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Sample records for agents uv radiation

  1. Investigating the stability of gadolinium based contrast agents towards UV radiation.

    Science.gov (United States)

    Birka, Marvin; Roscher, Jörg; Holtkamp, Michael; Sperling, Michael; Karst, Uwe

    2016-03-15

    Since the 1980s, the broad application of gadolinium(Gd)-based contrast agents for magnetic resonance imaging (MRI) has led to significantly increased concentrations of Gd in the aqueous environment. Little is known about the stability of these highly polar xenobiotics under environmental conditions, in wastewater and in drinking water treatment. Therefore, the stability of frequently applied Gd-based MRI contrast agents towards UV radiation was investigated. The hyphenation of hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICP-MS) and of HILIC with electrospray ionization mass spectrometry (ESI-MS) provided quantitative elemental information as well as structural information. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A showed a high stability in irradiation experiments applying a wavelength range from 220 nm to 500 nm. Nevertheless, the degradation of Gd-BOPTA as well as the formation of Gd-containing transformation products was observed by means of HILIC-ICP-MS. Matrix-dependent irradiation experiments showed a degradation of Gd-BOPTA down to 3% of the initial amount in purified water after 300 min, whereas the degradation was slowed down in drinking water and surface water. Furthermore, it was observed that the sum of species continuously decreased with proceeding irradiation in all matrices. After irradiation in purified water for 300 min only 16% of the sum of species was left. This indicates a release of Gd(III) ions from the complex in course of irradiation. HILIC-ESI-MS measurements revealed that the transformation products mostly resulted from O-dealkylation and N-dealkylation reactions. In good correlation with retention times, the majority of transformation products were found to be more polar than Gd-BOPTA itself. Based on accurate masses, sum formulas were obtained and structures could be proposed. PMID:26802476

  2. Mutational interactions between near-UV radiation and DNA damaging agents in Escherichia coli: the role of near-UV-induced modifications in growth and macromolecular synthesis

    International Nuclear Information System (INIS)

    The mutational interactions between near-ultraviolet (334 nm, 365 nm) radiation and DNA damaging agents (far-UV (254 nm) and ethyl-methanesulphonate (EMS)) were studied in strains of Escherichia coli B/r trp thy with different susceptibilities to near-UV-induced growth delay (wild-type, rel and sr). Far-UV induced reversion to tryptophan independence is reduced while forward mutation to streptomycin is enhanced by prior exposure of the rel+ srd+ strains to near-UV radiation. The observed interactions are reduced (rel) or absent (srd) in the two mutant strains as are the corresponding growth and macromolecular synthesis delays normally observed after near-UV treatment. Quantitatively, the degree of interaction induced by near-UV pre-treatment correlates closely with the degree of protein synthesis inhibition. A mechanism is proposed for the contrasting interactions at the two genetic loci based on the different pathways by which pre-mutagenic lesions may be processed. The primary chromophore for the mutational interactions would appear to be 4-thiouracil-containing transfer RNA. (author)

  3. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

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

  4. Pretreatment with UV light renders the chromatin in human fibroblasts more susceptible to the DNA-damaging agents bleomycin, gamma radiation and 8-methoxypsoralen

    International Nuclear Information System (INIS)

    Confluent human fibroblast cultures were pretreated with either 254 nm UV light (UV) or methyl methanesulphonate (MMS), incubated at 370C and subsequently challenged on ice with bleomycin (BLM), gamma-radiation or 8-methoxy-psoralen (MOP). The resulting number of challenge-induced DNA damages (measured as DNA strand breaks or cross-links) were compared with the numbers induced in similarly challenged but non-pretreated control cells. It was found that the timing of the subsequent challenge of cells pretreated with UV did significantly affect the amount of induced DNA damage. When the challenging agents were administered after a 10-20 min incubation period following UV pretreatment, the amount of induced DNA damage was increased 50% over control cells. In contrast, the timing of the subsequent challenge of cells pretreated with MMS has no influence on the level of challenge-induced damage. It is hypothesized that UV-irradiated chromatin undergoes a time-dependent decondensation that renders it more susceptible to the induction of strand breaks and cross-links by BLM, gamma-radiation and MOP. A possible role for chromatin decondensation in UV-induced excision repair is discussed. (author)

  5. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... 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 Written by: David ...

  6. Is UV-A radiation a cause of malignant melanoma?

    International Nuclear Information System (INIS)

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs

  7. Characterization of UV radiation sensitive frog cell lines

    International Nuclear Information System (INIS)

    Twenty-one subclones of nine frog cell isolates were tested for sensitivity to a panel of DNA damaging agents. Two clones were identified which had a greater than wild type level of sensitivity to UV radiation but had a wild type level of sensitivity to the other agents. These clones were the haploid RRP602-7 and the diploid RRP802-1. RRP802-1 was found to be unstable with respect to UV sensitivity. The line was cloned in order to isolate stable sensitive and wild type derivatives. RRP802-1-16, a UV sensitive clone and RRP802-1-13, a clone with a wild type level of sensitivity to UV radiation, were isolated. The UV radiation sensitivity of RRP602-7, RRP802-1 and RRP802-1-16 did not correlate with cell size, cell shape, cell cycle distribution or ploidy. The cell cycle distribution after UV irradiation, the rate of DNA synthesis after UV-irradiation, the DNA polymerase α activity and the sister chromatid exchange frequency were all measured in RRP602-7, RRP802-1 and RRP802-1-16 in order to examine the DNA repair capacity. The presence of DNA repair pathways was examined directly in RRP602-7, RRP802-1 and RRP802-1-16. All were found to be proficient in photo-reactivation repair and postreplication repair of UV elicited DNA damage

  8. Modulation of immune function by UV radiation

    International Nuclear Information System (INIS)

    In addition to its carcinogenic activity, ultraviolet (UV) radiation is capable of modifying certain immunologic reactions. Immunologic alterations induced in mice by UV radiation include both local and distant effects. Local alterations result from a direct effect of UV radiation on an immune reaction that takes place at the site of irradiation. Distant alterations are those in which exposure of skin to UV radiation at one site modifies an immune reaction occurring at a distant, unexposed site. Based on recent studies, the authors propose that there may be two types of distant alterations. One is nonspecific, may be due to accumulation of leukocytes at the site of UV-induced inflammation, and is exemplified by the suppression of delayed hypersensitivity and local graft-versus-host (GVH) reactions. The second may result from DNA damage, may involve a soluble mediator, and is manifested by the systemic suppression of contact hypersensitivity and the formation of antigen-specific suppressor T lymphocytes. These immunologic effects of exposure to UV radiation may be important in the pathogenesis of skin cancer and other cutaneous diseases

  9. UV radiation impairs the body's defence mechanism

    International Nuclear Information System (INIS)

    Ultraviolet (UV) radiation is usually divided into three wavelength ranges, which differ considerably from each other with respect to their effect on human health. UV-B radiation, in particular, weakens the body's resistance against cancer cells and thus increases cancer risk. Although virtually all UV-B radiation stops at the surface layer of skin, the whole body suffers from its adverse effects. UV radiation affects the body's defence mechanism relatively quickly. A reduction in the body's capacity to defend itself against alien substances can already be detected within a couple of days after the body has been exposed to a small amount of UV radiation. The risk of cancer increases slowly over the years. The skin cancers that are treated in hospitals today have their origin in the ways of life pursued in the 1960's and 70's. Factors affecting the amounts of UV doses received by Finns include trips to the South, solarium treatments and, to some extent, thinning of the ozone layer. (orig.) (4 figs.)

  10. Appraisal of alternative skin model for the study of epidermal restoration following exposure to various environmental stress agents: ionising radiation and UV B

    International Nuclear Information System (INIS)

    Human skin is a major target tissue for ionising radiation (IR) and UV B. We developed a skin explant model and used 2 types of keratinocytes to study survival and oxidative stress induced by these radiations. We examined oxidative damages by measuring R.O.S. produced and cellular anti-oxidant defenses induced. We observed into skin exposed to IR a modulation of genes expression implied in the control of oxidative stress, confirmed by the decrease of catalase, glutathione peroxidase and superoxide dismutase enzymatic activities. The imbalance observed between anti- and pro-apoptotic genes expression shows that keratinocytes apoptosis may be partly dependent on radio-induced R.O.S. production. We showed the difference of radiosensitivity between N.H.E.K. and Ha Ca.T., which may be linked to their differential oxidative responses. In addition, during re-epithelialising, we demonstrated that activated N.H.E.K. after IR express keratin 6, release pro-inflammatory cytokines and proliferate, without modification of their differentiation. Treatment of N.H.E.K. with geranyl geranylacetone (G.G.A.) has a beneficial effect on their radio-induced activation by increasing IL-1 release, their migration in scrapped area and their survival. G.G.A. has an anti apoptotic ability (induction of Hsp70- caspase-3 pathway) and migratory properties (P38/RhoA activation) on N.H.E.K., but after IR, only caspase-3 pathway is induced. This work thus contributes to the understanding of cutaneous damages after IR and G.G.A. mechanism of action which accelerates re-epithelialising. (author)

  11. Is UV-A radiation a cause of malignant melanoma. Er UV-A aarsak til malignt melanom

    Energy Technology Data Exchange (ETDEWEB)

    Moan, J. (Det Norske Radiumhospital, Oslo (Norway))

    1994-03-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs.

  12. Occupational UV exposure of environmental agents in Valencia, Spain

    OpenAIRE

    Serrano Jareño, María Antonia; Cañada, Javier; Moreno Esteve, Juan Carlos; Gurrea Ysasi, Gonzalo

    2014-01-01

    The aim of this paper is to measure UV exposure of environmental agents in their occupational schedules in summer in Valencia province (Spain) using VioSpor personal dosimeters attached to several parts of their bodies. Due to its geographical situation, Valencia receives large UVR doses throughout the year, and the work of environmental agents is directly related to the protection, care, and custody of natural, often in mountainous areas. Comparison with the occupational UV exposure limit sh...

  13. UV-type damage associated with ionizing radiation: a review

    International Nuclear Information System (INIS)

    The induction of UV-type damage by ionizing radiation in repair deficient strains of E. coli is reviewed. Both photoreactivable and non-photoreactivable types of damage can be observed. The induction of UV-type damage is largely independent of the presence of free-radical reactive agents (e.g. oxygen and thiols), but is dependent upon the energy of the photon-or electron-beam used, the radiation geometry and the optical absorbance of the extracellular medium. On the basis of calculations and experimental evidence, it is clear that one mechanism whereby such damage arises is through the generation of Cerenkov emission. However, small yields of UV-type damage can be produced using X-rays whose energy is below the threshold for production of Cerenkov emission. In this instance, the damage induction mechanism is thought to involve a direct excitation process. (author)

  14. Determination of the need for solar UV radiation protection

    OpenAIRE

    Letić Milorad

    2010-01-01

    Introduction. 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. Objective. The aim of the study is to establish a simple and co...

  15. Evaluation of damage to DNA induced by UV-C radiation and chemical agents using electrochemical biosensor based on low molecular weight DNA and screen-printed carbon electrode

    International Nuclear Information System (INIS)

    Highlights: ► Evaluation of damage to DNA induced by UV-C radiation and chemical agents. ► Utilization of an electrochemical DNA biosensor based on low molecular weight DNA. ► Utilization of screen-printed carbon electrode as an electrical transducer. ► Complex detection of double-stranded DNA damage. - Abstract: There is great interest and need to detect and evaluate damage to DNA by environmental factors. In the present paper, simple electrochemical DNA biosensors composed of commercially available screen-printed carbon electrode (SPCE) and low molecular weight double-stranded DNA (dsDNA) recognition layer are reported and applied to the detection of damage to DNA by UV-C radiation and reactive oxygen species produced by the Fenton type reaction in model as well as mineral water samples with additives. Complex DNA biosensor response is based on square-wave voltammetric intrinsic signal of the guanine moiety as well as that of the intercalative indicator thioridazine, cyclic voltammetric response of the [Fe(CN)6]3−/4− indicator in solution and on electrochemical impedance spectroscopy when the measurements can be performed in the same solution. For the last two types of measurements, the biosensor was also used with an interface between the SPCE and DNA formed by a composite of carboxylated single-walled carbon nanotubes and chitosan to enhance the transducer conductivity. Individual electrochemical/electrical signals depend on the time of biosensor incubation in a cleavage medium and their profiles characterize process of deep DNA degradation.

  16. Novel Radiation Sources in Vacuum UV and Near UV

    Science.gov (United States)

    Peng, Sheng; Ametepe, Joseph; Manos, Dennis

    2004-05-01

    Ultraviolet (UV) light induced or enhanced chemical reactions have many advanced applications. This causes excimer lamps which deliver high power, large area UV radiations in demand. There have been extensive studies on rare gas or mixtures of rare gas halogen in different excimer lamps. But experimental data for high pressure KrI (iodine in krypton) spectra are scarce partially because the transitions B->X (191nm) and B->A (225nm) are usually very weak. We designed a new prototype of rf lamp for this study. This lamp has its electrodes outside the plasma for longer lamp lifetime. It is capable of studying most rf excited gas discharge and efficient enough for weak emissions like KrI. Detailed features of KrI spectrum from 160nm to 360nm were obtained. The wavelength and intensity variation of with pressure was modeled using a set of coupled kinetic equations. Molecular orbits of KrI were calculated in Gaussian 03. A semi-classical approach was used to study the line shape of the broad band emission and an explicit expression was obtain for KrI.

  17. Skin cancer and solar UV radiation.

    Science.gov (United States)

    de Gruijl, F R

    1999-12-01

    Ultraviolet (UV) radiation in sunlight is the most prominent and ubiquitous physical carcinogen in our natural environment. It is highly genotoxic but does not penetrate the body any deeper than the skin. Like all organisms regularly exposed to sunlight, the human skin is extremely well adapted to continuous UV stress. Well-pigmented skin is clearly better protected than white Caucasian skin. The sun-seeking habits of white Caucasians in developed countries are likely to have contributed strongly to the increase in skin cancer observed over the last century. Skin cancer is by far the most common type of cancer in the U.S.A. and Australia, which appears to be the result of an 'unnatural displacement' of people with sun-sensitive skin to sub-tropical regions. Although campaigns have been successful in informing people about the risks of sun exposure, general attitudes and behaviour do not yet appear to have changed to the extent that trends in skin cancer morbidity and the corresponding burden on public healthcare will be reversed. The relationship between skin cancer and regular sun exposure was suspected by physicians in the late 19th century, and subsequently substantiated in animal experiments in the early part of the 20th century. UV radiation was found to be highly genotoxic, and DNA repair proved to be crucial in fending off detrimental effects such as mutagenesis and cell death. In fact, around 1940 it was shown that the wavelength dependence of mutagenicity paralleled the UV absorption by DNA. In the 1970s research on UV carcinogenesis received a new impetus from the arising concern about a possible future depletion of the stratospheric ozone layer: the resulting increases in ambient UV loads were expected to raise skin cancer incidences. Epidemiological studies in the last decades of the 20th century have greatly refined our knowledge on the aetiology of skin cancers. Analyses of gene mutations in skin carcinomas have identified UV radiation as the cause

  18. UV radiation and its effects. Proceedings

    International Nuclear Information System (INIS)

    The National Science Strategy Committee for Climate Change was established in 1991 by the New Zealand Minister of Research, Science and Technology. It advises government through the Minister on research priorities and on levels of expenditure appropriate in various topics relating to climate change. An additional role is to promote coordination between research groups and the user communities to ensure an appropriate range of research strategies. To assist with implementing the latter aspects the NSS Committee will organise workshops on specific aspects of atmosphere and climate change, with a broad spectrum of participants. The first of these was the Workshop on UV Radiation and its Effects held in Christchurch on 20-21 May 1993. The workshop had 40 participants, including representatives from specialist science groups, medicine, veterinary science, farming, forestry and environmental groups. This publication will update the interested reader, whether scientist or lay-person, on the current state of knowledge on changing UV radiation levels and potential problems. As the summaries of papers show, research on ozone levels and on UV radiation and its effects is particularly appropriate for New Zealand scientists with their access to sites covering a wide range of latitudes from Antarctica to the Pacific Islands. New Zealand is part of an important international monitoring network, measuring local stratospheric ozone levels and related surface UV radiation levels. There are concerns about increasing UVB levels and the consequent effects on human health, plant and tree growth, and phytoplankton growth in the oceans. Priorities for further work on these areas are included in the summary of the workshop. (author). 13 figs.; 5 tabs

  19. Comparison of the dose-effect relationship for UV radiation and ionizing radiation

    International Nuclear Information System (INIS)

    Ionizing radiation and ultraviolet radiation (UV) are both physical agents with mutagenic and carcinogenic properties. However, there are some basic differences in the fundamental mechanism of their interaction with biological material that may have consequences for risk assessment. In this paper the dose-effect relationships for gamma radiation and UV at cellular level will be used to demonstrate the different radio-biological effectiveness of both agents. The results will be discussed in the framework of a biophysical model, based on the assumption that DNA doublestranded lesions are crucial for the cytotoxic action. After exposure to ionizing radiation, the lesions are fixed immediately following irradiation, but after UV exposure the lethal lesions are recognized only in the next DNA synthesis phase. The combination of this concept with the mechanism of lesion induction and the possibility of repair, leads to different dose and time relationships for the radiation effects of both agents. The possible consequences for risk assessment at low levels will be discussed. (author). 9 refs.; 5 figs

  20. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND, B.M.

    2001-07-26

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

  1. Modelling of ground-level UV radiation

    Science.gov (United States)

    Koepke, P.; Schwander, H.; Thomalla, E.

    1996-06-01

    A number of modifications were made on the STAR radiation transmission model for greater ease of use while keeping its fault liability low. The improvements concern the entire aerosol description function of the model, the option of radiation calculation for different receiver geometries, the option of switching off temperature-dependent ozone absorption, and simplications of the STAR menu. The assets of using STAR are documented in the studies on the accuracy of the radiation transmission model. One of these studies gives a detailed comparison of the present model with a simple radiation model which reveals the limitations of approximation models. The other examines the error margin of radiation transmission models as a function of the input parameters available. It was found here that errors can be expected to range between 5 and 15% depending on the quality of the input data sets. A comparative study on the values obtained by measurement and through the model proved this judgement correct, the relative errors lying within the predicted range. Attached to this final report is a comprehensive sensitivity study which quantifies the action of various atmospheric parameters relevant to UV radiation, thus contributing to an elucidation of the process.

  2. Molecular responses of plants to solar UV-B and UV-A radiation

    OpenAIRE

    Morales Suárez, Luis Orlando

    2014-01-01

    Plant responses to solar ultraviolet radiation (UV, 280-400 nm) were assessed at different molecular levels using Betula pendula Roth (silver birch) and Arabidopsis thaliana (Arabidopsis) as model species in outdoor experiments to assess the possibly interacting roles of the UV-B and UV-A wavebands in acclimation to sunlight. Solar UV-B (280-315 nm) and UV-A (315-400 nm) irradiance was attenuated with plastic films. Both solar UV-B and UV-A promoted the acclimation of silver birch and Arabido...

  3. Formation of Primordial Galaxies under UV background Radiation

    CERN Document Server

    Susa, H; Susa, Hajime; Umemura, Masayuki

    2000-01-01

    The pancake collapse of pregalactic clouds under UV background radiation is explored with a one-dimensional sheet model. Here, attention is concentrated on elucidating the basic physics on the thermal evolution of pregalactic clouds exposed to diffuse UV radiation. So, we treat accurately the radiation transfer for the ionizing photons, with solving chemical reactions regarding hydrogen molecules as well as atoms. The self-shielding against UV radiation by H$_2$ Lyman-Werner bands, which regulates the photo-dissociation of hydrogen molecules, is also taken into account. As a result, it is found that when the UV background radiation is at a level of $10^{-22} (\

  4. Solar UV radiation reduces the barrier function of human skin

    OpenAIRE

    Biniek, Krysta; Levi, Kemal; Dauskardt, Reinhold H.

    2012-01-01

    The ubiquitous presence of solar UV radiation in human life is essential for vitamin D production but also leads to skin photoaging, damage, and malignancies. Photoaging and skin cancer have been extensively studied, but the effects of UV on the critical mechanical barrier function of the outermost layer of the epidermis, the stratum corneum (SC), are not understood. The SC is the first line of defense against environmental exposures like solar UV radiation, and its effects on UV targets with...

  5. Spatial interpolation of biologically effective UV radiation over Poland

    Science.gov (United States)

    Walawender, J.; Ustrnul, Z.

    2010-09-01

    The ultraviolet(UV) radiation plays an important role in the Earth-Atmosphere System. It has a positive influence on both human health and natural environment but it may also be very harmful if UV exposure exceeds "safe" limits. For that reason knowledge about spatial distribution of biologically effective UV doses seems to be crucial in minimization or complete elimination of the negative UV effects. The main purpose of this study is to find the most appropriate interpolation method in order to create reliable maps of the biologically effective UV radiation over Poland. As the broadband UV measurement network in Poland is very sparse, erythemaly weighted UV radiation data reconstructed from homogeneous global solar radiation records were used. UV reconstruction model was developed in Centre of Aerology (Institute of Meteorology and Water Management) within COST Action 726 - ‘Long term changes and climatology of UV radiation over Europe'. The model made it possible to reconstruct daily erythemal UV doses for 21 solar radiation measurement stations in the period 1985 - 2008. Mapping methodology included the following processing steps: exploratory spatial data analysis, verification of additional variables, selection and parameterization of interpolation model, accuracy assessment and cartographic visualization. Several different stochastic and deterministic interpolation methods along with various empirical semivariogram models were tested. Multiple regression analysis was performed in order to examine statistical relationship between UV radiation and additional environmental variables such as: elevation, latitude, stratospheric ozone content and cloud cover. The data were integrated, processed and visualized within GIS environment.

  6. UV radiation dependent flavonoid accumulation of Cistus laurifolius L

    International Nuclear Information System (INIS)

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

  7. 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

    moderate and high doses of UV and ionizing radiation induce cell death by necrosis and generate systemic inflammatory response syndrome (SIRS), toxic multiple organ injury (TMOI), toxic multiple organ dysfunction syndromes (TMODS),and finally, toxic multiple organ failure (TMOF). [D.Popov et al.2012, Fliedner T.et al. 2005, T. Azizova et al. 2004] UV-B is a complete carcinogen that is absorbed by DNA and directly damages DNA. DNA damage induced by UV-B irradiation typically includes the formation of cyclobutane pyrimidine dimmers (CPD) and 6-4 photoproducts (6-4P)[IARC, Working Group Reports, M.Saraiya et al. 2004]. The pre-vaccinated animals seem to have a blunted injury response relative to the unvaccinated animals, presumably by reduction in the inflammatory response and secondary injury effects. The mechanism of action of the antiradiation vaccine, needs further evaluation. Conclusion: A UV antiradiation vaccine appears to demonstrate efficacy as a prophylactic agent for acute solar burns and toxicity. An antiradiation UV vaccine could be used in conjunction with adjunctive measures, e.g. antioxidants and UV barriers to reduce UV radiation toxicity. The authors of this experiments would like to propose further development work of the antiradiation UV vaccine to enhance the armamentarium for prophylaxis and prevention of the various forms skin cancer.

  8. 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.

  9. Exposure to UV radiation and human health

    Science.gov (United States)

    Kimlin, Michael G.

    2005-08-01

    This paper will overview the significant issues facing researchers in relating the impact of exposure to sunlight and human health. Exposure to solar ultraviolet radiation is the major causative factor in most sun-related skin and eye disorders, however, very little is known quantitatively about human UV exposures. Interestingly, human exposure to sunlight also has a nutritional impact, namely the development of pre-Vitamin D, which is an important nutrient in bone health. New research suggest that low vitamin D status may be a causative factor in the development of selective types of cancer and autoimminue diseases, as well as a contributing factor in bone health. The 'health duality' aspect of sunlight exposure is an interesting and controversial topic that is a research focus of Kimlin's research group.

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

    International Nuclear Information System (INIS)

    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 35S-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)

  11. 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).

  12. Sensitivity to DNA-damaging agents and mutation induction by UV light in UV-sensitive CHO cells

    International Nuclear Information System (INIS)

    Three UV-sensitive (UVs) mutants isolated from a CHO cell line were analyzed for survival after exposure to H2O2, EMS, MMC, CCNU, X-rays and for mutation induction after UV-irradiation. The UVs mutants showed normal sensitivities to EMS and H2O2, whereas they were hypersensitive to the bifunctional alkylating agents MMC and CCNU and to hypoxic X-irradiation. Compared to parental cells, one of the UV-sensitive clones showed approximately 3- and 7-fold enhancement in the mutagenic response per unit UV dose for 6-thioguanine and ouabain resistance, respectively. (Auth.)

  13. UV-generated free radicals (FR) in skin: Their prevention by sunscreens and their induction by self-tanning agents

    Science.gov (United States)

    Jung, K.; Seifert, M.; Herrling, Th.; Fuchs, J.

    2008-05-01

    In the past few years, the cellular effects of ultraviolet (UV) irradiation induced in skin have become increasingly recognized. Indeed, it is now well known that UV irradiation induces structural and cellular changes in all the compartments of skin tissue. The generation of reactive oxygen species (ROS) is the first and immediate consequence of UV exposure and therefore the quantitative determination of free radical reactions in the skin during UV radiation is of primary importance for the understanding of dermatological photodamage. The RSF method (radical sun protection factor) herein presented, based on electron spin resonance spectroscopy (ESR), enables the measurement of free radical reactions in skin biopsies directly during UV radiation. The amount of free radicals varies with UV doses and can be standardized by varying UV irradiance or exposure time. The RSF method allows the determination of the protective effect of UV filters and sunscreens as well as the radical induction capacity of self-tanning agents as dihydroxyacetone (DHA). The reaction of the reducing sugars used in self-tanning products and amino acids in the skin layer (Maillard reaction) leads to the formation of Amadori products that generate free radicals during UV irradiation. Using the RSF method three different self-tanning agents were analyzed and it was found, that in DHA-treated skin more than 180% additional radicals were generated during sun exposure with respect to untreated skin. For this reason the exposure duration in the sun must be shortened when self-tanners are used and photoaging processes are accelerated.

  14. Recent studies on UV radiation in Brazil

    Science.gov (United States)

    Correa, M. P.; Ceballos, J. C.; Moregula, A.; Okuno, E.; Fausto, A.; Mol, A.; Santos, J. C.

    2009-04-01

    This presentation shows a summary of UV index measurements performed in the last years in Southeastern (SE) and Northeastern (NE) Brazilian regions. Brazil has an area of 8.5 million km2 distributed between latitudes 5˚ N and 35˚ S and longitudes 5˚ W and 75˚ W. SE is the most important economic pole of South America and the NE coast is an important tourist region. This large area has a great diversity of climatic, atmospheric and geographical conditions in addition to very diverse social and cultural habits. Non-melanoma skin cancer (NMSC) is an epidemiological health problem with more than 120,000 new cases each year. The most of these cases are found in the South and Southeast regions, with about 70 new NMSC per 100,000 inhabitants. Solar Light UV501 biometers are installed in the SE cities of São Paulo (23.6˚ S, 46.7˚ W, 865 m ASL), Itajubá/Minas Gerais (22.4˚ S; 45.5˚ W, 846 m ASL) and the NE city of Ilhéus/Bahia (14.8˚ S; 39.3˚ W; 54 m ASL). First measurements began in 2005 in São Paulo city, while Itajubá and Ilhéus have regular measurements from the beginning of 2008. Other studies related to the UV radiation modeling and interactions with atmosphere components, as ozone, aerosols and clouds, have also been performed. For example: a) UVI modelling calculations performed by a multiple-scattering spectral models; b) studies on the aerosol radiative properties based on satellite (MODIS/Terra-Aqua) and ground-based (Aeronet) observation; c) ozone content variability from satellite (OMI/Aura) and ground-based (Microtops ozonometer) measurements; d) behavioral profile of the population, as regarding habits of solar exposure and sun protection measures. Results show that more than 75% of the measurements conducted in the summer (outside noon) can be classified as upper than high UVI according to World Health Organization (WHO) recommended categories: Low (UVI < 2), Medium (3 ? UVI < 6), High (6 ? UVI < 8), Very High (8 ? UVI

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

    Science.gov (United States)

    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.

  16. The impact of solar UV radiation on the early biosphere

    Science.gov (United States)

    Horneck, G.

    2007-08-01

    Stratospheric ozone, photochemically produced from atmospheric oxygen, is a protective filter of the Earth's atmosphere by absorbing most of the biologically harmful UV radiation of our sun in the UV-C (190-280 nm) and short wavelength-region of the UV-B (280-315 nm). Numerous lines of isotopic and geologic evidence suggest that the Archean atmosphere was essentially anoxic. As a result the column abundance of ozone would have been insufficient to affect the surface UV radiation environment. Thus, as well as UV-B radiation, UV-C radiation would have penetrated to the Earth's surface with its associated biological consequences. The history of this ultraviolet stress for the early Earth has been determined from theoretical data and data obtained in Earth orbit on the inactivation of Bacillus subtilis spores under a simulated ozone layer of different thicknesses. Although the UV-C and UV-B regions contribute only 2 % of the entire solar extraterrestrial irradiance, photobiological experiments in space have demonstrated a high mutagenicity and lethality of this UV range to living organisms. The reason for these severe effects of extraterrestrial solar UV radiation - compared to conditions on present-day Earth - lies in the absorption characteristics of the DNA, which is the decisive target for inactivation and mutation induction at this UV range. Being a strong mutagen, UV-radiation is considered as a powerful promoter of biological evolution on the one hand, one the other hand, it may have deleterious consequences to individual cells and organisms, e.g. by causing inactivation, mutations or cancer induction. In response to potential harmful effects of environmental UV radiation, life on Earth has developed several strategies of survival, either avoiding exposure to UV radiation or restoring UV damage. Mechanisms of avoidance of exposure to UV radiation include (i) moving away from the UV radiation into shadowed areas, which requires the development of UV radiation

  17. UV-B radiation and acclimation in timberline plants

    Energy Technology Data Exchange (ETDEWEB)

    Turunen, Minna [Arctic Centre, University of Lapland, PO Box 122, FI-96101 Rovaniemi (Finland)]. E-mail: minna.turunen@ulapland.fi; Latola, Kirsi [Thule Institute, PO Box 7300, FI-90014 University of Oulu, Oulu (Finland)

    2005-10-15

    Research has shown that some plants respond to enhanced UV-B radiation by producing smaller and thicker leaves, by increasing the thickness of epidermis and concentration of UV-B absorbing compounds of their surface layers and activation of the antioxidant defence system. The response of high-altitude plants to UV-B radiation in controlled conditions is often less pronounced compared to low-altitude plants, which shows that the alpine timberline plants are adapted to UV-B. These plants may have a simultaneous co-tolerance for several stress factors: acclimation or adaptation to the harsh climate can also increase tolerance to UV-B radiation, and vice versa. On the other hand, alpine timberline plants of northern latitudes may be less protected against increasing UV-B radiation than plants from more southern latitudes and higher elevations due to harsh conditions and weaker preadaptation resulting from lower UV-B radiation exposure. It is evident that more long-term experimental field research is needed in order to study the interaction of climate, soil and UV-B irradiance on the timberline plants. - More long-term field research is needed to assess the interaction of climate, soil and UV-B on timberline plants.

  18. 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.

  19. 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.

  20. Wastewater matrix effect on disinfection with lp/uv and mp/uv radiation

    OpenAIRE

    Salgado, Ricardo; Hipólito, Cláudia; Galhanas, Dina; Epifâneo, Lisete; Noronha, João Paulo

    2015-01-01

    Com o apoio RAADRI. The disinfection of the wastewater effluents is important to reduce the pathogenic microorganism impact in the environment. UV radiation is one of the technologies used for this purposed. The wastewater characteristics, such as dissolved organic compounds or the presence of suspended solids can affect the efficiency of the faecal coliform bacteria removal in the disinfection process by ultraviolet (UV) radiation technology. This study addresses to see the effect of the ...

  1. The evolutionary response of plants to increased UV-B radiation: Field studies with Arabidopsis thaliana

    International Nuclear Information System (INIS)

    The response of a species to any environmental change is determined by both phenotypic and evolutionary adjustments. To date, the majority of research concerning the response of terrestrial plants to increased UV-B radiation has focused on phenotypic adjustments. Recently we have initiated field studies aimed at assessing genetic variation for UV-B sensitivity within a natural population of Arabidopsis thaliana. This population consists of at least eight discrete genotypes that have been confirmed by RAPD analysis. We used an incomplete block design to assess the impact of UV-B (ambient and ambient + 6 kJ) and PAR (low and high) on these genotypes. The high UV-B treatment caused a significant reduction in fruit number and plant height while the high PAR treatment caused a significant increase in these variables. In addition, there was a marginally significant (p=0.1) UV-B x PAR x maternal line interaction for fruit number, indicating that genetic variation for UV-B sensitivity within this population depends on the PAR environment. The combination of high UV-B and high PAR caused a change in fruit number (relative to the ambient UV-B/high PAR treatment) ranging from an increase of 24% to a decrease of 47%. This range was much smaller in the low PAR treatment. These results indicate the potential for increased UV-B radiation to act as an agent of natural selection within this population

  2. UV Radiation Damage and Bacterial DNA Repair Systems

    Science.gov (United States)

    Zion, Michal; Guy, Daniel; Yarom, Ruth; Slesak, Michaela

    2006-01-01

    This paper reports on a simple hands-on laboratory procedure for high school students in studying both radiation damage and DNA repair systems in bacteria. The sensitivity to ultra-violet (UV) radiation of both "Escherichia coli" and "Serratia marcescens" is tested by radiating them for varying time periods. Two growth temperatures are used in…

  3. Photosynthesis via Mineral Fluorescence in Harsh UV Radiation Environments

    Science.gov (United States)

    Barge, L. M.; Nealson, K.

    2005-12-01

    Before the development of a protective ozone layer about two billion years ago, the surface ultraviolet flux on Earth would have restricted ancient life to environments that offered some protection from direct solar radiation, such as the deep ocean or under or within rocks. In environments where the visible solar radiation would have been reduced to levels too low for photosynthesis, visible fluorescence resulting from UV irradiation of minerals may have provided a useable energy source. We are investigating the possibility that photosynthesis can occur without direct sunlight, if certain minerals are present that can absorb UV radiation and fluoresce in the visible. There are several common minerals(e.g. fluorite, calcite) that emit strong visible radiation under both short- and long-wave UV light, as well as some that only emit visible radiation under specific UV wavelengths. We will test a variety of minerals that fluoresce at wavelengths utilized by microbial chlorophylls and accessory pigments, and by simulating endolithic communities living under a few centimeters or millimeters of rock, we will measure the intensity of fluorescence and UV radiation received at various depths. We plan to simulate a variety of environments where the surface UV radiation may have a significant impact on the survival of life. These include the early Earth and present-day Mars(where the atmosphere would offer little to no protection against biologically damaging UV radiation), as well as extrasolar planets(a terrestrial planet in the habitable zone around an M-type star, for example, would be subject to an intense UV flux due to high flare activity). If mineral fluorescence proves to be a viable survival mechanism for photosynthetic organisms in harsh radiation environments, there are many implications for the study of ancient life on Earth as well as the search for life elsewhere.

  4. Risks of increased UV-B radiation for humans

    International Nuclear Information System (INIS)

    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.)

  5. UV and EB radiation processing in developing countries

    International Nuclear Information System (INIS)

    Ultraviolet and electron beams (EB) are to be considered as complementary technologies in the radiation processing field. In many countries, UV processing is used as the pathfinder for EB. In the developing countries the decision to adopt radiation processing techniques to choose between UV and EB will largely be determined by economics, the availability of the chemists and also skilled personnel to service both lines and equipment. (orig./A.B.)

  6. 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. PMID:26233710

  7. 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.

  8. Role of UV-absorbing compounds in genetic differences in the resistance to UV-B radiation in rice plants

    International Nuclear Information System (INIS)

    Parental cultivars (Oryza sativa L. Japanese lowland cultivars Sasanishiki and Norin 1), F2 plants, and F3 Iines were grown under visible light with or without supplemental UV-B radiation in a phytotron, to determine whether the accumulation of UV-absorbing compounds plays a role in the difference in UV-B resistance between these rice cultivars. The level of UV-absorbance per unit leaf area increased with the UV-B treatuent in all the leaves of these two rice cultivars, but was higher in Sasanishiki than in Norin 1 irrespective of UV-B treatment. An analysis by thin-layer chromatography and the UV-absorption spectra of the extracts did not show any qualitative difference in UV-absorbing compounds in leaf tissues between these two cultivars. There was a significant positive correlation between the level of UV-absorbance per unit leaf area and the fresh weight of aerial parts in the F2 plants exposed to UV-B radiation. Furthermore, the level of UV-absorbance per unit leaf area tended to be higher in the F3 Iines resistant to UV-B radiation than in those sensitive to such radiation regardless of whether these F3 lines were exposed to supplemental UV-B radiation. These results suggest that the differences in UV-B resistance between Sasanishiki and Norin 1 are associated with genetic differences in the level of accumulation of UV-B absorbing compounds in leaf tissues. Based on these results we suggest that the accumulation of UV-B absorbing compounds is an important factor contributing to UV-B resistance in rice cultivars. Since the accumulation of UV-absorbing compounds in leaves appears to minimize the latent negative impact of UV-B radiation on rice production, it may be a useful character to select in ordinary breeding. (author)

  9. Functional genomics of UV radiation responses in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Koch-Paiz, Christine A.; Amundson, Sally A.; Bittner, Michael L.; Meltzer, Paul S.; Fornace, Albert J

    2004-05-18

    The gene expression responses of MCF-7, a p53 wild-type (wt) human cell line, were monitored by cDNA microarray hybridization after exposure to different wavelengths of UV irradiation. Equitoxic doses of UVA, UVB, and UVC radiation were used to reduce survival to 37%. The effects of suramin, a signal pathway inhibitor, on the gene expression responses to the three UV wavelengths were also compared in this model system. UVB radiation triggered the broadest gene expression responses, and 172 genes were found to be consistently responsive in at least two-thirds of independent UVB experiments. These UVB radiation-responsive genes encode proteins with diverse cellular roles including cell cycle control, DNA repair, signaling, transcription, protein synthesis, protein degradation, and RNA metabolism. The set of UVB-responsive genes included most of the genes responding to an equitoxic dose of UVC radiation, plus additional genes that were not strongly triggered by UVC radiation. There was also some overlap with genes responding to an equitoxic dose of UVA radiation, although responses to this lower energy UV radiation were overall weaker. Signaling through growth factor receptors and other cytokine receptors was shown to have a major role in mediating UV radiation stress responses, as suramin, which inhibits such receptors, attenuated responses to UV radiation in nearly all the cases. Inhibition by suramin was greater for UVC than for UVB irradiation. This probably reflects the more prominent role in UVB damage response of signaling by reactive oxygen species, which would not be affected by suramin. Our results with suramin demonstrate the power of cDNA microarray hybridization to illuminate the global effects of a pharmacologic inhibitor on cell signaling.

  10. Effect of enhanced UV-B radiation on motile microorganisms

    International Nuclear Information System (INIS)

    The effect of slightly increased UV-B radiation was studied in four taxonomically very different microorganisms: the gliding prokaryotic cyanobacterium, Phormidium, the unicellular green alga Cosmarium, the flagellate Euglena and the cellular slime mold Dictyostelium. UV-B doses which can be expected as a result of a slight decrease of the protective ozone layer in the stratosphere, do not kill or damage the microorganisms visibly. However, such UV-B doses impair the development, motility and photoorientation of these organisms. Due to the inhibition of these physiological important parameters the organisms cannot respond adequately to the changing factors in their environment, which prevents the survival of the populations. (orig.)

  11. UV background radiation, dust, and gas at high galactic latitude

    International Nuclear Information System (INIS)

    A new analysis of the UV background radiation measurements obtained with the ELZ instrument on board the D2B-Aura satellite is performed at high galactic latitudes (mod(b)>=300) in two bandpasses centered at 1690 A and 2200 A. Correlations of the UV brightnesses with dust tracers are found; the scattering phase function of dust can be derived. Among regions exhibiting a UV flux in excess over the average correlation, an insight is given on the Eridanus region known as a hot spot in soft X-rays. (Auth.)

  12. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation on growth of cucumber

    International Nuclear Information System (INIS)

    The influence of solar UV-A and UV-B radiation at Beltsville, Maryland, on growth and flavonoid content in four cultivars of Cucumis sativus L. (Ashley, Poinsett, Marketmore, and Salad Bush cucumber) was examined during the summers of 1994 and 1995. Plants were grown from seed in UV exclusion chambers consisting of UV-transmitting Plexiglas, lined with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or cellulose acetate to transmit UV-A and UV-B. Despite previously determined differences in sensitivity to supplemental UV-B radiation, all four cultivars responded similarly to UV-B exclusion treatment. After 19–21 days, the four cultivars grown in the absence of solar UV-B (polyester) had an average of 34, 55, and 40% greater biomass of leaves, stems, and roots, respectively, 27% greater stem height, and 35% greater leaf area than those grown under ambient UV-B (cellulose acetate). Plants protected from UV-A radiation as well (Llumar) showed an additional 14 and 22% average increase, respectively, in biomass of leaves and stems, and a 22 and 19% average increase, respectively, in stem elongation and leaf area over those grown under polyester. These findings demonstrate the extreme sensitivity of cucumber not only to present levels of UV-B but also to UV-A and suggest that even small changes in ozone depletion may have important biological consequences for certain plant species. (author)

  13. UV-induced immune suppression and photocarcinogenesis: Chemoprevention by dietary botanical agents

    OpenAIRE

    Santosh K. Katiyar

    2007-01-01

    Studies of immune-suppressed transplant recipients and patients with biopsy-proven skin cancer have confirmed that ultraviolet (UV) radiation-induced immune suppression is a risk factor for the development of skin cancer in humans. UV radiation suppresses the immune system in several ways. The UVB spectrum inhibits antigen presentation, induces the release of immunosuppressive cytokines, and elicits DNA damage that is a molecular trigger of UV-mediated immunosuppression. It is therefore impor...

  14. 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

  15. The effect of exposure to enhanced UV-B radiation on the penetration of monochromatic and polychromatic UV-B radiation in leaves of Brassica napus

    International Nuclear Information System (INIS)

    Using quartz optical fibres, penetration of both monochromatic (310 nm) and polychromatic UV-B (280–320 nm) radiation in leaves of Brassica napus L. (cv. Ceres) was measured. Plants were grown under either visible light (750 μmol m−2 s−1 photosynthetically active radiation) or with the addition of 8. 9 KJ m−2 day−1 biologically effective UV-B (UV-BBE) radiation. Results showed that of the 310 nm radiation that penetreated the leaf, 90% was within the intial one third of the leaf with high attenuation in the leaf epidermis, especially in UV-treated plants. Polychromatic UV-B radiation, relative to incident radiation, showed a relatively uniform spectral distribution within the leaf, except for collimated radiation. Over 30% of the UV-screening pigments in the leaf, including flavonoids, were found in the adaxial epidermal layer, making this layer less transparent to UV-B radiation than the abaxial epidermis, which contained less than 12% of the UV-screening pigments. UV-screening pigments increased by 20% in UV-treated leaves relative to control leaves. Densely arranged epicuticular wax on the adaxial leaf surface of UV-treated plants may have further decreased penetration of UV-B radiation by reflectance. An increased leaf thickness, and decreases in leaf area and leaf dry weight were also found for UV-treated plants. (author)

  16. Tuning the SMS spectrum based on UV radiation

    Science.gov (United States)

    Zhong, Di; Tian, Ye; Zhang, Jianzhong; Sun, Weimin; Yuan, Libo

    2014-05-01

    We propose a fine spectrum-tuning scheme of the single-multi-single mode fiber (SMS) structure, realised by using UV radiation to modify the propagation constants of different modes in Multi-mode fiber of SMS. The primary experiments also demonstrated. It expect to have applications in the design of SMS based optical filters and sensors.

  17. Natural Microbial UV Radiation Filters - Mycosporine-like Amino Acids

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Temina, M.; Tolstikov, A. G.; Dembitsky, V. M.

    2004-01-01

    Roč. 49, č. 4 (2004), s. 339-352. ISSN 0015-5632 Institutional research plan: CEZ:AV0Z5020903 Keywords : uv radiation * maas * ultraviolet-b Subject RIV: EE - Microbiology, Virology Impact factor: 1.034, year: 2004

  18. UV Radiation Exposure of Composite Specimens, using the SPHERE

    OpenAIRE

    CORDELLE, Aurélie; LABORATOIRE CENTRAL DES PONTS ET CHAUSSEES - LCPC; NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY - NIST; ECOLE NATIONALE SUPERIEURE DE MECANIQUE ET D'AEROTECHNIQUE DE POITIERS - ENSMA

    2010-01-01

    The objectives of the research are to provide insight into the mechnical behavior of a unidirectional pultruded E-glass/vinylester composite, submitted to UV radiation exposure over several periods of time. The degradation of exposed samples will be carried out using the change of both local modulus and hardness.

  19. Combined effects, ionizing radiation plus other agents

    International Nuclear Information System (INIS)

    It is clear from cell studies, and confirmed in a general way by animal sudies, that radiation produces effects that are interactive with those due to other physical agents, chemicals of various types, and viruses. Our understanding is limited, however, in respect to the mechanisms of action in cells and, accordingly, even less penetrating in respect to our comprehension of effects in animals. Thus, the conclusion follows at this time, that we are unable to predict responses in humans due to combined action because of our incomplete understanding of individual and combined responses of radiation and other agents in experimental systems. The study of possible public health hazards due to the combined effects of radiation plus other agents is one that should be coverged upon simultaneously by the laboratory investigator and the epidemiologist-public health specialist. What is clear is the likelihood that agents biologically active in their own right may interact. Indeed, an important and significant guiding principle can be extracted from current knowledge. Relative to induced cellular changes, agents that register lesions in the genetic substance of a cell are likely to produce interactive effects. Such effects may become expressed in individual cells, in tissues, or in whole organisms

  20. Beyond UV radiation: a skin under challenge.

    Science.gov (United States)

    Dupont, E; Gomez, J; Bilodeau, D

    2013-06-01

    Since ancient times, human beings have been trying to protect their skin against the adverse effects of the sun. From the first mineral sunscreens used by Egyptians, to the current more sophisticated ultraviolet (UVA/UVB) organic sunscreens, progress has been made in terms of sun protection and deeper knowledge of skin physiology has been acquired in the process. The solar spectrum is composed of radiations of various wavelengths having specific, as well as overlapping effects on skin. UVB is mainly responsible for sunburn and DNA dimer formation that can lead to mutation. UVA generates oxidative reactions affecting DNA, proteins and lipids, and is also immunosuppressive. Recently, visible light and infrared radiation (IR) have been associated with oxidative damage and IR has been additionally linked to adverse heat effects on skin. Numerous other extrinsic factors, related to environment and lifestyle, also affect the appearance of skin, precipitating ageing. New molecular mechanisms linking sun and environmental factors to skin ageing have been identified: IR affects mitochondrial integrity and specific heat receptors also mediate some of its effects, tryptophan is a chromophore for UVB, and the aryl hydrocarbon receptor (AhR) is activated by light and xenobiotics to alter skin physiology. Integrating all these new elements is changing the way we think about skin extrinsic ageing. Is UVA/UVB sunscreen protection still enough for our skin? PMID:23406155

  1. Intermittent Jolts of Galactic UV Radiation Mutagenetic Effects

    CERN Document Server

    Scalo, J M; Williams, P; Scalo, John M.; Williams, Peter

    2001-01-01

    We estimate the frequency of intermittent hypermutation events and disruptions of planetary/satellite photochemistry due to ultraviolet radiation from core collapse supernova explosions. Calculations are presented for planetary systems in the local Milky Way, including the important moderating effects of vertical Galactic structure and UV absorption by interstellar dust. The events are particularly frequent for satellites of giant gas planets at \\gtrsim 5-10 AU distance from solar-type parent stars, or in the conventional habitable zones for planets orbiting spectral type K and M parent stars, with rates of significant jolts about 10^3 - 10^4 per Gyr. The steep source spectra and existing data on UVA and longer-wavelength radiation damage in terrestrial organisms suggest that the mutational effects may operate even on planets with ozone shields. We argue that the mutation doubling dose for UV radiation should be much smaller than the mean lethal dose, using terrestrial prokaryotic organisms as our model, and ...

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

    International Nuclear Information System (INIS)

    The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H2O2, UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO2, UV-C/H2O2/TiO2 and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5 x 10-3 mol Einstein-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 TiO2 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.

  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. Effect of far-UV and near-UV radiation on the cell surface charge of the protozoan Tritrichomonas foetus

    International Nuclear Information System (INIS)

    Cell electrophoresis was used to detect the effect of far-UV or near-UV radiation on the cell surface charge of the pathogenic protozoan Tritrichomonas foetus. Either far-UV or near-UV radiation interfered with the surface charge of T. foetus at fluences which inhibited cell growth by 50%. Both UV-radiations induced a significant decrease on surface charge of T. foetus, as evaluated by measurement of its electrophoretic mobility (EPM). Determinations of EPM of protozoa in solution of low ionic strength indicated that the decrease in the EPM induced by far-UV is much less pronounced that that observed for near-UV or control cells. (author)

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

    International Nuclear Information System (INIS)

    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. (Author) 10 refs

  6. 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

  7. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Penetration of UV Radiation in the Earth's Oceans

    Science.gov (United States)

    Mitchell, B. Greg; Lubin, Dan

    2005-01-01

    This project was a collaboration between SIO/UCSD and NASA/GSFC to develop a global estimation of the penetration of UV light into open ocean waters, and into coastal waters. We determined the ocean UV reflectance spectra seen by satellites above the atmosphere by combining existing sophisticated radiative transfer models with in situ UV Visible data sets to improve coupled radiance estimates both underwater and within the atmosphere. Results included improved estimates of surface spectral irradiance, 0.3-1.0 micron, and estimates of photosynthetic inhibition, DNA mutation, and CO production. Data sets developed under this proposal have been made publicly available via submission to the SeaWiFS Bio-Optical Archive and Storage System. Numerous peer-reviewed publications and conference proceedings and abstracts resulted from the work supported by this research award.

  10. Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms.

    Science.gov (United States)

    Paul, Nigel D; Moore, Jason P; McPherson, Martin; Lambourne, Cathryn; Croft, Patricia; Heaton, Joanna C; Wargent, Jason J

    2012-08-01

    Solar ultraviolet (UV)-B radiation (280-315 nm) has a wide range of effects on terrestrial ecosystems, yet our understanding of how UV-B influences the complex interactions of plants with pest, pathogen and related microorganisms remains limited. Here, we report the results of a series of experiments in Lactuca sativa which aimed to characterize not only key plant responses to UV radiation in a field environment but also consequential effects for plant interactions with a sap-feeding insect, two model plant pathogens and phylloplane microorganism populations. Three spectrally modifying filters with contrasting UV transmissions were used to filter ambient sunlight, and when compared with our UV-inclusive filter, L. sativa plants grown in a zero UV-B environment showed significantly increased shoot fresh weight, reduced foliar pigment concentrations and suppressed population growth of green peach aphid (Myzus persicae). Plants grown under a filter which allowed partial transmission of UV-A radiation and negligible UV-B transmission showed increased density of leaf surface phylloplane microbes compared with the UV-inclusive treatment. Effects of UV treatment on the severity of two plant pathogens, Bremia lactucae and Botrytis cinerea, were complex as both the UV-inclusive and zero UV-B filters reduced the severity of pathogen persistence. These results are discussed with reference to known spectral responses of plants, insects and microorganisms, and contrasted with established fundamental responses of plants and other organisms to solar UV radiation, with particular emphasis on the need for future integration between different experimental approaches when investigating the effects of solar UV radiation. PMID:22150399

  11. Radiation Chemistry Studies on Chemotherapeutic Agents

    DEFF Research Database (Denmark)

    Gohn, M.; Getoff, N.; Bjergbakke, Erling

    1977-01-01

    Adrenalin has been studied as a model radiation protective agent by means of pulse radiolysis in aqueous solutions. The rate constants for the reactions of adrenalin with e–aq and OH were determined : k(e–aq+ adr—NH+2)= 7.5 × 108 dm3 mol–1 s–1, k(e–aq+ adr—NH)= 2.5 × 108 dm3 mol–1 s–1, and k(OH +...

