Sample records for absorb uv radiation

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

    PubMed

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

    2012-12-22

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

  2. Effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme in bean (Phaseolus vulgaris L.) grown under different nitrogen conditions.

    PubMed

    Pinto, M E; Casati, P; Hsu, T P; Ku, M S; Edwards, G E

    1999-02-01

    The effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme have been examined in different cultivars of Phaseolous vulgaris L. grown under 1 and 12 mM nitrogen. Low nitrogen nutrition reduces chlorophyll and soluble protein contents in the leaves and thus the photosynthesis rate and dry-matter accumulation. Chlorophyll, soluble protein and Rubisco contents and photosynthesis rate are not significantly altered by ambient levels of UV-B radiation (17 microW m-2, 290-320 nm, 4 h/day for one week). Comparative studies show that under high nitrogen, UV-B radiation slightly enhances leaf expansion and dry-matter accumulation in cultivar Pinto, but inhibits these parameters in Vilmorin. These results suggest that the UV-B effect on growth is mediated through leaf expansion, which is particularly sensitive to UV-B, and that Pinto is more tolerant than Vilmorin. The effect of UV-B radiation on UV-B-absorbing compounds and on NADP-malic enzyme (NADP-ME) activity is also examined. Both UV-B radiation and low-nitrogen nutrition enhance the content of UV-B-absorbing compounds, and among the three cultivars used, Pinto exhibits the highest increases and Arroz the lowest. The same trend is observed for the specific activity and content of NADP-ME. On a leaf-area basis, the amount of UV-B-absorbing compounds is highly correlated with the enzyme activity (r2 = 0.83), suggesting that NADP-ME plays a key role in biosynthesis of these compounds. Furthermore, the higher sensitivity of Vilmorin than Pinto to UV-B radiation appears to be related to the activity of NADP-ME and the capacity of the plants to accumulate UV-B-absorbing compounds.

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

    PubMed

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

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A < 370 nm; (3) attenuate UV-B and UV-A; (4) attenuate UV-B, UV-A and blue light; and (5) as a control not attenuating these wavebands. Attenuation of blue light significantly reduced the flavonoid content in leaf adaxial epidermis and reduced the whole-leaf concentrations of quercetin derivatives relative to kaempferol derivatives. In contrast, UV-B responses were not significant. These results show that pea plants regulate epidermal UV-A absorbance and accumulation of individual flavonoids by perceiving complex radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors. © 2014 John Wiley & Sons Ltd.

  4. UV-absorbing bacteria in coral mucus and their response to simulated temperature elevations

    NASA Astrophysics Data System (ADS)

    Ravindran, J.; Kannapiran, E.; Manikandan, B.; Francis, K.; Arora, Shruti; Karunya, E.; Kumar, Amit; Singh, S. K.; Jose, Jiya

    2013-12-01

    Reef-building corals encompass various strategies to defend against harmful ultraviolet (UV) radiation. Coral mucus contains UV-absorbing compounds and has rich prokaryotic diversity associated with it. In this study, we isolated and characterized the UV-absorbing bacteria from the mucus of the corals Porites lutea and Acropora hyacinthus during the pre-summer and summer seasons. A total of 17 UV-absorbing bacteria were isolated and sequenced. The UV-absorbing bacteria showed UV absorption at wavelengths ranging from λ max = 333 nm to λ min = 208 nm. Analysis of the DNA sequences revealed that the majority of the UV-absorbing bacteria belonged to the family Firmicutes and the remaining belonged to the family Proteobacteria (class Gammaproteobacteria). Comparison of the sequences with the curated database yielded four distinct bacterial groups belonging to the genus Bacillus, Staphylococcus, Salinicoccus and Vibrio. The absorption peaks for the UV-absorbing bacteria shifted to the UV-A range (320-400 nm) when they were incubated at higher temperatures. Deciphering the complex relationship between corals and their associated bacteria will help us to understand their adaptive strategies to various stresses.

