV-A radiation, which resulted in paclitaxel enhancement. Additionally, mRNA expression levels of genes involved in the paclitaxel biosynthetic pathway indicated a down-regulation under UV-A irradiation and up-regulation in dark incubation. These results reveal that a short-term high dose of UV-A radiation could stimulate the plant stress defense system and paclitaxel production. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    Science.gov (United States)

    Herkovits, J.; D’Eramo, J. L.; Fridman, O.

    2006-01-01

    The exposure of Bufo arenarum embryos to 300–310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. PMID:16823076

  2. Complex responses of intertidal molluscan embryos to a warming and acidifying ocean in the presence of UV radiation.

    Directory of Open Access Journals (Sweden)

    Andrew R Davis

    Full Text Available Climate change and ocean acidification will expose marine organisms to synchronous multiple stressors, with early life stages being potentially most vulnerable to changing environmental conditions. We simultaneously exposed encapsulated molluscan embryos to three abiotic stressors-acidified conditions, elevated temperate, and solar UV radiation in large outdoor water tables in a multifactorial design. Solar UV radiation was modified with plastic filters, while levels of the other factors reflected IPCC predictions for near-future change. We quantified mortality and the rate of embryonic development for a mid-shore littorinid, Bembicium nanum, and low-shore opisthobranch, Dolabrifera brazieri. Outcomes were consistent for these model species with embryos faring significantly better at 26°C than 22°C. Mortality sharply increased at the lowest temperature (22°C and lowest pH (7.6 examined, producing a significant interaction. Under these conditions mortality approached 100% for each species, representing a 2- to 4-fold increase in mortality relative to warm (26°C non-acidified conditions. Predictably, development was more rapid at the highest temperature but this again interacted with acidified conditions. Development was slowed under acidified conditions at the lowest temperature. The presence of UV radiation had minimal impact on the outcomes, only slowing development for the littorinid and not interacting with the other factors. Our findings suggest that a warming ocean, at least to a threshold, may compensate for the effects of decreasing pH for some species. It also appears that stressors will interact in complex and unpredictable ways in a changing climate.

  3. Allocation of carbon to growth and secondary metabolites in birch seedlings under UV-B radiation and CO{sub 2} exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lavola, A.; Julkunen-Tiitto, R. [Univ. of Joensuu, Dept. of Biology, Joensuu (Finland); Rosa, T.M. de la [Univ. of Joensuu, Faculty of Forestry, Joensuu (Finland)

    2000-07-01

    In plants, the allocation of carbon to secondary metabolites has been shown to be determined by both the availability of resources (e.g., CO{sub 2} concentration) and by specific stress factors (e.g., ultraviolet [UV]-radiation). It has been suggested that, in combination, CO{sub 2} and UV-B radiation may differentially affect plant growth and morphogenic parameters, and elevated CO{sub 2} may ameliorate the effects of UV-B radiation, In the present work, the effects of increased atmospheric CO{sub 2} concentration and UV-B radiation on growth and the accumulation of different types of secondary metabolites were studied in silver birch (Betula pendula Roth). Seedlings were exposed to 350 and 700 {mu} mol mol{sup -1} of CO{sub 2} in a greenhouse. At both CO{sub 2} levels, additional UV-B was either present (8.16 kJ m{sup -2} day{sup -1} of biologically effective UV-B irradiance) or absent. The time course of accumulation of individual secondary compounds and the shifts in allocation of carbon between biomass and the secondary metabolites (phenolic acids, flavonoids, condensed tannins) were studied during a 1-month-long exposure. Additionally, the activities of enzymes (L-phenylalanine ammonia-lyase [PAL], EC 4.3.1.5; peroxidase, EC 1.11.1.7; polyphenol oxidase, EC 1.10.3.1) were determined for leaves. UV-B radiation significantly increased biomass, PAL activity, and the accumulation of phenolic acids and flavonoids in seedlings. Elevated CO{sub 2} concentration increased the activities of all the enzymes studied and the accumulation of condensed tannins in leaves, especially with UV-B radiation. Because the observed UV-B induction of flavonoids was smaller under a high CO{sub 2} concentration, it was suggested that the excess of carbon in the atmosphere may moderate the effect of UV-B by increasing the metabolic activity of leaves (high enzyme activities) and by changing the allocation of internal carbon between different primary and secondary metabolites in the

  4. Anthropogenic changes in the surface all-sky UV-B radiation through 1850–2005 simulated by an Earth system model

    Directory of Open Access Journals (Sweden)

    S. Watanabe

    2012-06-01

    Full Text Available The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280–315 nm radiation through 1850–2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and deforestation regions. Furthermore, changes in ozone transport in the lower stratosphere, which is induced by increasing greenhouse gas concentrations, increase ozone concentration in the extratropical upper troposphere and lower stratosphere. These transient changes work to decrease the amount of UV-B reaching the Earth's surface, counteracting the well-known effect increasing UV-B due to stratospheric ozone depletion, which developed rapidly after ca. 1980. As a consequence, the surface UV-B radiation change between 1850 and 2000 is negative in the tropics and NH extratropics and positive in the SH extratropics. Comparing the contributions of ozone and aerosol changes to the UV-B change, the transient change in ozone absorption of UV-B mainly determines the total change in the surface UV-B radiation at most locations. On the other hand, the aerosol direct and indirect effects on UV-B play an equally important role to that of ozone in the NH mid-latitudes and tropics. A typical example is East Asia (25° N–60° N and 120° E–150° E, where the effect of aerosols (ca. 70% dominates the total UV-B change.

  5. Phototherapy appliances, their ultraviolet radiation and quality assurance of phototherapy; Terveydenhuollon laadunhallinta. Valohoitolaitteet, niiden UV- saeteily ja valohoitojen laadunvarmistus

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Leszczynski, K.; Visuri, R.; Ylianttila, L.; Jokela, K. [Radiation and Nuclear Safety Authority, Helsinki (Finland)

    1998-12-31

    Artificial UV radiation (UVR) is used in the treatment of psoriasis and other skin diseases. Long term phototherapy is associated to increased risk of squamous cell carcinoma. This report gives a short review of biological effects of UVR and technical aspects of phototherapy units. The phototherapy units used in Finnish Central hospitals are described and the measured UVR dose rates of these units are presented. In addition, the UVR meters used in hospitals are described and the calibration factors are given for UVR dose rate measurements: Finally, recommendations are given for the quality assurance of photo-therapy units as well as for assessing UVR doses of patients. (orig.) 88 refs.

  6. Photosensitivity mechanism of undoped poly(methyl methacrylate) under UV radiation at 325 nm and its spatial resolution limit

    DEFF Research Database (Denmark)

    Sáez-Rodríguez, D.; Nielsen, Kristian; Bang, Ole

    2014-01-01

    In this Letter, we provide evidence suggesting that the main photosensitive mechanism of an undoped poly(methyl methacrylate)-based microstructured optical fiber under UV radiation at 325 nm is a competitive process of both photodegradation and polymerization. We found experimentally...... that increasing strain during photo-inscription leads to an increased photosensitivity, which is evidence of photodegradation. Likewise, refractive index change in the fiber was measured to be positive, which provides evidence for further polymerization of the material. Finally, we relate the data obtained...

  7. Electrolytic membrane formation of fluoroalkyl polymer using a UV-radiation-based grafting technique and sulfonation

    Energy Technology Data Exchange (ETDEWEB)

    Shironita, Sayoko; Mizoguchi, Satoko; Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata (Japan)

    2011-03-15

    A sulfonated fluoroalkyl graft polymer (FGP) membrane was prepared as a polymer electrolyte. First, the FGP membrane was grafted with styrene under UV irradiation. The grafted FGP was then sulfonated to functionalize it for proton conductivity. The grafting degree of the membrane increased with increasing grafting time during UV irradiation. The proton conductivity of the membrane increased with increasing grafting degree. The swelling ratio was independent of the grafting time, however, the water uptake increased with increasing grafting degree. Based on these results, it was found that the UV-initiated styrene grafting occurred along the membrane thickness direction. Moreover, the membrane was embedded within the glass fibers of the composite. This composite electrolytic membrane had 1.15 times the proton conductivity of a Nafion 117 membrane.

  8. UV-B absorbing compounds in present-day and fossil pollen, spores, cuticles seed coats and wood: evaluation of a proxy for solar UV-B radiation.

    NARCIS (Netherlands)

    Rozema, J.; Blokker, P.; Mayoral Fuertes, M.; Broekman, R.A.

    2009-01-01

    UV-B absorbing compounds (UACs) in present-day and fossil pollen, spores, cuticles, seed coats and wood have been evaluated as a proxy for past UV. This proxy may not only provide information on variation of stratospheric ozone and solar UV in the period preceding and during the Antarctic ozone hole

  9. UV radiation effects on a DNA repair enzyme: conversion of a [4Fe-4S](2+) cluster into a [2Fe-2S] (2+).

    Science.gov (United States)

    Folgosa, Filipe; Camacho, Inês; Penas, Daniela; Guilherme, Márcia; Fróis, João; Ribeiro, Paulo A; Tavares, Pedro; Pereira, Alice S

    2015-03-01

    Organisms are often exposed to different types of ionizing radiation that, directly or not, will promote damage to DNA molecules and/or other cellular structures. Because of that, organisms developed a wide range of response mechanisms to deal with these threats. Endonuclease III is one of the enzymes responsible to detect and repair oxidized pyrimidine base lesions. However, the effect of radiation on the structure/function of these enzymes is not clear yet. Here, we demonstrate the effect of UV-C radiation on E. coli endonuclease III through several techniques, namely UV-visible, fluorescence and Mössbauer spectroscopies, as well as SDS-PAGE and electrophoretic mobility shift assay. We demonstrate that irradiation with a UV-C source has dramatic consequences on the absorption, fluorescence, structure and functionality of the protein, affecting its [4Fe-4S] cluster and its DNA-binding ability, which results in its inactivation. An UV-C radiation-induced conversion of the [4Fe-4S](2+) into a [2Fe-2S](2+) was observed for the first time and proven by Mössbauer and UV-visible analysis. This work also shows that the DNA-binding capability of endonuclease III is highly dependent of the nuclearity of the endogenous iron-sulfur cluster. Thus, from our point of view, in a cellular context, these results strengthen the argument that cellular sensitivity to radiation can also be due to loss of radiation-induced damage repair ability.

  10. Short-term UV-B radiation and ozone exposure effects on aromatic secondary metabolite accumulation and shoot growth of flavonoid-deficient Arabidopsis mutants

    Energy Technology Data Exchange (ETDEWEB)

    Ormrod, D.P. [Univ. of Guelph, Dept. of HorticulturalScience, Guelph, On (Canada); Landry, L.G.; Conklin, P.L.; Thomson, B. [Cornell Univ., Institute for Plant Research, Ithaca, NY (United States)

    1995-05-01

    The presence of UV-absorptive substances in the epidermal cells of leaves is thought to protect mesophyll tissues from the harmful effects of UV-B radiation. We examined the influence of short-term UV-B exposures on UV-absorptive (330 nm) sinapates and flavonols, and on shoot growth of the Arabidopsis wild type ecotype Landsberg erecta and two mutants, tt4, deficient in chalcone synthase, and tt5, deficient inchalcone/flavonone isomerase. Sequential ozone exposures were used to determine the effects of oxidative stress. The levels of sinapates and flavonols on a leaf fresh weight basis increased substantially in the wild type and sinapates increased in the tt4 mutant, in vegetative, vegetative/reproductive transitional and reproductive stage plants in response to short-term (ei h) UV-B radiation. When UV-B was discontinued the levels generally decreased to pre-exposure levels after 48 h in vegetative/reproductive but not in reproductive plants. Exposure to ozone before or after UV-B treatment did not consistently affect the levels of the UV-absorptive compounds. Dry matter accumulation was less affected by UV-B at the vegetative and reproductive stages than at the vegetative/reproductive stage. At the vegatative/reproductive stage, shoot growth of all 3 genotypes was retarded by UV-B. Growth was not retarded by short-term ozone exposure alone but when exposure to ozone followed UV-B exposure, growth was reduced in all genotypes. Leaf cupping appeared on tt5 plants exposed to UV-B. (au) (25 refs.)

  11. Optical Communication among Oscillatory Reactions and Photo-Excitable Systems: UV and Visible Radiation Can Synchronize Artificial Neuron Models.

    Science.gov (United States)

    Gentili, Pier Luigi; Giubila, Maria Sole; Germani, Raimondo; Romani, Aldo; Nicoziani, Andrea; Spalletti, Anna; Heron, B Mark

    2017-06-19

    Neuromorphic engineering promises to have a revolutionary impact in our societies. A strategy to develop artificial neurons (ANs) is to use oscillatory and excitable chemical systems. Herein, we use UV and visible radiation as both excitatory and inhibitory signals for the communication among oscillatory reactions, such as the Belousov-Zhabotinsky and the chemiluminescent Orban transformations, and photo-excitable photochromic and fluorescent species. We present the experimental results and the simulations regarding pairs of ANs communicating by either one or two optical signals, and triads of ANs arranged in both feed-forward and recurrent networks. We find that the ANs, powered chemically and/or by the energy of electromagnetic radiation, can give rise to the emergent properties of in-phase, out-of-phase, anti-phase synchronizations and phase-locking, dynamically mimicking the communication among real neurons. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. UV radiation and natural fluorescence linked primary production in Antarctic waters

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; KrishnaKumari, L.; Bhattathiri, P.M.A.; Chandramohan, D.

    normalized for PAR, a more negative effect was noticed in the sub-surface and column waters and this negative effect was significant at 1 % level (p<0.01) in column waters. This response in the photosynthetic parameters could be due to the varied effect of UV...