  12. UV- and gamma-radiation sensitive mutants of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Arabidopsis seedlings repair UV-induced DNA damage via light-dependent and -independent pathways. The mechanism of the ''dark repair'' pathway is still unknown. To determine the number of genes required for dark repair and to investigate the substrate-specificity of this process we isolated mutants with enhanced sensitivity to UV radiation in the absence of photoreactivating light. Seven independently derived UV sensitive mutants were isolated from an EMS-mutagenized population. These fell into six complementation groups, two of which (UVR1 and UVH1) have previously been defined. Four of these mutants are defective in the dark repair of UV-induced pyrimidine [6-4] pyrimidinone dimers. These four mutant lines are sensitive to the growth-inhibitory effects of gamma radiation, suggesting that this repair pathway is also involved in the repair of some type of gamma-induced DNA damage product. The requirement for the coordinate action of several different gene products for effective repair of pyrimidine dimers, as well as the nonspecific nature of the repair activity, is consistent with nucleotide excision repair mechanisms previously described in Saccharomyces cerevisiae and nonplant higher eukaryotes and inconsistent with substrate-specific base excision repair mechanisms found in some bacteria, bacteriophage, and fungi. (author)

  13. uv radiation curable paints. Topical report on material identification

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-13

    The program for the development of ultraviolet radiation curing of paints for application on preformed structures is discussed. The starting point of this program was the matching of resins, photoinitiators, and pigments which will result in coatings that can be cured by ultraviolet radiation. The initial work was the identification of reactive diluents and base resins that are sensitive to the uv curing process. The reactive monomeric diluents tested included multifunctional acrylates, monofunctional acrylates, and non-acrylic unsaturated esters. The end point will be the application of these coatings to prefabricated metal structures to demonstrate the viability of this technique in producing commercially acceptable painted products. These uv curable paints should produce films that are hard, adherent, and opaque at a nominal thickness of one mil (0.001 inch).

  14. Effect of UV-B Radiation on the Leaf Growth of Rice Seedling

    International Nuclear Information System (INIS)

    Rice seedlings were used to examine the effect of UV-B radiation on leaf elongation and development. Leaf elongation in both rice seedlings showed differently depending on each leaf age. UV-B radiation strongly reduced leaf elongation, 58-66% compared to without UV-B radiation, of two rice seedlings, therefore, those seedlings could not grow further

  15. Intermittent Jolts of Galactic UV Radiation: Mutagenetic Effects

    OpenAIRE

    Scalo, John M.; Wheeler, J. Craig; Williams, Peter

    2001-01-01

    We estimate the frequency of intermittent hypermutation events and disruptions of planetary/satellite photochemistry due to ultraviolet radiation from core collapse supernova explosions. Calculations are presented for planetary systems in the local Milky Way, including the important moderating effects of vertical Galactic structure and UV absorption by interstellar dust. The events are particularly frequent for satellites of giant gas planets at \\gtrsim 5-10 AU distance from solar-type parent...

  16. The chemistry of UV and BE radiation curing

    International Nuclear Information System (INIS)

    The application of photopolymerisation (UV) and electron beams (EB) technologies in radiation rapid cure (PRC) processing is discussed. The chemistry associated with such reactions and the mechanisms of the processes are treated. The occurrence of concurrent grafting to substrate with radiation curing of films is shown to be an advantage in enhancing the properties of certain finished products. The parameters influencing the optimum grafting yield in such PRC processes are discussed. In many applications, the chemistry of such processes combined with the machine, specially for EB is shown. (author)

  17. The chemistry of UV and EB radiation curing

    International Nuclear Information System (INIS)

    The application of photopolymerisation (UV) and electron beam (EB) technologies in radiation rapid cure (RRC) processing is discussed. The chemistry associated with such reactions and the mechanisms of the processes are treated. The occurrence of concurrent grafting to substrate with radiation curing of film is shown to be an advantage in enhancing the properties of certain finished products. The parameters influencing the optimum grafting yield in such RRC processes are discussed. In many applications, the chemistry of the process combined with the machine, expecially for EB, is shown a so-called ''turn-key'' operation. (author)

  18. Readings of Polysulphone Film after Fractionated and Continuous Exposures to UV Radiation and Consequences for the Calculation of the Reading Resulting from Polychromatic UV Radiation

    International Nuclear Information System (INIS)

    The reading of polysulphone film (PSF), resulting from fractionated exposures to monochromatic UV radiation, was compared with the response to continuous irradiations of the same radiant exposure and wavelength. Also studied was the effect of a pre-exposure to monochromatic UV radiation on the reading resulting from a subsequent irradiation at a different wavelength. The results are used for a physical description of the detector reading resulting from given spectral radiant exposures. This allows readings of PSF after exposures to polychromatic UV radiation to be calculated. The description was tested for solar UV radiation at ground level and good agreement between experimental and calculated detector readings was achieved. (author)

  19. Measuring solar UV radiation with EBT radiochromic film

    Energy Technology Data Exchange (ETDEWEB)

    Butson, Ethan T [Illawarra Grammar School, (TIGS), Western Ave, West Wollongong, NSW (Australia); Cheung Tsang; Yu, Peter K N; Butson, Martin J, E-mail: diamonds.for.you@hotmail.co [Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong (Hong Kong)

    2010-10-21

    Ultraviolet radiation dosimetry has been performed with the use of a radiochromic film dosimeter called Gafchromic EBT for solar radiation exposure. The film changes from a clear colour to blue colour when exposed to ultraviolet radiation and results have shown that the colour change is reproducible within {+-}10% at 5 kJ m{sup -2} UV exposure under various conditions of solar radiation. Parameters tested included changes in season (summer versus winter exposure), time of day, as well as sky conditions such as cloudy skies versus clear skies. As the radiochromic films' permanent colour change occurs in the visible wavelengths the film can be analysed with a desktop scanner with the most sensitive channel for analysis being the red component of the signal. Results showed that an exposure of 5 kJ m{sup -2} (approximately 1 h exposure in full sun during summer) produced an approximate 0.28 change in the net OD when analysed in reflection mode on the desktop scanner which is significant darkening. The main advantages of this film type, and thus the new EBT2 film which has replaced EBT for measurement of UV exposure, is the visible colour change and thus easy analysis using a desktop scanner, its uniformity in response and its robust physical strength for use in outside exposure situations. (note)

  20. Measuring solar UV radiation with EBT radiochromic film

    International Nuclear Information System (INIS)

    Ultraviolet radiation dosimetry has been performed with the use of a radiochromic film dosimeter called Gafchromic EBT for solar radiation exposure. The film changes from a clear colour to blue colour when exposed to ultraviolet radiation and results have shown that the colour change is reproducible within ±10% at 5 kJ m-2 UV exposure under various conditions of solar radiation. Parameters tested included changes in season (summer versus winter exposure), time of day, as well as sky conditions such as cloudy skies versus clear skies. As the radiochromic films' permanent colour change occurs in the visible wavelengths the film can be analysed with a desktop scanner with the most sensitive channel for analysis being the red component of the signal. Results showed that an exposure of 5 kJ m-2 (approximately 1 h exposure in full sun during summer) produced an approximate 0.28 change in the net OD when analysed in reflection mode on the desktop scanner which is significant darkening. The main advantages of this film type, and thus the new EBT2 film which has replaced EBT for measurement of UV exposure, is the visible colour change and thus easy analysis using a desktop scanner, its uniformity in response and its robust physical strength for use in outside exposure situations. (note)

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

    Czech Academy of Sciences Publication Activity Database

    Štroch, Michal; Materová, Z.; Vrábl, D.; Karlický, Václav; Šigut, Ladislav; Nezval, J.; Špunda, Vladimír

    2015-01-01

    Roč. 96, nov (2015), s. 90-96. ISSN 0981-9428 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : barley (Hordeum vulgare L.) * chlorophyll fluorescence * photosynthesis * photosynthetic pigments * UV-A radiation * UV-B radiation Subject RIV: EH - Ecology, Behaviour Impact factor: 2.756, year: 2014

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

    International Nuclear Information System (INIS)

    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 O2 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

  3. 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.

  4. Responses of antioxidant defense system of Lespedeza davurica to enhanced UV-B radiation

    International Nuclear Information System (INIS)

    The objective of this study was to investigate the effects of different UV-B radiation intensity (CK, T1, T2) on antioxidant defense system and other related indicators of Lespedeza davurica (Laxm.) Schindl. Malonaldehyde (MDA), ascorbic acid (AsA) and carotenoid (Car) contents, as well as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities of leaves from Lespedeza davurica under different UV-B radiation intensity were investigated. Samples were collected once every three days. The UV-B treatment was continued 15 days. Result indicated that SOD and POD activities decreased, APX and POD activities increased with UV-B radiation enhanced during the whole treatment time. SOD, POD and CAT activities decreased with UV-B radiation intensity increasing. APX activity increased during the first 9-day treatment with radiation intensity increasing then decreased with radiation intensity increasing. UV-B radiation increased AsA content, decreased Car content. Both AsA and Car contents decreased with radiation intensity increasing when compared with control. O2- and MDA increased with radiation intensity increasing. All other tested indicators increased except SOD and POD activity as well as AsA content decreased after UV-B radiation treatment. Comprehensive evaluation of subordinate function showed that UV-B radiation reduced the antioxidant capacity of Lespedeza davurica, and the antioxidant capacity decreased with UV-B radiation intensity increasing. (author)

  5. 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.

  6. 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...... symbionts (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...

  7. 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.

  8. Effects of UV and microwave radiation on biological material

    International Nuclear Information System (INIS)

    For the present study, ten publications on the effect of UV radiation were analyzed. In vitro tests were carried out with one biological substance and seven different human or animal organs and biocytocultures. In vivo, three bacterial strains were irradiated and four irradiation experiments were carried out on mice. As to the effect of microwave radiation, eleven publications were analyzed. In vitro tests were carried out with one biological substance and three animal organs. In vivo, one bacterial strain was irradiated and eight irradiation experiments were carried out on different types of animals. The study's aim was to obtain a survey on biochemical changes of the organisms. Phenomenological changes were given only when the corresponding articles contained further investigation results. Behavioral changes were not taken into account. The results published by the authors of the original papers were compiled in a kind of dictionary. All relevant data are listed in a defined order. (orig.)

  9. Secondary UV radiation from biota as a proof of radiation hormesis and Gurwitsch phenomena

    International Nuclear Information System (INIS)

    High (large) and low (small) doses of ionizing radiation consistently induce opposite physiologic effects in biological systems. The effects of low doses cannot be inferred by interpolation between the result from groups exposed to high doses and controls irradiated only by Natural Background Radiation. Stimulation NBR ('bio-positive') effects by low-level doses of ionizing radiation is called radiation hormesis. It is still a controversial idea; however it was found that some biological objects (yeast, sees, animals) after γ-irradiation by low-level doses (10-50 times more NBR) can increase their development. The results of the researches demonstrate that the excitation of living systems by ionizing radiation (high energy, low doses) produces among other hydrogen peroxide which initiates prolonged secondary emission that can influence biota and activate many important processes in biological systems. On the other hand it is well known that after water irradiation by ionizing radiation as the product of radiolysis concentration of hydrogen peroxide has been received. The spectral analysis of this secondary emission confirmed the contribution of the UV component to the total emission. This secondary radiation can play a very important role in the intercellular communication. The influence of hydrogen peroxide on glycine has been examined. I have measured secondary emission from Gly using the Single Photon Counting device SPC. The data obtained made possible at least a partial understanding of the radiation hormesis phenomenon and suggest closer relationship to mitogenetic radiation. I propose deexcitation processes in biomolecules as a common denominator of UV and ionizing radiation interacting with living cells, underlying both radiation hormesis and mitogenetic effect. Based on the above experiments and other authors' reports it is postulated that low-level doses of ionizing radiation through radiolysis products (among others hydrogen peroxide) generate UV

  10. Antioxidant responses of damiana (Turnera diffusa Willd to exposure to artificial ultraviolet (UV radiation in an in vitro model: part I; UV-C radiation

    Directory of Open Access Journals (Sweden)

    Lluvia de Abril Alexandra Soriano-Melgar

    2014-05-01

    Full Text Available Introduction: Ultraviolet type C (UV-C radiation has higher energy than the UV-B radiation and has been less studied because it is completely absorbed by the ozone layer. However, artificial UV-C radiation can generate diverse modifications in the plants. Given that exposure to UV-C for short periods of time increases the antioxidant content, improving the appearance and shelf-life of products, its potential application in postharvest treatments to modify the antioxidant content of medicinal plants, such as damiana (Turnera diffusa, is novel and relevant. Objective: To determine the effects of UV-C radiation on enzymatic and non-enzymatic antioxidant defenses, as well as oxidative damage levels, in damiana (Turnera diffusa plants in vitro. Results: UV-C radiation decreased superoxide dismutase (SOD, EC 1.15.1.1 and total peroxidases (POX, EC 1.11.1 activities, the concentration of chlorophylls (a and b, carotenes, vitamin C, and total antioxidant capacity. UV-C radiation increased the phenolic compound levels in damiana. Loss of antioxidant defenses was higher in damiana plants exposed to higher UV-C doses and/or for longer periods. This study suggests that UV-C radiation induces oxidative stress, evidenced as increased protein carbonyls and phenolic compound content, in damiana (T. diffusa. Conclusion: Low dose, short exposure to UV-C stimulates phenolic compound content in damiana. Thus, controlled UV-C treatments could be used as postharvest treatment to increase phenolic compound content in damiana plants.

  11. Radiation Chemistry Studies on Chemotherapeutic Agents

    DEFF Research Database (Denmark)

    Gohn, M.; Getoff, N.; Bjergbakke, Erling

    1977-01-01

    Adrenalin has been studied as a model radiation protective agent by means of pulse radiolysis in aqueous solutions. The rate constants for the reactions of adrenalin with e–aq and OH were determined : k(e–aq+ adr—NH+2)= 7.5 × 108 dm3 mol–1 s–1, k(e–aq+ adr—NH)= 2.5 × 108 dm3 mol–1 s–1, and k......(OH + adr)= 2.2 × 1010 dm3 mol–1 s–1(pH = 9.2). e–aq attacks the amino group by splitting off methylamine, whereas OH and O–aq lead to the formation of the corresponding adducts of the cyclohexadienyl type. OH radicals can also abstract an electron from an O– group at pH > 8....

  12. UV radiation and health: prevention in school; UV-Strahlung und Gesundheit: Praevention in der Schule

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, B.U. [Bundesamt fuer Gesundheit (Switzerland)

    2004-07-01

    It is well known that children's skin and eyes are very sensitive to UV radiation, and that sunburn during childhood increases the risk of skin cancer later in life. Because of these facts and the easier influence to attitudes and behaviour at a young age, prevention in school becomes an important issue. There are difficulties and chances pointed out for prevention in schools. It is stated on the basis of a running prevention program for primary and secondary school in Switzerland how a concrete conversion can look. Teaching materials and worksheets for the different school stages form the principal item in this program. Described is the total concept, the method for the development of the materials as well as the experiences after three-year application. (orig.)

  13. Long-term solar UV radiation reconstructed by Artificial Neural Networks (ANN

    Directory of Open Access Journals (Sweden)

    U. Feister

    2008-01-01

    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. 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.

  14. Mutagenic action of UV radiation on lambda prophage

    International Nuclear Information System (INIS)

    The lethal and mutagenic effects of UV radiation on a thermoinducible prophage lambda cI857 were studied in the wild-type cells of Escherichia coli K12 and in 9 repair-deficient mutants: uvrA6, uvrD3, uvrE502, polA1, recA13, lexA102, recB21recC22sbcB15, recB21recC22sbcB15recF143 and recB21recC22sbcB15recL152. After UV irradiation, lysogenic cells were submitted to thermal induction either immediately or after 90 min incubation in broth at 320. We scored for temperature-independent c-mutants of lambda phage that formed clear plaques at 320. After immediate thermoinduction (ITI) of prophage the phenomena were similar to W-reactivation (WR) and W-mutagenesis (WM) of UV-irradiated extracellular lambda phage infecting UV-irradiated host cells. In the wild-type host a shoulder was manifested on survival curves, and the frequency of c mutations significantly increased, attained a sharp maximum at 120 J/m2 and subsequently decreased. The mutagenic action on prophage remained normal in uvrA, uvrD, polA and recBCsbcB mutants, but was strongly reduced in uvrE-, recBC-sbcB-recF- and recBC-sbcB-recL- lysogens. After delayed thermoinduction (DTI) of prophage in the wild-type host, survival increased, but mutation frequency declined (in comparison with ITI). DTI had the same effects in repair-deficient mutants recBCsbcB, uvrD and polA. The delay in thermoinduction of prophage had no effect on the uvrA- lysogen but a slight effect in uvrE- and recBC-sbcB- recF- hosts. In the recBC-sbcB-recL- lysogen the delay in prophage induction had an opposite, i.e. stimulating, effect on UV mutagenesis. In recA- or lexA- hosts the prophage yielded no c mutants after either ITI or DTI. (orig.)

  15. Effects of UV-B radiation on the growth interaction of Ulva pertusa and Alexandrium tamarense

    Institute of Scientific and Technical Information of China (English)

    CAI Heng-jiang; TANG Xue-xi; ZHANG Pei-yu; DONG Dong; QU Liang

    2005-01-01

    Enhanced UV-B(280- 320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects of UV-B radiation on interaction of macro-algae and micro-algae were investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the materials in this study.The results demonstrated that UV-B radiation could inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were both mono-cultured, and the growth inhibition of algae was more significant with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit the growth of Ulva pertusa in mixed culture, and the growth inhibition was more significant when increasing the initial cell density. However, Ulva pertusa could inhibit the growth of Alexandriurm tamarense in early phase and stimulate the growth in latter phase when they were grown in mixed culture. Lower initial cell density(102 cell/mi) of Alexandriurm tamarense could inhibit the growth of Ulva pertusa under UV-B radiation treatment,however, with the initial cell density increasing(103 and 104 cell/ml), the growth of Ulva pertusa was stimulated under lower dose of UV-B radiation and inhibited under higher dose of UV-B radiation by Alexandrium tamarense.Compared with that in mixed culture, Ulva pertusa showed more positive inhibition to the growth of Alexandrium tamarense under UV-B radiation treatment.

  16. Effect of UV radiation on the growth and breakdown voltage of anodic oxide films on niobium

    International Nuclear Information System (INIS)

    Formation rates of anodic Nb2O5 films grown under galvanostatic conditions decrease in the presence of UV radiation, unlike those grown in the absence of UV radiation. This may be due to the development of a positive space charge near the solution/oxide interface which is responsible for an increase in electronic current in the film during its formation. Value of breakdown voltage also increases in the presence of UV radiations. The effect of current density and resistivity of the solution upon the breakdown voltage, both in the presence and absence of UV radiation, is discussed in terms of Ikonopisov theory of breakdown voltage. (author). 19 refs., 6 figs

  17. Appraisal of alternative skin model for the study of epidermal restoration following exposure to various environmental stress agents: ionising radiation and UV B; Evaluation d'un modele alternatif de peau dans l'etude de l'atteinte epidermique apres exposition a differents agents de stress environnementaux: rayonnements ionisants (RI) et ultra-violets B (UVB)

    Energy Technology Data Exchange (ETDEWEB)

    Isoir, M

    2006-06-15

    Human skin is a major target tissue for ionising radiation (IR) and UV B. We developed a skin explant model and used 2 types of keratinocytes to study survival and oxidative stress induced by these radiations. We examined oxidative damages by measuring R.O.S. produced and cellular anti-oxidant defenses induced. We observed into skin exposed to IR a modulation of genes expression implied in the control of oxidative stress, confirmed by the decrease of catalase, glutathione peroxidase and superoxide dismutase enzymatic activities. The imbalance observed between anti- and pro-apoptotic genes expression shows that keratinocytes apoptosis may be partly dependent on radio-induced R.O.S. production. We showed the difference of radiosensitivity between N.H.E.K. and Ha Ca.T., which may be linked to their differential oxidative responses. In addition, during re-epithelialising, we demonstrated that activated N.H.E.K. after IR express keratin 6, release pro-inflammatory cytokines and proliferate, without modification of their differentiation. Treatment of N.H.E.K. with geranyl geranylacetone (G.G.A.) has a beneficial effect on their radio-induced activation by increasing IL-1 release, their migration in scrapped area and their survival. G.G.A. has an anti apoptotic ability (induction of Hsp70- caspase-3 pathway) and migratory properties (P38/RhoA activation) on N.H.E.K., but after IR, only caspase-3 pathway is induced. This work thus contributes to the understanding of cutaneous damages after IR and G.G.A. mechanism of action which accelerates re-epithelialising. (author)

  18. 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

  19. Regulation of immune suppression induced by UV radiation

    International Nuclear Information System (INIS)

    Full text: Exposure of the skin of mice and men to increasing doses of UV radiation causes erythema, blistering, accelerated photoageing, DNA lesions and photocarcinogenesis. Moderate exposure also suppresses T cell-mediated immune function, a defect which is a prerequisite for the promotion or outgrowth phase of the UV-initiated tumour, and which is accompanied by dysregulated cutaneous cytokine patterns. A major cutaneous photoreceptor for the immunosuppression is epidermal urocanic acid (UCA). Naturally occurring trans-UCA photoisomerises in the stratum corneum and epidermis to cis-UCA, in a direct reaction. Cis-UCA has been found to have local and systemic immunosuppressive properties. The action spectrum for the photoimmuno-suppression is maximal in the UVB (280 320nm) waveband. However longer wavelength UVA (320-400nm), which interacts with skin predominantly via oxidative reactions, is not immunosuppressive at environmental exposure doses, and unexpectedly can provide protection from UVB-immunosuppression. We find that UVA protective exposure prevents the major UVB-alterations to the cytokine array. In addition, UVA (but not UVB) exposure induces cutaneous haem oxygenase (HO) activity, an endogenous antioxidant enzyme. HO is known to be redox-regulated, and to be the major stress protein induced in cultured fibroblasts by UVA. We find that UVA-immune protection is dependent on the induced HO; that enhanced HO activity following UVA is cytokine-dependent; and that the induced HO acts by inhibiting the immunosuppressive potential of cis-UCA. Thus oxidant states resulting predominantly from UVA irradiation, while apparently immunologically innocuous, seem to actively upregulate this defensive HO response. These studies have therefore revealed interactions between different UV wavebands important for immune regulation both in the skin and systemically, which may have a critical bearing on the carcinogenic outcome in chronically exposed skin, and offer the

  20. 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...

  1. Surface Coating of Musa Brachycarpa Trunk Using UV-Radiation

    International Nuclear Information System (INIS)

    An experiment on UV-curing of surface coating of Musa brachycarpa was carried out using urethane acrylate polymer films. Radiation curable material was the mixture of urethane acrylate resin, tripropylene glycol diacrylate monomer (TPGDA) and radical photo initiator of 2,2-dimethyl -2-hydroxy acetophenone. The TPGDA concentrations in the mixture with urethane acrylate resin were 60; 70 and 80% weight, Whereas concentrations of photo initiator were varied at the level 1.5:2.0 and 2.5% by weight based on resin and monomer mixture. Irradiation was conducted by using 80 Watt/cm intensity UV-light at the conveyor speed of 2: 3 and 4 m/min. Analysis and film properties observed were IR spectrum, gel fraction, hardness, abrasion resistance, glossy and chemical, solvent and stain resistances. Films have good resistances against 1% sodium carbonate, 5% acetic acid, 50% alcohol, thinner and red, blue and black permanent marker, except against 10% sodium hydroxide and 10% sulfuric acid. Optimum condition was achieved at the photo initiator concentration level of 2% and conveyor speed of 3 m/min

  2. Effects and mechanism of UV-B radiation on rice growth

    International Nuclear Information System (INIS)

    The enhancement of UV-B radiation influences the growth of rice and physiology in different levels and this performances as changes in morphology destroyed photosynthetic system unstable anti-oxidation system changes of endogenous hormone content exacerbated rice diseases decreased biomass and developmental stage delay. Through the establishment of the response index we can evaluate the varietal differences in responses of the rice to UV-B radiation. Reasons for such varietal differences were differences in rice gene physiology and morphology developmental stage and environmental factors. The main mechanism in responses of the rice to UV-B radiation was induction of flavonoid compounds and accumulation of anthocyanins. Based on the analysis of the influence of enhanced UV-B radiation to rice and the varietal differences in responses to UV-B radiation and mechanism of rice the direction of the further research about the relationship between the rice and UV-B was put forward

  3. Effects of UV radiation on the RNA/DNA ratio of Copepods from Antarctica and Chile

    Institute of Scientific and Technical Information of China (English)

    Paulo F. Lagos; M. Jesús Valdés; Karen Manríquez

    2015-01-01

    The effect of ultraviolet (UV) radiation on marine organisms has been an important focus of recent research, with depletion of the ozone layer resulting in increased UV radiation at high latitudes. Several studies have identiifed negative impacts of UV radiation on the biology of zooplanktonic organisms. This study used the RNA/DNA ratio as a measure of stress in copepod assemblages from Fíldes Bay in Antarctica and Quintay Bay on the central coast of Chile, two areas with high UV radiation but different photobiologic histories. Controlled time-light experiments were performed with copepods from the two locations, exposing them to white light, UV light, or darkness. The results showed different responses to UV radiation. Copepods from Fíldes Bay showed a slow metabolic response to UV radiation after 4 and 8 h of exposure. Copepods from Quintay Bay showed a fast metabolic response after 4 h of exposure (4 orders of magnitude higher than that for Fíldes Bay copepods) followed by a rapid return toward baseline after 8 h of exposure. These different responses probably relfect the time the copepod assemblages have been exposed to increased UV radiation and the extent of adaptive stress responses to cope with that increased UV radiation. The results of this study show that the RNA/DNA ratio is a useful indicator of the physiologic status of marine organisms and is a useful tool to measure the effects of changing environmental conditions on marine ecosystems, such as those associated with global climate change.

  4. Radiation chemical oxidation of propen under the influence of UV- and gamma radiation

    International Nuclear Information System (INIS)

    The oxidation of propen is studied in the liquid state under the influence of electromagnetic radiation using hydrogenperoxide, organic hydroperoxides and oxygen. In this investigation propen oxide is of main interest. The study of systems with oxygen is based on the concept that the formation of hydroperoxide from organic oxygen compounds is enhanced by irradiation, thus favouring an in situ method for expoxidation with hydroperoxides. The influence of UV-radiation from high and low pressure mercury discharge lamps and 60Co gamma radiation has been studied as well as the effect of solvents and catalysers, which are resolved in the system. (orig./WBU)

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

    International Nuclear Information System (INIS)

    Genetic analysis of resistance to the inhibitory effects of UV radiation on growth of rice (Oryza sativa L.) cultivars was carried out. Some experimental plants were grown in visible radiation supplemented with UV radiation containing a large amount of UV-B and a small amount of UV-C in a phytotron, while others were grown without UV radiation. The degree of resistance to UV radiation was estimated in terms of the degree of reduction caused by supplemental UV radiation in the fresh weight of the aboveground plant parts and the chlorophyll content per unit fresh weight. Fresh weight and chlorophyll content in F2 plants generated by reciprocally crossing cv. Sasanishiki, a cultivar more resistant to UV radiation, and Norin 1, a cultivar less resistant to such radiation exhibited a normal frequency distribution. The heritabilities of these two properties in F2 plants were low under conditions of non-supplemental UV radiation. Under elevated UV radiation, the F2 population shifted to the lower range of fresh weight and chlorophyll content, and the means were close to those of Norin 1. The heritabilities of these two properties were the same in the reciprocal crosses, indicating that maternal inheritance was not involved. Inheritance of chlorophyll content per unit fresh weight was further determined in F3 lines generated by self-fertilizing F2 plants of Sasanishiki and Norin 1. The results showed that the F3 population was segregated into three genotypes, namely, resistant homozygotes, segregated heterozygotes and sensitive homozygotes, with a ratio of 1:65:16. It was thus evident that the resistance to the inhibitory effect of elevated UV radiation in these rice plants was controlled by recessive polygenes. (author)

  6. 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.

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

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Effect of UV- B radiation on the feeding behavior of the rotifer Brachionus plicatilis

    Institute of Scientific and Technical Information of China (English)

    FENG Lei; LI Xin; WANG Jinhe; HAN Honglei; TANG Xuexi; CHEN Xiguang

    2007-01-01

    Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. ,Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively (P < 0.05 ) which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, I.galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment (2.70 kJ/m2) , the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, I. galbana and T. chuii in turn.Chlorella sp. , I. galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.

  10. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    OpenAIRE

    Garcia-Corral, Lara S.; Martinez-Ayala, Juan; Duarte, Carlos M.; Agusti, Susana

    2015-01-01

    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 ...

  11. Biologically weighted measurement of UV radiation in space and on earth with the biofilm technique

    Science.gov (United States)

    Rettberg, P.; Horneck, G.

    Biological dosimetry has provided experimental proof of the high sensitivity of the biologically effective UVB doses to changes in atmospheric ozone and has thereby confirmed the predictions from model calculations. The biological UV dosimeter 'biofilm' whose sensitivity is based on dried spores of B. subtilis as UV target weights the incident UV radiation according to its DNA damaging potential. Biofilm dosimetry was applicated in space experiments as well as in use in remote areas on Earth. Examples are long-term UV measurements in Antarctica, measurements of diurnal UV profiles parallel in time at different locations in Europe, continuous UV measurements in the frame of the German UV measurement network and personal UV dosimetry. In space biofilms were used to determine the biological efficiency of the extraterrestrial solar UV, to simulate the effects of decreasing ozone concentrations and to determine the interaction of UVB and vitamin D production of cosmonauts in the MIR station.

  12. Short term exposure of UV-V radiation enhances salinity tolerance in vigna radiata

    International Nuclear Information System (INIS)

    Electromagnetic radiation (7%) emitted from the sun is in the UV range (200-400) nm. Several morphological and anatomical changes have been reported from plants grown under long-term UV-B regimes. The effect of UV-B radiation (280-320 nm) and salinity alone and in combination were studied. Fifteen days old seedlings of Vigna radiata were exposed to UV-B radiation for 10, 20 and 30 minutes and salinity treatment was given to the plants 3 days before the UV-B treatment. UV radiation was artificially provided by Esco Airstream Vertical Laminar Flow Cabinet (AVC-4AI). Significant decrease (p<0.05) in root and shoot length, specific leaf area, chlorophyll and carotenoid content of in all UV-B and salinity treatments was observed as compared to control. The reduction was more pronounced in salinity treatment as compared to UV-B alone and combination of UV-B with salinity. It is concluded that the short term exposure of UV-B radiation enhances the salinity tolerance in Vigna radiata. (author)

  13. Direct effects of elevated UV-B radiation on the decomposition of Quercus robur leaf litter

    International Nuclear Information System (INIS)

    Decomposing Quercus robur L. leaf litter was exposed for 64 weeks at an outdoor facility to supplemental levels of UV-B radiation (280-315 nm) under treatment arrays of cellulose diacetate-filtered fluorescent lamps which also produce UV-A radiation (315-400 nm). Litter was also exposed to UV-A radiation alone under control arrays of polyester-filtered lamps and to ambient levels of solar radiation under arrays of unenergised lamps. The treatment corresponded to a 30% elevation above the ambient erythemally-weighted level of UV-B radiation. Litter was sampled after 11, 39 and 64 weeks and was examined for differences in mass loss, decomposition constants (k), chemical composition and the abundances of saprotrophic fungi. No effects of UV radiation on k values were recorded, but after 11 weeks, percentage mass loss of litter exposed to UV-B radiation under treatment arrays was 3% lower than under control arrays and 2% lower than under ambient arrays. After 39 weeks, litters exposed to UV-A radiation under control arrays had 10% lower total nitrogen contents and 13% higher C:N ratios than those litters exposed beneath ambient arrays. At the last sampling, litters exposed to supplemental UV-B radiation had 5% higher carbon contents than those under ambient arrays. A 2.4-fold increase in the frequency of lamina particles of litter that were uncolonised by fungi was recorded in litter exposed to UV-B radiation under treatment arrays, compared to ambient arrays. The abundances of the saprotrophic fungi Cladosporium spp. and Acremonium persicinum (Nicot) W. Gams were decreased by 50% and 91%, respectively, under UV-B treatment arrays compared to ambient arrays, and the abundance of coelomycete conidiomata recorded on leaves was increased by 12% under treatment arrays, compared to ambient. Dactylella spp. were not recorded on litter exposed to UV-A radiation under control arrays and UV-A radiation applied under control and treatment arrays apparently increased the

  14. 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

  15. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  16. Effect of UV-B radiation on leaf optical properties measured with fibre optics

    International Nuclear Information System (INIS)

    Changes in the internal light microenvironment in leaves of plants of Brassica campestris L. cv. Emma, B. carinata L., and Medicago saliva L. cv. Armour in response to exposure to UV-B (UV-B, 280–320 nm) radiation were measured using a fibreoptic microprobe. Plants were exposed for 2 weeks either to high visible light or to supplemental ultraviolet-B radiation. The spectral regime (400–700 nm; PAR ) was measured either midway through the leaf palisade or the spongy mesophyll. After exposure to UV-B radiation leaves of Brassica campesiris attenuated transmitted light more than the controls. At the same time both forward and back scattered light increased in the palisade and spongy mesophylls. In contrast, UV-treatment of Medicago saliva leaves increased light transmission into the palisade, while the back scattered component showed little change. Leaves of cariiwla showed little change in response to UV. Other responses to UV-B radiation included increases in leaf thickness, decreased total chlorophyll content, and changes in UV-B screening pigments and chlorophyll fluorescence induction kinetics. Brassica campestris was most sensitive to exposure to enhanced levels of UV-B radiation, whereas leaves of B. carinata were the least sensitive. Our data indicate that exposure to UV-B radiation altered the light microenvironment within leaves of the species different ways. These changes appeared to be caused by alterations in pigment content and leaf anatomy. In turn, the altered distribution of PAR within the leaf could influence photosynthesis

  17. Effects of UV-B Radiation and Water Stress on Soybean Yield

    Institute of Scientific and Technical Information of China (English)

    REN Hongyu; XU Haiming; LI Dongming; HUANG Rui; WANG Licheng

    2009-01-01

    Soybean Dongnong 47 was subjected to the experiments of increasing UV-B radiation and water stress on soybean yield components in different growth periods. The results showed that 100-seed weight greatly increased during the early stage of pod filling in the treatment of weak UV-B radiation, seed number per plant as well as seed weight per plant and Dongnong47 yield also increased, while the yield and yield components of Dongnong47 during the blossom to mature period were negatively affected in the treatment of intensive UV-B radiation. 100-seed weight of Dongnong47 all increased in the double factor treatments of UV-B radiation and water stress, with the drought intensified, seed number per plant, seed weight per plant and yield of Dongnong47 decreased, the change of 100-seed weight were various and the antagonistic action of UV-B radiation and water stress were related with their intensity.

  18. Short-term responses of barley to changes in ambient levels of UV-B radiation and their role in UV protection

    Science.gov (United States)

    Sullivan, Joseph H.; Gitz, Dennis C.; Stapleton, Ann E.; Gao, Wei; Slusser, James R.

    2003-06-01

    While many studies have evaluated the chronic effects of exposure to enhanced levels of UV-B radiation on plants very few studies have evaluated the implications of plant development within a background of fluctuating levels of UV-B radiation. Much interest and concern surround the issue of stratospheric ozone depletion and concurrent increases in UV-B radiation and this remains a concern. However, variation in UV-B levels on a daily basis is largely due to cloud cover and tropospheric air quality as well as possible effects of fluctuations in the total ozone column. Therefore the importance of the effects of short-term changes in UV-B radiation is not predicated on the assumption of continued ozone destruction. In this study we evaluated to change in foliar phenolic composition in barley and the consequences of changes in these putative protection compounds on subsequent sensitivity to UV-V radiation. The UV-B exposure levels ranges from less than 1 to nearly 8 kJ m-2 of biologically weighted UV-B radiation. Barley plants that developed under height ambient levels of UV-B radiation had higher levels of phenolics than control plants grown under the same conditions except with UV-B excluded. Those plants with higher phenolic content show some degree of increased protection from subsequent levels of UV-B as evidenced by less damage to DNA. However, it was also found that other environmental factors contributed to the induction of foliar screening compounds.

  19. Physiological sensitivity of plants along an elevational gradient to UV-B radiation

    International Nuclear Information System (INIS)

    Seeds from four plant pairs collected from contrasting elevations in Hawaii were grown in greenhouses at the University of Maryland at UV-B radiation levels that approximated a 20% and 40% stratospheric ozone depletion anticipated at sea level in Maui. In general, increases in UV-B radiation resulted in earlier reproductive effort, increased dark respiration and maintenance of relative water content (RWC), photosynthesis, and apparent quantum efficiency (AQE) in plants from higher elevations where natural UV-B radiation is already high. In contrast, plants collected from low elevational ranges showed a significant decline in average plant and floral dry biomass, a decline in AQE and RWC, and a reduction in light-saturated photosynthetic capacity. Increases in UV-B-absorbing compounds (e.g., flavonoids), were noted for low elevation but not high elevation plants. However, plants from high elevations produced a consistently larger amount of these compounds even in the absence of UV-B radiation. This study suggests that plants growing in a naturally high UV-B environment may have developed or maintained mechanisms related to reproductive phenology and carbon uptake which may maintain productivity in a high UV-B environment. This would also suggest that ecotypic differentiation may have occurred in response to increasing UV-B radiation over an elevational gradient. The range of adaptability to increased UV-B also implies changes in species and community dynamics that might be anticipated in natural plant populations if stratospheric ozone depletion continues

  20. Physiological and ultralstructural changes of Chlorella sp. induced by UV-B radiation

    Institute of Scientific and Technical Information of China (English)

    YU Juan; TANG Xuexi; ZHANG Peiyu; TIAN Jiyuan; DONG Shuanglin

    2005-01-01

    In order to investigate the mechanisms of enhanced UV-B radiation on algae, the effects of UV-B radiation on the physiological and ultrastructural changes of Chlorella sp. were examined. The results showed that UV-B radiation could inhibit the growth and photosynthesis of microalgae. UV-B radiation at lower doses increased the photosynthetic pigment (chlorophyll a (Chla) and carotenoid (Car)) contents, while at higher doses of UV-B radiation Chla and Car contents were decreased. The ultrastructure of Chlorella sp.without exposure to UV-B showed that the thylakoidlamellae were clear and regular, the stroma of its chloroplast was apparent and clear.The globules with photosynthetic pigments and the cristae of mitochondria were clearly seen. After exposure to UV-B radiation at dose of 2.88 kJ/m2, the thylakoid lamellae of Chlorella sp. were lost and dissolved, the globules which contained photosynthetic pigments in chloroplast were bleached; some mitochondria cristae were dissolved; slight plasmolysis was found in some Chlorella sp. cells. After exposure to 5.76 kJ/m2 UV-B radiation, the thylakoid was in disarray and disintegration, plasmolysis was found in most cells, and the cell wall was broken and began to fall out. Many blank areas were observed in cells, mitochondria were seriously deformed and most of the mitochondria cristae were dissolved. Also, globules containing photosynthetic pigments in chloroplast were bleached and some empty globules were found in chloroplast. Therefore, UV-B radiation could damage cell structure of Chlorella sp., and this damage increased with the dose of UV-B radiation they exposed to.

  1. Effects of long-wavelength ultraviolet (UV-A) radiation on the growth of Anacystis Nidulans

    International Nuclear Information System (INIS)

    The growth of Anacystis nidulans cells which had been grown under visible light only (>390 nm) was suppressed by long-wavelength ultraviolet (UV-A, 320-390 nm) radiation. The growth resumed after 24 h. Cells grown under UV-A supplemented light contained less chlorophyll and phycocyanin and more carotenoid than control cells. The finding that UV-A radiation inhibited the rate of delta-aminolevulinic acid synthesis indicated that the decreases in the photosynthetic pigments were mainly due to the inhibition of their biosynthesis rather than to photodestruction of pigments by UV-A radiation. The primary cause of the inhibitory effects seems to be the inhibition of the photosynthetic process which can be measured as the rho-benzoquinone Hill reaction. Previous exposure to UV-A radiation conferred some resistance on the cells to this inhibitory radiation. Thus UV-A radiation itself may activate a system that repairs damage caused by UV-A radiation and/or protects against the radiation. (author)

  2. The legal situation of the radiation protection agent

    International Nuclear Information System (INIS)

    The radiation protection agent is an entirely office-internal institution and no public-legal control instance. Its task solely consists of supporting the person responsible for radiation protection in fulfilling his/her duties concerning radiation protection thus enabling him/her to do his/her public-legal duties. Adherence to these duties is controlled by the authority without regard to the person responsible for radiation protection (paragraph 32). The radiation protection agent only acts on private level in reaction to the person responsible for radiation protection. Interpretation of the concrete legal relationships depends on the point if the radiation protection agent acts as internal or external expert. In the first case, the relationship is based on a work contract, i.e. any legal arguing must be carried out at employment courts. There is no special protection for the radiation protection agent concerning his time of notice. In the case of an external radiation protection agent, the mutual duties are legally based on the work or employment contract which was signed on the basis of civil law. Arguments are subject to orderly courts. (orig./HP)

  3. 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 with......, 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 of...... 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....

  4. 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.

  5. Effects of Elevated Solar UV-B Radiation from Ozone Depletion on Terrestrial Ecosystems

    Institute of Scientific and Technical Information of China (English)

    LIU Qing; Terry V. Callaghan; ZUO Yuanyuan

    2004-01-01

    In the last three decades much research has been carried out to investigate the biological effects of a thinning stratospheric ozone layer accompanied by an enhanced level of solar ultraviolet-B radiation at the Earth's surface. Enhanced UV-B radiation affects ecosystems in many ways directly and indirectly. The responses can be biochemical, physiological, morphological or anatomical, and the direction of the response can vary between different species, communities and ecosystems. In this paper we firstly introduce general concepts, and methods for measuring the ecological effects of UV-B radiation. Secondly, we provide an overview interpretation of the effects of enhanced UV-B on terrestrial ecosystems from recent studies. These studies include effects of UV-B on growth and reproduction, composition of communities, competitive balance, decomposition of litter, and interactions with other factors etc. Finally, we recommend future research directions to identify the effects of elevated UV-B radiation on ecosystems in China.

  6. Antarctic network of lamp-calibrated multichannel radiometers for continuous ozone and uv radiation data

    OpenAIRE

    Redondas, A.; Torres, C.; O. Meinander; K. Lakkala; R. García; E. Cuevas; Ochoa, H.; Deferrari, G.; Díaz, S.

    2008-01-01

    Three NILU-UV multichannel radiometers have been installed in 1999 at the Argentinian sites of Ushuaia (54S), Marambio (64S) and Belgrano-II (77S) in order to continuously monitor UV radiation, photosynthetically active radiation and total ozone. The measurements were established by INM, Spain in collaboration with FMI, Finland, DNA-IAA, Argentina and CADIC, Argentina to observe and characterize the spatial and temporal evolution of ozone and ultraviolet radiation in the Antarctic region. Spe...

  7. Control of development in plants and fungi by far-UV radiation

    International Nuclear Information System (INIS)

    Far-UV (200–320 nm) radiation regulates development in plants and fungi. Some of these responses are controlled by a chromophore which absorbs strongly near 260 nm, possibly a nucleic acid. Other responses are controlled by a chromophore(s). with maximal in vivo sensitivity near 295 nm. In plants. far-UV induces genes in the phenylpropanoid pathway and the synthesis of phytoalexins and flavonoids. Far-UV also regulates growth rate. controls curvature and taxis, and stimulates sexual and asexual morphogenesis of fungi. Some of these developmental responses may prevent damage by far-UV radiation

  8. Antioxidant responses of damiana (Turnera diffusa Willd to exposure to artificial ultraviolet (UV radiation in an in vitro model: part II; UV-B radiation

    Directory of Open Access Journals (Sweden)

    Lluvia de Abril Alexandra Soriano-Melgar

    2014-05-01

    Full Text Available Introduction: Ultraviolet type B (UV-B radiation effects on medicinal plants have been recently investigated in the context of climate change, but the modifications generated by UV-B radiation might be used to increase the content of antioxidants, including phenolic compounds. Objective: To generate information on the effect of exposure to artificial UV-B radiation at different high-doses in the antioxidant content of damiana plants in an in vitro model. Methods: Damiana plantlets (tissue cultures in Murashige-Skoog medium were irradiated with artificial UV-B at 3 different doses (1 0.5 ± 0.1 mW cm-2 (high for 2 h daily, (2 1 ± 0,1 mW cm-2 (severe for 2 h daily, or (3 1 ± 0.1 mW cm-2 for 4 h daily during 3 weeks. The concentration of photosynthetic pigments (chlorophylls a and b, carotenoids, vitamins (C and E and total phenolic compounds, the enzymatic activity of superoxide dismutase (SOD, EC 1.15.1.1 and total peroxidases (POX, EC 1.11.1, as well as total antioxidant capacity and lipid peroxidation levels were quantified to assess the effect of high artificial UV-B radiation in the antioxidant content of in vitro damiana plants. Results: Severe and high doses of artificial UV-B radiation modified the antioxidant content by increasing the content of vitamin C and decreased the phenolic compound content, as well as modified the oxidative damage of damiana plants in an in vitro model. Conclusion: UV-B radiation modified the antioxidant content in damiana plants in an in vitro model, depending on the intensity and duration of the exposure.

  9. Potential application of UV radiation processing in electronic packaging

    International Nuclear Information System (INIS)

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

  10. Differential regulation of caspase-9 by ionizing radiation- and UV-induced apoptotic pathways in thymic cells

    International Nuclear Information System (INIS)

    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. Effects of different levels of vitamin C on UV radiation-induced DNA damage

    Institute of Scientific and Technical Information of China (English)

    Dianfeng Zhou; Hang Heng; Kang Ji; Weizhong Ke

    2005-01-01

    The Raman spectra of DNA in different levels of vitamin C with 10- and 30-min ultraviolet (UV) radiations were reported. The intensity of UV radiation was 18.68 W/m2. The experimental results proved that vitamin C could alone prevent UV radiation from damaging DNA, but the effects depended on the concentration of vitamin C. When the concentration of vitamin C was about 0.08-0.4 mmol/L, vitamin C decreased UV radiation-induced DNA's damage. When the concentration of vitamin C exceeded 0.4 mmol/L, vitamin C accelerated DNA's damage instead. Maybe the reason is that when DNA in aqueous solution is radiated by UV, free radicals come into being, and vitamin C can scavenge free radicals, so vitamin C in lower concentration can protect DNA. The quantity of free radicals is finite, when vitamin C is superfluous, free radicals have been scavenged absolutely and vitamin C is residual. Vitamin C is a strong reductant. When the mixture of DNA and residual vitamin C is radiated by UV, vitamin C reacts with DNA. The more residual vitamin C and the longer time of UV radiation, the more DNA is damaged.

  12. Response of Marine Microalgae, Heterotrophic Bacteria and Their Relationship to Enhanced UV-B Radiation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wenli; TANG Xuexi; XIAO Hui; WANG You; WANG Renjun

    2009-01-01

    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 pho-tosynthesis rate; this rachation 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 nucroalgal 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 microal-gae and heterotrophic bacteria and the interaction between them.

  13. 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.

  14. Preconditioning under high par of exposure to UV-A radiation both allow acclimation of the photosynthetic apparatus of barley transferred to UV-B radiation

    Czech Academy of Sciences Publication Activity Database

    Štroch, Michal; Materová, Z.; Vrábl, D.; Šigut, Ladislav; Špunda, Vladimír

    Brno : Global change research centre, Academy of Sciences of the Czech Republic, v. v. i, 2013 - (Stojanov, R.; Žalud, Z.; Cudlín, P.; Farda, A.; Urban, O.; Trnka, M.), s. 248-251 ISBN 978-80-904351-8-6. [Global Change and Resilience. Brno (CZ), 22.05.2013-24.05.2013] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA ČR GA522/09/0468 Institutional support: RVO:67179843 Keywords : barley * clorophyll fluorescence * light acclimation * photosynthesis * photosynthetic pigments * UV screening * UV-A and UV-B-radiation Subject RIV: EH - Ecology, Behaviour

  15. 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.

  16. 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.

  17. Surface modification of the polyethyleneimine layer on silicone oxide film via UV radiation

    International Nuclear Information System (INIS)

    We herein report a novel method of employing 254 nm of UV radiation (UV) for the modification of a polyethyleneimine (PEI) layer on silicone oxide film. In this study, a PEI layer composed of a 50 mM sodium carbonate solution (pH 8.2) was formed on the surface of a silicone oxide film with spontaneous adsorption. Then, thin film of PEI was patterned by UV radiation. To determine the effect of the UV radiation, fluorescence microscopy, X-ray electron spectroscopy (XPS), and Fourier Transform Infrared spectroscopy (FT-IR) analyses were performed. These results indicated that UV radiation could cause changes in the surface characteristics of the PEI layer. Subsequently, FT-IR analysis showed changes in the chemical composition of the PEI exposed to UV radiation, such as the disappearance of the amine. Based on these results, we can conclude that UV radiation could be used to eliminate the amine group selectively and that this technique could be applied to create a pattern on the surface of a PEI layer.

  18. 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.

  19. Cutaneous vitamin D synthesis versus skin cancer development: The Janus faces of solar UV-radiation

    OpenAIRE

    Reichrath, Jörg; Nürnberg, Bernd

    2009-01-01

    In scientific and public communities, there is an ongoing discussion how to balance between positive and negative effects of solar UV-exposure. On the one hand, solar UV-radiation represents the most important environmental risk factor for the development of non-melanoma skin cancer. Consequently, UV protection is an important measure to prevent these malignancies, especially in risk groups. Otherwise, approximately 90% of all vitamin D needed by the human body has to be formed in the skin th...

  20. 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.

  1. 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 with......, 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 of...... electron transport (Jmax) and the maximum carboxylation rate of Rubisco (Vcmax), and the PSII performance showed a decreased quantum yield and increased energy dissipation. A parallel response pattern and reduced PSII performance at all three sites indicate that these responses take place in all leaves...

  2. DNA radiation damage and asymmetric somatic hybridization: Is UV a potential substitute or supplement to ionising radiation in fusion experiments?

    International Nuclear Information System (INIS)

    Recent reports have revealed that the asymmetric nature of the nuclear genome of somatic hybrids, produced following the irradiation of one of the parents with X- or gamma rays, is generally much less than had been anticipated. As a consequence, we have begun to investigate whether UV radiation might be used as an alternative or indeed a supplement to the presently-used ionising radiation techniques in such experiments. Cell culture studies have revealed that UV radiation induces the desired physiological effects in sugar beet (Beta vulgaris) protoplasts, namely, a prevention of cell division without immediate cytotoxicity. Preliminary studies using denaturing and pulsed field gel electrophoresis have shown that UV can also induce substantial physical fragmentation of DNA. When using the same techniques, less breakdown was observed following gamma radiation. All results were highly reproducible. Such results augur well for the potential use of UV in asymmetric somatic cell fusion experiments. (author)

  3. The effect of UV-B and UV-C radiation on Hibiscus leaves determined by ultraweak luminescence and fluorescence induction [chlorophyll fluorescence induction, ultraweak luminescence

    International Nuclear Information System (INIS)

    The effects of UV-C (254 nm) and UV-B (280-320 nm) on chlorophyll fluorescence induction and ultraweak luminescence (UL) in detached leaves of Hibiscus rosa-sinensis L. were investigated. UL from leaves exposed to UV-B and UV-C radiation reached a maximum 72 h after irradiation. In both cases most of the light was of a wavelength over 600 nm. An increase in the percentage of long wavelength light with time was detected. UV radiation increased peroxidase activity, which also reached a maximum 72 h after irradiation. UV-B and UV-C both reduced variable chlorophyll fluorescence. No effect on the amount of chlorophyll or UV screening pigments was observed with the short-term irradiation used in this investigation. (author)

  4. 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.

  5. 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...

  6. Influence of Seed pre-treatment by UV-A and UV-C radiation on germination and growth of Mung beans

    Directory of Open Access Journals (Sweden)

    *N. Hamid

    2011-12-01

    Full Text Available The consequence of pre-treatment of UV-A (366 nm and UV-C (254 nm radiation on seed germination and growth of Vigna radiata was investigated at three different exposure period (2, 4 and 6 hours. Supplementation of UV-A enhanced the germination rate, specific leaf area, root and shoot length and dry weight than the UV-C supplemented plants.