  5. Altered UV absorbance and cytotoxicity of chlorinated sunscreen agents.

    PubMed

    Sherwood, Vaughn F; Kennedy, Steven; Zhang, Hualin; Purser, Gordon H; Sheaff, Robert J

    2012-12-01

    Sunscreens are widely utilized due to the adverse effects of ultraviolet (UV) radiation on human health. The safety of their active ingredients as well as that of any modified versions generated during use is thus of concern. Chlorine is used as a chemical disinfectant in swimming pools. Its reactivity suggests sunscreen components might be chlorinated, altering their absorptive and/or cytotoxic properties. To test this hypothesis, the UV-filters oxybenzone, dioxybenzone, and sulisobenzone were reacted with chlorinating agents and their UV spectra analyzed. In all cases, a decrease in UV absorbance was observed. Given that chlorinated compounds can be cytotoxic, the effect of modified UV-filters on cell viability was examined. Chlorinated oxybenzone and dioxybenzone caused significantly more cell death than unchlorinated controls. In contrast, chlorination of sulisobenzone actually reduced cytotoxicity of the parent compound. Exposing a commercially available sunscreen product to chlorine also resulted in decreased UV absorbance, loss of UV protection, and enhanced cytotoxicity. These observations show chlorination of sunscreen active ingredients can dramatically decrease UV absorption and generate derivatives with altered biological properties.

  6. The Nature of the UV/X-ray Absorber In PG 2302+029

    NASA Technical Reports Server (NTRS)

    Sabra, Bassem M.; Hamann, Fred; Jannuzi, Buell T.; George, Ian M.; Shields, Joseph C.

    2003-01-01

    We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029. This quasar has a rare system of ultra-high velocity (-56,000 km s(exp -1) UV absorption lines that form in an outflow from the active nucleus. The Chandra data indicate that soft X-ray absorption is also present. We perform a joint UV and X-ray analysis, using photoionization calculations, to determine the nature of the absorbing gas. The UV and X-ray datasets were not obtained simultaneously. Nonetheless, our analysis suggests that the X-ray absorption occurs at high velocities in the same general region as the UV absorber. There are not enough constraints to rule out multi-zone models. In fact, the distinct broad and narrow UV line profiles clearly indicate that multiple zones are present. Our preferred estimates of the ionization and total column density in the X-ray absorber (logU = 1.6, N(sub eta) = 10(exp 22.4) cm (exp -2) over predict the O VI lambda lambda1032,1038 absorption unless the X-ray absorber is also outflowing at approximately 56,000 km s(exp-l), but they over predict the Ne VIII lambda lambda 770,780 absorption at all velocities. If we assume that the X-ray absorbing gas is outflowing at the same velocity of the UV-absorbing wind and that the wind is radiatively accelerated, then the outflow must be launched at a radius of less than or equal to 10(exp 15) cm from the central continuum source. The smallness of this radius casts doubts on the assumption of radiative acceleration.

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

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

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

    PubMed

    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 < 0.05), but proline content significantly increased (p < 0.05), when exposed to either enhanced UV-B or water deficit. The negative effects of enhanced UV-B were alleviated when water deficit was applied. There were increases in UV-absorbing compounds and osmotic adjustment substances when exposed to a combination of enhanced UV-B and water deficit compared with single stresses, except for the proline content in D. vinealis. In addition, our results also indicated interspecific differences in response to enhanced UV-B, water deficit, and their combination. Compared with B. 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.

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

    PubMed Central

    Nikafshar, Saeid; Zabihi, Omid; Ahmadi, Mojtaba; Mirmohseni, Abdolreza; Taseidifar, Mojtaba; Naebe, Minoo

    2017-01-01

    Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV) damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR) analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM) imaging. Additionally, the glass transition temperatures (Tg) before and during UV radiation were measured. After an 800 h UV radiation, mechanical test results revealed that the lack of the UV absorber can lead to a ~30% reduction in tensile strength. However, in the presence of Tinuvin 1130, the tensile strength was reduced only by ~11%. It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light. PMID:28772538

  10. Analysis of UV-absorbing photoprotectant mycosporine-like amino acid (MAA) in the cyanobacterium Arthrospira sp. CU2556.