  13. Inactivation of recombinant bacteriophage lambda by use of chemical agents and UV radiation.

    Science.gov (United States)

    Clark, Ewan M; Wright, Harry; Lennon, Kelly-Anne; Craik, Vicki A; Clark, Jason R; March, John B

    2012-04-01

    Several approaches for the inactivation of bacteriophage lambda, including UV germicidal irradiation (UVGI) and the chemical agents Virkon-S, Chloros, Decon-90, and sodium hydroxide (NaOH), were compared. Virkon, NaOH, and UVGI caused a ≥7-log(10) reduction in phage titers. This study successfully describes several methods with potential for bacteriophage inactivation in industrial settings.

  14. Mitotic recombination and inactivation in Saccharomyces cerevisiae induced by UV-radiation (254 nm) and hyperthermia depend on UV fluence rate.

    Science.gov (United States)

    Petin, V G; Kim, J K; Rassokhina, A V; Zhurakovskaya, G P

    2001-07-01

    In experiments with wild-type diploid yeast cells of Saccharomyces cerevisiae, the synergistic interaction of ultraviolet (UV) light (wavelength, 254 nm) and heat (45--60 degrees C) was studied both for mutagenic and inactivation effects. Simultaneous hyperthermia and UV light treatments increase the frequency of UV-induced mitotic intergenic recombination (crossing-over) and cell inactivation. The enhancing effect was a function of UV light fluence rate. It is concluded that the effect of hyperthermia on low fluence UV or high fluence UV irradiation results in comparable effects on survival and mitotic recombination suggesting similar modulation by hyperthermia of the effects induced by UV at different fluence rates. The interpretation of the data obtained was carried out within the widely accepted point of view considering the synergistic effects as a result of repair ability damage.

  15. Study of the effect of different type of aerosols on UV-B radiation from measurements during EARLINET

    Directory of Open Access Journals (Sweden)

    D. S. Balis

    2004-01-01

    Full Text Available Routine lidar measurements of the vertical distribution of the aerosol extinction coefficient and the extinction-to-backscatter ratio have been performed at Thessaloniki, Greece using a Raman lidar system in the frame of the EARLINET project since 2000. Co-located spectral and broadband solar UV-B irradiance measurements, as well as total ozone observations, were available whenever lidar measurements were obtained. From the available measurements several cases could be identified that allowed the study of the effect of different types of aerosol on the levels of the UV-B solar irradiance at the Earth's surface. The TUV radiative transfer model has been used to simulate the irradiance measurements, using total ozone and the lidar aerosol data as input. From the comparison of the model results with the measured spectra the effective single scattering albedo was determined using an iterative procedure, which has been verified against results from the 1998 Lindenberg Aerosol Characterization Experiment. It is shown that for the same aerosol optical depth and for the same total ozone values the UV-B irradiances at the Earth's surface can show differences up to 10%, which can be attributed to differences in the aerosol type. It is shown that the combined use of the estimated single scattering albedo and of the measured extinction-to-backscatter ratio leads to a better characterization of the aerosol type probed.

  16. 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.

  17. Seasonal variation in vitamin D levels in the Canterbury, New Zealand population in relation to available UV radiation.

    Science.gov (United States)

    Livesey, John; Elder, Peter; Ellis, M Jane; McKenzie, Richard; Liley, Ben; Florkowski, Chris

    2007-09-21

    The optimal plasma 25-hydroxyvitamin D (25(OH)D) concentration is probably >75 nmol/L but in temperate regions lower levels are common. Few studies report the intensity of solar ultraviolet (UV) radiation when 25(OH)D is measured. We measured plasma 25(OH)D and incident solar UVB radiation in Christchurch and modelled the relationship between them. 25(OH)D, total calcium (CaT), ionised calcium (CaI) and parathyroid hormone (PTH) were measured in healthy volunteers (119 female, 82 male; median age 45 years, range 18 to 83) between February and July 2004. Vitamin D-weighted UV energy measurements (dUV) for Christchurch were from the National Institute of Water and Atmospheric Research (NIWA) UV Atlas. In February 2004, 88% of 25(OH)D levels were below 75 nmol/L, increasing to 100% in June and July. Severe deficiency (<12.5 nmol/L) was found in 1.5% of subjects. From February to July, 25(OH)D and CaI fell and CaT rose (p<0.001,<0.01, and <0.001). There was a hyperbolic relationship between PTH and 25OHD while CaT and CaI correlated negatively with PTH (r=-0.30 and -0.33; both p<0.001). Monthly mean dUV intensity ranged from 10 kJ m-2 day-1 in Dec 2003 to 0.5 kJ m-2 day-1 in June 2004. Compartmental modelling estimated that a Christchurch person made 1200 IU/day of vitamin D in mid-summer but only 60 IU/day in midwinter. Daily supplements of 1450 or 2600 IU vitamin D3 are predicted to raise the annual minimum mean plasma 25(OH)D to 75 or 100 nmol/L respectively. Most Christchurch people are vitamin D deficient most of the time and a daily supplement of 2600 IU vitamin D3 would correct this.

  18. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    Directory of Open Access Journals (Sweden)

    O. Fridman

    2006-03-01

    Full Text Available The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A, 820(B, 1368(C and 1915(D Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure.

  19. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation.

    Science.gov (United States)

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice (Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m(-2) day(-1)) and elevated UV-B radiation (E, a 20% higher dose of UV-B than the reference, 14.4 kJ m(-2) day(-1)), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha(-1)), Si1 (sodium silicate, 100 kg SiO2 ha(-1)), Si2 (sodium silicate, 200 kg SiO2 ha(-1)), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha(-1)). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate (Pn), intercellular carbon dioxide (CO2) concentration (Ci), transpiration rate (Tr), stomatal conductivity (Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3%, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9%, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2%, respectively, but decreased Tr by 1.9-10.8%, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  20. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation

    Science.gov (United States)

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice ( Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m-2 day-1) and elevated UV-B radiation (E, a 20 % higher dose of UV-B than the reference, 14.4 kJ m-2 day-1), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha-1), Si1 (sodium silicate, 100 kg SiO2 ha-1), Si2 (sodium silicate, 200 kg SiO2 ha-1), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha-1). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate ( Pn), intercellular carbon dioxide (CO2) concentration ( Ci), transpiration rate ( Tr), stomatal conductivity ( Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3 %, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9 %, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2 %, respectively, but decreased Tr by 1.9-10.8 %, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  1. UV laser radiation alters the embryonic protein profile of adrenal-kidney-gonadal complex and gonadal differentiation in the lizard, Calotes Versicolor.

    Science.gov (United States)

    Khodnapur, Bharati S; Inamdar, Laxmi S; Nindi, Robertraj S; Math, Shivkumar A; Mulimani, B G; Inamdar, Sanjeev R

    2015-02-01

    To examine the impact of ultraviolet (UV) laser radiation on the embryos of Calotes versicolor in terms of its effects on the protein profile of the adrenal-kidney-gonadal complex (AKG), sex determination and differentiation, embryonic development and hatching synchrony. The eggs of C. versicolor, during thermo-sensitive period (TSP), were exposed to third harmonic laser pulses at 355 nm from a Q-switched Nd:YAG laser for 180 sec. Subsequent to the exposure they were incubated at the male-producing temperature (MPT) of 25.5 ± 0.5°C. The AKG of hatchlings was subjected to protein analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and to histology. The UV laser radiation altered the expression of the protein banding pattern in the AKG complex of hatchlings and it also affected the gonadal sex differentiation. SDS-PAGE of AKG of one-day-old hatchlings revealed a total of nine protein bands in the control group whereas UV laser irradiated hatchlings expressed a total of seven protein bands only one of which had the same Rf as a control band. The UV laser treated hatchlings have an ovotestes kind of gonad exhibiting a tendency towards femaleness instead of the typical testes. It is inferred that 355 nm UV laser radiation during TSP induces changes in the expression of proteins as well as their secretions. UV laser radiation had an impact on the gonadal differentiation pathway but no morphological anomalies were noticed.

  2. Investigating the Impact of UV Radiation on High-Altitude Shallow Lake Habitats, Life Diversity, and Life Survival Strategies: Clues for Mars' Past Habitability Potential?

    Science.gov (United States)

    Cabrol, A.; Grin, E. A.; Hock, A.; Kiss, A.; Borics, G.; Kiss, K.; Acs, E.; Kovacs, G.; Chong, G.; Demergasso, C.

    2004-01-01

    We present data and results from an ongoing project of astrobiological high-altitude expeditions investigating the highest and least explored perennial lakes on Earth in the Bolivian and Chilean Andes, including several volcanic crater lakes nearing and beyond 6,000 m in elevation. In the next five years, they will provide the first integrated long-term astrobiological characterization and monitoring of lacustrine environments and their biology for such altitude. These extreme lakes are natural laboratories. They provide the field data missing beyond 4,000 m to complete our understanding of terrestrial lakes and biota. Research on the effects of UV has been performed in lower altitude lakes and models of UV flux over time are being developed. Lakes showing a high content of dissolved organic material (DOM) shield organisms from UV. DOM acts as a natural sunscreen as it influences the water transparency, therefore is a determinant of photic zone depth. In sparsely vegetated alpine areas, lakes are clearer and offer less protection from UV to organisms living in the water. Transparent water and high UV irradiance may maximize the penetration and effect of UV radiation. Shallow-water communities in these lakes are particularly sensitive to UV radiation. The periphyton can live on various susbtrates. While on rocks, it includes immobile species that cannot seek low UV refuges unlike sediment-dwelling periphyton or alpine phytoflagellates which undergo vertical migration. Inhibition of algal photosynthesis by UV radiation has been documented in laboratory and showed that phytoplankton production is reduced by formation of nucleic acid lesions or production of peroxides and free oxygen radicals. of peroxides and free oxygen radicals. Our project is providing the field data that is missing from natural laboratories beyond 4,000 m and will complement the vision of the effects of UV on life and its adaptation modes (or lack thereof).

  3. [Combination effects of enhanced UV-B radiation and O3 stress on photosynthetic characteristics of winter wheat].

    Science.gov (United States)

    Zheng, You-Fei; Zhang, Jin-En; Wu, Rong-Jun; Liu, Rui-Na; Zhao, Ze; Hu, Cheng-Da; Xu, Wei-Min; Zhao, Chun-Xia; Yao, Juan

    2011-10-01

    Experiments were conducted under open-top-chambers conditions to assess the photosynthetic responses of wheat plants (Triticum aestivum L., YangMail6) to supplemental UV-B radiation (10%-10.9% higher then control group, T1) and enhanced ozone [(100 +/- 9) nmol x mol(-1), T2], separately and in combination (combination treatment, T3), making use of LCpro + Portable Photosynthesis System and DIVING-PAM Fluorometer to determine gas exchange and chlorophyll fluorescence parameters. Results indicated that P(n), G(s), T(r), P(m) and I(k) of T1, T2 and T3 treatments decreased significantly compared to CK (control group, natural air and UV-B radiant intensity condition), while there were no differences between T3 and T1 or T2 or both in major growth stages. UV-B fiercely inhibited the stomatal conductance and transpiration of plants, while T1 stimulated stomata opening and transpiration in jointing stage. Dark respiration (R(d)) of T1 was increased, while no significance difference was found between T2 and CK or T3 and CK in most stages. T1 and T2 reduced F(v)/F(m) value only in booting stage, while T3 was significant lower than CK except jointing stage. qP value declined significantly in treatments of T1, T2 and T3 as Compared to CK, with decreasing amplitude occurring in the order T3 > T1 > T2. NPQ, Y (NPQ), Y (NO) value of T1, T2 and T3 treatments increased significantly compared to CK, with maximum increasing amplitude occurring in the order T3 > T1 > T2, of which NPQ of T1 and T2 turned to decrease since filling stage, and T3 turned to decrease since flowering stage to a greater degree than T1 and T2. T1, T2 and T3 also caused significance reduction in Y (II), with reducing amplitude occurring in the order T3 > T1 > T2. Obviously, supplemental UV-B radiation and enhanced ozone caused a significant decrease in gas exchange capacity, maximum photochemical capacity and photosynthetic activity of winter wheat, and the photoprotective mechanism was damage, leading to

  4. Photosynthetic Performance of the Red Alga Pyropia haitanensis During Emersion, With Special Reference to Effects of Solar UV Radiation, Dehydration and Elevated CO2 Concentration.

