WorldWideScience

Sample records for uv light exposure

  1. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...

  2. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...... observation period. Side effects were evaluated clinically. No tumors appeared in untreated control mice or in just IPL-treated mice. Skin tumors developed in UV-exposed mice independently of IPL treatments. The time it took for 50% of the mice to first develop skin tumor ranged from 47 to 49 weeks...... in preoperative UV-exposed mice (p=0.94) and from 22 to 23 weeks in pre- and postoperative UV-exposed mice (p=0.11). IPL rejuvenation of lightly pigmented skin did not induce pigmentary changes (p=1.00). IPL rejuvenation of UV-pigmented skin resulted in an immediate increased skin pigmentation and a subsequent...

  3. Understanding Xeroderma Pigmentosum Complementation Groups Using Gene Expression Profiling after UV-Light Exposure.

    Science.gov (United States)

    Bowden, Nikola A; Beveridge, Natalie J; Ashton, Katie A; Baines, Katherine J; Scott, Rodney J

    2015-07-14

    Children with the recessive genetic disorder Xeroderma Pigmentosum (XP) have extreme sensitivity to UV-light, a 10,000-fold increase in skin cancers from age 2 and rarely live beyond 30 years. There are seven genetic subgroups of XP, which are all resultant of pathogenic mutations in genes in the nucleotide excision repair (NER) pathway and a XP variant resultant of a mutation in translesion synthesis, POLH. The clinical symptoms and severity of the disease is varied across the subgroups, which does not correlate with the functional position of the affected protein in the NER pathway. The aim of this study was to further understand the biology of XP subgroups, particularly those that manifest with neurological symptoms. Whole genome gene expression profiling of fibroblasts from each XP complementation group was assessed before and after UV-light exposure. The biological pathways with altered gene expression after UV-light exposure were distinct for each subtype and contained oncogenic related functions such as perturbation of cell cycle, apoptosis, proliferation and differentiation. Patients from the subgroups XP-B and XP-F were the only subgroups to have transcripts associated with neuronal activity altered after UV-light exposure. This study will assist in furthering our understanding of the different subtypes of XP which will lead to better diagnosis, treatment and management of the disease.

  4. Non-melanoma skin cancer: occupational risk from UV light and arsenic exposure.

    Science.gov (United States)

    Surdu, Simona

    2014-01-01

    Non-melanoma skin cancer (NMSC) has a significant impact on public health and health care costs as a result of high morbidity and disfigurement due to the destruction of surrounding tissues. Although the mortality rates of these tumors are low, the high incidence rates determine a considerable number of deaths. NMSC is the most common type of skin cancer, representing about 1/3 of all malignancies diagnosed worldwide each year. The most common NMSC are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Studies on humans and experimental animals indicate that ultraviolet (UV) light and arsenic play important roles in the development of these skin malignancies. Several epidemiological studies have investigated the risk of developing NMSC and the potential link between exposure to sunlight and arsenic in the agricultural and industrial occupational settings. To date, the published literature suggests that there is no apparent skin cancer risk as regards workplace exposure to artificial UV light or arsenic. Concerning UV light from sun exposure at the workplace, most published studies indicated an elevated risk for SCC, but are less conclusive for BCC. Many of these studies are limited by the methodology used in the evaluation of occupational exposure and the lack of adjustment for major confounders. Therefore, further epidemiological studies are required to focus on exposure assessment at the individual level as well as potential interactions with other occupational and non-occupational exposures and individual susceptibility. In doing so, we can better quantify the true risk of skin cancer in exposed workers and inform effective public health prevention programs.

  5. Bactericidal effectiveness of modulated UV light

    International Nuclear Information System (INIS)

    Bank, H.L.; John, J.; Schmehl, M.K.; Dratch, R.J.

    1990-01-01

    Studies were designed to evaluate the effectiveness of pulsed modulated UV light waveforms for killing bacteria. Exposure of five strains of bacteria to the modulated information encoded in the light decreased the colony population from a confluent lawn to less than 20 colonies. However, approximately 2,000 colonies survived treatment with the same intensity and time of exposure to UV light lacking the modulated information

  6. UV-light exposure of insulin: pharmaceutical implications upon covalent insulin dityrosine dimerization and disulphide bond photolysis.

    Science.gov (United States)

    Correia, Manuel; Neves-Petersen, Maria Teresa; Jeppesen, Per Bendix; Gregersen, Søren; Petersen, Steffen B

    2012-01-01

    In this work we report the effects of continuous UV-light (276 nm, ~2.20 W.m(-2)) excitation of human insulin on its absorption and fluorescence properties, structure and functionality. Continuous UV-excitation of the peptide hormone in solution leads to the progressive formation of tyrosine photo-product dityrosine, formed upon tyrosine radical cross-linkage. Absorbance, fluorescence emission and excitation data confirm dityrosine formation, leading to covalent insulin dimerization. Furthermore, UV-excitation of insulin induces disulphide bridge breakage. Near- and far-UV-CD spectroscopy shows that UV-excitation of insulin induces secondary and tertiary structure losses. In native insulin, the A and B chains are held together by two disulphide bridges. Disruption of either of these bonds is likely to affect insulin's structure. The UV-light induced structural changes impair its antibody binding capability and in vitro hormonal function. After 1.5 and 3.5 h of 276 nm excitation there is a 33.7% and 62.1% decrease in concentration of insulin recognized by guinea pig anti-insulin antibodies, respectively. Glucose uptake by human skeletal muscle cells decreases 61.7% when the cells are incubated with pre UV-illuminated insulin during 1.5 h. The observations presented in this work highlight the importance of protecting insulin and other drugs from UV-light exposure, which is of outmost relevance to the pharmaceutical industry. Several drug formulations containing insulin in hexameric, dimeric and monomeric forms can be exposed to natural and artificial UV-light during their production, packaging, storage or administration phases. We can estimate that direct long-term exposure of insulin to sunlight and common light sources for indoors lighting and UV-sterilization in industries can be sufficient to induce irreversible changes to human insulin structure. Routine fluorescence and absorption measurements in laboratory experiments may also induce changes in protein

  7. UV-light exposure of insulin: pharmaceutical implications upon covalent insulin dityrosine dimerization and disulphide bond photolysis.

    Directory of Open Access Journals (Sweden)

    Manuel Correia

    Full Text Available In this work we report the effects of continuous UV-light (276 nm, ~2.20 W.m(-2 excitation of human insulin on its absorption and fluorescence properties, structure and functionality. Continuous UV-excitation of the peptide hormone in solution leads to the progressive formation of tyrosine photo-product dityrosine, formed upon tyrosine radical cross-linkage. Absorbance, fluorescence emission and excitation data confirm dityrosine formation, leading to covalent insulin dimerization. Furthermore, UV-excitation of insulin induces disulphide bridge breakage. Near- and far-UV-CD spectroscopy shows that UV-excitation of insulin induces secondary and tertiary structure losses. In native insulin, the A and B chains are held together by two disulphide bridges. Disruption of either of these bonds is likely to affect insulin's structure. The UV-light induced structural changes impair its antibody binding capability and in vitro hormonal function. After 1.5 and 3.5 h of 276 nm excitation there is a 33.7% and 62.1% decrease in concentration of insulin recognized by guinea pig anti-insulin antibodies, respectively. Glucose uptake by human skeletal muscle cells decreases 61.7% when the cells are incubated with pre UV-illuminated insulin during 1.5 h. The observations presented in this work highlight the importance of protecting insulin and other drugs from UV-light exposure, which is of outmost relevance to the pharmaceutical industry. Several drug formulations containing insulin in hexameric, dimeric and monomeric forms can be exposed to natural and artificial UV-light during their production, packaging, storage or administration phases. We can estimate that direct long-term exposure of insulin to sunlight and common light sources for indoors lighting and UV-sterilization in industries can be sufficient to induce irreversible changes to human insulin structure. Routine fluorescence and absorption measurements in laboratory experiments may also induce changes

  8. UV exposure in cars.

    Science.gov (United States)

    Moehrle, Matthias; Soballa, Martin; Korn, Manfred

    2003-08-01

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  10. Cu-doped TiO2 nanoparticles enhance survival of Shewanella oneidensis MR-1 under Ultraviolet Light (UV) exposure

    International Nuclear Information System (INIS)

    Wu, Bing; Zhuang, Wei-Qin; Sahu, Manoranjan; Biswas, Pratim; Tang, Yinjie J.

    2011-01-01

    It has been shown that photocatalytic TiO 2 nanoparticles (NPs) can be used as an efficient anti-microbial agent under UV light due to generation of reactive oxygen species (ROS), while Shewanella oneidensis MR-1 is a metal-reducing bacterium highly susceptible to UV radiation. Interestingly, we found that the presence of Cu-doped TiO 2 NPs in the cultural medium dramatically increased the survival rates (based on colony-forming unit) of strain MR-1 by over 10,000-fold (incubation without shaking) and ∼ 200 fold (incubation with shaking) after a 2-h exposure to UV light. Gene expression results (via qPCR measurement) indicated that the DNA repair gene recA in MR-1 was significantly induced by UV exposure (indicating cellular damage under UV stress), but the influence of NPs on recA expression was not statistically evident. Plausible explanations to NP attenuation of UV stresses are: 1. TiO 2 based NPs are capable of scattering and absorbing UV light and thus create a shading effect to protect MR-1 from UV radiation; 2. more importantly, Cu-doped TiO 2 NPs can co-agglomerate with MR-1 to form large flocs that improves cells' survival against the environmental stresses. This study improves our understanding of NP ecological impacts under natural solar radiation and provides useful insights to application of photocatalytic-NPs for bacterial disinfection.

  11. An investigation into UV light exposure as an experimental model for artificial aging on tensile strength and force delivery of elastomeric chain.

    Science.gov (United States)

    Wahab, Siti Waznah; Bister, Dirk; Sherriff, Martyn

    2014-02-01

    This study investigated the effect of ultraviolet type A light (UVA) exposure on the tensile properties of elastomeric chain. UVA light exposure was used as model for artificial aging, simulating prolonged storage of elastomeric chain. Tensile strength (n = 60) was measured after exposing Ormco, Forestadent and 3M chains to UVA light for 0, 2, 3, and 4 weeks. Force decay was measured (n = 60) using chain exposed for 5, 10, and 14 days. The chains were subsequently stretched at a constant distance and the resulting forces measured at 0, 1, 24 hours and 7, 14, 21, and 28 days. This test simulated a clinical scenario of pre-stretching and subsequent shortening of elastomeric chain. Tensile strength had statistically significant difference and was directly related to the duration of ultraviolet (UV) light exposure. Forestadent chain, which had the second highest value for the 'as received' product, showed the most consistent values over time with the lowest degradation. Ormco showed the lowest values for 'as received' as well as after UV exposure; 3M chain had the highest loss of tensile strength. Force decay was also significantly different. UV light exposure of 10 days or more appears to mark a 'watershed' between products: 3M had most survivors, Forestadent chain had some survivors, depending on the time the chain was stretched for. None of the Ormco product survived UV light exposure for more than 5 days. UVA light exposure may be used as a model for artificial aging as it reduces force delivery and tensile strength of exposed chains.

  12. AlN ceramics as a detector for UV exposure

    International Nuclear Information System (INIS)

    Trinkler, L.; Berzina, B.; Boetter-Jensen, L.; Christensen, P.; Palcevskis, E.

    1999-01-01

    AlN-Y 2 O 3 ceramics is proposed for application in the field of UV detection and dosimetry. Both thermoluminescence (TL) and optically stimulated luminescence (OSL) signals from the material have been studied after exposure to UV light. AlN-Y 2 O 3 ceramics demonstrates very high sensitivity to UV light over a broad spectral region. The TL is characterized by a linear dose dependence over a large range. The fading rate of the UV-induced TL and OSL signals on storage at room temperature is lower than in the case of exposure to ionizing irradiation. (au)

  13. Investigation of uniformity field generated from freeform lens with UV LED exposure system

    Science.gov (United States)

    Ciou, F. Y.; Chen, Y. C.; Pan, C. T.; Lin, P. H.; Lin, P. H.; Hsu, F. T.

    2015-03-01

    In the exposure process, the intensity and uniformity of light in the exposure area directly influenced the precision of products. UV-LED (Ultraviolet Light-Emitting Diode) exposure system was established to reduce the radiation leakage and increase the energy efficiency for energy saving. It is a trend that conventional mercury lamp could be replaced with UV-LED exposure system. This study was based on the law of conservation of energy and law of refraction of optical field distributing on the target plane. With these, a freeform lens with uniform light field of main exposure area could be designed. The light outside the exposure area could be concentrated into the area to improve the intensity of light. The refraction index and UV transmittance of Polydimethylsiloxane (PDMS) is 1.43 at 385 nm wavelength and 85-90%, respectively. The PDMS was used to fabricate the optics lens for UV-LEDs. The average illumination and the uniformity could be obtained by increasing the number of UV-LEDs and the spacing of different arrangement modes. After exposure process with PDMS lens, about 5% inaccuracy was obtained. Comparing to 10% inaccuracy of general exposure system, it shows that it is available to replace conventional exposure lamp with using UV-LEDs.

  14. Physiological limit of the daily endogenous cholecalciferol synthesis from UV light in cattle.

    Science.gov (United States)

    Hymøller, L; Jensen, S K; Kaas, P; Jakobsen, J

    2017-04-01

    The link between UV light (sunlight) and endogenous cholecalciferol (vitamin D 3 ) synthesis in the skin of humans has been known for more than a 100 years, since doctors for the first time successfully used UV light to cure rickets in children. Years later, it was shown that UV light also had a significant effect on the cholecalciferol status in the body of cattle. The cholecalciferol status in the body is measured as the plasma concentration of 25-hydroxycholecalciferol, which in cattle and humans is the major circulating metabolite of cholecalciferol. Very little is, however, known about the quantitative efficiency of UV light as a source of cholecalciferol in cattle nutrition and physiology. Hence, the aim of this study was to determine the efficiency of using UV light for increasing the plasma 25-hydroxycholecalciferol concentration in cholecalciferol-deprived cattle. Twelve cows deprived of cholecalciferol for 6 months were divided into three treatment groups and exposed to UV light for 30, 90 or 120 min/day during 28 days. UV-light wavelengths ranged from 280 to 415 nm and 30-min exposure to the UV light was equivalent to 60-min average summer-sunlight exposure at 56 °N. Blood samples were collected every 3-4 days and analysed for 25-hydroxycholecalciferol and cholecalciferol. Results showed that increasing the exposure time from 90-120 min/day did not change the slope of the daily increase in plasma 25-hydroxycholecalciferol. Hence, it appears that cholecalciferol-deprived dairy cattle are able to increase their plasma 25-hydroxycholecalciferol concentration by a maximum of 1 ng/ml/day from UV-light exposure. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  15. Skin β-Endorphin Mediates Addiction to UV Light

    OpenAIRE

    Fell, Gillian L.; Robinson, Kathleen C.; Mao, Jianren; Woolf, Clifford J.; Fisher, David E.

    2014-01-01

    Ultraviolet light is an established carcinogen yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize Proopiomelanocortin that is processed to Melanocyte Stimulating Hormone, inducing tanning. We show that in rodents another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed, and reversed by pharmacologic op...

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

  19. Skin β-endorphin mediates addiction to UV light.

    Science.gov (United States)

    Fell, Gillian L; Robinson, Kathleen C; Mao, Jianren; Woolf, Clifford J; Fisher, David E

    2014-06-19

    UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize proopiomelanocortin (POMC) that is processed to melanocyte-stimulating hormone, inducing tanning. We show that, in rodents, another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed and reversed by pharmacologic opioid antagonism. Opioid blockade also elicits withdrawal signs after chronic UV exposure. This effect was sufficient to guide operant behavioral choices to avoidance of opioid withdrawal (conditioned place aversion). These UV-induced nociceptive and behavioral effects were absent in β-endorphin knockout mice and in mice lacking p53-mediated POMC induction in epidermal keratinocytes. Although primordial UV addiction, mediated by the hedonic action of β-endorphin and anhedonic effects of withdrawal, may theoretically have enhanced evolutionary vitamin D biosynthesis, it now may contribute to the relentless rise in skin cancer incidence in humans. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Ocular exposure to ultraviolet and visible radiation from light sources

    International Nuclear Information System (INIS)

    Hietanen, M.

    1992-01-01

    Exposure of the eyes to UV radiation and blue light of artificial light sources and the sun was evaluated. A spectroradiometer was used to determine the spectral irradiance at 1 nm intervals from 250 to 800 nm. Various groups of workers are at risk of ocular over-exposure to optical radiation, outdoor workers maintenance personnel of bright light source as and wear eye-protectors with effective filtering of UV radiation and blue light. (author)

  1. Response of human epidermal keratinocytes to UV light

    International Nuclear Information System (INIS)

    Kartasova, A.A.

    1987-01-01

    This thesis presents a study on the response of human epidermal keratinocytes to UV light as well as to other agents like 4-NQO and TPA. The effects of ultraviolet (UV) light on the protein synthesis in cultured keratinocytes are presented in ch. III. The next chapter describes the construction of a cDNA library using mRNA isolated from UV irradiated kernatinocytes. This library was differentially screened with cDNA probes synthesized on mRNA from either UV irradiated or nonirradiated cells. Several groups of cDNA clones corresponding to transcripts whose level in the cytoplasm seem to be affected by exposure to UV light have been isolated and characterized by cross-hybridization, sequencing and Northern blot analysis. More detailed analysis of some of the cDNA clones is presented in the two chapters following ch. IV. The complete cDNA sequence of the proteinase inhibitor cystatin A and the modulation of its expression by UV light and the carcinogen 4-nitroquinoline 1-oxide (4-NQO) in keratinocytes are described in ch. V. Two other groups of cDNA clones have been isolated which do not cross-hybridize with each other on Southern blots. However, the primary structures of the proteins deduced from the nucleotide sequences of these two groups of cDNA clones are very similar. 212 refs.; 33 figs.; 2 tabs

  2. The UV and Laser Aging for PMMA/BDK/Azo-dye Polymer Blend Cured by UV Light Beams

    International Nuclear Information System (INIS)

    Ahmad, A A; Omari, A M

    2015-01-01

    A polymeric-based solution blend composed of Azo-dye methyl red (MR) doped with polymethelmethacrelate (PMMA) solution, in addition, to the BenzylDimethylKetal (BDK) photoinitiator was made with optimum molar ratios and deposited on glass substrate by spin coating technique. The samples were then exposed to UV light beams in order to assist the layers polymerization by the proper exposure process. The photo chemical reaction occurred during the UV light polymerization process induces photo refractive changes which were presented as a function of wavelength or photon energy. Two main strong absorption peaks were observed in the films at around 330 nm (3.75 eV) and 500 nm (2.48 eV) for different curing time periods. This phenomenon enhances the films usage for optical data storage media at these two wavelengths. Since the deposited films were then useful as based layers for Read/Write optical data storage media, they were then tested by UV or laser Read/Write beams independently. The optical properties of the films were investigated while exposed to each beam. Finally, their optical properties were investigated as a function of aging time in order to relate the temporary and/or permanent light-exposure effect on the films compared to their optical properties before the light exposure. The films show a low absorbance at 630 nm (1.97 eV) and high absorbance at 480 nm (2.58 eV). This fact makes it possible to record holographic gratings in the polymeric film upon light exposure. In all cases the optical properties were evaluated by using the very sensitive, non destructive surface testing spectroscopic ellipsometry technique. The films were characterized in the spectral range of 300 to 1000 nm using Lorentz oscillator model with one oscillator centred at 4.15 eV. This study has been supported by the SEM and EDAX results to investigate the effect of the UV and visible beams on their optical properties. The results of this research determined the proper conditions for

  3. Computer numerical control (CNC) lithography: light-motion synchronized UV-LED lithography for 3D microfabrication

    International Nuclear Information System (INIS)

    Kim, Jungkwun; Allen, Mark G; Yoon, Yong-Kyu

    2016-01-01

    This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array. (paper)

  4. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K; Leszczynski, K; Visuri, R; Ylianttila, L [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1996-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  5. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  6. Solar UV light regulates flavonoid metabolism in apple (Malus x domestica).

    Science.gov (United States)

    Henry-Kirk, Rebecca A; Plunkett, Blue; Hall, Miriam; McGhie, Tony; Allan, Andrew C; Wargent, Jason J; Espley, Richard V

    2018-03-01

    Ultraviolet-B light (UV-B) is one environmental signal perceived by plants that affects the flavonoid pathway and influences the levels of anthocyanins, flavonols, and proanthocyanidins. To understand the mechanisms underlying UV exposure, apple trees were grown under spectral filters that altered transmission of solar UV light. Fruit analysis showed that UV induced changes in physiology, metabolism, and gene expression levels during development over a season. These changes were sustained after storage. Under low UV, ripening was delayed, fruit size decreased, and anthocyanin and flavonols were reduced. Expression analysis showed changes in response to UV light levels for genes in the regulation and biosynthesis of anthocyanin and flavonols. Transcription of flavonol synthase (FLS), ELONGATED HYPOCOTYL 5 (HY5), MYB10, and MYB22 were down-regulated throughout fruit development under reduced UV. Functional testing showed that the FLS promoter was activated by HY5, and this response was enhanced by the presence of MYB22. The MYB22 promoter can also be activated by the anthocyanin regulator, MYB10. As ambient levels of UV light vary around the globe, this study has implications for future crop production, the quality of which can be determined by the response to UV. © 2018 John Wiley & Sons Ltd.

  7. UV light and urban pollution: bad cocktail for mosquitoes?

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ralf eMüller-Xing

    2014-09-01

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

  9. Regulation of the expression of NADP-malic enzyme by UV-B, red and far-red light in maize seedlings

    Directory of Open Access Journals (Sweden)

    P. Casati

    1999-10-01

    Full Text Available The induction of nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME in etiolated maize (Zea mays seedlings by UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400-700 nm was investigated by measuring changes in activity, protein quantity and RNA levels as a function of intensity and duration of exposure to the different radiations. Under low levels of PAR, exposure to UV-B radiation but not UV-A radiation for 6 to 24 h caused a marked increase in the enzyme levels similar to that observed under high PAR in the absence of UV-B. UV-B treatment of green leaves following a 12-h dark period also caused an increase in NADP-ME expression. Exposure to UV-B radiation for only 5 min resulted in a rapid increase of the enzyme, followed by a more gradual rise with longer exposure up to 6 h. Low levels of red light for 5 min or 6 h were also effective in inducing NADP-ME activity equivalent to that obtained with UV-B radiation. A 5-min exposure to far-red light following UV-B or red light treatment reversed the induction of NADP-ME, and this effect could be eliminated by further treatment with UV-B or red light. These results indicate that physiological levels of UV-B radiation can have a positive effect on the induction of this photosynthetic enzyme. The reducing power and pyruvate generated by the activity of NADP-ME may be used for respiration, in cellular repair processes and as substrates for fatty acid synthesis required for membrane repair.

  10. [ASSOCIATION OF SKIN PHOTOTYPE AND UV EXPOSURE WITH EXPRESSION OF

    Science.gov (United States)

    Drvar, D Ledić; Lipozenčić, J; Mokos, Z Bukvić; Ilić, I; Knežević, F

    2015-01-01

    An increase in the incidence of cancer, in particular skin cancer, has been observed in the last few decades. Skin cancer represents a significant public health problem in Croatia and worldwide. Cutaneous squamous cell carcinoma (cSCC) is a malignant tumor arising in epidermal keratinocytes. Together with basal cell carcinoma it belongs to non-melanoma skin cancers, which are the most common cancers in humans. The lifetime risk of cSCC development in Caucasian population is nowadays estimated to about 15%, which makes it double compared to 20 years ago. The most probable causes are increased ultraviolet light (UV) exposure (exposure to artificial UV sources in suntan parlors, spending more time outdoors, changes in fashion, as well as ozone holes), and longer life expectancy. In its etiopathogenesis, important risk factors include genetic factors, fair-skin phototype, UV exposure, chronic degenerative and inflammatory conditions, chemical factors, oncogenic viruses, immunosuppression, ionizing radiation, as well as habitual risk factors. Human epidermal growth factor receptor (HER) family is involved in the control of multiple signal pathways. Their dysregulation is associated with development of many cancers such as breast carcinoma, non-small cell lung carcinoma, ovarian carcinoma, carcinoma of pancreas, head and neck carcinoma, as well as glioblastoma. The objective of our investigation was to establish if there is association of the skin phototype and UV exposure with the expression of HER receptors, Ki67 and p53 in patients with cSCC. Study group included 101 cSCC patients. Inclusion criteria were age >50, both sexes, histopathologically confirmed cSCC, no previous therapy, specimens sufficient for immunohistochemistry, and complete clinical data collected by a questionnaire. Material obtained by excisional biopsy was completely histopathologically evaluated and additional tissue slices were immunohistochemically analyzed. Statistical analysis of the sample

  11. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  12. Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure

    DEFF Research Database (Denmark)

    Edberg, Jesper; Iandolo, Donata; Brooke, Robert

    2016-01-01

    to control the conductivity in the conjugated polymer poly(3,4-ethylenedioxythiophene):tosylate by more than six orders of magnitude in addition to producing high-resolution patterns and optical gradients. The mechanism behind the modulation in the polymerization kinetics by UV light irradiation as well...

  13. UV light induced DNA damages and the radiation protection effects of Lingzi mushroom extract

    International Nuclear Information System (INIS)

    Vo Thi Thuong Lan; Dinh Ba Tuan; Ta Bich Thuan; Tran Bang Diep; Tran Minh Quynh

    2016-01-01

    UV light has strongly influenced on the growth of E. coli as well as caused DNA damages. Configurations of both genomic DNA and pUC 19 plasmids extracted from E. coli were significantly changed by the exposure to UV light of 254 nm and DLT, an extract of Ganoderma lucidum Lingzi mushroom. The results also revealed the radio-protective effects of DLT to UV radiation. By adding 2% DLT to its culturing suspension, the growth of E. coli was significantly decreased, whereas a low DLT amount of about 0.5% slightly improved its growth, indicated that the DLT extract can be used as a promising protective substance against UV radiation. At the molecular level, the radio-protective effects of DLT were observed for both UV treated DNA and protein. Thus, DLT can protect DNA in vivo, but not in vitro. This effect was also observed for Taq polymerase, suggested that the radioprotection effect of DLT may due to it accelerated the degradation of radicals or species that produced in the suspensions during UV exposure. (author)

  14. Dermal damage promoted by repeated low-level UV-A1 exposure despite tanning response in human skin.

    Science.gov (United States)

    Wang, Frank; Smith, Noah R; Tran, Bao Anh Patrick; Kang, Sewon; Voorhees, John J; Fisher, Gary J

    2014-04-01

    Solar UV irradiation causes photoaging, characterized by fragmentation and reduced production of type I collagen fibrils that provide strength to skin. Exposure to UV-B irradiation (280-320 nm) causes these changes by inducing matrix metalloproteinase 1 and suppressing type I collagen synthesis. The role of UV-A irradiation (320-400 nm) in promoting similar molecular alterations is less clear yet important to consider because it is 10 to 100 times more abundant in natural sunlight than UV-B irradiation and penetrates deeper into the dermis than UV-B irradiation. Most (approximately 75%) of solar UV-A irradiation is composed of UV-A1 irradiation (340-400 nm), which is also the primary component of tanning beds. To evaluate the effects of low levels of UV-A1 irradiation, as might be encountered in daily life, on expression of matrix metalloproteinase 1 and type I procollagen (the precursor of type I collagen). In vivo biochemical analyses were conducted after UV-A1 irradiation of normal human skin at an academic referral center. Participants included 22 healthy individuals without skin disease. Skin pigmentation was measured by a color meter (chromometer) under the L* variable (luminescence), which ranges from 0 (black) to 100 (white). Gene expression in skin samples was assessed by real-time polymerase chain reaction. Lightly pigmented human skin (L* >65) was exposed up to 4 times (1 exposure/d) to UV-A1 irradiation at a low dose (20 J/cm2), mimicking UV-A levels from strong sun exposure lasting approximately 2 hours. A single exposure to low-dose UV-A1 irradiation darkened skin slightly and did not alter matrix metalloproteinase 1 or type I procollagen gene expression. With repeated low-dose UV-A1 irradiation, skin darkened incrementally with each exposure. Despite this darkening, 2 or more exposures to low-dose UV-A1 irradiation significantly induced matrix metalloproteinase 1 gene expression, which increased progressively with successive exposures. Repeated UV-A1

  15. Sunscreens with broad-spectrum absorption decrease the trans TO cis photoisomerization of urocanic acid in the human stratum corneum after multiple UV light exposures

    International Nuclear Information System (INIS)

    Krien, P.M.; Moyal, D.

    1994-01-01

    The trans to cis photoisomerization of urocanic acid (UCA) in skin is considered to play an important role in the mechanism of immunosuppression. We have investigated the effects of skin type and various sunscreens with low sun protection factor (SPF) on the UV-induced cis-UCA formation in human skin after exposure to artificial UV light. The rate of cis-UCA formation depends little on the skin type and is reduced by topical application of sunscreens. The rate of cis-UCA formation decreases with increasing SPF and only broad-spectrum, highly protective sunscreens offer protection against the UV-induced formation of cis-UCA, which accumulates in the stratum corneum after multiple UV exposures. A theoretical approach to estimate the distribution of cis-UCA after irradiation indicates that this compound may diffuse into the deeper layers of the epidermis with D ∼ 10 -17 m 2 /s, and that its elimination from the stratum corneum is mainly due to desquamation. (author)

  16. Ultraviolet radiation exposure from UV-transilluminators.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Jahangir-Blourchian, Mahdi

    2005-10-01

    UV-transilluminators use ultraviolet radiation (UVR) to visualize proteins, DNA, RNA, and their precursors in a gel electrophoresis procedure. This study was initiated to evaluate workers' exposure to UVR during their use of UV-transilluminators. The levels of irradiance of UV-A, UV-B, and UV-C were determined for 29 UV-transilluminators at arbitrary measuring locations of 6, 25, 62, and 125 cm from the center of the UV-transilluminator's filter surface in the direction of the operator's head. The operators (faculty, research staff, and graduate students) worked within 62 cm of the transilluminators, with most subjects commonly working at time ranged from 1 to 60 min. Actinic hazard (effective irradiance level of UVR) was also determined for three representative UV-transilluminators at arbitrary measuring locations of 2.5, 5, 10, 15, 20, 30, 40, and 50 cm from these sets' filter surface in the direction of the operator's head. The allowable exposure time for these instruments was less than 20 sec within 15 cm, less than 35 sec within 25 cm, and less than 2 min within 50 cm from the UV-transilluminators' filter surface. The results of this study suggest that the use of UV-transilluminators exposes operators to levels of UVR in excess of exposure guidelines. It is recommended that special safety training be provided for the affected employees and that exposure should be controlled by one or the combination of automation, substitution, isolation, posted warning signs, shielding, and/or personal protective equipment.

  17. [Light protection: principles of UV protection].

    Science.gov (United States)

    Stege, H; Mang, R

    2006-05-01

    UV radiation is responsible for the induction of epithelial and melanocytic skin cancer, photoaging, and photodermatoses. UV protection is necessary to prevent damage caused by non-physiologic exposure. UV protection includes not only reduction of sun exposure but also use of sun protective filters, UV protective clothes, DNA repair enzymes, and antioxidant supplementation. Consumers are uncertain about the possibilities and limitations of commercial sun protection measures. Dermatologists must explain protective measures to the general public which continues to believe that UV-tanned skin is healthy. The sunscreen market is a highly competitive but lucrative market. The range of products with different designations and promises makes difficult for both consumers and dermatologists to determine what is sensible UV protection.

  18. Modifications of γ-ray sensitivity of bacterial membranes by pre-exposure to light

    International Nuclear Information System (INIS)

    Misiti-Dorello, P.; Cancelliere, G.; De Martino, G.; Quintilini, M.

    1976-01-01

    The exposure of E. coli B/r cells to ultraviolet or to visible light prior to irradiation with γ-rays modifies the sensitivity of the cell membrane to radiation damage responsible for the intracellular K + content. Exposure of bacterial cells to sublethal doses of UV radiation increases their sensitivity to γ-induced membrane damage, while exposure to visible light has the opposite effect. In combined exposures, the visible light, either given before or after the UV always produces a strong photoprotective effect. In either case, the photosensitizing effect of UV is completely suppressed. The photoprotection decays with time if cell suspensions are left in the dark before γ-irradiation. At O 0 C, the half-life of the photoprotective effect is 25 min at pH 7 and 100 min at pH 7.5. The decay is due to the presence of oxygen. The light band responsible for the induction of photoprotection has been estimated to lie in the wavelenght region between 540 and 580 nm. (orig./MG) [de

  19. 207-nm UV Light-A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. II: In-Vivo Safety Studies.

    Science.gov (United States)

    Buonanno, Manuela; Stanislauskas, Milda; Ponnaiya, Brian; Bigelow, Alan W; Randers-Pehrson, Gerhard; Xu, Yanping; Shuryak, Igor; Smilenov, Lubomir; Owens, David M; Brenner, David J

    2016-01-01

    UVC light generated by conventional germicidal lamps is a well-established anti-microbial modality, effective against both bacteria and viruses. However, it is a human health hazard, being both carcinogenic and cataractogenic. Earlier studies showed that single-wavelength far-UVC light (207 nm) generated by excimer lamps kills bacteria without apparent harm to human skin tissue in vitro. The biophysical explanation is that, due to its extremely short range in biological material, 207 nm UV light cannot penetrate the human stratum corneum (the outer dead-cell skin layer, thickness 5-20 μm) nor even the cytoplasm of individual human cells. By contrast, 207 nm UV light can penetrate bacteria and viruses because these cells are physically much smaller. To test the biophysically-based hypothesis that 207 nm UV light is not cytotoxic to exposed mammalian skin in vivo. Hairless mice were exposed to a bactericidal UV fluence of 157 mJ/cm2 delivered by a filtered Kr-Br excimer lamp producing monoenergetic 207-nm UV light, or delivered by a conventional 254-nm UV germicidal lamp. Sham irradiations constituted the negative control. Eight relevant cellular and molecular damage endpoints including epidermal hyperplasia, pre-mutagenic UV-associated DNA lesions, skin inflammation, and normal cell proliferation and differentiation were evaluated in mice dorsal skin harvested 48 h after UV exposure. While conventional germicidal UV (254 nm) exposure produced significant effects for all the studied skin damage endpoints, the same fluence of 207 nm UV light produced results that were not statistically distinguishable from the zero exposure controls. As predicted by biophysical considerations and in agreement with earlier in vitro studies, 207-nm light does not appear to be significantly cytotoxic to mouse skin. These results suggest that excimer-based far-UVC light could potentially be used for its anti-microbial properties, but without the associated hazards to skin of conventional

  20. Identification of antimycotic drugs transformation products upon UV exposure

    Energy Technology Data Exchange (ETDEWEB)

    Casado, Jorge; Rodríguez, Isaac, E-mail: isaac.rodriguez@usc.es; Ramil, María; Cela, Rafael

    2015-05-30

    Highlights: • Evaluation of antimycotic drugs UV stabilities in model supports. • Simultaneous detection of precursor drugs and transformation products. • Transformation products identification from their scan, accurate MS/MS spectra. • Directed search of identified transformation products in sand and soil samples. • Preliminary toxicity estimations. - Abstract: The reactivity of three imidazolic, environmental persistent antimycotic drugs (clotrimazole, CTZ; ketoconazole, KTZ; and miconazole, MCZ) upon exposure to ultraviolet (UV) radiation is discussed. First, precursor compounds were immobilized in a silicone support which was further exposed to UV light at two different wavelengths: 254 and 365 nm. After solvent desorption, degradation kinetics of the precursor pharmaceuticals, identification of the arising transformation products (TPs) and evaluation of their time-course were investigated by liquid chromatography (LC) with quadrupole time-of-flight (QTOF) mass spectrometry (MS) detection. The three antimycotics displayed similar stabilities when exposed to 254 nm light; however, CTZ was significantly more stable than MCZ and KTZ when irradiated with the 365 nm lamp. TPs identified in silicone supports resulted from de-chlorination, cleavage, intra-molecular cyclization and hydroxylation reactions. Many of these species were also detected when exposing other solid matrices, such as sand and agricultural soil, previously spiked with target compounds, to UV light. The 50% estimated lethal concentration, calculated using the 48-h Daphnia magna test, for the two main TPs of CTZ and MCZ, at both wavelengths, were lower than those corresponding to the precursor drugs.

  1. Identification of antimycotic drugs transformation products upon UV exposure

    International Nuclear Information System (INIS)

    Casado, Jorge; Rodríguez, Isaac; Ramil, María; Cela, Rafael

    2015-01-01

    Highlights: • Evaluation of antimycotic drugs UV stabilities in model supports. • Simultaneous detection of precursor drugs and transformation products. • Transformation products identification from their scan, accurate MS/MS spectra. • Directed search of identified transformation products in sand and soil samples. • Preliminary toxicity estimations. - Abstract: The reactivity of three imidazolic, environmental persistent antimycotic drugs (clotrimazole, CTZ; ketoconazole, KTZ; and miconazole, MCZ) upon exposure to ultraviolet (UV) radiation is discussed. First, precursor compounds were immobilized in a silicone support which was further exposed to UV light at two different wavelengths: 254 and 365 nm. After solvent desorption, degradation kinetics of the precursor pharmaceuticals, identification of the arising transformation products (TPs) and evaluation of their time-course were investigated by liquid chromatography (LC) with quadrupole time-of-flight (QTOF) mass spectrometry (MS) detection. The three antimycotics displayed similar stabilities when exposed to 254 nm light; however, CTZ was significantly more stable than MCZ and KTZ when irradiated with the 365 nm lamp. TPs identified in silicone supports resulted from de-chlorination, cleavage, intra-molecular cyclization and hydroxylation reactions. Many of these species were also detected when exposing other solid matrices, such as sand and agricultural soil, previously spiked with target compounds, to UV light. The 50% estimated lethal concentration, calculated using the 48-h Daphnia magna test, for the two main TPs of CTZ and MCZ, at both wavelengths, were lower than those corresponding to the precursor drugs

  2. Light-like noncommutativity, light-front quantization and new light on UV/IR mixing

    International Nuclear Information System (INIS)

    Sheikh-Jabbari, M.M.; Tureanu, A.

    2011-01-01

    We revisit the problem of quantizing field theories on noncommutative Moyal space-time with light-like noncommutativity. To tackle the issues arising from noncommuting and hence nonlocal time, we argue that for this case light-front quantization procedure should be employed. In this appropriate quantization scheme we perform the non-planar loop analysis for the light-like noncommutative field theories. One of the important and peculiar features of light-front quantization is that the UV cutoff of the light-cone Hamiltonian manifests itself as an IR cutoff for the light-cone momentum, p + . Due to this feature, the naive results of covariant quantization for the light-like case allude to the absence of the UV/IR mixing in the light-front quantization. However, by a careful analysis of non-planar loop integrals we show that this is not the case and the UV/IR mixing persists. In addition, we argue in favour of the perturbative unitarity of light-like noncommutative field theories in the light-front quantization scheme.

  3. The imprints of the high light and UV-B stresses in Oryza sativa L. 'Kanchana' seedlings are differentially modulated.

    Science.gov (United States)

    Faseela, Parammal; Puthur, Jos T

    2018-01-01

    High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively

  4. Efficacy of ultraviolet light exposure against survival of Listeria monocytogenes on conveyor belts.

    Science.gov (United States)

    Morey, Amit; McKee, Shelly R; Dickson, James S; Singh, Manpreet

    2010-06-01

    Listeria monocytogenes has been repeatedly isolated from foods and food-processing facilities including food contact surfaces such as conveyor belts (CB). CBs are often difficult to clean and require rigorous sanitation programs for decontamination. Ultraviolet (UV) light has exhibited microbicidal properties on food contact surfaces and this study was conducted to determine the efficacy of UV against L. monocytogenes on CB made of different materials. A four-strain cocktail of L. monocytogenes (serotypes 3A, 4A, 4B, and 4C) was made to give a suspension of approximately 10(7) CFU/mL. CBs made from four different types of materials, (1) Ropanyl DM 8/2 A2 + 04 (belt 1), (2) Volta FRMW-3.0 (belt 2), (3) Volta FRMB-3.0 (belt 3), and (4) Ropanyl DM (belt 4), were inoculated with 1 mL of the four-strain cocktail (approximately 10(7) CFU/mL) of the bacterial suspension. CBs were treated with UV light (254 nm) for 1 and 3 sec at 5.53 and 5.95 mW/cm(2). Three replications of the experiments were conducted. Two-way analysis of variance of survival populations of L. monocytogenes showed that bacterial counts were significantly reduced (p belt types irrespective of UV light intensities and times of exposure. L. monocytogenes populations were reduced (p belts 1, 2, and 3 after exposure to 5.95 mW/cm(2) UV light intensity for 3 sec. L. monocytogenes-inoculated CBs that were exposed to 5.53 mW/cm(2) showed higher (p Belt 4 showed survival populations of L. monocytogenes ranging from 1.42 to 1.73 log(10) CFU/cm(2) after UV light treatment for 1 and 3 sec. UV light can be effectively used to reduce L. monocytogenes contamination on CBs.

  5. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  6. The Use of Ultra-Violet (UV) Light Emitting Diodes (LEDS) in an Advanced Oxidation Process (AOP) with Brilliant Blue FCF as an Indicator

    Science.gov (United States)

    2015-03-26

    LEDs have the potential to replace mercury lamps in many UV processes, as well as open the door to new applications of UV light based on their unique...al. 2007, Autin, Romelot, et al. 2013). UV LEDs in AOPs While most data on AOP experimentation are based on experiments that use mercury lamps ...metaldehyde in solution. Their experiments found that similar UV light exposure levels from UV LEDs and traditional mercury lamps produced similar

  7. Involvement of active oxygen in lipid peroxide radical reaction of epidermal homogenate following ultraviolet light exposure

    International Nuclear Information System (INIS)

    Nishi, J.; Ogura, R.; Sugiyama, M.; Hidaka, T.; Kohno, M.

    1991-01-01

    To elucidate the radical mechanism of lipid peroxidation induced by ultraviolet light (UV) irradiation, an electron spin resonance (ESR) study was made on epidermal homogenate prepared from albino rat skin. The exposure of the homogenate to UV light resulted in an increase in lipid peroxide content, which was proportional to the time of UV exposure. Using ESR spin trapping (dimethyl-1-pyrroline-N-oxide, DMPO), the DMPO spin adduct spectrum of lipid radicals (L.) was measured following UV exposure (DMPO-L.:aN = 15.5 G, aH = 22.7 G), as was the spectrum of DMPO-hydroxyl radical (DMPO-OH, aN = aH = 15.5 G). In the presence of superoxide dismutase, the DMPO spin adduct spectrum of lipid radicals was found to be reduced remarkably. Therefore, it was shown that the generation of the lipid radicals partially involves superoxide anion radicals, in addition to hydroxyl radicals. In the ESR free-radical experiment, an ESR signal appeared at g = 2.0064 when the ESR tube filled with homogenate was exposed to UV light at -150 degrees C. The temperature-dependent change in the ESR free radical signal of homogenate exposed to UV light was observed at temperatures varying from -150 degrees C to room temperature. By using degassed samples, it was confirmed that oxygen is involved in the formation of the lipid peroxide radicals (LOO.) from the lipid radicals (L.)

  8. Enhanced UV exposure on a ski-field compared with exposures at sea level.

    Science.gov (United States)

    Allen, Martin; McKenzie, Richard

    2005-05-01

    Personal erythemal UV monitoring badges, which were developed to monitor the UV exposure of school children, were used to measure UV exposures received by one of the authors (MA) at the Mt Hutt ski-field, in New Zealand. These were then compared with measurements taken at the same times from a nearby sea level site in Christchurch city. The badges were designed to give instantaneous readings of erythemally-weighted (i.e., "sun burning") UV radiation and were cross-calibrated against meteorological grade UV instruments maintained by the National Institute of Water & Atmospheric Research (NIWA). All skiing and calibration days were clear and almost exclusively cloud free. It was found that the UV maxima for horizontal surfaces at the ski-field (altitude approximately 2 km) were 20-30% greater than at the low altitude site. Larger differences between the sites were observed when the sensor was oriented perpendicular to the sun. The personal doses of UV received by a sensor on the skier's lapel during two days of skiing activity were less than those received by a stationary detector on a horizontal surface near sea level. The exposures depended strongly on the time of year, and in mid-October the maximum UV intensity on the ski-field was 60% greater than in mid-September. The UV exposure levels experienced during skiing were smaller than the summer maxima at low altitudes.

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

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

    International Nuclear Information System (INIS)

    Barnes, P.W.; Ballaré, C.L.; Caldwell, M.M.

    1996-01-01

    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

  11. UV emissions from low energy artificial light sources.

    Science.gov (United States)

    Fenton, Leona; Moseley, Harry

    2014-01-01

    Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Sudden Exposure to Solar UV-B Radiation Reduces Net CO2 Uptake and Photosystem I Efficiency in Shade-Acclimated Tropical Tree Seedlings1

    Science.gov (United States)

    Krause, G. Heinrich; Grube, Esther; Virgo, Aurelio; Winter, Klaus

    2003-01-01

    Tree seedlings developing in the understory of the tropical forest have to endure short periods of high-light stress when tree-fall gaps are formed, and direct solar radiation, including substantial UV light, reaches the leaves. In experiments simulating the opening of a tree-fall gap, the response of photosynthesis in leaves of shade-acclimated seedlings (Anacardium excelsum, Virola surinamensis, and Calophyllum longifolium) to exposure to direct sunlight (for 20–50 min) was investigated in Panama (9°N). To assess the effects of solar UV-B radiation (280–320 nm), the sunlight was filtered through plastic films that selectively absorbed UV-B or transmitted the complete spectrum. The results document a strong inhibition of CO2 assimilation by sun exposure. Light-limited and light-saturated rates of photosynthetic CO2 uptake by the leaves were affected, which apparently occurred independently of a simultaneous inhibition of potential photosystem (PS) II efficiency. The ambient UV-B light substantially contributed to these effects. The photochemical capacity of PSI, measured as absorbance change at 810 nm in saturating far-red light, was not significantly affected by sun exposure of the seedlings. However, a decrease in the efficiency of P700 photooxidation by far-red light was observed, which was strongly promoted by solar UV-B radiation. The decrease in PSI efficiency may result from enhanced charge recombination in the reaction center, which might represent an incipient inactivation of PSI, but contributes to thermal dissipation of excessive light energy and thereby to photoprotection. PMID:12586898

  13. Light Conversion and Scattering in UV Protective Textiles

    Directory of Open Access Journals (Sweden)

    Grancarić Ana Marija

    2014-12-01

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

  14. Daily light integral and day light quality: Potentials and pitfalls of nighttime UV treatments on cucumber powdery mildew.

    Science.gov (United States)

    Suthaparan, Aruppillai; Solhaug, Knut Asbjørn; Stensvand, Arne; Gislerød, Hans Ragnar

    2017-10-01

    Nighttime ultraviolet (UV) radiation, if applied properly, has a significant potential for management of powdery mildews in many crop species. In this study, the role of growth light duration, irradiance, a combination of both (daily light integral) and light spectral quality (blue or red) on the efficacy of UV treatments against powdery mildew caused by Podosphaera xanthii and the growth performance of cucumber plants was studied in growth chambers. Increasing daily light integral provided by high-pressure sodium lamps (HPS) decreased efficacy of nighttime UV treatments against P. xanthii, but it increased plant growth. Furthermore, the efficacy of nighttime UV decreased when day length was increased from 16 to 20h at a constant daily light integral. The efficacy of nighttime UV increased if red light was applied after UV treatment, showing the possibility of day length extension without reducing the effect of UV. Increasing the dose of blue light during daytime reduced the efficacy of nighttime UV in controlling the disease, whereas blue deficient growth light (light after nighttime UV reduced its disease control efficacy. This showed the importance of maintaining a minimum of blue light in the growth light before nighttime UV treatment. Findings from this study showed that optimization of nighttime UV for management of powdery mildew is dependent on the spectral composition of the photosynthetically active radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. UV dose-effect relationships and current protection exposure standards

    International Nuclear Information System (INIS)

    Singh, M.S.; Campbell, G.W.

    1982-04-01

    In this paper we have attempted to quantify the health effects in man of uv-radiation exposure of wavelengths from 240 nm to 320 nm. Exposure to uv in this region could result in the formation of skin cancer or premature aging in man. The induction of cancer by uv radiation results from changes in genetic material. We have used the DNA action spectrum coupled with the uv skin cancer data available in the literature to derive the dose-effect relationships. The results are compared against the current uv protection standards

  16. Plant responses to UV and blue light: biochemical and genetic approaches

    International Nuclear Information System (INIS)

    Jenkins, G.I.; Christie, J.M.; Fuglevand, G.; Long, J.C.; Jackson, J.A.

    1995-01-01

    UV and blue light control many aspects of plant growth and development. It is evident that several different photoreceptors mediate responses to UV and blue light, and there are reports of the functional and biochemical characterisation of a putative photoreceptor for phototropism and of the functional and molecular characterisation of the CRY1 photoreceptor, encoded by the Arabidopsis HY4 gene. The CRY1 photoreceptor mediates extension growth and gene expression responses to UV-A/blue light presumably through different or branching signal transduction pathways. Progress has been made in cell physiological and biochemical studies of UV/blue light signal transduction, but much remains to be done to relate candidate UV/blue signal transduction events to particular photoreceptors and responses. The application of a genetic approach in Arabidopsis has been responsible for many advances in understanding UV/blue responses, but further UV-B, UV-A and blue light response mutants need to be isolated. (author)

  17. Disinfection of Spacecraft Potable Water Systems by Photocatalytic Oxidation Using UV-A Light Emitting Diodes

    Science.gov (United States)

    Birmele, Michele N.; O'Neal, Jeremy A.; Roberts, Michael S.

    2011-01-01

    Ultraviolet (UV) light has long been used in terrestrial water treatment systems for photodisinfection and the removal of organic compounds by several processes including photoadsorption, photolysis, and photocatalytic oxidation/reduction. Despite its effectiveness for water treatment, UV has not been explored for spacecraft applications because of concerns about the safety and reliability of mercury-containing UV lamps. However, recent advances in ultraviolet light emitting diodes (UV LEDs) have enabled the utilization of nanomaterials that possess the appropriate optical properties for the manufacture of LEDs capable of producing monochromatic light at germicidal wavelengths. This report describes the testing of a commercial-off-the-shelf, high power Nichia UV-A LED (250mW A365nnJ for the excitation of titanium dioxide as a point-of-use (POD) disinfection device in a potable water system. The combination of an immobilized, high surface area photocatalyst with a UV-A LED is promising for potable water system disinfection since toxic chemicals and resupply requirements are reduced. No additional consumables like chemical biocides, absorption columns, or filters are required to disinfect and/or remove potentially toxic disinfectants from the potable water prior to use. Experiments were conducted in a static test stand consisting of a polypropylene microtiter plate containing 3mm glass balls coated with titanium dioxide. Wells filled with water were exposed to ultraviolet light from an actively-cooled UV-A LED positioned above each well and inoculated with six individual challenge microorganisms recovered from the International Space Station (ISS): Burkholderia cepacia, Cupriavidus metallidurans, Methylobacterium fujisawaense, Pseudomonas aeruginosa, Sphingomonas paucimobilis and Wautersia basilensis. Exposure to the Nichia UV-A LED with photocatalytic oxidation resulted in a complete (>7-log) reduction of each challenge bacteria population in UV-A LEDs and semi

  18. Proposed mechanism of thermoluminescence induced by UV light in the natural CaF2

    International Nuclear Information System (INIS)

    Las, W.C.

    1976-01-01

    The TL response of blue fluorite samples was measured as a function of exposure to 250 nm and 365 nm light. The TL response is linear in the low intensity region, becomes sublinear and has a maximum, decreasing afterwards for higher exposure intensities.The filled deep trap concentration, corresponding to the residual peak, was varied by annealing at different temperatures. The TL response maximum is proportional to this concentration. By exposing the sample to different light intensities a simultaneous decrease of the residual peak and increase of the lower temperature peaks was observed. This behavior suggests a charge transfer process from deep traps to shallow ones. A mathematical model based on this mechanism was proposed by Okuno and Watanabe in order to explain the experimental results. Besides the TL response curves, further data were obtained throughout a cycle of successive exposures to UV light. This experiment showed that the TL peak height presents two distinct decays as a function of the number of successive exposures. The decay is proportional to the probability of releasing charge from deep traps. The model above, however, didn't explain the experimental results. Two modifications were made: one, taking into account the retrapping probability, and the other considering the residual peak as composed of two peaks. From this latter assumption, it was possible to fit simultaneously the TL response curves and the residual peak decays, for 250 nm and 365 nm. The successive exposure curves, however, couldn't be explained in this way. The continuous decrease of the probability of charge release from deep traps as a function of the UV light intensity suggested a continuous distribution of energy levels for the residual peak. This last model fitted all 250 nm experimental data, and the glow curves of the residual peak [pt

  19. Weathering of a carbon nanotube/epoxy nanocomposite under UV light and in water bath: impact on abraded particles

    Science.gov (United States)

    Schlagenhauf, Lukas; Kianfar, Bahareh; Buerki-Thurnherr, Tina; Kuo, Yu-Ying; Wichser, Adrian; Nüesch, Frank; Wick, Peter; Wang, Jing

    2015-11-01

    Weathering processes can influence the surface properties of composites with incorporated nanoparticles. These changes may affect the release behavior of nanoparticles when an abrasion process is applied. Therefore, the influence of two different weathering processes, immersion in water and exposure to UV light, on the properties of abraded particles from a carbon nanotube (CNT)/epoxy nanocomposite was investigated. The investigation included the measurement of the weathering impact on the surface chemistry of the exposed samples, the particle size of abraded particles, the quantity of exposed CNTs in the respirable part of the abraded particles, and the toxicity of abraded particles, measured by in vitro toxicity tests using the THP-1 monocyte-derived macrophages. The results showed that weathering by immersion in water had no influence on the properties of abraded particles. The exposure to UV light caused a degradation of the epoxy on the surface, followed by delamination of an approx. 2.5 μm thick layer. An increased quantity of exposed CNTs in abraded particles was not found; on the contrary, longer UV exposure times decreased the released fraction of CNTs from 0.6% to 0.4%. The toxicity tests revealed that abraded particles from the nanocomposites did not induce additional acute cytotoxic effects compared to particles from the neat epoxy.Weathering processes can influence the surface properties of composites with incorporated nanoparticles. These changes may affect the release behavior of nanoparticles when an abrasion process is applied. Therefore, the influence of two different weathering processes, immersion in water and exposure to UV light, on the properties of abraded particles from a carbon nanotube (CNT)/epoxy nanocomposite was investigated. The investigation included the measurement of the weathering impact on the surface chemistry of the exposed samples, the particle size of abraded particles, the quantity of exposed CNTs in the respirable part of

  20. Luminescence- and nanoparticle-mediated increase of light absorption by photoreceptor cells: Converting UV light to visible light

    OpenAIRE

    Li, Lei; Sahi, Sunil K.; Peng, Mingying; Lee, Eric B.; Ma, Lun; Wojtowicz, Jennifer L.; Malin, John H.; Chen, Wei

    2016-01-01

    We developed new optic devices ? singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light ? for improvement of visual system functions. Tb3+ or Eu3+ singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542?nm or 613?nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals,...