    PubMed

    Rastogi, Rajesh P; Incharoensakdi, Aran

    2014-07-01

    Mycosporine-like amino acids (MAAs) are ecologically important biomolecules with great photoprotective potential. The present study aimed to investigate the biosynthesis of MAAs in the cyanobacterium Arthrospira sp. CU2556. High-performance liquid chromatography (HPLC) with photodiode-array detection studies revealed the presence of a UV-absorbing compound with an absorption maximum at 310 nm. Based on its UV absorption spectrum and ion trap liquid chromatography/mass spectrometry (LC/MS) analysis, the compound was identified as a primary MAA mycosporine-glycine (m/z: 246). To the best of our knowledge this is the first report on the occurrence of MAA mycosporine-glycine (M-Gly) in Arthrospira strains studied so far. In contrast to photosynthetic activity under UV-A radiation, the induction of the biosynthesis of M-Gly was significantly more prominent under UV-B radiation. The content of M-Gly was found to increase with the increase in exposure time under UV-B radiation. The MAA M-Gly was highly stable under UV radiation, heat, strongly acidic and alkaline conditions. It also exhibited good antioxidant activity and photoprotective ability by detoxifying the in vivo reactive oxygen species (ROS) generated by UV radiation. Our results indicate that the studied cyanobacterium may protect itself by synthesizing the UV-absorbing/screening compounds as important defense mechanisms, in their natural brightly-lit habitat with high solar UV-B fluxes.

  11. Acute dermal toxicity and sensitization studies of novel nano-enhanced UV absorbers.

    PubMed

    Piasecka-Zelga, Joanna; Zelga, Piotr; Górnicz, Magdalena; Strzelczyk, Paweł; Sójka-Ledakowicz, Jadwiga

    2015-01-01

    Many employees working outside are exposed to the harmful effects of UV radiation. A growing problem is also sensitization to textile materials and allergic reactions to active compounds. Groups of inorganic UV blockers with nanoparticles may provide superior properties over organic UV absorbers with relatively less potential of provoking dermatitis. To assess acute dermal irritation and sensitization of nano UV absorbers. Five UV absorbers with nano-sized particles (Z11, TiO2 - SiO2 [TDPK], TK44, TK11, A8G) and 2 vehicles (paste-based on 10% PEG, and dispersion with 1% HEC) were tested. Acute dermal irritation was tested using group of 3 rabbits for each absorber. The sensitization study was carried out on groups of 15 guinea pigs for each tested textile with a UV absorber showing an Ultraviolet Protection Factor (UPF)>40. This research was designed according to OECD Test Guideline No. 404 and 406, and 21 rabbits and 60 guinea pigs were used in the study. In acute dermal irritation, Z11 and A8G modifiers and the analyzed paste gave results of 0.047 to 0.33 which classifies them as barely perceptible irritants, whereas the other analyzed modifiers and dispersion gave results of 0.00 and were classified as nonirritating. Only the textile with TK 11 did not have UPF>40. The analyzed barrier materials were classified as nonsenitizers (TDPK, A8G) or mild sensitizers (TK44, Z11). None of the analyzed materials or modifiers induced major skin reactions in animals. Therefore, they present low risk of provoking skin reactions in humans.

  12. Venus Upper Clouds and the UV Absorber From MESSENGER/MASCS Observations

    NASA Astrophysics Data System (ADS)

    Pérez-Hoyos, S.; Sánchez-Lavega, A.; García-Muñoz, A.; Irwin, P. G. J.; Peralta, J.; Holsclaw, G.; McClintock, W. M.; Sanz-Requena, J. F.