    Science.gov (United States)

    Xu, Juntian; Gao, Kunshan

    2015-11-01

    Macroalgae distributed in intertidal zones experience a series of environmental changes, such as periodical desiccation associated with tidal cycles, increasing CO2 concentration and solar UVB (280-315 nm) irradiance in the context of climate change. We investigated how the economic red macroalga, Pyropia haitanensis, perform its photosynthesis under elevated atmospheric CO2 concentration and in the presence of solar UV radiation (280-400 nm) during emersion. Our results showed that the elevated CO2 (800 ppmv) significantly increased the photosynthetic carbon fixation rate of P. haitanensis by about 100% when the alga was dehydrated. Solar UV radiation had insignificant effects on the net photosynthesis without desiccation stress and under low levels of sunlight, but significantly inhibited it with increased levels of desiccation and sunlight intensity, to the highest extent at the highest levels of water loss and solar radiation. Presence of UV radiation and the elevated CO2 acted synergistically to cause higher inhibition of the photosynthetic carbon fixation, which exacerbated at higher levels of desiccation and sunlight. While P. haitanensis can benefit from increasing atmospheric CO2 concentration during emersion under low and moderate levels of solar radiation, combined effects of elevated CO2 and UV radiation acted synergistically to reduce its photosynthesis under high solar radiation levels during noon periods. © 2015 The American Society of Photobiology.

  5. Response of two cultivars of Phaseolus vulgaris L. (French beans) plants exposed to enhanced UV-B radiation under mountain ecosystem.

    Science.gov (United States)

    Raghuvanshi, Rashmi; Sharma, Rajesh Kumar

    2016-01-01

    Enhanced solar ultraviolet-B (UV-B) irradiance resulting from depletion in the ozone layer has the potential to cause detrimental effects on plants. Higher altitudes tend to receive higher doses of ambient UV-B radiation. The present study was carried out to assess the effects of enhanced UV-B (ambient + 10.2 kJ m(-2) day(-1)) radiation on two cultivars of Phaseolus vulgaris L. (cv. Pusa Himlata and Pusa Parvati) at growth, physiological, and biochemical levels grown under mountain ecosystem. The magnitudes of negative effects of enhanced UV-B radiation were found more in Pusa Parvati as compared to Pusa Himlata. Non-enzymatic (total phenolics and flavonoids content) and enzymatic antioxidants (superoxide dismutase, catalase, and peroxidase) were increased in both cultivars at both the ages of growth but increase was found more in Pusa Himlata as compared to Pusa Parvati. The study further showed that the economic yield of Pusa Himlata and Pusa Parvati was decreased by 14 and 44%, respectively, due to enhanced UV-B radiation. The higher decrease in the economic yield of Pusa Parvati depicted that increased amounts of total flavonoids content and stimulation of their antioxidant defense mechanism via increasing the activities of enzymatic antioxidants were not able to completely detoxify the produced reactive oxygen species under enhanced UV-B radiation and made it more sensitive to applied stress. From the present study, it can be concluded that enhanced UV-B radiation in the mountain areas of the Indian Himalayan Regions could be one of the environmental causes for lower yields of agricultural crops. Cultivation of P. vulgaris L. cv. Pusa Himlata should be promoted at higher altitudes of the Indian Himalayan Regions.

  6. Time-dependent effect of rutin on skin fibroblasts membrane disruption following UV radiation

    Directory of Open Access Journals (Sweden)

    Agnieszka Gęgotek

    2017-08-01

    In conclusion, highest skin fibroblasts membrane level of rutin occurred in 2–4 h following UVA/B-radiation results in its strongest effect on biomembrane structure and functions and cellular antioxidant system irrespective of the radiation type.

  7. Development of a safe ultraviolet camera system to enhance awareness by showing effects of UV radiation and UV protection of the skin (Conference Presentation)

    Science.gov (United States)

    Verdaasdonk, Rudolf M.; Wedzinga, Rosaline; van Montfrans, Bibi; Stok, Mirte; Klaessens, John; van der Veen, Albert

    2016-03-01

    The significant increase of skin cancer occurring in the western world is attributed to longer sun expose during leisure time. For prevention, people should become aware of the risks of UV light exposure by showing skin damage and the protective effect of sunscreen with an UV camera. An UV awareness imaging system optimized for 365 nm (UV-A) was develop using consumer components being interactive, safe and mobile. A Sony NEX5t camera was adapted to full spectral range. In addition, UV transparent lenses and filters were selected based on spectral characteristics measured (Schott S8612 and Hoya U-340 filters) to obtain the highest contrast for e.g. melanin spots and wrinkles on the skin. For uniform UV illumination, 2 facial tanner units were adapted with UV 365 nm black light fluorescent tubes. Safety of the UV illumination was determined relative to the sun and with absolute irradiance measurements at the working distance. A maximum exposure time over 15 minutes was calculate according the international safety standards. The UV camera was successfully demonstrated during the Dutch National Skin Cancer day and was well received by dermatologists and participating public. Especially, the 'black paint' effect putting sun screen on the face was dramatic and contributed to the awareness of regions on the face what are likely to be missed applying sunscreen. The UV imaging system shows to be promising for diagnostics and clinical studies in dermatology and potentially in other areas (dentistry and ophthalmology)

  8. How Extreme is TRAPPIST-1? A look into the planetary system’s extreme-UV radiation environment

    Science.gov (United States)

    Peacock, Sarah; Barman, Travis; Shkolnik, Evgenya L.

    2018-01-01

    The ultracool dwarf star TRAPPIST-1 hosts three earth-sized planets at orbital distances where water has the potential to exist in liquid form on the planets’ surface. Close-in exoplanets, such as these, become vulnerable to water loss as stellar XUV radiation heats and expands their upper atmospheres. Currently, little is known about the high-energy radiation environment around TRAPPIST-1. Recent efforts to quantify the XUV radiation rely on empirical relationships based on X-ray or Lyman alpha line observations and yield very different results. The scaling relations used between the X-ray and EUV emission result in high-energy irradiation of the planets 10-1000x greater than present day Earth, stripping atmospheres and oceans in 1 Gyr, while EUV estimated from Lyman alpha flux is much lower. Here we present upper-atmosphere PHOENIX models representing the minimum and maximum potential EUV stellar flux from TRAPPIST-1. We use GALEX FUV and NUV photometry for similar aged M stars to determine the UV flux extrema in an effort to better constrain the high-energy radiation environment around TRAPPIST-1.

  9. Oxidative stress and enzymatic scavenging of superoxide radicals induced by solar UV-B radiation in Ulva canopies from southern Spain

    Directory of Open Access Journals (Sweden)

    Kai Bischof

    2003-09-01

    Full Text Available The generation of reactive oxygen species (ROS and scavenging of the superoxide radical by superoxide dismutase (SOD was studied in mat-like canopies of the green macroalga Ulva rotundata Bliding in a tidal brine pond system in southern Spain. Artificial canopies were covered with different cut-off filters, generating different radiation conditions. ROS and SOD were assessed after three days of exposure. ROS induced lipid peroxidation depended on the position of individual thalli within the canopy and on radiation conditions. Samples exposed to the full solar spectrum were most affected, whereas samples either exposed to photosynthetically active radiation (PAR alone or UV radiation without PAR exhibited fewer peroxidation products. The activity of SOD appeared to be controlled by the impinging UV-A and UV-B radiation and also increased in response to oxidative stress. The results provide evidence for additive effects of high PAR and UV-B under field conditions and support the previously proposed hypothesis that UV-B effects are mediated by an inhibition of the xanthophyll cycle, which increases ROS production and, consequently, causes oxidative damage to components of the photosynthetic machinery, such as proteins and pigments.

  10. Effect of UV-A radiation as an environmental stress on the development, longevity, and reproduction of the oriental armyworm, Mythimna separata (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Ali, Arif; Rashid, Muhammad Adnan; Huang, Qiu Ying; Lei, Chao-Liang

    2016-09-01

    The ultraviolet light (UV-A) range of 320-400 nm is widely used as light trap for insect pests. Present investigation was aimed to determine the effect of UV light-A radiation on development, adult longevity, reproduction, and development of F1 generation of Mythimna separata. Our results revealed that the mortality of the second instar larvae was higher than the third and fourth instar larvae after UV-A radiation. As the time of UV-A irradiation for pupae prolonged, the rate of adult emergence reduced. Along with the extension of radiation time decreased the longevity of adult females and males. However, the radiation exposure of 1 and 4 h/day increased fecundity of female adults, and a significant difference was observed in a 1 h/day group. The oviposition rates of female adults in all the treatments were significantly higher than the control. In addition, UV-A radiation treatments resulted in declined cumulative survival of F1 immature stages (eggs, larvae, and pupae). After exposure time of 4 and 7 h/day, the developmental periods of F1 larvae increased significantly, but no significant effects on F1 pupal period were recorded.

  11. A genome-wide screen in Saccharomyces cerevisiae for genes affecting UV radiation sensitivity.

    Science.gov (United States)

    Birrell, G W; Giaever, G; Chu, A M; Davis, R W; Brown, J M

    2001-10-23

    The recent completion of the deletion of essentially all of the ORFs in yeast is an important new resource for identifying the phenotypes of unknown genes. Each ORF is replaced with a cassette containing unique tag sequences that allow rapid parallel analysis of strains in a pool by using hybridization to a high-density oligonucleotide array. We examined the utility of this system to identify genes conferring resistance to UV irradiation by using a pool of 4,627 individual homozygous deletion strains (representing deletions of all nonessential genes). We identified most of the nonessential genes previously shown to be involved in nucleotide excision repair, in cell cycle checkpoints, in homologous recombination, and in postreplication repair after UV damage. We also identified and individually confirmed, by replacing the genes, three new genes, to our knowledge not previously reported to confer UV sensitivity when deleted. Two of these newly identified genes have human orthologs associated with cancer, demonstrating the potential of this system to uncover human genes affecting sensitivity to DNA-damaging agents and genes potentially involved in cancer formation.

  12. Effect of grape bunch sunlight exposure and UV radiation on phenolics and volatile composition of Vitis vinifera L. cv. Pinot noir wine.

    Science.gov (United States)

    Song, Jianqiang; Smart, Richard; Wang, Hua; Dambergs, Bob; Sparrow, Angela; Qian, Michael C

    2015-04-15

    The effect of canopy leaf removal and ultraviolet (UV) on Pinot noir grape and wine composition was investigated in this study. Limited basal leaf removal in the fruit zone was conducted, compared to shaded bunches. The UV exposure was controlled using polycarbonate screens to block UV radiation, and acrylic screens to pass the UV. The results showed that bunch sunlight and UV exposure significantly increased the Brix and pH in the grape juice, and increased substantially wine colour density, anthocyanins, total pigment, total phenolics and tannin content. Bunch sunlight and UV exposure affected terpene alcohols, C13-norisprenoids and other volatile composition of the wine differently. Sunlight exposure and UV resulted in increase of nerol, geraniol and citronellol but not linalool. Sunlight exposure slightly increased the concentration of β-ionone, but the increase was not statistically significant for UV treatment. Neither sunlight nor UV treatment showed any impact on the concentration of β-damascenone. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Spectral variations of UV-A and PAR solar radiation in estuarine waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Talaulikar, M.; Suresh, T.; Silveira, N.; Desa, E.; Matondkar, S.G.P.; Lotlikar, A.

    The spectral solar radiation measurements in the range 350-800 nm were carried out in the estuarine waters of Goa using hyperspectral radiometer. The results of the analysis of solar light in the spectral range of photosynthetically available...

  14. Photosynthesis of two Arctic macroalgae under different ambient radiation levels and their sensitivity to enhanced UV radiation

    NARCIS (Netherlands)

    Brouwer, P.E.M.; Bischof, K.; Hanelt, D.; Kromkamp, J.C.

    2000-01-01

    The change in optimal quantum efficiency (F-v/F-m) of the Arctic species Laminaria saccharina and Palmaria palmata was investigated in a long-term experiment in situ under different radiation levels during the summer of 1997 in the Kongsfjord (Ny-Alesund, Spitsbergen, Norway, 78 degrees 55.5'N, 11

  15. Measurements of DNA Damage and Repair in Bacillus anthracis Sterne Spores by UV Radiation

    Science.gov (United States)

    2014-09-18

    John Wiley & Sons. When forming a spore, the cell dehydrates , binding its DNA securely with small, acid-soluble proteins (SASPs). The DNA is...but Not to Solar Radiation," Applied and Environmental Microbiology , vol. 62, no. 7, pp. 2221-2227, July 1996. [33] L. Yang, G. Lin, D. Liu, K. J... Solar Radiation," Applied and Environmental Microbiology, vol. 66, no. 2, pp. 620-626, November 2000. 122 [68] J. A. Sikorsky, D. A. Primerano

  16. Anthropogenic changes in the surface all-sky UV-B radiation through 1850–2005 simulated by an Earth system model

    OpenAIRE

    Yokohata, T.; Sudo, K; Takemura, T.; Watanabe, S.; Kawase, H.

    2012-01-01

    The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280–315 nm) radiation through 1850–2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial a...

  17. Anthropogenic changes in the surface all-sky UV-B radiation through 1850–2005 simulated by an Earth system model

    OpenAIRE

    Watanabe, S.; Takemura, T.; Sudo, K; Yokohata, T.; Kawase, H.

    2012-01-01

    The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280–315 nm) radiation through 1850–2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and defo...