  1. Utilising shade to optimize UV exposure for vitamin D

    Science.gov (United States)

    Turnbull, D. J.; Parisi, A. V.

    2008-06-01

    Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50° can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290-315 nm) radiation without experiencing the high levels of UVA observed in full sun.

  2. Use Of Ultra Violet Light (UV-C) To Reduce Possible Microbial Potential In Cold Storage Rooms Loaded With Sweet Potatoes For Exportation

    International Nuclear Information System (INIS)

    Yassin, Sh.M.; El-Neshawy, S.M.; Aly, A.Z.; Abdel Kader, D.A.

    2012-01-01

    Irradiation with Ultraviolet-c (UV-C) light (254 nm) was applied on sweet potatoes (cv. Abees) as well as the major recovered organisms that are accounted as contaminants in either the internal atmosphere or on sweet potato tuber roots loaded in cold storage room set at 17 degree C and 65-70% RH for 3 months. The captured types of microorganisms from either the internal atmosphere of cold storage room or surfaces of sweet potato tuber roots were fungi, yeast and bacteria with the greatest percentage of fungi that recorded 90% and 70%, respectively. The major individuals of recovered fungi were Penicillium spp., Alternaria alternata, Rhizopus stolonifer, Aspergillus spp., Botrytis cinerea, and Fusarium sp. in descending order of their existence percentages. Upon exposure, the internal atmosphere to UV-C light for one, two and three hours inside cold storage room, a significant reduction of the total number of different types of organisms was obtained with the greatest effect for the three hour-exposure time. Exposure of sweet potatoes to UV-C light at three exposure times (1, 2 and 3 hr) and stored in cold rooms for one month caused a reduction of rot percentages upon natural infection conditions with a full reduction (0 %) when irradiated for 3 hr at the same conditions. Rot percentages were decreased as the exposure time increased. Fruit characteristics in terms of tuber root firmness, shrinking and blemishing of irradiated tuber roots were remarkably maintained than which of the non irradiated ones. UV-C light caused a significant increase in phenol contents in tuber root tissue, while a reverse effect in sugar content was detected; such effects were correlated increasingly or decreasingly with the increase of exposure time. The activity of peroxidase, polyphenoloxidase or poly phenylalanine ammonia lyase (PAL) enzymes in irradiated tuber root tissues were significantly enhanced as the exposure time increased

  3. Abnormal levels of UV-induced unscheduled DNA synthesis in ataxia telangiectasia cells after exposure to ionizing radiation

    International Nuclear Information System (INIS)

    Jaspers, N.G.J.; Nederlandse Centrale Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek, Rijswijk. Medical Biological Lab.); Bootsma, D.

    1982-01-01

    In cultured cells from normal individuals and from patients having ataxia telangiectasia (AT) the rate of unscheduled DNA synthesis (UDS) induced by UV light was investigated by autoradiography. The number of grains in 6 different AT cell strains was similar to that observed in normal cells. Exposure of normal cells to doses of X-rays up to 20 krad had no influence on the rate of UV-induced UDS. In contrast, the UV-induced UDS was significantly modified in AT cells by treatment with X-rays. In AT cell strains that were reported to have reduced levels of γ-ray-induced repair DNA synthesis ('excision-deficient' AT cells) the effect of X-rays on UV-induced UDS was inhibitory, whereas UV-induced UDS was stimulated by X-ray exposure in 'excision-proficient' AT cell strains. Different UV and X-ray dose-response relationships were seen in the two categories of AT cell strains. (orig./AJ)

  4. Time and Place as Modifiers of Personal UV Exposure

    Directory of Open Access Journals (Sweden)

    Brian L. Diffey

    2018-05-01

    Full Text Available It is a common belief that, if we want to limit our sun exposure during outdoor recreational activities and holidays in order to avoid sunburn or reduce our risk of skin cancer, we need to reach for the bottle of sunscreen or cover up with clothing. As important as these measures are, there is another way to enjoy our time outdoors and still benefit from the experience. In this article, we consider the impact of time, place, and behaviour outdoors on our exposure to solar ultraviolet (UV radiation. Some of the simple actions we can take in controlling our UV exposure include being aware of the position of the sun in the sky, understanding how we can use the UV index to guide our outdoor exposure, and the importance of reducing our sun exposure around the middle of the day. Finally we review our preferred holiday activities and destinations, and the influence of outdoor leisure pursuits. By planning where and when we spend our leisure time in the sun, we can maximise our enjoyment whilst limiting our UV exposure.

  5. Time and Place as Modifiers of Personal UV Exposure.

    Science.gov (United States)

    Diffey, Brian L

    2018-05-30

    It is a common belief that, if we want to limit our sun exposure during outdoor recreational activities and holidays in order to avoid sunburn or reduce our risk of skin cancer, we need to reach for the bottle of sunscreen or cover up with clothing. As important as these measures are, there is another way to enjoy our time outdoors and still benefit from the experience. In this article, we consider the impact of time, place, and behaviour outdoors on our exposure to solar ultraviolet (UV) radiation. Some of the simple actions we can take in controlling our UV exposure include being aware of the position of the sun in the sky, understanding how we can use the UV index to guide our outdoor exposure, and the importance of reducing our sun exposure around the middle of the day. Finally we review our preferred holiday activities and destinations, and the influence of outdoor leisure pursuits. By planning where and when we spend our leisure time in the sun, we can maximise our enjoyment whilst limiting our UV exposure.

  6. The optimal UV exposure time for vitamin D3 synthesis and erythema estimated by UV observations in Korea

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2016-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) from spectral UV measurements during 2006-2010. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied to the broadband UV measured by UV-Biometer at 6 sites in Korea Thus, the optimal UV exposure time for vitamin D3 synthesis and erythema was estimated for diurnal, seasonal, and annual scales over Korea. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice

  7. A method for evaluation of UV and biologically effective exposures to plants

    International Nuclear Information System (INIS)

    Paris, A.V.; Southern Queensland Univ., Toowoomba, QLD; Wong, J.C.F.; Galea, V.

    1996-01-01

    This paper presents a method for evaluating the UV and biologically effective exposures to a plant canopy during the irradiation of soybean with supplemental levels of UV radiation in a greenhouse study. The method employs four materials as dosimeters that allow evaluation of the UV spectra. The exposures evaluated at three growth stages were less by factors of 0.44, 0.49 and 0.56 compared to the ambient exposures. At the end of the irradiation period, the ambient biologically effective exposure for generalized plant response was higher by 180% compared to that calculated over the canopy. This is the magnitude of the error in UV studies that provide the ambient exposure as a measure of the UV incident on the plant. Additionally, the difference between the ambient and canopy exposures varied during the growth stages. These results indicate that the dosimetric technique applied to evaluating the UV exposures over a plant canopy is a more accurate representation of the UV exposure incidence on a plant than any obtained by measuring the ambient exposures only. (Author)

  8. Soft, stretchable, epidermal sensor with integrated electronics and photochemistry for measuring personal UV exposures.

    Science.gov (United States)

    Shi, Yunzhou; Manco, Megan; Moyal, Dominique; Huppert, Gil; Araki, Hitoshi; Banks, Anthony; Joshi, Hemant; McKenzie, Richard; Seewald, Alex; Griffin, Guy; Sen-Gupta, Ellora; Wright, Donald; Bastien, Philippe; Valceschini, Florent; Seité, Sophie; Wright, John A; Ghaffari, Roozbeh; Rogers, John; Balooch, Guive; Pielak, Rafal M

    2018-01-01

    Excessive ultraviolet (UV) radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch contains functional layers of ultrathin stretchable electronics and a photosensitive patterned dye that reacts to UV radiation. Color changes in the photosensitive dyes correspond to UV radiation intensity and are analyzed with a smartphone camera. A software application has feature recognition, lighting condition correction, and quantification algorithms that detect and quantify changes in color. These color changes are then correlated with corresponding shifts in UV dose, and compared to existing UV dose risk levels. The soft mechanics of the UV patch allow for multi-day wear in the presence of sunscreen and water. Two evaluation studies serve to demonstrate the utility of the UV patch during daily activities with and without sunscreen application.

  9. Soft, stretchable, epidermal sensor with integrated electronics and photochemistry for measuring personal UV exposures

    Science.gov (United States)

    Shi, Yunzhou; Manco, Megan; Moyal, Dominique; Huppert, Gil; Araki, Hitoshi; Banks, Anthony; Joshi, Hemant; McKenzie, Richard; Seewald, Alex; Griffin, Guy; Sen-Gupta, Ellora; Wright, Donald; Bastien, Philippe; Valceschini, Florent; Seité, Sophie; Wright, John A.; Ghaffari, Roozbeh; Rogers, John; Balooch, Guive

    2018-01-01

    Excessive ultraviolet (UV) radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch contains functional layers of ultrathin stretchable electronics and a photosensitive patterned dye that reacts to UV radiation. Color changes in the photosensitive dyes correspond to UV radiation intensity and are analyzed with a smartphone camera. A software application has feature recognition, lighting condition correction, and quantification algorithms that detect and quantify changes in color. These color changes are then correlated with corresponding shifts in UV dose, and compared to existing UV dose risk levels. The soft mechanics of the UV patch allow for multi-day wear in the presence of sunscreen and water. Two evaluation studies serve to demonstrate the utility of the UV patch during daily activities with and without sunscreen application. PMID:29293664

  10. Soft, stretchable, epidermal sensor with integrated electronics and photochemistry for measuring personal UV exposures.

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    Full Text Available Excessive ultraviolet (UV radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch contains functional layers of ultrathin stretchable electronics and a photosensitive patterned dye that reacts to UV radiation. Color changes in the photosensitive dyes correspond to UV radiation intensity and are analyzed with a smartphone camera. A software application has feature recognition, lighting condition correction, and quantification algorithms that detect and quantify changes in color. These color changes are then correlated with corresponding shifts in UV dose, and compared to existing UV dose risk levels. The soft mechanics of the UV patch allow for multi-day wear in the presence of sunscreen and water. Two evaluation studies serve to demonstrate the utility of the UV patch during daily activities with and without sunscreen application.

  11. Thermoluminescent properties of ZrO2:Mn for UV light dosimetry

    International Nuclear Information System (INIS)

    Rivera M, T.; Azorin N, J.; Falcony G, C.; Martinez, E.; Garcia, M.

    1999-01-01

    The main source of ultraviolet light (UV) to whom is exposed the population is the one coming from the Sun, although exist some artificial sources too. The UV light can be classified in UV A (315-400)nm, in UV B (180-315) nm and UV C (100-180) nm. In this work are presented the results studying in the thermoluminescent characteristics of ZrO 2 : Mn for the UV dosimetry. The studied dosimetric characteristics were: concentration effect of the doping material, erased thermal treatment, posterior thermal treatment to the irradiation, Tl curve, response in function to the wavelength, response in function to the dose and reproducibility. Finally, presenting results highly promisers for the UV light dosimetry. (Author)

  12. UV-A/blue-light responses in algae

    Energy Technology Data Exchange (ETDEWEB)

    Senger, H.; Hermsmeier, D. [Philipps-Universitaet Marburg (Germany)

    1994-12-31

    All life on earth depends on light. A variety of photoreceptors capture the light for a wide range of reactions. Photosynthetic organisms absorb the light necessary for energy transformation and charge separation facilitating photosynthesis. In addition to the bulk pigments there are a great diversity of photoreceptors present in minute concentrations that control development, metabolism and orientation of plants and microorganisms. Based on its spectral absorbance, the well-studied phytochrome system acts in the RL region as well as in the UV-A/BL region where the above mentioned reactions are mediated by a variety of photoreceptors whose natures are largely unknown. Phyllogenetically the UV-A/BL photoreceptors seem to be more ancient pigments that eventually were replaced by the phytochrome system. However, there are many reports that suggest a coaction between the UV-A/BL receptors and the phytochrome system. In several cases the UV-A/BL activation is the prerequisite for the phytochrome reaction. Historically it was the German botanist Julius Sachs who first discovered in 1864 that phototropism in plants was due to BL reactions. It took over 70 years until Bunning (1937) and Galston and Baker (1949) rediscovered the BL response. Since then, an ever-increasing attention has been paid to this effect. Two international conferences in 1979 and 1983 have been entirely dedicated to the BL phenomenon. In this contribution, the general aspect of UV-A/BL responses and especially the responsiveness of algae will be covered. There are numerous review articles covering the various aspects of UV-A/BL action and the photoreceptors involved.

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

    Science.gov (United States)

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

    2018-01-01

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

  14. Enhanced UV light detection using wavelength-shifting properties of Silicon nanoparticles

    International Nuclear Information System (INIS)

    Magill, S.; Xie, J.; Nayfeh, M.; Fizari, M.; Malloy, J.; Maximenko, Y.; Yu, H.

    2015-01-01

    Detection of UV photons is becoming increasingly necessary with the use of noble gases and liquids in elementary particle experiments. Cerenkov light in crystals and glasses, scintillation light in neutrino, dark matter, and rare decay experiments all require sensitivity to UV photons. New sensor materials are needed that can directly detect UV photons and/or absorb UV photons and re-emit light in the visible range measurable by existing photosensors. It has been shown that silicon nanoparticles are sensitive to UV light in a wavelength range around ∼ 200 nm. UV light is absorbed and re-emitted at wavelengths in the visible range depending on the size of the nanoparticles. Initial tests of the wavelength-shifting properties of silicon nanoparticles are presented here that indicate by placing a film of nanoparticles in front of a standard visible-wavelength detecting photosensor, the response of the sensor is significantly enhanced at wavelengths < 320 nm

  15. The effect of UV light on the inactivation of Giardia lamblia and Giardia muris cysts as determined by animal infectivity assay (P-2951-01).

    Science.gov (United States)

    Mofidi, Alexander A; Meyer, Ernest A; Wallis, Peter M; Chou, Connie I; Meyer, Barbara P; Ramalingam, Shivaji; Coffey, Bradley M

    2002-04-01

    This study measured the effect of germicidal ultraviolet (UV) light on Giardia lamblia and Giardia muris cysts, as determined by their infectivity in Mongolian gerbils and CD-1 mice, respectively. Reduction of cyst infectivity due to UV exposure was quantified by applying most probable number techniques. Controlled bench-scale, collimated-beam tests exposed cysts suspended in filtered natural water to light from a low-pressure UV lamp. Both G. lamblia and G. muris cysts showed similar sensitivity to UV light. At 3 mJ/cm2, a dose 10-fold lower than what large-scale UV reactors may be designed to provide, > 2-log10 (99 percent) inactivation was observed. These results, combined with previously published data showing other protozoa and bacteria have similar, high sensitivity to UV light, establish that UV disinfection of drinking water is controlled by viruses which may require over 10-fold more UV dose for the same level of control.

  16. Ultraviolet and short wavelength visible light exposure: why ultraviolet protection alone is not adequate.

    Science.gov (United States)

    Reichow, Alan W; Citek, Karl; Edlich, Richard F

    2006-01-01

    The danger of exposure to ultraviolet (UV) radiation in both the natural environment and artificial occupational settings has long been recognized by national and international standards committees and worker safety agencies. There is an increasing body of literature that suggests that protection from UV exposure is not enough. Unprotected exposure to the short wavelengths of the visible spectrum, termed the "blue light hazard", is gaining acceptance as a true risk to long-term visual health. Global standards and experts in the field are now warning that those individuals who spend considerable time outdoors should seek sun filter eyewear with high impact resistant lenses that provide 100% UV filtration, high levels of blue light filtration, and full visual field lens/frame coverage as provided by high wrap eyewear. The Skin Cancer Foundation has endorsed certain sunglasses as "product[s]...effective [as] UV filter[s] for the eyes and surrounding skin". However, such endorsement does not necessarily mean that the eyewear meets all the protective needs for outdoor use. There are several brands that offer products with such protective characteristics. Performance sun eyewear by Nike Vision, available in both corrective and plano (nonprescription) forms, is one such brand incorporating these protective features.

  17. The EGFR family of receptors sensitizes cancer cells towards UV light

    DEFF Research Database (Denmark)

    Petersen, Steffen B.; Neves Petersen, Teresa; Olsen, Birgitte

    2008-01-01

    A combination of bioinformatics, biophysical, advanced laser studies and cell biology lead to the realization that laser-pulsed UV light stops cancer growth and induces apoptosis. We have previously shown that laser-pulsed UV (LP-UV) illumination of two different skin-derived cancer cell lines both...... bridges. The EGF receptor is often overexpressed in cancers and other proliferative skin disorders, it might be possible to significantly reduce the proliferative potential of these cells making them good targets for laser-pulsed UV-light treatment. The discovery that UV light can be used to open...... disulphide bridges in proteins upon illumination of nearby aromatic amino acids was the first step that lead to the hypothesis that UV light could modulate the structure and therefore the function of these key receptor proteins. The observation that membrane receptors (EGFR) contained exactly the motifs...

  18. Polycyclic aromatic hydrocarbons (PAHs) skin permeation rates change with simultaneous exposures to solar ultraviolet radiation (UV-S).

    Science.gov (United States)

    Hopf, Nancy B; Spring, Philipp; Hirt-Burri, Nathalie; Jimenez, Silvia; Sutter, Benjamin; Vernez, David; Berthet, Aurelie

    2018-05-01

    Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08-0.1 ng/cm 2 /h) compared to without (0.02-0.26 ng/cm 2 /h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97-13.01 ng/cm 2 /h) compared to with UV-S (0.40-6.35 ng/cm 2 /h). Time until permeation (T lags ) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Saeid Nikafshar

    2017-02-01

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

  20. Tolerance of the eriophyid mite Aceria salsolae to UV-A light and implications for biological control of Russian thistle.

    Science.gov (United States)

    Moran, Patrick J; Wibawa, M Irene; Smith, Lincoln

    2017-12-01

    Aceria salsolae (Acari: Eriophyidae) is being evaluated as a candidate biological control agent of Russian thistle (Salsola tragus, Chenopodiaceae), a major invasive weed of rangelands and dryland crops in the western USA. Prior laboratory host range testing under artificial lighting indicated reproduction on non-native Bassia hyssopifolia and on a native plant, Suaeda calceoliformis. However, in field tests in the native range, mite populations released on these 'nontarget' plants remained low. We hypothesized that UV-A light, which can affect behavior of tetranychid mites, would affect populations of the eriophyid A. salsolae differently on the target and nontarget plant species, decreasing the mite's realized host range. Plants were infested with A. salsolae under lamps that emitted UV-A, along with broad-spectrum lighting, and the size of mite populations and plant growth was compared to infested plants exposed only to broad-spectrum light. Russian thistle supported 3- to 55-fold larger mite populations than nontarget plants regardless of UV-A treatment. UV-A exposure did not affect mite populations on Russian thistle or S. calceoliformis, whereas it increased populations 7-fold on B. hyssopifolia. Main stems on nontarget plants grew 2- to 6-fold faster than did Russian thistle under either light treatment. The two nontarget plants attained greater volume under the control light regime than UV-A, but Russian thistle was unaffected. Although Russian thistle was always the superior host, addition of UV-A light to the artificial lighting regime did not reduce the ability of A. salsolae to reproduce on the two nontarget species, suggesting that UV-B or other environmental factors may be more important in limiting mite populations in the field.

  1. Ultraviolet light and ultraviolet light-activated composite resins

    International Nuclear Information System (INIS)

    Murray, G.A.; Yates, J.L.; Newman, S.M.

    1981-01-01

    In a comparison of the UV light--activated composite resins, Estilux was polymerized to a significantly greater depth than the other composite resins. In general, Lee-fill polymerized the least. When comparing the UV light sources, the Lee light and the Duralux light did not significantly differ from each other, but both polymerized the materials tested to a significantly greater depth than the other light sources. Of the two time exposures, 60-second exposure provided a significantly greater depth of polymerization than 20 seconds for each light with each material

  2. UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment

    Science.gov (United States)

    Han, D.; Xia, Y.; Yokota, S.; Kim, J. W.

    2017-12-01

    This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µm are experimentally investigated. In the case of 500 µm KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µm were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm-3) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm-3) fabricated by front UV. This paper proves that the proposed

  3. UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment

    International Nuclear Information System (INIS)

    Han, D; Xia, Y; Yokota, S; Kim, J W

    2017-01-01

    This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µ m are experimentally investigated. In the case of 500 µ m KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µ m were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm −3 ) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm −3 ) fabricated by front UV. This paper proves that the

  4. Ultraviolet radiation levels associated with the use of fluorescent general lighting, UV-A and UV-B lamps in the workplace and home

    International Nuclear Information System (INIS)

    Whillock, M.; Clark, I.E.; McKinlay, A.F.; Todd, C.D.; Mundy, S.J.

    1988-09-01

    A detailed programme of measurements was undertaken by NRPB to determine the ultraviolet irradiance levels likely to be encountered in the workplace and in the home, where fluorescent lighting is used. Assessments have been made of the possible potential risk of the induction of acute effects (photokeratitis, erythema) and of inducing malignant melanoma and non-malignant melanoma skin cancers resulting from exposure to commonly used fluorescent lamps. The optical absorption properties of materials commonly used in diffusers and controllers in commercial and domestic lighting units were also measured. Irradiance data, both weighted (for biological effectiveness) and unweighted, for various lamp types are presented in the report, together with some typical spectral output distributions. The results show that at commonly used illumination levels the UVR emissions from general and special fluorescent lamps presented neither an acute nor a significant chronic hazard. High UV-B emission levels were measured from 'UV-B' lamps used in this study, and exposure to these lamps would result in acute injury within a short time. Great care should be taken in the use of these lamps, and advice should be provided to workers to ensure safe working conditions and procedures. (author)

  5. 207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  8. UV filters for lighting of plants

    Energy Technology Data Exchange (ETDEWEB)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H.K.; Payer, H.D. [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany)

    1994-12-31

    Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The ageing of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

  9. Large area UV light source with a semiconductor cathode

    International Nuclear Information System (INIS)

    Salamov, B. G.; Ciftci, Y. Oe.; Colakoglu, K.

    2002-01-01

    The light emission (LE) in the UV and visible (blue) range generated by a planar gas discharge system (PGDS) with a semiconductor cathode (SC) are studied. New light source offer high-intensity narrow-band emission at various UV and visible wavelengths (330 - 440 nm). Spectra in N 2 is presented, as well as intensity vs pressure curves for the main peaks of the spectrum. The use of source offers several advantages: PGDS can be extremely efficient energy converters transforming and amplifying a relatively low-powered photon flux incident on the receiving surface of the SC into a flux of high-energy particles over extended areas, i.e. electron, ions, photons. Thus, extremely bright UV and visible sources can be built. LE characteristics of the space in the PGDS are complex, depending on the emitting medium and species. By using the IR light to excite the SC of the system, we have shown that the discharge light emission (DLE) of the device with the N 2 in the gap can serve as an efficient source of the UV radiation if gas pressure and electric field are sufficiently high. This is realized due to the effect of the stabilisation of the spatially homogeneous mode of the discharge in a narrow gap with a large emitting area of SC. Special features of DLE render it highly promising for the development of sources with a large area of the emitting surface, high spatial uniformity of UV radiation, and fast dynamics of these devices. This low cost, high power light sources can provide an interesting alternative to conventional UV lamps

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

    Science.gov (United States)

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

    2001-12-01

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

  11. UV Blocking Glass: Low Cost Filters for Visible Light Photocatalytic Assessment

    OpenAIRE

    Dunnill, Charles W.

    2014-01-01

    A number of commercially available art protection products have been compared and assessed for their suitability as UV blocking filters in the application of “visible light” photocatalytic research. Many groups claiming visible light photocatalytic success employ filters to block out stray UV radiation in order to justify that their photocatalysts are indeed visible light photocatalysts and not UV light photocatalysts. These filters come in varying degrees of ability and price and many author...

  12. Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system

    International Nuclear Information System (INIS)

    Muraca, P.; Stout, J.E.; Yu, V.L.

    1987-01-01

    Nosocomial Legionnaires disease can be acquired by exposure to the organism from the hospital water distribution system. As a result, many hospitals have instituted eradication procedures, including hypercholorination and thermal eradication. We compared the efficacy of ozonation, UV light, hyperchlorination, and heat eradication using a model plumbing system constructed of copper piping, brass spigots, Plexiglas reservoir, electric hot water tank, and a pump. Legionella pneumophila was added to the system at 10(7) CFU/ml. Each method was tested under three conditions; (i) nonturbid water at 25 degrees C, (ii) turbid water at 25 degrees C, and (iii) nonturbid water at 43 degrees C. UV light and heat killed L. pneumophila most rapidly and required minimal maintenance. Both UV light and heat (60 degrees C) produced a 5 log kill in less than 1 h. In contrast, both chlorine and ozone required 5 h of exposure to produce a 5 log decrease. Neither turbidity nor the higher temperature of 43 degrees C impaired the efficacy of any of the disinfectant methods. Surprisingly, higher temperature enhanced the disinfecting efficacy of chlorine. However, higher temperature accelerated the decomposition of the chlorine residual such that an additional 120% volume of chlorine was required. All four methods proved efficacious in eradicating L. pneumophila from a model plumbing system

  13. Penetration of UV-A, UV-B, blue, and red light into leaf tissues of pecan measured by a fiber optic microprobe system

    Science.gov (United States)

    Qi, Yadong; Bai, Shuju; Vogelmann, Thomas C.; Heisler, Gordon M.

    2003-11-01

    The depth of light penetration from the adaxial surfaces of the mature leaves of pecan (Carya illinoensis) was measured using a fiber optic microprobe system at four wavelengths: UV-B (310nm), UV-A (360 nm), blue light (430nm), and red light (680nm). The average thickness of the leaf adaxial epidermal layer was 15um and the total leaf thickness was 219um. The patterns of the light attenuation by the leaf tissues exhibited strong wavelength dependence. The leaf adaxial epidermal layer was chiefly responsible for absorbing the UV-A UV-B radiation. About 98% of 310 nm light was steeply attenuated within the first 5 um of the adaxial epidermis; thus, very little UV-B radiation was transmitted to the mesophyll tissues where contain photosynthetically sensitive sites. The adaxial epidermis also attenuated 96% of the UV-A radiation. In contrast, the blue and red light penetrated much deeper and was gradually attenutated by the leaves. The mesophyll tissues attenuated 17% of the blue light and 42% of the red light, which were available for photosynthesis use. Since the epidermal layer absorbed nearly all UV-B light, it acted as an effective filter screening out the harmful radiation and protecting photosynthetically sensitive tissues from the UV-B damage. Therefore, the epidermal function of the UV-B screening effectiveness can be regarded as one of the UV-B protection mechanisms in pecan.

  14. HISTORY OF AMPHIBIAN DECLINE AND THE PAST, PRESENT AND FUTURE RESEARCH WITH UV LIGHT AND OTHER STRESSORS

    Science.gov (United States)

    This talk is an overview of the history of amphibian decline and the lab research and field monitoring results generated by MED and other agencies. Included are the general field observations leading up to our research initiation, UV-light exposures to the Northern Leopard Frog...

  15. Effects of Radon and UV Exposure on Skin Cancer Mortality in Switzerland

    Science.gov (United States)

    de Hoogh, Kees; Hauri, Dimitri; Vicedo-Cabrera, Ana M.; Schindler, Christian; Huss, Anke; Röösli, Martin

    2017-01-01

    Background: Skin cancer incidence in Switzerland is among the highest in the world. In addition to exposure to ultraviolet (UV) radiation, radon alpha particles attached to aerosols can adhere to the skin and potentially cause carcinogenic effects. Objectives: We investigated the effects of radon and UV exposure on skin cancer mortality. Methods: Cox proportional hazard regression was used to study the association between exposures and skin cancer mortality in adults from the Swiss National Cohort. Modeled radon exposure and erythemal-weighted UV dose were assigned to addresses at baseline. Effect estimates were adjusted for sex, civil status, mother tongue, education, job position, neighborhood socioeconomic position, and UV exposure from outdoor occupation. Results: The study included 5.2 million adults (mean age 48 y) and 2,989 skin cancer deaths, with 1,900 indicating malignant melanoma (MM) as the primary cause of death. Adjusted hazard ratios (HR) for MM at age 60 were 1.16 (95% CI: 1.04, 1.29) per 100Bq/m3 radon and 1.11 (1.01, 1.23) per W/m2 in UV dose. Radon effects decreased with age. Risk of MM death associated with residential UV exposure was higher for individuals engaged in outdoor work with UV exposure (HR 1.94 [1.17, 3.23]), though not statistically significantly different compared to not working outdoors (HR 1.09 [0.99, 1.21], p=0.09). Conclusions: There is considerable variation in radon and UV exposure across Switzerland. Our study suggests both are relevant risk factors for skin cancer mortality. A better understanding of the role of the UV radiation and radon exposure is of high public health relevance. https://doi.org/10.1289/EHP825 PMID:28686556

  16. Regulation of the subunit composition of plastidic glutamine synthetase of the wild-type and of the phytochrome-deficient aurea mutant of tomato by blue/UV-A- or by UV-B-light

    International Nuclear Information System (INIS)

    Migge, A.; Carrayol, E.; Hirel, B.; Lohmann, M.; Meya, G.; Becker, T.W.

    1998-01-01

    The photomorphogenetic aurea mutant of tomato severely deficient in spectrophotometrically active phytochromes was used to study the light-regulation of the single-copy nuclear gene encoding plastidic glutamine synthetase (GS-2; EC 6.1.3.2). The de-etiolation of dark-grown aurea mutant seedling cotyledons showed an obligatory dependency on blue light. A limited red light-responsiveness of etiolated aurea cotyledons is, however, retained as seen by the stimulation of both the GS-2 transcript and protein level in the cotyledons of aurea seedlings during growth in red light. The subunits of the octameric GS-2 enzyme were represented by polypeptides with similar electrophoretic mobilities (polypeptides a) in etiolated wild-type or aurea mutant cotyledons. GS-2 proteins with similar apparent molecular masses were also seen in the cotyledons of red light-grown aurea mutant seedlings. In contrast, GS-2 polypeptides with different apparent molecular masses (polypeptides a and b) were detected in the cotyledons of wild-type seedlings grown in red light. This difference indicates that the (post-translational) modification of tomato GS-2 subunit composition is mediated by the photoreceptor phytochrome. The illumination of etiolated wild-type or aurea cotyledons with UV-A- or UV-B-light light resulted in an increase in both the GS-2 transcript and protein level. Following illumination of etiolated wild-type seedlings with UV-A-light, the relative proportion of the GS-2 polypeptides a and b was similar than upon irradiation with blue light but different than after exposure to UV-B- or red light. This result suggests the involvement of a blue/ UV-A-light-specific photoreceptor in the regulation of tomato GS-2 subunit composition. (author)

  17. Fluorescent minerals - A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments

    Science.gov (United States)

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark.

  18. UV Blocking Glass: Low Cost Filters for Visible Light Photocatalytic Assessment

    Directory of Open Access Journals (Sweden)

    Charles W. Dunnill

    2014-01-01

    Full Text Available A number of commercially available art protection products have been compared and assessed for their suitability as UV blocking filters in the application of “visible light” photocatalytic research. Many groups claiming visible light photocatalytic success employ filters to block out stray UV radiation in order to justify that their photocatalysts are indeed visible light photocatalysts and not UV light photocatalysts. These filters come in varying degrees of ability and price and many authors fail to correctly characterise their filters in individual papers. The use of effective filters to prevent both false positive and false negative results is important to maintain scientific rigor and create accurate understanding of the subject. The optimum UV filter would have the highest UV blocking properties (<390 nm and simultaneously the highest visible light transmission (390–750 nm. Single and double layers of each of the glass products were assessed as well as laminate products. The conclusions show an inexpensive and highly effective setup for the conduction of visible light photochemistry that should be incorporated as a standard part in any researcher’s work where the claim of visible light activity is made.

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

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  20. Sunscreen for fish: co-option of UV light protection for camouflage.

    Directory of Open Access Journals (Sweden)

    Kaspar P Mueller

    Full Text Available Many animals change their body pigmentation according to illumination of their environment. In aquatic vertebrates, this reaction is mediated through aggregation or dispersion of melanin-filled vesicles (melanosomes in dermal pigment cells (melanophores. The adaptive value of this behavior is usually seen in camouflage by allowing the animal to visually blend into the background. When exposed to visible light from below, however, dark-adapted zebrafish embryos at the age of 2 days post fertilization (dpf surprisingly display dispersal instead of aggregation of melanosomes, i.e. their body coloration becomes dark on a bright background. Melanosomes of older embryos and early larvae (3-5 dpf on the other hand aggregate as expected under these conditions. Here we provide an explanation to this puzzling finding: Melanosome dispersion in larvae 3 dpf and older is efficiently triggered by ultraviolet (UV light, irrespective of the visual background, suggesting that the extent of pigmentation is a trade-off between threats from predation and UV irradiation. The UV light-induced dispersion of melanosomes thereby is dependent on input from retinal short wavelength-sensitive (SWS cone photoreceptors. In young embryos still lacking a functional retina, protection from UV light predominates, and light triggers a dispersal of melanosomes via photoreceptors intrinsic to the melanophores, regardless of the actual UV content. In older embryos and early larvae with functional retinal photoreceptors in contrast, this light-induced dispersion is counteracted by a delayed aggregation in the absence of UV light. These data suggest that the primary function of melanosome dispersal has evolved as a protective adaption to prevent UV damage, which was only later co-opted for camouflage.

  1. Sunscreen for Fish: Co-Option of UV Light Protection for Camouflage

    Science.gov (United States)

    Mueller, Kaspar P.; Neuhauss, Stephan C. F.

    2014-01-01

    Many animals change their body pigmentation according to illumination of their environment. In aquatic vertebrates, this reaction is mediated through aggregation or dispersion of melanin-filled vesicles (melanosomes) in dermal pigment cells (melanophores). The adaptive value of this behavior is usually seen in camouflage by allowing the animal to visually blend into the background. When exposed to visible light from below, however, dark-adapted zebrafish embryos at the age of 2 days post fertilization (dpf) surprisingly display dispersal instead of aggregation of melanosomes, i.e. their body coloration becomes dark on a bright background. Melanosomes of older embryos and early larvae (3–5 dpf) on the other hand aggregate as expected under these conditions. Here we provide an explanation to this puzzling finding: Melanosome dispersion in larvae 3 dpf and older is efficiently triggered by ultraviolet (UV) light, irrespective of the visual background, suggesting that the extent of pigmentation is a trade-off between threats from predation and UV irradiation. The UV light-induced dispersion of melanosomes thereby is dependent on input from retinal short wavelength-sensitive (SWS) cone photoreceptors. In young embryos still lacking a functional retina, protection from UV light predominates, and light triggers a dispersal of melanosomes via photoreceptors intrinsic to the melanophores, regardless of the actual UV content. In older embryos and early larvae with functional retinal photoreceptors in contrast, this light-induced dispersion is counteracted by a delayed aggregation in the absence of UV light. These data suggest that the primary function of melanosome dispersal has evolved as a protective adaption to prevent UV damage, which was only later co-opted for camouflage. PMID:24489905

  2. Photoreactivation of ultraviolet light-induced sister chromatid exchanges in potorous cells

    International Nuclear Information System (INIS)

    Ishizaki, K.; Nikaido, O.; Takebe, H.

    1980-01-01

    Exposure to visible light after UV-irradiation showed a remarkable effect on UV-induced sister chromatid exchanges (SCEs). After 6-h exposure to visible light (3 x 10 5 J/m 2 ), two-thirds of the UV-induced SCEs were prevented, confirming Kato's findings. (Nature 249, 552-3, 1974) Exposure to visible light before UV irradiation had no effect. This effect of visible light on UV-induced CSEs was temperature dependent, suggesting the presence of enzymatic photoreactivation. (author)

  3. Action of UV-A and blue light on enzymes activity and accumulation of lipid peroxidation products in attached and detached frog retinas

    Science.gov (United States)

    Lapina, Victoria A.; Doutsov, Alexander E.

    1994-07-01

    The effect of the UV-A and blue light on the accumulation of lipid peroxidation products and activities of succinate dehydrogenase and superoxide dismutase in the retina was examined in eye cup model of dark and light adapted frogs R. temporaria. Retinas were exposed to UV-A radiation (8 mW/cm2) and blue light (10 to 150 mW/cm2) for periods from 5 min to 1 hr. We have measured TBA-active products both in the retina homogenates and in the reaction media. Enzyme activities was measured in the retina homogenates only. The measurements revealed a significant increase in the endogenous and exogenous forms of lipid peroxidation products in the retina of dark adapted frog (1.6+/- 0.4; 1.4+/- 0.3 nmole TBA-active products per mg protein, respectively) compared to light adapted (0.85+/- 0.16; 0.32+/- 0.06 nmole TBA-active products per mg protein, respectively). In the same conditions succinate dehydrogenase activity was decline more than 50% but superoxide dismutase activity didn't decrease. Disorganized inner and outer segments were observed after 40 min exposures. No light microscopic changes were detected after 5 min exposures. Light damage was significantly higher in the retina of dark adapted frog. The results indicate that the retina from eye cup of dark adapted frog is more susceptible to UV-A and blue light damages.

  4. The effects of UV light on calcium metabolism in ball pythons (Python regius).

    Science.gov (United States)

    Hedley, J; Eatwell, K

    2013-10-12

    Despite the popularity of keeping snakes in captivity, there has been limited investigation into the effects of UV radiation on vitamin D levels in snakes. The aim of this study was to investigate the effects of UV-b radiation on plasma 25-hydroxyvitamin D3 levels and ionised calcium concentrations in ball pythons (Python regius). Blood samples were taken from 14 ball pythons, which had never been exposed to UV-b light, to obtain baseline 25-hydroxyvitamin D3 levels and ionised calcium concentrations. Blood samples were then taken again from the same snakes 70 days later after one group (Group 1, n=6 females) were exposed to UV-b radiation daily, and the other group (Group 2, n=5 males and 3 females) were exposed to no UV-b radiation. Mean±sd 25-hydroxyvitamin D3 levels on day 0 in Group 1 were 197±35 nmol/l, and on day 70 were 203.5±13.8 nmol/l. Mean±sd 25-hydroxyvitamin D3 levels in Group 2 on day 0 were 77.7±41.5 nmol/l, and on day 70 were 83.0±41.9 nmol/l. Mean±sd ionised calcium levels at day 0 were 1.84±0.05 mmol/l for Group 1, and on day 70 were 1.78±0.07 mmol/l. Mean±sd ionised calcium levels at day 0 were 1.79±0.07 mmol/l for Group 2, and on day 70 were 1.81±0.05 mmol/l. No association was demonstrated between exposure to UV-b radiation and plasma 25-hydroxyvitamin D3 and ionised calcium concentrations. These results may provide baseline parameters for future studies in this and other snake species to determine ability to utilise UV-b light for vitamin D production.

  5. Solar UV exposure among outdoor workers in Denmark measured with personal UV-B dosimeters

    DEFF Research Database (Denmark)

    Grandahl, Kasper; Mortensen, Ole Steen; Sherman, David Zim

    2017-01-01

    radiation exposure are needed to help resolve this problem. This can be done using personal ultraviolet radiation dosimeters. Methods: We consider technical and practical feasibility of measuring individual solar ultraviolet exposure at work and leisure in professions with different á priori temporal high......-level outdoor worktime, using aluminium gallium nitride (AlGaN) photodiode detector based personal UV-B dosimeters. Essential technical specifications including the spectral and angular responsivity of the dosimeters are described and pre-campaign dosimeter calibration applicability is verified. The scale...... with our specialist knowledge as occupational physicians. Conclusions: Large-scale use of personal UV-B dosimeters for measurement of solar ultraviolet radiation exposure at work and leisure in Denmark is indeed feasible from a technical and practical viewpoint. Samples of exposure data shown support...

  6. Growth under visible light increases conidia and mucilage production and tolerance to UV-B radiation in the plant pathogenic fungus Colletotrichum acutatum.

    Science.gov (United States)

    de Menezes, Henrique D; Massola, Nelson S; Flint, Stephan D; Silva, Geraldo J; Bachmann, Luciano; Rangel, Drauzio E N; Braga, Gilberto U L

    2015-01-01

    Light conditions can influence fungal development. Some spectral wavebands can induce conidial production, whereas others can kill the conidia, reducing the population size and limiting dispersal. The plant pathogenic fungus Colletotrichum acutatum causes anthracnose in several crops. During the asexual stage on the host plant, Colletototrichum produces acervuli with abundant mucilage-embedded conidia. These conidia are responsible for fungal dispersal and host infection. This study examined the effect of visible light during C. acutatum growth on the production of conidia and mucilage and also on the UV tolerance of these conidia. Conidial tolerance to an environmentally realistic UV irradiance was determined both in conidia surrounded by mucilage on sporulating colonies and in conidial suspension. Exposures to visible light during fungal growth increased production of conidia and mucilage as well as conidial tolerance to UV. Colonies exposed to light produced 1.7 times more conidia than colonies grown in continuous darkness. The UV tolerances of conidia produced under light were at least two times higher than conidia produced in the dark. Conidia embedded in the mucilage on sporulating colonies were more tolerant of UV than conidia in suspension that were washed free of mucilage. Conidial tolerance to UV radiation varied among five selected isolates. © 2014 The American Society of Photobiology.

  7. Stability of the Stevia-Derived Sweetener Rebaudioside A in Solution as Affected by Ultraviolet Light Exposure.

    Science.gov (United States)

    Zhang, Jiewen; Bell, Leonard N

    2017-04-01

    Rebaudioside A is a natural noncaloric high-potency sweetener extracted from the leaves of Stevia rebaudiana. With rebaudioside A use increasing in foods, understanding the factors affecting its stability is necessary. This project evaluated the degradation rate constants of rebaudioside A in water, 0.1 M phosphate buffer, and 0.1 M citrate buffer at pH 3 and 7 as a function of ultraviolet (UV) light intensity (365 nm, 0 μW/cm 2 for dark conditions, 27 μW/cm 2 for low intensity, and 190 μW/cm 2 for high intensity) at 32.5 °C. Rebaudioside A stability was adversely affected by light exposure. The pseudo-1st-order degradation rate constants increased significantly (P < 0.05) with increasing light intensity in all solutions. Under dark conditions, rebaudioside A in phosphate buffers was more susceptible to breakdown than in water and citrate buffers at both pH levels. However, exposure to UV light resulted in rebaudioside A degradation occurring approximately 10 times faster in citrate than in phosphate buffers at both pH levels. The sensitivity of rebaudioside A to UV light was greater in citrate buffers than in water or phosphate buffers. The use of light-protective packaging for beverages containing rebaudioside A will improve its stability. © 2017 Institute of Food Technologists®.

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  9. Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp

    Science.gov (United States)

    Muramoto, Yoshihiko; Kimura, Masahiro; Nouda, Suguru

    2014-06-01

    Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs.

  10. Uveal melanoma in relation to ultraviolet light exposure and host factors.

    Science.gov (United States)

    Holly, E A; Aston, D A; Char, D H; Kristiansen, J J; Ahn, D K

    1990-09-15

    We conducted a case-control interview study among 1277 subjects (407 patients, 870 controls selected by using random digit dial) in 11 western United States to determine whether uveal melanoma and cutaneous melanoma shared common risk factors. After adjustment for other factors, the risk of uveal melanoma was increased for those with green, gray, or hazel eyes [relative risk (RR) = 2.5, P less than 0.001] or blue eyes (RR = 2.2, P less than 0.001) when compared to brown. A tendency to sunburn after 0.5 h midday summer sun exposure increased risk for uveal melanoma (burn with tanning RR = 1.5, P = 0.02; burn with little tanning RR = 1.8, P less than 0.001; burn with no tanning RR = 1.7, P = 0.002); as did exposure to UV or black lights (RR = 3.7, P = 0.003); and welding burn, sunburn of the eye, or snow blindness (RR = 7.2, P less than 0.001). An association with uveal melanoma was also noted with an increasing number of large nevi (P = 0.04 for trend), although the individual risk estimates were not remarkable. These data suggest that host factors and exposure to UV light are risk factors for uveal melanoma.

  11. The Effect of Nitrogen-Doped ATO Nanotubes on Radical Multiplication of Buffer Media by Visible Light Photocatalysis Rather UV

    Directory of Open Access Journals (Sweden)

    Kan-Hung Hu

    2012-01-01

    Full Text Available The use of TiO2 in photodynamic therapy for the treatment of cancer has generally been studied in cultured cancer cells in serum-containing RPMI 1640 medium under visible light application rather than ultraviolet (UV light. An ordered channel array of N-doped anodic titanium dioxide (ATO has been successfully made for visible light application. ATO nanotubes in the anatase form with a length of 10 μm are more effective than nanotubes of 1.8 μm in length as a photocatalyst for radical multiplication in buffer solution by generating hydroxyl radicals and superoxide radical anions under UV-A exposure. Only the N-doped ATO is applicable to visible light photocatalysis for radical multiplication in RPMI 1640+1% FBS and acrylamide, a free radical carrier.

  12. Physiological limit of the daily endogenous cholecalciferol synthesis from UV light in cattle

    DEFF Research Database (Denmark)

    Hymøller, L.; Jensen, S. K.; Kaas, P.

    2017-01-01

    The link between UV light (sunlight) and endogenous cholecalciferol (vitamin D3) synthesis in the skin of humans has been known for more than a 100 years, since doctors for the first time successfully used UV light to cure rickets in children. Years later, it was shown that UV light also had...

  13. Is the photoactive yellow protein a UV-B/blue light photoreceptor?

    NARCIS (Netherlands)

    Carroll, E. C.; Hospes, M.; Valladares, C.; Hellingwerf, K.J.; Larsen, D.S.

    2011-01-01

    UV light below 300 nm is shown to generate the first photocycle intermediate in the blue light photoreceptor Photoactive Yellow Protein. Fluorescence and ultrafast transient absorption measurements indicate two excitation pathways: UV-B absorption by the chromophore and Fluorescence Resonant Energy

  14. In vivo activation of human immunodeficiency virus type 1 long terminal repeat by UV type A (UV-A) light plus psoralen and UV-B light in the skin of transgenic mice

    OpenAIRE

    Morrey, John D; Bourn, S M; Bunch, T D; Jackson, M K; Sidwell, R W; Barrows, L R; Daynes, R A; Rosen, C A

    1991-01-01

    UV irradiation has been shown to activate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in cell culture; however, only limited studies have been described in vivo. UV light has been categorized as UV-A (400 to 315 nm), -B (315 to 280 nm), or -C (less than 280 nm); the longer wavelengths are less harmful but more penetrative. Highly penetrative UV-A radiation constitutes the vast majority of UV sunlight reaching the earth's surface but is normally harmless. UV-B ir...

  15. UV radiation: sources, effects and risks of human and environmental exposure

    International Nuclear Information System (INIS)

    Eggink, G.J.; Slaper, H.

    1992-01-01

    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)

  16. Luminescence- and nanoparticle-mediated increase of light absorption by photoreceptor cells: Converting UV light to visible light.

    Science.gov (United States)

    Li, Lei; Sahi, Sunil K; Peng, Mingying; Lee, Eric B; Ma, Lun; Wojtowicz, Jennifer L; Malin, John H; Chen, Wei

    2016-02-10

    We developed new optic devices - singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light - for improvement of visual system functions. Tb(3+) or Eu(3+) singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542 nm or 613 nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals, retinal degeneration mutants, and light-induced photoreceptor cell degeneration models), the use of Tb(3+) or Eu(3+) doped luminescence glass or CdS-QD coated glass lenses provide additional visible light to the rod and cone photoreceptor cells, and thereby improve the visual system functions. The data provide proof-of-concept for the future development of optic devices for improvement of visual system functions in patients who suffer from photoreceptor cell degeneration or related retinal diseases.

  17. Exposure of mice to cigarette smoke and/or light causes DNA alterations in heart and aorta

    International Nuclear Information System (INIS)

    Izzotti, Alberto; D'Agostini, Francesco; Balansky, Roumen; Degan, Paolo; Pennisi, Tanya M.; Steele, Vernon E.; De Flora, Silvio

    2008-01-01

    Cigarette smoke (CS) is a major risk factor for cardiovascular diseases, cancer, and other chronic degenerative diseases. UV-containing light is the most ubiquitous DNA-damaging agent existing in nature, but its possible role in cardiovascular diseases had never been suspected before, although it is known that mortality for cardiovascular diseases is increased during periods with high temperature and solar irradiation. We evaluated whether exposure of Swiss CD-1 mice to environmental CS (ECS) and UV-C-covered halogen quartz lamps, either individually or in combination, can cause DNA damage in heart and aorta cells. Nucleotide alterations were evaluated by 32 P postlabeling methods and by HPLC-electrochemical detection. The whole-body exposure of mice to ECS considerably increased the levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and of bulky DNA adducts in both heart and aorta. Surprisingly, even exposure to a light that simulated solar irradiation induced oxidatively generated damage in both tissues. The genotoxic effects of UV light in internal organs is tentatively amenable to formation of unidentified long-lived mutagenic products in the skin of irradiated mice. Nucleotide alterations were even more pronounced when the mice were exposed to smoke and/or light during the first 5 weeks of life rather than during adulthood for an equivalent period of time. Although the pathogenetic meaning is uncertain, DNA damage in heart and aorta may tentatively be related to cardiomyopathies and to the atherogenesis process, respectively

  18. Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp

    International Nuclear Information System (INIS)

    Muramoto, Yoshihiko; Kimura, Masahiro; Nouda, Suguru

    2014-01-01

    Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs. (invited article)

  19. Fluorescent minerals--A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments.

    Science.gov (United States)

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  20. Practical considerations in the use of UV light for drinking water disinfection

    International Nuclear Information System (INIS)

    Jeyanayagam, S.; Cotton, C.

    2002-01-01

    Ultraviolet (UV) light was discovered approximately 150 years ago. The first commercial UV lamp was made in the early 1900s soon followed by the manufacture of the quartz sleeve. These technological advances allowed the first application of UV light for water disinfection in 1907 in France. In the mid 1980s, UV disinfection was named as a Best available technology (BAT) for wastewater disinfection in the United States. Fueled by the recent findings that UV disinfection can inactivate key pathogens at cost effective UV doses, the drinking water industry in North America is closely investigating its application in large installations. (author)

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  2. Studies into the transplantation biology of ultraviolet light-induced tumors

    International Nuclear Information System (INIS)

    Daynes, R.A.; Spellman, C.W.; Woodward, J.G.; Stewart, D.A.

    1977-01-01

    The majority of skin tumors induced in mice by ultraviolet (uv) light are rejected when implanted into normal syngeneic recipients. Subcarcinogenic levels of uv light exposure render the normally resistant mice susceptible to tumor challenge. The immunoregulatory effect of uv light appears to be additive, since the growth rate of a tumor transplant is dependent upon the length of uv exposure administered prior to implantation. This suppressive influence does not appear to be directly mediated by the uv light, because the amputation of uv-irradiated tail skin allows for a retention of tumor resistance in otherwise tumor-susceptible hosts. uv-irradiated mice could also be immunized against uv tumors, which suggests that immune recognition of tumor-specific transplantation antigens has not been inhibited. The ability of uv exposure to alter normal immunological reactivity to uv-induced tumors is possibly an integral factor in the mechanism underlying uv carcinogenesis

  3. The injury and cumulative effects on human skin by UV exposure from artificial fluorescence emission.

    Science.gov (United States)

    Tian, Yan; Liu, Wei; Niu, TianHui; Dai, CaiHong; Li, Xiaoxin; Cui, Caijuan; Zhao, Xinyan; E, Yaping; Lu, Hui

    2014-01-01

    The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low-dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low-dose group with a cumulative dose of 50 J cm(-2) which was equivalent to irradiation of the face during indoor work for 1.5 years; and high-dose group with 1000 J cm(-2) cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low-dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP-1, p53 and SIRT1 expression was also increased. Long-term exposure of low-dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention. © 2014 The American Society of Photobiology.

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

    Science.gov (United States)

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

    2015-05-01

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

  5. Ultraviolet safety assessments of insect light traps.

    Science.gov (United States)

    Sliney, David H; Gilbert, David W; Lyon, Terry

    2016-01-01

    Near-ultraviolet (UV-A: 315-400 nm), "black-light," electric lamps were invented in 1935 and ultraviolet insect light traps (ILTs) were introduced for use in agriculture around that time. Today ILTs are used indoors in several industries and in food-service as well as in outdoor settings. With recent interest in photobiological lamp safety, safety standards are being developed to test for potentially hazardous ultraviolet emissions. A variety of UV "Black-light" ILTs were measured at a range of distances to assess potential exposures. Realistic time-weighted human exposures are shown to be well below current guidelines for human exposure to ultraviolet radiation. These UV-A exposures would be far less than the typical UV-A exposure in the outdoor environment. Proposals are made for realistic ultraviolet safety standards for ILT products.

