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Sample records for ground-based ultraviolet uv

  1. Validation of ozone monitoring instrument ultraviolet index against ground-based UV index in Kampala, Uganda.

    Science.gov (United States)

    Muyimbwa, Dennis; Dahlback, Arne; Ssenyonga, Taddeo; Chen, Yi-Chun; Stamnes, Jakob J; Frette, Øyvind; Hamre, Børge

    2015-10-01

    The Ozone Monitoring Instrument (OMI) overpass solar ultraviolet (UV) indices have been validated against the ground-based UV indices derived from Norwegian Institute for Air Research UV measurements in Kampala (0.31° N, 32.58° E, 1200 m), Uganda for the period between 2005 and 2014. An excessive use of old cars, which would imply a high loading of absorbing aerosols, could cause the OMI retrieval algorithm to overestimate the surface UV irradiances. The UV index values were found to follow a seasonal pattern with maximum values in March and October. Under all-sky conditions, the OMI retrieval algorithm was found to overestimate the UV index values with a mean bias of about 28%. When only days with radiation modification factor greater than or equal to 65%, 70%, 75%, and 80% were considered, the mean bias between ground-based and OMI overpass UV index values was reduced to 8%, 5%, 3%, and 1%, respectively. The overestimation of the UV index by the OMI retrieval algorithm was found to be mainly due to clouds and aerosols.

  2. Validation of OMI UV measurements against ground-based measurements at a station in Kampala, Uganda

    Science.gov (United States)

    Muyimbwa, Dennis; Dahlback, Arne; Stamnes, Jakob; Hamre, Børge; Frette, Øyvind; Ssenyonga, Taddeo; Chen, Yi-Chun

    2015-04-01

    We present solar ultraviolet (UV) irradiance data measured with a NILU-UV instrument at a ground site in Kampala (0.31°N, 32.58°E), Uganda for the period 2005-2014. The data were analyzed and compared with UV irradiances inferred from the Ozone Monitoring Instrument (OMI) for the same period. Kampala is located on the shores of lake Victoria, Africa's largest fresh water lake, which may influence the climate and weather conditions of the region. Also, there is an excessive use of worn cars, which may contribute to a high anthropogenic loading of absorbing aerosols. The OMI surface UV algorithm does not account for absorbing aerosols, which may lead to systematic overestimation of surface UV irradiances inferred from OMI satellite data. We retrieved UV index values from OMI UV irradiances and validated them against the ground-based UV index values obtained from NILU-UV measurements. The UV index values were found to follow a seasonal pattern similar to that of the clouds and the rainfall. OMI inferred UV index values were overestimated with a mean bias of about 28% under all-sky conditions, but the mean bias was reduced to about 8% under clear-sky conditions when only days with radiation modification factor (RMF) greater than 65% were considered. However, when days with RMF greater than 70, 75, and 80% were considered, OMI inferred UV index values were found to agree with the ground-based UV index values to within 5, 3, and 1%, respectively. In the validation we identified clouds/aerosols, which were present in 88% of the measurements, as the main cause of OMI inferred overestimation of the UV index.

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

    Science.gov (United States)

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

    2017-06-01

    This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS

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

    Directory of Open Access Journals (Sweden)

    M.-M. Zempila

    2017-06-01

    Full Text Available This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4 UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh, in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990 and with a very low bias (0.000 to 0.011 in absolute units proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5

  5. Ultraviolet radiation modelling from ground-based and satellite measurements on Reunion Island, southern tropics

    Directory of Open Access Journals (Sweden)

    K. Lamy

    2018-01-01

    Full Text Available Surface ultraviolet radiation (SUR is not an increasing concern after the implementation of the Montreal Protocol and the recovery of the ozone layer Morgenstern et al.(2008. However, large uncertainties remain in the prediction of future changes of SUR Bais et al.(2015. Several studies pointed out that UV-B impacts the biosphere Erickson et al.(2015, especially the aquatic system, which plays a central part in the biogeochemical cycle Hader et al.(2007. It can affect phytoplankton productivity Smith and Cullen(1995. This influence can result in either positive or negative feedback on climate (Zepp et al., 2007. Global circulation model simulations predict an acceleration of the Brewer-Dobson circulation over the next century (Butchart, 2014, which would lead to a decrease in ozone levels in the tropics and an enhancement at higher latitudes (Hegglin and Shepherd, 2009. Reunion Island is located in the tropics (21° S, 55° E, in a part of the world where the amount of ozone in the ozone column is naturally low. In addition, this island is mountainous and the marine atmosphere is often clean with low aerosol concentrations. Thus, measurements show much higher SUR than at other sites at the same latitude or at midlatitudes. Ground-based measurements of SUR have been taken on Reunion Island by a Bentham DTMc300 spectroradiometer since 2009. This instrument is affiliated with the Network for the Detection of Atmospheric Composition Change (NDACC. In order to quantify the future evolution of SUR in the tropics, it is necessary to validate a model against present observations. This study is designed to be a preliminary parametric and sensitivity study of SUR modelling in the tropics. We developed a local parameterisation using the Tropospheric Ultraviolet and Visible Model (TUV; Madronich, 1993 and compared the output of TUV to multiple years of Bentham spectral measurements. This comparison started in early 2009 and continued until 2016

  6. Ultraviolet radiation modelling from ground-based and satellite measurements on Reunion Island, southern tropics

    Science.gov (United States)

    Lamy, Kévin; Portafaix, Thierry; Brogniez, Colette; Godin-Beekmann, Sophie; Bencherif, Hassan; Morel, Béatrice; Pazmino, Andrea; Metzger, Jean Marc; Auriol, Frédérique; Deroo, Christine; Duflot, Valentin; Goloub, Philippe; Long, Charles N.

    2018-01-01

    Surface ultraviolet radiation (SUR) is not an increasing concern after the implementation of the Montreal Protocol and the recovery of the ozone layer (Morgenstern et al., 2008). However, large uncertainties remain in the prediction of future changes of SUR (Bais et al., 2015). Several studies pointed out that UV-B impacts the biosphere (Erickson et al., 2015), especially the aquatic system, which plays a central part in the biogeochemical cycle (Hader et al., 2007). It can affect phytoplankton productivity (Smith and Cullen, 1995). This influence can result in either positive or negative feedback on climate (Zepp et al., 2007). Global circulation model simulations predict an acceleration of the Brewer-Dobson circulation over the next century (Butchart, 2014), which would lead to a decrease in ozone levels in the tropics and an enhancement at higher latitudes (Hegglin and Shepherd, 2009). Reunion Island is located in the tropics (21° S, 55° E), in a part of the world where the amount of ozone in the ozone column is naturally low. In addition, this island is mountainous and the marine atmosphere is often clean with low aerosol concentrations. Thus, measurements show much higher SUR than at other sites at the same latitude or at midlatitudes. Ground-based measurements of SUR have been taken on Reunion Island by a Bentham DTMc300 spectroradiometer since 2009. This instrument is affiliated with the Network for the Detection of Atmospheric Composition Change (NDACC). In order to quantify the future evolution of SUR in the tropics, it is necessary to validate a model against present observations. This study is designed to be a preliminary parametric and sensitivity study of SUR modelling in the tropics. We developed a local parameterisation using the Tropospheric Ultraviolet and Visible Model (TUV; Madronich, 1993) and compared the output of TUV to multiple years of Bentham spectral measurements. This comparison started in early 2009 and continued until 2016. Only

  7. 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.

  8. Ozone ground-based measurements by the GASCOD near-UV and visible DOAS system

    Science.gov (United States)

    Giovanelli, G.; Bonasoni, P.; Cervino, M.; Evangelisti, F.; Ravegnani, F.

    1994-01-01

    GASCOD, a near-ultraviolet and visible differential optical spectrometer, was developed at CNR's FISBAT Institute in Bologna, Italy, and first tested at Terra Nova Bay station in Antarctica (74.6 deg S, 164.6 deg E) during the summer expeditions 1988-1990 of PNRA (PNRA is the national research program in Antarctica, 'Programma Nazionale di Ricerche in Atartide'). A comparison with coincident O3 total column measurements taken in the same Antarctic area is presented, as is another comparison performed in Italy. Also introduced is an updated model for solar zenith measurements taken from a ground-based, upward-looking GASCOD spectrometer, which was employed for the 1991-92 winter campaign at Aer-Ostersund in Sweden (63.3 deg N, 13.1 deg E) during AESOE (European Arctic Stratospheric Ozone Experiment). The GASCOD can examine the spectra from 300 to 700 nm, in 50 nm steps, by moving the spectrometer's grating. At present, it takes measurements of solar zenith radiation in the 310-342 nm range for O3 and in the 405-463 nm range for NO2.

  9. PSC and volcanic aerosol routine observations in Antarctica by UV-visible ground-based spectrometry

    Science.gov (United States)

    Sarkissian, A.; Pommereau, J. P.; Goutail, F.

    1994-01-01

    Polar statospheric clouds (PSC) and stratospheric aerosol can be observed by ground-based UV-visible spectrometry by looking at the variation of the color of the sky during twilight. A radiative transfer model shows that reddenings are caused by high altitude (22-28 km) thin layers of scatterers, while low altitude (12-20 km) thick ones result in blueings. The color index method applied on 4 years of observations at Dumont d'Urville (67 deg S), from 1988 to 1991, shows that probably because the station is located at the edge of the vortex, dense PSC are uncommon. More unexpected is the existence of a systematic seasonal variation of the color of the twilight sky - bluer at spring - which reveals the formation of a dense scattering layer at or just above the tropopause at the end of the winter. Large scattering layers are reported above the station in 1991, first in August around 12-14 km, later in September at 22-24 km. They are attributed to volcanic aerosol from Mt Hudson and Mt Pinatubo respectively, which erupted in 1991. Inspection of the data shows that the lowest entered rapidly into the polar vortex but not the highest which remained outside, demonstrating that the vortex was isolated at 22-26 km.

  10. Changes in ground-based solar ultraviolet radiation during fire episodes: a case study

    CSIR Research Space (South Africa)

    Wright, CY

    2013-09-01

    Full Text Available Solar ultraviolet radiation (UVR) levels are affected by airborne aerosols, such as particles and gases released during biomass burning events. Two large-scale fires in South Africa were identified and selected based on their proximity to solar UVR...

  11. Recent advances in ground-based ultraviolet remote sensing of volcanic SO2 fluxes

    Directory of Open Access Journals (Sweden)

    Euripides P. Kantzas

    2011-06-01

    Full Text Available Measurements of volcanic SO2 emission rates have been the mainstay of remote-sensing volcanic gas geochemistry for almost four decades, and they have contributed significantly to our understanding of volcanic systems and their impact upon the atmosphere. The last ten years have brought step-change improvements in the instrumentation applied to these observations, which began with the application of miniature ultraviolet spectrometers that were deployed in scanning and traverse configurations, with differential optical absorption spectroscopy evaluation routines. This study catalogs the more recent empirical developments, including: ultraviolet cameras; wide-angle field-of-view differential optical absorption spectroscopy systems; advances in scanning operations, including tomography; and improved understanding of errors, in particular concerning radiative transfer. Furthermore, the outcomes of field deployments of sensors during the last decade are documented, with respect to improving our understanding of volcanic dynamics and degassing into the atmosphere.

  12. Ultraviolet (UV) Disinfection for Drinking Water Systems

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    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  13. The retrieval of profile and chemical information from ground-based UV-visible spectroscopic measurements

    International Nuclear Information System (INIS)

    Schofield, R.; Connor, B.J.; Kreher, K.; Johnston, P.V.; Rodgers, C.D.

    2004-01-01

    An algorithm has been developed to retrieve altitude information at different diurnal stages for trace gas species by combining direct-sun and zenith-sky UV-visible differential slant column density (DSCD) measurements. DSCDs are derived here using differential optical absorption spectroscopy. Combining the complementary zenith-sky measurements (sensitive to the stratosphere) with direct-sun measurements (sensitive to the troposphere) allows this vertical distinction. Trace gas species such as BrO and NO 2 have vertical profiles with strong diurnal dependence. Information about the diurnal variation is simultaneously retrieved with the altitude distribution of the trace gas. The retrieval is a formal optimal estimation profile retrieval, allowing a complete assessment of information content and errors

  14. The World Space Observatory Ultraviolet (WSO-UV), as a bridge to future UV astronomy

    Science.gov (United States)

    Shustov, B.; Gómez de Castro, A. I.; Sachkov, M.; Vallejo, J. C.; Marcos-Arenal, P.; Kanev, E.; Savanov, I.; Shugarov, A.; Sichevskii, S.

    2018-04-01

    Ultraviolet (UV) astronomy is a vital branch of space astronomy. Many dozens of short-term UV-experiments in space, as well as long-term observatories, have brought a very important knowledge on the physics and chemistry of the Universe during the last decades. Unfortunately, no large UV-observatories are planned to be launched by most of space agencies in the coming 10-15 years. Conversely, the large UVOIR observatories of the future will appear not earlier than in 2030s. This paper briefly describes the projects that have been proposed by various groups. We conclude that the World Space Observatory-Ultraviolet (WSO-UV) will be the only 2-m class UV telescope with capabilities similar to those of the HST for the next decade. The WSO-UV has been described in detail in previous publications, and this paper updates the main characteristics of its instruments and the current state of the whole project. It also addresses the major science topics that have been included in the core program of the WSO-UV, making this core program very relevant to the current state of the UV-astronomy. Finally, we also present here the ground segment architecture that will implement this program.

  15. Ultraviolet (UV) disinfection of grey water: particle size effects.

    Science.gov (United States)

    Winward, G P; Avery, L M; Stephenson, T; Jefferson, B

    2008-02-01

    The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

  16. 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

  17. 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.

  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. Ultraviolet-B-effects on plants: Spectra of harmful effects, primary damage and UV protective mechanisms

    International Nuclear Information System (INIS)

    Wellmann, E.; Beggs, C.; Moehle, B.; Schneider-Ziebert, U.; Steinmetz, V.; Koch, U.

    1986-01-01

    In two model systems of higher plants, damage caused by ultraviolet-B-radiation was analysed as to its mechanism of action and the spectral quantum efficiency. These investigations were to provide information on the relevance of such UV effects in cases of increased ultraviolet-B-irradiation owing to the destruction of ozone. The results indicate the very high tolerance of the plants to ultraviolet-B-radiation which obviously is the result of very effective protective mechanisms, and show at the same time that potential damage must already be reckoned with, given the current share of ultraviolet-B-radiation in solar radiation. Should ultraviolet-B-radiation be increased, then indirect damage to the plant from the destruction of ultraviolet protective mechanisms through UV-B-radiation will probably constitute a particular risk. (orig./MG) [de

  20. 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.

  1. Retrieval of nitrogen dioxide stratospheric profiles from ground-based zenith-sky UV-visible observations: validation of the technique through correlative comparisons

    Directory of Open Access Journals (Sweden)

    F. Hendrick

    2004-01-01

    Full Text Available A retrieval algorithm based on the Optimal Estimation Method (OEM has been developed in order to provide vertical distributions of NO2 in the stratosphere from ground-based (GB zenith-sky UV-visible observations. It has been applied to observational data sets from the NDSC (Network for Detection of Stratospheric Change stations of Harestua (60° N, 10° E and Andøya (69° N, 16° E in Norway. The information content and retrieval errors have been analyzed following a formalism used for characterizing ozone profiles retrieved from solar infrared absorption spectra. In order to validate the technique, the retrieved NO2 vertical profiles and columns have been compared to correlative balloon and satellite observations. Such extensive validation of the profile and column retrievals was not reported in previously published work on the profiling from GB UV-visible measurements. A good agreement - generally better than 25% - has been found with the SAOZ (Système d'Analyse par Observations Zénithales and DOAS (Differential Optical Absorption Spectroscopy balloons. A similar agreement has been reached with correlative satellite data from the HALogen Occultation Experiment (HALOE and Polar Ozone and Aerosol Measurement (POAM III instruments above 25km of altitude. Below 25km, a systematic underestimation - by up to 40% in some cases - of both HALOE and POAM III profiles by our GB profile retrievals has been observed, pointing out more likely a limitation of both satellite instruments at these altitudes. We have concluded that our study strengthens our confidence in the reliability of the retrieval of vertical distribution information from GB UV-visible observations and offers new perspectives in the use of GB UV-visible network data for validation purposes.

  2. Comets in UV

    Science.gov (United States)

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

    2018-04-01

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

  3. Ultraviolet (UV)-reflective paint with ultraviolet germicidal irradiation (UVGI) improves decontamination of nosocomial bacteria on hospital room surfaces.

    Science.gov (United States)

    Jelden, Katelyn C; Gibbs, Shawn G; Smith, Philip W; Hewlett, Angela L; Iwen, Peter C; Schmid, Kendra K; Lowe, John J

    2017-06-01

    An ultraviolet germicidal irradiation (UVGI) generator (the TORCH, ClorDiSys Solutions, Inc.) was used to compare the disinfection of surface coupons (plastic from a bedrail, stainless steel, and chrome-plated light switch cover) in a hospital room with walls coated with ultraviolet (UV)-reflective paint (Lumacept) or standard paint. Each surface coupon was inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus faecalis (VRE), placed at 6 different sites within a hospital room coated with UV-reflective paint or standard paint, and treated by 10 min UVC exposure (UVC dose of 0-688 mJ/cm 2 between sites with standard paint and 0-553 mJ/cm 2 with UV-reflective paint) in 8 total trials. Aggregated MRSA concentrations on plastic bedrail surface coupons were reduced on average by 3.0 log 10 (1.8 log 10 Geometric Standard Deviation [GSD]) with standard paint and 4.3 log 10 (1.3 log 10 GSD) with UV-reflective paint (p = 0.0005) with no significant reduction differences between paints on stainless steel and chrome. Average VRE concentrations were reduced by ≥4.9 log 10 (surface types with UV-reflective paint and ≤4.1 log 10 (hospital bed from the UVGI generator, MRSA concentrations on average were reduced by 1.3 log 10 (1.7 log 10 GSD) with standard paint and 4.7 log 10 (1.3 log 10 GSD) with UV-reflective paint (p hospital room walls with UV-reflective paint enhanced UVGI disinfection of nosocomial bacteria on various surfaces compared to standard paint, particularly at a surface placement site indirectly exposed to UVC light.

  4. How do environmental and behavioral factors impact ultraviolet radiation effects on health: the RISC-UV Project

    Science.gov (United States)

    Correa, M. P.; Godin-Beekmann, S.; Haeffelin, M.; Saiag, P.; Mahe, E.; Brogniez, C.; Dupont, J. C.; Pazmiño, A.; Auriol, F.; Bonnel, B.

    2009-04-01

    UV radiation data obtained at various spatial scales (satellite, ground-based and spot measurements) by a variety of measuring systems. Moreover a set of atmospheric parameters (total ozone column, the vertical profile and optical thickness of aerosols, cloud cover and solar albedo) related to UV radiation is also collected. Material: The instrumental set consisted of several instruments for: 1) UV radiation measurements (a spectroradiometer, UV-A, UV-B, Erythemal UV and broadband solar pyranometers); 2) cloud, ozone and aerosol observations (photometer, Lidar and radiometers); and 3) personal monitors for UV index measurements, as handhelds, watches and mini-station. Results: Measurements performed in cloudy and sunny days around noon local time (± 1h) showed mean values of 3.3 ± 1.0 UVI, and the maximum UVI was 5.5 at noon on a clear sky day (September 14). The influence of cirrus clouds and aerosols radiation attenuation is currently studied on several case studies. From the mean UVI values, we estimated the time of necessary exposure for the induction of erythema of the skin and for the synthesis 1000 UI of vitamin D per day (1000 UI). (McKenzie et al., 2008). Preliminary results show that around solar noon (between 9 and 12 UTC that is 11 and 14 local time), on the one hand, about 45 min of exposure is required to cause skin redness and consequently lead to harmful effects on the human health. On the other hand, this exposure can be insufficient to lead to beneficial effects if we consider only the generally exposed parts of the body, as the hands and the face. It is only in the extreme conditions - exposure of the whole body - that the synthesis of the vitamin D can be done in 10 to 20 minutes. Otherwise an exposure during several hours is necessary. These results are particularly interesting with respect to possible problems of lack of vitamin D in the French population, mainly rickets (children) and osteosporosis (old persons), as well as other diseases

  5. 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.

  6. Ultraviolet /UV/ sensitive phosphors for silicon imaging detectors

    Science.gov (United States)

    Viehmann, W.; Cowens, M. W.; Butner, C. L.

    1981-01-01

    The fluorescence properties of UV sensitive organic phosphors and the radiometric properties of phosphor coated silicon detectors in the VUV, UV, and visible wavelengths are described. With evaporated films of coronene and liumogen, effective quantum efficiencies of up to 20% have been achieved on silicon photodiodes in the vacuum UV. With thin films of methylmethacrylate (acrylic), which are doped with organic laser dyes and deposited from solution, detector quantum efficiencies of the order of 15% for wavelengths of 120-165 nm and of 40% for wavelengths above 190 nm have been obtained. The phosphor coatings also act as antireflection coatings and thereby enhance the response of coated devices throughout the visible and near IR.

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

    African Journals Online (AJOL)

    Prof. Ogunji

    The effects of UV-radiation on the bacterial load and yeast viability of palm wine were ... shelf life due to the uncontrolled metabolic activities of yeast and bacteria. .... Process. Biochemistry International 8:23-220. Okafor, N. (2007). Palm Wine ...

  8. Retrieval of NO2 stratospheric profiles from ground-based zenith-sky uv-visible measurements at 60°N

    Science.gov (United States)

    Hendrick, F.; van Roozendael, M.; Lambert, J.-C.; Fayt, C.; Hermans, C.; de Mazière, M.

    2003-04-01

    Nitrogen dioxide (NO_2) plays an important role in controlling ozone abundances in the stratosphere, either directly through the NOx (NO+NO_2) catalytic cycle, either indirectly by reaction with the radical ClO to form the reservoir species ClONO_2. In this presentation, NO_2 stratospheric profiles are retrieved from ground-based UV-visible NO_2 slant column abundances measured since 1998 at the complementary NDSC station of Harestua (Norway, 60^oN). The retrieval algorithm is based on the Rodgers optimal estimation inversion method and a forward model consisting in the IASB-BIRA stacked box photochemical model PSCBOX coupled to the radiative transfer package UVspec/DISORT. This algorithm has been applied to a set of about 50 sunrises and sunsets for which spatially and temporally coincident NO_2 measurements made by the HALOE (Halogen Occultation Experiment) instrument on board the Upper Atmosphere Research Satellite (UARS) are available. The consistency between retrieved and HALOE profiles is discussed in term of the different seasonal conditions investigated which are spring with and without chlorine activation, summer, and fall.

  9. Issues in Quantitative Analysis of Ultraviolet Imager (UV) Data: Airglow

    Science.gov (United States)

    Germany, G. A.; Richards, P. G.; Spann, J. F.; Brittnacher, M. J.; Parks, G. K.

    1999-01-01

    The GGS Ultraviolet Imager (UVI) has proven to be especially valuable in correlative substorm, auroral morphology, and extended statistical studies of the auroral regions. Such studies are based on knowledge of the location, spatial, and temporal behavior of auroral emissions. More quantitative studies, based on absolute radiometric intensities from UVI images, require a more intimate knowledge of the instrument behavior and data processing requirements and are inherently more difficult than studies based on relative knowledge of the oval location. In this study, UVI airglow observations are analyzed and compared with model predictions to illustrate issues that arise in quantitative analysis of UVI images. These issues include instrument calibration, long term changes in sensitivity, and imager flat field response as well as proper background correction. Airglow emissions are chosen for this study because of their relatively straightforward modeling requirements and because of their implications for thermospheric compositional studies. The analysis issues discussed here, however, are identical to those faced in quantitative auroral studies.

  10. ULTRAVIOLET RAMAN SPECTRAL SIGNATURE ACQUISITION: UV RAMAN SPECTRAL FINGERPRINTS.

    Energy Technology Data Exchange (ETDEWEB)

    SEDLACEK,III, A.J.FINFROCK,C.

    2002-09-01

    As a member of the science-support part of the ITT-lead LISA development program, BNL is tasked with the acquisition of UV Raman spectral fingerprints and associated scattering cross-sections for those chemicals-of-interest to the program's sponsor. In support of this role, the present report contains the first installment of UV Raman spectral fingerprint data on the initial subset of chemicals. Because of the unique nature associated with the acquisition of spectral fingerprints for use in spectral pattern matching algorithms (i.e., CLS, PLS, ANN) great care has been undertaken to maximize the signal-to-noise and to minimize unnecessary spectral subtractions, in an effort to provide the highest quality spectral fingerprints. This report is divided into 4 sections. The first is an Experimental section that outlines how the Raman spectra are performed. This is then followed by a section on Sample Handling. Following this, the spectral fingerprints are presented in the Results section where the data reduction process is outlined. Finally, a Photographs section is included.

  11. Design of tunable ultraviolet (UV) absorbance by controlling the Agsbnd Al co-sputtering deposition

    Science.gov (United States)

    Zhang, Xin-Yuan; Chen, Lei; Wang, Yaxin; Zhang, Yongjun; Yang, Jinghai; Choi, Hyun Chul; Jung, Young Mee

    2018-05-01

    Changing the structure and composition of a material can alter its properties; hence, the controlled fabrication of metal nanostructures plays a key role in a wide range of applications. In this study, the structure of Agsbnd Al ordered arrays fabricated by co-sputtering deposition onto a monolayer colloidal crystal significantly increased its ultraviolet (UV) absorbance owing to a tunable localized surface plasmon resonance (LSPR) effect. By increasing the spacing between two nanospheres and the content of aluminum, absorbance in the UV region could be changed from UVA (320-400 nm) to UVC (200-275 nm), and the LSPR peak in the visible region gradually shifted to the UV region. This provides the potential for surface-enhanced Raman scattering (SERS) in both the UV and visible regions.

  12. Role of ultraviolet (UV) disinfection in infection control and environmental cleaning.

    Science.gov (United States)

    Qureshi, Zubair; Yassin, Mohamed H

    2013-06-01

    Ultraviolet (UV) radiation is capable of disinfecting surfaces, water and air. The UV technology was used for many years. However, safer and more effective delivery systems of UV radiation, make it a very useful option for disinfection. Effective disinfection of environmental surfaces is a key step in the prevention of spread of infectious agents. The traditional manual cleaning is essential in assuring adequate elimination of contamination. However, terminal cleaning is frequently suboptimal or unpredictable in many circumstances. UV-C radiation is an adjunctive disinfectant new technology that could kill a wide array of microorganisms including both vegetative and spore forming pathogens. The technology is getting more affordable and has produced consistent reproducible significant reduction of bacterial contamination.

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

    Science.gov (United States)

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

    2017-06-01

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

  14. Analysis of UV-excited fluorochromes by flow cytometry using near-ultraviolet laser diodes.

    Science.gov (United States)

    Telford, William G

    2004-09-01

    Violet laser diodes have become common and reliable laser sources for benchtop flow cytometers. While these lasers are very useful for a variety of violet and some ultraviolet-excited fluorochromes (e.g., DAPI), they do not efficiently excite most UV-stimulated probes. In this study, the next generation of InGaN near-UV laser diodes (NUVLDs) emitting in the 370-375-nm range have been evaluated as laser sources for cuvette-based flow cytometers. Several NUVLDs, ranging in wavelength from 370 to 374 nm and in power level from 1.5 to 10 mW, were mounted on a BD Biosciences LSR II and evaluated for their ability to excite cells labeled with the UV DNA binding dye DAPI, several UV phenotyping fluorochromes (including Alexa Fluor 350, Marina Blue, and quantum dots), and the fluorescent calcium chelator indo-1. NUVLDs at the 8-10-mW power range gave detection sensitivity levels comparable to more powerful solid-state and ion laser sources, using low-fluorescence microsphere beads as measurement standards. NUVLDs at all tested power levels allowed extremely high-resolution DAPI cell cycle analysis, and sources in the 8-10-mW power range excited Alexa Fluor 350, Marina Blue, and a variety of quantum dots at virtually the same signal-to-noise ratios as more powerful UV sources. These evaluations indicate that near-UV laser diodes installed on a cuvette-based flow cytometer performed nearly as well as more powerful solid-state UV lasers on the same instrumentation, and comparably to more powerful ion lasers on a jet-in-air system, and. Despite their limited power, integration of these small and inexpensive lasers into benchtop flow cytometers should allow the use of flow cytometric applications requiring UV excitation on a wide variety of instruments. Copyright 2004 Wiley-Liss, Inc.

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

    International Nuclear Information System (INIS)

    Laakso, K.; Huttunen, S.

    1998-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Matias Fábio

    2016-01-01

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

  17. Ultraviolet/visible and Fourier transform infrared spectroscopic investigations of organic–inorganic hybrid layers for UV protection

    Energy Technology Data Exchange (ETDEWEB)

    Präfke, Christiane, E-mail: christiane.praefke@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena (Germany); Schulz, Ulrike, E-mail: ulrike.schulz@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Kaiser, Norbert, E-mail: norbert.kaiser@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Tünnermann, Andreas, E-mail: andreas.tuennermann@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena (Germany)

    2013-04-01

    A study of vacuum-deposited organic–inorganic hybrid coatings for ultraviolet (UV) protection of polycarbonate is presented. For this purpose, UV-absorbing organic molecules were embedded in a silica matrix by thermal co-evaporation. Typical UV absorbers, namely a benzotriazole, a hydroxyphenyltriazine, and a cyanoacrylate, were used as organic materials. The hybrid layers were investigated by means of ultraviolet/visible (UV/VIS) and Fourier transform infrared spectroscopy (FTIR) concerning their UV/VIS absorption properties and the influence of the silica network on the organic molecules. The porosity and silica–organic interactions are discussed with reference to the infrared spectra. UV irradiation experiments were carried out to demonstrate the UV protection ability of the hybrid layers. Hybrid layers containing the hydroxyphenyltriazine compound showed the best results. - Highlights: ► Vacuum deposited organic–inorganic UV protective coatings for polycarbonate ► Thermal co-evaporation of organic UV absorbing compounds with silica ► Matrix materials and the absorber concentration influence the absorption behavior. ► The coatings on PC show improved UV stability under artificial irradiation. ► The hydroxyphenyltriazine–silica layer shows best UV protection results.

  18. UV-POSIT: Web-Based Tools for Rapid and Facile Structural Interpretation of Ultraviolet Photodissociation (UVPD) Mass Spectra

    Science.gov (United States)

    Rosenberg, Jake; Parker, W. Ryan; Cammarata, Michael B.; Brodbelt, Jennifer S.

    2018-04-01

    UV-POSIT (Ultraviolet Photodissociation Online Structure Interrogation Tools) is a suite of web-based tools designed to facilitate the rapid interpretation of data from native mass spectrometry experiments making use of 193 nm ultraviolet photodissociation (UVPD). The suite includes four separate utilities which assist in the calculation of fragment ion abundances as a function of backbone cleavage sites and sequence position; the localization of charge sites in intact proteins; the calculation of hydrogen elimination propensity for a-type fragment ions; and mass-offset searching of UVPD spectra to identify unknown modifications and assess false positive fragment identifications. UV-POSIT is implemented as a Python/Flask web application hosted at http://uv-posit.cm.utexas.edu. UV-POSIT is available under the MIT license, and the source code is available at https://github.com/jarosenb/UV_POSIT. [Figure not available: see fulltext.

  19. UV-POSIT: Web-Based Tools for Rapid and Facile Structural Interpretation of Ultraviolet Photodissociation (UVPD) Mass Spectra.

    Science.gov (United States)

    Rosenberg, Jake; Parker, W Ryan; Cammarata, Michael B; Brodbelt, Jennifer S

    2018-04-06

    UV-POSIT (Ultraviolet Photodissociation Online Structure Interrogation Tools) is a suite of web-based tools designed to facilitate the rapid interpretation of data from native mass spectrometry experiments making use of 193 nm ultraviolet photodissociation (UVPD). The suite includes four separate utilities which assist in the calculation of fragment ion abundances as a function of backbone cleavage sites and sequence position; the localization of charge sites in intact proteins; the calculation of hydrogen elimination propensity for a-type fragment ions; and mass-offset searching of UVPD spectra to identify unknown modifications and assess false positive fragment identifications. UV-POSIT is implemented as a Python/Flask web application hosted at http://uv-posit.cm.utexas.edu . UV-POSIT is available under the MIT license, and the source code is available at https://github.com/jarosenb/UV_POSIT . Graphical Abstract.

  20. The ground based plan

    International Nuclear Information System (INIS)

    1989-01-01

    The paper presents a report of ''The Ground Based Plan'' of the United Kingdom Science and Engineering Research Council. The ground based plan is a plan for research in astronomy and planetary science by ground based techniques. The contents of the report contains a description of:- the scientific objectives and technical requirements (the basis for the Plan), the present organisation and funding for the ground based programme, the Plan, the main scientific features and the further objectives of the Plan. (U.K.)

  1. Implementation of innovative pulsed xenon ultraviolet (PX-UV environmental cleaning in an acute care hospital

    Directory of Open Access Journals (Sweden)

    Fornwalt L

    2014-01-01

    Full Text Available Lori Fornwalt,1 Brad Riddell1,2 1Departments of Infection Prevention and Environmental Services, Trinity Medical Centre, Birmingham, AL, 2Environmental Services, Medical University of South Carolina, Charleston, SC, USA Abstract: It is widely acknowledged that the hospital environment is an important reservoir for many of the pathogenic microbes associated with health care-associated infections (HAIs. Environmental cleaning plays an important role in the prevention and containment of HAIs, in patient safety, and the overall experience of health care facilities. New technologies, such as pulsed xenon ultraviolet (PX-UV light systems are an innovative development for enhanced cleaning and decontamination of hospital environments. A portable PX-UV disinfection device delivers pulsed UV light to destroy microbial pathogens and spores, and can be used in conjunction with manual environmental cleaning. In addition, this technology facilitates thorough disinfection of hospital rooms in 10–15 minutes. The current study was conducted to evaluate whether the introduction of the PX-UV device had a positive impact on patient satisfaction. Satisfaction was measured using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS survey. In 2011, prior to the introduction of the PX-UV system, patient HCAHPS scores for cleanliness averaged 75.75%. In the first full quarter after enhanced cleaning of the facility was introduced, this improved to 83%. Overall scores for the hospital rose from 76% (first quarter, 2011 to 87.6% (fourth quarter, 2012. As a result of this improvement, the hospital received 1% of at-risk reimbursement from the inpatient prospective payment system as well as additional funding. Cleanliness of the hospital environment is one of the questions included in the HCAHPS survey and one measure of patient satisfaction. After the introduction of the PX-UV system, the score for cleanliness and the overall rating of the

  2. Drinking water disinfection by means of ultraviolet radiation. Desinfektion von Trinkwasser durch UV-Bestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Gelzhaeuser, P; Bewig, F; Holm, K; Kryschi, R; Reich, G; Steuer, W

    1985-01-01

    The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice.

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

    Science.gov (United States)

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

    2014-08-15

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

  4. 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

  5. Hope and challenge: the importance of ultraviolet (UV) radiation for cutaneous vitamin D synthesis and skin cancer.

    Science.gov (United States)

    Reichrath, Jörg; Reichrath, Sandra

    2012-01-01

    Abstract Solar ultraviolet (UV)-radiation is the most important environmental risk factor for the development of non-melanoma skin cancer (most importantly basal and squamous cell carcinomas), that represent the most common malignancies in Caucasian populations. To prevent these malignancies, public health campaigns were developed to improve the awareness of the general population of the role of UV-radiation. The requirements of vitamin D is mainly achieved by UV-B-induced cutaneous photosynthesis, and the vitamin D-mediated positive effects of UV-radiation were not always adequately considered in these campaigns; a strict "no sun policy" might lead to vitamin D-deficiency. This dilemma represents a serious problem in many populations, for an association of vitamin D-deficiency and multiple independent diseases has been convincingly demonstrated. It is crucial that guidelines for UV-exposure (e.g. in skin cancer prevention campaigns) consider these facts and give recommendations how to prevent vitamin D-deficiency. In this review, we analyze the present literature to help developing well-balanced guidelines on UV-protection that ensure an adequate vitamin D-status without increasing the risk to develop UV-induced skin cancer.

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

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  7. Luminescence of Ce3+ at two different sites in ?-Sr2P2O7 under vacuum ultraviolet-UV and x-ray excitation

    NARCIS (Netherlands)

    Hou, D.; Han, B.; Chen, W.; Liang, H.; Su, Q.; Dorenbos, P.; Huang, Y.; Gao, Z.; Tao, Y.

    2010-01-01

    A series of Ce3+ doped ?-Sr2?2xCexNaxP2O7 phosphor compounds has been prepared using a high-temperature solid-state reaction technique. The luminescence properties under vacuum ultraviolet-UV and x-ray excitation were studied. Luminescence spectra reveal three UV-emitting peaks at about 310, 330,

  8. 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)

  9. Space- and Ground-based Coronal Spectro-Polarimetry

    Science.gov (United States)

    Fineschi, Silvano; Bemporad, Alessandro; Rybak, Jan; Capobianco, Gerardo

    This presentation gives an overview of the near-future perspectives of ultraviolet and visible-light spectro-polarimetric instrumentation for probing coronal magnetism from space-based and ground-based observatories. Spectro-polarimetric imaging of coronal emission-lines in the visible-light wavelength-band provides an important diagnostics tool of the coronal magnetism. The interpretation in terms of Hanle and Zeeman effect of the line-polarization in forbidden emission-lines yields information on the direction and strength of the coronal magnetic field. As study case, this presentation will describe the Torino Coronal Magnetograph (CorMag) for the spectro-polarimetric observation of the FeXIV, 530.3 nm, forbidden emission-line. CorMag - consisting of a Liquid Crystal (LC) Lyot filter and a LC linear polarimeter - has been recently installed on the Lomnicky Peak Observatory 20cm Zeiss coronagraph. The preliminary results from CorMag will be presented. The linear polarization by resonance scattering of coronal permitted line-emission in the ultraviolet (UV)can be modified by magnetic fields through the Hanle effect. Space-based UV spectro-polarimeters would provide an additional tool for the disgnostics of coronal magnetism. As a case study of space-borne UV spectro-polarimeters, this presentation will describe the future upgrade of the Sounding-rocket Coronagraphic Experiment (SCORE) to include the capability of imaging polarimetry of the HI Lyman-alpha, 121.6 nm. SCORE is a multi-wavelength imager for the emission-lines, HeII 30.4 nm and HI 121.6 nm, and visible-light broad-band emission of the polarized K-corona. SCORE has flown successfully in 2009. This presentation will describe how in future re-flights SCORE could observe the expected Hanle effect in corona with a HI Lyman-alpha polarimeter.

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

    Science.gov (United States)

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

    2013-01-01

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

  11. Disinfection of hepatitis A virus and MS-2 coliphage in water by ultraviolet irradiation: comparison of UV-susceptibilty

    Energy Technology Data Exchange (ETDEWEB)

    Wiedenmann, A; Fischer, B; Straub, U; Wang, C -H; Flehmig, B [Tuebingen Univ. (Germany). Hygiene-Inst.; Schoenen, D [Bonn Univ. (Germany). Hygiene-Inst.

    1993-01-01

    Ultraviolet irradiation is gaining importance as a disinfection procedure for drinking water and in waste water treatment. Since water is one of the main transmission routes of hepatitis A virus the susceptibility of Hepatitis A Virus (HAV) to UV rays is of special interest. MS-2 coliphage resembles HAV in size and structure, is easy to handle, and might therefore serve as indicator organism for the assessment of water quality and for evaluating the quality of water treatment processes. Hepatitis A virus and MS-2 coliphage were suspended in 0.9% sodium chloride solution and were irradiated in a 20-ml quartz cuvette at 254 nm. For a reduction rate of four log units a three times higher UV dose was required with MS-2 than with HAV. (author).

  12. Disinfection of hepatitis A virus and MS-2 coliphage in water by ultraviolet irradiation: comparison of UV-susceptibilty

    International Nuclear Information System (INIS)

    Wiedenmann, A.; Fischer, B.; Straub, U.; Wang, C.-H.; Flehmig, B.; Schoenen, D.

    1993-01-01

    Ultraviolet irradiation is gaining importance as a disinfection procedure for drinking water and in waste water treatment. Since water is one of the main transmission routes of hepatitis A virus the susceptibility of Hepatitis A Virus (HAV) to UV rays is of special interest. MS-2 coliphage resembles HAV in size and structure, is easy to handle, and might therefore serve as indicator organism for the assessment of water quality and for evaluating the quality of water treatment processes. Hepatitis A virus and MS-2 coliphage were suspended in 0.9% sodium chloride solution and were irradiated in a 20-ml quartz cuvette at 254 nm. For a reduction rate of four log units a three times higher UV dose was required with MS-2 than with HAV. (author)

  13. Disinfection of hepatitis A virus and MS-2 coliphage in water by ultraviolet irradiation: comparison of UV-susceptibility

    Energy Technology Data Exchange (ETDEWEB)

    Widenmann, A.; Fischer, B.; Straub, U.; Wang, C. H.; Flehmig, B.; Schoenen, D. [Abteilung für Allgemeine Hygiene und Umwelthygiene, Hygiene-Institut der Universitat Tubingen, D-7400 Tubingen (Germany)

    1993-07-01

    Ultraviolet irradiation is gaining importance as a disinfection procedure for drinking water and in waste water treatment. Since water is one of the main transmission routes of hepatitis A virus the susceptibility of HAV to UV rays is of special interest. MS-2 coliphage resembles HAV in size and structure, is easy to handle, and might tlierefore serve as indicator organism for the assessment of water quality and for evaluating the quality of water treatment processes. Hepatitis A virus and MS-2 coliphage were suspended in 0.9% sodium chloride solution and were irradiated in a 20-ml quarz cuvette at 254 nm. For a reduction rate of four log units a three times lighter UV dose was required with MS-2 than with HAV.

  14. Ultraviolet Imaging with Low Cost Smartphone Sensors: Development and Application of a Raspberry Pi-Based UV Camera

    Directory of Open Access Journals (Sweden)

    Thomas C. Wilkes

    2016-10-01

    Full Text Available Here, we report, for what we believe to be the first time, on the modification of a low cost sensor, designed for the smartphone camera market, to develop an ultraviolet (UV camera system. This was achieved via adaptation of Raspberry Pi cameras, which are based on back-illuminated complementary metal-oxide semiconductor (CMOS sensors, and we demonstrated the utility of these devices for applications at wavelengths as low as 310 nm, by remotely sensing power station smokestack emissions in this spectral region. Given the very low cost of these units, ≈ USD 25, they are suitable for widespread proliferation in a variety of UV imaging applications, e.g., in atmospheric science, volcanology, forensics and surface smoothness measurements.

  15. UV-C 13-50 ultraviolet irradiation unit for surface sterilization

    International Nuclear Information System (INIS)

    Bachmann, R.

    1979-01-01

    Brown Boveri have developed new watertight ultraviolet irradiation units for surface sterilization. Their main application is in packing techniques in the foodstuffs and pharmaceutical industries. This article describes the construction, germicidal effect, and applications of these irradiation units. (Auth.)

  16. The effect of ultraviolet (UV)-B radiation on primary producers

    International Nuclear Information System (INIS)

    Germ, M.

    2003-01-01

    Ozone layer in stratosphere is thinning and consequently UV-B radiation on the Earth surface is increasing. Although there is a small portion of UV-B radiation in the solar radiation, it has strong influence on organisms. Targets of UV-B radiation and protective mechanisms in primary producers are described. In the framework of the international project we studied the effect of UV-B radiation on blue-greens, algae, mosses, lichens and vascular plants on the National Institute of Biology

  17. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-30

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

  19. 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.

  20. Innovative Approach to Validation of Ultraviolet (UV) Reactors for Disinfection in Drinking Water Systems

    Science.gov (United States)

    Slide presentation at Conference: ASCE 7th Civil Engineering Conference in the Asian Region. USEPA in partnership with the Cadmus Group, Carollo Engineers, and other State & Industry collaborators, are evaluating new approaches for validating UV reactors to meet groundwater & sur...

  1. 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)

  2. Monitoring ultraviolet (UV) radiation inactivation of Cronobacter sakazakii in dry infant formula using Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Liu, Qian; Lu, Xiaonan; Swanson, Barry G; Rasco, Barbara A; Kang, Dong-Hyun

    2012-01-01

    Cronobacter sakazakii is an opportunistic pathogen associated with dry infant formula presenting a high risk to low birth weight neonates. The inactivation of C. sakazakii in dry infant formula by ultraviolet (UV) radiation alone and combined with hot water treatment at temperatures of 55, 60, and 65 °C were applied in this study. UV radiation with doses in a range from 12.1 ± 0.30 kJ/m² to 72.8 ± 1.83 kJ/m² at room temperature demonstrated significant inactivation of C. sakazakii in dry infant formula (P radiation combining 60 °C hot water treatment increased inactivation of C. sakazakii cells significantly (P radiation on C. sakazakii inactivation kinetics (D value) were not observed in infant formula reconstituted in 55 and 65 °C water (P > 0.05). The inactivation mechanism was investigated using vibrational spectroscopy. Infrared spectroscopy detected significant stretching mode changes of macromolecules on the basis of spectral features, such as DNA, proteins, and lipids. Minor changes on cell membrane composition of C. sakazakii under UV radiation could be accurately and correctly monitored by infrared spectroscopy coupled with 2nd derivative transformation and principal component analysis. © 2011 Institute of Food Technologists®

  3. 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.

  4. Visible-blind ultraviolet photodiode fabricated by UV oxidation of metallic zinc on p-Si

    International Nuclear Information System (INIS)

    Zhang, Dongyuan; Uchida, Kazuo; Nozaki, Shinji

    2015-01-01

    A UV photodiode fabricated by the UV oxidation of a metallic zinc thin film on p-Si has manifested unique photoresponse characteristics. The electron concentration found by the Hall measurement was 3 × 10 16  cm −3 , and such a low electron concentration resulted in a low visible photoluminescence. UV illumination enhances the oxidation at low temperatures and decreases the concentration of the oxygen vacancies. The I-V characteristic showed a good rectification with a four-order magnitude difference in the forward and reverse currents at 2 V, and its linear and frequency independent C −2 –V characteristic confirmed an abrupt pn junction. The photoresponse showed a visible blindness with a responsivity ratio of UV and visible light as high as 100. Such a visible-blind photoresponse was attributed to the optimum thickness of the SiO 2 formed on the Si surface during the UV oxidation at 400 °C. A lower potential barrier to holes at the ZnO/SiO 2 interface facilitates Fowler-Nordheim tunneling of the photo-generated holes during the UV illumination, while a higher potential barrier to electrons efficiently blocks transport of the photo-generated electrons to the ZnO during the visible light illumination. The presence of oxide resulted in a slow photoresponse to the turn-on and off of the UV light. A detailed analysis is presented to understand how the photo-generated carriers contribute step by step to the photocurrent. In addition to the slow photoresponse associated with the SiO 2 interfacial layer, the decay of the photocurrent was found extremely slow after turn-off of the UV light. Such a slow decay of the photocurrent is referred to as a persistent photoconductivity, which is caused by metastable deep levels. It is hypothesized that Zn vacancies form such a deep level, and that the photo-generated electrons need to overcome a thermal-energy barrier for capture. The ZnO film by the UV oxidation at 400 °C was found to be rich in oxygen and

  5. Visible-blind ultraviolet photodiode fabricated by UV oxidation of metallic zinc on p-Si

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongyuan; Uchida, Kazuo; Nozaki, Shinji, E-mail: nozaki@ee.uec.ac.jp [Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu-shi, Tokyo 182-8585 (Japan)

    2015-09-07

    A UV photodiode fabricated by the UV oxidation of a metallic zinc thin film on p-Si has manifested unique photoresponse characteristics. The electron concentration found by the Hall measurement was 3 × 10{sup 16 }cm{sup −3}, and such a low electron concentration resulted in a low visible photoluminescence. UV illumination enhances the oxidation at low temperatures and decreases the concentration of the oxygen vacancies. The I-V characteristic showed a good rectification with a four-order magnitude difference in the forward and reverse currents at 2 V, and its linear and frequency independent C{sup −2}–V characteristic confirmed an abrupt pn junction. The photoresponse showed a visible blindness with a responsivity ratio of UV and visible light as high as 100. Such a visible-blind photoresponse was attributed to the optimum thickness of the SiO{sub 2} formed on the Si surface during the UV oxidation at 400 °C. A lower potential barrier to holes at the ZnO/SiO{sub 2} interface facilitates Fowler-Nordheim tunneling of the photo-generated holes during the UV illumination, while a higher potential barrier to electrons efficiently blocks transport of the photo-generated electrons to the ZnO during the visible light illumination. The presence of oxide resulted in a slow photoresponse to the turn-on and off of the UV light. A detailed analysis is presented to understand how the photo-generated carriers contribute step by step to the photocurrent. In addition to the slow photoresponse associated with the SiO{sub 2} interfacial layer, the decay of the photocurrent was found extremely slow after turn-off of the UV light. Such a slow decay of the photocurrent is referred to as a persistent photoconductivity, which is caused by metastable deep levels. It is hypothesized that Zn vacancies form such a deep level, and that the photo-generated electrons need to overcome a thermal-energy barrier for capture. The ZnO film by the UV oxidation at 400 °C was found

  6. 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

  7. Innovative Approach to Validation of Ultraviolet (UV) Reactors for Disinfection in Drinking Water Systems - presentation

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens found in source waters with the potential as stand-alone treatment or in combination with other disinfectants. For surface and groundwater sourced drinking water applications, the U.S. Environmental...

  8. Immunologic effects of whole body ultraviolet (uv) irradiation. II. Defect in splenic adherent cell antigen presentation for stimulation of T cell proliferation

    International Nuclear Information System (INIS)

    Letvin, N.L.; Fox, I.J.; Greene, M.I.; Benacerraf, B.; Germain, R.N.

    1980-01-01

    Ultraviolet (uv) irradiation has been shown to alter many parameters of the immunologic reactivity of mice. The altered responsiveness of uv-irradiated mice, as measured by delayed-type hypersensitivity (DTH) and primary in vitro plaque-forming cell (PFC) responses to T-dependent antigens, has recently been correlated with a functional defect in the splenic adherent cell population of these animals. The present studies describe a model of this altered responsiveness, which allows further clarification of the effects of external uv irradiation on the splenic antigen-presenting cell (APC) in its interactions with T cells

  9. General Astrophysics Science Enabled by the HabEx Ultraviolet Spectrograph (UVS)

    Science.gov (United States)

    Scowen, Paul; Clarke, John; Gaudi, B. Scott; Kiessling, Alina; Martin, Stefan; Somerville, Rachel; Stern, Daniel; HabEx Science and Technology Definition Team

    2018-01-01

    The Habitable Exoplanet Imaging Mission (HabEx) is one of the four large mission concepts being studied by NASA as input to the upcoming 2020 Decadal Survey. The mission implements two world-class General Astrophysics instruments as part of its complement of instrumentation to enable compelling science using the 4m aperture. The Ultraviolet Spectrograph has been designed to address cutting edge far ultraviolet (FUV) science that has not been possible with the Hubble Space Telescope, and to open up a wide range of capabilities that will advance astrophysics as we look into the 2030s. Our poster discusses some of those science drivers and possible applications, which range from Solar System science, to nearby and more distant studies of star formation, to studies of the circumgalactic and intergalactic mediums where the ecology of mass and energy transfer are vital to understanding stellar and galactic evolution. We discuss the performance features of the instrument that include a large 3’x3’ field of view for multi-object spectroscopy, and some 20 grating modes for a variety of spectral resolution and coverage.

  10. Ground-based photo monitoring

    Science.gov (United States)

    Frederick C. Hall

    2000-01-01

    Ground-based photo monitoring is repeat photography using ground-based cameras to document change in vegetation or soil. Assume those installing the photo location will not be the ones re-photographing it. This requires a protocol that includes: (1) a map to locate the monitoring area, (2) another map diagramming the photographic layout, (3) type and make of film such...

  11. Images in the rocket ultraviolet - UV fluxes of M31 globular clusters

    International Nuclear Information System (INIS)

    Bohlin, R.C.; Cornett, R.H.; Hill, J.K.; Hill, R.S.; Stecher, T.P.