    2018-01-01

    One of the most intriguing, long-standing questions regarding Venus's atmosphere is the origin and distribution of the unknown UV absorber, responsible for the absorption band detected at the near-UV and blue range of Venus's spectrum. In this work, we use data collected by Mercury Atmospheric and Surface Composition Spectrometer (MASCS) spectrograph on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission during its second Venus flyby in June 2007 to address this issue. Spectra range from 0.3 μm to 1.5 μm including some gaseous H2O and CO2 bands, as well as part of the SO2 absorption band and the core of the UV absorption. We used the NEMESIS radiative transfer code and retrieval suite to investigate the vertical distribution of particles in the equatorial atmosphere and to retrieve the imaginary refractive indices of the UV absorber, assumed to be well mixed with Venus's small mode 1 particles. The results show a homogeneous equatorial atmosphere, with cloud tops (height for unity optical depth) at 75 ± 2 km above surface. The UV absorption is found to be centered at 0.34 ± 0.03 μm with a full width at half maximum of 0.14 ± 0.01 μm. Our values are compared with previous candidates for the UV aerosol absorber, among which disulfur oxide (S2O) and dioxide disulfur (S2O2) provide the best agreement with our results.

  13. Triplet-triplet energy transfer from a UV-A absorber butylmethoxydibenzoylmethane to UV-B absorbers.

    PubMed

    Kikuchi, Azusa; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Yagi, Mikio

    2014-01-01

    The phosphorescence decay of a UV-A absorber, 4-tert-butyl-4'-methoxydibenzolymethane (BMDBM) has been observed following a 355 nm laser excitation in the absence and presence of UV-B absorbers, 2-ethylhexyl 4-methoxycinnamate (octyl methoxycinnamate, OMC) and octocrylene (OCR) in ethanol at 77 K. The lifetime of the lowest excited triplet (T1) state of BMDBM is significantly reduced in the presence of OMC and OCR. The observed quenching of BMDBM triplet by OMC and OCR suggests that the intermolecular triplet-triplet energy transfer occurs from BMDBM to OMC and OCR. The T1 state of OCR is nonphosphorescent or very weakly phosphorescent. However, we have shown that the energy level of the T1 state of OCR is lower than that of the enol form of BMDBM. Our methodology of energy-donor phosphorescence decay measurements can be applied to the study of the triplet-triplet energy transfer between UV absorbers even if the energy acceptor is nonphosphorescent. In addition, the delayed fluorescence of BMDBM due to triplet-triplet annihilation was observed in the BMDBM-OMC and BMDBM-OCR mixtures in ethanol at 77 K. Delayed fluorescence is one of the deactivation processes of the excited states of BMDBM under our experimental conditions. © 2013 The American Society of Photobiology.

  14. Construction of Nontoxic Polymeric UV-Absorber with Great Resistance to UV-Photoaging

    PubMed Central

    Huang, Zhong; Ding, Aishun; Guo, Hao; Lu, Guolin; Huang, Xiaoyu

    2016-01-01

    In this article, we developed a series of new nontoxic polymeric UV-absorbers through covalently attaching a benzophenone derivative onto the main chain of poly(vinyl chloride) (PVC) via mild and quantitative click chemistry. Azide groups were firstly introduced into the backbone of PVC via a nucleophilic reaction without affecting polymeric skeleton. Copper-catalyzed Husigen-Click cycloaddition reaction was performed between the pendant azide groups of PVC and alkynyl of (2-hydroxy-4-(prop-2-ynyloxy)phenyl)(phenyl)methanone at ambient temperature for affording the desired PVC-based UV-absorbers (PVC-UV) with different amounts of benzophenone moieties, which displayed great resistance to photoaging without degradation while exposed to UV irradiation. These polymeric UV-absorbers also showed good solubilities in common organic solvents and no cytotoxicity vs. HaCat cell. Small amounts of PVC-UV were homogeneously mixed with PVC as additive for stabilizing PVC against UV-photoaging without degradation and releasing small molecule even after 200 h while keeping thermal stability. This route of polymeric additive clearly paved an efficient way for solving the puzzle of separation of small molecule additive. PMID:27138547