  6. CR-39 (PADC) Reflection and Transmission of Light in the Ultraviolet-Near-Infrared (UV-NIR) Range.

    Science.gov (United States)

    Traynor, Nathan B J; McLauchlin, Christopher; Dodge, Kenneth; McGarrah, James E; Padalino, Stephen J; McCluskey, Michelle; Sangster, T C; McLean, James G

    2018-04-01

    The spectral reflection (specular and diffuse) and transmission of Columbia Resin 39 (CR-39) were measured for incoherent light with wavelengths in the range of 200-2500 nm. These results will be of use for the optical characterization of CR-39, as well as in investigations of the chemical modifications of the polymer caused by ultraviolet (UV) exposure. A Varian Cary 5000 was used to perform spectroscopy on several different thicknesses of CR-39. With proper analysis for the interdependence of reflectance and transmittance, results are consistent across all samples. The reflectivity from each CR-39-air boundary reveals an increase in the index of refraction in the near-UV. Absorption observations are consistent with the Beer-Lambert law. Strong absorption of UV light of wavelength shorter than 350 nm suggests an optical band gap of 3.5 eV, although the standard analysis is not conclusive. Absorption features observed in the near infrared are assigned to molecular vibrations, including some that are new to the literature.

  7. UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report

    International Nuclear Information System (INIS)

    Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

    2012-01-01

    UV-dependent vitamin D 3 synthesis - balancing of UV exposure time and the production of an optimal vitamin D 3 status in men The adverse health effects on human skin and eyes by UV radiation have been well known for years. They are known to the public, too. Increased exposures by the UV-B fraction of solar radiation cause e.g. sun burn as an acute skin reaction or an increased risk on skin cancer as a chronic effect. Radiation of the same spectral UV-B range is necessary to induce the essential vitamin D metabolism in men. The UV-induced vitamin D synthesis in the skin supplies the body with more than 90 % while our typical nutrition contributes no more than 10 %. These photobiological effects are diametrically opposed. Therefore, up to now there are contradictory recommendations to the public concerning the health effects of solar UV exposure. The aim of this research project was to evaluate the quantitative and qualitative relations of UV exposure and the vitamin D status in men taking into account different conditions in the population. In result, well-balanced recommendations on optimal UV exposures for the different fractions of the population should be elaborated, realizing health protection aspects against detrimental UV effects. A literature survey (updated in 2011) summarizes the current knowledge on the vitamin D metabolism, on the effects of the hormone vitamin D and on the stage of the current discussion on the optimal vitamin D status. In a number of studies of this project the effects of UV exposure on the vitamin D status (25OH-vitamin D 3 und 1,25OH-vitamin D 3 ) were investigated. Exposure parameters were the photobiologically effective UV dose (with respect to the minimal erythema dose MED = individual sun burn dose in each investigated volunteer) and the extent of the exposed skin area: face and hands (like everyday conditions) or whole body respectively. Serial UV exposures were applied by natural solar UV radiation or by simulated solar

  8. Photomorphogenetic responses to UV radiation and short-term red light in lettuce seedlings

    International Nuclear Information System (INIS)

    Kobzar, E.F.; Kreslavski, V.D.; Muzafarov, E.N.

    1998-01-01

    Effects of red light (R), far-red light (FR) and UV radiation on growth and greening of lettuce seedlings (Latuca sativa L., cv. Berlinskii) have been investigated. UV-B and UV-C inhibited hypocotyl elongation and stimulated cotyledonary growth. R in combination with UV-B and UV-C partly eliminated these effects, but FR increased those and reversed the R effect. Chlorophyll accumulation was inhibited by UV-B and UV-C. In comparison with cotyledonary growth, R strengthened the UV inhibitory effect, and FR reversed this effect of R. Thus, UV and phytochrome system modify the effects of each other on hypocotyl and leaf growth in lettuce seedlings depending on the level of active phytochrome formed

  9. Cytotoxic, mutagenic and carcinogenic properties of ultraviolet radiation : shining light on photolesions

    NARCIS (Netherlands)

    J. Jans (Judith)

    2003-01-01

    textabstractExposure to ultraviolet light (UV light) poses a serieus threat to human health. An altered life style (holidays in the sun, tanning devices) has led to increased exposure to UV light in the Western population. UV light damages the DNA, the carrier of genetic information, which can

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

    Science.gov (United States)

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

    2012-02-01

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

  11. Conformational Effects of UV Light on DNA Origami.

    Science.gov (United States)

    Chen, Haorong; Li, Ruixin; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

    2017-02-01

    The responses of DNA origami conformation to UV radiation of different wavelengths and doses are investigated. Short- and medium-wavelength UV light can cause photo-lesions in DNA origami. At moderate doses, the lesions do not cause any visible defects in the origami, nor do they significantly affect the hybridization capability. Instead, they help relieve the internal stress in the origami structure and restore it to the designed conformation. At high doses, staple dissociation increases which causes structural disintegration. Long-wavelength UV does not show any effect on origami conformation by itself. We show that this UV range can be used in conjunction with photoactive molecules for photo-reconfiguration, while avoiding any damage to the DNA structures.

  12. In-vivo data on the influence of tobacco smoke and UV light on murine skin.

    Science.gov (United States)

    Pavlou, P; Rallis, M; Deliconstantinos, G; Papaioannou, G; Grando, S A

    2009-01-01

    Inhaled tobacco smoke comes in direct contact with few organs such as mouth, lungs, and stomach. Cigarette smoke (CS) in lungs has been extensively studied. However, limited data exist on its effect on skin, and there are no long-term experimental studies suggesting toxic effects on skin. Even though it is generally accepted that CS is among the main factors of skin aging, the number of experimental studies showing this aging effect is limited. We hereby studied the effect of long-term exposure to CS on the skin of hairless mice in combination with or without ultraviolet (UV) light. In addition, we investigated potential skin protection by a potent antioxidant namely procyanidine-rich French maritime pine bark extract (PBE) pycnogenol. Male and female hairless SKH-2 mice were exposed for 10 months to tobacco smoke and/or UV light in vivo, and their effects on skin were investigated. Some biophysical parameters such as development of erythema, transepidermal water loss (TEWL), and skin elasticity were measured. The results show that UV and CS may be acting synergistically, as shown by the enhanced TEWL, erythema values, epitheliomas, and squamous cell carcinomas (SCCs) observed, whereas PBE seems to protect skin against SCC.

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

    Science.gov (United States)

    Bohrerova, Z; Linden, K G

    2006-11-01

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

  14. People with Increased Risk of Eye Damage from UV Light

    Science.gov (United States)

    ... With Increased Risk of Eye Damage from UV Light Leer en Español: Algunas Personas Están en Mayor Riesgo de Sufrir Daño Ocular por los Rayos UV Written By: Shirley Dang Apr. 30, 2014 Everyone of any age and any degree of skin pigmentation is susceptible to UV damage. Children are ...

  15. Effects of UV light and chromium ions on wood flavonoids

    International Nuclear Information System (INIS)

    Molnárné Hamvas, L.; Németh, K.; Stipta, J.

    2003-01-01

    The individual and simultaneous effect of UV light and chromium ions was investigated by spectrophotometric methods on inert surfaces impregnated with quercetin or robinetin. The UV-VIS spectra of the silica gel plates impregnated with these flavonoids were modified characteristically after irradiating ultraviolet light. Even a half an hour of irradiation has caused irreversible changes in the molecule structure. A certain chemical - presumably complexation - was concluded from the change of spectral bands assigned to flavonoids when impregnated with chromic ions. Hexavalent chromium caused more complex changes in the absorption spectra. The differences in the spectra could indicate either the oxidation and decomposition of flavonoids, or some kind of coordination process and the reduction of hexavalent chromium. The simultaneous application of UV light and chromium ions caused more pronounced effects. The complexation process between chromium(III) and flavonoid was completed

  16. In vivo measurements of daily UV exposure of human anterior teeth using CaF{sub 2}:Tb,Sm as a thermoluminescence dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Saito, W., E-mail: saito-wataru@tsurumi-u.ac.j [Department of Operative Dentistry, Tsurumi University, School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama (Japan); Ikejima, I. [Department of Operative Dentistry, Tsurumi University, School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama (Japan); Fukuda, Y. [Department of Urban Environment, Faculty of Human Environment, Osaka Sangyo University, 3-1-1, Nakagaito, Daito, Osaka (Japan); Momoi, Y. [Department of Operative Dentistry, Tsurumi University, School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama (Japan)

    2011-03-15

    Ultraviolet radiation (UV) has been indicated as one of the causes of discoloration of dental materials yet the standard requires that dental polymers be irradiated with light from a xenon lamp, which includes UV, to evaluate their color stability. It is doubtful that dental polymers in the mouth are exposed to large energy of UV on a daily basis, but there have been no reports concerning exposure. In the present study, we used thermoluminescence (TL) from sintered CaF{sub 2}:Tb,Sm, which is highly sensitive to UV, to measure the daily energy of UV exposure to the labial surface of the maxillary anterior teeth, which are regarded as receiving the maximum exposure among oral tissues. We produced disks of CaF{sub 2} co-doped with Tb{sub 4}O{sub 7} and Sm{sub 2}O{sub 3} (sintered CaF{sub 2}:Tb,Sm) that were 5 mm in diameter and 1 mm thick, and placed them inside glass cases that had a 7-mm external diameter, 3-mm height, and 1-mm thickness of glass made of synthetic silica with {>=}90% UV transmittance. These glass cases were fixed in dental mouthpieces in a position corresponding to the central maxillary incisors. These mouthpieces were worn by 11 subjects and UV measurements were carried out over a 24-h period in a uniform environment. The results of these TL measurements showed a TL glow peak in the region of 430 K. This was the same as that seen with irradiation from a xenon lamp as basic illumination. The daily UV radiant energy was 72.2 mJ/cm{sup 2} (32.7-143.8 mJ/cm{sup 2}), calculated from the relationship between TL intensity and UV radiant energy. This corresponded to 0.02% of the UV radiant energy contained in the light irradiation specified by ISO 4049.

  17. Intimate Coupling of Photocatalysis and Biodegradation for Degrading Phenol Using Different Light Types: Visible Light vs UV Light.

    Science.gov (United States)

    Zhou, Dandan; Xu, Zhengxue; Dong, Shanshan; Huo, Mingxin; Dong, Shuangshi; Tian, Xiadi; Cui, Bin; Xiong, Houfeng; Li, Tingting; Ma, Dongmei

    2015-07-07

    Intimate coupling of photocatalysis and biodegradation (ICPB) technology is attractive for phenolic wastewater treatment, but has only been investigated using UV light (called UPCB). We examined the intimate coupling of visible-light-induced photocatalysis and biodegradation (VPCB) for the first time. Our catalyst was prepared doping both of Er(3+) and YAlO3 into TiO2 which were supported on macroporous carriers. The macroporous carriers was used to support for the biofilms as well. 99.8% removal efficiency of phenol was achieved in the VPCB, and this was 32.6% higher than that in the UPCB. Mineralization capability of UPCB was even worse, due to less adsorbable intermediates and cell lysis induced soluble microbial products release. The lower phenol degradation in the UPCB was due to the serious detachment of the biofilms, and then the microbes responsible for phenol degradation were insufficient due to disinfection by UV irradiation. In contrast, microbial communities in the carriers were well protected under visible light irradiation and extracellular polymeric substances secretion was enhanced. Thus, we found that the photocatalytic reaction and biodegradation were intimately coupled in the VPCB, resulting in 64.0% removal of dissolved organic carbon. Therefore, we found visible light has some advantages over UV light in the ICPB technology.

  18. Workers' dermal exposure to UV-curable acrylates in the furniture and Parquet industry.

    Science.gov (United States)

    Surakka, J; Lindh, T; Rosén, G; Fischer, T

    2000-12-01

    The use of ultraviolet radiation-curable coatings (UV-coatings) has increased rapidly in the parquet and furniture industry. Work with UV-coatings involves risk from skin exposure to chemically reactive, concentrated acrylates that are known skin contact irritants and sensitizers. Yet, the methods and tools for measuring and quantifying dermal exposure from hazardous chemicals directly on the skin are limited and methods to measure skin exposure to UV-coatings in occupational or environmental settings have been lacking. Skin exposure to UV-coatings was measured employing a quantitative tape stripping method that we have developed for this purpose. A pilot study was performed at three workplaces. In the main study, workers' skin exposure to uncured UV-coatings was measured at seven workplaces and on two separate workdays (rounds 1 and 2) within a six-month period to determine exposure variation. Skin exposure was measured at four standardized sites on the hand, 3-4 times per work shift. The forehead was sampled once. A questionnaire was carried out with the workers in both rounds to find out factors that can affect skin exposure to UV-coatings. The pilot study indicated that both skin and surface contamination to TPGDA-containing UV-coatings were common and varied up to 2110 microgram on the sampling area of 10cm(2). In the main study skin contamination due to TPGDA was found on 16 of 23 workers, at 6 out of the 7 workplaces, and from 36 (5. 4%) of the 664 samples. In round one 8.6% (n=383) of the samples contained TPGDA and in round two 1.1 % (n=281). The average TPGDA mass on all the positive samples (n=36) was 30.4+/-77.0 microgram for the first and second rounds alone this mass was 30.6+/-80 (n=33) and 28.3+/-16.5 microgram (n=3), respectively. Despite the limited sampling area and sampling sites, we could find residues of TPGDA at all sampling times, even at the beginning of the work shift. This may be due to transfer of UV-coatings through contaminated

  19. Tritium decontamination of TFTR carbon tiles employing ultra violet light

    International Nuclear Information System (INIS)

    Shu, W.M.; Ohira, S.; Gentile, C.A.; Oya, Y.; Nakamura, H.; Hayashi, T.; Iwai, Y.; Kawamura, Y.; Konishi, S.; Nishi, M.F.; Young, K.M.

    2001-01-01

    Tritium decontamination on the surface of Tokamak Fusion Test Reactor (TFTR) bumper limiter tiles used during the Deuterium-Deuterium (D-D) phase of TFTR operations was investigated employing an ultra violet light source with a mean wavelength of 172 nm and a maximum radiant intensity of 50 mW/cm 2 . The partial pressures of H 2 , HD, C and CO 2 during the UV exposure were enhanced more than twice, compared to the partial pressures before UV exposure. In comparison, the amount of O 2 decreased during the UV exposure and the production of a small amount of O 3 was observed when the UV light was turned on. Unlike the decontamination method of baking in air or oxygen, the UV exposure removed hydrogen isotopes from the tile to vacuum predominantly in forms of gases of hydrogen isotopes. The tritium surface contamination on the tile in the area exposed to the UV light was reduced after the UV exposure. The results show that the UV light with a wavelength of 172 nm can remove hydrogen isotopes from carbon-based tiles at the very surface

  20. Photochemical decomposition of perfluorooctanoic acid in aqueous periodate with VUV and UV light irradiation

    International Nuclear Information System (INIS)

    Cao, M.H.; Wang, B.B.; Yu, H.S.; Wang, L.L.; Yuan, S.H.; Chen, J.

    2010-01-01

    The photochemical decomposition of perfluorooctanoic acid (PFOA) in aqueous periodate (IO 4 - ) was investigated under two types of low-pressure mercury lamps: one emits at 254 nm light (UV light) and the other emits both 254 nm and 185 nm light (VUV light). PFOA decomposed efficiently under VUV light irradiation while it decomposed poorly under UV light irradiation. The addition of IO 4 - significantly increased the rate of decomposition and defluorination of PFOA irradiated with UV light whereas it decreased both processes under VUV irradiation. Reactive radical (IO 3 ·) generated by photolysis of IO 4 - initiated the oxidation of PFOA in UV process. Aquated electrons (e aq - ), generated from water homolysis, scavenged IO 4 - resulting in decrease of reactive radical species production and PFOA decomposition. The shorter-chain perfluorocarboxylic acids (PFCAs) formed in a stepwise manner from long-chain PFCAs.

  1. Investigation of the effect of UV-LED exposure conditions on the production of vitamin D in pig skin

    DEFF Research Database (Denmark)

    Barnkob, Line Lundbæk; Argyraki, Aikaterini; Petersen, Paul Michael

    2016-01-01

    study the exposure conditions with ultraviolet (UV) LEDs were systematically investigated in the wavelength range 280-340 nm for achieving optimal vitamin D bio-fortification in pig skin. A wavelength of 296 nm was found to be optimal for vitamin D3 production. The maximum dose of 20 kJ/m2 produced 3.......5-4 µg vitamin D3/cm2 pig skin. Vitamin D3 produced was independent on the combination of time and intensity of the LED source. The increased UV exposure by UV-LEDs may be readily implemented in existing food production facilities, without major modifications to the process or processing equipment......The dietary intake of vitamin D is currently below the recommended intake of 10-20 µg vitamin D/day. Foods with increased content of vitamin D or new products with enhanced vitamin D are warranted. Light-emitting diodes (LEDs) are a potential new resource in food production lines. In the present...

  2. Assessing the use of Low Voltage UV-light Emitting Miniature LEDs for Marine Biofouling Control

    Science.gov (United States)

    2016-07-01

    of that required to drive traditional UV mercury lamps . Secondly, given their small size and relatively low cost, UV LEDs provide ease of maintenance...UNCLASSIFIED UNCLASSIFIED Assessing the use of Low Voltage UV -light Emitting Miniature LEDs for Marine Biofouling Control Richard...settling organisms. The introduction of miniature UV light emitting diodes ( LEDs ) as a light source enables them to be embedded into thin, flexible

  3. Influence of UV-A or UV-B light and of the nitrogen source on the induction of ferredoxin-dependent glutamate synthase in etiolated tomato cotyledons

    International Nuclear Information System (INIS)

    Migge, A.; Carrayol, E.; Hirel, B.; Lohmann, M.; Meya, G.; Becker, T.W.

    1998-01-01

    The influence of ultraviolet A (UV-A) or B (UV-B) light and of the nitrogen source on the induction of ferredoxin-dependent glutamate synthase (Fd-GOGAT, EC 1.4.7.1) was examined in etiolated cotyledons of tomato (Lycopersicon escu- lentum L.). The Fd-GOGAT activity increased upon illumination of etiolated tomato cotyledons with UV-A or UV-B light. This stimulation of Fd-GOGAT activity was correlated with an increase in both the Fd-GOGAT transcript level and the Fd-GOGAT protein abundance. These results suggest that UV-A or UV-B light stimulates the de novo synthesis of Fd-GOGAT in etiolated tomato cotyledons. Both UV-A and UV-B light failed to influence the activity of NADH-GOGAT (EC 1.4.1.14) in etiolated tomato cotyledons. Taken together, our data indicate that the tomato genes encoding Fd- or NADH-dependent glutamate synthase are regulated differently by UV-A or UV-B light. No difference with respect to both the Fd-GOGAT transcript and protein abundance was found between cotyledons of tomato seedlings grown with either nitrate or ammonium as the sole N-source in the dark or in white light. In addition, the increase in the Fd-GOGAT protein pool induced by white light in etiolated nitrate-grown tomato seedling cotyledons was similar to that induced by white light in etiolated ammonium-grown tomato seedling cotyledons. These results show that the tomato Fd-GOGAT protein level does not depend strongly on the nature of the nitrogen source and that there appears to be no major stimulatory effect on the Fd-GOGAT protein pool produced by nitrate during the illumination of etiolated tomato cotyledons

  4. UV light blocks EGFR signalling in human cancer cell lines

    DEFF Research Database (Denmark)

    Olsen, BB; Neves-Petersen, M T; Klitgaard, S

    2007-01-01

    UV light excites aromatic residues, causing these to disrupt nearby disulphide bridges. The EGF receptor is rich in aromatic residues near the disulphide bridges. Herein we show that laser-pulsed UV illumination of two different skin-derived cancer cell lines i.e. Cal-39 and A431, which both...... antibodies. There was a threshold level, below which the receptor could not be blocked. In addition, illumination caused the cells to upregulate the cyclin-dependent kinase inhibitor p21WAF1, irrespective of the p53 status. Since the EGF receptor is often overexpressed in cancers and other proliferative skin...... disorders, it might be possible to significantly reduce the proliferative potential of these cells making them good targets for laser-pulsed UV light treatment....

  5. Exposure to UV filters during summer and winter in Danish kindergarten children

    DEFF Research Database (Denmark)

    Krause, Marianna; Andersson, Anna-Maria; Skakkebaek, Niels E

    2017-01-01

    for children during outdoor activities. However, exposure to UV filters all year round together with large inter-individual variation indicate that children's exposure to UV filters also comes from other consumer items, presumably highly influenced by the general lifestyle of an individual child......: this is completely unintended, without benefit, and potentially harmful....

  6. Dependence of UV effect on quality of light during raising of seedlings (Lactuca sativa L.)

    International Nuclear Information System (INIS)

    Bogenrieder, A.; Klein, R.

    1978-01-01

    Greenhouse seedlings of Lactuca sativa L. show a decreased rate of photosynthesis under normal outdoor light conditions due to the effect of UV-light. In this study, the relationship between the declining rate of photosynthesis and the amount of UV in the spectrum was investigated. The determination was made in climatized gas exchange chambers under Xenon arc lamps (XBO 2500 W, Osram). The amount of UV in the spectrum was varied by the use of different surface mirrors made by aluminium evaporation. A linear relationship between the amount of UV-light in the spectrum and the rate of decrease of photosynthesis was obtained with 12 hour radiation. The decrease in photosynthesis is less when the plants are raised under UV-light lamps. (orig.) [de

  7. Exposure to Non-Extreme Solar UV Daylight: Spectral Characterization, Effects on Skin and Photoprotection

    Directory of Open Access Journals (Sweden)

    Claire Marionnet

    2014-12-01

    Full Text Available The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV rays (UVA, 320–400 nm and UVB, 280–320 nm. The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1 the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2 description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3 analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

  8. Exposure to non-extreme solar UV daylight: spectral characterization, effects on skin and photoprotection.

    Science.gov (United States)

    Marionnet, Claire; Tricaud, Caroline; Bernerd, Françoise

    2014-12-23

    The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

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

    Science.gov (United States)

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

    2015-05-01

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

  11. UV-Induced Cell Death in Plants

    Science.gov (United States)

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

    2013-01-01

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

  12. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan. A study in mice

    Directory of Open Access Journals (Sweden)

    Vibenholt Anni

    2010-06-01

    Full Text Available Abstract Background Engineered nanoparticles are smaller than 100 nm and designed to improve or achieve new physico-chemical properties. Consequently, also toxicological properties may change compared to the parent compound. We examined developmental and neurobehavioral effects following maternal exposure to a nanoparticulate UV-filter (UV-titan L181. Methods Time-mated mice (C57BL/6BomTac were exposed by inhalation 1h/day to 42 mg/m3 aerosolized powder (1.7·106 n/cm3; peak-size: 97 nm on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Results Particles consisted of mainly elongated rutile titanium dioxide (TiO2 with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated with polyalcohols. In exposed adult mice, 38 mg Ti/kg was detected in the lungs on day 5 and differential cell counts of bronchoalveolar lavage fluid revealed lung inflammation 5 and 26-27 days following exposure termination, relative to control mice. As young adults, prenatally exposed offspring tended to avoid the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test. Conclusion Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally exposed offspring displayed moderate neurobehavioral alterations. The results are discussed in the light of the observed particle size distribution in the exposure atmosphere and the potential pathways by which nanoparticles may impart changes in fetal development.

  13. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan). A study in mice.

    Science.gov (United States)

    Hougaard, Karin S; Jackson, Petra; Jensen, Keld A; Sloth, Jens J; Löschner, Katrin; Larsen, Erik H; Birkedal, Renie K; Vibenholt, Anni; Boisen, Anne-Mette Z; Wallin, Håkan; Vogel, Ulla

    2010-06-14

    Engineered nanoparticles are smaller than 100 nm and designed to improve or achieve new physico-chemical properties. Consequently, also toxicological properties may change compared to the parent compound. We examined developmental and neurobehavioral effects following maternal exposure to a nanoparticulate UV-filter (UV-titan L181). Time-mated mice (C57BL/6BomTac) were exposed by inhalation 1h/day to 42 mg/m(3) aerosolized powder (1.7.10(6) n/cm(3); peak-size: 97 nm) on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Particles consisted of mainly elongated rutile titanium dioxide (TiO2) with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated with polyalcohols. In exposed adult mice, 38 mg Ti/kg was detected in the lungs on day 5 and differential cell counts of bronchoalveolar lavage fluid revealed lung inflammation 5 and 26-27 days following exposure termination, relative to control mice. As young adults, prenatally exposed offspring tended to avoid the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test). Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally exposed offspring displayed moderate neurobehavioral alterations. The results are discussed in the light of the observed particle size distribution in the exposure atmosphere and the potential pathways by which nanoparticles may impart changes in fetal development.

  14. Stabilization of N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine thin film morphology with UV light

    Energy Technology Data Exchange (ETDEWEB)

    Tomović, A.Ž.; Markešević, N. [Institute of Physics, University of Belgrade, Pregrevica 118, 11000 Belgrade (Serbia); Scarpellini, M.; Bovio, S. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy); Lucenti, E. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy); Institute of Molecular Science and Technology of CNR, via Golgi 19, 20133 Milan (Italy); Milani, P. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy); Zikic, R. [Institute of Physics, University of Belgrade, Pregrevica 118, 11000 Belgrade (Serbia); Jovanović, V.P., E-mail: vladimir.jovanovic@ipb.ac.rs [Institute of Physics, University of Belgrade, Pregrevica 118, 11000 Belgrade (Serbia); Srdanov, V.I. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy)

    2014-07-01

    Owing to their low glass transition temperature, T{sub g}, amorphous thin films of N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (TPD) undergo morphological changes even at room temperature. It has been noticed previously that exposure to UV light can increase apparent T{sub g} of TPD films and thus stabilize their morphology. However, the reason behind increase in structural stability was not examined at the time. Here we present evidence that TPD molecules undergo photo-oxidation in air when exposed to λ ≈ 350 nm radiation and that less than 5% of the photo-oxidized species are needed to prevent dewetting of thin TPD films. We propose that photo-oxidized TPD species bind strongly to both ordinary TPD molecules and to terminal hydroxyl groups at the substrate surface, which decreases mobility of TPD molecules and makes thin TPD film less prone to morphology changes. - Highlights: • We made variable thickness TPD films and exposed them to UV light under ambient conditions. • Mass spectroscopy and proton NMR measurements of irradiated and pristine TPD films • TPD molecules undergo oxidation process under UV light irradiation. • Dipole–dipole interactions may be responsible for stabilization of morphological changes.

  15. UV and air stability of high-efficiency photoluminescent silicon nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jihua, E-mail: yangj@umn.edu [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Liptak, Richard [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Ave, Terre Haute, IN 47803 (United States); Rowe, David; Wu, Jeslin [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Casey, James; Witker, David [Dow Corning Corporation, 2200 W. Salzburg Road, Midland, MI 48686 (United States); Campbell, Stephen A. [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Kortshagen, Uwe, E-mail: kortshagen@umn.edu [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States)

    2014-12-30

    The effects of UV light and air exposure on the photoluminescent properties of nonthermal plasma-synthesized silicon nanocrystals (Si NCs) were investigated. Si NCs with high-efficiency photoluminescence (PL) have been achieved via a post-synthesis hydrosilylation process. Photobleaching is observed within the first few hours of ultra-violet (UV) irradiation. Equilibrium is reached after ∼4 h of UV exposure wherein the Si NCs are able to retain 52% of the initially measured PL quantum yield (PLQY). UV-treated Si NCs showed recovery of PL with time. Gas-phase passivation of Si NCs by hydrogen afterglow injection improves PLQY and PL stability against UV and air exposure. Additionally, phosphorous doping can also improve UV stability of photoluminescent Si NCs.

  16. Thermoluminescent properties of ZrO{sub 2}:Mn for UV light dosimetry; Propiedades termoluminiscentes de ZrO{sub 2}:Mn para dosimetria de la luz UV

    Energy Technology Data Exchange (ETDEWEB)

    Rivera M, T. [Universidad Autonoma Metropolitana Iztapalapa, Deparatmento de Fisica, 09340 Mexico D.F. (Mexico); Azorin N, J. [CICATA-IPN, 11500 Mexico D.F. (Mexico); Falcony G, C. [CINVESTAV-IPN, Departamento de Fisica, 07300 Mexico D.F. (Mexico); Martinez, E.; Garcia, M. [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, 04510 Mexico D.F. (Mexico)

    1999-07-01

    The main source of ultraviolet light (UV) to whom is exposed the population is the one coming from the Sun, although exist some artificial sources too. The UV light can be classified in UV A (315-400)nm, in UV B (180-315) nm and UV C (100-180) nm. In this work are presented the results studying in the thermoluminescent characteristics of ZrO{sub 2}: Mn for the UV dosimetry. The studied dosimetric characteristics were: concentration effect of the doping material, erased thermal treatment, posterior thermal treatment to the irradiation, Tl curve, response in function to the wavelength, response in function to the dose and reproducibility. Finally, presenting results highly promisers for the UV light dosimetry. (Author)

  17. EPR persistence measurements of UV-induced melanin free radicals in whole skin

    International Nuclear Information System (INIS)

    Collins, B.; Poehler, T.O.; Bryden, W.A.

    1995-01-01

    Electron paramagnetic resonance is used to detect the formation of free radicals caused by exposure to ultraviolet radiation in chemically untreated rabbit skin. A fast jump in EPR signal level, occurring over a few seconds, is observed immediately after a skin sample is exposed to UV. This is followed by a slower increase toward an elevated steady-state signal over a period of hours as the skin is continuously exposed to a UV light source. Upon cessation of UV light exposure, EPR signal levels undergo an abrupt drop followed by a slower decay toward natural levels. Elevated free radical concentrations following UV exposure are found to persist for several hours in whole skin. These results are consistent with time resolved EPR measurements of photoinduced radicals in various natural melanins. (Author)

  18. Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression

    Directory of Open Access Journals (Sweden)

    Hidemasa Torii

    2017-02-01

    Full Text Available Prevalence of myopia is increasing worldwide. Outdoor activity is one of the most important environmental factors for myopia control. Here we show that violet light (VL, 360–400 nm wavelength suppresses myopia progression. First, we confirmed that VL suppressed the axial length (AL elongation in the chick myopia model. Expression microarray analyses revealed that myopia suppressive gene EGR1 was upregulated by VL exposure. VL exposure induced significantly higher upregulation of EGR1 in chick chorioretinal tissues than blue light under the same conditions. Next, we conducted clinical research retrospectively to compare the AL elongation among myopic children who wore eyeglasses (VL blocked and two types of contact lenses (partially VL blocked and VL transmitting. The data showed the VL transmitting contact lenses suppressed myopia progression most. These results suggest that VL is one of the important outdoor environmental factors for myopia control. Since VL is apt to be excluded from our modern society due to the excessive UV protection, VL exposure can be a preventive strategy against myopia progression.

  19. Organic UV filters exposure induces the production of inflammatory cytokines in human macrophages.

    Science.gov (United States)

    Ao, Junjie; Yuan, Tao; Gao, Li; Yu, Xiaodan; Zhao, Xiaodong; Tian, Ying; Ding, Wenjin; Ma, Yuning; Shen, Zhemin

    2018-09-01

    Organic ultraviolet (UV) filters, found in many personal care products, are considered emerging contaminants due to growing concerns about potential long-term deleterious effects. We investigated the immunomodulatory effects of four commonly used organic UV filters (2-hydroxy-4-methoxybenzophenone, BP-3; 4-methylbenzylidene camphor, 4-MBC; 2-ethylhexyl 4-methoxycinnamate, EHMC; and butyl-methoxydibenzoylmethane, BDM) on human macrophages. Our results indicated that exposure to these four UV filters significantly increased the production of various inflammatory cytokines in macrophages, particular tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). After exposure to the UV filters, a significant 1.1-1.5 fold increase were found in TNF-α and IL-6 mRNA expression. In addition, both the p38 MAPK and the NF-κB signaling pathways were enhanced 2 to 10 times in terms of phosphorylation after exposure to the UV filters, suggesting that these pathways are involved in the release of TNF-α and IL-6. Molecular docking analysis predicted that all four UV filter molecules would efficiently bind transforming growth factor beta-activated kinase 1 (TAK1), which is responsible for the activation of the p38 MAPK and NF-κB pathways. Our results therefore demonstrate that exposure to the four organic UV filters investigated may alter human immune system function. It provides new clue for the development of asthma or allergic diseases in terms of the environmental pollutants. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Effects of ultraviolet light irradiation on several isozymes in Helicoverpa armigera adults

    International Nuclear Information System (INIS)

    Meng Jianyu; Zhang Changyu; Lei Chaoliang

    2012-01-01

    The effects of ultraviolet (UV)light stress on esterase, peroxidases (POX ), and catalase (CAT) isozymes in Helicoverpa armigera (Hiiber) adults were studied by isozyme eleetrophoresis. When exposed to UV light irradiation, zymogram of esterase isozyme changed mainly in number and activity of isozyme. After 30 min and 60 min exposure, the intensity of isozyme bands E4, E9 and El0 were enhanced, E2 and E8 were weakened. The bands E1, E5, E7 and Ell disappeared after UV light irradiation, while E3 and E6 newly emerged. At the longest exposure time (90 min), the intensity of isozyme bands E4 and E9 was enhanced, while the intensity of E2 and E8 was weakened. The bands E1, E5 and E7 disappeared after UV light irradiation, whereas E3 and E6 newly emerged. The intensity of POX band P5 was enhanced in adults following the exposure to UV light for 30, 60, 90 minutes. The intensity of CAT band C1 was enhanced in adults following the exposure to UV light for 30, 60, 90 minutes, but that of band C2 was weakened after 30 min and 90 min exposure in comparison with the control

  1. Characterization and optimization of an inkjet-printed smart textile UV-sensor cured with UV-LED light

    Science.gov (United States)

    Seipel, S.; Yu, J.; Periyasamy, A. P.; Viková, M.; Vik, M.; Nierstrasz, V. A.

    2017-10-01

    For the development of niche products like smart textiles and other functional high-end products, resource-saving production processes are needed. Niche products only require small batches, which makes their production with traditional textile production techniques time-consuming and costly. To achieve a profitable production, as well as to further foster innovation, flexible and integrated production techniques are a requirement. Both digital inkjet printing and UV-light curing contribute to a flexible, resource-efficient, energy-saving and therewith economic production of smart textiles. In this article, a smart textile UV-sensor is printed using a piezoelectric drop-on-demand printhead and cured with a UV-LED lamp. The UVcurable ink system is based on free radical polymerization and the integrated UVsensing material is a photochromic dye, Reversacol Ruby Red. The combination of two photoactive compounds, for which UV-light is both the curer and the activator, challenges two processes: polymer crosslinking of the resin and color performance of the photochromic dye. Differential scanning calorimetry (DSC) is used to characterize the curing efficiency of the prints. Color measurements are made to determine the influence of degree of polymer crosslinking on the developed color intensities, as well as coloration and decoloration rates of the photochromic prints. Optimized functionality of the textile UV-sensor is found using different belt speeds and lamp intensities during the curing process.

  2. Ultraviolet light and cutaneous lupus

    NARCIS (Netherlands)

    Bijl, Marc; Kallenberg, Cees G. M.

    2006-01-01

    Exposure to ultraviolet (UV) light is one of the major factors known to trigger cutaneous disease activity in (systemic) lupus erythematosus patients. UV light, UVB in particular, is a potent inducer of apoptosis. Currently, disturbed clearance of apoptotic cells is one of the concepts explaining

  3. The effect of UV-light on DNA metabolism of lymphocytes during radiotherapy

    International Nuclear Information System (INIS)

    Klein, W.; Altmann, H.; Klein, H.; Alth, G.; Koren, H.

    1980-02-01

    The effects of gamma plus electron therapy and only gammatherapy, respectively, were investigated in lymphocytes of the peripheral blood of 10 patients with malignancies. The efficiency of DNA repair was tested by an irradiation of the cells with UV light beside radiotherapy. Using only gamma rays for therapy, the effects by UV light were not so pronounced than for using gamma plus electron therapy. (author)

  4. The study of temperature and UV light effect in anthocyanin extract from dragon fruit (Hylocereus costaricensis) rind using UV-Visible spectrophotometer

    Science.gov (United States)

    Purbaningtias, Tri Esti; Aprilia, Anisa Cahyani; Fauzi'ah, Lina

    2017-12-01

    This study aimed to determine the total of anthocyanin content in ethanol extract from super red dragon fruit rind. The extraction was affected by temperature and light conditions. The determination of anthocyanin's total content was performed with a variation of pH and analyzed by UV-Visible spectrophotometer. The results showed that the average contained total anthocyanins obtained at room temperature, 40 and 60 °C were 4.6757, 5.6108, 21.9757 mg/L, respectively. In higher temperatures, it was observed the more anthocyanin extracted. The concentration of anthocyanin extract without UV light was 2.5716 mg/L, it was less than UV light assisted extract, i.e. 5.3770 mg / L.

  5. Evidence for some signal transduction elements involved in UV-light-dependent responses in parsley protoplasts

    International Nuclear Information System (INIS)

    Frohnmeyer, H.; Bowler, C.; Schäfer, E.

    1997-01-01

    The signalling pathways used by UV-light are largely unknown. Using protoplasts from a heterotrophic parsley (Petroselinum crispum L.) cell culture that exclusively respond to UV-B light between 300 and 350 nm with a fast induction of genes encoding flavonoid biosynthetic enzymes, information was obtained about the UV-light signal transduction pathway for chalcone synthase (CHS) and phenylalanine ammonia-lyase (PAL) gene expression. Pharmacological effectors which influence intracellular calcium levels, calmodulin and the activity of serine/threonine kinases also changed the UV-light-dependent expression of these genes. This evaluation indicated the participation of these components on the UV-B-mediated signal transduction cascade to CHS. In contrast, neither membrane-permeable cyclic GMP nor the tyrosine kinase inhibitor genistein affected CHS or PAL expression. Similar results were obtained in protoplasts, which have been transiently transformed with CHS-promoter/GUS (β-glucuronidase) reporter fusion constructs. The involvement of calcium and calmodulin was further indicated in a cell-free light-responsive in vitro transcription system from evacuolated parsley protoplasts. In conclusion, there is evidence now that components of the UV-light-dependent pathway leading to the CHS-promoter are different from the previously characterized cGMP-dependent pathway to CHS utilized by phytochrome in soybean (Glycine max) and tomato seedlings (Lycopersicon esculentum). (author)

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  7. Solar UV exposure among outdoor workers in Denmark measured with personal UV-B dosimeters: technical and practical feasibility.

    Science.gov (United States)

    Grandahl, Kasper; Mortensen, Ole Steen; Sherman, David Zim; Køster, Brian; Lund, Paul-Anker; Ibler, Kristina Sophie; Eriksen, Paul

    2017-10-10

    Exposure to solar ultraviolet radiation is a well-known cause of skin cancer. This is problematic for outdoor workers. In Denmark alone, occupational skin cancer poses a significant health and safety risk for around 400,000 outdoor workers. Objective measures of solar ultraviolet radiation exposure are needed to help resolve this problem. This can be done using personal ultraviolet radiation dosimeters. We consider technical and practical feasibility of measuring individual solar ultraviolet exposure at work and leisure in professions with different á priori temporal high-level outdoor worktime, using aluminium gallium nitride (AlGaN) photodiode detector based personal UV-B dosimeters. Essential technical specifications including the spectral and angular responsivity of the dosimeters are described and pre-campaign dosimeter calibration applicability is verified. The scale and conduct of dosimeter deployment and campaign in-field measurements including failures and shortcomings affecting overall data collection are presented. Nationwide measurements for more than three hundred and fifty workers from several different professions were collected in the summer of 2016. On average, each worker's exposure was measured for a 2-week period, which included both work and leisure. Data samples of exposure at work during a Midsummer day show differences across professions. A construction worker received high-level occupational UV exposure most of the working day, except during lunch hour, accumulating to 5.1 SED. A postal service worker was exposed intermittently around noon and in the afternoon, preceded by no exposure forenoon when packing mail, accumulating to 1.6 SED. A crane fitter was exposed only during lunch hour, accumulating to 0.7 SED. These findings are in line with our specialist knowledge as occupational physicians. Large-scale use of personal UV-B dosimeters for measurement of solar ultraviolet radiation exposure at work and leisure in Denmark is indeed

  8. Photocatalytic activity of Fe-doped CaTiO₃ under UV-visible light.

    Science.gov (United States)

    Yang, He; Han, Chong; Xue, Xiangxin

    2014-07-01

    The photocatalytic degradation of methylene blue (MB) over Fe-doped CaTiO₃ under UV-visible light was investigated. The as-prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) system, Fourier transform infrared spectra (FT-IR), and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the doping with Fe significantly promoted the light absorption ability of CaTiO₃ in the visible light region. The Fe-doped CaTiO₃ exhibited higher photocatalytic activity than CaTiO₃ for the degradation of MB. However, the photocatalytic activity of the Fe-doped CaTiO₃ was greatly influenced by the calcination temperature during the preparation process. The Fe-doped CaTiO₃ prepared at 500°C exhibited the best photocatalytic activity, with degradation of almost 100% MB (10ppm) under UV-visible light for 180 min. Copyright © 2014. Published by Elsevier B.V.

  9. Empirical Modeling of Physiochemical Immune Response of Multilayer Zinc Oxide Nanomaterials under UV Exposure to Melanoma and Foreskin Fibroblasts

    Science.gov (United States)

    Fakhar-E-Alam, Muhammad; Akram, M. Waseem; Iqbal, Seemab; Alimgeer, K. S.; Atif, M.; Sultana, K.; Willander, M.; Wang, Zhiming M.

    2017-04-01

    Carcinogenesis is a complex molecular process starting with genetic and epigenetic alterations, mutation stimulation, and DNA modification, which leads to proteomic adaptation ending with an uncontrolled proliferation mechanism. The current research focused on the empirical modelling of the physiological response of human melanoma cells (FM55P) and human foreskin fibroblasts cells (AG01518) to the multilayer zinc oxide (ZnO) nanomaterials under UV-A exposure. To validate this experimental scheme, multilayer ZnO nanomaterials were grown on a femtotip silver capillary and conjugated with protoporphyrin IX (PpIX). Furthermore, PpIX-conjugated ZnO nanomaterials grown on the probe were inserted into human melanoma (FM55P) and foreskin fibroblasts cells (AG01518) under UV-A light exposure. Interestingly, significant cell necrosis was observed because of a loss in mitochondrial membrane potential just after insertion of the femtotip tool. Intense reactive oxygen species (ROS) fluorescence was observed after exposure to the ZnO NWs conjugated with PpIX femtotip model under UV exposure. Results were verified by applying several experimental techniques, e.g., ROS detection, MTT assay, and fluorescence spectroscopy. The present work reports experimental modelling of cell necrosis in normal human skin as well as a cancerous tissue. These obtained results pave the way for a more rational strategy for biomedical and clinical applications.

  10. Encapsulation of ethylhexyl methoxycinnamate, a light-sensitive UV filter, in lipid nanoparticles.

    Science.gov (United States)

    Durand, L; Habran, N; Henschel, V; Amighi, K

    2010-01-01

    The aim of this study was to encapsulate ethylhexyl methoxycinnamate (EMC), a commonly used UVB filter, in a solid lipid matrix in order to obtain microparticles and then nanoparticles to reduce its photo-instability under UV light exposure. Glyceryl behenate, rice bran wax and ozokerite were investigated for encapsulating EMC. The suspensions of nanoparticles contained 70% encapsulated EMC (relative to the lipid mass). The absorbance level at 310 nm of suspensions containing nanoparticles was more than twice that of those containing microparticles. So, decreasing the size of particles improved the efficiency of light protection, regardless of the lipid material used. Moreover, free EMC presented a 30% loss of its efficiency after 2 h of irradiation, whereas the three NLC formulations showed a loss of absorbency between 10% and 21%. The in vitro cutaneous penetration test did not show a higher potential penetration for EMC contained in nanosuspensions compared to free EMC.

  11. Degradation of photovoltaic backsheet materials under multi-factor accelerated UV light exposures

    Science.gov (United States)

    Klinke, Addison G.; Gok, Abdulkerim; Ifeanyi, Silas I.; French, Roger H.; Bruckman, Laura S.

    2017-08-01

    Long term outdoor durability of photovoltaic (PV) module backsheets is critical to a module's power output over its lifetime. The use of uoropolymer-based backsheets or the addition of stabilizers to polyethylene-terephthalate (PET) and polyamide (PA) type backsheets can help extend their lifetime. This study presents the performance of 21 backsheets made of 8 different material combinations under ASTM G154 Cycle 4 accelerated light exposures. The backsheets were subjected to 4000 hours of high irradiance UVA light at a peak intensity of 1.55 W=m2 at 340 nm at 70°C with and without a condensing humidity cycle at 50°C. Backsheets were evaluated, with repeated measurements, using various evaluation techniques to identify and assess potential signs of degradation. These evaluations included the yellowness index (YI), CIE color space coordinates, and gloss at 20, 60, and 85°. The temporal evolution of the relative color change ΔE was statistically analyzed to develop a stress-response model which used the UVA light dose to predict color change. It was found that the PVF/PET/E backsheet performed the best while PET/PET/E and THV/PET/EVA backsheets performed the worst. Additionally, substantial variation in color change response, attributable to key manufacturing differences, was observed within a given material type.

  12. 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)

    1997-12-31

    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.

  13. 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.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  15. 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.

  16. UV light induced insulator-metal transition in ultra-thin ZnO/TiO{sub x} stacked layer grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Saha, D., E-mail: sahaphys@gmail.com, E-mail: pmisra@rrcat.gov.in; Misra, P., E-mail: sahaphys@gmail.com, E-mail: pmisra@rrcat.gov.in; Joshi, M. P.; Kukreja, L. M. [Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2016-08-28

    In the present study, atomic layer deposition has been used to grow a series of Ti incorporated ZnO thin films by vertically stacking different numbers (n = 1–7) of ZnO/TiO{sub x} layers on (0001) sapphire substrates. The effects of defect states mediated chemisorption of O{sub 2} and/OH groups on the electrical properties of these films have been investigated by illuminating the samples under UV light inside a high vacuum optical cryostat. The ultra-thin film having one stacked layer (n = 1) did not show any change in its electrical resistance upon UV light exposure. On the contrary, marginal drop in the electrical resistivity was measured for the samples with n ≥ 3. Most surprisingly, the sample with n = 2 (thickness ∼ 12 nm) showed an insulator to metal transition upon UV light exposure. The temperature dependent electrical resistivity measurement on the as grown film (n = 2) showed insulating behaviour, i.e., diverging resistivity on extrapolation to T→ 0 K. However, upon UV light exposure, it transformed to a metallic state, i.e., finite resistivity at T → 0 K. Such an insulator-metal transition plausibly arises due to the de-trapping of conduction electrons from the surface defect sites which resulted in an upward shift of the Fermi level above the mobility edge. The low-temperature electron transport properties on the insulating film (n = 2) were investigated by a combined study of zero field electrical resistivity ρ(T) and magnetoresistance (MR) measurements. The observed negative MR was found to be in good agreement with the magnetic field induced suppression of quantum interference between forward-going paths of tunnelling electrons. Both ρ(T) and MR measurements provided strong evidence for the Efros-Shklovskii type variable range hopping conduction in the low-temperature (≤40 K) regime. Such studies on electron transport in ultra-thin n-type doped ZnO films are crucial to achieve optimum functionality

  17. UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report; UV-abhaengige Vitamin D Synthese. Bilanzierung der Expositionszeit durch UV zur Produktion des optimalen Vitamin D{sub 3}-Bedarfes im menschlichen Koerper. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

    2012-10-15

    UV-dependent vitamin D{sub 3} synthesis - balancing of UV exposure time and the production of an optimal vitamin D{sub 3} status in men The adverse health effects on human skin and eyes by UV radiation have been well known for years. They are known to the public, too. Increased exposures by the UV-B fraction of solar radiation cause e.g. sun burn as an acute skin reaction or an increased risk on skin cancer as a chronic effect. Radiation of the same spectral UV-B range is necessary to induce the essential vitamin D metabolism in men. The UV-induced vitamin D synthesis in the skin supplies the body with more than 90 % while our typical nutrition contributes no more than 10 %. These photobiological effects are diametrically opposed. Therefore, up to now there are contradictory recommendations to the public concerning the health effects of solar UV exposure. The aim of this research project was to evaluate the quantitative and qualitative relations of UV exposure and the vitamin D status in men taking into account different conditions in the population. In result, well-balanced recommendations on optimal UV exposures for the different fractions of the population should be elaborated, realizing health protection aspects against detrimental UV effects. A literature survey (updated in 2011) summarizes the current knowledge on the vitamin D metabolism, on the effects of the hormone vitamin D and on the stage of the current discussion on the optimal vitamin D status. In a number of studies of this project the effects of UV exposure on the vitamin D status (25OH-vitamin D{sub 3} und 1,25OH-vitamin D{sub 3}) were investigated. Exposure parameters were the photobiologically effective UV dose (with respect to the minimal erythema dose MED = individual sun burn dose in each investigated volunteer) and the extent of the exposed skin area: face and hands (like everyday conditions) or whole body respectively. Serial UV exposures were applied by natural solar UV radiation or by

  18. Mutation induction in haploid yeast after split-dose radiation exposure. II. Combination of UV-irradiation and X-rays.

    Science.gov (United States)

    Keller, B; Zölzer, F; Kiefer, J

    2004-01-01

    Split-dose protocols can be used to investigate the kinetics of recovery from radiation damage and to elucidate the mechanisms of cell inactivation and mutation induction. In this study, a haploid strain of the yeast, Saccharomyces cerevisiae, wild-type with regard to radiation sensitivity, was irradiated with 254-nm ultraviolet (UV) light and then exposed to X-rays after incubation for 0-6 hr. The cells were incubated either on nutrient medium or salt agar between the treatments. Loss of reproductive ability and mutation to canavanine resistance were measured. When the X-ray exposure immediately followed UV-irradiation, the X-ray survival curves had the same slope irrespective of the pretreatment, while the X-ray mutation induction curves were changed from linear to linear quadratic with increasing UV fluence. Incubations up to about 3 hr on nutrient medium between the treatments led to synergism with respect to cell inactivation and antagonism with respect to mutation, but after 4-6 hr the two treatments acted independently. Incubation on salt agar did not cause any change in the survival curves, but there was a strong suppression of X-ray-induced mutation with increasing UV fluence. On the basis of these results, we suggest that mutation after combined UV and X-ray exposure is affected not only by the induction and suppression of DNA repair processes, but also by radiation-induced modifications of cell-cycle progression and changes in the expression of the mutant phenotype. Copyright 2004 Wiley-Liss, Inc.

  19. Medical UV exposures and HIV activation

    International Nuclear Information System (INIS)

    Zmudzka, B.Z.; Miller, S.A.; Jacobs, M.E.; Beer, J.Z.

    1996-01-01

    This paper presents the first attempt to evaluate the potential of clinical UV exposures to induce the human immunodeficiency (HIV) promoter and, thus, to upregulate HIV growth in those skin cells that are directly affected by the exposure. Using the data for HIV promoter activation in vitro, we computed UVB and psoralen plus UVA (PUVA) doses that produce 50% of the maximal promoter activation (AD 50 ). Then, using (a) literature data for UV transmittance in the human skin, (b) a composite action spectrum for HIV promoter and pyrimidine dimer induction by UVB and (c) an action spectrum for DNA synthesis inhibition by PUVA, we estimated the distribution of medical UVB and PUVA doses in the skin. This allowed us to estimate how deep into the skin the HIV-activating doses might penetrate in an initial and an advanced stge of UVB and PUVA therapy. Such analysis was done for normal type II skin and for single exposures. For UVB we found that, when the incident dose on the surface of the skin is 500 J/m 2 (290-320 nm) (initial stage of the therapy), the dose producing 50% of the maximal HIV promoter activation (AD 50 UVB ) is limited to the stratum corneum. For PUVA we found that, when the incident UVA doses are 25 or 100 kJ/m 2 (320-400 nm) (an initial and an advanced stage of therapy, respectively), and the 8-methoxypsoralen concentration in the blood is 0.1 μg/mL (the desired level), the combined doses to the mid epidermis (and some areas of the upper dermis) are well below the 50% HIV promoter-activating PUVA dose (AD 50 PUVA ). These results suggest that the probability of HIV activation in the epidermis by direct mechanisms is higher for UVB than for PUVA treatment. However, complexities of the UV-inducible HIV activation and immunomodulatory phenomena are such that our results by themselves should not be taken as an indication that UVB therapy carries a high risk than PUVA therapy when administered to HIV-infected patients. (Author)

  20. Does Temperature and UV Exposure History Modulate the Effects of Temperature and UV Stress on Symbiodinium Growth Rates?

    Science.gov (United States)

    Temperature and ultraviolet radiation (UV) alone or in combination are known to inhibit the growth of Symbiodinium isolates. This conclusion was drawn from a number of studies having widely different exposure scenarios. Here we have examined the effects of pre-exposure acclimat...

  1. NIR-Vis-UV Light-Responsive Actuator Films of Polymer-Dispersed Liquid Crystal/Graphene Oxide Nanocomposites.

    Science.gov (United States)

    Cheng, Zhangxiang; Wang, Tianjie; Li, Xiao; Zhang, Yihe; Yu, Haifeng

    2015-12-16

    To take full advantage of sunlight for photomechanical materials, NIR-vis-UV light-responsive actuator films of polymer-dispersed liquid crystal (PDLC)/graphene oxide (GO) nanocomposites were fabricated. The strategy is based on phase transition of LCs from nematic to isotropic phase induced by combination of photochemical and photothermal processes in the PDLC/GO nanocomposites. Upon mechanical stretching of the film, both topological shape change and mesogenic alignment occurred in the separated LC domains, enabling the film to respond to NIR-vis-UV light. The homodispersed GO flakes act as photoabsorbent and nanoscale heat source to transfer NIR or VIS light into thermal energy, heating the film and photothermally inducing phase transition of LC microdomains. By utilizing photochemical phase transition of LCs upon UV-light irradiation, one azobenzene dye was incorporated into the LC domains, endowing the nanocomposite films with UV-responsive property. Moreover, the light-responsive behaviors can be well-controlled by adjusting the elongation ratio upon mechanical treatment. The NIR-vis-UV light-responsive PDLC/GO nanocomposite films exhibit excellent properties of easy fabrication, low-cost, and good film-forming and mechanical features, promising their numerous applications in the field of soft actuators and optomechanical systems driven directly by sunlight.