    1988-01-01

    Images obtained by a rocket-borne UV imaging telescope are used here to determine near-UV fluxes for 17 sources in M31 that are optical globular-cluster candidates and for the bright open cluster vdB0 in M31. Far-UV fluxes or flux limits are determined for the same clusters. The m(NUV)-V colors for M31 clusters are similar to those of Galactic clusters, except for the high-metallicity M31 cluster Bo 171. Four of the detected clusters have optical, m(NUV) - V, and m(FUV) - V colors indicating ages of about 100 million years. These four clusters are probably similar to the so-called 'blue globular' clusters of the LMC. The existence of young LMC-type blue globulars and the possible existence of middle-aged metal-rich globulars may indicate that M31 has continued to form globular clusters throughout its life. 39 references

  12. Cell-cycle kinetics and ultraviolet light survival in UV-1, a Chinese hamster ovary cell mutant defective in post-replication recovery

    International Nuclear Information System (INIS)

    Collins, A.

    1982-01-01

    UV-I, an ultraviolet-sensitive mutant of CHO-KI, is abnormally slow to recover from the inhibition of DNA synthesis caused by u.v. irradiation. When synchronized UV-I cells are irradiated in G 1 , their movement into S phase is unaltered, but thymidine incorporation is depressed. When irradiated in S phase, again incorporation is more depressed, and S phase suffers a greater delay in UV-I than in the parent cell. UV-I and its parent have similar capacities for excision repair of u.v.-induced damage inflicted in G 1 , and so enter S phase with similar amounts of unrepaired damage. The single-cell survival was measured after irradiation at different points in the cell cycle. The mutant and parent cells have similar values of D 0 (mean lethal dose) except in mitosis, when the parent cell shows markedly greater resistance to u.v. irradiation. Dsub(q) (quasi-threshold dose) is fairly constant for the parent cell, but in UV-I it falls to a minimum in S phase. The responses of UV-I to u.v. irradiation are generally consistent with its known defect in post-replication recovery, i.e. the ability to join up the abnormally small DNA fragments synthesized on a u.v.-damaged template. (author)

  13. GALEX FAR-ULTRAVIOLET COLOR SELECTION OF UV-BRIGHT HIGH-REDSHIFT QUASARS

    International Nuclear Information System (INIS)

    Worseck, Gabor; Prochaska, J. Xavier

    2011-01-01

    We study the small population of high-redshift (z em >2.7) quasars detected by the Galaxy Evolution Explorer(GALEX), whose far-UV emission is not extinguished by intervening H I Lyman limit systems. These quasars are of particular importance to detect intergalactic He II absorption along their sight lines. We correlate almost all verified z em >2.7 quasars to the GALEX GR4 source catalog covering ∼ 25,000 deg 2 , yielding 304 sources detected at signal-to-noise ratio (S/N) >3. However, ∼50% of these are only detected in the GALEX NUV band, signaling the truncation of the FUV flux by low-redshift optically thick Lyman limit systems. We exploit the GALEX UV color m FUV - m NUV to cull the most promising targets for follow-up studies, with blue (red) GALEX colors indicating transparent (opaque) sight lines. Extensive Monte Carlo simulations indicate an He II detection rate of ∼60% for quasars with m FUV - m NUV ∼ em ∼ 3 to be most promising for Hubble Space Telescope follow-up, with an additional 114 quasars if we consider S/N >2 detections in the FUV. Combining the statistical properties of H I absorbers with the Sloan Digital Sky Survey (SDSS) quasar luminosity function, we predict a large all-sky population of ∼200 quasars with z em >2.7 and i ∼ 304 em ∼ em ∼ em ∼< 3.5 quasars have likely underestimated their space density by selecting intergalactic medium sight lines with an excess of strong H I absorbers.

  14. Robust Ultraviolet-Visible (UV-Vis) Partial Least-Squares (PLS) Models for Tannin Quantification in Red Wine.

    Science.gov (United States)

    Aleixandre-Tudo, José Luis; Nieuwoudt, Helené; Aleixandre, José Luis; Du Toit, Wessel J

    2015-02-04

    The validation of ultraviolet-visible (UV-vis) spectroscopy combined with partial least-squares (PLS) regression to quantify red wine tannins is reported. The methylcellulose precipitable (MCP) tannin assay and the bovine serum albumin (BSA) tannin assay were used as reference methods. To take the high variability of wine tannins into account when the calibration models were built, a diverse data set was collected from samples of South African red wines that consisted of 18 different cultivars, from regions spanning the wine grape-growing areas of South Africa with their various sites, climates, and soils, ranging in vintage from 2000 to 2012. A total of 240 wine samples were analyzed, and these were divided into a calibration set (n = 120) and a validation set (n = 120) to evaluate the predictive ability of the models. To test the robustness of the PLS calibration models, the predictive ability of the classifying variables cultivar, vintage year, and experimental versus commercial wines was also tested. In general, the statistics obtained when BSA was used as a reference method were slightly better than those obtained with MCP. Despite this, the MCP tannin assay should also be considered as a valid reference method for developing PLS calibrations. The best calibration statistics for the prediction of new samples were coefficient of correlation (R 2 val) = 0.89, root mean standard error of prediction (RMSEP) = 0.16, and residual predictive deviation (RPD) = 3.49 for MCP and R 2 val = 0.93, RMSEP = 0.08, and RPD = 4.07 for BSA, when only the UV region (260-310 nm) was selected, which also led to a faster analysis time. In addition, a difference in the results obtained when the predictive ability of the classifying variables vintage, cultivar, or commercial versus experimental wines was studied suggests that tannin composition is highly affected by many factors. This study also discusses the correlations in tannin values between the methylcellulose and protein

  15. Effect and mechanism of a High Gradient Magnetic Separation (HGMS) and Ultraviolet (UV) composite process on the inactivation of microbes in ballast water

    International Nuclear Information System (INIS)

    Ren, Zhijun; Zhang, Lin; Shi, Yue; Leng, Xiaodong; Shao, Jingchao

    2016-01-01

    The patented technology of a High Gradient Magnetic Separation (HGMS)-Ultraviolet (UV) composite process was used to treat ballast water. Staphylococcus aureus (S. aureus) was selected as the reference bacteria. After treatment by the HGMS-UV process, the concentration of S. aureus on the log 10 scale was lower than 2 at different flow rates, S. aureus suffered the most serious damage, and K + leakage of the bacteria was 1.73 mg/L higher than separate 60 min UV irradiation (1.17 mg/L) and HGMS (0.12 mg/L) processes. These results demonstrated that the HGMS-UV composite process was an effective approach to treat ballast water. Further, the HGMS process had synergistic action on the subsequent UV irradiation process and accelerated cell membrane damage. Meanwhile, the results of superoxide dismutase (SOD) activities of bacteria and DNA band analyses indicated that the inactivation mechanisms were different for HGMS and UV irradiation. - Highlights: •The HGMS process had synergistic action on the subsequent UV irradiation process. •HGMS directly influenced the active center of a metal enzyme and did not cause damage to DNA. •UV irradiation was found to depend on the production of free radicals to affect the bacterial DNA and enzyme activity.

  16. THE UV CONTINUUM OF z > 1 STAR-FORMING GALAXIES IN THE HUBBLE ULTRAVIOLET ULTRADEEP FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Kurczynski, Peter; Gawiser, Eric [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Rafelski, Marc [NASA Postdoctoral Program Fellow, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Teplitz, Harry I. [Infrared Processing and Analysis Center, MS 100-22, Caltech, Pasadena, CA 91125 (United States); Acquaviva, Viviana [New York City College of Technology, Brooklyn, NY 11201 (United States); Brown, Thomas M.; Coe, Dan; Grogin, Norman A.; Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); De Mello, Duilia F. [Laboratory for Observational Cosmology, Astrophysics Science Division, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finkelstein, Steven L. [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States); Lee, Kyoung-soo [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Scarlata, Claudia [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Siana, Brian D. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)

    2014-09-20

    We estimate the UV continuum slope, β, for 923 galaxies in the range 1 < z < 8 in the Hubble Ultradeep Field (HUDF). These data include 460 galaxies at 1 < z < 2 down to an absolute magnitude M{sub UV}=−14(∼0.006 L{sub z=1}{sup ∗};0.02 L{sub z=0}{sup ∗}), comparable to dwarf galaxies in the local universe. We combine deep HST/UVIS photometry in F225W, F275W, F336W wavebands (UVUDF) with recent data from HST/WFC3/IR (HUDF12). Galaxies in the range 1 < z < 2 are significantly bluer than local dwarf galaxies. We find their mean (median) values <β > = – 1.382(– 1.830) ± 0.002 (random) ± 0.1 (systematic). We find comparable scatter in β (standard deviation = 0.43) to local dwarf galaxies and 30% larger scatter than z > 2 galaxies. We study the trends of β with redshift and absolute magnitude for binned sub-samples and find a modest color-magnitude relation, dβ/dM = –0.11 ± 0.01, and no evolution in dβ/dM with redshift. A modest increase in dust reddening with redshift and luminosity, ΔE(B – V) ∼ 0.1, and a comparable increase in the dispersion of dust reddening at z < 2, appears likely to explain the observed trends. At z > 2, we find trends that are consistent with previous works; combining our data with the literature in the range 1 < z < 8, we find a color evolution with redshift, dβ/dz = –0.09 ± 0.01 for low luminosity (0.05 L{sub z=3}{sup ∗}), and dβ/dz = –0.06 ± 0.01 for medium luminosity (0.25 L{sub z=3}{sup ∗}) galaxies.

  17. Survey Efficiency of Ultraviolet and Zinc Oxide Process (UV/ZnO for Removal of Diazinon Pesticide from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Mohammad Hadi Dehghani

    2015-03-01

    Full Text Available The presence of persistent organic pollutants and toxics (e.g., pesticides in ground, surface, and drinking water resources combined with the inability of conventional treatment methods to remove these pollutants have led to the development of advanced oxidation processes. Nowadays, nanophotocatalyst processes are considered as clean and environmentally-friendly treatment methods that can be extensively used for removing contaminants. The objective of the present study was to determine the efficiency of the ultraviolet and zinc oxide (UV/ZnO process in the removal of diazinon pesticide from aqueous solutions. For the purposes of this study, samples were adjusted in a batch reactor at five different detention times. The pH levels used were 3, 7, and 9. Irradiation was performed using a 125 W medium-pressure mercury lamp. The diazinon concentrations of the samples were 100 and 500 µg/L and the concentrations of zinc oxide nanoparticles were 50, 100, and 150 mg/L. The highest degradation efficiency was observed at pH 7 (mean = 80.92 30.3, while the lowest was observed for pH 3 (mean 67.11 24.49. Results showed that the optimal concentration of nanoparticles (6-12 nm was 100 mg L-1.

  18. The use of epoxidised palm oil products (EPOP) for the synthesis of radiation curable resins. II. Ultraviolet (UV) curing of epoxidised RBD palm oil acrylate (EPOLA)

    International Nuclear Information System (INIS)

    Mohd Hilmi bin Mahmood; Hussin bin Mohd Nor; Hamirin bin Kifli; Masni bin Abdul Ragman; Azman bin Rafei

    1991-01-01

    Epoxidised RBD palm olein acrylate (EPOLA) and polyurethane acrylate (PUA) prepared at UTN laboratory were used as base polymers or oligomers in the formulations of ultraviolet (UV) curable resins. Mono-, di- and trifunctional monomers were utilized both as crosslinkers as well as for diluents. Curing was done by means of 20 cm wide IST UV machine with the conditions of 8A current and 4m/min conveyor speed. The properties of the cured films were investigated by using pencil hardness tester and gel content analysis

  19. Ultraviolet (UV and Hydrogen Peroxide Activate Ceramide-ER Stress-AMPK Signaling Axis to Promote Retinal Pigment Epithelium (RPE Cell Apoptosis

    Directory of Open Access Journals (Sweden)

    Jin Yao

    2013-05-01

    Full Text Available Ultraviolet (UV radiation and reactive oxygen species (ROS impair the physiological functions of retinal pigment epithelium (RPE cells by inducing cell apoptosis, which is the main cause of age-related macular degeneration (AMD. The mechanism by which UV/ROS induces RPE cell death is not fully addressed. Here, we observed the activation of a ceramide-endoplasmic reticulum (ER stress-AMP activated protein kinase (AMPK signaling axis in UV and hydrogen peroxide (H2O2-treated RPE cells. UV and H2O2 induced an early ceramide production, profound ER stress and AMPK activation. Pharmacological inhibitors against ER stress (salubrinal, ceramide production (fumonisin B1 and AMPK activation (compound C suppressed UV- and H2O2-induced RPE cell apoptosis. Conversely, cell permeable short-chain C6 ceramide and AMPK activator AICAR (5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide mimicked UV and H2O2’s effects and promoted RPE cell apoptosis. Together, these results suggest that UV/H2O2 activates the ceramide-ER stress-AMPK signaling axis to promote RPE cell apoptosis.

  20. Effects of enhanced ultraviolet-B radiation, water deficit, and their combination on UV-absorbing compounds and osmotic adjustment substances in two different moss species.

    Science.gov (United States)

    Hui, Rong; Zhao, Ruiming; Song, Guang; Li, Yixuan; Zhao, Yang; Wang, Yanli

    2018-05-01

    A simulation experiment was conducted to explore the influence of enhanced ultraviolet-B (UV-B) radiation, water deficit, and their combination on UV-absorbing compounds and osmotic adjustment substances of mosses Bryum argenteum and Didymodon vinealis isolated from biological soil crusts (BSCs) growing in a revegetated area of the Tengger Desert, China. Four levels of UV-B radiation and two gradients of water regime were employed. Compared with their controls, amounts of total flavonoids, chlorophyll, carotenoids, soluble sugars, and soluble proteins significantly decreased (p argenteum, D. vinealis was more resistant to enhanced UV-B and water deficit singly and in combination. These results suggest that the damage of enhanced UV-B on both species might be alleviated by water deficit. This alleviation is important for understanding the response of BSCs to UV-B radiation in future global climate change. This also provides novel insights into assessment damages of UV-B to BSC stability in arid and semiarid regions.

  1. 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)

  2. A model investigation of annual surface ultraviolet radiation in Iran

    International Nuclear Information System (INIS)

    Sabziparvar, A.-A.

    2003-01-01

    In recent years, there has been some concern regarding solar ultraviolet (UV) radiation received at the earth,s surface because of its biological hazards affecting living organisms. Although the geographical distribution of ground-based UV network is relatively good in some continents,but over Asia, the number of UV instruments are not sufficient for meteorological and biological purposes. Iran, as an Asian country, is also suffering from the lack of UV monitoring network with the exception of one ground-based UV spectrophotometer site (Brower III) at Esfahan. Using a complex radiative transfer model and various meteorological data (for 8 years) such as total column ozone, cloudiness, surface albedo, surface air pressure, relative humidity, visibility and daily total solar radiation (TSR), the geographical distribution of annual integrated biological surface UV irradiances such as UVB, erythema and cataracts are calculated. The comparison is made for cloud-free and all-sky conditions for eight selected cities distributed from the southern tip of the country (25 N-60 E) to the northern border (39 N-48 E). It is shown that the difference between the annual UV at south and north in all-sky condition is larger than the differences in cloud-free condition. The ratio of some biological UV irradiances at southern cities to the same component at northern cities shows a factor of two and more which is quite significant. The possible reasons which might cause such differences are discussed

  3. Ultraviolet-Visible (UV-Vis) Microspectroscopic System Designed for the In Situ Characterization of the Dehydrogenation Reaction Over Platinum Supported Catalytic Microchannel Reactor.

    Science.gov (United States)

    Suarnaba, Emee Grace Tabares; Lee, Yi Fuan; Yamada, Hiroshi; Tagawa, Tomohiko

    2016-11-01

    An ultraviolet visible (UV-Vis) microspectroscopic system was designed for the in situ characterization of the activity of the silica supported platinum (Pt) catalyst toward the dehydrogenation of 1-methyl-1,4-cyclohexadiene carried out in a custom-designed catalytic microreactor cell. The in situ catalytic microreactor cell (ICMC) with inlet/outlet ports was prepared using quartz cover as the optical window to facilitate UV-Vis observation. A fabricated thermometric stage was adapted to the UV-Vis microspectrophotometer to control the reaction temperature inside the ICMC. The spectra were collected by focusing the UV-Vis beam on a 30 × 30 µm area at the center of ICMC. At 393 K, the sequential measurement of the spectra recorded during the reaction exhibited a broad absorption peak with maximum absorbance at 260 nm that is characteristic for gaseous toluene. This result indicates that the silica supported Pt catalyst is active towards the dehydrogenation of 1-methyl-1,4-cyclohexadiene at the given experimental conditions. The onset of coke formation was also detected based on the appearance of absorption bands at 300 nm. The UV-Vis microspectroscopic system developed can be used further in studying the mechanism of the dehydrogenation reaction. © The Author(s) 2016.

  4. Chromosomal analysis in mouse eggs fertilized in vitro with sperm exposed to ultraviolet light (UV) and methyl and ethyl methanesulfonate (MMS and EMS)

    International Nuclear Information System (INIS)

    Matsuda, Y.; Tobari, I.

    1988-01-01

    Chromosome aberrations were analyzed at the first-cleavage metaphase of mouse eggs fertilized in vitro with sperm exposed to ultraviolet light (UV) as well as to methyl and ethyl methanesulfonate (MMS and EMS). The frequencies of chromosome aberrations markedly increased with dose of UV as well as with concentration of MMS and EMS. In the UV-irradiation group, the frequency of chromosome-type aberrations was much higher than that of chromatid-type aberrations. About 90% of chromosome aberrations observed in the eggs following MMS and EMS treatment to sperm were chromosome type in which the frequency of chromosome fragments was the highest. The effects of UV on the induction of chromosome aberrations were clearly potentiated by post-treatment incubation of fertilized eggs in the presence of Ara-C or caffeine, but the effects of MMS and EMS were not pronounced by post-treatment of Ara-C or caffeine. The results indicate a possibility that UV damage induced in mouse sperm DNA is reparable in the eggs during the period between the entry of sperm into the egg cytoplasm and the first-cleavage metaphase. 35 refs.; 5 figs.; 4 tabs

  5. Effects of ultraviolet irradiation on the cell cycle in normal and UV-sensitive cell lines with reference to the nature of the defect in xeroderma pigmentosum variant

    International Nuclear Information System (INIS)

    Imray, P.; Mangan, T.; Saul, A.; Kidson, C.

    1983-01-01

    Analysis of the distribution of cells through the phases of the cell cycle by DNA flow cytofluorimetry has been utilized to investigate the effects of ultraviolet (UV) irradiation on cell-cycle progression in normal and UV-sensitive lymphoblastoid cell lines. In time-course studies only slight perturbation of DNA distribution was seen in normal cells, or UV-sensitive familial melanoma (FM) lines in the 48 h following irradiation. Xeroderma pigmentosum (XPA) excision-deficient cells showed a large increase in the proportion of cells in S phase 16-40 h post-irradiation. XP variant (XPV) cells were blocked in G 1 and S phases with the complete absence of cells with G 2 DNA content 16-28 h after irradiation. By 48 h post-irradiation the DNA distribution of XPA and XPV cells had returned to that of an unirradiated control. When colcemid was added to the cultures immediately after irradiation to prevent mitotic cells dividing and re-entering the cell cycle, progression through the first cycle after irradiation was followed. UV irradiation did not affect the rate of movement of cells out of G 1 into S phase in normal, FM or XPA cells. The proportion of cells in S phase was increased in UV-irradiated cultures in these cell types and the number of cells entering the G 2 +M compartment was reduced. (orig./AJ)

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

    International Nuclear Information System (INIS)

    Correia, C.M.; Torres-Pereira, M.S.; Torres-Pereira, J.M.G.

    1999-01-01

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

  7. Ultraviolet-B (UV-B) radiation as an elicitor of flavonoid production in callus cultures of jatropha (Jatropha curcas L.)

    International Nuclear Information System (INIS)

    Alvero-Bascos, E.M.; Ungson, L.B.

    2012-01-01

    Callus cultures of jatropha (Jatropha curcas L.) grown in Murashige and Skoog's (MS) medium supplemented with naphthalene-acetic acid (NAA, 20 microM) and 6-furfurylaminopurine (kinetin, 20 microM) were exposed to ultraviolet-B (UV-B) radiation to investigate its potential as an abiotic elicitor of flavonoid production. Prior to irradiation, the levels of the flavonoids, apigenin, vitexin and isovitexin in the leaf and callus extracts were determined through high performance liquid chromatography (HPLC). Results showed that vitexin and isovitexin were the dominant flavonoids in the leaves while only apigenin was detected in the calli, suggesting a correlation between the degree of differentiation and biosynthesis of flavonoids in plant tissues. Irradiation of callus cultures for 7 d using two UV-B doses (12.6 and 25.3 kJ/sq m) induced synthesis of all three flavonoids (up to 780 micro g/g dw increase) to levels similar to or higher than those found in whole leaves. The combined levels of the three flavonoids in the cultures treated with the higher UV-B dose were 20-fold higher than the control and were comparable to concentrations found in leaves while a 10-fold increase in combined flavonoid levels was observed in calli irradiated with the lower UV-B dose. Furthermore, random amplified polymorphic DNA (RAPD) analyses of DNA extracts from the leaves and calli revealed that UV-B irradiation enhanced flavonoid synthesis without altering DNA sequence. These results further support the supposed involvement of UV-B in the transcriptional regulation of the expression of flavonoid biosysnthetic genes. Overall, the findings showed that elicitation through UV-B irradiation is an effective strategy to induce flavonoid production in dedifferentiated J. curcas cultures that have lost their capacity to produce the flavonoids normally synthesized in intact organs. (author)

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

    International Nuclear Information System (INIS)

    Tosserams, M.; Rozema, J.

    1995-01-01

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

  9. 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

  10. 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...

  11. Acute Toxicity and Ecological Risk Assessment of Benzophenone-3 (BP-3 and Benzophenone-4 (BP-4 in Ultraviolet (UV-Filters

    Directory of Open Access Journals (Sweden)

    Yang Du

    2017-11-01

    Full Text Available Ultraviolet (UV-absorbing chemicals (UV filters are used in personal care products for the protection of human skin and hair from damage by UV radiation. Although these substances are released into the environment in the production and consumption processes, little is known about their ecotoxicology effects. The acute toxicity and potential ecological risk of UV filters benzophenone-3 (BP-3 and benzophenone-4 (BP-4 on Chlorella vulgaris, Daphnia magna, and Brachydanio rerio were analyzed in the present study. The EC50 values (96 h of BP-3 and BP-4 on C. vulgaris were 2.98 and 201.00 mg/L, respectively. The 48 h-LC50 of BP-3 and BP-4 on D. magna were 1.09 and 47.47 mg/L, respectively. The 96 h-LC50 of BP-3 and BP-4 on B. rerio were 3.89 and 633.00 mg/L, respectively. The toxicity of a mixture of BP-3 and BP-4 on C. vulgaris, D. magna, and B. rerio all showed antagonistic effects. The induced predicted no-effect concentrations of BP-3 and BP-4 by the assessment factor method were 1.80 × 10−3 and 0.47 mg/L, respectively, by assessment factor (AF method, which were both lower than the concentrations detected in the environment at present, verifying that BP-3 and BP-4 remain low-risk chemicals to the aquatic ecosystem.

  12. Immunogenicity of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) following inactivation by betapropiolactone (BPL) and ultraviolet (UV) light

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, T.M.; Studdert, M.J.; Blackney, M.H. (Melbourne Univ., Parkville (Australia). School of Veterinary Science)

    1982-12-01

    Some kinetic data on the inactivation of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) by betapropiolactone (BPL) and ultraviolet (UV) irradiation are reported. 0.25% BPL at 37/sup 0/C for 1 h reduced the titre of EHV1 by > 10sup(3.4) and of ERhV1 by > 10sup(4.1) TCID/sub 50//ml. UV irradiation (334 ..mu..W/cm/sup 2/) produced similar reductions in titre after 2 min. These data were used as a basis for inactivating EHV1 and ERhV1 by the combined action of BPL and UV irradiation. Viruses were exposed to 0.1% BPL for 1 h at 4/sup 0/C with constant stirring, followed by UV irradiation for 2 min, followed by incubation for 3 h at 37/sup 0/C. Inactivated EHV1 elicted secondary immune responses only in horses whereas ERhV1 produced primary immune responses in mice (including athymic nu/nu mice), rabbits and probably in horses.

  13. Immunogenicity of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) following inactivation by betapropiolactone (BPL) and ultraviolet (UV) light

    International Nuclear Information System (INIS)

    Campbell, T.M.; Studdert, M.J.; Blackney, M.H.

    1982-01-01

    Some kinetic data on the inactivation of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) by betapropiolactone (BPL) and ultraviolet (UV) irradiation are reported. 0.25% BPL at 37 0 C for 1 h reduced the titre of EHV1 by > 10sup(3.4) and of ERhV1 by > 10sup(4.1) TCID 50 /ml. UV irradiation (334 μW/cm 2 ) produced similar reductions in titre after 2 min. These data were used as a basis for inactivating EHV1 and ERhV1 by the combined action of BPL and UV irradiation. Viruses were exposed to 0.1% BPL for 1 h at 4 0 C with constant stirring, followed by UV irradiation for 2 min, followed by incubation for 3 h at 37 0 C. Inactivated EHV1 elicted secondary immune responses only in horses whereas ERhV1 produced primary immune responses in mice (including athymic nu/nu mice), rabbits and probably in horses. (Auth.)

  14. 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.

  15. Pre-oxidation of low-density polyethylene (LDPE) by ultraviolet light (UV) promotes enhanced degradation of LDPE in soil.

    Science.gov (United States)

    Tribedi, Prosun; Dey, Samrat

    2017-11-09

    Polyethylene represents nearly 64% of all the synthetic plastics produced and are mainly used for domestic and industrial applications. Their extensive use poses a serious environmental threat because of their non-biodegradable nature. Among all the polyethylene remediation strategies, in situ bioremediation happens to be the safest and efficient one. In the current study, efforts had been given to compare the extent of LDPE degradation under UV-treated and UV-untreated conditions by soil microcosm. Landfill soil was collected and UV-treated and UV-untreated LDPE were added separately to the soil following incubation under similar conditions. Electron microscopic images as well as the weight loss and the tensile strength results clearly revealed that UV-treated LDPE showed better degradation than the non-treated ones in soil. To elucidate the mechanism of this enhanced biodegradation, the bond spectra of differentially treated LDPE were analyzed by FTIR. The results obtained from bond spectra studies revealed that UV treatment increases both carbonyl and terminal double-bond index of the LDPE, thereby making it highly susceptible for microbial degradation. Moreover, incubation of UV-treated LDPE with soil favors better adherence of metabolically active and significantly higher number of microorganisms on it. Taken together, all these results demonstrate the higher microbial association and their better metabolic potential to the UV-treated LDPE that lead to enhanced degradation of the LDPE by the soil microorganisms.

  16. Bystander effects in UV-induced genomic instability: Antioxidants inhibit delayed mutagenesis induced by ultraviolet A and B radiation

    Directory of Open Access Journals (Sweden)

    Dahle Jostein

    2005-01-01

    Full Text Available Abstract Background Genomic instability is characteristic of many types of human cancer. Recently, we reported that ultraviolet radiation induced elevated mutation rates and chromosomal instability for many cell generations after ultraviolet irradiation. The increased mutation rates of unstable cells may allow them to accumulate aberrations that subsequently lead to cancer. Ultraviolet A radiation, which primarily acts by oxidative stress, and ultraviolet B radiation, which initially acts by absorption in DNA and direct damage to DNA, both produced genomically unstable cell clones. In this study, we have determined the effect of antioxidants on induction of delayed mutations by ultraviolet radiation. Delayed mutations are indicative of genomic instability. Methods Delayed mutations in the hypoxanthine phosphoribosyl transferase (hprt gene were detected by incubating the cells in medium selectively killing hprt mutants for 8 days after irradiation, followed by a 5 day period in normal medium before determining mutation frequencies. Results The UVB-induced delayed hprt mutations were strongly inhibited by the antioxidants catalase, reduced glutathione and superoxide dismutase, while only reduced glutathione had a significant effect on UVA-induced delayed mutations. Treatment with antioxidants had only minor effects on early mutation frequenies, except that reduced glutathione decreased the UVB-induced early mutation frequency by 24 %. Incubation with reduced glutathione was shown to significantly increase the intracellular amount of reduced glutathione. Conclusion The strong effects of these antioxidants indicate that genomic instability, which is induced by the fundamentally different ultraviolet A and ultraviolet B radiation, is mediated by reactive oxygen species, including hydrogen peroxide and downstream products. However, cells take up neither catalase nor SOD, while incubation with glutathione resulted in increased intracellular levels of

  17. Factors affecting ultraviolet irradiation/hydrogen peroxide (UV/H2O2) degradation of mixed N-nitrosamines in water

    International Nuclear Information System (INIS)

    Zhou, Chao; Gao, Naiyun; Deng, Yang; Chu, Wenhai; Rong, Wenlei; Zhou, Shengdong

    2012-01-01

    Highlights: ► NAms with three-induced toxicity, as emerging DBPs, has caused a great public attention. ► No paper regards UV/H 2 O 2 oxidation of mixed NAms in an aquatic environment. ► The treatment effect is typically affected by a few factors in water. ► NPIP and NDPhA are the most readily and difficult to be degraded due to unique structure. ► All the NAms degradation exhibited a pseudo-first-order kinetics pattern. - Abstract: Disinfection by-products (DBPs) are a great challenge to our drinking water security. Particularly, nitrosamines (NAms), as emerging DBPs, are potently carcinogenic, mutagenic, and teratogenic, and have increasingly attained public attention. This study was to evaluate the performance of the NAms degradation by the ultraviolet (UV) irradiation (253.7 nm) in the presence of hydrogen peroxide (H 2 O 2 ). In the UV/H 2 O 2 system, hydroxyl radicals (OH·), a type of nonselective and powerful oxidant, was produced to attack the molecules of NAms. Factors affecting the treatment efficiency, including the H 2 O 2 dosage, initial NAms concentration, UV irradiation intensity, initial solution pH, and inorganic anions present in water, were evaluated. All the NAms degradation exhibited a pseudo-first-order kinetics pattern. Within 60 min, 0.1 mg/L of any NAms could be almost decomposed except NDPhA that required 120 min for complete removal, at 25 μmol/L H 2 O 2 and at initial pH 7. Results demonstrate that the UV/H 2 O 2 treatment is a viable option to control NAms in water.

  18. Effects of Relative Humidity and Spraying Medium on Ultraviolet (UV) Decontamination of Filters Loaded with Viral Aerosols

    Science.gov (United States)

    2012-02-01

    as can chloramines (F. J. Madeline, personal communication). The use of direct microwave irradiation to kill microorganisms through thermal and...transmission modes as a function of UV irradiation time in different nebulizer media. UV Disinfection of Filters August 2012 Volume 78 Number 16 aem.asm.org...at contact. The equation for evaporation time is the following (11): tevaporation time Rpdd 2 8DvM pdTd p T (2) where R is the ideal gas law

  19. Evaluation of an Innovative Approach to Validation of Ultraviolet (UV) Reactors for Disinfection in Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens found in source waters with the potential as stand-alone treatment or in combination with other disinfectants. For surface and groundwater sourced drinking water applications, the U.S. Environmental...

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

    Directory of Open Access Journals (Sweden)

    Uwe Feister

    2015-08-01

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

  1. Ultraviolet radiation and immunosuppression.

    LENUS (Irish Health Repository)

    Murphy, G M

    2009-11-01

    Ultraviolet (UV) radiation is a complete carcinogen. The effects of UV radiation are mediated via direct damage to cellular DNA in the skin and suppression of image surveillance mechanisms. In the context of organ transplantation, addiction of drugs which suppress the immune system add greatly to the carcinogenicity of UV radiation. This review considers the mechanisms of such effects.

  2. Ground-based observations of exoplanet atmospheres

    NARCIS (Netherlands)

    Mooij, Ernst Johan Walter de

    2011-01-01

    This thesis focuses on the properties of exoplanet atmospheres. The results for ground-based near-infrared secondary eclipse observations of three different exoplanets, TrES-3b, HAT-P-1b and WASP-33b, are presented which have been obtained with ground-based telescopes as part of the GROUSE project.

  3. Ultraviolet-Visible (UV-Vis) and Fluorescence Spectroscopic Investigation of the Interactions of Ionic Liquids and Catalase.

    Science.gov (United States)

    Dong, Xing; Fan, Yunchang; Yang, Peng; Kong, Jichuan; Li, Dandan; Miao, Juan; Hua, Shaofeng; Hu, Chaobing

    2016-11-01

    The inhibitory effects of nine ionic liquids (ILs) on the catalase activity were investigated using fluorescence, absorption ultraviolet-visible spectroscopy. The interactions of ILs and catalase on the molecular level were studied. The experimental results indicated that ILs could inhibit the catalase activity and their inhibitory abilities depended on their chemical structures. Fluorescence experiments showed that hydrogen bonding played an important role in the interaction process. The inhibitory abilities of ILs on catalase activity could be simply described by their hydrophobicity and hydrogen bonding abilities. Unexpected less inhibitory effects of trifluoromethanesulfonate (TfO - ) might be ascribed to its larger size, which makes it difficult to go through the substrate channel of catalase to the active site. © The Author(s) 2016.

  4. Phototherapy appliances, their ultraviolet radiation and quality assurance of phototherapy; Terveydenhuollon laadunhallinta. Valohoitolaitteet, niiden UV- saeteily ja valohoitojen laadunvarmistus

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Leszczynski, K.; Visuri, R.; Ylianttila, L.; Jokela, K. [Radiation and Nuclear Safety Authority, Helsinki (Finland)

    1998-12-31

    Artificial UV radiation (UVR) is used in the treatment of psoriasis and other skin diseases. Long term phototherapy is associated to increased risk of squamous cell carcinoma. This report gives a short review of biological effects of UVR and technical aspects of phototherapy units. The phototherapy units used in Finnish Central hospitals are described and the measured UVR dose rates of these units are presented. In addition, the UVR meters used in hospitals are described and the calibration factors are given for UVR dose rate measurements: Finally, recommendations are given for the quality assurance of photo-therapy units as well as for assessing UVR doses of patients. (orig.) 88 refs.

  5. Phototherapy appliances, their ultraviolet radiation and quality assurance of phototherapy. Terveydenhuollon laadunhallinta. Valohoitolaitteet, niiden UV- saeteily ja valohoitojen laadunvarmistus

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Leszczynski, K.; Visuri, R.; Ylianttila, L.; Jokela, K. (Radiation and Nuclear Safety Authority, Helsinki (Finland))

    1998-01-01

    Artificial UV radiation (UVR) is used in the treatment of psoriasis and other skin diseases. Long term phototherapy is associated to increased risk of squamous cell carcinoma. This report gives a short review of biological effects of UVR and technical aspects of phototherapy units. The phototherapy units used in Finnish Central hospitals are described and the measured UVR dose rates of these units are presented. In addition, the UVR meters used in hospitals are described and the calibration factors are given for UVR dose rate measurements: Finally, recommendations are given for the quality assurance of photo-therapy units as well as for assessing UVR doses of patients. (orig.) 88 refs.

  6. Quality assurance of the UV irradiances of the UV-B Monitoring and Research Program: the Mauna Loa test case

    Science.gov (United States)

    Zempila, Melina Maria; Davis, John; Janson, George; Olson, Becky; Chen, Maosi; Durham, Bill; Simpson, Scott; Straube, Jonathan; Sun, Zhibin; Gao, Wei

    2017-09-01

    The USDA UV-B Monitoring and Research Program (UVMRP) is an ongoing effort aiming to establish a valuable, longstanding database of ground-based ultraviolet (UV) solar radiation measurements over the US. Furthermore, the program aims to achieve a better understanding of UV variations through time, and develop a UV climatology for the Northern American section. By providing high quality radiometric measurements of UV solar radiation, UVMRP is also focusing on advancing science for agricultural, forest, and range systems in order to mitigate climate impacts. Within these foci, the goal of the present study is to investigate, analyze, and validate the accuracy of the measurements of the UV multi-filter rotating shadowband radiometer (UV-MFRSR) and Yankee (YES) UVB-1 sensor at the high altitude, pristine site at Mauna Loa, Hawaii. The response-weighted irradiances at 7 UV channels of the UV-MFRSR along with the erythemal dose rates from the UVB-1 radiometer are discussed, and evaluated for the period 2006-2015. Uncertainties during the calibration procedures are also analyzed, while collocated groundbased measurements from a Brewer spectrophotometer along with model simulations are used as a baseline for the validation of the data. Besides this quantitative research, the limitations and merits of the existing UVMRP methods are considered and further improvements are introduced.

  7. Material and device studies for the development of ultra-violet light emitting diodes (UV-LEDS) along polar, non-polar and semi-polar directions

    Science.gov (United States)

    Chandrasekaran, Ramya

    Over the past few years, significant effort was dedicated to the development of ultraviolet light emitting diodes (UV-LEDs) for a variety of applications. Such applications include chemical and biological detection, water purification and solid-state lighting. III-Nitride LEDs based on multiple quantum wells (MQWs) grown along the conventional [0001] (polar) direction suffer from the quantum confined Stark effect (QCSE), due to the existence of strong electric fields that arise from spontaneous and piezoelectric polarization. Thus, there is strong motivation to develop MQW-based III-nitride LED structures grown along non-polar and semi-polar directions. The goal of this dissertation is to develop UV-LEDs along the [0001] polar and [11 2¯ 0] non-polar directions by the method of Molecular Beam Epitaxy (MBE). The polar and non-polar LEDs were grown on the C-plane and R-plane sapphire substrates respectively. This work is a combination of materials science studies related to the nucleation, growth and n- and p-type doping of III-nitride films on these two substrates, as well as device studies related to fabrication and characterization of UV-LEDs. It was observed that the crystallographic orientation of the III-nitride films grown on R-plane sapphire depends strongly on the kinetic conditions of growth of the Aluminum Nitride (AIN) buffer. Specifically, growth of the AIN buffer under group III-rich conditions leads to nitride films having the (11 2¯ 0) non polar planes parallel to the sapphire surface, while growth of the buffer under nitrogen rich conditions leads to nitride films with the (11 2¯ 6) semi-polar planes parallel to the sapphire surface. The electron concentration and mobility for the films grown along the polar, non-polar and semi-polar directions were investigated. P-type doping of Gallium Nitride (GaN) films grown on the nonpolar (11 2¯ 0) plane do not suffer from polarity inversion and thus the material was doped p-type with a hole concentration

  8. PMMA Wettability Caused by Ultraviolet Radiation

    OpenAIRE

    Dehtjars, J; Lancere, L; Poļaka, N; Soudnikovich, A; Tjuļkins, F; Valters, V

    2010-01-01

    The article is targeted to explore ultraviolet radiation (UV) influence on PMMAf or eye prostheses. UV beingt he Sun lightc omponenta nd could effect PMMA surface that in turn contributesi nteractionw ith tear. PMMA wettabilityw as poweredb y UV.

  9. Quantification of nimesulide in human plasma by high-performance liquid chromatography with ultraviolet detector (HPLC-UV): application to pharmacokinetic studies in 28 healthy Korean subjects.

    Science.gov (United States)

    Kim, Mi-Sun; Park, Yoo-Sin; Kim, Shin-Hee; Kim, Sang-Yeon; Lee, Min-Ho; Kim, Youn-Hee; Kim, Do-Wan; Yang, Seok-Chul; Kang, Ju-Seop

    2012-05-01

    Nimesulide is a selective COX-2 inhibitor that is as effective as the classical non-acidic nonsteroidal anti-inflammatory drugs in the relief of various pain and inflammatory conditions, but is better tolerated with lower incidences of adverse effects than other drugs. After oral dose of 100 mg nimesulide to western subjects, a mean maximal concentration (C(max)) of 2.86 ∼ 6.5 µg/mL was reached at 1.22 ∼ 2.75 h and mean t(1/2β) of 1.8 ∼ 4.74 h. This study developed a robust method for quantification of nimesulide for the pharmacokinetics and suitability of its dosage in Korea and compared its suitability with other racial populations. Nimesulide and internal standard were extracted from acidified samples with methyl tert-butyl ether and analyzed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The 28 healthy volunteers took 2 tablets of 100 mg nimesulide and blood concentrations were analyzed during the 24 h post dose. Several pharmacokinetic parameters were represented: AUC(0-infinity) = 113.0 mg-h/mL, C(max) = 12.06 mg/mL, time for maximal concentrations (T(max)) = 3.19 h and t(1/2β) = 4.51 h. These were different from those of western populations as follows: AUC was 14.5% and C(max) was 28% that of of Korean subjects and T(max) and t(1/2β) were also different. The validated HPLC-UV method was successfully applied for the pharmacokinetic studies of nimesulide in Korean subjects. Because the pharmacokinetics of nimesulide were different from western populations, its dosage regimen needs to be adjusted for Koreans. © The Author [2012]. Published by Oxford University Press. All rights reserved.

  10. Challenge and perspective: the relevance of ultraviolet (UV) radiation and the vitamin D endocrine system (VDES) for psoriasis and other inflammatory skin diseases.

    Science.gov (United States)

    Reichrath, Jörg; Saternus, Roman; Vogt, Thomas

    2017-03-16

    During evolution, the ability of many organisms to synthesize vitamin D photochemically represented, and still represents, a major driving factor for the development of life on earth. In humans because not more than 10-20% of the requirement of vitamin D can be satisfied by the diet (under most living conditions in the US and Europe), the remaining 80-90% need to be photochemically synthesized in the skin through the action of solar or artificial ultraviolet-B (UV-B) radiation. The skin is a key organ of the human body's vitamin D endocrine system (VDES), representing both the site of vitamin D synthesis and a target tissue for biologically active vitamin D metabolites. Human keratinocytes contain the enzymatic machinery (CYP27B1) for the synthesis of the biologically most active natural vitamin D metabolite 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ), representing an autonomous vitamin D 3 pathway. Cutaneous production of 1,25(OH) 2 D 3 may mediate intracrine, autocrine and paracrine effects on keratinocytes and on neighboring cells. Many skin cells (including keratinocytes, sebocytes, fibroblasts, melanocytes, macrophages and other skin immune cells) express the vitamin D receptor (VDR), an absolute pre-requisite for exerting genomic effects of 1,25(OH) 2 D 3 and analogs. The VDR is a member of the superfamily of trans-acting transcriptional regulatory factors, which also contains the steroid and thyroid hormone receptors as well as the retinoid-X receptors (RXR) and retinoic acid receptors (RAR). A large body of evidence, including cDNA microarray analyses of mRNAs, indicates that as many as 500-1000 genes may be controlled by VDR ligands that regulate a broad variety of cellular functions including growth, differentiation, and apoptosis. Clinical and laboratory investigations, including the observation that 1,25(OH) 2 D 3 is very effective in inducing the terminal differentiation and in inhibiting the proliferation of cultured human keratinocytes have resulted

  11. Applying spaceborne reflectivity measurements for calculation of the solar ultraviolet radiation at ground level

    Directory of Open Access Journals (Sweden)

    P. N. den Outer

    2012-12-01

    Full Text Available Long-term analysis of cloud effects on ultraviolet (UV radiation on the ground using spaceborne observations requires the use of instruments that have operated consecutively. The longest data record can be built from the reflectivity measurements produced by the instruments Total Ozone Mapping Spectrometers (TOMS flown on Nimbus 7 from 1979 to 1992, TOMS on Earth Probe from 1996 to 2005, and the Ozone Monitoring Instrument (OMI flown on EOS Aura since 2004. The reflectivity data produced by TOMS on Earth Probe is only included until 2002. A comparison is made with cloud effects inferred from ground-based pyranometer measurements at over 83 World Radiation Data Centre stations. Modelled UV irradiances utilizing the standard reflectivity are compared with measurements of UV irradiances at eight European low-elevation stations. The reflectivity data of the two TOMS instruments shows a consistent agreement, and the required corrections are of low percentage, i.e. 2–3%. In contrast, the reflectivity product of OMI requires correction of 7–10%, and a solar angle dependency therein is more pronounced. These corrections were inferred from a comparison with pyranometer data, and tested using the UV measurements. The average reduction of UV radiation due to clouds for all sites together indicates a small trend: a diminishing cloudiness, in line with ground-based UV observations. Uncorrected implementation of the reflectivity data would have indicated the opposite.

    An optimal area was established for reflectivity data for the calculation of daily sums of UV radiation. It measures approximately 1.25° in latitudinal direction for square-shaped areas overhead the ground-based UV stations. Such an area can be traversed within 5 to 7 h at the average wind speeds found for the West European continent.

  12. Spatial variability of ultraviolet-absorbing compounds in an aquatic liverwort and their usefulness as biomarkers of current and past UV radiation: A case study in the Atlantic–Mediterranean transition

    International Nuclear Information System (INIS)

    Monforte, Laura; Tomás-Las-Heras, Rafael; Del-Castillo-Alonso, María-Ángeles; Martínez-Abaigar, Javier; Núñez-Olivera, Encarnación

    2015-01-01

    The spatial variability of ultraviolet-absorbing compounds (UVACs) in the freshwater liverwort Jungermannia exsertifolia subsp. cordifolia was studied in mid-latitudes (the Atlantic–Mediterranean transition) across a wide lati-altitudinal gradient, with the aim of testing the usefulness of UVACs as biomarkers of current ambient levels of UV radiation. We analysed 17 samples from streams located in the main mountain ranges of the Iberian Peninsula, differentiating methanol-soluble (SUVACs, mainly located in the vacuoles) and methanol-insoluble (IUVACs, bound to cell walls) compounds, since they represent different manners to cope with UV radiation. In both fractions, the bulk level of UVACs and the concentrations of several individual compounds were measured. In addition, we measured F v /F m , DNA damage and sclerophylly index (SI) as possible additional UV biomarkers. UVACs showed a high variability, probably due not only to the gradients of macroenvironmental factors (UV radiation, PAR, and water temperature), but also to microenvironmental factors inherent to the dynamic nature of mountain streams. Two soluble coumarins were positively correlated with UV levels and could be used for ambient UV biomonitoring in the spatial scale. In contrast to the variability in UVACs, the relatively homogeneous values of F v /F m and the lack of any DNA damage made these variables useless for ambient UV biomonitoring, but suggested a strong acclimation capacity of this liverwort to changing environmental conditions (in particular, to UV levels). Finally, UVACs of fresh samples of the liverwort were compared to those of herbarium samples collected in the same lati-altitudinal gradient. SUVACs were significantly higher in fresh samples, whereas IUVACs generally showed the contrary. Thus, IUVACs were more stable than SUVACs and hence more adequate for retrospective UV biomonitoring. In conclusion, UVAC compartmentation should be taken into account for bryophyte-based UV

  13. Spatial variability of ultraviolet-absorbing compounds in an aquatic liverwort and their usefulness as biomarkers of current and past UV radiation: A case study in the Atlantic–Mediterranean transition

    Energy Technology Data Exchange (ETDEWEB)

    Monforte, Laura; Tomás-Las-Heras, Rafael; Del-Castillo-Alonso, María-Ángeles; Martínez-Abaigar, Javier, E-mail: javier.martinez@unirioja.es; Núñez-Olivera, Encarnación

    2015-06-15

    The spatial variability of ultraviolet-absorbing compounds (UVACs) in the freshwater liverwort Jungermannia exsertifolia subsp. cordifolia was studied in mid-latitudes (the Atlantic–Mediterranean transition) across a wide lati-altitudinal gradient, with the aim of testing the usefulness of UVACs as biomarkers of current ambient levels of UV radiation. We analysed 17 samples from streams located in the main mountain ranges of the Iberian Peninsula, differentiating methanol-soluble (SUVACs, mainly located in the vacuoles) and methanol-insoluble (IUVACs, bound to cell walls) compounds, since they represent different manners to cope with UV radiation. In both fractions, the bulk level of UVACs and the concentrations of several individual compounds were measured. In addition, we measured F{sub v}/F{sub m}, DNA damage and sclerophylly index (SI) as possible additional UV biomarkers. UVACs showed a high variability, probably due not only to the gradients of macroenvironmental factors (UV radiation, PAR, and water temperature), but also to microenvironmental factors inherent to the dynamic nature of mountain streams. Two soluble coumarins were positively correlated with UV levels and could be used for ambient UV biomonitoring in the spatial scale. In contrast to the variability in UVACs, the relatively homogeneous values of F{sub v}/F{sub m} and the lack of any DNA damage made these variables useless for ambient UV biomonitoring, but suggested a strong acclimation capacity of this liverwort to changing environmental conditions (in particular, to UV levels). Finally, UVACs of fresh samples of the liverwort were compared to those of herbarium samples collected in the same lati-altitudinal gradient. SUVACs were significantly higher in fresh samples, whereas IUVACs generally showed the contrary. Thus, IUVACs were more stable than SUVACs and hence more adequate for retrospective UV biomonitoring. In conclusion, UVAC compartmentation should be taken into account for bryophyte

  14. Ionic liquid-based single-drop microextraction followed by liquid chromatography-ultraviolet spectrophotometry detection to determine typical UV filters in surface water samples.

    Science.gov (United States)

    Vidal, Lorena; Chisvert, Alberto; Canals, Antonio; Salvador, Amparo

    2010-04-15

    A user-friendly and inexpensive ionic liquid-based single-drop microextraction (IL-SDME) procedure has been developed to preconcentrate trace amounts of six typical UV filters extensively used in cosmetic products (i.e., 2-hydroxy-4-methoxybenzophenone, isoamyl 4-methoxycinnamate, 3-(4'-methylbenzylidene)camphor, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-methoxycinnamate) from surface water samples prior to analysis by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). A two-stage multivariate optimization approach was developed by means of a Plackett-Burman design for screening and selecting the significant variables involved in the SDME procedure, which were later optimized by means of a circumscribed central composite design. The studied variables were drop volume, sample volume, agitation speed, ionic strength, extraction time and ethanol quantity. Owing to particularities, ionic liquid type and pH of the sample were optimized separately. Under optimized experimental conditions (i.e., 10 microL of 1-hexyl-3-methylimidazolium hexafluorophosphate, 20 mL of sample containing 1% (v/v) ethanol and NaCl free adjusted to pH 2, 37 min extraction time and 1300 rpm agitation speed) enrichment factors up to ca. 100-fold were obtained depending on the target analyte. The method gave good levels of repeatability with relative standard deviations varying between 2.8 and 8.8% (n=6). Limits of detection were found in the low microg L(-1) range, varying between 0.06 and 3.0 microg L(-1) depending on the target analyte. Recovery studies from different types of surface water samples collected during the winter period, which were analysed and confirmed free of all target analytes, ranged between 92 and 115%, showing that the matrix had a negligible effect upon extraction. Finally, the proposed method was applied to the analysis of different water samples (taken from two beaches, two swimming pools and a

  15. Ultraviolet Communication for Medical Applications

    Science.gov (United States)

    2015-06-01

    DEI procured several UVC phosphors and tested them with vacuum UV (VUV) excitation. Available emission peaks include: 226 nm, 230 nm, 234 nm, 242...SUPPLEMENTARY NOTES Report contains color. 14. ABSTRACT Under this Phase II SBIR effort, Directed Energy Inc.’s (DEI) proprietary ultraviolet ( UV ...15. SUBJECT TERMS Non-line-of-sight (NLOS), networking, optical communication, plasma-shells, short range, ultraviolet ( UV ) light 16. SECURITY

  16. 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

  17. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

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

  18. Calibration of Ground -based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Yordanova, Ginka

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...

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

    Directory of Open Access Journals (Sweden)

    M. M. Kvalevåg

    2009-10-01

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

  20. 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

  1. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Staaij, J.W.M. van de; Ernst, W. H.O.; Hakvoort, H. W.J.; Rozema, J. [Vrije Univ., Amsterdam (Netherlands)

    1995-07-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  2. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    International Nuclear Information System (INIS)

    Staaij, J.W.M. van de; Ernst, W.H.O.; Hakvoort, H.W.J.; Rozema, J.

    1995-01-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  3. Space and Ground-Based Infrastructures

    Science.gov (United States)

    Weems, Jon; Zell, Martin

    This chapter deals first with the main characteristics of the space environment, outside and inside a spacecraft. Then the space and space-related (ground-based) infrastructures are described. The most important infrastructure is the International Space Station, which holds many European facilities (for instance the European Columbus Laboratory). Some of them, such as the Columbus External Payload Facility, are located outside the ISS to benefit from external space conditions. There is only one other example of orbital platforms, the Russian Foton/Bion Recoverable Orbital Capsule. In contrast, non-orbital weightless research platforms, although limited in experimental time, are more numerous: sounding rockets, parabolic flight aircraft, drop towers and high-altitude balloons. In addition to these facilities, there are a number of ground-based facilities and space simulators, for both life sciences (for instance: bed rest, clinostats) and physical sciences (for instance: magnetic compensation of gravity). Hypergravity can also be provided by human and non-human centrifuges.