  7. 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...... the ozone layer) with artificially increased precipitation. The Swedish experiment also involved a study of the interaction between enhanced UV-B radiation and elevated CO2 (600 ppm). These field studies were supported by an outdoor controlled environment study in the United Kingdom involving...... modulated enhancement of UV-B radiation in combination with elevated CO2 (700 ppm). Effects of the treatments on plant growth, morphology, phenology and physiology were measured. The effects observed were species specific, and included both positive and negative responses to the treatments. In general the...

  8. Evaluation of UV-permeability and photo-oxidisability of organic ultraviolet radiation-absorbing coatings

    International Nuclear Information System (INIS)

    Highlights: • We investigate organic UV radiation-absorbing coatings for use on bamboo surfaces. • The size of glass exactly inserted into sample cell of UV-Vis spectrophotometer. • A model was made to predict UV absorption of coatings. • We examine carbonyl groups change of coatings after ageing. • Two formulations which could effectively protect coating were obtained. - Abstract: Enhancing the durability of the coatings used on bamboo products is essential for increasing their use in outdoor environments. In this study, we investigated organic UV radiation-absorbing coatings for use on bamboo surfaces. The degree of resistance of the coatings, which contained 2-(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chlorinated benzotriazole (BTZ-1), to UV radiation degradation was determined through spectroscopic analysis. The critical BTZ-1 loading amount was determined by analysing the spectroscopic data. Fourier transform infrared spectroscopy was used to elucidate the relationship between the degree of photooxidation of the coatings and their BTZ-1 concentration. The experimental results showed that the coatings provided a high degree of shielding from UV radiation. The critical loading amount was determined to be 1.82 ± 0.05 g BTZ-1/m2. The coatings formed using the formulations that contained 3 and 5 wt% BTZ-1 exhibited the lowest degree of photooxidation after exposure to UV radiation

  9. Evaluation of UV-permeability and photo-oxidisability of organic ultraviolet radiation-absorbing coatings

    Energy Technology Data Exchange (ETDEWEB)

    Li, Neng; Chen, Yuhe, E-mail: yuhec@sina.com; Bao, Yongjie; Zhang, Zeqian; Wu, Zaixing; Chen, Zhangmin

    2015-03-30

    Highlights: • We investigate organic UV radiation-absorbing coatings for use on bamboo surfaces. • The size of glass exactly inserted into sample cell of UV-Vis spectrophotometer. • A model was made to predict UV absorption of coatings. • We examine carbonyl groups change of coatings after ageing. • Two formulations which could effectively protect coating were obtained. - Abstract: Enhancing the durability of the coatings used on bamboo products is essential for increasing their use in outdoor environments. In this study, we investigated organic UV radiation-absorbing coatings for use on bamboo surfaces. The degree of resistance of the coatings, which contained 2-(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chlorinated benzotriazole (BTZ-1), to UV radiation degradation was determined through spectroscopic analysis. The critical BTZ-1 loading amount was determined by analysing the spectroscopic data. Fourier transform infrared spectroscopy was used to elucidate the relationship between the degree of photooxidation of the coatings and their BTZ-1 concentration. The experimental results showed that the coatings provided a high degree of shielding from UV radiation. The critical loading amount was determined to be 1.82 ± 0.05 g BTZ-1/m{sup 2}. The coatings formed using the formulations that contained 3 and 5 wt% BTZ-1 exhibited the lowest degree of photooxidation after exposure to UV radiation.

  10. Mutagenic interactions between near-ultraviolet (365 nm) radiation and alkylating agents in Escherichia coli

    International Nuclear Information System (INIS)

    The mutagenic interaction between near-ultrviolet (365 nm) radiation and the alkylting agents ehtyl methanesulponate (EMS) and methyl methanesulphonate (MMS) was studied in a repair-component and an excision-deficient stram of Escherichia coli. Near-UV raditation modified the metabolic response of of exposure to these chemicals and either reduced or increased their mutagenic efficiency. Based on these results, an experimental model was formulated to explain the mutagenic interactions that occur between near-UV and various agents that induce prototrophic reverants cia error-prone repair of DNA. According to this model, low doses of near-UV provoke conditions for mutation frequency decline (MFI) and lead to a mutagenic antagonism. With increasing near-Uv doses, damage to constitutive error-free repairs system increases, favouring the error-prone system and inhibiting the MFD. Under these conditions there will be a progressive decrease in antagonism until at high doses an enhancement of mutation frequency (positive interaction) will occur. (orig.)

  11. Oceanic protection of prebiotic organic compounds from UV radiation

    OpenAIRE

    Cleaves, H. James; Miller, Stanley L.

    1998-01-01

    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 molecul...

  12. Plasticity in pigmentation induced by conflicting threats from predation and UV radiation

    OpenAIRE

    Hansson, Lars-Anders

    2004-01-01

    In a variable and unpredictable environment, phenotypic plasticity in morphology or behavior may considerably improve an organism's protection against environmental threats and thereby its fitness. Here I demonstrate that common freshwater organisms, copepods (Crustacea), show a plastic response by adjusting pigmentation level in relation to two environmental threats: ultraviolet radiation (UV) and predation. The red pigment in copepods, astaxanthin, reduces damage caused by UV radiation,...

  13. Measurement of leaf epidermal transmittance of UV radiation by chlorophyll fluorescence

    International Nuclear Information System (INIS)

    In higher plants one of the important functions of the leaf epidermis is the effective screening of ultraviolet-B (280–320 nm, UV-B) radiation, due mostly to phenolic compounds. The assessment of the contribution of this function is necessary for an evaluation of the impact of increasing UV-B radiation. A method is proposed to estimate epidermal transmittance on the basis of chlorophyll fluorescence measurements. Fluorescence of chlorophyll induced by UV-A (320–400 nm, measuring beam centered at 366 nm, half band width 32 nm) or UV-B (measuring beam centered at 314 nm, half band width 18 nm) is compared to that induced by a blue-green measuring light (475 nm, half band width 140 nm). It is shown that the ratios of UV-and blue-green (BG)-induced fluorescence, F(UV-A)/F(BG) and F(UV-B)/F(BG), are relatively constant among leaf samples of various species (Vicia faba, Spinacia oleracea, Rumex scutatus) from which the epidermis was removed. In epidermis-free leaves no significant differences were found between adaxial and abaxial leaf sides, suggesting that leaf structure has negligible influence on the F(UV)/F(BG) ratios. On the other hand, fluorescence excitation ratios varied over a vast range when intact leaves from different species and habitats were investigated. Ratios were low in sun leaves and relatively high in shade- and greenhouse-grown leaves. By relating these results to those obtained with epidermis-free leaves, epidermal transmittances for UV-B radiation could be estimated, with values ranging between 1 and 45%. The data demonstrate a large adaptability of epidermal UV-A and UV-B transmittance in higher plants. The proposed method may prove a versatile and relatively simple tool for investigating epidermal UV transmittance complementing established methods. (author)

  14. 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.

  15. 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.

    by the profile deviate from the values mea- sured by 14C technique a decade ago? and b) do these values reflect photo adaptabil- ity or photoinhibition due to UV R in Antarctic waters. The Senior author wishes to express her thanks to the Head....1% 15% 9.2% 1-19 (10 ? 9.2%) Temperate 22% (15%) 7% 0.1% 2-16 (7 ? 9.2%) 10 the action spectrum or even examination photo-inhibition by UV B and photore? covery by UV A per se could give varied insight of the influence of UV radiation on column...

  16. Influence of UV-B radiation on polyamines, lipid peroxidation and membrane lipids in cucumber

    International Nuclear Information System (INIS)

    Sensitive (Poinsett) and insensitive (Ashley) cultivars of cucumber (Cucumis sativus) were grown for four weeks from planting in unshaded greenhouses at 0 or 12.2 kJ m−2 day−1 of biologically effective ultraviolet-B (UY-BBE) radiation. The latter irradiance corresponded to a decrease in stratospheric ozone of ca 20% for clear sky conditions at Beitsville, MD on 21 June. The diamine putrescine and the polyamine spermidine accumulated in cotyledon and leaf tissues in response to UV-B radiation in both cultivars, but levels were not correlated with sensitivity to UV-B. Lipid peroxidation, as quantified by measurement of malondialdehyde (MDA), was increased by UV-B exposure. Significant cultivar differences were observed, with increases in lipid peroxidation in both cotyledons and leaves being correlated with UV-B sensitivity. Determination of membrane lipid composition indicated slight decreases in the unsaturated/saturated fatty acid ratios as a result of UV-B exposure. In general, Poinsett had a lower unsaturated/saturated ratio of fatty acids than did Ashley. These results indicate that membrane lipids may be a target of UV-B damage and that differences in the UV-B susceptibility of these two cultivars may involve differences in lipid metabolism. Polyamine accumulation in response to UV-B radiation stress is consistent with similar responses to other environmental stressors. (author)

  17. 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

  18. 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.

  19. UV-radiation and skin cancer dose effect curves

    International Nuclear Information System (INIS)

    Norwegian skin cancer data were used in an attempt to arrive at the dose effect relationship for UV-carcinogenesis. The Norwegian population is relatively homogenous with regard to skin type and live in a country where the annual effective UV-dose varies by approximately 40 percent. Four different regions of the country, each with a broadness of 1o in latitude (approximately 111 km), were selected . The annual effective UV-doses for these regions were calculated assuming normal ozone conditions throughout the year. The incidence of malignant melanoma and non-melanoma skin cancer (mainly basal cell carcinoma) in these regions were considered and compared to the annual UV-doses. For both these types of cancer a quadratic dose effect curve seems to be valid. Depletions of the ozone layer results in larger UV-doses which in turn may yield more skin cancer. The dose effect curves suggest that the incidence rate will increase by an ''amplification factor'' of approximately 2

  20. Effects of UV radiation on the rice field cyanobacterium, Aulosira fertilissima

    International Nuclear Information System (INIS)

    The effects of UV radiation (5 W m−2) were studied in the cyanobacterium, Aulosira fertilissima. The organism was found to be sensitive to UV-B and, to a lesser extent, UV-A. Absorption spectra showed that the pigment content, particularly phycocyanin, severely decreased following UV exposures; the effect was more pronounced with UV-B than with UV-A. The organism was also very sensitive to solar radiation, and complete bleaching of the cells occurred following exposure of 2–3 hr. The absorption and fluorescence emission spectra of crude pigments after 3 hr of UV-B exposure (5 W m−2) decreased significantly, suggesting the loss of effective energy transfer from the accessory pigments to PS-II. SDS-PAGE analysis of the total protein profile of cells treated with UV-B showed a decrease in the protein content with increasing exposure time. Substantial decrease in the protein bands occurred after 3 hr of UV-B exposure (5 W m−2), particularly of those between 14.2 and 45 kDa. (author)

  1. Modification of plasma membrane electron transport in cultured rose cells by UV-C radiation and fungal elicitor

    International Nuclear Information System (INIS)

    Previous experiments have shown that treatments of suspension-cultured cells of Rosa damascena Mill. with UV radiation or with fungal elicitors stimulates the synthesis of H2O2 by the cells. To test the hypothesis that this synthesis involves reduction of O2 at the plasma membrane and to identify the mechanism of the reduction, we have determined the effects of UV and elicitor on redox reactions associated with the plasma membrane. Elicitor prepared from cell walls of Phytophthora sp. (14 μg solids/ml) inhibited the reduction of ferricyanide by intact cells by 98%; UV-C (primarily 254 nm, up to 19,500 J/m2) inhibited this reduction by 40%. Neither treatment inhibited the reduction of Fe(III)-EDTA by intact cells. Intact cells oxidized NADH in the absence of external oxidizing agent, and the rate of oxidation was increased by UV and elicitor. Cells that were poisoned with arsenite and CCCP catalyzed the reduction of Fe(III)-EDTA in the presence of external NADH, and this ability was slightly stimulated by UV and elicitor. UV irradiation (6,480 J/m2) of cells resulted in a 27% inhibition of the specific activity of NADH-ferricyanide oxidoreductase in plasma membrane isolated from those cells. Elicitor treatment of cells for at least 90 min resulted in a 50% inhibition of the enzyme's specific activity in isolated plasma membrane; this inhibition was reversed by addition of Triton-X100 in the assay mixture. The results suggest that UV and elicitor alter the flow of electrons in the plasma membrane, reversibly inhibiting NADH-cytochrome b reductase, the putative key enzyme in the pathway of ferricyanide reduction, and stimulating (or at least not inhibiting) the pathway of Fe(III)-EDTA reduction

  2. 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...

  3. Characterisation of SiC photo-detectors for solar UV radiation monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Borchi, E.; Macii, R. [Fondazione Osservatorio Ximeniano, Via Borgo San Lorenzo, 26-50123 Firenze (Italy); Bruzzi, M. [INFN Firenze and Dipartimento di Energetica, Via S. Marta 3-50139 Firenze (Italy); Scaringella, M., E-mail: Scaringella@fi.infn.it [INFN Firenze and Dipartimento di Energetica, Via S. Marta 3-50139 Firenze (Italy)

    2011-12-01

    Silicon carbide has a potential for solar UV radiation monitoring: extremely resistant to UV radiation damage, nearly-blind to visible and infrared radiation and less sensitive to temperature variations than standard radiometric systems. A radiometer composed by three SiC photodiodes has been designed, manufactured and tested under solar radiation. Two photodiodes are equipped with filters in the UVB (280-315 nm) and UVA (315-400 nm) ranges while a third is filtered to match the erythemal action spectrum. UVA, UVB components of the solar radiation as well as UV index (UVI) at the earth's surface have been determined in two site positions in Tuscany, Italy. Data as a function of day-light allowed us to evaluate total optical thickness for UVA and UVB: {tau}{sub UVA}=0.46 and {tau}{sub UVB}=1.8. UVI values measured during the year well compares with computed ones used for weather forecast procedures.

  4. UV-B radiation: a health risk in the Arctic?

    OpenAIRE

    Noonan, Frances P.; C. de Fabo, Edward

    1999-01-01

    Seasonal stratospheric ozone depletion in the Arctic has raised the question of whether the associated increases in ultraviolet-B (290-320 nm) constitute a significant health risk in Arctic populations. Increases in skin cancer in Europe and the USA from excess UV-B resulting from ozone depletion have been predicted. Skin cancer is, however, rare in Inuit populations. UV-B also causes a selective down regulation of the immune system which may be a natural regulatory mechanism evolved to preve...

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

    International Nuclear Information System (INIS)

    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 the ozone layer) with artificially increased precipitation. The Swedish experiment also involved a study of the interaction between enhanced UV-B radiation and elevated CO2 (600 ppm). These field studies were supported by an outdoor controlled environment study in the United Kingdom involving modulated enhancement of UV-B radiation in combination with elevated CO2 (700 ppm). Effects of the treatments on plant growth, morphology, phenology and physiology were measured. The effects observed were species specific, and included both positive and negative responses to the treatments. In general the negative responses to UV-B treatments of up to three growing seasons were small, but included reductions in shoot growth and premature leaf senescence. Positive responses included a marked increase in flowering in some species and a stimulation of some photosynthetic processes. UV-B treatment enhanced the drought tolerance of Pinus pinea and Pinus halepensis by increasing leaf cuticle thickness. In general, there were few interactions between the elevated CO2 and enhanced UV-B treatments. There was evidence to suggest that although the negative responses to the treatments were small, damage may be increasing with time in some long-lived woody perennials. There was also evidence in the third year of treatments for effects of UV-B on insect herbivory in Vaccinium species. The experiments point to the necessity for long-term field investigations to predict the likely ecological consequences of increasing UV-B radiation. (author)

  6. Changes in epicuticular flavonoids and photosynthetic pigments as a plant response to UV-B radiation

    International Nuclear Information System (INIS)

    Treatment of Gnaphalium vira-vira plants with UV-B radiation caused changes in plant growth and in plant chemistry. The leaf surface contained two O-methylated flavones, araneol and 7-O-methylaraneol. HPLC analysis showed that 20 days of UV-B radiation increased the synthesis of 7-O-methylaraneol at the expense of araneol. Spectrophotometric analysis of the photosynthetic pigments showed that UV-B radiation also increases the pigment content in treated plants. Another U V alteration is epidermal hair damage, as observed in SEM pictures of treated leaves. This combination of physiological and phytochemical effects may be interpreted as a plant response to UV-B stress

  7. Multiple functional UV devices based on III-Nitride quantum wells for biological warfare agent detection

    Science.gov (United States)

    Wang, Qin; Savage, Susan; Persson, Sirpa; Noharet, Bertrand; Junique, Stéphane; Andersson, Jan Y.; Liuolia, Vytautas; Marcinkevicius, Saulius

    2009-02-01

    We have demonstrated surface normal detecting/filtering/emitting multiple functional ultraviolet (UV) optoelectronic devices based on InGaN/GaN, InGaN/AlGaN and AlxGa1-xN/AlyGa1-yN multiple quantum well (MQW) structures with operation wavelengths ranging from 270 nm to 450 nm. Utilizing MQW structure as device active layer offers a flexibility to tune its long cut-off wavelength in a wide UV range from solar-blind to visible by adjusting the well width, well composition and barrier height. Similarly, its short cut-off wavelength can be adjusted by using a GaN or AlGaN block layer on a sapphire substrate when the device is illuminated from its backside, which further provides an optical filtering effect. When a current injects into the device under forward bias the device acts as an UV light emitter, whereas the device performs as a typical photodetector under reverse biases. With applying an alternating external bias the device might be used as electroabsorption modulator due to quantum confined Stark effect. In present work fabricated devices have been characterized by transmission/absorption spectra, photoresponsivity, electroluminescence, and photoluminescence measurements under various forward and reverse biases. The piezoelectric effect, alloy broadening and Stokes shift between the emission and absorption spectra in different InGaN- and AlGaN-based QW structures have been investigated and compared. Possibilities of monolithic or hybrid integration using such multiple functional devices for biological warfare agents sensing application have also be discussed.

  8. DNA repair and resistance to UV-B radiation in western spotted frogs

    Science.gov (United States)

    Blaustein, A.R.; Hays, J.B.; Hoffman, P.D.; Chivers, D.P.; Kiesecker, J.M.; Leonard, W.P.; Marco, A.; Olson, D.H.; Reaser, J.K.; Anthony, R.G.

    1999-01-01

    We assessed DNA repair and resistance to solar radiation in eggs of members of the western spotted frog complex (Rana pretiosa and R. luteiventris), species whose populations are suffering severe range reductions and declines. Specifically, we measured the activity of photoreactivating enzyme (photolyase) in oocytes of spotted frogs. In some species, photoreactivation is the most important mechanism for repair of UV-damaged DNA. Using field experiments, we also compared the hatching success of spotted frog embryos at natural oviposition sites at three elevations, where some embryos were subjected to ambient levels of UV-B radiation and others were shielded from UV-B radiation. Compared with other amphibians, photolyase activities in spotted frogs were relatively high. At all sites, hatching success was unaffected by UV-B. Our data support the interpretation that amphibian embryos with relatively high levels of photolyase are more resistant to UV-B radiation than those with lower levels of photolyase. At the embryonic stage, UV-B radiation does not presently seem to be contributing to the population declines of spotted frogs.

  9. Antarctic network of lamp-calibrated multichannel radiometers for continuous ozone and uv radiation data

    Science.gov (United States)

    Redondas, A.; Torres, C.; Meinander, O.; Lakkala, K.; García, R.; Cuevas, E.; Ochoa, H.; Deferrari, G.; Díaz, S.

    2008-02-01

    Three NILU-UV multichannel radiometers have been installed in 1999 at the Argentinian sites of Ushuaia (54S), Marambio (64S) and Belgrano-II (77S) in order to continuously monitor UV radiation, photosynthetically active radiation and total ozone. The measurements were established by INM, Spain in collaboration with FMI, Finland, DNA-IAA, Argentina and CADIC, Argentina to observe and characterize the spatial and temporal evolution of ozone and ultraviolet radiation in the Antarctic region. Special attention has been given to the quality control and quality assurance of the measurements under harsh climatological conditions. The ozone and UV time series of 2000-2006 were calibrated using a polynomial fit for lamp measurements performed every second week all year round. The gaps in these data are minimal, with almost no data missing, and the data products are available from http://www.polarvortex.org in near real time. The data products include the erythemally-weighted UV, UVB and UVA radiation, photosynthetically active radiation (PAR), total ozone (O3) and a cloud parameter (CLT). For UV data, dose rates as well as daily doses are available; from these the maximum measured UV indices (UVI), during 2000-2006, were 12.0, 9.7 and 8.1 at Ushuaia, Marambio and Belgrano-II, respectively.

  10. Antarctic network of lamp-calibrated multichannel radiometers for continuous ozone and uv radiation data

    Directory of Open Access Journals (Sweden)

    A. Redondas

    2008-02-01

    Full Text Available Three NILU-UV multichannel radiometers have been installed in 1999 at the Argentinian sites of Ushuaia (54S, Marambio (64S and Belgrano-II (77S in order to continuously monitor UV radiation, photosynthetically active radiation and total ozone. The measurements were established by INM, Spain in collaboration with FMI, Finland, DNA-IAA, Argentina and CADIC, Argentina to observe and characterize the spatial and temporal evolution of ozone and ultraviolet radiation in the Antarctic region. Special attention has been given to the quality control and quality assurance of the measurements under harsh climatological conditions. The ozone and UV time series of 2000–2006 were calibrated using a polynomial fit for lamp measurements performed every second week all year round. The gaps in these data are minimal, with almost no data missing, and the data products are available from http://www.polarvortex.org in near real time. The data products include the erythemally-weighted UV, UVB and UVA radiation, photosynthetically active radiation (PAR, total ozone (O3 and a cloud parameter (CLT. For UV data, dose rates as well as daily doses are available; from these the maximum measured UV indices (UVI, during 2000–2006, were 12.0, 9.7 and 8.1 at Ushuaia, Marambio and Belgrano-II, respectively.

  11. Susceptibility of pollen to UV-B radiation: an assay of 34 taxa

    International Nuclear Information System (INIS)

    Much of the ultraviolet-B radiation (UV-B) research on plants has concentrated on vegetative plant parts, and only a small fraction has dealt with the reproductive system. The present study analyzed pollen grains of 34 taxa germinated and grown under two levels of UV-B radiation (187 and 460 mW/m2) or no UV-B (control group). Visible radiation at 260 micromoles m-2s-1 was present in all treatments. Taxa included those with binucleate and trinucleate pollen types. We detected differences among species. A significant reduction in pollen germination occurred in only five species. Pollen tubes of 50% of the species showed significant reduction in length. Trinucleate pollen types were more likely to exhibit tube length reduction than the binucleate types. Proportionately more monocotyledonous species were sensitive to UV-B treatment than dicotyledonous species, and proportionately more wild species were sensitive than cultivated species and pollen collected from plants growing in the field were somewhat more sensitive than pollen collected from plants grown in the greenhouse. Species in which pollination occurred earlier in the season were more likely to be susceptible to UV-B radiation than those for which anthesis took place later in the season, suggesting a possible adaptation to UV-B radiation. (author)

  12. UV radiation and primary production in the Antarctic waters

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Krishnakumari, L.; Bhattathiri, P.M.A.; Chandramohan, D.

    at 683 nm), scalar irradiance (photosynthetically active radiation (PAR), computed primary production (pp), diffuse attenuation coefficient, and UVB (308 and 320 nm) and UVA (340 and 380 nm) radiation and ocean temperature all measured as a function...

  13. Training strategic community agents in health effects of ionizing radiation

    International Nuclear Information System (INIS)

    The main motivation for the development of training was the need to train agents (opinion makers) with proximity and credibility among the population, to clarify the most frequently asked questions in relation to ionizing radiation, the operation of nuclear power plants, emergency plans and about the possibility of there effects of radiation on the health of inhabitants in regions close to the central Nuclear Almirante Alvaro Alberto - CNAAA. The project has a target audience of 420 agents, 60 of them have already been trained in a pilot project . The results indicate that the topics of training were adequate and the agents have expanded their knowledge. On the other hand, the information passed on to communities by agents, recognized by this population as ' the most reliable people', is of greater credibility and likelihood of success in communicating important issues for the population living in the vicinity of the CNAAA. (author)

  14. 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. PMID:26990026

  15. Ocean acidification mediates photosynthetic response to UV radiation and temperature increase in the diatom Phaeodactylum tricornutum

    Directory of Open Access Journals (Sweden)

    E. W. Helbling

    2012-06-01

    Full Text Available Increasing atmospheric CO2 concentration is responsible for progressive ocean acidification, ocean warming as well as decreased thickness of upper mixing layer (UML, thus exposing phytoplankton cells not only to lower pH and higher temperatures but also to higher levels of solar UV radiation. In order to evaluate the combined effects of ocean acidification, UV radiation and temperature, we used the diatom Phaeodactylum tricornutum as a model organism and examined its physiological performance after grown under two CO2 concentrations (390 and 1000 µatm for more than 20 generations. Compared to the ambient CO2 level (390 µatm, growth at the elevated CO2 concentration increased non-photochemical quenching (NPQ of cells and partially counteracted the harm to PSII caused by UV-A and UV-B. Such an effect was less pronounced under increased temperature levels. As for photosynthetic carbon fixation, the rate increased with increasing temperature from 15 to 25 °C, regardless of their growth CO2 levels. In addition, UV-induced inhibition of photosynthesis was inversely correlated to temperature. The ratio of repair to UV-induced damage showed inverse relationship with increased NPQ, showing higher values under the ocean acidification condition against UV-B, reflecting that the increased pCO2 and lowered pH counteracted UV-B induced harm.

  16. 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.

  17. Sensitivity of mononuclear cells to UV radiation; effect on subsequent stimulation with phytohemagglutinin

    International Nuclear Information System (INIS)

    The ability of peripheral blood mononuclear cells to incorporate 3[H] thymidine into nuclear DNA following stimulation by phytohemagglutinin is reduced by prior exposure to UV radiation in vitro; the reduction is dose and wavelength dependent. The doses required to affect this function of mononuclear cells are higher than the doses required to reduce trypan blue dye exclusion, so that following exposure to radiation populations of cells that are unable to exclude trypan blue dye are still capable of responding to phytohemagglutinin. This finding indicates that trypan blue dye exclusion may not accurately reflect the viability of cells after exposure to UV radiation. (author)

  18. 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...

  19. 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.

  20. Study into the effects of UV-B radiation on small aquatic animals

    International Nuclear Information System (INIS)

    Small aquatic animals (daphinia, reef coral) have been tested for their UV light tolerance. The LD-50 is most probably dependent of the habitat: Animals living in shallow waters tolerate higher UV radiation doses than those living in deep water. Significant differences in tolerance are detectable only when UV-Birradiation (max. effects at 280 nm) is accompanied or followed by visible short-wave irradiation (max. effects: 410-460 nm). The report presents a comparison for orientation of the UV-B tolerance determined in a field study under the impact of global radiation with and without exclusion of the UV radiation, and of a laboratory study for which artifical UV-B sources have been used. Several types of crustaceans and reef corals have been studied in these experiments. The report then explains a comparative analysis of the shallow waters animal Daphnia pulex obtusa, and of the seawater animal Daphina galeata, both exposed to monochromatic radiation. (orig./KG) With 37 refs., 8 tabs., 17 figs

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

    International Nuclear Information System (INIS)

    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 × 10−3 and 7.0 × 10−3 mW/cm2 for ultraviolet A (UVA), 1.0 × 10−3 and 2.0 × 10−3 mW/cm2 for ultraviolet B (UVB) and 6.0 × 10−3 and 8.0 × 10−3 mW/cm2 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 photocopier. The manufactures should be ultimated

  2. 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

  3. Plant Responses to Increased UV-B Radiation: A Research Project

    Science.gov (United States)

    DAntoni, H. L.; Skiles, J. W.; Armstrong, R.; Coughlan, J.; Daleo, G.; Mayoral, A.; Lawless, James G. (Technical Monitor)

    1994-01-01

    Ozone decrease implies more ultraviolet-B (UV-B) radiation reaching the surface of the Earth. Increased UV-B radiation triggers responses by living organisms. Despite the large potential impacts on vegetation, little is known about UV-B effects on terrestrial ecosystems. Long-term ecological studies are needed to quantify the effects of increased UV radiation on terrestrial ecosystems, asses the risks, and produce reliable data for prediction. Screening pigments are part of one of the protective mechanism in plants. Higher concentrations of screening pigments in leaves may be interpreted as a response to increased UV radiation. If the screening effect is not sufficient, important molecules will be disturbed by incoming radiation. Thus, genetics, photosynthesis, growth, plant and leaf shape and size, and pollen grains may be affected. This will have an impact on ecosystem dynamics, structure and productivity. It is necessary to monitor selected terrestrial ecosystems to permit detection and interpretation of changes attributable to global climate change and depleted ozone shield. The objectives of this project are: (1) To identify and measure indicators of the effects of increased solar UV-B radiation on terrestrial plants; (2) to select indicators with the greatest responses to UV-B exposure; (3) to test, adapt or create ecosystem models that use the information gathered by this project for prediction and to enhance our understanding of the effects of increased UV-B radiation on terrestrial ecosystems. As a first step to achieve these objectives we propose a three-year study of forest and steppe vegetation on the North slope of the Brooks Range (within the Arctic circle, in Alaska), in the Saguaro National Monument (near Tucson, Arizona) and in the forests and steppes of Patagonia (Argentina). We selected (1) vegetation north of the Polar Circle because at 70N there is 8% risk of plant damage due to increased UV-B radiation; (2) the foothills of Catalina Mountains

  4. Effects of salicylic acid (SA), ultraviolet radiation (UV-B and UV-C) on trans-resveratrol inducement in the skin of harvested grape berries

    Institute of Scientific and Technical Information of China (English)

    Xiaodong LI; Xianbo ZHENG; Shutang YAN; Shaohua LI

    2008-01-01

    Effects of salicylic acid (SA), ultraviolet radiation (UV-B and UV-C) on the trans-resveratrol (Res) inducement of the skin of harvested grape berries were studied with three grape cultivars Takasuma, Tano Red and Carigane. Split plot design tests were adopted to compare the effects of UV-B and UV-C radiation on Res inducement of different cultivars. Results showed that tents in the skins of harvested berries for the three-selected cultivars. However, the effect of SA varied with the cultivars, and Res inducement by SA was more effective to Tano Red than Takasuma and Carigane. UV-B or UV-C irradiation significantly increased Res contents in grape skins and UV-C was more effective than UV-B. The effects of UV types and dosages on Res inducement depended upon cultivars. In the range of 0-3.6 kJ.m-2, the Res contents in the skins of the three grape cultivars were enhanced along with the increase of dosages of UV-B and UV-C.

  5. Rediscovering leaf optical properties: New insights into plant acclimation to solar UV radiation.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Ryel, Ronald J; Tobler, Mark A; Barkley, Anne E; Wargent, Jason J

    2015-08-01

    The accumulation of UV-absorbing compounds (flavonoids and other phenylpropanoid derivatives) and resultant decrease in the UV transmittance of the epidermis in leaves (TUV), is a primary protective mechanism against the potentially deleterious effects of UV radiation and is a critical component of the overall acclimation response of plants to changing UV environments. Traditional measurements of TUV were laborious, time-consuming and destructive or invasive, thus limiting their ability to efficiently make multiple measurements of the optical properties of plants in the field. The development of rapid, nondestructive optical methods of determining TUV has permitted the examination of UV optical properties of leaves with increased replication, on a finer time scale, and enabled repeated sampling of the same leaf over time. This technology has therefore allowed for studies examining acclimation responses to UV in plants in ways not previously possible. Here we provide a brief review of these earlier studies examining leaf UV optical properties and some of their important contributions, describe the principles by which the newer non-invasive measurements of epidermal UV transmittance are made, and highlight several case studies that reveal how this technique is providing new insights into this UV acclimation response in plants, which is far more plastic and dynamic than previously thought. PMID:25465528

  6. Heated water and UV-C radiation to post harvest control of Cryptosporiopsis perennans on apples

    International Nuclear Information System (INIS)

    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)

  7. Differences of UV-B radiation sensitivity of rice%水稻对UV-B辐射响应的敏感性差异

    Institute of Scientific and Technical Information of China (English)

    何永美; 湛方栋; 高召华; 祖艳群; 李元

    2012-01-01

    综述了UV-B辐射对水稻(Oryza sativa L.)的影响和水稻对UV-B辐射的抗性机制.UV-B辐射对水稻生长、叶片形态、生物量、产量、光合系统、病害等产生一定的影响.水稻对UV-B辐射的敏感性因子主要有CPD光解酶、UV-B吸收物质、抗氧化酶等.UV-B辐射使水稻叶片中产生了ROS,导致Rubisco酶降解,光合色素含量变化,抑制了光合作用,最终影响水稻籽粒形成和产量.水稻对UV-B辐射响应存在着品种差异,CPD光解酶编码基因的自然突变会引起水稻UV-B敏感性的差异,CPD光解酶活性是水稻对UV-B敏感性的关键因素.通过建立响应指数公式,对水稻UV-B响应敏感性的品种差异进行评估,存在品种差异的原因主要是基因、生长、生理、生育期和环境背景的差异.最后对UV-B辐射对水稻的影响、水稻对UV-B响应的差异及机理有待深入研究的方向进行了展望.%The effects and its resistance mechanisms of enhanced UV-B radiation on rice were summarized. Effect of enhance UV-B radiation on the growth, leaf shape, biomass, yield, photosynthesis system and disease of rice were reported. Cyclobutane pyrimidine dimer (CPD) photolyase, UV-B absorbing compound and antioxidant enzymes are the main factors indicated the sensitivity of rice to UV-B radiation. UV-B radiation induces reactive oxygen species (ROS) production, Rubisco enzyme decomposition, photosynthetic pigments content decrease and photosynthesis inhibition of rice leaves, and resulted in decrease in grain yield. There were species differences on rice response to UV-B radiation. Spontaneous mutation of gene encoding CPD photolyase would cause UV-B sensitivity differences in rice. CPD photolyase activity is the key factor influencing in rice sensitivity to UV-B radiation. Species differences of rice response to UV-B radiation could be assessed by the response index. The differences in species mainly are due to genes, growth, physiology, reproductive

  8. Ozone depletion and increased UV-B radiation: is there a real threat to photosynthesis?

    International Nuclear Information System (INIS)

    This critical review of recent literature questions earlier predictions that photosynthetic productivity of higher plants is vulnerable to increased ultraviolet-B (UV-B) radiation as a result of stratospheric ozone (O3) depletion. Direct UV-B-induced inhibition of photosynthetic competence is observed only at high UV-B irradiances and primarily involves the loss of soluble Calvin cycle enzymes and adaxial stomatal closure in amphistomatous plants. However, even under these extreme UV-B exposures, acclimation (e.g. induction of UV-B absorbing flavonoids) can protect the photosynthetic processes. In plants irradiated with UV-B throughout development a reduction in productivity is usually associated with a reduced ability to intercept light (i.e. smaller leaf area) and not an inhibition of photosynthetic competence. Finally, a review of field experiments utilizing realistic UV-B enhancement is made to evaluate whether the mechanisms involved in UV-B-induced depressions of photosynthesis are likely to impact on the photosynthetic productivity of crops and natural vegetation in the future. Predictions of plant responses to O3 depletion are suspect from squarewave irradiance experiments in the field and controlled environments due to the increased sensitivity of plants to UV-B at relatively low photosynthetically-active photon flux densities (PPFD) and ultraviolet-A (UV-A) irradiances. Realistic modulated UV-B irradiances in the field do not appear to have any significant effects on photosynthetic competence or light-interception. It is concluded that O3 depletion and the concurrent rise in UV-B irradiance is not a direct threat to photosynthetic productivity of crops and natural vegetation. (author)

  9. Biological dosimeter for UV-radiation and alpha particles, based on DNA damages

    International Nuclear Information System (INIS)

    A bioluminescence method for determination of biologically relevant (DNA damaging) doses of UV-radiation and alpha particles is developed. The method is based on bacterial luminescence as a bio-marker regulated by the SOS system. Cultures of E. coli cells transformed with the plasmid pPSL1 which carries the lux gene under control of the col promotor, an SOS-controlling gene, is used. The lux gene encode the enzyme luciferase which takes part in the reaction, resulting in the emission of a visible light at 490 nm. The light output is measured by photomultiplier and one channel analyzer. SOS-response kinetic curves of bacteria, UV-irradiated and treated with alpha particles, are obtained. An assessment of the risk from solar UV-radiation is made. The method has the sensitivity required to be used as biological UV-dosimeter (author)

  10. Photosynthetic efficiency, and photodamage by UV and visible radiation, in red versus green leaf coleus varieties

    International Nuclear Information System (INIS)

    The maximum quantum yield for photosynthetic O2 evolution in red leaf coleus varieties having anthocyanin in their upper epidermis is much lower in green light and slightly lower in white light than in a green leaf variety lacking anthocyanin. A similar degree of photoinhibition occurred under excess visible light in the red versus green varieties; whereas, the red leaf varieties were less damaged by UV-B and UV-C radiation suggesting protection by anthocyanin in their epidermal tissue

  11. Photomorphogenic effects of UV-B radiation on plants: consequences for light competition

    International Nuclear Information System (INIS)

    A combination of field and labotatory studies were conducted to explore the nature of photomorphogenic effects of ultraviolet-B radiation (UV-B; 280–320 nm) on plant morphology and to evaluate the ecological consequences of these alterations in morphology for interspecific competition. Under laboratory conditions, seedlings of cucumber (Cucumis sativus L.) and tomato (Lycopersicon esculentum Mill.) exhibited appreciable (ca. 50%) and rapid (< 3h) inhibition in hypocotyl elongation in response to UV-B exposure. In cucumber, this inhibition was reversible, occurred without any associated changes in dry matter production and was caused by UV-B incident on the cotyledons and not the stem or growing tip. Inhibition of stem elongation in etiolated tomato seedlings occurred at least 3 h prior to the onset of accumulation of UV-absorbing pigments and monochromatic UV supplied against a background of visible radiation revealed maximum effectiveness in inhibition around 300 nm. Collectively, these findings suggest that a specific, but yet unidentified, UV-B photoreceptor is involved in mediating certain morphological responses to UV-B. For mixtures of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.), a common weedy competitor, supplemental UV-B irradiation in the field differentially altered shoot morphology which resulted in changes in canopy structure, light interception and calculated stand photosynthesis. It is argued that, because of its asymmetrical nature, competition for light can potentially amplify the effects of UV-B on shoot morphology and may, therefore, be an important mechanism by which changes in the solar UV-B spectrum associated with stratospheric ozone reduction could alter the composition and character of terrestrial vegetation

  12. The effect of UV-B radiation on chloroplast translation in Pisum sativum

    International Nuclear Information System (INIS)

    UV-B radiation has previously been reported to reduce growth, flowering, and net photosynthesis. The present study examines the effect of UV-B radiation on isolated chloroplast of 7-10 day old pea seedlings. Amount of (3H)-Leu incorporated into isolated chloroplasts was measured in the presence or absence of UV-B exposure. Preliminary experiments show a 30% inhibition of protein synthesis in isolated chloroplasts after only 20 mins of UV-B exposure (6.9 J/m2/30 min). Percent inhibition of chloroplast translation is directly correlated with UV-B exposure over a 60 min time span. Preliminary studies also show no change in both cold and radiolabeled protein profiles as expressed on 1-D PAGE and autofluorography. Comparative studies on the sensitivity of e- flow vs protein synthesis following UV-B exposure are underway. Further work on the role of oxygen free radicals and the specific site of action of UV-B damage to the translation machinery of chloroplasts will be discussed

  13. Action spectrum and mechanisms of UV radiation-induced injury in lupus erythematosus

    International Nuclear Information System (INIS)

    Photosensitivity associated with lupus erythematosus (LE) is well established. The photobiologic basis for this abnormal response to ultraviolet radiation, however, has not been determined. This paper summarizes the criteria for elucidating possible photobiologic mechanisms and reviews the literature relevant to the mechanism of photosensitivity in LE. In patients with LE, photosensitivity to wavelengths shorter than 320 nm has been demonstrated; wavelengths longer than 320 nm have not been adequately evaluated. DNA is a possible chromophore for photosensitivity below 320 nm. UV irradiation of skin produces thymine photodimers in DNA. UV-irradiated DNA is more antigenic than native DNA and the antigenicity of UV-irradiated DNA has been proposed, but not proven, to be involved in the development of clinical lesions. UV irradiation of mice previously injected with anti-UV-DNA antibodies produces Ig deposition and complement fixation that appears to be similar to the changes seen in lupus lesions. Antibodies to UV-irradiated DNA occur in the serum of LE patients although a correlation between antibody titers and photosensitivity was not observed. Defective repair of UV-induced DNA damage does not appear to be a mechanism for the photosensitivity in LE. Other mechanisms must also be considered. The chromophore for photosensitivity induced by wavelengths longer than 320 nm has not been investigated in vivo. In vitro studies indicate that 360-400 nm radiation activates a photosensitizing compound in the lymphocytes and serum of LE patients and causes chromosomal aberrations and cell death. The mechanism appears to involve superoxide anion

  14. Ocean acidification mediates photosynthetic response to UV radiation and temperature increase in the diatom Phaeodactylum tricornutum

    Directory of Open Access Journals (Sweden)

    E. W. Helbling

    2012-10-01

    Full Text Available Increasing atmospheric CO2 concentration is responsible for progressive ocean acidification, ocean warming as well as decreased thickness of upper mixing layer (UML, thus exposing phytoplankton cells not only to lower pH and higher temperatures but also to higher levels of solar UV radiation. In order to evaluate the combined effects of ocean acidification, UV radiation and temperature, we used the diatom Phaeodactylum tricornutum as a model organism and examined its physiological performance after grown under two CO2 concentrations (390 and 1000 μatm for more than 20 generations. Compared to the ambient CO2 level (390 μatm, growth at the elevated CO2 concentration increased non-photochemical quenching (NPQ of cells and partially counteracted the harm to PS II (photosystem II caused by UV-A and UV-B. Such an effect was less pronounced under increased temperature levels. The ratio of repair to UV-B induced damage decreased with increased NPQ, reflecting induction of NPQ when repair dropped behind the damage, and it was higher under the ocean acidification condition, showing that the increased pCO2 and lowered pH counteracted UV-B induced harm. As for photosynthetic carbon fixation rate which increased with increasing temperature from 15 to 25 °C, the elevated CO2 and temperature levels synergistically interacted to reduce the inhibition caused by UV-B and thus increase the carbon fixation.

  15. Effect of elevated CO2, O3, and UV radiation on soils.

    Science.gov (United States)

    Formánek, Pavel; Rejšek, Klement; Vranová, Valerie

    2014-01-01

    In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil N t content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research. PMID:24688424

  16. Effect of Elevated CO2, O3, and UV Radiation on Soils

    Directory of Open Access Journals (Sweden)

    Pavel Formánek

    2014-01-01

    Full Text Available In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil Nt content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research.

  17. The effects of enhanced UV-B radiation on a subarctic heath ecosystem

    International Nuclear Information System (INIS)

    To investigate the effects of increased UV-B radiation on a natural subarctic ecosystem a field irradiation experiment was established at Abisko, northern Sweden. The vegetation in the plots consists of a dwarf shrub layer with mosses and lichens beneath. Many response variables of the vegetation and soil are measured in these plots, e.g. photosynthesis, growth, phenology, changes in species composition and decomposition. This paper describes the methods used and some initial results. Decomposition was impaired by enhanced UV-B radiation. UV-B directly affected decomposition processes and also affected them indirectly by altering the tissue chemistry of leaves. The annual growth of the dwarf shrubs was lower under enhanced UV-B. This was more pronounced in evergreen than in deciduous species. Leaf thickness of the dwarf shrubs was changed by UV-B. The leaves of the evergreen Vaccinium vitis-idaea grew thicker, while those of the two deciduous species V. myrtillus and V. uliginosum grew thinner. In the moss Hylocomium splendens, the phenological development was accelerated under enhanced UV-B radiation. Its growth (number of primary branches, length and dry weight) also increased

  18. Exoemissive properties of graphite. [Gamma, beta, X, aud UV, radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lapraz, D.; Iacconi, P.; Keller, P. (Nice Univ., 06 (France). Lab. de Physique Experimentale); Barthe, J. (CEA Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Dept. de Protection)

    1983-01-01

    The exoemission of the commonly used graphite is far from negligible when the doses are higher than in the case of dosimetric applications. Some exoemissive experimental results for graphite, between room temperature and 710/sup 0/C, are given after various irradiations: UV (Hg - 253.7 nm), ..beta.. (/sup 90/Sr), X (W-target, 45 kV) or ..gamma.. (/sup 137/Cs). Mainly, six TSEE peaks located near 90, 160, 220, 300, 475 and 570/sup 0/C are observed. The origin of graphite exoemission is probably due to adsorption effects.

  19. Monitoring of Sun’s Uv Radiation and Stratospheric Ozone Layer Thickness over the Region of Novi Sad (Serbia)

    OpenAIRE

    Zoran Mijatović; R. Kobilarov Kobilarov; B. T. Vujičić; Mihailović, D. T.

    2013-01-01

    The results of the Sun’s UV radiation and stratospheric ozone layer thickness over the region of Novi Sad (Serbia) are reported. Monitoring the UV radiation and stratospheric ozone layer thickness started in 2003 and 2007 respectively. Results recorded during these years have been analyzed. Upon these analyses it can be concluded that during observational period, the significant difference in daily maxima of the UV radiation recordings or ozone seasonal maximal values from year to year, has n...

  20. RecBC enzyme overproduction affects UV and gamma radiation survival of Deinococcus radiodurans.

    Science.gov (United States)

    Khairnar, Nivedita P; Kamble, Vidya A; Misra, Hari S

    2008-01-01

    Deinococcus radiodurans recovering from the effect of acute dose of gamma (gamma) radiation shows a biphasic mechanism of DNA double strands breaks repair that involves an efficient homologous recombination. However, it shows higher sensitivity to near-UV (NUV) than Escherichia coli and lacks RecBC, a DNA strand break (DSB) repair enzyme in some bacteria. Recombinant Deinococcus expressing the recBC genes of E. coli showed nearly three-fold improvements in near-UV tolerance and nearly 2 log cycle reductions in wild type gamma radiation resistance. RecBC over expression effect on radiation response of D. radiodurans was independent of indigenous RecD. Loss of gamma radiation tolerance was attributed to the enhanced rate of in vivo degradation of radiation damaged DNA and delayed kinetics of DSB repair during post-irradiation recovery. RecBC expressing cells of Deinococcus showed wild type response to Far-UV. These results suggest that the overproduction of RecBC competes with the indigenous mechanism of gamma radiation damaged DNA repair while it supports near-UV tolerance in D. radiodurans. PMID:17720630

  1. Effect of enhanced UV-B radiation on yield and quality of rice

    International Nuclear Information System (INIS)

    The effects of enhanced UV-B radiation on yield and quality of two rice cuhivars(ShenNong 6014 and ShenNong 265) are studied in potted method. There were three treatments including natural light (TCK), enhanced 5% UV-B radiation (T) and enhanced 10% (T). The results showed that enhanced UV-B radiation decreases yield components, the percentage of brown rice (0.66%-7.06%), head rice rate (5.65%-18.88%), the rate of white rice (22.17%-40.16%), grain area (2.61%-6.25%), fatty acid contents (1.23%-54.19%) and eating quality (1.07%-16.78%) but increasea protein content (4.65%-10.71%) and amylose content of rice (0.56%-4.81%). The effects of T2 was stronger than T1

  2. Chloroplast genetics of chlamydomonas. I. Allelic segregation ratios. [UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sager, R.; Ramanis, Z.

    1976-06-01

    This paper presents allelic segregation data from a series of 16 crosses segregated for nuclear and chloroplast genes. By means of pedigree analysis, segregants of chloroplast genes. By means of pedigree analysis, segregants of chloroplast markers occurring in the zygote have been distinguished from those occurring in zoospore clones. The genes ac1, ac2, and tm1 showed little if any deviation from 1:1 either in zygotic segregation or in zoospore clones. The genes sm2, ery, and spc showed a significant excess of the allele from the mt+ parent in zygotes. However, in zoospores, mt+ excess was seen only when the allele was the mutant (resistant) form but not when it was wild type (sensitive). These results show that the extent of preferential segregation differs in zygotes and in zoospores, and that preferential segregation is influenced by map location and by allele specificity. A comparison of progeny from zygotes mated after 0, 15'', 30'', and 50'' uv irradiation of the mt+ gametes demonstrated the lack of an effect of uv upon allelic segregation ratios. In total, these results exclude the multi-copy model of chloroplast genome segregation suggested by Gillham. Boynton and Lee (1974) and support the diploid model we have previously proposed.

  3. Comparison of UV irradiation and p-fluorphenylaline as selective agents for production of aromatic compounds in plant cell culture

    International Nuclear Information System (INIS)

    Resistance to UV irradiation, and to the toxicity of p-fluorophenylalanine, can both be mediateted in plants by enhanced synthesis of aromatic compounds. These selective agents were applied to cell cultures of Nicotiana tabacum, Anchusa officinalis and Catharanthus roseur, and the production of aromatic metabolites in the resulting resistant lines of each species was compared. While Nicotiana and Anchusa cultures responded to each selective agent ith an enhanced accumulation of aromatic compounds, the Catharanthus cultures acquired resistance through other, unknown, mechanisms. Some degree of cross-resistance was observed between cultures selected individually for resistance to each agent (author). 26 refs.; 2 figs.; 1 tab

  4. Crosstalk between MAV and MEP pathways in vitro grape plants exposed to UV-B radiation

    International Nuclear Information System (INIS)

    The synthesis of terpenoids from IPP (isopentenyl diphosphate) proceeds in plants throughout two pathways, the MVA (mevalonic acid) in cytosol and the MEP (2-C-methyl-D-erythritol 4-phosphate) in plastids. Ultraviolet-B (UV-B) radiation induced the synthesis of terpenes in in vitro grape plants according to the fluence rate. Low intensity UV-B promoted the MVA pathway while high intensity UV-B stimulated the MEP pathway. Mevastatin is known to inhibit the enzyme HMG-CoA reductase blocking terpene synthesis in cytosol. In vitro plants growing 45 days under 16 h-photoperiod (100 μmol m-2 s-1) were fed at the apex with mevastatin and then exposed to an UV-B dose administrated at two intensities: low UV-B (8.25 μW cm-2,16 h) or high UV-B (33 μW cm-2,4 h). Methanol: chloroform extracts were analyzed by GC-EIMS and compared with controls without mevastatin. Levels of γ-Sitosterol and Stigmasterol were significantly increased under low intensity UV-B in the controls. The plants treated with the inhibitor showed a significant decrease of both sterols and a decrease in the plastidial terpenes but sterols were higher under UV-B. These results suggest an IPP crosstalk between the MAV and MEP pathways under restrictive conditions. (authors)

  5. Using the electron synchrotron radiation for the calibration of the spectral density in UV and long-wave vacuum UV range (160 nm to 340 nm)

    International Nuclear Information System (INIS)

    Electron synchrotron radiation was investigated with a view to the development of methods for the calibration of the spectral density in the UV and long-wave vacuum UV spectral regions. The relative spectral radiation flow of a synchrotron can be calculated over a wide spectral region. In order to determine the absolute radiation flow in the vaccum UV, the synchrotron radiation in the visible region is compared with a reference source (calibrated tungsten filament lamp). Between 160 nm and 340 nm, the spectral beam density calibration with the synchrotron radiation is uncertain by about +- 5%. Between 280 nm and 340 nm, calibrations of deuterium lamps at the synchrotron and at a cavity radiator vary by less than 10%. (orig./WL)

  6. Generation of powerful narrow-band UV radiation for isotope separation by laser

    International Nuclear Information System (INIS)

    The laser system for production of the narrow-band rearranged laser radiation in UV band of the spectrum for ALVIS was created. The system is defined as two independent laser channels radiating each on its own wavelength. The radiation of the continuos dye laser is increased by tree-cascade strengthening system involving containers with the transverse pumping by radiation of the copper vapor laser. Two identical laser systems, which were used for isotopically selective excitation of zinc atoms in the heated cell, were realized. Excitation of atoms was done at the 6s3S1 step during consumption of the two counter photons (λ1 = 307.6 nm and λ2 = 303.6 nm). The UV radiation width of line was mapped by the peaks less than 40 MHz

  7. Combined impact of solar UV-B radiation and selenium treatment on respiratory potential in pumpkins (Cucurbita pepo L.)