  2. Exposure to 4100K fluorescent light elicits sex specific transcriptional responses in Xiphophorus maculatus skin.

    Science.gov (United States)

    Boswell, William T; Boswell, Mikki; Walter, Dylan J; Navarro, Kaela L; Chang, Jordan; Lu, Yuan; Savage, Markita G; Shen, Jianjun; Walter, Ronald B

    2018-06-01

    It has been reported that exposure to artificial light may affect oxygen intake, heart rate, absorption of vitamins and minerals, and behavioral responses in humans. We have reported specific gene expression responses in the skin of Xiphophorus fish after exposure to ultraviolet light (UV), as well as, both broad spectrum and narrow waveband visible light. In regard to fluorescent light (FL), we have shown that male X. maculatus exposed to 4100K FL (i.e. "cool white") rapidly suppress transcription of many genes involved with DNA replication and repair, chromosomal segregation, and cell cycle progression in skin. We have also detailed sex specific transcriptional responses of Xiphophorus skin after exposure to UVB. However, investigation of gender differences in global gene expression response after exposure to 4100K FL has not been reported, despite common use of this FL source for residential, commercial, and animal facility illumination. Here, we compare RNA-Seq results analyzed to assess changes in the global transcription profiles of female and male X. maculatus skin in response to 4100K FL exposure. Our results suggest 4100K FL exposure incites a sex-biased genetic response including up-modulation of inflammation in females and down modulation of DNA repair/replication in males. In addition, we identify clusters of genes that become oppositely modulated in males and females after FL exposure that are principally involved in cell death and cell proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. 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)

    Ribeiro, Fabianne; Ferreira, Nuno C.G.; Ferreira, Abel; Soares, Amadeu M.V.M.; Loureiro, Susana

    2011-01-01

    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

  4. p38-MK2 signaling axis regulates RNA metabolism after UV-light-induced DNA damage

    DEFF Research Database (Denmark)

    Borisova, Marina E; Voigt, Andrea; Tollenaere, Maxim A X

    2018-01-01

    quantitative phosphoproteomics and protein kinase inhibition to provide a systems view on protein phosphorylation patterns induced by UV light and uncover the dependencies of phosphorylation events on the canonical DNA damage signaling by ATM/ATR and the p38 MAP kinase pathway. We identify RNA-binding proteins......Ultraviolet (UV) light radiation induces the formation of bulky photoproducts in the DNA that globally affect transcription and splicing. However, the signaling pathways and mechanisms that link UV-light-induced DNA damage to changes in RNA metabolism remain poorly understood. Here we employ...

  5. Ultraviolet radiation levels associated with the use of fluorescent general lighting, UV-A and UV-B lamps in the workplace and home

    CERN Document Server

    Whillock, M; MacKinlay, Alistair F; Mundy, S J; Todd, Carl David

    1988-01-01

    A detailed programme of measurements was undertaken by NRPB to determine the ultraviolet irradiance levels likely to be encountered in the workplace and in the home, where fluorescent lighting is used. Assessments have been made of the possible potential risk of the induction of acute effects (photokeratitis, erythema) and of inducing malignant melanoma and non-malignant melanoma skin cancers resulting from exposure to commonly used fluorescent lamps. The optical absorption properties of materials commonly used in diffusers and controllers in commercial and domestic lighting units were also measured. Irradiance data, both weighted (for biological effectiveness) and unweighted, for various lamp types are presented in the report, together with some typical spectral output distributions. The results show that at commonly used illumination levels the UVR emissions from general and special fluorescent lamps presented neither an acute nor a significant chronic hazard. High UV-B emission levels were measured from 'U...

  6. UV sensitivity of various solid state detectors

    International Nuclear Information System (INIS)

    Knezevic, Zeljka; Ranogajec-Komor, Maria; Miljanic, Saveta

    2008-01-01

    Full text: The light sensitivity is an important characteristic of solid state passive dosimeters used in individual, clinical and environmental dosimetry. Light sensitivity stands for the response directly induced by visible or UV light in a fully annealed material. For the above mentioned applications a negligible light sensitivity is an advantage. However, high light sensitivity and linear response allows the use of detectors as UV dosimeters. For this purpose various TL detectors and the glass element of the RPL dosemeter type SC-1 were systematically investigated after exposure to UV light (254 and 366 nm) as a function of time. The following solid state detectors were investigated relative to TLD-100: Li 2 B 4 O 7 :Cu,Ag,P LiF:Mg,Cu,P, LiF:Mg,Cu,Si, Al 2 O 3 :C and the glass element of RPL dosimeter. UV irradiations were performed with Camag UV lamp at 254 nm and at 366 nm. The illumination times were 5, 10 and 20 minutes. Day light illumination was also carried out at room temperature over time period of several hours up to 2 weeks. The UV light response of each detector was compared to the response obtained after irradiation with 137 Cs. Al 2 O 3 :C, showed high light sensitivity; after 10 minutes illumination with 254 nm UV light the response was equivalent to 130 mGy 137 Cs gamma irradiation. The 254 nm UV response of LiF:Mg,Cu,P (GR-200 A), as well as TLD-700H and Li 2 B 4 O 7 :Cu,Ag,P were proportional to the time of illumination. The responses after 10 min UV illumination were equivalent to 0.001 mGy, 0.01 mGy and 0.1 mGy 137 Cs gamma irradiation, respectively. The complete SC-1 RPL dosimeter is insensitive to light because the glass element is encapsulated in light protected holder throughout the automatic evaluation process following the annealing (irradiation, preheat, readout). The responses of the previously annealed glass element after 20 min illumination with 254 nm and 366 nm UV light were equivalent to 45μSv and 3 μSv of 137 Cs gamma

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

    International Nuclear Information System (INIS)

    Tevini, M.; Steinmüller, D.

    1987-01-01

    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 Cl 3 AcOH resulted in strong inhibition of alkane accumulation, whereas the amount of alkane-1-ols was changed neither at low nor at moderate concentrations of Cl 3 AcOH but their homologue distribution shifted towards longer chain lengths. This shifting was depressed in the presence of UV-B. At high concentrations of Cl 3 Ac0H 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)

  8. Drosophila TRPA1 isoforms detect UV light via photochemical production of H2O2

    Science.gov (United States)

    Guntur, Ananya R.; Gu, Pengyu; Takle, Kendra; Chen, Jingyi; Xiang, Yang; Yang, Chung-Hui

    2015-01-01

    The transient receptor potential A1 (TRPA1) channel is an evolutionarily conserved detector of temperature and irritant chemicals. Here, we show that two specific isoforms of TRPA1 in Drosophila are H2O2 sensitive and that they can detect strong UV light via sensing light-induced production of H2O2. We found that ectopic expression of these H2O2-sensitive Drosophila TRPA1 (dTRPA1) isoforms conferred UV sensitivity to light-insensitive HEK293 cells and Drosophila neurons, whereas expressing the H2O2-insensitive isoform did not. Curiously, when expressed in one specific group of motor neurons in adult flies, the H2O2-sensitive dTRPA1 isoforms were as competent as the blue light-gated channelrhodopsin-2 in triggering motor output in response to light. We found that the corpus cardiacum (CC) cells, a group of neuroendocrine cells that produce the adipokinetic hormone (AKH) in the larval ring gland endogenously express these H2O2-sensitive dTRPA1 isoforms and that they are UV sensitive. Sensitivity of CC cells required dTRPA1 and H2O2 production but not conventional phototransduction molecules. Our results suggest that specific isoforms of dTRPA1 can sense UV light via photochemical production of H2O2. We speculate that UV sensitivity conferred by these isoforms in CC cells may allow young larvae to activate stress response—a function of CC cells—when they encounter strong UV, an aversive stimulus for young larvae. PMID:26443856

  9. The effect of simultaneous exposure of HEMn-DP and HEMn-LP melanocytes to nicotine and UV-radiation on the cell viability and melanogenesis

    International Nuclear Information System (INIS)

    Delijewski, Marcin; Wrześniok, Dorota; Beberok, Artur; Rok, Jakub; Otręba, Michał; Buszman, Ewa

    2016-01-01

    Nicotine is a main compound of tobacco plants and may affect more than a billion people all over the world that are permanently exposed to nicotine from cigarettes, various forms of smoking cessation therapies, electronic cigarettes or second-hand smoke. It is known that nicotine forms complexes with melanin what may lead to accumulation of this alkaloid in tissues of living organisms containing the pigment. This may affect the viability of cells and process of melanin biosynthesis that takes place in melanocytes. Although UV radiation is known to be a particular inductor of melanin biosynthesis, its simultaneous effect with nicotine on this process as well as the viability of human cells containing melanin have not been assessed so far. The aim of this study was to examine the simultaneous impact of nicotine and UV radiation on viability and melanogenesis in cultured normal human melanocytes dark (HEMn-DP) and light (HEMn-LP) pigmented. Nicotine together with UV radiation induced concentration-dependent loss in melanocytes viability. The higher cell loss was observed in dark pigmented melanocytes in comparison to light pigmented cells. Simultaneous exposure of cells to nicotine and UV radiation also caused changes in melanization process in both tested cell lines. The data suggest that simultaneous exposure of melanocytes to nicotine and UV radiation up-regulates melanogenesis and affects cell viability. Observed processes are more pronounced in dark pigmented cells. - Highlights: • Nicotine and UVA induced concentration-dependent loss in melanocytes viability. • Nicotine and UVA modulated melanization process in melanocytes. • Changes in viability and melanization were more pronounced in dark pigmented cells.

  10. The effect of simultaneous exposure of HEMn-DP and HEMn-LP melanocytes to nicotine and UV-radiation on the cell viability and melanogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Delijewski, Marcin; Wrześniok, Dorota; Beberok, Artur; Rok, Jakub; Otręba, Michał; Buszman, Ewa, E-mail: ebuszman@sum.edu.pl

    2016-11-15

    Nicotine is a main compound of tobacco plants and may affect more than a billion people all over the world that are permanently exposed to nicotine from cigarettes, various forms of smoking cessation therapies, electronic cigarettes or second-hand smoke. It is known that nicotine forms complexes with melanin what may lead to accumulation of this alkaloid in tissues of living organisms containing the pigment. This may affect the viability of cells and process of melanin biosynthesis that takes place in melanocytes. Although UV radiation is known to be a particular inductor of melanin biosynthesis, its simultaneous effect with nicotine on this process as well as the viability of human cells containing melanin have not been assessed so far. The aim of this study was to examine the simultaneous impact of nicotine and UV radiation on viability and melanogenesis in cultured normal human melanocytes dark (HEMn-DP) and light (HEMn-LP) pigmented. Nicotine together with UV radiation induced concentration-dependent loss in melanocytes viability. The higher cell loss was observed in dark pigmented melanocytes in comparison to light pigmented cells. Simultaneous exposure of cells to nicotine and UV radiation also caused changes in melanization process in both tested cell lines. The data suggest that simultaneous exposure of melanocytes to nicotine and UV radiation up-regulates melanogenesis and affects cell viability. Observed processes are more pronounced in dark pigmented cells. - Highlights: • Nicotine and UVA induced concentration-dependent loss in melanocytes viability. • Nicotine and UVA modulated melanization process in melanocytes. • Changes in viability and melanization were more pronounced in dark pigmented cells.

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

    International Nuclear Information System (INIS)

    Karentz, D.; Cleaver, J.E.

    1986-01-01

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

  12. Characterization of non-dimer DNA lesions and cellular damages caused by ultraviolet light

    International Nuclear Information System (INIS)

    Nakao, Kumi

    1989-01-01

    To understand the mechanisms of carcinogenicity and cytotoxicity induced by ultraviolet (UV) light, non-dimer DNA damages produced by near UV light (wave-length: 290∼320 nm) were examined by alkaline elution using Chinese hamster V-79 cells. UV exposure produced a dose-dependent induction of DNA single strand breaks and DNA-protein crosslinks. However, neither of these DNA lesions were repaired within a 24 hr incubation of the cells following UV exposure. Rather the number of these lesions increased. Also, UV exposure inhibited DNA and RNA synthesis. In addition, UV induced both cytotoxicity and chromosomal aberration. Electron spin resornance (ESR) studies showed that the exposure of cells to UV light resulted in the appearance of an ESR signal at -120degC. The roles of glutathione, vitamin E and vitamin B 2 , which were celluar antioxidant, on the induction of cytotoxicity by UV exposure were also examined. Pretreatment with vitamin E reduced the cytotoxicty caused by UV, whereas neither preteatment with vitamin B 2 nor the alteration of cellular gluthaione content affected the cytotoxicity. These results suggest that non-dimer DNA damages, such as DNA single strand breaks and DNA-protein crosslinks play an important role in inducing UV-carcinogenicity and UV-cytotoxicity, and that the mechanisms of these damages may be associated with the generation of free radicals. (author)

  13. UV response on dielectric properties of nano nematic liquid crystal

    Directory of Open Access Journals (Sweden)

    Kamal Kumar Pandey

    2018-03-01

    Full Text Available In this work, we investigate the effect of UV light irradiation on the dielectric parameters of nematic liquid crystal (5CB and ZnO nanoparticles dispersed liquid crystal. With addition of nanoparticles in nematic LC are promising new materials for a variety of application in energy harvesting, displays and photonics including the liquid crystal laser. To realize many applications, however we optimize the properties of liquid crystal and understand how the UV light irradiation interact the nanoparticles and LC molecules in dispersed/doped LC. The dielectric permittivity and loss factor have discussed the pure nematic LC and dispersed/doped system after, during and before UV light exposure. The dielectric relaxation spectroscopy was carried out in the frequency range 100 Hz–10 MHz in the nematic mesophase range. Keywords: Dielectric permittivity, Relaxation frequency, Nematic liquid crystal, UV light irradiation

  14. Mechanism of Cuticle Hole Development in Human Hair Due to UV-Radiation Exposure

    Directory of Open Access Journals (Sweden)

    Kazuhisa Maeda

    2018-03-01

    Full Text Available Hair is easily damaged by ultraviolet (UV radiation, bleaching agents or permanent wave treatments, and as damage progresses, hair loses its gloss, develops split ends and breaks. However, the causes of hair damage due to UV radiation have not yet been clarified. We discovered that in one mechanism facilitating damage to wet hair by UV radiation, the unsaturated fatty acids in wet hair produce hydroxy radicals upon exposure to UV radiation, and these radicals produce cuticle holes between the cuticle layers. In wet hair exposed to UV radiation, cuticle holes were produced only between the cuticle layers, whereas when human hair was immersed in a solution containing hydroxy radicals produced by Fenton’s reaction, a random production of cuticle holes was noted. It is thought that hydroxy radicals are produced only between the cuticle layers by exposure to UV radiation, and cuticle holes are formed only in this region because one of the polyunsaturated fatty acids, linoleic acid, with a bis-allyl hydrogen, is found between the cuticle layers.

  15. Selenium inhibits UV-light-induced skin carcinogenesis in hairless mice

    International Nuclear Information System (INIS)

    Overvad, Kim; Thorling, E.B.; Bjerring, Peter; Ebbesen, Peter

    1985-01-01

    Female hairless inbred hr/hr mice were exposed to UV-B irradiation from Philips TL 40W/13 fluorescent tubes. Fractionated irradiation, given as single daily doses 5 days a week, was gradually increased from 0.04 to 0.4 J/cm 2 over 2 weeks. Irradiation at 0.4 J/cm 2 was continued for 20 weeks. Selenium supplementation given as sodium selenite in the drinking water at 2, 4 and 8 mg/l began 3 weeks before UV-irradiation and continued thereafter. Development of skin tumors was followed by weekly examinations. Statistical analyses revealed significant dose-dependent selenium-mediated protection against UV-light-induced skin cancer. Leukemia developed in 5 of 150 UV-irradiated mice as opposed to none in a group of 60 unirradiated mice. (author)

  16. The role of coccoliths in protecting Emiliania huxleyi against stressful light and UV radiation

    Science.gov (United States)

    Xu, Juntian; Bach, Lennart T.; Schulz, Kai G.; Zhao, Wenyan; Gao, Kunshan; Riebesell, Ulf

    2016-08-01

    Coccolithophores are a group of phytoplankton species which cover themselves with small scales (coccoliths) made of calcium carbonate (CaCO3). The reason why coccolithophores form these calcite platelets has been a matter of debate for decades but has remained elusive so far. One hypothesis is that they play a role in light or UV protection, especially in surface dwelling species like Emiliania huxleyi, which can tolerate exceptionally high levels of solar radiation. In this study, we tested this hypothesis by culturing a calcified and a naked strain under different light conditions with and without UV radiation. The coccoliths of E. huxleyi reduced the transmission of visible radiation (400-700 nm) by 7.5 %, that of UV-A (315-400 nm) by 14.1 % and that of UV-B (280-315 nm) by 18.4 %. Growth rates of the calcified strain (PML B92/11) were about 2 times higher than those of the naked strain (CCMP 2090) under indoor constant light levels in the absence of UV radiation. When exposed to outdoor conditions (fluctuating sunlight with UV radiation), growth rates of calcified cells were almost 3.5 times higher compared to naked cells. Furthermore, the relative electron transport rate was 114 % higher and non-photochemical quenching (NPQ) was 281 % higher in the calcified compared to the naked strain, implying higher energy transfer associated with higher NPQ in the presence of calcification. When exposed to natural solar radiation including UV radiation, the maximal quantum yield of photosystem II was only slightly reduced in the calcified strain but strongly reduced in the naked strain. Our results reveal an important role of coccoliths in mitigating light and UV stress in E. huxleyi.

  17. The fungicidal effect of ultraviolet light on impression materials

    International Nuclear Information System (INIS)

    Ishida, H.; Nahara, Y.; Tamamoto, M.; Hamada, T.

    1991-01-01

    The effects of ultraviolet (UV) light on fungi and impression materials were tested. UV light (250 microW/cm2) killed most Candida organisms (10(3) cells/ml) within 5 minutes. UV light (8000 microW/cm2) killed most C. albicans (10(7) cells/ml) within 2 minutes of exposure. The effect of UV light on dimensional change and surface roughness of impression materials (irreversible hydrocolloid, agar, and silicone rubber) was tested. The results showed that neither dimensional change nor surface roughness of the impression materials were affected. The results of this study indicate that UV light disinfects impression materials that are contaminated with Candida organisms

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

    Science.gov (United States)

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

    2017-08-01

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

  19. Induction of DNA deletions after UV-light irradiation in yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Stepanova, A.N.; Koltovaya, N.A.

    2008-01-01

    We study mutagenic action of such a damaging agent as UV light, which can lead to DNA double-strand breaks (DSB). DNA deletions and gross rearrangements occur in process of DSB repair. We show that UV light induces deletion and rearrangement very efficiently. Analysis of efficacy of different types of repair shows that cell tries to repair DSBs with a combination of both homologous recombination (HR) and nonhomologous end joining (NHEJ) if available and that DSB repair by HR is more effective than by NHEJ in growing culture of haploid yeast

  20. UV light-induced thermoluminescence of Er + Li doped ZrO2

    International Nuclear Information System (INIS)

    Hristov, H; Arhangelova, N; Velev, V; Penev, I; Bello, M; Moschini, G; Uzunov, N

    2010-01-01

    Analysis of the thermoluminescence (TL) properties of ZrO 2 doped with Eu and Li has been conducted. Different quantities of lithium co-dopant have been added as Li 2 CO 3 to a mixture of ZrO 2 with 1wt% Er. Pellets sintered at a temperature of 1200 0 C have been prepared and the kinetic parameters of the phosphors have been studied after irradiation with UV light. It has been shown that the addition of 8 to 10 wt% of Li to the mixture of ZrO 2 with 1wt% Er yields a maximum intensity of the peaks at 65 0 C and at 105 0 C. Spectral emission and spectral sensitivity of the phosphors have been studied. The analysis applied to TL glow curves, obtained from the UV irradiated phosphors and kept after the irradiation at different times in a dark storage, revealed that the peaks at 65 0 C and 105 0 C have relatively long fading. It is concluded that the phosphors thus obtained possess a good sensitivity to the UV emission and could be appropriate phosphors for detection and quantitative measurements of UV light.

  1. Study of the UV Light Conversion of Feruloyl Amides from Portulaca oleracea and Their Inhibitory Effect on IL-6-Induced STAT3 Activation.

    Science.gov (United States)

    Hwang, Joo Tae; Kim, Yesol; Jang, Hyun-Jae; Oh, Hyun-Mee; Lim, Chi-Hwan; Lee, Seung Woong; Rho, Mun-Chual

    2016-06-30

    Two new feruloyl amides, N-cis-hibiscusamide (5) and (7'S)-N-cis-feruloylnormetanephrine (9), and eight known feruloyl amides were isolated from Portulaca oleracea L. and the geometric conversion of the ten isolated feruloyl amides by UV light was verified. The structures of the feruloyl amides were determined based on spectroscopic data and comparison with literature data. The NMR data revealed that the structures of the isolated compounds showed cis/trans-isomerization under normal laboratory light conditions. Therefore, cis and trans-isomers of feruloyl amides were evaluated for their convertibility and stability by UV light of a wavelength of 254 nm. After 96 h of UV light exposure, 23.2%-35.0% of the cis and trans-isomers were converted to trans-isomers. Long-term stability tests did not show any significant changes. Among all compounds and conversion mixtures collected, compound 6 exhibited the strongest inhibition of IL-6-induced STAT3 activation in Hep3B cells, with an IC50 value of 0.2 μM. This study is the first verification of the conversion rates and an equilibrium ratio of feruloyl amides. These results indicate that this natural material might provide useful information for the treatment of various diseases involving IL-6 and STAT3.

  2. UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

    Directory of Open Access Journals (Sweden)

    Ricarda Modarressie

    2015-05-01

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

  3. Photoreactivation of UV-irradiated blue-green algae and algal virus LPP-1

    Energy Technology Data Exchange (ETDEWEB)

    Singh, P K [Central Rice Research Inst., Cuttack (India)

    1975-01-01

    Ultraviolet (UV) sensitivity and photoreactivation of blue-green algae Cylindrospermum sp., Plectonema boryanum, spores of Fischerella muscicola and algal virus (cyanophage) LPP-1 were studied. The survival value after UV irradiation of filaments of Cylindrospermum sp. and Virus LPP-1 showed exponential trend and these were comparatively sensitive towards UV than F. muscicola and P. boryanum. Photoreactivation of UV-induced damage occurred in black, blue, green, yellow, red and white light in Cylindrospermum sp., however only black, blue and white light were capable of photorepair of UV-induced damage in P. boryanum, spores of F. muscicola and virus LPP-1 in infected host alga. Pre-exposure to yellow and black light did not show photoprotection. The non-heterocystous and nitrogen fixation-less mutants of Cylindrospermum sp. were not induced by UV and their spontaneous mutation frequency was not affected after photoreactivation. The short trichome mutants of P. boryanum were more resistant towards UV. The occurrence of photoreactivation of UV-induced killing in wide range of light in Cylindrospermum sp. is the first report in organisms.

  4. Development of UV-curable liquid for in-liquid fluorescence alignment in ultraviolet nanoimprint lithography

    Science.gov (United States)

    Ochiai, Kento; Kikuchi, Eri; Ishito, Yota; Kumagai, Mari; Nakamura, Takahiro; Nakagawa, Masaru

    2018-06-01

    We studied a fluorescent UV-curable resin suitable for fluorescence alignment in UV nanoimprinting. The addition of a cationic fluorescent dye caused radical photopolymerization of a UV-curable resin by exposure to visible excitation light for fluorescence microscope observation. The microscope observation of a resin film prepared by pressing resin droplets on a silica substrate with a fluorinated silica superstrate revealed that the cationic dye molecules were preferably adsorbed onto the silica surface. It was indicated that the dye molecules concentrated on the silica surface may cause the photocuring. A nonionic fluorescent dye was selected owing to its low polar symmetrical structure and its solubility parameter close to monomers. The fluorescent UV-curable resin with the nonionic dye showed uncured stability to exposure to visible excitation light for 30 min with a light intensity of 8.5 mW cm‑2 detected at 530 nm.

  5. Increase of vitamin D2 by UV-B exposure during the growth phase of white button mushroom (Agaricus bisporus

    Directory of Open Access Journals (Sweden)

    Hanne L. Kristensen

    2012-04-01

    Full Text Available Background: Mushrooms are the only non-animal food source of vitamin D. Wild mushrooms have naturally high vitamin D2 content, and cultivated mushrooms produce vitamin D2 from ergosterol when exposed to supplementary UV-B during the post-harvest phase.Objectives: This study investigated the effects of providing supplementary UV-B during the growth phase on vitamin D2 formation and the interactions with growth of mushrooms, as compared to supplementary UV-B during the post-harvest phase or exposure to sunlight for both cultivated and wild mushrooms.Methods: Experiments were carried out with exposure to supplementary UV-B just prior to harvest in the range of 0–2,400 mJ cm−2. Mushrooms grew for 2 days with or without repeated UV-B exposure each day. Vitamin D2 and growth rate were determined. In addition, some mushrooms were post-harvest treated by exposure at 200 mJ cm−2 supplementary UV-B or natural sunlight, prior to vitamin D2 determination.Results: The content of vitamin D2 was 0.2–164 µg 100 g−1 fresh weight, and there was a linear relationship between UV-dose up to 1,000 mJ cm−2 and vitamin D2 content. The fast growth rate of the mushrooms diluted the vitamin D2 from 24 to 3 µg 100 g−1 within 2 days of exposure at 200 mJ cm−2. Following repeated UV-B exposure, vitamin D2 increased to 33 µg vitamin D2 100 g−1. Growth was unaffected by UV-B. Post-harvest exposure to supplementary UV-B resulted in a higher vitamin D2 content of 32 µg 100 g−1 compared to the 24 µg 100 g−1 obtained from exposure to UV-B during the growth phase. In contrast, wild and cultivated mushrooms with and without exposure to sunlight had vitamin D2 content in the range of 0.2–1.5 µg vitamin D2 100 g−1.Conclusions: This study showed that mushrooms with a well-defined content of vitamin D2 can be obtained by exposure to supplementary UV-B just prior to harvest.

  6. 78 FR 47320 - Preventing Skin Cancer Through Reduction of UV Exposure

    Science.gov (United States)

    2013-08-05

    ... radiation and a history of sunburn (indicating both intensity of UV exposure and skin sensitivity to... experiencing one or more sunburns in the past 12 months, and sunburn is even more common among younger adults... sun protection is low, while excessive sun exposure, indoor tanning, and sunburn are common. HHS/CDC...

  7. Development of Efficient UV-LED Phosphor Coatings for Energy Saving Solid State Lighting

    International Nuclear Information System (INIS)

    Uwe Happek

    2006-01-01

    The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that describe the performance of the phosphor as a function of photon flux, temperature, and phosphor composition were established. In the second phase of the project, these findings were then implemented to design the improved UV-LED lamp. In addition, our research provides a road map for the design of efficient white light LEDs, which will be an important asset during a follow-up project led by GE

  8. Synthesis of CdSe-TiO_2 Photocatalyst and Their Enhanced Photocatalytic Activities under UV and Visible Light

    International Nuclear Information System (INIS)

    Lim, Chang Sung; Chen, Ming Liang; Oh, Won Chun

    2011-01-01

    In this study, CdSe-TiO_2 photocatalyst were synthesized by a facile solvothermal method and characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and UV-vis diffuse reflectance spectrophotometer. The photocatalytic activity was investigated by degrading methylene blue (MB) in aqueous solution under irradiation of UV light as well as visible light. The absorbance of degraded MB solution was determined by UV-vis spectrophotometer. The results revealed that the CdSe- TiO_2 photocatalyst exhibited much higher photocatalytic activity than TiO_2 both under irradiation of UV light as well as visible light

  9. Evaluation of anogenital injuries using white and UV-light among adult volunteers following consensual sexual intercourse.

    Science.gov (United States)

    Joki-Erkkilä, Minna; Rainio, Juha; Huhtala, Heini; Salonen, Aki; Karhunen, Pekka J

    2014-09-01

    New clinical forensic examination techniques for sexual assaults have not been introduced over the last few decades. We evaluated the benefit of ultraviolet light compared to white light for detecting minor anogenital injuries and scars, following consensual sexual intercourse among adult volunteers. A prospective study comparing female genital findings utilising white and ultraviolet light. A colposcopy with photographic documentation was used. Personal invitation to healthcare students, hospital employees or acquaintances to volunteer for a gynecological examination, with a focus on clinical forensic aspects. Eighty-eight adult female volunteers were recruited for the study. The examination was performed after consensual intercourse. Age ranged from 20 to 52 years (median 26.5 years). Presence of acute findings and scars in the genital area using white and UV-light. Acute genital injury rate was 14.8% under white light colposcopy and 23.0% using UV light. Submucosal hemorrhages in the genital area were documented significantly better under UV-light than white light (14.9% vs. 6.8%; p=0.016), whereas petechiaes (4.5%) and abrasions (2.3%) were detected using either method. UV-light revealed significantly more often delivery-associated genital scars compared to white light (39.8% vs. 31.8%; p=0.016). Furthermore, 10 out of 31 (33.3%) women had no residual anogenital skin or mucosal surface findings, despite a prior episiotomy or rupture of the vaginal outlet wall during delivery, supporting its enormous ability to heal even after major trauma. UV-light may provide additional value for the evaluation of physical findings in clinical forensic examinations after sexual assault, and is especially useful in detecting otherwise invisible early submucosal hemorrhages and scars. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Cell cycle analysis of cultured mammalian cells after exposure to 4,5',8-trimethylpsoralen and long-wave ultraviolet light

    International Nuclear Information System (INIS)

    Cohen, S.R.; Burkholder, D.E.; Varga, J.M.; Carter, D.M.; Bartholomew, J.C.

    1981-01-01

    Cell cycle analysis was used to study the the effect of 4,5'8-trimethylpsoralen (TMP) and long-wave ultraviolet light (UV-A) on cultured mammalian cells. DNA distribution patterns were measured for murine melanoma cells (a cloned line of Cloudman S91) and a strain of diploid human skin fibroblasts (CRL 1295) using both a microfluorimetry procedure and flow cytometry. The untreated cells and those receiving TMP along and UV-A alone had identical DNA content as assessed at several posttreatment intervals (0-72 hr). The majority of cells in control groups contained a G1 DNA content, whereas exposure to TMP (2 x 10(-7) M) plus UV-A (1 Joule/cm2) led to the accumulation of cells in the G2 phase. These observations were similar for each cell type and both analytical techniques were in excellent agreement. The finding that psoralen plus UV-A induces a phase-specific G2 blockade in cultured cells has important implications for understanding the mechanisms which account for enhanced pigmentation and suppression of cellular proliferation following exposure to these agents in vivo

  11. Development of a safe ultraviolet camera system to enhance awareness by showing effects of UV radiation and UV protection of the skin (Conference Presentation)

    Science.gov (United States)

    Verdaasdonk, Rudolf M.; Wedzinga, Rosaline; van Montfrans, Bibi; Stok, Mirte; Klaessens, John; van der Veen, Albert

    2016-03-01

    The significant increase of skin cancer occurring in the western world is attributed to longer sun expose during leisure time. For prevention, people should become aware of the risks of UV light exposure by showing skin damage and the protective effect of sunscreen with an UV camera. An UV awareness imaging system optimized for 365 nm (UV-A) was develop using consumer components being interactive, safe and mobile. A Sony NEX5t camera was adapted to full spectral range. In addition, UV transparent lenses and filters were selected based on spectral characteristics measured (Schott S8612 and Hoya U-340 filters) to obtain the highest contrast for e.g. melanin spots and wrinkles on the skin. For uniform UV illumination, 2 facial tanner units were adapted with UV 365 nm black light fluorescent tubes. Safety of the UV illumination was determined relative to the sun and with absolute irradiance measurements at the working distance. A maximum exposure time over 15 minutes was calculate according the international safety standards. The UV camera was successfully demonstrated during the Dutch National Skin Cancer day and was well received by dermatologists and participating public. Especially, the 'black paint' effect putting sun screen on the face was dramatic and contributed to the awareness of regions on the face what are likely to be missed applying sunscreen. The UV imaging system shows to be promising for diagnostics and clinical studies in dermatology and potentially in other areas (dentistry and ophthalmology)

  12. Maternal exposure to UV filters: associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes.

    Science.gov (United States)

    Krause, M; Frederiksen, H; Sundberg, K; Jørgensen, F S; Jensen, L N; Nørgaard, P; Jørgensen, C; Ertberg, P; Petersen, J H; Feldt-Rasmussen, U; Juul, A; Drzewiecki, K T; Skakkebaek, N E; Andersson, A M

    2018-02-01

    Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo . Exposure to these chemicals, especially during prenatal development, is of concern. To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes. Prospective study of 183 pregnant women with 2nd trimester serum and urine samples available. Maternal concentrations of the chemical UV filters benzophenone-1 (BP-1) and benzophenone-3 (BP-3) in urine and 4-hydroxy-benzophenone (4-HBP) in serum were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships between 2nd trimester maternal concentrations of the three chemical UV filters and maternal serum concentrations of thyroid hormones and growth factors, as well as birth outcomes (weight, height, and head and abdominal circumferences) were examined. Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T 3 ), thyroxine (T 4 ), insulin-like growth factor I (IGF-I) and its binding protein IGFBP3 were observed in mothers carrying male fetuses. Male infants of mothers in the middle 4-HBP exposure group had statistically significantly lower weight and shorter head and abdominal circumferences at birth compared to the low exposure group. Widespread exposure of pregnant women to chemical UV filters and the possible impact on maternal thyroid hormones and growth factors, and on fetal growth, calls for further studies on possible long-term consequences of the exposure to UV filters on fetal development and children's health. © 2018 The authors.

  13. Fish freshness estimation using eye image processing under white and UV lightings

    Science.gov (United States)

    Kanamori, Katsuhiro; Shirataki, Yuri; Liao, Qiuhong; Ogawa, Yuichi; Suzuki, Tetsuhito; Kondo, Naoshi

    2017-05-01

    A non-destructive method of estimating the freshness of fish is required for appropriate price setting and food safety. In particular, for determining the possibility of eating raw fish (sashimi), freshness estimation is critical. We studied such an estimation method by capturing images of fish eyes and performing image processing using the temporal changes of the luminance of pupil and iris. To detect subtle non-visible changes of these features, we used UV (375 nm) light illumination in addition to visible white light illumination. Polarization and two-channel LED techniques were used to remove strong specular reflection from the cornea of the eye and from clear-plastic wrap used to cover the fish to maintain humidity. Pupil and iris regions were automatically detected separately by image processing after the specular reflection removal process, and two types of eye contrast were defined as the ratio of mean and median pixel values of each region. Experiments using 16 Japanese dace (Tribolodon hakonensis) at 23° and 85% humidity for 24 hours were performed. The eye contrast of raw fish increase non-linearly in the initial period and then decreased; however, that of frozen-thawed fish decreased linearly throughout 24 hours, regardless of the lighting. Interestingly, the eye contrast using UV light showed a higher correlation with time than that using white light only in the case of raw fish within the early 6- hour period postmortem. These results show the possibility of estimating fish freshness in the initial stage when fish are eaten raw using white and UV lightings.

  14. an assessment of ultraviolet radiation components of light emitted ...

    African Journals Online (AJOL)

    Dr

    therefore high for exposure limits of 8 hours for UV-B and UV-C and the 16 minutes for UV-A. The investigation ... has become particularly interesting as the ozone layer ... THEORY. Ultraviolet (UV) light is an electromagnetic radiation with a ...

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

    Science.gov (United States)

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

    2016-06-01

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

  16. Red light emitting solid state hybrid quantum dot-near-UV GaN LED devices

    International Nuclear Information System (INIS)

    Song, Hongjoo; Lee, Seonghoon

    2007-01-01

    We produced core-shell (CdSe)ZnSe quantum dots by direct colloidal chemical synthesis and the surface-passivation method-an overcoating of the core CdSe with a larger-bandgap material ZnSe. The (CdSe)ZnSe quantum dots(QDs) play the role of a colour conversion centre. We call these quantum dots nanophosphors. We fabricated red light emitting hybrid devices of (CdSe)ZnSe QDs and a near-UV GaN LED by combining red light emitting (CdSe)ZnSe quantum dots (as a colour conversion centre) with a near-UV(NUV) GaN LED chip (as an excitation source). A few good red phosphors have been known for UV excitation wavelengths, and red phosphors for UV excitation have been sought for a long time. Here we tested the possibility of using (CdSe)ZnSe QDs as red nanophosphors for UV excitation. The fabricated red light emitting hybrid device of (CdSe)ZnSe and a NUV GaN LED chip showed a good luminance. We demonstrated that the (CdSe)ZnSe quantum dots were promising red nanophosphors for NUV excitation and that a red LED made of QDs and a NUV excitation source was a highly efficient hybrid device

  17. Transition metal-modified zinc oxides for UV and visible light photocatalysis.

    Science.gov (United States)

    Bloh, J Z; Dillert, R; Bahnemann, D W

    2012-11-01

    In order to use photocatalysis with solar light, finding more active and especially visible light active photocatalysts is a very important challenge. Also, studies of these photocatalysts should employ a standardized test procedure so that their results can be accurately compared and evaluated with one another. A systematic study of transition metal-modified zinc oxide was conducted to determine whether they are suitable as visible light photocatalysts. The photocatalytic activity of ZnO modified with eight different transition metals (Cu, Co, Fe, Mn, Ni, Ru, Ti, Zr) in three different concentrations (0.01, 0.1, and 1 at.%) was investigated under irradiation with UV as well as with visible light. The employed activity test is the gas-phase degradation of acetaldehyde as described by the ISO standard 22197-2. The results suggest that the UV activity can be improved with almost any modification element and that there exists an optimal modification ratio at about 0.1 at.%. Additionally, Mn- and Ru-modified ZnO display visible light activity. Especially the Ru-modified ZnO is highly active and surpasses the visible light activity of all studied titania standards. These findings suggest that modified zinc oxides may be a viable alternative to titanium dioxide-based catalysts for visible light photocatalysis. Eventually, possible underlying mechanisms are proposed and discussed.

  18. 207-nm UV Light—A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. II: In-Vivo Safety Studies

    Science.gov (United States)

    Buonanno, Manuela; Stanislauskas, Milda; Ponnaiya, Brian; Bigelow, Alan W.; Randers-Pehrson, Gerhard; Xu, Yanping; Shuryak, Igor; Smilenov, Lubomir; Owens, David M.; Brenner, David J.

    2016-01-01

    Background UVC light generated by conventional germicidal lamps is a well-established anti-microbial modality, effective against both bacteria and viruses. However, it is a human health hazard, being both carcinogenic and cataractogenic. Earlier studies showed that single-wavelength far-UVC light (207 nm) generated by excimer lamps kills bacteria without apparent harm to human skin tissue in vitro. The biophysical explanation is that, due to its extremely short range in biological material, 207 nm UV light cannot penetrate the human stratum corneum (the outer dead-cell skin layer, thickness 5–20 μm) nor even the cytoplasm of individual human cells. By contrast, 207 nm UV light can penetrate bacteria and viruses because these cells are physically much smaller. Aims To test the biophysically-based hypothesis that 207 nm UV light is not cytotoxic to exposed mammalian skin in vivo. Methods Hairless mice were exposed to a bactericidal UV fluence of 157 mJ/cm2 delivered by a filtered Kr-Br excimer lamp producing monoenergetic 207-nm UV light, or delivered by a conventional 254-nm UV germicidal lamp. Sham irradiations constituted the negative control. Eight relevant cellular and molecular damage endpoints including epidermal hyperplasia, pre-mutagenic UV-associated DNA lesions, skin inflammation, and normal cell proliferation and differentiation were evaluated in mice dorsal skin harvested 48 h after UV exposure. Results While conventional germicidal UV (254 nm) exposure produced significant effects for all the studied skin damage endpoints, the same fluence of 207 nm UV light produced results that were not statistically distinguishable from the zero exposure controls. Conclusions As predicted by biophysical considerations and in agreement with earlier in vitro studies, 207-nm light does not appear to be significantly cytotoxic to mouse skin. These results suggest that excimer-based far-UVC light could potentially be used for its anti-microbial properties, but without

  19. CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

    Science.gov (United States)

    Wu, Jie; Liu, Baibai; Ren, Zhenxing; Ni, Mengying; Li, Can; Gong, Yinyan; Qin, Wei; Huang, Yongli; Sun, Chang Q; Liu, Xinjuan

    2018-05-01

    To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions. As co-catalyst, RGO can separate and inhibit the recombination of charge carriers, consequently improving the catalytic activity. Only 1wt% RGO emersions can reduce 90% of Cr(VI) under the radiation of light over the full spectrum. Findings may provide a new strategy and substance to expand the utilization range of solar light from UV to visible even the NIR energy. Copyright © 2017. Published by Elsevier Inc.

  20. Impact of fouling on UV effectiveness

    International Nuclear Information System (INIS)

    Dykstra, T.S.; Chauret, C.

    2002-01-01

    In recent years ultraviolet light has gained in popularity as an attractive disinfection alternative due to its ability to inactivate bacteria and viruses. UV light has the potential to inactivate Cryptosporidium parvum and Giardia lamblia with a very low potential for the formation of harmful disinfection by-products. Previous studies have reported that particulate material present in the water can act to reduce the exposure of UV light to the receiving waters and that the interference of organic particles can serve to protect bacteria and viruses from intended disinfection. Disinfection capacity can also be reduced by organics in the source water that can accumulate on the surface of quartz sleeves. The purpose of this study was to determine the ability of a medium pressure UV light, at drinking water treatment levels, to inactivate MS 2 bacteriophage after a quartz tube has been fouled with organic rich source water for a 12- week period. To this end the inactivation of MS 2 was determined under clean and fouled conditions, in the presence and absence of humic rich water. The effect of lamp age on inactivation was also investigated. The results suggest that organic fouling of a quartz tube has a significant impact on the disinfection capacity of a medium pressure UV lamp. The presence of organics in the source water also plays a significant role in reducing the capacity of UV for bacterial and viral disinfection. Lamp age also seems to have some effect on the efficiency of UV disinfection. (author)

  1. Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation

    International Nuclear Information System (INIS)

    Harlow, G.R.; Jenkins, M.E.; Pittalwala, T.S.; Mount, D.W.

    1994-01-01

    A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage

  2. Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Harlow, G. R.; Jenkins, M. E.; Pittalwala, T. S.; Mount, D. W.

    1994-02-15

    A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage.

  3. Challenges of UV light processing of low UVT foods and beverages

    Science.gov (United States)

    Koutchma, Tatiana

    2010-08-01

    Ultraviolet (UV) technology holds promise as a low cost non-thermal alternative to heat pasteurization of liquid foods and beverages. However, its application for foods is still limited due to low UV transmittance (LUVT). LUVT foods have a diverse range of chemical (pH, Brix, Aw), physical (density and viscosity) and optical properties (absorbance and scattering) that are critical for systems and process designs. The commercially available UV sources tested for foods include low and medium pressure mercury lamps (LPM and MPM), excimer and pulsed lamps (PUV). The LPM and excimer lamps are monochromatic sources whereas emission of MPM and PUV is polychromatic. The optimized design of UV-systems and UV-sources with parameters that match to specific product spectra have a potential to make UV treatments of LUVT foods more effective and will serve its further commercialization. In order to select UV source for specific food application, processing effects on nutritional, quality, sensorial and safety markers have to be evaluated. This paper will review current status of UV technology for food processing along with regulatory requirements. Discussion of approaches and results of measurements of chemico-physical and optical properties of various foods (fresh juices, milk, liquid whey proteins and sweeteners) that are critical for UV process and systems design will follow. Available UV sources did not prove totally effective either resulting in low microbial reduction or UV over-dosing of the product thereby leading to sensory changes. Beam shaping of UV light presents new opportunities to improve dosage uniformity and delivery of UV photons in LUVT foods.

  4. Skin protection against UV light by dietary antioxidants.

    Science.gov (United States)

    Fernández-García, Elisabet

    2014-09-01

    There is considerable interest in the concept of additional endogenous photoprotection by dietary antioxidants. A number of efficient micronutrients are capable of contributing to the prevention of UV damage in humans. These compounds protect molecular targets by scavenging reactive oxygen species, including excited singlet oxygen and triplet state molecules, and also modulate stress-dependent signaling and/or suppress cellular and tissue responses like inflammation. Micronutrients present in the diet such as carotenoids, vitamins E and C, and polyphenols contribute to antioxidant defense and may also contribute to endogenous photoprotection. This review summarizes the literature concerning the use of dietary antioxidants as systemic photoprotective agents towards skin damage induced by UVA and UVB. Intervention studies in humans with carotenoid-rich diets have shown photoprotection. Interestingly, rather long treatment periods (a minimum of 10 weeks) were required to achieve this effect. Likewise, dietary carotenoids exert their protective antioxidant function in several in vitro and in vivo studies when present at sufficiently high concentration. A combination of vitamins E and C protects the skin against UV damage. It is suggested that daily consumption of dietary polyphenols may provide efficient protection against the harmful effects of solar UV radiation in humans. Furthermore, the use of these micronutrients in combination may provide an effective strategy for protecting human skin from damage by UV exposure.

  5. Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters.

    Science.gov (United States)

    Sigaev, Vladimir N; Golubev, Nikita V; Ignat'eva, Elena S; Paleari, Alberto; Lorenzi, Roberto

    2014-01-01

    Wide-bandgap nanocrystals are an inexhaustible source of tuneable functions potentially addressing most of the demand for new light emitting systems. However, the implementation of nanocrystal properties in real devices is not straightforward if a robust and stable optical component is required as a final result. The achievement of efficient light emission from dense dispersions of Ga-oxide nanocrystals in UV-grade glass can be a breakthrough in this regard. Such a result would permit the fabrication of low cost UV-to-visible converters for monitoring UV-emitting events on a large-scale - from invisible hydrogen flames to corona dispersions. From this perspective, γ-Ga₂O₃ nanocrystals are developed by phase separation in Ga-alkali-germanosilicate glasses, obtaining optical materials based on a UV transparent matrix. Band-to-band UV-excitation of light emission from donor-acceptor pair (DAP) recombination is investigated for the first time in embedded γ-Ga₂O₃. The analysis of the decay kinetics gives unprecedented evidence that nanosized confinement of DAP recombination can force a nanophase to the efficient response of exactly balanced DAPs. The results, including a proof of concept of UV-to-visible viewer, definitely demonstrate the feasibility of workable glass-based fully inorganic nanostructured materials with emission properties borrowed from Ga₂O₃ single-crystals and tailored by the nanocrystal size.

  6. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds. Livsstil, soling og bruning - hva med UV-A solarier

    Energy Technology Data Exchange (ETDEWEB)

    Thune, P [Ullevaal Sykehus, Oslo (Norway)

    1991-06-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab.

  7. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds. Livsstil, soling og bruning - hva med UV-A solarier

    Energy Technology Data Exchange (ETDEWEB)

    Thune, P. (Ullevaal Sykehus, Oslo (Norway))

    1991-06-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab.

  8. Plasmid-associated sensitivity of Bacillus thuringiensis to UV light

    International Nuclear Information System (INIS)

    Benoit, T.G.; Wilson, G.R.; Bull, D.L.; Aronson, A.I.

    1990-01-01

    Spores and vegetative cells of Bacillus thuringiensis were more sensitive to UV light than were spores or cells of plasmid-cured B. thuringiensis strains or of the closely related Bacillus cereus. Introduction of B. thuringiensis plasmids into B. cereus by cell mating increased the UV sensitivity of the cells and spores. Protoxins encoded by one or more B. thuringiensis plasmids were not involved in spore sensitivity, since a B. thuringiensis strain conditional for protoxin accumulation was equally sensitive at the permissive and nonpermissive temperatures. In addition, introduction of either a cloned protoxin gene, the cloning vector, or another plasmid not containing a protoxin gene into a plasmid-cured strain of B. thuringiensis all increased the UV sensitivity of the spores. Although the variety of small, acid-soluble proteins was the same in the spores of all strains examined, the quantity of dipicolinic acid was about twice as high in the plasmid-containing strains, and this may account for the differences in UV sensitivity of the spores. The cells of some strains harboring only B. thuringiensis plasmids were much more sensitive than cells of any of the other strains, and the differences were much greater than observed with spores

  9. Atmospheric fate of oil matter adsorbed on sea salt particles under UV light

    Science.gov (United States)

    Vaitilingom, M.; Avij, P.; Huang, H.; Valsaraj, K. T.

    2014-12-01

    The presence of liquid petroleum hydrocarbons at the sea water surface is an important source of marine pollution. An oil spill in sea-water will most likely occur due to an involuntary accident from tankers, offshore platforms, etc. However, a large amount of oil is also deliberately spilled in sea-water during the clean-out process of tank vessels (e.g. for the Mediterranean Sea, 490,000 tons/yr). Moreover, the pollution caused by an oil spill does not only affect the aquatic environment but also is of concern for the atmospheric environment. A portion of the oil matter present at the sea-water surface is transported into the atmosphere viaevaporation and adsorption at the surface of sea spray particles. Few studies are related to the presence of oil matter in airborne particles resulting from their adsorption on sea salt aerosols. We observed that the non-volatile oil matter was adsorbed at the surface of sea-salt crystals (av. size of 1.1 μm). Due to their small size, these particles can have a significant residence time in the atmosphere. The hydrocarbon matter adsorbed at the surface of these particles can also be transformed by catalyzers present in the atmosphere (i.e. UV, OH, O3, ...). In this work, we focused on the photo-oxidation rates of the C16 to C30alkanes present in these particles. We utilized a bubble column reactor, which produced an abundance of small sized bubbles. These bubbles generated droplets upon bursting at the air-salt water interface. These droplets were then further dried up and lifted to the top of the column where they were collected as particles. These particles were incubated in a controlled reactor in either dark conditions or under UV-visible light. The difference of alkane content analyzed by GC-MS between the particles exposed to UV or the particles not exposed to UV indicated that up to 20% in mass was lost after 20 min of light exposure. The degradation kinetics varied for each range of alkanes (C16-20, C21-25, C26

  10. Fundamental Scaling of Microplasmas and Tunable UV Light Generation.

    Energy Technology Data Exchange (ETDEWEB)

    Manginell, Ronald P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sillerud, Colin Halliday [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hopkins, Matthew M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yee, Benjamin Tong [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moorman, Matthew W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schwindt, Peter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, John Moses [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pfeifer, Nathaniel Bryant [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-11-01

    The temporal evolution of spectral lines from microplasma devices (MD) was studied, including impurity transitions. Long-wavelength emission diminishes more rapidly than deep UV with decreasing pulse width and RF operation. Thus, switching from DC to short pulsed or RF operation, UV emissions can be suppressed, allowing for real-time tuning of the ionization energy of a microplasma photo-ionization source, which is useful for chemical and atomic physics. Scaling allows MD to operate near atmospheric pressure where excimer states are efficiently created and emit down to 65 nm; laser emissions fall off below 200 nm, making MD light sources attractive for deep UV use. A first fully-kinetic three-dimensional model was developed that explicitly calculates electron-energy distribution function. This, and non-continuum effects, were studied with the model and how they are impacted by geometry and transient or DC operation. Finally, a global non-dimensional model was developed to help explain general trends MD physics.

  11. Effect of grape bunch sunlight exposure and UV radiation on phenolics and volatile composition of Vitis vinifera L. cv. Pinot noir wine.

    Science.gov (United States)

    Song, Jianqiang; Smart, Richard; Wang, Hua; Dambergs, Bob; Sparrow, Angela; Qian, Michael C

    2015-04-15

    The effect of canopy leaf removal and ultraviolet (UV) on Pinot noir grape and wine composition was investigated in this study. Limited basal leaf removal in the fruit zone was conducted, compared to shaded bunches. The UV exposure was controlled using polycarbonate screens to block UV radiation, and acrylic screens to pass the UV. The results showed that bunch sunlight and UV exposure significantly increased the Brix and pH in the grape juice, and increased substantially wine colour density, anthocyanins, total pigment, total phenolics and tannin content. Bunch sunlight and UV exposure affected terpene alcohols, C13-norisprenoids and other volatile composition of the wine differently. Sunlight exposure and UV resulted in increase of nerol, geraniol and citronellol but not linalool. Sunlight exposure slightly increased the concentration of β-ionone, but the increase was not statistically significant for UV treatment. Neither sunlight nor UV treatment showed any impact on the concentration of β-damascenone. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Short-term UV-B radiation and ozone exposure effects on aromatic secondary metabolite accumulation and shoot growth of flavonoid-deficient Arabidopsis mutants

    International Nuclear Information System (INIS)

    Ormrod, D.P.; Landry, L.G.; Conklin, P.L.

    1995-01-01

    The presence of UV-absorptive substances in the epidermal cells of leaves is thought to protect mesophyll tissues from the harmful effects of UV-B radiation. We examined the influence of short-term UV-B exposures on UV-absorptive (330 nm) sinapates and flavonols, and on shoot growth of the Arabidopsis wild type ecotype Landsberg erecta and two mutants. 114 deficient in chalcone synthase, and 115, deficient in chalcone/flavonone isomerase. Sequential ozone exposures were used to determine the effects of oxidative stress The levels of sinapates and flavonols on a leaf fresh weight basis increased substantially in the wild type and sinapates increased in the 114 mutant in vegetative vegetative/reproductive transitional and reproductive stage plants in response to short-term (48h) UV-B radiation. When UV-B was discontinued the levels generally decreased lo pre-exposure levels after 48 h in vegetative/reproductive but not in reproductive plants. Exposure to ozone before or alter UV-B treatment did not consistently affect the levels of these UV-absorptive compounds. Dry matter accumulation was less affected by UV-B at the vegetative and reproductive stages than at the vegetative/reproductive stage. At the vegetative/reproductive stage, shoot growth of all 3 genotypes was retarded by UV-B. Growth was not retarded by short-term ozone exposure alone but when exposure to ozone followed UV-B exposure, growth was reduced in all genotypes. Leaf cupping appeared on 115 plants exposed to UV-B

  13. The effects of near-UV radiation on elasmobranch lens cytoskeletal actin.

    Science.gov (United States)

    Zigman, S; Rafferty, N S; Scholz, D L; Lowe, K

    1992-08-01

    The role of near-UV radiation as a cytoskeletal actin-damaging agent was investigated. Two procedures were used to analyse fresh smooth dogfish (Mustelus canis) eye lenses that were incubated for up to 22 hr in vitro, with elasmobranch Ringer's medium, and with or without exposure to a near-UV lamp (emission principally at 365 nm; irradiance of 2.5 mW cm-2). These were observed histologically using phalloidin-rhodamine specific staining and by transmission electron microscopy. In addition, solutions of purified polymerized rabbit muscle actin were exposed to the same UV conditions and depolymerization was assayed by ultracentrifugation and high-pressure liquid chromatography. While the two actins studied do differ very slightly in some amino acid sequences, they would react physically nearly identically. The results showed that dogfish lenses developed superficial opacities due to near-UV exposure. Whole mounts of lens epithelium exhibited breakdown of actin filaments in the basal region of the cells within 18 hr of UV exposure. TEM confirmed the breakdown of actin filaments due to UV exposure. SDS-PAGE and immunoblotting positively identified actin in these cells. Direct exposure of purified polymerized muscle actin in polymerizing buffer led to an increase in actin monomer of approximately 25% in the UV-exposed solutions within 3-18 hr, whether assayed by ultracentrifugation or HPLC. The above indicates that elasmobranch lens epithelial cells contain UV-labile actin filaments, and that near-UV radiation, as is present in the sunlit environment, can break down the actin structure in these cells. Furthermore, breakdown of purified polymerized muscle actin does occur due to near-UV light exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Fluorescence image excited by a scanning UV-LED light

    Science.gov (United States)

    Tsai, Hsin-Yi; Chen, Yi-Ju; Huang, Kuo-Cheng

    2013-03-01

    An optical scanning system using UV-LED light to induced fluorescence technology can enhance a fluorescence image significantly in a short period. It has several advantages such as lower power consumption, no scattering effect in skins, and multilayer images can be obtained to analyze skin disease. From the experiment results, the light intensity increases with increase spot size and decrease scanning speed, but the image resolution is oppositely. Moreover, the system could be widely used in clinical diagnosis and photodynamic therapy for skin disease because even the irradiated time of fluorescence substance is short but it will provide accurately positioning of fluorescence object.