  4. Illumination compensation in ground based hyperspectral imaging

    Science.gov (United States)

    Wendel, Alexander; Underwood, James

    2017-07-01

    Hyperspectral imaging has emerged as an important tool for analysing vegetation data in agricultural applications. Recently, low altitude and ground based hyperspectral imaging solutions have come to the fore, providing very high resolution data for mapping and studying large areas of crops in detail. However, these platforms introduce a unique set of challenges that need to be overcome to ensure consistent, accurate and timely acquisition of data. One particular problem is dealing with changes in environmental illumination while operating with natural light under cloud cover, which can have considerable effects on spectral shape. In the past this has been commonly achieved by imaging known reference targets at the time of data acquisition, direct measurement of irradiance, or atmospheric modelling. While capturing a reference panel continuously or very frequently allows accurate compensation for illumination changes, this is often not practical with ground based platforms, and impossible in aerial applications. This paper examines the use of an autonomous unmanned ground vehicle (UGV) to gather high resolution hyperspectral imaging data of crops under natural illumination. A process of illumination compensation is performed to extract the inherent reflectance properties of the crops, despite variable illumination. This work adapts a previously developed subspace model approach to reflectance and illumination recovery. Though tested on a ground vehicle in this paper, it is applicable to low altitude unmanned aerial hyperspectral imagery also. The method uses occasional observations of reference panel training data from within the same or other datasets, which enables a practical field protocol that minimises in-field manual labour. This paper tests the new approach, comparing it against traditional methods. Several illumination compensation protocols for high volume ground based data collection are presented based on the results. The findings in this paper are

  5. A Fourier transform spectrometer without a beam splitter for the vacuum ultraviolet range: From the optical design to the first UV spectrum.

    Science.gov (United States)

    de Oliveira, N; Joyeux, D; Phalippou, D; Rodier, J C; Polack, F; Vervloet, M; Nahon, L

    2009-04-01

    We describe a Fourier transform (FT) spectrometer designed to operate down to 60 nm (20 eV) on a synchrotron radiation beamline for high resolution absorption spectrometry. As far as we know, such an instrument is not available below 140 nm mainly because manufacturing accurate and efficient beam splitters remains a major problem at these wavelengths, especially if a wide bandwidth operation is desired. In order to overcome this difficulty, we developed an interferometer based on wave front division instead of amplitude division. It relies on a modified Fresnel bimirror configuration that requires only flat mirrors. The instrument provides path difference scanning through the translation of one reflector. During the scanning, the moving reflector is controlled by an optical system that keeps its direction constant within a tolerable value and provides an accurate interferometric measurement of the path difference variation. Therefore, a regular interferogram sampling is obtained, producing a nominal spectral impulse response and an accurate spectral calibration. The first results presented in this paper show a measured spectral resolution of delta(sigma)=0.33 cm-1 (interval between spectral samples). This was obtained with a sampling interval of 29 nm (path difference) and 512 K samples from a one-sided interferogram using a cosine FT. Such a sampling interval should allow the recording of large bandwidth spectra down to lambda=58 nm with an ultimate resolving power of 500,000 at this wavelength. In order to check the instrument performances, we first recorded an interferogram from a He-Ne stabilized laser. This provided the actual spectral impulse function, which was found to be fully satisfactory. The determination of the impulse response distortion and of the noise on the vacuum ultraviolet (VUV) spectral range provided accurate information in the sampling error profile over a typical scan. Finally, the instrument has been moved to the SU5 undulator

  6. Intercomparison of ground-based ozone and NO2 measurements during the MANTRA 2004 campaign

    Directory of Open Access Journals (Sweden)

    K. Strong

    2007-11-01

    Full Text Available The MANTRA (Middle Atmosphere Nitrogen TRend Assessment 2004 campaign took place in Vanscoy, Saskatchewan, Canada (52° N, 107° W from 3 August to 15 September, 2004. In support of the main balloon launch, a suite of five zenith-sky and direct-Sun-viewing UV-visible ground-based spectrometers was deployed, primarily measuring ozone and NO2 total columns. Three Fourier transform spectrometers (FTSs that were part of the balloon payload also performed ground-based measurements of several species, including ozone. Ground-based measurements of ozone and NO2 differential slant column densities from the zenith-viewing UV-visible instruments are presented herein. They are found to partially agree within NDACC (Network for the Detection of Atmospheric Composition Change standards for instruments certified for process studies and satellite validation. Vertical column densities of ozone from the zenith-sky UV-visible instruments, the FTSs, a Brewer spectrophotometer, and ozonesondes are compared, and found to agree within the combined error estimates of the instruments (15%. NO2 vertical column densities from two of the UV-visible instruments are compared, and are also found to agree within combined error (15%.

  7. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Gómez Arranz, Paula

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  8. Ground-Based Telescope Parametric Cost Model

    Science.gov (United States)

    Stahl, H. Philip; Rowell, Ginger Holmes

    2004-01-01

    A parametric cost model for ground-based telescopes is developed using multi-variable statistical analysis, The model includes both engineering and performance parameters. While diameter continues to be the dominant cost driver, other significant factors include primary mirror radius of curvature and diffraction limited wavelength. The model includes an explicit factor for primary mirror segmentation and/or duplication (i.e.. multi-telescope phased-array systems). Additionally, single variable models based on aperture diameter are derived. This analysis indicates that recent mirror technology advances have indeed reduced the historical telescope cost curve.

  9. Validation of ultraviolet radiation budgets using satellite observations from the OMI instrument

    Energy Technology Data Exchange (ETDEWEB)

    Den Outer, P.N.; Van Dijk, A.; Slaper, H.

    2008-11-15

    Satellite retrieval of ozone, clouds, aerosols and ground albedo allows the modelling of ultraviolet (UV)-doses received at the ground. UV-doses derived from satellite observations are highly useful in analyzing regional differences in the effects of ozone depletion and climate change on the biologically effective UV-radiation levels. RIVM has developed and used UV-mapping and UV-risk mapping techniques in environmental assessments in evaluating the effects of ozone depletion and climate change. This project provides a validation study on the OMUVB product by means of a comparison with ground-based measurements. This validation should demonstrate if the OMUVB product can be used from the perspective of long-term environmental trend assessments. Comparing ground-based UV-measurements with the OMUVB product, we show that the product consistently overestimates the UV-doses received at the ground in Europe. The systematic comparison with data from 8 European sites shows on average a 15% overestimate in the yearly integrated UV with a site-to-site variability of around 8%. For four of the more northern sites the overestimation in yearly doses is between 5-10%, and for the four sites that are more southern the deviation is 20-27%. Using the ozone and reflectivity data from the OMI-instrument (Ozone Monitoring Instrument) in combination with the AMOUR-algorithm (Assessment Model for Ultraviolet radiation and Risks) shows smaller overestimates of on average 5-6% with a similar variability between the sites. The variability between sites is largely caused by aerosol and albedo effects and is reduced to 3% if local data on aerosol and albedo are used. The overestimates in the OMUVB product are primarily due to too low (tropospheric) aerosol loads used for the European sites. In addition, our comparison shows that under heavy clouded conditions the cloud modification factors are too high. This contributes to the overall too high UV-doses of the OMUVB product. Environmental

  10. Validation of ultraviolet radiation budgets using satellite observations from the OMI instrument

    International Nuclear Information System (INIS)

    Den Outer, P.N.; Van Dijk, A.; Slaper, H.

    2008-11-01

    Satellite retrieval of ozone, clouds, aerosols and ground albedo allows the modelling of ultraviolet (UV)-doses received at the ground. UV-doses derived from satellite observations are highly useful in analyzing regional differences in the effects of ozone depletion and climate change on the biologically effective UV-radiation levels. RIVM has developed and used UV-mapping and UV-risk mapping techniques in environmental assessments in evaluating the effects of ozone depletion and climate change. This project provides a validation study on the OMUVB product by means of a comparison with ground-based measurements. This validation should demonstrate if the OMUVB product can be used from the perspective of long-term environmental trend assessments. Comparing ground-based UV-measurements with the OMUVB product, we show that the product consistently overestimates the UV-doses received at the ground in Europe. The systematic comparison with data from 8 European sites shows on average a 15% overestimate in the yearly integrated UV with a site-to-site variability of around 8%. For four of the more northern sites the overestimation in yearly doses is between 5-10%, and for the four sites that are more southern the deviation is 20-27%. Using the ozone and reflectivity data from the OMI-instrument (Ozone Monitoring Instrument) in combination with the AMOUR-algorithm (Assessment Model for Ultraviolet radiation and Risks) shows smaller overestimates of on average 5-6% with a similar variability between the sites. The variability between sites is largely caused by aerosol and albedo effects and is reduced to 3% if local data on aerosol and albedo are used. The overestimates in the OMUVB product are primarily due to too low (tropospheric) aerosol loads used for the European sites. In addition, our comparison shows that under heavy clouded conditions the cloud modification factors are too high. This contributes to the overall too high UV-doses of the OMUVB product. Environmental

  11. Space weather effects on ground based technology

    Science.gov (United States)

    Clark, T.

    Space weather can affect a variety of forms of ground-based technology, usually as a result of either the direct effects of the varying geomagnetic field, or as a result of the induced electric field that accompanies such variations. Technologies affected directly by geomagnetic variations include magnetic measurements made d ringu geophysical surveys, and navigation relying on the geomagnetic field as a direction reference, a method that is particularly common in the surveying of well-bores in the oil industry. The most obvious technology affected by induced electric fields during magnetic storms is electric power transmission, where the example of the blackout in Quebec during the March 1989 magnetic storm is widely known. Additionally, space weather effects must be taken into account in the design of active cathodic protection systems on pipelines to protect them against corrosion. Long-distance telecommunication cables may also have to be designed to cope with space weather related effects. This paper reviews the effects of space weather in these different areas of ground-based technology, and provides examples of how mitigation against hazards may be achieved. (The paper does not include the effects of space weather on radio communication or satellite navigation systems).

  12. ULTRAVIOLET TECHNOLOGY FOR FOOD PRESERVATION

    OpenAIRE

    Guedes, AMM; Novello, D; Mendes, GMD; Cristianini, M

    2009-01-01

    ULTRAVIOLET TECHNOLOGY FOR FOOD PRESERVATION This literature review article had as objective to gather information about ultraviolet (UV) technology utilization on the food industry, its effects and potential application. Aspects as the origin, concept and applications of the technology on the equipment industry and running mechanisms were approached. The application of UV radiation on food decontamination is still little used due its low penetration, but it is known that it can be easily app...

  13. Egg hatching response to a range of ultraviolet-B (UV-B) radiation doses for four predatory mites and the herbivorous spider mite Tetranychus urticae.

    Science.gov (United States)

    Koveos, Dimitrios S; Suzuki, Takeshi; Terzidou, Anastasia; Kokkari, Anastasia; Floros, George; Damos, Petros; Kouloussis, Nikos A

    2017-01-01

    Egg hatchability of four predatory mites-Phytoseiulus persimilis Athias-Henriot, Iphiseius [Amblyseius] degenerans Berlese, Amblyseius swirskii Athias-Henriot, and Euseius finlandicus Oudemans (Acari: Phytoseiidae)-and the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) was determined under various UV-B doses either in constant darkness (DD) or with simultaneous irradiation using white light. Under UV-B irradiation and DD or simultaneous irradiation with white light, the predator's eggs hatched in significantly lower percentages than in the control non-exposed eggs, which indicates deleterious effects of UV-B on embryonic development. In addition, higher hatchability percentages were observed under UV-B irradiation and DD in eggs of the predatory mites than in eggs of T. urticae. This might be caused by a higher involvement of an antioxidant system, shield effects by pigments or a mere shorter duration of embryonic development in predatory mites than in T. urticae, thus avoiding accumulative effects of UV-B. Although no eggs of T. urticae hatched under UV-B irradiation and DD, variable hatchability percentages were observed under simultaneous irradiation with white light, which suggests the involvement of a photoreactivation system that reduces UV-B damages. Under the same doses with simultaneous irradiation with white light, eggs of T. urticae displayed higher photoreactivation and were more tolerant to UV-B than eggs of the predatory mites. Among predators variation regarding the tolerance to UV-B effects was observed, with eggs of P. persimilis and I. degenerans being more tolerant to UV-B radiation than eggs of A. swirskii and E. finlandicus.

  14. Accelerated Solar-UV Test Chamber

    Science.gov (United States)

    Gupta, A.; Laue, E. G.

    1984-01-01

    Medium-pressure mercury-vapor lamps provide high ratio of ultraviolet to total power. Chamber for evaluating solar-ultraviolet (UV) radiation damage permits accelerated testing without overheating test specimens.

  15. UV Lidar Receiver Analysis for Tropospheric Sensing of Ozone

    Science.gov (United States)

    Pliutau, Denis; DeYoung, Russell J.

    2013-01-01

    A simulation of a ground based Ultra-Violet Differential Absorption Lidar (UV-DIAL) receiver system was performed under realistic daytime conditions to understand how range and lidar performance can be improved for a given UV pulse laser energy. Calculations were also performed for an aerosol channel transmitting at 3 W. The lidar receiver simulation studies were optimized for the purpose of tropospheric ozone measurements. The transmitted lidar UV measurements were from 285 to 295 nm and the aerosol channel was 527-nm. The calculations are based on atmospheric transmission given by the HITRAN database and the Modern Era Retrospective Analysis for Research and Applications (MERRA) meteorological data. The aerosol attenuation is estimated using both the BACKSCAT 4.0 code as well as data collected during the CALIPSO mission. The lidar performance is estimated for both diffuseirradiance free cases corresponding to nighttime operation as well as the daytime diffuse scattered radiation component based on previously reported experimental data. This analysis presets calculations of the UV-DIAL receiver ozone and aerosol measurement range as a function of sky irradiance, filter bandwidth and laser transmitted UV and 527-nm energy

  16. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  17. A study on resistance to ultraviolet radiation of POSS-TiO2/epoxy nanocomposites

    Science.gov (United States)

    Peng, Dequn; Qin, Wei; Wu, Xiaohong

    2015-06-01

    Ultraviolet (UV) radiation is a severe space environmental factor, which is harmful to the durability of the polymeric materials of the spacecraft. For this reason, a novel POSS-TiO2/EP nanocomposite was synthesized by incorporating the POSS-TiO2 organic-inorganic hybrid into the epoxy (EP) resin. The effects of UV radiation on EP resin and on POSS-TiO2/EP nanocomposites were investigated in a ground-based simulator that simulates space radiation conditions. Compared with EP resin, the value of bend strength for 5.0 wt% POSS-TiO2/EP varied in a small range before and after UV radiation. Meanwhile, a typical tough feature was observed from the SEM photo for POSS-TiO2/EP nanocomposite after UV exposure. This result indicated that the POSS-TiO2/EP exhibited the excellent properties of anti-space ultraviolet radiation. The thermo gravimetric (TG) results showed that the addition of POSS-TiO2 improved the thermal-stability of EP resin matrix. The synthesized nanocomposites in this work could be used in the satellites to enhance their adaptability to the space environment and extend their service life.

  18. Ultraviolet-B (UV-B) radiation under high-temperature conditions affects growth of rice (cv. Koshihikari) after a young panicle formation stage

    International Nuclear Information System (INIS)

    Inaba, K.

    2005-01-01

    A japonica rice (cv. Koshihikari) was used to test the effects on blooming and ripening of UV-B radiation treatment combined with high temperature treatments (day/night, 35 / 30 deg C). Strong UV-B radiation (60.4 kJ/m(2) . day) slightly increased sterility. High temperatures and weak UV-B radiation (18.1 kJ/m(2) . day) applied together from two weeks before heading and from the heading day increased sterility and those applied from two weeks after heading decreased sterility. High temperature combined with strong UV-B radiation applied from two weeks before heading increased sterility and decreased the size of unhulled grain and anther length. The same treatment given from the heading stage greatly increased sterility and decreased anther length and pollen production, and that given two weeks after heading decreased unhulled grain weight. It also decreased photosynthetic rate in Flag leaves. A high temperature applied together with strong UV-B radiation had a synergistic effect causing poor growth; it increased the harmful effects of a high temperature and strong UV-B given separately, on the sterility and pollen formation

  19. Ultraviolet radiation (UV-C) on the post harvest control of Colletotrichum gloeosporioides in 'niagara rosada' grapes;Radiacao ultravioleta no controle pos-colheita de Colletotrichum gloeosporides em uva 'niagara rosada'

    Energy Technology Data Exchange (ETDEWEB)

    Cia, Patricia; Sanches, Juliana, E-mail: pcia@iac.sp.gov.b [Instituto Agronomico de Campinas (IAC), Jundiai, SP (Brazil). Centro de Engenharia e Automacao; Benato, Eliane Aparecida; Valentini, Silvia Regina de Toledo; Anjos, Valeria Delgado de Almeida [Instituto de Tecnologia de Alimentos (ITAL), Campinas, SP (Brazil). Grupo de Engenharia e Pos-Colheita; Ponzo, Francine Scolfaro [Instituto Agronomico de Campinas (IAC), SP (Brazil); Terra, Maurilo Monteiro [Instituto Agronomico de Campinas (IAC), SP (Brazil). Centro de Ecofisiologia e Biofisica

    2009-07-01

    Most of the post harvest losses of 'Niagara Rosada' grapes are caused by rot and detached berries. Recently, many researches on alternative methods, such as physical treatments, have been carried out in order to control rots and extend the shelf life of fruits. The objective of this research was to evaluate the effect of ultraviolet radiation (UV-C) on the control of C. gloeosporioides in 'Niagara Rosada' grapes stored at room condition and under refrigeration. Clusters of 'Niagara Rosada' grapes were inoculated with the pathogen and submitted 2 hours later to different doses of UV-C, 0, 1.05, 2.09, 4.18, and 8.35 kJ m{sup -}2, during the periods of 0, 1, 2, 4, and 8 min, respectively. Then, the clusters were stored under two conditions: 25 +- 1 deg C / 80 +- 5 % RH for 7 days, and at 1 +- 1 deg C / 90 +- 5 % RH for 16 days followed by storage at 25 +- 1 deg C / 80 +- 5 %RH for 5 more days. The grapes were evaluated for rot incidence, stem browning, color of the berries, percentage of detached berries, titratable acidity, total soluble solids, and ratio. It was observed that UV-C radiation was effective in reducing the incidence of C. gloeosporioides on inoculated 'Niagara Rosada' grapes and did not change the physicochemical characteristics of the grapes. (author)

  20. Hubble Space Telescope Ultraviolet Light Curves Reveal Interesting Properties of CC Sculptoris and RZ Leonis

    Energy Technology Data Exchange (ETDEWEB)

    Szkody, Paula; Mukadam, Anjum S. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Toloza, Odette; Gänsicke, Boris T.; Pala, Anna F. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Dai, Zhibin [Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216 (China); Waagen, Elizabeth O. [AAVSO, 48 Bay State Rd, Cambridge, MA 02138 (United States); Godon, Patrick; Sion, Edward M., E-mail: szkody@astro.washington.edu [Department of Astrophysics and Planetary Science, Villanova University, Villanova, PA 19085 (United States)

    2017-03-01

    Time-tag ultraviolet data obtained on the Hubble Space Telescope in 2013 reveal interesting variability related to the white dwarf spin in the two cataclysmic variables RZ Leo and CC Scl. RZ Leo shows a period at 220 s and its harmonic at 110 s, thus identifying it as a likely Intermediate Polar (IP). The spin signal is not visible in a short single night of ground-based data in 2016, but the shorter exposures in that data set indicate a possible partial eclipse. The much larger UV amplitude of the spin signal in the known IP CC Scl allows the spin of 389 s, previously only seen at outburst, to be visible at quiescence. Spectra created from the peaks and troughs of the spin times indicate a hotter temperature of several thousand degrees during the peak phases, with multiple components contributing to the UV light.

  1. 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

  2. Ocena wiedzy uczniów warszawskich szkół średnich na temat skutków zdrowotnych wynikających z nadmiernego korzystania z promieniowania ultrafioletowego (UV = Knowledge assessment about health effects caused by excessive use of ultraviolet radiation (UV among high school students in Warsaw

    Directory of Open Access Journals (Sweden)

    Paweł Koczkodaj

    2016-05-01

    Abstract 1. Introduction and aim Ultraviolet radiation is present in the daily life of every human being. The constantly growing number of new cases of skin cancer in Poland and in the world can suggest a lack of adequate knowledge of photoprotection. Raising public awareness, especially among young people about the health effects of excessive UV radiation use, plays a key role in relation to their current and future health. The aim of the study was to assess the level of knowledge among high school students in Warsaw about the health effects resulting from excessive use of ultraviolet radiation, as well as knowledge concerning health behaviors of young people using UV radiation. 2. Material and methods The study group consists of 153 students from Warsaw high schools. The gender distribution was random, the age range of the respondents was 17 to 19 years. The study was conducted using paper questionnaire, consisting of 29 questions. To examine the relationship between the selected traits has been applied test of independence chi-square (χ2 (STATISTICA12 package. In tests the level of significance was p≤0.05. Depending on the size used appropriate amendments to the chi-square test. 3. Results and conclusions There was no relationship between such features as: the use of tanning devices and perception of skin burns as a carcinogenic factor, the use of the solarium and regularly reviewing pigmented moles, the occurrence of malignant melanoma of the skin in the past in the family and the use of tanning devices, the occurrence of skin burns and frequency of use of formulations with UV protection. This may indicate incomplete knowledge of the respondents in terms of the impact of UV on human health.

  3. New technologies for UV detectors

    Science.gov (United States)

    Joseph, C. L.

    1993-01-01

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

  4. SCIENTIFIC EFFICIENCY OF GROUND-BASED TELESCOPES

    International Nuclear Information System (INIS)

    Abt, Helmut A.

    2012-01-01

    I scanned the six major astronomical journals of 2008 for all 1589 papers that are based on new data obtained from ground-based optical/IR telescopes worldwide. Then I collected data on numbers of papers, citations to them in 3+ years, the most-cited papers, and annual operating costs. These data are assigned to four groups by telescope aperture. For instance, while the papers from telescopes with an aperture >7 m average 1.29 more citations than those with an aperture of 2 to 7 m) telescopes. I wonder why the large telescopes do so relatively poorly and suggest possible reasons. I also found that papers based on archival data, such as the Sloan Digital Sky Survey, produce 10.6% as many papers and 20.6% as many citations as those based on new data. Also, the 577.2 papers based on radio data produced 36.3% as many papers and 33.6% as many citations as the 1589 papers based on optical/IR telescopes.

  5. Ultraviolet radiation, human health, and the urban forest

    Science.gov (United States)

    Gordon M. Heisler; Richard H. Grant

    2000-01-01

    Excess exposure to ultraviolet (UV) radiation from the sun, particularly the ultraviolet B (UVB) portion, has been linked with adverse effects on human health ranging from skin cancers to eye diseases such as cataracts. Trees may prevent even greater disease rates in humans by reducing UV exposure. Tree shade greatly reduces UV irradiance when both the sun and sky are...

  6. From ultraviolet to Prussian blue: a spectral response for the cyanotype process and a safe educational activity to explain UV exposure for all ages.

    Science.gov (United States)

    Turner, J; Parisi, A V; Downs, N; Lynch, M

    2014-12-01

    Engaging students and the public in understanding UV radiation and its effects is achievable using the real time experiment that incorporates blueprint paper, an "educational toy" that is a safe and easy demonstration of the cyanotype chemical process. The cyanotype process works through the presence of UV radiation. The blueprint paper was investigated to be used as not only engagement in discussion for public outreach about UV radiation, but also as a practical way to introduce the exploration of measurement of UV radiation exposure and as a consequence, digital image analysis. Tests of print methods and experiments, dose response, spectral response and dark response were investigated. Two methods of image analysis for dose response calculation are provided using easy to access software and two methods of pixel count analysis were used to determine spectral response characteristics. Variation in manufacture of the blueprint paper product indicates some variance between measurements. Most importantly, as a result of this investigation, a preliminary spectral response range for the radiation required to produce the cyanotype reaction is presented here, which has until now been unknown.

  7. Validation of an Innovative Satellite-Based UV Dosimeter

    Science.gov (United States)

    Morelli, Marco; Masini, Andrea; Simeone, Emilio; Khazova, Marina

    2016-08-01

    We present an innovative satellite-based UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in-vivo assessment of the erythemal effects on some volunteers having a controlled exposure to solar radiation.Both validations showed that the satellite-based UV dosimeter has a good accuracy and reliability needed for health-related applications.The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. This app will be launched on the global market by siHealth Ltd in May 2016 under the name of "HappySun" and available both for Android and for iOS devices (more info on http://www.happysun.co.uk).Extensive R&D activities are on-going for further improvement of the satellite-based UV dosimeter's accuracy.

  8. The GALEX Ultraviolet Virgo Cluster Survey (GUViCS). VII. Brightest cluster galaxy UV upturn and the FUV-NUV color up to redshift 0.35

    Science.gov (United States)

    Boissier, S.; Cucciati, O.; Boselli, A.; Mei, S.; Ferrarese, L.

    2018-03-01

    Context. At low redshift, early-type galaxies often exhibit a rising flux with decreasing wavelength in the 1000-2500 Å range, called "UV upturn". The origin of this phenomenon is debated, and its evolution with redshift is poorly constrained. The observed GALEX FUV-NUV color can be used to probe the UV upturn approximately to redshift 0.5. Aim. We provide constraints on the existence of the UV upturn up to redshift 0.4 in the brightest cluster galaxies (BCG) located behind the Virgo cluster, using data from the GUViCS survey. Methods: We estimate the GALEX far-UV (FUV) and near-UV (NUV) observed magnitudes for BCGs from the maxBCG catalog in the GUViCS fields. We increase the number of nonlocal galaxies identified as BCGs with GALEX photometry from a few tens of galaxies to 166 (64 when restricting this sample to relatively small error bars). We also estimate a central color within a 20 arcsec aperture. By using the r-band luminosity from the maxBCG catalog, we can separate blue FUV-NUV due to recent star formation and candidate upturn cases. We use Lick indices to verify their similarity to redshift 0 upturn cases. Results: We clearly detect a population of blue FUV-NUV BCGs in the redshift range 0.10-0.35, vastly improving the existing constraints at these epochs by increasing the number of galaxies studied, and by exploring a redshift range with no previous data (beyond 0.2), spanning one more Gyr in the past. These galaxies bring new constraints that can help distinguish between assumptions concerning the stellar populations causing the UV upturn phenomenon. The existence of a large number of UV upturns around redshift 0.25 favors the existence of a binary channel among the sources proposed in the literature. Tables 2-5 are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A42

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

    Directory of Open Access Journals (Sweden)

    F. Jégou

    2011-12-01

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

  10. 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.

  11. Atomic Data for Stellar Astrophysics: from the UV to the IR

    Science.gov (United States)

    Wahlgren, Glenn M.

    2011-01-01

    The study of stars and stellar evolution relies heavily on the analysis of stellar spectra. The need for atomic line data from the ultraviolet (UV) to the infrared (lR) regions is greater now than ever. In the past twenty years, the time since the launch of the Hubble Space Telescope, great progress has been made in acquiring atomic data for UV transitions. The optical wavelength region, now expanded by progress in detector technology, continues to provide motivation for new atomic data. In addition, investments in new instrumentation for ground-based and space observatories has lead to the availability of high-quality spectra at IR wavelengths, where the need for atomic data is most critical. In this review, examples are provided of the progress made in generating atomic data for stellar studies, with a look to the future for addressing the accuracy and completeness of atomic data for anticipated needs.

  12. Assessment of Transition Element Speciation in Glasses Using a Portable Transmission Ultraviolet-Visible-Near-Infrared (UV-Vis-NIR) Spectrometer.

    Science.gov (United States)

    Hunault, Myrtille; Lelong, Gérald; Gauthier, Michel; Gélébart, Frédéric; Ismael, Saindou; Galoisy, Laurence; Bauchau, Fanny; Loisel, Claudine; Calas, Georges

    2016-05-01

    A new low-cost experimental setup based on two compact dispersive optical spectrometers has been developed to measure optical absorption transmission spectra over the 350-2500 nm energy range. We demonstrate how near-infrared (NIR) data are essential to identify the coloring species in addition to ultraviolet visible data. After calibration with reference glasses, the use of an original sample stage that maintains the window panel in the vertical position enables the comparison of ancient and modern glasses embedded in a panel from the Sainte-Chapelle of Paris, without any sampling. The spectral resolution enables to observe fine resonances arising in the absorption bands of Cr(3+), and the complementary information obtained in the NIR enables to determine the contribution of Fe(2+), a key indicator of glassmaking conditions. © The Author(s) 2016.

  13. Transparent ultraviolet photovoltaic cells.

    Science.gov (United States)

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  14. Photodegradation of the UV filter ethylhexyl methoxycinnamate under ultraviolet light: Identification and in silico assessment of photo-transformation products in the context of grey water reuse.

    Science.gov (United States)

    Jentzsch, F; Olsson, O; Westphal, J; Reich, M; Leder, C; Kümmerer, K

    2016-12-01

    To prevent water shortages in the future and to reduce domestic water consumption, decentralized grey water (GW) reuse has become increasingly important. This water has, however, to be free of pollutants. Conventional treatment of GW does not fully eliminate micropollutants such as the UV filter substance ethylhexyl methoxycinnamate (EHMC). EHMC, which is commonly used in sunscreens and personal care products, is an endocrine disruptor and shows potential to bioaccumulation, which is also reflected in its low water solubility. Photolysis has been proposed as an alternative treatment method for other micropollutants, but it is not clear yet whether it can also be used to eliminate EHMC. One goal of this study was to better understand the basic pathways involved in this process. It aimed to identify photo-transformation products (photo-TPs) by using, in the test conditions, an initial concentration of EHMC higher than those expected in the environment. Acetonitrile (ACN) was added in low concentrations to the aqueous solution to overcome the low aquatic solubility of EHMC. The influence of this co-solvent on the degradation kinetics was studied. The photolysis experiments were carried out using a medium pressure mercury lamp, which emits UV light in the range of 200-400nm. The quantum yield of the photolysis of EHMC was 0.0042 and 0.0023mol·Einstein -1 (for 0.2 and 0.5% ACN (v/v), respectively), and the relative and absolute UV photon fluxes were determined. HPLC was used to monitor the elimination kinetics of EHMC, which followed first-order kinetics. The results of LC-MS n analyses revealed that beside others, several oxidized and hydroxylized EHMC isomers were formed as photo-TPs in aqueous solution. Using a set of in silico quantitative structure-activity relationship (QSAR) models, this study also offered new insights concerning the environmental fate and toxicity of the TPs of EHMC. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Ultraviolet spectrophotometer for measuring columnar atmospheric ozone from aircraft

    Science.gov (United States)

    Hanser, F. A.; Sellers, B.; Briehl, D. C.

    1978-01-01

    An ultraviolet spectrophotometer (UVS) to measure downward solar fluxes from an aircraft or other high altitude platform is described. The UVS uses an ultraviolet diffuser to obtain large angular response with no aiming requirement, a twelve-position filter wheel with narrow (2-nm) and broad (20-nm) bandpass filters, and an ultraviolet photodiode. The columnar atmospheric ozone above the UVS (aircraft) is calculated from the ratios of the measured ultraviolet fluxes. Comparison with some Dobson station measurements gives agreement to 2%. Some UVS measured ozone profiles over the Pacific Ocean for November 1976 are shown to illustrate the instrument's performance.

  16. Ultraviolet disinfection of potable water

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, R. L. [Metropolitan Water District of Southern California, Los Angeles, CA (United States)

    1990-06-15

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection.

  17. Ultraviolet disinfection of potable water

    International Nuclear Information System (INIS)

    Wolfe, R.L.

    1990-01-01

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-15

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

  19. Validation and in vivo assessment of an innovative satellite-based solar UV dosimeter for a mobile app dedicated to skin health.

    Science.gov (United States)

    Morelli, M; Masini, A; Simeone, E; Khazova, M

    2016-08-31

    We present an innovative satellite-based solar UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in vivo assessment of the erythemal effects on some volunteers having controlled exposure to solar radiation. The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. Both validations showed that the system has a good accuracy and reliability needed for health-related applications. This app will be launched on the market by siHealth Ltd in May 2016 under the name of "HappySun" and is available for both Android and iOS devices (more info on ). Extensive R&D activities are on-going for the further improvement of the satellite-based UV dosimeter's accuracy.

  20. Ultraviolet signals in birds are special.

    OpenAIRE

    Hausmann, Franziska; Arnold, Kathryn E; Marshall, N Justin; Owens, Ian P F

    2003-01-01

    Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a si...

  1. Nanoscale freestanding gratings for ultraviolet blocking filters

    Energy Technology Data Exchange (ETDEWEB)

    van Beek, J.T.; Fleming, R.C.; Hindle, P.S.; Prentiss, J.D.; Schattenburg, M.L. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ritzau, S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1998-11-01

    Ultraviolet (UV) blocking filters are needed for atomic flux imaging in environments where high levels of ultraviolet radiation are present. Freestanding gratings are a promising candidate for UV filtering. They have a high aspect ratio ({approximately}13), narrow ({approximately}40 nm) slots, and effectively block UV radiation. The grating fabrication process makes use of several etching, electroplating, and lithographic steps and includes an optional step to plug pinholes induced by particles during processing. Gratings were successfully manufactured and tested. Measured UV transmissions of {approximately}10{sup {minus}5} and particle transmissions of {approximately}10{percent} are in agreement with theoretical predictions. {copyright} {ital 1998 American Vacuum Society.}

  2. '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.

  3. 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 ...

  4. KSC ADVANCED GROUND BASED FIELD MILL V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Advanced Ground Based Field Mill (AGBFM) network consists of 34 (31 operational) field mills located at Kennedy Space Center (KSC), Florida. The field mills...

  5. UV Tanning Equipment | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

    Sun lamps and tanning equipment emit ultraviolet (UV) rays. People who are exposed to UV rays over a long period of time are more likely to develop skin cancer. People with light skin are in more danger because their skin is more sensitive to UV rays.

  6. Ultraviolet B radiation increases hairless mouse mast cells in a dose-dependent manner and alters distribution of UV-induced mast cell growth factor

    Energy Technology Data Exchange (ETDEWEB)

    Kligman, L.H.; Murphy, G.F. [Pennsylvania Univ., Philadelphia, PA (United States). School of Medicine

    1996-01-01

    In studies of the effects of chronic UVB irradiation on dermal connective tissue in the hairless mouse, we observed that the number and size of mast cells was increased. Because mast cells are known to be associated with connective tissue remodeling, we examined and quantified the effect of increasing UVB (290-320 nm)doses on this cell. Groups of mice were exposed to filtered FS-40 Westinghouse lamps (290-400 nm: peak irradiance 313 nm) for 1-5 minimal erythema doses (MED) thrice weekly for 10 weeks. Appropriate controls were included. Biopsies, processed for light microscopy, were stained with toluidine blue. Mast cells were counted in 15 high-magnification fields per specimen with upper and lower dermis scored separately. Significant increases in large densely granular mast cells occurred at 2 MED in the lower dermic in association with the UVB-exacerbated granulomatous reaction. In the upper dermis, mast cells were significantly increased with 3 MED. These findings suggest that mast cells may play a dual role in UV-irradiated skin with those in the lower dermis related to inflammation processes and those in the upper dermis involved in connective tissue modeling. To gain understanding of the mechanism of mast cell recruitment and maturation, we examined the effect of UVB on mast cell growth factor expression. This was enhanced in the epidermis by UVB, with a shift from cytoplasmic staining to membrane-associated or intercellular staining at 2 MED and higher. Dermal dendritic and mononuclear cells also showed increased reactivity. (Author).

  7. Ultraviolet resources over Northern Eurasia.

    Science.gov (United States)

    Chubarova, Natalia; Zhdanova, Yekaterina

    2013-10-05

    We propose a new climatology of UV resources over Northern Eurasia, which includes the assessments of both detrimental (erythema) and positive (vitamin D synthesis) effects of ultraviolet radiation on human health. The UV resources are defined by using several classes and subclasses - UV deficiency, UV optimum, and UV excess - for 6 different skin types. To better quantifying the vitamin D irradiance threshold we accounted for an open body fraction S as a function of effective air temperature. The spatial and temporal distribution of UV resources was estimated by radiative transfer (RT) modeling (8 stream DISORT RT code) with 1×1° grid and monthly resolution. For this purpose special datasets of main input geophysical parameters (total ozone content, aerosol characteristics, surface UV albedo, UV cloud modification factor) have been created over the territory of Northern Eurasia. The new approaches were used to retrieve aerosol parameters and cloud modification factor in the UV spectral region. As a result, the UV resources were obtained for clear-sky and mean cloudy conditions for different skin types. We show that the distribution of UV deficiency, UV optimum and UV excess is regulated by various geophysical parameters (mainly, total ozone, cloudiness and open body fraction) and can significantly deviate from latitudinal dependence. We also show that the UV optimum conditions can be simultaneously observed for people with different skin types (for example, for 4-5 skin types at the same time in spring over Western Europe). These UV optimum conditions for different skin types occupy a much larger territory over Europe than that over Asia. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Ultraviolet laser technology and applications

    CERN Document Server

    Elliott, David L

    1995-01-01

    Ultraviolet Laser Technology and Applications is a hands-on reference text that identifies the main areas of UV laser technology; describes how each is applied; offers clearly illustrated examples of UV opticalsystems applications; and includes technical data on optics, lasers, materials, and systems. This book is unique for its comprehensive, in-depth coverage. Each chapter deals with a different aspect of the subject, beginning with UV light itself; moving through the optics, sources, and systems; and concluding with detailed descriptions of applications in various fields.The text enables pr

  9. Ultraviolet-radiation-curable paints

    Energy Technology Data Exchange (ETDEWEB)

    Grosset, A M; Su, W F.A.; Vanderglas, E

    1981-09-30

    In product finishing lines, ultraviolet radiation curing of paints on prefabricated structures could be more energy efficient than curing by natural gas fired ovens, and could eliminate solvent emission. Diffuse ultraviolet light can cure paints on three dimensional metal parts. In the uv curing process, the spectral output of radiation sources must complement the absorption spectra of pigments and photoactive agents. Photosensitive compounds, such as thioxanthones, can photoinitiate unsaturated resins, such as acrylated polyurethanes, by a free radical mechanism. Newly developed cationic photoinitiators, such as sulfonium or iodonium salts (the so-called onium salts) of complex metal halide anions, can be used in polymerization of epoxy paints by ultraviolet light radiation. One-coat enamels, topcoats, and primers have been developed which can be photoinitiated to produce hard, adherent films. This process has been tested in a laboratory scale unit by spray coating these materials on three-dimensional objects and passing them through a tunnel containing uv lamps.

  10. Ultraviolet safety assessments of insect light traps

    OpenAIRE

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

    2016-01-01

    ABSTRACT 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...

  11. Anti-Adhesion Elastomer Seal Coatings for Ultraviolet and Atomic Oxygen Protection

    Science.gov (United States)

    De Groh, Henry C., III; Puleo, Bernadette J.; Waters, Deborah L.; Miller, Sharon K.

    2015-01-01

    Radiation blocking sunscreen coatings have been developed for the protection of elastomer seals used in low-Earth-orbit (LEO). The coatings protect the seals from ultraviolet (UV) radiation and atomic oxygen (AO) damage. The coatings were developed for use on NASA docking seals. Docking seal damage from the UV and AO present in LEO can constrain mission time-line, flight mode options, and increases risk. A low level of adhesion is also required for docking seals so undocking push-off forces can be low. The coatings presented also mitigate this unwanted adhesion. Greases with low collected volatile condensable materials (CVCM) and low total mass loss (TML) were mixed with slippery and/or UV blocking powders to create the protective coatings. Coatings were applied at rates up to 2 milligrams per square centimeter. Coated seals were exposed to AO and UV in the NUV (near-UV) and UV-C wavelength ranges (300 to 400 nanometers and 254 nanometers, respectively). Ground based ashers were used to simulate the AO of space. The Sun's UV energy was mimicked assuming a nose forward flight mode, resulting in an exposure rate of 2.5 megajoules per square meter per day. Exposures between 0 and 147 megajoules per square meter (UV-C) and 245 megajoules per square meter (NUV) were accomplished. The protective coatings were durable, providing protection from UV after a simulated docking and undocking cycle. The level of protection begins to decline at coverage rates less than 0.9 milligrams per square centimeter. The leakage of seals coated with Braycote plus 20 percent Z-cote ZnO sunscreen increased by a factor of 40 after moderate AO exposure; indicating that this coating might not be suitable due to AO intolerance. Seals coated with DC-7-16.4 percent Z-cote ZnO sunscreen were not significantly affected by combined doses of 2 x 10 (sup 21) atoms per square AO with 73 megajoules per square meter UV-C. Unprotected seals were significantly damaged at UV-C exposures of 0.3 megajoules per

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

    KAUST Repository

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

    2015-01-01

    . The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely

  13. Ground-based observation of emission lines from the corona of a red-dwarf star.

    Science.gov (United States)

    Schmitt, J H; Wichmann, R

    2001-08-02

    All 'solar-like' stars are surrounded by coronae, which contain magnetically confined plasma at temperatures above 106 K. (Until now, only the Sun's corona could be observed in the optical-as a shimmering envelope during a total solar eclipse.) As the underlying stellar 'surfaces'-the photospheres-are much cooler, some non-radiative process must be responsible for heating the coronae. The heating mechanism is generally thought to be magnetic in origin, but is not yet understood even for the case of the Sun. Ultraviolet emission lines first led to the discovery of the enormous temperature of the Sun's corona, but thermal emission from the coronae of other stars has hitherto been detectable only from space, at X-ray wavelengths. Here we report the detection of emission from highly ionized iron (Fe XIII at 3,388.1 A) in the corona of the red-dwarf star CN Leonis, using a ground-based telescope. The X-ray flux inferred from our data is consistent with previously measured X-ray fluxes, and the non-thermal line width of 18.4 km s-1 indicates great similarities between solar and stellar coronal heating mechanisms. The accessibility and spectral resolution (45,000) of the ground-based instrument are much better than those of X-ray satellites, so a new window to the study of stellar coronae has been opened.

  14. Ultraviolet Extensions

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Side-by-Side Comparison Click on image for larger view This ultraviolet image from NASA's Galaxy Evolution Explorer shows the Southern Pinwheel galaxy, also know as Messier 83 or M83. It is located 15 million light-years away in the southern constellation Hydra. Ultraviolet light traces young populations of stars; in this image, young stars can be seen way beyond the main spiral disk of M83 up to 140,000 light-years from its center. Could life exist around one of these far-flung stars? Scientists say it's unlikely because the outlying regions of a galaxy are lacking in the metals required for planets to form. The image was taken at scheduled intervals between March 15 and May 20, 2007. It is one of the longest-exposure, or deepest, images ever taken of a nearby galaxy in ultraviolet light. Near-ultraviolet light (or longer-wavelength ultraviolet light) is colored yellow, and far-ultraviolet light is blue. What Lies Beyond the Edge of a Galaxy The side-by-side comparison shows the Southern Pinwheel galaxy, or M83, as seen in ultraviolet light (right) and at both ultraviolet and radio wavelengths (left). While the radio data highlight the galaxy's long, octopus-like arms stretching far beyond its main spiral disk (red), the ultraviolet data reveal clusters of baby stars (blue) within the extended arms. The ultraviolet image was taken by NASA's Galaxy Evolution Explorer between March 15 and May 20, 2007, at scheduled intervals. Back in 2005, the telescope first photographed M83 over a shorter period of time. That picture was the first to reveal far-flung baby stars forming up to 63,000 light-years from the edge of the main spiral disk. This came as a surprise to astronomers because a galaxy's outer territory typically lacks high densities of star-forming materials. The newest picture of M83 from the Galaxy Evolution Explorer is shown at the right, and was taken over a longer period of time. In fact, it is one of the

  15. Galactic Astronomy in the Ultraviolet

    Science.gov (United States)

    Rastorguev, A. S.; Sachkov, M. E.; Zabolotskikh, M. V.

    2017-12-01

    We propose a number of prospective observational programs for the ultraviolet space observatory WSO-UV, which seem to be of great importance to modern galactic astronomy. The programs include the search for binary Cepheids; the search and detailed photometric study and the analysis of radial distribution of UV-bright stars in globular clusters ("blue stragglers", blue horizontal-branch stars, RR Lyrae variables, white dwarfs, and stars with UV excesses); the investigation of stellar content and kinematics of young open clusters and associations; the study of spectral energy distribution in hot stars, including calculation of the extinction curves in the UV, optical and NIR; and accurate definition of the relations between the UV-colors and effective temperature. The high angular resolution of the observatory allows accurate astrometric measurements of stellar proper motions and their kinematic analysis.

  16. Photosynthetic carbon reduction by seagrasses exposed to ultraviolet A radiation

    Science.gov (United States)

    1979-01-01

    The seagrasses Halophila engelmannii, Halodule wrightii, and Syringodium filiforme were examined for their intrinsic sensitivity to ultraviolet-A-UV-A and ultraviolet-B-UV-B radiation. The effect of UV-A on photosynthetically active radiation (PAR) was also determined. Ultraviolet-A and ultraviolet-B were studied with emphasis on the greater respective environmental consequence in terms of seagrass distribution and abundance. Results indicate that an intrinsic sensitivity to UV-A alone is apparent only in Halophila, while net photosynthesis in Halodule and Syringodium seems unaffected by the level of UV-A provided. The sensitivity of Halophila to UV-A in the absense of (PAR) indicates that the photosynthetic reaction does not need to be in operation for damage to occur. Other significant results are reported.

  17. 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.

  18. Ultraviolet sterilization

    International Nuclear Information System (INIS)

    Schenck, G.O.

    1987-01-01

    Artificial ultraviolet radiation sources can supply bactericidal energy in such a high dosage that in less than a second a higher degree of disinfection is accomplished than by sun irradiation in hours. Bacteria, viruses, phages, and organic micropollutants can be degraded by photochemical wet combustion down to and below detection limits of organic carbon. There are no known ultraviolet-resistant microorganisms. There are limitations to ultraviolet treatment which can often be overcome by adequate technical measures. Unlike other water purification processes, ultraviolet irradiation only exterminates living organisms. The radiation must be able to penetrate to the objects of the kill; in a dose large enough to kill, and long enough to kill and prevent new growth. Contrary to filters, ultraviolet flow-through reactors do not restrict free flow significantly. In contrast to distillation, ultraviolet irradiation imposes no phase changes to the water. Used as a sequence in ultrapure water systems, maintenance requirements are virtually nonexistent; because of the absence of dissolved and particulate matter in purified water, mechanical cleaning of the photoreactor chambers is not essential. The process is highly economical; energy consumption is low and supervision minimal. 103 refs., 45 figs., 15 tabs

  19. Modeling ground-based timber harvesting systems using computer simulation

    Science.gov (United States)

    Jingxin Wang; Chris B. LeDoux

    2001-01-01

    Modeling ground-based timber harvesting systems with an object-oriented methodology was investigated. Object-oriented modeling and design promote a better understanding of requirements, cleaner designs, and better maintainability of the harvesting simulation system. The model developed simulates chainsaw felling, drive-to-tree feller-buncher, swing-to-tree single-grip...

  20. The COROT ground-based archive and access system

    Science.gov (United States)

    Solano, E.; González-Riestra, R.; Catala, C.; Baglin, A.

    2002-01-01

    A prototype of the COROT ground-based archive and access system is presented here. The system has been developed at LAEFF and it is based on the experience gained at Laboratorio de Astrofisica Espacial y Fisica Fundamental (LAEFF) with the INES (IUE Newly Extracted System) Archive.

  1. Mean Annual UV-B Irradiance

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ultraviolet-B (UV-B) radiation is the most energetic part of sunlight reaching the Earth's surface (wavelength region is 280 to 315 nm), and it has been shown to...

  2. Mutagenesis of Trichoderma Viride by Ultraviolet and Plasma

    International Nuclear Information System (INIS)

    Yao Risheng; Li Manman; Deng Shengsong; Hu Huajia; Wang Huai; Li Fenghe

    2012-01-01

    Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet (UV) and plasma mutation. The mutant produced a 21.0 IU/mL FPase which was 98.1% higher than that of the parent strain Trichoderma viride ZY-1. In addition, the effect of ultraviolet and plasma mutagenesis was not merely simple superimposition of single ultraviolet mutation and single plasma mutation. Meanwhile, there appeared a capsule around some of the spores after the ultraviolet and plasma treatment, namely, the spore surface of the strain became fuzzy after ultraviolet or ultraviolet and plasma mutagenesis.

  3. Mutagenesis of Trichoderma Viride by Ultraviolet and Plasma

    Science.gov (United States)

    Yao, Risheng; Li, Manman; Deng, Shengsong; Hu, Huajia; Wang, Huai; Li, Fenghe

    2012-04-01

    Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet (UV) and plasma mutation. The mutant produced a 21.0 IU/mL FPase which was 98.1% higher than that of the parent strain Trichoderma viride ZY-1. In addition, the effect of ultraviolet and plasma mutagenesis was not merely simple superimposition of single ultraviolet mutation and single plasma mutation. Meanwhile, there appeared a capsule around some of the spores after the ultraviolet and plasma treatment, namely, the spore surface of the strain became fuzzy after ultraviolet or ultraviolet and plasma mutagenesis.

  4. Solar ultraviolet irradiance variations: a review

    International Nuclear Information System (INIS)

    Lean, J.

    1987-01-01

    Despite the geophysical importance of solar ultraviolet radiation, specific aspects of its temporal variations have not yet been adequately determined experimentally, nor are the mechanisms for the variability completely understood. Satellite observations have verified the reality of solar ultraviolet irradiance variations over time scales of days and months, and model calculations have confirmed the association of these short-term variations with the evolution and rotation of regions of enhanced magnetic activity on the solar disc. However, neither rocket nor satellite measurements have yet been made with sufficient accuracy and regularity to establish unequivocally the nature of the variability over the longer time of the 11-year solar cycle. The comparative importance for the long-term variations of local regions of enhanced magnetic activity and global scale activity perturbations is still being investigated. Solar ultraviolet irradiance variations over both short and long time scales are reviewed, with emphasis on their connection to solar magnetic activity. Correlations with ground-based measures of solar variability are examined because of the importance of the ground-based observations as historical proxies of ultraviolet irradiance variations. Current problems in understanding solar ultraviolet irradiance variations are discussed, and the measurements planned for solar cycle 22, which may resolve these problems, are briefly described. copyright American Geophysical Union 1987

  5. Ultraviolet reflectance by the cere of raptors

    Science.gov (United States)

    Mougeot, François; Arroyo, Beatriz E

    2006-01-01

    Ultraviolet (UV) signals have been shown to play key roles in social and sexual signalling in birds. Using a spectrophotometer, we analysed the colour of the cere (skin above the beak) of a diurnal raptor, the Montagu's harrier (Circus pygargus), and show that it reflects in the UV part of the spectrum. The cere is a well-known sexual signal in raptors, with carotenoid based pigmentation being indicative of quality. We thus hypothesized that UV reflectance also signals quality. Accordingly, we found that in our sample of wild males, the location of the UV peak was related to the orangeness of cere and correlated with male body mass and condition (mass corrected for size). Also, males with brighter UV were mated to females that laid earlier, as expected if UV reflectance relates to a male's quality and attractiveness. Future studies should investigate the relationships between UV reflectance and carotenoid pigmentation of cere, and test how UV reflectance influences mate choice. PMID:17148356

  6. Formation dynamics of UV and EUV induced hydrogen plasma

    NARCIS (Netherlands)

    Dolgov, A.A.; Lee, Christopher James; Yakushev, O.; Lopaev, D.V.; Abrikosov, A.; Krivtsun, V.M.; Zotovich, A.; Bijkerk, F.