    International Nuclear Information System (INIS)

    The effects of ambient and filtered solar UV-B radiation and of selenium treatment on respiratory potential measured by electron transport system (ETS) activity in pumpkins, Cucurbita pepo L. were studied. Measurements were conducted three times in the growth period. Solar UV-B radiation decreased ETS activity in plants, regardless selenium treatment. The results suggested that the solar UV-B radiation impaired flow of electrons in the respiratory chain. Selenium decreased ETS activity in plants exposed to solar UV-B radiation in the end of the vegetation period

  8. Dependence of erythemally weighted UV radiation on geographical parameters in the United States

    Science.gov (United States)

    Wang, Xinli; Gao, Wei; Davis, John; Olson, Becky; Janson, George; Slusser, James

    2007-09-01

    The relationship between solar ultraviolet (UV) radiation reaching the Earth's surface and geographical parameters is helpful in estimating the spatial distribution of UV radiation, which provides useful information to evaluate the potential impacts of enhanced UV levels on human health, agriculture, environment, and ecosystems for sustainable development. Measurements of erythemally weighted UV radiation at the sites of the United States Department of Agriculture UV-B Monitoring and Research Program (UVBMRP) monitoring network were analyzed to investigate the geographical distribution and seasonal variations. Twenty nine observation sites, which had continuous measurements during the recent six years, are selected for this study; twenty seven of them are distributed in the United States, including one in Hawaii and one in Alaska, and two of them are located in Canada along the United States border. The measurements were taken using the Yankee Environmental Systems Inc. (YES) UVB-1 ultraviolet pyranometer. This work focuses the data from the recent six years of 2001-2006 and the measurements during summer months (June-August) are emphasized. For each day, the measurements are integrated from sunrise to sunset to produce the daily UV dosage, which is then averaged for different seasons or for the whole year over the six years to generate the average daily UV dosage. A multivariable regression technique is exploited to characterize the dependence of UV dosages on geographical parameters, including latitude and altitude. The results show that, although there are many factors, such as clouds, ozone, aerosols, air pollutants, and haze, that affect the UV radiation intensity at a location, the latitude and altitude of the site are the primary factors that regulate the average daily UV dosage. On average over the last six years in the United States, more than 95% of the variability in averaged daily UV dosages can be explained by the latitude and altitude. Longitude is

  9. 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

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

    CERN Document Server

    Sobacchi, Emanuele

    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 simulations with large-scale models of reionization. In the resulting reionization models, the ionizing emissivity of galaxies depends on the local values of the reionization redshift and the UVB intensity. We present a physically-motivated analytic expression for the average minimum mass of star-forming galaxies, which can be readily used in modeling galaxy formation. We find that UVB feedback: (i) delays the end stages of reionization by less than 0.5 in redshift; (ii) results in a more uniform distribution of HII regions, ...

  11. 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

  12. Interaction of UV-radiation and IAA during growth of seedlings and hypocotyl segments of sunflower

    International Nuclear Information System (INIS)

    Stem growth of sunflower seedlings (Helianthus annuus, c.v. Polstar L.) was increasingly reduced by UV-B radiation with shorter wavelengths (Schott cut-off filters: WG 360-280) at a constant low white light irradiance. The reduction in stem elongation measured with linear voltage transformers was observed after 10 h of enhanced UV-B irradiation (WG 305) and already after 5 h, when the seedlings were additionally irradiated with lateral shortwave UV-B (WG 305 hi.). Stem elongation of UV-B irradiated sunflower seedlings was not irreversibly reduced as demonstrated by changing UV-B irradiation conditions. UV-B irradiation (WG 305) had no negative influence on stem elongation when the hypocotyls were covered by a non-UV-B transmitting plastic film, indicating that the hypocotyl is most susceptible for the inhibiting effect of UV-B radiation on stem elongation. Elongation growth of isolated hypocotyl segments (HSEG-test) at simultaneous UV-B irradiation was inhibited both in water and IAA solution, dependent on wavelength in the UV-B range. In IAA solutions UV-B preirradiated for 1-48h under a WG 305 filter, elongation growth of segments decreased with preirradiation time. It was assumed that a destruction of IAA and/ or a formation of growth inhibiting IAA photoproducts in the IAA solution are reasons for the observed growth reduction. Therefore, IAA-photooxidation kinetics were studied, the IAA photoproducts separated by HPLC and identified as 3-Hydroxymethyloxindole, Indole-3-aldehyde, 3-Methyleneoxindole (3-M), 3-Methyloxindole and Indole. The application of these compounds in the HSEG-test showed that only 3-M inhibited elongation growth. Furthermore, the in vivo IAA concentration of UV-B irradiated sunflower seedlings under WG 305 was reduced by 51% compared with that of seedlings grown under WG 360. On the basis of these results the «IAA destruction» seems to be a potent mechanism for the growth inhibition of UV-B irradiated sunflower seedlings grown at low

  13. Effect of UV and γ-radiation on polychromatic glass

    International Nuclear Information System (INIS)

    Color centers related to silver (Ag+)- and bromine were detected in polychromatic glasses (PCG). It was shown that the paramagnetic centers (PC) related to bromine (centers to which the signal with gef = 2.212 and (Br2)- PC corresponds) primarily arise in γ-radiation of the glass and significantly contribute to the additional absorption at the 360 nm wavelength

  14. The effects of UV-B radiation on loblolly pine. 3. Interaction with CO2 enhancement

    International Nuclear Information System (INIS)

    Projected depletions in the stratospheric ozone layer will result in increases in solar ultraviolet-B radiation (290–320 nm) reaching the earth's surface, These increases will likely occur in concert with other environmental changes such as increases in atmospheric carbon dioxide concentrations. Currently very little information is available on the effectiveness of UV-B radiation within a CO2-enriched atmosphere, and this is especially true for trees. Loblolly pine (Pinus taeda L.) seedlings were grown in a factorial experiment at the Duke University Phytotron with either 0, 8.8 or 13.8 kJ m−2 of biologically effective UV-B radiation (UV-BBE). The CO2 concentrations used were 350 and 650 μmol mol−1. Measurements of chlorophyll fluorescence were made at 5-week intervals and photosynthetic oxygen evolution and leaf pigments were measured after 22 weeks, prior to harvest. The results of this study demonstrated a clear growth response to CO2 enrichment but neither photosynthetic capacity nor quantum efficiency were altered by CO2. The higher UV-B irradiance reduced total biomass by about 12% at both CO2 levels but biomass partitioning was altered by the interaction of CO2 and UV-B radiation. Dry matter was preferentially allocated to shoot components by UV-B radiation at 350 μmol mol−1 CO2 and towards root components at 650 μmol mol−1 CO2. These subtle effects on biomass allocation could be important in the future to seedling establishment and competitive interactions in natural as well as agricultural communities

  15. Does exposure to UV radiation induce a shift to a Th-2-like immune reaction?

    International Nuclear Information System (INIS)

    In addition to being the primary cause of skin cancer, UV radiation is immune suppressive and there appears to be a link between the ability of UV to suppress the immune response and induce skin cancer. Cytokines made by UV-irradiated keratinocytes play an essential role in activating immune suppression. In particular, we have found that keratinocyte-derived interleukin (IL)-10 is responsible for the systemic impairment of antigen presenting cell function and the UV-induced suppression of delayed-type hypersenstivity (DTH). Antigen presentation by splenic adherent cells isolated from UV-irradiated mice to T helper-1 type T (Th1) cells is suppressed, whereas antigen presentation to T helper-2 type T (Th2) cells is enhanced. The enhanced antigen presentation to Th2 cells and the impaired presentation to Th1 cells can be reversed in vivo by injecting the UV-irradiated mice with monoclonal anti-IL-10 antibody. Furthermore, immune suppression can be transferred from UV-irradiated mice to normal recipients by adoptive transfer of T cells. Injecting the recipient mice with anti-IL-4 or anti-IL-10 prevents the transfer of immune suppression, suggesting the suppressor cells are Th2 cells. In addition, injecting UV-irradiated mice with IL-12, a cytokine that has been shown to be the primary inducer of Th1 cells, and one that prevents the differentiation of Th2 cells in vivo, reverses UV-induced immune suppression. These findings support the hypothesis that UV exposure activates IL-10 secretion, which depresses the function of Th1 cells, while enhancing the activity of Th2 cells. (Author)

  16. Investigations of the effects of UV and X-ray radiation and the repair of radiation damage in the ciliate Stylonychia mytilus

    International Nuclear Information System (INIS)

    Using the example of Stylomychia mytilus, the effects of UV-radiation and ionizing X-ray radiation are compared. The effects on cell division and on the repair of radiation damage in DNA are compared. Sensitivity to UV radiation differs between the stages of the cell cycle while the effects of X-ray radiation are independent of phase. There is no difference in repair processes. (AJ) 891 AJ/AJ 892 MKO

  17. Influence of light, UV-B radiation, and herbicides on wax biosynthesis of cucumber seedlings

    International Nuclear Information System (INIS)

    The behavior of cuticular alkane-1-ols and alkanes were studied in different developmental stages of cucumber seedlings grown in the dark or under white light, with or without UV-B radiation or in presence of wax biosynthesis inhibitors, trichloroacetic acid and metolachlor. Accumulation of alkane-1-ols increased light independently with seedling age. Synthesis of alkanes was strictly light and dose dependent. Addition of UV-B radiation did not alter the amounts of alkanes or alcohols, however, the distribution of homologues was shifted towards shorter chain homologues. Treatments with Cl3AcOH resulted in strong inhibition of alkane accumulation, whereas the amount of alkane-1-ols was changed neither at low nor at moderate concentrations of Cl3AcOH but their homologue distribution shifted towards longer chain lengths. This shifting was depressed in the presence of UV-B. At high concentrations of Cl3Ac0H similar homologue distributions as produced by UV-B (shift to shorter homologues) were observed. Metolachlor treatment resulted in an inhibition of alkane-1-ol production connected with rising amounts of alkanes, predominantly of short chain species. A simple model of wax biosynthesis is proposed which describes the interactions with white light, UV-B radiation and herbicides. (author)

  18. Simulation of increasing UV radiation as a consequence of ozone depletion

    Science.gov (United States)

    Diaz, Susana B.; Camilion, Carolina; Lacoste, Karine; Escobar, Julio; Demers, Serge; Gianesella, Sonia M. F.; Roy, Suzanne

    2003-11-01

    UV plays a key roll in several biological functions. As consequence of the ozone depletion investigations to study the effects of UV radiation on human health and terrestrial and aquatic ecosystems have been carried out in laboratories and in the field. Experiments performed in laboratories, irradiating samples with lamps often present the inconvenience that light sources do not reproduce properly the solar spectrum. Field experiments are usually carried out comparing samples exposed to ambient irradiance (normal or increased) against 100% UV-B screened samples. This scenario also differs from the real situation of normal irradiance against UV-B increased irradiance. Some authors have solved this problem performing studies under ambient conditions, simulating the ozone depletion by supplementation of the UV-B radiation with lamps. As part of the IAI CNR-26, "Enhanced Ultraviolet-B Radiation in Natural Ecosystems as an added Perturbation due to Ozone Depletion," mesocosms experiments were performed at Rimouski, Canada), Ubatuba (Brasil) and Ushuaia, Argentina) using the supplementing methodology. In this paper we introduce the design of the measurements and lamps setting and the methodology used to calculate the attenuation constant and the irradiance at the water column at the mesocosms during the experiment, emphasizing on the Ubatuba campaign.

  19. Involvement of pnp in survival of UV radiation in Escherichia coli K-12.

    Science.gov (United States)

    Rath, Devashish; Mangoli, Suhas H; Pagedar, Amruta R; Jawali, Narendra

    2012-05-01

    Polynucleotide phosphorylase (PNPase), a multifunctional protein, is a 3'→5' exoribonuclease or exoDNase in the presence of inorganic phosphate (P(i)), and extends a 3'-OH of RNA or ssDNA in the presence of ADP or dADP. In Escherichia coli, PNPase is known to protect against H(2)O(2)- and mitomycin C-induced damage. Recent reports show that Bacillus subtilis PNPase is required for repair of H(2)O(2)-induced double-strand breaks. Here we show that absence of PNPase makes E. coli cells sensitive to UV, indicating that PNPase has a role in survival of UV radiation damage. Analyses of various DNA repair pathways show that in the absence of nucleotide excision repair, survival of UV radiation depends critically on PNPase function. Consequently, uvrA pnp, uvrB pnp and uvrC pnp strains show hypersensitivity to UV radiation. Whereas the pnp mutation is non-epistatic to recJ, recQ and recG mutations with respect to the UV-sensitivity phenotype, it is epistatic to uvrD, recB and ruvA mutations, implicating it in the recombinational repair process. PMID:22322961

  20. Effects of the ultraviolet-B radiation (UV-B) on conifers: a review

    International Nuclear Information System (INIS)

    The current knowledge on conifer responses to enhanced ultraviolet-B (UV-B) radiation is mainly based on greenhouse or growth chamber experiments of one growing season in duration. However, the biomass losses observed in greenhouses do not occur in field-grown trees in their natural habitats. Moreover, the majority of the 20 conifer species studied have been 1-year-old seedlings, and no studies have been undertaken on mature trees. Fully grown needles, with their glaucous waxy surfaces and thick epidermal cells with both soluble and wall-bound UV-B screening metabolites, are well protected against UV-B radiation. However, it is not known whether these are sufficient protectants in young emerging needles or during the early spring period of high UV-B levels reflected from snow. In order to understand all the mechanisms that result in the protection of conifer needles against UV-B radiation, future research should focus on the epidermal layer, separating the waxes, cuticle and epidermal and hypodermal cells. Parallel studies should consist of wall-bound and soluble secondary metabolite analysis, antioxidant measurements and microscopic observations. (author)

  1. 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.

  2. Does enhanced solar UV-B radiation affect marine primary producers in their natural habitats?

    Science.gov (United States)

    Häder, Donat-P

    2011-01-01

    This article is a highlight of the paper by Li et al. in this issue of Photochemistry and Photobiology as well as a short summary of the research on the effects of solar UV-B radiation on primary production in the oceans. Laboratory experiments under controlled conditions using artificial light sources indicate species-specific damage of many phytoplankton groups. Mesocosm studies in enclosures of limited volume allow analyzing UV effects in multigeneration monitoring of natural assemblages. Field studies to determine the effects of short-wavelength solar radiation require sensitive instrumentation and measurements over extended areas of the open ocean to yield significant results. Results from a cruise described in the paper by Li et al. indicate clear effects of UV-B and UV-A on the photosynthetic carbon fixation of phytoplankton communities with spatial differences between coastal and open-ocean waters. Increasing temperatures and acidification in the ocean due to global climate change may exacerbate the detrimental effects of solar UV-B radiation. PMID:21208211

  3. 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

  4. Research on the Signals of Cotton in Response to UV-B Radiation%棉花响应UV-B辐射的信号初探

    Institute of Scientific and Technical Information of China (English)

    侍福梅; 孟慧敏; 王超

    2011-01-01

    Phenotype and hydrogen peroxide and nitric oxide were studied in three kinds of cotton under ultraviolet-B (UV-B) radiation with or without SNP and ABA treatment. The results indicated that leaves of cotton seedlings showed obvious rust, and leaves in vitro dehydrate apparently suffering UV-B stress, Pretreatment with sudium nitroprusside (SNP) and abscisic acid (ABA) lightened rust and wilt symptom of the leaves due to UV-B radiation. Both hydrogen peroxide (H2 O2) dyed with 3, 3-diaminobenzidine (DAB) and nitric oxide (NO) labelled by 4,5-diaminofluorescein diacetate (DAF-2DA) were increased after UV-B radiation than untreated control. And the release of NO alleviated the damage from UV-B radiation by reducing the accumulation of H2O2. In additon, pretreatment with ABA significantly increased the tolerance of cotton, which is bound up with the production of R2O2 and NO. Therefore, UV-B radiation caused damage of cotton during the growth and development , and all of H2 O2, NO and ABA are members of the signal transduction during the interaction between cotton and UV-B stress.%以3种棉花为供试材料,研究紫外线-B(UV-B)辐射及外源SNP、ABA叠加处理对棉花幼苗表观形态及内源H2O2与NO水平的影响.结果表明,UV-B辐射引起棉花幼苗叶片呈现锈色伤斑,离体叶片明显失水萎蔫.叶片外源涂抹SNP、ABA能减轻UV-B辐射引起的幼叶伤斑与萎蔫症状,缓解UV-B辐射所造成的伤害.DAB及DAF-2DA染色结果显示,UV-B辐射引起棉花内源H2O2与NO含量增加,面NO的释放通过减少H2O2积累减轻紫外辐射对棉花的伤害.ABA预处理可增强棉花对紫外伤害的耐受能力,且与H2O2与NO的释放密切相关.UV-B辐射对棉花生长造成伤害,H2O2、NO及ABA都参与棉花应答UV-B胁迫的信号转导过程.

  5. Effects of UV-A Radiation on Desmodesmus armatus: Changes in Growth Rate, Pigment Content and Morphological Appearance

    Science.gov (United States)

    Pálffy, Károly; Vörös, Lajos

    2006-10-01

    Laboratory cultures of Desmodesmus armatus (R. Chod.) Hegew. were grown under different levels of photosynthetically active radiation (PAR) supplemented with 3.75 mW . cm-2 UV-A radiation. Growth rate was monitored daily, chlorophyl-a concentration, total carotenoid content, cell number and the relative abundance of different coenobial forms was determined at the end of each experiment. Exposure to UV-A radiation resulted in an increasing inhibition of growth towards higher PAR levels, reaching 100% at 400 μmol . m-2 . s-1. Cellular carotenoid content was higher in the presence of UV-A radiation, on the other hand no differences were observed in cellular chlorophyll-a concentration. UV-A radiation also induced changes in coenobium formation with a decreasing proportion of 4-celled coenobia and an increase in the abundance of 2-celled and teratologic coenobia, suggesting that high intensity UV-A radiation may influence cell cycle events or morphology development.

  6. Physiological Defense Mechanism of Ligularia intermedia Against UV-B Radiation on Dongling Mountain

    Institute of Scientific and Technical Information of China (English)

    李鑫; 贾顺姬; 简嘉; 林孟仪; 李骑昂; 黄晓春; 张超; 张荣庆; 张贵友

    2003-01-01

    Ligularia intermedia growing at different altitudes were used to investigate the mechanism of ultraviolet (UV)-resistance on physiological aspects in the field.The tests compared the absorbance of the UV-absorbing compound, the content of chlorophyll a, chlorophyll b, and carotenoids, and the activities of peroxidase (POX) and superoxide dismutase (SOD) in Ligularia intermedia growing at three different altitudes on Dongling Mountain in northern China.There were no significant differences between the plants growing at 1160 m and 1820 m.However, all of these factors increased dramatically at 2190 m.The results indicate that the UV-resistance of the plants mainly depends on the mechanism of filtering the radiation and preventing the reactive oxygen species (ROS) damage produced by UV-B.

  7. UV radiation and freshwater zooplankton: damage, protection and recovery

    OpenAIRE

    Rautio, Milla; Tartarotti, Barbara

    2010-01-01

    While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiologi...

  8. Ultrastructural analysis of corneal exposure to UV radiation

    International Nuclear Information System (INIS)

    The primate cornea was exposed to 300 nm UVR with five levels of radiant expsure from 0.08 to 0.6 Jcm-2. All cellular layers of the cornea were damaged at the 0.08 Jcm-2 exposure, and damage became more severe as the exposure level was increased. The corneal cells showed variable response in that essentially normal cells were found among damaged cells. Eight days post-exposure using the 0.6 Jcm-2 level, the epithelium had regained its normal thickness and was populated largely by normal appearing cells; however, the stroma showed damaged keratocytes and the loss of keratocytes. The corneal basement membranes (the epithelial basement membrane and the posterior limiting lamina) and the anterior limiting lamina were not damaged at any exposure level except for an isolated area along the epithelial basement membrane in one cornea. Therefore, one is lead to conclude that basement membranes are unaffected by UVR. The endothelium continued to demonstrate the loss of mitochondria, endoplasmic reticulum and some vacuoles at 8 days after exposure. However, the endothelium appeared to have resumed its physiological function as demonstrated by the reduced stromal oedema. This research gives the first complete description of UV-B induced corneal damage and repair of the full, in-depth cornea of the primate using the EM. (author)

  9. Ultrastructural analysis of corneal exposure to UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Pitts, D.G.; Bergmanson, J.P.G.; Chu, L.W.-F.

    1987-01-01

    The primate cornea was exposed to 300 nm UVR with five levels of radiant expsure from 0.08 to 0.6 Jcm/sup -2/. All cellular layers of the cornea were damaged at the 0.08 Jcm/sup -2/ exposure, and damage became more severe as the exposure level was increased. The corneal cells showed variable response in that essentially normal cells were found among damaged cells. Eight days post-exposure using the 0.6 Jcm/sup -2/ level, the epithelium had regained its normal thickness and was populated largely by normal appearing cells; however, the stroma showed damaged keratocytes and the loss of keratocytes. The corneal basement membranes (the epithelial basement membrane and the posterior limiting lamina) and the anterior limiting lamina were not damaged at any exposure level except for an isolated area along the epithelial basement membrane in one cornea. Therefore, one is lead to conclude that basement membranes are unaffected by UVR. The endothelium continued to demonstrate the loss of mitochondria, endoplasmic reticulum and some vacuoles at 8 days after exposure. However, the endothelium appeared to have resumed its physiological function as demonstrated by the reduced stromal oedema. This research gives the first complete description of UV-B induced corneal damage and repair of the full, in-depth cornea of the primate using the EM.

  10. Effects of UV-B radiation on tetraspores of Chondrus ocellatus Holm (Rhodophyta), and effects of red and blue light on repair of UV-B-induced damage

    Science.gov (United States)

    Ju, Qing; Xiao, Hui; Wang, You; Tang, Xuexi

    2015-05-01

    We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels (0, 36, 72, 108, 144 and 180 J/m2), and thereafter subjected to PAR, darkness, or red or blue light during a 2-h repair stage, each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers (CPDs), chlorophyll a (Chl a), phycoerythrin, and UV-B-absorbing mycosporinelike amino acids (MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation (36 and 72 J/m2) promoted the growth of C. ocellatus; however, increased UV-B radiation gradually reduced the C. ocellatus growth (greater than 72 J/m2). The MAAs (palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition, photorepair was inhibited by red light, so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase, greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore, PAR, red light, and blue light play different roles during the repair processes for damage induced by UV-B radiation.

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

    Directory of Open Access Journals (Sweden)

    F. Jégou

    2011-06-01

    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.

  12. Beneficial effects of UV radiation other than via vitamin D production

    OpenAIRE

    Juzeniene, Asta; Moan, Johan

    2012-01-01

    Most of the positive effects of solar radiation are mediated via ultraviolet-B (UVB) induced production of vitamin D in skin. However, several other pathways may exist for the action of ultraviolet (UV) radiation on humans as focused on in this review. One is induction of cosmetic tanning (immediate pigment darkening, persistent pigment darkening and delayed tanning). UVB-induced, delayed tanning (increases melanin in skin after several days), acts as a sunscreen. Several human skin diseases,...

  13. Investigation of the solar UV/EUV related changes in the Jovian radiation belt and thermosphere

    Science.gov (United States)

    Kita, H.; Misawa, H.; Bhardwaj, A.; Tsuchiya, F.; Tao, C.; Sakanoi, T.; Miyoshi, Y.; Kasaba, Y.; Morioka, A.

    2013-09-01

    In order to investigate atmospheric heating effect by the solar UV/EUV on the Jovian Radiation Belt, we made coordinated observations using a radio interferometer and an infrared telescope. The total flux density of Jovian Synchrotron Radiation (JSR) increased from 6th Nov to 13th Nov in 2011 by about 5%, corresponding to the solar UV/EUV variations. The infrared H3+ emission also increased from 7th Nov. to 12th Nov. by 20-30%. These support a theoretical expectation that solar UV/EUV heating for the Jovian thermosphere drives neutral wind perturbations, then the induced dynamo electric field increases the total radio flux density. On the other hand, radio images showed that the equatorial emission peak moved outward by about 0.2 Jovian radii. These observation results showed that the variation of JSR at this time was caused by not global but non-uniform enhancement of radial diffusion.

  14. Effects of enhanced UV-B radiation on Mentha spicata essential oils

    International Nuclear Information System (INIS)

    In vitro propagated plantlets representing two distinct chemotypes of Mentha spicata, viz. plants producing essential oils rich in piperitone oxide and piperitenone oxide (chemotype I) and rich in carvone and dihydrocarvone (chemotype II), were grown in the field under ambient or ambient plus supplemental UV-B radiation, biologically equivalent to a 15% ozone depletion over Patras (38.3°N, 29.1°E), Greece. Enhanced UV-B radiation stimulated essential oil production in chemotype II substantially, while a similar, non-significant trend was observed in chemotype I. No effect was found on the qualitative composition of the essential oils, whereas the quantitative composition was slightly modified in chemotype I. This is the first investigation reporting an improved essential oil content under UV-B supplementation in aromatic plants under field conditions

  15. Room-temperature effects of UV radiation in KBr:Eu{sup 2+} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Salas, R.; Melendrez, R. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada - IFUNAM, Ensenada, Apartado Postal 2732 Ensenada, BC, 22800 (Mexico); Aceves, R.; Rodriguez, R.; Barboza-Flores, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088 Hermosillo, Sonora, 83190 (Mexico)

    1996-07-01

    Thermoluminescence and optical absorption measurements have been carried out in KBr:Eu{sup 2+} crystals irradiated with monochromatic UV light (200-300 nm) and x-rays at room temperature. For UV- and x-irradiated crystals strong similarities between the thermoluminescence glow curves have been found, suggesting that the low-energy UV radiation produces the same defects as produced by x-irradiation in this material. The thermoluminescence glow curves are composed of six glow peaks located at 337, 383, 403, 435, 475 and 509 K. Thermal annealing experiments in previously irradiated crystals show clearly a correlation between the glow peak located at 383 K and the F-centre thermal bleaching process. Also, the excitation spectrum for each thermoluminescence glow peak has been investigated, showing that the low-energy radiation induces the formation of F centres. (author)

  16. The effect of additives on the enhancement of methyl methacrylate grafting to cellulose in the presence of UV and ionising radiation

    International Nuclear Information System (INIS)

    The role of various additives in the grafting of methyl methylacrylate (MMA) to cellulose using UV and ionising radiation has been investigated. MMA grafting yields are hampered by competing homopolymerisation. The styrene comonomer technique was utilised to overcome this problem. The role of acid in these reactions has been studied as well as additives like, an inclusion compound (urea), thermal initiators and photoinitiators. Methanol was used as the swelling agent in all the experiments. Molecular weight studies with homopolymers indicate that both chemical and physical processes are involved in the mechanism of the reaction. The physical process involves a partitioning phenomenon whereas the chemical process concerns additional radical reactions in the radiation initiation step. This grafting mechanism is shown to be applicable to the simple radiation polymerisation of monomers in solution and also analogous UV fast curing systems. (author)

  17. DSMC simulation of two-phase plume flow with UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jie; Liu, Ying; Wang, Ning; Jin, Ling [College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, Hunan, 410073 (China)

    2014-12-09

    Rarefied gas-particle two-phase plume in which the phase of particles is liquid or solid flows from a solid propellant rocket of hypersonic vehicle flying at high altitudes, the aluminum oxide particulates not only impact the rarefied gas flow properties, but also make a great difference to plume radiation signature, so the radiation prediction of the rarefied gas-particle two-phase plume flow is very important for space target detection of hypersonic vehicles. Accordingly, this project aims to study the rarefied gas-particle two-phase flow and ultraviolet radiation (UV) characteristics. Considering a two-way interphase coupling of momentum and energy, the direct simulation Monte Carlo (DSMC) method is developed for particle phase change and the particle flow, including particulate collision, coalescence as well as separation, and a Monte Carlo ray trace model is implemented for the particulate UV radiation. A program for the numerical simulation of the gas-particle two-phase flow and radiation in which the gas flow nonequilibrium is strong is implemented as well. Ultraviolet radiation characteristics of the particle phase is studied based on the calculation of the flow field coupled with the radiation calculation, the radiation model for different size particles is analyzed, focusing on the effects of particle emission, absorption, scattering as well as the searchlight emission of the nozzle. A new approach may be proposed to describe the rarefied gas-particle two-phase plume flow and radiation transfer characteristics in this project.

  18. 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...

  19. GROWTH RESPONSE OF SYMBODINIUM SPP. TO COMBINED TEMPERATURE AND UV RADIATION

    Science.gov (United States)

    Rogers, J.E. and D. Marcovich. In press. Growth Response of a Coral Symbiont, Symbiodinium sp., to Combined Temperature and UV Radiation Exposure (Abstract). To be presented at the ASLO 2004 Summer Meeting: The Changing Landscapes of Oceans and Freshwater, 13-18 June 2004, Savann...

  20. UV radiation: a promising tool in the synthesisof multicomponent nano-oxides

    Czech Academy of Sciences Publication Activity Database

    Čuba, V.; Procházková, L.; Bárta, J.; Vondrášková, A.; Pavelková, T.; Mihóková, Eva; Jarý, Vítězslav; Nikl, Martin

    2014-01-01

    Roč. 16, č. 11 (2014), "2686-1"-"2686-7". ISSN 1388-0764 R&D Projects: GA ČR GA13-09876S Institutional support: RVO:68378271 Keywords : nanoscintillators * band-gap engineering * UV radiation radioluminescence * zinc oxide * synthetic garnets * composite nanoparticles Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 2.184, year: 2014

  1. Effects of solar UV radiation on alkaloid production in Erythroxylum novogranatense var. novogranatense

    Science.gov (United States)

    Cocaine-producing species of Erythroxylum have been cultivated in South America for centuries, yet little is know of environmental effects on alkaloid production in these species. Given the high incidence of UV radiation in the equatorial and high altitude environments in which cocaine-producing sp...

  2. A Complex of Imaging Diagnostic Devices of Vacuum UV Radiation for the GOL-3 Multimirror Trap

    Czech Academy of Sciences Publication Activity Database

    Burdakov, A. V.; Weinzettl, Vladimír; Piffl, Vojtěch; Polosatkin, S. V.; Postupaev, V. V.

    2004-01-01

    Roč. 47, č. 2 (2004), s. 234-239. ISSN 0020-4412 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma diagnostics, spectroscopy, UV radiation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.312, year: 2004

  3. Empirical model for estimating daily erythemal UV radiation in the Central European region

    Czech Academy of Sciences Publication Activity Database

    Hlavinka, P.; Trnka, M.; Semerádová, Daniela; Žalud, Z.; Dubrovský, Martin; Eitzinger, J.; Weihs, P.; Simic, S.; Blumthaler, M.; Schreder, J.

    2007-01-01

    Roč. 16, č. 2 (2007), s. 183-190. ISSN 0941-2948 R&D Projects: GA MZe QG60051 Institutional research plan: CEZ:AV0Z30420517 Keywords : erythemal UV radiation * empirical model * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.986, year: 2007

  4. Surface photopolymerization of styrene under the effect of laser UV radiation

    International Nuclear Information System (INIS)

    Precipitation of polymer films from styrene vapors on the surface of a metal in conditions of exposure to pulsed laser UV radiation (λ = 266 nm) was studied by piezoelectric crystal microweighing and IR spectroscopy. The bulk and surface channels of initiation of reactions on the surface were distinguished and their contribution to the kinetics of the growth of polymer films was estimated

  5. 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 cappin

  6. UV radiation induced stress does not affect DMSP synthesis in the marine prymnesiophyte Emiliania huxleyi

    NARCIS (Netherlands)

    van Rijssel, M; Buma, A.G.J.

    2002-01-01

    A possible coupling between UV radiation (UVR; 280 to 400 nm) induced stress and the production of dimethylsulfoniopropionate (DMSP), the precursor of the climate-regulating gas dimethylsulfide (DMS), was investigated in the marine prymnesiophyte Emiliania huxleyi. To this end, axenic cultures of E.

  7. Effect of enhanced UV-B radiation on leaf surface and anatomy

    International Nuclear Information System (INIS)

    The purpose of the present investigations was to study the effects of enhanced UV-B radiation on anatomy and leaf surface of some crop plants during the first period of growth. The morphological changes of leaf surface are shown by SEM, biochemical changes in leaf surface compounds are described elsewhere (Steinmueller and Tevini 1982, this volume). (orig.)

  8. 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

    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...

  9. Electron beam radiation of resin luting agents - a cytotoxic evaluation

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate and compare the cytotoxicity of three resin luting agents rely x luting cement, rely x luting 2 cement, and clearfil SA luting agent on human dental pulp cells before and after electron beam irradiation. Growth and maintenance of cell cultures of human pulp cells was done in Dulbecco's modified Eagle's Medium (DMEM). The test samples were divided into two categories based on radiation exposure, irradiated category and non-radiated category. Samples in Irradiated category were exposed to electron beam radiation after dose standardisation (Microtron, Electron Beam Accelerator, Microtron Centre, Mangalore University). The dose of radiation used was 200 Gy. Two subgroups of radiated category were made. In 1st sub-group (containing 18 samples), all the 3 luting cements will be placed in sterile packets and irradiated without mixing the two components. In 2nd sub-group (containing 18 samples), all the 3 luting cements will be mixed separately, placed in sterile packets and exposed to electron-beam radiations. Samples in non radiated category were also made 2 groups. In 1st sub-group (containing 18 samples), all the 3 luting cements will be placed in sterile teflon moulds and kept in a humid chamber at 37℃ without mixing the two components. In 2nd sub-group (containing 18 samples), all the 3 the luting cements will be mixed separately, placed in sterile teflon moulds and kept in a humid chamber at 37℃. All the samples were subjected to MTT assay and spectrophotometric analysis and their cytotoxicity was assessed. (author)

  10. PLANT PROTECTIVE RESPONSE TO ENHANCED UV-B RADIATION UNDER FIELD CONDITIONS: LEAF OPTICAL PROPERTIES AND PHOTOSYNTHESIS

    Science.gov (United States)

    Plants of Vicia faba were grown in the field during early to midsummer while receiving two levels of supplemental UV-B radiation. Light-saturated photosynthesis and stomatal diffusive conductance of intact leaves did not show any indications of UV-radiation damage. Supplemental U...

  11. 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.

  12. Influences of the Clearness Index on UV Solar Radiation for Two Locations in the Tibetan Plateau-Lhasa and Haibei

    Institute of Scientific and Technical Information of China (English)

    HU Bo; WANG Yuesi; LIU Guangren

    2008-01-01

    Ultraviolet (UV) solar radiation has a significant influence on human health,the environment and climate. A series of measurements,including UV radiation(290-400 nm)and global solar radiation(Rs),were continuously recorded from August 2004 at the Lhasa and Haibei sites on the Tibetan Plateau.Both observation sites'altitudes are above 3000 m and have similar meteorological conditions.The data from 2005-2006 Was used to identify the varying characteristics of UV radiation.It'S relation to the clearness index Ks,the relative optical mass mr,and Rs were established.The annual mean values of total daily UV radiation are 0.92 and 0.67 MJ m-2 at Lhasa and Haibei,respectively.The UV radiation in Lhasa represented 4.6%of the global solar radiation while in Haibei this percentage was 4.2%.In the case of clear days (Ks>0.8),these percentages ranged between 4.O%and 4.5%in Lhasa and between 5.1%and 5.5% in Haibei.In the case of cloudy days(Ks<0.4),these percentages ranged from 4.4%to 6.8%in Lhasa and from 5.1%to 5.5%in Haibei.The maximum values of UV radiation for each relative optical mass diminished exponentially with mr.Thus,for Lhasa and Haibei,UV=46.25mn-1.29,and UV=51.76mr-1.42,respectively.The results of this study can be used to obtain more UV radiation data for the study of UV climate characteristics,the effects of UV on ecological processes and the feedback of the thinning of the stratospheric ozone.from more routine measurements Rs data.

  13. UV radiation in marine ectotherms: Molecular effects and responses

    International Nuclear Information System (INIS)

    This review summarizes current knowledge on ultraviolet radiation (UVR)-induced cellular and molecular damage in marine ectotherms (invertebrates and fish). UVR impairs sperm motility, reduces fertilization, and causes embryo malformation that in turn affects recruitment and therefore the sustainability of natural populations. The direct molecular effects of UVR are mediated by absorption of certain wavelengths by specific macromolecules and the dissipation of the absorbed energy via photochemical reactions. Most organisms have defense mechanisms that either prevent UVR-induced damage, or mechanisms that repair the damage. Photoprotective pigments, antioxidant defense compounds, and cell cycle development genes are some of the molecules involved in UVR defense. Photoenzymatic repair and nucleotide excision repair are the two primary DNA repair systems in marine ectotherms. We anticipate that toxicogenomic studies will gain importance in UVR research because they can elucidate the primary processes involved in UVR damage and the cellular response to this damage.

  14. Toxicity on aquatic organisms exposed to secondary effluent disinfected with chlorine, peracetic acid, ozone and UV radiation.

    Science.gov (United States)

    da Costa, Juliana Berninger; Rodgher, Suzelei; Daniel, Luiz Antonio; Espíndola, Evaldo Luiz Gaeta

    2014-11-01

    The toxic potential of four disinfectant agents (chlorine, ozone, peracetic acid and UV radiation), used in the disinfection of urban wastewater, was evaluated with respect to four aquatic organisms. Disinfection assays were carried out with wastewater from the city of Araraquara (São Paulo State, Brazil), and subsequently, toxicity bioassays were applied in order to verify possible adverse effects to the cladocerans (Ceriodaphnia silvestrii and Daphnia similis), midge larvae Chironomus xanthus and fish (Danio rerio). Under the experimental conditions tested, all the disinfectants were capable of producing harmful effects on the test organisms, except for C. xanthus. The toxicity of the effluent to C. silvestrii was observed to increase significantly as a result of disinfection using 2.5 mg L(-1) chlorine and 29.9 mg L(-1) ozone. Ozonation and chlorination significantly affected the survival of D. similis and D. rerio, causing mortality of 60 to 100 % in comparison to the non-disinfected effluent. In experiments with effluent treated with peracetic acid (PAA) and UV radiation, a statistically significant decrease in survival was only detected for D. rerio. This investigation suggested that the study of the ideal concentrations of disinfectants is a research need for ecologically safe options for the treatment of wastewater. PMID:25213288

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

    International Nuclear Information System (INIS)

    UV-CD12 at ANKA and its current end-station are described, with a standard module for vacuum-UV synchrotron radiation circular dichroism of bio-macromolecules in the liquid state, and a unique module for macroscopically oriented lipid membranes (oriented circular dichroism). 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

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

    International Nuclear Information System (INIS)

    Plants have evolved adaptations to environmental factors, including solar radiation. In addition to acting as a developmental and physiological signal, UV-B photons also cause cellular damage. Elevated UV-B radiation has pleiotropic effects on plant development, morphology, and physiology, but the regulation of systemic responses is not well-understood. 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. 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 it also has support from RNA profiling: after 1h UV-B, transcripts for myoinositol-1-phosphate synthase, are decreased in both irradiated and shielded leaves suggesting down-regulation of biogenesis. 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. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Bürck, Jochen, E-mail: jochen.buerck@kit.edu; Roth, Siegmar; Windisch, Dirk; Wadhwani, Parvesh; Moss, David [Karlsruhe Institute of Technology (KIT), POB 3640, D-76021 Karlsruhe (Germany); Ulrich, Anne S., E-mail: jochen.buerck@kit.edu [Karlsruhe Institute of Technology (KIT), POB 3640, D-76021 Karlsruhe (Germany); Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, D-76131 Karlsruhe (Germany)

    2015-04-11

    UV-CD12 at ANKA and its current end-station are described, with a standard module for vacuum-UV synchrotron radiation circular dichroism of bio-macromolecules in the liquid state, and a unique module for macroscopically oriented lipid membranes (oriented circular dichroism). 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.

  18. 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. PMID:27341636

  19. Role of DNA damage in local suppression of contact hypersensitivity in mice by UV radiation

    International Nuclear Information System (INIS)

    Exposure of mice to UVE radiation down-regulates the induction of contact hypersensitivity (CHS) responses to haptens applied to the site of irradiation. Concomittantly, the activity of antigen-presenting cells (APC) in the draining lymph nodes is decreased, and T lymphocytes that suppress the induction of CHS are induced. We assessed the role of DNA damage in modulation of the CHS response by UV irradiation by applying liposomes containing T4 endonuclease V (T4N5) to the UV-irradiated skin. Liposomal T4N5, which increases the rate of repair of cyclobutyl pyrimidine dimers (CPD) in DNA, prevented the reduction in the CHS response, the impairment in APC function, and the induction of transferrable immune suppression. Liposomes containing heat-inactivated T4N5 did not restore immune responsiveness. In this model, hapten-bearing APC from unirradiated mice also fail to induce CHS upon injection into UV-irradiated recipients. This systemic effect of UV irradiation on APC function was also prevented by application of liposomes containing active, but not inactive, T4N5. These studies support the hypothesis that DNA damage is an essential initiator of one or more steps leading to impaired immune responsiveness after UV irradiation. They further imply that the release of cytokines that modulate APC function after UV irradiation is triggered by DNA damage. (au) 37 refs

  20. 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.

  1. Effects of increasing UV-B radiation and atmospheric CO2 on photosynthesis and growth: implications for terrestrial ecosystems

    International Nuclear Information System (INIS)

    Increases in UV-B radiation reaching the earth as a result of stratospheric ozone depletion will most likely accompany increases in atmospheric CO2 concentrations. Many studies have examined the effects of each factor independently, but few have evaluated the combined effects of both UV-B radiation and elevated CO2. In general the results of such studies have shown independent effects on growth or seed yield. Although interspecific variation is large, high levels of UV-B radiation tends to reduce plant growth in sensitive species, while CO2 enrichment tends to promote growth in most C3 species. However, most previous studies have not looked at temporal effects or at the relationship between photosynthetic acclimation to CO2 and possible photosynthetic limitations imposed by UV-B radiation. Elevated CO2 may provide some protection against UV-B for some species. In contrast, UV-B radiation may limit the ability to exploit elevated CO2 in other species. Interactions between the effects of CO2 enrichment and UV-B radiation exposure have also been shown for biomass allocation. Effects on both biomass allocation and photosynthetic acclimation may be important to ecosystem structure in terms of seedling establishment, competition and reproductive output. Few studies have evaluated ecosystem processes such as decomposition or nutrient cycling. Interactive effects may be subtle and species specific but should not be ignored in the assessment of the potential impacts of increases in CO2 and UV-B radiation on plants. (author)

  2. Differential flavonoid response to enhanced UV-B radiation in Brassica napus

    International Nuclear Information System (INIS)

    We have examined the qualitative and quantitative differences in methanol-soluble flavonoids of leaves of two cultivars of Brassica napus, which were grown with or without (control) supplemental UV-B radiation. The flavonoids were identified using HPLC-diode array spectroscopy (-DAS), -electrospray ionization-mass spectroscopy (-ESI-MS) and 1H and 13C NMR, and quantitatively analysed by HPLC-DAS. After exposure to supplementary UV-B radiation, the overall amount of soluble flavonoids, kaempferol and quercetin glycosides, increased by ca 150% in cv. Paroll, compared to control plants. Cultivar Stallion showed a 70% increase, and also a lower overall content of soluble flavonoids compared to Paroll. The supplementary UV-B radiation resulted in a marked, specific increase in the amount of quercetin glycosides relative to the kaempferol glycosides with a 36- and 23-fold increase in cvs Paroll and Stallion, respectively. Four of the flavonol glycosides appearing after supplemental UV-B exposure were identified as quercetin- and kaempferol 3-sophoroside-7-glucoside and 3-(2″′-E-sinapoylsophoroside)-7-glucoside. (author)

  3. WHEAT FLOUR HUMIDITY VARIATION WITH UV-VIS RADIATION DOSE REVEALED BY SPECTRAL AND CHEMOMETRIC STUDIES

    Directory of Open Access Journals (Sweden)

    IULIANA MIHAELA LAZĂR

    2012-06-01

    Full Text Available The cells’ exposure to UV radiation induces mutations of the cellular components by its action on DNA, protein synthesis and enzymatic activities. Different varieties of wheat flour were treated with UV-B, UV-A, Vis radiation and compared with untreated samples. The IR spectra for these components were recorded with a Bruker FTIR spectrophotometer using an ATR method, at 4 cm-1 resolution. The paper proposes a comparative study of unmaturing flour behavior under UV-Vis and natural radiations in order to observe the physico-chemical changing by FTIR spectroscopy. At small doses of irradiation (up to 2 h the humidity of the samples decreases and then it significantly increases, most pronounced in Gruia’s case where the humidity is reaching 74.4% of the initial value. Middle infrared spectral studies reveal an inverse weak linear correlation between Amide I region (1650 cm-1 (R-squared value: -0.3168 and an inverse medium linear correlation assigned to area alcohol O-H band at 3290 cm-1 (R-squared value: -0.6064 with the irradiation dose variables. Strong direct linear correlations confirmed by R-squared value: 0.7835 are found between alcohol O-H band at 3290 cm-1 and humidity percentage parameter.

  4. Measurement and evaluation on exposure to UV-radiation at work places

    International Nuclear Information System (INIS)

    The potential risk by being exposed by artificial UV-sources at the workplace in Austria was measured and evaluated. A representative overview of the measurement results, the evaluation of the UV-exposure risk and recommendations to reduction of the risk is given. The international organizations ACGIH and ICNIRP have promulgated guidelines on exposure to ultraviolet radiation (UVR), to protect the general public and workers from hazards which result from being exposed to UVR sources. As the two guidelines differ in some definitions of the exposure duration to calculate the radiant exposure, different results may be obtained. Further it is possible to use the concept of minimal erythema doses - MED's in order to analyze the ability of UV radiation to produce erythema in the human skin. The differences have been analyzed by using the ICNIRP and ACGIH guidelines and the concept of MED's. The different results were compared and discussed. Measurements of UV-radiation concerning photobiological hazards were performed with spectral or integral methods. To increase the accuracy of the measurement a wavelength-dependent correction factor for the integral detectors was used. For simplified handling, the correction factors were classified into different spectra, lamp groups respectively. (author)

  5. Compensation for solar UV damage by solar radiation of longer wavelengths

    International Nuclear Information System (INIS)

    Photobiological experiments and laboratory observations on the egg deposition behaviour of Smittia were undertaken to assess the effect of different spectral ranges of solar radiation on inactivation and photoreactivation of the eggs. The egg deposition of Smittia is not confined to certain periods of the daily cycle, nor are the eggs hidden away even from bright laboratory light. Both the egg shells and the jelly of the clusters absorb UV poorly. An action spectrum was established for inactivation of eggs by exposition to ultraviolet radiation during intravitelline cleavage. It shows a pronounced peak at 295 nm and overlaps with the spectrum of the sunlight between 300 and 310 nm wavelenght. The inactivating range of solar UV was substituted for by 305 nm radiation of 5 nm band width and a dose rate of 0.28 W/m2, obtained from a monochromator. This 'solar UV equivalent' caused inactivation of 50% of exposed eggs within 12 min, whereas exposition to full overhead sunlight produced the same effect only within 3 hrs. It is concluded that the inactivating effect of solar UV (300-310 nm) is counteracted by repair mechanisms requiring light of longer wavelengths (320-480 nm) which are also emitted by the sun. The type of photoreactivation described is difficult to understand within the established framework of nucleic acid repair. However, it seams to play a vital role in the survival of Smittia eggs under sunlight without need for pigmentation or shading. (orig.)

  6. Bactericidal effectiveness of UV radiators, type DRT-400, in a broilerhouse

    International Nuclear Information System (INIS)

    Three UV radiators, type DRT-400, were used in a broilerhouse of BIOS type; 12 lamps in a set, type ZNUV, worked inside of the premises for 5, 8, 12, 16 and 20 min. It was found a high degree reduction of bacteria and fungi in the air, at 60.3 and 74.0% respectively, on the external surface of bedding at 40.3% and 72.2%, and in automatic watering troughs at 44.0 and 97.7% respectively. The degree of microorganisms reduction depended on the time exposition to UV, general air contamination, place of contamination, i.e. bedding or water in troughs. (author)

  7. Duality of solar UV-B radiation and relevant dosimetry: vitamin D synthesis versus skin erythema

    Science.gov (United States)

    Terenetskaya, Irina P.

    2003-06-01

    Solar ultraviolet radiation (UVR) gives rise to beneficial or adverse health effects depending on the dose. Excessive UV exposures are associated with acute and chronic health effect but in appropriate doses UV sunlight is advisable. Important biological function of UVR is initiation of endogenous synthesis of vitamin D in human skin. A useful method based on an in vitro model of vitamin D synthesis ('D-dosimeter') has been specially developed to measure the vitamin D synthetic capacity of sunlight in situ. For the first time laboratory and field tests have been performed to link commonly used erythemal units (MEDs) and previtamin D accumulation.

  8. Response of epidermal blue-green fluorescence emission from Barley leaves to uv radiation stress

    Czech Academy of Sciences Publication Activity Database

    Karlický, Václav; Nezval, J.; Štroch, Michal; Špunda, Vladimír

    Brno: Global change research centre, Academy of Sciences of the Czech Republic, v. v. i, 2013 - (Stojanov, R.; Žalud, Z.; Cudlín, P.; Farda, A.; Urban , O.; Trnka, M.), s. 232-236 ISBN 978-80-904351-8-6. [Global Change and Resilience. Brno (CZ), 22.05.2013-24.05.2013] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA ČR GA522/09/0468 Institutional support: RVO:67179843 Keywords : blue-green fluorescence * UV-B and UV-A radiation * barley * plant stress Subject RIV: EH - Ecology, Behaviour

  9. 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

  10. 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

    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......, 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......, 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 to...

  11. Biological dosimetry to determine the UV radiation climate inside the MIR station and its role in vitamin D biosynthesis

    Science.gov (United States)

    Rettberg, P.; Horneck, G.; Zittermann, A.; Heer, M.

    1998-11-01

    The vitamin D synthesis in the human skin, is absolutely dependent on UVB radiation. Natural UVB from sunlight is normally absent in the closed environment of a space station like MIR. Therefore it was necessary to investigate the UV radiation climate inside the station resulting from different lamps as well as from occasional solar irradiation behind a UV-transparent quartz window. Biofilms, biologically weighting and integrating UV dosimeters successfully applied on Earth (e.g. in Antarctica) and in space (D-2, Biopan I) were used to determine the biological effectiveness of the UV radiation climate at different locations in the space station. Biofilms were also used to determine the personal UV dose of an individual cosmonaut. These UV data were correlated with the concentration of vitamin D in the cosmonaut's blood and the dietary vitamin D intake. The results showed that the UV radiation climate inside the Mir station is not sufficient for an adequate supply of vitamin D, which should therefore be secured either by vitamin D supplementat and/or by the regular exposure to special UV lamps like those in sun-beds. The use of natural solar UV radiation through the quartz window for `sunbathing' is dangerous and should be avoided even for short exposure periods.

  12. Variations in Growth, Photosynthesis and Defense System Among Four Weed Species Under Increased UV-B Radiation

    Institute of Scientific and Technical Information of China (English)

    Shiwen Wang; Liusheng Duan; Anthony Egrinya Eneji; Zhaohu Li

    2007-01-01

    Weed tolerance of UV-B radiation varies with species, and the radiation could affect weed ecology and management.Variations in growth, photosynthesis and defense system among four important agronomic weeds, Abutilon theophrasti Medik, Amaranthus retroflexus L., Digitaria sangulnalis (L.) Scop and Chloris virgata Swartz, under increased UV-B radiation (ambient and increased radiation at 2.7, 5.4 and 10.8 kJ·m-2·d-1) were studied in the greenhouse experiment. After 2 weeks of radiation, the shoots' dry mass decreased with increasing UV-B radiation except for D. sanguinalis. The reduction in biomass was the result of changes in morphology and physiology.Higher levels of UV-B treatment decreased the leaf area, plant height, net photosynthetic rate and chlorophyll contents, while it increased the contents of wax and UV-B absorbing compound in all species, except for A. retroflexus,which did not increase significantly. The activity of superoxide dismutase, catalase, ascorbate peroxide and the content of ascorbic acid changed differently among the weed species as UV-B radiation increased. D. sanguinalis was the most tolerant and A. retroflexus the most sensitive to increased UV-B radiation. The results also show that the two grass species (D. sanguinalis and C. virgata) were more tolerant to UV-B radiation than the two broadleafed species (A. theophrasti and A. retroflexus). The UV-B absorbing compound and leaf wax played important roles against UV-B damages in the two grass weeds. The overall results suggest that weed community, competition and management will be altered by continuous ozone depletion.