  15. Vitamin C affects the antioxidative/oxidative status in rats irradiated with ultraviolet (UV) and infrared (IR) light

    DEFF Research Database (Denmark)

    Niemiec, T.; Sawosz, E.; Chwalibog, André

    2006-01-01

    Four grups of twenty growing Wistar rats were irradiated with either UV, IR, UV+IR light or were not irradiated (control). Ten rats from each group received a diet supplemented with 0.6% of L-ascorbic acid. The effects of the mega-dose of vitamin C were evaluated by changes in the antioxidative....../oxidative status. UV and IR radiation promoted oxidative DNA degradation in rat livers and supplementation with ascorbic acid strengthened the prooxidative effects on DNA oxidation in rats irradiated with UV or IR light. Vitamin C also increased the tiobarbituric acid reactive substances (TBARS) concentration...

  16. UV-visible light photocatalytic properties of NaYF4:(Gd, Si)/TiO2 composites

    Science.gov (United States)

    Mavengere, Shielah; Kim, Jung-Sik

    2018-06-01

    In this study, a new novel composite photocatalyst of NaYF4:(Gd, Si)/TiO2 phosphor has been synthesized by two step method of solution combustion and sol-gel. The photocatalyst powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV-vis spectroscopy and photoluminescence (PL) spectroscopy. Raman spectroscopy confirmed the anatase TiO2 phase which remarkably increased with existence of yttrium silicate compounds between 800 cm-1 and 900 cm-1. Double-addition of Gd3+-Si4+ ions in NaYF4 host introduced sub-energy band levels with intense absorption in the ultraviolet (UV) light region. Photocatalytic activity was examined by exposing methylene blue (MB) solutions mixed with photocatalyst powders to 254 nm UV-C fluorescent lamp and 200 W visible lights. The UV and visible photocatalytic reactivity of the NaYF4:(Gd, 1% Si)/TiO2 phosphor composites showed enhanced MB degradation efficiency. The coating of NaYF4:(Gd, 1% Si) phosphor with TiO2 nanoparticles creates energy band bending at the phosphor/TiO2 interfaces. Thus, these composites exhibited enhanced absorption of UV/visible light and the separation of electron and hole pairs for efficient photocatalysis.

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

    Science.gov (United States)

    Beblo, Kristina; Douki, Thierry; Schmalz, Gottfried; Rachel, Reinhard; Wirth, Reinhard; Huber, Harald; Reitz, Günther; Rettberg, Petra

    2011-11-01

    In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylogenetically 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 hyperthermophilic microorganisms.

  18. The response of bean plants to UV-B radiation under different irradiances of background visible light

    International Nuclear Information System (INIS)

    Cen, Y.P.; Bornman, J.F.

    1990-01-01

    Plants of Phaseolus vulgaris L. (cv. Stella) were grown in controlled conditions under three different irradiances of visible light with or without UV-B (280–320nm) radiation. The biologically effective UV-B radiation (UV-BBE) was 6.17 kJ m −2 d −1 , and simulated a c. 5% decrease in stratospheric ozone at 55.7°N, 13.4°E. The photon flux densities of the photosynthetically active radiation (PAR, 400–700 nm) were either 700 μmol m −2−1 (HL), 500, μmol m −2 s −1 (ML) or 230 μmol m −2 s −1 PAR (LL). Under high light (HL) conditions plus UV-B radiation, bean plants appeared most resistant to the enhanced levels of UV-B radiation, and responded only by increasing leaf thickness by c. 18%. A small increase in UV screening pigments was also observed. Both the lower irradiances (ML and LL) increased the sensitivity of the plants to UV-B radiation. Changes in leaf structure were also observed. Photosystem II was inhibited under ML and LL together with UV-B radiation, as determined by Chi fluorescence induction and calculation of the fluorescence half-rise times. Leaf reflectivity measurements showed that the amount of PAR able to penetrate leaves of UV-B treated plants was reduced, and that a possible correlation may exist between the reduced PAR levels, loss of Chi and lowered photosynthetic activity, especially for LL +UV-B grown plants, where surface reflection from leaves was highest. Changes in leaf chlorophyll content were mostly confined to plants grown under LL + UV-B, where a decrease of c. 20% was found. With regard to protective pigments (the carotenoids and UV screening pigments) plants subjected to different visible light conditions responded differently. Among the growth parameters measured, there was a substantial decrease in leaf area, particularly under LL + UV-B (c. 47% relative to controls), where leaf dry weight was also reduced by c. 25%. (author)

  19. UV-induced photochemical transformations of citrate-capped silver nanoparticle suspensions

    International Nuclear Information System (INIS)

    Gorham, Justin M.; MacCuspie, Robert I.; Klein, Kate L.; Fairbrother, D. Howard; Holbrook, R. David

    2012-01-01

    Due to the increasing use of silver nanoparticles (AgNPs) in consumer products, it is essential to understand how variables, such as light exposure, may change the physical and chemical characteristics of AgNP suspensions. To this end, the effect of 300 nm ultraviolet (UV) light on (20, 40, 60 and 80) nm citrate-capped AgNP suspensions has been investigated. As a consequence of irradiation, the initial yellow hue of the AgNP suspensions is transformed towards a near colorless solution due to the loss of the surface plasmon resonance (SPR) absorbance. The decrease in SPR absorbance followed a first-order decay process for all particle sizes with a rate constant that increased linearly with the AgNP specific surface area and non-linearly with light intensity. The rate of loss of the SPR absorbance decreased with increasing citrate concentration, suggesting a surface-mediated transformation. Absorbance, atomic force microscopy, and dynamic light scattering results all indicated that AgNP photolysis was accompanied by a diameter decrease and occasional aggregation. Furthermore, in situ transmission electron microscopy imaging using a specialized liquid cell also showed a decrease in the particle size and the formation of a core–shell structure in UV-exposed AgNPs. X-ray photoelectron spectroscopy analysis suggested that this shell consisted of oxidized silver. The SPR in UV-exposed AgNP suspensions could be regenerated by addition of a strong reducing agent (NaBH 4 ), supporting the idea that oxidized silver is present after photolysis. Evidence for UV-enhanced dissolution and the production of silver ions was obtained with the Donnan membrane technique. This study reveals that the physico-chemical properties of aqueous AgNP suspensions will change significantly upon exposure to UV light, with implications for environmental health and safety risk assessments.

  20. A reversible conductivity modulation of azobenzene-based ionic liquids in aqueous solutions using UV/vis light.

    Science.gov (United States)

    Li, Zhiyong; Yuan, Xiaoqing; Feng, Ying; Chen, Yongkui; Zhao, Yuling; Wang, Huiyong; Xu, Qingli; Wang, Jianji

    2018-05-09

    Photo-induced conductivity modulation of stimuli-responsive materials is of great importance from the viewpoint of fundamental research and technology. In this work, 5 new kinds of azobenzene-based photo-responsive ionic liquids were synthesized and characterized, and UV/vis light modulation of their conductivity was investigated in an aqueous solution. The factors affecting the conductivity modulation of the photo-responsive fluids, such as photo-isomerization efficiency, photo-regulation aggregation, concentration and chemical structure of the ionic liquids, were examined systematically. It was found that the conductivity of the ionic liquids in water exhibited a significant increase upon UV light irradiation and the ionic liquids with a shorter alkyl spacer in the cation showed a more remarkable photo-induced conductivity enhancement with a maximum increase of 150%. In addition, the solution conductivity was restored (or very close) to the initial value upon an alternative irradiation with visible light. Thus, the solution conductivity can be modulated using alternative irradiation with UV and visible light. Although the reversible photo-isomerization of the azobenzene group under UV/vis irradiation is the origin of the conductivity modulation, the photo-regulated aggregation of the ionic liquid in water is indispensable for the maximum degree of conductivity modulation because UV irradiation can weaken, even break the aggregated cis-isomers of the ionic liquids in an aqueous solution.

  1. Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes

    International Nuclear Information System (INIS)

    Karabourniotis, G.; Bornman, J.F.

    1999-01-01

    Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development. (author)

  2. Bromodeoxyuridine combined with UV light and gamma irradiation promotes the production of asymmetric somatic hybrid calli

    International Nuclear Information System (INIS)

    Trick, H.N.; Bates, G.W.

    1996-01-01

    The degree of gamma‐ or X‐ray‐induced donor chromosome elimination in asymmetric somatic hybrids is highly variable. Here the beneficial use of bromodeoxyuridine and UV light as additional chromosome destabilizing agents is described. Protoplasts of Nicotiana tabacum were fused with protoplasts of Nicotiana plumbaginifolia (Np) that carried the kanamycin‐resistance and glucuronidase (GUS) genes on separate chromosomes. Prior to fusion, the Np donor protoplasts were pretreated with bromodeoxyuridine and then were inactivated by treatment with iodoacetate ± UV light ± 200 Gy gamma irradiation. Hybrids were selected on medium containing kanamycin. The elimination of Np DNA was assessed by scoring of the fraction of hybrid calli that expressed GUS and by dot‐blot analysis using a Np‐specific probe. gamma irradiation alone resulted in elimination of 50% of Np DNA. Pretreatment with bromodeoxyuridine (10 μM) followed by 2.5 to 5 min UV light resulted in the elimination of 35–45% of the donor genome, but incorporation of bromodeoxyuridine (10 μM) followed by 2,5 to 5 min UV light and 200 Gy gamma irradiation resulted in 85 to 90% elimination of Np DNA

  3. Investigation of L(+)-Ascorbic Acid with Raman Spectroscopy in Visible and UV Light

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    2015-01-01

    Abstract: Raman spectroscopy investigations of l(+)-ascorbic acid and its mono- and di-deprotonated anions (AH(-) and A(2-)) are reviewed and new measurements reported with several wavelengths, 229, 244, 266, 488, and 532nm. Results are interpreted, assisted by new DFT/B3LYP quantum chemical calc......). Relatively weak preresonance enhancement was seen for A(2-) when excitation was done with 229nm UV light, allowing water bands to become observable as for normal visible light Raman spectra....... calculations with 6-311++G(d,p) basis sets for several conformations of ascorbic acid and the anions. Raman spectra were measured during titration with NaOH base in an oxygen-poor environment to avoid fluorescence when solutions were alkaline. The ultraviolet (UV) absorption band for ascorbic acid in aqueous......cm(-1). Finally, for the ascorbate di-anion, absorption was found at similar to 298.4nm with molar absorptivity of similar to 7,000 L mol(-1) cm(-1) and below similar to 220nm. With UV light (244 and 266nm), strongly basic solutions gave pronounced Raman resonance enhancement at similar to 1556cm(-1...

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

    Science.gov (United States)

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

    2013-04-01

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

  5. INACTIVATION OF PATHOGENIC BACTERIA USING PULSED UV-LIGHT AND ITS APPLICATION IN WATER DISINFECTION AND QUALITY CONTROL

    Directory of Open Access Journals (Sweden)

    M. K. Sharifi-Yazdi H. Darghahi

    2006-09-01

    Full Text Available The lethality of pulsed ultra-violet (UV rich light for the inactivation of pathogenic bacteria has been investigated. A low pressure xenon filled flash lamps that produced UV intensities have been used. The pulsed operation of the system enable the release of electrical energy stored in the capacitor into the flash lamp within a short time and produces the high current and high peak power required for emitting the intense UV flash. The flash frequency was adjusted to one pulse per second. Several types of bacteria were investigated for their susceptibility to pulsed UV illumination. The treated bacterial populations were reduced and determined by direct viable counts. Among the tested bacteria Pseudomonas aeruginosa was the most susceptible to the pulsed UV- light with a 8 log10 cfu/ml reduction after 11 pulses, while the spores of Bacillus megaterium was the most resistant and only 4 log10 cfu/ml reduction achieved after 50 pulses of illumination. The results of this study demonstrated that pulsed UV- light technology could be used as an effective method for the inactivation, of pathogenic bacteria in different environments such as drinking water.

  6. UV ATTENUATION NEAR CORAL REEFS IN THE FLORIDA KEYS: LIGHT ABSORPTION BY CDOM AND PARTICLES

    Science.gov (United States)

    We have investigated the roles of chromophoric dissolved organic matter (CDOM) and suspended particles in the attenuation of UV radiation in the middle and lower regions of the Florida Keys. Extended exposure to UV radiation, along with elevated sea surface temperatures, impairs...

  7. 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.

  8. Influence of occupational exposure to pesticides on the level of DNA damage induced in human lymphocytes (Polish group) by UV-C and X-rays

    International Nuclear Information System (INIS)

    Dyga, W.; Drag, Z.; Cebulska-Wasilewska, A.

    2002-01-01

    The aim of this study was to find out whether occupational exposure to pesticides might affect the individual susceptibility of various donors to the induction of DNA damage by genotoxic agents (UV-C, X-rays) and the efficiency of cellular repair. Previously cryo preserved lymphocytes were defrosted, and DNA damage in the lymphocytes prior to any in vitro studies was investigated with the application of the Comet assay. In order to evaluate the susceptibilities of human lymphocytes to genotoxic agents and the variability of repair capacities, the DNA migrations were estimated immediately after exposure to UV-C light or X-rays and after two hours. On average, the DNA damage detected in untreated lymphocytes was significantly higher in the group exposed to pesticides than in reference group. UV-C treated lymphocytes from group exposed to pesticides shows a greater statistically significant level of DNA migration compared to the reference group, detected after 2 hours incubation in the absence of PHA. Significantly lower responses to X-rays and higher levels of residual DNA damage were detected in the lymphocytes of donors from the group exposed to pesticides compared with the reference group. In conclusion, our results suggest that occupational exposure to pesticides influences the level of induced DNA damage, and the cellular capabilities of repair. (author)

  9. Quantifying light exposure patterns in young adult students

    Science.gov (United States)

    Alvarez, Amanda A.; Wildsoet, Christine F.

    2013-08-01

    Exposure to bright light appears to be protective against myopia in both animals (chicks, monkeys) and children, but quantitative data on human light exposure are limited. In this study, we report on a technique for quantifying light exposure using wearable sensors. Twenty-seven young adult subjects wore a light sensor continuously for two weeks during one of three seasons, and also completed questionnaires about their visual activities. Light data were analyzed with respect to refractive error and season, and the objective sensor data were compared with subjects' estimates of time spent indoors and outdoors. Subjects' estimates of time spent indoors and outdoors were in poor agreement with durations reported by the sensor data. The results of questionnaire-based studies of light exposure should thus be interpreted with caution. The role of light in refractive error development should be investigated using multiple methods such as sensors to complement questionnaires.

  10. Repeated exposure to enhanced UV-B radiation in successive generations increases developmental instability (leaf fluctuating asymmetry) in a desert annual

    International Nuclear Information System (INIS)

    Midgley, G.F.; Wand, S.J.E.; Musil, C.F.

    1998-01-01

    Populations of the desert annual Dimorphotheca sinuata, derived from a common seed stock, were exposed concurrently over four successive generations to either ambient (representing no stratospheric ozone depletion) or elevated (representing 20% stratospheric ozone depletion) UV-B levels during their complete life cycle. Leaf fluctuating asymmetry (FA) was measured in populations of plants grown from seeds of selected generations which had experienced different UV-B exposure histories, and from seeds collected from a wild population of this species which grows in a naturally enhanced UV-B environment. These measured plants had been grown in a greenhouse under essentially UV-B-free conditions. Leaf FA was significantly increased by greater numbers of enhanced UV-B exposures in the parentage of the seed. There was a linear to exponential dose–response relationship between number of UV-B exposure iterations in seed parentage and leaf FA, suggesting that damage to DNA caused by UV-B exposure during plant development may not be fully repaired, and thus be inherited by offspring and accumulated over successive generations in this species. Leaf FA of plants grown from seed from the wild population was not significantly greater than that of control plants whose parentage experienced only ambient UV-B exposures, although this negative result may have been due to low sampling intensity and measurement resolution, and the relatively low UV-B enhancement experienced by the wild population. We conclude that leaf FA may constitute a relatively sensitive yet inexpensive means of quantifying UV-B damage to plants. (author)

  11. Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis

    Science.gov (United States)

    Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

    2017-01-01

    Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways. PMID:28277539

  12. Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis.

    Science.gov (United States)

    Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

    2017-03-09

    Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways.

  13. NGF protects corneal, retinal, and cutaneous tissues/cells from phototoxic effect of UV exposure.

    Science.gov (United States)

    Rocco, Maria Luisa; Balzamino, Bijorn Omar; Aloe, Luigi; Micera, Alessandra

    2018-04-01

    Based on evidence that nerve growth factor (NGF) exerts healing action on damaged corneal, retinal, and cutaneous tissues, the present study sought to assess whether topical NGF application can prevent and/or protect epithelial cells from deleterious effects of ultraviolet (UV) radiation. Eyes from 40 young-adult Sprague Dawley rats and cutaneous tissues from 36 adult nude mice were exposed to UVA/B lamp for 60 min, either alone or in the presence of murine NGF. Corneal, retinal, and cutaneous tissues were sampled/processed for morphological, immunohistochemical, and biomolecular analysis, and results were compared statistically. UV exposure affected both biochemical and molecular expression of NGF and trkA NGFR in corneal, retinal, and cutaneous tissues while UV exposure coupled to NGF treatment enhanced NGF and trkA NGFR expression as well as reduced cell death. Overall, the findings of this in vivo/ex vivo study show the NGF ability to reduce the potential UV damage. Although the mechanism underneath this effect needs further investigation, these observations prospect the development of a pharmacological NGF-based therapy devoted to maintain cell function when exposed to phototoxic UV radiation.

  14. Induction and repair of lethal and oncogenic lesions and their relationship to cytogenetic changes in UV-irradiated mouse 10T1/2 cells

    International Nuclear Information System (INIS)

    Chan, G.L.; Nagasawa, H.; Little, J.B.

    1979-01-01

    While bacterial system is valuable for the pragmatic purpose of screening potential environmental carcinogens, the fundamental difference between prokaryotes and mammalian cells warrant caution against the use of bacterial mutagenic mechanisms to explain the oncogenic process in mammalian cells. The 10 T1/2 cells exposed to UV light in the plateau phase and subcultured immediately to low density to assay for clonogenic survival were extremely resistant to the cytotoxic effect of UV light. Purely physical considerations such as the increased thickness of plateau phase cells and the increased cytoplasmic shielding of UV light from the nuclei were insufficient to account for this unusual resistance. The effect of caffeine on the repair processes in UV-irradiated mammalian cells appears to be exerted during the first DNA synthetic phase after the UV exposure. The daughter DNA synthesized on a UV-irradiated template is of reduced molecular weight. 10 T1/2 cells were exposed in the log phase of growth to UV light, and then they were cultured for the next 48 hours in the complete growth medium containing the specific concentration of caffeine. Parallel experiments were performed, in which cells were exposed for 48 hours to caffeine only with no prior exposure to UV light. It was found that caffeine did not potentiate the transformation by UV light. Caffeine alone induced sister chromatid exchange (SCE), whereas the caffeine given after UV light had no effect. The class of UV-induced lesions which induce SCE also leads to malignant transformation. (Yamashita, S.)

  15. Aggregate consumer exposure to UV filter ethylhexyl methoxycinnamate via personal care products.

    Science.gov (United States)

    Manová, Eva; von Goetz, Natalie; Hungerbuehler, Konrad

    2015-01-01

    Ultraviolet (UV) filters are substances designed to protect our skin from UV-induced damage and can be found in many categories of personal care products (PCPs). The potential endocrine-disrupting effects attributed to UV filter ethylhexyl methoxycinnamate (EHMC) are being debated. We evaluated the aggregate exposure of the Swiss-German population (N=1196; ages ≤1-97years) to EHMC via the use of PCPs; thus we provide the first comprehensive information about the current EHMC exposure sources and aggregate exposure levels. In our probabilistic modeling method performed at an individual level, PCP use data obtained by a postal questionnaire were linked to concentration data on EHMC gained from chemical analyses of PCPs used by the questionnaire respondents. The modeled median and 99.9th percentile of the internal aggregate exposure for the general population were 0.012 and 0.873mgday(-1)kg(-1) and 0.008 and 0.122mgday(-1)kg(-1) for the summer/autumn and winter/spring period, respectively. The major contributors to internal aggregate exposure were sunscreen products in summer/autumn (females: 64%; males: 85%; children aged ≤12years 93%). In winter/spring, lip care dominated for females (30%) and sunscreen for males (38%) and children aged ≤12years (50%). Overall, the internal aggregate exposure estimates for the studied population are shown to be below the Derived No Effect Level (DNEL) for EHMC i.e., the level of exposure above which humans should not be exposed; however, when an intense short-term exposure via sunscreen is accounted for during a sunbathing day, at the high-end percentiles (99.9th) the predicted aggregate exposure exceeds the DNEL for thyroid-disrupting effects such as for children aged ≤4years, who might be particularly susceptible to endocrine disrupting events. It is nevertheless critical to acknowledge that quantitative data on transdermal penetration of EHMC from PCPs are currently insufficient. Since long-term effects of endocrine

  16. Electrophysiological and growing aspects of ultraviolet (UV-C) radiation action

    International Nuclear Information System (INIS)

    Karcz, W.

    1992-01-01

    Effects of UV-C (254 nm) radiation on electrical parameters and growth processes in plant cells were studied. It was found in Nitellopsis obtusa cells the UV-C radiation caused transient depolarization of plasmalemma and tonoplast and simultaneous increase in electric conductance. These effects were partly reversible and the degree of the recovery depended on the duration of the exposure, temperature of the medium and area of the irradiation. Exposure of Nitellopsis obtusa cells with large potential difference between vacuole and external medium (more negative than - 140 mV) brought about the generation of an action potential, whose shape depended on the duration of irradiation. In the cells pretreated with IAA in the dark or exposed to visible light, the UV-C irradiation not only abolished the hyper polarization induced by IAA or visible light, but caused a further depolarization. Similar effects of IAA and UV-C on membrane potential were demonstrated in cells of Zea mays L. coleoptile segments. The hyper polarized state created by visible light in Sagittaria leaf cells was also fully suppressed by the radiation. The growth experiments were based on elongation growth of Zea mays L. coleoptile segments and simultaneously measured changes of pH of the incubation medium. It was shown that for high doses of irradiation (1170, 3900, and 5850 J m -2 ) UV-C inhibited elongation growth, whereas at 195 J m -2 stimulation of growth was observed. The administration of IAA (10 -5 M) and FC (10 -6 M) to the incubation medium of coleoptile segments partially abolished the inhibitory effect of UV-C. The pH of the incubation medium showed that the exposure of the segments to UV-C caused inhibition H + -extrusion (or stimulation of H + uptake). The presence of IAA (10 -5 M) or FC (10 -6 M) in the incubation medium of irradiated coleoptile segments promoted H + -extrusion to a level comparable with that produced by IAA or FC in non-irradiated coleoptile segments. It is suggested

  17. Effects of UV-C Light Exposure and Refrigeration on Phenolic and Antioxidant Profiles of Subtropical Fruits (Litchi, Longan, and Rambutan in Different Fruit Forms

    Directory of Open Access Journals (Sweden)

    Peilong Li

    2017-01-01

    Full Text Available The objectives of this study were to investigate how UV-C irradiation and refrigeration affect shelf-life and antioxidant level of litchi, longan, and rambutan. Three forms (whole, dehulled, and destoned of fresh fruits were treated by refrigeration and UV-C irradiations. After processing, deterioration rate, phenolics compounds, and antioxidant capacity were quantified. The deterioration rate was recorded as decay index. The results showed that both refrigeration and UV-C exposure extended the shelf-life of the fruits. The refrigeration enriched antioxidant levels of litchi but caused nutritional degradation in longan and rambutan; UV-C radiation enriched litchi antioxidant contents but was related to reduction of antioxidant capacity in longan and rambutan. Removing hulls and stones was associated with the decrease of antioxidants in litchi. The effects on antioxidant levels varied from fruit to fruit, resulting from hormesis phenomenon. The change of phytochemical levels was hypothesized as an accumulative process. The effects of fruit forms were not consistent in different fruits, which could be multifactorially influenced.

  18. The effect of solarradiation and UV photons on the CR-39 nuclear track detector

    International Nuclear Information System (INIS)

    Saad, A.F.

    2003-01-01

    The effects induced in the CR-39 polymer detector by total solar radiation (TSR) and UV photons were investigated. Thr exposure of detector samples to solar photons was carried out according to certain conditions. The TSR exposure period started in the middle of july and lasted unitel 12 th of september. 2000: the hottest months in zagazig, egypt. Another set of detector samples was exposed to UV photons from a UV lamp for different intervals. After UV exposure, these detectors were analysed with an FT-IR sepectrometer of jasco type 5300 in transmission mode. The FT-IR spectra does not show any considerable modifications due to UV irradiation in that detector. The effects of UV light were compared with those of solar radiation containing ultraviolet photons , on the registration properties of this polymer detector. Preliminaryresults revealed a proportionate increase in bluk etch rate of CR-39 detector with the increase of exposure time to the solar radiation. The results indicated that the CR-39 polymer detector can be used as a solar radiation dosimeter

  19. UV waveguides light fabricated in fluoropolymer CYTOP by femtosecond laser direct writing.

    Science.gov (United States)

    Hanada, Yasutaka; Sugioka, Koji; Midorikawa, Katsumi

    2010-01-18

    We have fabricated optical waveguides inside the UV-transparent polymer, CYTOP, by femtosecond laser direct writing for propagating UV light in biochip applications. Femtosecond laser irradiation is estimated to increase the refractive index of CYTOP by 1.7 x 10(-3) due to partial bond breaking in CYTOP. The waveguide in CYTOP has propagation losses of 0.49, 0.77, and 0.91 dB/cm at wavelengths of 632.8, 355, and 266 nm, respectively.

  20. Studies on the pathogenesis and survival of different culture forms of Listeria monocytogenes to pulsed UV-light irradiation after exposure to mild-food processing stresses.

    Science.gov (United States)

    Bradley, Derek; McNeil, Brian; Laffey, John G; Rowan, Neil J

    2012-06-01

    The effects of mild conventional food-processing conditions on Listeria monocytogenes survival to pulsed UV (PUV) irradiation and virulence-associated characteristics were investigated. Specifically, this study describes the inability of 10 strains representative of 3 different culture forms or morphotypes of L. monocytogenes to adapt to normally lethal levels of PUV-irradiation after exposure to sub-lethal concentrations of salt (7.5% (w/v) NaCl for 1 h), acid (pH 5.5 for 1 h), heating (48 °C for 1 h) or PUV (UV dose 0.08 μJ/cm(2)). Findings showed that the order of increasing sensitivity of L. monocytogenes of non-adapted and stressed morphotypes to low pH (pH 3.5 for 5 h, adjusted with lactic), high salt (17.5% w/v NaCl for 5 h), heating (60 °C for 1 h) and PUV-irradiation (100 pulses at 7.2 J and 12.8 J, equivalent to UV doses of 2.7 and 8.4 μJ/cm(2) respectively) was typical wild-type smooth (S/WT), atypical filamentous rough (FR) and atypical multiple-cell-chain (MCR) variants. Exposure of L. monocytogenes cells to sub-lethal acid, salt or heating conditions resulted in similar or increased susceptibility to PUV treatments. Only prior exposure to mild heat stressing significantly enhanced invasion of Caco-2 cells, whereas subjection of L. monocytogenes cells to combined sub-lethal salt, acid and heating conditions produced the greatest reduction in invasiveness. Implications of these findings are discussed. This constitutes the first study to show that pre-exposure to mild conventional food-processing stresses enhances sensitivity of different culture morphotypes of L. monocytogenes to PUV, which is growing in popularity as an alternative or complementary approach for decontamination in the food environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. U.V. repair in deep-sea bacteria

    International Nuclear Information System (INIS)

    Lutz, L.; Yayanos, A.A.

    1986-01-01

    Exposure of cells to light of less than 320 nanometers wavelengths may lead to lethal lesions and perhaps carcinogenesis. Many organisms have evolved mechanisms to repair U.V. light-induced damage. Organisms such as deep-sea bacteria are presumably never exposed to U.V. light and perhaps occasionally to visible from bioluminescence. Thus, the repair of U.V. damage in deep-sea bacterial DNA might be inefficient and repair by photoreactivation unlikely. The bacteria utilized in this investigation are temperature sensitive and barophilic. Four deep-sea isolates were chosen for this study: PE-36 from 3584 m, CNPT-3 from 5782 m, HS-34 from 5682 m, and MT-41 from 10,476 m, all are from the North Pacific ocean. The deep-sea extends from 1100 m to depths greater than 7000 m. It is a region of relatively uniform conditions. The temperature ranges from 5 to -1 0 C. There is no solar light in the deep-sea. Deep-sea bacteria are sensitive to U.V. light; in fact more sensitive than a variety of terrestrial and sea-surface bacteria. All four isolates demonstrate thymine dimer repair. Photoreactivation was observed in only MT-41. The other strains from shallower depths displayed no photoreactivation. The presence of DNA sequences homologous to the rec A, uvr A, B, and C and phr genes of E. coli have been examined by Southern hybridization techniques

  2. Relationship Between Landscape Character, UV Exposure, and Amphibian Decline

    Science.gov (United States)

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

    2001-12-01

    Widespread reports of amphibian declines have been considered a warning of large-scale environmental degradation, yet the reasons for these declines remain unclear. This study suggests that exposure to ultraviolet radiation may act as an environmental stressor that affects population breeding success or susceptibility to disease. Ultraviolet radiation is attenuated by dissolved and particulate compounds in water, which may be of either terrestrial or aquatic origin. UV attenuation by dissolved organic carbon (DOC) is primarily due to compounds in the fulvic acid fraction, which originate in soil environments. These terrestrially-derived fulvic acids are transported to during hydrologic flushing events such as snowmelt and episodic precipitation and play an important role in controlling UV exposure in surface waters. As part of a previously published project, amphibian surveys were conducted at seventeen sites in Rocky Mountain National Park both during, and subsequent to, a three-year drought (1988 - 1990). During this period, ten sites lost one amphibian species, while only one site gained a previously unreported species. One possible explanation for these localized species losses is increased exposure to UV radiation, mediated by reduced terrestrial DOC inputs during dry periods. Several subsequent years of water chemistry data showed that the sites with documented species losses were characterized by a range of DOC concentrations, but tended to have a greater proportion of terrestrial DOC than sites that did not undergo species loss. This suggests that terrestrial inputs exert a strong control on DOC concentrations that may influence species success. We used physical environmental factors to develop a classification scheme for these sites. There are many physical factors that can influence terrestrial DOC inputs, including landscape position, geomorphology, soil type, and watershed vegetation. In addition, we considered the possible effects on internal aquatic

  3. Application of 265-nm UVC LED Lighting to Sterilization of Typical Gram Negative and Positive Bacteria

    Science.gov (United States)

    Lee, Yong Wook; Yoon, Hyung Do; Park, Jae-Hyoun; Ryu, Uh-Chan

    2018-05-01

    UV LED lightings have been displacing conventional UV lamps due to their high efficiency, long lifetime, etc. A sterilizing lighting was prepared by assembling a UV LED module composed of 265-nm UVC LEDs and a silica lens array with a driver module comprised of a driver IC controlling pulse width modulation and constant current. The silica lens array was designed and fabricated to focus UV beam and simultaneously to give a uniform light distribution over specimens. Then pasteurizing effect of the lighting was analyzed for four kinds of bacteria and one yeast which are dangerous to people with low immunity. Sterilizing tests on these germs were carried out at the both exposure distances of 10 and 100 mm for various exposure durations up to 600 s.

  4. Removal of gaseous toluene by the combination of photocatalytic oxidation under complex light irradiation of UV and visible light and biological process

    International Nuclear Information System (INIS)

    Wei Zaishan; Sun Jianliang; Xie Zhirong; Liang Mingyan; Chen Shangzhi

    2010-01-01

    Photocatalysis is a promising technology for treatment of gaseous waste; its disadvantages, however, include causing secondary pollution. Biofiltration has been known as an efficient technology for treatment volatile organic compounds (VOCs) at low cost of maintenance, and produces harmless by-products; its disadvantages, include large volume of bioreactor and slow adaptation to fluctuating concentrations in waste gas. A bench scale system integrated with a photocatalytic oxidation and a biofilter unit for the treatment of gases containing toluene was investigated. The integrated system can effectively oxidize toluene with high removal efficiency. The photocatalytic activity of N-TiO 2 /zeolite was evaluated by the decomposition of toluene in air under UV and visible light (VL) illumination. The N-TiO 2 /zeolite has more photocatalytic activity under complex light irradiation of UV and visible light for toluene removal than that of pure TiO 2 /zeolite under UV or visible light irradiation. N-TiO 2 /zeolite was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectrum analysis (XPS), Fourier transform infrared spectroscopy (FT-IR), and as-obtained products were identified by means of gas chromatography/mass spectrometry (GC/MS). Results revealed that the photocatalyst was porous and was high photoactive for mineralizing toluene. The high activity can be attributed to the results of the synergetic effects of strong UV and visible light absorption, surface hydroxyl groups. The photocatalytic degradation reaction of toluene with the N-TiO 2 /zeolite follows Langmuir-Hinshelwood kinetics. Toluene biodegradation rate matches enzymatic oxidation kinetics model.

  5. UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii

    Science.gov (United States)

    Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B.; Niyogi, Krishna K.; Goldschmidt-Clermont, Michel

    2016-01-01

    Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast. PMID:27930292

  6. UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B; Niyogi, Krishna K; Ulm, Roman; Goldschmidt-Clermont, Michel

    2016-12-20

    Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast.

  7. UV-B affects photosynthesis, ROS production and motility of the freshwater flagellate, Euglena agilis Carter

    Energy Technology Data Exchange (ETDEWEB)

    Kottuparambil, Sreejith [Institute of Green Environmental Research Center, University of Incheon, Incheon, 406 840 (Korea, Republic of); Shin, Woongghi [Department of Biology, Chungnam University, Daejeon, 306 764 (Korea, Republic of); Brown, Murray T. [School of Marine Science and Engineering, Plymouth University, Drake Circus, Plymouth PL4 8AA (United Kingdom); Han, Taejun, E-mail: hanalgae@hanmail.net [Institute of Green Environmental Research Center, University of Incheon, Incheon, 406 840 (Korea, Republic of); Department of Marine Science, University of Incheon, Incheon, 406 840 (Korea, Republic of)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We proposed a hypothesis for the UV-B protective/adaptive mechanism in Euglena agilis. After moderate levels of UV-B radiation, ROS plays a signaling role to shut down photosynthetic system for protection against harmful UV radiation. Black-Right-Pointing-Pointer E. agilis exposed to excessive UV appears to become animal-like, investing all its stored energy into movement rather than into sustaining its photosynthetic machinery. Black-Right-Pointing-Pointer This adaptation allows E. agilis to avoid harmful UV and seek a safe place where the organism may regain its photosynthetic capacity for survival. - Abstract: The effects of ultraviolet B (UV-B; 295-320 nm) radiation on certain vital physiological (photosynthesis), biochemical (production of reactive oxygen species - ROS) and behavioral (motility and orientation) characteristics were investigated in the unicellular photoautotroph, Euglena agilis Carter. The photosynthetic performance of E. agilis was recorded after exposure of between 15 and 60 min followed by a period of recovery lasting 6-24 h under dim light (5-10 {mu}mol photons m{sup -2} s{sup -1}). The maximum quantum yield of PS II (F{sub v}/F{sub m}) was reduced to 65% and 14% of initial values immediately following 15 and 30 min UV-B exposure, but recovered to 100 and 86% of the initials, respectively. Values of rETR{sub max} in E. agilis exposed to 15 min UV-B were similar to those of the initials, but a 30 min UV exposure resulted in 75% reduction of rETR{sub max} with only a 43% recovery as compared with the initial after 24 h recovery. After a 60 min UV-B exposure, there were no Chl a fluorescence signals, and hence no F{sub v}/F{sub m} or rETR{sub max}. A UV dose-dependent increase in DCFH-DA fluorescence was found in E. agilis cells, reflecting an increase in ROS production. After exposures to UV-B for between 15 and 60 min, the percentages of motile cells in the population decreased to 76, 39 and 15

  8. Inactivation of bacteria via photosensitization of vitamin K3 by UV-A light.

    Science.gov (United States)

    Xu, Fei; Vostal, Jaroslav G

    2014-09-01

    This study investigated inactivation of bacteria with ultraviolet light A irradiation in combination with vitamin K3 as a photosensitizer. Six bacteria including Bacillus cereus, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, and Escherichia coli suspended in vitamin K3 aqueous solution were exposed to ultraviolet light A. Five of six bacteria, with the exception of Pseudomonas aeruginosa, were reduced by eight logs with 1600 μM of vitamin K3 and 5.8 J cm(-2) UV-A irradiation. Pseudomonas aeruginosa was reduced by four logs under these conditions. Reactive oxygen species including singlet oxygen, hydroxyl radical and superoxide anion radical were generated in vitamin K3 aqueous solution under UV-A irradiation. These results suggest that vitamin K3 and UV-A irradiation may be effective for bacterial inactivation in environmental and medical applications. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  9. Effect of UV irradiation on the apoptosis and necrosis of Jurkat cells using UV LEDs

    Science.gov (United States)

    Inada, Shunko A.; Amano, Hiroshi; Akasaki, Isamu; Morita, Akimichi; Kobayashi, Keiko

    2009-02-01

    Phototherapy is a very effective method for treating most of the incurable skin diseases. A fluorescent light bulb is used as a conventional UV light source for this type of therapy. However, infrared radiation from the light source sometimes causes serious problems on patient's health. In addition, the normal part of the skin is irradiated when a large fluorescent light bulb is used. Moreover, a conventional UV irradiation system is heavy and has a short lifetime and a high electrical power consumption. Therefore, a new UV light source for solving the problems of phototherapy is required. To realize low-power-consumption, lightweight and long-lifetime systems, group III nitride-based UV-A1 light-emitting diodes (LEDs) were investigated. We examined the UV LED irradiation of Jurkat cell, which is a tumor cell and more sensitive to UV light than a healthy cell. The numbers of apoptotic and necrotic cells were confirmed to be the same using a UV LED and a conventional lamp system. The UV LED showed the possibility of realizing a new UV light source for phototherapy.

  10. Abnormal environmental light exposure in the intensive care environment.

    Science.gov (United States)

    Fan, Emily P; Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C; Maas, Matthew B

    2017-08-01

    We sought to characterize ambient light exposure in the intensive care unit (ICU) environment to identify patterns of light exposure relevant to circadian regulation. A light monitor was affixed to subjects' bed at eye level in a modern intensive care unit and continuously recorded illuminescence for at least 24h per subject. Blood was sampled hourly and measured for plasma melatonin. Subjects underwent hourly vital sign and bedside neurologic assessments. Care protocols and the ICU environment were not modified for the study. A total of 67,324 30-second epochs of light data were collected from 17 subjects. Light intensity peaked in the late morning, median 64.1 (interquartile range 19.7-138.7) lux. The 75th percentile of light intensity exceeded 100lx only between 9AM and noon, and never exceeded 150lx. There was no correlation between melatonin amplitude and daytime, nighttime or total light exposure (Spearman's correlation coefficients all 0.5). Patients' environmental light exposure in the intensive care unit is consistently low and follows a diurnal pattern. No effect of nighttime light exposure was observed on melatonin secretion. Inadequate daytime light exposure in the ICU may contribute to abnormal circadian rhythms. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Meckes, M.C.

    1982-01-01

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

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

    OpenAIRE

    Arrage, Andrew Anthony

    1991-01-01

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

  13. Adaptation mechanisms of Escherichia Coli to the ultraviolet light I. Isolation of mutants resistant to ultraviolet light

    International Nuclear Information System (INIS)

    Alcantara D, D.

    1995-09-01

    The objective of this work is to study the adaptation mechanisms of Escherichia coli to the ultraviolet light of 254 nm (W), a component of the solar light that induces a variety of damages in the DNA of the cells exposed, which should be eliminated in order to avoid its lethal and mutagenic effects. Inside this first report, the results obtained about the resistance to UV radiation of 5 independent populations of Escherichia coli, which were subjected in parallel form to 80 successive exposures of UV light with inserted periods of growth are reported. (Author)

  14. Occupational UV-Exposure is a Major Risk Factor for Basal Cell Carcinoma: Results of the Population-Based Case-Control Study FB-181.

    Science.gov (United States)

    Schmitt, Jochen; Haufe, Eva; Trautmann, Freya; Schulze, Hans-Joachim; Elsner, Peter; Drexler, Hans; Bauer, Andrea; Letzel, Stephan; John, Swen Malte; Fartasch, Manigé; Brüning, Thomas; Seidler, Andreas; Dugas-Breit, Susanne; Gina, Michal; Weistenhöfer, Wobbeke; Bachmann, Klaus; Bruhn, Ilka; Lang, Berenice Mareen; Bonness, Sonja; Allam, Jean Pierre; Grobe, William; Stange, Thoralf; Westerhausen, Stephan; Knuschke, Peter; Wittlich, Marc; Diepgen, Thomas Ludwig

    2018-01-01

    The aim of this study was to investigate the role of occupational and nonoccupational ultraviolet (UV)-exposure concerning the development of basal cell carcinoma (BCC). We undertook a population-based multicenter case-control study. Patients with first incident BCC (n = 836) were propensity score matched by age and sex to controls without skin cancer (n = 836). Sociodemographic characteristics, clinical characteristics, and lifetime UV-exposure were assessed by trained investigators. The differential estimation of occupational and nonoccupational UV-exposure dosages was based on validated instruments and established reference values. Associations were assessed using multivariable-adjusted conditional logistic regression models. Individuals with high levels of occupational UV-exposure were at significantly increased BCC-risk compared with individuals with low [odds ratio (OR) 1.84; 95% confidence interval (95% CI) 1.19 to 2.83 and moderate (OR 1.97; 95% CI 1.20 to 3.22) occupational UV-exposure. Nonoccupational UV-exposure was not independently associated with BCC. Skin cancer prevention strategies should be expanded to the occupational setting.

  15. Phosphors for near UV-Emitting LED's for Efficacious Generation of White Light

    Energy Technology Data Exchange (ETDEWEB)

    McKittrick, Joanna [Univ. of California, San Diego, CA (United States)

    2013-09-30

    1) We studied phosphors for near-UV (nUV) LED application as an alternative to blue LEDs currently being used in SSL systems. We have shown that nUV light sources could be very efficient at high current and will have significantly less binning at both the chip and phosphor levels. We identified phosphor blends that could yield 4100K lamps with a CRI of approximately 80 and LPWnUV,opt equal to 179 for the best performing phosphor blend. Considering the fact that the lamps were not optimized for light coupling, the results are quite impressive. The main bottleneck is an optimum blue phosphor with a peak near 440 nm with a full width half maximum of about 25 nm and a quantum efficiency of >95%. Unfortunately, that may be a very difficult task when we want to excite a phosphor at ~400 nm with a very small margin for Stokes shift. Another way is to have all the phosphors in the blend having the excitation peak at 400 nm or slightly shorter wavelength. This could lead to a white light source with no body color and optimum efficacy due to no self-absorption effects by phosphors in the blend. This is even harder than finding an ideal blue phosphor, but not necessarily impossible. 2) With the phosphor blends identified, light sources using nUV LEDs at high current could be designed with comparable efficacy to those using blue LEDs. It will allow us to design light sources with multiple wattages using the same chips and phosphor blends simply by varying the input current. In the case of blue LEDs, this is not currently possible because varying the current will lower the efficacy at high current and alter the color point. With improvement of phosphor blends, control over CRI could improve. Less binning at the chip level and also at the phosphor blend level could reduce the cost of SSL light sources. 3) This study provided a deeper understanding of phosphor characteristics needed for LEDs in general and nUV LEDs in particular. Two students received Ph.D. degrees and three

  16. Photocatalytic degradation of p,p'-DDT under UV and visible light using interstitial N-doped TiO₂.

    Science.gov (United States)

    Ananpattarachai, Jirapat; Kajitvichyanukul, Puangrat

    2015-01-01

    1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (or p,p'-DDT) is one of the most persistent pesticides. It is resistant to breakdown in nature and cause the water contamination problem. In this work, a major objective was to demonstrate the application of N-doped TiO2 in degradation and mineralization of the p,p'-DDT under UV and visible light in aqueous solution. The N-doped TiO2 nanopowders were prepared by a simple modified sol-gel procedure using diethanolamine (DEA) as a nitrogen source. The catalyst characteristics were investigated using XRD, SEM, TEM, and XPS. The adsorption and photocatalytic oxidation of p,p'-DDT using the synthesized N-doped TiO2 under UV and visible light were conducted in a batch photocatalytic experiment. The kinetics and p,p'-DDT degradation performance of the N-doped TiO2 were evaluated. Results show that the N-doped TiO2 can degrade p,p'-DDT effectively under both UV and visible lights. The rate constant of the p,p'-DDT degradation under UV light was only 0.0121 min(-1), whereas the rate constant of the p,p'-DDT degradation under visible light was 0.1282 min(-1). Under visible light, the 100% degradation of p,p'-DDT were obtained from N-doped TiO2 catalyst. The reaction rate of p,p'-DDT degradation using N-doped TiO2 under visible light was sixfold higher than that under UV light. According to Langmuir-Hinshelwood model, the adsorption equilibrium constant (K) for the N-doped TiO2 under visible light was 0.03078 L mg(-1), and the apparent reaction rate constant (k) was 1.3941 mg L(-1)-min. Major intermediates detected during the p,p'-DDT degradation were p,p'-DDE, o,p'-DDE, p,p'-DDD and p,p'-DDD. Results from this work can be applied further for the breakdown of p,p'-DDT molecule in the real contaminated water using this technology.

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

    International Nuclear Information System (INIS)

    Beblo, K.; Wirth, R.; Huber, H.; Douki, T.; Schmalz, G.; Rachel, R.

    2011-01-01

    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)

  18. UV-visible light-activated Ag-decorated, monodisperse TiO2 aggregates for treatment of the pharmaceutical oxytetracycline.

    Science.gov (United States)

    Han, Changseok; Likodimos, Vlassis; Khan, Javed Ali; Nadagouda, Mallikarjuna N; Andersen, Joel; Falaras, Polycarpos; Rosales-Lombardi, Pablo; Dionysiou, Dionysios D

    2014-10-01

    Noble metal Ag-decorated, monodisperse TiO2 aggregates were successfully synthesized by an ionic strength-assisted, simple sol-gel method and were used for the photocatalytic degradation of the antibiotic oxytetracycline (OTC) under both UV and visible light (UV-visible light) irradiation. The synthesized samples were characterized by X-ray diffraction analysis (XRD); UV-vis diffuse reflectance spectroscopy; environmental scanning electron microscopy (ESEM); transmission electron microscopy (TEM); high-resolution TEM (HR-TEM); micro-Raman, energy-dispersive X-ray spectroscopy (EDS); and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the uniformity of TiO2 aggregates was finely tuned by the sol-gel method, and Ag was well decorated on the monodisperse TiO2 aggregates. The absorption of the samples in the visible light region increased with increasing Ag loading that was proportional to the amount of Ag precursor added in the solution over the tested concentration range. The Brunauer, Emmett, and Teller (The BET) surface area slightly decreased with increasing Ag loading on the TiO2 aggregates. Ag-decorated TiO2 samples demonstrated enhanced photocatalytic activity for the degradation of OTC under UV-visible light illumination compared to that of pure TiO2. The sample containing 1.9 wt% Ag showed the highest photocatalytic activity for the degradation of OTC under both UV-visible light and visible light illumination. During the experiments, the detected Ag leaching for the best TiO2-Ag photocatalyst was much lower than the National Secondary Drinking Water Regulation for Ag limit (0.1 mg L(-1)) issued by the US Environmental Protection Agency.

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  20. Lens of controllable optical field with thin film metallic glasses for UV-LEDs.

    Science.gov (United States)

    Pan, C T; Chen, Y C; Lin, Po-Hung; Hsieh, C C; Hsu, F T; Lin, Po-Hsun; Chang, C M; Hsu, J H; Huang, J C

    2014-06-16

    In the exposure process of photolithography, a free-form lens is designed and fabricated for UV-LED (Ultraviolet Light-Emitting Diode). Thin film metallic glasses (TFMG) are adopted as UV reflection layers to enhance the irradiance and uniformity. The Polydimethylsiloxane (PDMS) with high transmittance is used as the lens material. The 3-D fast printing is attempted to make the mold of the lens. The results show that the average irradiance can be enhanced by 6.5~6.7%, and high uniformity of 85~86% can be obtained. Exposure on commercial thick photoresist using this UV-LED system shows 3~5% dimensional deviation, lower than the 6~8% deviation for commercial mercury lamp system. This current system shows promising potential to replace the conventional mercury exposure systems.

  1. Quality assessment of solar UV irradiance measured with array spectroradiometers

    Science.gov (United States)

    Egli, Luca; Gröbner, Julian; Hülsen, Gregor; Bachmann, Luciano; Blumthaler, Mario; Dubard, Jimmy; Khazova, Marina; Kift, Richard; Hoogendijk, Kees; Serrano, Antonio; Smedley, Andrew; Vilaplana, José-Manuel

    2016-04-01

    The reliable quantification of ultraviolet (UV) radiation at the earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers (ASRMs) are small, light, robust and cost-effective instruments, and are increasingly used for spectral irradiance measurements. Within the European EMRP ENV03 project "Solar UV", new devices, guidelines and characterization methods have been developed to improve solar UV measurements with ASRMs, and support to the end user community has been provided. In order to assess the quality of 14 end user ASRMs, a solar UV intercomparison was held on the measurement platform of the World Radiation Center (PMOD/WRC) in Davos, Switzerland, from 10 to 17 July 2014. The results of the blind intercomparison revealed that ASRMs, currently used for solar UV measurements, show a large variation in the quality of their solar UV measurements. Most of the instruments overestimate the erythema-weighted UV index - in particular at large solar zenith angles - due to stray light contribution in the UV-B range. The spectral analysis of global solar UV irradiance further supported the finding that the uncertainties in the UV-B range are very large due to stray light contribution in this wavelength range. In summary, the UV index may be detected by some commercially available ASRMs within 5 % compared to the world reference spectroradiometer, if well characterized and calibrated, but only for a limited range of solar zenith angles. Generally, the tested instruments are not yet suitable for solar UV measurements for the entire range between 290 and 400 nm under all atmospheric conditions.

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

    Science.gov (United States)

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

    2008-12-01

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

  3. UV-VUV laser induced phenomena in SiO2 glass

    International Nuclear Information System (INIS)

    Kajihara, Koichi; Ikuta, Yoshiaki; Oto, Masanori; Hirano, Masahiro; Skuja, Linards; Hosono, Hideo

    2004-01-01

    Creation and annihilation of point defects were studied for SiO 2 glass exposed to ultraviolet (UV) and vacuum UV (VUV) lights to improve transparency and radiation toughness of SiO 2 glass to UV-VUV laser light. Topologically disordered structure of SiO 2 glass featured by the distribution of Si-O-Si angle is a critical factor degrading transmittance near the fundamental absorption edge. Doping with terminal functional groups enhances the structural relaxation and reduces the number of strained Si-O-Si bonds by breaking up the glass network without creating the color centers. Transmittance and laser toughness of SiO 2 glass for F 2 laser is greatly improved in fluorine-doped SiO 2 glass, often referred as 'modified silica glass'. Interstitial hydrogenous species are mobile and reactive at ambient temperature, and play an important role in photochemical reactions induced by exposure to UV-VUV laser light. They terminate the dangling-bond type color centers, while enhancing the formation of the oxygen vacancies. These findings are utilized to develop a deep-UV optical fiber transmitting ArF laser photons with low radiation damage

  4. Induced recovery from near- and far-UV damage in cultured marsupial cells

    International Nuclear Information System (INIS)

    Hoy, D.A.

    1982-01-01

    Colony-forming ability of cultured rat kangaroo cells (Ptk-2) decreases with increasing exposure to light from a daylight fluorescent lamp. After reaching a minimum, survival increases with further exposure, forming a V-shaped survival curve. This increase is inhibited by low concentrations of the protein synthesis inhibitor cycloheximide. The resulting V-shaped survival curve was characterized with respect to several experimental parameters; it appears to be due to an induced repair system dependent on protein synthesis. These results suggest that induced repair, dependent on protein synthesis, in response to fluorescent, near UV, and far UV light damage, is a major repair pathway in Ptk-2 cells, and provides a characterizable system that can elucidate induced repair mechanisms in other mammalian cells

  5. Influence of UV irradiation on the blue and red light photoinduced processes in azobenzene polyesters

    DEFF Research Database (Denmark)

    Rodríguez, F.J.; Sánchez, C.; Villacampa, B.