  15. Model of radiation transmittance by inorganic fouling on UV reactor lamp sleeves.

    PubMed

    Wait, Isaac W; Blatchley, Ernest R

    2010-11-01

    The efficacy of UV disinfection of water depends on the ability of radiation to pass from UV lamps through the quartz sleeves that encase them; the accumulation of metal-containing foulants on sleeve surfaces inhibits disinfection by absorbing radiation that would otherwise be available for inactivation. In a series of experiments, the composition and quantity of sleeve foulants were studied relative to water chemistry and sleeve transmittance. Findings indicate that iron and calcium dominate fouling, with elevated fouling activity by iron, aluminum, manganese, and zinc. A regression-based modeling approach was used to characterize and quantify the effects of foulant metals on UV absorbance. The molar extinction coefficient for iron was found to be more than 3 times greater than that of calcium. Iron's relatively high activity in fouling reactions, elevated capacity to absorb UV, and reduced solubility under oxidizing conditions makes it a fouling precursor of particular concern, with respect to potential for sleeve fouling in UV reactors.

  16. Photoprotectant improves photostability and bioactivity of abscisic acid under UV radiation.

    PubMed

    Gao, Fei; Hu, Tanglu; Tan, Weiming; Yu, Chunxin; Li, Zhaohu; Zhang, Lizhen; Duan, Liusheng

    2016-05-01

    Photosensitivity causes serious drawback for abscisic acid (ABA) application, but preferable methods to stabilize the compound were not found yet. To select an efficient photoprotectant for the improvement of photostability and bioactivity of ABA when exposed to UV light, we tested the effects of a photostabilizer bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (HS-770) and two UV absorbers 2-hydroxy-4-n-octoxy-benzophenone (UV-531) and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP-4) with or without HS-770 on the photodegradation of ABA. Water soluble UV absorber BP-4 and oil soluble UV absorber UV-531 showed significant photo-stabilizing capability on ABA, possibly due to competitive energy absorption of UVB by the UV absorbers. The two absorbers showed no significant difference. Photostabilizer HS-770 accelerated the photodegradation of ABA and did not improve the photo-stabilizing capability of BP-4, likely due to no absorption in UVB region and salt formation with ABA and BP-4. Approximately 26% more ABA was kept when 280mg/l ABA aqueous solution was irradiated by UV light for 2h in the presence of 200mg/l BP-4. What's more, its left bioactivity on wheat seed (JIMAI 22) germination was greatly kept by BP-4, comparing to that of ABA alone. The 300 times diluent of 280mg/l ABA plus 200mg/l BP-4 after 2h irradiation showed more than 13% inhibition on shoot and root growth of wheat seed than that of ABA diluent alone. We concluded that water soluble UV absorber BP-4 was an efficient agent to keep ABA activity under UV radiation. The results could be used to produce photostable products of ABA compound or other water soluble agrichemicals which are sensitive to UV radiation. The frequencies and amounts of the agrichemicals application could be thereafter reduced. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    PubMed

    Soriano-Melgar, Lluvia de Abril Alexandra; Alcaraz-Meléndez, Lilia; Méndez-Rodríguez, Lía C; Puente, María Esther; Rivera-Cabrera, Fernando; Zenteno-Savín, Tania