  13. Weakening of erythrocyte aggregation and peroxidation of their membrane lipids under UV-radiation

    International Nuclear Information System (INIS)

    A study was made on formation of man crythrocyte piles, induced by dextron and discocyte transformation into spherocytes under the effect of lipid peroxide photoxidation, caused by UV-radiation (integral radiation of SVD-120A mercury lamp), and exogenous product of lipid oxidation-malonic dialdehyde (MDA). The transformation of diskshaped erythrocytes into spherical ones was registered by the decrease of ump of intensity of diffusely reflected light, observed when mixing of erythrocytal suspension was stoped; the formation of erythrocytal piles was registered by the rate of successive decrease of reflected light intensity. Peroxide photooxidation of membrane lipids and their autooxidation, developed in dark after UV-radiation, didn't effect directly on erythrocyte pile formation. Pile formation decreases sufficiently during continuous erythrocyte incubation at 37 deg C after irradiation in result of diskocyte transformation into spherocytes. Exogenous MDA suppresses noticeably (as well as glutaric aldehyde) the formation of erythrocyte piles in their suspension (haemotocryte factor-45%) only at comparatively high concentration (approximately 8x10-4 M) which is not reached during UV-radiation

  14. Long-term effects of elevated UV-B radiation on photosynthesis and ultrastructure of Eriophorum russeolum and Warnstorfia exannulata

    International Nuclear Information System (INIS)

    The depletion of stratospheric ozone above the Arctic regions may increase the amount of UV-B radiation to which the northern ecosystems are exposed. In this paper, we examine the hypothesis that supplemental UV-B radiation may affect the growth rate and photosynthesis of boreal peatland plants and could thereby affect the carbon uptake of these ecosystems. In this study, we report the effects of 3-year exposure to elevated UV-B radiation (46% above ambient) on the photosynthetic performance and ultrastructure of a boreal sedge Eriophorum russeolum and a moss Warnstorfia exannulata. The experiment was conducted on a natural fen ecosystem at Sodankylae in northern Finland. The effects of UV-B radiation on the light response of E. russeolum CO2 assimilation and the maximal photochemical efficiency of photosystem II in a dark-adapted state (Fv/Fm) were measured in the field. In addition, the effect of supplemental UV-B radiation on organelles of photosynthetic cells was studied by electron microscopy. The UV-B treatment had no effect on the CO2 assimilation rate of either species, nor did it affect the structure of the cell organelles. On chlorophyll fluorescence, the UV-B exposure had only a temporary effect during the third exposure year. Our results suggested that in a natural ecosystem, even long-term exposure to reasonably elevated UV-B radiation levels does not affect the photosynthesis of peatland plants. - Research highlights: →Eriophorum russeolum and Warnstorfia exannulata are resistant to UV-B radiationUV-B exposure does not affect the growth or photosynthesis of E. russeolum →Long-term UV-B exposure has no effect on the ultrastructure of E. russeolum

  15. Long-term effects of elevated UV-B radiation on photosynthesis and ultrastructure of Eriophorum russeolum and Warnstorfia exannulata

    Energy Technology Data Exchange (ETDEWEB)

    Haapala, Jaana K., E-mail: jaana.haapala@uef.fi [Department of Biology, University of Eastern Finland, Joensuu Campus, P.O. Box 111, FI-80101 Joensuu (Finland); Moersky, Sami K. [Department of Environmental Science, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, FI-70211 Kuopio (Finland); Saarnio, Sanna [Department of Biology, University of Eastern Finland, Joensuu Campus, P.O. Box 111, FI-80101 Joensuu (Finland); Finnish Environment Institute, Joensuu Office, P.O. Box 111, FI-80101 Joensuu (Finland); Suokanerva, Hanne; Kyroe, Esko [Finnish Meteorological Institute, Sodankylae, Taehtelaentie 62, FI-99600 Sodankylae (Finland); Silvola, Jouko; Holopainen, Toini [Department of Environmental Science, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2010-12-15

    The depletion of stratospheric ozone above the Arctic regions may increase the amount of UV-B radiation to which the northern ecosystems are exposed. In this paper, we examine the hypothesis that supplemental UV-B radiation may affect the growth rate and photosynthesis of boreal peatland plants and could thereby affect the carbon uptake of these ecosystems. In this study, we report the effects of 3-year exposure to elevated UV-B radiation (46% above ambient) on the photosynthetic performance and ultrastructure of a boreal sedge Eriophorum russeolum and a moss Warnstorfia exannulata. The experiment was conducted on a natural fen ecosystem at Sodankylae in northern Finland. The effects of UV-B radiation on the light response of E. russeolum CO{sub 2} assimilation and the maximal photochemical efficiency of photosystem II in a dark-adapted state (F{sub v}/F{sub m}) were measured in the field. In addition, the effect of supplemental UV-B radiation on organelles of photosynthetic cells was studied by electron microscopy. The UV-B treatment had no effect on the CO{sub 2} assimilation rate of either species, nor did it affect the structure of the cell organelles. On chlorophyll fluorescence, the UV-B exposure had only a temporary effect during the third exposure year. Our results suggested that in a natural ecosystem, even long-term exposure to reasonably elevated UV-B radiation levels does not affect the photosynthesis of peatland plants. - Research highlights: {yields}Eriophorum russeolum and Warnstorfia exannulata are resistant to UV-B radiation {yields}UV-B exposure does not affect the growth or photosynthesis of E. russeolum {yields}Long-term UV-B exposure has no effect on the ultrastructure of E. russeolum.

  16. Effect of aerosols on solar UV irradiances during the Photochemical Activity and Solar Ultraviolet Radiation Campaign

    Science.gov (United States)

    Kylling, A.; Bais, A. F.; Blumthaler, M.; Schreder, J.; Zerefos, C. S.; Kosmidis, E.

    1998-10-01

    Surface UV irradiances were measured at two different sites in Greece during June 1996 under noncloudy conditions. The measured UV irradiances are simulated by a radiative transfer model using measured ozone density and aerosol optical depth profiles. The absolute difference between model and measurements ranges between -5% and +5% with little dependence on wavelength. The temporal and solar zenith angle dependence in the difference between model and measurement suggests that part of this difference may be explained by assumptions made about the aerosol single-scattering albedo and phase function. Simulated spectra including aerosols are compared with calculated spectra excluding aerosols. It is found that for otherwise similar atmospheric conditions the UVB irradiance is reduced with respect to aerosol free conditions by 5% to 35% depending on the aerosol optical depth and single-scattering albedo. For the campaign period, changes in the aerosol loading gave larger variations in the surface UV irradiances than the changes seen in the ozone column.

  17. The effect of UV radiation on the thermal degradation of cellulose triacetate

    International Nuclear Information System (INIS)

    The effect of UV radiation on the thermal degradation of cellulose triacetate (CTA) has been investigated. Simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been performed on CTA samples of 0.25 mm thickness. These samples were exposed to different energy fluences of UV in the range 2.3-113 kJ/cm2. The specific heat capacity, Cp, has been evaluated for unexposed and exposed CTA samples using DSC method. The results indicate that the transition temperatures, onset temperatures of evaporation, specific heat capacity and the thermal activation energy of decomposition, Ea are affected by the UV energy fluence owing to the simultaneous processes of degradation and crosslinking

  18. Luminescent emission of LiF: Mg, Ti exposed to UV radiation

    International Nuclear Information System (INIS)

    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)

  19. The influence of increased solar UV-B radiation on magnesium-deficient cowpea seedlings: Changes in the photosynthetic characteristics

    International Nuclear Information System (INIS)

    The influence of increased solar UV-B radiation on the photosynthetic characteristics in cowpea seedlings (Vigna ungniculata) grown at optimal (Mgs) and low (Mgd) Mg levels were studied. Both higher UV-B and Mgd treatments caused significant drops of photochemical activities and net CO2 uptake rates (PN). Yet the UV-B-induced decrease in the photosynthetic efficiency was lesser in Mgd seedlings. The leaf Chl a fluorescence measurements proved that after receiving an enhanced UV-B radiation these seedlings showed a significant enhancement in their variable parts

  20. Changes in UV-B radiation screening effectiveness with leaf age in Rhododendron maximum

    International Nuclear Information System (INIS)

    We examined how ultraviolet-B radiation (UV-B; 300 nm) screening effectiveness changes with leaf age in Rhododendron maximum growing in a shaded understory by measuring depth of penetration and epidermal transmittance with a fibre-optic microprobe. Depth of penetration (and epidermal transmittance) of UV-B decreased with leaf age in 1- to 4-year-old leaves, averaging 62 (32), 52 (22), 45 (16) and 48 μm (13%), respectively. Epidermal thickness increased with age in 1- to 4-year-old leaves due to a thickening of the cuticle from an average of 20 to 29μm. Ultraviolet-B-absorbing compound concentrations increased with age from 1–3 to 1–5 A300 cm−2 leaf area. Concentrations of UV-B-absorbing compounds (area basis) were a strong predictor of depth of penetration (r2 = 0.82) and epidermal transmittance (r2 = 0.95) of UV-B in mature (1–4 year-old) foliage. Chlorophyll concentrations (area basis) increased in leaves up to 3 years of age. Current-year leaves (30 d old) were exceptional in that while they were particularly effective at screening UV-B (depth of penetration and epidermal transmittance averaged 39μm and 5%, respectively) they had relatively low concentrations of UV-B-absorbing compounds (1.3 A300 cm−2). Our findings show that UV-B-screening effectiveness is not necessarily related to absorbing compound concentrations on a whole-leaf basis, possibly due to anatomical changes within the epidermis that occur with leaf age. (author)

  1. Gas sensing properties under UV radiation of In2O3 nanostructures processed by electrospinning

    International Nuclear Information System (INIS)

    Manufacturing In2O3/PVP fibers, by sol–gel method coupled with the electrospinning technique, have been obtained In2O3 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 In2O3 nanostructures after annealing by changing the solvent system utilized for the electrospinning process. The sensing characteristics of the In2O3 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 In2O3 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 In2O3 nanostructures by electrospinning. • Physical and chemical characterization of prepared samples. • Investigation of the sensing properties to monitor NO2 at RT under pulsed UV light

  2. Size variation within monospecific plant canopies under enhanced UV-B radiation

    International Nuclear Information System (INIS)

    Monospecific stands often exhibit distinct size distributions with respect to individual plant size and morphology. Previous work has shown that enhanced ultraviolet-B (UV-B) radiation (280-320 nm; simulating a 20% stratospheric ozone depletion) can change the mean response of individual plants and plant parts within dense monospecific stands of annual dicots and monocots in a glasshouse experiment. Further analysis of the data reveal that individual plant variability may also be altered by UV-B. When analyzed across all (12) species, the coefficient of variation (CV) for fraction of biomass in tillers or branches and leaf length was reduced under enhanced UV-B compared to a no UV-B control. Number of leaves exhibited a decrease in the CV to a lesser degree. No difference in CV was seen for total plant biomass. The results suggest increased solar UV-B associated with ozone depletion has the potential to reduce size variability in plant populations and thus may alter intraspecific competition

  3. Effects of ultraviolet-B radiation (UV-B) on growth and physiology of the dune grassland species Calamagrostis epigeios

    International Nuclear Information System (INIS)

    Seedlings of Calamagrostis epigeios were exposed to four levels of UV-B radiation (280-320 nm), simulating up to 44% reduction of stratospheric ozone concentration during summertime in The Netherlands, to determine the response of this plant species to UV-B irradiation. After six weeks of UV-B treatment, total biomass of all UV-B treated plants was higher, compared to plants that had received no UV-B radiation. The increase of biomass did not appear to be the result of a stimulation of net photosynthesis. Also, transpiration rate and water use efficiency were not altered by UV-B at any exposure level. Pigment analysis of leaf extracts showed no effect of enhanced UV-B radiation on chlorophyll content and accumulation of UV absorbing pigments. UV-B irradiance, however, did reduce the transmittance of visible light (400-700 nm) of intact attached leaves, suggesting a change in anatomical characteristics of the leaves. Additionally, the importance of including an ambient UV-B treatment in indoor experiments is discussed

  4. Effects of UV radiation on the preparation of polypyrrole in the presence of hydrogen peroxide

    Science.gov (United States)

    Zhang, Shihu; Lv, Guowei; Wang, Guolong; Zhu, Kaiming; Yu, Demei; Shao, Jinyou

    2015-10-01

    Conductive polypyrrole was synthesized with hydrogen peroxide (H2O2) as the oxidant. To promote the polymerization of pyrrole, UV radiation was employed. The effects of UV radiation on the preparation of polypyrrole were investigated. The polymerization of pyrrole was conducted with the H2O2 concentration in the range of 0.12-0.96 M and the H2SO4 concentration in the range of 6.8×10-4-0.19 M. The structure characterization indicated that the product polypyrrole was overoxidized partly depending on the concentrations of H2SO4 and H2O2. The increase in H2O2 concentration led to a slight increase in the oxidation and overoxidation of polypyrrole, simultaneously. However, the increase in H2SO4 concentration effectively suppressed the overoxidation of polypyrrole. The morphology, conductivity and thermal stability of the products were also characterized.

  5. UV and X radiation effects on the stability of calcium halide phosphate phosphors. 1

    International Nuclear Information System (INIS)

    Intensity losses of several calcium halide phosphate phosphors have been investigated as a function of the time of irradiation with near UV and X radiation. The results show that antimony-containing foreign phases increase such losses. The directly excited manganese centre emission is much more lowered than the sensitized one. Detrimental effects of the 185 nm UV radiation are observable not only in the first minutes of irradiation but also over considerably extended periods. The sensitization effect caused by irradiation in different gases depends on the phosphor, especially on the content of antimony, and can be explained by the sorption of gaseous impurities at the phosphor surface so that the diffusion of photochemical reaction products from the surface is inhibited

  6. Analysis of a low ozone episode over Extremadura (Spain) in January 2006 and its influence on UV radiation

    Science.gov (United States)

    Antón, M.; Cancillo, M. L.; Serrano, A.; García, J. A.; Acero, F. J.

    2008-04-01

    The main objectives of this work are to analyze, firstly, the detail of the causes of a low ozone event which occurred in January 2006 and, secondly, the related effects of this anomalous episode on ultraviolet (UV) radiation measured at three locations in Extremadura (South-Western Spain). On 19 January 2006, the OMI total ozone column (TOC) was 16-20% below the January mean value of TOMS/NASA TOC (period 1996-2005). The back trajectories analysis with the HYSplit model indicates that the notable decrease of TOC could be attributed to a fast rise of the isentropic trajectories height. Concomitantly, UV erythemal radiation greatly increases (between 23% and 37%) on 19 January 2006 respect to UV erythemal radiation measured on 19 January 2005. This notable increase in winter UV solar radiation may involve harmful effects for organisms adapted to receive less radiation during that season (e.g. early developmental stages of terrestrial plants and phytoplankton).

  7. Effects of Enhanced UV-B Radiation on the Activity and Expression of Alternative Oxidase in Red Kidney Bean Leaves

    Institute of Scientific and Technical Information of China (English)

    Ming-Guang Zhao; Ying-Gao Liu; Li-Xin Zhang; Lin Zheng; Yu-Rong Bi

    2007-01-01

    An increase in ultraviolet (UV) B radiation on the earth's surface is a feature of current global climate changes. It has been reported that alternative oxidase (AOX) may have a protective role against oxidative stress induced by environmental stresses, such as UV-B. To better understand the characteristic tolerance of plants to UV-B radiation, the effects of enhanced UV-B radiation on the activity and expression of AOX in red kidney bean (Phaseolus vulgaris) leaves were investigated in the present study. The results show that the total respiration rate and AOX activity in red kidney bean leaves increased significantly during treatment with enhanced UV-B. However, cytochrome oxidase (COX) activity did not change at 24 h of UV-B treatment, before dropping rapidly. Both alternative pathway content and alternative pathway activity were increased in the presence of exogenous H2O2. Immunoblotting analysis with anti-AOX monoclonal antibody revealed that expression of the AOX protein increased in red kidney bean leaves under enhanced UV-B radiation, reaching a peak at 72increase in AOX activity in red kidney bean leaves under enhanced UV-B radiation was mainly due to H2O2-induced AOX expression.

  8. Sum frequency generation of UV laser radiation at 266  nm in LBO crystal.

    Science.gov (United States)

    Nikitin, D G; Byalkovskiy, O A; Vershinin, O I; Puyu, P V; Tyrtyshnyy, V A

    2016-04-01

    We report experimental results of generation at 266 nm in LBO crystal by frequency mixing of the fundamental (1064 nm) and third harmonic (355 nm) of ytterbium pulsed fiber laser radiation. Deep ultraviolet (DUV) output power of 3.3 W at 266 nm was achieved with 14% IR-to-DUV conversion efficiency. UV-induced bulk degradation of LBO crystals was observed and visualized by the dark field method. PMID:27192312

  9. Impacts of UV radiation on plankton community metabolism along the Humboldt Current System

    OpenAIRE

    Godoy, N.; Canepa, A.; Lasternas, S.; Mayol, E.; Ruíz-Halpern, S.; Agustí, S.; J. C. Castilla; Duarte, C. M.

    2011-01-01

    The Humbolt Current System along the Chilean coast is one of the most productive regions in the world, where UV levels are particularly high due to stratospheric ozone depletion. Research has shown that phytoplankton photosynthesis can be severely inhibited by surface radiation and there are concerns that this will reduce not only algal carbon fixation, but also the carbon supply for higher trophic level. Experimental estimates of community metabolism (NCP, GPP and R) and the impacts o...

  10. Arctic microorganisms respond more to elevated UV-B radiation than CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.; Lee, J.A. [University of Sheffield (United Kingdom). Dept. of Animal and Plant Sciences; Campbell, C.D. [The Macaulay Land Use Research Institute, Aberdeen (United Kingdom); Callaghan, T.V. [Abisko Scientific Research Station, Abisko (Sweden); Gwynn-Jones, D. [University of Wales, Aberystwyth (United Kingdom). Institute of Biological Sciences

    2002-07-01

    Surface ultraviolet-B radiation and atmospheric CO{sub 2} concentrations have increased as a result of ozone depletion and burning of fossil fuels. The effects are likely to be most apparent in polar regions where ozone holes have developed and ecosystems are particularly sensitive to disturbance. Polar plant communities are dependent on nutrient cycling by soil microorganisms, which represent a significant and highly labile portion of soil carbon (C) and nitrogen (N). It was thought that the soil microbial biomass was unlikely to be affected by exposure of their associated plant communities to increased UV-B. In contrast, increasing atmospheric CO{sub 2} concentrations were thought to have a strong effect as a result of greater below-ground C allocation. In addition, there is a growing belief that ozone depletion is of only minor environmental concern because the impacts of UV-B radiation on plant communities are often very subtle. Here we show that 5 years of exposure of a subarctic heath to enhanced UV-B radiation both alone and in combination with elevated CO{sub 2} resulted in significant changes in the C:N ratio and in the bacterial community structure of the soil microbial biomass. (author)

  11. The TPLUS project: a table-top tunable parametric UV radiation source

    International Nuclear Information System (INIS)

    We present the project of a parametric radiation source, the Tunable Parametric Laboratory Ultraviolet Source (TPLUS). We aim at building a prototype of such a source with an electron gun of moderate energy, 100 keV, interacting with a periodic multilayer within a high vacuum experiment chamber. The objective of this table-top facility is to provide users with a cost-effective, simple-handling mean to provide a tunable and intense radiation source in the extreme UV and soft X-ray ranges.

  12. The impact of UV-B radiation and ozone on terrestrial vegetation

    International Nuclear Information System (INIS)

    Although terrestrial vegetation has been exposed to UV-B radiation and ozone over the course of evolutionary history, it is essential to view the effects on vegetation of changing levels of these factors in the context of other features of climate change, such as increasing CO(2) levels and changes in temperature and precipitation patterns. Much of our understanding of the impacts of increased UV-B and ozone levels has come from studies of the effects of each individual factor. While such information may be relevant to a wider understanding of the roles that these factors may play in climate change, experience has shown that the interactions of environmental stresses on vegetation are rarely predictable. A further limitation on the applicability of such information results from the methodologies used for exposing plants to either factor. Much of our information comes from growth chamber, greenhouse or field studies using experimental protocols that made little or no provision for the stochastic nature of the changes in UV-B and ozone levels at the earth's surface, and hence excluded the roles of repair mechanisms. As a result, our knowledge of dose-response relationships under true field conditions is both limited and fragmentary, given the wide range of sensitivities among species and cultivars. Adverse effects of increased levels of either factor on vegetation are qualitatively well established, but the quantitative relationships are far from clear. In both cases, sensitivity varies with stage of plant development. At the population and community levels, differential responses of species to either factor has been shown to result in changes in competitiveness and community structure. At the mechanistic level, ozone generally inhibits photosynthetic gas exchange under both controlled and field conditions, and although UV-B is also inhibitory in some species under controlled conditions, others appear to be indifferent, particularly in the field. Both factors affect

  13. Comparative researches concerning cleaning chosen construction materials surface layer using UV and IR laser radiation

    International Nuclear Information System (INIS)

    The paper presents comparative research studies of cleaning out of deposits and pollution disposals on different constructional materials like; steel, cast iron, aluminium, copper by using UV and IR laser radiation of wavelength λ =1.064 μm; λ = 0.532 μm; λ = 0.355 μm and λ = 0.266 μm and also impulse laser TEA CO2 at radiation λ = 10.6 μm were used for the experiments. Achieved experimental results gave us basic information on parameters and conditions and application of each used radiation wavelength. Each kind of pollution and base material should be individually treated, selecting the length of wave and radiation energy density. Laser microtreatment allows for broad cleaning application of the surface of constructional materials as well as may be used in future during manufacturing processes as: preparation of surface for PVD technology, galvanotechnics, cleaning of the surface of machine parts etc. (author)

  14. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    OpenAIRE

    Tilmes, S.; Kinnison, D. E; Garcia, R. R.; R. Salawitch; Canty, T.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-01-01

    The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UVERY...

  15. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    OpenAIRE

    Tilmes, S.; Kinnison, D. E; Garcia, R. R.; R. Salawitch; Canty, T.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-01-01

    The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UV...

  16. Influence of solar UV radiation on the nitrogen metabolism in needles of Scots pine (Pinus sylvestris L.)

    Energy Technology Data Exchange (ETDEWEB)

    Krywult, Marek [Department of Instrumental Analysis, Provincial Sanitary-Epidemiological Station, State Sanitary Inspection, Pradnicka 76, PL-31-202 Krakow (Poland)], E-mail: marasek2@gazeta.pl; Smykla, Jerzy [Department of Biodiversity, Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, PL-31-120 Krakow (Poland)], E-mail: smykla@iop.krakow.pl; Kinnunen, Heli [Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi (Finland)], E-mail: heli.kinnunen@gmail.com; Martz, Francoise [Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi (Finland)], E-mail: francoise.martz@metla.fi; Sutinen, Marja-Liisa [Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi (Finland); Department of Biology, University of Oulu, P.O. Box 3000, FI-90014 (Finland)], E-mail: marja-liisa.sutinen@metla.fi; Lakkala, Kaisa [Arctic Research Centre, Finnish Meteorological Institute (FMI-ARC), Taehtelaentie 62, FI-99600 Sodankylae (Finland)], E-mail: kaisa.lakkala@fmi.fi; Turunen, Minna [Arctic Centre, University of Lapland, POB 122, FI-96101 Rovaniemi (Finland)], E-mail: minna.turunen@ulapland.fi

    2008-12-15

    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 deg. 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. - This research presents new information on the responses of N metabolism, particularly nitrate reductase (NR) activity, of Scots pine needles to UV radiation and temperature.

  17. Influence of solar UV radiation on the nitrogen metabolism in needles of Scots pine (Pinus sylvestris L.)

    International Nuclear Information System (INIS)

    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 deg. 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. - This research presents new information on the responses of N metabolism, particularly nitrate reductase (NR) activity, of Scots pine needles to UV radiation and temperature

  18. Growth, photosynthesis and UV-B absorbing compounds of Portuguese Barbela wheat exposed to ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Wheat plants (Triticum aestivum L.) were exposed to two levels of UV-B radiation (ambient UV-B and high UV-B, simulating a 20% reduction in the ozone layer) under mediterranean field-growth conditions. After 4 months of UV-B treatment, total plant biomass of high UV-B plants was 18% lower compared to control plants. The decrease of biomass appears to be the result of changes in morphological and physiological processes. High UV-B treatment induces decreases in leaf area, net photosynthesis rate, transpiration rate and water use efficiency. Pigment analysis of leaf extracts showed increases in chlorophyll content and no effect on accumulation of UV-B absorbing pigments. The underlying mechanisms for these results are discussed. (author)

  19. The effect of nucleating agent on radiation stability of polypropylene

    International Nuclear Information System (INIS)

    The radiation stability of polypropylene (PP) with and without nucleating agent (NA) is compared in relation to radiation sterilization of medical devices. In both cases high-and-low-molecular weight PP, the addition of NA increased the transparency and peak crystallization temperature of the PP. On the other hand, in poly(propylene-co-06%ethylene) copolymer, the addition of NA did not improve the transparency but crystallization occurred at higher temperature. Thus, adding NA to PP and copolymer give the advantage of shorter moulding time in the production of medical devices. It is found that both PP and copolymer with NA are less stable during irradiation and during storage after irradiation than without NA, this being the case especially for the lower molecular weight PP. The higher transparency and peak crystallization temperature in the PP and CP with NA were found to be due to smaller spherulites. As the effect of irradiation on polymer, addition of NA induce reduction of radiation stability of polymer owing to the change in morphology. (Author)

  20. 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 Ass

  1. The effect of UV-B radiation on the chlorophyll fluorescence parameters of the husked and the naked oat

    OpenAIRE

    Elżbieta Skórska

    2013-01-01

    Naked oat variety of STH296 showed higher tolerance than traditional variety Bajka on short-term UV-B radiation (UV-BBE=1 1 kJ·m-2) on the stage of primary photosynthesis reaction recorded using chlorophyll fluorescence induction of the leaves.

  2. Photochemical degradation of chromophoric-dissolved organic matter exposed to simulated UV-B and natural solar radiation

    NARCIS (Netherlands)

    Zhang, Y.; Liu, M.; Qin, B.; Feng, S.

    2009-01-01

    Photochemical degradation of chromophoric-dissolved organic matter (CDOM) by UV-B radiation decreases CDOM absorption in the UV region and fluorescence intensity, and alters CDOM composition. CDOM absorption, fluorescence, and the spectral slope indicating the CDOM composition were studied using 0.2

  3. Effects of stratospheric ozone depletion, solar UV radiation, and climate change on biogeochemical cycling: interactions and feedbacks.

    Science.gov (United States)

    Erickson, David J; Sulzberger, Barbara; Zepp, Richard G; Austin, Amy T

    2015-01-01

    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 include: (i) enhanced UV-induced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced mineralisation of photoreactive dissolved organic matter (DOM) in aquatic ecosystems due to changes in continental runoff and ice melting; (iii) reduced efficiency of the biological pump due to UV-induced bleaching of coloured dissolved organic matter (CDOM) in stratified aquatic ecosystems, where CDOM protects phytoplankton from the damaging solar UV-B radiation. Mineralisation of organic matter results in the production and release of CO2, whereas the biological pump is the main biological process for CO2 removal by aquatic ecosystems. This paper also assesses the interactive effects of solar UV radiation and climate change on the biogeochemical cycling of aerosols and trace gases other than CO2, as well as of chemical and biological contaminants. Interacting effects of solar UV radiation and climate change on biogeochemical cycles are particularly pronounced at terrestrial-aquatic interfaces. PMID:25380348

  4. Study of metabolic changes in cornea and lens induced by UV radiation and steroids with mas NMR spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Midelfart, A.; Seather, O.; Risa, O.; Krane, J.; Čejková, Jitka

    Geneva : ogranizator symposia, 2002. s. 47. [International congress of eye research /15./. 06.10.2002-10.10.2002, Geneva] R&D Projects: GA MZd NG16 Keywords : UV radiation Subject RIV: FF - HEENT, Dentistry

  5. Effects of UV-B radiation on a hereditary suture cataract in mice

    International Nuclear Information System (INIS)

    UV-B (290-320 nm, λmax = 305 nm) radiation and the Cat2ns (suture cataract) mutation in mice affect both the anterior lens epithelium and the formation of the suture. A low dose of UV-B radiation (2.2 Jcm-2) induces similar anterior subcapsular and cortical lens opacities in wild type as in heterozygous mutant mice. The UV-B treatment of the mutant lenses, however, leads to an increase in the number of epithelial cell layers in the anterior central part as compared to the wild type indicating a more severe form of the cataract formation in mutants. In addition, mutants demonstrate a predisposition for a rupture of the posterior lens capsule, because from 2.9 Jcm-2 and higher, this phenomenon could always be observed in the UV-B treated mutants, but never in the treated wild type mice. The protein biochemical analyses were performed by gel electrophoresis and isoelectric focusing of extracts of total lenses or from defined areas of the lens (lens slice technique). These covered the patterns of those proteins already synthesized before irradiation, which in irradiated lenses in no case evidenced a difference to the untreated control, neither in the wild type nor in the mutants. In contrast, by analysing specifically those proteins, which are synthesized after irradiation, in both treated groups a protein with a molecular mass of about 31 kDa becomes discernable in both treated groups. In addition, the cataractous lenses demonstrate a significantly enhanced overall synthesis of water-soluble proteins after irradiation, which might promote the rupture of the posterior capsule at the posterior pole. The present study offers for the first time the possibility to discriminate between endogeneous (genetic) effects and exogeneous (environmental) effects in cataractogenesis and to study their interactive effects. The first set of experiments demonstrated a clear intensification of the hereditary cataract by the UV-B treatment. The study supports the hypothesis that

  6. 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

  7. 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.

  8. Control of phenylalanine ammonia-lyase gene promoters from pea by UV radiation

    International Nuclear Information System (INIS)

    The gene fusion system was used to study UV light-control of PS PAL1 and PS PAL2 genes encoding phenylalanine ammonia-lyase of pea. The induction of pea PAL promoters was analysed in transgenic tobacco plants. Binary plasmids (derivatives of pBI101.2 vector) containing 5' regulatory fragments of PS PAL1 and PS PAL2 linked to reporter genes (GUS, LUC) were constructed. The analyses were performed with the use of single constructs (containing one variant of PS PAL promoter and one reporter gene) and dual constructs (containing both PS PAL1 and PS PAL2 promoters connected with different reporter genes). The use of dual constructs enabled the evaluation of both PS PAL promoters activity in the same plant. The analyses of in vitro grown plants have shown that both PAL promoters are strongly induced in leaves subjected to UV radiation. In some cases, the UV-stimulated expression exceeded the exposed areas. This phenomenon was observed more often in the leaves of plants containing the PS PAL1::GUS than PS PAL2::GUS construct. Removal of boxes 2, 4, 5 from PS PAL1 promoter and deletion of its 5' end region (-339 to -1394) decreases the level of gene expression but does not eliminate its responsiveness to UV

  9. Proanthocyanidins from Grape Seeds Inhibit UV Radiation- Induced Immune Suppression in Mice: Detection and Analysis of Molecular and Cellular Targets

    OpenAIRE

    Katiyar, Santosh K.

    2014-01-01

    Ultraviolet (UV) radiation-induced immunosuppression has been linked with the risk of skin carcinogenesis. Approximately, two million new cases of skin cancers, including melanoma and non-melanoma, diagnosed each year in the USA and therefore have a tremendous bad impact on public health. Dietary phytochemicals are promising options for the development of effective strategy for the prevention of photodamaging effects of UV radiation including the risk of skin cancer. Grape seed proanthocyanid...

  10. Phototransformation of membrane lipids and its role in biomembrane function change under the effect of UV-radiation

    International Nuclear Information System (INIS)

    The papers devoted to the investigation of photochemical transformations of lipid under the effect of UV radiation of biological membranes are reviewed. The mechanism of peroxide photooxidation of mebrane lipid is considered. Data on the effect of antioxidants and the structure state of membranes on the process of peroxide photooxidation of lipid are presented. The problem on the role of this process under the effect of UV-radiation on blood and skin of mammals is discussed. 48 refs.; 4 refs

  11. Surface coatings of unsaturated polyester resin Kamper wood (Dry obalan ops spp.) by using UV radiation

    International Nuclear Information System (INIS)

    Kamper wood (Dryobalanops spp.) has high contribution in wood working industry and most of them need surface coating process. Radiation curing of surface coating, especially the use of ultra-violet (UV) light have potential to give contribution in the wood finishing. The experiment on surface coating of kamper wood has been conducted by using UV-radiation. Unsaturated polyester resin with the commercial name of Yucalac type 157 was used as coating materials after being added with styrene monomer, some fillers and radical photoinitiator of 2-hydroxy-2-2-methyl-l- phenyl propanone. Four photoinitiator concentration levels of 1.5 ; 2 ; 2.5 and 3 % by weight of resin were used. The coating materials were coated onto the wood panel samples by using high pressure sprayer. The wood samples were then exposed to irradiation by using 80 Watts/cm UV-source with variable conveyor speed of 3 ; 4 ; 5 and 5.8 m/min. Formulation of coating materials, pendulum hardness, adhesion, and gloss of cured films were evaluated

  12. Effect of UV-radiation on track etch parameters of CR-39 plastic track detectors

    International Nuclear Information System (INIS)

    CR-39 track detectors have been irradiated with 239Pu source at nuclear physics laboratory B.H.U. Varanasi, to investigate the track recording properties of the detector. The bulk etch rate is determined by measuring the change in thickness before and after etching, and track etch rate is determined by measuring the change in track length. Other track parameters such as diameter and sensitivity of the plastic detector are also determined. Another set of CR-39 plastic detector is irradiated by 239Pu source and exposed by UV-radiation after irradiation to see the effect of UV-rays on track etches parameters. All detectors were etched in 6.25 N NaOH solution at different temperatures for different hours and all track parameters are measured by optical microscope (Olympus BH-2, magnification 600x). After etching in 6.25 N NaOH solution we see that bulk etch rate, track etch rate and track diameter increased in the case of UV-radiation exposed CR-39 plastics detectors. (author)

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

    Directory of Open Access Journals (Sweden)

    J. Kujanpää

    2015-05-01

    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. The input total ozone product is generated by the German Aerospace Center (DLR also within the O3M SAF framework. Polar orbiting satellites provide global coverage but infrequent sampling of the diurnal cloud cover. The diurnal variation of the surface UV radiation is extremely strong due to modulation by solar elevation and rapidly changing cloud cover. At the minimum, one sample of the cloud cover in the morning and another in the afternoon are needed to derive daily maximum and daily integrated surface UV radiation quantities. This is achieved 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 (daytime descending node around 09:30 LT and Polar Orbiting Environmental Satellites (POES of the National Oceanic and Atmospheric Administration (NOAA in the afternoon orbit (daytime ascending node around 14:30 LT. 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 using commercial telecommunication satellites for broadcasting the data to the user community. The surface UV product includes daily maximum dose rates and integrated daily doses with different biological weighting functions, integrated UVB and UVA radiation, solar noon UV Index and daily maximum photolysis

  14. Divergence in DNA photorepair efficiency among genotypes from contrasting UV radiation environments in nature.

    Science.gov (United States)

    Miner, Brooks E; Kulling, Paige M; Beer, Karlyn D; Kerr, Benjamin

    2015-12-01

    Populations of organisms routinely face abiotic selection pressures, and a central goal of evolutionary biology is to understand the mechanistic underpinnings of adaptive phenotypes. Ultraviolet radiation (UVR) is one of earth's most pervasive environmental stressors, potentially damaging DNA in any organism exposed to solar radiation. We explored mechanisms underlying differential survival following UVR exposure in genotypes of the water flea Daphnia melanica derived from natural ponds of differing UVR intensity. The UVR tolerance of a D. melanica genotype from a high-UVR habitat depended on the presence of visible and UV-A light wavelengths necessary for photoenzymatic repair of DNA damage, a repair pathway widely shared across the tree of life. We then measured the acquisition and repair of cyclobutane pyrimidine dimers, the primary form of UVR-caused DNA damage, in D. melanica DNA following experimental UVR exposure. We demonstrate that genotypes from high-UVR habitats repair DNA damage faster than genotypes from low-UVR habitats in the presence of visible and UV-A radiation necessary for photoenzymatic repair, but not in dark treatments. Because differences in repair rate only occurred in the presence of visible and UV-A radiation, we conclude that differing rates of DNA repair, and therefore differential UVR tolerance, are a consequence of variation in photoenzymatic repair efficiency. We then rule out a simple gene expression hypothesis for the molecular basis of differing repair efficiency, as expression of the CPD photolyase gene photorepair did not differ among D. melanica lineages, in both the presence and absence of UVR. PMID:26547143

  15. Elevated UV-B radiation incident on Quercus robur leaf canopies enhances decomposition of resulting leaf litter in soil

    International Nuclear Information System (INIS)

    We examined whether the exposure of Quercus robur L. to elevated UV-B radiation (280–315 nm) during growth would influence leaf decomposition rate through effects on litter quality. Saplings were exposed for eight months at an outdoor facility in the UK to a 30% elevation above the ambient level of erythemally weighted UV-B radiation under UV-B treatment arrays of fluorescent lamps filtered with cellulose diacetate, which transmitted both UV-B and UV-A (315–400 nm) radiation. Saplings were exposed to elevated UV-A alone under control arrays of lamps filtered with polyester and to ambient radiation under unenergised arrays of lamps. Abscised leaves from saplings were enclosed in 1 mm2 mesh nylon bags, placed in a Quercus–Fraxinus woodland and were sampled at 0.11, 0.53, 1.10 and 1.33 years for dry weight loss, chemical composition and saprotrophic fungal colonization. At abscission, litters from UV-A control arrays had ≈ 7.5% higher lignin/nitrogen ratios than those from UV-B treatment and ambient arrays (P < 0.06). Dry weight loss of leaves treated with elevated UV-B radiation during growth was 2.5% and 5% greater than that of leaves from UV-A control arrays at 0.53 and 1.33 years, respectively. Litter samples from UV-B treatment arrays lost more nitrogen and phosphorus than samples from ambient arrays and more carbon than samples from UV-A control arrays. The annual fractional weight loss of litter from UV-B treatment arrays was 8% and 6% greater than that of litter from UV-A control and ambient arrays, respectively. Regression analyses indicated that the increased decomposition rate of UV-B treated litters was associated with enhanced colonization of leaves by basidiomycete fungi, the most active members of the soil fungal community, and that the frequency of these fungi was negatively associated with the initial lignin/nitrogen ratio of leaves. (author)

  16. 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.

  17. Elevated UV-B radiation increased the decomposition of Cinnamomum camphora and Cyclobalanopsis glauca leaf litter in subtropical China

    Energy Technology Data Exchange (ETDEWEB)

    Song, Xinzhang Z.; Zhang, Huiling L.; Jiang, Hong; Yu, Shuquan Q. [Zhejiang Agriculture and Forestry Univ., Lin' an (China). The Nurturing Station for the State Key Lab. of Subtropical Silviculture; Zhejiang Agriculture and Forestry Univ., Lin' an (China). Zhejiang Provincial Key Lab. of Carbon Cycling and Carbon Sequestration in Forest Ecosystems; Chang, Scott X. [Alberta Univ., Edmonton (Canada). Dept. of Renewable Resources; Peng, Changhui H. [Quebec Univ., Montreal (Canada). Inst. of Environment Sciences

    2012-03-15

    Ultraviolet-B (UV-B) radiation reaching the earth's surface has been increasing due to ozone depletion and can profoundly influence litter decomposition and nutrient cycling in terrestrial ecosystems. The role of UV-B radiation in litter decomposition in humid environments is poorly understood; we thus investigated the effect of UV-B radiation on litter decomposition and nitrogen (N) release in a humid subtropical ecosystem in China. We conducted a field-based experiment using the litterbag method to study litter decomposition and N release under ambient and elevated (31% above ambient) UV-B radiation, using the leaf litter of two common tree species, Cinnamomum camphora and Cyclobalanopsis glauca, native to subtropical China. Elevated UV-B radiation significantly increased the decomposition rate of C. camphora and C. glauca leaf litter by 16.7% and 27.8%, respectively, and increased the N release from the decomposing litter of C. glauca but not C. camphora. Elevated UV-B radiation significantly accelerated the decomposition of litter of two native tree species and the N release from the decomposition litter of C. glauca in humid subtropical China, which has implications for soil carbon flux and forest productivity. (orig.)

  18. Effect of long-wave UV radiation on mouse melanoma: an in vitro and in vivo study

    OpenAIRE

    Pastila, Riikka

    2006-01-01

    The skin cancer incidence has increased substantially over the past decades and the role of ultraviolet (UV) radiation in the etiology of skin cancer is well established. Ultraviolet B radiation (280-320 nm) is commonly considered as the more harmful part of the UV-spectrum due to its DNA-damaging potential and well-known carcinogenic effects. Ultraviolet A radiation (320-400 nm) is still regarded as a relatively low health hazard. However, UVA radiation is the predominant component in sunlig...

  19. Prophylactic UV Radiation and CIE Standard on Photobiological Safety of Lamps and Lamp Systems

    Science.gov (United States)

    Sarychev, Genrih; Gavrilkina, Galina

    Two aspects of UV photobiology have come up almost simultaneously for discussion. On the one hand, the CIE has, for all practical purposes, completed discussions of a new standard “CIE S 009/E: 2002 Photobiological Safety of Lamps and Lamp Systems”1), and it was adopted without any amendments. On the other hand, some national standards (for example, in Russia) have for decades insisted on UVA+UVB radiation being used for prophylactic purposes at actinic erythemal doses (around 140 J m-2 per 8 hours of irradiation), which are significantly higher than prohibitive doses of actinic UV hazard (30 J m-2) suggested in the CIE standard. It seems that this arisen situation is to be thought about more carefully.

  20. Impacts of UV radiation on plankton community metabolism along the Humboldt Current System

    Science.gov (United States)

    Godoy, N.; Canepa, A.; Lasternas, S.; Mayol, E.; Ruíz-Halpern, S.; Agustí, S.; Castilla, J. C.; Duarte, C. M.

    2011-06-01

    The Humbolt Current System along the Chilean coast is one of the most productive regions in the world, where UV levels are particularly high due to stratospheric ozone depletion. Research has shown that phytoplankton photosynthesis can be severely inhibited by surface radiation and there are concerns that this will reduce not only algal carbon fixation, but also the carbon supply for higher trophic level. Experimental estimates of community metabolism (NCP, GPP and R) and the impacts of UV on community metabolism were assessed at 8 stations along the meridional track by the Humbold-2009 cruise (54.80° S-23.85° S) on board RV Hespérides from 5 to 15 March 2009. The results showed an increase UVB penetration towards the Equator, along the Humboldt Current System, suggesting a more important impact of UVB radiation towards the north. The metabolic rates observed were within average values reported for the Ocean Pacific and did not show the water mass investigated to be exceptionally productive at the time of the study. Experimental evaluation of the effect of UVB radiation on surface waters, those most strongly affected by UVB, showed that UVB radiation suppressed net community production, resulting in a dominance of heterotrophic communities in surface waters, compared to the prevalence of autotrophic communities inferred when materials, excluding UVB radiation, are used for incubation. These results show that UVB radiation, which has increased greatly in the study area, may have suppressed net community production of the plankton communities, possibly driving plankton communities in the Southwest Pacific towards CO2 sources.

  1. Impacts of UV radiation on plankton community metabolism along the Humboldt Current System

    Directory of Open Access Journals (Sweden)

    N. Godoy

    2011-06-01

    Full Text Available The Humbolt Current System along the Chilean coast is one of the most productive regions in the world, where UV levels are particularly high due to stratospheric ozone depletion. Research has shown that phytoplankton photosynthesis can be severely inhibited by surface radiation and there are concerns that this will reduce not only algal carbon fixation, but also the carbon supply for higher trophic level. Experimental estimates of community metabolism (NCP, GPP and R and the impacts of UV on community metabolism were assessed at 8 stations along the meridional track by the Humbold-2009 cruise (54.80° S–23.85° S on board RV Hespérides from 5 to 15 March 2009. The results showed an increase UVB penetration towards the Equator, along the Humboldt Current System, suggesting a more important impact of UVB radiation towards the north. The metabolic rates observed were within average values reported for the Ocean Pacific and did not show the water mass investigated to be exceptionally productive at the time of the study. Experimental evaluation of the effect of UVB radiation on surface waters, those most strongly affected by UVB, showed that UVB radiation suppressed net community production, resulting in a dominance of heterotrophic communities in surface waters, compared to the prevalence of autotrophic communities inferred when materials, excluding UVB radiation, are used for incubation. These results show that UVB radiation, which has increased greatly in the study area, may have suppressed net community production of the plankton communities, possibly driving plankton communities in the Southwest Pacific towards CO2 sources.

  2. Multilevel UV-B Attenuance : Morphological and Chemical Adaptations of Vicia faba to Ultraviolet-B Radiation

    OpenAIRE

    Meijkamp, B.B.

    2006-01-01

    Due to anthropogenic reduction of stratospheric ozone, levels of potentially harmful solar UV-B radiation (280-315 nm) have been increasing on earth during the last three decades. The main aim of this thesis was to study growth responses and morphological and chemical adaptation mechanisms to harmful UV-B radiation. Two cultivars of Vicia faba, differing in UV-B sensitivity were used as a model system. Constitutive defence mechanisms appeared to function very well; even in the sensitive cv. P...

  3. 拟南芥芥子酸酯对UV-B辐射的响应%Response of sinapate esters in Arabidopsis thaliana to UV-B radiation

    Institute of Scientific and Technical Information of China (English)

    李敏; 王垠; 牟晓飞; 王洋; 阎秀峰

    2012-01-01

    芥子酸酯(sinapate esters)是拟南芥和其他十字花科植物中大量存在的一类具有紫外吸收作用的羟基肉桂酸衍生物,有研究表明其紫外吸收能力甚至强于类黄酮.以模式植物拟南芥(Arabidopsis thaliana)为实验材料,通过施加低强度(40 μW/cm2)、相对长时间(7 d)的UV-B辐射,考察了拟南芥幼苗和成苗芥子酸酯组分(芥子酰葡萄糖、芥子酰苹果酸)和含量及合成途径关键酶编码基因表达水平对UV-B辐射的响应.经过7d的UV-B辐射处理,拟南芥幼苗和成苗的芥子酰葡萄糖、芥子酰苹果酸含量均高于对照植株,芥子酸酯表现为响应UV-B辐射而积累.无论是幼苗还是成苗,叶片中芥子酰苹果酸的含量都要比芥子酰葡萄糖高出一个数量级,而且在UV-B处理过程中观察到芥子酰葡萄糖含量减少而芥子酰苹果酸含量增加,催化芥子酰葡萄糖生成芥子酰苹果酸的芥子酰葡萄糖苹果酸转移酶编码基因的表达水平也显著提高,说明芥子酰苹果酸在拟南芥叶片响应UV-B辐射过程中起重要作用并优先合成.另外,拟南芥幼苗中两种芥子酸酯的含量是成苗中的数十倍之多,芥子酸酯合成途径关键酶编码基因fah1和sng1的相对表达量也显著高于成苗.同时,在响应UV-B辐射的过程中,幼苗中芥子酰葡萄糖、芥子酰苹果酸含量的变化幅度(分别是7.01%、6.05%)远远低于成苗叶片中芥子酰葡萄糖、芥子酰苹果酸含量的变化幅度(分别是21.88%、70.63%),这可能意味着拟南芥叶片中芥子酸酯对于UV-B辐射的防护作用,幼苗属于组成型防御(constitutive defense),而到成苗则转变为诱导型防御(inducible defense).%The impact of UV-B radiation (280 to 320 nm) at the earth's surface is predicted to increase because of the anthropogenic depletion of stratospheric ozone caused by industrial emissions of atmospheric pollutants. Plant growth and productivity are compromised

  4. Investigating microbial diversity and UV radiation impact at the high-altitude Lake Aguas Calientes, Chile

    Science.gov (United States)

    Escudero, Lorena; Chong, Guillermo; Demergasso, Cecilia; Farías, María Eugenia; Cabrol, Nathalie A.; Grin, Edmond; Minkley, Edwin, Jr.; Yu, Yeoungeob

    2007-09-01

    The High-Lakes Project is funded by the NAI and explores the highest perennial volcanic lakes on Earth in the Bolivian and Chilean Andes, including several lakes ~6,000 m elevation. These lakes represent an opportunity to study the evolution of microbial organisms in relatively shallow waters not providing substantial protection against UV radiation. Aguas Calientes (5,870 m) was investigated (November 2006) and samples of water and sediment collected at 1, 3, 5, and 10 cm depth. An Eldonet UV dosimeter positioned on the shore records UV radiation and temperature, and is logging data year round. A UV SolarLight sensor allowed acquisition of point measurements in all channels at the time of the sampling. UVA, UVB, and PAR peaks between 11:00 am and 1:00 pm reached 7.7 mW/cm2, 48.5 μW/cm2, and 511 W/m2, respectively. The chemical composition of the water sample was analyzed. DNA was extracted and DGGE analyses with bacterial and archaeal 16S fragments were performed to describe microbial diversity. Antibiotic resistances were established previously in similar environments in Argentine Andean wetlands. In order to determine these resistances in our samples, they were inoculated onto LB and R2A media and onto R2A medium containing either chloramphenicol, ampicillin or tetracycline. Bacterial was higher than archeal cell number determined by RT-PCR in all the samples, reaching maximum total values of 5x10 5 cell mL-1. DGGE results from these samples and Licancabur summit lake (5,916 m) samples were also compared. Eight antibiotic-resistant Gram negative strains have been isolated with distinct resistance patterns.

  5. 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. PMID:25113622

  6. UV-radiation in the past: Reconstruction and long-term changes in Austria

    Science.gov (United States)

    Hadzimustafic, J.; Simic, S.; Fitzka, M.

    2013-05-01

    Series of daily erythemal UV-dose are reconstructed for the last 30 years of the 20th century in Austria and its changes during that period with respect to observed changes in total ozone and cloud cover discussed. The reconstruction method is based on the relationship between long-term global radiation and sunshine duration records and existing measurements of erythemal UV at several locations. Through comparison with different data sources efforts are made to assure high data quality for all input parameters. The results for reconstructed daily sums show high correlations (0.95-0.99) with observed values compared on a yearly and seasonal basis throughout the overlapping period 1998-2010. Assessed from the reconstructed data, long-term variability of erythemal UV daily dose for two time periods has been quantified (1977-1995, 1996-2010). Special emphasis is put on the investigation of changes in UV due to observed trends in clouds and sunshine duration in the Austrian Alpine regions during the last decades. The earlier period shows significant changes between +4.1 %/dec and +6.9 %/dec at six stations in Austria, mainly due to significant decreases in total ozone column of up to -3.7 %/dec. Positive significant trends of around +2%/dec are found in cloud and aerosol modification factors at most of stations along with observed positive trends in sunshine duration, being statistically significant at eastern and southern stations. In spite of ozone layer recovery since the mid 1990s, the latter period does not reveal any statistically significant changes in erythemal UV irradiation.

  7. Comparison of radiation dosimetry for several potential myocardial imaging agents

    International Nuclear Information System (INIS)

    Although myocardial imaging is currently dominated by Tl-201, several alternative agents with improved physiologic or radionuclidic properties have been proposed. Based on human and animal studies in the literature, the metabolism of several of these compounds was studied for the purpose of generating radiation dose estimates. Dose estimates are listed for several I-123-labeled free fatty acids, an I-123-labeled phosphonium compound, Rb-82, Cu-64, F-18 FDG (all compounds which are taken up by the normal myocardium), and for Tc-99m pyrophosphate (PYP) (which localizes in myocardial infarcts). Dose estimates could not be generated for C-11 palmitate, but his compound was included in a comparison of myocardial retention times. For the I-123-labeled compounds, I-124 was included as a contaminant in generating the dose estimates. Radiation doses were lowest for Rb-82 (gonads 0.3-0.4 Gy/MBq, kidneys 8.6 Gy/MBq). Doses for the I-123-labeled fatty acids were similar to one another, with IPPA being the lowest (gonads 15 Gy/MBq, heart wall 18 Gy/MBq). Doses for Tc-99m PYP were also low (gonads 4-7 Gy/MBq, heart wall 4 Gy/MBq, skeleton 15 Gy/MBq). The desirability of these compounds is discussed briefly, considering half-life, imaging mode and energy, and dosimetry, including a comparison of the effective whole body dose equivalents. 37 references, 11 tables

  8. Susceptibility of zoospores to UV radiation determines upper depth distribution limit of Arctic kelps: evidence through field experiments

    OpenAIRE

    Wiencke, Christian; Roleda, Michael; Gruber, A.; Clayton, M. N.; Bischof, Kai

    2006-01-01

    1. The UV susceptibility of zoospores of the brown seaweeds Saccorhiza dermato- dea, Alaria esculenta and Laminaria digitata (Laminariales) was determined in field experiments in June 2004 on Spitsbergen (78° 55' N, 11° 56' E).2. Freshly released zoospores were exposed for one or two days at various water depths to ambient solar radiation, ambient solar radiation depleted of UVB radiation (UVBR) and ambient solar radiation depleted of both UVBR and UVAR. Subsequently, germination rates were d...