    2004-01-01

    light that yields the films into the isotropic state at room temperature (RT) was compared with the quenching from temperatures above the isotropic transition temperature Ti. UV–visible spectra of the thermally quenched films show the presence of aggregates when measured at RT. We have found that UV......Birefringence induced in a series of liquid crystalline side-chain azobenzene polyesters with different substituent groups was investigated under irradiation with 488 and 633 nm linearly polarized lights. Two different initial conditions have been used: the effect of a previous irradiation with UV...

  6. Applicability of light sources and the inner filter effect in UV/acetylacetone and UV/H{sub 2}O{sub 2} processes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Bingdang; Yang, Minghui [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023 (China); Yin, Ran [Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Zhang, Shujuan, E-mail: sjzhang@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023 (China)

    2017-08-05

    Highlights: • Acetylacetone (AA) could directly use solar irradiation to decolorize dyes. • AA had a wider applicability than H{sub 2}O{sub 2} to a variety of light sources. • The photonic efficiency in the UV/AA process was target-dependent. • An accurate calculation approach for the inner filter effect was developed. - Abstract: Light source is a crucial factor in the application of a photochemical process, which determines the energy efficiency. The performances of acetylacetone (AA) in conversion of aqueous contaminants under irradiation with a low-pressure mercury lamp, a medium-pressure mercury lamp, a xenon lamp, and natural sunlight were investigated and compared with those of H{sub 2}O{sub 2} as reference. In all cases, AA was superior to H{sub 2}O{sub 2} in the degradation of Acid Orange 7. Using combinations of the different light sources with various cut-off and band-pass filters, the spectra responses of the absorbed photons in the UV/AA and UV/H{sub 2}O{sub 2} processes were determined for two colored and two colorless compounds. The photonic efficiency (φ) of the two photochemical processes was found to be target-dependent. A calculation approach for the inner filter effect was developed by taking the obtained φ into account, which provides a more accurate indication of the reaction mechanisms.

  7. Can narrow-bandwidth light from UV-A to green alter secondary plant metabolism and increase Brassica plant defenses against aphids?

    Science.gov (United States)

    Neugart, Susanne; Schreiner, Monika; Wu, Sasa; Poehling, Hans-Michael

    2017-01-01

    Light of different wavelengths is essential for plant growth and development. Short-wavelength radiation such as UV can shift the composition of flavonoids, glucosinolates, and other plant metabolites responsible for enhanced defense against certain herbivorous insects. The intensity of light-induced, metabolite-based resistance is plant- and insect species-specific and depends on herbivore feeding guild and specialization. The increasing use of light-emitting diodes (LEDs) in horticultural plant production systems in protected environments enables the creation of tailor-made light scenarios for improved plant cultivation and induced defense against herbivorous insects. In this study, broccoli (Brassica oleracea var. italica) plants were grown in a climate chamber under broad spectra photosynthetic active radiation (PAR) and were additionally treated with the following narrow-bandwidth light generated with LEDs: UV-A (365 nm), violet (420 nm), blue (470 nm), or green (515 nm). We determined the influence of narrow-bandwidth light on broccoli plant growth, secondary plant metabolism (flavonol glycosides and glucosinolates), and plant-mediated light effects on the performance and behavior of the specialized cabbage aphid Brevicoryne brassicae. Green light increased plant height more than UV-A, violet, or blue LED treatments. Among flavonol glycosides, specific quercetin and kaempferol glycosides were increased under violet light. The concentration of 3-indolylmethyl glucosinolate in plants was increased by UV-A treatment. B. brassicae performance was not influenced by the different light qualities, but in host-choice tests, B. brassicae preferred previously blue-illuminated plants (but not UV-A-, violet-, or green-illuminated plants) over control plants. PMID:29190278

  8. Can narrow-bandwidth light from UV-A to green alter secondary plant metabolism and increase Brassica plant defenses against aphids?

    Directory of Open Access Journals (Sweden)

    Ole Rechner

    Full Text Available Light of different wavelengths is essential for plant growth and development. Short-wavelength radiation such as UV can shift the composition of flavonoids, glucosinolates, and other plant metabolites responsible for enhanced defense against certain herbivorous insects. The intensity of light-induced, metabolite-based resistance is plant- and insect species-specific and depends on herbivore feeding guild and specialization. The increasing use of light-emitting diodes (LEDs in horticultural plant production systems in protected environments enables the creation of tailor-made light scenarios for improved plant cultivation and induced defense against herbivorous insects. In this study, broccoli (Brassica oleracea var. italica plants were grown in a climate chamber under broad spectra photosynthetic active radiation (PAR and were additionally treated with the following narrow-bandwidth light generated with LEDs: UV-A (365 nm, violet (420 nm, blue (470 nm, or green (515 nm. We determined the influence of narrow-bandwidth light on broccoli plant growth, secondary plant metabolism (flavonol glycosides and glucosinolates, and plant-mediated light effects on the performance and behavior of the specialized cabbage aphid Brevicoryne brassicae. Green light increased plant height more than UV-A, violet, or blue LED treatments. Among flavonol glycosides, specific quercetin and kaempferol glycosides were increased under violet light. The concentration of 3-indolylmethyl glucosinolate in plants was increased by UV-A treatment. B. brassicae performance was not influenced by the different light qualities, but in host-choice tests, B. brassicae preferred previously blue-illuminated plants (but not UV-A-, violet-, or green-illuminated plants over control plants.

  9. Induction of anthocyanin formation and of enzymes related to its biosynthesis by UV light in cell cultures of Haplopappus gracilis

    International Nuclear Information System (INIS)

    Wellmann, E.; Hrazdina, G.; Grisebach, H.

    1976-01-01

    Only UV light below 345 nm stimulates anthocyanin formation in dark grown cell suspension cultures of Haplopappus gracilis. A linear relationship between UV dose and flavonoid accumulation, as found previously with parsley cell cultures was not observed with the H.gracilis cells. Only continuous irradiation with high doses of UV was effective. Drastic increases in the activities of the enzymes phenylalanine ammonia-lyase, chalcone isomerase and flavanone synthase were observed under continuous UV light. The increase in enzyme activities paralleled anthocyanin formation. (author)

  10. Marginal eyespots on butterfly wings deflect bird attacks under low light intensities with UV wavelengths.

    Directory of Open Access Journals (Sweden)

    Martin Olofsson

    2010-05-01

    Full Text Available Predators preferentially attack vital body parts to avoid prey escape. Consequently, prey adaptations that make predators attack less crucial body parts are expected to evolve. Marginal eyespots on butterfly wings have long been thought to have this deflective, but hitherto undemonstrated function.Here we report that a butterfly, Lopinga achine, with broad-spectrum reflective white scales in its marginal eyespot pupils deceives a generalist avian predator, the blue tit, to attack the marginal eyespots, but only under particular conditions-in our experiments, low light intensities with a prominent UV component. Under high light intensity conditions with a similar UV component, and at low light intensities without UV, blue tits directed attacks towards the butterfly head.In nature, birds typically forage intensively at early dawn, when the light environment shifts to shorter wavelengths, and the contrast between the eyespot pupils and the background increases. Among butterflies, deflecting attacks is likely to be particularly important at dawn when low ambient temperatures make escape by flight impossible, and when insectivorous birds typically initiate another day's search for food. Our finding that the deflective function of eyespots is highly dependent on the ambient light environment helps explain why previous attempts have provided little support for the deflective role of marginal eyespots, and we hypothesize that the mechanism that we have discovered in our experiments in a laboratory setting may function also in nature when birds forage on resting butterflies under low light intensities.

  11. Marginal eyespots on butterfly wings deflect bird attacks under low light intensities with UV wavelengths.

    Science.gov (United States)

    Olofsson, Martin; Vallin, Adrian; Jakobsson, Sven; Wiklund, Christer

    2010-05-24

    Predators preferentially attack vital body parts to avoid prey escape. Consequently, prey adaptations that make predators attack less crucial body parts are expected to evolve. Marginal eyespots on butterfly wings have long been thought to have this deflective, but hitherto undemonstrated function. Here we report that a butterfly, Lopinga achine, with broad-spectrum reflective white scales in its marginal eyespot pupils deceives a generalist avian predator, the blue tit, to attack the marginal eyespots, but only under particular conditions-in our experiments, low light intensities with a prominent UV component. Under high light intensity conditions with a similar UV component, and at low light intensities without UV, blue tits directed attacks towards the butterfly head. In nature, birds typically forage intensively at early dawn, when the light environment shifts to shorter wavelengths, and the contrast between the eyespot pupils and the background increases. Among butterflies, deflecting attacks is likely to be particularly important at dawn when low ambient temperatures make escape by flight impossible, and when insectivorous birds typically initiate another day's search for food. Our finding that the deflective function of eyespots is highly dependent on the ambient light environment helps explain why previous attempts have provided little support for the deflective role of marginal eyespots, and we hypothesize that the mechanism that we have discovered in our experiments in a laboratory setting may function also in nature when birds forage on resting butterflies under low light intensities.

  12. UV-vis light transmittance through tinted contact lenses and the effect of color on values.

    Science.gov (United States)

    Osuagwu, Uchechukwu L; Ogbuehi, Kelechi C

    2014-06-01

    To assess the transmittance, in the 200-700nm electromagnetic radiation spectrum, by popularly used tinted soft contact lenses (CLs). The spectra transmittances of ultraviolet (UV)-blocking (I Day Acuvue Define, Freshlook ONE DAY) and non-UV-blocking (Durasoft 3, Tutti, and NeoCosmo) tinted soft CLs were tested. The transmittance of each lens, including nine different colors of Freshlook CL was recorded on spectrophotometer, and the data used to also calculate a UV protection factor (PF) for each lens brand tested, with a higher value indicating a higher level of protection. The UV-blocking CLs significantly reduced UVC, UVB & UVA transmission and thereby meet the American National Standards Institution standard for class 2 UV blockers: a maximum of 30% transmittance of UVA and 5% transmittance of UVB wavelengths. In contrast, the Durasoft 3, Tutti, and NeoCosmo CLs demonstrated negligible UV-blockage. The Acuvue Define CL offered the greatest protection from UVC (PF=69) and UVB (PF=55), but with only 35% luminous transmittance, while the Freshlook CL (especially gemstone green) offered the best protection from UVA (PF=24) and showed about 55% translucency. Overall, the UV-blocking CLs performed equally well across the UV spectrum. Different colors of Freshlook CL transmitted statistically and clinically significantly different amounts of visible light but similar amounts of UVR. Freshlook and Acuvue Define CLs which are designated as UV-blockers significantly reduced UVR transmission to safe levels whereas Tutti, NeoCosmo and Durasoft 3 did not. Transmission within the Freshlook CL family was more dependent on color in the visible light spectrum, but not in the UV-spectrum, where the gemstone green performing best among the tested colors. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  13. Stability of UV exposed RR-P3BT films by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Diware, Mangesh S.; Byun, J. S.; Hwang, S. Y.; Kim, T. J.; Kim, Y. D.

    2013-01-01

    Stability of regioregular poly(3-butylthiophene) (RR-P3BT) films under irradiation of ultra-violet (UV) light has been studied by spectroscopic ellipsometry at room temperature. Consistent decrease in dielectric function with UV exposure time showed the degree of degradation of polymer. This work suggests that, protective methods are mandatory to use this kind of material in optical devices.

  14. Properties of the Visible Light Phototaxis and UV Avoidance Behaviors in the Larval Zebrafish.

    Science.gov (United States)

    Guggiana-Nilo, Drago A; Engert, Florian

    2016-01-01

    For many organisms, color is an essential source of information from visual scenes. The larval zebrafish has the potential to be a model for the study of this topic, given its tetrachromatic retina and high dependence on vision. In this study we took a step toward understanding how the larval zebrafish might use color sensing. To this end, we used a projector-based paradigm to force a choice of a color stimulus at every turn of the larva. The stimuli used spanned most of the larval spectral range, including activation of its Ultraviolet (UV) cone, which has not been described behaviorally before. We found that zebrafish larvae swim toward visible wavelengths (>400 nm) when choosing between them and darkness, as has been reported with white light. However, when presented with UV light and darkness zebrafish show an intensity dependent avoidance behavior. This UV avoidance does not interact cooperatively with phototaxis toward longer wavelengths, but can compete against it in an intensity dependent manner. Finally, we show that the avoidance behavior depends on the presence of eyes with functional UV cones. These findings open future avenues for studying the neural circuits that underlie color sensing in the larval zebrafish.

  15. Redistribution of melanosomal complexes within keratinocytes following UV-A irradiation

    International Nuclear Information System (INIS)

    Lavker, R.M.; Kaidbey, K.H.

    1982-01-01

    In contrast to other ultraviolet (UV) wavelengths, UV-A can induce long-term or 'true' pigmentation rapidly with little or no latency. The response cannot be clearly separated from immediate pigment darkening and is too rapid in onset to be explained by neomelanogenesis. In order to investigate possible mechanisms for this phenomenon, UV-irradiated skin was examined microscopically and ultrastructurally 18 h postirradiation. Specimens from skin sites tanned by exposure to melanogenic doses of UV-A showed a paradoxical reduction in the degree of basal melanization by light microscopy compared to unirradiated skin. Ultrastructurally, there was migration and dispersion of packaged melanosomes within keratinocytes from their normal, aggregated location around the nucleus towards the periphery of the cell. These changes were not observed in specimens exposed to melanogenic doses of UV-B. We propose that UV-A wavelengths can selectively cause redistribution of melanin-laden organelles within human keratinocytes in vivo and that this phenomenon accounts for the visually observed hyperpigmentation that develops soon after single exposures to these wavelengths. Dispersion of melanosomal complexes may be another mechanism by which UV-radiation (UVR) can induce tanning in human skin. (orig.)

  16. Redistribution of melanosomal complexes within keratinocytes following UV-A irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lavker, R.M.; Kaidbey, K.H.

    1982-03-01

    In contrast to other ultraviolet (UV) wavelengths, UV-A can induce long-term or 'true' pigmentation rapidly with little or no latency. The response cannot be clearly separated from immediate pigment darkening and is too rapid in onset to be explained by neomelanogenesis. In order to investigate possible mechanisms for this phenomenon, UV-irradiated skin was examined microscopically and ultrastructurally 18 h postirradiation. Specimens from skin sites tanned by exposure to melanogenic doses of UV-A showed a paradoxical reduction in the degree of basal melanization by light microscopy compared to unirradiated skin. Ultrastructurally, there was migration and dispersion of packaged melanosomes within keratinocytes from their normal, aggregated location around the nucleus towards the periphery of the cell. These changes were not observed in specimens exposed to melanogenic doses of UV-B. We propose that UV-A wavelengths can selectively cause redistribution of melanin-laden organelles within human keratinocytes in vivo and that this phenomenon accounts for the visually observed hyperpigmentation that develops soon after single exposures to these wavelengths. Dispersion of melanosomal complexes may be another mechanism by which UV-radiation (UVR) can induce tanning in human skin.

  17. VALIDITATION OF A LIGHT QUESTIONNAIRE WITH REAL-LIFE PHOTOPIC ILLUMINANCE MEASUREMENTS: THE HARVARD LIGHT EXPOSURE ASSESSMENT QUESTIONNAIRE

    Science.gov (United States)

    Bajaj, Archna; Rosner, Bernard; Lockley, Steven; Schernhammer, Eva S.

    2011-01-01

    Background Light exposure at night is now considered a probable carcinogen. To study the effects of light on chronic diseases like cancer, methods to measure light exposure in large observational studies are needed. We aimed to investigate the validity of self-reported current light exposure. Methods We developed a self-administered semiquantitative light questionnaire, the Harvard Light Exposure Assessment (H-LEA) questionnaire, and compared photopic scores derived from this questionnaire with actual photopic and circadian measures obtained from a real-life 7-day light meter application among 132 women (85 rotating night shift workers and 47 day workers) participating in the Nurses' Health Study II. Results After adjustment for age, BMI, collection day, and night work status, the overall partial Spearman correlation between self-report of light exposure and actual photopic light measurements was 0.72 (P<0.001; Kendall τ =0.57) and 0.73 (P<0.0001; Kendall τ =0.58) when correlating circadian light measurements. There were only minimal differences in accuracy of self-report of light exposure and photopic or circadian light measurement between day (r=0.77 and 0.78, respectively) and rotating night shift workers (r=0.68 and 0.69, respectively). Conclusions The results of this study provide evidence of the criterion validity of self-reported light exposure using the H-LEA questionnaire. Impact: This questionnaire is a practical method of assessing light exposure in large scale epidemiologic studies. PMID:21737411

  18. Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night.

    Science.gov (United States)

    Kozaki, Tomoaki; Kubokawa, Ayaka; Taketomi, Ryunosuke; Hatae, Keisuke

    2015-07-04

    Bright nocturnal light has been known to suppress melatonin secretion. However, bright light exposure during the day-time might reduce light-induced melatonin suppression (LIMS) at night. The effective proportion of day-time light to night-time light is unclear; however, only a few studies on accurately controlling both day- and night-time conditions have been conducted. This study aims to evaluate the effect of different day-time light intensities on LIMS. Twelve male subjects between the ages of 19 and 23 years (mean ± S.D., 20.8 ± 1.1) gave informed consent to participate in this study. They were exposed to various light conditions (day-time light conditions). They were then exposed to bright light (300 lx) again between 01:00 and 02:30 (night-time light exposure). They provided saliva samples before (00:55) and after night-time light exposure (02:30). A one-tailed paired t test yielded significant decrements of melatonin concentration after night-time light exposure under day-time dim, 100- and 300-lx light conditions. No significant differences exist in melatonin concentration between pre- and post-night-time light exposure under day-time 900- and 2700-lx light conditions. Present findings suggest the amount of light exposure needed to prevent LIMS caused by ordinary nocturnal light in individuals who have a general life rhythm (sleep/wake schedule). These findings may be useful in implementing artificial light environments for humans in, for example, hospitals and underground shopping malls.

  19. The effect of UV exposure and heat treatment on crystallization behavior of photosensitive glasses

    Science.gov (United States)

    Kıbrıslı, Orhan; Ersundu, Ali Erçin

    2018-05-01

    In this study, photosensitive glasses in the Na2O-ZnO-Al2O3-SiO2 system with photosensitizing agents (cerium, silver, tin, antimony) and halogenides (NaF and KBr) were synthesized through a conventional melt-quenching technique. The crystallization mechanism was investigated for solely heat-treated and UV-exposed + heat-treated samples using differential thermal analysis (DTA), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques to understand the effect of UV exposure on crystallization behavior of photosensitive glasses. Accordingly, non-isothermal DTA measurements were performed at different heating rates to determine crystallization peak, T p, and onset, T c, temperatures. For solely heat-treated samples, the kinetic parameters such as the Avrami constant, n, and morphology index, m, were calculated as 1 from the Ozawa method indicating surface crystallization and the value of crystallization activation energy was calculated as 944 kJ/mol using modified Kissinger method. On the contrary, bulk crystallization was found to be predominant for UV exposed + heat-treated samples revealing that UV exposure is the primary cause of bulk crystallization in photosensitive glasses.

  20. 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.

  1. Ultrastructural analysis of corneal exposure to UV radiation

    International Nuclear Information System (INIS)

    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 -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)

  2. Photocatalytic properties of Au-deposited mesoporous SiO_2–TiO_2 photocatalyst under simultaneous irradiation of UV and visible light

    International Nuclear Information System (INIS)

    Okuno, T.; Kawamura, G.; Muto, H.; Matsuda, A.

    2016-01-01

    Mesoporous SiO_2 templates deposited TiO_2 nanocrystals are synthesized via a sol–gel route, and Au nanoparticles (NPs) are deposited in the tubular mesopores of the templates by a photodeposition method (Au/SiO_2–TiO_2). The photocatalytic characteristics of Au/SiO_2–TiO_2 are discussed with the action spectra of photoreactions of 2-propanol and methylene blue. Photocatalytic activities of SiO_2–TiO_2 under individual ultraviolet (UV) and visible (Vis) light illumination are enhanced by deposition of Au NPs. Furthermore, Au/SiO_2–TiO_2 shows higher photocatalytic activities under simultaneous irradiation of UV and Vis light compared to the activity under individual UV and Vis light irradiation. Since the photocatalytic activity under simultaneous irradiation is almost the same as the total activities under individual UV and Vis light irradiation, it is concluded that the electrons and the holes generated by lights of different wavelengths are efficiently used for photocatalysis without carrier recombination. - Graphical abstract: This graphic shows the possible charge behavior in Au/SiO_2–TiO_2 under independent light irradiation of ultraviolet and visible light irradiation. Both reactions under independent UV and Vis light irradiation occurred in parallel when Au/SiO_2–TiO_2 photocatalyst was illuminated UV and Vis light simultaneously, and then photocatalytic activity is improved by simultaneous irradiation. - Highlights: • Au nanoparticles were deposited in mesoporous SiO_2–TiO_2 by a photodeposition method. • Photocatalytic activity under UV and Vis light was enhanced by deposition of Au. • Photocatalytic activity of Au/SiO_2–TiO_2 was improved by simultaneous irradiation.

  3. Prevention of the adverse photic effects of peripheral light-focusing using UV-blocking contact lenses.

    Science.gov (United States)

    Kwok, L Stephen; Kuznetsov, Valerian A; Ho, Arthur; Coroneo, Minas T

    2003-04-01

    Peripheral light-focusing (PLF) is an occult form of ultraviolet radiation (UVR) hazardous to the human eye. In PLF, obliquely incident light is refracted from the peripheral cornea to concentrated sites inside the anterior segment. In the current study, the directionality of this phenomenon for UVR and whether PLF is established in outdoor settings exposed to sunlight were investigated. The protection provided by a UV-blocking contact lens was also evaluated. UVA and UVB sensors were placed on the nasal limbus of an anatomically based model eye. The temporal limbus was exposed to a UV light source placed at various angles behind the frontal plane. PLF was quantified with the sensor output. The ensemble was mounted in the orbit of a mannequin head and exposed to sunlight in three insolation environments within the region of Sydney, Australia. PLF for UVA and UVB was determined with no eyewear or with sunglasses and commercially available soft contact lenses, with and without UV-blocking capability. The intensity of UVA peaked at approximately 120 degrees incidence, the level at which the UVB response was also at its maximum. The intensification of UVA was up to x18.3. The intensity of PLF for UVA and UVB was reduced by an order of magnitude by a UV-blocking contact lens, whereas a clear contact lenses had a much lesser effect. Only the UV-blocking contact lens achieved a significant effect on UVA and UVB irradiance in the urban, beach, and mountain locales (P UV-blocking soft contact lenses. Sunglasses may be unable to shield oblique rays, unless side protection is incorporated. Contact lenses can offer UVR protection against all angles of incidence, including the peak-response angle. They can also protect the eye in settings in which the wearing of sunglasses is not feasible or convenient.

  4. Photoreactivation of UV-induced pyrimidine dimers and erythema in the marsupial Monodelphis domestica

    International Nuclear Information System (INIS)

    Ley, R.D.

    1985-01-01

    Post-UV treatment of the gray, short-tailed opossum Monodelphis domestica with photoreactivating light (320-400 nm) suppressed the appearance of UV-induced erythema as evidenced by an increase in the dose of UV required to elicit an erythemal response. Pre-UV exposure to photoreactivating light had no effect on the UV induction of erythema. The dose-response for the photoreversal of pyrimidine dimers in epidermal DNA of M. domestica was similar to that for the photoreactivation of erythema induction. These data not only support the notion that DNA is the primary chromophore involved in the induction of erythema but also identify pyrimidine dimers as the major DNA change responsible for its induction. These results also identify M. domestica as a useful whole-animal system with which to determine the role of pyrimidine dimers in other photobiological responses of mammalian skin

  5. The genetic origins of biosynthesis and light-responsive control of the chemical UV screen of land plants

    International Nuclear Information System (INIS)

    Jorgensen, R.

    1994-01-01

    Most land plants possess the capacity to protect themselves from UV light, and do so by producing pigments that absorb efficiently in the UV-A and UV-B regions of the spectrum while allowing transmission of nearly all photosynthetically useful wavelengths. These UV-absorbing pigments are mainly phenylpropanoids and flavonoids. This chapter summarizes current understanding of the mechanism of UV protection in higher land plants, evaluates the information available from lower land plants and their green-algal relatives, and then considers the possible evolutionary origins of this use of chemical filters for selectively screening UV light from solar radiation. It is proposed that photo control over the biosynthesis of UV-absorbing phenylpropanoids and flavonoids may have evolved in concert with the evolution of the high biosynthetic activity necessary for UV protection. The toxicity of phenylpropanoids and flavonoids has been postulated to have been a barrier to the evolution of an effective chemical UV screen, and that some means for sequestering these compounds and/or for controlling their synthesis probably evolved prior to, or in concert with, the evolution of high rates of biosynthesis. The original photoreceptor and signal transduction system is speculated to have been based on photo isomerization of a phenylpropanoid ester and a pre-existing product feedback mechanism for controlling phenylpropanoid biosynthesis. Understanding the original mechanism for photo control of the chemical UV screen of land plants could be valuable for understanding the adaptability of extant land plants to rising levels of solar UV-B radiation and may suggest genetic strategies for engineering improved UV tolerance in crop plants. (author)

  6. Protocol for Determining Ultraviolet Light Emitting Diode (UV-LED) Fluence for Microbial Inactivation Studies.

    Science.gov (United States)

    Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

    2018-06-15

    Determining fluence is essential to derive the inactivation kinetics of microorganisms and to design ultraviolet (UV) reactors for water disinfection. UV light emitting diodes (UV-LEDs) are emerging UV sources with various advantages compared to conventional UV lamps. Unlike conventional mercury lamps, no standard method is available to determine the average fluence of the UV-LEDs, and conventional methods used to determine the fluence for UV mercury lamps are not applicable to UV-LEDs due to the relatively low power output, polychromatic wavelength, and specific radiation profile of UV-LEDs. In this study, a method was developed to determine the average fluence inside a water suspension in a UV-LED experimental setup. In this method, the average fluence was estimated by measuring the irradiance at a few points for a collimated and uniform radiation on a Petri dish surface. New correction parameters were defined and proposed, and several of the existing parameters for determining the fluence of the UV mercury lamp apparatus were revised to measure and quantify the collimation and uniformity of the radiation. To study the effect of polychromatic output and radiation profile of the UV-LEDs, two UV-LEDs with peak wavelengths of 262 and 275 nm and different radiation profiles were selected as the representatives of typical UV-LEDs applied to microbial inactivation. The proper setup configuration for microorganism inactivation studies was also determined based on the defined correction factors.

  7. Photoinhibition and photosynthetic pigment reorganisation dynamics in light/darkness cycles as photoprotective mechanisms of Porphyra umbilicalis against damaging effects of UV radiation

    Directory of Open Access Journals (Sweden)

    José Aguilera

    2008-03-01

    Full Text Available Porphyra umbilicalis L. Kutzing collected from the upper intertidal zone at Helgoland, North Sea, was exposed to different spectral ranges of UV radiation under both 12/12 h light/dark cycles and continuous irradiation. In light/dark cycles, oscillations of the optimal quantum yield (Fv /Fm were observed during the experiments, reaching maximal values at the end of the light phase followed by lower values during the dark phase. Decreased Fv /Fm was observed in thalli illuminated with photosynthetic active radiation (PAR plus UV-A and PAR+UV-A+UV-B, compared with the PAR control, indicating a certain degree of UV-induced photoinhibition. In addition, a decrease in the percentage of change of the linear initial slope and maximum electron transport rate (ETR estimated from ETR vs. irradiance curves was induced by UV radiation during the light phase. Recovery during the 12 h dark phase was almost completed in UV-A treated plants. PAR+UV-A seemed not to affect the photosynthesis, measured as O2 production. However, a decrease in O2 production was observed in the PAR+UV-A+UV-B treatment, but it recovered to initial values after 48 h of culture. No changes in total content of photosynthetic pigments were observed. However, thallus absorptance and the in vivo absorption cross-section in the PAR range (400-700 nm normalised to Chl a (a* parameter fluctuated during light/dark cycles and were positively correlated with changes in the optimum quantum yield, thus indicating that daily pigment reorganisation in the light-harvesting complex may play a key role in the photosynthetic performance of the algae. Both UV-A and UV-B treatments under continuous irradiation induced a significant reduction in the optimal quantum yield, ETR efficiency and photosynthetic oxygen production during the first 36 h to values around 30% of the initial ones. Thus, different protective mechanisms against UV stress can be observed in P. umbilicalis: dynamic photoinhibition when

  8. Enhancement of SV40 transformation by treatment of C3H2K cells with uv light and caffeine. I. Combined effect of uv light and caffeine

    International Nuclear Information System (INIS)

    Ide, T.; Anzai, K.; Andoh, T.

    1975-01-01

    Treatment of cultured mouse cells, C3H2K, with uv light and/or caffeine enhanced the frequency of SV40-induced transformation. This enhancement depends upon the doses of uv and caffeine and the mode of combination of these agents. Irradiation of cells with increasing doses of uv just before infection resulted in approximately 2-fold enhancement of the transformation frequency up to a dose of 90 ergs/mm 2 and 3.3-fold at 150 ergs/mm 2 . Addition of 1 mM caffeine to the medium for 4 days subsequent to infection brought about a 2-fold enhancement. When cells were irradiated and treated with 1 mM caffeine, the enhancement was approximately 4-fold up to a uv dose of 90 ergs/mm 2 and 5.9-fold at 150 ergs/mm 2 . When 0.1 to 4 mM caffeine was added for 4 days postinfection, the absolute number of transformations increased, and an enhancement ratio of 1.3 to 6.8 resulted. After the addition of the same increasing doses of caffeine to uv-irradiated cells (75 ergs/mm 2 ), the enhancement of transformation frequency was even higher ranging 2.0 to 13.3. The transformation frequencies thus obtained by the double treatment were always higher than those predicted if uv and caffeine acted additively. The transformation frequency was little affected by the addition of dibutyrylcyclic AMP and theophylline

  9. Effect of light on Thiobacilli

    International Nuclear Information System (INIS)

    Le Roux, N.W.; Marshall, V.M.

    1977-01-01

    The aim was to study the effect of visible and ultra-violet light on some members of the genus Thiobacillus. This genus is one more example of an aerobic organism which undergoes what appears to be the widespread phenomenon of light inhibition. Light inhibition of thiobacilli has been observed before and these other observations are presented. In the present study the effect of both visible and U-V light on three species was considered, viz. T. thiooxidans, T. thioparus and T. ferrooxidans, the latter species being studied more thoroughly with respect to different intensities and wavelengths of light and the shielding effect of bacterial numbers and ferric iron. The photoreactivation of T. ferrooxidans cells after irradiation by U-V light was also examined. Using unfiltered, visible light, there was an inhibitory effect on all three of the thiobacilli irrespective of the source being used. When selected wavelengths were studied it was seen that the blue end of the visible spectrum was most inhibitory. A relationship between ferric iron concentration and protection from visible light was shown and the beneficial protective effect of particulate suspensions was demonstrated. The sensitivity of T. ferrooxidans and T. thioparus to U-V light and the protection afforded by ferric iron and cell numbers was assessed. Photoreactivation of U-V irradiated cells by exposure to visible light showed that this phenomenon occurred using wavelengths of visible light which, by themselves, were inhibitory. Some practical implication of these findings are offered. (orig.) [de

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  11. Current schemes for National Synchrotron Light Source UV beamlines

    International Nuclear Information System (INIS)

    Williams, G.P.; Howells, M.R.; McKinney, W.R.

    1979-01-01

    We describe in some detail four beamlines proposed for the National Synchrotron Light Source uv ring at Brookhaven National Laboratory. Three grazing-incidence instruments, one of the plane grating Mijake type and two with toroidal gratings at grazing angles of 2-1/2 0 and 15 0 are described. Two normal incidence instruments, one using the source as entrance slit and accepting 75 milliradians horizontally are also discussed. In each case we have estimated the output fluxes expected from such beamlines

  12. Ferric ion mediated photochemical decomposition of perfluorooctanoic acid (PFOA) by 254 nm UV light

    International Nuclear Information System (INIS)

    Wang Yuan; Zhang Pengyi; Pan Gang; Chen Hao

    2008-01-01

    The great enhancement of ferric ion on the photochemical decomposition of environmentally persistent perfluorooctanoic acid (PFOA) under 254 nm UV light was reported. In the presence of 10 μM ferric ion, 47.3% of initial PFOA (48 μM) was decomposed and the defluorination ratio reached 15.4% within 4 h reaction time. While the degradation and defluorination ratio greatly increased to 80.2% and 47.8%, respectively, when ferric ion concentration increased to 80 μM, and the corresponding half-life was shortened to 103 min. Though the decomposition rate was significantly lowered under nitrogen atmosphere, PFOA was efficiently decomposed too. Other metal ions like Cu 2+ and Zn 2+ also slightly improved the photochemical decomposition of PFOA under irradiation of 254 nm UV light. Besides fluoride ion, other intermediates during PFOA decomposition including formic acid and five shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4 and C3, respectively, were identified and quantified by IC or LC/MS. The mixture of PFOA and ferric ion had strong absorption around 280 nm. It is proposed that PFOA coordinates with ferric ion to form a complex, and its excitation by 254 nm UV light leads to the decomposition of PFOA in a stepwise way

  13. Shining Light on Skin Pigmentation: The Darker and the Brighter Side of Effects of UV Radiation†

    Science.gov (United States)

    Maddodi, Nityanand; Jayanthy, Ashika; Setaluri, Vijayasaradhi

    2012-01-01

    The term barrier function as applied to human skin often connotes the physical properties of this organ that provide protection from its surrounding environment. This term does not generally include skin pigmentation. However, skin pigmentation, which is the result of melanin produced in melanocytes residing the basal layer of the skin and exported to the keratinocytes in the upper layers, serves equally important protective function. Indeed, changes in skin pigmentation are often the most readily recognized indicators of exposure of skin to damaging agents, especially to natural and artificial radiation in the environment. Several recent studies have shed new light on a) the mechanisms of involved in selective effects of subcomponents of UV radiation on human skin pigmentation and b) the interactive influences between keratinocytes and melanocytes, acting as ‘epidermal melanin unit’, that manifest as changes in skin pigmentation in response to exposure to various forms of radiation. This article provides a concise review of our current understanding of the effects of the non-ionizing solar radiation, at cellular and molecular levels, on human skin pigmentation. PMID:22404235

  14. UV Treatment of the Stabilizing Shell for Improving the Photostability of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Silvia Rinaldi

    2016-01-01

    Full Text Available Silver nanoparticles or nanoclusters are quite sensitive to light exposure. In particular, irradiation in the localized surface plasmon resonance (LSPR region brings about a drastic modification of their optical properties due to growth and reshaping of the nanoparticles. In order to obtain luminescent colloids, small silver colloidal nanoparticles were prepared in chloroform using vinylpyrrolidone oligomers as capping agent and their luminescence properties were used to control their stability upon prolonged exposure to visible light. The polymeric shell around the metal clusters was hardened through photo-cross-linking by UV light. This process did not alter the morphology and the optical properties of the nanoparticles but greatly improved the particle photostability as confirmed also by confocal laser scanning microscopy measurements. The data clearly show that UV curing of the stabilizing layer could be a simple postsynthetic procedure to obtain materials with stable properties.

  15. Effects of Radon and UV Exposure on Skin Cancer Mortality in Switzerland

    NARCIS (Netherlands)

    Vienneau, Danielle; de Hoogh, Kees; Hauri, Dimitri D.; Vicedo-Cabrera, Ana M; Schindler, Christian; Huss, Anke; Röösli, Martin

    2017-01-01

    BACKGROUND: Skin cancer incidence in Switzerland is among the highest in the world. In addition to exposure to ultraviolet (UV) radiation, radon alpha particles attached to aerosols can adhere to the skin and potentially cause carcinogenic effects. OBJECTIVES: We investigated the effects of radon

  16. Tunable UV- and Visible-Light Photoresponse Based on p-ZnO Nanostructures/n-ZnO/Glass Peppered with Au Nanoparticles.

    Science.gov (United States)

    Hsu, Cheng-Liang; Lin, Yu-Hong; Wang, Liang-Kai; Hsueh, Ting-Jen; Chang, Sheng-Po; Chang, Shoou-Jinn

    2017-05-03

    UV- and visible-light photoresponse was achieved via p-type K-doped ZnO nanowires and nanosheets that were hydrothermally synthesized on an n-ZnO/glass substrate and peppered with Au nanoparticles. The K content of the p-ZnO nanostructures was 0.36 atom %. The UV- and visible-light photoresponse of the p-ZnO nanostructures/n-ZnO sample was roughly 2 times higher than that of the ZnO nanowires. The Au nanoparticles of various densities and diameter sizes were deposited on the p-ZnO nanostructures/n-ZnO samples by a simple UV photochemical reaction method yielding a tunable and enhanced UV- and visible-light photoresponse. The maximum UV and visible photoresponse of the Au nanoparticle sample was obtained when the diameter size of the Au nanoparticle was approximately 5-35 nm. On the basis of the localized surface plasmon resonance effect, the UV, blue, and green photocurrent/dark current ratios of Au nanoparticle/p-ZnO nanostructures/n-ZnO are ∼1165, ∼94.6, and ∼9.7, respectively.

  17. 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)

    Bishop, S.C.

    1979-01-01

    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)

  18. Using the Transient Response of WO3 Nanoneedles under Pulsed UV Light in the Detection of NH3 and NO2

    Directory of Open Access Journals (Sweden)

    Oriol Gonzalez

    2018-04-01

    Full Text Available Here we report on the use of pulsed UV light for activating the gas sensing response of metal oxides. Under pulsed UV light, the resistance of metal oxides presents a ripple due to light-induced transient adsorption and desorption phenomena. This methodology has been applied to tungsten oxide nanoneedle gas sensors operated either at room temperature or under mild heating (50 °C or 100 °C. It has been found that by analyzing the rate of resistance change caused by pulsed UV light, a fast determination of gas concentration is achieved (ten-fold improvement in response time. The technique is useful for detecting both oxidizing (NO2 and reducing (NH3 gases, even in the presence of different levels of ambient humidity. Room temperature operated sensors under pulsed UV light show good response towards ammonia and nitrogen dioxide at low power consumption levels. Increasing their operating temperature to 50 °C or 100 °C has the effect of further increasing sensitivity.

  19. Photochemical Synthesis of Complex Carbazoles: Evaluation of Electronic Effects in Both UV- and Visible-Light Methods in Continuous Flow.

    Science.gov (United States)

    Hernandez-Perez, Augusto C; Caron, Antoine; Collins, Shawn K

    2015-11-09

    An evaluation of both a visible-light- and UV-light-mediated synthesis of carbazoles from various triarylamines with differing electronic properties under continuous-flow conditions has been conducted. In general, triarylamines bearing electron-rich groups tend to produce higher yields than triarylamines possessing electron-withdrawing groups. The incorporation of nitrogen-based heterocycles, as well as halogen-containing arenes in carbazole skeletons, was well tolerated, and often synthetically useful complementarity was observed between the UV-light and visible-light (photoredox) methods. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Increase of vitamin D2 by UV-B exposure during the growth phase of white button mushroom (Agaricus bisporus)

    DEFF Research Database (Denmark)

    Kristensen, Hanne; Rosenqvist, Eva S. K.; Jakobsen, Jette

    2012-01-01

    Background: Mushrooms are the only non-animal food source of vitamin D. Wild mushrooms have naturally high vitamin D2 content, and cultivated mushrooms produce vitamin D2 from ergosterol when exposed to supplementary UV-B during the post-harvest phase. Objectives: This study investigated...... with exposure to supplementary UV-B just prior to harvest in the range of 0-2,400 mJ cm-2. Mushrooms grew for 2 days with or without repeated UV-B exposure each day. Vitamin D2 and growth rate were determined. Some mushrooms were post-harvest treated by exposure at 200 mJ cm-2 supplementary UV-B or natural...... sunlight, prior to vitamin D2 determination. Results: The content of vitamin D2 was 0.2-164 µg 100 g-1 fresh weight (FW), and there was a linear relationship between UV-dose up to 1,000 mJ cm-2 and vitamin D2 content. The fast growth rate of the mushrooms diluted the vitamin D2 from 24 to 3 µg 100 g-1...

  1. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds?

    International Nuclear Information System (INIS)

    Thune, P.

    1991-01-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab

  2. Light interaction with nano-structured diatom frustule, from UV-A to NIR

    DEFF Research Database (Denmark)

    Maibohm, Christian; Nielsen, Josefine Holm; Rottwitt, Karsten

    2016-01-01

    symmetry where morphological parameters vary between the different investigated species. We report how light interacts with the frustule in the wavelength range from UV-A (320-380 nm) to NIR (900 nm). High resolution spectroscopy and CCD images are used to identify photoluminescence (PL) and variations...

  3. Visible Light Induces Melanogenesis in Human Skin through a Photoadaptive Response

    Science.gov (United States)

    Randhawa, Manpreet; Seo, InSeok; Liebel, Frank; Southall, Michael D.; Kollias, Nikiforos; Ruvolo, Eduardo

    2015-01-01

    Visible light (400–700 nm) lies outside of the spectral range of what photobiologists define as deleterious radiation and as a result few studies have studied the effects of visible light range of wavelengths on skin. This oversight is important considering that during outdoors activities skin is exposed to the full solar spectrum, including visible light, and to multiple exposures at different times and doses. Although the contribution of the UV component of sunlight to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology in terms of inflammation, and limited information is available regarding the role of visible light on pigmentation. The purpose of this study was to determine the effect of visible light on the pro-pigmentation pathways and melanin formation in skin. Exposure to visible light in ex-vivo and clinical studies demonstrated an induction of pigmentation in skin by visible light. Results showed that a single exposure to visible light induced very little pigmentation whereas multiple exposures with visible light resulted in darker and sustained pigmentation. These findings have potential implications on the management of photo-aggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions. PMID:26121474

  4. Visible Light Induces Melanogenesis in Human Skin through a Photoadaptive Response.

    Science.gov (United States)

    Randhawa, Manpreet; Seo, InSeok; Liebel, Frank; Southall, Michael D; Kollias, Nikiforos; Ruvolo, Eduardo

    2015-01-01

    Visible light (400-700 nm) lies outside of the spectral range of what photobiologists define as deleterious radiation and as a result few studies have studied the effects of visible light range of wavelengths on skin. This oversight is important considering that during outdoors activities skin is exposed to the full solar spectrum, including visible light, and to multiple exposures at different times and doses. Although the contribution of the UV component of sunlight to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology in terms of inflammation, and limited information is available regarding the role of visible light on pigmentation. The purpose of this study was to determine the effect of visible light on the pro-pigmentation pathways and melanin formation in skin. Exposure to visible light in ex-vivo and clinical studies demonstrated an induction of pigmentation in skin by visible light. Results showed that a single exposure to visible light induced very little pigmentation whereas multiple exposures with visible light resulted in darker and sustained pigmentation. These findings have potential implications on the management of photo-aggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions.

  5. Visible Light Induces Melanogenesis in Human Skin through a Photoadaptive Response.

    Directory of Open Access Journals (Sweden)

    Manpreet Randhawa

    Full Text Available Visible light (400-700 nm lies outside of the spectral range of what photobiologists define as deleterious radiation and as a result few studies have studied the effects of visible light range of wavelengths on skin. This oversight is important considering that during outdoors activities skin is exposed to the full solar spectrum, including visible light, and to multiple exposures at different times and doses. Although the contribution of the UV component of sunlight to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology in terms of inflammation, and limited information is available regarding the role of visible light on pigmentation. The purpose of this study was to determine the effect of visible light on the pro-pigmentation pathways and melanin formation in skin. Exposure to visible light in ex-vivo and clinical studies demonstrated an induction of pigmentation in skin by visible light. Results showed that a single exposure to visible light induced very little pigmentation whereas multiple exposures with visible light resulted in darker and sustained pigmentation. These findings have potential implications on the management of photo-aggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions.

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  7. Decolourisation of simulated reactive dyebath effluents by electrochemical oxidation assisted by UV light.

    Science.gov (United States)

    López-Grimau, V; Gutiérrez, M C

    2006-01-01

    This study is focused on the optimisation of the electrochemical decolourisation of textile effluents containing reactive dyes with the aim of making feasible-technically and economically-this method at industrial scale. Coloured waters were treated in continuous at low current density, to reduce the electrical consumption. Ti/PtO(x) electrodes were used to oxidize simulated dyebaths prepared with an azo/dichlorotriazine reactive dye (C.I. Reactive Orange 4). The decolourisation yield was dependent on the dyeing electrolyte (NaCl or Na(2)SO(4)). Dyeing effluents which contained from 0.5 to 20 gl(-1) of NaCl reached a high decolourisation yield, depending on the current density, immediately after the electrochemical process. These results were improved when the effluents were stored for several hours under solar light. After the electrochemical treatment the effluents were stored in a tank and exposed under different lighting conditions: UV light, solar light and darkness. The evolution of the decolourisation versus the time of storage was reported and kinetic constants were calculated. The time of storage was significantly reduced by the application of UV light. A dye mineralization study was also carried out on a concentrated dyebath. A TOC removal of 81% was obtained when high current density was applied for a prolonged treatment with recirculation. This treatment required a high electrical consumption.

  8. The effects of multiple UV exposures on HIV-LTR (long terminal repeat) expression

    International Nuclear Information System (INIS)

    Schreck, S.; Milton, J.; Panozzo, J.; Libertin, C.R.; Woloschak, G.E.; Loyola Univ., Maywood, IL

    1995-01-01

    Previous studies have shown that cellular stress agents such as UV radiation induce transcription from the long terminal repeat (LTR) of the human immunodeficiency virus (HIV). Using HeLa cells stably transfected with the HIV-LTR sequence, which transcriptionally drives the chloramphenicol acetyl transferase (CAT) reporter gene, we examined the effects of multiple exposures to UVC (254 nm) on HIV-LTR-CAT expression. Low doses (≤ 5 J m -2 ) had no effect on CAT expression, but up to 29-fold induction was observed with 10 J m -2 when cells were harvested 48 h after completion of the exposure. Little difference was noted in induction levels when cells were exposed to one 25 J m -2 dose, viable cells were harvested at 24 h, 48 h or 72 h, and cell lysates were assayed for CAT expression. Two sequential 12.5 J m -2 exposures, given 24 h apart, resulted in an additive effect on CAT expression; these two exposures produced CAT activity equivalent to that induced following a single 25 J m -2 dose. Our data suggest that HIV-LTR requires a specific threshold UV dose in order to elicit induction; a maximal induction dose is also evident; exposures higher than this maximal dose contribute no more to HIV-LTR induction in viable cells. (author)

  9. UV light induced photodegradation of organic dye by ZnO nanocatalysts

    International Nuclear Information System (INIS)

    Sumesh, C. K.; Patel, Bhavin; Parekh, Kinnari

    2013-01-01

    Ultraviolet light induced photocatalytic activity of ZnO nanocatalyst prepared using a wet chemical precipitation route and mineralization of the methyl orange (MO) dye has been carried out in a photocatalytic reactor. The degradation of the MO was monitored spectrophotometrically and showed a decolorization efficiency of 92% after nine hours of irradiation in the MO-ZnO/UV light system. The blue shifting of maximum peak position of the MO and the formation of extra peak at 247 nm during irradiation time advances revealed that MO degrades in the form of intermediates during the photocatalytic process.

  10. Occupational exposure to ultraviolet radiation and risk of non-melanoma skin cancer in a multinational European study.

    Directory of Open Access Journals (Sweden)

    Simona Surdu

    Full Text Available BACKGROUND: Studies suggest that ambient sunlight plays an important role in the pathogenesis of non-melanoma skin cancers (NMSC. However, there is ongoing controversy regarding the relevance of occupational exposure to natural and artificial ultraviolet radiation (UV radiation. OBJECTIVES: We investigated potential associations between natural and artificial UV radiation exposure at work with NMSC in a case-control study conducted in Hungary, Romania, and Slovakia. METHODS: Occupational exposures were classified by expert assessment for 527 controls and 618 NMSC cases (515 basal cell carcinoma, BCC. Covariate information was collected via interview and multiple logistic regression models were used to assess associations between UV exposure and NMSC. RESULTS: Lifetime prevalence of occupational exposure in the participants was 13% for natural UV radiation and 7% for artificial UV radiation. Significant negative associations between occupational exposure to natural UV radiation and NMSC were detected for all who had ever been exposed (odds ratio (OR 0.47, 95% confidence interval (CI 0.27-0.80; similar results were detected using a semi-quantitative metric of cumulative exposure. The effects were modified by skin complexion, with significantly decreased risks of BCC among participants with light skin complexion. No associations were observed in relation to occupational artificial UV radiation exposure. CONCLUSIONS: The protective effect of occupational exposure to natural UV radiation was unexpected, but limited to light-skinned people, suggesting adequate sun-protection behaviors. Further investigations focusing on variations in the individual genetic susceptibility and potential interactions with environmental and other relevant factors are planned.

  11. 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)

    Cen, Y.-P.; Bornman, J.F.

    1993-01-01

    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-B BE ) 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)

  12. UV B-induced vertical migrations of cyanobacteria in a microbial mat

    International Nuclear Information System (INIS)

    Rebout, B.M.; Garcia-Pichel, F.

    1995-01-01

    Exposure to moderate doses of UV B (0.35 to 0.79 W m -2 s -1 or 0.98 to 2.2 μmol of photons m -2 s -1 at 310 nm) caused the surface layers of microbial mats from Solar Lake, Sinai, Egypt, to become visibly lighter green. Concurrent with the color change were rapid and dramatic reductions in gross photosynthesis and in the resultant high porewater oxygen concentrations in the surface layers of the mats. The depths at which both maximum gross photosynthesis and maximum oxygen concentrations occurred were displaced downward. In contrast, gross photosynthesis in the deeper layers of the mats increased in response to UV B incident upon the surface. The cessation of exposure to UV B partially reversed all of these changes. Taken together, these responses suggest that photoautotrophic members of the mat community, most likely the dominant cyanobacterium Microcoleus chthonoplastes, were migrating in response to the added UV B. The migration phenomenon was also observed in response to increases in visible radiation and UV A, but UV B was ca. 100-fold more effective than visible radiation and ca. 20-fold more effective than UV A in provoking the response. Migrating microorganisms within this mat are apparently able to sense UV B directly and respond behaviorally to limit their exposure to UV. Because of strong vertical gradients of light and dissolved substances in microbial mats, the migration and the resultant vertical redistribution of photosynthetic activity have important consequences for both the photobiology of the cyanobacteria and the net primary productivity of the mat ecosystem

  13. Thermoluminescence properties of Eu and Li co-doped Gd2O3, induced by UV light

    International Nuclear Information System (INIS)

    Hristov, H; Arhangelova, N; Velev, V; Uzunov, N M; Baneva, Y; Nedeva, D; Penev, I; Moschini, G; Rossi, P

    2012-01-01

    For some specific biomedical applications, connected with in-situ measurements of the absorbed dose of ultraviolet (UV) light, we have developed materials, sensitive to the light emission with a wavelength up to 320nm. Thermoluminescence (TL) yield of Gd 2 O 3 , doped with Eu and Li has been analysed with respect to the quantity of Li co-dopant. Lithium has been added as Li 2 CO 3 to a mixture of Gd 2 O 3 with 10 wt% Eu 2 O 3 . Pellets with the mixture have been sintered at a temperature of 1000°C. The kinetic parameters of the phosphors thus obtained have been studied from the TL glow curves after irradiation with UV light. It has been demonstrated that the addition of 16 wt% of Li 2 CO 3 to the Eu-doped Gd 2 O 3 yields a maximum intensity of the peaks at 87°C and at 145°C. Studies on the kinetic parameters as well as the TL properties of Eu-doped Gd 2 O 3 with the addition of 16% of Li 2 CO 3 have been conducted. It has been measured that two of the TL peaks of this phosphor have relatively long fading. Analysis of the TL properties of the phosphors obtained from Gd 2 O 3 , doped with Eu and Li, shows that they possess good sensitivity to the UV emission and could be used as appropriate phosphors for detection and quantitative measurements of UV light.

  14. Photocatalytic Degradation of Toluene, Butyl Acetate and Limonene under UV and Visible Light with Titanium Dioxide-Graphene Oxide as Photocatalyst

    Directory of Open Access Journals (Sweden)

    Birte Mull

    2017-01-01

    Full Text Available Photocatalysis is a promising technique to reduce volatile organic compounds indoors. Titanium dioxide (TiO2 is a frequently-used UV active photocatalyst. Because of the lack of UV light indoors, TiO2 has to be modified to get its working range shifted into the visible light spectrum. In this study, the photocatalytic degradation of toluene, butyl acetate and limonene was investigated under UV LED light and blue LED light in emission test chambers with catalysts either made of pure TiO2 or TiO2 modified with graphene oxide (GO. TiO2 coated with different GO amounts (0.75%–14% were investigated to find an optimum ratio for the photocatalytic degradation of VOC in real indoor air concentrations. Most experiments were performed at a relative humidity of 0% in 20 L emission test chambers. Experiments at 40% relative humidity were done in a 1 m³ emission test chamber to determine potential byproducts. Degradation under UV LED light could be achieved for all three compounds with almost all tested catalyst samples up to more than 95%. Limonene had the highest degradation of the three selected volatile organic compounds under blue LED light with all investigated catalyst samples.

  15. Perchlorates on Mars enhance the bacteriocidal effects of UV light.

    Science.gov (United States)

    Wadsworth, Jennifer; Cockell, Charles S

    2017-07-06

    Perchlorates have been identified on the surface of Mars. This has prompted speculation of what their influence would be on habitability. We show that when irradiated with a simulated Martian UV flux, perchlorates become bacteriocidal. At concentrations associated with Martian surface regolith, vegetative cells of Bacillus subtilis in Martian analogue environments lost viability within minutes. Two other components of the Martian surface, iron oxides and hydrogen peroxide, act in synergy with irradiated perchlorates to cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60 seconds of exposure. These data show that the combined effects of at least three components of the Martian surface, activated by surface photochemistry, render the present-day surface more uninhabitable than previously thought, and demonstrate the low probability of survival of biological contaminants released from robotic and human exploration missions.