    2014-05-01

    Ultraviolet type C (UV-C) radiation has higher energy than the UV-B radiation and has been less studied because it is completely absorbed by the ozone layer. However, artificial UV-C radiation can generate diverse modifications in the plants. Given that exposure to UV-C for short periods of time increases the antioxidant content, improving the appearance and shelf-life of products, its potential application in postharvest treatments to modify the antioxidant content of medicinal plants, such as damiana (Turnera diffusa), is novel and relevant. To determine the effects of UV-C radiation on enzymatic and non-enzymatic antioxidant defenses, as well as oxidative damage levels, in damiana (Turnera diffusa) plants in vitro. UV-C radiation decreased superoxide dismutase (SOD, EC 1.15.1.1) and total peroxidases (POX, EC 1.11.1) activities, the concentration of chlorophylls (a and b), carotenes, vitamin C, and total antioxidant capacity. UV-C radiation increased the phenolic compound levels in damiana. Loss of antioxidant defenses was higher in damiana plants exposed to higher UV-C doses and/or for longer periods. This study suggests that UV-C radiation induces oxidative stress, evidenced as increased protein carbonyls and phenolic compound content, in damiana (T. diffusa). Low dose, short exposure to UV-C stimulates phenolic compound content in damiana. Thus, controlled UV-C treatments could be used as postharvest treatment to increase phenolic compound content in damiana plants. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  18. Responses of a marine red tide alga Skeletonema costatum (Bacillariophyceae) to long-term UV radiation exposures.

    PubMed

    Wu, Hongyan; Gao, Kunshan; Wu, Haiyan

    2009-02-09

    UV radiation (280-400 nm) is known to affect phytoplankton in negative, neutral and positive ways depending on the species or levels of irradiation energy. However, little has been documented on how photosynthetic physiology and growth of red tide alga respond to UVR in a long-term period. We exposed the cells of the marine red tide diatom Skeletonema costatum for 6 days to simulated solar radiations with UV-A (320-400 nm) or UV-A+UV-B (295-400 nm) and examined their changes in photosynthesis and growth. Presence of UV-B continuously reduced the effective photosynthetic quantum yield of PSII, and resulted in complete growth inhibition and death of cells. When UV-B or UV-B+UV-A was screened off, the growth rate decreased initially but regained thereafter. UV-absorbing compounds and carotenoids increased in response to the exposures with UVR. However, mechanisms for photoprotection associated with the increased carotenoids or UV-absorbing compounds were not adequate under the continuous exposure to a constant level of UV-B (0.09 Wm(-2), DNA-weighted). In contrast, under solar radiation screened off UV-B, the photoprotection was first accomplished by an initial increase of carotenoids and a later increase in UV-absorbing compounds. The overall response of this red tide alga to prolonged UV exposures indicates that S. costatum is a UV-B-sensitive species and increased UV-B irradiance would influence the formation of its blooms.

  19. Effect of UV-C radiation and vapor released from a water hyacinth root absorbent containing bergamot oil to control mold on storage of brown rice.

    PubMed

    Songsamoe, Sumethee; Matan, Narumol; Matan, Nirundorn

    2016-03-01

    The aims of this study were to develop absorbent material from a water hyacinth root containing bergamot oil and to improve its antifungal activity by using ultraviolet C (UV-C) against the growth of A. flavus on the brown rice. Process optimization was studied by the immersion of a water hyacinth root into a water and bergamot oil (300, 500 and 700 μl ml(-1)). The root (absorbent material) was dried at 50, 70, and 90 °C for 10 min. Then, ultraviolet C (UV-C) was used for enhancing the antifungal activity of bergamot oil for 10, 15, and 20 min. The shelf-life of the brown rice with the absorbent after incubation at 25 ° C with 100 % RH for 12 weeks was also investigated. A microscope and a Fourier transform infrared spectroscopy (FTIR) were used to find out possible mode of action. Results indicated that the absorbent material produced from the water hyacinth root containing bergamot oil at 500 μl ml(-1) in the water solution, dried at 70 ° C and UV for 15 min showed the highest antifungal activity in a vapor phase against A. flavus on the brown rice. A microscopy investigation confirmed that the water hyacinth root could absorb bergamot oil from an outside water solution into root cells. Limonene in vapor phase was shown to be a stronger inhibitor than essential oil after UV-C radiation and should be the key factor in boosting bergamot oil antifungal activity. A vapor phase of bergamot oil could be released and inhibit natural mold on the surface of the brown rice for up to 12 weeks; without the absorbent, mold covered the brown rice in only 4 weeks.