  9. Changes in growth and pigment concentrations with leaf age in pea under modulated UV-B radiation field treatments

    International Nuclear Information System (INIS)

    We assessed whether growth of garden pea (Pisum sativum mutant Argenteum) was reduced under ecologically relevant enhancements of ultraviolet-B radiation (UV-B, 280–320 nm) by employing modulated field lampbanks which simulated 0, 16 or 24% ozone depiction. In addition, we determined whether enhanced UV-B altered the concentration and distribution of chlorophyll and UV-B-absorbing compounds in leaves, and whether this was dependent on leaf age. There were no significant UV-B effects on the four whole-plant parameters we examined (height, above-ground biomass, total leaflet area or average leaflet area). Of the 12 leaf-level parameters we examined, UV-B had a significant effect (P < 0.05) on only one parameter: the ratio of UV-B-absorbing compounds to chlorophyll, which was greatest at the highest UV-B level. Total chlorophyll concentrations tended to be lower under enhanced UV-B (P= 0.11), while the proportion of UV-B-absorbing compounds in the adaxial epidermis tended to be higher (P= 0.11). Total leaf concentrations of UV-B-absorbing compounds were unaffected by UV-B level. Cooler, suboptimal growing conditions during this late summer/early autumn experiment may have masked some potential UV-B effects. In contrast to the UV-B effects, we found strong leaf-age effects on nearly all parameters that we assessed. On an area basis, concentrations of total chlorophyll and UV-B-absorbing compounds increased with leaf age, while Chlorophyll a/b) ratios decreased. One of the few parameters unaffected by leaf age was the ratio of UV-B-absorbing compounds to total chlorophyll, which remained constant within a given UV-B treatment. Pea was much less sensitive to enhanced UV-B than in previous growth-chamber and greenhouse studies, and in nearly all cases UV-B treatment effects were overshadowed by leaf-age effects. In view of the large effect leaf age had on concentrations of UV-B-absorbing compounds, as well as their distribution within leaves, researchers may need to

  10. UV radiation-induced photochemical damage of tryptophan in peptides, proteins and ocular lenses

    International Nuclear Information System (INIS)

    These studies were undertaken to investigate the possible involvement of the amino acid tryptophan in the near-ultraviolet radiation-induced photochemical alteration of peptides and proteins and the role tryptophan photolysis plays in ocular lens damage. Sample irradiations were performed to determine if tryptophan photolysis occurs with radiation in the UV-A region in comparison to photolysis induced by wavelengths in the normal absorption band of the amino acid (UV-B). Photolysis studies were carried out on free tryptophan and two dipeptides, tryptophyglycine and glycyltryptophan, in aqueous solutions at different pH values in the range 4.5-10.0 under aerated or anaerobic conditions. Rates of photolysis of these 290 nm-irradiated compounds, detected by observing tryptophan fluorescence intensity loss during irradiation, were compared and significant differences were observed for each compound which varied with pH and oxygen environment. Another series of experiments examined the photolysis of tryptophan residues in lens proteins in whole rat lenses induced by 290 nm and 298 nm dye laser radiation. Tryptophan residue photolysis was, once again, monitored by loss in tryptophan fluorescence intensity. A relationship was derived between tryptophan loss and photoproduct buildup during irradiation

  11. UV radiation, elevated CO2 and water stress effect on growth and photosynthetic characteristics in durum wheat

    International Nuclear Information System (INIS)

    The objective of this research was to investigate the changes in photosynthetic pigments and other physiological and biochemical traits of durum wheat exposed to ultraviolet A, B and C radiation, elevated CO2 and water stress. The results showed that carotenoids, anthocyanins, flavonoids and proline content increased significantly by decreasing ultraviolet wavelength. Elevated CO2 increased only height and specific leaf area. Water stress induced a significant increase in carotenoids, anthocyanins, flavonoids, proline and protein content. Interaction of UV-C and water stress in ambient CO2 increased UV screen pigments and proline content, while under elevated CO2 these increments were alleviated. Interaction among UV-C radiation, elevated CO2 and water stress demonstrated a significant decrease in Fv/Fm, chlorophyll, protein, carbohydrates and specific leaf area compared to control. The results of this experiment illustrate that increased UV radiation and water stress induces an increase of screen pigments and elevated CO2 prevents accumulation of these pigments

  12. Thermoluminescence response induced by UV radiation in Eu-doped zirconia nanopowders

    International Nuclear Information System (INIS)

    Eu-doped zirconia nanopowders were prepared by the sol–gel method. A detailed examination of the morphology and crystalline characterisation was performed through scanning and transmission electron microscopy and X-ray diffraction. Analysis of the thermoluminescent (TL) properties of the ZrO2 doped with Eu and exposed to UV radiation was also conducted. The characterisation results show an appreciable influence of the Eu-dopant on particle sizes and the zirconia crystalline phases; at lower concentration of Eu, tetragonal ZrO2 is the most abundant phase whereas a concentration up to 2.0 wt% of Eu leads to the formation of the monoclinic phase. However, if the proportion of Eu increases to 4.0 wt%, the presence of monoclinic ZrO2 diminishes. Monoclinic ZrO2 is responsible for trapping and recombination mechanisms. Nevertheless, depending on the concentration of Eu(III), different glow curves are induced by UV radiation on ZrO2:Eu. A better thermoluminescence response was observed for ZrO2:Eu (1.0 wt%) sample, in which only one narrow glow peak centred at 130 °C with almost two times intensity of pure ZrO2 was observed. - Highlights: • Presence of Eu induces growth of the particle size of ZrO2. • ZrO2:Eu showed good dose response to UV radiation. • The addition of Eu improved the thermoluminescent intensity of about two times. • Monoclinic ZrO2 is responsible for the presence of trapping and recombination mechanisms that induced the main thermoluminescent signal. • Kinetic parameters for pure and doped zirconia have been calculated by deconvolution technique

  13. Effects of enhanced UV-B radiation on plant chemistry: nutritional consequences for a specialist and generalist lagomorph.

    Science.gov (United States)

    Thines, Nicole J; Shipley, Lisa A; Bassman, John H; Fellman, John K; Mattison, D Scott; Slusser, James R; Gao, Wei

    2007-05-01

    Ultraviolet-B (UV-B) radiation has been increasing in temperate latitudes in recent decades and is expected to continue rising for some time. Enhanced UV-B radiation can change plant chemistry, yet the effects of these changes on mammalian herbivores are unknown. To examine the influence of enhanced UV-B radiation on nutrition of a specialist and generalist hindgut fermenter, we measured nutritional and chemical constituents of three common North American range plants, big sagebrush (Artemisia tridentata), yarrow (Achillea millefolium), and bluebunch wheatgrass (Pseudoregneria spicata), and how these changes influenced in vitro dry matter digestibility and in vivo digestibility by pygmy rabbits (Brachylagus idahoensis) and eastern cottontails (Sylvilagus floridanus). Forages were irradiated for 3 mo with ambient (1x) or supplemental (1.6x) UV-B radiation representing a 15% ozone depletion for Pullman, WA, USA. Enhanced UV-B radiation had minimal effects on the nutritional content and the tannin-binding capacity of forages. Similarly, the terpene concentration in sagebrush and yarrow was not affected by higher UV-B irradiances. Flavonoid compounds increased in sagebrush but decreased in yarrow. Rabbit preference and intake was not affected by treatment levels for any forage species and no differences were found between treatments for dry matter, fiber, protein digestibility, and apparent digestible energy. PMID:17406969

  14. Dynamics of anthocyanin in aging of ipomea purpurea flowers treated by uv-b radiation

    OpenAIRE

    Анастасія Миколаївна Берестяна

    2014-01-01

    The dynamics of the anthocyanin content reduction in the course of aging of the Ipomoea purpureа petals, which characterizes the rate of the degradation processes in a cell, has been studied. The analysis included the impact of various UV-B radiation doses on the rate of anthocyanin age-related decomposition. The experiment proved that but one dose – 12.6 kJ/m2 contributed to the deceleration of the anthocyanin decomposition rate, within the range studied. The probable mechanisms that connect...

  15. Dynamics of anthocyanin in aging of ipomea purpurea flowers treated by uv-b radiation

    Directory of Open Access Journals (Sweden)

    Анастасія Миколаївна Берестяна

    2014-10-01

    Full Text Available The dynamics of the anthocyanin content reduction in the course of aging of the Ipomoea purpureа petals, which characterizes the rate of the degradation processes in a cell, has been studied. The analysis included the impact of various UV-B radiation doses on the rate of anthocyanin age-related decomposition. The experiment proved that but one dose – 12.6 kJ/m2 contributed to the deceleration of the anthocyanin decomposition rate, within the range studied. The probable mechanisms that connect ageing and pigment degradation are being discussed. 

  16. Different responses to UV-B enhanced solar radiation in radish and carrot

    International Nuclear Information System (INIS)

    Radish (Raphanus sativus L.) and carrot (Daucus carota L.), plants with underground storage organs grown in the field, were exposed to either ambient (UVA) or 20 % UV-B (UVE) enhanced solar radiation till their root yield stage. In radish, UVE produced a significant increase in shoot and root fresh mass (FM), increase in the contents of chlorophyll, carotenoids, flavonoids, and total proteins per unit FM, Hill reaction rate, and root yield. In contrast, carrot responded negatively to UVE showing a loss in the above parameters. (author)

  17. Influences of different UV-B radiation treatments in short time on some physiological characteristics of winter wheat seedlings

    International Nuclear Information System (INIS)

    [Objective] studying the influences of different UV-B radiation treatments in short time on some physiological characteristics of winter wheat seedlings was to provide reference for the mechanism of plant response to ultraviolet irradiation in short time. [Method] The winter wheat taken as materials were treated with 15 and 30μW/cm2 UV-B radiation, then the physiological indexes such as pigment content and photosynthetic rate were determined. [Results] The UV-B treatment caused the declines of chlorophyll content, soluble protein content and water content of leaves, besides, dose-effect was existed. The decline of 30 μW/cm2 treatment was bigger than that of 15 μW/cm2 treatment. The influences of UV-B radiation on carotenoid content and anthocyanidin content were similar; the change trends were declined firstly then increased. The UV-B treatment with two doses restrained the electron transport of PSⅡ, particularly; the inhibitory effect was biggest after treated 2h, and then this effect was declined in 4, 6 and 8h, so the dose-effect was existed. The UV-B radiation with two doses restricted photosynthetic rate and the inhibitory effect increased with the increase of treatment time. The high dose treatment caused huge damage to membrane system, while the result of low dose treatment was not obvious. [Conclusion] UV-B radiation treatment had dose-effect on winter wheat seedlings in short time and the influence of high dose was bigger than that of low dose. With the increase of treatment time, the damage was alleviated; besides, the result was not similar to that of UV-B radiation in long time

  18. Effects of ion beams pretreatment on damage of UV-B radiation on seedlings of winter wheat (Triticum aestivum L.).

    Science.gov (United States)

    Zhao, Shuaipeng; Huang, Qunce; Yang, Pengming; Zhang, Jiajia; Jia, Hongru; Jiao, Zhen

    2012-12-01

    The seeds of winter wheat were pretreated with three different doses of low-energy N(+) beams, and its seedlings were subjected to UV-B irradiation (10.08 kJ m(-2) day(-1)) at three-leaves stage. The growth characteristic of seeds, the oxidative damage to membrane system induced by UV-B radiation, and the alleviating effects of N(+) beams pretreatment to radiation damage were investigated. The results showed that the germination rate and seedling rate, respectively, increased 14.09 ± 1.03 and 13.91 ± 1.21 % compared with control (CK) at the dose of 4.0 × 10(16) ions/cm(2). When seedlings were exposed to UV-B radiation, the pretreatment method under the dose of 4.0 × 10(16) ions/cm(2) made the activity of peroxidase and superoxide dismutase increasing, the content of chlorophyll enhancing, but the content of malondialdehyde reducing significantly compared with that of the single UV-B radiation. Whereas, the activity of catalase irradiated by UV-B improved notably under the pretreatment dose of 8.0 × 10(16) ions/cm(2). In addition, after being irradiated with UV-B, the content of soluble protein and glutathione whose seeds were pretreated by the dose of 6.0 × 10(16) ions/cm(2) were higher than that of the single UV-B radiation. It was suggested that the suitable dose of low-energy ion beams pretreatment to wheat seeds could change its physiological characteristics at seedlings stage to alleviate the damage effects from UV-B radiation. PMID:23054823

  19. 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.)

  20. 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)

  1. Gaseous mercury emissions from unsterilized and sterilized soils: The effect of temperature and UV radiation

    International Nuclear Information System (INIS)

    Mercury (Hg) emissions from the soils taken from two different sites (deciduous and coniferous forests) in the Adirondacks were measured in outdoor and laboratory experiments. Some of the soil samples were irradiated to eliminate biological activity. The result from the outdoor measurements with different soils suggests the Hg emission from the soils is partly limited by fallen leaves covering the soils which helps maintain relatively high soil moisture and limits the amount of heat and solar radiation reaching the soil surface. In laboratory experiments exposure to UV-A (365 nm) had no significant effect on the Hg emissions while the Hg emissions increased dramatically during exposure to UV-B (302 nm) light suggesting UV-B directly reduced soil-associated Hg. Overall these results indicate that for these soils biotic processes have a relatively constant and smaller influence on the Hg emission from the soil than the more variable abiotic processes. - Hg emission measurements from soils indicate that abiotic processes were more important than biotic processes in reducing Hg and controlling emissions.

  2. On the population of primordial star clusters in the presence of UV background radiation

    CERN Document Server

    MacIntyre, M A; Thomas, P A; Intyre, Michael A. Mac; Santoro, Fernando; Thomas, Peter A.

    2006-01-01

    We use the algorithm of Cole et al. (2000) to generate merger trees for the first star clusters in a Lambda CDM cosmology under an isotropic UV background radiation field, parametrized by J_21. We have investigated the problem in two ways: a global radiation background and local radiative feedback surrounding the first star clusters. Cooling in the first halos at high redshift is dominated by molecular hydrogen, H_2 - we call these Generation 1 objects. At lower redshift and higher virial temperature, T_vir > 10^4K, electron cooling dominates - we call these generation 2. Radiation fields act to photo-dissociate H_2, but also generate free electrons that can help to catalyse its production. At modest radiation levels, J_{21}/(1+z)^3 ~ 10^{-12}-10^{-7}, the nett effect is to enhance the formation of Generation 1 star-clusters. At higher fluxes the heating from photo-ionisation dominates and halts their production. With a realistic build-up of flux over time, the period of enhanced H_2 cooling is so fleeting as...

  3. Effect of ionizing (gamma and non-ionizing (UV radiation on the development of Trichogramma euproctidis (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    Tuncbilek Aydin S.

    2012-01-01

    Full Text Available The potential of using gamma and ultraviolet radiation as an alternative treatment to increase the efficiency of Trichogramma euproctidis (Girault 1911 (Hymenoptera: Trichogrammatidae was investigated in the laboratory. The developmental and adult stages of T. euproctidis were exposed to gamma radiation of different doses (0-30 Gy and ultraviolet radiation of 254 nm wavelengths (UV-C for different durations (0-10 min to assess their effect on each of the instars and their potential in breaking the developmental cycle of the egg parasitoid. The LD50 values for eggs, prepupae, pupae and adults were 8.1, 10.0, 22.7 and 9.5 Gy for gamma radiation and 9.5, 0.12, 2.0 and 11.9 min for UV radiation, respectively. The pupa and adult stages were more radioresistant to both gamma and UV radiation. The most interesting and unexpected result obtained for the prepupal stage was that UV radiation has a greater effect on prepupal stages than gamma radiation.

  4. Biochemical and ultrastructural changes in pollen of Zea mays L. grown under enhanced UV-B radiation

    International Nuclear Information System (INIS)

    The influence of ultraviolet-B (UV-B) radiation on the development of the male gametophyte was studied in Zea mays L. cv. LG12 grown in a growth chamber under PAR light supplemented with UV-B radiation and compared with a second set of plants grown under PAR light. Pollen samples collected from both groups of plants were cultured on germination medium and it was found that UV-B had no effect on pollen germination. Total pollen protein content was not affected but UV-B absorbing pigments increased. Some ultrastructural alterations were observed in pollen and pollen tubes, in particular large amounts of electron dense deposits were seen throughout the cytoplasm and in association with the pollen wall. In mature spikes of UV-B treated plants, anthers retained numerous pollen grains in their loculi while anthers of control plants were almost empty. UV-B treatment delayed flowering by 2±3 d. These results show that UV-B treatment of maize plants interferes with flowering, pollen ultrastructure and anther maturation even though pollen germination is unaffected. The significant increase of UV-B absorbing pigments in pollen grains could represent a defence mechanism that enables plants to complete their reproductive cycle. (author)

  5. Adaptive melanin response of the soil fungus Aspergillus niger to UV radiation stress at "Evolution Canyon", Mount Carmel, Israel.

    Directory of Open Access Journals (Sweden)

    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

  6. A flavonoid mutant of barley (Hordeum vulgare L.) exhibits increased sensitivity to UV-B radiation in the primary leaf

    International Nuclear Information System (INIS)

    The aim of the present investigation was to define the role of soluble flavonoids as UV-B protectants in the primary leaf of barley (Hordeum vulgare L.). For this purpose we used a mutant line (Ant 287) from the Carlsberg collection of proanthocyanidin-free barley containing only 7% of total extractable flavonoids in the primary leaf as compared to the mother variety (Hiege 550/75). Seven-day-old leaves from plants grown under high visible light with or without supplementary UV-B radiation were used for the determination of UV-B sensitivity. UV-B-induced changes were assessed from parameters of chlorophyll fluorescence of photosystem II, including initial and maximum fluorescence, apparent quantum yield, and photochemical and non-photochemical quenching. A quartz fibre-optic microprobe was used to evaluate the amount of potentially harmful UV-B (310 nm radiation) penetrating into the leaf as a direct consequence of flavonoid deficiency. Our data indicate an essential role of flavonoids in UV-B protection of barley primary leaves. In leaves of the mutant line grown under supplementary UV-B, an increase in 310nm radiation in the mesophyll and a strong decrease in the quantum yield of photosynthesis were observed as compared to the corresponding mother variety. Primary leaves of liege responded to supplementary UV-B radiation with a 30% increase in the major flavonoid saponarin and a 500% increase in the minor compound lutonarin. This is assumed to be an efficient protective response since no changes in variable chlorophyll fluorescence were apparent. In addition, a further reduction in UV-B penetration into the mesophyll was recorded in these leaves

  7. Low-temperature low-damage sterilization based on UV radiation through plasma immersion

    Science.gov (United States)

    Pollak, J.; Moisan, M.; Kéroack, D.; Boudam, M. K.

    2008-07-01

    This paper introduces a new type of high-frequency (HF) sustained discharge where the HF field applicator is a planar transmission line that allows us to fill with plasma a long chamber of rectangular cross-section (typically 1 m × 15 cm × 5 cm). Peculiar interesting features of this plasma source are a low gas temperature (typically below 40 °C in the 1 Torr range in argon), broadband impedance matching with no need for retuning, stability and reproducibility of the discharge (non-resonant behaviour). This type of plasma source could be useful for web processing; nonetheless, it is applied here to plasma sterilization, taking advantage of its low gas temperature to inactivate microorganisms on polymer-made medical devices to avoid damaging them. The predominant biocide species are the UV photons emitted by the discharge whereas most plasma sterilization techniques call for reactive species such as O atoms and OH molecules, which induce significant erosion damage on polymers. Polystyrene microspheres are actually observed to be erosion-free under the current plasma sterilization conditions (scanning electron micrographs have been examined). Moreover, inactivation is quite fast: 106 B. atrophaeus spores deposited on a Petri dish are inactivated in less than 1 min. Correlation of the UV radiation with the spore inactivation rate is examined by (i) considering the emitted light intensity integrated over the 112-180 nm vacuum UV (VUV) range with a photomultiplier; (ii) looking with an optical spectrometer at the emission spectrum over the 200-400 nm UV range; (iii) using absorption spectroscopy to determine the role of the VUV argon resonant lines (105 and 107 nm) on spore inactivation. It is found that the test-reference spores are mainly inactivated by VUV photons (112-180 nm) that are primarily emitted by impurities present in the argon plasma.

  8. Low-temperature low-damage sterilization based on UV radiation through plasma immersion

    International Nuclear Information System (INIS)

    This paper introduces a new type of high-frequency (HF) sustained discharge where the HF field applicator is a planar transmission line that allows us to fill with plasma a long chamber of rectangular cross-section (typically 1 m x 15 cm x 5 cm). Peculiar interesting features of this plasma source are a low gas temperature (typically below 40 deg. C in the 1 Torr range in argon), broadband impedance matching with no need for retuning, stability and reproducibility of the discharge (non-resonant behaviour). This type of plasma source could be useful for web processing; nonetheless, it is applied here to plasma sterilization, taking advantage of its low gas temperature to inactivate microorganisms on polymer-made medical devices to avoid damaging them. The predominant biocide species are the UV photons emitted by the discharge whereas most plasma sterilization techniques call for reactive species such as O atoms and OH molecules, which induce significant erosion damage on polymers. Polystyrene microspheres are actually observed to be erosion-free under the current plasma sterilization conditions (scanning electron micrographs have been examined). Moreover, inactivation is quite fast: 106 B. atrophaeus spores deposited on a Petri dish are inactivated in less than 1 min. Correlation of the UV radiation with the spore inactivation rate is examined by (i) considering the emitted light intensity integrated over the 112-180 nm vacuum UV (VUV) range with a photomultiplier; (ii) looking with an optical spectrometer at the emission spectrum over the 200-400 nm UV range; (iii) using absorption spectroscopy to determine the role of the VUV argon resonant lines (105 and 107 nm) on spore inactivation. It is found that the test-reference spores are mainly inactivated by VUV photons (112-180 nm) that are primarily emitted by impurities present in the argon plasma

  9. SYNTHESIS AND CHARACTERIZATION OF POLYURETHANE ACRYLATES FOR UV CURABLE COATING AGENTS

    OpenAIRE

    MI NA PARK; YOUNG SOO KANG; SUN WHA OH; BYUNG HYUN AHN; MYUNG JUN MOON

    2007-01-01

    The single hydroxyl-terminated urethane acrylate oligomers were synthesized from 2-mercaptoethanol (2-MEOH), alkyl (methyl, butyl, and 2-ethylhexyl) acrylate, and 2,2-azobisisobutyronitrile (AIBN, initiator), with dibutyltin dilaurate (DBTDL) as a catalyst. 2-MEOH was used as a functional chain transfer agent. Poly(alkyl urethane) acrylate oligomers were obtained by the reaction of single hydroxyl-terminated polyalkyl acrylates and 2-isocyanatoethyl acrylate. They were characterized by NMR, F...

  10. Response of bacteriophage T7 biological dosimeter to dehydration and extraterrestrial solar UV radiation

    Science.gov (United States)

    Hegedüs, M.; Fekete, A.; Módos, K.; Kovács, G.; Rontó, Gy.; Lammer, H.; Panitz, C.

    2007-02-01

    The experiment "Phage and uracil response" (PUR) will be accommodated in the EXPOSE facility of the ISS. Bacteriophage T7/isolated T7 DNA will be exposed to different subsets of extreme environmental parameters in space, in order to study the Responses of Organisms to the Space Environment (ROSE). Launch into orbit is preceded by EXPOSE Experiment Verification Tests (EVT) to optimize the methods and the evaluation. Bacteriophage T7/isolated T7 DNA thin layers were exposed to vacuum ( 10-6Pa), to monochromatic (254 nm) and polychromatic (200-400 nm) UV radiation in air as well as in simulated space vacuum. Using neutral density (ND) filters dose-effect curves were performed in order to define the maximum doses tolerated. The effect of temperature fluctuation in vacuum was also studied. The structural/chemical effects on bacteriophage T7/isolated T7 DNA were analyzed by spectroscopic and microscopical methods. Characteristic changes in the absorption spectrum and in the electrophoretic pattern of phage/DNA have been detected indicating the damage of isolated and intraphage DNA. DNA damage was also determined by quantitative PCR (QPCR) using 555 and 3826 bp fragments of T7 DNA. We obtained substantial evidence that DNA lesions (e.g. strand breaks, DNA-protein cross-links, cyclobutane pirimidine dimers (CPDs) etc.) accumulate throughout exposure. Preliminary results suggest a synergistic action of space vacuum and UV radiation with DNA being the critical target.

  11. Enhanced electrochemical oxidation of phenol by introducing ferric ions and UV radiation

    Institute of Scientific and Technical Information of China (English)

    MAO Xuhui; WEI Lin; HONG Song; ZHU Hua; LIN An; GAN Fuxing

    2008-01-01

    The mineralization of phenol in aerated electrochemical oxidation has been investigated. The results show that a cathodic Fenton process can occur when the Ti-0.3Mo-0.8Ni alloy material is used as cathode in solution containing ferric or ferrous ions; moreover,the reinforcement of cathodic Fenton process on the total organic carbon (TOC) removal rate of phenol is quite distinct. Among the metallic ions investigated, the ferric ion is the best catalyst for the electrochemical mineralization of phenol at initial pH 2.0, and the optimal concentration range is from 50 to 200 mg/L. The favorable pH range and supporting electrolyte (Na2SO4) concentration for mineralization of phenol in solution containing ferrous ions are 1.8-2.3 and below 0.10 mol/L, respectively. UV radiation can improve the TOC removal rate of phenol, but the enhanced effect varies in different solutions. In the solution containing ferric ions, an equal sum or synergetic effect can be observed. The optimal effect of electrolysis system under UV radiation is achieved in the solution containing 50 mg/L Fe3+ with a final removal percentage of 81.3%.

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

    Science.gov (United States)

    Goyal, Shruti; Amar, Saroj Kumar; Dubey, Divya; Pal, Manish Kumar; Singh, Jyoti; Verma, Ankit; Kushwaha, Hari Narayan; Ray, Ratan Singh

    2015-12-30

    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. PMID:26223015

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

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. Influence of UV and RTG radiation on levels of free amino acids in rat brain tissue

    International Nuclear Information System (INIS)

    Experiments were carried out with 204 Wistar rats divided into two experimental groups and control groups. Eighty-four rats of group 1 were UV-irradiated, and 90 rats of group 2 were irradiated with roentgen rays. Amino acids were separated by high-voltage electrophoresis and by paper chromatography. Changes in concentrations of amino acids in the brain tissue under the influence of UV radiation were analyzed after 24 hr in 5, 10, 20, 30, 50 and 90 day-old rats, and after 1, 2, 3 and in 8-day rats. The effect of irradiation with 1,200r of X rays was studied after 24 hr in rats in the same stages of development, and, in addition, the effect of 250r doses was observed in 3-day rats at 2, 7, 17, 27 and 47 days after roentgen irradiation. The following amino acids were assayed electrochromatographically: aspartic, glutamic and gamma-aminobutyric acids, alanine, glycine, serine, threonine, leucine and lysine. Brain levels of amino acids were raised under the influence of the factors applied, and ultraviolet and ionizing radiation had transient effect. (author)

  16. 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.

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

    Science.gov (United States)

    Kujanpää, J.; Kalakoski, N.

    2015-10-01

    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.

  18. Time sequence of the damage to the acceptor and donor sides of photosystem II by UV-B radiation as evaluated by chlorophyll a fluorescence

    OpenAIRE

    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 fluorometer revealed that the efficiency of photosystem II decreased both with increasing time of UV-B radiation and with increasing intensity of the UV-B. Fluorescence induction rise curves were analyzed us...

  19. On the interaction of UV-B radiation (280-315 mm) with water stress in crop plants

    International Nuclear Information System (INIS)

    Cowpea (Vigna unguiculata L. Walp.) seedlings (3-day-old) were subjected to 4 kinds of experimental treatments: (1) control without exposure to any stress (-D-UV), (2) moderate water stress with no UV-B irradiation (+D-UV), (3) no water stress but exposure to UV-B radiation (-D+UV), and (4) moderate water stress and exposure to UV-B (+D+UV). UV-B and drought stress in the combined form elicited beneficial effects on the morphological and growth characteristics, and a few additive inhibitory effects in some functional processes. An increase in the specific leaf weight (SLW) was observed in the combination of stresses, which could be a defence mechanism against UV-B. The combination of stresses promoted the synthesis of anthocyanins and phenolic compounds. The responses of plants to the combination of stresses indicate that during simultaneous exposure of plants to multiple stresses, one form of stress could minimize the damage by the other. The enhancement of superoxide dismutase (SOD) and catalase activities appear to serve as acclimation mechanisms to scavenge the toxic, free radicals of oxygen produced under stress conditions. However, the inhibition in nitrate metabolism was greater in the combined stresses than in either of the stresses imposed separately. The results of this study illustrate that the interaction of stresses during simultaneous multiple stress conditions brings out certain beneficial effects. (author)

  20. On the interaction of UV-B radiation (280-315 mm) with water stress in crop plants

    Energy Technology Data Exchange (ETDEWEB)

    Balakumar, T.; Vincent, V.H.B. (Univ of Stress Physiology and Plant Biochemistry, Dept. of Botany, The American College, Madurai (India)); Paliwal, K. (Dept. of Plant Sciences, Madurai Kamaraj Univ., Madurai (India))

    1993-01-01

    Cowpea (Vigna unguiculata L. Walp.) seedlings (3-day-old) were subjected to 4 kinds of experimental treatments: (1) control without exposure to any stress (-D-UV), (2) moderate water stress with no UV-B irradiation (+D-UV), (3) no water stress but exposure to UV-B radiation (-D+UV), and (4) moderate water stress and exposure to UV-B (+D+UV). UV-B and drought stress in the combined form elicited beneficial effects on the morphological and growth characteristics, and a few additive inhibitory effects in some functional processes. An increase in the specific leaf weight (SLW) was observed in the combination of stresses, which could be a defence mechanism against UV-B. The combination of stresses promoted the synthesis of anthocyanins and phenolic compounds. The responses of plants to the combination of stresses indicate that during simultaneous exposure of plants to multiple stresses, one form of stress could minimize the damage by the other. The enhancement of superoxide dismutase (SOD) and catalase activities appear to serve as acclimation mechanisms to scavenge the toxic, free radicals of oxygen produced under stress conditions. However, the inhibition in nitrate metabolism was greater in the combined stresses than in either of the stresses imposed separately. The results of this study illustrate that the interaction of stresses during simultaneous multiple stress conditions brings out certain beneficial effects. (au).

  1. Synthesis and evaluation of new protecting agents against ionizing radiations

    International Nuclear Information System (INIS)

    This thesis is devoted to the synthesis of new pulvinic acid derivatives and the evaluation of their antioxidant and radioprotective properties. This study has been conducted with the aim to develop new protecting agents against ionizing radiations. A new access to pulvinic acid derivatives was developed starting from L-dimethyl tartrate. It is based on a Dieckmann cyclization a dehydration and a Suzuki-Miyaura coupling. It allows a short effective preparation of various pulvinic acid derivatives: tetronic acid derivatives, mono-substituted pulvinic acid derivatives and methyl pulvinates. A modified method has been used to prepare pulvinones. This strategy gave access in four steps to the desired pulvinones. The rapidity of this method is provided by a tandem process, carried out in the final step, involving a Dieckmann cyclization and a β-elimination. A synthesis of 3-aryltetramic acids has also been developed in order to prepare nitrogen derivatives of pulvinic acid. The antioxidant activity of the prepared compounds was then evaluated using various tests: DPPH, ABTS, protection of thymidine and DNA study of lipid peroxidation. These evaluations allowed to define interesting structure-activity relationships of pulvinic derivatives. They have shown that several derivatives have very good antioxidant activities. Finally, radioprotective tests on TK6 cells and mice have have been performed on selected compounds. (author)

  2. Efficacy of agents counteracting hypoxia in fractionated radiation regimes

    International Nuclear Information System (INIS)

    Background and purpose: Solid tumours contain hypoxic cells which are resistant to radiotherapy. This study compares the efficacy of several strategies to counteract diffusion-limited hypoxia, or intermittent hypoxia in a fractionated regimen of 1 to 6 x 2 Gy. Materials and methods: Nicotinamide (250 mg/kg), perflubron emulsion (OxygentTM) (4 ml/kg), tirapazamine (SR4233) (0.10 mmol/kg) and carbogen breathing, administered alone or in combination, were investigated on two tumour cell lines: EMT6 (a rodent mammary carcinoma) and HRT18 (a human rectal adenocarcinoma) using a clonogenic assay. The radiosensitizing effect of the agents was assessed after 1 and 6 x 2 Gy for drugs used alone, and 1, 2, 4, 6 x 2 Gy for drugs used in combination. Results: At the end of the fractionated radiation regimen, the combination of nicotinamide + carbogen induced the greatest radiosensitization for EMT6 tumours, while greatest radiosensitization of HRT18 was obtained with nicotinamide + carbogen + tirapazamine. Conclusion: The efficacy of the strategies for overcoming hypoxia using a fractionated regimen depends on the tumour cell line. These differences could be linked to differences in the initial percentages of acute and chronic hypoxic cells, and to changes in the two types of hypoxia during treatment

  3. Ameliorating effect of UV-B radiation on the response of Norway spruce and Scots pine to ambient ozone concentrations

    International Nuclear Information System (INIS)

    Elevated levels of both ozone and UV-B radiation are typical for high-altitude sites. Few studies have investigated their possible interaction on plants. This study reports interactive effects of O3 and UV-B radiation in four-year-old Norway spruce and Scots pine trees. The trees were cultivated in controlled environmental facilities under simulated climatic conditions recorded on Mt Wank, an Alpine mountain in Bavaria, and were exposed for one growing season to simulated ambient or twice-ambient ozone regimes at either near ambient or near zero UV-B radiation levels. Chlorotic mottling and yellowing of current year needles became obvious under twice-ambient O3 in both species at the onset of a high ozone episode in July. Development of chlorotic mottling in relation to accumulated ozone concentrations over a threshold of 40 nL L–1 was more pronounced with near zero rather than ambient UV-B radiation levels. In Norway spruce, photosynthetic parameters at ambient CO2 concentration, measured at the end of the experiment, were reduced in trees cultivated under twice-ambient O3, irrespective of the UV-B treatment. Effects on photosynthetic capacity and carboxylation efficiency were restricted to trees exposed to near zero levels of UV-B radiation, and twice-ambient O3. The data indicate that UV-B radiation, applied together with O3, ameliorates the detrimental effects of O3. The data also demonstrate that foliar symptoms develop more rapidly in Scots pine than in Norway spruce at higher accumulated ozone concentrations. (author)

  4. Survival of thermophilic and hyper-thermophilic microorganisms after exposure to UV-C, ionizing radiation and desiccation

    International Nuclear Information System (INIS)

    In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylo-genetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyper-thermophilic microorganisms. (authors)

  5. Effects of UV-B radiation on soybean yield and seed quality: a 6-year field study

    International Nuclear Information System (INIS)

    Two soybean [Glycine max (L.) Merr.] cultivars, Essex and Williams, were grown in the field for 6 consecutive seasons under ambient and supplemental levels of ultravio-Set-B radiation to determine the potential for alterations in yield or seed quality with a reduction in the stratospheric ozone column. The supplemental UV-B fluences simulated a 16 or 25% ozone depletion. The data presented here represent the first field experiment conducted over multiple seasons which assesses the effects of increased UV-B radiation on seed yield. Overall, the cultivar Essex was found to be sensitive to UV-B radiation (yield reductions of 20%) while the cultivar Williams was tolerant. However, the effectiveness of UV-B radiation in altering yield was strongly influenced by the seasonal microclimate, and the 2 cultivars responded differently to these changing factors. Yield was reduced most in Essex during seasons in which water availability was high and was reduced in Williams only when water was severely limiting. The results of these experiments demonstrate the necessity for multiple-year experiments and the need to increase our understanding of the interaction between UV-B radiation and other environmental stresses in order to assess the potential consequences of stratospheric ozone depletion. (author)

  6. KCl:Eu2+ as a solar UV-C radiation dosimeter.Optically stimulated luminescence and thermoluminescence analyses

    Institute of Scientific and Technical Information of China (English)

    I.Aguirre de Cáarcer; H.L.D'Antoni; M.Barboza-Flores; V.Correcher; F.Jaque

    2009-01-01

    The KCl:Eu2+ system response to UV-C was investigated by analyzing the optically stimulated luminescence (OSL) and thertoo-luminescence (TL) signal produced by ultraviolet light exposure at room temperature.It was found that after UV-C irradiation,OSL was produced on a wide band of visible wavelengths with decay time that varied by several orders of magnitude depending on the Eu2+ aggregation state.In spite of the low intensity of solar UV-C reaching the Earth's surface in Madrid (40° N,700 m a.s.l.),it was possible to measure the UV-C radiation dose at 6:48 solar time by using the TL response of the KCl:Eu2+ system and differentiate it from the ambient beta radiation dose.

  7. Absorption of UV-B to blue light radiation by leaf cuticles of selected crop plants

    International Nuclear Information System (INIS)

    Plants have protective pigments absorbing destructive shortwave radiation. These pigments have been found in the epidermis and mesophyll of leaves. We studied the absorption characteristics of the leaf cuticle, the outermost part of the epidermis that is directly exposed to radiation. Adaxial leaf cuticles of apple, pear, sour cherry, strawberry, cauliflower, sugarbeet, and 13 other plant species were tested. The UV-B absorption was highest in Citrus aurantium and Citrus maxima (<3 % transmittance) and lowest in sugarbeet and peach (>64 % transmittance). The absorption maxima are at wavelenghts below 320 nm. Significant absorption was also determined at 500 nm, which correlated with cuticle thickness of the plant species (r(2)=0.72). The absorption in the range of 250 to 350 nm is caused by pigments with a high extinction coefficient. This absorption is species dependent and the patterns were designated to three different types. The highest absorption was found in evergreen species. The extraction of cuticular waxes had little effect on absorption. The specific absorption of shortwave radiation by plant cuticles is probably caused by pigments covalently bound to cut in. It is known for some plant species that cuticles can contain the phenolics p-coumaric acid, ferulic acid, and vanillic acid. Mixtures of these phenolics had spectra similar to cuticles. For most species absorption of shortwave radiation by the cuticle alone does not give complete protection

  8. 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. PMID:10343405

  9. In-situ monitoring of biologically active solar UV-B radiation: a new biosensor of vitamin D synthetic capacity

    Science.gov (United States)

    Terenetskaya, Irina P.; Gvozdovskyy, I. A.

    2001-06-01

    The new biosensor of vitamin D synthetic capacity of solar/artificial UV-B radiation is based on liquid crystal with provitamin D dopant. Nematic liquid crystals (LC-805, ZLI-1695) are converted into induced cholesteric phase using photosensitive steroid biomolecules of provitamin D3 (7- dehydrocholesterol). During UV exposure remarkable decrease in the number of the Cano-Grandjean stripes has been observed in the wedge-like cell as a result of UV initiated photoisomerization of provitamin D3 that changed helical twisting power of the dopant molecules.

  10. DNA repair pathways involved in determining the level of cytotoxicity of environmentally relevant UV radiation

    International Nuclear Information System (INIS)

    The sensitivity of cell lines with defects in various DNA repair processes to different wavelengths of UV has been assessed in order to determine the importance of these repair pathways to the cytotoxicity of UV light. The cell lines used in this work were xrs-6 (a Chinese Hamster Ovary (CHO) cell line) mutant for XRCC5/Ku80, EM9 a CHO cell line mutant for XRCC1, UV61 a CHO cell line mutant for ERCC6/CSB, and E3p53-/-, a mouse embryonic fibroblast cell line null for p53. Xrs-6 (defective in Non Homologous End-Joining) was found to be sensitive to the cytotoxic effects of broadband UVA, but not narrowband UVA or narrowband UVB. EM9 (defective in Base Excision Repair/Single-Strand Break Repair) was not sensitive to the cytotoxic effects of both broadband and narrowband UVA, narrowband UVB or narrowband UVC. UV61 (defective in the Transcription Coupled Repair branch of Nucleotide Excision Repair) was sensitive to the cytotoxic effects of narrowband UVA, UVB and UVC. E3p53-/- was sensitive to the cytotoxic effects of narrowband UVA and UVB. Broadband UVA was found to induce high levels of chromosomal damage in xrs-6, as quantified by the micronucleus assay, most likely as a result of this cell lines inability to repair DNA double strand breaks. EM9 was found to be defective in the repair of broadband UVA-induced single strand breaks, as measured by the alkaline gel electrophoresis ('comet') assay. UV61 was unable to repair broadband UVB-induced DNA damage as measured by the alkaline gel electrophoresis ('comet') assay. These results provide evidence that: 1. DNA double-strand breaks contribute to the cytotoxicity of UVA to a greater extent than single-strand breaks. 2. Repair mechanisms that operate in response to UVA may be coupled to transcription. 3. UVB may directly induce SSBs. 4. P53 is involved in the response of the cell to both UVA and UVB radiation. (author)

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

    International Nuclear Information System (INIS)

    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. (paper)

  12. Mouse Models for Efficacy Testing of Agents against Radiation Carcinogenesis—A Literature Review

    OpenAIRE

    Leena Rivina; Robert Schiestl

    2012-01-01

    As the number of cancer survivors treated with radiation as a part of their therapy regimen is constantly increasing, so is concern about radiation-induced cancers. This increases the need for therapeutic and mitigating agents against secondary neoplasias. Development and efficacy testing of these agents requires not only extensive in vitro assessment, but also a set of reliable animal models of radiation-induced carcinogenesis. The laboratory mouse (Mus musculus) remains one of the best anim...

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

    International Nuclear Information System (INIS)

    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 enhancedclose quotes), or 32% (open-quotes high enhancedclose quotes) ozone depletion levels at Morgantown, WV, USA in mid-March. In the first experiment,pollen production and viability per flower were reduced by ∼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 ∼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

  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. 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)

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

    International Nuclear Information System (INIS)

    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)

  17. Influence of UV-B radiation and Cd2+ on chlorophyll fluorescence, growth and nutrient content in Brassica napus

    International Nuclear Information System (INIS)

    The possible interaction of two stresses, UV-B radiation and cadmium, applied simultaneously, was investigated in Brassica napus L. cv. Paroll with respect to chlorophyll fluorescence, growth and uptake of selected elements. Plants were grown in nutrient solution containing CdCl2, (0, 0.5, 2 or 5 μM) and irradiated with photosynthetically active radiation (PAR, 400–700 nm, 800 μmol m−2 s−1) with or without supplemental ultraviolet-B radiation (UV-B, 280–320 nm, 15 kJ m−2 d−1, weighted irradiance). After 14 d of treatment, the most pronounced effects were found at 2 and 5 μM CdCl2 with and without supplemental UV-B radiation. Exposure to cadmium significantly increased the amount of Cd in both roots and shoots. In addition, increases occurred in the concentration of Fe, Zn, Cu, and P in roots, while K was reduced. In shoots the S content rose significantly both in the presence and absence of UV-B radiation, while significant increases in Mg, Ca, P, Cu, and K occurred only in plants exposed to Cd and UV-B radiation. Manganese decreased significantly under the combined exposure treatment. The rise in S content may have been due to stimulated glutathione and phytochelatin synthesis. Cadmium exposure significantly decreased root dry weight, leaf area, total chlorophyll content, carotenoid content, and the photochemical quantum yield of photosynthesis. As an estimation of energy dissipation processes in photosynthesis, non photochemical quenching (qNPQ) was measured using a pulse amplitude modulated fluorometer. The qNPQ increased with increasing Cd, while the combination of cadmium and UV-B reduced the qNPQ compared to that in plants exposed only to cadmium or UV-B radiation. The chlorophyll a : b ratio showed a reduction with UV-B at no or low Cd concentrations (0 μM, 0.5 μM CdCl2), but not at the higher Cd concentrations used (2 μM, 5 μM CdCl2). Thus in some instances there appeared to be a UV-B and Cd interaction, while in others plant response

  18. Protein kinases and transcription factors activation in response to UV-radiation of skin: implications for carcinogenesis.

    Science.gov (United States)

    López-Camarillo, César; Ocampo, Elena Aréchaga; Casamichana, Mavil López; Pérez-Plasencia, Carlos; Alvarez-Sánchez, Elizbeth; Marchat, Laurence A

    2012-01-01

    Solar ultraviolet (UV) radiation is an important environmental factor that leads to immune suppression, inflammation, photoaging, and skin carcinogenesis. Here, we reviewed the specific signal transduction pathways and transcription factors involved in the cellular response to UV-irradiation. Increasing experimental data supporting a role for p38, MAPK, JNK, ERK1/2, and ATM kinases in the response network to UV exposure is discussed. We also reviewed the participation of NF-κB, AP-1, and NRF2 transcription factors in the control of gene expression after UV-irradiation. In addition, we discussed the promising chemotherapeutic intervention of transcription factors signaling by natural compounds. Finally, we focused on the review of data emerging from the use of DNA microarray technology to determine changes in global gene expression in keratinocytes and melanocytes in response to UV treatment. Efforts to obtain a comprehensive portrait of the transcriptional events regulating photodamage of intact human epidermis after UV exposure reveals the existence of novel factors participating in UV-induced cell death. Progress in understanding the multitude of mechanisms induced by UV-irradiation could lead to the potential use of protein kinases and novel proteins as specific targets for the prevention and control of skin cancer. PMID:22312244

  19. Protein Kinases and Transcription Factors Activation in Response to UV-Radiation of Skin: Implications for Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Laurence A. Marchat

    2011-12-01

    Full Text Available Solar ultraviolet (UV radiation is an important environmental factor that leads to immune suppression, inflammation, photoaging, and skin carcinogenesis. Here, we reviewed the specific signal transduction pathways and transcription factors involved in the cellular response to UV-irradiation. Increasing experimental data supporting a role for p38, MAPK, JNK, ERK1/2, and ATM kinases in the response network to UV exposure is discussed. We also reviewed the participation of NF-κB, AP-1, and NRF2 transcription factors in the control of gene expression after UV-irradiation. In addition, we discussed the promising chemotherapeutic intervention of transcription factors signaling by natural compounds. Finally, we focused on the review of data emerging from the use of DNA microarray technology to determine changes in global gene expression in keratinocytes and melanocytes in response to UV treatment. Efforts to obtain a comprehensive portrait of the transcriptional events regulating photodamage of intact human epidermis after UV exposure reveals the existence of novel factors participating in UV-induced cell death. Progress in understanding the multitude of mechanisms induced by UV-irradiation could lead to the potential use of protein kinases and novel proteins as specific targets for the prevention and control of skin cancer.

  20. Extreme UV harmonic production by free-electron generators of coherent radiation

    International Nuclear Information System (INIS)

    The bunching phenomenon is the basic process occurring in a free-electron generator of coherent generation such as the Klystron in the mm-wave-length range or the free-electron laser (FEL) in the optical region. During interaction with the incident electromagnetic wave the electrons are progressively gathered into small packets separated by a length equal to its wavelength λ/sub L/. Once the electrons are bunched there is a given phase relationship between them and the field of any wave which wavelength is an harmonic of λ/sub L/. This is the source of the gain (electrons decelerated by the field) or of the absorption (electrons accelerated by the laser) mechanisms. In the FEL case the electrons are passing through an undulator (spatially varying periodic magnetic field). Since one uses high-energy electrons (E≅100-1000 MeV) they emit synchrotron radiation called in this case undulator radiation or spontaneous emission. This radiation coexists with the stimulated emission giving rise to the gain mechanism and to the FEL oscillation. When the electrons are bunched the spontaneous emission becomes coherent at the wavelength harmonic of λ/sub L/, and there is an increase in the emission intensity which ideally would be N/sub e/. (Number of electrons is typically ≅10/sup 10/.) Thus bursts of photons are emitted at frequencies harmonic of an incident wave which may be an external laser or the FEL itself. This is likely to extend the spectral range of the free-electron generation of coherent radiation toward the extreme UV λ<1000A). The advantages and limitations of the various solutions (linear or circular accelerator, FEL, or external laser) are discussed. The authors summarize the various experimental results obtained to date and the prospects for the synchrotron radiation dedicated ring super-ACO presently under construction at LURE at Orsay

  1. Nanoparticle effects on the thermoluminescent properties of monoclinic ZrO2 exposed to UV radiation

    International Nuclear Information System (INIS)

    In this work, an analysis of the thermoluminescent (TL) signal induced by ultraviolet radiation in monoclinic zirconium oxide (ZrO2) doped with metallic nanoparticles is presented. Thermoluminescent response of pure ZrO2 shows two peaks, the first one at 61 C and the second one at 144 C when it was exposed to UV radiation; being the first peak more intense than the second. When nanoparticles are added, the glow curve also shows two peaks, however, the intensity and the glow curve shape was lightly different depending of the kind of the nanoparticles added. For example, ZrO2 with Au nanoparticles or Au-Pd nanoparticles produced a glow curve with two peaks almost with same intensity. These results indicate that there is an influence of the-metallic nanoparticles on the TL response. This study was complemented with an analysis of the fading behavior to evaluate the possibility to use this kind of material as dosimeter of ultraviolet radiation. (Author)

  2. Formation of DNA lesions in cucumber cotyledons exposed to solar UV radiation

    International Nuclear Information System (INIS)

    Photoinduced lesions in DNA, namely, cyclobutane pyrimidine dimers (CPDs) and pyrimidine- (6-4) -pyrimidone photoproducts [(6-4) photoproducts], in cucumbercotyledons exposed to solar radiation in Sapporo (N 43°) Okinawa (Iriomotejima is., N 24°) quantified by enzyme-linked immunosorbent assays (ELISAs) with monoclonal antibodies specific to each type of photolesion. The amount of (6-4) photoproducts increased with increasing dosage of solar radiation (photosyntheticphoton flux, PPF). In contrast, the relationship between the amount of CPDs and PPF was not clear, probably due to the higher activity of light-dependent repair of CPDs as compared with that of (6-4) photoproducts. The amount of photolesions in Okinawa tended to be greater than in Sapporo at the same PPF dose probably due to the difference of ozone layer thickness, suggesting the likely future effects on plants of the increased UV-B radiation that will be a consequence of depletion of the ozone layer. Changes in the amounts of DNA lesions were different between CPDs and (6-4) photoproducts. CPDs decreased in the evening, but any noticeable decrease in the amount of (6-4) photoproducts was not observed, probably resulting from the differences in light-dependent repair activities of these lesions in cucumber cotyledons. (author)

  3. UV radiation in the water treatment. Application for the drinking industry; Radiacion ultravioleta en el tratamiento de aguas

    Energy Technology Data Exchange (ETDEWEB)

    Natta March, J. M.; Frontera Frau, F.

    2000-07-01

    The disinfection is one of the basic matters in the treatment of drinking water. The systematic use of chemical substances (chlorine and its by-products) and the recent use of UV radiation have both reduced, in an spectacular way, the existence of microorganisms in bottled waters and in waters for industrial use. The aim of this article is to show, in a general way, the mechanism of behaviour of the UV radiation and, at the same time, to point out the advantages and disadvantages of this technique for the drinking industry. (Author) 8 refs.

  4. Changes in leaf mineral composition and chloroplast proteins induced by K-deficiency and increased UV-B radiation

    International Nuclear Information System (INIS)

    Solar UV-B radiation increased to 20 % over ambient level at Madurai was given to cowpea (Vigna unguiculata cv. Pusa-152) seedlings sufficiently supplied by potassium (0.88 mM K2SO4) and K-deficient (0.05 mM K2SO4). Leaf mineral composition was significantly changed due to both increased UV-B radiation and K-deficiency imposed independently or jointly for 12 d. A severe reduction in 23 kDa chloroplast protein was seen only in seedlings encountered combined stress

  5. Role of Dipicolinic Acid in Survival of Bacillus subtilis Spores Exposed to Artificial and Solar UV Radiation

    OpenAIRE

    Slieman, Tony A.; Nicholson, Wayne L.