  16. Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens

    Science.gov (United States)

    Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun

    2015-01-01

    Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm2. At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens. PMID:26162872

  17. Effect of temperature during UV and gamma irradiations of TL phosphor CaSO4:Dy

    International Nuclear Information System (INIS)

    Nagpal, J.S.; Pendurkar, H.K.

    1979-01-01

    Temperature is an important parameter in thermoluminescence studies. Irradiation at enhanced temperatures reduces the γ response of TL phosphor CaSO 4 :Dy. However, in the presence of fluorescent lights, the γ response of the phosphor is enhanced by approximately 20% for temperatures around 60-100 0 C. If the phosphor temperature during UV exposure is kept high, the integrated TL output continues to increase until it reaches 18 times at 160 0 C as compared to that produced by UV exposure at room temperature. (Auth.)

  18. Effect of caffeine on the ultraviolet light induction of SV40 virus from transformed hamster cells

    International Nuclear Information System (INIS)

    Zamansky, G.B.; Kleinman, L.F.; Little, J.B.; Black, P.H.; Kaplan, J.C.

    1976-01-01

    The effect of caffeine on the uv light induction of SV40 virus from two transformed hamster cell lines heterogeneous for the induction of infectious virus was studied. The amount of virus induced was significantly increased in both cell lines when exposure to uv light was followed by treatment with caffeine. Caffeine in the absence of uv irradiation did not stimulate virus induction, nor did it stimulate SV40 replication in a lytic infection. There was an apparent difference in the concentrations of caffeine which maximally stimulated SV40 virus induction in the two cell lines. This effect could not be explained by differences in cell survival after exposure to uv light and caffeine. Since caffeine is known to cause the accumulation of gaps formed in DNA during postreplication repair of uv-irradiated rodent cells, our results support the hypothesis that the formation of gaps or breaks in DNA is an important early step in virus induction

  19. UV-induced effects

    NARCIS (Netherlands)

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

    2005-01-01

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

  20. Alteration of five organic compounds by glow discharge plasma and UV light under simulated Mars conditions

    Science.gov (United States)

    Hintze, Paul E.; Buhler, Charles R.; Schuerger, Andrew C.; Calle, Luz M.; Calle, Carlos I.

    2010-08-01

    The Viking missions to Mars failed to detect any organic material in regolith samples. Since then, several removal mechanisms of organic material have been proposed. Two of these proposed methods are removal due to exposure to plasmas created in dust devils and exposure to UV irradiation. The experiments presented here were performed to identify similarities between the two potential removal mechanisms and to identify any compounds produced from these mechanisms that would have been difficult for the Viking instruments to detect. Five organic compounds, phenanthrene, octadecane, octadecanoic acid, decanophenone and benzoic acid, were exposed to a glow discharge plasma created in simulated martian atmospheres as might be present in dust devils, and to UV irradiation similar to that found at the surface of Mars. Glow discharge exposure was carried out in a chamber with 6.9 mbar pressure of a Mars like gas composed mostly of carbon dioxide. The plasma was characterized using emission spectroscopy and found to contain cations and excited neutral species including carbon dioxide, carbon monoxide, and nitrogen. UV irradiation experiments were performed in a Mars chamber which simulates the temperature, pressure, atmospheric composition, and UV fluence rates of equatorial Mars. The non-volatile residues left after each exposure were characterized by mass loss, infrared spectroscopy and high resolution mass spectrometry. Oxidized, higher molecular weight versions of the parent compounds containing carbonyl, hydroxyl and alkenyl functional groups were identified. The presence of these oxidized compounds suggests that searches for organic material in soils on Mars use instrumentation suitable for detection of compounds which contain the above functional groups. Discussions of possible reaction mechanisms are given.

  1. Investigating the protective properties of milk phospholipids against ultraviolet light exposure in a skin equivalent model

    Science.gov (United States)

    Russell, Ashley; Laubscher, Andrea; Jimenez-Flores, Rafael; Laiho, Lily H.

    2010-02-01

    Current research on bioactive molecules in milk has documented health advantages of bovine milk and its components. Milk Phospholipids, selected for this study, represent molecules with great potential benefit in human health and nutrition. In this study we used confocal reflectance and multiphoton microscopy to monitor changes in skin morphology upon skin exposure to ultraviolet light and evaluate the potential of milk phospholipids in preventing photodamage to skin equivalent models. The results suggest that milk phospholipids act upon skin cells in a protective manner against the effect of ultraviolet (UV) radiation. Similar results were obtained from MTT tissue viability assay and histology.

  2. Enhanced photocatalytic activity for H2 evolution under irradiation of UV-vis light by Au-modified nitrogen-doped TiO2.

    Science.gov (United States)

    Zhao, Weirong; Ai, Zhuyu; Dai, Jiusong; Zhang, Meng

    2014-01-01

    Photocatalytic water splitting for hydrogen evolution is a potential way to solve many energy and environmental issues. Developing visible-light-active photocatalysts to efficiently utilize sunlight and finding proper ways to improve photocatalytic activity for H2 evolution have always been hot topics for research. This study attempts to expand the use of sunlight and to enhance the photocatalytic activity of TiO2 by N doping and Au loading. Au/N-doped TiO2 photocatalysts were synthesized and successfully used for photocatalytic water splitting for H2 evolution under irradiation of UV and UV-vis light, respectively. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and photoelectrochemical characterizations. DRS displayed an extension of light absorption into the visible region by doping of N and depositing with Au, respectively. PL analysis indicated electron-hole recombination due to N doping and an efficient inhibition of electron-hole recombination due to the loaded Au particles. Under the irradiation of UV light, the photocatalytic hydrogen production rate of the as-synthesized samples followed the order Au/TiO2 > Au/N-doped TiO2 > TiO2 > N-doped TiO2. While under irradiation of UV-vis light, the N-TiO2 and Au/N-TiO2 samples show higher H2 evolution than their corresponding nitrogen-free samples (TiO2 and Au/TiO2). This inconsistent result could be attributed to the doping of N and the surface plasmonic resonance (SPR) effect of Au particles extending the visible light absorption. The photoelectrochemical characterizations further indicated the enhancement of the visible light response of Au/N-doped TiO2. Comparative studies have shown that a combination of nitrogen doping and Au loading enhanced the visible light response of TiO2 and increased the utilization of solar energy, greatly

  3. Enhanced photocatalytic activity for H2 evolution under irradiation of UV-vis light by Au-modified nitrogen-doped TiO2.

    Directory of Open Access Journals (Sweden)

    Weirong Zhao

    Full Text Available BACKGROUND PURPOSE: Photocatalytic water splitting for hydrogen evolution is a potential way to solve many energy and environmental issues. Developing visible-light-active photocatalysts to efficiently utilize sunlight and finding proper ways to improve photocatalytic activity for H2 evolution have always been hot topics for research. This study attempts to expand the use of sunlight and to enhance the photocatalytic activity of TiO2 by N doping and Au loading. METHODS: Au/N-doped TiO2 photocatalysts were synthesized and successfully used for photocatalytic water splitting for H2 evolution under irradiation of UV and UV-vis light, respectively. The samples were characterized using X-ray diffraction (XRD, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, UV-vis diffuse reflectance spectroscopy (DRS, photoluminescence spectroscopy (PL, and photoelectrochemical characterizations. RESULTS: DRS displayed an extension of light absorption into the visible region by doping of N and depositing with Au, respectively. PL analysis indicated electron-hole recombination due to N doping and an efficient inhibition of electron-hole recombination due to the loaded Au particles. Under the irradiation of UV light, the photocatalytic hydrogen production rate of the as-synthesized samples followed the order Au/TiO2 > Au/N-doped TiO2 > TiO2 > N-doped TiO2. While under irradiation of UV-vis light, the N-TiO2 and Au/N-TiO2 samples show higher H2 evolution than their corresponding nitrogen-free samples (TiO2 and Au/TiO2. This inconsistent result could be attributed to the doping of N and the surface plasmonic resonance (SPR effect of Au particles extending the visible light absorption. The photoelectrochemical characterizations further indicated the enhancement of the visible light response of Au/N-doped TiO2. CONCLUSION: Comparative studies have shown that a combination of nitrogen doping and Au loading enhanced the visible light response of

  4. Sleep-Wake Actigraphy and Light Exposure During Spaceflight-Long

    Science.gov (United States)

    Czeisler, Charles A.; Barger, Laura K.; Wright, Kenneth P., Jr.; Ronda, Joseph

    2009-01-01

    Sleep-Wake Actigraphy and Light Exposure During Spaceflight-Long (Sleep-Long) will examine the effects of spaceflight and ambient light exposure on the sleep-wake cycles of the crew members during long-duration stays on the space station.

  5. Modification of UV-induced mutation frequencies in Chinese hamster- cells by dose fractionation, cycloheximide and caffeine treatments

    International Nuclear Information System (INIS)

    Chang, C.-C.; Schultz, R.; Trosko, J.E.; D'Ambrosio, S.M.; Setlow, R.B.

    1978-01-01

    Chinese hamster (V79) cells were irradiated with a fractionated regime of ultraviolet light (UV 1 +UV 2 ). The fractionation of a UV dose always increased the colony-forming ability but reduced (or it did not change) the mutation frequencies. Treatment with cycloheximide between the two UV irradiations resulted in two types of effects, depending on the protocols used. Long exposures to cycloheximide (i.e., >6h) for the entire period between UV 1 and UV 2 or partial treatment of cycloheximide (i.e., 3h) long before UV 2 always resulted in reduced colony-forming ability and enhanced or unchanged mutation frequencies. Exposure to cycloheximide for the entire period in the short fractionated regime (i.e., 4h) between UV 1 and UV 2 or partial treatment of cycloheximide just prior to UV 2 tended to give the opposite effects. Caffeine treatment before UV 2 , with or without UV 1 , significantly increased the mutation frequencies. These results suggest that an error-free postreplication repair system exists in Chinese hamster cells which is inhibitable by particular cycloheximide or caffeine treatments. (Auth.)

  6. Salicylic acid inhibits UV- and Cis-Pt-induced human immunodeficiency virus expression

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Panozzo, J.; Libertin, C.R.; Schreck, S.; South Carolina Univ., Columbia, SC

    1994-01-01

    Previous studies have shown that exposure of HeLa cells stably transfected with a human immunodeficiency virus-long terminal repeat-chloramphenicol acetyl transferase (HIV-LTR-CAT) construct to UV light-induced expression from the HIV LTR. By culturing the cells with salicylic acid we demonstrated dose-dependent repression of this induced HIV expression. Repression was evident if salicylic acid was administered 2 h before, at the same time as, or up to 6 h after exposure to the DNA-damaging agent. The kinetics were similar for UV- and for cis-Pt-induced HIV expression, and induction was dependent on the UV dose or cis-Pt concentration added to the culture. These results suggest a role for the prostaglandins or the cyclooxygenase pathway or both in HIV induction mediated by DNA-damaging agents

  7. The effect of UV and visible light irradiation on the development of microsclerotium of the fungus Macrophomina phaseolina

    International Nuclear Information System (INIS)

    Nagy, P.; Fischl, G.

    2002-01-01

    Macrophomina phaseolina is a poliphagus fungus, which is able to infect numerous host-plant (maize, sunflower, pepper) and causes large yield losses. Our in vitro experiments demonstrate, how different wavelength light irradiation influences the growth of mycelium and the formation of microsclerotium. The habit of cultures treated by blue light and UV radiation changed, the formed microsclerotia had a convenient sharpness for the data evaluation by CCD camera. The mycelium was degraded as a result of UV radiation

  8. Irradiation of skin with visible light induces reactive oxygen species and matrix-degrading enzymes.

    Science.gov (United States)

    Liebel, Frank; Kaur, Simarna; Ruvolo, Eduardo; Kollias, Nikiforos; Southall, Michael D

    2012-07-01

    Daily skin exposure to solar radiation causes cells to produce reactive oxygen species (ROS), which are a primary factor in skin damage. Although the contribution of the UV component to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology. Solar radiation comprises UV, and thus the purpose of this study was to examine the physiological response of skin to visible light (400-700 nm). Irradiation of human skin equivalents with visible light induced production of ROS, proinflammatory cytokines, and matrix metalloproteinase (MMP)-1 expression. Commercially available sunscreens were found to have minimal effects on reducing visible light-induced ROS, suggesting that UVA/UVB sunscreens do not protect the skin from visible light-induced responses. Using clinical models to assess the generation of free radicals from oxidative stress, higher levels of free radical activity were found after visible light exposure. Pretreatment with a photostable UVA/UVB sunscreen containing an antioxidant combination significantly reduced the production of ROS, cytokines, and MMP expression in vitro, and decreased oxidative stress in human subjects after visible light irradiation. Taken together, these findings suggest that other portions of the solar spectrum aside from UV, particularly visible light, may also contribute to signs of premature photoaging in skin.

  9. How UV Light Touches the Brain and Endocrine System Through Skin, and Why.

    Science.gov (United States)

    Slominski, Andrzej T; Zmijewski, Michal A; Plonka, Przemyslaw M; Szaflarski, Jerzy P; Paus, Ralf

    2018-05-01

    The skin, a self-regulating protective barrier organ, is empowered with sensory and computing capabilities to counteract the environmental stressors to maintain and restore disrupted cutaneous homeostasis. These complex functions are coordinated by a cutaneous neuro-endocrine system that also communicates in a bidirectional fashion with the central nervous, endocrine, and immune systems, all acting in concert to control body homeostasis. Although UV energy has played an important role in the origin and evolution of life, UV absorption by the skin not only triggers mechanisms that defend skin integrity and regulate global homeostasis but also induces skin pathology (e.g., cancer, aging, autoimmune responses). These effects are secondary to the transduction of UV electromagnetic energy into chemical, hormonal, and neural signals, defined by the nature of the chromophores and tissue compartments receiving specific UV wavelength. UV radiation can upregulate local neuroendocrine axes, with UVB being markedly more efficient than UVA. The locally induced cytokines, corticotropin-releasing hormone, urocortins, proopiomelanocortin-peptides, enkephalins, or others can be released into circulation to exert systemic effects, including activation of the central hypothalamic-pituitary-adrenal axis, opioidogenic effects, and immunosuppression, independent of vitamin D synthesis. Similar effects are seen after exposure of the eyes and skin to UV, through which UVB activates hypothalamic paraventricular and arcuate nuclei and exerts very rapid stimulatory effects on the brain. Thus, UV touches the brain and central neuroendocrine system to reset body homeostasis. This invites multiple therapeutic applications of UV radiation, for example, in the management of autoimmune and mood disorders, addiction, and obesity.

  10. Der Effekt UV-blockierender Kontaktlinsen bei der Therapie der Keratitis superficialis chronica des Hundes

    OpenAIRE

    Denk, Nora

    2009-01-01

    Objective Canine chronic superficial keratitis (CSK) is chronic, progressive keratopathy, which is suspected to be caused by an immune mediated response triggered by ultraviolet light exposure. The purpose of this study was to evaluate the effect of UV-blocking soft contact lenses in treatment for CSK. Methods 26 dogs (26 eyes) with CSK were treated continuously with UV-blocking contact lenses (*Acri.Pat®-UV bandage lenses) for six months. A contact lens was placed on one eye of eac...

  11. Synthesis and controlled self-assembly of UV-responsive gold nanoparticles in block copolymer templates.

    Science.gov (United States)

    Song, Dong-Po; Wang, Xinyu; Lin, Ying; Watkins, James J

    2014-11-06

    We demonstrate the facile synthesis of gold nanoparticles (GNPs) functionalized by UV-responsive block copolymer ligands, poly(styrene)-b-poly(o-nitrobenzene acrylate)-SH (PS-b-PNBA-SH), followed by their targeted distribution within a lamellae-forming poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer. The multilayer, micelle-like structure of the GNPs consists of a gold core, an inner PNBA layer, and an outer PS layer. The UV-sensitive PNBA segment can be deprotected into a layer containing poly(acrylic acid) (PAA) when exposed to UV light at 365 nm, which enables the simple and precise tuning of GNP surface properties from hydrophobic to amphiphilic. The GNPs bearing ligands of different chemical compositions were successfully and selectively incorporated into the PS-b-P2VP block copolymer, and UV light showed a profound influence on the spatial distributions of GNPs. Prior to UV exposure, GNPs partition along the interfaces of PS and P2VP domains, while the UV-treated GNPs are incorporated into P2VP domains as a result of hydrogen bond interactions between PAA on the gold surface and P2VP domains. This provides an easy way of controlling the arrangement of nanoparticles in polymer matrices by tailoring the nanoparticle surface using UV light.

  12. Characterization and photocatalytic performance evaluation of various metal ion-doped microstructured TiO2 under UV and visible light.

    Science.gov (United States)

    Sahoo, Chittaranjan; Gupta, Ashok K

    2015-01-01

    Commercially available microcrystalline TiO2 was doped with silver, ferrous and ferric ion (1.0 mol %) using silver nitrate, ferrous sulfate and ferric nitrate solutions following the liquid impregnation technology. The catalysts prepared were characterised by FESEM, XRD, FTIR, DRS, particle size and micropore analysis. The photocatalytic activity of the prepared catalysts was tested on the degradation of two model dyes, methylene blue (3,7-bis (Dimethylamino)-phenothiazin-5-ium chloride, a cationic thiazine dye) and methyl blue (disodium;4-[4-[[4-(4-sulfonatoanilino)phenyl]-[4-(4-sulfonatophenyl)azaniumylidenecyclohexa-2,5-dien-1-ylidene]methyl]anilino]benzene sulfonate, an anionic triphenyl methane dye) under irradiation by UV and visible light in a batch reactor. The efficiency of the photocatalysts under UV and visible light was compared to ascertain the light range for effective utilization. The catalysts were found to have the anatase crystalline structure and their particle size is in a range of 140-250 nm. In the case of Fe(2+) doped TiO2 and Fe(3+) doped TiO2, there was a greater shift in the optical absorption towards the visible range. Under UV light, Ag(+) doped TiO2 was the most efficient catalyst and the corresponding decolorization was more than 99% for both the dyes. Under visible light, Fe(3+) doped TiO2 was the most efficient photocatalyst with more than 96% and 90% decolorization for methylene blue and methyl blue, respectively. The kinetics of the reaction under both UV and visible light was investigated using the Langmuir-Hinshelwood pseudo-first-order kinetic model. Kinetic measurements confirmed that, Ag(+) doped TiO2 was most efficient in the UV range, while Fe(3+) doped TiO2 was most efficient in the visible range.

  13. 'In vitro' studies on the interaction of rickettsia and macrophages. I. Effect of ultraviolet light on 'Coxiella burnetii' inactivation and macrophage enzymes: uv-inactivated 'C. burnetii'/macrophage enzymes. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Little, J.S.; Kishimoto, R.A.; Canonico, P.G.

    1979-09-04

    The inactivation of Coxiella burnetii in suspension or in cultures of guinea pig peritoneal macrophages by ultraviolet (UV) light was studied. The effect of UV treatment on the activity of macrophage organelle marker enzymes and their subsequent equilibration in linear sucrose gradients was also determined. It was shown that UV treatment of 600 microwatts/sq cm for 15 sec at a distance of 10 cm inactivated C. burnetii, either in suspension (10 to the 8th power organisms/ML) or within guinea pig peritoneal macrophages. Similar UV treatment had little effect on the activity or equilibration of macrophage organelle marker enzymes in linear sucrose gradients. However, longer exposure caused considerable inactivatioin of these enzymes.

  14. 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)

    Olsson, L.C.; Veit, M.; Bornman, J.F.

    1999-01-01

    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

  15. Impact assessment of energy-efficient lighting in patients with lupus erythematosus: a pilot study.

    Science.gov (United States)

    Fenton, L; Dawe, R; Ibbotson, S; Ferguson, J; Silburn, S; Moseley, H

    2014-03-01

    Patients with lupus erythematosus (LE) are often abnormally photosensitive. Ultraviolet (UV) exposure can not only induce cutaneous lesions but may also contribute to systemic flares and disease progression. Various forms of energy-efficient lighting have been shown to emit UV radiation. To determine the effects of these emissions on individuals with LE. This assessment investigated cutaneous responses to repeated exposures from three types of lighting: compact fluorescent lamp (CFL), light-emitting diode (LED) and energy-efficient halogen (EEH). The subjects were 15 patients with LE and a control group of five healthy volunteers. No cutaneous LE lesions were induced by any of the light sources. Delayed skin erythema was induced at the site of CFL irradiation in six of the 15 patients with LE and two of the five healthy subjects. Erythema was increased in severity and more persistent in patients with LE. One patient with LE produced a positive delayed erythema to the EEH. A single patient with LE produced immediate abnormal erythemal responses to the CFL, LED and EEH. Further investigation revealed that this patient also had solar urticaria. All other subjects had negative responses to LED exposure. Compact fluorescent lamps emit UV that can induce skin erythema in both individuals with LE and healthy individuals when situated in close proximity. However, this occurs to a greater extent and is more persistent in patients with LE. EEHs emit UVA that can induce erythema in patients with LE. LEDs provide a safer alternative light source without risk of UV exposure. © 2013 British Association of Dermatologists.

  16. Near Infrared Photoimmunotherapy with Combined Exposure of External and Interstitial Light Sources.

    Science.gov (United States)

    Maruoka, Yasuhiro; Nagaya, Tadanobu; Sato, Kazuhide; Ogata, Fusa; Okuyama, Shuhei; Choyke, Peter L; Kobayashi, Hisataka

    2018-02-21

    Near infrared photoimmunotherapy (NIR-PIT) is a new target-cell-specific cancer treatment that induces highly selective necrotic/immunogenic cell death after systemic administration of a photoabsorber antibody conjugate and subsequent NIR light exposure. However, the depth of NIR light penetration in tissue (approximately 2 cm) with external light sources limits the therapeutic effects of NIR-PIT. Interstitial light exposure using cylindrical diffusing optical fibers can overcome this limitation. The purpose in this study was to compare three NIR light delivery methods for treating tumors with NIR-PIT using a NIR laser system at an identical light energy; external exposure alone, interstitial exposure alone, and the combination. Panitumumab conjugated with the photoabsorber IRDye-700DX (pan-IR700) was intravenously administered to mice with A431-luc xenografts which are epithelial growth factor receptor (EGFR) positive. One and 2 days later, NIR light was administered to the tumors using one of three methods. Interstitial exposure alone and in combination with external sources showed the greatest decrease in bioluminescence signal intensity. Additionally, the combination of external and interstitial NIR light exposure showed significantly greater tumor size reduction and prolonged survival after NIR-PIT compared to external exposure alone. This result suggested that the combination of external and interstitial NIR light exposure was more effective than externally applied light alone. Although external exposure is the least invasive means of delivering light, the combination of external and interstitial exposures produces superior therapeutic efficacy in tumors greater than 2 cm in depth from the tissue surface.

  17. Role of UV light in photodamage, skin aging, and skin cancer: importance of photoprotection.

    Science.gov (United States)

    Gonzaga, Evelyn R

    2009-01-01

    Solar, and particularly UV, radiation causes molecular and cellular damage with resultant histopathologic and clinical degenerative changes, leading in turn to photosensitivity, photo-aging, and skin cancer. While our bodies have some natural UV defenses, additional protection from the sun is essential, including sun avoidance, physical protection, and sunscreen use. Sun avoidance includes limiting exposure during peak UV times (10am-4pm), avoiding UV-reflective surfaces such as sand, snow and water, and eliminating photosensitizing drugs. Physical protection includes wearing photoprotective clothing such as a broad-brimmed hat and long sleeves and use of UV-blocking films on windows. Sunscreen containing avobenzone, titanium dioxide, zinc oxide or encamsule should be used daily and frequently reapplied. To guard against the UVB spectrum, zinc oxide and titanium dioxide are particularly recommended. Sunscreen is generally under-applied at only 25% of the recommended dose, seriously compromising photoprotection. Dosage guidelines recommend using more than half a teaspoon each on head and neck area and each arm, and more than a teaspoon each on anterior torso, posterior torso, and each leg (approximately 2 mg/cm(2)).

  18. Listeria monocytogenes survival of UV-C radiation is enhanced by presence of sodium chloride, organic food material and by bacterial biofilm formation

    DEFF Research Database (Denmark)

    Bernbom, Nete; Vogel, Birte Fonnesbech; Gram, Lone

    2011-01-01

    The bactericidal effect on food processing surfaces of ceiling-mounted UV-C light (wavelength 254nm) was determined in a fish smoke house after the routine cleaning and disinfection procedure. The total aerobic counts were reduced during UV-C light exposure (48h) and the number of Listeria...... and that it, as all disinfecting procedures, is hampered by the presence of organic material....

  19. Towards an electronic nose based on nano-structured transition metal oxides activated by a tuneable UV light source

    CSIR Research Space (South Africa)

    Mwakikunga, B

    2011-10-01

    Full Text Available Traditional gas sensors involve heating the sensor material for gas selectivity. New gas approaches require activation by a broadband UV light source. The authors propose to employ a tuneable UV source in which this source is tuned for its many...

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

    International Nuclear Information System (INIS)

    Haapala, Jaana K.; Moersky, Sami K.; Saarnio, Sanna; Suokanerva, Hanne; Kyroe, Esko; Silvola, Jouko; Holopainen, Toini

    2010-01-01

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

  1. Exposure to Non-Extreme Solar UV Daylight: Spectral Characterization, Effects on Skin and Photoprotection

    OpenAIRE

    Marionnet, Claire; Tricaud, Caroline; Bernerd, Fran?oise

    2014-01-01

    The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320–400 nm and UVB, 280–320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinic...

  2. Health hazards of UV radiation

    International Nuclear Information System (INIS)

    Matthes, R.

    1994-01-01

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

  3. Carotenoids quench evolution of excited species in epidermis exposed to UV-B (290-320 nm) light

    International Nuclear Information System (INIS)

    Mathews-Roth, M.M.

    1986-01-01

    Reactions involving singlet oxygen and other free radicals have been identified in epidermis containing either exogenous or endogenous photosensitizers, soaked in a singlet oxygen/free radical trap, and then exposed to visible or UV-A (320-400 nm) light. Such reactions can be quenched by the presence of the carotenoid pigments β-carotene and canthaxanthin which accumulate in epidermis after oral administration. It is reported that the carotenoid pigments β-carotene, canthaxanthin and phytoene accumulating in epidermis can also quench to some degree those photochemical reactions involving singlet oxygen and free radicals that occur when epidermis is exposed to the sunburn spectrum of light (UV-B, 290-320 nm). (author)

  4. Photocatalytic activity of attapulgite–BiOCl–TiO2 toward degradation of methyl orange under UV and visible light irradiation

    International Nuclear Information System (INIS)

    Zhang, Lili; Zhang, Jiahui; Zhang, Weiguang; Liu, Jianquan; Zhong, Hui; Zhao, Yijiang

    2015-01-01

    Highlights: • Excellent photocatalyst was obtained by introducing BiOCl–TiO 2 onto attapulgite. • 100 mg L −1 methyl orange (MO) was totally decomposed under UV light within 70 min. • 92.6% of 10 mg L −1 MO was decomposed within 120 min under visible light. • ATT–BiOCl–TiO 2 show better activity than P 25 especially under visible light. • Mechanism of photocatalytic activity enhancement was identified. - Abstract: An environmental friendly composite photocatalyst with efficient UV and visible light activity has been synthesized by introducing BiOCl–TiO 2 hybrid oxide onto the surface of attapulgite (ATT) (denoted as ATT–BiOCl–TiO 2 ), using a simple in situ depositing technique. The obtained products were characterized by XRD, TEM, BET and UV–vis diffuse reflectance spectra measurements. Results showed that BiOCl–TiO 2 composite particles were successfully loaded onto attapulgite fibers' surface without obvious aggregation. The photocatalytic activity of ATT–BiOCl–TiO 2 was investigated by degradation of methyl orange under UV and visible light irradiation. It was found that 100 mg L −1 methyl orange was totally decomposed under UV light within 70 min and 92.57% of 10 mg L −1 methyl orange was decomposed under visible light within 120 min using ATT–BiOCl–TiO 2 as photocatalyst. These results were quite better than that of P 25 , especially under visible light irradiation. Possible mechanism for the enhancement was proposed

  5. Shining light on skin pigmentation: the darker and the brighter side of effects of UV radiation.

    Science.gov (United States)

    Maddodi, Nityanand; Jayanthy, Ashika; Setaluri, Vijayasaradhi

    2012-01-01

    The term barrier function as applied to human skin often connotes the physical properties of this organ that provides protection from its surrounding environment. This term does not generally include skin pigmentation. However, skin pigmentation, which is the result of melanin produced in melanocytes residing in the basal layer of the skin and exported to the keratinocytes in the upper layers, serves equally important protective function. Indeed, changes in skin pigmentation are often the most readily recognized indicators of exposure of skin to damaging agents, especially to natural and artificial radiation in the environment. Several recent studies have shed new light on (1) the mechanisms involved in selective effects of subcomponents of UV radiation on human skin pigmentation and (2) the interactive influences between keratinocytes and melanocytes, acting as "epidermal melanin unit," that manifest as changes in skin pigmentation in response to exposure to various forms of radiation. This article provides a concise review of our current understanding of the effects of the nonionizing solar radiation, at cellular and molecular levels, on human skin pigmentation. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  6. Acute cataract in the rat after exposure to radiation in the 300 nm wavelength region

    International Nuclear Information System (INIS)

    Soederberg, P.G.

    1988-01-01

    Experimental and epidemiological data indicate a correlation between exposure to UV radiation and cataract morbidity. UV radiation induced cataract is thought to be evoked by photochemical mechanisms. The present investigation resolves the macroscopical events in the rat lens after a one dose exposure to spectrally and radiometrically well defined UV radiation, as revealed in light- and dark-field illumination. The macroscopic sequence of events is related to the morphology as revealed by light- and electron microscopy. The radiation was found to alter the chromation pattern and to induce morphological changes indicating a disturbance of the cellular water balance. The latter is assumed to cause the acute UV radiation induced opacification of the lens. It is suggested that future investigations of the toxic effects of UV radiation in the lens should focus on how UV radiation effects the chromatin and the cellular water balance. (author)

  7. Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens.

    Science.gov (United States)

    Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun; Kang, Dong-Hyun

    2016-01-01

    Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm(2). At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Sacrificial hydrogen generation from aqueous triethanolamine with Eosin Y-sensitized Pt/TiO2 photocatalyst in UV, visible and solar light irradiation.

    Science.gov (United States)

    Chowdhury, Pankaj; Gomaa, Hassan; Ray, Ajay K

    2015-02-01

    In this paper, we have studied Eosin Y-sensitized sacrificial hydrogen generation with triethanolamine as electron donor in UV, visible, and solar light irradiation. Aeroxide TiO2 was loaded with platinum metal via solar photo-deposition method to reduce the electron hole recombination process. Photocatalytic sacrificial hydrogen generation was influenced by several factors such as platinum loading (wt%) on TiO2, solution pH, Eosin Y to Pt/TiO2 mass ratio, triethanolamine concentration, and light (UV, visible and solar) intensities. Detailed reaction mechanisms in visible and solar light irradiation were established. Oxidation of triethanolamine and formaldehyde formation was correlated with hydrogen generation in both visible and solar lights. Hydrogen generation kinetics followed a Langmuir-type isotherm with reaction rate constant and adsorption constant of 6.77×10(-6) mol min(-1) and 14.45 M(-1), respectively. Sacrificial hydrogen generation and charge recombination processes were studied as a function of light intensities. Apparent quantum yields (QYs) were compared for UV, visible, and solar light at four different light intensities. Highest QYs were attained at lower light intensity because of trivial charge recombination. At 30 mW cm(-2) we achieved QYs of 10.82%, 12.23% and 11.33% in UV, visible and solar light respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Elodea nuttallii exposure to mercury exposure under enhanced ultraviolet radiation: Effects on bioaccumulation, transcriptome, pigment content and oxidative stress

    International Nuclear Information System (INIS)

    Regier, Nicole; Beauvais-Flück, Rebecca; Slaveykova, Vera I.; Cosio, Claudia

    2016-01-01

    Highlights: • Exposure to UV radiation does not result in co-tolerance to Hg in Elodea nuttallii. • UV radiation increased the stress response to Hg at the transcriptome level. • UV + Hg dysregulated genes of energy and lipid metabolism, nutrition and redox homeostasis. • UV + Hg treatment decreases Hg accumulation in E. nuttallii shoots. • Hg accumulation depends on UV effects on plant metabolism and Hg bioavailability. - Abstract: The hypothesis that increased UV radiation result in co-tolerance to Hg toxicity in aquatic plants was studied at the physiological and transcriptomic level in Elodea nuttallii. At the transcriptomic level, combined exposure to UV + Hg enhanced the stress response in comparison with single treatments, affecting the expression level of transcripts involved in energy metabolism, lipid metabolism, nutrition, and redox homeostasis. Single and combined UV and Hg treatments dysregulated different genes but with similar functions, suggesting a fine regulation of the plant to stresses triggered by Hg, UV and their combination but lack of co-tolerance. At the physiological level, UV + Hg treatment reduced chlorophyll content and depleted antioxidative compounds such as anthocyanin and GSH/GSSG in E. nuttallii. Nonetheless, combined exposure to UV + Hg resulted in about 30% reduction of Hg accumulation into shoots vs exposure to Hg alone, which was congruent with the level of expression of several transporter genes, as well as the UV effect on Hg bioavailability in water. The findings of the present work underlined the importance of performing experimentation under environmentally realistic conditions and to consider the interplay between contaminants and environmental variables such as light that might have confounding effects to better understand and anticipate the effects of multiple stressors in aquatic environment.

  10. Elodea nuttallii exposure to mercury exposure under enhanced ultraviolet radiation: Effects on bioaccumulation, transcriptome, pigment content and oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Regier, Nicole; Beauvais-Flück, Rebecca; Slaveykova, Vera I.; Cosio, Claudia, E-mail: Claudia.Cosio@unige.ch

    2016-11-15

    Highlights: • Exposure to UV radiation does not result in co-tolerance to Hg in Elodea nuttallii. • UV radiation increased the stress response to Hg at the transcriptome level. • UV + Hg dysregulated genes of energy and lipid metabolism, nutrition and redox homeostasis. • UV + Hg treatment decreases Hg accumulation in E. nuttallii shoots. • Hg accumulation depends on UV effects on plant metabolism and Hg bioavailability. - Abstract: The hypothesis that increased UV radiation result in co-tolerance to Hg toxicity in aquatic plants was studied at the physiological and transcriptomic level in Elodea nuttallii. At the transcriptomic level, combined exposure to UV + Hg enhanced the stress response in comparison with single treatments, affecting the expression level of transcripts involved in energy metabolism, lipid metabolism, nutrition, and redox homeostasis. Single and combined UV and Hg treatments dysregulated different genes but with similar functions, suggesting a fine regulation of the plant to stresses triggered by Hg, UV and their combination but lack of co-tolerance. At the physiological level, UV + Hg treatment reduced chlorophyll content and depleted antioxidative compounds such as anthocyanin and GSH/GSSG in E. nuttallii. Nonetheless, combined exposure to UV + Hg resulted in about 30% reduction of Hg accumulation into shoots vs exposure to Hg alone, which was congruent with the level of expression of several transporter genes, as well as the UV effect on Hg bioavailability in water. The findings of the present work underlined the importance of performing experimentation under environmentally realistic conditions and to consider the interplay between contaminants and environmental variables such as light that might have confounding effects to better understand and anticipate the effects of multiple stressors in aquatic environment.

  11. Dosimetric UV Exposure Effect on the Optical Properties of Ag2O Doped P2O5-ZnO-CuO Glass

    Directory of Open Access Journals (Sweden)

    K. S. Al Mugren

    2016-01-01

    Full Text Available Silver phosphate glass types within composition 60P2O5-30ZnO-10CuO-100000 ppm Ag2O were prepared by melt-quenching technique. The optical properties of these glass types were studied under UV exposure at different times, 0, 20, 80, 105, and 115 minutes. The optical absorbance spectra were measured in the range of wavelength from 190 to 3200 nm. The absorbance bandwidth decreases with increasing the time of UV exposure. The optical energy gap, Eg, linear refractive index, n, ratio between molar refraction, Rm, and molar volume, Vm, and metallization criterion (M were estimated. The value of Eg decreases from 2.132 to 1.91 eV with increasing the time of UV exposure from 0 to 115 min. Otherwise n value and metallization increase with increase in the time of UV exposure. The results indicated that these glass types are promising for using an ultraviolet radiation dosimeter.

  12. Absence of photoreactivation of pyrimidine dimers in the epidermis of hairless mice following exposures to ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

    Ley, R D; Sedita, B A; Grube, D D

    1978-01-01

    The influence of photoreactivating light on the fate of uv-induced DNA damage has been measured in the epidermis of hairless mice using damage-specific endonuclease from Micrococcus luteus. Groups of mice were exposed to varying fluences of uv at 297 nm or from an FS40 fluorescent sun lamp to induce uv photoproducts. The same fluence-dependent DNA damage was observed in high molecular weight epidermal DNA regardless of whether the mice were killed immediately, or maintained in the dark or under photorectivating light for 20 h after uv. Thus, no detectable photoreactivation of uv-induced pyrimidine dimers could be demonstrated in mouse epithelial cells in vivo.

  13. The reduction of retinal autofluorescence caused by light exposure.

    Science.gov (United States)

    Morgan, Jessica I W; Hunter, Jennifer J; Merigan, William H; Williams, David R

    2009-12-01

    A prior study showed that long exposure to 568-nm light at levels below the maximum permissible exposure safety limit produces retinal damage preceded by a transient reduction in the autofluorescence of retinal pigment epithelial (RPE) cells in vivo. The present study shows how the effects of exposure power and duration combine to produce this autofluorescence reduction and find the minimum exposure causing a detectable autofluorescence reduction. Macaque retinas were imaged using a fluorescence adaptive optics scanning laser ophthalmoscope to resolve individual RPE cells in vivo. The retina was exposed to 568-nm light over a square subtending 0.5 degrees with energies ranging from 1 to 788 J/cm(2), where power and duration were independently varied. In vivo exposures of 5 J/cm(2) and higher caused an immediate decrease in autofluorescence followed by either full autofluorescence recovery (exposures or= 247 J/cm(2)). No significant autofluorescence reduction was observed for exposures of 2 J/cm(2) and lower. Reciprocity of exposure power and duration held for the exposures tested, implying that the total energy delivered to the retina, rather than its distribution in time, determines the amount of autofluorescence reduction. That reciprocity held is consistent with a photochemical origin, which may or may not cause retinal degeneration. The implementation of safe methods for delivering light to the retina requires a better understanding of the mechanism causing autofluorescence reduction. Finally, RPE imaging was demonstrated using light levels that do not cause a detectable reduction in autofluorescence.

  14. Recovery from DNA synthesis in V 79 chinese hamster cells irradiated with UV light

    International Nuclear Information System (INIS)

    Ventura, A.M.

    1987-01-01

    Mammalian cells recover from DNA synthesis inhibition by UV light before most of the pyrimidine dimers have been removed from the genome. Most of the rodent cells show a deficient dimer excision repair compared with normal human fibroblasts. Despite this fact they recover efficiently from DNA synthesis inhibition after UV. In Chinese hamster V 79 cells was found that this recovery takes place in the absence of a significant excision repair, and it seems to be directly coupled to a recovery in the rate of movement of the replication fork. 120 refs, 31 figs. (author)

  15. Loss of photoreversibility for UV mutation in E. coli using 405 nm or near-UV challenge

    International Nuclear Information System (INIS)

    Kristoff, S.; Bockrath, R.

    1983-01-01

    E. coli mutagenized with germicidal ultraviolet light (UV) were incubated to allow for development of mutation-fixation processes. Fixation was estimated from the effects on mutation frequency of photoreactivation challenge during the first 60 min post-UV. Two different light sources were used for photoreactivation, one providing effective light primarily at 405 nm and another providing a broad range of near-UV around 365 nm. Kinetics for the loss of photoreversibility (LOP) were determined. The times for completion of LOP in wild-type cells indicated one fixation process for back mutation and another for de novo or converted suppressor mutation regardless of the light source. Using 405-nm light for photoreactivation, the LOP kinetics for back mutation and de novo suppressor mutation in uvrA cells were similar. Hence, classical observations were confirmed here. Immediately post-UV all mutation frequencies were more sensitive to near-UV than 405-nm light. (orig./AJ)

  16. UV and hydrogen peroxide treatment restores changes in innate immunity caused by exposure of fish to reuse water.

    Science.gov (United States)

    Singh, Arvinder; Havixbeck, Jeffrey J; Smith, Matthew K; Shu, Zengquan; Tierney, Keith B; Barreda, Daniel R; El-Din, Mohamed Gamal; Belosevic, Miodrag

    2015-03-15

    The purpose of this study was to assess the innate immunity of goldfish exposed to reuse water, and UV/H2O2-treated reuse water, using a real-time flow-through exposure system. The reuse water generated by ultrafiltration of finished wastewater from the municipal wastewater treatment plant was analyzed for the presence of a panel of 20 herbicides/fungicides and 46 pharmaceuticals and personal care products (PPCP). There was a seasonal variation in the profile and concentrations of xenobiotics in reuse water with lowest levels occurring in the summer. The innate immunity parameters assessed were cytokine (IFNγ, IL-1β, IL-10, TNFα2), and cytokine receptor (TNFR1, TNFR2, IFNGR1, IFNGR2) gene expression, and phagocytosis of kidney leukocyte subpopulations. Assessment of innate immunity parameters was done after acute (7 days) and sub chronic (30 and 60 days) exposure to reuse water, UV/H2O2-treated reuse water, and activated carbon-treated reuse water (ACT; control), during spring, summer and fall of 2012. Temporal (acute versus sub chronic) as well as seasonal differences in innate immunity of fish exposed to reuse water were observed. The acute exposure of fish to reuse water caused significant down-regulation in cytokine gene expression in different organs of fish (kidney, spleen, liver) and phagocytic ability of different kidney leukocyte subpopulations. The immune gene expression and phagocytosis of kidney leukocytes of fish returned to ACT control levels after sub chronic exposure suggesting that fish have habituated to the reuse water exposure. The changes in gene expression after acute exposure were related to variations in the profile of xenobiotics in reuse water during different seasons. The efficiency of xenobiotic removal using UV/H2O2 ranged between 1.6 and 100% indicating that treatment of reuse water using high dose UV/H2O2 was only partially effective in removing the xenobiotics, as assessed by both chemical analyses and measurement of innate immune

  17. The mechanisms of UV mutagenesis

    International Nuclear Information System (INIS)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

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

  18. Study on DNA damages induced by UV radiation

    International Nuclear Information System (INIS)

    Doan Hong Van; Dinh Ba Tuan; Tran Tuan Anh; Nguyen Thuy Ngan; Ta Bich Thuan; Vo Thi Thuong Lan; Tran Minh Quynh; Nguyen Thi Thom

    2015-01-01

    DNA damages in Escherichia coli (E. coli) exposed to UV radiation have been investigated. After 30 min of exposure to UV radiation of 5 mJ/cm"2, the growth of E. coli in LB broth medium was about only 10% in compared with non-irradiated one. This results suggested that the UV radiation caused the damages for E. coli genome resulted in reduction in its growth and survival, and those lesions can be somewhat recovered. For both solutions of plasmid DNAs and E. coli cells containing plasmid DNA, this dose also caused the breakage on single and double strands of DNA, shifted the morphology of DNA plasmid from supercoiled to circular and linear forms. The formation of pyrimidine dimers upon UV radiation significantly reduced when the DNA was irradiated in the presence of Ganoderma lucidum extract. Thus, studies on UV-induced DNA damage at molecular level are very essential to determine the UV radiation doses corresponding to the DNA damages, especially for creation and selection of useful radiation-induced mutants, as well as elucidation the protective effects of the specific compounds against UV light. (author)

  19. Experimental photoimmunology: immunologic ramifications of UV-induced carcinogenesis

    International Nuclear Information System (INIS)

    Daynes, R.A.; Bernhard, E.J.; Gurish, M.F.; Lynch, D.H.

    1981-01-01

    The use of animal model systems to investigate the sequence of events which lead to the induction and progression of skin tumors following chronic ultraviolet light (UVL) exposure has clearly shown that the direct mutagenic effects of UVL is only one of the components involved in this process. In spite of the fact that overt carcinogenesis is only one of the many effects produced by UV light, most hypotheses as to the mechanism by which UVL can cause the mutations necessary to achieve the transformed phenotype have focused on the direct effects of UVL on DNA and the generation of carcinogenic compounds. Investigations during the last 5 yr, however, have clearly demonstrated that immunologic factors are also critically important in the pathogenesis of UV-induced skin cancers. A complete understanding of UV-carcinogenesis must therefore consider the mechanisms which allow the transformed cell to evade immunologic rejection by the host in addition to those aspects which deal with conversion of a normal cell to a cancer cell. It is the object of this review to provide both a historical account of the work which established the immunologic consequences of chronic UVL exposure and the results of recent experiments designed to investigate the kinetics and mechanisms by which UVL affects the immunologic apparatus. In addition, a hypothetical model is presented to explain the sequence of events which ultimately lead to the emergence of the suppressor T-cells which regulate antitumor immune responses

  20. Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bhuvaneshwari, M.; Iswarya, V. [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Archanaa, S. [Department of Biotechnology, IIT Madras (India); Madhu, G.M. [Department of Chemical Engineering, M.S. Ramaiah Institute of Technology, Bangalore (India); Kumar, G.K. Suraish [Department of Biotechnology, IIT Madras (India); Nagarajan, R. [Department of Chemical Engineering, IIT Madras (India); Chandrasekaran, N. [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India)

    2015-05-15

    Highlights: • The cytotoxicity of ZnO NPs with two hydrodynamic sizes towards freshwater algae. • Size dependent toxicity under UV-C, dark and visible light conditions. • Cytotoxicity principally due to ZnO NPs not the released Zn{sup 2+} ions. • The internalization of ZnO NPs leads to membrane damage and ROS production. - Abstract: Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5 ± 2.55 nm for ZnO-1 NPs and 616.2 ± 38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn{sup 2+} ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses.

  1. Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions

    International Nuclear Information System (INIS)

    Bhuvaneshwari, M.; Iswarya, V.; Archanaa, S.; Madhu, G.M.; Kumar, G.K. Suraish; Nagarajan, R.; Chandrasekaran, N.; Mukherjee, Amitava

    2015-01-01

    Highlights: • The cytotoxicity of ZnO NPs with two hydrodynamic sizes towards freshwater algae. • Size dependent toxicity under UV-C, dark and visible light conditions. • Cytotoxicity principally due to ZnO NPs not the released Zn 2+ ions. • The internalization of ZnO NPs leads to membrane damage and ROS production. - Abstract: Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5 ± 2.55 nm for ZnO-1 NPs and 616.2 ± 38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn 2+ ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses

  2. Knowledge of outdoor workers on the effects of natural UV radiation and methods of protection against exposure.

    Science.gov (United States)

    Hault, K; Rönsch, H; Beissert, S; Knuschke, P; Bauer, A

    2016-04-01

    The most important but influenceable risk factor in the development of skin cancer is the unprotected exposure to solar ultraviolet (UV) radiation. In order to assure adequate and effective protection against UV exposure, a level of knowledge about solar radiation and its effects is required. The objective of this study was to assess the knowledge of workers in outdoor professions on the effects of natural UV radiation and methods of protection against exposure. Forty outdoor workers were given a standardized questionnaire designed to ascertain their level of knowledge. The majority of participants knew exposure to solar radiation can be detrimental depending on exposure time. Eighty-three percentage recognized that people working regularly in an outdoor environment may be at risk due to high exposure. Long-sleeved clothing plus headgear and sunscreen containing sun-protecting substances were deemed adequate methods of protection by 83% and 85% respectively. Seventy percentage of the outdoor workers were familiar with the definition of the sun protection factor (SPF), yet only 25% correctly identified the amount of sunscreen needed to achieve the SPF as indicated on the product. A mere 8% of participants knew that symptoms of a sunburn first became apparent 3 h after sun exposure and only 18% were able to accurately gauge the amount of time they could spend in the sun before developing one. Although 30% had heard of the ultraviolet index (UVI), only 13% understood that protecting your skin using additional measures is recommended as of UVI 3. Overall, 30% of the outdoor workers thought themselves sufficiently protected against the harmful effects of the sun. While the participants of this study had a basic fundamental understanding of the effects of solar radiation and methods of protection against exposure, there remains an urgent need for further clarification across all demographic groups. © 2016 European Academy of Dermatology and Venereology.

  3. Photostability of cosmetic UV filters on mammalian skin under UV exposure.

    Science.gov (United States)

    Stiefel, Constanze; Schwack, Wolfgang; Nguyen, Yen-Thi Hai

    2015-01-01

    Previous studies showed that the common UV filter substances benzophenone-3 (BP-3), butyl methoxydibenzoylmethane (BM-DBM), octocrylene (OCR), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (EHS) and ethylhexyl triazone (EHT) were able to react with amino side chains of different proteins in vitro. To transfer the results to mammalian skin conditions, sunscreen products were applied on both prepared fresh porcine skin and glass plates, followed by UV irradiation and the determination of depletion of the respective UV filters. Significantly lower recoveries of the UV filters extracted from skin samples than from glass plates indicated the additional reaction of the UV filters with skin constituents, when proteins will be the most important reactants. Among the products tested, BP-3 showed the greatest differences in recoveries between glass and skin samples of about 13% and 24% after 2 and 4 h of irradiation, respectively, followed by EHS > BM-DBM > OCR > EHMC > EHT. The obtained results raise the question, whether the common in vitro evaluations of sunscreens, using inert substrate materials like roughened quartz or polymethyl methacrylate (PMMA) plates are really suitable to fully replace in vivo methods, as they cannot include skin-typical reactions. © 2014 The American Society of Photobiology.

  4. Antibodies to uv light denatured DNA in systemic lupus erythematosus: detection by filter radioimmunoassay and clinical correlations

    Energy Technology Data Exchange (ETDEWEB)

    Davis, P; Russell, A S; Percy, J S

    1976-12-01

    Antibodies to ultraviolet light denatured DNA (UV DNA) have been measured in patients with systemic lupus erythematosus (SLE) and normal subjects, using a millipore filter radioimmunoassay. High levels of UV DNA binding were only found in patients with SLE. The presence of UV DNA antibodies correlated well with the presence of native DNA antibodies, although immunodiffusion studies and inhibition techniques showed these antibodies to be immunologically distinct in many cases. Forty-one percent of the SLE patients had had photosensitivity at some stage of their disease, but there was a poor correlation between this symptom and the presence of UV DNA antibodies. Although UV DNA is known to be a potent immunogen, none of the results from this study suggests that antibodies to UV DNA are more than another example of the broad spectrum of antinuclear antibodies seen in SLE.

  5. Protective effects of polyamines against UV-A and UV-B illumination in Physcia semipinnata thalli

    Directory of Open Access Journals (Sweden)

    Esmer Işıl

    2017-04-01

    Full Text Available The damage to DNA induced by UV-A and UV-B and protective effects of the polyamines putrescine (put, spermidine (spd and spermine (spm were investigated on the lichen Physcia semipinnata in the present study. Our results suggest that significant alterations of the photosynthetic quantum yield ratio occurred in response to increased UV-A and UV-B exposure time. The photosynthetic quantum yield ratio gradually decreased in P. semipinnata following exposure to UV-A and UV-B. Physcia semipinnata thalli which were treated with a polyamine in a concentration of 1 mM were not affected by UV-A exposure for 72 h. In the case of UV-B treatment, the protective polyamine dosage was 0.25 mM. We also used the random amplified polymorphic DNA (RAPD technique to detect DNA damage. The main changes observed in the RAPD profiles, which were obtained using 12 RAPD primers, were the appearance or disappearance of different bands and variation of their intensities. The use of at least three different primers allowed detection of specific band patterns in both UV-A- and UV-B-exposed samples treated with polyamines as compared to untreated ones.

  6. Evidence for dark repair of far ultraviolet light damage in the blue-green alga, Gloeocapsa alpicola

    International Nuclear Information System (INIS)

    Williams, E.; Lambert, J.; O'Brien, P.; Houghton, J.A.

    1979-01-01

    The inactivating effect of far UV light on the unicellular blue-green alga Gloeocapsa alpicola could be totally reversed by exposure to blue light immediately after irradiation. However, if the irradiated cells were held in the dark before exposure to blue light, reversal became progressively less efficient, and almost disappeared after 60-80 h holding. Caffeine and acriflavine inhibited loss of photoreversibility, suggesting an involvement of excision functions. Chloramphenicol and rifampicin slightly increased the rate of loss of photoreversibility, indicating that inducible functions play only a minor role. Split UV dose experiments indicated that light-dependent repair remained operational during dark liquid holding. These results provide preliminary evidence for dark repair in G. alpicola. (author)

  7. 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)

  8. UV Light-Assisted Synthesis of Highly Efficient Pd-Based Catalyst over NiO for Hydrogenation of o-Chloronitrobenzene.

    Science.gov (United States)

    Jiang, Weidong; Xu, Bin; Fan, Guangyin; Zhang, Kaiming; Xiang, Zhen; Liu, Xiaoqiang

    2018-04-14

    Supported Pd-based catalyst over active nickel oxide (NiO) was repared using the impregnation method companying with UV-light irradiation. Moreover, the catalytic performance of the obtained Pd-based catalysts was evaluated towards the hydrogenation of o -chloronitrobenzene ( o -CNB). Observations indicate that the as-prepared UV-irradiated Pd/NiO catalyst with a mole fraction 0.2% (0.2%Pd/NiO) has higher activity and selectivity in the o -CNB hydrogenation. Especially, UV-light irradiation played a positive role in the improvement of catalytic activity of 0.2%Pd/NiO catalyst, exhibiting an excess 11-fold activity superiority in contrast with non-UV-irradiated 0.2%Pd/NiO catalyst. In addition, it was investigated that effects of varied factors (i.e., reaction time, temperature, o -CNB/Pd ratio, Pd loading, hydrogen pressure) on the selective hydrogenation of ο -CNB catalyzed by UV-irradiated 0.2%Pd/NiO catalyst. Under the reaction conditions of 60 °C, 0.5 h, 1 MPa H₂ pressure, 100% conversion of o -CNB, and 81.1% o -CAN selectivity were obtained, even at high molar ratio (8000:1) of o -CNB to Pd.

  9. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan). A study in mice

    DEFF Research Database (Denmark)

    Hougaard, Karin S.; Jackson, Petra; Jensen, Keld A.