  18. Projections of UV radiation changes in the 21st century: impact of ozone recovery and cloud effects

    Directory of Open Access Journals (Sweden)

    A. F. Bais

    2011-08-01

    Full Text Available Monthly averaged surface erythemal solar irradiance (UV-Ery for local noon from 1960 to 2100 has been derived using radiative transfer calculations and projections of ozone, temperature and cloud change from 14 chemistry climate models (CCM, as part of the CCMVal-2 activity of SPARC. Our calculations show the influence of ozone depletion and recovery on erythemal irradiance. In addition, we investigate UV-Ery changes caused by climate change due to increasing greenhouse gas concentrations. The latter include effects of both stratospheric ozone and cloud changes. The derived estimates provide a global picture of the likely changes in erythemal irradiance during the 21st century. Uncertainties arise from the assumed scenarios, different parameterizations – particularly of cloud effects on UV-Ery – and the spread in the CCM projections. The calculations suggest that relative to 1980, annually mean UV-Ery in the 2090s will be on average ~12 % lower at high latitudes in both hemispheres, ~3 % lower at mid latitudes, and marginally higher (~1 % in the tropics. The largest reduction (~16 % is projected for Antarctica in October. Cloud effects are responsible for 2–3 % of the reduction in UV-Ery at high latitudes, but they slightly moderate it at mid-latitudes (~1 %. The year of return of erythemal irradiance to values of certain milestones (1965 and 1980 depends largely on the return of column ozone to the corresponding levels and is associated with large uncertainties mainly due to the spread of the model projections. The inclusion of cloud effects in the calculations has only a small effect of the return years. At mid and high latitudes, changes in clouds and stratospheric ozone transport by global circulation changes due to greenhouse gases will sustain the erythemal irradiance at levels below those in 1965, despite the removal of ozone depleting substances. At northern high latitudes (60°–90°, the projected decreases in cloud

  19. Analysis of Photosynthetic Characteristics and UV-B Absorbing Compounds in Mung Bean Using UV-B and Red LED Radiation

    Directory of Open Access Journals (Sweden)

    Fang-Min Li

    2014-01-01

    Full Text Available Mung bean has been reported to have antioxidant, antidiabetic, anti-inflammatory, and antitumor activities. Various factors have important effects on the types and contents of plant chemical components. In order to study quality of mung bean from different light sources, mung bean seedlings were exposed to red light-emitting diodes (LEDs and ultraviolet-B (UV-B. Changes in the growth parameters, photosynthetic characteristics, the concentrations of chlorophyll a and chlorophyll b and the content of UV-B absorbing compounds were measured. The results showed that photosynthetic characteristics and chlorophyll a and chlorophyll b concentrations were enhanced by red LEDs. The concentrations of UV-B absorbing compounds were enhanced by UV-B on the 20th day, while photosynthetic characteristics, plant length, and the concentrations of chlorophyll a and chlorophyll b were reduced by UV-B on the 40th day; at the same time the values of the stem diameter, plant fresh weight, dry weight, and the concentrations of UV-B absorbing compounds were enhanced. It is suggested that red LEDs promote the elongation of plant root growth and photosynthetic characteristics, while UV-B promotes horizontal growth of stems and the synthesis of UV-B absorbing compounds.

  20. Photosynthetic characteristics and mycosporine-like amino acids under UV radiation: a competitive advantage of Mastocarpus stellatus over Chondrus crispus at the Helgoland shoreline?

    Science.gov (United States)

    Bischof, K.; Kräbs, G.; Hanelt, D.; Wiencke, C.

    2000-05-01

    Chondrus crispus and Mastocarpus stellatus both inhabit the intertidal and upper sublittoral zone of Helgoland, but with C. crispus generally taking a lower position. Measurements of chlorophyll fluorescence, activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), and content and composition of UV absorbing mycosporine-like amino acids (MAAs) were conducted in the laboratory, to test whether susceptibility to UV radiation may play a role in the vertical distribution of these two species. Effective and maximal quantum yield of photochemistry as well as maximal electron transport rate (ETRmax) in C. crispus were more strongly affected by UV-B radiation than in M. stellatus. In both species, no negative effects of the respective radiation conditions were found on total activity of RubisCO. Total MAA content in M. stellatus was up to 6-fold higher than in C. crispus and the composition of MAAs in the two species was different. The results indicate that, among others, UV-B sensitivity may be a factor restricting C. crispus to the lower intertidal and upper sublittoral zone, whereas M. stellatus is better adapted to UV radiation and is therefore more competitive in the upper intertidal zone.

  1. Cholesterol homeostasis and cell proliferation by mitogenic homologs: insulin, benzo-α-pyrene and UV radiation.

    Science.gov (United States)

    Pandey, Hemlata; Talukdar, Ayantika; Gangte, Jeremy S; Gupta, S Datta; Chandra, N C

    2017-11-03

    Low-Density Lipoprotein (LDL) is known to promote the unregulated proliferation of cells that is progression of cancer. We aimed to investigate the effect of mitogens on the expression of cell cycle proteins, nuclear cholesterol and cell proliferation. We observed that insulin and benzo-α-pyrene (BaP) induced the expression of Low-Density Lipoprotein receptor (LDLR) on HepG2 cells, thereby enhancing the uptake of LDL. The internalized LDL increased the concentration of cholesterol in the cytoplasm and nucleus of the cell. At the same time, insulin and BaP also stimulated the expression of cell cycle proteins viz., Cyclin E and Cdk2, and thus induced more incorporation of Bromodeoxyuridine (BrdU) in cultured cells indicating increased DNA synthesis. Increased expression of cell cycle proteins and DNA synthesis are the indications of DNA replication and new cell synthesis. This suggests a link between the enhanced nuclear cholesterol concentration and new cell formation. On the other hand, UV irradiation with selectively given dose of cell death eventually decreases nuclear cholesterol concentration and LDLR expression. Reduced LDLR shows low functional activity. This, again, repeated the plausibility of the same link between intracellular cholesterol concentration and cell population. The biasness of adverse effect observed by UV irradiation has been compromised by inactivating LDLR with anti-LDLR antibody, resulting in similar effects on Cyclin E expression in the cultured cells. Hence, we concluded that in all the conditions, LDLR expression was found to be a translational event of its transcription factor, SREBP-2, by the induction of insulin, BaP and UV irradiation.

  2. Increase of the photosensitivity of undoped poly(methylmethacrylate) under UV radiation at 325 nm

    DEFF Research Database (Denmark)

    Sáez-Rodríguez, D.; Nielsen, Kristian; Bang, Ole

    2014-01-01

    In this paper we report, for the first time to our knowledge, an increase of the photosensitivity of a microstructured polymer optical fibre (mPOF) made of undoped PMMA due to applied strain during the fabrication of the gratings. In the work, fibre Bragg gratings (FBGs) have been fabricated...... in undoped PMMA mPOFs with a hexagonal structure of three rings in the inner cladding. Two sets of FBGs were inscribed at two different resonant wavelengths (827 nm and 1562 nm) at different strains using an UV He-Cd laser at 325 nm focused by a lens and scanned over the fibre. We observed an increase...

  3. Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

    DEFF Research Database (Denmark)

    Pereira, L.; Pospori, A.; Antunes, Paulo

    2017-01-01

    for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly during the grating inscription process by placing a narrow blocking aperture in the center of the UV beam. The produced high...... a significant increase in measurement resolution compared to direct interrogation of a single grating. The reflection and transmission spectra when multiple phase shifts are introduced in the FBG structure are also shown. The PS-POFBG's strain, temperature, pressure, and humidity characteristics have been...

  4. Repetitively pulsed UV radiation source based on a run-away electron preionised diffuse discharge in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Baksht, E Kh; Burachenko, A G; Lomaev, M I; Panchenko, A N; Tarasenko, V F [Institute of High Current Electronics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation)

    2015-04-30

    An extended repetitively pulsed source of spontaneous UV radiation is fabricated, which may also be used for producing laser radiation. Voltage pulses with an incident wave amplitude of up to 30 kV, a half-amplitude duration of ∼4 ns and a rise time of ∼2.5 ns are applied to a gap with a nonuniform electric field. For an excitation region length of 35 cm and a nitrogen pressure of 30 – 760 Torr, a diffusive discharge up to a pulse repetition rate of 2 kHz is produced without using an additional system for gap preionisation. An investigation is made of the plasma of the run-away electron preionised diffuse discharge. Using a CCD camera it is found that the dense diffused plasma fills the gap in a time shorter than 1 ns. X-ray radiation is recorded from behind the foil anode throughout the pressure range under study; a supershort avalanche electron beam is recorded by the collector electrode at pressures below 100 Torr. (laser applications and other topics in quantum electronics)

  5. Repetitively pulsed UV radiation source based on a run-away electron preionised diffuse discharge in nitrogen

    Science.gov (United States)

    Baksht, E. Kh; Burachenko, A. G.; Lomaev, M. I.; Panchenko, A. N.; Tarasenko, V. F.

    2015-04-01

    An extended repetitively pulsed source of spontaneous UV radiation is fabricated, which may also be used for producing laser radiation. Voltage pulses with an incident wave amplitude of up to 30 kV, a half-amplitude duration of ~4 ns and a rise time of ~2.5 ns are applied to a gap with a nonuniform electric field. For an excitation region length of 35 cm and a nitrogen pressure of 30 - 760 Torr, a diffusive discharge up to a pulse repetition rate of 2 kHz is produced without using an additional system for gap preionisation. An investigation is made of the plasma of the run-away electron preionised diffuse discharge. Using a CCD camera it is found that the dense diffused plasma fills the gap in a time shorter than 1 ns. X-ray radiation is recorded from behind the foil anode throughout the pressure range under study; a supershort avalanche electron beam is recorded by the collector electrode at pressures below 100 Torr.

  6. Effects of UV-B radiation on leaf hair traits of invasive plants-Combining historical herbarium records with novel remote sensing data.

    Directory of Open Access Journals (Sweden)

    Tomáš Václavík

    Full Text Available Ultraviolet-B (UV-B radiation is a key but under-researched environmental factor that initiates diverse responses in plants, potentially affecting their distribution. To date, only a few macroecological studies have examined adaptations of plant species to different levels of UV-B. Here, we combined herbarium specimens of Hieracium pilosella L. and Echium vulgare L. with a novel UV-B dataset to examine differences in leaf hair traits between the plants' native and alien ranges. We analysed scans of 336 herbarium specimens using standardized measurements of leaf area, hair density (both species and hair length (H. pilosella only. While accounting for other bioclimatic variables (i.e. temperature, precipitation and effects of herbivory, we examined whether UV-B exposure explains the variability and geographical distribution of these traits in the native (Northern Hemisphere vs. the alien (Southern Hemisphere range. UV-B explained the largest proportion of the variability and geographical distribution of hair length in H. pilosella (relative influence 67.1%, and hair density in E. vulgare (66.2%. Corresponding with higher UV-B, foliar hairs were 25% longer for H. pilosella and 25% denser for E. vulgare in records from the Southern as compared to those from the Northern Hemisphere. However, focusing on each hemisphere separately or controlling for its effect in a regression analysis, we found no apparent influence of UV-B radiation on hair traits. Thus, our findings did not confirm previous experimental studies which suggested that foliar hairs may respond to higher UV-B intensities, presumably offering protection against detrimental levels of radiation. We cannot rule out UV-B radiation as a possible driver because UV-B radiation was the only considered variable that differed substantially between the hemispheres, while bioclimatic conditions (e.g. temperature, precipitation and other considered variables (herbivory damage, collection date were at

  7. ROS and calcium signaling mediated pathways involved in stress responses of the marine microalgae Dunaliella salina to enhanced UV-B radiation.

    Science.gov (United States)

    Zhang, Xinxin; Tang, Xuexi; Wang, Ming; Zhang, Wei; Zhou, Bin; Wang, You

    2017-08-01

    UV-B ray has been addressed to trigger common metabolic responses on marine microalgae, however, the upstream events responsible for these changes in marine microalgae are poorly understood. In the present study, a species of marine green microalgae Dunaliella salina was exposed to a series of enhanced UV-B radiation ranging from 0.25 to 1.00 KJ·m -2 per day. The role of ROS and calcium signaling in the D. salina responses to UV-B was discussed. Results showed that enhanced UV-B radiation markedly decreased the cell density in a dose-dependent manner, but the contents of protein and glycerol that were essential for cell growth increased. It suggested that it was cell division instead of cell growth that UV-B exerted negative effects on. The subcellular damages on nuclei and plasmalemma further evidenced the hypothesis. The nutrient absorption was affected with UV-B exposure, and the inhibition on PO 4 3- uptake was more serious compared to NO 3 - uptake. UV-B radiation promoted reactive oxygen species (ROS) formation and thiobarbituric acid reactive substances (TBARS) contents, decreased the redox status and altered the antioxidant enzyme activities. The addition of the ROS scavenger and the glutathione biosynthesis precursor N-acetyl-l-cysteine (NAC) alleviated the stress degree, implying ROS-mediated pathway was involved in the stress response to UV-B radiation. Transient increase in Ca 2+ -ATPase was triggered simultaneously with UV-B exposure. Meanwhile, the addition of an intracellular free calcium chelator aggravated the damage of cell division, but exogenous calcium and ion channel blocker applications did not, inferring that endogenously initiated calcium signaling played roles in response to UV-B. Cross-talk analysis showed a relatively clear relationship between ROS inhibition and Ca 2+ -ATPase suppression, and a relation between Ca 2+ inhibition and GPx activity change was also observed. It was thus presumed that ROS-coupled calcium signaling via the

  8. Ag-Ag2S/reduced graphene oxide hybrids used as long-wave UV radiation emitting nanocomposites

    Science.gov (United States)

    Li, Wenyao; Xu, Ruoyu; Ling, Min; He, Guanjie

    2017-10-01

    We report a facile thermal decomposition approach to synthesize Ag-Ag2S/reduced graphene oxide (Ag-Ag2S/rGO), the Ag-Ag2S nanoparticles uniformly dispersed on reduced graphene oxide with diameters of 10-20 nm. The photoluminescence spectra of Ag-Ag2S/rGO showed two obvious emission peaks at 327 and 339 nm with the excitation wavelength at 287 nm. Compared with Ag-Ag2S heterostructured clusters with two peaks at 407 and 430 nm, it showed a big blue shift and higher intensity, which makes it a novel candidate for long-wave UV radiation emitting nanocomposite.