    2001-01-01

    Pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) constitutes approximately 10% of Bacillus subtilis spore dry weight and has been shown to play a significant role in the survival of B. subtilis spores exposed to wet heat and to 254-nm UV radiation in the laboratory. However, to date, no work has addressed the importance of DPA in the survival of spores exposed to environmentally relevant solar UV radiation. Air-dried films of spores containing DPA or lacking DPA due to a null mutation ...

  6. Effect of UV Radiation on the Spectral Fingerprints of Earth-like Planets Orbiting M dwarfs

    CERN Document Server

    Rugheimer, S; Segura, A; Linsky, J; Mohanty, S

    2015-01-01

    We model the atmospheres and spectra of Earth-like planets orbiting the entire grid of M dwarfs for active and inactive stellar models with $T_{eff}$ = 2300K to $T_{eff}$ = 3800K and for six observed MUSCLES M dwarfs with UV radiation data. We set the Earth-like planets at the 1AU equivalent distance and show spectra from the VIS to IR (0.4$\\mu$m - 20$\\mu$m) to compare detectability of features in different wavelength ranges with JWST and other future ground- and spaced-based missions to characterize exo-Earths. We focus on the effect of UV activity levels on detectable atmospheric features that indicate habitability on Earth, namely: H$_2$O, O$_3$, CH$_4$, N$_2$O and CH$_3$Cl. To observe signatures of life - O$_2$/O$_3$ in combination with reducing species like CH$_4$, we find that early and active M dwarfs are the best targets of the M star grid for future telescopes. The O$_2$ spectral feature at 0.76$\\mu$m is increasingly difficult to detect in reflected light of later M dwarfs due to low stellar flux in ...

  7. Studies on the kinetics of gel formation in polyurethane acrylate cured by UV-radiation

    International Nuclear Information System (INIS)

    In this paper, the kinetics of gel formation in polyurethane acrylate initiated by UV-radiation was investigated with the help of IR spectra, in which benzophenone/benzoic ethyl ether was a mixed photo sensitizer. The reaction degrees of double-bonds changing at 1408 cm-1 of acrylates in IR were detected in the different UV exposure time. The relationship between reaction degree Pc-c = 0.325 t0.135. After a critical geloint, the reaction degrees of double-bonds existed: Pc=c (gel) > Pc=c > Pc=c(sol) and besides there was a distributional relation between gel and sol fractions in the whole processing. The critical gel point was obtained with the extrapolation method, and its experimental gel point and the theoretical modeling one were quite close to each other. The experimental curves of Pc=c, Pc=c(gel) and Pc=c(sol) functions related to gel fractions were in fairly good agreement with their theoretical modeling ones in both shape and tendency

  8. Combined Treatment of UV and Gamma Radiation of Papaya for Decay Control

    International Nuclear Information System (INIS)

    An exploratory study was made to determine if combining u.v. and gamma radiation treatment at selective doses would decrease the fungal decay incidence in papaya (Carica papaya L. var. Solo), and thereby increase the marketable life of the fruit. Also studied was the effect of the combined treatment on the spores of Aschochyta spp., Colletotrichium spp. and Phytophthora spp., which are commonly found on papaya grown in Hawaii. This was to test the postulate that the combined treatment would prevent photoreactivation of the disrupted nuclei in microorganisms and lead to eventual death. Experimental results did not indicate a conclusive trend to effectiveness but suggested a number of problems to be resolved before the treatment can become useful in fungal decay control of fruits. (author)

  9. 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.

  10. Long-wave UV radiation-induced activation of enzymic conversion of 5-hydroxytriptophan to serotonin

    International Nuclear Information System (INIS)

    In experiments using yeast extracts longwave UV radiation (337 nm) was found to activate enzymic decarboxylation producing serotonin. The activation effect was investigated as a function of irradiation intensity and fluence, and pH. Decarboxylase was seen to be photoactivated at pH close to neutral values (low activity of enzyme in the dark); no photoactivation was observed at acidic pH (high enzymic activity). The data show that the effect of light is similar to a pH shift towards the acidic region, leading to a transition of the inactive enzyme to its active form. It is suggested that the role of photoactive chromophore of active decarboxylase is played by its cofactor, pyridoxal phosphate adduct, that absorbs at 330-340 nm

  11. 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.

  12. Combined treatment of UV and gamma radiation of papaya for decay control

    International Nuclear Information System (INIS)

    An exploratory study was made to determine if combining u.v. and gamma radiation treatment at selective doses would decrease the fungal decay incidence in papaya (Carica papaya L. var. Solo), and thereby increase the marketable life of the fruit. Also studied was the effect of the combined treatment on the spores of Aschochyta spp., Colletotrichium spp. and Phytophthora spp., which are commonly found on papaya grown in Hawaii. This was to test the postulate that the combined treatment would prevent photoreactivation of the disrupted nuclei in microorganisms and lead to eventual death. Experimental results did not indicate a conclusive trend to effectiveness but suggested a number of problems to be resolved before the treatment can become useful in fungal decay control of fruits. (author)

  13. Radiation and a dynamical UV/IR connection in AdS/CFT

    CERN Document Server

    Agon, Cesar A; Pedraza, Juan F

    2014-01-01

    We compute holographically the expectation value of the energy density sourced, in a strongly-coupled CFT, by a quark with large but finite mass (or equivalently, small but finite Compton radius) undergoing arbitrary motion. The resulting gluonic profile has two surprising features in the far region. First, besides the expected radiation, it contains a component that is attributable to the `intrinsic' or `near' field of the quark, and nevertheless falls off as the square of the distance. Second, even at distances much larger than the size of the quark, it differs from the profile set up by a pointlike quark. We explain how this second feature provides a useful case study for the UV/IR connection in a dynamical setting. We also examine some specific sample trajectories, including uniform circular motion and harmonic oscillation, where features such as the extent of the region with negative energy are found to vary with the quark mass.

  14. 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.

  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

    International Nuclear Information System (INIS)

    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/m2) 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/m2 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. Aerosol radiative forcing efficiency in the UV-B region over central Argentina

    Science.gov (United States)

    Palancar, Gustavo G.; Olcese, Luis E.; Lanzaco, Bethania L.; Achad, Mariana; López, María Laura; Toselli, Beatriz M.

    2016-07-01

    AEROSOL Robotic Network (AERONET), Moderate Resolution Imaging Spectroradiometer (MODIS) and global UV-B (280-315 nm) irradiance measurements and calculations were combined to investigate the effects of aerosol loading on the ultraviolet B radiation (UV-B) reaching the surface under cloudless conditions in Córdoba, Argentina. The aerosol radiative forcing (ARF) and the aerosol forcing efficiency (ARFE) were calculated for an extended period of time (2000-2013) at a ground-based monitoring site affected by different types and loading of aerosols. The ARFE was evaluated by using the aerosol optical depth (AOD) at 340 nm retrieved by AERONET at the Cordoba CETT site. The individual and combined effects of the single scattering albedo (SSA) and the solar zenith angle (SZA) on the ARFE were also analyzed. In addition, and for comparison purposes, the MODIS AOD at 550 nm was used as input in a machine learning method to better characterize the aerosol load at 340 nm and evaluate the ARFE retrieved from AOD satellite measurements. The ARFE at the surface calculated using AOD data from AERONET ranged from (-0.11 ± 0.01) to (-1.76 ± 0.20) Wm-2 with an average of -0.61 Wm-2; however, when using AOD data from MODIS (TERRA/AQUA satellites), it ranged from (-0.22 ± 0.03) to (-0.65 ± 0.07) Wm-2 with an average value of -0.43 Wm-2. At the same SZA and SSA, the maximum difference between ground and satellite-based was 0.22 Wm-2.

  17. Effects of UV radiation and drouhgt on the accumulation of UV-screening compounds and photosynthetic parameters in selected herbs and grasses of the mountain grassland ecosystem

    Czech Academy of Sciences Publication Activity Database

    Klem, Karel; Holub, Petr; Urban, Otmar; Rajsnerová, Petra; Kubásek, Jiří

    Brno : Global change research centre, Academy of Sciences of the Czech Republic, v. v. i, 2013 - (Stojanov, R.; Žalud, Z.; Cudlín, P.; Farda, A.; Urban, O.; Trnka, M.), s. 237-241 ISBN 978-80-904351-8-6. [Global Change and Resilience. Brno (CZ), 22.05.2013-24.05.2013] R&D Projects: GA ČR GA522/09/0468; GA MŠk LD12030; GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : uv radiation * uv-screening * photosynthetic parametrs * grassland ecosystem Subject RIV: EH - Ecology, Behaviour

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

    Institute of Scientific and Technical Information of China (English)

    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 0.15 W/m2 and 0.45 W/m2 significantly affected the whole nitrogen metabolism in soybean seedlings (p < 0.05). It restricted uptake and transport of NO3-, inhibited activity of some key nitrogen-metabolism-related enzymes such as nitrate reductase (NR) related to the nitrate reduction, as well as glutamine systhetase (GS) and glutamine synthase (GOGAT) related 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 one. 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.

  19. Status of miniature integrated UV resonance fluorescence and Raman sensors for detection and identification of biochemical warfare agents

    Science.gov (United States)

    Hug, William F.; Bhartia, Rohit; Taspin, Alexandre; Lane, Arthur; Conrad, Pamela; Sijapati, Kripa; Reid, Ray D.

    2005-11-01

    Laser induced native fluorescence (LINF) is the most sensitive method of detection of biological material including microorganisms, virus', and cellular residues. LINF is also a sensitive method of detection for many non-biological materials as well. The specificity with which these materials can be classified depends on the excitation wavelength and the number and location of observation wavelengths. Higher levels of specificity can be obtained using Raman spectroscopy but a much lower levels of sensitivity. Raman spectroscopy has traditionally been employed in the IR to avoid fluorescence. Fluorescence rarely occurs at wavelength below about 270nm. Therefore, when excitation occurs at a wavelength below 250nm, no fluorescence background occurs within the Raman fingerprint region for biological materials. When excitation occurs within electronic resonance bands of the biological target materials, Raman signal enhancement over one million typically occurs. Raman sensitivity within several hundred times fluorescence are possible in the deep UV where most biological materials have strong absorption. Since the Raman and fluorescence emissions occur at different wavelength, both spectra can be observed simultaneously, thereby providing a sensor with unique sensitivity and specificity capability. We will present data on our integrated, deep ultraviolet, LINF/Raman instruments that are being developed for several applications including life detection on Mars as well as biochemical warfare agents on Earth. We will demonstrate the ability to discriminate organic materials based on LINF alone. Together with UV resonance Raman, higher levels of specificity will be demonstrated. In addition, these instruments are being developed as on-line chemical sensors for industrial and municipal waste streams and product quality applications.

  20. P1 Epigenetic Regulation in Leaves of High Altitude Maize Landraces: Effect of UV-B Radiation

    Science.gov (United States)

    Rius, Sebastián P.; Emiliani, Julia; Casati, Paula

    2016-01-01

    P1 is a R2R3-MYB transcription factor that regulates the accumulation of a specific group of flavonoids in maize floral tissues, such as flavones and phlobaphenes. P1 is also highly expressed in leaves of maize landraces adapted to high altitudes and higher levels of UV-B radiation. In this work, we analyzed the epigenetic regulation of the P1 gene by UV-B in leaves of different maize landraces. Our results demonstrate that DNA methylation in the P1 proximal promoter, intron1 and intron2 is decreased by UV-B in all lines analyzed; however, the basal DNA methylation levels are lower in the landraces than in B73, a low altitude inbred line. DNA demethylation by UV-B is accompanied by a decrease in H3 methylation at Lys 9 and 27, and by an increase in H3 acetylation. smRNAs complementary to specific regions of the proximal promoter and of intron 2 3′ end are also decreased by UV-B; interestingly, P1 smRNA levels are lower in the landraces than in B73 both under control conditions and after UV-B exposure, suggesting that smRNAs regulate P1 expression by UV-B in maize leaves. Finally, we investigated if different P1 targets in flower tissues are also regulated by this transcription factor in response to UV-B. Some targets analyzed show an induction in maize landraces in response to UV-B, with higher basal expression levels in the landraces than in B73; however, not all the transcripts analyzed were found to be regulated by UV-B in leaves. PMID:27148340

  1. Short-term UV-B radiation affects photosynthetic performance and antioxidant gene expression in highbush blueberry leaves.

    Science.gov (United States)

    Inostroza-Blancheteau, Claudio; Acevedo, Patricio; Loyola, Rodrigo; Arce-Johnson, Patricio; Alberdi, Miren; Reyes-Díaz, Marjorie

    2016-10-01

    The impact of increased artificial UV-B radiation on photosynthetic performance, antioxidant and SOD activities and molecular antioxidant metabolism responses in leaves of two highbush blueberry (Vaccinium corymbosum L. cv. Brigitta and Bluegold) genotypes was studied. Plants were grown in a solid substrate and exposed to 0, 0.07, 0.12 and 0.19 W m(-2) of biologically-effective UV-B irradiance for 0-72 h. Our findings show that net photosynthesis (Pn) decreased significantly in Bluegold, accompanied by a reduction in the effective quantum yield (ФPSII) and electron transport rate (ETR), especially at the highest UV-B irradiation. On the other hand, Brigitta showed a better photosynthetic performance, as well as a clear increment in the antioxidant activity response that could be associated with increased superoxide dismutase activity (SOD) in the early hours of induced UV-B stress in all treatments. At the molecular level, the expression of the three antioxidant genes evaluated in both genotypes had a similar tendency. However, ascorbate peroxidase (APX) expression was significantly increased (6-fold) in Bluegold compared to Brigitta. Thus, the reduction of Pn concomitant with a lower photochemical performance and a reduced response of antioxidant metabolism suggest that the Bluegold genotype is more sensitive to UV-B radiation, while Brigitta appears to tolerate better moderate UV-B irradiance in a short-term experiment. PMID:27343876

  2. TiO2 nanoparticles as an effective UV-B radiation skin-protective compound in sunscreens

    International Nuclear Information System (INIS)

    Protecting human skin against harmful UV-B radiation coming from the sun is currently a problem. Due to the decreased thickness of the ozone layer, a more dangerous amount of UV-B light reaches the surface of our planet. This causes increased frequency of skin diseases. Titanium dioxide (TiO2) fine particles are embedded with sunscreens into the skin to effectively attenuate UV-B radiation. This study evaluates the most appropriate size of such particles assuming they are spheres. The distribution of TiO2 particles within the skin, achieved with topically applied sunscreens, is determined experimentally by the tape-stripping technique. Computer code implementing the Monte Carlo method is used to simulate photon migration within the plain 20 μm thick horny layer matrix partially filled with nano-sized TiO2 particles. Dependences of harmful UV-B radiation of 307-311 nm absorbed by, backscattered from and transmitted through the horny layer on the concentration of TiO2 particles are obtained and analysed. As a result, particles of 62 nm are found to be the most effective in protecting skin against UV-B light

  3. Additive effects in UV and radiation grafting and curing processes of value in immobilization of bioactive materials

    International Nuclear Information System (INIS)

    The scope of UV and ionizing radiation grafting techniques for the immobilization of bioactive materials is discussed. The principle of the method is outlined. This involves copolymerization of a monomer containing an appropriate functional group to a backbone polymer, then attachment of the reagent by subsequent chemical reactions. Novel additives which lower the total radiation dose in grafting have been discovered and their value in immobilization processes assessed. A theory for this additive effect in grafting is proposed. Methods for speeding up these radiation processes for immobilization involving sensitized UV and electron beam (EB) curing reactions are considered. The advantages of the curing technique for immobilization are summarized. Examples of typical enzymes immobilized by the above radiation processes are given. (author). 23 refs, 11 tabs

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

    Science.gov (United States)

    Rupiasih, N. Nyoman; Vidyasagar, Pandit B.

    2016-03-01

    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.

  5. The nopaline synthase (nos) promoter is inducible by UV-B radiation through a pathway dependent on reactive oxygen species

    International Nuclear Information System (INIS)

    The molecular mechanism of plant response to UV-B radiation was studied using the nopaline synthase (nos) promoter, which has been shown to be inducible by methyl jasmonate (MJ) and reactive oxygen species (ROS). In the leaves of transgenic tobacco (Nicotiana tabacum L.) plants that carried a fusion between the nos promoter and the chloramphenicol acetyltransferase (cat) gene, 2 h of UV-B treatment resulted in a transient increase in the level of cat mRNA, a maximum being reached at 6 h after the UV-B treatment. It was also found that MJ and UV-B enhance nos promoter expression via separate pathways. Diethyldithiocarbamic acid, a potent inhibitor of jasmonate production, had little effect on UV-B stimulation of the nos promoter. In contrast, antioxidants, such as dimethylthiourea, reduced glutathione, cysteine, N-acetylcysteine and DTT, blocked UV-B induction of the nos promoter, but did not affect MJ induction of the nos promoter. These results suggest that UV-B induction of the nos promoter is mediated via a pathway that requires reactive oxygen species and is distinct from the jasmonate or MJ mediating pathway. (author)

  6. 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.

    Science.gov (United States)

    Won, Eun-Ji; Han, Jeonghoon; Lee, Yeonjung; Kumar, K Suresh; Shin, Kyung-Hoon; Lee, Su-Jae; Park, Heum Gi; Lee, Jae-Seong

    2015-08-01

    To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0-3kJ/m(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 (Pphysiological balance and inhibits the ability to cope with UV-induced damage in P. nana. PMID:26001085

  7. UV-B辐射对马尾松凋落叶分解和养分释放的影响%Effect of UV-B radiation on the leaf litter decomposition and nutrient release of Pinus massoniana

    Institute of Scientific and Technical Information of China (English)

    宋新章; 张慧玲; 江洪; 余树全; 张智婷

    2011-01-01

    Ultraviolet-B radiation (UV-B, 280- 315 nm) reaching the earth's surface has been increasing due to stratospheric ozone depletion during the last several decades.Elevated UV-B radiation influenced ecosystem properties and functional processes such as plant litter decomposition and the subsequent nutrient release.As a key process in nutrient and carbon cycling of terrestrial ecosystems, plant litter decomposition converts the products of photosynthesis to inorganic compounds, representing one of the primary sources of nutrients for plants, and both nutrients and energy for microbes.At the same time, stable soil organic matter is formed as part of the litter decomposition processes.Therefore, UV-B induced changes in litter decomposition could profoundly influence primary production, carbon storage, and carbon and nutrient fluxes between the soil and atmosphere.UV-B radiation has direct and indirect effects on plant litter decomposition.Direct effects of UV-B radiation result from UV-B exposure during litter decomposition while indirect effects are caused by UV-B exposure during plant growth that changes the litter quality and the subsequent decomposition of the litter.Elevated UV-B radiation may directly increase litter decomposition via enhanced lignin photodegradation or decrease litter decomposition through reducing the abundance and altering the community composition of decomposers, as well as indirectly accelerate or slow the rate of decomposition through changing the litter chemistry during plant growth, even though some studies have found no pronounced indirect effects.Currently, the majority of decomposition studies on the effect of elevated UV-B radiation focused on the indirect effects on the chemical composition and decomposition of herbaceous plant leaf litter.In contrast, the direct effect of UV-B radiation on the decomposition of and nutrient release from leaf litter of woody plants has been less studied.Providing supplemental UV-B radiation with UV

  8. The combined effects of CO2 concentration and enhanced UV-B radiation on faba bean. 3. Leaf optical properties, pigments, stomatal index and epidermal cell density

    International Nuclear Information System (INIS)

    Seedlings of Vicia faba L. (cv. Minica) were grown in a factorial experiment in a greenhouse. The purpose of the study was to determine whether CO2 enrichment and supplemental UV-B radiation affect leaf optical properties and whether the combined effects differ from single factor effects. Seedlings were grown at either 380 μmol mol-1 or 750 μmol mol-1 CO2 and at four levels of UV-B radiation. After 20 and 40 days of treatment, absorptance, transmittance and reflectance of photosynthetically active radiation (PAR) were measured on the youngest fully developed leaf. On the same leaf, the specific leaf area on a fresh weight basis (SLAfw), chlorophyll content, UV-B absorbance, transmittance of UV light and stomatal index were measured. UV-B radiation significantly increased PAR absorptance and decreased PAR transmittance. The increased PAR absorptance can be explained by an increased chlorophyll content in response to UV-B radiation. Leaf transmittance of UV radiation decreased with increasing UV-B levels mainly caused by increased absorbance of UV absorbing compounds. UV-B radiation decreased both the stomatal density and epidermal cell density of the abaxial leaf surface, leaving the stomatal index unchanged. Effects of CO2 enrichment were less pronounced than those of UV-B radiation. The most important CO2 effect was an increase in stomatal density and epidermal cell density of the adaxial leaf surface. The stomatal index was not affected. No interaction between CO2 and UV-B radiation was found. The results are discussed in relation to the internal light environment of the leaf. (author)

  9. Potential of Ozone Formation by the Smog Mechanism to shield the surface of the Early Earth from UV radiation?

    CERN Document Server

    Grenfell, J L; Patzer, B; Titz, R; Rauer, H; Grenfell, John Lee; Stracke, Barbara; Patzer, Beate; Titz, Ruth; Rauer, Heike

    2006-01-01

    We propose that the photochemical smog mechanism produced substantial ozone (O3) in the troposphere during the Proterozoic, which contributed to ultraviolet (UV) radiation shielding hence favoured the establishment of life. The smog mechanism is well-established and is associated with pollution hazes which sometimes cover modern cities. The mechanism proceeds via the oxidation of volatile organic compounds (VOCs) such as methane (CH4) in the presence of UV radiation and nitrogen oxides (NOx). It would have been particularly favoured during the Proterozoic given the high levels of CH4 (up to 1000 ppm) recently suggested. Proterozoic UV levels on the surface of the Earth were generally higher compared with today, which would also have favoured the mechanism. On the other hand, Proterozoic O2 required in the final step of the smog mechanism to form O3 was less abundant compared with present times. Further, results are sensitive to Proterozoic NOx concentrations, which are challenging to predict, since they depen...

  10. PTTL method applied to UV radiation detection during refractive surgery using excimer laser

    International Nuclear Information System (INIS)

    The method of photo-transferred thermoluminescence (PTTL), using CaSO4:Dy pellets produced at IPEN as sensitive material, was used to detect the spread laser radiation inside the surgery room during refractive surgical procedures using ArF excimer lasers. The purpose of this work was to study the viability of performing the ultraviolet radiation (UVR) exposure detection of patients and the hospital's surgical staff during a refractive surgery. The CaSO4:Dy pellets were positioned at different distances from the laser source inside the surgery room: patient's (≅0.15 m), surgeon's (≅0.5 m) and nurse's (≅1.0 m) foreheads, lateral (≅1.5 m) and back (≅4.0 m) walls. The measurements of PTTL were carried out at two different conditions: five surgeries, each one taking ∼10 min, and during a period of 4 h (cumulative), when several operations were performed. The detectors positioned as far as 4.0 m from the UV laser source were sensitised, making the UVR detection feasible at large source-detector distances. The absorbed energy was detected in the range from 40 μJ to 30 mJ during a surgery. This result indicates that the method studied can be used to detect the spread UVR. (authors)

  11. Thermoluminescence characterization of CVD diamond film exposed to UV and beta radiation

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) properties of diamond films grown by microwave and hot filament CVD techniques were studied. The main purpose of the present work was to characterize the thermoluminescence response of diamond films to ultraviolet and beta radiation. The thermoluminescence excitation spectrum exhibits maximum TL efficiency around 210-215 nm. All samples presented a glow curve composed of at least one TL peak and showed regions of linear as well as supralinear behavior as a function or irradiation dose. The linear dose dependence was found for up to sixteen minutes of monochromatic UV irradiation and 300 Gy for beta irradiated samples. The activation energy and the frequency factor were determined and found in the range of 0.33-1.7 eV and 5.44 x 102-5.67 x 1016 s-1, respectively. The observed TL performance is reasonable appropriate to justify further investigation of diamond films as radiation dosimeters keeping in mind that diamond is an ideal TL dosemeter since it is tissue-equivalent and biological compatible. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. 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.

  13. Hyperfine structure and isotope shift of transitions in Yb I using UV and deep-UV cw laser light and the angular distribution of fluorescence radiation

    International Nuclear Information System (INIS)

    Using the third harmonic of a cw titanium:sapphire laser, the hyperfine structure (HFS) and isotope shift (IS) of three deep-UV transitions of neutral Yb have been measured for the first time. By exploiting the angular distribution of fluorescence radiation, accurate and complete results are obtained for the HFS and IS of the 398.8 nm transition of Yb. From the measured data, normal and specific mass shift as well as field shift values for all transitions considered have been derived. (author)

  14. Changes of proteins in the Antarctic ice microalga Chlamydomonas sp. cultured under UV-B radiation stress

    Institute of Scientific and Technical Information of China (English)

    KAN Guangfeng; MIAO Jinlai; SHI Cuijuan; LI Guangyou

    2006-01-01

    Antarctic ice microalga Chlamydomonas sp. can thrive undisturbed under high UV radiation in the Antarctic ice layer. However, it is unknown that the initial adaptation mechanisms in protein level occurring in response to high UV radiation. Global-expression profiling of proteins in response to stress was analyzed by two-dimensional electrophoresis (2-DE) and image analysis. In the 2-DE analysis,protein preparation is the key step. Three different protein extract methods were compared, and the results showed that the trichloroacetic acid (TCA)-acetone fractional precipitation method was the fittest one. At the same time, the proteins in Chlamydomonas sp. were compared in 2-DE way, and the synthesis of seven protein spots was found disappeared and 18 decreased after exposed to UV-B radiation. In addition, 14 protein spots were enhanced or induced, among which two new peptides (20 and 21 kDa) appeared whose isoelectric point (pI) was 7.05 and 4.60 respectively. These changed proteins might act as key role in the acclimation of Antarctic ice microalga to UV-B radiation

  15. Multilevel UV-B Attenuance : Morphological and Chemical Adaptations of Vicia faba to Ultraviolet-B Radiation

    NARCIS (Netherlands)

    Meijkamp, B.B.

    2006-01-01

    Due to anthropogenic reduction of stratospheric ozone, levels of potentially harmful solar UV-B radiation (280-315 nm) have been increasing on earth during the last three decades. The main aim of this thesis was to study growth responses and morphological and chemical adaptation mechanisms to harmf

  16. Dependence of biologically active UV radiation on the atmospheric ozone in 2000 - 2001 over Stara Zagora, Bulgaria

    International Nuclear Information System (INIS)

    This study investigates how the changes in simultaneously measured ozone columns influence the biologically active UV irradiance. Spectral ground-based measurements of direct solar ultraviolet radiation performed at Stara Zagora (42oN, 25oE), Bulgaria in 2000 - 2001 are used in conjunction with the total ozone content to investigate the relation to the biologically active UV radiation, depending on the solar zenith angle (SZA) and the ozone. The device measures the direct solar radiation in the range 290 - 360 nm at 1 nm resolution. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained as the integral in the wavelength interval between 290 and 330 nm of the UV solar spectrum weighted with an action spectrum, typical of each effect. For estimation of the sensitivity of biological doses to the atmospheric ozone we calculate the radiation amplification factor (RAF) defined as the percentage increase in the column amount of the atmospheric ozone. The biological doses increase significantly with the decrease of the SZA. The doses of SZA=20o are about three times larger than doses at SZA=50o. The RAF derived from our spectral measurements shows an increase of RAF along with the decreasing ozone. For example, the ozone reduction by 1% increases the erythemal dose by about 2%. (authors)

  17. 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 (S

  18. Responses of membrane lipid peroxidation and endogenous hormones of soybean seedlings to UV-B radiation and rare earth

    International Nuclear Information System (INIS)

    [Objective] The aim was to provide strategies for development of rare earth and control of environmental pollution. [Method] Responses of membrane lipid peroxidation and endogenous hormones of soybean seedlings to UV-B radiation and rare earth were studied through hydroponics in laboratory. [Result] The results showed that under irradiation of UV-B(T1-0.15 W/m2 and T2-0.45 W/m2), chlorophyll and indole-3-acetic acid(IAA) contents firstly decreased during the stress phase (1-5d) and then increased during the restoration phase (6-9d) while contents of malonadialdehyde(MDA) and abscisic acid(ABA) gradually increased during the imposition of UV-B radiation (1-5d) and subsequently decreased during recovery from UV-B stress (6-9d) . With adding of La (Ⅲ) with the concentration of 20mg•L-1, the decline/rise trend of chlorophyll, IAA, MDA and ABA contents was slowed down during the stress period while the rise/decline speed was accelerated during the recovery period. [Conclusion] It suggests that the regulation of La (Ⅲ) on membrane lipid peroxidation and endogenous hormones could increase chlorophyll and IAA contents, improve the metabolism of reactive oxygen species (ROS), inhibit membrane lipid peroxidation, decrease the accumulation amount of ABA and alleviate injury of UV-B radiation to soybean seedlings. Further, the protective potential of La (Ⅲ) was better under low UV-B radiation than under high one

  19. Effect of UV Radiation and Evaluated CO2 on Morphological Traits, Yield and Yield Components of Canola (Brassica napus L. Grown under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    Hamid Reza TOHIDI MOGHADAM

    2011-05-01

    Full Text Available In this study, we studied the combined effects of UV radiation, CO2 and water stress on the morphological traits, yield and yield components of canola (Brassica napus cv. �Okapi� and �Talaye� under twelve growth conditions: complete irrigation with ambient CO2 with UV-A (control, complete irrigation with ambient CO2 with UV-B, complete irrigation with ambient CO2 with UV-C, limited irrigation with ambient CO2 with UV-A, limited irrigation with ambient CO2 with UV-B, limited irrigation with ambient CO2 with UV-C, complete irrigation with elevated CO2 with UV-A, complete irrigation with elevated CO2 with UV-B, complete irrigation with elevated CO2 with UV-C, limited irrigation with elevated CO2 with UV-A, limited irrigation with elevated CO2 with UV-B and limited irrigation with elevated CO2 with UV-C. The results showed that water stress significantly decreased all of traits except for the oil percentage. Additionally, an elevated level of CO2 significantly increased the final yield, 1000-seed weight, oil yield, plant height, specific leaf area and number of branches per plant, whereas UV radiation decreased all of the traits in this experiment. Elevated CO2 ameliorated the adverse effects of UV radiation in the final yield, seed weight, oil percentage, oil yield, plant height, specific leaf area and number of branches per plant. This study showed that elevated CO2 can partially ameliorate some of the adverse effects of UV radiation in canola plants. Furthermore, in this study, we observed that the increase in the yield was due to the increase in the seed weight and number of branches caused by elevated CO2 in canola plants. In addition, the maximum yield was obtained from the �Talaye� cultivar under conditions of sunlight, full irrigation and elevated CO2.

  20. Interaction of Radiation Therapy With Molecular Targeted Agents

    OpenAIRE

    Morris, Zachary S.; Harari, Paul M.

    2014-01-01

    The development of molecular targeted therapeutics in oncology builds on many years of scientific investigation into the cellular mechanics of malignant transformation and progression. The past two decades have brought an accelerating pace to the clinical investigation of new molecular targeted agents, particularly in the setting of metastatic disease. The integration of molecular targeted agents into phase III clinical trial design has lagged in the curative treatment setting, particularly i...

  1. DNA repair synthesis in human skin exposed to ultraviolet radiation used in PUVA (psoralen and UV-A) therapy for psoriasis

    International Nuclear Information System (INIS)

    The ultraviolet radiation used in psoralen and UV-A (PUVA) therapy stimulated DNA repair activity in normal human skin and in the uninvolved skin from psoriatic patients. The activity detected by autoradiography increased linearly with exposure time. No stimulation was observed when the UV-B component was removed from the incident radiation by filtration through glass. Therefore UV-B damage to DNA was found responsible for the activity detected following exposure to the unfiltered PUVA light source. (author)

  2. Characterization of biologically effective UV radiation at mid-latitudes sites: innovative method for the calculation of the human vitamin D exposure

    OpenAIRE

    Modesti, Sarah

    2012-01-01

    The Italian territory has the potential for receiving high solar ultraviolet (UV) doses during most of the year. This may represent a serious hazard for human health as UV radiation is responsible for skin cancer: Italy is in the third place, after Australia and USA, for melanoma occurrences. It ought to be remember that UV radiation has well-established beneficial effects on the skin, most notably the synthesis of vitamin D3. However a climatological characterization of biologically effecti...

  3. Photosynthesis damage and protective pigments in plants from a latitudinal arctic/alpine gradient exposed to supplemental UV-B radiation in the field

    International Nuclear Information System (INIS)

    Arctic and alpine plants grown from seed collected from different locations along a latitudinal gradient were studied to determine if populations inhabiting different solar UV-B radiation environments would show differential photosynthetic inhibition under supplemental UV-B irradiation in the field. In general, plants collected from equatorial, alpine sites where solar UV-B irradiance is high, showed no UV-B induced damage of either light-saturated or light-limited photosynthesis, as measured by intact-leaf gas exchange. Photosynthetic inhibition was detected in some but not all ecotypes or species collected from higher latitude locations where effective UV-B irradiance is lower. When exposed to supplemental UV-B irradiation under a full solar spectrum in the field, significant accumulation of UV-absorbing leaf pigments occurred only in populations from higher latitudes. Most alpine populations were apparently protected from UV-B damage without additional pigment accumulation, whereas increased pigment levels did not necessarily act to completely protect populations from higher latitudes. Photosynthesis damage in these species was also not related to leaf weight/leaf area ratios. These results provide additional corroborative evidence for the existence of an appreciable latitudinal gradient in UV-B radiation but suggest that the variation in UV-B sensitivity within and between species cannot be attributed solely to differences in the shielding of UV-B radiation by UV-absorbing leaf pigments and/or leaf structure

  4. Effects of Contamination, UV Radiation, and Atomic Oxygen on ISS Thermal Control Materials

    Science.gov (United States)

    Visentine, Jim; Finckenor, Miria; Zwiener, Jim; Munafo, Paul (Technical Monitor)

    2001-01-01

    Thermal control surfaces on the International Space Station (ISS) have been tailored for optimum optical properties. The space environment, particularly contamination, ultraviolet (UV) radiation, and atomic oxygen (AO) may have a detrimental effect on these optical properties. These effects must be quantified for modeling and planning. Also of interest was the effect of porosity on the reaction to simulated space environment. Five materials were chosen for this study based on their use on ISS. The thermal control materials were Z-93 white coating, silverized Teflon, chromic acid anodized aluminum, sulfuric acid anodized aluminum, and 7075-T6 aluminum. Some of the samples were exposed to RTV 560 silicone; others were exposed to Tefzel offgassing products. Two samples of Z-93 were not exposed to contamination as clean "controls". VUV radiation was used to photo-fix the contaminant to the material surface, then the samples were exposed to AO. All samples were exposed to 1000 equivalent sun-hours (ESH) of vacuum ultraviolet radiation (VUV) at the AZ Technology facility and a minimum of 1.5 x 10(exp 20) atoms/sq cm of AO at Marshall Space Flight Center. Half of the samples were exposed to an additional 2000 ESH of VUV at Huntington Beach prior to sent to AZ Technology. Darkening of the Z-93 white coating was noted after VUV exposure. AO exposure did bleach the Z-93 but not back to its original brightness. Solar absorptance curves show the degradation due to contamination and VUV and the recovery with AO exposure. More bleaching was noted on the Tefzel-contaminated samples than with the RTV-contaminated samples.

  5. 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

  6. Radiation hardenable impregnating agents for the consolidating conservation of wooden objects

    International Nuclear Information System (INIS)

    Radiation hardenable impregnating agents offer some advantages over the conventional agents. At the author's institution objects up to 110 cm length can be impregnated for conservation. More than 200 monomers and resins have been investigated. The procedure of impregnation is outlined and some kinds of wooden objects conserved in this way listed. (G.W.)

  7. 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.

  8. Use of gamma and UV radiation in grafting hydrogel polymers to membranes

    International Nuclear Information System (INIS)

    Full text: Dimethylacrylamide and N-isopropylacrylamide hydrogels are useful for their ability to absorb large amounts of water and for their thermotropic response. However as membranes they do not have the mechanical properties to be applicable in industry. Therefore these hydrogels have been grafted to polyvinylidinedifluoride (PVDF) membranes using radiation. Both UV and gamma irradiation were used. In the first method the PVDF membranes were first hydroxylated by immersion in a aqueous solution of potassium peroxydisulfate (10% w/v), with nitrogen purging for two hours at 80 deg C. This was followed by immersion in an aqueous solution of riboflavine (4mg/L) and monomer (10% v/v), degassing with nitrogen and irradiation under a Mercury UV light (wavelength 240 nm) at room temperature for 15 minutes. Membranes were washed by soxhlet extraction in distilled water and oven dried. The second method of grafting hydrogels to membranes involved immersing the membrane in 10 mL of distilled water containing monomer and CuSO4 to prevent homopolymerisation. The solution was degassed with N2 for 3 minutes then irradiated under nitrogen using a 60Co source for various time periods. The effect of varying monomer and CuSO4 concentration as well as dose rate and dose were studied. Membranes were rinsed in distilled water for 24 hours and dried in an oven before characterisation. Grafting was characterised by mass change (Mettler AC 100 balance), XPS (PHI Model 560 XPS/SAM/SIMA1 multitechnique surface analysis system), SEM (Hitachi S-900 Field Emission SEM) and FTIR-ATR (Perkn Elmer System 2000 FTIR with MIRMCT detector)

  9. Accelerated induction of skin cancers by ultraviolet radiation in hairless mice treated with immunosuppressive agents

    International Nuclear Information System (INIS)

    An increased incidence of cancer is well recognized in organ transplant recipients treated with immunosuppressive agents. Skin cancers are the most common lesions encountered. To investigate a possible relationship between the immunosuppressive agents and ultraviolet radiation (UVR), several groups of hairless mice were treated with ultraviolet light, azathioprine, or prednisone, or the three in various combination. The two latter drugs are the immunosuppressive agents most frequently used in organ transplant recipients

  10. Accelerated induction of skin cancers by ultraviolet radiation in hairless mice treated with immunosuppressive agents

    Energy Technology Data Exchange (ETDEWEB)

    Koranda, F.C.; Loeffler, R.T.; Koranda, D.M.; Penn, I.

    1975-01-01

    An increased incidence of cancer is well recognized in organ transplant recipients treated with immunosuppressive agents. Skin cancers are the most common lesions encountered. To investigate a possible relationship between the immunosuppressive agents and ultraviolet radiation (UVR), several groups of hairless mice were treated with ultraviolet light, azathioprine, or prednisone, or the three in various combination. The two latter drugs are the immunosuppressive agents most frequently used in organ transplant recipients.

  11. Responses of phylloplane yeasts to UV-B (290-320 nm) radiation: interspecific differences in sensitivity

    International Nuclear Information System (INIS)

    The sensitivity to UV-B (290–320 nm) radiation of common phylloplane yeasts from two contrasting UV-B environments was compared in the laboratory using mixtures of white light (PAR: 400–700 nm) and UV-B radiation from artificial lamp sources. Sporidiobolus salmonicolor, Rhodotorula mucilaginosa and Cryptococcus sp., the dominant yeasts on leaves of tea (Camellia sinensis), were isolated in Sri Lanka (SL), while Sporidiobolus sp. and Bullera alba, dominant on faba bean (Vicia faba), were isolated in the U.K. Dose responses were determined separately for each yeast. UV-B reduced colony forming units (due to cell mortality or inactivation) and colony size (due to reduced multiplication) of all yeasts. The LD50 values and doses causing 50% reduction of cells per colony were higher for SL isolates than U.K. isolates. Results indicated that each yeast is somewhat vulnerable to UV-B doses representative of its natural habitat. The relative insensitivity of SL isolates was shown when SL and U.K. isolates were irradiated simultaneously with the same dose of UV-B. Of the two U.K. yeasts, B. alba was significantly more sensitive than Sporidiobolus sp. to UV-B. Except for R. mucilaginosa from SL, all yeasts demonstrated some photorepair in the presence of white light. White light provided relatively little protection for the U.K. isolate of Sporidiobolus sp. although it allowed increased colony size. The spectral responses of Sporidiobolus sp. (U.K.) and of B. alba (U.K.) were broadly similar. Wavelengths longer than 320 nm had no measurable effect on colony forming units. However, colony survival was significantly reduced at 310 nm and all shorter wavebands. No colonies were counted at 290 nm or below. (author)

  12. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    Directory of Open Access Journals (Sweden)

    S. Tilmes

    2012-08-01

    Full Text Available The impact of very short-lived (VSL halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UVERY rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UVERY increases due to declines in ozone column are nearly balanced by reductions of UVERY due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UVERY of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  13. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita

    2016-03-01

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

  14. Low dose UV and gamma radiation on storage rot and physicochemical changes in peaches

    International Nuclear Information System (INIS)

    Peach fruit were irradiated with 7.5 x 10(4) ergs/mm(2) of UV (254nm) or 0.1 kGy gamma rays or a combination of both, then stored at 16C for 21 days. The results showed that both UV and gamma rays reduced storage rot and delayed ripening. UV treated peaches had lower sugar concentration, total phenols, anthocyanins and lower weight loss than the gamma treated peaches. The combination of UV and gamma showed no advantage over the use of UV or gamma alone

  15. Cadmium telluride quantum dots (CdTe-QDs and enhanced ultraviolet-B (UV-B radiation trigger antioxidant enzyme metabolism and programmed cell death in wheat seedlings.

    Directory of Open Access Journals (Sweden)

    Huize Chen

    Full Text Available Nanoparticles (NPs are becoming increasingly widespread in the environment. Free cadmium ions released from commonly used NPs under ultraviolet-B (UV-B radiation are potentially toxic to living organisms. With increasing levels of UV-B radiation at the Earth's surface due to the depletion of the ozone layer, the potential additive effect of NPs and UV-B radiation on plants is of concern. In this study, we investigated the synergistic effect of CdTe quantum dots (CdTe-QDs, a common form of NP, and UV-B radiation on wheat seedlings. Graded doses of CdTe-QDs and UV-B radiation were tested, either alone or in combination, based on physical characteristics of 5-day-old seedlings. Treatments of wheat seedlings with either CdTe-QDs (200 mg/L or UV-B radiation (10 KJ/m(2/d induced the activation of wheat antioxidant enzymes. CdTe-QDs accumulation in plant root cells resulted in programmed cell death as detected by DNA laddering. CdTe-QDs and UV-B radiation inhibited root and shoot growth, respectively. Additive inhibitory effects were observed in the combined treatment group. This research described the effects of UV-B and CdTe-QDs on plant growth. Furthermore, the finding that CdTe-QDs accumulate during the life cycle of plants highlights the need for sustained assessments of these interactions.

  16. Dietary proanthocyanidins inhibit UV radiation-induced skin tumor development through functional activation of the immune system.

    Science.gov (United States)

    Katiyar, Santosh K

    2016-06-01

    The incidence of skin cancer is equivalent to the incidence of malignancies in all other organs combined. The main risk factor for this disease is overexposure of the skin to solar ultraviolet (UV) radiation. UV irradiation induces inflammation, oxidative stress, DNA damage, and suppression of the immune system in the skin, which together contribute to carcinogenesis. The use of dietary phytochemicals shows great promise as a complementary and alternative strategy for skin cancer prevention. Grape seed proanthocyanidins (GSPs) have been tested extensively for their anti-skin cancer effect using in vivo animal models. Supplementation of an AIN76A control diet with GSPs (0.2 and 0.5%, w/w) significantly inhibits UV radiation-induced skin tumor development as well as malignant transformation of papillomas to carcinoma in mice. The inhibition of UVB-induced skin tumor development by GSPs is mediated through interrelated mechanisms of action including: (i) inhibition of inflammation, (ii) rapid repair of damaged DNA, and (iii) stimulation of immune system. Additionally, the chemopreventive effects of GSPs involve DNA repair-dependent functional activation of antigen-presenting cells and stimulation of CD8(+) effector T cells. These effects of GSPs could be useful in attenuation of the adverse effects of UV radiation and may have health benefits in humans. PMID:26991736

  17. MEASUREMENT OF SURFACE SOLAR UV-B RADIATION AT TROPICAL COASTAL STATION BAKKHALI IN WEST BENGAL, INDIA

    Directory of Open Access Journals (Sweden)

    R. BHATTACHARYA

    2012-08-01

    Full Text Available Surface solar ultraviolet irradiance has been measured at Bakkhali (21.8ºN, 87.8ºE, a tropical rural station on the coast of Bay of Bengal, India in West Bengal. The measurements show a remarkable variation in UV-B load exists with a peak value at noon. The blockage of direct UV radiation in mangrove forest of costal site appears low when compared with UV load beneath the multiple trees of Mangifera indica in an inland site of Kalyani (22058' N, 88028' E, West Bengal. Mangrove forests have great potential to act as a natural barrier to natural hazards like cyclone, sea rise, floods, storms etc. and save the flora and fauna from the harmful component of solar ultraviolet radiation. Moreover the forest keeps ecological balance. But with the increase of urbanization this wonder land is under threat. Hence there is a need to monitor solar ultraviolet radiation and optimize the increase of land cover by trees to get maximum benefit. This paper has provided quantitative data of UV irradiance both in open sky and beneath the trees of coastal area.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  19. Synergism in mutations induction in Tradescantia by plants protection agents acting jointly with ionizing radiation

    International Nuclear Information System (INIS)

    Tradescantia was first treated by plants protection agents such as: Ambusz, Afalton, Ripcord, Decis, deltametryne and after that irradiated with X radiation. The synergism of both factors was observed. The mutation frequency dependence on radiation doses was studied. 7 figs., 4 refs. (A.S.)

  20. Functional changes of man erythrocyte surface in the norm and pathology following UV-radiation of various spectral content

    International Nuclear Information System (INIS)

    UV radiation (UVR) of different wavelengths causes immediate increase in the expression of membrane antigenes (EMA) of erythrocytes (Er) in systems ABO and Rhesus in donors, persons with surgical and gynecologic pathologies, but not in leukosis patients. The same effect is recorded for patients with surgical pathology in the process and after treatment with autotransfusion of UV-irradiated blood. Direct stimulation of EMA Er after UVR action is conditioned by partial destruction of external near the membrane layer of Er, by desorption of its components and baring of antigenic determinations. The absence of the effect is related to structural anomaly in Er surface in leukosis patients

  1. Is ultraviolet radiation a synergistic stressor in combined exposures? The case study of Daphnia magna exposure to UV and carbendazim

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Fabianne, E-mail: fabianne@ua.pt [Department of Biology and Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro (Portugal); Ferreira, Nuno C.G.; Ferreira, Abel; Soares, Amadeu M.V.M.; Loureiro, Susana [Department of Biology and Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro (Portugal)

    2011-03-15

    The toxicological assessment of chemical compounds released to the environment is more accurate when mixtures of chemicals and/or interactions between chemicals and natural stressors are considered. Ultraviolet radiation can be taken as a natural stressor since the levels of UV are increasing due to the decrease of its natural filter, the stratospheric ozone concentration. Therefore, a combination of chemical exposures and increasing UV irradiance in aquatic environments is likely to occur. In the current study, combined effects of carbendazim and ultraviolet radiation were evaluated, using selected life traits as endpoints on Daphnia magna. To design combined exposures, first single chemical and natural stressor bioassays were performed: a reproduction test with carbendazim and a reproduction, feeding inhibition and Energy budget test with ultraviolet radiation. Following single exposures, the combinations of stressors included exposures to UV radiation and carbendazim for a maximum exposure time of 4 h, followed by a post-exposure period in chemically contaminated medium for a maximum of 15 days, depending on the endpoint, where the effects of the combined exposures were investigated. Statistical analyses of the data set were performed using the MixTox tool and were based on the conceptual model of Independent Action (IA) and possible deviations to synergism or antagonism, dose-ratio or dose-level response pattern. Both ultraviolet radiation and carbendazim as single stressors had negative impacts on the measured life traits of daphnids, a decrease on both feeding rates and reproduction was observed. Feeding rates and reproduction of D. magna submitted to combined exposures of ultraviolet radiation and carbendazim showed a dose-ratio deviation from the conceptual model as the best description of the data set, for both endpoints. For feeding inhibition, antagonism was observed when the UV radiation was the dominant item in combination, and for reproduction

  2. Is ultraviolet radiation a synergistic stressor in combined exposures? The case study of Daphnia magna exposure to UV and carbendazim

    International Nuclear Information System (INIS)

    The toxicological assessment of chemical compounds released to the environment is more accurate when mixtures of chemicals and/or interactions between chemicals and natural stressors are considered. Ultraviolet radiation can be taken as a natural stressor since the levels of UV are increasing due to the decrease of its natural filter, the stratospheric ozone concentration. Therefore, a combination of chemical exposures and increasing UV irradiance in aquatic environments is likely to occur. In the current study, combined effects of carbendazim and ultraviolet radiation were evaluated, using selected life traits as endpoints on Daphnia magna. To design combined exposures, first single chemical and natural stressor bioassays were performed: a reproduction test with carbendazim and a reproduction, feeding inhibition and Energy budget test with ultraviolet radiation. Following single exposures, the combinations of stressors included exposures to UV radiation and carbendazim for a maximum exposure time of 4 h, followed by a post-exposure period in chemically contaminated medium for a maximum of 15 days, depending on the endpoint, where the effects of the combined exposures were investigated. Statistical analyses of the data set were performed using the MixTox tool and were based on the conceptual model of Independent Action (IA) and possible deviations to synergism or antagonism, dose-ratio or dose-level response pattern. Both ultraviolet radiation and carbendazim as single stressors had negative impacts on the measured life traits of daphnids, a decrease on both feeding rates and reproduction was observed. Feeding rates and reproduction of D. magna submitted to combined exposures of ultraviolet radiation and carbendazim showed a dose-ratio deviation from the conceptual model as the best description of the data set, for both endpoints. For feeding inhibition, antagonism was observed when the UV radiation was the dominant item in combination, and for reproduction

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

    International Nuclear Information System (INIS)

    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

  4. 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.

  5. 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. PMID:25763657

  6. Mass spectrometry data from proteomic analysis of human skin keratins after exposure to UV radiation.

    Science.gov (United States)

    Lee, Seon Hwa; Matsushima, Keita; Miyamoto, Kohei; Oe, Tomoyuki

    2016-06-01

    A mass spectrometry (MS)-based proteomic methodology was employed to monitor oxidative modifications in keratins, the main constituents of human skin ("Non-invasive proteomic analysis of human skin keratins: screening of methionine oxidation in keratins by mass spectrometry" [1], "UV irradiation-induced methionine oxidation in human skin keratins: mass spectrometry-based non-invasive proteomic analysis" [2]). Human skin proteins were obtained non-invasively by tape stripping and solubilized in sodium dodecyl sulfate (SDS) buffer, followed by purification and digestion using the filter-aided sample preparation method. The tryptic peptides were then analyzed by liquid chromatography (LC)/electrospray ionization (ESI)-MS, tandem MS (MS/MS), and LC/ESI-selected reaction monitoring (SRM)/MS. The MS/MS data were generated to confirm amino acid sequences and oxidation sites of tryptic peptides D(290)VDGAYMTK(298) (P1) and N(258)MQDMVEDYR(267) (P2), which contain the most susceptible oxidation sites (Met(259), Met(262), and Met(296) in K1 keratin) upon UVA irradiation [2]. Subsequently, quantitative determination of the relative oxidation levels of P1 and P1 [2] was achieved by LC/ESI-SRM/MS analyses of P1 and P2 together with their oxidized forms after exposure to UVA radiation or treatment with hydrogen peroxide (H2O2). PMID:26958637

  7. Mass spectrometry data from proteomic analysis of human skin keratins after exposure to UV radiation

    Directory of Open Access Journals (Sweden)

    Seon Hwa Lee

    2016-06-01

    Full Text Available A mass spectrometry (MS-based proteomic methodology was employed to monitor oxidative modifications in keratins, the main constituents of human skin (“Non-invasive proteomic analysis of human skin keratins: screening of methionine oxidation in keratins by mass spectrometry” [1], “UV irradiation-induced methionine oxidation in human skin keratins: mass spectrometry-based non-invasive proteomic analysis” [2]. Human skin proteins were obtained non-invasively by tape stripping and solubilized in sodium dodecyl sulfate (SDS buffer, followed by purification and digestion using the filter-aided sample preparation method. The tryptic peptides were then analyzed by liquid chromatography (LC/electrospray ionization (ESI-MS, tandem MS (MS/MS, and LC/ESI-selected reaction monitoring (SRM/MS. The MS/MS data were generated to confirm amino acid sequences and oxidation sites of tryptic peptides D290VDGAYMTK298 (P1 and N258MQDMVEDYR267 (P2, which contain the most susceptible oxidation sites (Met259, Met262, and Met296 in K1 keratin upon UVA irradiation [2]. Subsequently, quantitative determination of the relative oxidation levels of P1 and P1 [2] was achieved by LC/ESI-SRM/MS analyses of P1 and P2 together with their oxidized forms after exposure to UVA radiation or treatment with hydrogen peroxide (H2O2.