    2014-01-01

    The comparative study of the dynamics of ultraviolet (UV) and extreme ultraviolet (EUV) induced hydrogen plasma was performed. It was shown that for low H2 pressures and bias voltages, the dynamics of the two plasmas are significantly different. In the case of UV radiation, the plasma above the

  7. HST/STIS ULTRAVIOLET SPECTROSCOPY OF THE COMPONENTS OF THE MASSIVE TRIPLE STAR δ ORI A

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Noel D.; Moffat, Anthony F. J. [Département de physique and Centre de Recherche en Astrophysique du Québec (CRAQ), Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7 (Canada); Gull, Theodore R.; Lindler, Don J. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gies, Douglas R. [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States); Corcoran, Michael F. [CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD 20771 (United States); Chené, André-Nicolas, E-mail: richardson@astro.umontreal.ca, E-mail: moffat@astro.umontreal.ca, E-mail: theodore.r.gull@nasa.gov, E-mail: don.j.lindler@nasa.gov, E-mail: gies@chara.gsu.edu, E-mail: michael.f.corcoran@nasa.gov, E-mail: achene@gemini.edu [Gemini Observatory, Northern Operations Center, 670 North A’ohoku Place, Hilo, HI 96720 (United States)

    2015-07-20

    The multiple star system of δ Orionis is one of the closest examples of a system containing a luminous O-type, bright giant star (component Aa1). It is often used as a spectral-type standard and has the highest observed X-ray flux of any hot-star binary. The main component Aa1 is orbited by two lower mass stars, faint Aa2 in a 5.7 day eclipsing binary, and Ab, an astrometric companion with an estimated period of 346 years. Generally the flux from all three stars is recorded in ground-based spectroscopy, and the spectral decomposition of the components has proved difficult. Here we present Hubble Space Telescope/Space Telescope Imaging Spectrograph ultraviolet spectroscopy of δ Ori A that provides us with spatially separated spectra of Aa and Ab for the first time. We measured radial velocities for Aa1 and Ab in two observations made near the velocity extrema of Aa1. We show tentative evidence for the detection of the Aa2 component in cross-correlation functions of the observed and model spectra. We discuss the appearance of the UV spectra of Aa1 and Ab with reference to model spectra. Both stars have similar effective temperatures, but Ab is fainter and is a rapid rotator. The results will help in the interpretation of ground-based spectroscopy and in understanding the physical and evolutionary parameters of these massive stars.

  8. Photoprotective Effect of Tea and its Extracts against Ultraviolet ...

    African Journals Online (AJOL)

    Ultraviolet (UV) exposure induces photodamage of skin. It is a matter of concern that the level of UV radiation reaching the earth surface is increasing as a result of depletion of the stratospheric ozone, and climate change. It is urgently necessary to develop strategies to protect the skin from UV-induced injuries. Tea extracts ...

  9. Effect of ultraviolet-B radiation on biochemical and antioxidant ...

    African Journals Online (AJOL)

    user

    The stratospheric ozone depletion and enhanced solar ultraviolet-B (UV-B) ... mechanism produced by enzymatic antioxidant such as catalase, peroxidase, ... absorb UV-B and prevent it from penetrating into the leaf mosophyll cells. The aim of this work was to investigate the effects of UV-B radiation on Indigofera tinctoria ...

  10. Space situational awareness satellites and ground based radiation counting and imaging detector technology

    International Nuclear Information System (INIS)

    Jansen, Frank; Behrens, Joerg; Pospisil, Stanislav; Kudela, Karel

    2011-01-01

    We review the current status from the scientific and technological point of view of solar energetic particles, solar and galactic cosmic ray measurements as well as high energy UV-, X- and gamma-ray imaging of the Sun. These particles and electromagnetic data are an important tool for space situational awareness (SSA) aspects like space weather storm predictions to avoid failures in space, air and ground based technological systems. Real time data acquisition, position and energy sensitive imaging are demanded by the international space weather forecast services. We present how newly developed, highly miniaturized radiation detectors can find application in space in view of future SSA related satellites as a novel space application due to their counting and imaging capabilities.

  11. Space situational awareness satellites and ground based radiation counting and imaging detector technology

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Frank, E-mail: frank.jansen@dlr.de [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Behrens, Joerg [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Pospisil, Stanislav [Czech Technical University, IEAP, 12800 Prague 2, Horska 3a/22 (Czech Republic); Kudela, Karel [Slovak Academy of Sciences, IEP, 04001 Kosice, Watsonova 47 (Slovakia)

    2011-05-15

    We review the current status from the scientific and technological point of view of solar energetic particles, solar and galactic cosmic ray measurements as well as high energy UV-, X- and gamma-ray imaging of the Sun. These particles and electromagnetic data are an important tool for space situational awareness (SSA) aspects like space weather storm predictions to avoid failures in space, air and ground based technological systems. Real time data acquisition, position and energy sensitive imaging are demanded by the international space weather forecast services. We present how newly developed, highly miniaturized radiation detectors can find application in space in view of future SSA related satellites as a novel space application due to their counting and imaging capabilities.

  12. Structural characterization of native high-methoxylated pectin using nuclear magnetic resonance spectroscopy and ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Comparative use of 2,5-dihydroxybenzoic acid and nor-harmane as UV-MALDI matrices.

    Science.gov (United States)

    Monge, María Eugenia; Negri, R Martín; Kolender, Adriana A; Erra-Balsells, Rosa

    2007-01-01

    The successful analysis by ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (UV-MALDI-TOF MS) of native and hydrolyzed high-methoxylated pectin samples is described. In order to find the optimal conditions for UV-MALDI-TOF MS analysis several experimental variables were studied such as: different UV-MALDI matrices (nor-harmane, 2,5-dihydroxybenzoic acid), sample preparation methods (mixture, sandwich), inorganic salt addition (doping salts, NaCl, KCl, NH(4)Cl), ion mode (positive, negative), linear and reflectron mode, etc. nor-Harmane has never been used as a UV-MALDI matrix for the analysis of pectins but its use avoids pre-treatment of the sample, such as an enzymatic digestion or an acid hydrolysis, and there is no need to add salts, making the analysis easier and faster. This study suggested an alternative way of analyzing native high-methoxylated pectins, with UV-MALDI-TOF MS, by using nor-harmane as the matrix in negative ion mode. The analysis by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy of the native and hydrolyzed pectin is also briefly described. Copyright (c) 2007 John Wiley & Sons, Ltd.

  13. ULTRAVIOLET HALOS AROUND SPIRAL GALAXIES. I. MORPHOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Hodges-Kluck, Edmund; Cafmeyer, Julian; Bregman, Joel N., E-mail: hodgeskl@umich.edu [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-12-10

    We examine ultraviolet halos around a sample of highly inclined galaxies within 25 Mpc to measure their morphology and luminosity. Despite contamination from galactic light scattered into the wings of the point-spread function, we find that ultraviolet (UV) halos occur around each galaxy in our sample. Around most galaxies the halos form a thick, diffuse disk-like structure, but starburst galaxies with galactic superwinds have qualitatively different halos that are more extensive and have filamentary structure. The spatial coincidence of the UV halos above star-forming regions, the lack of consistent association with outflows or extraplanar ionized gas, and the strong correlation between the halo and galaxy UV luminosity suggest that the UV light is an extragalactic reflection nebula. UV halos may thus represent 10{sup 6}–10{sup 7} M {sub ⊙} of dust within 2–10 kpc of the disk, whose properties may change with height in starburst galaxies.

  14. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

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

  15. [Effect of Charge-Transfer Complex on Ultraviolet-Visible (UV-Vis) Absorption Property of Chromophoric Dissolved Organic Matter (CDOM) in Waters of Typical Water-Level Fluctuation Zones of the Three Gorges Reservoir Areas].

    Science.gov (United States)

    Jiang, Tao; Liang, Jian; Zhang, Mu-xue; Wang, Ding-yong; Wei, Shi-qiang; Lu, Song

    2016-02-15

    As an important fraction of dissolved organic matter (DOM), chromophoric dissolved organic matter (CDOM) plays a key role in decision of the optical properties and photogeochemistry of DOM, and further affects pollutant fate and global carbon cycle. These optical properties are ascribed to two chromophoric systems including superposition of individual chromophores and charge-transfer (CT) complexation between electron donor (e.g., phenols and indoles) and acceptor (e.g., quinones and other oxidized aromatics) in DOM structures. Thus in this study, based on the "double-chromophoric system" model, DOM samples from four typical water-level fluctuation zones of Three Gorges Reservoir (TGR) areas were selected, to investigate the effect and contribution of charge-transfer complex to ultraviolet-visible (UV-Vis) absorption property of CDOM. Using NaBH, reduction method, original featureless absorption curve was classified into two independent curves caused by individual chromophoric group, which were derived from a simple superposition of independent chromophore and charge-transfer complex, respectively. Also, the changes in curve properties and specific parameters before and after NaBH4 reduction were compared. The results showed that in all DOM samples from the four sites of TGR, more than 35% of absorption was attributed from CT complex. Shibaozhai of Zhongxian and Zhenxi of Fuling showed the highest proportion ( > 50%). It suggested that the role of CT complex in CDOM property could not be neglected. After removal of CT complex, absorption curve showed blue-shift and CDOM concentration [a (355)] decreased significantly. Meanwhile, because of deforming of bonds by reduction, DOM structures became more dispersive and the molecular size was decreased, resulting in the lower spectral slope (S) observed, which evidentially supported that the supermolecular association structure of DOM was self-assembled through CT complex. Meanwhile, deceasing hydrophobic components led

  16. High energy astrophysics with ground-based gamma ray detectors

    International Nuclear Information System (INIS)

    Aharonian, F; Buckley, J; Kifune, T; Sinnis, G

    2008-01-01

    Recent advances in ground-based gamma ray astronomy have led to the discovery of more than 70 sources of very high energy (E γ ≥ 100 GeV) gamma rays, falling into a number of source populations including pulsar wind nebulae, shell type supernova remnants, Wolf-Rayet stars, giant molecular clouds, binary systems, the Galactic Center, active galactic nuclei and 'dark' (yet unidentified) galactic objects. We summarize the history of TeV gamma ray astronomy up to the current status of the field including a description of experimental techniques and highlight recent astrophysical results. We also discuss the potential of ground-based gamma ray astronomy for future discoveries and describe possible directions for future instrumental developments

  17. Ground-based Nuclear Detonation Detection (GNDD) Technology Roadmap

    International Nuclear Information System (INIS)

    Casey, Leslie A.

    2014-01-01

    This GNDD Technology Roadmap is intended to provide guidance to potential researchers and help management define research priorities to achieve technology advancements for ground-based nuclear explosion monitoring science being pursued by the Ground-based Nuclear Detonation Detection (GNDD) Team within the Office of Nuclear Detonation Detection in the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE). Four science-based elements were selected to encompass the entire scope of nuclear monitoring research and development (R&D) necessary to facilitate breakthrough scientific results, as well as deliver impactful products. Promising future R&D is delineated including dual use associated with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Important research themes as well as associated metrics are identified along with a progression of accomplishments, represented by a selected bibliography, that are precursors to major improvements to nuclear explosion monitoring.

  18. Ground-based Nuclear Detonation Detection (GNDD) Technology Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Leslie A.

    2014-01-13

    This GNDD Technology Roadmap is intended to provide guidance to potential researchers and help management define research priorities to achieve technology advancements for ground-based nuclear explosion monitoring science being pursued by the Ground-based Nuclear Detonation Detection (GNDD) Team within the Office of Nuclear Detonation Detection in the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE). Four science-based elements were selected to encompass the entire scope of nuclear monitoring research and development (R&D) necessary to facilitate breakthrough scientific results, as well as deliver impactful products. Promising future R&D is delineated including dual use associated with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Important research themes as well as associated metrics are identified along with a progression of accomplishments, represented by a selected bibliography, that are precursors to major improvements to nuclear explosion monitoring.

  19. Threat of ultraviolet radiation to the eye--how to protect against it

    International Nuclear Information System (INIS)

    Pitts, D.G.

    1981-01-01

    The purpose of this paper is to discuss the effects of exposure of the eye to ultraviolet (UV) radiation and to provide information from which protective criteria and standards may be established. To accomplish this purpose, the article discusses ultraviolet radiation, absorption of UV radiation by the eye, the effects of ocular exposure to ultraviolet radiation, and how to protect the eye against exposure to UV radiation

  20. Automatic Barometric Updates from Ground-Based Navigational Aids

    Science.gov (United States)

    1990-03-12

    ro fAutomatic Barometric Updates US Department from of Transportation Ground-Based Federal Aviation Administration Navigational Aids Office of Safety...tighter vertical spacing controls , particularly for operations near Terminal Control Areas (TCAs), Airport Radar Service Areas (ARSAs), military climb and...E.F., Ruth, J.C., and Williges, B.H. (1987). Speech Controls and Displays. In Salvendy, G., E. Handbook of Human Factors/Ergonomics, New York, John

  1. Biomass burning aerosols characterization from ground based and profiling measurements

    Science.gov (United States)

    Marin, Cristina; Vasilescu, Jeni; Marmureanu, Luminita; Ene, Dragos; Preda, Liliana; Mihailescu, Mona

    2018-04-01

    The study goal is to assess the chemical and optical properties of aerosols present in the lofted layers and at the ground. The biomass burning aerosols were evaluated in low level layers from multi-wavelength lidar measurements, while chemical composition at ground was assessed using an Aerosol Chemical Speciation Monitor (ACSM) and an Aethalometer. Classification of aerosol type and specific organic markers were used to explore the potential to sense the particles from the same origin at ground base and on profiles.

  2. Silicon carbide optics for space and ground based astronomical telescopes

    Science.gov (United States)

    Robichaud, Joseph; Sampath, Deepak; Wainer, Chris; Schwartz, Jay; Peton, Craig; Mix, Steve; Heller, Court

    2012-09-01

    Silicon Carbide (SiC) optical materials are being applied widely for both space based and ground based optical telescopes. The material provides a superior weight to stiffness ratio, which is an important metric for the design and fabrication of lightweight space telescopes. The material also has superior thermal properties with a low coefficient of thermal expansion, and a high thermal conductivity. The thermal properties advantages are important for both space based and ground based systems, which typically need to operate under stressing thermal conditions. The paper will review L-3 Integrated Optical Systems - SSG’s (L-3 SSG) work in developing SiC optics and SiC optical systems for astronomical observing systems. L-3 SSG has been fielding SiC optical components and systems for over 25 years. Space systems described will emphasize the recently launched Long Range Reconnaissance Imager (LORRI) developed for JHU-APL and NASA-GSFC. Review of ground based applications of SiC will include supporting L-3 IOS-Brashear’s current contract to provide the 0.65 meter diameter, aspheric SiC secondary mirror for the Advanced Technology Solar Telescope (ATST).

  3. HUBBLE SPACE TELESCOPE AND GROUND-BASED OBSERVATIONS OF V455 ANDROMEDAE POST-OUTBURST

    Energy Technology Data Exchange (ETDEWEB)

    Szkody, Paula; Mukadam, Anjum S.; Brown, Justin; Funkhouser, Kelsey [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Gänsicke, Boris T. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Henden, Arne [AAVSO, 49 Bay State Road, Cambridge, MA 02138 (United States); Sion, Edward M. [Department of Astronomy and Astrophysics, Villanova University, Villanova, PA 19085 (United States); Townsley, Dean M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Christian, Damian [Department of Physics and Astronomy, California State University, Northridge, CA 91330 (United States); Falcon, Ross E. [Department of Astronomy, University of Texas, Austin, TX 78712 (United States); Pyrzas, Stylianos, E-mail: szkody@astro.washington.edu, E-mail: anjum@astro.washington.edu, E-mail: boris.gaensicke@warwick.ac.uk, E-mail: arne@aavso.org, E-mail: edward.sion@villanova.edu, E-mail: Dean.M.Townsley@ua.edu, E-mail: damian.christian@csun.edu, E-mail: cylver@astro.as.utexas.edu, E-mail: stylianos.pyrzas@gmail.com [Instituto de Astronomia, Universidad Catolica del Norte, Avenida Angamos 0619, Antofagasta (Chile)

    2013-09-20

    Hubble Space Telescope spectra obtained in 2010 and 2011, 3 and 4 yr after the large amplitude dwarf nova outburst of V455 And, were combined with optical photometry and spectra to study the cooling of the white dwarf, its spin, and possible pulsation periods after the outburst. The modeling of the ultraviolet (UV) spectra shows that the white dwarf temperature remains ∼600 K hotter than its quiescent value at 3 yr post-outburst, and still a few hundred degrees hotter at 4 yr post-outburst. The white dwarf spin at 67.6 s and its second harmonic at 33.8 s are visible in the optical within a month of outburst and are obvious in the later UV observations in the shortest wavelength continuum and the UV emission lines, indicating an origin in high-temperature regions near the accretion curtains. The UV light curves folded on the spin period show a double-humped modulation consistent with two-pole accretion. The optical photometry 2 yr after outburst shows a group of frequencies present at shorter periods (250-263 s) than the periods ascribed to pulsation at quiescence, and these gradually shift toward the quiescent frequencies (300-360 s) as time progresses past outburst. The most surprising result is that the frequencies near this period in the UV data are only prominent in the emission lines, not the UV continuum, implying an origin away from the white dwarf photosphere. Thus, the connection of this group of periods with non-radial pulsations of the white dwarf remains elusive.

  4. Ultraviolet - status of knowledge on exposure and health risks

    International Nuclear Information System (INIS)

    Dervault, Anne Marie; Secretan, Beatrice; Guinot, Christiane; Bazex, Jacques; Donadieu, Jean; Dore, Jean Francois; Cesarini, Jean Pierre; Aleth Richard, Marie; Leccia, Marie Therese; Autier, Philippe; Cesarini, Jean Pierre; Beani, Jean Claude; Grob, Jean Jacques; Wald, Lucien; Dore, Jean Francois; Casiniere, Alain de la; Dixsaut, Gilles; Guenel, Pascal; Choulika, Sophie; Pirard, Philippe; Bastuji-Garin, S.; Beani, J.C.; Brin, A.J.; Cadet, J.; Corre, M.F.; Frelon, J.H.; Grob, Jean Jacques; Jeanmougin, M.; Martini-Morel, M.C.; Meunier, L.; Marty, J.P.; Revuz, J.; Reynier, J.P.; Roelands, R.; Stoebner, A.; Vian, L.

    2005-05-01

    After having recalled some physical aspects of ultraviolet radiations (presence in solar radiation, artificial UV radiation, measurement, metrology, UV index, boundary limits), this report describes the biological and health effects of UV radiations (analysis methodology, recall of previous expert reports, biological effects, health effects), addresses human behaviour with respect to UV radiation and exposure to UV radiation, discusses the relationship between cosmetics and UV radiation. It presents the various European and international positions with respect to UV emitting devices (evolution of standards, regulations). Some recommendations are made regarding solar exposure, sun-tanning installations, and other domestic or industrial sources

  5. Ultraviolet vision in birds: the importance of transparent eye media

    OpenAIRE

    Lind, Olle; Mitkus, Mindaugas; Olsson, Peter; Kelber, Almut

    2014-01-01

    Ultraviolet (UV)-sensitive visual pigments are widespread in the animal kingdom but many animals, for example primates, block UV light from reaching their retina by pigmented lenses. Birds have UV-sensitive (UVS) visual pigments with sensitivity maxima around 360–373 nm (UVS) or 402–426 nm (violet-sensitive, VS). We describe how these pigments are matched by the ocular media transmittance in 38 bird species. Birds with UVS pigments have ocular media that transmit more UV light (wavelength of ...

  6. Improving Assessment of Lifetime Solar Ultraviolet Radiation Exposure in Epidemiologic Studies: Comparison of Ultraviolet Exposure Assessment Methods in a Nationwide United States Occupational Cohort.

    Science.gov (United States)

    Little, Mark P; Tatalovich, Zaria; Linet, Martha S; Fang, Michelle; Kendall, Gerald M; Kimlin, Michael G

    2018-06-13

    Solar ultraviolet radiation is the primary risk factor for skin cancers and sun-related eye disorders. Estimates of individual ambient ultraviolet irradiance derived from ground-based solar measurements and from satellite measurements have rarely been compared. Using self-reported residential history from 67,189 persons in a nationwide occupational US radiologic technologists cohort, we estimated ambient solar irradiance using data from ground-based meters and noontime satellite measurements. The mean distance-moved from city of longest residence in childhood increased from 137.6 km at ages 13-19 to 870.3 km at ages ≥65, with corresponding increases in absolute latitude-difference moved. At ages 20/40/60/80, the Pearson/Spearman correlation coefficients of ground-based and satellite-derived solar potential ultraviolet exposure, using irradiance and cumulative radiant-exposure metrics, were high (=0.87-0.92). There was also moderate correlation (Pearson/Spearman correlation coefficients=0.51-0.60) between irradiance at birth and at last-known address, for ground-based and satellite data. Satellite-based lifetime estimates of ultraviolet radiation were generally 14-15% lower than ground-based estimates, albeit with substantial uncertainties, possibly because ground-based estimates incorporate fluctuations in cloud and ozone, which are incompletely incorporated in the single noontime satellite-overpass ultraviolet value. If confirmed elsewhere, the findings suggest that ground-based estimates may improve exposure-assessment accuracy and potentially provide new insights into ultraviolet-radiation-disease relationships in epidemiologic studies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Ultraviolet radiation and cyanobacteria.

    Science.gov (United States)

    Rastogi, Rajesh Prasad; Sinha, Rajeshwar P; Moh, Sang Hyun; Lee, Taek Kyun; Kottuparambil, Sreejith; Kim, Youn-Jung; Rhee, Jae-Sung; Choi, Eun-Mi; Brown, Murray T; Häder, Donat-Peter; Han, Taejun

    2014-12-01

    Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Ultraviolet Radiations: Skin Defense-Damage Mechanism.

    Science.gov (United States)

    Mohania, Dheeraj; Chandel, Shikha; Kumar, Parveen; Verma, Vivek; Digvijay, Kumar; Tripathi, Deepika; Choudhury, Khushboo; Mitten, Sandeep Kumar; Shah, Dilip

    2017-01-01

    UV-radiations are the invisible part of light spectra having a wavelength between visible rays and X-rays. Based on wavelength, UV rays are subdivided into UV-A (320-400 nm), UV-B (280-320 nm) and UV-C (200-280 nm). Ultraviolet rays can have both harmful and beneficial effects. UV-C has the property of ionization thus acting as a strong mutagen, which can cause immune-mediated disease and cancer in adverse cases. Numbers of genetic factors have been identified in human involved in inducing skin cancer from UV-radiations. Certain heredity diseases have been found susceptible to UV-induced skin cancer. UV radiations activate the cutaneous immune system, which led to an inflammatory response by different mechanisms. The first line of defense mechanism against UV radiation is melanin (an epidermal pigment), and UV absorbing pigment of skin, which dissipate UV radiation as heat. Cell surface death receptor (e.g. Fas) of keratinocytes responds to UV-induced injury and elicits apoptosis to avoid malignant transformation. In addition to the formation of photo-dimers in the genome, UV also can induce mutation by generating ROS and nucleotides are highly susceptible to these free radical injuries. Melanocortin 1 receptor (MC1R) has been known to be implicated in different UV-induced damages such as pigmentation, adaptive tanning, and skin cancer. UV-B induces the formation of pre-vitamin D3 in the epidermal layer of skin. UV-induced tans act as a photoprotection by providing a sun protection factor (SPF) of 3-4 and epidermal hyperplasia. There is a need to prevent the harmful effects and harness the useful effects of UV radiations.

  9. UV-induced skin damage

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  10. Impacts of Brown Carbon from Biomass Burning on Surface UV and Ozone Photochemistry in the Amazon Basin

    Science.gov (United States)

    Mok, Jungbin; Krotkov, Nickolay A.; Arola, Antti; Torres, Omar; Jethva, Hiren; Andrade, Marcos; Labow, Gordon; Eck, Thomas F.; Li, Zhangqing; Dickerson, Russell R.; hide

    2016-01-01

    The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or brown carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths. Using the ground-based inversion of column effective imaginary refractive index in the range 305368nm, we quantified a strong spectral dependence of absorption by BrC in the UV and diminished ultraviolet B (UV-B) radiation reaching the surface. Reduced UV-B means less erythema, plant damage, and slower photolysis rates. We use a photochemical box model to show that relative to black carbon (BC) alone, the combined optical properties of BrC and BC slow the net rate of production of ozone by up to 18 and lead to reduced concentrations of radicals OH, HO2, and RO2 by up to 17, 15, and 14, respectively. The optical properties of BrC aerosol change in subtle ways the generally adverse effects of smoke from biomass burning.

  11. Impacts of brown carbon from biomass burning on surface UV and ozone photochemistry in the Amazon Basin

    KAUST Repository

    Mok, Jungbin

    2016-11-11

    The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or “brown” carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths. Using the ground-based inversion of column effective imaginary refractive index in the range 305–368 nm, we quantified a strong spectral dependence of absorption by BrC in the UV and diminished ultraviolet B (UV-B) radiation reaching the surface. Reduced UV-B means less erythema, plant damage, and slower photolysis rates. We use a photochemical box model to show that relative to black carbon (BC) alone, the combined optical properties of BrC and BC slow the net rate of production of ozone by up to 18% and lead to reduced concentrations of radicals OH, HO2, and RO2 by up to 17%, 15%, and 14%, respectively. The optical properties of BrC aerosol change in subtle ways the generally adverse effects of smoke from biomass burning.

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

    International Nuclear Information System (INIS)

    Gogosheva, Tz.; Petkov, B.; Mendeva, B.; Krastev, D.

    2003-01-01

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

  13. Ultraviolet radiation response of two heterotropy Antarctic marine bacterial

    International Nuclear Information System (INIS)

    Hernandez, Edgardo A.; Ferreyra, Gustavo A.; Mac Cormack, Walter P.

    2004-01-01

    Two Antarctic marine bacterial strains, were exposed to different irradiance of ultraviolet (UV) solar radiation using several experimental protocols and interferential filters. Results showed that both, UV-A and UV-B radiation produce deleterious effects on two tested bacterial strains. The mortality values under UVB treatments were higher than those observed under UVA treatments. UVvi strain proved to be more resistant to UV radiation than the UVps strain. (author) [es

  14. Validation of OMI erythemal doses with multi-sensor ground-based measurements in Thessaloniki, Greece

    Science.gov (United States)

    Zempila, Melina Maria; Fountoulakis, Ilias; Taylor, Michael; Kazadzis, Stelios; Arola, Antti; Koukouli, Maria Elissavet; Bais, Alkiviadis; Meleti, Chariklia; Balis, Dimitrios

    2018-06-01

    The aim of this study is to validate the Ozone Monitoring Instrument (OMI) erythemal dose rates using ground-based measurements in Thessaloniki, Greece. In the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, a Yankee Environmental System UVB-1 radiometer measures the erythemal dose rates every minute, and a Norsk Institutt for Luftforskning (NILU) multi-filter radiometer provides multi-filter based irradiances that were used to derive erythemal dose rates for the period 2005-2014. Both these datasets were independently validated against collocated UV irradiance spectra from a Brewer MkIII spectrophotometer. Cloud detection was performed based on measurements of the global horizontal radiation from a Kipp & Zonen pyranometer and from NILU measurements in the visible range. The satellite versus ground observation validation was performed taking into account the effect of temporal averaging, limitations related to OMI quality control criteria, cloud conditions, the solar zenith angle and atmospheric aerosol loading. Aerosol optical depth was also retrieved using a collocated CIMEL sunphotometer in order to assess its impact on the comparisons. The effect of total ozone columns satellite versus ground-based differences on the erythemal dose comparisons was also investigated. Since most of the public awareness alerts are based on UV Index (UVI) classifications, an analysis and assessment of OMI capability for retrieving UVIs was also performed. An overestimation of the OMI erythemal product by 3-6% and 4-8% with respect to ground measurements is observed when examining overpass and noontime estimates respectively. The comparisons revealed a relatively small solar zenith angle dependence, with the OMI data showing a slight dependence on aerosol load, especially at high aerosol optical depth values. A mean underestimation of 2% in OMI total ozone columns under cloud-free conditions was found to lead to an overestimation in OMI erythemal

  15. The ultraviolet variations of iota Cas

    Science.gov (United States)

    Molnar, M. R.; Mallama, A. D.; Soskey, D. G.; Holm, A. V.

    1976-01-01

    The Ap variable star iota Cas was observed with the photometers on OAO-2 covering the spectral range 1430-4250 A. The ultraviolet light curves show a double wave with primary minimum and maximum at phase ? 0.00 and 0.35, respectively. Secondary minimum light is at phase ? 0.65 with secondary maximum at phase ? 0.85. The light curves longward of 3150 A vary in opposition to those shortward of this 'null region'. Ground-based coude spectra show that the Fe II and Cr II line strengths have a double-wave variation such that maximum strength occurs at minimum ultraviolet light. We suggest that the strong ultraviolet opacities due to photoionization and line blanketing by these metals may cause the observed photometric variations. We have also constructed an oblique-rotator model which shows iron and chromium lying in a great circle band rather than in circular spots.

  16. Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

    Science.gov (United States)

    Zhu, Wei; Gould, Andrew

    2016-06-01

    Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.

  17. 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.

  18. Lidar to lidar calibration of Ground-based Lidar

    DEFF Research Database (Denmark)

    Fernandez Garcia, Sergio; Courtney, Michael

    This report presents the result of the lidar to lidar calibration performed for ground-based lidar. Calibration is here understood as the establishment of a relation between the reference lidar wind speed measurements with measurement uncertainties provided by measurement standard and corresponding...... lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from the reference lidar measurements are given for information only....

  19. A private ultraviolet channel in visual communication.

    Science.gov (United States)

    Cummings, Molly E; Rosenthal, Gil G; Ryan, Michael J

    2003-01-01

    Although private communication is considered an important diversifying force in evolution, there is little direct behavioural evidence to support this notion. Here, we show that ultraviolet (UV) signalling in northern swordtails (Xiphophorus) affords a channel for communication that is not accessible to their major predator, Astyanax mexicanus, the Mexican tetra. Laboratory and field behavioural experiments with swordtails (X. nigrensis) and predators (A. mexicanus) demonstrate that male UV ornamentation significantly increases their attractiveness to females but not to this predator, which is less sensitive to UV. UV reflectance among swordtail species correlates positively with tetra densities across habitats, and visual contrast estimates suggest that UV signals are highly conspicuous to swordtails in their natural environment. Cross-species comparisons also support the hypothesis that natural selection drives the use of UV communication. We compared two species, one with high (X. nigrensis) and one with low (X. malinche) Mexican tetra densities. Xiphophorus nigrensis males reflect significantly more UV than X. malinche, exhibit significant UV sexual dimorphism, and UV is a salient component of the sexual communication system. In X. malinche, however, males reflect minimally in the UV, there is no UV sexual dimorphism, and UV does not play a part in its communication system. PMID:12803903

  20. A private ultraviolet channel in visual communication.

    Science.gov (United States)

    Cummings, Molly E; Rosenthal, Gil G; Ryan, Michael J

    2003-05-07

    Although private communication is considered an important diversifying force in evolution, there is little direct behavioural evidence to support this notion. Here, we show that ultraviolet (UV) signalling in northern swordtails (Xiphophorus) affords a channel for communication that is not accessible to their major predator, Astyanax mexicanus, the Mexican tetra. Laboratory and field behavioural experiments with swordtails (X. nigrensis) and predators (A. mexicanus) demonstrate that male UV ornamentation significantly increases their attractiveness to females but not to this predator, which is less sensitive to UV. UV reflectance among swordtail species correlates positively with tetra densities across habitats, and visual contrast estimates suggest that UV signals are highly conspicuous to swordtails in their natural environment. Cross-species comparisons also support the hypothesis that natural selection drives the use of UV communication. We compared two species, one with high (X. nigrensis) and one with low (X. malinche) Mexican tetra densities. Xiphophorus nigrensis males reflect significantly more UV than X. malinche, exhibit significant UV sexual dimorphism, and UV is a salient component of the sexual communication system. In X. malinche, however, males reflect minimally in the UV, there is no UV sexual dimorphism, and UV does not play a part in its communication system.

  1. Photoprotective Effect of Tea and its Extracts against Ultraviolet ...

    African Journals Online (AJOL)

    Ultraviolet (UV) exposure induces photodamage of skin. It is a matter of ... to the skin as well as the photoprotective effects of tea and its extracts have been highlighted. ..... storage of skin cream supplemented with green tea catechins or EGCG ...

  2. Protective effect of (-)-epigallocatechin gallate on ultraviolet b ...

    African Journals Online (AJOL)

    Purpose: To investigate the protective effect of green tea (-)-epigallocatechin gallate (EGCg) on ultraviolet B (UV-B)-induced skin damages in hairless mice in order to develop a natural sunscreen ... hydrophilic cream has also showed high.

  3. High Data Rate Optical Wireless Communications Based on Ultraviolet Band

    KAUST Repository

    Sun, Xiaobin

    2017-01-01

    Optical wireless communication systems based on ultraviolet (UV)-band has a lot inherent advantages, such as low background solar radiation, low device dark noise. Besides, it also has small restrictive requirements for PAT (pointing, acquisition

  4. Responses of He-Ne laser on agronomic traits and the crosstalk between UVR8 signaling and phytochrome B signaling pathway in Arabidopsis thaliana subjected to supplementary ultraviolet-B (UV-B) stress.

    Science.gov (United States)

    Gao, Limei; Li, Yongfeng; Shen, Zhihua; Han, Rong

    2018-05-01

    UV-B acclimation effects and UV-B damage repair induced by a 632.8-nm He-Ne laser were investigated in Arabidopsis thaliana plants in response to supplementary UV-B stress. There was an increasing trend in growth parameters in the combination-treated plants with He-Ne laser and UV-B light compared to those stressed with enhanced UV-B light alone during different developmental stages of plants. The photosynthetic efficiency (Pn) and survival rates of seedlings were significantly higher in the combination treatments than UV-B stress alone. The expression of UVR8, phytochrome B (PhyB), and their mediated signal responsive genes such as COP1, HY5, and CHS were also significantly upregulated in plants with the laser irradiation compared with other groups without the laser. Levels of flavonol accumulation in leaves and capsule yield of He-Ne laser-treated plants were increased. The phyB-9 mutants were more sensitive to enhanced UV-B stress and had no obvious improvements in plant phenotypic development and physiological damage caused by enhanced UV-B stress after He-Ne laser irradiation. Our results suggested that UVR8 and its mediated signaling pathway via interaction with COP1 can be induced by He-Ne laser, and these processes were dependent on cytoplasmic PhyB levels in plant cells, which might be one of the most important mechanisms of He-Ne laser on UV-B protection and UV-B damage repair. These current data have also elucidated that the biostimulatory effects of He-Ne laser on Arabidopsis thaliana plants would happen not only during the early growth stage but also during the entire late developmental stage.

  5. Ultraviolet radiation

    International Nuclear Information System (INIS)

    Faber, M.

    1982-01-01

    Penetration of the human body by shorter-wavelength UV is restricted to the epidermis. Penetration is somewhat deeper at longer wavelengths and in non-pigmented subjects, where there is some penetration into the dermis, especially at wavelengths greater than 300 nm. The same is true for the eye. Most of the UV will be absorbed by the cornea. The lens and the tissues in the anterior part of the eye may, however, be exposed to UV at wavelengths above 295 nm. The final absorption takes place in the lens, and the retina can be exposed only under special circumstances. The penetration of different wavelengths into the eye is given in Table 1. Some doubt exists, however as to the high transmission given for the vitreous humour at the longer wavelengths. The absorption of UV depends on the wavelength. The absorption spectrum describes this relationship. Proteins and nucleic acids are the most important biological absorbers. Nucleic acids have their main absorption peak close to 265 nm, due to the pyrimidine structure. The aromatic amino-acids are the absorbing sites in protein, with tyrosine at 275 nm and tryptophane at 280 nm

  6. Ultraviolet radiation

    International Nuclear Information System (INIS)

    Faber, M.

    1989-01-01

    Although UV radiation can arise from a large number of man-made sources, the sun is the main source and both the general public and people working out of doors will be exposed to it. This natural background radiation and the variations in its magnitude must be taken into account when exposure limits are discussed. The full extent to which UV affects human well-being is difficult to quantify. Artificially produced UV has, however, been used in mines and cellars and in far northern latitudes as a supplement to combat functional impairment among people. Many of the observed effects, such as a decrease in the incidence of infectious diseases and in absenteeism, may be due to the bactericidal nature of the radiation. On the other hand, large doses of UV have an acute destructive effect on the skin and eye. Doses so low that they give rise only to normally acceptable or even desirable acute effects can, if repeated, induce changes resulting in late effects such as elastosis of the skin, keratosis and skin cancers. These effects will be of greater significance in people with lightly pigmented skin. 130 refs, 13 figs, 2 tabs

  7. MODELING ATMOSPHERIC EMISSION FOR CMB GROUND-BASED OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Errard, J.; Borrill, J. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Ade, P. A. R. [School of Physics and Astronomy, Cardiff University, Cardiff CF10 3XQ (United Kingdom); Akiba, Y.; Chinone, Y. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Arnold, K.; Atlas, M.; Barron, D.; Elleflot, T. [Department of Physics, University of California, San Diego, CA 92093-0424 (United States); Baccigalupi, C.; Fabbian, G. [International School for Advanced Studies (SISSA), Trieste I-34014 (Italy); Boettger, D. [Department of Astronomy, Pontifica Universidad Catolica de Chile (Chile); Chapman, S. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); Cukierman, A. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Delabrouille, J. [AstroParticule et Cosmologie, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cité (France); Dobbs, M.; Gilbert, A. [Physics Department, McGill University, Montreal, QC H3A 0G4 (Canada); Ducout, A.; Feeney, S. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Feng, C. [Department of Physics and Astronomy, University of California, Irvine (United States); and others

    2015-08-10

    Atmosphere is one of the most important noise sources for ground-based cosmic microwave background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3D-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive a new analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using an original numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the polarbear-i project first season data set. We derive a new 1.0% upper limit on the linear polarization fraction of atmospheric emission. We also compare our results to previous studies and weather station measurements. The proposed model can be used for realistic simulations of future ground-based CMB observations.

  8. Strong Sporadic E Occurrence Detected by Ground-Based GNSS

    Science.gov (United States)

    Sun, Wenjie; Ning, Baiqi; Yue, Xinan; Li, Guozhu; Hu, Lianhuan; Chang, Shoumin; Lan, Jiaping; Zhu, Zhengping; Zhao, Biqiang; Lin, Jian

    2018-04-01

    The ionospheric sporadic E (Es) layer has significant impact on radio wave propagation. The traditional techniques employed for Es layer observation, for example, ionosondes, are not dense enough to resolve the morphology and dynamics of Es layer in spatial distribution. The ground-based Global Navigation Satellite Systems (GNSS) technique is expected to shed light on the understanding of regional strong Es occurrence, owing to the facts that the critical frequency (foEs) of strong Es structure is usually high enough to cause pulse-like disturbances in GNSS total electron content (TEC), and a large number of GNSS receivers have been deployed all over the world. Based on the Chinese ground-based GNSS networks, including the Crustal Movement Observation Network of China and the Beidou Ionospheric Observation Network, a large-scale strong Es event was observed in the middle latitude of China. The strong Es shown as a band-like structure in the southwest-northeast direction extended more than 1,000 km. By making a comparative analysis of Es occurrences identified from the simultaneous observations by ionosondes and GNSS TEC receivers over China middle latitude statistically, we found that GNSS TEC can be well employed to observe strong Es occurrence with a threshold value of foEs, 14 MHz.

  9. Coordinated Ground-Based Observations and the New Horizons Fly-by of Pluto

    Science.gov (United States)

    Young, Eliot; Young, Leslie; Parker, Joel; Binzel, Richard

    2015-04-01

    The New Horizons (NH) spacecraft is scheduled to make its closest approach to Pluto on July 14, 2015. NH carries seven scientific instruments, including separate UV and Visible-IR spectrographs, a long-focal-length imager, two plasma-sensing instruments and a dust counter. There are three arenas in particular in which ground-based observations should augment the NH instrument suite in synergistic ways: IR spectra at wavelengths longer than 2.5 µm (i.e., longer than the NH Ralph spectrograph), stellar occultation observations near the time of the fly-by, and thermal surface maps and atmospheric CO abundances based on ALMA observations - we discuss the first two of these. IR spectra in the 3 - 5 µm range cover the CH4 absorption band near 3.3 µm. This band can be an important constraint on the state and areal extent of nitrogen frost on Pluto's surface. If this band depth is close to zero (as was observed by Olkin et al. 2007), it limits the area of nitrogen frost, which is bright at that wavelength. Combined with the NH observations of nitrogen frost at 2.15 µm, the ground-based spectra will determine how much nitrogen frost is diluted with methane, which is a basic constraint on the seasonal cycle of sublimation and condensation that takes place on Pluto (and similar objects like Triton and Eris). There is a fortuitous stellar occultation by Pluto on 29-JUN-2015, only two weeks before the NH closest approach. The occulted star will be the brightest ever observed in a Pluto event, about 2 magnitudes brighter than Pluto itself. The track of the event is predicted to cover parts of Australia and New Zealand. Thanks to HST and ground based campaigns to find a TNO target reachable by NH, the position of the shadow path will be known at the +/-100 km level, allowing SOFIA and mobile ground-based observers to reliably cover the central flash region. Ground-based & SOFIA observations in visible and IR wavelengths will characterize the haze opacity and vertical

  10. Ground-based remote sensing observation of the complex behaviour of the Marseille boundary layer during ESCOMPTE

    Science.gov (United States)

    Delbarre, H.; Augustin, P.; Saïd, F.; Campistron, B.; Bénech, B.; Lohou, F.; Puygrenier, V.; Moppert, C.; Cousin, F.; Fréville, P.; Fréjafon, E.

    2005-03-01

    Ground-based remote sensing systems have been used during the ESCOMPTE campaign, to continuously characterize the boundary-layer behaviour through many atmospheric parameters (wind, extinction and ozone concentration distribution, reflectivity, turbulence). This analysis is focused on the comparison of the atmospheric stratification retrieved from a UV angular ozone lidar, an Ultra High Frequency wind profiler and a sodar, above the area of Marseille, on June 26th 2001 (Intensive Observation Period 2b). The atmospheric stratification is shown to be very complex including two superimposed sea breezes, with an important contribution of advection. The temporal and spatial evolution of the stratification observed by the UV lidar and by the UHF radar are in good agreement although the origin of the echoes of these systems is quite different. The complexity of the dynamic situation has only partially been retrieved by a non-hydrostatic mesoscale model used with a 3 km resolution.

  11. Ultraviolet continuum variability and visual flickering in the peculiar object MWC 560

    Science.gov (United States)

    Michalitsianos, A. G.; Perez, M.; Shore, S. N.; Maran, S. P.; Karovska, M.; Sonneborn, G.; Webb, J. R.; Barnes, Thomas G., III; Frueh, Marian L.; Oliversen, R. J.

    1993-01-01

    High-speed U-band photometry of the peculiar emission object MWC 560 obtained with the ground-based instrumentation, and V-band photometry obtained with the International Ultraviolet Explorer-Fine Error Sensor indicates irregular brightness variations are quasi-periodic. Multiple peaks of relative brightness power indicate statistically significant quasi periods existing in a range of 3-35 minutes, that are superposed on slower hourly varying components. We present a preliminary model that explains the minute and hourly time-scale variations in MWC 560 in terms of a velocity-shear instability that arises because a white dwarf magnetosphere impinges on an accretion disk. We also find evidence for Fe II multiplet pseudocontinuum absorption opacity in far-UV spectra of CH Cygni which is also present in MWC 560. Both CH Cyg and MWC 560 may be in an evolutionary stage that is characterized by strong UV continuum opacity which changes significantly during outburst, occurring before they permanently enter the symbiotic nebular emission phase.

  12. SimUVEx v2 : a numeric tool to predict anatomical solar ultraviolet exposure

    OpenAIRE

    Religi, Arianna; Moccozet, Laurent; Farahmand, Meghdad; Vuilleumier, L.aurent; Vernez, David; Milon, Antoine; Backes, Claudine; Bulliard, Jean-Luc

    2016-01-01

    Solar ultraviolet (UV) radiation has a dual effect on human health: low UV doses promote the photosynthesis of vitamin D and regulate calcium and phosphorus metabolism, while an excessive UV exposure is the main cause of skin cancer, along with eye diseases and premature skin ageing. The link between UV radiation levels and UV exposure is not fully understood since exposure data are limited and individual anatomical variations in UV doses are significant. SimUVEx is a numeric simulation tool ...

  13. Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based...

  14. Phototherapy cabinet for ultraviolet radiation therapy

    International Nuclear Information System (INIS)

    Horwitz, S.N.; Frost, P.

    1981-01-01

    A newly designed cabinet can be used for the treatment of psoriasis with fluorescent ultraviolet (UV) lamps. the new design provides more uniform distribution of UV radiation in both the horizontal and vertical axes, and several safety features have been added. The distribution and uniformity of UV output in this and in a previously described cabinet are compared. The UV output at the vertical center of the older UV light cabinet was six times greater than that at either the top or bottom, while the design of the present cabinet provides uniform UV radiation except for a slight increase at head height and at the level of the lower legs compared with the middle third of the cabinet. The variation in output of the older cabinet may, in part, explain the commonly encountered difficulty in the phototherapy of psoriasis of the scalp and lower extremities

  15. Human exposure to ultraviolet radiation

    International Nuclear Information System (INIS)

    Bernhardt, J.H.; Matthes, R.

    1987-01-01

    Ultraviolet radiation is that part of the electromagnetic spectrum located between the softest ionizing radiation and visible radiation. The lower limit of 100 nm is equivalent to photon energies of 12.4 eV, which corresponds approximately to the limit for the production of ionization in biologically important materials. A historical subdividing of the UV-region takes some of the biological effects into account. In this arrangement the range 400-315 nm, the so-called black light region, is called UV-A. In this wavelength region, fluorescence can be induced in many substances. UV-B covers the range 315-280 nm (the skin erythemal region). Most of the biologically active and potentially harmful UV from the sun reaching the surface of the earth is part of this spectral region. UV-C includes the radiation of wavelengths less than 280 nm (the germicidal region). It should be noted that this classification is somewhat arbitrary, and today it is more usual to evaluate the biological effectiveness of the whole UV-range from 200 to 400 nm

  16. Pollen and spores as biological recorders of past ultraviolet irradiance

    NARCIS (Netherlands)

    Jardine, P.E.; Fraser, W.T.; Lomax, B.H.; Sephton, M.A.; Shanahan, T.M.; Miller, C.S.; Gosling, W.D.

    2016-01-01

    Solar ultraviolet (UV) irradiance is a key driver of climatic and biotic change. Ultraviolet irradiance modulates stratospheric warming and ozone production, and influences the biosphere from ecosystem-level processes through to the largest scale patterns of diversification and extinction. Yet our

  17. Ultraviolet and Infrared Correlation Studies in Orion

    Directory of Open Access Journals (Sweden)

    Bose Lakshmi S.

    2015-09-01

    Full Text Available We have studied the variation of diffuse ultraviolet (UV radiation in the northern part of the Orion constellation using a set of eight areas of the GALEX All-Sky Imaging Survey in the far and near UV. Different components of diffuse UV radiation, like dust scattered emission and H2 fluorescence, were quantified and separated after removing the point sources and the foreground emission in each of the fields. Then the dependence of the individual UV components on the infrared 100 μm dust emission was studied. We did not find any positive correlation between the diffuse-UV and IR-100 micron intensities, probably due to the high optical depth of the region or the entire dust column not contributing to the diffuse UV radiation. However, in the far UV we noticed the presence of an excess emission in addition to the dust scattered radiation, which is clearly absent in the near UV. This excess emission, identified as the H2 fluorescence, is produced by the Trapezium stars in the surrounding molecular clouds. We also compare our results with those of previous studies in the region, based on Far Ultraviolet Spectroscopic Explorer (FUSE observations.

  18. Influence of uvA on the erythematogenic and therapeutic effects of uvB irradiation in psoriasis; photoaugmentation effects

    International Nuclear Information System (INIS)

    Boer, J.; Schothorst, A.A.; Suurmond, D.

    1981-01-01

    The effect of repeated exposure to an additive dose of long ultraviolet (uvA) radiation on the erythemogenic and therapeutic effects of middle ultraviolet (uvB) irradiation was investigated in 8 patients with psoriasis. The surface of the backs of these patients was divided into 2 parts, 1 of which received only uvB irradiation 4 times a week and the other uvA + uvB. uvB was provided by Philips TL-12 lamps and uvA by glass-filtered Philips TL-09 lamps. uvA was held constantly at 10 J/cm2, whereas uvB alone were evaluated by 4 tests during the treatment to determine the minimal erythema dose (MED). Test I (at the start of the therapy) showed a photoaugmentative effect which was no longer apparent in Test III (third week). Test III showed a reversal of the ratios of the MEDs of the sites irradiated with the uvA + uvB and uvB (MED A + B/MED B). This is ascribed to the marked pigmentation which appeared after repeated irradiation with the uvA + uvB combination. Comparison showed for the improvement of the psoriasis no distinct differences between uvA + uvB irradiation and uvB alone, but the former had the cosmetic advantage of giving pleasing tan

  19. Ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    UVR can be classified into UV-A, UV-B, and UV-C regions. A long period of UVR deficiency may have a harmful effect on the human body. The best known manifestation of UVR deficiency is the development of vitamin D deficiency and rickets in children because of a disturbance in the phosphorus and calcium metabolism. The acute effects of UVR on the eyes consist of the development of photokeratitis and photoconjunctivitis. Acute effects on the skin consist of solar erythema sunburn. Chronic effects on the eye consist of the development of pterygium and squamous cell cancer of the conjunctiva and perhaps cataracts. Chronic skin changes due to UVR consist of aging and the induction of premalignant changes and malignant skin tumours. Criteria for occupational exposure levels in work places have been proposed. It must be recognized that significant nonoccupational exposure to UVR occurs from exposure to sunlight. Thus, exposure limits for the general population are difficult to recommend. Finally, the document describes existing protection and control measures such as the containment of UVR sources, and methods for personal protection including the use of sunscreen preparations, clothing, transparent material for eye and skin protection, and behavioural modifications.

  20. Reconstruction of Sky Illumination Domes from Ground-Based Panoramas

    Science.gov (United States)

    Coubard, F.; Lelégard, L.; Brédif, M.; Paparoditis, N.; Briottet, X.

    2012-07-01

    The knowledge of the sky illumination is important for radiometric corrections and for computer graphics applications such as relighting or augmented reality. We propose an approach to compute environment maps, representing the sky radiance, from a set of ground-based images acquired by a panoramic acquisition system, for instance a mobile-mapping system. These images can be affected by important radiometric artifacts, such as bloom or overexposure. A Perez radiance model is estimated with the blue sky pixels of the images, and used to compute additive corrections in order to reduce these radiometric artifacts. The sky pixels are then aggregated in an environment map, which still suffers from discontinuities on stitching edges. The influence of the quality of estimated sky radiance on the simulated light signal is measured quantitatively on a simple synthetic urban scene; in our case, the maximal error for the total sensor radiance is about 10%.

  1. Ground-based transmission line conductor motion sensor

    International Nuclear Information System (INIS)

    Jacobs, M.L.; Milano, U.

    1988-01-01

    A ground-based-conductor motion-sensing apparatus is provided for remotely sensing movement of electric-power transmission lines, particularly as would occur during the wind-induced condition known as galloping. The apparatus is comprised of a motion sensor and signal-generating means which are placed underneath a transmission line and will sense changes in the electric field around the line due to excessive line motion. The detector then signals a remote station when a conditioning of galloping is sensed. The apparatus of the present invention is advantageous over the line-mounted sensors of the prior art in that it is easier and less hazardous to install. The system can also be modified so that a signal will only be given when particular conditions, such as specific temperature range, large-amplitude line motion, or excessive duration of the line motion, are occurring

  2. RECONSTRUCTION OF SKY ILLUMINATION DOMES FROM GROUND-BASED PANORAMAS

    Directory of Open Access Journals (Sweden)

    F. Coubard

    2012-07-01

    Full Text Available The knowledge of the sky illumination is important for radiometric corrections and for computer graphics applications such as relighting or augmented reality. We propose an approach to compute environment maps, representing the sky radiance, from a set of ground-based images acquired by a panoramic acquisition system, for instance a mobile-mapping system. These images can be affected by important radiometric artifacts, such as bloom or overexposure. A Perez radiance model is estimated with the blue sky pixels of the images, and used to compute additive corrections in order to reduce these radiometric artifacts. The sky pixels are then aggregated in an environment map, which still suffers from discontinuities on stitching edges. The influence of the quality of estimated sky radiance on the simulated light signal is measured quantitatively on a simple synthetic urban scene; in our case, the maximal error for the total sensor radiance is about 10%.