  9. Monitoring the solar UV-B radiation in the North of Munich: A comparison of two sites

    Science.gov (United States)

    Albert, Andreas; Rupprecht, Werner; Mayer, Ingo; Steinmetz, Manfred; Seidlitz, Harald K.; Thiel, Stephan

    2013-05-01

    Since 2008, measurements of the downwelling solar spectral irradiance from 290 to 400 nm were compared at two field sites at Neuherberg, north of Munich, Germany, 11.6 E, 48.22 N, 490 m above sea level: (1) Research Unit Environmental Simulation (EUS) at the Helmholtz Zentrum München (former GSF National Reasearch Center for Environment and Health), (2) Federal Office for Radiation Protection (BfS). The spectral measurements of two double monochromator systems (TDM300, Bentham, Reading, UK) at 11:00 GMT were analyzed every day. Spectral comparison showed no misalignment of the wavelength calibration. The mean deviation of 1090 measurements at three different wavelengths in the UV-B range (280 - 315 nm) showed coefficients of determination better than 0.94 and a 10% higher value of spectral irradiance of the EUS system, mainly due to different entrance optics and spectral resolution.

  10. [Effect of UV-B radiation on release of nitrogen and phosphorus from leaf litter in subtropical region in China].

    Science.gov (United States)

    Song, Xin-Zhang; Zhang, Hui-Ling; Jiang, Hong; Yu, Shu-Quan

    2012-02-01

    The release of nitrogen and phosphorus from leaf litter of six representative species, Cunninghamia lanceolata, Pinus massoniana, Schima superba, Cinnamanun camphora, Cyclobalanopsis glauca and Castanopsis eyeri, was investigated with litterbag method under ambient and reduced UV-B radiation (22.1% below ambient) treatments in subtropical region. The results showed that, the N dynamics exhibited three patterns: immobilization, mineralization-immobilization and mineralization-immobilization-mineralization. P dynamics also exhibited three different patterns: mineralization, immobilization-mineralization-immobilization and no large change. Compared with ambient treatment, the reduced treatment significantly delayed the N release from C. eyeri and P release from both C. glanca and C. eyeri (Pradiation in the forest ecosystem in humid subtropical China under global environment change.

  11. Influence of solar UV radiation on the nitrogen metabolism in needles of Scots pine (Pinus sylvestris L.).

    Science.gov (United States)

    Krywult, Marek; Smykla, Jerzy; Kinnunen, Heli; Martz, Françoise; Sutinen, Marja-Liisa; Lakkala, Kaisa; Turunen, Minna

    2008-12-01

    Needles of 20-year-old Scots pine (Pinus sylvestris L.) saplings were studied in an ultraviolet (UV) exclusion field experiment (from 2000 to 2002) in northern Finland (67 degrees N). The chambers held filters that excluded both UV-B and UV-A, excluded UV-B only, transmitted all UV (control), or lacked filters (ambient). UV-B/UV-A exclusion decreased nitrate reductase (NR) activity of 1-year-old needles of Scots pines compared to the controls. The proportion of free amino acids varied in the range 1.08-1.94% of total proteins, and was significantly higher in needles of saplings grown under UV-B/UV-A exclusion compared to the controls or UV-B exclusion. NR activity correlated with air temperature, indicating a "chamber effect". The study showed that both UV irradiance and increasing temperature are significant modulators of nitrogen (N) metabolism in Scots pine needles.

  12. Effects of solar UV-B radiation on canopy structure of Ulva communities from southern Spain

    NARCIS (Netherlands)

    Bischof, K; Peralta, G; Krabs, G; van de Poll, WH; Perez-Llorens, JL; Breeman, AM

    2002-01-01

    Within the sheltered creeks of Cadiz bay, Ulva thalli form extended mat-like canopies. The effect of solar ultraviolet radiation on photosynthetic activity, the composition of photosynthetic and xanthophyll cycle pigments, and the amount of RubisCO, chaperonin 60 (CPN 60), and the induction of DNA

  13. Outflows in massive star forming regions: UV radiation and shocked cavity walls toward AFGL 2591

    NARCIS (Netherlands)

    Doty, Steven; Rogers, Noah; Doty, Sandra; van der Tak, Floris; van Dishoeck, Ewine

    Outflows can play an important role in regulating the star formation process. These outflows have the potential to deposit significant energy to large distances from the protostar through material motion and shocks, as well as via radiation through the subsequent outflow cavity. Herschel

  14. Observation of two-photon absorption at UV radiation in ZnS ...

    Indian Academy of Sciences (India)

    2014-02-12

    YAG laser radiation having pulsed duration of 10 ns with the repetition rate of 10 Hz. The measured experimental data have been analysed by using analytical models and two-photon absorption coefficients of the ZnS QDs at ...

  15. Characterization of dry globular proteins and protein fibrils by synchrotron radiation vacuum UV circular dichroism

    DEFF Research Database (Denmark)

    Nesgaard, Lise; Hoffmann, Søren V.; Andersen, Christian Beyschau

    2008-01-01

    Circular dichroism using synchrotron radiation (SRCD) can extend the spectral range down to approximately 130 nm for dry proteins, potentially providing new structural information. Using a selection of dried model proteins, including alpha-helical, beta-sheet, and mixed-structure proteins, we obs...

  16. Anti-UV Radiation Textiles Designed by Embracing with Nano-MIL (Ti, In)-Metal Organic Framework.

    Science.gov (United States)

    Emam, Hossam E; Abdelhameed, Reda M

    2017-08-23

    Protective textiles against harmful solar radiation are quite important materials for outdoor workers to secure their skin from several diseases. Current report focuses on production of anti-ultraviolet radiation (UVR) textiles by incorporation of nano-metal-organic frameworks (n-MOFs). Two different MIL-MOFs, namely, MIL-68(In)-NH2 and MIL-125(Ti)-NH2, were immediately formed inside natural textiles (cotton and silk) matrix in nano size using quite simple and one-pot process. The formation of n-MIL-MOFs inside textiles were confirmed by using electron microscope and X-ray diffraction. Different size and morphology were seen depending on textile type reflecting the textiles' chemical composition role in the nature of prepared MIL-MOFs. For MIL-68(In)-NH2, particles with size distribution of 70.6-44.5 nm in cotton and 81.3-52.2 nm in silk were detected, while crystalline disc of MIL-125(Ti)-NH2 was clearly seen inside textiles. The natural textiles exhibited full UVR blocking after modification, and the UV protection factor (UPF) was linearly proportional with MIL-MOFs and metal contents. Whatever metal type, direct incorporation of MIL-MOF contents greater than or equal to 10.4 g/kg was sufficient to attain excellent UV blocking property. Although 38.5-41.0% of MIL-MOFs was lost during five washings, the washed samples showed very good blocking rate (UPF = 26.7-36.2) supporting good laundering durability.

  17. Development and evaluation of sunscreen creams containing morin-encapsulated nanoparticles for enhanced UV radiation protection and antioxidant activity.

    Science.gov (United States)

    Shetty, Pallavi Krishna; Venuvanka, Venkatesh; Jagani, Hitesh Vitthal; Chethan, Gejjalagere Honnappa; Ligade, Virendra S; Musmade, Prashant B; Nayak, Usha Y; Reddy, Meka Sreenivasa; Kalthur, Guruprasad; Udupa, Nayanabhirama; Rao, Chamallamudi Mallikarjuna; Mutalik, Srinivas

    2015-01-01

    The objective of present work was to develop novel sunscreen creams containing polymeric nanoparticles (NPs) of morin. Polymeric NPs containing morin were prepared and optimized. The creams containing morin NPs were also prepared and evaluated. Optimized NPs exhibited particle size of 90.6 nm and zeta potential of -31 mV. The entrapment efficiency of morin, within the polymeric NPs, was found to be low (12.27%). Fourier transformed infrared spectroscopy and differential scanning calorimetry studies revealed no interaction between morin and excipients. Transmission electron microscopy and atomic force microscopy revealed that the NPs were spherical in shape with approximately 100 nm diameter. Optimized NPs showed excellent in vitro free radical scavenging activity. Skin permeation and deposition of morin from its NPs was higher than its plain form. Different sunscreen creams (SC1-SC8) were formulated by incorporating morin NPs along with nano zinc oxide and nano titanium dioxide. SC5 and SC8 creams showed excellent sun protection factor values (≈40). In vitro and in vivo skin permeation studies of sunscreen creams containing morin NPs indicated excellent deposition of morin within the skin. Morin NPs and optimized cream formulations (SC5 and SC8) did not exhibit cytotoxicity in Vero and HaCaT cells. Optimized sunscreen creams showed excellent dermal safety. SC5 and SC8 creams demonstrated exceptional in vivo antioxidant effect (estimation of catalase, superoxide dismutase, and glutathione) in UV radiation-exposed rats. The optimized sunscreen creams confirmed outstanding UV radiation protection as well as antioxidant properties.

  18. Comparison of TOMS retrievals and UVMRP measurements of surface spectral UV radiation in the United States

    Directory of Open Access Journals (Sweden)

    M. Xu

    2010-09-01

    Full Text Available Surface noontime spectral ultraviolet (UV irradiances during May-September of 2000–2004 from the total ozone mapping spectrometer (TOMS satellite retrievals are systematically compared with the ground measurements at 27 climatological sites maintained by the USDA UV-B Monitoring and Research Program. The TOMS retrievals are evaluated by two cloud screening methods and local air quality conditions to determine their bias dependencies on spectral bands, cloudiness, aerosol loadings, and air pollution. Under clear-sky conditions, TOMS retrieval biases vary from −3.4% (underestimation to 23.6% (overestimation. Averaged over all sites, the relative mean biases for 305, 311, 325, and 368 nm are respectively 15.4, 7.9, 7.6, and 7.0% (overestimation. The bias enhancement for 305 nm by approximately twice that of other bands likely results from absorption by gaseous pollutants (SO2, O3, and aerosols that are not included in the TOMS algorithm. For all bands, strong positive correlations of the TOMS biases are identified with aerosol optical depth, which explains nearly 50% of the variances of TOMS biases. The more restrictive in-situ cloud screening method reduces the biases by 3.4–3.9% averaged over all sites. This suggests that the TOMS biases from the in-situ cloud contamination may account for approximately 25% for 305 nm and 50% for other bands of the total bias. The correlation coefficients between total-sky and clear-sky biases across 27 sites are 0.92, 0.89, 0.83, and 0.78 for 305, 311, 325, and 368 nm, respectively. The results show that the spatial characteristics of the TOMS retrieval biases are systematic, representative of both clear and total-sky conditions.

  19. 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

  20. Effect of ZnO nano in the blend PET / PC ( 80/20) subjected to UV radiation; Efeito do nano ZnO na mistura PET/PC(80/20) submetida a radiacao UV

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Homero M.; Mendes, Luis C.; Albitres, Gerson A.V.; Cestari, Sibele P.; Mattos, Gabriela C., E-mail: homero@ima.ufrj.br [Universidade Federal do Rio de Janeiro (IMA/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Macromoleculas Professora Eloisa Mano

    2015-07-01

    The aim of this research was to reuse recycled poly(ethylene terephthalate) (PET) in blend with polycarbonate (PC) in order to avoid UV degradation in outdoor application. Nanocomposite based on blend of recycled (PET) and polycarbonate (PC) in the ratio of 80/20 with nano zinc oxide (ZnO) at different concentrations was prepared. The blend was subjected to ultraviolet (UV) radiation for accelerated aging chamber, we evaluated the effect of the presence nZnO filler as a barrier to UV rays. Dynamic-mechanical analysis (DMA) and nuclear magnetic resonance in the solid state (NMR). It is the degradation retardant effect at concentrations starting from 3% nZnO. (author)

  1. Re-interpreting plant morphological responses to UV-B radiation

    Czech Academy of Sciences Publication Activity Database

    Matthew Robson, T.; Klem, Karel; Urban, Otmar; Jansen, M. A.