    2010-01-01

    to a nanoparticulate UV-filter (UV-titan L181). Methods: Time-mated mice (C57BL/6BomTac) were exposed by inhalation 1h/day to 42 mg/m(3) aerosolized powder (1.7.10(6) n/cm(3); peak-size: 97 nm) on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring...... the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test). Conclusion: Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally...

  10. Synthesis of spherical Ag/ZnO heterostructural composites with excellent photocatalytic activity under visible light and UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hairui, E-mail: liuhairui1@126.com [College of Physics & Electronics Engineering, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 (China); Hu, Yanchun [College of Physics & Electronics Engineering, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 (China); Zhang, Zhuxia [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Liu, Xuguang [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi 030024 (China); Jia, Husheng [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Xu, Bingshe [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi 030024 (China)

    2015-11-15

    Graphical abstract: Ag nanoparticles decorated ZnO microspheres heterostructural composites were fabricated via a two-step chemical method, and present enhanced UV and visible light photocatalytic activity, which ascribed to the formation of Schottky barriers in the regions between Ag-NPs and ZnO-MSs and effective electron transfer from plasmon-excited Ag(0) nanoparticles to ZnO-MSs by strong localization of surface plasmonic resonance. - Highlights: • Ag/ZnO microspheres heterostructural composites were fabricated via a two-step chemical method. • Ag/ZnO composites exhibits enhanced visible light and UV light photocatalytic activity. • The UV and visible-light photocatalytic activity sequences are different for Ag/ZnO composites with the increase of Ag content. • The enhanced UV and visible light photocatalytic activity could be attributed to the formation of the Schottky barriers and surface plasmon resonance. - Abstract: Ag nanoparticles (Ag-NPs) decorated ZnO microspheres (ZnO-MSs) heterostructural composites were fabricated via a two-step chemical method. The ZnO-MSs with the diameter about 700 nm was initially prepared by ultrasonic technology. Subsequently, Ag-NPs with a diameter of 20–50 nm were anchored onto the surface of the as-prepared ZnO-MSs by a microwave polyol process. The morphology, structural and optical properties of the as-synthesized materials were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, and photoluminescence spectroscopy. The results show that the surface plasmon absorption band of Ag/ZnO composites is distinctly broadened and the PL intensity of Ag/ZnO heterostructural composites varies with the increase of Ag loading. The photocatalytic activity of the Ag/ZnO composites were evaluated by the degradation of rhodamine B (Rh

  11. Synthesis of spherical Ag/ZnO heterostructural composites with excellent photocatalytic activity under visible light and UV irradiation

    International Nuclear Information System (INIS)

    Liu, Hairui; Hu, Yanchun; Zhang, Zhuxia; Liu, Xuguang; Jia, Husheng; Xu, Bingshe

    2015-01-01

    Graphical abstract: Ag nanoparticles decorated ZnO microspheres heterostructural composites were fabricated via a two-step chemical method, and present enhanced UV and visible light photocatalytic activity, which ascribed to the formation of Schottky barriers in the regions between Ag-NPs and ZnO-MSs and effective electron transfer from plasmon-excited Ag(0) nanoparticles to ZnO-MSs by strong localization of surface plasmonic resonance. - Highlights: • Ag/ZnO microspheres heterostructural composites were fabricated via a two-step chemical method. • Ag/ZnO composites exhibits enhanced visible light and UV light photocatalytic activity. • The UV and visible-light photocatalytic activity sequences are different for Ag/ZnO composites with the increase of Ag content. • The enhanced UV and visible light photocatalytic activity could be attributed to the formation of the Schottky barriers and surface plasmon resonance. - Abstract: Ag nanoparticles (Ag-NPs) decorated ZnO microspheres (ZnO-MSs) heterostructural composites were fabricated via a two-step chemical method. The ZnO-MSs with the diameter about 700 nm was initially prepared by ultrasonic technology. Subsequently, Ag-NPs with a diameter of 20–50 nm were anchored onto the surface of the as-prepared ZnO-MSs by a microwave polyol process. The morphology, structural and optical properties of the as-synthesized materials were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, and photoluminescence spectroscopy. The results show that the surface plasmon absorption band of Ag/ZnO composites is distinctly broadened and the PL intensity of Ag/ZnO heterostructural composites varies with the increase of Ag loading. The photocatalytic activity of the Ag/ZnO composites were evaluated by the degradation of rhodamine B (Rh

  12. Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial.

    Science.gov (United States)

    Castanedo-Cazares, Juan Pablo; Hernandez-Blanco, Diana; Carlos-Ortega, Blanca; Fuentes-Ahumada, Cornelia; Torres-Álvarez, Bertha

    2014-02-01

    Melasma is an acquired hyperpigmentation on sun-exposed areas. Multiple approaches are used to treat it, but all include broad ultraviolet (UV)-spectrum sunscreens. Visible light (VL) can induce pigmentary changes similar to those caused by UV radiation on darker-skinned patients. To assess the efficacy of sunscreen with broad-spectrum UV protection that contains iron oxide as a VL-absorbing pigment (UV-VL) compared with a regular UV-only broad-spectrum sunscreen for melasma patients exposed to intense solar conditions. Sixty-eight patients with melasma were randomized in two groups to receive either UV-VL sunscreen or UV-only sunscreen, both with sun protection factor ≥ 50, over 8 weeks. All patients received 4% hydroquinone as a depigmenting treatment. At onset and at conclusion of the study, they were assessed by the Melasma Activity and Severity Index (MASI; a subjective scale), colorimetry (L*) and histological analysis of melanin. Sixty-one patients concluded the study. At 8 weeks, the UV-VL group showed 15%, 28% and 4% greater improvements than the UV-only group in MASI scores, colorimetric values and melanin assessments, respectively. UV-VL sunscreen enhances the depigmenting efficacy of hydroquinone compared with UV-only sunscreen in treatment of melasma. These findings suggest a role for VL in melasma pathogenesis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. The effect of ultraviolet-B radiation on gene expression and pigment composition in etiolated and green pea leaf tissue: UV-B-induced changes are gene-specific and dependent upon the developmental stage

    International Nuclear Information System (INIS)

    Jordan, B.R.; James, P.E.; Strid, A.; Anthony, R.G.

    1994-01-01

    The effect of ultraviolet-B radiation (UV-B: 280–320nm) on gene expression and pigment composition has been investigated in pea tissue at different stages of development. Pea (Pisum sativum L., cv. Feltham First) seedlings were grown for 17d and then exposed to supplementary UV-B radiation. Chlorophyll a per unit fresh weight decreased by more than 20% compared with control levels after exposure to UV-B radiation for 7d. In contrast, chlorophyll b content remained the same or increased slightly. Leaf protein biosynthesis, as determined by 35 S-methionine incorporation, was rapidly inhibited by UV-B radiation, although the steady-state levels of proteins were either unchanged or only slightly altered. RNA transcripts for the chlorophyll a/b binding protein (cab) were also rapidly reduced to low or even undetectable levels in the expanded third leaf or younger leaf bud tissue after exposure to UV-B radiation. In contrast, cab RNA transcripts were either low or undetectable in etiolated pea tissue, but increased substantially in light and during exposure to UV-B radiation. The cab RNA transcripts were still present at control levels in pea plants after 7d of greening under supplementary UV-B radiation or UV-B alone. The protein composition changed significantly over the 7d of greening, but no differences could be detected between the light treatments. The increase in chlorophyll content was slightly greater during de-etiolation under supplementary UV-B radiation than under control irradiance. Under UV-B radiation alone, chlorophyll was synthesized at a greatly reduced rate. Changes in protective pigments were also determined. Anthocyanins did not change in either etiolated or green tissue exposed to UV-B radiation. However, other flavonoids increased substantially in either tissue during exposure to light and UV-B radiation. The RNA levels for chalcone synthase were measured in green and etiolated tissue exposed to UV-B radiation. The chs RNA transcripts were

  14. Uveka: a UV exposure monitoring system using autonomous instruments network for Reunion Island citizens

    Science.gov (United States)

    Sébastien, Nicolas; Cros, Sylvain; Lallemand, Caroline; Kurzrock, Frederik; Schmutz, Nicolas

    2016-04-01

    Reunion Island is a French oversea territory located in the Indian Ocean. This tropical Island has about 840,000 inhabitants and is visited every year by more than 400,000 tourists. On average, 340 sunny days occurs on this island in a whole year. Beyond these advantageous conditions, exposure of the population to ultraviolet radiation constitutes a public health issue. The number of hospitalisations for skin cancer increased by 50% between 2005 and 2010. Health insurance reimbursements due to ophthalmic anomalies caused by the sun is about two million Euros. Among the prevention measures recommended by public health policies, access to information on UV radiation is one of the basic needs. Reuniwatt, supported by the Regional Council of La Reunion, is currently developing the project Uveka. Uveka is a solution permitting to provide in real-time and in short-term forecast (several hours), the UV radiation maps of the Reunion Island. Accessible via web interface and smartphone application, Uveka informs the citizens about the UV exposure rate and its risk according to its individual characteristics (skin phototype, past exposure to sun etc.). The present work describes this initiative through the presentation of the UV radiation monitoring system and the data processing chain toward the end-users. The UV radiation monitoring system of Uveka is a network of low cost UV sensors. Each instrument is equipped with a solar panel and a battery. Moreover, the sensor is able to communicate using the 3G telecommunication network. Then, the instrument can be installed without AC power or access to a wired communication network. This feature eliminates a site selection constraint. Indeed, with more than 200 microclimates and a strong cloud cover spatial variability, building a representative measurement site network in this island with a limited number of instruments is a real challenge. In addition to these UV radiation measurements, the mapping of the surface solar radiation

  15. Effect of vitamin E on cytotoxicity, DNA single strand breaks, chromosomal aberrations, and mutation in Chinese hamster V-79 cells exposed to ultraviolet-B light

    International Nuclear Information System (INIS)

    Sugiyama, M.; Tsuzuki, K.; Matsumoto, K.; Ogura, R.

    1992-01-01

    The effect of pretreatment with vitamin E on cytotoxicity, DNA single strand breaks, and chromosomal aberrations as well as on mutation induced by ultraviolet-B light (UV-B) was investigated in Chinese hamster V-79 cells. Cellular pretreatment with non-toxic levels of 25 μM α-tocopherol succinate (vitamin E) for 24h prior to exposure resulted in a 10-fold increase in cellular levels of α-tocopherol. Using a colony-forming assay, this pretreatment decreased the cytotoxicity of UV-B light. However, alkaline elution assays demonstrated that pretreatment with vitamin E did not affect the number of DNA single strand breaks caused by UV-B light. UV-B exposure produced a dose-dependent induction of chromosomal aberrations and mutations at the HGPRT locus, and neither of these actions of UV-B was influenced by pretreatment with the vitamin. These results suggest that vitamin E protects cells from UV-B-induced cytotoxicity, possibly through its ability to scavenge free radicals. The genotoxicity induced by UV-B light may not correlate directly with the cytotoxic action of this wavelength region in sunlight. (author)

  16. UV light selectively coinduces supply pathways from primary metabolism and flavonoid secondary product formation in parsley

    Science.gov (United States)

    Logemann, Elke; Tavernaro, Annette; Schulz, Wolfgang; Somssich, Imre E.; Hahlbrock, Klaus

    2000-01-01

    The UV light-induced synthesis of UV-protective flavonoids diverts substantial amounts of substrates from primary metabolism into secondary product formation and thus causes major perturbations of the cellular homeostasis. Results from this study show that the mRNAs encoding representative enzymes from various supply pathways are coinduced in UV-irradiated parsley cells (Petroselinum crispum) with two mRNAs of flavonoid glycoside biosynthesis, encoding phenylalanine ammonia-lyase and chalcone synthase. Strong induction was observed for mRNAs encoding glucose 6-phosphate dehydrogenase (carbohydrate metabolism, providing substrates for the shikimate pathway), 3-deoxyarabinoheptulosonate 7-phosphate synthase (shikimate pathway, yielding phenylalanine), and acyl-CoA oxidase (fatty acid degradation, yielding acetyl-CoA), and moderate induction for an mRNA encoding S-adenosyl-homocysteine hydrolase (activated methyl cycle, yielding S-adenosyl-methionine for B-ring methylation). Ten arbitrarily selected mRNAs representing various unrelated metabolic activities remained unaffected. Comparative analysis of acyl-CoA oxidase and chalcone synthase with respect to mRNA expression modes and gene promoter structure and function revealed close similarities. These results indicate a fine-tuned regulatory network integrating those functionally related pathways of primary and secondary metabolism that are specifically required for protective adaptation to UV irradiation. Although the response of parsley cells to UV light is considerably broader than previously assumed, it contrasts greatly with the extensive metabolic reprogramming observed previously in elicitor-treated or fungus-infected cells. PMID:10677554

  17. Skin hardening effect in patients with polymorphic light eruption: comparison of UVB hardening in hospital with a novel home UV-hardening device.

    Science.gov (United States)

    Franken, S M; Genders, R E; de Gruijl, F R; Rustemeyer, T; Pavel, S

    2013-01-01

    An effective prophylactic treatment of patients with polymorphic light eruption (PLE) consists of repeated low, gradually increasing exposures to UVB radiation. This so-called UV(B) hardening induces better tolerance of the skin to sunlight. SunshowerMedical company (Amsterdam) has developed an UV (B) source that can be used during taking shower. The low UV fluence of this apparatus makes it an interesting device for UV hardening. In a group of PLE patients, we compared the effectiveness of the irradiation with SunshowerMedical at home with that of the UVB treatment in the hospital. The PLE patients were randomized for one of the treatments. The hospital treatment consisted of irradiations with broad-band UVB (Waldmann 85/UV21 lamps) twice a week during 6 weeks. The home UV-device was used each day with the maximal irradiation time of 6 min. The outcome assessment was based on the information obtained from patients' dermatological quality of life (DLQI) questionnaires, the ability of both phototherapies to reduce the provocation reaction and from the patients' evaluation of the long-term benefits of their phototherapies. Sixteen patients completed treatment with SunshowerMedical and thirteen completed treatment in hospital. Both types of phototherapy were effective. There was a highly significant improvement in DLQI with either treatment. In most cases, the hardening reduced or even completely suppressed clinical UV provocation of PLE. The patients using SunshowerMedical at home were, however, much more content with the treatment procedure than the patients visiting the dermatological units. Both treatments were equally effective in the induction of skin tolerance to sunlight in PLE patients. However, the home treatment was much better accepted than the treatment in the hospital. © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.

  18. UV-activated persulfate oxidation and regeneration of NOM-Saturated granular activated carbon.

    Science.gov (United States)

    An, Dong; Westerhoff, Paul; Zheng, Mengxin; Wu, Mengyuan; Yang, Yu; Chiu, Chao-An

    2015-04-15

    A new method of ultraviolet light (UV) activated persulfate (PS) oxidation was investigated to regenerate granular activated carbon (GAC) in drinking water applications. The improvements in iodine and methylene blue numbers measured in the GAC after ultraviolet- (UV) activated persulfate suggested that the GAC preloaded with natural organic matter (NOM) was chemically regenerated. An experimental matrix for UV-activated persulfate regeneration included a range of persulfate doses and different UV wavelengths. Over 87% of the initial iodine number for GAC was restored under the optimum conditions, perfulfate dosage 60 g/L and UV exposure 1.75 × 10(4) mJ/cm(2). The persulfate dosages had little effect on the recovery of the methylene blue number, which was approximately 65%. Persulfate activation at 185 nm was superior to activation at 254 nm. UV activation of persulfate in the presence of GAC produced acid, lowering the solution pH. Higher persulfate concentrations and UV exposure resulted in greater GAC regeneration. Typical organic and inorganic byproducts (e.g., benzene compounds and sulfate ions) were measured as a component of treated water quality safety. This study provides a proof-of-concept that can be used to optimize pilot-scale and full-scale UV-activated persulfate for regeneration of NOM-saturated GAC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kääriäinen, Tommi, E-mail: tommi.kaariainen@colorado.edu [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Johansson, Petri, E-mail: petri.johansson@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Kotkamo, Sami, E-mail: sami.kotkamo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Seppänen, Tarja, E-mail: tarja.seppanen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Cameron, David C., E-mail: david.cameron@miktech.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland)

    2014-11-03

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved.

  20. The solar UV exposure time required for vitamin D3 synthesis in the human body estimated by numerical simulation and observation in Japan

    Science.gov (United States)

    Nakajima, Hideaki; Miyauchi, Masaatsu; Hirai, Chizuko

    2013-04-01

    After the discovery of Antarctic ozone hole, the negative effect of exposure of human body to harmful solar ultraviolet (UV) radiation is widely known. However, there is positive effect of exposure to UV radiation, i.e., vitamin D synthesis. Although the importance of solar UV radiation for vitamin D3 synthesis in the human body is well known, the solar exposure time required to prevent vitamin D deficiency has not been well determined. This study attempted to identify the time of solar exposure required for vitamin D3 synthesis in the body by season, time of day, and geographic location (Sapporo, Tsukuba, and Naha, in Japan) using both numerical simulations and observations. According to the numerical simulation for Tsukuba at noon in July under a cloudless sky, 2.3 min of solar exposure are required to produce 5.5 μg vitamin D3 per 600 cm2 skin. This quantity of vitamin D represents the recommended intake for an adult by the Ministry of Health, Labour and Welfare, and the 2010 Japanese Dietary Reference Intakes (DRIs). In contrast, it took 49.5 min to produce the same amount of vitamin D3 at Sapporo in the northern part of Japan in December, at noon under a cloudless sky. The necessary exposure time varied considerably with the time of the day. For Tsukuba at noon in December, 14.5 min were required, but at 09:00 68.7 min were required and at 15:00 175.8 min were required for the same meteorological conditions. Naha receives high levels of UV radiation allowing vitamin D3 synthesis almost throughout the year. According to our results, we are further developing an index to quantify the necessary time of UV radiation exposure to produce required amount of vitamin D3 from a UV radiation data.

  1. Transmission of UV-irradiance into nectarine fruit

    International Nuclear Information System (INIS)

    Blanke, M.M.

    1996-01-01

    With the global depletion of the ozone layer, leaves and fruits are increasingly exposed to UV-irradiance on the tree. Some fruits are additionally exposed postharvest to artificial germicidal W-irradiance, leading to a cumulative effect. This paper examines the transmission of UV-light (200-400 nm) by the peel of ripe nectarine fruit using UV/VIS spectrophotometry to aid understanding of UV-effects and assess the sensitivity of the peel to UV wavelengths. Yellow peel of nectarine fruit transmitted less than 0.1 % in the UV-C range of 220 to 280 nm. With longer wavelenghts, UV-light transmission increased slowly from 0.4 % at 284 nm to 1.6 % at 320 nm and, in the UV-A region, progressively from 1.9 % at 330 nm to a maximum of 13 % of incident irradiance at 400 nm. Red peel of nectarine fruit transmitted less than 0.1 % of UV-C and UV-B light, but up to 0.9 % of incident UV-A light at 400 nm. Conversely, UV-absorption of nectarine peel decreased with longer wavelengths. Hence, fruit parenchyma is more affected by UV-irradiance at wavelengths above ca. 280 nm and underneath yellow than underneath red peel

  2. A novel and simple fabrication method of embedded SU-8 micro channels by direct UV lithography

    International Nuclear Information System (INIS)

    Fu, C; Hung, C; Huang, H

    2006-01-01

    In this paper, we presents a novel and simple method to fabricate embedded micro channels. The method based on different light absorption properties of the SU-8 thick photoresist under different incident UV wavelengths. The channel structures are defined by the ordinary I-line, while the cover layer is patterned by the deep UV. Because the deep UV is obtained directly on the same aligner with a set of filter mirrors, the embedded channel can be easily produced without other rare facilities. Besides, the relationship between the thickness of the top layer and the exposure dose of the deep UV has been measured by an ingeniously designed experiment. The specific thickness of the top layer of the embedded micro channel can then be secured by the specific deep-UV exposure dose. Further more, many meaningful mechanical structures have been realized by this method, the material property of the top layer are also measured

  3. Recovery from damage induced by acridine plus near-ultraviolet light in Escherichia coli

    International Nuclear Information System (INIS)

    Wagner, S.; Feldman, A.; Snipes, W.

    1982-01-01

    Escherichia coli cells treated with sublethal doses of acridine plus near-UV light exhibit an effective split-dose recovery response that requires an incubation period of about 30-45 min. Studies of the metabolic requirements for split-dose recovery revealed the following: (a) DNA synthesis is not required for split-dose recovery: (b) inhibition of electron transport or protein synthesis reduces the efficiency of split-dose recovery by about one-half: (c) inhibition of phospholipid synthesis or cell wall synthesis completely eliminates the split-dose recovery response. These results suggest an involvement of membrane repair mechanisms in response to damage by acridine plus near-UV light. Additional evidence for such a process was provided by more direct assays for membrane recovery. It was found that cells treated with sublethal doses of acridine plus near-UV light are sensitive to low concentrations of detergents, and lose that sensitivity upon incubation. Likewise, treated cells are susceptible to lethal osmotic shock, but can recover from this susceptibility if incubated after treatment but prior to exposure to low osmotic conditions. Based on accumulating evidence it is proposed that E. coli cells are capable of repairing membrane damage resulting from exposure to acridine plus near-UV light. (author)

  4. Transcriptional and cellular effects of benzotriazole UV stabilizers UV-234 and UV-328 in the freshwater invertebrates Chlamydomonas reinhardtii and Daphnia magna.

    Science.gov (United States)

    Giraudo, Maeva; Cottin, Guillaume; Esperanza, Marta; Gagnon, Pierre; Silva, Amila O De; Houde, Magali

    2017-12-01

    Benzotriazole ultra violet stabilizers (BZT-UVs) are compounds used in many applications and products to prevent photochemical degradation. Despite their widespread presence in aquatic ecosystems and persistence in the environment, there are very limited data on their effects and toxicity, and their modes of action remain largely unknown. The objectives of the present study were to evaluate the chronic effects of 2 BZT-UVs, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV-234) and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), on the freshwater green algae Chlamydomonas reinhardtii and the freshwater crustacean Daphnia magna. Organisms were exposed to 0.01 and 10 μg/L of UV-234, UV-328, as well as a mixture of the 2 compounds. Life-history endpoints (viability, reproduction, and growth) and oxidative stress-related biomarkers (gene transcription, reactive oxygen species [ROS] production, and lipid peroxidation) were measured. Daphnia magna growth, reproduction, and gene transcription were not impacted by 21-d individual or mixed exposure. After 96-h of exposure, no differences were observed on the cellular viability of C. reinhardtii for either of the 2 BZT-UVs. In the algae, results showed increased ROS production in response to UV-328 and lipid peroxidation following exposure to UV-234. Synergistic effects of the 2 BZT-UVs were evident at the transcriptional level with 2 to 6 times up-regulation of glutathione peroxidase (gp x ) in response to the mixture for all treatment conditions. The transcription of superoxide dismutase (sod), catalase (cat), and ascorbic peroxidase (apx) was also regulated by UV-234 and UV-328 in the green algae, most likely as a result of ROS production and lipid peroxidation. Results from the present study suggest potential impacts of UV-234 and UV-328 exposure on the antioxidant defense system in C. reinhardtii. Environ Toxicol Chem 2017;36:3333-3342. © 2017 Crown in the Right of Canada. Published by

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

    Science.gov (United States)

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

    2011-08-01

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

  6. Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO2

    International Nuclear Information System (INIS)

    Triantis, T.M.; Fotiou, T.; Kaloudis, T.; Kontos, A.G.; Falaras, P.; Dionysiou, D.D.; Pelaez, M.; Hiskia, A.

    2012-01-01

    Highlights: ► N-TiO 2 exhibited effective degradation of MC-LR under UV-A, solar and visible light. ► Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. ► The organic nitrogen is mainly released as ammonium and nitrate ions. - Abstract: In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO 2 (N-TiO 2 ) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO 2 , Kronos and reference TiO 2 nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO 2 followed by N-TiO 2 with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO 2 nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO 2 for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO 2 displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO 2 − , NO 3 − and NH 4 + ) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

  7. Characterisation of the p53-mediated cellular responses evoked in primary mouse cells following exposure to ultraviolet radiation.

    Directory of Open Access Journals (Sweden)

    Gillian D McFeat

    Full Text Available Exposure to ultraviolet (UV light can cause significant damage to mammalian cells and, although the spectrum of damage produced varies with the wavelength of UV, all parts of the UV spectrum are recognised as being detrimental to human health. Characterising the cellular response to different wavelengths of UV therefore remains an important aim so that risks and their moderation can be evaluated, in particular in relation to the initiation of skin cancer. The p53 tumour suppressor protein is central to the cellular response that protects the genome from damage by external agents such as UV, thus reducing the risk of tumorigenesis. In response to a variety of DNA damaging agents including UV light, wild-type p53 plays a role in mediating cell-cycle arrest, facilitating apoptosis and stimulating repair processes, all of which prevent the propagation of potentially mutagenic defects. In this study we examined the induction of p53 protein and its influence on the survival of primary mouse fibroblasts exposed to different wavelengths of UV light. UVC was found to elevate p53 protein and its sequence specific DNA binding capacity. Unexpectedly, UVA treatment failed to induce p53 protein accumulation or sequence specific DNA binding. Despite this, UVA exposure of wild-type cells induced a p53 dependent G1 cell cycle arrest followed by a wave of p53 dependent apoptosis, peaking 12 hours post-insult. Thus, it is demonstrated that the elements of the p53 cellular response evoked by exposure to UV radiation are wavelength dependent. Furthermore, the interrelationship between various endpoints is complex and not easily predictable. This has important implications not only for understanding the mode of action of p53 but also for the use of molecular endpoints in quantifying exposure to different wavelengths of UV in the context of human health protection.

  8. Influence of post-deposition treatment by UV light and oxygen (ozone) on 350 nm damage thresholds of SiO2 films deposited from sols

    International Nuclear Information System (INIS)

    Thomas, I.; Wilder, J.; Lee, A.; George, D.

    1988-01-01

    Certain multilayer porous silica AR coatings on fused silica substrates prepared by the sol-gel process have been found to have a much lower laser damage threshold than single layer coatings prepared by the same method. Treatment with UV light in the presence of oxygen (which gives ozone) at low temperature was found to restore damage thresholds to the levels found in single layers. Damage thresholds were measured at 350 nm with a 25 ns pulse for 1000 shots at 25 Hz. The effect of exposure time and other factors such as replacement of oxygen with nitrogen and vacuum are described

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

    Directory of Open Access Journals (Sweden)

    Yanzhi Wang

    2013-01-01

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

  10. UV light-induced cyclobutane pyrimidine dimers are mutagenic in mammalian cells

    International Nuclear Information System (INIS)

    Protic-Sabljic, M.; Tuteja, N.; Munson, P.J.; Hauser, J.; Kraemer, K.H.; Dixon, K.

    1986-01-01

    We used a simian virus 40-based shuttle vector plasmid, pZ189, to determine the role of pyrimidine cyclobutane dimers in UV light-induced mutagenesis in monkey cells. The vector DNA was UV irradiated and then introduced into monkey cells by transfection. After replication, vector DNA was recovered from the cells and tested for mutations in its supF suppressor tRNA marker gene by transformation of Escherichia coli carrying a nonsense mutation in the beta-galactosidase gene. When the irradiated vector was treated with E. coli photolyase prior to transfection, pyrimidine cyclobutane dimers were removed selectively. Removal of approximately 90% of the pyrimidine cyclobutane dimers increased the biological activity of the vector by 75% and reduced its mutation frequency by 80%. Sequence analysis of 72 mutants recovered indicated that there were significantly fewer tandem double-base changes and G X C----A X T transitions (particularly at CC sites) after photoreactivation of the DNA. UV-induced photoproducts remained (although at greatly reduced levels) at all pyr-pyr sites after photoreactivation, but there was a relative increase in photoproducts at CC and TC sites and a relative decrease at TT and CT sites, presumably due to a persistence of (6-4) photoproducts at some CC and TC sites. These observations are consistent with the fact that mutations were found after photoreactivation at many sites at which only cyclobutane dimers would be expected to occur. From these results we conclude that UV-induced pyrimidine cyclobutane dimers are mutagenic in DNA replicated in monkey cells

  11. Elodea nuttallii exposure to mercury exposure under enhanced ultraviolet radiation: Effects on bioaccumulation, transcriptome, pigment content and oxidative stress.

    Science.gov (United States)

    Regier, Nicole; Beauvais-Flück, Rebecca; Slaveykova, Vera I; Cosio, Claudia

    2016-11-01

    The hypothesis that increased UV radiation result in co-tolerance to Hg toxicity in aquatic plants was studied at the physiological and transcriptomic level in Elodea nuttallii. At the transcriptomic level, combined exposure to UV+Hg enhanced the stress response in comparison with single treatments, affecting the expression level of transcripts involved in energy metabolism, lipid metabolism, nutrition, and redox homeostasis. Single and combined UV and Hg treatments dysregulated different genes but with similar functions, suggesting a fine regulation of the plant to stresses triggered by Hg, UV and their combination but lack of co-tolerance. At the physiological level, UV+Hg treatment reduced chlorophyll content and depleted antioxidative compounds such as anthocyanin and GSH/GSSG in E. nuttallii. Nonetheless, combined exposure to UV+Hg resulted in about 30% reduction of Hg accumulation into shoots vs exposure to Hg alone, which was congruent with the level of expression of several transporter genes, as well as the UV effect on Hg bioavailability in water. The findings of the present work underlined the importance of performing experimentation under environmentally realistic conditions and to consider the interplay between contaminants and environmental variables such as light that might have confounding effects to better understand and anticipate the effects of multiple stressors in aquatic environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Synthesis of polyaniline nanotubes through UV light catalytic method

    Directory of Open Access Journals (Sweden)

    Chuanyu Sun

    2015-03-01

    Full Text Available In this study, nitrocellulose (NC fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO32 as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4SiW12O40, SiW12 using UV light catalytic method. Infrared spectroscopy (IR, X-ray powder diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM technologies were applied to characterize the prepared samples of polyaniline nanotubes. The results show that the external diameter of the tube is about 200 nm, and the internal diameter about 170 nm. We also give a reasonable speculation and explanation about the formation mechanism of the nanotubes.

  13. Effect of evening exposure to bright or dim light after daytime bright light on absorption of dietary carbohydrates the following morning.

    Science.gov (United States)

    Hirota, Naoko; Sone, Yoshiaki; Tokura, Hiromi

    2010-01-01

    We had previously reported on the effect of exposure to light on the human digestive system: daytime bright light exposure has a positive effect, whereas, evening bright light exposure has a negative effect on the efficiency of dietary carbohydrate absorption from the evening meal. These results prompted us to examine whether the light intensity to which subjects are exposed in the evening affects the efficiency of dietary carbohydrate absorption the following morning. In this study, subjects were exposed to either 50 lux (dim light conditions) or 2,000 lux (bright light conditions) in the evening for 9 h (from 15:00 to 24:00) after staying under bright light in the daytime (under 2,000 lux from 07:00 to 15:00). We measured unabsorbed dietary carbohydrates using the breath-hydrogen test the morning after exposure to either bright light or dim light the previous evening. Results showed that there was no significant difference between the two conditions in the amount of breath hydrogen. This indicates that evening exposure to bright or dim light after bright light exposure in the daytime has no varying effect on digestion or absorption of dietary carbohydrates in the following morning's breakfast.

  14. Plant responses to UV-B irradiation are modified by UV-A irradiation

    International Nuclear Information System (INIS)

    Middleton, E.M.; Teramura, A.H.

    1993-01-01

    The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

  15. Effect of UV-C irradiation on growth, sporulation and pathogenicity of cochliobolus sativus isolates

    International Nuclear Information System (INIS)

    Jawhar, M.; Arabi, M.I.E.

    1999-12-01

    More than 30 isolates of Cochliobolus sativus, the causal agent of common root rot disease; were collected from different regions of Syria. Seven of them were exposed to UV-C light for 40 or 60 h . at a dose rate of 2.52x10 -3 W/cm 2 . A significant increases in the mycelium growth and sporulation were detected (p<0.001). Within the studied range of UV wave length, these two parameters were increased upon increasing the period of exposure to UV-C light. The pathogenicity of four isolates was evaluated after 60 h. of UV irradiation. The response to UV irradiation varied among these isolates, and resulted in an increase in their virulence level (as assessed by evaluating disease severity on sub-crown internodes). Five barley genotypes possessing different levels of resistance to C. sativus were studied. Arabi Abiad was the most susceptible cultivar whereas, Taka 76 line was moderately susceptible. It is concluded that it is possible to implement the positive effect of low doses of UV-C in stimulating the sporulation of fungi, which are difficult to sporulate on artificial media. (author)

  16. The effect of UV-C exposure on larval survival of the dreissenid quagga mussel

    Science.gov (United States)

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri K.; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  17. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

    Science.gov (United States)

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  18. Cutaneous solar ultraviolet exposure and clinical aspects of photodamage

    Directory of Open Access Journals (Sweden)

    Claire Battie

    2012-01-01

    Full Text Available Solar ultraviolet (UV radiation reaching the earth is a combination of UVB (290-320 nm and UVA (320-400 nm wavelengths. Since UVA is less energetic than UVB, UVB has long been thought to be the factor responsible for the damaging effects of solar radiation. But with modern tools such as in vitro models, it has been proven that UVA plays a major role. The objective of this review is to show how skin may be exposed to UV light and to highlight the clinical aspects of UV-induced skin damages with the respective contribution of UVB or UVA. Even if UVA is less energetic than UVB, it is more abundant and penetrates deeper into the skin, reaching as far as the dermis. Various factors also influence skin exposure to UV light: the latitude, season, and time of the day. Acute as well as chronic sun exposure induces short- and long-term clinical damages. Erythema and pigmentation are immediate responses of normal human skin exposed to UV radiation. The long-term effects are photoaging and photocarcinogenesis. In particular, UVA appears to play a major role in the deterioration of dermal structure leading to the photoaged appearance of the skin.

  19. Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines.

    Science.gov (United States)

    Zakaria, Fiona; Harelimana, Bertin; Ćurko, Josip; van de Vossenberg, Jack; Garcia, Hector A; Hooijmans, Christine Maria; Brdjanovic, Damir

    2016-01-01

    Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.

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

    International Nuclear Information System (INIS)

    Ullrich, S.E.

    1996-01-01

    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)

  1. Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson's disease epidemiology.

    Science.gov (United States)

    Romeo, Stefania; Viaggi, Cristina; Di Camillo, Daniela; Willis, Allison W; Lozzi, Luca; Rocchi, Cristina; Capannolo, Marta; Aloisi, Gabriella; Vaglini, Francesca; Maccarone, Rita; Caleo, Matteo; Missale, Cristina; Racette, Brad A; Corsini, Giovanni U; Maggio, Roberto

    2013-01-01

    This study explores the effect of continuous exposure to bright light on neuromelanin formation and dopamine neuron survival in the substantia nigra. Twenty-one days after birth, Sprague-Dawley albino rats were divided into groups and raised under different conditions of light exposure. At the end of the irradiation period, rats were sacrificed and assayed for neuromelanin formation and number of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra. The rats exposed to bright light for 20 days or 90 days showed a relatively greater number of neuromelanin-positive neurons. Surprisingly, TH-positive neurons decreased progressively in the substantia nigra reaching a significant 29% reduction after 90 days of continuous bright light exposure. This decrease was paralleled by a diminution of dopamine and its metabolite in the striatum. Remarkably, in preliminary analysis that accounted for population density, the age and race adjusted Parkinson's disease prevalence significantly correlated with average satellite-observed sky light pollution.

  2. UV light induces premature senescence in Akt1-null mouse embryonic fibroblasts by increasing intracellular levels of ROS

    International Nuclear Information System (INIS)

    Jee, Hye Jin; Kim, Hyun-Ju; Kim, Ae Jeong; Bae, Yoe-Sik; Bae, Sun Sik; Yun, Jeanho

    2009-01-01

    Akt/PKB plays a pivotal role in cell survival and proliferation. Previously, we reported that UV-irradiation induces extensive cell death in Akt2 -/- mouse embryonic fibroblasts (MEFs) while Akt1 -/- MEFs show cell cycle arrest. Here, we find that Akt1 -/- MEFs exhibit phenotypic changes characteristics of senescence upon UV-irradiation. An enlarged and flattened morphology, a reduced cell proliferation and an increased senescence-associated β-galactosidase (SA β-gal) staining indicate that Akt1 -/- MEFs undergo premature senescence after UV-irradiation. Restoring Akt1 expression in Akt1 -/- MEFs suppressed SA β-gal activity, indicating that UV-induced senescence is due to the absence of Akt1 function. Notably, levels of ROS were rapidly increased upon UV-irradiation and the ROS scavenger NAC inhibits UV-induced senescence of Akt1 -/- MEFs, suggesting that UV light induces premature senescence in Akt1 -/- MEFs by modulating intracellular levels of ROS. In conjunction with our previous work, this indicates that different isoforms of Akt have distinct function in response to UV-irradiation.

  3. Regulation of Expression of the prb-1b / ACC Deaminase gene by UV-B in Transgenic tomatoes

    International Nuclear Information System (INIS)

    Tamot, B.K.; Pauls, K.P.; Glick, R.

    2003-01-01

    Transgenic tomato plants with 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase gene from Enterobacter cloacae UWA4 under the control of a pathogenesis-related promoter (prb-1b) from tobacco were challenged by abiotic stresses to determine the expression patterns of the transgene. No ACC deaminase RNA or protein was detected bu RT-PCR and in western blots prepared from leaf proteins of transgenic plants after wounding or treatment with alpha-amino butyric acid, xylanase, ethephon, salicylic acid, jasmonic acid , ethylene, or ethylene plus jasmonic acid. However, expression of the ACC deaminase transgene was observed in leaves and roots of transformed tomato lines exposed to UV light. The UV response required a minimum of 48 h of exposure and was specific to UV-B light

  4. Investigation of the use of FXG gel dosimeter for UV radiation detection

    International Nuclear Information System (INIS)

    Bero, M.; Abu Kassem, I.

    2009-02-01

    The radio-chromic chemical radiation dosimeter is well known type of detectors that have been used in the measurement application of radiation dose resulting for ionizing radiation such as γ and X-rays. The detector materials consist of mainly water with added gelatin powder that gives the detector its solid shape. Other chemicals sensitive to radiation are also added to form the Ferrous-sulfate Xylenol-orange Gelatin gel detector (FXG). Ionizing radiation effects appears as an increase in the optical absorbance within a defined range of wavelengths located in the visible region of the light spectrum. These visible changes in the materials optical characteristic as a result of radiation exposure is proportional to the radiation absorbed dose at certain wave lengths. Ultraviolet radiation was found to produce similar effects in the FXG detector materials; hence we suggested studying the UV effects in details. It is known that UV radiation carry relatively high quantum energies big enough to enhance important chemical and biological reactions in some exposed medium. This study examines the most important properties required for the FXG detector to be used as a UV monitoring system that is capable of measuring the absorbed UV radiation dose. The study also works on finding chemical detector structure that is easy to be used for simulating the UV interactions with human body. It has been shown that the optical absorbance of standard size FXG samples increases linearly with the exposure time to UV radiation produced by a sun simulator source, when the beam is filtered to produces exposure similar to that found in nature. However, the UV effects are also influenced by the applied UV radiation spectrum used for irradiation as well as the thicknesses of the FXG materials.(authors)

  5. UV irradiation to mouse skin decreases hippocampal neurogenesis and synaptic protein expression via HPA axis activation.

    Science.gov (United States)

    Han, Mira; Ban, Jae-Jun; Bae, Jung-Soo; Shin, Chang-Yup; Lee, Dong Hun; Chung, Jin Ho

    2017-11-14

    The skin senses external environment, including ultraviolet light (UV). Hippocampus is a brain region that is responsible for memory and emotion. However, changes in hippocampus by UV irradiation to the skin have not been studied. In this study, after 2 weeks of UV irradiation to the mouse skin, we examined molecular changes related to cognitive functions in the hippocampus and activation of the hypothalamic-pituitary-adrenal (HPA) axis. UV exposure to the skin decreased doublecortin-positive immature neurons and synaptic proteins, including N-methyl-D-aspartate receptor 2 A and postsynaptic density protein-95, in the hippocampus. Moreover, we observed that UV irradiation to the skin down-regulated brain-derived neurotrophic factor expression and ERK signaling in the hippocampus, which are known to modulate neurogenesis and synaptic plasticity. The cutaneous and central HPA axes were activated by UV, which resulted in significant increases in serum levels of corticosterone. Subsequently, UV irradiation to the skin activated the glucocorticoid-signaling pathway in the hippocampal dentate gyrus. Interestingly, after 6 weeks of UV irradiation, mice showed depression-like behavior in the tail suspension test. Taken together, our data suggest that repeated UV exposure through the skin may negatively affect hippocampal neurogenesis and synaptic plasticity along with HPA axis activation.

  6. Super Water-Repellent Fractal Surfaces of a Photochromic Diarylethene Induced by UV Light

    Science.gov (United States)

    Izumi, Norikazu; Minami, Takayuki; Mayama, Hiroyuki; Takata, Atsushi; Nakamura, Shinichiro; Yokojima, Satoshi; Tsujii, Kaoru; Uchida, Kingo

    2008-09-01

    Photochromic diarylethene forms super water-repellent surfaces upon irradiation with UV light. Microfibril-like crystals grow on the solid diarylethene surface after UV irradiation, and the contact angle of water on the surface becomes larger with increasing surface roughness with time. The fractal analysis was made by the box-counting method for the rough surfaces. There are three regions in the roughness size having the fractal dimension of ca. 2.4 (size of roughness smaller than 5 µm), of ca. 2.2 (size of roughness between 5-40 µm), and of ca. 2.0 (size of roughness larger than 40 µm). The fractal dimension of ca. 2.4 was due to the fibril-like structures generated gradually by UV irradiation on diarylethene surfaces accompanied with an increase in the contact angle. The surface structure with larger fractal dimension mainly contributes to realizing the super water-repellency of the diarylethene surfaces. This mechanism of spontaneous formation of fractal surfaces is similar to that for triglyceride and alkylketene dimer waxes.

  7. Improved photoluminescence efficiency in UV nanopillar light emitting diode structures by recovery of dry etching damage.

    Science.gov (United States)

    Jeon, Dae-Woo; Jang, Lee-Woon; Jeon, Ju-Won; Park, Jae-Woo; Song, Young Ho; Jeon, Seong-Ran; Ju, Jin-Woo; Baek, Jong Hyeob; Lee, In-Hwan

    2013-05-01

    In this study, we have fabricated 375-nm-wavelength InGaN/AlInGaN nanopillar light emitting diodes (LED) structures on c-plane sapphire. A uniform and highly vertical nanopillar structure was fabricated using self-organized Ni/SiO2 nano-size mask by dry etching method. To minimize the dry etching damage, the samples were subjected to high temperature annealing with subsequent chemical passivation in KOH solution. Prior to annealing and passivation the UV nanopillar LEDs showed the photoluminescence (PL) efficiency about 2.5 times higher than conventional UV LED structures which is attributed to better light extraction efficiency and possibly some improvement of internal quantum efficiency due to partially relieved strain. Annealing alone further increased the PL efficiency by about 4.5 times compared to the conventional UV LEDs, while KOH passivation led to the overall PL efficiency improvement by more than 7 times. Combined results of Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) suggest that annealing decreases the number of lattice defects and relieves the strain in the surface region of the nanopillars whereas KOH treatment removes the surface oxide from nanopillar surface.

  8. UV light B-mediated inhibition of skin catalase activity promotes Gr-1+ CD11b+ myeloid cell expansion.

    Science.gov (United States)

    Sullivan, Nicholas J; Tober, Kathleen L; Burns, Erin M; Schick, Jonathan S; Riggenbach, Judith A; Mace, Thomas A; Bill, Matthew A; Young, Gregory S; Oberyszyn, Tatiana M; Lesinski, Gregory B

    2012-03-01

    Skin cancer incidence and mortality are higher in men compared with women, but the causes of this sex discrepancy remain largely unknown. UV light exposure induces cutaneous inflammation and neutralizes cutaneous antioxidants. Gr-1(+)CD11b(+) myeloid cells are heterogeneous bone marrow-derived cells that promote inflammation-associated carcinogenesis. Reduced activity of catalase, an antioxidant present in the skin, has been associated with skin carcinogenesis. We used the outbred, immune-competent Skh-1 hairless mouse model of UVB-induced inflammation and non-melanoma skin cancer to further define sex discrepancies in UVB-induced inflammation. Our results demonstrated that male skin had relatively lower baseline catalase activity, which was inhibited following acute UVB exposure in both sexes. Further analysis revealed that skin catalase activity inversely correlated with splenic Gr-1(+)CD11b(+) myeloid cell percentage. Acute UVB exposure induced Gr-1(+)CD11b(+) myeloid cell skin infiltration, which was inhibited to a greater extent in male mice by topical catalase treatment. In chronic UVB studies, we demonstrated that the percentage of splenic Gr-1(+)CD11b(+) myeloid cells was 55% higher in male tumor-bearing mice compared with their female counterparts. Together, our findings indicate that lower skin catalase activity in male mice may at least in part contribute to increased UVB-induced generation of Gr-1(+)CD11b(+) myeloid cells and subsequent skin carcinogenesis.

  9. Study on activities of vanadium (IV/V) doped TiO2(R) nanorods induced by UV and visible light

    International Nuclear Information System (INIS)

    Li, Li; Liu Chunyan; Liu Yun

    2009-01-01

    Vanadium (IV/V) doped rutile TiO 2 naonorods had been successfully synthesized through a single step hydrothermal method. The photocatalyst was characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), UV-vis diffusive reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The results showed that the doping of V ions had significant influence on the band gap energy and the surface state of TiO 2 . The photo-activities of the new catalysts were investigated under ultraviolet (UV) and visible light. The UV-photocatalytic activity of the as-prepared catalysts was hardly influenced by doping V ions; while under visible light, the samples with 1 wt% and 0.1 wt% V exhibited enhanced activity to the oxidation of methylene blue (MB) and the reduction of Cr (VI), respectively

  10. Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Triantis, T.M.; Fotiou, T. [Laboratory of Catalytic - Photocatalytic Processes (Solar Energy - Environment), Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece); Kaloudis, T. [Organic Micropollutants Laboratory, Athens Water Supply and Sewerage Company (EYDAP SA), WTP Aharnon, Menidi (Greece); Kontos, A.G.; Falaras, P. [Laboratory of Photo-redox Conversion and Storage of Solar Energy, Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece); Dionysiou, D.D.; Pelaez, M. [Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, OH 45221-0012 (United States); Hiskia, A., E-mail: hiskia@chem.demokritos.gr [Laboratory of Catalytic - Photocatalytic Processes (Solar Energy - Environment), Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer N-TiO{sub 2} exhibited effective degradation of MC-LR under UV-A, solar and visible light. Black-Right-Pointing-Pointer Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. Black-Right-Pointing-Pointer The organic nitrogen is mainly released as ammonium and nitrate ions. - Abstract: In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO{sub 2} (N-TiO{sub 2}) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO{sub 2}, Kronos and reference TiO{sub 2} nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO{sub 2} followed by N-TiO{sub 2} with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO{sub 2} nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO{sub 2} for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO{sub 2} displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO{sub 2}{sup -}, NO{sub 3}{sup -} and NH{sub 4}{sup +}) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

  11. Structural characteristics and UV-light enhanced gas sensitivity of La-doped ZnO nanoparticles

    International Nuclear Information System (INIS)

    Ge Chunqiao; Xie Changsheng; Hu Mulin; Gui Yanghai; Bai Zikui; Zeng Dawen

    2007-01-01

    La-doped ZnO nanoparticles were synthesized by sol-gel method starting from zinc acetate dihydrate, lanthanum sesquioxide, alcohol and nitric acid. The crystal structure and morphology of the nanoparticles were characterized by XRD, FESEM, respectively. The thermal decomposition behavior of the the ZnO-based xerogel was detected by TG-DSC. The results show that as-prepared nanoparticles with the hexagonal wurtzite contain the adsorbed water and some organic compounds below 300 o C, which is the key to the calcinations of the ZnO-based xerogel. Pure ZnO and La-doped ZnO thick film sensors were prepared and tested for specific sensitivity to alcohol and benzene with (and without) UV-light excitation. Among all, 10 at.%La-ZnO-based sensors are significantly sensitive to 100 ppm alcohol and 100 ppm benzene. There is an obvious enhancement of the gas-sensing performances with UV-light excitation. That is, the sensitivity to 100 ppm benzene rises twice. The observed sensitivity to alcohol and benzene could be explained with the surface adsorption theory and the conduction-band theory

  12. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

    Directory of Open Access Journals (Sweden)

    Alecia Stewart-Malone

    Full Text Available The rapid spread of quagga mussels (Dreissena rostriformis bugensis has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

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

    International Nuclear Information System (INIS)

    Estrada G, A.; Castano M, V.M.; Cruz Z, E.; Garcia F, F.

    2002-01-01

    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)

  14. Degradation Studies of Polyolefins Incorporating Transparent Nanoparticulate Zinc Oxide UV Stabilizers

    International Nuclear Information System (INIS)

    Ammala, A.; Hill, A.J.; Meakin, P.; Pas, S.J.; Turney, T.W.

    2002-01-01

    Coated and dispersed nanoparticulate zinc oxide is shown to improve ultra violet (UV) stability of polypropylene and high-density polyethylene without changing its characteristic absorption spectrum in the visible region (400-800-nm). The performance of these nanoparticulate UV stabilizers is compared to conventional hindered amine light stabilizers (HALS). QUV accelerated weathering is used to simulate long-term exposure. Positron annihilation lifetime spectroscopy (PALS) is used to provide an indication of physical and chemical changes due to accelerated weathering and is shown to have potential for detecting changes well before other techniques. Visual observation, optical microscopy, carbonyl index, yellowness index and PALS indicate that nanoparticulate zinc oxide gives superior resistance to UV degradation compared to organic HALS at appropriate loading levels

  15. Do Wild Great Tits Avoid Exposure to Light at Night?

    Directory of Open Access Journals (Sweden)

    Maaike de Jong

    Full Text Available Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their nighttime light exposure by seeking dark spots within illuminated areas. This uncertainty makes it difficult to attribute effects to a direct effect of light at night, or to indirect effects, e.g., via an effect of light at night on food availability. In this study, we aim to quantify the nocturnal light exposure of wild birds in a previously dark forest-edge habitat, experimentally illuminated with three different colors of street lighting, in comparison to a dark control. During two consecutive breeding seasons, we deployed male great tits (Parus major with a light logger measuring light intensity every five minutes over a 24h period. We found that three males from pairs breeding in brightly illuminated nest boxes close to green and red lamp posts, were not exposed to more artificial light at night than males from pairs breeding further away. This suggests, based on our limited sample size, that these males could have been avoiding light at night by choosing a roosting place with a reduced light intensity. Therefore, effects of light at night previously reported for this species in our experimental set-up might be indirect. In contrast to urban areas where light is omnipresent, bird species in non-urban areas may evade exposure to nocturnal artificial light, thereby avoiding direct consequences of light at night.

  16. Far-UV-induced dimeric photoproducts in short oligonucleotides: sequence effects

    International Nuclear Information System (INIS)

    Douki, T.; Zalizniak, T.; Cadet, J.

    1997-01-01

    Cyclobutane pyrimidine dimers and pyrimidine (6-4)pyrimidone adducts represent the two major classes of far-UV-induced DNA photoproducts. Because of the lack of appropriate detection methods for each individual photoproduct, little is known about the effect of the sequence on their formaiton. In the present work, the photoproduct distribution obtained upon exposure of a series of dinucleoside monophosphate to 254 nm light was determined. (author)

  17. Photocatalytic removal of doxycycline from aqueous solution using ZnO nano-particles: a comparison between UV-C and visible light.

    Science.gov (United States)

    Pourmoslemi, Shabnam; Mohammadi, Ali; Kobarfard, Farzad; Amini, Mohsen

    2016-10-01

    Zinc oxide nano-particles were synthesized, characterized and used for photocatalytic degradation of doxycycline using UV-C and visible light. Effects of several operational factors including initial pH of antibiotic solution, initial antibiotic concentration and ZnO nano-particles loading amount were investigated. Comparing photocatalytic degradation and mineralization of doxycycline under UV-C and visible light showed successful application of the method under both light sources. However, reaction rate was higher under UV-C irradiation, which degraded doxycycline almost completely in 5 hours, and 68% mineralization was achieved. Synthesized ZnO nano-particles were successfully applied for photocatalytic degradation of doxycycline in a pharmaceutical wastewater sample. The process was fitted to the pseudo first order kinetic model with rate constants in the range of 6-22(×10 -3 ) mg L -1 min -1 with respect to initial concentration of doxycycline under UV-C irradiation. The Langmuir-Hinshelwood model was also employed for describing the photocatalytic reaction with surface reaction kinetic constant k c and equilibrium adsorption constant K LH values calculated as 0.12 mg L -1 min -1 and 2.2 L mg -1 , respectively. Degradation of doxycycline was followed by UV-visible spectroscopy and a validated stability indicating high-performance liquid chromatography method that was developed using stressed samples of doxycycline and could selectively determine doxycycline in the presence of its degradation products. Mass spectrometry was used for determining final degradation products.

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

    Science.gov (United States)

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

    2016-01-01

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

  19. Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

    Energy Technology Data Exchange (ETDEWEB)

    Feister, Uwe [German Meteorological Service, Meteorological Observatory Lindenberg - Richard-Assmann-Observatory, Am Observatorium 12, 15848 Lindenberg (Germany); Meyer, Gabriele; Kirst, Ulrich [German Social Accident Insurance Institution for Transport and Traffic, Ottenser Hauptstrasse 54, 22765 Hamburg (Germany)

    2013-05-10

    Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels. The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.

  20. Ultraviolet light and heat source selection in captive spiny-tailed iguanas (Oplurus cuvieri)

    International Nuclear Information System (INIS)

    Dickinson, H.C.; Fa, J.E.

    1997-01-01

    Three experimental manipulations were conducted to assess the influence of heat source selection and active thermoregulation on ultraviolet (UV) light exposure in captive spiny-tailed iguanas (Oplurus cuvieri) at the Jersey Wildlife Preservation Trust. Four replicates per manipulation were conducted on six in