  3. Satellite and Ground Based Monitoring of Aerosol Plumes

    International Nuclear Information System (INIS)

    Doyle, Martin; Dorling, Stephen

    2002-01-01

    Plumes of atmospheric aerosol have been studied using a range of satellite and ground-based techniques. The Sea-viewing WideField-of-view Sensor (SeaWiFS) has been used to observe plumes of sulphate aerosol and Saharan dust around the coast of the United Kingdom. Aerosol Optical Thickness (AOT) was retrieved from SeaWiFS for two events; a plume of Saharan dust transported over the United Kingdom from Western Africa and a period of elevated sulphate experienced over the Easternregion of the UK. Patterns of AOT are discussed and related to the synoptic and mesoscale weather conditions. Further observation of the sulphate aerosol event was undertaken using the Advanced Very High Resolution Radiometer instrument(AVHRR). Atmospheric back trajectories and weather conditions were studied in order to identify the meteorological conditions which led to this event. Co-located ground-based measurements of PM 10 and PM 2.5 were obtained for 4sites within the UK and PM 2.5/10 ratios were calculated in order to identify any unusually high or low ratios(indicating the dominant size fraction within the plume)during either of these events. Calculated percentiles ofPM 2.5/10 ratios during the 2 events examined show that these events were notable within the record, but were in noway unique or unusual in the context of a 3 yr monitoring record. Visibility measurements for both episodes have been examined and show that visibility degradation occurred during both the sulphate aerosol and Saharan dust episodes

  4. Solar ultraviolet hazards

    International Nuclear Information System (INIS)

    Azmah Ali

    1995-01-01

    The paper discussed the following subjects: the sources of ultraviolet radiation, solar ultraviolet radiation definition, effects of over exposure to solar ultraviolet radiation, exposure limits and radiation protection of this radiation

  5. Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs - abstract

    Science.gov (United States)

    Background: Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment appli...

  6. Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs

    Science.gov (United States)

    Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, suc...

  7. Solar ultraviolet radiation cataract.

    Science.gov (United States)

    Löfgren, Stefan

    2017-03-01

    Despite being a treatable disease, cataract is still the leading cause for blindness in the world. Solar ultraviolet radiation is epidemiologically linked to cataract development, while animal and in vitro studies prove a causal relationship. However, the pathogenetic pathways for the disease are not fully understood and there is still no perfect model for human age related cataract. This non-comprehensive overview focus on recent developments regarding effects of solar UV radiation wavebands on the lens. A smaller number of fundamental papers are also included to provide a backdrop for the overview. Future studies are expected to further clarify the cellular and subcellular mechanisms for UV radiation-induced cataract and especially the isolated or combined temporal and spatial effects of UVA and UVB in the pathogenesis of human cataract. Regardless of the cause for cataract, there is a need for advances in pharmaceutical or other treatment modalities that do not require surgical replacement of the lens. Copyright © 2016. Published by Elsevier Ltd.

  8. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1996-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  9. Ultraviolet radiation: the eye

    International Nuclear Information System (INIS)

    Cesarini, J.P.; Sliney, D.H.

    1996-01-01

    Under most conditions, the eye is well adapted to protect itself against ultraviolet radiation encountered in the outdoor environment as a result of the exposure geometry of the sun. Only when snow is on the ground does one experience acute effects of UV sunlight exposure (i.e. snow blindness, or photokeratitis). With regard to artificial sources, there are many occasions where one views bright light sources such as tungsten-halogen lamps, arc lamps and welding arcs. Such viewing is normally only momentary because of the aversion response to bright light and due to discomfort glare. However, such an aversion does not take place for germicidal lamps and other UV lamps which do not contain a strong visible component in their spectrum. The adverse effects from viewing such sources has been studied for decades and during the last two decades guidelines for limiting exposure to protect the eye have been developed. The guidelines were fostered to a large extent by the growing use of lasers and the quickly recognized hazard posed by viewing laser sources. (author)

  10. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P; Koskela, T; Damski, J; Supperi, A [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1997-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  11. Ultraviolet air disinfection for protection against influenza

    International Nuclear Information System (INIS)

    Riley, R.L.

    1977-01-01

    Three converging lines of evidence support the belief that it may be possible, under appropriate circumstances, to interrupt the airborne transmission of influenza by ultraviolet (UV) air disinfection. These lines of evidence are: (a) that influenza is airborne; (b) that UV irradiation of the upper air of a room can provide safe and effective disinfection of air in the lower part of the room; and (c) that epidemic spread of airborne viral infections in humans can be prevented if the population under consideration remains in the UV-protected environment

  12. THE DETECTION RATE OF EARLY UV EMISSION FROM SUPERNOVAE: A DEDICATED GALEX/PTF SURVEY AND CALIBRATED THEORETICAL ESTIMATES

    Energy Technology Data Exchange (ETDEWEB)

    Ganot, Noam; Gal-Yam, Avishay; Ofek, Eran O.; Sagiv, Ilan; Waxman, Eli; Lapid, Ofer [Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Kulkarni, Shrinivas R.; Kasliwal, Mansi M. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Ben-Ami, Sagi [Smithsonian Astrophysical Observatory, Harvard-Smithsonian Ctr. for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chelouche, Doron; Rafter, Stephen [Physics Department, Faculty of Natural Sciences, University of Haifa, 31905 Haifa (Israel); Behar, Ehud; Laor, Ari [Physics Department, Technion Israel Institute of Technology, 32000 Haifa (Israel); Poznanski, Dovi; Nakar, Ehud; Maoz, Dan [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Trakhtenbrot, Benny [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27 Zurich 8093 (Switzerland); Neill, James D.; Barlow, Thomas A.; Martin, Christofer D., E-mail: noam.ganot@gmail.com [California Institute of Technology, 1200 East California Boulevard, MC 278-17, Pasadena, CA 91125 (United States); Collaboration: ULTRASAT Science Team; WTTH consortium; GALEX Science Team; Palomar Transient Factory; and others

    2016-03-20

    The radius and surface composition of an exploding massive star, as well as the explosion energy per unit mass, can be measured using early UV observations of core-collapse supernovae (SNe). We present the first results from a simultaneous GALEX/PTF search for early ultraviolet (UV) emission from SNe. Six SNe II and one Type II superluminous SN (SLSN-II) are clearly detected in the GALEX near-UV (NUV) data. We compare our detection rate with theoretical estimates based on early, shock-cooling UV light curves calculated from models that fit existing Swift and GALEX observations well, combined with volumetric SN rates. We find that our observations are in good agreement with calculated rates assuming that red supergiants (RSGs) explode with fiducial radii of 500 R{sub ⊙}, explosion energies of 10{sup 51} erg, and ejecta masses of 10 M{sub ⊙}. Exploding blue supergiants and Wolf–Rayet stars are poorly constrained. We describe how such observations can be used to derive the progenitor radius, surface composition, and explosion energy per unit mass of such SN events, and we demonstrate why UV observations are critical for such measurements. We use the fiducial RSG parameters to estimate the detection rate of SNe during the shock-cooling phase (<1 day after explosion) for several ground-based surveys (PTF, ZTF, and LSST). We show that the proposed wide-field UV explorer ULTRASAT mission is expected to find >85 SNe per year (∼0.5 SN per deg{sup 2}), independent of host galaxy extinction, down to an NUV detection limit of 21.5 mag AB. Our pilot GALEX/PTF project thus convincingly demonstrates that a dedicated, systematic SN survey at the NUV band is a compelling method to study how massive stars end their life.

  13. Ultraviolet spectrophotometry of three LINERs

    Science.gov (United States)

    Goodrich, R. W.; Keel, W. C.

    1986-01-01

    Three galaxies known to be LINERs were observed spectroscopically in the ultraviolet in an attempt to detect the presumed nonthermal continuum source thought to be the source of photoionization in the nuclei. NGC 4501 was found to be too faint for study with the IUE spectrographs, while NGC 5005 had an extended ultraviolet light profile. Comparison with the optical light profile of NGC 5005 indicates that the ultraviolet source is distributed spatially in the same manner as the optical starlight, probably indicating that the ultraviolet excess is due to a component of hot stars in the nucleus. These stars contribute detectable absorption features longward of 2500 A; together with optical data, the IUE spectra suggest a burst of star formation about 1 billion yr ago, with a lower rate continuing to produce a few OB stars. In NGC 4579, a point source contributing most of the ultraviolet excess is found that is much different than the optical light distribution. Furthermore, the ultraviolet to X-ray spectral index in NGC 4579 is 1.4, compatible with the UV to X-ray indices found for samples of Seyfert galaxies. This provides compelling evidence for the detection of the photoionizing continuum in NGC 4579 and draws the research fields of normal galaxies and active galactic nuclei closer together. The emission-line spectrum of NGC 4579 is compared with calculations from a photoionization code, CLOUDY, and several shock models. The photoionization code is found to give superior results, adding to the increasing weight of evidence that the LINER phenomenon is essentially a scaled-down version of the Seyfert phenomenon.

  14. The MUSCLES Treasury Survey. IV. Scaling Relations for Ultraviolet, Ca II K, and Energetic Particle Fluxes from M Dwarfs

    Science.gov (United States)

    Youngblood, Allison; France, Kevin; Loyd, R. O. Parke; Brown, Alexander; Mason, James P.; Schneider, P. Christian; Tilley, Matt A.; Berta-Thompson, Zachory K.; Buccino, Andrea; Froning, Cynthia S.; Hawley, Suzanne L.; Linsky, Jeffrey; Mauas, Pablo J. D.; Redfield, Seth; Kowalski, Adam; Miguel, Yamila; Newton, Elisabeth R.; Rugheimer, Sarah; Segura, Antígona; Roberge, Aki; Vieytes, Mariela

    2017-07-01

    Characterizing the UV spectral energy distribution (SED) of an exoplanet host star is critically important for assessing its planet’s potential habitability, particularly for M dwarfs, as they are prime targets for current and near-term exoplanet characterization efforts and atmospheric models predict that their UV radiation can produce photochemistry on habitable zone planets different from that on Earth. To derive ground-based proxies for UV emission for use when Hubble Space Telescope (HST) observations are unavailable, we have assembled a sample of 15 early to mid-M dwarfs observed by HST and compared their nonsimultaneous UV and optical spectra. We find that the equivalent width of the chromospheric Ca II K line at 3933 Å, when corrected for spectral type, can be used to estimate the stellar surface flux in ultraviolet emission lines, including H I Lyα. In addition, we address another potential driver of habitability: energetic particle fluxes associated with flares. We present a new technique for estimating soft X-ray and >10 MeV proton flux during far-UV emission line flares (Si IV and He II) by assuming solar-like energy partitions. We analyze several flares from the M4 dwarf GJ 876 observed with HST and Chandra as part of the MUSCLES Treasury Survey and find that habitable zone planets orbiting GJ 876 are impacted by large Carrington-like flares with peak soft X-ray fluxes ≥10-3 W m-2 and possible proton fluxes ˜102-103 pfu, approximately four orders of magnitude more frequently than modern-day Earth.

  15. The MUSCLES Treasury Survey. IV. Scaling Relations for Ultraviolet, Ca ii K, and Energetic Particle Fluxes from M Dwarfs

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, Allison; France, Kevin; Loyd, R. O. Parke; Mason, James P. [Laboratory for Atmospheric and Space Physics, University of Colorado, 600 UCB, Boulder, CO 80309 (United States); Brown, Alexander [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Schneider, P. Christian [European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Tilley, Matt A. [Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195 (United States); Berta-Thompson, Zachory K.; Kowalski, Adam [Department of Astrophysical and Planetary Sciences, University of Colorado, 2000 Colorado Ave., Boulder, CO 80305 (United States); Buccino, Andrea; Mauas, Pablo J. D. [Dpto. de Física, Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires (Argentina); Froning, Cynthia S. [Department of Astronomy/McDonald Observatory, C1400, University of Texas at Austin, Austin, TX 78712 (United States); Hawley, Suzanne L. [Astronomy Department, Box 351580, University of Washington, Seattle, WA 98195 (United States); Linsky, Jeffrey [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Redfield, Seth [Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459 (United States); Miguel, Yamila [Observatoire de la Cote d’Azur, Boulevard de l’Observatoire, CS 34229 F-06304 NICE Cedex 4 (France); Newton, Elisabeth R. [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02138 (United States); Rugheimer, Sarah, E-mail: allison.youngblood@colorado.edu [School of Earth and Environmental Sciences, University of St. Andrews, Irvine Building, North Street, St. Andrews, KY16 9AL (United Kingdom); and others

    2017-07-01

    Characterizing the UV spectral energy distribution (SED) of an exoplanet host star is critically important for assessing its planet’s potential habitability, particularly for M dwarfs, as they are prime targets for current and near-term exoplanet characterization efforts and atmospheric models predict that their UV radiation can produce photochemistry on habitable zone planets different from that on Earth. To derive ground-based proxies for UV emission for use when Hubble Space Telescope ( HST ) observations are unavailable, we have assembled a sample of 15 early to mid-M dwarfs observed by HST and compared their nonsimultaneous UV and optical spectra. We find that the equivalent width of the chromospheric Ca ii K line at 3933 Å, when corrected for spectral type, can be used to estimate the stellar surface flux in ultraviolet emission lines, including H i Ly α . In addition, we address another potential driver of habitability: energetic particle fluxes associated with flares. We present a new technique for estimating soft X-ray and >10 MeV proton flux during far-UV emission line flares (Si iv and He ii) by assuming solar-like energy partitions. We analyze several flares from the M4 dwarf GJ 876 observed with HST and Chandra as part of the MUSCLES Treasury Survey and find that habitable zone planets orbiting GJ 876 are impacted by large Carrington-like flares with peak soft X-ray fluxes ≥10{sup −3} W m{sup −2} and possible proton fluxes ∼10{sup 2}–10{sup 3} pfu, approximately four orders of magnitude more frequently than modern-day Earth.

  16. The MUSCLES Treasury Survey. IV. Scaling Relations for Ultraviolet, Ca ii K, and Energetic Particle Fluxes from M Dwarfs

    International Nuclear Information System (INIS)

    Youngblood, Allison; France, Kevin; Loyd, R. O. Parke; Mason, James P.; Brown, Alexander; Schneider, P. Christian; Tilley, Matt A.; Berta-Thompson, Zachory K.; Kowalski, Adam; Buccino, Andrea; Mauas, Pablo J. D.; Froning, Cynthia S.; Hawley, Suzanne L.; Linsky, Jeffrey; Redfield, Seth; Miguel, Yamila; Newton, Elisabeth R.; Rugheimer, Sarah

    2017-01-01

    Characterizing the UV spectral energy distribution (SED) of an exoplanet host star is critically important for assessing its planet’s potential habitability, particularly for M dwarfs, as they are prime targets for current and near-term exoplanet characterization efforts and atmospheric models predict that their UV radiation can produce photochemistry on habitable zone planets different from that on Earth. To derive ground-based proxies for UV emission for use when Hubble Space Telescope ( HST ) observations are unavailable, we have assembled a sample of 15 early to mid-M dwarfs observed by HST and compared their nonsimultaneous UV and optical spectra. We find that the equivalent width of the chromospheric Ca ii K line at 3933 Å, when corrected for spectral type, can be used to estimate the stellar surface flux in ultraviolet emission lines, including H i Ly α . In addition, we address another potential driver of habitability: energetic particle fluxes associated with flares. We present a new technique for estimating soft X-ray and >10 MeV proton flux during far-UV emission line flares (Si iv and He ii) by assuming solar-like energy partitions. We analyze several flares from the M4 dwarf GJ 876 observed with HST and Chandra as part of the MUSCLES Treasury Survey and find that habitable zone planets orbiting GJ 876 are impacted by large Carrington-like flares with peak soft X-ray fluxes ≥10 −3 W m −2 and possible proton fluxes ∼10 2 –10 3 pfu, approximately four orders of magnitude more frequently than modern-day Earth.

  17. Ultraviolet and environmental stresses involved in the induction and ...

    African Journals Online (AJOL)

    Light is one of the most important environmental factors regulating plant development and genes expression. Ultraviolet takes up 7% of sunlight and it stimulates distinct responses in plant. Both UV-A and low influence of UV-B can induce the accumulation of anthocyanin via induction of the expression of anthocyanin ...

  18. LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVIATION OF GIARDIA MURIS CYSTS

    Science.gov (United States)

    This research was initiated to confirm and expand the current database for the inactiviation of Giardia spp. using ultraviolet (UV) radiation. The path taken was to confirm earlier UV research that used excystation as the indication of viability. In this study, an in vitro excyst...

  19. LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS

    Science.gov (United States)

    This research was initiated to confirm and expand the current database for the inactivation of Giardia spp. using ultraviolet (UV) radiation. Initially, previous research that used in vitro excystation as the indicator for UV effectiveness was confirmed. Later, the in vitro excys...

  20. Adverse effects of ultraviolet irradiation in atopic dermatitis.

    NARCIS (Netherlands)

    ten Berge, O.

    2010-01-01

    The overall aim of this thesis was to evaluate adverse effects of ultraviolet irradiation (UV) in atopic dermatitis (AD). We focused on the two important adverse effects of UV: photosensitivity and skin cancer risk associated with calcineurin inhibitor treatment. In chapter 2 and 3 we found that

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  2. 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.

  3. Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

    Science.gov (United States)

    Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

    2011-02-01

    A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Recovery of phage lambda from ultraviolet damage

    International Nuclear Information System (INIS)

    Devoret, R.; Blanco, M.; George, J.; Radman, M.

    1975-01-01

    Recovery of phage lambda from ultraviolet damage can occur, in the dark, through three types of repair processes as defined by microbiological tests: host-cell reactivation, prophage reactivation, and uv reactivation. This paper reviews the properties of the three repair processes, analyzes their dependence on the functioning of bacterial and phage genes, and discusses their relationship. Progress in the understanding of the molecular mechanisms underlying the three repair processes has been relatively slow, particularly for uv reactivation. It has been shown that host-cell reactivation is due to pyrimidine dimer excision and that prophage reactivation is due to genetic recombination (prereplicative). We provide evidence showing that neither of these mechanisms accounts for uv reactivation of phage lambda. Furthermore, uv reactivation differs from the other repair processes in that it is inducible and error-prone. Whether uv-damaged bacterial DNA is subject to a similar repair process is still an open question

  5. Some resistance mechanisms to ultraviolet radiation

    International Nuclear Information System (INIS)

    Alcantara D, D.

    2002-12-01

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

  6. Free-electron lasers in ultraviolet photobiology

    International Nuclear Information System (INIS)

    Coohill, T.P.; Sutherland, J.C.

    1989-01-01

    The potential uses for a free-electron laser (FEL), tunable in wavelength from 10 to 400 nm, for photobiological experiments is discussed. Inherent problems of cell and molecular absorption, especially in certain regions of the ultraviolet (UV), are addressed. Absorption values for living cells and viruses at selected wavelengths in the UV are tabulated, and a calculation of the flux needed to inactivate mammalian cells is included. A comparison is made of the UV output of a proposed rf-linac FEL with those of a monochromator, a tunable dye laser, and a synchrotron. The advantages of a UV FEL are apparent, especially in the wavelength regions where the cross section for absorption by biological molecules is low, i.e., 300 to 400 nm and 10 to 200 nm. It is apparent that a UV FEL would be an ideal source for a variety of biological studies that use both intact organisms and isolated cells and viruses

  7. Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

    International Nuclear Information System (INIS)

    Chiara, P.; Morelli, A.

    2010-01-01

    The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements.Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken.This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

  8. Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

    Science.gov (United States)

    Chiara, P.; Morelli, A.

    2010-05-01

    The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements. Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken. This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

  9. Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements

    Science.gov (United States)

    Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.

    2011-01-01

    Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background TEC value. Observations near the epicenter are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.

  10. A design for a ground-based data management system

    Science.gov (United States)

    Lambird, Barbara A.; Lavine, David

    1988-01-01

    An initial design for a ground-based data management system which includes intelligent data abstraction and cataloging is described. The large quantity of data on some current and future NASA missions leads to significant problems in providing scientists with quick access to relevant data. Human screening of data for potential relevance to a particular study is time-consuming and costly. Intelligent databases can provide automatic screening when given relevent scientific parameters and constraints. The data management system would provide, at a minimum, information of availability of the range of data, the type available, specific time periods covered together with data quality information, and related sources of data. The system would inform the user about the primary types of screening, analysis, and methods of presentation available to the user. The system would then aid the user with performing the desired tasks, in such a way that the user need only specify the scientific parameters and objectives, and not worry about specific details for running a particular program. The design contains modules for data abstraction, catalog plan abstraction, a user-friendly interface, and expert systems for data handling, data evaluation, and application analysis. The emphasis is on developing general facilities for data representation, description, analysis, and presentation that will be easily used by scientists directly, thus bypassing the knowledge acquisition bottleneck. Expert system technology is used for many different aspects of the data management system, including the direct user interface, the interface to the data analysis routines, and the analysis of instrument status.

  11. Use of ground-based wind profiles in mesoscale forecasting

    Science.gov (United States)

    Schlatter, Thomas W.

    1985-01-01

    A brief review is presented of recent uses of ground-based wind profile data in mesoscale forecasting. Some of the applications are in real time, and some are after the fact. Not all of the work mentioned here has been published yet, but references are given wherever possible. As Gage and Balsley (1978) point out, sensitive Doppler radars have been used to examine tropospheric wind profiles since the 1970's. It was not until the early 1980's, however, that the potential contribution of these instruments to operational forecasting and numerical weather prediction became apparent. Profiler winds and radiosonde winds compare favorably, usually within a few m/s in speed and 10 degrees in direction (see Hogg et al., 1983), but the obvious advantage of the profiler is its frequent (hourly or more often) sampling of the same volume. The rawinsonde balloon is launched only twice a day and drifts with the wind. In this paper, I will: (1) mention two operational uses of data from a wind profiling system developed jointly by the Wave Propagation and Aeronomy Laboratories of NOAA; (2) describe a number of displays of these same data on a workstation for mesoscale forecasting developed by the Program for Regional Observing and Forecasting Services (PROFS); and (3) explain some interesting diagnostic calculations performed by meteorologists of the Wave Propagation Laboratory.

  12. Ground-based observations coordinated with Viking satellite measurements

    International Nuclear Information System (INIS)

    Opgenoorth, H.J.; Kirkwood, S.

    1989-01-01

    The instrumentation and the orbit of the Viking satellite made this first Swedish satellite mission ideally suited for coordinated observations with the dense network of ground-based stations in northern Scandinavia. Several arrays of complementing instruments such as magnetometers, all-sky cameras, riometers and doppler radars monitored on a routine basis the ionosphere under the magnetospheric region passed by Viking. For a large number of orbits the Viking passages close to Scandinavia were covered by the operation of specially designed programmes at the European incoherent-scatter facility (EISCAT). First results of coordinated observations on the ground and aboard Viking have shed new light on the most spectacular feature of substorm expansion, the westward-travelling surge. The end of a substorm and the associated decay of a westward-travelling surge have been analysed. EISCAT measurements of high spatial and temporal resolution indicate that the conductivities and electric fields associated with westward-travelling surges are not represented correctly by the existing models. (author)

  13. Tissue Engineering of Cartilage on Ground-Based Facilities

    Science.gov (United States)

    Aleshcheva, Ganna; Bauer, Johann; Hemmersbach, Ruth; Egli, Marcel; Wehland, Markus; Grimm, Daniela

    2016-06-01

    Investigations under simulated microgravity offer the opportunity for a better understanding of the influence of altered gravity on cells and the scaffold-free three-dimensional (3D) tissue formation. To investigate the short-term influence, human chondrocytes were cultivated for 2 h, 4 h, 16 h, and 24 h on a 2D Fast-Rotating Clinostat (FRC) in DMEM/F-12 medium supplemented with 10 % FCS. We detected holes in the vimentin network, perinuclear accumulations of vimentin after 2 h, and changes in the chondrocytes shape visualised by F-actin staining after 4 h of FRC-exposure. Scaffold-free cultivation of chondrocytes for 7 d on the Random Positioning Machine (RPM), the FRC and the Rotating Wall Vessel (RWV) resulted in spheroid formation, a phenomenon already known from spaceflight experiments with chondrocytes (MIR Space Station) and thyroid cancer cells (SimBox/Shenzhou-8 space mission). The experiments enabled by the ESA-CORA-GBF programme gave us an optimal opportunity to study gravity-related cellular processes, validate ground-based facilities for our chosen cell system, and prepare long-term experiments under real microgravity conditions in space

  14. Ground-based detection of G star superflares with NGTS

    Science.gov (United States)

    Jackman, James A. G.; Wheatley, Peter J.; Pugh, Chloe E.; Gänsicke, Boris T.; Gillen, Edward; Broomhall, Anne-Marie; Armstrong, David J.; Burleigh, Matthew R.; Chaushev, Alexander; Eigmüller, Philipp; Erikson, Anders; Goad, Michael R.; Grange, Andrew; Günther, Maximilian N.; Jenkins, James S.; McCormac, James; Raynard, Liam; Thompson, Andrew P. G.; Udry, Stéphane; Walker, Simon; Watson, Christopher A.; West, Richard G.

    2018-04-01

    We present high cadence detections of two superflares from a bright G8 star (V = 11.56) with the Next Generation Transit Survey (NGTS). We improve upon previous superflare detections by resolving the flare rise and peak, allowing us to fit a solar flare inspired model without the need for arbitrary break points between rise and decay. Our data also enables us to identify substructure in the flares. From changing starspot modulation in the NGTS data we detect a stellar rotation period of 59 hours, along with evidence for differential rotation. We combine this rotation period with the observed ROSAT X-ray flux to determine that the star's X-ray activity is saturated. We calculate the flare bolometric energies as 5.4^{+0.8}_{-0.7}× 10^{34}and 2.6^{+0.4}_{-0.3}× 10^{34}erg and compare our detections with G star superflares detected in the Kepler survey. We find our main flare to be one of the largest amplitude superflares detected from a bright G star. With energies more than 100 times greater than the Carrington event, our flare detections demonstrate the role that ground-based instruments such as NGTS can have in assessing the habitability of Earth-like exoplanets, particularly in the era of PLATO.

  15. Microbial raw data for UV-C LED disinfection study

    Data.gov (United States)

    U.S. Environmental Protection Agency — This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at...

  16. Sensitivity of ice-nucleating bacteria to ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Obata, Hitoshi; Tanahashi, Shinji; Kawahara, Hidehisa (Kansai Univ., Suita, Osaka (Japan). Faculty of Engineering)

    1992-01-01

    The effect of ultraviolet (UV) irradiation on the ice-nucleating activity of the ice-nucleating bacteria was examined. Bacterial suspension was irradiated with UV (254 nm, 6Wx2) for 5 min at a distance of 20 cm from UV source. Although no viable cells were detected, the ice-nucreating activity of the cells was not affected. Furthermore, after UV irradiation for 3 hr, the ice-nucleating activity of Pseudomonas fluorescens and P. syringae was only slightly decreased, although that of P. viridiflava and Erwinia herbicola was significantly lowered. We succeeded in killing the ice-nucleating bacteria, while retaining their ice-nucleating activity with UV irradiation. (author).

  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. Those Crafty Cepheids: Surprises From Ground-Based Photometry and HST-COS FUV Spectra

    Science.gov (United States)

    Engle, Scott G.; Guinan, E. F.; Neilson, H.; Wasatonic, R. P.; Harper, G.

    2013-06-01

    Several years ago the Secret Lives of Cepheids (SLiC) program was initiated to look for unexpected or exotic behaviors from Cepheids. Regular photometric monitoring of Cepheids already possessing robust historical datasets was started to better understand long-term pulsation period changes, but to look for possible amplitude changes as well. At the time, only two “unusual” Cepheids were known to have undergone amplitude changes - Polaris and V473 Lyr. To date, however, the SLiC program has found evidence for amplitude changes in seven other Cepheids, raising the possibility that a "Blazhko effect" could be at work in certain Cepheids, as exists in a subset of RR Lyr stars. As the program expanded, we found that previous International Ultraviolet Exporer (IUE) studies showed certain Cepheids to have UV emissions from warm-to-hot stellar atmospheres. On top of that, the emissions were variable and well-phased to the stellar pulsation period, indicating that the mechanism heating the Cepheid atmosphere was influenced by these pulsations, if not linked to them. With the installation of the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST), a modern, high-quality UV spectrograph was now operating that could efficiently obtain high-resolution spectra of the Cepheids. We have been fortunate to observe four Cepheids to date with COS, and the results are well beyond anything IUE had led us to expect. Here we will present the current optical and UV results of the SLiC program, the implications of the results, and the future direction and expansion of the program. We gratefully acknowledge support for this program from HST grants HST-GO-11726.01-A, HST-GO-12302.01-A and HST-GO-13019.01-A, as well as NSF/RUI grant AST-1009903.

  19. Ultraviolet radiation

    International Nuclear Information System (INIS)

    Hawk, J.

    1986-01-01

    Ultraviolet radiation (UVR) from the sun or artificial sources is reflected or transmitted at the surface of the skin, about 5% of normally incident rays being directly reflected. The transmitted fraction is scattered, photochemically absorbed or dissipated as heat within the skin, or passes from it to contribute to the variable total amount of reflected and transmitted radiation. The UVR absorbers in skin are not definitely known, but DNA is a definite target and probably lipoprotein membranes, RNA, proteins, mucopolysaccharides, elastin and collagen. Photochemical or free radical damage to absorber or nearby organelles leads to pharmacological, ultrastructural, histological and clinical changes. Most frequent DNA damage is pyrimidine dimer formation, apparently inhibiting cell function and replication. This is largely enzymatically repaired in man in the dark by excision repair, post-replication repair and possible other enzymatic mechanisms, and at least in some organisms by light-induced photoreactivation repair. UVR exposure causes well recognized acute and chronic clinical syndromes in man. These are discussed in this paper

  20. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    Aoki, Shigeji; Ito, Shoko; Watanabe, Takehiko

    1979-01-01

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

  1. Intercomparison of ground based and satellite pictures of the sun

    International Nuclear Information System (INIS)

    Chapman, R.D.; Epstein, G.L.; Hobbs, R.W.; Neupert, W.M.; Thomas, R.J.

    1975-01-01

    Using NASA facilities in space (OSO-7) and on the ground (Goddard Multi-Channel Spectrophotometer at Sacramento Peak, New Mexico) an active region has been mapped and by combining these ultraviolet, X-ray and visible data, a physical picture of this structured region has been constructed from the photosphere to the corona, corresponding to temperature regimes over the range 4500 K to 4 000 000 K. The morphology of the active region was then studied by comparing grey-shaded images in which fine details stand out more clearly than in the contour plots. One result of the study is that gross similarities persist from the low photosphere up to high in the transition region while some changes occur in the corona. (Auth.)

  2. Ground-based spectral measurements of solar radiation, (2)

    International Nuclear Information System (INIS)

    Murai, Keizo; Kobayashi, Masaharu; Goto, Ryozo; Yamauchi, Toyotaro

    1979-01-01

    A newly designed spectro-pyranometer was used for the measurement of the global (direct + diffuse) and the diffuse sky radiation reaching the ground. By the subtraction of the diffuse component from the global radiation, we got the direct radiation component which leads to the spectral distribution of the optical thickness (extinction coefficient) of the turbid atmosphere. The measurement of the diffuse sky radiation reveals the scattering effect of aerosols and that of the global radiation allows the estimation of total attenuation caused by scattering and absorption of aerosols. The effects of the aerosols are represented by the deviation of the real atmosphere measured from the Rayleigh atmosphere. By the combination of the measured values with those obtained by theoretical calculation for the model atmosphere, we estimated the amount of absorption by the aerosols. Very strong absorption in the ultraviolet region was recognized. (author)

  3. Failure of supplementary ultraviolet radiation to enhance flower color under greenhouse conditions

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R. M. [University of Vermont, Burlington, VT (United States)

    1990-03-15

    In order to determine whether the concentration of floral petal anthocyanin pigments could be increased, ultraviolet radiations in the UV-A and UV-B wavelength bands were presented to a variety of flowering plants to partly restore those wavelengths filtered out by greenhouse glass. In no tested plant did the supplementary ultraviolet radiation enhance floral anthocyanin content. Supplementary UV radiation has no economic value in greenhouse production of flowering plants. (author)

  4. 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)

  5. UV-LED Curing Efficiency of Wood Coatings

    OpenAIRE

    Véronic Landry; Pierre Blanchet; Gabrielle Boivin; Jean-François Bouffard; Mirela Vlad

    2015-01-01

    Ultraviolet light emitting diodes (UV-LEDs) have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerf...

  6. Additive effects of ultraviolet radiation

    International Nuclear Information System (INIS)

    Cullen, A.P.

    1980-01-01

    A xenon-mercury high pressure lamp and a double monochromator were used to produce ultraviolet (uv) radiation at 295 nm. Pigmented rabbit eyes were irradiated and evaluated by slitlamp biomicroscopy. Corneal threshold (Hc) was 0.05 J.cm-2 and lens threshold (hL) was 0.75 J.cm-2. Other eyes were irradiated with 2 Hc and evaluated from 4 to 24 h at 4 h intervals. Corneal damage was only greater than that expected from a single Hc exposure if the separation between the two Hc exposures did not exceed 8 h. The most repeatable and reliable corneal response to these levels of uv was the development of corneal epithelial granules

  7. Ultraviolet, Visible, and Fluorescence Spectroscopy

    Science.gov (United States)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  8. The high-resolution extraterrestrial solar spectrum (QASUMEFTS determined from ground-based solar irradiance measurements

    Directory of Open Access Journals (Sweden)

    J. Gröbner

    2017-09-01

    Full Text Available A high-resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance (SSI over the wavelength range from 300 to 500 nm using the Langley-plot technique. The measurements were obtained at the Izaña Atmospheric Research Centre from the Agencia Estatal de Meteorología, Tenerife, Spain, during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS was combined from medium-resolution (bandpass of 0.86 nm measurements of the QASUME (Quality Assurance of Spectral Ultraviolet Measurements in Europe spectroradiometer in the wavelength range from 300 to 500 nm and high-resolution measurements (0.025 nm from a Fourier transform spectroradiometer (FTS over the wavelength range from 305 to 380 nm. The Kitt Peak solar flux atlas was used to extend this high-resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere gave very good agreements in some cases, while in some other cases discrepancies of up to 5 % were observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

  9. Monitoring Hydraulic Fracturing Using Ground-Based Controlled Source Electromagnetics

    Science.gov (United States)

    Hickey, M. S.; Trevino, S., III; Everett, M. E.

    2017-12-01

    Hydraulic fracturing allows hydrocarbon production in low permeability formations. Imaging the distribution of fluid used to create a hydraulic fracture can aid in the characterization of fracture properties such as extent of plume penetration as well as fracture azimuth and symmetry. This could contribute to improving the efficiency of an operation, for example, in helping to determine ideal well spacing or the need to refracture a zone. A ground-based controlled-source electromagnetics (CSEM) technique is ideal for imaging the fluid due to the change in field caused by the difference in the conductive properties of the fluid when compared to the background. With advances in high signal to noise recording equipment, coupled with a high-power, broadband transmitter we can show hydraulic fracture extent and azimuth with minimal processing. A 3D finite element code is used to model the complete well casing along with the layered subsurface. This forward model is used to optimize the survey design and isolate the band of frequencies with the best response. In the field, the results of the modeling are also used to create a custom pseudorandom numeric (PRN) code to control the frequencies transmitted through a grounded dipole source. The receivers record the surface voltage across two grounded dipoles, one parallel and one perpendicular to the transmitter. The data are presented as the displays of amplitude ratios across several frequencies with the associated spatial information. In this presentation, we show multiple field results in multiple basins in the United States along with the CSEM theory used to create the survey designs.

  10. OBSERVATIONAL SELECTION EFFECTS WITH GROUND-BASED GRAVITATIONAL WAVE DETECTORS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Yu; Holz, Daniel E. [University of Chicago, Chicago, Illinois 60637 (United States); Essick, Reed; Vitale, Salvatore; Katsavounidis, Erik [LIGO, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2017-01-20

    Ground-based interferometers are not perfect all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean, and as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources’ right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO’s observations and electromagnetic (EM) follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over 80% of the localization probability, while mid-latitudes will access closer to 70%. Facilities located near the two LIGO sites can observe sources closer to their zenith than their analogs in the south, but the average observation will still be no closer than 44° from zenith. We also find that observatories in Africa or the South Atlantic will wait systematically longer before they can begin observing compared to the rest of the world; though, there is a preference for longitudes near the LIGOs. These effects, along with knowledge of the LIGO antenna pattern, can inform EM follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  11. Project management for complex ground-based instruments: MEGARA plan

    Science.gov (United States)

    García-Vargas, María. Luisa; Pérez-Calpena, Ana; Gil de Paz, Armando; Gallego, Jesús; Carrasco, Esperanza; Cedazo, Raquel; Iglesias, Jorge

    2014-08-01

    The project management of complex instruments for ground-based large telescopes is a challenge itself. A good management is a clue for project success in terms of performance, schedule and budget. Being on time has become a strict requirement for two reasons: to assure the arrival at the telescope due to the pressure on demanding new instrumentation for this first world-class telescopes and to not fall in over-costs. The budget and cash-flow is not always the expected one and has to be properly handled from different administrative departments at the funding centers worldwide distributed. The complexity of the organizations, the technological and scientific return to the Consortium partners and the participation in the project of all kind of professional centers working in astronomical instrumentation: universities, research centers, small and large private companies, workshops and providers, etc. make the project management strategy, and the tools and procedures tuned to the project needs, crucial for success. MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is a facility instrument of the 10.4m GTC (La Palma, Spain) working at optical wavelengths that provides both Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) capabilities at resolutions in the range R=6,000-20,000. The project is an initiative led by Universidad Complutense de Madrid (Spain) in collaboration with INAOE (Mexico), IAA-CSIC (Spain) and Universidad Politécnica de Madrid (Spain). MEGARA is being developed under contract with GRANTECAN.

  12. OBSERVATIONAL SELECTION EFFECTS WITH GROUND-BASED GRAVITATIONAL WAVE DETECTORS

    International Nuclear Information System (INIS)

    Chen, Hsin-Yu; Holz, Daniel E.; Essick, Reed; Vitale, Salvatore; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfect all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean, and as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources’ right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO’s observations and electromagnetic (EM) follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over 80% of the localization probability, while mid-latitudes will access closer to 70%. Facilities located near the two LIGO sites can observe sources closer to their zenith than their analogs in the south, but the average observation will still be no closer than 44° from zenith. We also find that observatories in Africa or the South Atlantic will wait systematically longer before they can begin observing compared to the rest of the world; though, there is a preference for longitudes near the LIGOs. These effects, along with knowledge of the LIGO antenna pattern, can inform EM follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  13. Simulating the Performance of Ground-Based Optical Asteroid Surveys

    Science.gov (United States)

    Christensen, Eric J.; Shelly, Frank C.; Gibbs, Alex R.; Grauer, Albert D.; Hill, Richard E.; Johnson, Jess A.; Kowalski, Richard A.; Larson, Stephen M.

    2014-11-01

    We are developing a set of asteroid survey simulation tools in order to estimate the capability of existing and planned ground-based optical surveys, and to test a variety of possible survey cadences and strategies. The survey simulator is composed of several layers, including a model population of solar system objects and an orbital integrator, a site-specific atmospheric model (including inputs for seeing, haze and seasonal cloud cover), a model telescope (with a complete optical path to estimate throughput), a model camera (including FOV, pixel scale, and focal plane fill factor) and model source extraction and moving object detection layers with tunable detection requirements. We have also developed a flexible survey cadence planning tool to automatically generate nightly survey plans. Inputs to the cadence planner include camera properties (FOV, readout time), telescope limits (horizon, declination, hour angle, lunar and zenithal avoidance), preferred and restricted survey regions in RA/Dec, ecliptic, and Galactic coordinate systems, and recent coverage by other asteroid surveys. Simulated surveys are created for a subset of current and previous NEO surveys (LINEAR, Pan-STARRS and the three Catalina Sky Survey telescopes), and compared against the actual performance of these surveys in order to validate the model’s performance. The simulator tracks objects within the FOV of any pointing that were not discovered (e.g. too few observations, too trailed, focal plane array gaps, too fast or slow), thus dividing the population into “discoverable” and “discovered” subsets, to inform possible survey design changes. Ongoing and future work includes generating a realistic “known” subset of the model NEO population, running multiple independent simulated surveys in coordinated and uncoordinated modes, and testing various cadences to find optimal strategies for detecting NEO sub-populations. These tools can also assist in quantifying the efficiency of novel

  14. Foundation Investigation for Ground Based Radar Project-Kwajalein Island, Marshall Islands

    Science.gov (United States)

    1990-04-01

    iL_ COPY MISCELLANEOUS PAPER GL-90-5 i iFOUNDATION INVESTIGATION FOR GROUND BASED RADAR PROJECT--KWAJALEIN ISLAND, MARSHALL ISLANDS by Donald E...C!assification) Foundatioa Investigation for Ground Based Radar Project -- Kwajalein Island, Marshall Islands 12. PERSONAL AUTHOR(S) Yule, Donald E...investigation for the Ground Based Radar Project -- Kwajalein Island, Marshall Islands , are presented.- eophysical tests comprised of surface refrac- tion

  15. Long term landslide monitoring with Ground Based SAR

    Science.gov (United States)

    Monserrat, Oriol; Crosetto, Michele; Luzi, Guido; Gili, Josep; Moya, Jose; Corominas, Jordi

    2014-05-01

    In the last decade, Ground-Based (GBSAR) has proven to be a reliable microwave Remote Sensing technique in several application fields, especially for unstable slopes monitoring. GBSAR can provide displacement measurements over few squared kilometres areas and with a very high spatial and temporal resolution. This work is focused on the use of GBSAR technique for long term landslide monitoring based on a particular data acquisition configuration, which is called discontinuous GBSAR (D-GBSAR). In the most commonly used GBSAR configuration, the radar is left installed in situ, acquiring data periodically, e.g. every few minutes. Deformations are estimated by processing sets of GBSAR images acquired during several weeks or months, without moving the system. By contrast, in the D-GBSAR the radar is installed and dismounted at each measurement campaign, revisiting a given site periodically. This configuration is useful to monitor slow deformation phenomena. In this work, two alternative ways for exploiting the D-GBSAR technique will be presented: the DInSAR technique and the Amplitude based Technique. The former is based on the exploitation of the phase component of the acquired SAR images and it allows providing millimetric precision on the deformation estimates. However, this technique presents several limitations like the reduction of measurable points with an increase in the period of observation, the ambiguous nature of the phase measurements, and the influence of the atmospheric phase component that can make it non applicable in some cases, specially when working in natural environments. The second approach, that is based on the use of the amplitude component of GB-SAR images combined with a image matching technique, will allow the estimation of the displacements over specific targets avoiding two of the limitations commented above: the phase unwrapping and atmosphere contribution but reducing the deformation measurement precision. Two successful examples of D

  16. 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

  17. Field emission characteristics of ZnO nanoneedle array cell under ultraviolet irradiation

    International Nuclear Information System (INIS)

    Lee, Woong; Jeong, Min-Chang; Kim, Min Jun; Myoung, Jae-Min

    2007-01-01

    Field emission (FE) behaviours of ZnO nanoneedle array under ultraviolet (UV) irradiation have been investigated. UV irradiation noticeably stabilized the FE behaviours. Modifications in the tunnelling barrier height and effective aspect ratio due to the oxygen-related surface species, which can be desorbed by UV irradiation, are supposed to be responsible for these observations

  18. Potential of ultraviolet widefield imaging and multiphoton microscopy for analysis of dehydroergosterol in cellular membranes

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Brewer, Jonathan R.; Bagatolli, Luis

    2011-01-01

    Dehydroergosterol (DHE) is an intrinsically fluorescent sterol with absorption/emission in the ultraviolet (UV) region and biophysical properties similar to those of cholesterol. We compared the potential of UV-sensitive low-light-level wide-field (UV-WF) imaging with that of multiphoton (MP) exc...

  19. A HOT COMPANION TO A BLUE STRAGGLER IN NGC 188 AS REVEALED BY THE ULTRA-VIOLET IMAGING TELESCOPE (UVIT) ON ASTROSAT

    Energy Technology Data Exchange (ETDEWEB)

    Subramaniam, Annapurni; Sindhu, N.; Tandon, S. N.; Rao, N. Kameswara; George, K.; Mohan, R.; Murthy, J.; Sankarasubramanian, K.; Stalin, C. S.; Sutaria, F.; Mondal, C.; Sahu, S. [Indian Institute of Astrophysics, Koramangala II Block, Bangalore-560034 (India); Postma, J. [University of Calgary, Calgary, Alberta (Canada); Côté, Patrick; Hutchings, J. B. [National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Ghosh, S. K. [National Centre for Radio Astrophysics, Pune (India); Girish, V., E-mail: purni@iiap.res.in [ISRO Satellite Centre, HAL Airport Road, Bangalore 560017 (India)

    2016-12-20

    We present early results from the Ultra-Violet Imaging Telescope (UVIT) on board the ASTROSAT observatory. We report the discovery of a hot companion associated with one of the blue straggler stars (BSSs) in the old open cluster, NGC 188. Using fluxes measured in four filters in UVIT’s far-UV (FUV) channel, and two filters in the near-UV (NUV) channel, we have constructed the spectral energy distribution (SED) of the star WOCS-5885, after combining with flux measurements from GALEX , Ultraviolet Imaging Telescope, Ultraviolet Optical Telescope, SPITZER , WISE , and several ground-based facilities. The resulting SED spans a wavelength range of 0.15 μ m to 7.8 μ m. This object is found to be one of the brightest FUV sources in the cluster. An analysis of the SED reveals the presence of two components. The cooler component is found to have a temperature of 6000 ± 150 K, confirming that it is a BSS. Assuming it to be a main-sequence star, we estimate its mass to be ∼1.1–1.2 M {sub ⊙}. The hotter component, with an estimated temperature of 17,000 ± 500 K, has a radius of ∼ 0.6 R {sub ⊙} and L ∼30 L {sub ⊙}. Bigger and more luminous than a white dwarf, yet cooler than a sub-dwarf, we speculate that it is a post-AGB/HB star that has recently transferred its mass to the BSS, which is known to be a rapid rotator. This binary system, which is the first BSS with a post-AGB/HB companion identified in an open cluster, is an ideal laboratory to study the process of BSS formation via mass transfer.

  20. A HOT COMPANION TO A BLUE STRAGGLER IN NGC 188 AS REVEALED BY THE ULTRA-VIOLET IMAGING TELESCOPE (UVIT) ON ASTROSAT

    International Nuclear Information System (INIS)

    Subramaniam, Annapurni; Sindhu, N.; Tandon, S. N.; Rao, N. Kameswara; George, K.; Mohan, R.; Murthy, J.; Sankarasubramanian, K.; Stalin, C. S.; Sutaria, F.; Mondal, C.; Sahu, S.; Postma, J.; Côté, Patrick; Hutchings, J. B.; Ghosh, S. K.; Girish, V.

    2016-01-01

    We present early results from the Ultra-Violet Imaging Telescope (UVIT) on board the ASTROSAT observatory. We report the discovery of a hot companion associated with one of the blue straggler stars (BSSs) in the old open cluster, NGC 188. Using fluxes measured in four filters in UVIT’s far-UV (FUV) channel, and two filters in the near-UV (NUV) channel, we have constructed the spectral energy distribution (SED) of the star WOCS-5885, after combining with flux measurements from GALEX , Ultraviolet Imaging Telescope, Ultraviolet Optical Telescope, SPITZER , WISE , and several ground-based facilities. The resulting SED spans a wavelength range of 0.15 μ m to 7.8 μ m. This object is found to be one of the brightest FUV sources in the cluster. An analysis of the SED reveals the presence of two components. The cooler component is found to have a temperature of 6000 ± 150 K, confirming that it is a BSS. Assuming it to be a main-sequence star, we estimate its mass to be ∼1.1–1.2 M _⊙. The hotter component, with an estimated temperature of 17,000 ± 500 K, has a radius of ∼ 0.6 R _⊙ and L ∼30 L _⊙. Bigger and more luminous than a white dwarf, yet cooler than a sub-dwarf, we speculate that it is a post-AGB/HB star that has recently transferred its mass to the BSS, which is known to be a rapid rotator. This binary system, which is the first BSS with a post-AGB/HB companion identified in an open cluster, is an ideal laboratory to study the process of BSS formation via mass transfer.

  1. Superhydrophobic Polyimide via Ultraviolet Photooxidation: The Evolution of Surface Morphology and Hydrophobicity under Different Ultraviolet Intensities

    Directory of Open Access Journals (Sweden)

    Hongyu Gu

    2015-01-01

    Full Text Available Ultraviolet (UV photooxidation has recently been developed to fabricate superhydrophobic polyimide (PI films in combination with fluoroalkylsilane modification. However, it remains unclear whether the surface morphology and hydrophobicity are sensitive to technical parameters such as UV intensity and radiation environment. Herein, we focus on the effects of UV intensity on PI surface structure and wettability to gain comprehensive understanding and more effective control of this technology. Scanning electron microscopy (SEM and atomic force microscopy (AFM results showed that UV intensity governed the evolutionary pattern of surface morphology: lower UV intensity (5 mW/cm2 facilitated in-plane expansion of dendritic protrusions while stronger UV (10 and 15 mW/cm2 encouraged localized growth of protrusions in a piling-up manner. Surface roughness and hydrophobicity maximized at the intensity of 10 mW/cm2, as a consequence of the slowed horizontal expansion and preferred vertical growth of the protrusions when UV intensity increased. Based on these results, the mechanism that surface micro/nanostructures developed in distinct ways when exposed to different UV intensities was proposed. Though superhydrophobicity (water contact angle larger than 150° can be achieved at UV intensity not less than 10 mW/cm2, higher intensity decreased the effectiveness. Therefore, the UV photooxidation under 10 mW/cm2 for 72 h is recommended to fabricate superhydrophobic PI films.

  2. Pathways of ultraviolet mutability in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Lemontt, J.F.

    1977-01-01

    Non-allelic mutants of Saccharomyces cerevisiae with reduced capacity for ultraviolet light (UV)-induced forward mutation from CAN1 to can1 were assigned to seven distinct genetic loci, each with allele designations umr1-1, umr2-1, ..., umr7-1 to indicate UV mutation resistance. None conferred a great deal of UV sensitivity. When assayed on yeast extract-peptone-dextrose complex growth agar, umr1, umr3, and umr7 were the most UV-sensitive. When assayed on synthetic agar lacking arginine, however, umr3 was the most UV-sensitive. All strains carrying each of the seven umr genes exhibited varying degrees of defective UV mutability, compact with wild types. Normal UV revertibility of three different alleles was observed in strains carrying either umr4, umr5, umr6, or umr7. Five a/α homozygous umr diploids failed to sporulate. One of these, umr7, blocked normal secretion of alpha hormone in α segregants and could not conjugate with a strains. The phenotypes of umr mutants are consistent with the existence of branched UV mutation pathways of different specificity

  3. Impact of ultraviolet radiation on humans

    International Nuclear Information System (INIS)

    Cesarini, J.P.

    2001-01-01

    Solar radiation, including its ultraviolet (UV) components is a key factor in life on Earth. While small quantities of UV are beneficial for people (for example, through the production of vitamin D), the considerable amount to which people sometimes expose themselves may have extremely noxious effects including actinic erythema, sunburn, photo-induced diseases, photo-worsened diseases, actinic ageing and skin cancers. Since the last century, human exposure to UV has increased either by social-behaviour modifications, or by anthropogenic disruption to the environment through, among other things, industrial development. The World Health Organisation's (WHO) INTERSUN programme has several components: action for reconstruction of the ozone layer through, for example, preventing dumping of chlorofluorocarbons; creation and popularisation of a global UV index; prevention campaigns underlining the risks from UV exposure including dissemination of information to daily newspapers. These are all aimed at reducing the amount of UV radiation that people receive. In addition the WHO advises against exposure to UV artificial sources to reduce overall the quantity of UV received. (author)

  4. Impact of ultraviolet radiation on humans

    Energy Technology Data Exchange (ETDEWEB)

    Cesarini, J.P. [Laboratoire de Recherche sur les Tumeurs de la Peau Humaine, INSERM, Paris (France)

    2001-07-01

    Solar radiation, including its ultraviolet (UV) components is a key factor in life on Earth. While small quantities of UV are beneficial for people (for example, through the production of vitamin D), the considerable amount to which people sometimes expose themselves may have extremely noxious effects including actinic erythema, sunburn, photo-induced diseases, photo-worsened diseases, actinic ageing and skin cancers. Since the last century, human exposure to UV has increased either by social-behaviour modifications, or by anthropogenic disruption to the environment through, among other things, industrial development. The World Health Organisation's (WHO) INTERSUN programme has several components: action for reconstruction of the ozone layer through, for example, preventing dumping of chlorofluorocarbons; creation and popularisation of a global UV index; prevention campaigns underlining the risks from UV exposure including dissemination of information to daily newspapers. These are all aimed at reducing the amount of UV radiation that people receive. In addition the WHO advises against exposure to UV artificial sources to reduce overall the quantity of UV received. (author)

  5. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    International Nuclear Information System (INIS)

    Brown, Peter J.