    2015-01-01

    Roč. 38, č. 5 (2015), s. 856-866 ISSN 0140-7791 R&D Projects: GA MŠk LD12030 Institutional support: RVO:67179843 Keywords : auxin homeostasis * canopy structure and light interception * chronic * acute stress * flavonoid accumulation * plant-plant interactions * stress-induced morphogenic responses (SIMR) * ultraviolet radiation * UVR8 photoreceptor * whole-plant phenotype Subject RIV: EH - Ecology, Behaviour Impact factor: 6.169, year: 2015

  2. Studies of Collisional and Nonlinear Radiative Processes for Development of Coherent UV and XUV Sources

    Science.gov (United States)

    1991-06-04

    Production of Vacuum Ultraviolet Radiation in the Rare Gases," J. Opt. Soc. Am. B 4, 595 (1987). 76. R. Rosman . G. Gibson, K. Boyer, H. Jara, T. S. Luk...R. Rosman , T. S. Luk, I. A. McIntyre, A. McPherson, G. Wendin, K. Boyer, and C. K. Rhodes, "Characteristics of a Non-Equilibrium Picosecond Laser...A. C. Wahl, "Molecular Orbital Densities: Pictorial Studies, Comparisons of the Hydrogen, Lithium , Boron, Carbon, Nitrogen, Oxygen, and Fluorine

  3. Effects of solar PAR and UV radiation on tropical biofouling communities

    KAUST Repository

    Dobretsov, SV

    2010-03-08

    We investigated the effect of solar ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) on the development of tropical micro- and macrofouling communities for 30 d. The experimental design involved 3 treatments: full spectrum (PAR+UVR), PAR only, and minimal light (reduced PAR and UVR). Terminal restriction fragment length polymorphism analysis demonstrated that different light conditions resulted in the formation of highly different microbial communities. The lowest densities of bacteria were found under the full spectrum treatment, while the lowest densities of diatoms were found in the minimal light treatment. Macrofouling communities consisted of 13 species and differed among light treatments. In the presence of UVR, communities had low species diversity, evenness, and richness, while in minimal light and PAR treatments, communities had high species diversity, evenness, and richness. Similarity percentage (SIMPER) analysis revealed that the tubeworm Hydroides elegans, the alga Ulva (Enteromorpha) sp., and the bivalve Perna viridis were the species responsible for most of the dissimilarities in macrofouling communities among treatments. While densities of H. elegans were similar in the PAR and minimal light treatments, this polychaete had higher growth rates under minimal light conditions. We conclude that UVR and PAR directly control the development of shallow micro- and macrofouling communities by inhibiting the recruitment and growth of sensitive species and promoting the growth of resistant species, but also that these forms of solar radiation influence the surface cues available to competent larvae by altering the development of the microbial community.

  4. UV and IR laser radiation's interaction with metal film and teflon surfaces

    Science.gov (United States)

    Fedenev, A. V.; Alekseev, S. B.; Goncharenko, I. M.; Koval', N. N.; Lipatov, E. I.; Orlovskii, V. M.; Shulepov, M. A.; Tarasenko, V. F.

    2003-04-01

    The interaction of Xe ([lambda] [similar] 1.73 [mu]m) and XeCl (0.308 [mu]m) laser radiation with surfaces of metal and TiN-ceramic coatings on glass and steel substrates has been studied. Correlation between parameters of surface erosion versus laser-specific energy was investigated. Monitoring of laser-induced erosion on smooth polished surfaces was performed using optical microscopy. The correlation has been revealed between characteristic zones of thin coatings damaged by irradiation and energy distribution over the laser beam cross section allowing evaluation of defects and adhesion of coatings. The interaction of pulsed periodical CO2 ([lambda] [similar] 10.6 [mu]m), and Xe ([lambda] [similar] 1.73 [mu]m) laser radiation with surfaces of teflon (polytetrafluoroethylene—PTFE) has been studied. Monitoring of erosion track on surfaces was performed through optical microscopy. It has been shown that at pulsed periodical CO2-radiation interaction with teflon the sputtering of polymer with formation of submicron-size particles occurs. Dependencies of particle sizes, form, and sputtering velocity on laser pulse duration and target temperature have been obtained.

  5. Egg hatching response to a range of ultraviolet-B (UV-B) radiation doses for four predatory mites and the herbivorous spider mite Tetranychus urticae.

    Science.gov (United States)

    Koveos, Dimitrios S; Suzuki, Takeshi; Terzidou, Anastasia; Kokkari, Anastasia; Floros, George; Damos, Petros; Kouloussis, Nikos A

    2017-01-01

    Egg hatchability of four predatory mites-Phytoseiulus persimilis Athias-Henriot, Iphiseius [Amblyseius] degenerans Berlese, Amblyseius swirskii Athias-Henriot, and Euseius finlandicus Oudemans (Acari: Phytoseiidae)-and the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) was determined under various UV-B doses either in constant darkness (DD) or with simultaneous irradiation using white light. Under UV-B irradiation and DD or simultaneous irradiation with white light, the predator's eggs hatched in significantly lower percentages than in the control non-exposed eggs, which indicates deleterious effects of UV-B on embryonic development. In addition, higher hatchability percentages were observed under UV-B irradiation and DD in eggs of the predatory mites than in eggs of T. urticae. This might be caused by a higher involvement of an antioxidant system, shield effects by pigments or a mere shorter duration of embryonic development in predatory mites than in T. urticae, thus avoiding accumulative effects of UV-B. Although no eggs of T. urticae hatched under UV-B irradiation and DD, variable hatchability percentages were observed under simultaneous irradiation with white light, which suggests the involvement of a photoreactivation system that reduces UV-B damages. Under the same doses with simultaneous irradiation with white light, eggs of T. urticae displayed higher photoreactivation and were more tolerant to UV-B than eggs of the predatory mites. Among predators variation regarding the tolerance to UV-B effects was observed, with eggs of P. persimilis and I. degenerans being more tolerant to UV-B radiation than eggs of A. swirskii and E. finlandicus.

  6. Foraging behavior of honey bees (hymenoptera: Apidae) on Brassica nigra and B. rapa grown under simulated ambient and enhanced UV-B radiation

    Energy Technology Data Exchange (ETDEWEB)

    Collins, S.A.; Robinson, G.E. [Univ. of Illinois, Urbana, IL (United States); Conner, J.K. [Univ. of Illinois, Champaign, IL (United States)

    1997-01-01

    Two species of mustard, Brassica nigra and B. rapa, were grown under simulated ambient and enhanced ultraviolet-B (UV-B) radiation and exposed to pollinators, Apis mellifera L. Observations were made to determine whether UV-B-induced changes in these plants affected pollinator behavior. Total duration of the foraging trip, number of flowers visited, foraging time per flower, search time per flower, total amount of pollen collected, and pollen collected per flower were measured. There were no significant differences between UV-B treatments in any of the behaviors measured or in any of the pollen measurements. These results suggest that increases in the amount of solar UV-B reaching the earth`s surface may not have a negative effect on the relationship between these members of the genus Brassica and their honey bee pollinators. 28 refs., 2 figs., 1 tab.

  7. Effects of ambient versus reduced UV-B radiation on high arctic Salix arctica assessed by measurements and calculations of chlorophyll-a fluorescence parameters from fluorescence transients

    DEFF Research Database (Denmark)

    Albert, Kristian Rost

    2005-01-01

    A UV-B exclusion-experiment was conducted in the high arctic Zackenberg, NE Greenland, in which Salix arctica leaves during most of the growing season were fixed perpendicular to the solar zenith angle, thereby receiving maximal solar radiation. Covered with Teflon and Mylar foil, the leaves...... of evaluating the relative importance of UV-B of donor and acceptor side capacity in Photosystem II. In conclusion, the experimental set-up and non-invasive measurements proved to be a sensitive method to screen for effects of UV-B stress....... received approximately 90 and 40% of the ambient UV-B irradiance, respectively. The effects were examined through recordings of chlorophyll a fluorescence transients, determination of biomass and analysis of total carbon and nitrogen content and amount of soluble flavonoids in the leaves. The processing...

  8. Flavonoid concentrations in three grass species and a sedge grown in the field and under controlled environment conditions in response to enhanced UV-B radiation.

    NARCIS (Netherlands)

    van de Staaij, J.W.M.; Bakker, N.; Oosthoek, A.; Broekman, R.A.; van Beem, A.P.; Stroetenga, M.J.; Aerts, R.; Rozema, J.

    2002-01-01

    An investigation was carried out to find whether enhanced levels of UV-B radiation induce increased concentrations of flavonoids in the leaves of the grass species Deschampsia antarctica, Deschampsia borealis and Calamagrostis epigeios and the sedge Carex arenaria. Whether the enhanced levels of

  9. The effect of the operation modes of a gas discharge low-pressure amalgam lamp on the intensity of generation of 185 nm UV vacuum radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru [Russian Academy of Sciences, Joint Institute of High Temperatures (Russian Federation); Drozdov, L. A., E-mail: lit@npo.lit.ru; Kostyuchenko, S. V.; Sokolov, D. V. [ZAO LIT (Russian Federation); Kudryavtsev, N. N.; Sobur, D. A., E-mail: soburda@gmail.com [Moscow Institute for Physics and Technology (Russian Federation)

    2011-12-15

    The effect of the discharge current, mercury vapor pressure, and the inert gas pressure on the intensity and efficiency of the 185 nm line generation are considered. The spectra of the UV radiation (vacuum ultraviolet) transmission by protective coatings from the oxides of rare earth metals and aluminum are investigated.

  10. Wavelength-dependent induction of UV absorbing mycosporine-like amino acids in the red alga Chondrus crispus under natural solar radiation

    NARCIS (Netherlands)

    Krabs, G; Bischof, K; Hanelt, D; Karsten, U; Wiencke, C

    2002-01-01

    Polychromatic response spectra for the induction of UV absorbing mycosporine-like amino acids (MAAs) were calculated after exposing small thalli of the red alga Chondrus crispus under various cut-off filters to natural solar radiation on the North Sea island Helgoland, Germany. The laboratory-grown

  11. Antimutagenic action of mammalian placental extracts on mutations induced in Escherichia coli by UV radiation,. gamma. -rays and N-methyl-N'-nitro-N-nitrosoguanidine

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, H.; Kada, T. (National Inst. of Genetics, Mishima, Shizuoka (Japan). Dept. of Induced Mutation)

    1982-01-01

    Mammalian placental extracts prepared from human, monkey, dog, rat and mouse had strong antimutagenic activities for reverse mutations induced in Escherichia coli B/r WP2 trp/sup -/ by UV radiation, ..gamma..-rays and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG).

  12. DNA damage and photosynthetic performance in the Antarctic terrestrial alga Prasiola crispa ssp antarctica (Chlorophyta) under manipulated UV-B radiation

    NARCIS (Netherlands)

    Lud, D; Buma, AGJ; van de Poll, W; Moerdijk, TCW; Huiskes, AHL

    The effect of reduced, natural ambient, and enhanced UV-B radiation (UVBR) on photosynthesis and DNA damage in the Antarctic terrestrial alga Prasiola crispa ssp. antarctica (Kutzing) Knebel was investigated in two field experiments. Samples of P. crispa were collected underneath snow cover and

  13. DNA damage and photosynthetic performance in the Antarctic terrestrial alga Prasiola crispa ssp antarctica (Chlorophyta) under manipulated UV-B radiation

    NARCIS (Netherlands)

    Lud, D.; Buma, A.G.J.; van de Poll, W.H.; Moerdijk-Poortvliet, T.C.W.; Huiskes, A.H.L.

    2001-01-01

    The effect of reduced, natural ambient, and enhanced UV-B radiation (UVBR) on photosynthesis and DNA damage in the Antarctic terrestrial alga Prasiola crispa ssp. antarctica (Kutzing) Knebel was investigated in two field experiments. Samples of P. crispa were collected underneath snow cover and

  14. Effect of prestorage UV-A, -B, and -C radiation on fruit quality and anthocyanin of 'Duke' blueberries during cold storage.

    Science.gov (United States)

    Nguyen, Chau T T; Kim, Jeongyun; Yoo, Kil Sun; Lim, Sooyeon; Lee, Eun Jin

    2014-12-17

    Ultraviolet (UV)-A, -B, and -C were radiated to full-ripe blueberries (cv. 'Duke'), and their effects on fruit qualities and phytonutrients during subsequent cold storage were investigated. The blueberries were exposed to each UV light at 6 kJ/m(2) and then stored at 0 °C for 28 days. Weight loss and decay of the fruits after UV treatment were significantly decreased during the cold storage. The total phenolics and antioxidant activities of blueberries after UV-B and -C treatments were always higher than those of the control and UV-A treatment. Individual anthocyanins were markedly increased during the 3 h after the UV-B and -C treatments. The correlation matrix between total phenolics, anthocyanins, and antioxidant activity measured by the 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) assay indicated a significantly close correlation with the individual anthocyanin contents. It was confirmed that the prestorage treatments of UV-B and -C increased the storability and phytochemical accumulation of the full-ripe 'Duke' blueberries during cold storage.

  15. Effects of X-ray and extreme UV radiation on circumbinary planets

    Science.gov (United States)

    Sanz-Forcada, J.; Desidera, S.; Micela, G.