  8. Microcolony formation by single-cell Synechococcus strains as a fast response to UV radiation.

    Science.gov (United States)

    Callieri, Cristiana; Lami, Andrea; Bertoni, Roberto

    2011-11-01

    UV radiation (UVR) has different effects on prokaryotic cells, such as, for instance, filamentation and aggregation in bacteria. Here we studied the effect of UVR on microcolony formation in two freshwater Synechococcus strains of different ribotypes (group B and group I) and phycobiliprotein compositions (phycoerythrin [PE] and phycocyanin [PC]). Each strain was photoacclimated at two light intensities, low light (LL) (10 μmol m⁻² s⁻¹) and moderate light (ML) (100 μmol m⁻² s⁻¹). The cultures were exposed for 6 days to treatments with UVR or without UVR. PE-rich Synechococcus acclimated to LL had a low carotenoid/chlorophyll a (car/chl) ratio but responded faster to UVR treatment, producing the highest percentages of microcolonies and of cells in microcolonies. Conversely, the same strain acclimated to ML, with a higher car/chl ratio, did not aggregate significantly. These results suggest that microcolony formation by PE-rich Synechococcus is induced by UVR if carotenoid levels are low. PC-rich Synechococcus formed a very low percentage of microcolonies in both acclimations even with low car/chl ratio. The different responses of the two Synechococcus strains to UVR depend on their pigment compositions. On the other hand, this study does not exclude that UVR-induced microcolony formation could also be related to specific ribotypes. PMID:21890666

  9. The therapeutic efficiency of nucleotides and nucleosides in UV radiation edema of mice

    International Nuclear Information System (INIS)

    The influence of several nucleotides and nucleosides on UV radiation edemas of mice was studied with the aid of a staining test. In the first test series, amounts equimolar to 20 mg thymidine were injected i.p. It was found that thymidine, ATP, ADP and A5'MP had a significant influence which uridine did not have. The NAD dose of 54.8 mg was lethal in all 10 animals and the ATP dose of 42 mg in three out of 10 animals, while ADP and A5'MP had the effect of a reversible retardation of movements. The most effective substances of this series were ATP and ADP. In the second test series, the substances were equimolar to 1.8 mg thymidine. All substances tested, i.e. thymidine, adenosin, adenosin-cyclophosphate, NAD, NADH, ATP, ADP and A5'MP had a significant effect. Except for NAD, to which the animals reacted with a slight retardation, all substances were well tolerated. NAD and ADP were the most effective. In a third test series, dose-efficiency curves were established for thymidine and ATP. ATP was significantly more effective in equimolar doses. This finding is discussed. (orig.)

  10. Reconstruction of daily erythemal UV radiation values for the last century - The benefit of modelled ozone

    Science.gov (United States)

    Junk, J.; Feister, U.; Rozanov, E.; Krzyścin, J. W.

    2013-05-01

    Solar erythemal UV radiation (UVER) is highly relevant for numerous biological processes that affect plants, animals, and human health. Nevertheless, long-term UVER records are scarce. As significant declines in the column ozone concentration were observed in the past and a recovery of the stratospheric ozone layer is anticipated by the middle of the 21st century, there is a strong interest in the temporal variation of UVER time series. Therefore, we combined groundbased measurements of different meteorological variables with modeled ozone data sets to reconstruct time series of daily totals of UVER at the Meteorological Observatory Potsdam, Germany. Artificial neural networks were trained with measured UVER, sunshine duration, the day of year, measured and modeled total column ozone, as well as the minimum solar zenith angle. This allows for the reconstruction of daily totals of UVER for the period from 1901 to 1999. Additionally, analyses of the long-term variations from 1901 until 1999 of the reconstructed, new UVER data set are presented. The time series of monthly and annual totals of UVER provide a long-term meteorological basis for epidemiological investigations in human health and occupational medicine for the region of Potsdam and Berlin. A strong benefit of our ANN-approach is the fact that it can be easily adapted to different geographical locations, as successfully tested in the framework of the COSTAction 726.

  11. Combined effects of elevated UV-B radiation and the addition of selenium on common (Fagopyrum esculentum Moench) and tartary [Fagopyrum tataricum (L.) Gaertn.] buckwheat

    International Nuclear Information System (INIS)

    Plants of Fagopyrum esculentum and Fagopyrum tataricum grown outdoors under three levels of UV-B radiation were studied for 9 weeks, from sowing to ripening. At week 7 they were sprayed with Se solution (1 g/cubic m). Morphological, physiological, and biochemical parameters of the plants were monitored. Elevated UV-B radiation, corresponding to a 17% reduction of the ozone layer, induced synthesis of UV absorbing compounds. In both species it caused a reduction in amounts of chlorophyll a during the time of intensive growth. This effect was increased in tartary buckwheat in the presence of Se. The respiratory potential was lower in plants subjected to enhanced UV-B radiation during the time of intensive growth. The effective quantum yield of photosystem 2 was also reduced in both species and was mitigated by the addition of Se. Se also mitigated the stunting effect of UV-B radiation and the lowering of biomass in common buckwheat

  12. Epidermal transmittance and phenolic composition in leaves of atrazine-tolerant and atrazine-sensitive cultivars of Brassica napus grown under enhanced UV-B radiation

    International Nuclear Information System (INIS)

    Experiments were conducted on the atrazine-tolerant mutant Stallion and the atrazine-sensitive cv. Paroll of Brassica napus L., which were grown under either visible light or with the addition of UV-B radiation (280–320 nm) for 15 days. The mutant has been shown to be sensitive to high levels of visible light as compared to the atrazine-sensitive cultivar and therefore we wished to determine plant response to UV-B radiation with respect to potential pigment changes, certain anatomical features, radiation penetration and partial photosynthesis. With regard to pigment changes, we were particularly interested in whether the compositional shift in flavonol pigments under enhanced UV-B radiation, previously suggested to favour increased antioxidant activity, is confined to the adaxial epidermis, which generally receives most UV-B radiation or whether the pigment shift is also inducible in the abaxial epidermis.As was to be expected, the penetration of UV-B radiation (310 nm) was lower in the UV-B-exposed plants, which was correlated with an increased amount of UV-screening pigments in the adaxial and abaxial epidermal layers. The main flavonoid glycosides showed the largest shift from kaempferol to quercetin as aglycone moiety in the adaxial epidermal layer. However, in the abaxial epidermal layer the hydroxycinnamic acid (HCA) derivatives and kaempferol glycosides were predominant. Penetration of 430 nm light was higher after UV-B exposure, and probably contributed to the fact that photosynthetic efficiency of photosystem II was unchanged or higher after UV-B exposure. UV-B radiation decreased leaf area in the atrazine-tolerant mutant only. Both cultivars showed an increased leaf thickness after UV-B exposure due to cell elongation mainly of the palisade tissue. This was especially evident in the mutant

  13. Cytogenetic effect of low dose radiation and contrast agent

    International Nuclear Information System (INIS)

    The effect of the X-ray contrast medium Amidotrizoate on radiation-induced chromosomal damage was investigated in peripheral human lymphocytes, in vitro. The blood undergoes treatment in one of three ways: 1) Amidotriozate alone at concentrations 1, 3 and 5%; 2) X-irradiation alone at dose 0,2 Gy; 3) X-irradiation in the presence of the contrast medium. Given alone Amidotrisoate was not effective in producing chromosomal aberrations. The cytogenetic effect of 0,2 Gy X-ray was statistically significant. The presence of Amidotrisoate during irradiation potentiates radiation-induced chromosomal damage depending on the concentration used. (author)

  14. 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. PMID:25704551

  15. 增补UV-B辐射下南亚热带森林建群树种叶片对UV-B辐射的防护%UV-B Screening in Leaves of Constructive Tree Species of Low Subtropical Forest under Supplementary UV-B Radiation

    Institute of Scientific and Technical Information of China (English)

    赵平; 孙谷畴; 曾小平

    2008-01-01

    研究了我国南亚热带森林5种建群树种UV-B辐射诱导的UV-B吸收物质(在280~320 nm波长下测定)的积累及抗UV-B辐射的可能性保护机制.增补UV-B辐射下,马尾松(Pinus massoniana)针叶的甲醇可溶性提取物和细胞壁的碱提取酚类的含量明显高于正常水平的光辐射下.红椎(Castanopsis hystrix)和厚壳桂(Cryptocarya chinensis)叶片的这些化学物质也升高,意味着增补UV-B辐射刺激UV-B辐射吸收物质的生成,形成抗UV-B辐射的功能性保护结构.然而,自然光下已含有大量细胞壁碱提取酚类的荷木(Schima superba)和藜蒴(Castanopsis fissa),这些化合物在增补UV-B辐射下则见下降,很有可能表皮层细胞壁碱提取酚类被转移到含有较低甲醇可溶性色素的液胞可溶性化合物里,这一现象意示着可能涉及叶肉组织光合机构的保护策略.增补UV-B下,马尾松针叶的叶绿素a和b含量不受影响,而其他4种阔叶树叶片则下降10.7% 到16.8%不等.胡萝卜素对增补UV-B辐射的响应变化不一,红椎和荷木的胡萝卜素水平下降,而马尾松、厚壳桂和藜蒴的胡萝卜素则上升,后者也许与功能性增加激发能耗散有关.结果显示,自然条件下不同树种展示出不同的驯化策略以形成抗UV-B辐射增加的防护机制.表4参29%The accumulation of UV-B absorbing materials (measured at the wavelength band of 280~320 nm) induced by UV-B radiation and possible involvement of a protective screening against UV-B radiation were investigated in five constructive species of low subtropical forest in South China. The methanol soluble extracts and alkali-extractable cell wall-bound phendics were significantly higher in needles of Pinus massoniana under supplementary UV-B radiation than under normal level of sunlight. These compounds were also enhanced in leaves of Castanopsis hystrix and Cryptocarya chinensis, implying that the supplementary UV-B radiation stimulated the synthesis

  16. 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

  17. Effect of column ozone on the variability of biologically effective UV radiation at high southern latitudes.

    Science.gov (United States)

    Sobolev, I

    2000-12-01

    Solar irradiance measurements from Ushuaia (Argentina) and Palmer and McMurdo Stations in Antarctica covering four seasons from mid-1993 through early 1997 have been analyzed and their variations compared with column ozone changes. UV irradiances were weighted for biological effectiveness using a published biological weighting function for dose-dependent inhibition of photosynthesis by phytoplankton from the Weddell Sea. All calculations involved integrated daily UV doses and visible exposures (weighted UV and unweighted visible irradiances, respectively). The results show that daily biologically effective total UV doses underwent large short-term variations at all three sites, with day-to-day increases up to 236% at Ushuaia, 285% at Palmer and 99% at McMurdo. Parallel changes in visible exposure indicated that the total UV changes were preponderantly due to variations in cloudiness. On a 12-month basis, daily biologically effective UV doses correlated strongly with visible exposures (R > or = 0.99). Anticorrelations of total UV with ozone, on the other hand, were poor (R > -0.11). The largest daily biologically effective UV doses, and their day-to-day increases, occurred as part of the normal variability related to cloud cover and were seldom associated with significant ozone depletion. UV dose/visible exposure ratios tended to reflect ozone depletion events somewhat more consistently than UV doses alone. With the Weddell Sea phytoplankton weighting function used in this study, antarctic ozone hole events were seldom readily discernible in the biologically effective UV record. The results suggest that, where the UV sensitivity of organisms was similar to that of the Weddell Sea phytoplankton, seasonal ozone depletion had no appreciable effect on annual primary productivity during the 1993-1997 period. Additional data on the geographical and seasonal variation of biological weighting functions are desirable for more comprehensive assessments of ozone depletion

  18. Effect of the Solar UV/EUV Heating on the Intensity and Spatial Distribution of Jupiter's Synchrotron Radiation

    Science.gov (United States)

    Kita, Hajime; Misawa, H.; Tsuchiya, F.; Tao, C.; Morioka, A.

    2012-10-01

    Jupiter's synchrotron radiation (JSR) is the emission from relativistic electrons, and it is the most effective probe for remote sensing of Jupiter's radiation belt from the Earth. Recent observations reveal short term variations of JSR with the time scale of days to weeks. Brice and McDonough (1973) proposed that the solar UV/EUV heating for Jupiter's upper atmosphere causes enhancement of total flux density. If such a process occurs at Jupiter, it is also expected that diurnal wind system produces dawn-dusk asymmetry of the JSR brightness distribution. Preceding studies confirmed that the short term variations in total flux density correspond to the solar UV/EUV. However, the effect of solar UV/EUV heating on the brightness distribution has not been confirmed. Hence, the purpose of this study is to confirm the solar UV/EUV heating effect on total flux density and brightness distribution. We made radio imaging analysis using the National Radio Astronomy Observatory (NRAO) archived data of the Very Large Array (VLA) obtained in 2000, and following results were shown. 1, Total flux density varied corresponding to the solar UV/EUV. 2, Dawn side emission was brighter than dusk side emission almost every day. 3, Variations of the dawn-dusk asymmetry did not correspond to the solar UV/EUV. In order to explain the second result, we estimate the diurnal wind velocity from the observed dawn-dusk ratio by using the model brightness distribution of JSR. Estimated neutral wind velocity is 46+/-11 m/s, which reasonably corresponds to the numerical simulation of Jupiter's upper atmosphere. In order to explain the third result, we examined the effect of the global convection electric field driven by tailward outflow of plasma in Jupiter's magnetosphere. As the result, it is suggested that typical fluctuation of the convection electric field strength was enough to cause the observed variations of the dawn-dusk asymmetry.

  19. Influence of enhanced UV-B radiation on biomass allocation and pigment concentrations in leaves and reproductive structures of greenhouse-grown Brassica rapa

    International Nuclear Information System (INIS)

    We assessed the effects of enhanced ultraviolet-B radiation (UV-B; 280–320 nm) on biomass allocation to roots, shoots, leaves and flowers in the annual Brassica rapa. In addition, we investigated how concentrations of chlorophyll and UV-B-absorbing compounds in leaves, ovaries and pollen changed in response to enhanced UV-B. Plants were grown for 38 d in a greenhouse under lampbanks providing daily biologically effective UV-B doses equivalent to those under ambient mid-March stratospheric ozone levels or 16% (‘low-enhanced UV-B’) or 32% (‘high-enhanced UV-B’) ozone depletion levels for Morgantown, WV, USA. Total and aboveground biomass of plants was less under low-enhanced UV-B, but similar to ambient controls under high-enhanced UV-B. Concentrations of UV-B-absorbing compounds in leaves (area basis) increased under high-enhanced UV-B by about 20%, but were similar to ambient controls under low-enhanced UV-B. More effective protection due to higher screening-compound concentrations in plants under high-enhanced UV-B may explain why biomass production was not reduced. Plants under high-enhanced UV-B also had more reproductive biomass and produced more flowers, and had less root mass, than plants under ambient or low-enhanced UV-B. Concentrations of leaf total chlorophyll were not affected by UV-B treatment. While UV-B treatment had no affect on concentrations of UV-B-absorbing compounds in ovaries, concentrations in pollen from plants under both enhanced-UV-B treatments were >40% greater than ambient controls

  20. 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.

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

    International Nuclear Information System (INIS)

    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

  2. 螺旋藻对短期增强UV-B辐射的生理生化响应%Physiological and biochemical responses of Spirulina platensis to short-term enhanced UV-B radiation

    Institute of Scientific and Technical Information of China (English)

    薛林贵; 石小霞; 褚可成; 陈志梅; 李师翁

    2011-01-01

    The amount of UV-B radiation reaching the earth's surface is increasing due to attenuation of the stratospheric ozone. Although the release of ozone-depleting material has declined significantly in the past decade, there is a considerable lag in the recovery of the ozone layer. Cyanobacteria are the oldest photosynthetic pro-karyotes and play an important role in the aquatic ecosystem. UV-B can penetrate water to a depth sufficient to disrupt aquatic ecosystems. For example, the depth of water required to remove 90% of the solar radiation at 310 nm is about 20 m in the clearest ocean. Thus, a large number of cyanobacteria populate aquatic habitats that are exposed to UV-B radiation. UV-B radiation is known to affect cyanobacteria biomass by disrupting physiological and biochemical processes. However, cyanobacteria have developed mechanisms to counteract the damaging effects of UV-B, including production of UV-screening pigments [(e.g., mycosporine-like amino acids (MAAs)] and downward migration. We evaluated the effects of short-term enhanced UV-B radiation on physiological indices, including photosynthetic pigment content, MDA, MAAs, and proline, in Spirulina platensis. S. Platensis were exposed to 240 μW/cm2UV-B for 3.5 h. By compared with untreated cyanobacteria cells, exposure to increased levels of UV-B radiation was associated with a reduction in chlorophyll a, carotenoid and phycobiliprotein content, with a change in MDA content. Our results suggest that increased levels of UV-B radiation causes bleaching of the photosynthetic pigment. Exposure to higher levels of UV-B was also associated with increased synthesis of MAAs and accumulation of proline. We hypothesize that this is a mitigation strategy to reduce the damaging effects of UV-B.%通过生物化学和对比分析的方法,研究了短期增强UV-B辐射对钝顶螺旋藻(Spirulina platensis)794光合色素、丙二醛(MDA)、类菌孢素氨基酸(MAAs)以及脯氨酸含量的影响.研究结果显

  3. UV-B辐射胁迫下杨梅幼苗的高光谱响应%High-spectral responses of Myrica rubra seedlings to UV-B radiation stress

    Institute of Scientific and Technical Information of China (English)

    金鑫杰; 江洪; 陈健; 时启龙; 张倩倩

    2012-01-01

    A simulated field experiment with three treatments, i. e. , ambient light ( control) , reduced UV-B radiation, and enhanced UV-B radiation, was conducted to evaluate the effects of solar ultraviolet ( UV-B) radiation on the seedlings of Myrica rubra, a typical woody species in subtropical region. The leaf chlorophyll content, spectral reflectance and spectral characteristic parameters were measured and analyzed. As compared with the control, enhanced UV-B radiation decreased the seedling chlorophyll content while reduced UV-B radiation significantly increased the chlorophyll content, and these effects reflected in the spectral reflectance. Under the effects of the three gradients of UV-B radiation, the differences in the reflectance at visible region mainly occurred around the green peak and red edge on the reflectance curve, and the peak wavelength of the red edge shifted to longer wavelength. Enhanced UV-B radiation had an accumulated temporal effect on M. rubra. The inverted-Gaussian model parameters R0, λ0, λp, Rs, and 6 were the useful guides to reveal the spectral responses of M. rubra seedlings under UV-B radiation stress, among which, R8 performed the best. The differences in the spectral reflectance under different UV-B radiation levels could be effectively distinguished with the vegetation indices composed of the spectral reflectance of narrow wave bands or the reflectance at specific wavelengths.%设置UV-B滤光减弱、UV-B辐射增强和自然光(对照)3组模拟大田试验,比较了不同UV-B辐射处理下,亚热带典型木本植物杨梅幼苗的叶绿素含量、光谱反射率及光谱特征参数,研究UV-B辐射变化对亚热带森林树种的影响.结果表明:增强UV-B辐射可降低杨梅幼苗的叶绿素含量,而降低辐射则会显著促进叶绿素的增加,并且这种胁迫反应于光谱反射率中.3种不同梯度UV-B辐射作用下,可见光部分光谱反射率间的差异主要集中在绿光反射峰及红边附近,

  4. Antioxidant Defense Mechanisms in Pseudomonas aeruginosa: Role of Iron-Cofactored Superoxide Dismutase in Response to UV-C Radiations.

    Science.gov (United States)

    Ghorbal, Salma Kloula Ben; Maalej, Lobna; Chourabi, Kalthoum; Khefacha, Sana; Ouzari, Hadda-Imene; Chatti, Abdelwaheb

    2016-08-01

    The role of SOD gene in response to UV-C radiations was studied in Pseudomonas aeruginosa. Firstly, our results showed that the inactivation of sodM and/or sodB genes decreases the resistance of P. aeruginosa after exposure to UV-C rays. Furthermore, our results showed that SOD activity is dose dependant in all strains. However, significant increase in SOD activity was only shown at UV-C exposure time of 5 min in sodB mutant. At an elevated dose equivalent to 30 min of exposure, significant increase in SOD activity was observed in sodM. Catalase activities showed significant decrease in WT and in sodB mutant after an exposure time of 30 min. CAT enzyme was present at higher levels than SOD, reflecting that alternate enzymes such as POX, is poorly associated with CAT activity, and an increase in POX activity is related to increase in stress tolerance. The overall results showed that sodB gene has an important protective role against UV-C radiations in P. aeruginosa, compared to SodM isoform. PMID:27094998

  5. Photosynthetic 14CO2 fixation and [15N]-ammonia assimilation during UV-B radiation of Lithodesmium variabile

    International Nuclear Information System (INIS)

    Uptake of [15N]-ammonia was more sensitive to UV-B exposure than the total 14CO2 fixation rate of Lithodesmium variabile Takano. Short-term UV-B radiation (15 min) had practically no effect on the kinetics of [15N]-ammonia, whereas there was an effect on [14C]-bicarbonate uptake rate. A significant reduction was found after 30 and 60 min UV-B stress. The time course of photosynthetic uptake of 15NH4Cl at several wavelengths was markedly depressed at shorter wavelengths (irradiation with WG 280). A short-term (11 min) exposure to ultraviolet radiation had no influence on the [14C]-labeled photosynthetic products. However, the [15N]-label of several amino acids and the ratio of [15N]-glutamine to [15N]-glutamic acid varied after irradiation with different ultraviolet wavebands. The results are discussed with reference to UV damage to the key enzymes of nitrogen metabolism. (author)

  6. Selective surface functionalization of polystyrene induced by synchrotron or UV radiation in the presence of oxygen or acrylic acid vapors

    International Nuclear Information System (INIS)

    Efficient surface functionalization of Polystyrene (PS) thin films by electromagnetic radiation in combination with a reactive gaseous atmosphere was obtained. Monochromatic synchrotron (SR) or polychromatic UV radiation were used as excitation sources. When SR was used, O2 was introduced after irradiation into the UHV chamber. UV irradiation was carried out keeping a constant flow of O2 or acrylic acid (AA) vapors during the photolysis. FTIR-ATR and XPS-NEXAFS spectra were obtained at the UFRGS and the LNLS, Campinas respectively. PS films were functionalized by monochromatic SR and then expose to O2 at specific transitions such us C 1s →σ*C-C excitation. It was found a high rate of COO, C=O and C-O groups at the surface (> 70%). UV-assisted treatment in the presence of AA vapors showed that an efficient polymerization process took place, such as, it was observed in previous AA low pressure RF plasma treatments. UV-assisted functionalization has the advantage of lower costs and simple set-up compared to plasma treatments. (author)

  7. Risks, especially for the eye, emanating from the rise of solar UV-radiation in the Arctic and Antarctic regions.

    Science.gov (United States)

    Meyer-Rochow, V B

    2000-01-01

    Physical and biological characteristics of solar UV-radiation wavebands A, B, and C are explained and information is provided on UV-levels in particular environments and ocular tissues. The question whether or not the rise in circumpolar UV of the last 20 years or so can be regarded as a threat is briefly addressed and it is concluded that even if no threat to photosynthetic productivity of crops and vegetation exists, there is a danger regarding the status of health of human skin and eyes (in particular the lens). The nature of the UV-induced damage to cornea, lens, and even the retina with its photo-receptive cells and pigment epithelium is assessed and a word of caution is sounded with regard to possible injury-potentiating effects of certain chemicals as seen, for instance, in the recent and alarming rise of cataract in Scottish salmon. Finally, because of the multifaceted effects of UV (e.g. at molecular, cellular, tissue, individual, population, and ecosystem level), a plea is made for a concerted, well-funded, international effort to tackle the many remaining problems at all fronts and from all possible angles. PMID:10850006

  8. Impact of Very Short-lived Halogens on Stratospheric Ozone Abundance and UV radiation in a Geo-engineered Atmosphere

    Science.gov (United States)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R. J.; Canty, T. P.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-12-01

    The impact of BrO from very short-lived (VSL) source species on stratospheric ozone is investigated for a hypothetical geo-engineered atmosphere in 2040, assuming the injection of sulfuric acid aerosols. An estimated amount of stratospheric halogens from VSL sources based on satellite observations, model results and previous studies, result in lower column ozone for nearly all seasons and nearly all latitudes, and up to 4% in summer mid- and high latitudes. Considering an upper limit of VSL sources, the annual increase in surface erythemal UV radiation (UV_ERY) due to the decrease in ozone as a result of geo-engineering is 12% and 6% in southern and northern high latitudes, respectively. The increase of UV_ERY due to a reduction of ozone for low and mid latitudes is balanced by the reduction of UV_ERY due to aerosol scattering, if VSL halogen sources are not considered. However, VSL halogens results in additional ozone depletion and in an increase of UV_ERY of up to 5% in spring and fall in mid- and high latitudes as a result of geo-engineering. This study demonstrates that VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  9. Physiological bases for detecting and predicting photoinhibition of aquatic photosynthesis by PAR and UV radiation

    International Nuclear Information System (INIS)

    Phytoplankton photosynthesis is the basis of almost all aquatic primary production in the world's oceans, estuaries and lakes. Oceanic primary production is a major portion of the global carbon budget (see other contributions this volume). Currently, we are unable to account for all the CO2 that is leaving the atmosphere and debate continues whether the ''missing carbon'' is going into either terrestrial and oceanic sinks (7). In this context, it is important to improve our knowledge of how phytoplankton photosynthesis responds to the aquatic environment. The aquatic light environment is primary among several factors governing aquatic photosynthesis. To understand phytoplankton response to aquatic irradiance, we must consider how light propagates underwater, variations in light spectral quality as well as intensity. Also important is how these optical characteristics relate to processes of light absorption and utilization by phytoplankton cells. Considerable progress has been made on answering many of these questions (e.g. 27). One topic, phytoplankton responses to irradiance stress induced by photosynthetically available radiation (PAR2) and UJV, has become increasingly important. The primary consequence in both cases is a time-dependent loss of photosynthetic activity (photo inhibition). Concern over the effects of solar UV irradiance has recently intensified with the advent of stratospheric ozone depletion, which allows for an increase of the mid-ultraviolet (UVB 280-320 nm)irradiance, especially in the Antarctic. The sensitivity of phytoplankton photosynthesis to irradiance stress can be readily demonstrated (36), however,showing whether this stress actually occurs in the aquatic environment remains difficult. The essential problem is that phytoplankton are in suspension. Their irradiance exposure will be determined by mixing processes that transport cells over a vertical gradient in light availability. The response to irradiance stress

  10. The effect of UV-B radiation enhancement on the interspecific competition between Skeletonema costatum and Heterosigma akashiwo

    Institute of Scientific and Technical Information of China (English)

    XIAO Hui; TANG Xuexi; ZHANG Peiyu; CAI Hengjiang

    2005-01-01

    The responses of the interspecific competition between Skeletonema costatum and Heterosigma akashiwo to UV-B radiation enhancement were studied by the co-culture method. The results showed that Heterosigma akashiwo exhibited inhibition on the growth of Skeletonema costatum, and with the increase of initial inoculation density of Heterosigma akashiwo, heavier inhibition on Skeletonema costatum appeared. Under different inoculation proportions, Heterosigma akashiwo could always be in predominance in competition with Skeletonema costatum. The UV-B radiation treatment could change the competition relationship between Skeletonema costatum and Heterosigma akashiwo, which could increase the competitive dominance of Skeletonema costatum and decrease the competitive dominance of Heterosigma akashiwo. When the inoculation proportions of Heterosigma akashiwo and Skeletonema costatum were H:S=1:4 and H:S=1:1, Skeletonema costatum was in predominance in this competition; however, Heterosigma akashiwo was in predominance when the inoculation proportion was H:S=4:1.

  11. Vitamin C acts as radiation-protecting agent

    International Nuclear Information System (INIS)

    It is well known that vitamin C (L-ascorbic acid) is a very efficient, water soluble antioxidant. Its multifunctional biological and biochemical activities are rather well established in the last few decades (e.g. Sies and Stahl, 1995; Meydani et al., 1995; NRC, 1989. In the present letter we are reporting briefly the pronounced radiation-protecting properties of ascorbate (AH-) observed on bacteria (E. coli AB1157) as well as on cultured cells (SCC VII, eukaryotic cells)

  12. In-vivo models for radiation mitigator agents

    International Nuclear Information System (INIS)

    The US Department of Health and Human Services assigned the National Institute of Allergy and Infectious Diseases (NIAID), National Institute of Health (NIH), with the responsibility to identify, characterize and develop new medical countermeasure (MCM) products against radiological and nuclear attacks that may cause-a public health emergency. MCMs must be developed within the criteria of the U.S. Food and Drug Administration's (FDA) 'animal rule' (AR) which requires the design and conduct of validated animal models to define the major sequelae of the Acute Radiation Syndrome (ARS) and Delayed Effects of Acute Radiation Exposure (DEARE). To this end, the NIAID-funded Product Development Support Services Program has established an ARS/DEARE animal model research platform which includes several basic animal models for hematopoietic and gastrointestinal ARS in the mouse and nonhuman primate (NHP) using total-body irradiation (TBI), whole-thorax lung irradiation (WTLI), or a multi-organ dysfunction model defined by partial-body irradiation with 5% bone marrow sparing (PBI/ BM5). These specific models will be discussed as well as ongoing observational studies NIAID is funding to assess the long-term effects of radiation in NHPs and A-Bomb survivors. (author)

  13. Study of the effect of temperature, relative humidity and UV radiation on wet-white leather ageing

    OpenAIRE

    Bacardit Dalmases, Anna; Cobos, Mireia; Font Vallès, Joaquim; Jorge Sánchez, Juan; Ollé Otero, Lluís

    2010-01-01

    Since upholstery leather is considered a very high-tech product, a long service life is expected by the costumer. However, this type of leather can undergo extreme environmental conditions that may cause premature ageing. This work deals with the study of the effect of temperature, relative humidity, and UV radiation on leather ageing. Leathers with wet-white tannage were exposed to weathering effects using a climatic chamber in order to identify the most important variables affectin...

  14. A comparison of six different ballast water treatment systems based on UV radiation, electrochlorination and chlorine dioxide

    OpenAIRE

    Stehouwer, P.P.; Buma, A.; Peperzak, L.

    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 follow...

  15. Solar Radiation and the UV index: An application of Numerical Integration, Trigonometric functions, Online Education and the Modelling Process

    OpenAIRE

    Downs, Nathan; Parisi, Alfio V; Galligan, Linda; Turner, Joanna; Amar, Abdurazaq; King, Rachel; Ultra, Filipina; Butler, Harry

    2015-01-01

    A short series of practical classroom mathematics activities employing the use of a large and publicly accessible scientific data set are presented for use by students in years 9 and 10. The activities introduce and build understanding of integral calculus and trigonometric functions through the presentation of practical problem solving that focuses on Public Health and developing a personal understanding of solar ultraviolet radiation and the UV Index. The classroom activities are presented ...

  16. Age-related changes of DNA methylation in cotyledonous leaves of Linum usitatissimum under UV-B radiation

    International Nuclear Information System (INIS)

    The age-related changes of DNA methylation in cotyledonous leaves of Linum usitatissimum subjected to UV-B radiation in the interval 4.23-12.69 kJ/m2 have been studied. The level of methylation is determined by the restriction analysis. Although the study showed no dose-dependence, some methylation spectrum changes in the process of aging of the Linum usitatissimum cotyledonous leaves occurred.

  17. Experimental study of intrinsic losses in iodine lasers pumped by UV radiation from a high-current open discharge

    Energy Technology Data Exchange (ETDEWEB)

    Zuev, V.S.; Korolkov, K.S.; Nosach, O.Yu.; Orlov, E.P.

    1980-12-01

    Results are presented for an experimental study of intrinsic losses in UV-pumped iodine photodissociation lasers. It is found that refraction losses account for most of the intrinsic losses. A refraction loss coefficient of 0.0002 to 0.0006 is measured, as opposed to a loss coefficient of not more than 0.0001 associated with volume absorption of the laser radiation in the active region. Possible means of reducing the intrinsic losses in iodine lasers are considered.

  18. Study of the effect of temperature, relative humidity and UV radiation on chrome-tanned leather ageing

    OpenAIRE

    Bacardit Dalmases, Anna; Jorba, Montse; Font Vallès, Joaquim; Ollé Otero, Lluís

    2012-01-01

    Since leather is strongly affected by three main environmental parameters: temperature, relative humidity and UV radiation, this piece of research focuses on the effect that these three factors have on chrome-tanned leather ageing. Chrome tanned leathers were exposed to weathering effects in a climatic chamber in order to identify the most important variables affecting this weathering process and also to check for any possible interactions. Both a multilevel centralized factorial experimental...

  19. Potential effects of UV radiation on photosynthetic structures of the bloom-forming cyanobacterium Cylindrospermopsis raciborskii CYRF-01

    Directory of Open Access Journals (Sweden)

    Natália Pessoa Noyma

    2015-10-01

    Full Text Available Cyanobacteria are aquatic photosynthetic microorganisms. While of enormous ecological importance, they have also been linked to human and animal illnesses around the world as a consequence of toxin production by some species. Cylindrospermopsis raciborskii, a filamentous nitrogen-fixing cyanobacterium, has attracted considerable attention due to its potential toxicity and ecophysiological adaptability. We investigated whether C. raciborskii could be affected by ultraviolet (UV radiation. Non-axenic cultures of C. raciborskii were exposed to three UV treatments (UVA, UVB or UVA + UVB over a 6 h period, during which cell concentration, viability and ultrastructure were analyzed. UVA and UVA + UVB treatments showed significant negative effects on cell concentration (decreases of 56.4% and 64.3%, respectively. This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe. Over 90% of UVA + UVB- and UVA-treated cells died. UVB did not alter cell concentration, but reduced cell viability in almost 50% of organisms. Transmission electron microscopy (TEM revealed a drastic loss of thylakoids, membranes in which cyanobacteria photosystems are localized, after all treatments. Moreover, other photosynthetic- and metabolic-related structures, such as accessory pigments and polyphosphate granules, were damaged. Quantitative TEM analyses revealed a 95.8 % reduction in cell area occupied by thylakoids after UVA treatment, and reduction of 77.6 % and 81.3 % after UVB and UVA + UVB treatments, respectively. Results demonstrated clear alterations in viability and photosynthetic structures of C. raciborskii induced by various UV radiation fractions. This study facilitates our understanding of the subcellular organization of this cyanobacterium species, identifies specific intracellular targets of UVA and UVB radiation and reinforces the importance of UV radiation as an environmental stressor.

  20. Effects of UV-B radiation on the growth and reproduction of Vicia angustifolia%UV-B辐射对窄叶野豌豆生长繁殖的影响

    Institute of Scientific and Technical Information of China (English)

    王颖; 王兴安; 王仁君; 邱念伟; 马宗琪; 杜国祯

    2012-01-01

    A simulation experiment with supplementation and exclusion of solar ultraviolet-B ( UV-B) radiation was conducted to study the effects of enhanced and near ambient UV-B radiation on the growth and reproduction of alpine annual pasture Vicia angustifolia on Qinghai-Tibet Plateau. Enhanced UV-B decreased the plant height and biomass, biomass allocation to fruit, flower number, and 100-seed mass significantly, delayed flowering stage, increased the concentration degree of flowering and success rate of reproduction, but had little effect on seed yield. Near ambient UV-B radiation made the plant height increased after an initial decrease, decreased biomass allocation to fruit and 100-seed mass, but little affected flowering duration, flower number, and seed yield. Both enhanced and near ambient UV-B radiation could inhibit the growth and production of V. angustifolia, and the effect of enhanced UV-B radiation was even larger.%采用增补和滤除掉部分自然UV-B辐射的模拟试验,研究了增强和近环境UV-B辐射对高寒草甸一年生牧草窄叶野豌豆生长和繁殖的影响.结果表明:增补UV-B辐射处理后,窄叶野豌豆的株高、生物量、分配向果实的生物量、总花数和种子百粒重均显著下降,花期延迟,开花集中度和繁殖成功率有所提高,而种子产量无显著变化.相对于减弱UV-B辐射处理,近环境UV-B辐射使窄叶野豌豆的株高先降后升,分配向果实的生物量减少,花期、花数和种子产量无显著变化,种子百粒重减小.增强和近环境UV-B辐射对窄叶野豌豆的生长和繁殖有一定的抑制作用,且增强UV-B辐射的影响更大.

  1. 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.

  2. The effects of altered levels of UV-B radiation on an Antarctic grass and lichen

    NARCIS (Netherlands)

    Lud, D.; Huiskes, A.H.L.; Moerdijk-Poortvliet, T.C.W.; Rozema, J.J.

    2001-01-01

    We report a long-term experiment on the photosynthetic response of natural vegetation of Deschampsia antarctica (Poaceae) and Turgidosculum complicatulum (Lichenes) to altered UV-B levels on Leonie Island, Antarctica. UV-B above the vegetation was reduced by filter screens during two seasons. Half o

  3. Effect of cadmium ions and ultraviolet (UV-C) radiation on elongation growth of maize coleoptile segments and pH changes in their incubation medium

    International Nuclear Information System (INIS)

    It was found that the treatment of coleoptile segments with cadmium ions as well as with UV-C radiation inhibited both, their elongation growth and acidification of incubation medium. The procedure of cadmium introduction had the substantial influence on inhibition degree of coleoptile segments growth. It was confirmed by the tests of cadmium accumulation in coleoptile segments. The results did not show any additivity of the effects caused by both stress factors (cadmium ions and UV-C radiation). It was also found that the effect of UV-C radiation depended on the level of cadmium in tissue

  4. Induced carotenoid accumulation in Dunaliella salina and Tetraselmis suecica by plant hormones and UV-C radiation.

    Science.gov (United States)

    Ahmed, Faruq; Fanning, Kent; Netzel, Michael; Schenk, Peer M

    2015-11-01

    Carotenoids prevent different degenerative diseases and improve human health. Microalgae are commercially exploited for carotenoids, including astaxanthin and β-carotene. Two commercially important microalgae, Dunaliella salina and Tetraselmis suecica, were treated with plant hormones salicylic acid (SA) and methyl jasmonate (MJ), or by UV-C radiation (T. suecica only) and a combination thereof. Significant increases in total carotenoids were found for D. salina and T. suecica after treatment with MJ (10 μmol/L) and SA (70-250 μmol/L), respectively. T. suecica also had significant increases in total carotenoids following UV-C radiation compared to control cultures. Among the carotenoids, lutein was the highest induced carotenoid. A combination of these two treatments also showed a significant increase in total carotenoids and lutein for T. suecica, when compared to controls. Plant hormones and UV-C radiation may be useful tools for increasing carotenoid accumulation in green microalgae although the responses are species- and dose-specific and should be trialed in medium to large scale to explore commercial production. PMID:26201492

  5. The role of partitioning of reagents in grafting and curing reactions initiated by ionizing radiation and UV

    International Nuclear Information System (INIS)

    Experimental evidence involving monomer absorption studies using tritiated styrene is shown to support the proposal that additives such as mineral acids and certain inorganic salts when dissolved in the monomer solution enhance radiation grafting yields by a mechanism involving partitioning of reagents. Photoinitiators such as benzoin ethyl ether and its methyl analogue are reported as new additives for grafting of styrene in methanol to cellulose and polypropylene initiated by ionizing radiation. The partitioning concept is shown to be relevant in analogous UV grafting and curing processes. (author)

  6. Direct initiation of the photopolymerization of acrylates by 222 nm excimer UV radiation

    International Nuclear Information System (INIS)

    Complete text of publication follows. Usually, the photopolymerisation of functionalised monomers and oligomers requires the addition of one or several photoinitiators to the formulation. The light of typically used mercury lamps (1>250 nm) is mainly absorbed by the photoinitiator leading to initiating species (radicals) with a high quantum yield. The introduction of excimer lamps as monochromatic UV sources with an intense short-wavelength emission opens up new possibilities for a photoinitiator-free initiation of the acrylate polymerisation. Like most other organic compounds, acrylates strongly absorb light with a wavelength shorter than about 220 to 240 nm, and they can therefore be directly excited by the 222 nm excimer radiation from a KrCl* lamp. Real-time FTIR-ATR spectroscopy was used to study the reactivity of various neat acrylates. Depending on the absorption coefficient, aliphatic acrylates can be cured up to a thickness of several microns whereas for highly absorbing aromatic acrylates, the depth of cure reaches only some hundred nanometres. Since the radical yield is low, photopolymerisation without photoinitiator has to be performed in an inert atmosphere. Laser photolysis experiments were carried out with a KrCl* excimer laser (pulse width 20 ns, up to 5 mJ per pulse) to investigate the primary processes of the direct initiation. Additionally, quantum chemical calculations were performed to assist the interpretation of the photolysis data. For all acrylates studied, direct excitation at 222 nm first leads to the formation of a triplet state which is highly localized at the vinyl double bond (and not at the carbonyl group). This triplet state may undergo different reactions like inter- and intramolecular hydrogen transfer and biradical formation as well as the addition to a ground state molecule (chain start). Our current interpretation of the experimental results and the quantum chemical calculations will be presented and discussed

  7. Effect of nutrient supply on photosynthesis and pigmentation to short-term stress (UV radiation) in Gracilaria conferta (Rhodophyta)

    International Nuclear Information System (INIS)

    The effects of increased photosynthetic active radiation (PAR), UV radiation (UVR), and nutrient supply on photosynthetic activity, pigment content, C:N ratio and biomass yield were studied in tank cultivated Gracilaria conferta (Rhodophyta). Electron transport rate (ETR) and biliprotein content were higher under high nutrient supply (HNS), obtained from fishpond effluents, compared to low nutrient supply (LNS), in contrast to mycosporine-like amino acids (MAAs) dynamic. The high MAA content in LNS-algae could be explained by higher UVR penetration in the thallus and by the competition for the use of nutrients with other processes. Effective quantum yield decreased after short-term exposure to high irradiance whereas full recovery in shade was produced only under slightly heat shock. UVA radiation provoked an additional decrease in photosynthesis under high water temperature. UVB radiation reversed UVA's negative effect mainly with HNS. Results support that nutrient-sufficiency help G. conferta to resist environmental changes as short-term temperature increase.

  8. Low-level laser therapy: Effects on human face aged skin and cell viability of HeLa cells exposed to UV radiation

    OpenAIRE

    Mezghani Sana; Hammami Amira; Amri Mohamed

    2015-01-01

    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 radiatio...

  9. Impact of UV-B radiation on photosynthetic assimilation of 14C-bicarbonate and inorganic 15N-compounds by cyanobacteria

    International Nuclear Information System (INIS)

    The cyanobacteria Anabaena cylindrica and Synechococcus leopoliensis (=Anacystis nidulans) were grown at different levels of UV-B radiation (439, 717, 1230 and 1405 J m-2d-1, weighted according Caldwell, 1971) for 2 days. Dry weight was hardly affected but phycocyanin content of both species decreased linearly to the level of UV-B radiation. Contents of protein, carotenoids and chlorophyll a were reduced only after exposure to high doses (1230 J m-2d-1) of UV-B radiation. Photosynthetic 14CO2 fixation of Anabaena cells was reduced linearly with increasing UV-B dose whereas no effect could be observed in Synechococcus. A depression of photosynthetic 15N-nitrate uptake was found after UV-B stress in both species. UV-B irradiance caused an increase of 15N-incorporation into glutamine, but no effect was noted for incorporation into alanine or aspartic acid. An increase of 15N-excess in glutamic acid linear with the UV-B dose was observed in Synechococcus, only. Patterns of 14C-labelled photosynthetic products were either less affected by UV-B radiation (Anabaena) or an enhancement of 14C-label in total amino acids was detected (Synechococcus). The amount of total free amino acids increased parallel to the level of UV-B radiation. Only, the high dose of UV-B (1405 J m-2 d-1, weighted) results in a decrease of the glutamine pool. Our results indicate an inhibition of glutamate synthase by UV-B irradiation in Anabaena, only. Results were discussed with reference to the damage of the photosynthetic apparatus. (orig.)

  10. Effects of solar UV-B radiation on growth, flowering and yield of central and southern European bush bean cultivars (Phaseolus vulgaris L.)

    International Nuclear Information System (INIS)

    Different cultivars of bush beans (Phaseolus vulgaris L.) originating from Central and Southern Europe were grown from July to August/September 1993 up to 7 and 8 weeks, respectively, in two greenhouses covered by different UV-B-absorbing (280-320nm) plastic foils. By using the ambient UV-B radiation of the southern location (Portugal, 38.7°N, 9.1°W) in one of the greenhouses as intense UV-B radiation compared to the reduced radiation in the second greenhouse at the same place, a difference in UV-B of about 8–10% was simulated. All cultivars examined showed significant reductions in height of up to 31,8% in most growth phases under intense UV-B. Also fresh and dry weight as well as leaf area were reduced under intense UV-B in the cultivars Purple Teepee, Cropper Teepee and Goldstrahl, and in early growth phases also in Coco bianco, but with ongoing development this cultivar caught up. Cultivars Hilds Maja, Primel, Manata and Cannellino exhibited no UV-B effects on weight and leaf area. A flowering delay of up to 1 day was observed under intense UV-B in several cultivars. Probably due to this delay the yield (fresh weight of fruits) decreased in all cultivars up to 55% under intense UV-B at harvest time, while the potential yield (sum of buds, opened flowers and fruits) was reduced only in the cultivars Cropper Teepee, Purple Teepee, Cannellino and Goldstrahl. The UV-sensitivity index (UVSI) calculated according to the UV induced changes in growth, dry weight and yield at the second harvest date has shown that all cultivars are UV-sensitive, however the index was numerically higher for Southern European cultivars (average = 2.5) than for Central European ones (average = 2.3) which means that the first group was slightly less UV-sensitive than the second. (author)

  11. [Is UV-A a cause of malignant melanoma?].

    Science.gov (United States)

    Moan, J

    1994-03-20

    The first action spectrum for cutaneous malignant melanoma was published recently (2). This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B-solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagnetic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filters (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. PMID:8191472

  12. Radiation-curable impregnating agents for the conservation of archaeologic wooden objects. Part 2

    International Nuclear Information System (INIS)

    As a continuation of the work described in OEFZS Ber. No. 4165, impregnating agents curable by ionizing radiation, such as free radical polymerizable monomers or artificial resins, have been investigated. Specific weight and viscosity of the liquid mixtures have been as well determined as the specific weight and gel content of the gamma radiation-cured samples. Hardness and elastic behaviour have been estimated only. The shrinkage during hardening was found to be 5 to 12 % for low viscous mixtures (up to 600 mPa.s) and 3 to 8 % for higher viscous impregnating agents. The results are to be discussed. (Author)

  13. UV radiation: sources, effects and risks of human and environmental exposure

    International Nuclear Information System (INIS)

    This paper summarizes the principal results of a review study on UV- -exposure and UV related risks in the Netherlands. Both the present state of affairs and future developments are discussed, the latter partly based on model calculations. The sun is the main UV source to which the whole population is exposed. Solar exposure is estimated to amount at least 90% of the annual UV burden for the Dutch population. For certain groups in the population man made sources are estimated to contribute considerably to the yearly UV dose. Ozone depletion as a result of human activities, growing use of tungsten halogen lamps and increasing application of UV-sources in industry and medicine all tend to increase UV exposure. UV exposure can lead to a wide variety of health effects, among which the induction of skin cancer, skin aging, cataract formation and suppression of immune responses. Risk estimates of these health effects are available for skin cancer and to a lesser extend for cataracts. The estimated UV related skin cancer incidence rate in the Netherlands is 10-3 per year (15 000 cases), and the associated mortality rate amounts to 6-25·10-6 per year (90-400 deaths). The ozone depletion presently observed over the past decade (5% in the Netherlands), is expected to lead to an increased annual mortality rate due to skin cancer of 1,3·10-6 per year. Environmental exposure can influence plant physiology and lead to a decrease of biomass in aquatic as well as terrestrial ecosystems. This may result in adverse effects on the foodweb and biodiversity of ecosystems. Quantitative risk estimates for these effects are very uncertain or lacking. (author)

  14. 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. PMID:26995021

  15. Effect of UV-B Radiation on POD and SOD Isoenzyme of Arabidopsis thaliana%UV-B辐射对拟南芥POD、SOD同工酶的影响

    Institute of Scientific and Technical Information of China (English)

    李晓阳; 孙永星; 宋丽平; 韩榕

    2011-01-01

    选择哥伦比亚生态型(Columbia-0)的野生型拟南芥(Arabidopsis thaliana L.)为供试材料,研究了其POD、SOD同工酶对不同剂量UV-B胁迫的响应.结果显示,POD和SOD同工酶活性与UV-B辐射的剂量关系密切.POD、SOD同工酶活性在低剂量UV-B辐射时呈增加趋势,在中、高剂量UV-B辐射时活性则呈下降趋势.在UV-B胁迫下,POD同工酶酶带没有发生变化;SOD同工酶酶带在胁迫下,出现了新的酶带(SOD4、SOD5).说明拟南芥在受到低剂量的UV-B胁迫下,可以通过提高自身的保护系统来抵御外界不良环境的影响;而受到较高剂量的UV-B胁迫时,会破坏植物的保护系统,造成不可逆的损伤.%Ecotype of Columbia ( Columbia-0) wild-type Arabidopsis (Arabidopsis thaliana L. ) was used to study the respond of UV-B stress of different doses on its POD and SOD isoenzyme. The results showed that, POD and SOD isoenzyme activity was very closed to the dose of UV-B radiation. The activity of POD and SOD isoenzyme showed an increasing trend in the low dose of UV-B radiation, but in the medium and high doses of UV-B radiation, the activity was decreased. In the stress of UV-B, the enzyme belts of POD isozymes did not change, and new belts of SOD isozymes ( SOD4, SODS ) was appeared. It was explained at low doses of UV-B stress, Arabidopsis could improve their own protection system to resist the adverse environmental impact from the outside world, but at high doses of UV-B stress, it would destroy the plant's protection system and cause irreversible damage.

  16. Mouse Models for Efficacy Testing of Agents against Radiation Carcinogenesis — A Literature Review

    Directory of Open Access Journals (Sweden)

    Leena Rivina

    2012-12-01

    Full Text Available As the number of cancer survivors treated with radiation as a part of their therapy regimen is constantly increasing, so is concern about radiation-induced cancers. This increases the need for therapeutic and mitigating agents against secondary neoplasias. Development and efficacy testing of these agents requires not only extensive in vitro assessment, but also a set of reliable animal models of radiation-induced carcinogenesis. The laboratory mouse (Mus musculus remains one of the best animal model systems for cancer research due to its molecular and physiological similarities to man, small size, ease of breeding in captivity and a fully sequenced genome. This work reviews relevant M. musculus inbred and F1 hybrid animal models and methodologies of induction of radiation-induced leukemia, thymic lymphoma, breast, and lung cancer in these models. Where available, the associated molecular pathologies are also included.

  17. UV-B Radiation Suppresses the Growth and Antioxidant Systems of Two Marine Microalgae, Platymonas subcordiformis (Wille) Hazen and Nitzschia closterium (Ehrenb.) W. Sm

    Institute of Scientific and Technical Information of China (English)

    Pei-Yu ZHANG; Juan YU; Xue-Xi TANG

    2005-01-01

    This study investigated whether increased solar UV-B radiation (280-315 nm) could suppress the growth of marine microalgae through effects on their antioxidant systems. Two marine microalgae species, Platymonas subcordiformis (Wille) Hazen and Nitzschia closterium (Ehrenb.) W. Sm, were exposed to a range of UV-B radiation and both showed reductions in their growth rates, and the chlorophyll a (Chl a) and carotenoid (Car) contents when UV-B radiation dose increased. Superoxide anion radical (O2)production and the concentration of hydrogen peroxide (H2O2) and malodiadehyde (MDA) also increased with the increasing of UV-B radiation. Antioxidant systems, non-enzymic components (Car and glutathione content) and enzymic components (superoxide dismutase (SOD) and catalase (CAT) activity), decreased as a result of enhanced UV-B radiation. When the exogenous glutathione (GSH) was added, the effects of UVB radiation on the growth of the two species were alleviated. These results suggest that enhanced UV-B radiation suppressed the antioxidant systems and caused some active oxygen species to accumulate, which in turns retarded the development of the marine microalgae.