    2014-01-01

    We present and discuss the ultraviolet (UV)/optical photometric light curves and absolute magnitudes of the Type Ia supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observed—more than a factor of 10 brighter than normal SNe Ia in the mid-ultraviolet. We find that the UV/optical brightness and broad light curve evolution can be modeled with additional flux from the shock of the ejecta hitting a relatively large red giant companion separated by 6 × 10 13 cm. However, the post-maximum behavior of other UV-bright SNe Ia can also be modeled in a similar manner, including objects with UV spectroscopy or pre-maximum photometry which is inconsistent with this model. This suggests that similar UV luminosities can be intrinsic or caused by other forms of shock interaction. The high velocities reported for SN 2011de make it distinct from the UV-bright ''super-Chandrasekhar'' SNe Ia and the NUV-blue group of normal SNe Ia. SN 2011de is an extreme example of the UV variations in SNe Ia

  6. A detrimental soil disturbance prediction model for ground-based timber harvesting

    Science.gov (United States)

    Derrick A. Reeves; Matthew C. Reeves; Ann M. Abbott; Deborah S. Page-Dumroese; Mark D. Coleman

    2012-01-01

    Soil properties and forest productivity can be affected during ground-based harvest operations and site preparation. The degree of impact varies widely depending on topographic features and soil properties. Forest managers who understand site-specific limits to ground-based harvesting can alter harvest method or season to limit soil disturbance. To determine the...

  7. Evaluation of tropospheric and stratospheric ozone trends over Western Europe from ground-based FTIR network observations

    Directory of Open Access Journals (Sweden)

    C. Vigouroux

    2008-12-01

    Full Text Available Within the European project UFTIR (Time series of Upper Free Troposphere observations from an European ground-based FTIR network, six ground-based stations in Western Europe, from 79° N to 28° N, all equipped with Fourier Transform infrared (FTIR instruments and part of the Network for the Detection of Atmospheric Composition Change (NDACC, have joined their efforts to evaluate the trends of several direct and indirect greenhouse gases over the period 1995–2004. The retrievals of CO, CH4, C2H6, N2O, CHClF2, and O3 have been optimized. Using the optimal estimation method, some vertical information can be obtained in addition to total column amounts. A bootstrap resampling method has been implemented to determine annual partial and total column trends for the target gases. The present work focuses on the ozone results. The retrieved time series of partial and total ozone columns are validated with ground-based correlative data (Brewer, Dobson, UV-Vis, ozonesondes, and Lidar. The observed total column ozone trends are in agreement with previous studies: 1 no total column ozone trend is seen at the lowest latitude station Izaña (28° N; 2 slightly positive total column trends are seen at the two mid-latitude stations Zugspitze and Jungfraujoch (47° N, only one of them being significant; 3 the highest latitude stations Harestua (60° N, Kiruna (68° N and Ny-Ålesund (79° N show significant positive total column trends. Following the vertical information contained in the ozone FTIR retrievals, we provide partial columns trends for the layers: ground-10 km, 10–18 km, 18–27 km, and 27–42 km, which helps to distinguish the contributions from dynamical and chemical changes on the total column ozone trends. We obtain no statistically significant trends in the ground-10 km layer for five out of the six ground-based stations. We find significant positive trends for the lowermost

  8. Eight-component retrievals from ground-based MAX-DOAS observations

    Directory of Open Access Journals (Sweden)

    H. Irie

    2011-06-01

    Full Text Available We attempt for the first time to retrieve lower-tropospheric vertical profile information for 8 quantities from ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS observations. The components retrieved are the aerosol extinction coefficients at two wavelengths, 357 and 476 nm, and NO2, HCHO, CHOCHO, H2O, SO2, and O3 volume mixing ratios. A Japanese MAX-DOAS profile retrieval algorithm, version 1 (JM1, is applied to observations performed at Cabauw, the Netherlands (51.97° N, 4.93° E, in June–July 2009 during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI. Of the retrieved profiles, we focus here on the lowest-layer data (mean values at altitudes 0–1 km, where the sensitivity is usually highest owing to the longest light path. In support of the capability of the multi-component retrievals, we find reasonable overall agreement with independent data sets, including a regional chemical transport model (CHIMERE and in situ observations performed near the surface (2–3 m and at the 200-m height level of the tall tower in Cabauw. Plumes of enhanced HCHO and SO2 were likely affected by biogenic and ship emissions, respectively, and an improvement in their emission strengths is suggested for better agreement between CHIMERE simulations and MAX-DOAS observations. Analysis of air mass factors indicates that the horizontal spatial representativeness of MAX-DOAS observations is about 3–15 km (depending mainly on aerosol extinction, comparable to or better than the spatial resolution of current UV-visible satellite observations and model calculations. These demonstrate that MAX-DOAS provides multi-component data useful for the evaluation of satellite observations and model calculations and can play an important role in bridging different data sets having different spatial resolutions.

  9. Biosensors for EVA: Improved Instrumentation for Ground-based Studies

    Science.gov (United States)

    Soller, B.; Ellerby, G.; Zou, F.; Scott, P.; Jin, C.; Lee, S. M. C.; Coates, J.

    2010-01-01

    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group has developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO 2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO 2 on the leg during cycling. Our NSBRI project has 4 objectives: (1) increase the accuracy of the metabolic rate calculation through improved prediction of stroke volume; (2) investigate the relative contributions of calf and thigh oxygen consumption to metabolic rate calculation for walking and running; (3) demonstrate that the NIRS-based noninvasive metabolic rate methodology is sensitive enough to detect decrement in VO 2 in a space analog; and (4) improve instrumentation to allow testing within a spacesuit. Over the past year we have made progress on all four objectives, but the most significant progress was made in improving the instrumentation. The NIRS system currently in use at JSC is based on fiber optics technology. Optical fiber bundles are used to deliver light from a light source in the monitor to the patient, and light reflected back from the patient s muscle to the monitor for spectroscopic analysis. The fiber optic cables are large and fragile, and there is no way to get them in and out of the test spacesuit used for ground-based studies. With complimentary funding from the US Army, we undertook a complete redesign of the sensor and control electronics to build a novel system small enough to be used within the spacesuit and portable enough to be used by a combat medic. In the new system the filament lamp used in the fiber optic system was replaced with a novel broadband near infrared

  10. UV ACTIVATION OF RECEPTOR TYROSINE KINASE-ACTIVITY

    NARCIS (Netherlands)

    COFFER, PJ; BURGERING, BMT; PEPPELENBOSCH, MP; BOS, JL; KRUIJER, W

    1995-01-01

    The exposure of mammalian cells to ultraviolet radiation (UV) may lead to DNA damage resulting in mutation and thus possibly cancer, while irradiation can further act as a potent tumour promoter. In addition UV induces p21ras-mediated signalling leading to activation of transcription factors such as

  11. 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...

  12. THE ULTRAVIOLET-TO-MID-INFRARED SPECTRAL ENERGY DISTRIBUTION OF WEAK EMISSION LINE QUASARS

    International Nuclear Information System (INIS)

    Lane, Ryan A.; Shemmer, Ohad; Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Anderson, Scott F.; Brandt, W. N.; Schneider, Donald P.; Plotkin, Richard M.; Richards, Gordon T.; Strauss, Michael A.

    2011-01-01

    We present Spitzer Space Telescope photometry of 18 Sloan Digital Sky Survey (SDSS) quasars at 2.7 ≤ z ≤ 5.9 which have weak or undetectable high-ionization emission lines in their rest-frame ultraviolet (UV) spectra (hereafter weak-lined quasars, or WLQs). The Spitzer data are combined with SDSS spectra and ground-based, near-infrared (IR) photometry of these sources to produce a large inventory of spectral energy distributions (SEDs) of WLQs across the rest-frame ∼0.1-5 μm spectral band. The SEDs of our sources are inconsistent with those of BL Lacertae objects which are dominated by synchrotron emission due to a jet aligned close to our line of sight, but are consistent with the SED of ordinary quasars with similar luminosities and redshifts that exhibit a near-to-mid-IR 'bump', characteristic of hot dust emission. This indicates that broad emission lines in WLQs are intrinsically weak, rather than suffering continuum dilution from a jet, and that such sources cannot be selected efficiently from traditional photometric surveys.

  13. THE ULTRAVIOLET-TO-MID-INFRARED SPECTRAL ENERGY DISTRIBUTION OF WEAK EMISSION LINE QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Ryan A.; Shemmer, Ohad [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Diamond-Stanic, Aleksandar M. [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States); Fan Xiaohui [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Brandt, W. N.; Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Plotkin, Richard M. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam (Netherlands); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Strauss, Michael A., E-mail: RyanLane@my.unt.edu, E-mail: ohad@unt.edu [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)

    2011-12-20

    We present Spitzer Space Telescope photometry of 18 Sloan Digital Sky Survey (SDSS) quasars at 2.7 {<=} z {<=} 5.9 which have weak or undetectable high-ionization emission lines in their rest-frame ultraviolet (UV) spectra (hereafter weak-lined quasars, or WLQs). The Spitzer data are combined with SDSS spectra and ground-based, near-infrared (IR) photometry of these sources to produce a large inventory of spectral energy distributions (SEDs) of WLQs across the rest-frame {approx}0.1-5 {mu}m spectral band. The SEDs of our sources are inconsistent with those of BL Lacertae objects which are dominated by synchrotron emission due to a jet aligned close to our line of sight, but are consistent with the SED of ordinary quasars with similar luminosities and redshifts that exhibit a near-to-mid-IR 'bump', characteristic of hot dust emission. This indicates that broad emission lines in WLQs are intrinsically weak, rather than suffering continuum dilution from a jet, and that such sources cannot be selected efficiently from traditional photometric surveys.

  14. Global Solar UV Index (invited paper)

    International Nuclear Information System (INIS)

    Repacholi, M.H.

    2000-01-01

    Excessive solar ultraviolet (UV) radiation exposure produces a significant burden of disease to the skin, eyes and immune system. Effective programmes for the reduction of UV exposure are needed to reduce this disease burden and the associated health care costs. The UV index is seen as an effective tool for communicating important protection information to the public through its use in media news and weather information. The index is described and it is suggested that universally common messages should be associated with its ranges. (author)

  15. RPC industries - UV and EB equipment manufacturers

    International Nuclear Information System (INIS)

    Rodrigues, A.M.

    1987-01-01

    RPC Industries has been manufacturing electron beam and ultraviolet equipment for the industrial processing of materials for more than 15 years. RPC maintains its headquarters and electron processor manufacturing plant in Hayward, California. UV equipment is made in the company's plant near Chicago. Sales offices are maintained in New York, Illinois, and California in the USA, and in Germany, Japan, Australia, Italy, Israel, and Sweden. Complete testing and pilot facilities are available in Hayward (EB) and near Chicago (UV). Described below are the basic system components, applications and advantages of RPC's UV and EB systems. (orig.)

  16. Protective mechanisms and acclimation to solar ultraviolet-B radiation in Oenothera stricta

    Science.gov (United States)

    Robberecht, R.; Caldwell, M. M.

    1981-01-01

    Plant adaptations ameliorating or repairing the damaging effects of ultraviolet-B (UV-B) radiation on plant tissue were investigated. The degree of phenotype plasticity in UV protective mechanisms and acclimation in relation to the natural solar UV-B radiation flux and in an enhanced UV-B irradiance environment was also examined. Mechanisms by which plants avoid radiation, adaptations altering the path of radiation incident on the leaf, and repair processes were considered. Attenuation of UV-B by tissues, UV-B irradiation into the leaf, and the effects of UV-B on photosynthesis were investigated.

  17. Protective mechanisms and acclimation to solar ultraviolet-b radiation in oenothera stricta. Final report

    International Nuclear Information System (INIS)

    Robberecht, R.; Caldwell, M.M.

    1981-12-01

    Plant adaptations ameliorating or repairing the damaging effects of ultraviolet-B (UV-B) radiation on plant tissue were investigated. The degree of phenotype plasticity in UV protective mechanisms and acclimation in relation to the natural solar UV-B radiation flux and in an enhanced UV-B irradiance environment was also examined. Mechanisms by which plants avoid radiation, adaptations altering the path of radiation incident on the leaf, and repair processes were considered. Attenuation of UV-B by tissues, UV-B irradiation into the leaf, and the effects of UV-B on photosynthesis were investigated

  18. Photomorphogenic responses to ultraviolet-B light.

    Science.gov (United States)

    Jenkins, Gareth I

    2017-11-01

    Exposure to ultraviolet B (UV-B) light regulates numerous aspects of plant metabolism, morphology and physiology through the differential expression of hundreds of genes. Photomorphogenic responses to UV-B are mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8). Considerable progress has been made in understanding UVR8 action: the structural basis of photoreceptor function, how interaction with CONSTITUTIVELY PHOTOMORPHOGENIC 1 initiates signaling and how REPRESSOR OF UV-B PHOTOMORPHOGENESIS proteins negatively regulate UVR8 action. In addition, recent research shows that UVR8 mediates several responses through interaction with other signaling pathways, in particular auxin signaling. Nevertheless, many aspects of UVR8 action remain poorly understood. Most research to date has been undertaken with Arabidopsis, and it is important to explore the functions and regulation of UVR8 in diverse plant species. Furthermore, it is essential to understand how UVR8, and UV-B signaling in general, regulates processes under natural growth conditions. Ultraviolet B regulates the expression of many genes through UVR8-independent pathways, but the activity and importance of these pathways in plants growing in sunlight are poorly understood. © 2017 John Wiley & Sons Ltd.

  19. STELLAR ACTIVITY IN THE BROADBAND ULTRAVIOLET

    International Nuclear Information System (INIS)

    Findeisen, K.; Hillenbrand, L.; Soderblom, D.

    2011-01-01

    The completion of the GALEX All-Sky Survey in the ultraviolet allows activity measurements to be acquired for many more stars than is possible with the limited sensitivity of ROSAT or the limited sky coverage of Chandra, XMM, or spectroscopic surveys for line emission in the optical or ultraviolet. We have explored the use of GALEX photometry as an activity indicator, using stars within 50 pc as a calibration sample representing the field and in selected nearby associations representing the youngest stages of stellar evolution. We present preliminary relations between UV flux and the optical activity indicator R' HK and between UV flux and age. We demonstrate that far-UV (FUV, 1350-1780 A) excess flux is roughly proportional to R' HK . We also detect a correlation between near-UV (NUV, 1780-2830 A) flux and activity or age, but the effect is much more subtle, particularly for stars older than ∼0.5-1 Gyr. Both the FUV and NUV relations show large scatter, ∼0.2 mag when predicting UV flux, ∼0.18 dex when predicting R' HK , and ∼0.4 dex when predicting age. This scatter appears to be evenly split between observational errors in current state-of-the-art data and long-term activity variability in the sample stars.

  20. Polymer filters for ultraviolet-excited integrated fluorescence sensing

    International Nuclear Information System (INIS)

    Dandin, Marc; Abshire, Pamela; Smela, Elisabeth

    2012-01-01

    Optical filters for blocking ultraviolet (UV) light were fabricated by doping various polymer hosts with a UV absorbing chromophore. The polymers were polydimethylsiloxane (PDMS), a silicone elastomer frequently used in microfluidics, SU-8, a photopatternable epoxy, and Humiseal 1B66, an acrylic coating used for moisture protection of integrated circuits. The chromophore was 2-(2′-hydroxy-5′-methylphenyl) benzotriazole (BTA), which has a high extinction coefficient between 300 nm and 400 nm. We demonstrate filters 5 µm thick that exhibit high ultraviolet rejection (nearly −40 dB at 342 nm) yet pass visible light (near 0 dB above 400 nm), making them ideal for ultraviolet-excited fluorescence sensing within microsystems. The absorbance of the BTA depended on the host polymer. These filters are promising for integrated fluorescence spectroscopy in bioanalytical platforms because they can be patterned by dry etching, molding or exposure to ultraviolet light. (paper)

  1. Investigation of UV-LED Initiated Photopolymerisation of Bio-compatible HEMA

    OpenAIRE

    McDermott, Sharon

    2008-01-01

    Ultraviolet (UV) fluorescent lamps are widely used in photopolymerisation processes. However, there a number of disadvantages to these lamps, namely, their intensity varies over time and has to be constantly monitored. This thesis is concerned with the possibility of replacing these lamps with UV Light Emitting Diodes (UV-LEDs). A number of emission characteristics of both the fluorescent lamp and the UV-LEDs were measured and compared to ensure that the optical properties of the UV-LEDs were...

  2. A new UV-A/B protecting pigment in the terrestrial cyanobacterium Nostoc commune

    International Nuclear Information System (INIS)

    Scherer, S.; Chen, T.W.; Boeger, P.

    1988-01-01

    A new ultraviolet (UV)-A/B absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium Nostoc commune is described. The pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar UV radiation but only in low concentrations in laboratory cultures illuminated by artificial light without UV. Its experimental induction by UV as well as its capacity to efficiently protect Nostoc against UV radiation is reported

  3. Effect of ultraviolet illumination on metal oxide resistive memory

    KAUST Repository

    Duran Retamal, Jose Ramon

    2014-12-22

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

  4. Ultraviolet light induced refractive index structures in germanosilica

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    1997-01-01

    The focus of the research presented in this ph.d. thesis is refractive index structures photoinduced in germanonsilica waveguides with ultra-violet (UV) radiation. The physical mechanisms involved in photosensitivity and applications of a wide range of UV induced refractive index structures in both...... application of a scanning near-field optical microscope to obtain high resolution images of UV induced refractive index structures and by monitoring the dynamics of UV induced index changes and luminescence. During part of my ph.d. project I have worked at the National Institute of Standards and Technolgy...

  5. Effect of ultraviolet illumination on metal oxide resistive memory

    KAUST Repository

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

    2014-01-01

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

  6. Ambient ultraviolet radiation causes mortality in salamander eggs

    International Nuclear Information System (INIS)

    Blaustein, A.R.; Edmond, B.; Kiesecker, J.M.

    1995-01-01

    Previous research has shown that amphibian species have differential sensitivity to ultraviolet-B (UV-B) radiation. In some anuran species, ambient levels of UV-B cause mortality in embryonic stages and hatching success is significantly reduced. Projected increases in UV-B may affect an increasing number of species. The adverse effects of UV-B may eventually be manifested at the population level and may ultimately contribute to population declines. Using field experiments, we investigated the effects of ambient UV-B on salamander (Ambystoma gracile) embryos developing at natural oviposition sites. We show that the hatching success of eggs of A. gracile shielded from UV-B is significantly higher than those not shielded from UV-B. 27 refs., 1 fig

  7. UV Digital Imaging of Sulfur Dioxide Emissions: Enhancing the Technique With Empirical Corrections

    Science.gov (United States)

    Dalton, M. P.; Bluth, G. J.; Shannon, J. M.; Watson, I. M.

    2006-12-01

    SO2 emission measurements are an important component of monitoring volcanic processes, providing insight into the driving forces behind eruptions. Current spectrometric methods (COSPEC, DOAS) typically measure only a cross-section of the plume, which may not be representative of the actual emission flux, and coupled with the difficulty in determining wind speeds affecting the air mass, often leads to erratic SO2 flux values. In order to address these problems, we have developed a ground-based ultraviolet digital camera for the imaging and measurement of SO2 volcanic plumes. This camera improves on the spectrometric methods of SO2 observation by capturing a large portion of the plume in one measurement- a single image. The UV digital camera can also record multiple images every minute, producing a data set that is more comparable with other monitoring techniques. The UV digital camera has proven capable of imaging volcanic plumes under fairly demanding conditions, and determining SO2 fluxes that have roughly agreed with other SO2 measurement techniques. Initial field tests suggest that the data produced by the UV camera are significantly affected by atmospheric scattering. To better evaluate the errors and limitations associated with this new instrument, field experiments have been conducted to assess the effects that background sky brightness, meteorological conditions, and distance to the target have on the calculated SO2 concentrations and flux measurements. Our results will allow us to more accurately model and correct for changing atmospheric conditions and quantify the error associated with atmospheric background scattering. These corrections will make this remarkable new instrument a more accurate and valuable tool for monitoring volcanic emissions.

  8. Ultraviolet vision in birds: the importance of transparent eye media.

    Science.gov (United States)

    Lind, Olle; Mitkus, Mindaugas; Olsson, Peter; Kelber, Almut

    2014-01-07

    Ultraviolet (UV)-sensitive visual pigments are widespread in the animal kingdom but many animals, for example primates, block UV light from reaching their retina by pigmented lenses. Birds have UV-sensitive (UVS) visual pigments with sensitivity maxima around 360-373 nm (UVS) or 402-426 nm (violet-sensitive, VS). We describe how these pigments are matched by the ocular media transmittance in 38 bird species. Birds with UVS pigments have ocular media that transmit more UV light (wavelength of 50% transmittance, λ(T0.5), 323 nm) than birds with VS pigments (λ(T0.5), 358 nm). Yet, visual models predict that colour discrimination in bright light is mostly dependent on the visual pigment (UVS or VS) and little on the ocular media. We hypothesize that the precise spectral tuning of the ocular media is mostly relevant for detecting weak UV signals, e.g. in dim hollow-nests of passerines and parrots. The correlation between eye size and UV transparency of the ocular media suggests little or no lens pigmentation. Therefore, only small birds gain the full advantage from shifting pigment sensitivity from VS to UVS. On the other hand, some birds with VS pigments have unexpectedly low UV transmission of the ocular media, probably because of UV blocking lens pigmentation.

  9. Determination of ultraviolet filter activity on coconut oil cosmetic cream

    Science.gov (United States)

    Widiyati, Eni

    2017-08-01

    A research on determination of ultraviolet (UV) filter activity of cosmetic cream with coconut oil as raw material has been done. The cream was made by mixing the oil phase (coconut oil, stearic acid, lanolin and cetyl alcohol) at 70°C and the water phase (glycerin, aquadest and triethanolamine) at 70°C, while stirring until reached a temperature of 35°C. It was made also a cream with inorganic sunscreen TiO2 and organic sunscreen benzophenone-3 as a comparison. To study the UV filter activity, each cream was determined the UV absorption using UV spectrophotometer. The results show that cosmetic cream with coconut oil as raw material absorbs UV rays in the region of UV-C, whereas the cream with TiO2 absorbs the UV rays from UV-C to UV-A and cream with benzophenone-3 absorbs the UV rays from UV-B to UV-A region. This means that, the cosmetic cream with coconut oil as raw material has an activity as UV-C filter. If this cream is expected to have an activity as a sunscreen, it must be added an inorganic or organic sunscreen or a mixture of both as an active materials.

  10. Cosmetic and medical applications of ultraviolet radiation

    International Nuclear Information System (INIS)

    Diffey, B.L.

    1987-01-01

    The social desirability of a tanned skin is apparent and many people associate a bronzed body with good health and a sense of well-being. In Northern Europe and America the lack of long periods of sunshine has led to the establishment of the suntanning industry where artificial sources of ultraviolet radiation emitting almost entirely in the UV-A region supplement sunlight exposure

  11. Exoplanets -New Results from Space and Ground-based Surveys

    Science.gov (United States)

    Udry, Stephane

    The exploration of the outer solar system and in particular of the giant planets and their environments is an on-going process with the Cassini spacecraft currently around Saturn, the Juno mission to Jupiter preparing to depart and two large future space missions planned to launch in the 2020-2025 time frame for the Jupiter system and its satellites (Europa and Ganymede) on the one hand, and the Saturnian system and Titan on the other hand [1,2]. Titan, Saturn's largest satellite, is the only other object in our Solar system to possess an extensive nitrogen atmosphere, host to an active organic chemistry, based on the interaction of N2 with methane (CH4). Following the Voyager flyby in 1980, Titan has been intensely studied from the ground-based large telescopes (such as the Keck or the VLT) and by artificial satellites (such as the Infrared Space Observatory and the Hubble Space Telescope) for the past three decades. Prior to Cassini-Huygens, Titan's atmospheric composition was thus known to us from the Voyager missions and also through the explorations by the ISO. Our perception of Titan had thus greatly been enhanced accordingly, but many questions remained as to the nature of the haze surrounding the satellite and the composition of the surface. The recent revelations by the Cassini-Huygens mission have managed to surprise us with many discoveries [3-8] and have yet to reveal more of the interesting aspects of the satellite. The Cassini-Huygens mission to the Saturnian system has been an extraordinary success for the planetary community since the Saturn-Orbit-Insertion (SOI) in July 2004 and again the very successful probe descent and landing of Huygens on January 14, 2005. One of its main targets was Titan. Titan was revealed to be a complex world more like the Earth than any other: it has a dense mostly nitrogen atmosphere and active climate and meteorological cycles where the working fluid, methane, behaves under Titan conditions the way that water does on

  12. 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...

  13. Low doses of ultraviolet-B or ultraviolet-C radiation affect phytohormones in young pea plants

    International Nuclear Information System (INIS)

    Ivanov, S.; Azmi, A.; Prinsen, E.; Van Onckelen, H.; Alexieva, V.; Katerova, Z.

    2009-01-01

    Pea (cv. Scinado) seedlings were exposed to low doses of ultraviolet-B (UV-B; 4.4 and 13.3 kJ/square m/d) or UV-C (0.1 and 0.3 kJ/square m/d) radiation for 14 d. Aminocyclopropane carboxylic acid (ACC), indoleacetic acid (IAA) and abscisic acid (ABA) concentrations were quantified by gas chromatography coupled to mass spectrometry. The accumulation of ACC upon irradiation was dose-dependent. ABA conc. was reduced and IAA conc. increased upon UV-C treatment, whereas the UV-B doses used did not cause significant changes in ABA and IAA levels

  14. Ultraviolet light imaging technology and applications

    Science.gov (United States)

    Yokoi, Takane; Suzuki, Kenji; Oba, Koichiro

    1991-06-01

    Demands on the high-quality imaging in ultraviolet (UV) light region have been increasing recently, especially in fields such as forensic investigations, laser experiments, spent fuel identification, and so on. Important requirements on the UV imaging devices in such applications are high sensitivity, excellent solar blindness, and small image distortion, since the imaging of very weak UV images are usually carried out under natural sunlight or room illuminations and the image data have to be processed to produce useful two-dimensional quantitative data. A new photocathode has been developed to meet these requirements. It is specially made of RbTe on a sapphire window and its quantum efficiency is as high as 20% with the solar blindness of 10,000. The tube is specially designed to meet UV light optics and to minimize image distortion. It has an invertor type image intensifier tube structure and intensifies the incident UV light up to approximately 10,000 times. The distortion of the output image is suppressed less than 1.8%, because of a specially designed electron optic lens system. The device has shown excellent results in the observation of such objects as fingerprints and footprints in forensic investigations, the Cherenkov light produced by the spent fuels stored in a cooling water pool in the nuclear power station, and UV laser beam path in excimer laser experiments. Furthermore, many other applications of the UV light imaging will be expected in various fields such as semiconductors, cosmetics, and electrical power.

  15. The Ultraviolet Index: a useful tool.

    Science.gov (United States)

    Kinney, J P; Long, C S

    2000-09-01

    The Ultraviolet Index was developed in the United States in 1994 following successful use of ultraviolet (UV) alerts in other countries. This daily National Weather Service prediction is a calculation which integrates five data elements to yield the amount of UV radiation impacting the surface (1m2) at solar noon in 58 of the largest US population centers. This simple numeric prediction is then categorized by the Environmental Protection Agency into five "exposure levels" with protective actions recommended for each level. This information is disseminated through the media. Daily reminders seem to affect awareness and behavior in Canada, but US surveys indicate the need for better understanding through educational graphics. Comparing the UV Index to a precipitation prediction has merit in that it links a familiar daily prediction with implied appropriate protective measures. Graphics link the ideas that "when it rains it pours and when it shines it radiates." Beginning in schools, camps, and dermatology meetings, using the rain/shine analogy, a wider exposure to the Ultraviolet Index is proposed.

  16. Observations of the neutral atmosphere between 100 and 200 km using ARIA rocket-borne and ground-based instruments

    International Nuclear Information System (INIS)

    Hecht, J.H.; Christensen, A.B.; Gutierrez, D.J.

    1995-01-01

    The atmospheric response in the aurora (ARIA) rocket was launched at 1406 UT on March 3, 1992, from Poker Flat, Alaska, into a pulsating diffuse aurora; rocket-borne instruments included an eight-channel photometer, a far ultraviolet spectrometer, a 130.4-nm atomic oxygen resonance lamp, and two particle spectrometers covering the energy range of 1-400 eV and 10 eV to 20 keV. The photometer channels were isolated using narrow-band interference filters and included measurements of the strong permitted auroral emissions N 2 (337.1 nm), N 2 + (391.4 nm), and O I (844.6 nm). A ground-based photometer measured the premitted N 2 + (427.8 nm), the forbidden O I (630.0 nm), and the premitted O I (844.6 nm) emissions. The ground-based instrument was pointed in the magnetic zenith. Also, the rocket payload was pointed in the magnetic zenith from 100 to 200 km on the upleg. The data were analyzed using the Strickland electron transport code, and the rocket and ground-based results were found to be in good agreement regarding the inferred characteristic energy of the precipitating auroral flux and the composition of the neutral atmosphere during the rocket flight. In particular, it was found that the O/N 2 density ratio in the neutral atmosphere diminished during the auroral substorm, which started about 2 hours before the ARIA rocket flight. The data showed that there was about a 10-min delay between the onset of the substorm and the decrease of the O/N 2 density ratio. At the time of the ARIA flight this ratio had nearly returned to its presubstorm value. However, the data also showed that the O/N 2 density ratio did not recover to its presubstorm value until nearly 30 min after the particle and joule heating had subsided. Both the photometer and oxygen densities in the region above 130 km. The observed auroral brightness ratio B 337.1 /B 391.4 equaled 0.29 and was in agreement with other recent measurements

  17. Suborbital Reusable Launch Vehicles as an Opportunity to Consolidate and Calibrate Ground Based and Satellite Instruments

    Science.gov (United States)

    Papadopoulos, K.

    2014-12-01

    XCOR Aerospace, a commercial space company, is planning to provide frequent, low cost access to near-Earth space on the Lynx suborbital Reusable Launch Vehicle (sRLV). Measurements in the external vacuum environment can be made and can launch from most runways on a limited lead time. Lynx can operate as a platform to perform suborbital in situ measurements and remote sensing to supplement models and simulations with new data points. These measurements can serve as a quantitative link to existing instruments and be used as a basis to calibrate detectors on spacecraft. Easier access to suborbital data can improve the longevity and cohesiveness of spacecraft and ground-based resources. A study of how these measurements can be made on Lynx sRLV will be presented. At the boundary between terrestrial and space weather, measurements from instruments on Lynx can help develop algorithms to optimize the consolidation of ground and satellite based data as well as assimilate global models with new data points. For example, current tides and the equatorial electrojet, essential to understanding the Thermosphere-Ionosphere system, can be measured in situ frequently and on short notice. Furthermore, a negative-ion spectrometer and a Faraday cup, can take measurements of the D-region ion composition. A differential GPS receiver can infer the spatial gradient of ionospheric electron density. Instruments and optics on spacecraft degrade over time, leading to calibration drift. Lynx can be a cost effective platform for deploying a reference instrument to calibrate satellites with a frequent and fast turnaround and a successful return of the instrument. A calibrated reference instrument on Lynx can make collocated observations as another instrument and corrections are made for the latter, thus ensuring data consistency and mission longevity. Aboard a sRLV, atmospheric conditions that distort remotely sensed data (ground and spacecraft based) can be measured in situ. Moreover, an

  18. 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

  19. Plasmonic enhancement of ultraviolet fluorescence

    Science.gov (United States)

    Jiao, Xiaojin

    Plasmonics relates to the interaction between electromagnetic radiation and conduction electrons at metallic interfaces or in metallic nanostructures. Surface plasmons are collective electron oscillations at a metal surface, which can be manipulated by shape, texture and material composition. Plasmonic applications cover a broad spectrum from visible to near infrared, including biosensing, nanolithography, spectroscopy, optoelectronics, photovoltaics and so on. However, there remains a gap in this activity in the ultraviolet (UV, research. Motivating factors in the study of UV Plasmonics are the direct access to biomolecular resonances and native fluorescence, resonant Raman scattering interactions, and the potential for exerting control over photochemical reactions. This dissertation aims to fill in the gap of Plasmonics in the UV with efforts of design, fabrication and characterization of aluminium (Al) and magnesium (Mg) nanostructures for the application of label-free bimolecular detection via native UV fluorescence. The first contribution of this dissertation addresses the design of Al nanostructures in the context of UV fluorescence enhancement. A design method that combines analytical analysis with numerical simulation has been developed. Performance of three canonical plasmonic structures---the dipole antenna, bullseye nanoaperture and nanoaperture array---has been compared. The optimal geometrical parameters have been determined. A novel design of a compound bullseye structure has been proposed and numerically analyzed for the purpose of compensating for the large Stokes shift typical of UV fluorescence. Second, UV lifetime modification of diffusing molecules by Al nanoapertures has been experimentally demonstrated for the first time. Lifetime reductions of ~3.5x have been observed for the high quantum yield (QY) laser dye p-terphenyl in a 60 nm diameter aperture with 50 nm undercut. Furthermore, quantum-yield-dependence of lifetime reduction has been

  20. Monitoring and control of UV and UV-TiO2 disinfections for municipal wastewater reclamation using artificial neural networks

    International Nuclear Information System (INIS)

    Lin, Chuang-Hung; Yu, Ruey-Fang; Cheng, Wen-Po; Liu, Chun-Ru

    2012-01-01

    Highlights: ► ANN models can effectively control both UV and UV-TiO 2 disinfections for wastewater reuse. ► Comparing to UV disinfection, UV-TiO 2 disinfection can save 13.2–15.7% of UV dosage and capacity. ► SS decreases disinfection efficiency when UV doses were 2 . - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO 2 can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO 2 disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO 2 disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO 2 disinfections. A novel ANN control strategy is applied to control UV and UV-TiO 2 disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO 2 disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO 2 disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2–15.7%.

  1. Ultraviolet radiation for the sterilization of contact lenses

    International Nuclear Information System (INIS)

    Gritz, D.C.; Lee, T.Y.; McDonnell, P.J.; Shih, K.; Baron, N.

    1990-01-01

    Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study

  2. Hand protection from ultraviolet exposure

    International Nuclear Information System (INIS)

    Khazova, M.; O'Hagan, J.B.

    2006-01-01

    Full text of publication follows: A number of industrial applications and public services involve exposure to ultraviolet radiation (U.V.R.) from a variety of lamps and lasers, for example, in forensic examination, biological trans-illuminators, dentistry, laser material processing, microelectronics, etc. The proposed European Union Directive on Optical Radiation would place specific requirements on employers to provide adequate safety measures to reduce exposure to U.V.R., including gloves for hand protection. The selection of gloves should be based on a risk assessment and on the performance characteristics of the gloves for the task. However, current International and national standards do not describe evaluation procedures of disposable gloves for hand protection against non-ionising radiation. A methodology for assessment of the UV protection level for disposable gloves and a simple measurement protocol are proposed, based on a common approach with UV protection by clothing and sunscreens. Glove Ultraviolet Protection Factor is defined as a time-scale increase in exposure permitted for the hand protected by a glove with respect to an unprotected hand. However, the wide variety of U.V.R. sources and the real-life conditions of glove use (stretching and wetting the surface by liquids) bring substantial challenges to the assessment method. Our study of ∼ 50 samples of widely used disposable gloves made of different materials (nitrile, vinyl, latex and chloroprene) showed that for all tested gloves a change in U.V.R. attenuation with stretching is characteristic for the type of glove material and can be included as a scaling factor in the definition of U.V.R. protection. Glove material has a bigger effect on U.V.R. protection level than variations in the glove thickness or its colour. The following approaches are suggested to overcome the problem of variable U.V.R. sources: - Worst case scenario minimal protection level, most restrictive case - Application

  3. Hand protection from ultraviolet exposure

    Energy Technology Data Exchange (ETDEWEB)

    Khazova, M.; O' Hagan, J.B. [Health Protection Agency, Radiation Protection Division, Chilton, Did cot (United Kingdom)

    2006-07-01

    Full text of publication follows: A number of industrial applications and public services involve exposure to ultraviolet radiation (U.V.R.) from a variety of lamps and lasers, for example, in forensic examination, biological trans-illuminators, dentistry, laser material processing, microelectronics, etc. The proposed European Union Directive on Optical Radiation would place specific requirements on employers to provide adequate safety measures to reduce exposure to U.V.R., including gloves for hand protection. The selection of gloves should be based on a risk assessment and on the performance characteristics of the gloves for the task. However, current International and national standards do not describe evaluation procedures of disposable gloves for hand protection against non-ionising radiation. A methodology for assessment of the UV protection level for disposable gloves and a simple measurement protocol are proposed, based on a common approach with UV protection by clothing and sunscreens. Glove Ultraviolet Protection Factor is defined as a time-scale increase in exposure permitted for the hand protected by a glove with respect to an unprotected hand. However, the wide variety of U.V.R. sources and the real-life conditions of glove use (stretching and wetting the surface by liquids) bring substantial challenges to the assessment method. Our study of {approx} 50 samples of widely used disposable gloves made of different materials (nitrile, vinyl, latex and chloroprene) showed that for all tested gloves a change in U.V.R. attenuation with stretching is characteristic for the type of glove material and can be included as a scaling factor in the definition of U.V.R. protection. Glove material has a bigger effect on U.V.R. protection level than variations in the glove thickness or its colour. The following approaches are suggested to overcome the problem of variable U.V.R. sources: - Worst case scenario minimal protection level, most restrictive case - Application

  4. Improved UV-B screening capacity does not prevent negative effects of ambient UV irradiance on PSII performance in High Arctic plants. Results from a six year UV exclusion study

    DEFF Research Database (Denmark)

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

    2010-01-01

    Long-term responses of ambient solar ultraviolet (UV) radiation were investigated on Salix arctica and Vaccinium uliginosum in a High Arctic heath ecosystem in Zackenberg, northeast Greenland. Over a period of six years, UV exclusion was conducted in the growing season by means of filters: 60% UV......, exposing the vegetation to high spring UV-B, and to be present in the future to the degree the ozone layer is not fully recovered....

  5. Molecular analysis of the UV-inducible pili operon from Sulfolobus acidocaldarius

    NARCIS (Netherlands)

    Wolferen, Marleen van; Ajon, Małgorzata; Driessen, Arnold J.M.; Albers, Sonja-Verena

    2013-01-01

    Upon ultraviolet (UV) stress, hyperthermophilic Sulfolobus species show a highly induced transcription of a gene cluster responsible for pili biogenesis: the UV-inducible pili operon (ups operon). This operon is involved in UV-induced pili assembly, cellular aggregation, and subsequent DNA exchange

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

    Science.gov (United States)

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

    2015-01-01

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

  7. Effectiveness of a commonly-used technique for experimentally reducing plumage UV reflectance

    NARCIS (Netherlands)

    Korsten, P.; Limbourg, T.; Lessells, C.M.; Komdeur, J.

    2007-01-01

    Ultraviolet (UV) plumage is thought to be sexually selected through intra-sexual competition, female choice and differential allocation. Experimental manipulations of plumage UV reflectance are essential to demonstrate that mate choice or intra-sexual competition are causally related to UV

  8. Effectiveness of a commonly-used technique for experimentally reducing plumage UV reflectance

    NARCIS (Netherlands)

    Korsten, Peter; Limbourg, Tobias; Lessells, Catherine M.; Komdeur, Jan

    Ultraviolet (UV) plumage is thought to be sexually selected through intra-sexual competition, female choice and differential allocation. Experimental manipulations of plumage UV reflectance are essential to demonstrate that mate choice or intra-sexual competition are causally related to UV

  9. Beneficial and Detrimental Effects of UV on Aquatic Organisms: Implications of Spectral Variation

    NARCIS (Netherlands)

    Williamson, C.E.; Neale, P.J.; Grad, G.; Lange, de H.J.; Hargreaves, B.R.

    2001-01-01

    Solar ultraviolet radiation (UVR) may have beneficial as well as detrimental effects on living systems. For example, UV-B radiation (280¿320 nm) is generally damaging, while UV-A radiation (320¿400 nm) may cause damage or stimulate beneficial photorepair of UV-B damage. The nature of both direct and

  10. Nanostructure lipid carriers: A modish contrivance to overcome the ultraviolet effects

    Directory of Open Access Journals (Sweden)

    Priyanka Jain

    2017-06-01

    Full Text Available Protection of the skin from the ultraviolet radiation is the prime concern of society. An increase in the adverse effects by ultraviolet (UV radiation on the skin promoted cosmetic formulators to work in the area of UV blockers and their effective means of delivery. Nanostructured lipid carriers (NLCs is a modern and successful lipid carrier system in the cosmetic world associated with various advantages i.e., stability, effective drug loading capacity etc. NLCs also permits to load 70% of UV blockers which are sufficient to obtain recommended Sun Protection Factor (SPF which makes them suitable delivery systems for topical application of the UV blockers.

  11. Effects of solar ultraviolet radiation on tropical algal communities

    International Nuclear Information System (INIS)

    Santas, R.

    1989-01-01

    This study assessed some of the effects of solar ultraviolet (UV) radiation ion coral reef algal assemblages. The first part of the investigation was carried out under controlled laboratory conditions in the coral reef microcosm at the National Museum of Natural History in Washington, D.C., while a field counterpart was completed at the Smithsonian Institution's marine station on Grand Turk, Turks and Caicos Islands, in the eastern Caribbean. The study attempted to separate the effects of UV-A from those of UV-B. In the laboratory, algal turf assemblages exposed to simulated solar UV radiation produced 55.1% less biomass than assemblages that were not exposed to UV. Assemblages not exposed to UV were dominated by Ectocarpus rhodochondroides, whereas in the assemblage developing under high UV radiation, Enteromorpha prolifera and eventually Schizothrix calcicola dominated. Lower UV-B irradiances caused a proportional reduction in biomass production and had less pronounced effects on species composition. UV-A did not have any significant effects on either algal turf productivity or community structure. In the field, assemblages exposed to naturally occurring solar UV supported a biomass 40% lower than that of assemblages protected from UV-B exposure. Once again, UV-A did not inhibit algal turf productivity

  12. Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar

    Science.gov (United States)

    Whiteman, David N.; Rush, Kurt; Rabenhorst, Scott; Welch, Wayne; Cadirola, Martin; McIntire, Gerry; Russo, Felicita; Adam, Mariana; Venable, Demetrius; Connell, Rasheen; hide

    2010-01-01

    A high-performance Raman lidar operating in the UV portion of the spectrum has been used to acquire, for the first time using a single lidar, simultaneous airborne profiles of the water vapor mixing ratio, aerosol backscatter, aerosol extinction, aerosol depolarization and research mode measurements of cloud liquid water, cloud droplet radius, and number density. The Raman Airborne Spectroscopic Lidar (RASL) system was installed in a Beechcraft King Air B200 aircraft and was flown over the mid-Atlantic United States during July August 2007 at altitudes ranging between 5 and 8 km. During these flights, despite suboptimal laser performance and subaperture use of the telescope, all RASL measurement expectations were met, except that of aerosol extinction. Following the Water Vapor Validation Experiment Satellite/Sondes (WAVES_2007) field campaign in the summer of 2007, RASL was installed in a mobile trailer for groundbased use during the Measurements of Humidity and Validation Experiment (MOHAVE-II) field campaign held during October 2007 at the Jet Propulsion Laboratory s Table Mountain Facility in southern California. This ground-based configuration of the lidar hardware is called Atmospheric Lidar for Validation, Interagency Collaboration and Education (ALVICE). During theMOHAVE-II field campaign, during which only nighttime measurements were made, ALVICE demonstrated significant sensitivity to lower-stratospheric water vapor. Numerical simulation and comparisons with a cryogenic frost-point hygrometer are used to demonstrate that a system with the performance characteristics of RASL ALVICE should indeed be able to quantify water vapor well into the lower stratosphere with extended averaging from an elevated location like Table Mountain. The same design considerations that optimize Raman lidar for airborne use on a small research aircraft are, therefore, shown to yield significant dividends in the quantification of lower-stratospheric water vapor. The MOHAVE

  13. Ultraviolet radiation therapy and UVR dose models

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, David Robert, E-mail: davidrobert.grimes@oncology.ox.ac.uk [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland and Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom)

    2015-01-15

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed.

  14. Ultraviolet radiation therapy and UVR dose models

    International Nuclear Information System (INIS)

    Grimes, David Robert

    2015-01-01

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed

  15. 375-nm ultraviolet-laser based non-line-of-sight underwater optical communication

    KAUST Repository

    Sun, Xiaobin; Cai, Wenqi; Alkhazragi, Omar; Ooi, Ee-Ning; He, Hongsen; Chaaban, Anas; Shen, Chao; Oubei, Hassan M.; Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Alouini, Mohamed-Slim; Ooi, Boon S.

    2018-01-01

    For circumventing the alignment requirement of line-of-sight (LOS) underwater wireless optical communication (UWOC), we demonstrated a non-line-of-sight (NLOS) UWOC link adequately enhanced using ultraviolet (UV) 375-nm laser. Path loss was chosen

  16. Spectral Analysis of the Background in Ground-based, Long-slit ...

    Indian Academy of Sciences (India)

    1996-12-08

    Dec 8, 1996 ... Spectral Analysis of the Background in Ground-based,. Long-slit .... Figure 1 plots spectra from the 2-D array, after instrumental calibration and before correction for ..... which would merit attention and a better understanding.

  17. Ground-Based Global Navigation Satellite System Combined Broadcast Ephemeris Data (daily files) from NASA CDDIS

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset consists of ground-based Global Navigation Satellite System (GNSS) Combined Broadcast Ephemeris Data (daily files of all distinct navigation messages...

  18. Chasing Small Exoplanets with Ground-Based Near-Infrared Transit Photometry

    Science.gov (United States)

    Colon, K. D.; Barentsen, G.; Vinicius, Z.; Vanderburg, A.; Coughlin, J.; Thompson, S.; Mullally, F.; Barclay, T.; Quintana, E.

    2017-11-01

    I will present results from a ground-based survey to measure the infrared radius and other properties of small K2 exoplanets and candidates. The survey is preparation for upcoming discoveries from TESS and characterization with JWST.

  19. Zinc Selenide-Based Schottky Barrier Detectors for Ultraviolet-A and Ultraviolet-B Detection

    Directory of Open Access Journals (Sweden)

    V. Naval

    2010-01-01

    Full Text Available Wide-bandgap semiconductors such as zinc selenide (ZnSe have become popular for ultraviolet (UV photodetectors due to their broad UV spectral response. Schottky barrier detectors made of ZnSe in particular have been shown to have both low dark current and high responsivity. This paper presents the results of electrical and optical characterization of UV sensors based on ZnSe/Ni Schottky diodes fabricated using single-crystal ZnSe substrate with integrated UV-A (320–400 nm and UV-B (280–320 nm filters. For comparison, characteristics characterization of an unfiltered detector is also included. The measured photoresponse showed good discrimination between the two spectral bands. The measured responsivities of the UV-A and UV-B detectors were 50 mA/W and 10 mA/W, respectively. A detector without a UV filter showed a maximum responsivity of about 110 mA/W at 375 nm wavelength. The speed of the unfiltered detector was found to be about 300 kHz primarily limited by the RC time constant determined largely by the detector area.

  20. Establishing a ultraviolet radiation observational network and enhancing the study on ultraviolet radiation

    Science.gov (United States)

    Bai, Jianhui; Wang, Gengchen

    2003-09-01

    On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method for ultraviolet radiation (UV) in clear sky is obtained. The results show that the calculated values agree well with the observed, with maximum relative bias of 6.2% and mean relative bias for 24 months of 1.9%. Good results are also obtained when this method is applied in Guangzhou and Mohe districts. The long-term variation of UV radiation in clear sky over the Beijing area from 1979 to 1998 is calculated, and the UV variation trends and causes are discussed: direct and indirect UV energy absorption by increasing pollutants in the troposphere may have caused the UV decrease in clear sky in the last 20 years. With the enhancement of people’s quality of life and awareness of health, it will be valuable and practical to provid UV forecasts for typical cities and rural areas. So, we should develop and enhance UV study in systematic monitoring, forecasting, and developing a good and feasible method for UV radiation reporting in China, especially for big cities.

  1. A study on UV irradiated HDPE

    International Nuclear Information System (INIS)

    Sang Haibo; Liu Zimin; Wu Shishan; Shen Jian

    2006-01-01

    The structure and properties of HDPE irradiated by ultraviolet (UV) in ozone atmosphere were studied by FT-IR, XPS, gel, and water contact angle test. The oxygen-containing groups such as C=O, C-O and C(=O)O were introduced onto high density polyethylene (HDPE) chains through ultraviolet irradiation in ozone atmosphere, their content increased with the UV irradiation time. Under the same UV irradiation conditions, amount of the oxygen-containing groups introduced in ozone atmosphere was more than that in air atmosphere, indicating that the speed of oxygen-containing groups introduced through UV irradiation in ozone atmosphere was faster than that in air. Therefore, HDPE could be quickly functionalized through UV irradiation in ozone atmosphere. There was no gel formed in the HDPE irradiated in ozone atmosphere. After UV irradiation, the water contact angle of HDPE decreased, and its hydrophilicity was improved, suggesting that the compatibility between the irradiated HDPE and polar polymer or inorganic fillers may be better. Compared with HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The structure and properties of irradiated HDPE/CaCO 3 blend were also investigated. The results showed that the compatibility and interfacial action of the irradiated HDPE/CaCO 3 blend were improved compared to that of HDPE/CaCO 3 blend. The mechanical properties of irradiated HDPE/CaCO 3 blend increased with increasing irradiation time. (authors)

  2. Ultraviolet Spectroscopy of Asteroid(4) Vesta

    Science.gov (United States)

    Li, Jian-Yang; Bodewits, Dennis; Feaga, Lori M.; Landsman, Wayne; A'Hearn, Michael F.; Mutchler, Max J.; Russell, Christopher T.; McFadden, Lucy A.; Raymond, Carol A.

    2011-01-01

    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm arc derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope in the ultraviolet displays a sharp minimum ncar sub-Earth longitude of 20deg, and maximum in the eastern hemisphere. This is completely consistent with the distribution of the spectral slope in the visible wavelength. The uncertainty of the measurement in the ultraviolet is approx.20%, and in the visible wavelengths better than 10%. The amplitude of Vesta's rotational lightcurves is approx.10% throughout the range of wavelengths we observed, but is smaller at 950 nm (approx.6%) ncar the 1-micron mafic band center. Contrary to earlier reports, we found no evidence for any difference between the phasing of the ultraviolet and visible/ncar-infrared lightcurves with respect to sub-Earth longitude. Vesta's average spectrum between 220 and 950 nm can well be described by measured reflectance spectra of fine particle howardite-like materials of basaltic achondrite meteorites. Combining this with the in-phase behavior of the ultraviolet, visible. and ncar-infrared lightcurves, and the spectral slopes with respect to the rotational phase, we conclude that there is no global ultraviolet/visible reversal on Vesta. Consequently, this implies lack of global space weathering on Vesta. Keyword,: Asteroid Vesta; Spectrophotometry; Spectroscopy; Ultraviolet observations; Hubble Space Telescope observations

  3. Rapid modulation of ultraviolet shielding in plants is influenced by solar ultraviolet radiation and linked to alterations in flavonoids.

    Science.gov (United States)

    Barnes, Paul W; Tobler, Mark A; Keefover-Ring, Ken; Flint, Stephan D; Barkley, Anne E; Ryel, Ronald J; Lindroth, Richard L

    2016-01-01

    The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) and the resultant decrease in epidermal UV transmittance (TUV ) are primary protective mechanisms employed by plants against potentially damaging solar UV radiation and are critical components of the overall acclimation response of plants to changing solar UV environments. Whether plants can adjust this UV sunscreen protection in response to rapid changes in UV, as occurs on a diurnal basis, is largely unexplored. Here, we use a combination of approaches to demonstrate that plants can modulate their UV-screening properties within minutes to hours, and these changes are driven, in part, by UV radiation. For the cultivated species Abelmoschus esculentus, large (30-50%) and reversible changes in TUV occurred on a diurnal basis, and these adjustments were associated with changes in the concentrations of whole-leaf UV-absorbing compounds and several quercetin glycosides. Similar results were found for two other species (Vicia faba and Solanum lycopersicum), but no such changes were detected in Zea mays. These findings reveal a much more dynamic UV-protection mechanism than previously recognized, raise important questions concerning the costs and benefits of UV-protection strategies in plants and have practical implications for employing UV to enhance crop vigor and quality in controlled environments. © 2015 John Wiley & Sons Ltd.

  4. Effects of Ultraviolet Radiation on Human Health (invited paper)

    International Nuclear Information System (INIS)

    MacKie, R.M.