    2014-10-01

    Context. Several circumbinary planets have recently been discovered. The orbit of a planet around a binary stellar system poses several dynamic constraints. In addition to these constraints, the effects that radiation from the host stars may have on the planet atmospheres must be considered. We here evaluate these effects. Because of the configuration of a close binary system, these stars have a high rotation rate, even for old stars. The fast rotation of close, tidally locked binaries causes a permanent state of high stellar activity and copious XUV radiation. The accumulated effects are stronger than for normal exoplanets around single stars and cause a faster evaporation of their atmospheres. Aims: We evaluate the effects that stellar radiation has on the evaporation of exoplanets around binary systems and on the survival of these planets. Methods: We considered the X-ray and EUV spectral ranges (XUV, 1-912 Å) to account for the photons that are easily absorbed by a planet atmosphere that is mainly composed of hydrogen. A more complex atmospheric composition is expected to absorb this radiation more efficiently. We used direct X-ray observations to evaluate the energy in the X-rays range and coronal models to calculate the (nondetectable) EUV part of the spectrum. Results: We considered in this problem different configurations of stellar masses, and a resonance of 4:1 and 3:1. The simulations show that exoplanets orbiting close binary systems in a close orbit will suffer strong photoevaporation that may cause a total loss of atmosphere in a short time. We also applied our models to the best real example, Kepler-47 b, to estimate the current mass-loss rates in circumbinary planets and the accumulated effects over the time. Conclusions: A binary system of two solar-like stars will be highly efficient in evaporating the atmosphere of the planet (less than 6 Gyr in our case). These systems will be difficult to find, even if they are dynamically stable. Still

  16. Aplicação de radiação UV artificial e solar no tratamento fotocatalítico de efluentes de curtume Application of artificial and solar UV radiation in the photocatalytic treatment of a tannery effluent

    Directory of Open Access Journals (Sweden)

    Salomão de Andrade Pascoal

    2007-10-01

    Full Text Available Tannery effluents are very dangerous for the environment since they contain large amounts of dangerous and biorecalcitrant contaminants (organic matter and Cr(VI. This paper reports the efficiency of heterogeneous photocatalysis, based on the application of solar and artificial radiation, furnished by UV lamps, using TiO2 fixed on a flat plate, in the treatment of synthetic effluents. The results of COD and Cr(VI demonstrate that the use of solar radiation is the most efficient way to perform the photocatalytic treatment of these effluents since a minimum removal of 62 and 61% was observed for Cr(VI and organic matter, respectively.

  17. Comparison of ground-based measurements of solar UV radiation at four sites on the Tibetan Plateau.

    Science.gov (United States)

    Norsang, Gelsor; Chen, Yi-Chun; Pingcuo, Nima; Dahlback, Arne; Frette, Øyvind; Kjeldstad, Berit; Hamre, Børge; Stamnes, Knut; Stamnes, Jakob J

    2014-02-01

    We compare results for the UV index (UVI), the total ozone column (TOC), and the radiation modification factor (RMF, being 1 in the absence of clouds and aerosols) at four sites on the Tibetan Plateau. The results were obtained by analyzing ground measurements by multichannel moderate-bandwidth filter instruments for the period July 2008-September 2010, and radiative transfer modeling was used to aid the interpretation of the results. The highest UVI of 20.6 was measured in Tingri (28.7°N; 4335 m). For July, monthly mean UVI values were 14.5 and 12.9 in Tingri and Lhasa (29.7°N; 3683 m), respectively. Generally, the UVI levels in Tingri and Lhasa were higher than in Nagchu (31.5°N; 4510 m) and Linzhi (29.7°N; 2995 m), due to less cloud cover at the former two sites. In 2009, the annual mean UVI and RMF values were 6.8 and 0.7 for Linzhi, 8.8 and 0.92 for Lhasa, 10.5 and 0.92 for Tingri, and 6.7 and 0.7 for Nagchu. Radiative transfer simulations indicate that the latitude difference would correspond to an increase in the UVI of about 0.3 from Nagchu to Tingri; whereas, the altitude difference would correspond to a reduction of about 1.5%, implying that the observed difference is due to the difference in cloud cover. The annual mean TOC values were found to be 260-264 Dobson units (DU) in Lhasa, Linzhi, and Nagchu, and 252 DU in Tingri. TOC values in Lhasa were found to agree within 3% with those derived from Ozone Monitoring Instrument (OMI) measurements.

  18. Physiological responses of macroalga Gracilaria lemaneiformis (Rhodophyta) to UV-B radiation exposure

    Science.gov (United States)

    Zhu, Lin; Xiao, Hui; Wang, Ying; Jian, Xiaoyang; Zhang, Zhipeng; Zhang, Huanxin; Tang, Xuexi

    2015-03-01

    This paper aims to evaluate the effects of ultraviolet-B radiation (UVBR) on Gracilaria lemaneiformis, a commercial red macroalga and an important source of agar. To study the in-vitro effect of UVBR on G. lemaneiformis, this plant was cultivated and exposed to photosynthetically active radiation (PAR) at 40 μmol photons/(m2 ·s) and enhanced UVBR (0, 0.36, 0.72, 1.08, 1.44, and 1.80 kJ/(m2 ·d)) for 13 days. The samples were processed for histochemical analysis, and the growth rate, photosynthetic pigment contents, photosynthetic performance, reactive oxygen species levels, membrane permeability, malonyl dialdehyde contents and antioxidant capacity of G. lemaneiformis were investigated. After 13 days of exposure to PAR+UVBR, G. lemaneiformis showed photodamage and photoinhibition of photosynthetic pigments (chlorophyll a and phycoerythrin), leading to a decreased photosynthetic efficiency. Further, there was a corresponding decrease in the relative growth rates and depigmentation and partial necrosis of the apical segments were noted after exposure to PAR+UVBR. Additionally, UVBR induced excess production of superoxide radicals and hydrogen peroxide, eliciting a marked cellular membrane damage and antioxidative response.

  19. Defective-interfering particles of the human parvovirus adeno-associated virus. [uv radiation

    Energy Technology Data Exchange (ETDEWEB)

    Laughlin, C.A.; Myers, M.W.; Risin, D.L.; Carter, B.J.

    1979-04-15

    We have previously shown that adeno-associated virus (AAV) grown in KB cells with a helper adenovirus, produced several classes of particles defined by their buoyant density in CsCl. The predominant density classes were referred to as AAV(1.45), AAV(1.41), AAV (1.35), and AAV(1.32), respectively, where the density of the particle was written in the parentheses. The AAV(1.45) and AAV(1.41) particles which contained standard genomes were the only infectious AAV these infectious AAV particles exhibited autointerference. The ligh-density AAV(1.35) and (1.32) particles contained aberrant (deleted and/or snap-back) genomes. We report here experiments which show that the light-density AAV particles were noninfectious but interfered with the replication of AAV(1.41). The interference was intracellular and resulted in inhibition of synthesis of standard (14.5S) AAV genomes. In some cases there was also a concomitant increase in synthesis of aberrant, shorter AAV DNA. The inhibitory activity of the light-density particles was abolished by uv irradiation. These results show that the population of light AAV particles contained DI particles. The observed autointerference of AAV(1.45) or AAV(1.41) virus is postulated to be due to AAV DI particles. Replication of AAV DI genomes appeared to require the presence of replicating, standard AAV genomes. This is interpreted to mean that progeny strand replication of AAV requires an AAV-specified product, presumably the AAV capsid protein. In contrast to standard, infectious AAV, the AAV DI particles alone do not inhibit replication of the helper adenovirus.

  20. Impact of UV-A radiation on the performance of aphids and whiteflies and on the leaf chemistry of their host plants.

    Science.gov (United States)

    Dáder, Beatriz; Gwynn-Jones, Dylan; Moreno, Aránzazu; Winters, Ana; Fereres, Alberto

    2014-09-05

    Ultraviolet (UV) radiation directly regulates a multitude of herbivore life processes, in addition to indirectly affecting insect success via changes in plant chemistry and morphogenesis. Here we looked at plant and insect (aphid and whitefly) exposure to supplemental UV-A radiation in the glasshouse environment and investigated effects on insect population growth. Glasshouse grown peppers and eggplants were grown from seed inside cages covered by novel plastic filters, one transparent and the other opaque to UV-A radiation. At a 10-true leaf stage for peppers (53 days) and 4-true leaf stage for eggplants (34 days), plants were harvested for chemical analysis and infested by aphids and whiteflies, respectively. Clip-cages were used to introduce and monitor the insect fitness and populations of the pests studied. Insect pre-reproductive period, fecundity, fertility and intrinsic rate of natural increase were assessed. Crop growth was monitored weekly for 7 and 12 weeks throughout the crop cycle of peppers and eggplants, respectively. At the end of the insect fitness experiment, plants were harvested (68 days and 18-true leaf stage for peppers, and 104 days and 12-true leaf stage for eggplants) and leaves analysed for secondary metabolites, soluble carbohydrates, amino acids, total proteins and photosynthetic pigments. Our results demonstrate for the first time, that UV-A modulates plant chemistry with implications for insect pests. Both plant species responded directly to UV-A by producing shorter stems but this effect was only significant in pepper whilst UV-A did not affect the leaf area of either species. Importantly, in pepper, the UV-A treated plants contained higher contents of secondary metabolites, leaf soluble carbohydrates, free amino acids and total content of protein. Such changes in tissue chemistry may have indirectly promoted aphid performance. For eggplants, chlorophylls a and b, and carotenoid levels decreased with supplemental UV-A over the entire

  1. Effect of UV radiation on thermotolerance, ethanol tolerance and osmotolerance of Saccharomyces cerevisiae VS1 and VS3 strains.

    Science.gov (United States)

    Sridhar, M; Sree, N Kiran; Rao, L Venkateswar

    2002-07-01

    After a previous mass screening and enrichment programme for the isolation of thermotolerant yeasts, VS1, VS2, VS3 and VS4 strains isolated from soil samples, collected within the hot regions of Kothagudem Thermal Power Plant, AP, India, had a better thermotolerance, osmotolerance and ethanol tolerance than the other isolates. Among these isolates VS1 and VS3 were best performers. Efforts were made to further improve their osmotolerance, thermotolerance and ethanol tolerance by treating them with UV radiation. Mutants of VS1 and VS3 produced more biomass and ethanol than the parent strains at high temperature and glucose concentrations. The amount of biomass produced by VS1 and VS3 mutants was 0.25 and 0.20 g l(-1) more than the parent strains at 42 degrees C using 2% glucose. At high glucose concentrations VS1 and VS3 mutants produced biomass which was 0.70 and 0.30 g l(-1) at 30 degrees C and 0.10 and 0.20 g l(-1) at 40 degrees C more than the parent strains. The amount of ethanol produced by the mutants (VS1 and VS3) was 8.20 and 1.20 g l(-1) more than the parent strains at 42 degrees C using 150 g l(-1) glucose. More ethanol was produced by mutants (VS1 and VS3) than the parents at high glucose concentrations of 5.0 and 6.0 g l(-1) at 30 degrees C and 13.0 and 3.0 g l(-1) at 42 degrees C, respectively. These results indicated that UV mutagenesis can be used for improving thermotolerance, ethanol tolerance and osmotolerance in VS1 and VS3 yeast strains.

  2. Demonstration of bacteriocin activity in bovine and bison strains of Pasteurella multocida. [UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chengappa, M.M.; Carter, G.R.

    1977-08-01

    Of 33 strains of Pasteurella multocida examined, 14 showed bacteriocin activity and 17 were susceptible to bacteriocin. The activity was increased by about twofold if the cultures were induced with ultraviolet radiation; however, no increase in bacteriocin activity was observed if the potential producer strains were induced with mitomycin C. The bacteriocin activity of potential producer strains was increased if CaCl/sub 2/ was incorporated in the medium. The patterns of bacteriocin susceptibility indicate that these substances may ultimately contribute to a typing scheme for the species. An extra-chromosomal genetic element was not detected when a potential producer strain was not detected when a potential producer strain was tested by the dye-buoyant density gradient method. This fact suggests that the genetic material responsible for bacteriocin activity in P multocida is located on the host chromosome proper.

  3. Second Order Harmonics Suppression With Glass Filters for Synchrotron UV Radiation Calibration Measurement

    CERN Document Server

    Burattini, E; Gambicorti, L; Malvezzi, F; Marcelli, A; Monti, F; Pace, E

    2005-01-01

    This development is the latest result of the cooperation between the National Laboratories of Frascati and the Department of Astronomy and Space Science of the University of Florence to improve the capabilities of the existing DXR-2 beam line at the DAΦNE-LIGHT laboratories. This collaboration has assessed a new facility in order to characterize optics and sensors in a wide spectral range (ranging from VUV to IR). Previous measurements [1] have highlighted some limitations in the present setup, as higher signal levels due to the diffracted radiation of the grating in the second order have to be removed to allow an accurate detection. In this work a glass filter is used to remove such spurious signal present in the spectral region with λ > 360 nm. The characteristics of the filter and its application to the optical system used to measure the sensitivity of a diamond-based photoconductor have been discussed.