    2000-01-01

    The detrimental and beneficial effects of exposure to ultraviolet radiation in the UVB and UVA ranges are discussed. The main benefit of UV radiation is promoting the synthesis of vitamin D from precursors in the skin. Detrimental effects include acute sun damage in the form of sunburn and chronic sun damage leading to photoageing and possibly to cutaneous malignancies. Other detrimental effects of UV exposure include photosensitivity reactions to ingested drugs and rare examples of genetically determined photosensitivies. (author)

  5. Effects of Ultraviolet Radiation on Human Health (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    MacKie, R.M

    2000-07-01

    The detrimental and beneficial effects of exposure to ultraviolet radiation in the UVB and UVA ranges are discussed. The main benefit of UV radiation is promoting the synthesis of vitamin D from precursors in the skin. Detrimental effects include acute sun damage in the form of sunburn and chronic sun damage leading to photoageing and possibly to cutaneous malignancies. Other detrimental effects of UV exposure include photosensitivity reactions to ingested drugs and rare examples of genetically determined photosensitivies. (author)

  6. Thermoluminescent phosphors for ultraviolet radiation dosimetry - a review

    International Nuclear Information System (INIS)

    Nagpal, J.S.

    2001-01-01

    Intrinsic TL response of CaSO 4 , CaF 2 , Al 2 O 3 (Si,Ti), Mg 2 SiO 4 : Tb and lamp phosphors to ultraviolet radiation is reviewed. Taking into consideration the characteristics such as afterglow at RT, rate/flux dependence, linearity of response, useful range, spectral dependence and effect of sequential/tandem UV exposures CaF 2 :Eu 2+ is an ideal TL dosemeter for UV radiation dosimetry. (author)

  7. Stratospheric NO2 vertical profile retrieved from ground-based Zenith-Sky DOAS observations at Kiruna, Sweden

    Science.gov (United States)

    Gu, Myojeong; Enell, Carl-Fredrik; Hendrick, François; Pukite, Janis; Van Roozendael, Michel; Platt, Ulrich; Raffalski, Uwe; Wagner, Thomas

    2014-05-01

    Stratospheric NO2 destroys ozone and acts as a buffer against halogen-catalyzed ozone loss through the formation of reservoir species (ClONO2, BrONO2). Since the importance of both mechanisms depends on the altitude, the investigation of stratospheric NO2 vertical distribution can provide more insight into the role of nitrogen compounds in the destruction of ozone. Here we present stratospheric NO2 vertical profiles retrieved from twilight ground-based zenith-sky DOAS observations at Kiruna, Sweden (68.84°N, 20.41°E) covering 1997 - 2013 periods. This instrument observes zenith scattered sunlight. The sensitivity for stratospheric trace gases is highest during twilight due to the maximum altitude of the scattering profile and the light path through the stratosphere, which vary with the solar zenith angle. The profiling algorithm, based on the Optimal Estimation Method, has been developed by IASB-BIRA and successfully applied at other stations (Hendrick et al., 2004). The basic principle behind this profiling approach is that during twilight, the mean Rayleigh scattering altitude scans the stratosphere rapidly, providing height-resolved information on the absorption by stratospheric NO2. In this study, the long-term evolution of the stratospheric NO2 profile at polar latitude will be investigated. Hendrick, F., B. Barret, M. Van Roozendael, H. Boesch, A. Butz, M. De Mazière, F. Goutail, C. Hermans, J.-C. Lambert, K. Pfeilsticker, and J.-P. Pommereau, Retrieval of nitrogen dioxide stratospheric profiles from ground-based zenith-sky UV-visible observations: Validation of the technique through correlative comparisons, Atmospheric Chemistry and Physics, 4, 2091-2106, 2004

  8. Ultraviolet Spectrophotometry of VV Cephei

    Directory of Open Access Journals (Sweden)

    Young Woon Kang

    1992-06-01

    Full Text Available The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 3250 Å, 2550 Å and 2850 Å have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atomsphere of the M star.

  9. Ultraviolet signals in birds are special.

    Science.gov (United States)

    Hausmann, Franziska; Arnold, Kathryn E; Marshall, N Justin; Owens, Ian P F

    2003-01-07

    Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a significant positive association between UV reflectance and courtship displays. Among parrots (Psittaciformes), 68% of surveyed species have fluorescent plumage, and again there is a strong positive association between courtship displays and fluorescence. These associations are not artefacts of the plumage used in courtship displays, being generally more 'colourful' because there is no association between display and colours lacking UV reflectance or fluorescence. Equally, these associations are not phylogenetic artefacts because all results remain unchanged when families or genera, rather than species, are used as independent data points. We also find that, in parrots, fluorescent plumage is usually found adjacent to UV-reflective plumage. Using a simple visual model to examine one parrot, the budgerigar Melopsittacus undulatus, we show that the juxtaposition of UV-reflective and fluorescent plumage leads to a 25-fold increase in chromatic contrast to the budgerigar's visual system. Taken together, these results suggest that signals based on UV contrast are of special importance in the context of active sexual displays. We review briefly six hypotheses on why this may be the case: suitability for short-range signalling; high contrast with backgrounds; invisibility to predators; exploitation of pre-existing sensory biases; advertisement of feather structure; and amplification of behavioural signals.

  10. Interdependence between body surface area and ultraviolet B dose in vitamin D production

    DEFF Research Database (Denmark)

    Bogh, M K B; Schmedes, Anne; Philipsen, P A

    2011-01-01

    Ultraviolet (UV) B radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) [25(OH)D], but the relationship to body surface area and UVB dose needs investigation.......Ultraviolet (UV) B radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) [25(OH)D], but the relationship to body surface area and UVB dose needs investigation....

  11. 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...

  12. Numerical and experimental investigation of UV disinfection for water treatment

    International Nuclear Information System (INIS)

    Li, H.Y.; Osman, H.; Kang, C.W.; Ba, T.

    2017-01-01

    Highlights: • UV irradiation for water treatment is numerically and experimentally investigated. • Fluence rate E increases exponentially with the increase of UVT. • UV dose distribution moves to a high range with increase of UVT and lamp power. • A linear relationship is observed between fluence rate E and average UV dose D_a_v_e. • D_a_v_e decreases with the increase of UVT and fluid flow rate. - Abstract: Disinfection by ultraviolet (UV) for water treatment in a UV reactor is numerically and experimentally investigated in this paper. The flow of water, UV radiation transportation as well as microorganism particle trajectories in the UV reactor is simulated. The effects of different parameters including UV transmittance (UVT), lamp power and water flow rate on the UV dose distribution and average UV dose are studied. The UV reactor performance in terms of average UV dose under these parameters is analysed. Comparisons are made between experiments and simulations on the average UV dose and reasonable agreement is achieved. The results show that the fluence rate increases exponentially with the increase of UVT. The UV dose distribution profiles moves to a high range of UV dose with the increase of UVT and lamp power. The increase of water flow rate reduces the average exposure time of microorganism particles to the UV light, resulting in the shifting of UV dose distribution to a low range of UV dose. A linear relationship is observed between fluence rate and the average UV dose. The average UV dose increases with the increase of lamp power while it decreases with the increase of UVT and water flow rate.

  13. Long-term visual health risks from solar ultraviolet radiation

    International Nuclear Information System (INIS)

    Waxler, M.

    1987-01-01

    Ocular exposure to the ultraviolet radiation (UV) contained in sunlight may result in long-term visual health problems. UV plays a role in the etiology of cataracts and possibly in the etiology of visual impairments associated with solar retinopathy, retinopathy of prematurity, ocular aging, cystoid macular edema, retinitis pigmentosa, and senile macular degeneration. The exact does relationships between known UV bioeffects and these ocular problems is, however, uncertain. Thus, there are questions about the extent to which protective measures should be taken to reduce UV exposure of the eye. This paper identifies the long-term visual health problems potentially associated with ocular exposure to solar UV; proposes worst-case assumptions for the role of solar UV in these visual problems; and recommends protective measures based on damage thresholds and worst-case assumptions

  14. Effects of ultraviolet irradiation on skin of guinea pig

    International Nuclear Information System (INIS)

    Zhang Wenwen; Chen Qiang; Li Peng; Ling Ling; Lin Xiaochen; Ren Shuping; Liu Yajuan; Li Yun

    2008-01-01

    Objective: To explore the adverse effects of ultraviolet B (UV-B) on the skin of guinea pig. Methods: Guinea pig skin was irradiated with UV-B, the skin changes in external appearance, pathology, and the contents of OH and O 2 - produced in the skin were determined to study the adverse effects of UV-B on the guinea pig skin. Results: UV-B caused red swelling and desquamation of skin, with the increasing of the UV-B irradiation, the cells in stratum spinosum began to proliferate vigorously, the MDA and ROS contents in UVB radiation group were significantly higher than those in control group (P<0.05). Conclusion: UV-B can cause injury to guinea pig skin and has the potential to produce skin cancer. (authors)

  15. UNLAMINATED GAFCHROMIC EBT3 FILM FOR ULTRAVIOLET RADIATION MONITORING.

    Science.gov (United States)

    Welch, David; Randers-Pehrson, Gerhard; Spotnitz, Henry M; Brenner, David J

    2017-11-01

    Measurement of ultraviolet (UV) radiation is important for human health, especially with the expanded usage of short wavelength UV for sterilization purposes. This work examines unlaminated Gafchromic EBT3 film for UV radiation monitoring. The authors exposed the film to select wavelengths in the UV spectrum, ranging from 207 to 328 nm, and measured the change in optical density. The response of the film is wavelength dependent, and of the wavelengths tested, the film was most sensitive to 254 nm light, with measurable values as low as 10 µJ/cm2. The film shows a dose-dependent response that extends over more than four orders of magnitude. The response of the film to short wavelength UV is comparable to the daily safe exposure limits for humans, thus making it valuable as a tool for passive UV radiation monitoring. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Ultraviolet light-induced suppression of antigen presentation

    International Nuclear Information System (INIS)

    Spellman, C.W.; Tomasi, T.B.

    1983-01-01

    Ultraviolet (UV) light irradiation of animals results in the development of specific T suppressor cells that inhibit antitumor immune responses. It is thought that suppression may arise as a consequence of altered antigen presentation by UV-irradiated epidermal cells. This hypothesis is based on evidence demonstrating that specific lymphoid tissues from UV-irradiated hosts exhibit impaired antigen-presenting function and that animals cannot be contact sensitized when antigens are applied to a UV-irradiated skin site. Langerhans cells of the skin are likely candidates as targets of UV-induced defects in antigen presentation as they bear Fc and C3b receptors, express Ia antigens, are of bone marrow origin, and are capable of presenting antigen in vitro. We speculate on the possible clinical usefulness of UV-induced tolerance to specific antigens such as those encountered in monoclonal antibody therapy and tissue transplantation

  17. EGFR Activation and Ultraviolet Light‐Induced Skin Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Taghrid B. El-Abaseri

    2007-01-01

    Full Text Available The epidermal growth factor receptor (EGFR regulates the proliferation of keratinocytes through multiple mechanisms that differ depending on the localization of the cell within the skin. Ultraviolet (UV irradiation, the main etiologic factor in the development of skin cancer, also activates the receptor. In this review, we discuss how the UV-induced activation of EGFR regulates the response of the skin to UV. UV-induced EGFR activation increases keratinocyte proliferation, suppresses apoptosis, and augments and accelerates epidermal hyperplasia in response to UV. Pharmacological inhibition of the UV-induced activation of EGFR in a genetically initiated mouse skin tumorigenesis model suppresses tumorigenesis and the activation of mitogen-activated protein (MAP kinases and phosphatidyl inositol-3-kinase (PI3K/AKT signaling pathways. EGFR has pleiotropic, complex, and cell-type-specific functions in cutaneous keratinocytes; suggesting that the receptor is an appropriate target for the development of molecularly targeted therapies for skin cancer and other pathologies.

  18. Ultraviolet vision may be widespread in bats

    Science.gov (United States)

    Gorresen, P. Marcos; Cryan, Paul; Dalton, David C.; Wolf, Sandy; Bonaccorso, Frank

    2015-01-01

    Insectivorous bats are well known for their abilities to find and pursue flying insect prey at close range using echolocation, but they also rely heavily on vision. For example, at night bats use vision to orient across landscapes, avoid large obstacles, and locate roosts. Although lacking sharp visual acuity, the eyes of bats evolved to function at very low levels of illumination. Recent evidence based on genetics, immunohistochemistry, and laboratory behavioral trials indicated that many bats can see ultraviolet light (UV), at least at illumination levels similar to or brighter than those before twilight. Despite this growing evidence for potentially widespread UV vision in bats, the prevalence of UV vision among bats remains unknown and has not been studied outside of the laboratory. We used a Y-maze to test whether wild-caught bats could see reflected UV light and whether such UV vision functions at the dim lighting conditions typically experienced by night-flying bats. Seven insectivorous species of bats, representing five genera and three families, showed a statistically significant ‘escape-toward-the-light’ behavior when placed in the Y-maze. Our results provide compelling evidence of widespread dim-light UV vision in bats.

  19. Control of zebra mussels with ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D.P.

    1998-07-01

    This paper presents the results of research on the effects of low and medium pressure ultraviolet (UV) radiation on zebra mussel mortality carried out between 1992 and 1995. An initial 1992 study, carried out by Aquatic Sciences (ASI), showed that flow-through UV systems have the ability to kill zebra mussels and prevent them from attaching to downstream surfaces. However, this work did not include expanded testing to determine the limitations of UV radiation at higher flow rates or to further define effective working parameters. The 1994 study was carried out at the Lennox Thermal Generating Station (TGS) of Ontario Hydro in Kingston, Ontario. This study involved the testing of two open channel UV systems (medium and low pressure) in an effort to determine flow rates and volumes for which UV disinfection would be effective and practical for the prevention of zebra mussel infestation. It was recommended that medium pressure (MP) and low pressure (LP) UV systems be tested for their ability to control downstream settlement of zebra mussels, in flow-through trials.

  20. Enhancement of photosynthesis in Sorghum bicolor by ultraviolet radiation

    International Nuclear Information System (INIS)

    Johnson, G.A.; Day, T.A.

    2002-01-01

    We assessed the influence of ultraviolet radiation (UV) on net photosynthetic CO 2 assimilation rate (Pn) in Sorghum bicolor, with particular attention to examining whether UV can enhance Pn via direct absorption of UV and absorption of UV-induced blue fluorescence by photosynthetic pigments. A polychromatic UV response spectrum of leaves was constructed by measuring Pn under different UV supplements using filters that had sharp transmission cut-offs from 280 to 382 nm, against a background of non-saturating visible light. When the abaxial surface was irradiated, P n averaged 4.6% higher with the UV supplement that cut-off UV at 311 nm, compared to lower and higher UV wavelength supplements. This former supplement differed from higher wavelength supplements by primarily providing more UV between 320 and 350 nm. To assess the possibility of direct absorption of UV by photosynthetic pigments, we measured the absorbance of extracted chlorophylls. Chlorophyll a had absorbance peaks at 340 and 389 nm that were 49 and 72% of that at the sorét peak. Chlorophyll b had absorbance peaks at 315 and 346 nm that were both 35% of that at the sorét peak. Since the epidermis transmits some UV, the strong UV absorbance of chlorophyll implies a potential role for irradiance beyond the bounds of the conventionally defined photosynthetically active radiation waveband (400–700 nm). To assess the role of absorption of UV-induced blue fluorescence, we measured the UV-induced fluorescence excitation and emission spectra of leaves. Abaxial excitation peaked at 328 nm, while emission peaked at 446 nm. In this analysis, we used our abaxial fluorescence excitation spectrum and the UV photosynthetic inhibition spectrum of Caldwell et al. (1986) to weight the UV irradiance with each cut-off filter, thereby estimating the potential contribution of UV-induced blue fluorescence to photosynthesis and the inhibitory effects of UV irradiance on photosynthesis, respectively. With a non

  1. Simultaneous observation of auroral substorm onset in Polar satellite global images and ground-based all-sky images

    Science.gov (United States)

    Ieda, Akimasa; Kauristie, Kirsti; Nishimura, Yukitoshi; Miyashita, Yukinaga; Frey, Harald U.; Juusola, Liisa; Whiter, Daniel; Nosé, Masahito; Fillingim, Matthew O.; Honary, Farideh; Rogers, Neil C.; Miyoshi, Yoshizumi; Miura, Tsubasa; Kawashima, Takahiro; Machida, Shinobu

    2018-05-01

    Substorm onset has originally been defined as a longitudinally extended sudden auroral brightening (Akasofu initial brightening: AIB) followed a few minutes later by an auroral poleward expansion in ground-based all-sky images (ASIs). In contrast, such clearly marked two-stage development has not been evident in satellite-based global images (GIs). Instead, substorm onsets have been identified as localized sudden brightenings that expand immediately poleward. To resolve these differences, optical substorm onset signatures in GIs and ASIs are compared in this study for a substorm that occurred on December 7, 1999. For this substorm, the Polar satellite ultraviolet global imager was operated with a fixed-filter (170 nm) mode, enabling a higher time resolution (37 s) than usual to resolve the possible two-stage development. These data were compared with 20-s resolution green-line (557.7 nm) ASIs at Muonio in Finland. The ASIs revealed the AIB at 2124:50 UT and the subsequent poleward expansion at 2127:50 UT, whereas the GIs revealed only an onset brightening that started at 2127:49 UT. Thus, the onset in the GIs was delayed relative to the AIB and in fact agreed with the poleward expansion in the ASIs. The fact that the AIB was not evident in the GIs may be attributed to the limited spatial resolution of GIs for thin auroral arc brightenings. The implications of these results for the definition of substorm onset are discussed herein.[Figure not available: see fulltext.

  2. Evolution of solar ultraviolet luminosity

    International Nuclear Information System (INIS)

    Zahnle, K.J.; Walker, J.C.G.

    1982-01-01

    In view of the major role of the sun in defining the properties of planetary atmospheres, their evolution cannot be fully understood outside the context of an evolving sun. The ultraviolet radiation is especially interesting because of its strong interaction with planetary atmospheres. We use astronomical observation of stars that are analogous to the sun in order to reconstruct a tentative account of the evolution of solar UV luminosity. A wealth of evidence indicates that the young sun was a much more powerful source of energetic particles and radiation than it is today. While on the main sequence, solar activity has declined as an inverse power law of age (between t -5 and t/sup -1.2/) as a consequence of angular momentum loss to the solar wind. Recent IUE satellite observations of premain sequence stars suggest that before the sun reached the main sequence (at an age of about 50 m.y.), it may have emitted as much as 10 4 times as much ultraviolet radiation (γ<2000 A) than it does today. These results could impact our understanding of the photochemistry and escape of constituents of primordial planetary atmospheres

  3. Ultraviolet reflection enhances the risk of predation in a vertebrate

    Directory of Open Access Journals (Sweden)

    Ricarda MODARRESSIE, Ingolf P. RICK, Theo C. M. BAKKER

    2013-04-01

    Full Text Available Many animals are sensitive to ultraviolet light and also possess UV-reflective regions on their body surface. Individuals reflecting UV have been shown to be preferred during social interactions such as mate choice or shoaling decisions. However, whether those body UV-reflections enhance also the conspicuousness to UV-sensitive predators and therefore entail costs for its bearer is less well documented. Two size-matched three-spined sticklebacks Gasterosteus aculeatus, one enclosed in a UV-transmitting (UV+ and another in a UV-blocking (UV- chamber, were simultaneously presented to individual brown trout Salmo trutta. “yearlings”. Brown trout of this age are sensitive to the UV part of the electromagnetic spectrum and are natural predators of three-spined sticklebacks. The stickleback that was attacked first as well as the subsequent number of attacks was recorded. Sticklebacks enclosed in the UV-transmitting chamber were attacked first significantly more often compared to sticklebacks enclosed in the UV-blocking chamber. Control experiments using neutral density filters revealed that this was more likely due to UV having an influence on hue perception rather than brightness discrimination. The difference in attack probability corresponded to the difference in chromatic contrasts between sticklebacks and the experimental background calculated for both the UV+ and UV- conditions in a physiological model of trout colour vision. UV reflections seem to be costly by enhancing the risk of predation due to an increased conspicuousness of prey. This is the first study in a vertebrate, to our knowledge, demonstrating direct predation risk due to UV wavelengths [Current Zoology 59 (2: 151-159, 2013].

  4. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    International Nuclear Information System (INIS)

    Bero, M A; Abukassem, I

    2009-01-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  5. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    Science.gov (United States)

    Bero, M. A.; Abukassem, I.

    2009-05-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  6. Ultraviolet and X-ray variability of NGC 4051 over 45 days with XMM-Newton and Swift

    NARCIS (Netherlands)

    Alston, W.N.; Vaughan, S.; Uttley, P.

    2013-01-01

    We analyse 15 XMM-Newton observations of the Seyfert galaxy NGC 4051 obtained over 45 d to determine the ultraviolet (UV) light curve variability characteristics and search for correlated UV/X-ray emission. The UV light curve shows variability on all time-scales, however with lower fractional rms

  7. Ultraviolet radiation and the snow alga Chlamydomonas nivalis (Bauer) Wille.

    Science.gov (United States)

    Gorton, Holly L; Vogelmann, Thomas C

    2003-06-01

    Aplanospores of Chlamydomonas nivalis are frequently found in high-altitude, persistent snowfields where they are photosynthetically active despite cold temperatures and high levels of visible and ultraviolet (UV) radiation. The goals of this work were to characterize the UV environment of the cells in the snow and to investigate the existence and localization of screening compounds that might prevent UV damage. UV irradiance decreased precipitously in snow, with UV radiation of wavelengths 280-315 nm and UV radiation of wavelengths 315-400 nm dropping to 50% of incident levels in the top 1 and 2 cm, respectively. Isolated cell walls exhibited UV absorbance, possibly by sporopollenin, but this absorbance was weak in images of broken or plasmolyzed cells observed through a UV microscope. The cells also contained UV-absorbing cytoplasmic compounds, with the extrachloroplastic carotenoid astaxanthin providing most of the screening. Additional screening compound(s) soluble in aqueous methanol with an absorption maximum at 335 nm played a minor role. Thus, cells are protected against potentially high levels of UV radiation by the snow itself when they live several centimeters beneath the surface, and they rely on cellular screening compounds, chiefly astaxanthin, when located near the surface where UV fluxes are high.

  8. 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

  9. 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

  10. Ground-Based Remote Sensing and Imaging of Volcanic Gases and Quantitative Determination of Multi-Species Emission Fluxes

    Directory of Open Access Journals (Sweden)

    Ulrich Platt

    2018-01-01

    Full Text Available The physical and chemical structure and the spatial evolution of volcanic plumes are of great interest since they influence the Earth’s atmospheric composition and the climate. Equally important is the monitoring of the abundance and emission patterns of volcanic gases, which gives insight into processes in the Earth’s interior that are difficult to access otherwise. Here, we review spectroscopic approaches (from ultra-violet to thermal infra-red to determine multi-species emissions and to quantify gas fluxes. Particular attention is given to the emerging field of plume imaging and quantitative image interpretation. Here UV SO2 cameras paved the way but several other promising techniques are under study and development. We also give a brief summary of a series of initial applications of fast imaging techniques for volcanological research.

  11. Effect of UV irradiation on cutaneous cicatrices

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  12. The Ultraviolet Albedo of Ganymede

    Science.gov (United States)

    McGrath, Melissa; Hendrix, A.

    2013-10-01

    A large set of ultraviolet images of Ganymede have been acquired with the Hubble Space Telescope over the last 15 years. These images have been used almost exclusively to study Ganymede’s stunning auroral emissions (Feldman et al. 2000; Eviatar et al. 2001; McGrath et al. 2004; Saur et al. 2011; McGrath et al. 2013), and even the most basic information about Ganymede’s UV albedo has yet to be gleaned from these data. We will present a first-cut analysis of both disk-averaged and spatially-resolved UV albedos of Ganymede, with focus on the spatially-resolved Lyman-alpha albedo, which has never been considered previously for this satellite. Ganymede's visibly bright regions are known to be rich in water ice, while the visibly dark regions seem to be more carbonaceous (Carlson et al., 1996). At Lyman-alpha, these two species should also have very different albedo values. References Carlson, R. and 39 co-authors, Near-infrared spectroscopy and spectral mapping of Jupiter and the Galilean satellites: Results from Galileo’s initial orbit, Science, 274, 385-388, 1996. Eviatar, A., D. F. Strobel, B. C. Wolven, P. D. Feldman, M. A. McGrath, and D. J. Williams, Excitation of the Ganymede ultraviolet aurora, Astrophys. J, 555, 1013-1019, 2001. Feldman, P. D., M. A. McGrath, D. F. Strobel, H. W. Moos, K. D. Retherford, and B. C. Wolven, HST/STIS imaging of ultraviolet aurora on Ganymede, Astrophys. J, 535, 1085-1090, 2000. McGrath M. A., Lellouch E., Strobel D. F., Feldman P. D., Johnson R. E., Satellite Atmospheres, Chapter 19 in Jupiter: The Planet, Satellites and Magnetosphere, ed. F. Bagenal, T. Dowling, W. McKinnon, Cambridge University Press, 2004. McGrath M. A., Jia, Xianzhe; Retherford, Kurt; Feldman, Paul D.; Strobel, Darrell F.; Saur, Joachim, Aurora on Ganymede, J. Geophys. Res., doi: 10.1002/jgra.50122, 2013. Saur, J., S. Duling, S., L. Roth, P. D. Feldman, D. F. Strobel, K. D. Retherford, M. A. McGrath, A. Wennmacher, American Geophysical Union, Fall Meeting

  13. Remote Sensing of the Upper Atmosphere and the Ionosphere in the Extreme and Far Ultraviolet: Results from the LITES Experiment aboard the IS

    Science.gov (United States)

    Finn, S. C.; Chakrabarti, S.; Stephan, A. W.; Geddes, G.; Budzien, S. A.; Cook, T.; Aryal, S.; Martel, J.; Galkin, I. A.; Erickson, P. J.

    2017-12-01

    The Limb-Imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) was launched as part of the Space Test Program Houston #5 (STP-H5) payload aboard a commercial resupply flight on February 19, 2017 and was subsequently installed on the International Space Station (ISS). LITES is an imaging spectrograph that spans the 60 - 140 nm wavelength range at 1 nm spectral resolution and samples tangent altitudes 150 - 350 km with 0.2° angular resolution. LITES, in combination with the GPS Radio Occultation and Ultraviolet Photometry - Colocated (GROUP-C) experiment, which includes a GPS receiver and a nadir viewing 135.6 nm photometer, jointly collect new information on the thermosphere and the ionosphere using simultaneous UV and radio emissions. LITES, which uses standard stars to perform in-flight calibration, observes altitude profiles of day and night airglow emissions that are being used to infer thermospheric and ionospheric density profiles. Furthermore, due to the inclination of the ISS, LITES has also observed auroral spectrum and their altitude and spatial variations. Finally, geomagnetic storm effects on its UV emissions can be used to remotely sense their effects on the upper atmospheric morphology. These ISS observations,which are complement to the upcoming ICON and GOLD NASA missions, are focused on ionosphere-atmosphere coupling and global-scale atmospheric response to space weather observed from higher altitudes . We will present an overview of the LITES instrument, some early results from the first few months of operations. We will also summarize the advantages in calibration and validation activities that are possible through space-based LITES, GROUP-C and stellar measurements and simultaneous ground-based optical and radar observations.

  14. Dermal damage from ultraviolet radiation

    International Nuclear Information System (INIS)

    Kligman, L.H.

    1988-01-01

    Ultraviolet (UV) radiation is increasingly recognized as the cause of a vast number of changes in the skin of humans and animals. These include alterations at the molecular, cellular, tissue and systematic levels. In the recent past, much has been learned about the immediate effects in skin of acute UV exposure (i.e. sunburn) with its epidermal cell death, inflammation and vasolidation. With chronic exposure, many of the clinical and histologic effects can be seen only after decades. Visually, these are hyper- and hypopigmented macules, dry scaly, wrinkled skin with a variety of benign, pre-malignant and malignant neoplasms. All epidermal in origin, they lead, inexorably in humans, to the appearance the authors described as photo-aged. Underlying many of these visible manifestations are drastic changes in the dermis. These relate chiefly to destruction of mature collagen, with a compensatory overproduction of reticulin fibers, hyperplasia of elastic fibers eventuating in elastosis, increased levels of the glycosaminoglycans (GAGs) comprising the ground substance and changes in the microvasculature. First described in actinically damaged humans, systematic investigation required an animal model

  15. Ultraviolet A phototherapy for sclerotic skin diseases: a systematic review.

    NARCIS (Netherlands)

    Kroft, Ilse; Berkhof, N.J.; Kerkhof, P.C.M. van de; Gerritsen, R.; Jong, E.M.G.J. de

    2008-01-01

    BACKGROUND: Ultraviolet (UV) A-1 phototherapy is now available for a variety of skin diseases. Increasingly since 1995, there have been investigations of the efficacy of UVA-1 (340-400 nm) therapy for sclerotic skin diseases. Most studies undertaken treated patients who had localized scleroderma,

  16. Sensitivity of the vibrios to ultraviolet-radiation

    International Nuclear Information System (INIS)

    Banerjee, S.K.; Chatterjee, S.N.

    1977-01-01

    The ultraviolet-inactivation kinetics of a number of strains of Vibrio cholerae (classical), Vibrio cholerae (el tor), NAG vibrios and Vibrio parahaemolyticus were investigated. Statistical analyses revealed significant differences between any two of the four types of vibrio in respect of their sensitivity to U.V. (author)

  17. Photochemical reaction monitoring by ultra-violet spectrophotometry.

    Science.gov (United States)

    Roig, B; Touraud, E; Thomas, O

    2002-11-01

    Within the framework of the monitoring of the trichloroacetylchloride (TCAC) photosynthesis, ultra-violet (UV) spectrophotometry is proposed as a simple and rapid tool allowing, in real time, the control of the process efficiency. A good correlation has been obtained between the results acquired by this alternative method and the standard gas chromatography.

  18. Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

    Science.gov (United States)

    Yip, Cheng-Wai

    2007-01-01

    Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

  19. Highly efficient deep ultraviolet generation by sum-frequency mixing ...

    Indian Academy of Sciences (India)

    Ultraviolet laser radiation; walk-off compensation; third harmonic generation; nonlinear optical material. ... Because of its large birefringence, BBO crystal permits the generation of UV radiation near 200 nm by THG ... A, B and C are three different configurations for THG, A – Single crystal, B – two crystals (B2 and B3 in.

  20. Invisible Misconceptions: Student Understanding of Ultraviolet and Infrared Radiation

    Science.gov (United States)

    Libarkin, Julie C.; Asghar, Anila; Crockett, C.; Sadler, Philip

    2011-01-01

    The importance of nonvisible wavelengths for the study of astronomy suggests that student understanding of nonvisible light is an important consideration in astronomy classrooms. Questionnaires, interviews, and panel discussions were used to investigate 6-12 student and teacher conceptions of ultraviolet (UV) and infrared (IR). Alternative…

  1. UV SEDs of early-type cluster galaxies: a new look at the UV upturn

    Science.gov (United States)

    Ali, S. S.; Bremer, M. N.; Phillipps, S.; De Propris, R.

    2018-05-01

    Using GALEX, Ultraviolet Optical Telescope (UVOT), and optical photometry, we explore the prevalence and strength of the Ultraviolet (UV) upturn in the spectra of quiescent early-type galaxies in several nearby clusters. Even for galaxies with completely passive optical colours, there is a large spread in vacuum UV colour consistent with almost all having some UV upturn component. Combining GALEX and UVOT data below 3000 Å, we generate for the first time comparatively detailed UV spectral energy distributions for Coma cluster galaxies. Fitting the UV upturn component with a blackbody, 26 of these show a range of characteristic temperatures (10 000-21 000K) for the UV upturn population. Assuming a single temperature to explain GALEX-optical colours could underestimate the fraction of galaxies with UV upturns and mis-classify some as systems with residual star formation. The UV upturn phenomenon is not an exclusive feature found only in giant galaxies; we identify galaxies with similar (or even bluer) FUV - V colours to the giants with upturns over a range of fainter luminosities. The temperature and strength of the UV upturn are correlated with galaxy mass. Under the plausible hypothesis that the sources of the UV upturn are blue horizontal branch stars, the most likely mechanism for this is the presence of a substantial (between 4 per cent and 20 per cent) Helium-rich (Y > 0.3) population of stars in these galaxies, potentially formed at z ˜ 4 and certainly at z > 2; this plausibly sets a lower limit of {˜ } {0.3- 0.8} × 10^{10} M⊙ to the in situ stellar mass of ˜L* galaxies at this redshift.

  2. Ultraviolet-B radiation effects on leaf fluorescence characteristics in cultivars of soybean

    International Nuclear Information System (INIS)

    Miles, D.

    1993-01-01

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

  3. Ultra-violet emission in Ho:ZBLAN fiber

    International Nuclear Information System (INIS)

    Kowalska, M.; Klocek, G.; Piramidowicz, R.; Malinowski, M.

    2004-01-01

    We report on the short wavelength (green, blue, and ultra-violet (UV)) emission in trivalent holmium doped fluoro-zirconate fiber (Ho 3+ :ZBLAN) under direct and upconversion pumping. Efficient red to UV upconversion has been observed using 647 nm cw pumping by krypton ion laser. A close to cubic UV signal intensity dependence on incident red pump power was determined, confirming the three-photon character of the observed process. The responsible upconversion mechanisms were investigated and shown to be excited state absorption (ESA) via low-lying 5 I 7 and 5 I 6 sates. Dynamics of the involved excited states have been studied under pulsed laser excitation

  4. Ultraviolet Radiation Dose National Standard of México

    Science.gov (United States)

    Cardoso, R.; Rosas, E.

    2006-09-01

    We present the Ultraviolet (UV) Radiation Dose National Standard for México. The establishment of this measurement reference at Centro Nacional de Metrología (CENAM) eliminates the need of contacting foreign suppliers in the search for traceability towards the SI units when calibrating instruments at 365 nm. Further more, the UV Radiation Dose National Standard constitutes a highly accurate and reliable source for the UV radiation dose measurements performed in medical and cosmetic treatments as in the the food and pharmaceutics disinfection processes, among other.

  5. UV spectrophotometry of the Metronidazole

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-10-01

    Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

  6. International Ultraviolet Explorer satellite observations of seven high-excitation planetary nebulae.

    Science.gov (United States)

    Aller, L H; Keyes, C D

    1980-03-01

    Observations of seven high-excitation planetary nebulae secured with the International Ultraviolet Explorer (IUE) satellite were combined with extensive ground-based data to obtain electron densities, gas kinetic temperatures, and ionic concentrations. We then employed a network of theoretical model nebulae to estimate the factors by which observed ionic concentrations must be multiplied to obtain elemental abundances. Comparison with a large sample of nebulae for which extensive ground-based observations have been obtained shows nitrogen to be markedly enhanced in some of these objects. Possibly most, if not all, high-excitation nebulae evolve from stars that have higher masses than progenitors of nebulae of low-to-moderate excitation.

  7. Hybrid 2D patterning using UV laser direct writing and aerosol jet printing of UV curable polydimethylsiloxane

    Science.gov (United States)

    Obata, Kotaro; Schonewille, Adam; Slobin, Shayna; Hohnholz, Arndt; Unger, Claudia; Koch, Jürgen; Suttmann, Oliver; Overmeyer, Ludger

    2017-09-01

    The hybrid technique of aerosol jet printing and ultraviolet (UV) laser direct writing was developed for 2D patterning of thin film UV curable polydimethylsiloxane (PDMS). A dual atomizer module in an aerosol jet printing system generated aerosol jet streams from material components of the UV curable PDMS individually and enables the mixing in a controlled ratio. Precise control of the aerosol jet printing achieved the layer thickness of UV curable PDMS as thin as 1.6 μm. This aerosol jet printing system is advantageous because of its ability to print uniform thin-film coatings of UV curable PDMS on planar surfaces as well as free-form surfaces without the use of solvents. In addition, the hybrid 2D patterning using the combination of UV laser direct writing and aerosol jet printing achieved selective photo-initiated polymerization of the UV curable PDMS layer with an X-Y resolution of 17.5 μm.

  8. Experimental evaluation of optimization method for developing ultraviolet barrier coatings

    Science.gov (United States)

    Gonome, Hiroki; Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-01-01

    Ultraviolet (UV) barrier coatings can be used to protect many industrial products from UV attack. This study introduces a method of optimizing UV barrier coatings using pigment particles. The radiative properties of the pigment particles were evaluated theoretically, and the optimum particle size was decided from the absorption efficiency and the back-scattering efficiency. UV barrier coatings were prepared with zinc oxide (ZnO) and titanium dioxide (TiO2). The transmittance of the UV barrier coating was calculated theoretically. The radiative transfer in the UV barrier coating was modeled using the radiation element method by ray emission model (REM2). In order to validate the calculated results, the transmittances of these coatings were measured by a spectrophotometer. A UV barrier coating with a low UV transmittance and high VIS transmittance could be achieved. The calculated transmittance showed a similar spectral tendency with the measured one. The use of appropriate particles with optimum size, coating thickness and volume fraction will result in effective UV barrier coatings. UV barrier coatings can be achieved by the application of optical engineering.

  9. Coupled exposure to ingredients of cosmetic products: III. Ultraviolet filters.

    Science.gov (United States)

    Uter, Wolfgang; Gonçalo, Margarida; Yazar, Kerem; Kratz, Eva-Maria; Mildau, Gerd; Lidén, Carola

    2014-09-01

    The use of cosmetics exposes consumers to mixtures of ingredients, many of which are potential allergens. Ultraviolet (UV) filters are used not just in sunscreens, but also in other products. Many UV filters are known contact allergens and photoallergens. To examine the pattern of co-exposure to UV filters in cosmetics. A survey of products marketed in Germany, conducted in 2006-2009 by the Chemical and Veterinary Investigation Office in Karlsruhe, identified 4447 products (of all 5667 cosmetic products examined) (i) that were categorizable according to Annex I to the Cosmetics Directive, and (ii) with information on the presence of UV filters or zinc oxide. The occurrence and co-occurrence of UV filters were analysed and presented in tabular and graphical format. UV filters or zinc oxide were present in 22.5% of all 4447 products, ranging from almost 100% in sunscreens to a few per cent in, for example, some hair products; they were absent in two product categories. Frequently, several different UV filters were included in one product, for example in sunscreens (median 4) and in perfumes (median 3). The overall most frequent UV filters were butyl methoxydibenzoylmethane and titanium dioxide, combined mostly with octocrylene in sunscreens and with ethylhexyl methoxycinnamate in creams. The frequent co-occurrence of UV filters in cosmetic products possibly facilitates sensitization, and may explain why patients often react to chemically unrelated UV filters. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. BigBOSS: The Ground-Based Stage IV BAO Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, David; Bebek, Chris; Heetderks, Henry; Ho, Shirley; Lampton, Michael; Levi, Michael; Mostek, Nick; Padmanabhan, Nikhil; Perlmutter, Saul; Roe, Natalie; Sholl, Michael; Smoot, George; White, Martin; Dey, Arjun; Abraham, Tony; Jannuzi, Buell; Joyce, Dick; Liang, Ming; Merrill, Mike; Olsen, Knut; Salim, Samir

    2009-04-01

    The BigBOSS experiment is a proposed DOE-NSF Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with an all-sky galaxy redshift survey. The project is designed to unlock the mystery of dark energy using existing ground-based facilities operated by NOAO. A new 4000-fiber R=5000 spectrograph covering a 3-degree diameter field will measure BAO and redshift space distortions in the distribution of galaxies and hydrogen gas spanning redshifts from 0.2< z< 3.5. The Dark Energy Task Force figure of merit (DETF FoM) for this experiment is expected to be equal to that of a JDEM mission for BAO with the lower risk and cost typical of a ground-based experiment.

  11. Biological Sensors for Solar Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    André P. Schuch

    2011-04-01

    Full Text Available Solar ultraviolet (UV radiation is widely known as a genotoxic environmental agent that affects Earth ecosystems and the human population. As a primary consequence of the stratospheric ozone layer depletion observed over the last decades, the increasing UV incidence levels have heightened the concern regarding deleterious consequences affecting both the biosphere and humans, thereby leading to an increase in scientific efforts to understand the role of sunlight in the induction of DNA damage, mutagenesis, and cell death. In fact, the various UV-wavelengths evoke characteristic biological impacts that greatly depend on light absorption of biomolecules, especially DNA, in living organisms, thereby justifying the increasing importance of developing biological sensors for monitoring the harmful impact of solar UV radiation under various environmental conditions. In this review, several types of biosensors proposed for laboratory and field application, that measure the biological effects of the UV component of sunlight, are described. Basically, the applicability of sensors based on DNA, bacteria or even mammalian cells are presented and compared. Data are also presented showing that on using DNA-based sensors, the various types of damage produced differ when this molecule is exposed in either an aqueous buffer or a dry solution. Apart from the data thus generated, the development of novel biosensors could help in evaluating the biological effects of sunlight on the environment. They also emerge as alternative tools for using live animals in the search for protective sunscreen products.

  12. Ultraviolet disinfection of treated municipal wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Vander Laan, H; Cairns, B

    1993-12-31

    A wastewater disinfection system developed by a Canadian company, Trojan Technologies Inc., was discussed. Disinfection for pathogen reduction prior to discharge of treated municipal wastewater back into rivers and lakes has been either ignored or treated by the use of chemicals. In 1979 the first pilot ultraviolet (UV) wastewater disinfection system was established. Since then, over 500 municipal UV installations have been commissioned. The largest installation can process 212 million gallons of water per day. The advantages of UV as a disinfectant are: (1) It is more effective than chlorine. (2) There are no mutagenic/carcinogenic byproducts formed with UV. (3) No toxic chemical residuals are discharged. (4) UV is safe to both the operators and the public. (5) It is cost effective. Europe has not been as active in wastewater disinfection as has North America. One result of the absence of wastewater disinfection in Europe is that the Rhine River, for example, carries 50 million salmonella per second. Disinfection of wastewater effluents is, of course, indispensable in protecting our drinking water supply. 2 figs.

  13. Effects of Eaf2 gene knockout on cataract induced by ultraviolet irradiation in mice

    Directory of Open Access Journals (Sweden)

    Yan-Hua Jiang

    2016-02-01

    Full Text Available AIM:To evaluate the effects of Eaf2 gene knockout on cataract in mice induced by ultraviolet irradiation.METHODS:Fifteen wild type mice were used as the control group, and 10 Eaf2 KO mice were used as the experimental group. The 14-week mice were taken as the research objects in the two groups. So the subgroups were: WT -nonUV, WT -UV, Eaf2 KO-nonUV and Eaf2 KO-UV, a total of 4 groups. Observe the lens of mice in vivo with slit lamp microscope, grade the lens opacity with Lens Opacities Classification System II(LOCSII. Then the mice were sacrificed by breaking the neck, the lens were removed and were observed by dark field microscopy. According to the captured images, the proportion of cataract region was analyzed using Image J software. The data of the two groups were statistically analyzed.RESULTS: The results detected by the two methods were similar. In WT-UV group and Eaf2 KO-UV group, the degree of lens opacity was significantly higher than those of WT-nonUV group and Eaf2 KO-nonUV group. The lens opacity of WT-UV group was significantly higher than that in Eaf2 KO-UV group, and the difference was statistically significant(PCONCLUSION: Ultraviolet radiation can lead to the formation of cataract in mice. Eaf2 protein can promote the formation of cataract in mice caused by ultraviolet.

  14. Induction of prophages in spores of Bacillus subtilis by ultraviolet irradiation from synchrotron orbital radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sadaie, Y.; Kada, T.; Ohta, Y. (National Inst. of Genetics, Mishima, Shizuoka (Japan)); Kobayashi, K.; Hieda, K.; Ito, T.

    1984-06-01

    Prophages were induced from Bacillus subtilis spores lysogenic with SP02 by ultraviolet (160 nm to 240 nm) irradiation from synchrotron orbital radiation (SR UV). SR UV at around 220 nm was most effective in the inactivation of spores and prophage induction from lysogenic spores, suggesting that the lesions are produced on the DNA molecule which eventually induces signals to inactivate the phage repressor.

  15. ASSESSING THE EFFECTIVENESS OF LOW PRESSURE ULTRAVIOLET LIGHT FOR INACTIVATING HELICOBACTER PYLORI

    Science.gov (United States)

    Three strains of Helicobacter pylori were exposed to ultraviolet (UV) light from a low-pressure source to determine log inactivation versus applied fluence. Results indicate that H. pylori is readily inactivated at UV fluences typically used in water treatment r...

  16. Do zooplankton contribute to an ultraviolet clear-water phase in lakes?

    NARCIS (Netherlands)

    Williamson, C.E.; Lange, de H.J.; Leech, D.M.

    2007-01-01

    Seasonal increases in the ultraviolet (UV) transparency of the surface waters of an oligotrophic lake in Pennsylvania suggest that clear-water phase (CWP) events similar to those previously observed for visible light also exist for the potentially damaging UV wavelengths. Seasonal increases in

  17. Ultraviolet radiation, sun and tanning salons; Ultrafiolett straaling, sol og solarier

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The pamphlet gives some information about ultraviolet radiation (UV), UV-sources and health effects, tanning in artificial and natural sun. It also includes some sun protection advice. It is intended mainly for persons inspecting artificial tanning units and for the owners of tanning salons. (Author)

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

    CSIR Research Space (South Africa)

    Wright, CY

    2011-07-01

    Full Text Available The detrimental effects of excess personal solar ultraviolet (UV) radiation exposure include sunburn, immunosuppression and skin cancer. In South Africa, individuals with minimum natural protection from melanin, including fair-skinned individuals...

  19. Design, Fabrication, and Analysis of High-Performance UV Band-pass filters

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA’s strategic mission concept, ATLAST (Advanced Technology Large-Aperture Space Telescope), is a telescope merging ultraviolet (UV) astrophysics and visible...

  20. The First JFET-based Silicon Carbide Active Pixel Sensor UV Imager, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Solar-blind ultraviolet (UV) imaging is critically important in the fields of space astronomy, national defense, and bio-chemistry. United Silicon Carbide, Inc....

  1. The First JFET-Based Silicon Carbide Active Pixel Sensor UV Imager, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Solar-blind ultraviolet (UV) imaging is needed in the fields of astronomy, national defense, and bio-chemistry. United Silicon Carbide, Inc. proposes to develop a...

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

    Science.gov (United States)

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

    2008-11-01

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

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

    International Nuclear Information System (INIS)

    Cooley, N.M.

    2002-01-01

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

  4. The height variation of supergranular velocity fields determined from simultaneous OSO 8 satellite and ground-based observations

    Science.gov (United States)

    November, L. J.; Toomre, J.; Gebbie, K. B.; Simon, G. W.

    1979-01-01

    Results are reported for simultaneous satellite and ground-based observations of supergranular velocities in the sun, which were made using a UV spectrometer aboard OSO 8 and a diode-array instrument operating at the exit slit of an echelle spectrograph attached to a vacuum tower telescope. Observations of the steady Doppler velocities seen toward the limb in the middle chromosphere and the photosphere are compared; the observed spectral lines of Si II at 1817 A and Fe I at 5576 A are found to differ in height of formation by about 1400 km. The results show that supergranular motions are able to penetrate at least 11 density scale heights into the middle chromosphere, that the patterns of motion correlate well with the cellular structure seen in the photosphere, and that the motion increases from about 800 m/s in the photosphere to at least 3000 m/s in the middle chromosphere. These observations imply that supergranular velocities should be evident in the transition region and that strong horizontal shear layers in supergranulation should produce turbulence and internal gravity waves.

  5. Asteroseismology of solar-type stars with Kepler: III. Ground-based data

    DEFF Research Database (Denmark)

    Karoff, Christoffer; Molenda-Żakowicz , J.

    2010-01-01

    We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than a thousand objects which are the subject of an intensive study by the Kepler Asteroseis......We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than a thousand objects which are the subject of an intensive study by the Kepler...

  6. Status of advanced ground-based laser interferometers for gravitational-wave detection

    International Nuclear Information System (INIS)

    Dooley, K L; Akutsu, T; Dwyer, S; Puppo, P

    2015-01-01

    Ground-based laser interferometers for gravitational-wave (GW) detection were first constructed starting 20 years ago and as of 2010 collection of several years’ worth of science data at initial design sensitivities was completed. Upgrades to the initial detectors together with construction of brand new detectors are ongoing and feature advanced technologies to improve the sensitivity to GWs. This conference proceeding provides an overview of the common design features of ground-based laser interferometric GW detectors and establishes the context for the status updates of each of the four gravitational-wave detectors around the world: Advanced LIGO, Advanced Virgo, GEO 600 and KAGRA. (paper)

  7. Status of advanced ground-based laser interferometers for gravitational-wave detection

    Science.gov (United States)

    Dooley, K. L.; Akutsu, T.; Dwyer, S.; Puppo, P.

    2015-05-01

    Ground-based laser interferometers for gravitational-wave (GW) detection were first constructed starting 20 years ago and as of 2010 collection of several years’ worth of science data at initial design sensitivities was completed. Upgrades to the initial detectors together with construction of brand new detectors are ongoing and feature advanced technologies to improve the sensitivity to GWs. This conference proceeding provides an overview of the common design features of ground-based laser interferometric GW detectors and establishes the context for the status updates of each of the four gravitational-wave detectors around the world: Advanced LIGO, Advanced Virgo, GEO 600 and KAGRA.

  8. Photodetector of ultraviolet radiation

    International Nuclear Information System (INIS)

    Dorogan, V.; Branzari, V.; Vieru, T.; Manole, M.; Canter, V.

    2000-01-01

    The invention relates to photodetectors on base of semiconductors of ultraviolet radiation and may be used in optoelectronic system for determining the intensity and the dose of ultraviolet radiation emitted by the Sun or other sources. Summary of the invention consists in the fact that in the photodetector of ultraviolet radiation the superficial potential barrier is divided into two identical elements, electrically isolated each of the other, one of them being covered with a layer of transparent material for visible and infrared radiation and absorption the ultra violet radiation. The technical result consists in mutual compensation of visible and infrared components of the radiation spectrum

  9. Tanning lamps ultraviolet emissions and compliance with technical standards

    International Nuclear Information System (INIS)

    Bonino, A.; Facta, S.; Saudino, S.; Anglesio, L.; D'Amore, G.

    2009-01-01

    In this work the compliance of tanning lamps with technical standards EN 60335-2-27 'Household and similar electrical appliances-Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation' was analysed. Results of this analysis showed that none of the examined technical documentation produced by the lamps manufacturers is fully compliant with the standard technique. Furthermore data reported in the same manuals, such as effective radiant exposure or irradiance, would indicate that these sources may be the cause of undue exposure to ultraviolet (UV) radiation. For this reason a measurement campaign on UV lamps used in tanning salons was organised. The first results of these measurements seem to confirm the doubts raised from the analysis of the lamp manuals: the use of a tanning lamp can lead to UV radiation exposure levels higher than reference maximum values recommended by EN 60335-2-27. (authors)

  10. Ultraviolet radiation and air contamination during total hip replacement

    International Nuclear Information System (INIS)

    Carlsson, A.S.; Nilsson, B.; Walder, M.H.; Osterberg, K.

    1986-01-01

    Ultraviolet (uv) radiation of the operating room was assessed bacteriologically in an open randomized study of 30 total hip procedures. Volumetric air-sampling demonstrated that the number of colony forming units (cfu m-3) were significantly reduced (P less than 0.001) by uv light, both close to the wound and in the periphery of the operating room. No adverse effects of the uv-irradiation were observed either in the patients or the staff. In operating rooms fitted with a zonal ventilation system and with an air change rate of about 70 h-1, the addition of uv irradiation during surgery may achieve ultra clean air. However, in conventionally ventilated operating rooms uv-irradiation alone is probably not sufficient to do so

  11. Ultraviolet light curves of U Geminorum and VW Hydri

    International Nuclear Information System (INIS)

    Wu, C.-C.; Panek, R.J.; Holm, A.V.; Schiffer, F.H. III

    1982-01-01

    Ultraviolet light curves have been obtained for the quiescent dwarf novae U Gem and VW Hyi. The amplitude of the hump associated with the accretion hot spot is much smaller in the UV than in the visible. This implies that the bright spot temperature is roughly 12000 K if it is optically thick. A hotter spot would have to be optically thin in the near UV. The flux distribution of U Gem in quiescence cannot be fitted by model spectra of steady state, viscous accretion disks. The absolute luminosity, the flux distribution, and the far UV spectrum suggest that the primary star is visible in the far UV. The optical-UV flux distribution of VW Hyi could be matched roughly by the authors' model accretion disks, but the fitting is poorly constrained due to the uncertainty in its distance. (Auth.)

  12. Solution processable organic/inorganic hybrid ultraviolet photovoltaic detector

    Directory of Open Access Journals (Sweden)

    Xiaopeng Guo

    2016-05-01

    Full Text Available Ultraviolet (UV photodetector is a kind of important optoelectronic device which can be widely used in scientific and engineering fields including astronomical research, environmental monitoring, forest-fire prevention, medical analysis, and missile approach warning etc. The development of UV detector is hindered by the acquirement of stable p-type materials, which makes it difficult to realize large array, low-power consumption UV focal plane array (FPA detector. Here, we provide a novel structure (Al/Poly(9,9-di-n-octylfuorenyl-2,7-diyl(PFO/ZnO/ITO to demonstrate the UV photovoltaic (PV response. A rather smooth surface (RMS roughness: 0.28 nm may be reached by solution process, which sheds light on the development of large-array, light-weight and low-cost UV FPA detectors.

  13. Effect of ultraviolet light irradiation on amorphous carbon nitride films

    International Nuclear Information System (INIS)

    Zhang, M.; Nakayama, Y.

    1997-01-01

    The amorphous carbon nitride films were produced using electron cyclotron resonance nitrogen plasma with various mixtures of N 2 and CH 4 gases. The dependence of film structures on the nitrogen incorporation and the structural modifications of the film due to ultraviolet (UV) light irradiation were investigated using infrared and UV-VIS spectroscopy. It is found that UV irradiation results in the decrease of CH bonding, increase of CC and CN double bonding in the film and increase of the optical band gap of the film. It appears that both bond removal and reordering have taken place as a result of UV irradiation. The structural modifications due to nitrogen incorporation and UV light irradiation are explained by a cluster model. copyright 1997 American Institute of Physics

  14. Ultraviolet-based therapy for vitiligo: What′s new?

    Directory of Open Access Journals (Sweden)

    Iltefat H Hamzavi

    2012-01-01

    Full Text Available Vitiligo is an ancient disease in which depigmented and hypopigmented macules appear on the skin. It is a disfiguring condition that may lead to severe psychological trauma. Among the many treatment modalities available for use in vitiligo, those using light therapy, and in particular ultraviolet (UV light, are some of the most effective treatments. UV-based therapy includes phototherapy (narrowband UVB, photochemotherapy (psoralens with UVA, and targeted phototherapy (excimer laser and excimer lamp. It is important for any practitioner of UV-based therapy to understand the efficacy of each treatment type, as well as their respective adverse effects. In order to take full advantage of UV-based therapy, location, dosing, and photoadaptation must also be taken into account. This review discusses the various UV-based therapeutic options, adjuvant therapies, optimal dosing guidelines, appropriate patient selection, future treatment options, and recommendations based upon the current evidence and the authors′ experience with vitiligo.

  15. Deep UV LEDs

    Science.gov (United States)

    Han, Jung; Amano, Hiroshi; Schowalter, Leo

    2014-06-01

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

  16. Maps of ultraviolet radiation in Costa Rica

    International Nuclear Information System (INIS)

    Wright, Jaime

    2009-01-01

    Ultraviolet radiation (UV) has contributed relatively little energy to the solar spectrum; but is important, because it is biologically active. The software Surfer 8 has created maps designed of the territory of Costa Rica to assess the maximum levels of solar UV radiation on a horizontal plane. The data were used in creating the maps, were predicted at local noon in eighty-three locations scattered across the country, with a spectral atmospheric model which is physically established. The model has used as input data: the date and time, the location identified by latitude, longitude and height of land above sea level, the value of the vertical column ozone, surface albedo and atmospheric turbidity parameters. The estimate differs by 3% of the measurements made in situ, which agrees with the experimental data. The model has used the data estimation of UV radiation, clear sky conditions, which is the condition where you get the maximum energy possible in each locality. This is of fundamental importance when assessing the adverse effects on human health, leads the maximum intensity in this important solar spectrum band. A larger increase of 23% has presented in the UV radiation with altitude obtaining the hills and mountains the highest rates and places located at sea level and the lowest cost, the indices. The annual variation analysis has revealed an increase greater than 27% from the month of lowest UV radiation (December) and the month of greatest UV radiation (April). The issue is of particular interest because of the increasing number of people moving at different times of the year, altitudes over 2000 m altitude, in activities relating to tourism and employment. These individuals are significant increases in levels of UV solar radiation under conditions of clear skies. (author) [es

  17. 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)

  18. Ground-Based VIS/NIR Reflectance Spectra of 25143 Itokawa: What Hayabusa will See and How Ground-Based Data can Augment Analyses

    Science.gov (United States)

    Vilas, Faith; Abell, P. A.; Jarvis, K. S.

    2004-01-01

    Planning for the arrival of the Hayabusa spacecraft at asteroid 25143 Itokawa includes consideration of the expected spectral information to be obtained using the AMICA and NIRS instruments. The rotationally-resolved spatial coverage the asteroid we have obtained with ground-based telescopic spectrophotometry in the visible and near-infrared can be utilized here to address expected spacecraft data. We use spectrophotometry to simulate the types of data that Hayabusa will receive with the NIRS and AMICA instruments, and will demonstrate them here. The NIRS will cover a wavelength range from 0.85 m, and have a dispersion per element of 250 Angstroms. Thus, we are limited in coverage of the 1.0 micrometer and 2.0 micrometer mafic silicate absorption features. The ground-based reflectance spectra of Itokawa show a large component of olivine in its surface material, and the 2.0 micrometer feature is shallow. Determining the olivine to pyroxene abundance ratio is critically dependent on the attributes of the 1.0- and 2.0 micrometer features. With a cut-off near 2,1 micrometer the longer edge of the 2.0- feature will not be obtained by NIRS. Reflectance spectra obtained using ground-based telescopes can be used to determine the regional composition around space-based spectral observations, and possibly augment the longer wavelength spectral attributes. Similarly, the shorter wavelength end of the 1.0 micrometer absorption feature will be partially lost to the NIRS. The AMICA filters mimic the ECAS filters, and have wavelength coverage overlapping with the NIRS spectral range. We demonstrate how merging photometry from AMICA will extend the spectral coverage of the NIRS. Lessons learned from earlier spacecraft to asteroids should be considered.

  19. THE ABSOLUTE MAGNITUDES OF TYPE Ia SUPERNOVAE IN THE ULTRAVIOLET

    International Nuclear Information System (INIS)

    Brown, Peter J.; Roming, Peter W. A.; Ciardullo, Robin; Gronwall, Caryl; Hoversten, Erik A.; Pritchard, Tyler; Milne, Peter; Bufano, Filomena; Mazzali, Paolo; Elias-Rosa, Nancy; Filippenko, Alexei V.; Li Weidong; Foley, Ryan J.; Hicken, Malcolm; Kirshner, Robert P.; Gehrels, Neil; Holland, Stephen T.; Immler, Stefan; Phillips, Mark M.; Still, Martin

    2010-01-01

    We examine the absolute magnitudes and light-curve shapes of 14 nearby (redshift z = 0.004-0.027) Type Ia supernovae (SNe Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way extinction law and one for the Large Magellanic Cloud that has been modified by circumstellar scattering. We find very different behavior in the near-UV filters (uvw1 rc covering ∼2600-3300 A after removing optical light, and u ∼ 3000-4000 A) compared to a mid-UV filter (uvm2 ∼2000-2400 A). The uvw1 rc - b colors show a scatter of ∼0.3 mag while uvm2-b scatters by nearly 0.9 mag. Similarly, while the scatter in colors between neighboring filters is small in the optical and somewhat larger in the near-UV, the large scatter in the uvm2 - uvw1 colors implies significantly larger spectral variability below 2600 A. We find that in the near-UV the absolute magnitudes at peak brightness of normal SNe Ia in our sample are correlated with the optical decay rate with a scatter of 0.4 mag, comparable to that found for the optical in our sample. However, in the mid-UV the scatter is larger, ∼1 mag, possibly indicating differences in metallicity. We find no strong correlation between either the UV light-curve shapes or the UV colors and the UV absolute magnitudes. With larger samples, the UV luminosity might be useful as an additional constraint to help determine distance, extinction, and metallicity in order to improve the utility of SNe Ia as standardized candles.

  20. Opsin cDNA sequences of a UV and green rhodopsin of the satyrine butterfly Bicyclus anynana.

    NARCIS (Netherlands)

    Vanhoutte, K.J.A.; Eggen, B.J.L.; Janssen, J.J.M.; Stavenga, D.G.

    2002-01-01

    The cDNAs of an ultraviolet (UV) and long-wavelength (LW) (green) absorbing rhodopsin of the bush brown Bicyclus anynana were partially identified. The UV sequence, encoding 377 amino acids, is 76-79% identical to the UV sequences of the papilionids Papilio glaucus and Papilio xuthus and the moth

  1. Opsin cDNA sequences of a UV and green rhodopsin of the satyrine butterfly Bicyclus anynana

    NARCIS (Netherlands)

    Vanhoutte, Kürt; Eggen, BJL; Janssen, JJM; Stavenga, DG

    The cDNAs of an ultraviolet (UV) and long-wavelength (LW) (green) absorbing rhodopsin of the bush brown Bicyclus anynana were partially identified. The UV sequence, encoding 377 amino acids, is 76-79% identical to the UV sequences of the papilionids Papilio glaucus and Papilio xuthus and the moth

  2. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

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

  3. The impact of ultraviolet therapy on stratum corneum ceramides and barrier function

    DEFF Research Database (Denmark)

    Jungersted, Jakob Mutanu; Høgh, Julie Kaae; Hellgren, Lars

    2011-01-01

    therapy in dermatological patients on ceramides and skin barrier function.We found that UV light treatment does not change the ratio of important stratum corneum lipids, but we confirm earlier findings of decreased susceptibility to irritants after UV- therapy.......The ceramide profile as well as the barrier function is known to be deteriorated in atopic eczema and psoriasis, and ultraviolet (UV) light is known to improve the barrier function. The impact of UV light on ceramides, however, is not clarified.The aim of this study was to examine the effect of UV...

  4. The impact of ultraviolet therapy on stratum corneum ceramides and barrier function

    DEFF Research Database (Denmark)

    Jungersted, Jakob Mutanu; Høgh, Julie Kaae; Hellgren, Lars

    2011-01-01

    therapy in dermatological patients on ceramides and skin barrier function. We found that UV light treatment does not change the ratio of important stratum corneum lipids, but we confirm earlier findings of decreased susceptibility to irritants after UV- therapy.......The ceramide profile as well as the barrier function is known to be deteriorated in atopic eczema and psoriasis, and ultraviolet (UV) light is known to improve the barrier function. The impact of UV light on ceramides, however, is not clarified. The aim of this study was to examine the effect of UV...

  5. Impact of Ultraviolet-Blocking Plastic Films on Insect Vectors of Virus Diseases Infesting Crisp Lettuce

    OpenAIRE

    Díaz Desani, Beatriz M.; Biurrun, R.; Moreno, Aránzazu; Nebreda, Miguel; Fereres, Alberto

    2006-01-01

    Ultraviolet (UV)-absorbing plastic films are being used as a photoselective barrier to control insect vectors and associated virus diseases in different horticultural crops. A 2-year experiment was carried out in northeastern Spain (Navarra) to evaluate the impact of a UV-blocking film (AD-IR AV) on the population density of insect pests and the spread of insect-transmitted virus diseases associated with head lettuce [Lactuca sativa (L.)]. Results showed that the UV-absorbing plastic film did...

  6. Health effects of UV-B exposure; with special emphasis on the immune system

    NARCIS (Netherlands)

    Goettsch W; Garssen J; de Gruijl FR; van Loveren H

    1992-01-01

    As a results of a depletion of atmospheric ozone all living organisms on the earth"s surface may be exposed to increased amounts of ultraviolet radiation. In man, ultraviolet radiation (UVR, especially UV-B) can cause, in addition to some beneficial effects like vitaming D formation,

  7. The SAURON project : XVIII. The integrated UV-line-strength relations of early-type galaxies

    NARCIS (Netherlands)

    Bureau, Martin; Jeong, Hyunjin; Yi, Sukyoung K.; Schawinski, Kevin; Houghton, Ryan C. W.; Davies, Roger L.; Bacon, Roland; Cappellari, Michele; de Zeeuw, P. Tim; Emsellem, Eric; Falcon-Barroso, Jesus; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M.; Peletier, Reynier F.; Sarzi, Marc; Sohn, Young-Jong; Thomas, Daniel; van den Bosch, Remco C. E.; van de Ven, Glenn

    Using far-ultraviolet (FUV) and near-ultraviolet (NUV) photometry from guest investigator programmes on the Galaxy Evolution Explorer (GALEX) satellite, optical photometry from the MDM Observatory and optical integral-field spectroscopy from SAURON, we explore the UV-line-strength relations of the

  8. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Chevremont, A.-C., E-mail: anne-celine.chevremont@imbe.fr [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France); Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Farnet, A.-M. [Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Coulomb, B.; Boudenne, J.-L. [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France)

    2012-06-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO{sub 2}. - Highlights: Black-Right-Pointing-Pointer We test UV-LEDs as an urban wastewater tertiary treatment. Black-Right-Pointing-Pointer UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. Black-Right-Pointing-Pointer Coupled wavelengths have the most efficient bactericidal effect. Black-Right-Pointing-Pointer Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

  9. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    International Nuclear Information System (INIS)

    Chevremont, A.-C.; Farnet, A.-M.; Coulomb, B.; Boudenne, J.-L.

    2012-01-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO 2 . - Highlights: ► We test UV-LEDs as an urban wastewater tertiary treatment. ► UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. ► Coupled wavelengths have the most efficient bactericidal effect. ► Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

  10. Ultraviolet Flux Variation of Epsilon Aurigae

    Directory of Open Access Journals (Sweden)

    Young Woon Kang

    1990-06-01

    Full Text Available The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 Å to 3050 Å. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

  11. Take-off and Landing Using Ground Based Power - Landing Simulations Using Multibody Dynamics

    NARCIS (Netherlands)

    Wu, P.; Voskuijl, M.; Van Tooren, M.J.L.

    2014-01-01

    A novel take-off and landing system using ground based power is proposed in the EUFP7 project GABRIEL. The proposed system has the potential benefit to reduce aircraft weight, emissions and noise. A preliminary investigation of the feasibility of the structural design of the connection mechanism

  12. ForestCrowns: a software tool for analyzing ground-based digital photographs of forest canopies

    Science.gov (United States)

    Matthew F. Winn; Sang-Mook Lee; Phillip A. Araman

    2013-01-01

    Canopy coverage is a key variable used to characterize forest structure. In addition, the light transmitted through the canopy is an important ecological indicator of plant and animal habitat and understory climate conditions. A common ground-based method used to document canopy coverage is to take digital photographs from below the canopy. To assist with analyzing...

  13. Estimating and validating ground-based timber harvesting production through computer simulation

    Science.gov (United States)

    Jingxin Wang; Chris B. LeDoux

    2003-01-01

    Estimating ground-based timber harvesting systems production with an object oriented methodology was investigated. The estimation model developed generates stands of trees, simulates chain saw, drive-to-tree feller-buncher, swing-to-tree single-grip harvester felling, and grapple skidder and forwarder extraction activities, and analyzes costs and productivity. It also...

  14. On reconciling ground-based with spaceborne normalized radar cross section measurements

    DEFF Research Database (Denmark)

    Baumgartner, Francois; Munk, Jens; Jezek, K C

    2002-01-01

    This study examines differences in the normalized radar cross section, derived from ground-based versus spaceborne radar data. A simple homogeneous half-space model, indicates that agreement between the two improves as 1) the distance from the scatterer is increased; and/or 2) the extinction...

  15. Validation of the CrIS fast physical NH3 retrieval with ground-based FTIR

    NARCIS (Netherlands)

    Dammers, E.; Shephard, M.W.; Palm, M.; Cady-Pereira, K.; Capps, S.; Lutsch, E.; Strong, K.; Hannigan, J.W.; Ortega, I.; Toon, G.C.; Stremme, W.; Grutter, M.; Jones, N.; Smale, D.; Siemons, J.; Hrpcek, K.; Tremblay, D.; Schaap, M.; Notholt, J.; Willem Erisman, J.

    2017-01-01

    Presented here is the validation of the CrIS (Cross-track Infrared Sounder) fast physical NH3 retrieval (CFPR) column and profile measurements using ground-based Fourier transform infrared (FTIR) observations. We use the total columns and profiles from seven FTIR sites in the Network for the

  16. A cost-performance model for ground-based optical communications receiving telescopes

    Science.gov (United States)

    Lesh, J. R.; Robinson, D. L.

    1986-01-01

    An analytical cost-performance model for a ground-based optical communications receiving telescope is presented. The model considers costs of existing telescopes as a function of diameter and field of view. This, coupled with communication performance as a function of receiver diameter and field of view, yields the appropriate telescope cost versus communication performance curve.

  17. Retrieval of liquid water cloud properties from ground-based remote sensing observations

    NARCIS (Netherlands)

    Knist, C.L.

    2014-01-01

    Accurate ground-based remotely sensed microphysical and optical properties of liquid water clouds are essential references to validate satellite-observed cloud properties and to improve cloud parameterizations in weather and climate models. This requires the evaluation of algorithms for retrieval of

  18. Modern developments for ground-based monitoring of fire behavior and effects

    Science.gov (United States)

    Colin C. Hardy; Robert Kremens; Matthew B. Dickinson

    2010-01-01

    Advances in electronic technology over the last several decades have been staggering. The cost of electronics continues to decrease while system performance increases seemingly without limit. We have applied modern techniques in sensors, electronics and instrumentation to create a suite of ground based diagnostics that can be used in laboratory (~ 1 m2), field scale...

  19. Submillimetric motion detection with a 94 GHz ground based synthetic aperture radar

    OpenAIRE

    Martinez Cervera, Arturo; Lort Cuenca, Marc; Aguasca Solé, Alberto; Broquetas Ibars, Antoni

    2015-01-01

    The paper presents the validation and experimental assessment of a 94 GHz (W-Band) CW-FM Radar that can be configured as a Ground Based SAR for high resolution imaging and interferometry. Several experimental campaigns have been carried out to assess the capability of the system to remotely observe submillimetric deformation and vibration in infrastructures. Peer Reviewed

  20. Ground-based forest harvesting effects on soil physical properties and Douglas-fir growth.

    Science.gov (United States)

    Adrian Ares; Thomas A. Terry; Richard E. Miller; Harry W. Anderson; Barry L. Flaming

    2005-01-01

    Soil properties and forest productivity can be affected by heavy equipment used for harvest and site preparation but these impacts vary greatly with site conditions and operational practices. We assessed the effects of ground-based logging on soil physical properties and subsequent Douglas-fir [Pseudotsuga menziesii (Mirb) Franco] growth on a highly...

  1. Overview of Boundary Layer Clouds Using Satellite and Ground-Based Measurements

    Science.gov (United States)

    Xi, B.; Dong, X.; Wu, P.; Qiu, S.

    2017-12-01

    A comprehensive summary of boundary layer clouds properties based on our few recently studies will be presented. The analyses include the global cloud fractions and cloud macro/micro- physical properties based on satellite measurements using both CERES-MODIS and CloudSat/Caliposo data products,; the annual/seasonal/diurnal variations of stratocumulus clouds over different climate regions (mid-latitude land, mid-latitude ocean, and Arctic region) using DOE ARM ground-based measurements over Southern great plain (SGP), Azores (GRW), and North slope of Alaska (NSA) sites; the impact of environmental conditions to the formation and dissipation process of marine boundary layer clouds over Azores site; characterizing Arctice mixed-phase cloud structure and favorable environmental conditions for the formation/maintainess of mixed-phase clouds over NSA site. Though the presentation has widely spread topics, we will focus on the representation of the ground-based measurements over different climate regions; evaluation of satellite retrieved cloud properties using these ground-based measurements, and understanding the uncertainties of both satellite and ground-based retrievals and measurements.

  2. Cellular repair and its importance for UV-induced mutations

    Energy Technology Data Exchange (ETDEWEB)

    Slamenova, D [Slovenska Akademia Vied, Bratislava (Czechoslovakia). Vyskumny Ustav Onkologicky

    1975-01-01

    Current knowledge is briefly surveyed of the mechanism of the biological repair of injuries induced in DNA cells by the action of various factors, mainly ultraviolet radiation. Genetic loci determining the sensitivity of cells to UV radiation are defined and principal reparation processes are explained; excision repair is described more fully. The role of biological repair is discussed in view of UV-induced mutations in DNA cells.

  3. UV and EB radiation processing in developing countries

    International Nuclear Information System (INIS)

    Garnett, J.L.

    1991-01-01

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

  4. Flare activity on UV Ceti: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-01-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  5. Flare activity on UV CETI: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-06-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  6. Ultraviolet photometry of the Cepheid beta Doradus from the ANS satellite

    CERN Document Server

    Lub, J; Pel, J W; Wesselius, P R

    1979-01-01

    Extensive satellite (ANS) and ground-based (VBLUW-system) photometry is presented for the Cepheid. These data cover the wavelength range 5500-1800 AA. The ANS photometry does not confirm the evidence for shock waves as found by Hutchinson et al. from OAO-2 ultraviolet photometry of beta Doradus. A comparison of the theoretical fluxes of Kurucz with the observed energy distributions of beta Doradus gives very good agreement in the wavelength range 5500-3300 AA. In the ultraviolet the agreement is still satisfactory around maximum light, but towards lower temperatures there appear discrepancies, particularly shortly after light minimum. The difference in these discrepancies on the rising and on the falling branches of the lightcurve indicates that the observed excess ultraviolet flux is probably partly due to that the observed excess ultraviolet flux is probably partly due to dynamical effects in the moving atmosphere of the Cepheid. (25 refs).

  7. Elevated aerosol layers modify the O2–O2 absorption measured by ground-based MAX-DOAS

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Ivan; Berg, Larry K.; Ferrare, Richard A.; Hair, Johnathan W.; Hostetler, Chris A.; Volkamer, Rainer

    2016-06-01

    The oxygen collisional complex (O2-O2, or O4) is a greenhouse gas, and a calibration trace gas used to infer aerosol and cloud properties by Differential Optical Absorption Spectroscopy (DOAS). Recent reports suggest the need for an O4 correction factor (CFO4) when comparing simulated and measured O4 differential slant column densities (dSCD) by passive DOAS. We investigate the sensitivity of O4 dSCD simulations at ultraviolet (360 nm) and visible (477 nm) wavelengths towards separately measured aerosol extinction profiles. Measurements were conducted by the University of Colorado 2D-MAX-DOAS instrument and NASA’s multispectral High Spectral Resolution Lidar (HSRL-2) during the Two Column Aerosol Project (TCAP) at Cape Cod, MA in July 2012. During two case study days with (1) high aerosol load (17 July, AOD ~ 0.35 at 477 nm), and (2) near molecular scattering conditions (22 July, AOD < 0.10 at 477 nm) the measured and calculated O4 dSCDs agreed within 6.4±0.4% (360 nm) and 4.7±0.6% (477 nm) if the HSRL-2 profiles were used as input to the calculations. However, if in the calculations the aerosol is confined to the surface layer (while keeping AOD constant) we find 0.53ground-based MAX-DOAS. Opportunities to identify and better characterize these layers are also discussed.

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

    Directory of Open Access Journals (Sweden)

    I. Ialongo

    2011-09-01

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

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

  9. Ultraviolet-visible spectroscopy of graphene oxides

    Directory of Open Access Journals (Sweden)

    Qi Lai

    2012-09-01

    Full Text Available Dispersions of few-layer (1-3 layers, multi-layer (4-10 layers and thick-layer (>10 layers graphene oxide (GO were prepared by a modified Hummers method with different mass ratios of KMnO4 to graphite. Ultraviolet-visible (UV-vis spectroscopic data show that few-layer GO dispersions can be distinguished from multi- and thick-layer dispersions by a more intense peak at 230 nm. Atomic force microscopy (AFM images of few-layer GO contain a single peak, those of multi-layer GO exhibit a shoulder and those of thick-layer GO do not contain a peak or shoulder. These findings allow qualitative analysis of GO dispersions. X-ray photoelectron spectra (XPS show that the change of UV-vis absorption intensity of GO is caused by a conjugative effect related to chromophore aggregation that influences the π-π* plasmon peak.

  10. Recent Advances on Endocrine Disrupting Effects of UV Filters

    Directory of Open Access Journals (Sweden)

    Jiaying Wang

    2016-08-01

    Full Text Available Ultraviolet (UV filters are used widely in cosmetics, plastics, adhesives and other industrial products to protect human skin or products against direct exposure to deleterious UV radiation. With growing usage and mis-disposition of UV filters, they currently represent a new class of contaminants of emerging concern with increasingly reported adverse effects to humans and other organisms. Exposure to UV filters induce various endocrine disrupting effects, as revealed by increasing number of toxicological studies performed in recent years. It is necessary to compile a systematic review on the current research status on endocrine disrupting effects of UV filters toward different organisms. We therefore summarized the recent advances on the evaluation of the potential endocrine disruptors and the mechanism of toxicity for many kinds of UV filters such as benzophenones, camphor derivatives and cinnamate derivatives.

  11. 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...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  13. Inactivation of airborne Enterococcus faecalis and infectious bursal disease virus using a pilot-scale ultraviolet photocatalytic oxidation scrubber

    NARCIS (Netherlands)

    Zhao, Y.; Aarnink, A.J.A.; Xin, H.

    2014-01-01

    High microbial concentrations and emissions associated with livestock houses raise health and environmental concerns. A pilot-scale ultraviolet photocatalytic (UV-PCO) scrubber was tested for its efficacy to inactivate aerosolized Enterococcus faecalis and infectious bursal disease virus (IBDV).

  14. ASSESSMENT OF THE RISK OF SOLAR ULTRAVIOLET RADIATION TO AMPHIBIANS: III. PREDICTION OF IMPACTS IN SELECTED NORTHERN MIDWESTERN WETLANDS

    Science.gov (United States)

    The deleterious effects of solar ultraviolet radiation, especially the UV-B portion of sunlight, have been hypothesized to reduce survival, increase the frequency of malformations, and contribute to the apparent worldwide decline of many amphibian species.

  15. Ultraviolet Light Surface Treatment as an Environmentally Benign Process for Production, Maintenance and Repair of Military Composite Structures

    National Research Council Canada - National Science Library

    Drzal, Lawrence T

    2002-01-01

    The principal objective of this work is to develop a low-cost, high-speed, environmentally benign, dry surface treatment method for production, and repair of military composite structures using ultraviolet (UV...

  16. UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces

    International Nuclear Information System (INIS)

    Lochmann, E.R.; Lochmann, G.

    1997-01-01

    The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.) [de

  17. Classical ultraviolet photoelectron spectroscopy of polymers

    International Nuclear Information System (INIS)

    Salaneck, W.R.

    2009-01-01

    Although X-ray photoelectron spectroscopy of polymers was well established by Clark and coworkers in the 1970s, ultraviolet photoelectron spectroscopy of polymer films, was developed later. Previous to the 1970s, the first attempts to use ultraviolet light on polymer films took the form of appearance potential (valence band edge) measurements. Only some years later could the full valence band region of thin polymer films, including insulating polymers, semiconducting polymers and electrically conducting polymers. The development of what might be termed 'classical ultraviolet photoelectron spectroscopy' of polymer films may be loosely based upon a variety of issues, including adapting thin polymer film technology to ultra high vacuum studies, the widespread use of helium resonance lamps for studies of solid surfaces, the combined advent of practical and sufficient theoretical-computational methods. The advent of, and the use of, easily available synchrotron radiation for multi-photon spectroscopies, nominally in the area of the near UV, is not included in the term 'classical'. At the same time, electrically conducting polymers were discovered, leading to applications of the corresponding semiconducting polymers, which added technologically driven emphasis to this development of ultraviolet photoelectron spectroscopy for polymer materials. This paper traces a limited number of highlights in the evolution of ultraviolet photoelectron spectroscopy of polymers, from the 1970s through to 2008. Also, since this issue is dedicated to Prof. Kazuhiko Seki, who has been a friend and competitor for over two decades, the author relies on some of Prof. Seki's earlier research, unpublished, on who-did-what-first. Prof. Seki's own contributions to the field, however, are discussed in other articles in this issue.

  18. Remotely Triggered Solar Blind Signaling Using Deep Ultraviolet (UV) LEDs

    Science.gov (United States)

    2011-06-01

    observer, providing a means of visual communication even if the direct path is blocked...propogate toward the observer, providing a means of visual communication even if the direct path is blocked. 47 B. NLOS DETECTION USING LOCK-IN

  19. Ultraviolet (UV)-Curable Coatings for Aerospace Applications

    Science.gov (United States)

    2012-08-31

    implement hexavalent chromium reduction, any new primers introduced would have to be chrome -free. Formulating a chrome -free primer that can provide...5955 All painting was done on panels of 2024-T3 Aluminum (4" x 6" x 0.020") with ¼” hole in center of short side, coated with an Alodine 1200S chrome

  20. Spec UV-Vis: An Ultraviolet-Visible Spectrophotometer Simulation

    Science.gov (United States)

    Papadopoulos, N.; Limniou, Maria; Koklamanis, Giannis; Tsarouxas, Apostolos; Roilidis, Mpampis; Bigger, Stephen W.

    2001-11-01

    The software and its accompanying manual can be used to illustrate the recording of an absorption spectrum and the Beer-Lambert law (5-7) as well as various aspects of acid-base indicators such as the spectrophotometric determination of pKa (8), the isosbestic point (6, 9), and distribution diagrams (10, 11). Literature Cited Shiowatana, J. J. Chem. Educ. 1997, 74, 730. Altemose, I. R. J. Chem. Educ. 1986, 63, A216, A262. Piepmeier, E. H. J. Chem. Educ. 1973, 50, 640. Lott, P. F. J. Chem. Educ. 1968, 45, A89, A169, A182, A273. Skoog, D. A.; West, D. M.; Holler, F. J. Fundamentals of Analytical Chemistry, 7th ed.; Saunders College Publishing: Fort Worth, TX, 1996, Chapters 22-24. Christian, G. D. Analytical Chemistry, 5th ed.; Wiley: New York, 1994; Chapter 14. Kennedy, J. H. Analytical Chemistry--Principles, 2nd ed.; Saunders College Publishing: New York, 1990; Chapters 11,12. Patterson, G. S. J. Chem. Educ. 1999, 76, 395. Harris, D. C. Quantitative Chemical Analysis, 5th ed.; Freeman: New York, 1997; Chapters 19, 20. Butler, J. N. Ionic Equilibrium--A Mathematical Approach; Addison-Wesley: Reading, MA, 1964; Chapter 5. Sawyer, C. A.; McCarty, P. L.; Parkin, G. F. Chemistry for Environmental Engineering, 4th ed.; McGraw-Hill: Singapore, 1994; Chapter 4.

  1. Demonstration test and evaluation of Ultraviolet/Ultraviolet Catalyzed Peroxide Oxidation for Groundwater Remediation at Oak Ridge K-25 Site

    International Nuclear Information System (INIS)

    1994-03-01

    We demonstrated, tested and evaluated a new ultraviolet (UV) lamp integrated with an existing commercial technology employing UV catalyzed peroxide oxidation to destroy organics in groundwater at an Oak Ridge K-25 site. The existing commercial technology is the perox-pure trademark process of Peroxidation Systems Incorporated (PSI) that employs standard UV lamp technology to catalyze H 2 O 2 into OH radicals, which attack many organic molecules. In comparison to classical technologies for remediation of groundwater contaminated with organics, the perox-pure trademark process not only is cost effective but also reduces contaminants to harmless by-products instead of transferring the contaminants from one medium to another. Although the perox-pure trademark process is cost effective against many organics, it is not effective for some organic contaminants of interest to DOE such as TCA, which has the highest concentration of the organics at the K-25 test site. Contaminants such as TCA are treated more readily by direct photolysis using short wavelength UV light. WJSA has been developing a unique UV lamp which is very efficient in the short UV wavelength region. Consequently, combining this UV lamp with the perox-pure trademark process results in a means for treating essentially all organic contaminants. In the program reported here, the new UV lamp lifetime was improved and the lamp integrated into a PSI demonstration trailer. Even though this UV lamp operated at less than optimum power and UV efficiency, the destruction rate for the highest concentration organic (TCA) was more than double that of the commercial unit. An optimized UV lamp may double again the destruction rate; i.e., a factor of four greater than the commercial system. The demonstration at K-25 included tests with (1) the commercial PSI system, (2) the new UV lamp-based system and (3) the commercial PSI and new UV lamp systems in series

  2. REPRESSOR OF ULTRAVIOLET-B PHOTOMORPHOGENESIS function allows efficient phototropin mediated ultraviolet-B phototropism in etiolated seedlings.

    Science.gov (United States)

    Vanhaelewyn, Lucas; Schumacher, Paolo; Poelman, Dirk; Fankhauser, Christian; Van Der Straeten, Dominique; Vandenbussche, Filip

    2016-11-01

    Ultraviolet B (UV-B) light is a part of the solar radiation which has significant effects on plant morphology, even at low doses. In Arabidopsis, many of these morphological changes have been attributed to a specific UV-B receptor, UV resistance locus 8 (UVR8). Recent findings showed that next to phototropin regulated phototropism, UVR8 mediated signaling is able of inducing directional bending towards UV-B light in etiolated seedlings of Arabidopsis, in a phototropin independent manner. In this study, kinetic analysis of phototropic bending was used to evaluate the relative contribution of each of these pathways in UV-B mediated phototropism. Diminishing UV-B light intensity favors the importance of phototropins. Molecular and genetic analyses suggest that UV-B is capable of inducing phototropin signaling relying on phototropin kinase activity and regulation of NPH3. Moreover, enhanced UVR8 responses in the UV-B hypersensitive rup1rup2 mutants interferes with the fast phototropin mediated phototropism. Together the data suggest that phototropins are the most important receptors for UV-B induced phototropism in etiolated seedlings, and a RUP mediated negative feedback pathway prevents UVR8 signaling to interfere with the phototropin dependent response. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Ground-Based Global Navigation Satellite System (GNSS) GLONASS Broadcast Ephemeris Data (hourly files) from NASA CDDIS

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset consists of ground-based Global Navigation Satellite System (GNSS) GLObal NAvigation Satellite System (GLONASS) Broadcast Ephemeris Data (hourly files)...

  4. Detection of broad ultraviolet Fe II lines in the spectrum of NGC 1068

    International Nuclear Information System (INIS)

    Snijders, M.A.J.; Netzer, Hagai; Boksenberg, A.

    1986-01-01

    Ultraviolet observations of the nucleus of NGC 1068, obtained by the IUE over a period of 5 yr, are combined to give a high signal-to-noise spectrum of this source. The ultraviolet stellar continuum, obtained by comparison with ground-based data, is subtracted to show the nuclear non-stellar component. The resulting spectrum shows clearly the presence of strong broad FeII emission bands similar to those observed in many broad-line objects. Broad profiles are also seen in other strong emission lines. These observations confirm the recent discovery of an optical Seyfert type 1 spectrum in NGC 1068. (author)

  5. A Fourier transform spectrometer for visible and near ultra-violet measurements of atmospheric absorption

    Science.gov (United States)

    Parsons, C. L.; Gerlach, J. C.; Whitehurst, M.

    1982-01-01

    The development of a prototype, ground-based, Sun-pointed Michelson interferometric spectrometer is described. Its intended use is to measure the atmospheric amount of various gases which absorb in the near-infrared, visible, and near-ultraviolet portions of the electromagnetic spectrum. Preliminary spectra which contain the alpha, 0.8 micrometer, and rho sigma tau water vapor absorption bands in the near-infrared are presented to indicate the present capability of the system. Ultimately, the spectrometer can be used to explore the feasible applications of Fourier transform spectroscopy in the ultraviolet where grating spectrometers were used exclusively.

  6. UV-LED Curing Efficiency of Wood Coatings

    Directory of Open Access Journals (Sweden)

    Véronic Landry

    2015-12-01

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

  7. Monitoring and control of UV and UV-TiO{sub 2} disinfections for municipal wastewater reclamation using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chuang-Hung [Department of Architecture, National United University, Miao-Li 360, Taiwan, ROC (China); Yu, Ruey-Fang, E-mail: rfyu@nuu.edu.tw [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China); Cheng, Wen-Po; Liu, Chun-Ru [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer ANN models can effectively control both UV and UV-TiO{sub 2} disinfections for wastewater reuse. Black-Right-Pointing-Pointer Comparing to UV disinfection, UV-TiO{sub 2} disinfection can save 13.2-15.7% of UV dosage and capacity. Black-Right-Pointing-Pointer SS decreases disinfection efficiency when UV doses were <10,000 {mu}W s/cm{sup 2}. - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO{sub 2} can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO{sub 2} disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO{sub 2} disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO{sub 2} disinfections. A novel ANN control strategy is applied to control UV and UV-TiO{sub 2} disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO{sub 2} disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO{sub 2} disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2-15.7%.

  8. A small suberythemal ultraviolet B dose every second week is sufficient to maintain summer vitamin D levels

    DEFF Research Database (Denmark)

    Bogh, Morten Karsten Bentzen; Schmedes, Anne; Philipsen, Peter Alshede

    2012-01-01

    It is known that ultraviolet (UV) B radiation increases serum 25-hydroxyvitamin D(3) [25(OH)D] level. However, there is uncertainty about the relationship between the maintenance of vitamin D status and UVB.......It is known that ultraviolet (UV) B radiation increases serum 25-hydroxyvitamin D(3) [25(OH)D] level. However, there is uncertainty about the relationship between the maintenance of vitamin D status and UVB....

  9. Development of a low cost UV index datalogger and comparison between UV index sensors

    Science.gov (United States)

    Gomes, L. M.; Ventura, L.

    2018-02-01

    Ultraviolet radiation (UVR) is the part of radiation emitted by the Sun, with range between 280 nm and 400 nm, and that reaches the Earth's surface. The UV rays are essential to the human because it stimulates the production of vitamin D but this radiation may be related to several health problems, including skin cancer and ocular diseases like pterygium, photokeratitis, cataract and more. To inform people about UV radiation, it is adopted the Ultraviolet Index (UVI). This UVI consists in a measure of solar UV radiation level, which contributes to cause sunburn on skin, also known as Erythema, and is indicated as an integer number between 1 and 14, associated to categories from low to extreme respectively. The aim of this work was to develop a low cost UVI datalogger capable of measuring three different UVI sensors simultaneously, record their data with timestamp and serve the measures online through a dedicated server, so general public can access their data and see the current UV radiation conditions. We also compared three different UVI sensors (SGlux UV cosine, Skye SKU440 and SiLabs SI1145) between them and with meteorological models during a period of months to verify their compliance. With five months data, we could verify the sensors working characteristics and decide which among them are the most suitable for research purposes.

  10. Pregnancy outcome and ultraviolet radiation; A systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Megaw, Lauren, E-mail: lauren.megaw@ed.ac.uk [School of Women' s and Infants Health, University of Western Australia, 35 Crawley Ave, Crawley, Perth, Western Australia (Australia); Edinburgh Tommy' s Centre for Reproductive Health, Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh (United Kingdom); Clemens, Tom, E-mail: Tom.clemens@ed.ac.uk [School of Geosciences, University of Edinburgh, Drummond St, Edinburgh, Midlothian (United Kingdom); Dibben, Chris, E-mail: Chris.dibben@ed.ac.uk [School of Geosciences, University of Edinburgh, Drummond St, Edinburgh, Midlothian (United Kingdom); Weller, Richard, E-mail: Richard.weller@ed.ac.uk [MRC Centre for Inflammation Research, Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh (United Kingdom); Stock, Sarah, E-mail: Sarah.stock@ed.ac.uk [School of Women' s and Infants Health, University of Western Australia, 35 Crawley Ave, Crawley, Perth, Western Australia (Australia); Edinburgh Tommy' s Centre for Reproductive Health, Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh (United Kingdom)

    2017-05-15

    Background: Season and vitamin D are indirect and direct correlates of ultraviolet (UV) radiation and are associated with pregnancy outcomes. Further to producing vitamin D, UV has positive effects on cardiovascular and immune health that may support a role for UV directly benefitting pregnancy. Objectives: To investigate the effects of UV exposure on pregnancy; specifically fetal growth, preterm birth and hypertensive complications. Methods: We conducted a systematic review of Medline, EMBASE, DoPHER, Global Health, ProQuest Public Health, AustHealth Informit, SCOPUS and Google Scholar to identify 537 citations, 8 of which are included in this review. This review was registered on PROSPERO and a. narrative synthesis is presented following PRISMA guidance. Results: All studies were observational and assessed at high risk of bias. Higher first trimester UV was associated with and improved fetal growth and increased hypertension in pregnancy. Interpretation is limited by study design and quality. Meta-analysis was precluded by the variety of outcomes and methods. Discussion: The low number of studies and risk of bias limit the validity of any conclusions. Environmental health methodological issues are discussed with consideration given to design and analytical improvements to further address this reproductive environmental health question. Conclusions: The evidence for UV having benefits for pregnancy hypertension and fetal growth is limited by the methodological approaches utilized. Future epidemiological efforts should focus on improving the methods of modeling and linking widely available environmental data to reproductive health outcomes. - Highlights: • Biologically plausible pathways support an association between ultraviolet radiation (UV) and pregnancy outcomes. • This study is the first systematic review of prevailing literature on the relationship between UV and singleton pregnancy outcomes. • It focuses on both substantive findings and the

  11. Pregnancy outcome and ultraviolet radiation; A systematic review

    International Nuclear Information System (INIS)

    Megaw, Lauren; Clemens, Tom; Dibben, Chris; Weller, Richard; Stock, Sarah

    2017-01-01

    Background: Season and vitamin D are indirect and direct correlates of ultraviolet (UV) radiation and are associated with pregnancy outcomes. Further to producing vitamin D, UV has positive effects on cardiovascular and immune health that may support a role for UV directly benefitting pregnancy. Objectives: To investigate the effects of UV exposure on pregnancy; specifically fetal growth, preterm birth and hypertensive complications. Methods: We conducted a systematic review of Medline, EMBASE, DoPHER, Global Health, ProQuest Public Health, AustHealth Informit, SCOPUS and Google Scholar to identify 537 citations, 8 of which are included in this review. This review was registered on PROSPERO and a. narrative synthesis is presented following PRISMA guidance. Results: All studies were observational and assessed at high risk of bias. Higher first trimester UV was associated with and improved fetal growth and increased hypertension in pregnancy. Interpretation is limited by study design and quality. Meta-analysis was precluded by the variety of outcomes and methods. Discussion: The low number of studies and risk of bias limit the validity of any conclusions. Environmental health methodological issues are discussed with consideration given to design and analytical improvements to further address this reproductive environmental health question. Conclusions: The evidence for UV having benefits for pregnancy hypertension and fetal growth is limited by the methodological approaches utilized. Future epidemiological efforts should focus on improving the methods of modeling and linking widely available environmental data to reproductive health outcomes. - Highlights: • Biologically plausible pathways support an association between ultraviolet radiation (UV) and pregnancy outcomes. • This study is the first systematic review of prevailing literature on the relationship between UV and singleton pregnancy outcomes. • It focuses on both substantive findings and the

  12. Differential responses of growth and photosynthesis in Cyamopsis tetragonoloba grown under ultraviolet-B and supplemental long-wavelength radiations

    International Nuclear Information System (INIS)

    Lingakumar, K.; Kulandaivelu, G.

    1998-01-01

    Cyamopsis tetragonoloba seedlings were subjected to continuous ultraviolet (UV)B radiation for 18 h and post-irradiated with 'white light' (WL) and UV-A enhanced fluorescent radiations. UV-B treatment alone reduced plant growth, pigment content, and photosynthetic activities. Supplementation of UV-A promoted the overall seedling growth and enhanced the synthesis of chlorophyll and carotenoids with a relatively high photosystem 1 activity. Post UV-B irradiation under WL failed to photoreactivate the LTV-B damage whereas a positive photoregulatory effect of UV-A was noticed in electron transport rates and low temperature fluorescence emission spectra

  13. An inexpensive setup for assessing the impact of ambient solar ultraviolet radiation on seedlings

    International Nuclear Information System (INIS)

    Adamse, P.; Reed, H.E.; Krizek, D.T.; Britz, S.J.; Mirecki, R.M.

    1997-01-01

    Because of reductions in stratospheric ozone levels due to chlorofluoromethanes and other trace gases, there has been growing concern about the impact of possible increases in ultraviolet-B (UV-B) radiation. Until recently, most studies have focused on the effects of enhanced UV-B levels, however, these have inherent technical difficulties. Ultraviolet-B exclusion studies afford the investigator a rapid means of assessing the effects of present levels of solar UV-B radiation. Unlike UV-B enhancement, UV-B exclusion studies use the sun as the source of UV-B radiation and selective filters to transmit or absorb this portion of sunlight. This article describes a simple, inexpensive system that was used over a 3-yr period to determine seedling response of cucumber (Cucumis sativus L.), soybean (Glycine max (L.) Merr.), and New Zealand spinach ((Tetragonia tetragonoides (Pallas) Kuntze) to UV-B exclusion. Plants of all three species grown outdoors under UV-B absorbing polyester showed an increase in leaf enlargement and biomass accumulation in comparison to those grown under UV-B transmitting cellulose acetate filters. The bask materials used consist of plastic window boxes, plastic filters that transmit or absorb in the UV-B region, wire supports, and binder clips. This setup can be used to demonstrate bask principles of photobiology and stress physiology. It is ideal for students interested in conducting short-term science projects on the effects of solar UV radiation

  14. Comparison of stratospheric NO2 profiles above Kiruna, Sweden retrieved from ground-based zenith sky DOAS measurements, SAOZ balloon measurements and SCIAMACHY limb observations

    Science.gov (United States)

    Gu, Myojeong; Enell, Carl-Fredrik; Hendrick, François; Pukite, Janis; Van Roozendael, Michel; Platt, Ulrich; Raffalski, Uwe; Wagner, Thomas

    2015-04-01

    Stratospheric NO2 not only destroys ozone but acts as a buffer against halogen catalyzed ozone loss by converting halogen species into stable nitrates. These two roles of stratospheric NO2 depend on the altitude. Hence, the objective of this study is to investigate the vertical distribution of stratospheric NO2. We compare the NO2 profiles derived from the zenith sky DOAS with those obtained from, SAOZ balloon measurements and satellite limb observations. Vertical profiles of stratospheric NO2 are retrieved from ground-based zenith sky DOAS observations operated at Kiruna, Sweden (68.84°N, 20.41°E) since 1996. To determine the profile of stratospheric NO2 measured from ground-based zenith sky DOAS, we apply the Optimal Estimation Method (OEM) to retrieval of vertical profiles of stratospheric NO2 which has been developed by IASB-BIRA. The basic principle behind this profiling approach is the dependence of the mean scattering height on solar zenith angle (SZA). We compare the retrieved profiles to two additional datasets of stratospheric NO2 profile. The first one is derived from satellite limb observations by SCIAMACHY (Scanning Imaging Absorption spectrometer for Atmospheric CHartographY) on EnviSAT. The second is derived from the SAOZ balloon measurements (using a UV/Visible spectrometer) performed at Kiruna in Sweden.

  15. 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)

  16. Ultraviolet dosimetry using thermoluminescent phosphors - an update

    International Nuclear Information System (INIS)

    Nagpal, J.S.

    1998-04-01

    Intrinsic response of various thermoluminescent (TL) materials such as CaSO 4 (Dy, Eu, Mn, Sm, Tb, or Tm), LiF (Mg, Cu, P), Mg 2 SiO 4 :Tb, CaF 2 :Dy, CaF 2 :Tb, ThO 2 :Tb and Al 2 O 3 (Si, Ti); cathodoluminescent phosphors Y 3 Al 5 O 12 :Ce, Y 3 Al 5 O 12 :Tb and Y(V,P)O 4 :Eu; and fluorescent lamp phosphors calcium halophosphate (Mn,Sb) and Ce Mg aluminate (Eu, Tb) to ultraviolet (UV) radiations has been studied. Intrinsic TL response of most of the phosphors is rate (radiant flux) dependent. For the first time, UV response of the materials is reported for a fixed total radiant energy (total UV dose), at a single radiant flux (260 μW.cm -2 ), for an appropriate comparison. A wide range of UV sensitivity is observed. Studies conducted using UV radiation from two unfiltered low pressure mercury lamps show significant differences in glow curves, as compared to those obtained with nearly monochromatic UV radiations. Photons of wavelength 365 nm induce bleaching of TL induced by 254 nm photons, in most of the materials. Sequential/tandem exposures to 254 nm and 365 nm photons have yielded new but alarming results in CaF 2 :Tb. Preferential induction and bleaching of specific TL glow peaks by 365 nm and 254 nm photons are interesting characteristics discovered in CaSO 4 :Eu. Photoluminescence studies of Tb 3+ and Eu 3+ activated phosphors have augmented the inferences drawn from the bleaching effects produced by 365 nm photons. Earlier work carried out on phototransferred thermoluminescence of CaSO 4 :Dy-teflon dosimeters, TLD-100, Mg 2 SiO 4 :Tb and Al 2 O 3 (Si,Ti) has also been reviewed. (author)

  17. INACTIVATION OF MS2 VIRUS IN DRINKING WATER: ATLANTIC ULTRAVIOLET CORPORATION MEGATRON UNIT, MODEL M250 AT CHULA VISTA, CALIFORNIA

    Science.gov (United States)

    Verification testing of the Atlantic Ultraviolet Megatron M250 system was conducted over a 48-day period from 11/01/01 to 12/18/01. The feedwater to the ultraviolet (UV) unit during the testing was effluent from the Otay Water Treatment Plant (OWTP), a conventional plant with fl...

  18. Ultra-violet radiation: hazard in workplaces? (part II)

    International Nuclear Information System (INIS)

    Mohd Yusof Mohd Ali

    2003-01-01

    Not many workers are aware that apart from chemicals, physical agents, noise and machines which are known to be hazardous in workplaces, there exist another source of hazard which is equally important to be recognised and respected, that is hazard due to ultrviolet radiation (UV). This is the continuation of part I, which was discussed in the later issue. In this part, hazard of ultraviolet radiation were briefly discused i.e. effects on the skin and the eyes. Other subjects discussed are exposure limits, how to assess the radiation, protection against ultraviolet radiation

  19. The influence of UV radiation on protistan evolution

    Science.gov (United States)

    Rothschild, L. J.

    1999-01-01

    Ultraviolet radiation has provided an evolutionary challenge to life on Earth. Recent increases in surficial ultraviolet B fluxes have focused attention on the role of UV radiation in protistan ecology, cancer, and DNA damage. Exploiting this new wealth of data, I examine the possibility that ultraviolet radiation may have played a significant role in the evolution of the first eukaryotes, that is, protists. Protists probably arose well before the formation of a significant ozone shield, and thus were probably subjected to substantial ultraviolet A, ultraviolet B, and ultraviolet C fluxes early in their evolution. Evolution consists of the generation of heritable variations and the subsequent selection of these variants. Ultraviolet radiation has played a role both as a mutagen and as a selective agent. In its role as a mutagen, it may have been crucial in the origin of sex and as a driver of molecular evolution. As a selective agent, its influence has been broad. Discussed in this paper are the influence of ultraviolet radiation on biogeography, photosynthesis, and desiccation resistance.

  20. Solar ultraviolet radiation response of EBT2 Gafchromic, radiochromic film

    International Nuclear Information System (INIS)

    Butson, Ethan T; Yu, Peter K N; Butson, Martin J

    2013-01-01

    Measurement of solar ultraviolet (UV) radiation is an important aspect of dosimetry for the improved knowledge of UV exposure and its associated health related issues. EBT2 Gafchromic film has been designed by its manufacturers as an improved tool for ionizing radiation dosimetry. The film is stated as exhibiting a significant reduction in UV response. However, results have shown that when exposed to UV from the ‘bottom side’ i.e. from the thick laminate side, the film exhibits a sensitivity to solar UV radiation which is both measurable and accurate for UV dosimetry. Films were irradiated in this position to known solar UV exposures and results are quantified showing a reproducibility of measurement to within ±7% (1 SD) when compared to calibrated UV meters. With an exposure of 20 J cm −2 broad spectrum solar UV, the films net OD change was found to be 0.248 OD ± 0.021 OD when analysing the results using the red channel region of an Epson V700 desktop scanner. This was compared to 0.0294 OD ± 0.0053 OD change with exposure to the same UV exposure from the top side. This means that solar UV dosimetry can be performed using EBT2 Gafchromic film utilizing the underside of the film for dosimetry. The main advantages of this film type for measurement of UV exposure is the visible colour change and thus easy analysis using a desktop scanner as well as its uniformity in response and its robust physical strength for use in outside exposure situations. (note)