  4. DNA Base Damage by Reactive Oxygen Species, Oxidizing Agents, and UV Radiation

    Science.gov (United States)

    Cadet, Jean; Wagner, J. Richard

    2013-01-01

    Emphasis has been placed in this article dedicated to DNA damage on recent aspects of the formation and measurement of oxidatively generated damage in cellular DNA in order to provide a comprehensive and updated survey. This includes single pyrimidine and purine base lesions, intrastrand cross-links, purine 5′,8-cyclonucleosides, DNA–protein adducts and interstrand cross-links formed by the reactions of either the nucleobases or the 2-deoxyribose moiety with the hydroxyl radical, one-electron oxidants, singlet oxygen, and hypochlorous acid. In addition, recent information concerning the mechanisms of formation, individual measurement, and repair-rate assessment of bipyrimidine photoproducts in isolated cells and human skin upon exposure to UVB radiation, UVA photons, or solar simulated light is critically reviewed. PMID:23378590

  5. The role of UV radiation and vitamin D in the seasonality and outcomes of infectious disease.

    Science.gov (United States)

    Abhimanyu; Coussens, Anna K

    2017-03-16

    The seasonality of infectious disease outbreaks suggests that environmental conditions have a significant effect on disease risk. One of the major environmental factors that can affect this is solar radiation, primarily acting through ultraviolet radiation (UVR), and its subsequent control of vitamin D production. Here we show how UVR and vitamin D, which are modified by latitude and season, can affect host and pathogen fitness and relate them to the outcomes of bacterial, viral and vector-borne infections. We conducted a thorough comparison of the molecular and cellular mechanisms of action of UVR and vitamin D on pathogen fitness and host immunity and related these to the effects observed in animal models and clinical trials to understand their independent and complementary effects on infectious disease outcome. UVR and vitamin D share common pathways of innate immune activation primarily via antimicrobial peptide production, and adaptive immune suppression. Whilst UVR can induce vitamin D-independent effects in the skin, such as the generation of photoproducts activating interferon signaling, vitamin D has a larger systemic effect due to its autocrine and paracrine modulation of cellular responses in a range of tissues. However, the seasonal patterns in infectious disease prevalence are not solely driven by variation in UVR and vitamin D levels across latitudes. Vector-borne pathogens show a strong seasonality of infection correlated to climatic conditions favoring their replication. Conversely, pathogens, such as influenza A virus, Mycobacterium tuberculosis and human immunodeficiency virus type 1, have strong evidence to support their interaction with vitamin D. Thus, UVR has both vitamin D-dependent and independent effects on infectious diseases; these effects vary depending on the pathogen of interest and the effects can be complementary or antagonistic.

  6. Links between extreme UV-radiation, total ozone, surface albedo and cloudiness: An analysis of 30 years of data from Switzerland and Austria

    Science.gov (United States)

    Rieder, H. E.; Staehelin, J.; Weihs, P.; Vuilleumier, L.; Blumthaler, M.; Holawe, F.; Lindfors, A.; Maeder, J. A.; Simic, S.; Wagner, J. E.; Walker, D.; Ribatet, M.

    2009-04-01

    Since the discovery of anthropogenic ozone depletion in the early 1970s (e.g. Molina and Rowland, 1974; Farman et al., 1985) the interest in stratospheric ozone trends and solar UV-B increased within the scientific community and the general public because of the link between reduced total column ozone and increased UV-radiation doses. Stratospheric ozone (e.g. Koch et al., 2005) and erythemal UV-radiation (e.g. Rieder et al., 2008) in the northern mid-latitudes are characterized by strong temporal variability. Long-term measurements of UV-B radiation are rare and datasets are only available for few locations and most of these measurements do not provide spectral information on the UV part of the spectra. During strong efforts in the reconstruction of erythemal UV, datasets of past UV-radiation doses became available for several measurement sites all over the globe. For Switzerland and Austria reconstructed UV datasets are available for 3 measurement sites (Davos, Sonnblick and Vienna) (Lindfors and Vuilleumier, 2005; Rieder et al., 2008). The world's longest ozone time series dating back to 1926 is available from Arosa, Switzerland, and is discussed in detail by Staehelin et al. (1998a,b). Recently new tools from extreme value theory have been applied to the Arosa time series to describe extreme events in low and high total ozone (Rieder et al., 2009). In our study we address the question of how much of the extremes in UV-radiation can be attributed to extremes in total ozone, high surface albedo and cloudiness. An analysis of the frequency distributions of such extreme events for the last decades is presented to gain a better understanding of the links between extreme erythemal UV-radiation, total ozone, surface albedo and clouds. References: Farman, J. C., Gardiner, B. G., and Shanklin, J. D.: Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interaction, Nature, 315, 207-210, 1985. Koch, G., Wernli, H., Schwierz, C., Staehelin, J., and Peter, T

  7. Functional melanocortin 1 receptor Mc1r is not necessary for an inflammatory response to UV radiation in adult mouse skin.

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    Wolnicka-Glubisz, Agnieszka; De Fabo, Edward; Noonan, Frances

    2013-03-01

    The G-protein-coupled receptor, Mc1r, plays a major role in pigment production and has been reported to be important in the inflammatory response. We have investigated the effect of deficiency in Mc1r on UV-induced inflammation. Mice on the same genetic background were used - C57BL/6-c (albino), C57BL/6 (black), C57BL/6-Mc1r(e/e) deficient (yellow). FACS analysis of disaggregated skin showed a similar dose-dependent increase in Ly6G(+) and CD11b(+) cells in response to UV radiation in all groups. No differences in UV-induced edema or in DNA damage were detected between groups. The contact hypersensitivity response, neonatal immune tolerance and UV immunosuppression were all similar in C57BL/6 and C57BL/6-Mc1r(e/e) mice. We conclude that the absence of Mc1r does not impair the inflammatory response to UV radiation or the generation of immunosuppression. © 2013 John Wiley & Sons A/S.

  8. In situ measurement of VUV/UV radiation from low-pressure microwave-produced plasma in Ar/O2 gas mixtures

    Science.gov (United States)

    Iglesias, E. J.; Mitschker, F.; Fiebrandt, M.; Bibinov, N.; Awakowicz, P.

    2017-08-01

    Ultraviolet (UV) and vacuum ultraviolet (VUV) spectral irradiance is determined in low-pressure microwave-produced plasma, which is regularly used for polymer surface treatment. The re-emitted fluorescence in the UV/VIS spectral range from a sodium salicylate layer is measured. This fluorescence is related to VUV/UV radiation in different spectral bands based on cut-off filters. The background produced by direct emitted radiation in the fluorescence spectral region is quantified using a specific background filter, thus enabling the use of the whole fluorescence spectral range. A novel procedure is applied to determine the absolute value of the VUV/UV irradiance on a substrate. For that, an independent measurement of the absolute spectral emissivity of the plasma in the UV is performed. The measured irradiances on a substrate from a 25 Pa Ar/O2-produced plasma are in the range of 1015-1016 (photon~ s-1 cm-2). These values include the contribution from impurities present in the discharge.

  9. Adaptive melanin response of the soil fungus Aspergillus niger to UV radiation stress at "Evolution Canyon", Mount Carmel, Israel.

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    Natarajan Singaravelan

    Full Text Available BACKGROUND: Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to identify trait(s that evolve in direct response to selection, enhancing the organism's fitness. "Evolution Canyon" (EC in Israel mirrors a microcosmic evolutionary system across life and is ideal to study natural selection and local adaptation under sharply, microclimatically divergent environments. The south-facing, tropical, sunny and xeric "African" slope (AS receives 200%-800% higher solar radiation than the north-facing, temperate, shady and mesic "European" slope (ES, 200 meters apart. Thus, solar ultraviolet radiation (UVR is a major selection agent in EC influencing the organism-environment interaction. Melanin is a trait postulated to have evolved for UV-screening in microorganisms. Here we investigate the cause and effect relationship between differential UVR on the opposing slopes of EC and the conidial melanin concentration of the filamentous soil fungus Aspergillus niger. We test the working hypothesis that the AS strains exhibit higher melanin content than strains from the ES resulting in higher UV resistance. METHODOLOGY/PRINCIPAL FINDINGS: We measured conidial melanin concentration of 80 strains from the EC using a spectrophotometer. The results indicated that mean conidial melanin concentration of AS strains were threefold higher than ES strains and the former resisted UVA irradiation better than the latter. Comparisons of melanin in the conidia of A. niger strains from sunny and shady microniches on the predominantly sunny AS and predominantly shady ES indicated that shady conditions on the AS have no influence on the selection on melanin

  10. Aerosol radiative effect in UV, VIS, NIR, and SW spectra under haze and high-humidity urban conditions

    Science.gov (United States)

    Zhang, Ming; Ma, Yingying; Gong, Wei; Wang, Lunche; Xia, Xiangao; Che, Huizheng; Hu, Bo; Liu, Boming

    2017-10-01

    Aerosol properties derived from sun-photometric observations at Wuhan during a haze period were analyzed and used as input in a radiative transfer model to calculate the aerosol radiative effect (ARE) in ultraviolet (UV), visible (VIS), near-infrared (NIR), and shortwave (SW) spectra. The results showed that the aerosol optical depth (AOD) at 440 nm increased from 0.32 under clear-air conditions to 0.85 during common haze and 1.39 during severe haze. An unusual inverse relationship was found between the Ångström exponent (AE) and AOD during the haze period at Wuhan. Under high-humidity conditions, the fine-mode median radius of aerosols increased from 0.113 μm to approximately 0.2-0.5 μm as a result of hygroscopic growth, which led to increases in the AOD and decreases in the AE simultaneously. These changes were responsible for the inverse relationship between AE and AOD at Wuhan. The surface ARE in the UV (AREUV), VIS (AREVIS), NIR (ARENIR), and SW (ARESW) spectra changed from -4.46, -25.37, -12.15, and -41.99 W/m2 under clear-air conditions to -9.48, -53.96, -29.81, and -93.25 W/m2 during common hazy days and -12.89, -80.16, -55.17, and -148.22 W/m2 during severe hazy days, respectively, and the percentages of AREUV, AREVIS, and ARENIR in ARESW changed from 11%, 61%, and 28%-9%, 54%, and 37%, respectively. Meanwhile, the ARE efficiencies (REE) in SW varied from -206.5 W/m2 under clear-air conditions to -152.94 W/m2 during the common haze period and -131.47 W/m2 during the severe haze period. The smallest decreasing rate of the REE in NIR was associated with the increase of ARENIR. The weakened REE values were related to the strong forward scattering and weak backward scattering of fine aerosol particles with increasing size resulting from hygroscopic growth, while the variation of the single scattering albedo showed less impact. Source region analysis by back trajectories and the concentration weighted trajectory (CWT) method showed that black carbon came

  11. Alterations in the antibacterial potential of Synechococcus spp. PCC7942 under the influence of UV-B radiations on skin pathogens

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    Nida Fatima

    2017-11-01

    Full Text Available Marine organisms are seen as a source of novel drugs and the discovery of new pharmaceutical is increasingly in demand. Cyanobacteria are regarded as a potential target for this as antibacterial, antiviral, antifungal, algicide and cytotoxic activities have been reported in these organisms. They have been identified as a new and rich source of bioactive compounds belonging to diversified groups. Radiation in the UV-B range interferes with various metabolic reactions by generating free radicals and active oxygen species. These deleterious compounds are inactivated by antioxidants. Among them are the carotenoids and phycocyanin which protect against photodynamic action in different ways. Stress plays an important role in the production of bioactive metabolites from organisms. Synechococcus spp. PCC7942 was studied for antibacterial activity against various pathogenic bacteria resistant to a number of available antibiotics after being exposed to UV-B radiation. The antibacterial activity of Synechococcus spp. PCC7942 was studied on five potent skin pathogens. The highest antibacterial activity was seen the methanol extracts of 24 h UV-B exposed cultures of Synechococcus spp. PCC7942. It can be concluded that there was moderate antibacterial activity. Results showed stress, solvent and dose-dependent activity. This antibacterial activity might be due to the enhanced synthesis of carotenoids and phycocyanin under UV-B stress. The purpose of the present study was to relate the inhibitory effects of the cyanobacterial compounds specifically on skin pathogens with exposure to UV-B radiation as UV protecting compounds are already reported in these organisms.

  12. Development of a new in vitro method to evaluate the photoprotective sunscreen activity of plant extracts against high UV-B radiation.

    Science.gov (United States)

    Hupel, Mélanie; Poupart, Nathalie; Gall, Erwan Ar

    2011-10-30

    Sunscreen efficiency of biomolecules against UV-B radiation was generally determined in vitro by cosmetic methods which are not well-adapted for routine ecophysiological and bio-guidance studies in plant research laboratories. In this article, we propose a new in vitro method to evaluate the sunscreen photoprotective activity of plant extracts against high UV-B radiation. Because photosynthetic pigments are one of the first targets of UV-B radiation in plants, the experimental design is based on the ability of the tested substances to limit the degradation of sodium magnesium chlorophyllin (SMC), a derivative compound of natural chlorophyll. SMC photodegradation comparatively to natural chlorophyll and related to temperature, concentration and sample solvent were analyzed in order to optimize the e