  20. UV absorbers for cellulosic apparels: A computational and experimental study

    NASA Astrophysics Data System (ADS)

    Sahar, Anum; Ali, Shaukat; Hussain, Tanveer; Irfan, Muhammad; Eliasson, Bertil; Iqbal, Javed

    2018-01-01

    Two triazine based Ultra Violet (UV) absorbers Sulfuric acid mono-(2-{4-[4-chloro-6-(4-{4-chloro-6-[4-(2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5] triazin-2-ylamino-phenylamino)-[1,3,5]triazin-2-ylamino]-benzenesulfonyl}-ethyl) ester (1a) and 4-{4-chloro-6-[4-(2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5] triazin-2-ylamino}-2-[4-chloro-6-(2-sulfooxy-ethanesulfonyl)-[1,3,5]triazin-2-ylamino]-benzenesulfonic acid (2a) with different substituents were designed computationally. The influence of different substituents on the electrochemical properties and UV spectra of the absorbers was investigated. The presence of electron deficient unit in 1a to the molecular core significantly reduces the LUMO levels and energy gap. The designed absorbers were synthesized via condensation reaction and characterized by UV-Vis, FT-IR, MS studies. The performance of synthesized compounds as UV absorbers and their fastness properties were assessed by finishing the cotton fabric through exhaust method at different concentration and results appeared in good range.

  1. Ultraviolet absorbing compounds provide a rapid response mechanism for UV protection in some reef fish.

    PubMed

    Braun, C; Reef, R; Siebeck, U E

    2016-07-01

    The external mucus surface of reef fish contains ultraviolet absorbing compounds (UVAC), most prominently Mycosporine-like Amino Acids (MAAs). MAAs in the external mucus of reef fish are thought to act as sunscreens by preventing the damaging effects of ultraviolet radiation (UVR), however, direct evidence for their protective role has been missing. We tested the protective function of UVAC's by exposing fish with naturally low, Pomacentrus amboinensis, and high, Thalassoma lunare, mucus absorption properties to a high dose of UVR (UVB: 13.4W∗m(-2), UVA: 6.1W∗m(-2)) and measuring the resulting DNA damage in the form of cyclobutane pyrimidine dimers (CPDs). For both species, the amount of UV induced DNA damage sustained following the exposure to a 1h pulse of high UVR was negatively correlated with mucus absorbance, a proxy for MAA concentration. Furthermore, a rapid and significant increase in UVAC concentration was observed in P. amboinensis following UV exposure, directly after capture and after ten days in captivity. No such increase was observed in T. lunare, which maintained relatively high levels of UV absorbance at all times. P. amboinensis, in contrast to T. lunare, uses UV communication and thus must maintain UV transparent mucus to be able to display its UV patterns. The ability to rapidly alter the transparency of mucus could be an important adaptation in the trade off between protection from harmful UVR and UV communication. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. A Ten-Year Global Record of Absorbing Aerosols Above Clouds from OMI's Near-UV Observations

    NASA Technical Reports Server (NTRS)

    Jethva, Hiren; Torres, Omar; Ahn, Changwoo

    2016-01-01

    Aerosol-cloud interaction continues to be one of the leading uncertain components of climate models, primarily due to the lack of an adequate knowledge of the complex microphysical and radiative processes associated with the aerosol-cloud system. The situations when aerosols and clouds are found in the same atmospheric column, for instance, when light-absorbing aerosols such as biomass burning generated carbonaceous particles or wind-blown dust overlay low-level cloud decks, are commonly found over several regional of the world. Contrary to the cloud-free scenario over dark surface, for which aerosols are known to produce a net cooling effect (negative radiative forcing) on climate, the overlapping situation of absorbing aerosols over cloud can potentially exert a significant level of atmospheric absorption and produces a positive radiative forcing at top-of-atmosphere. The magnitude of direct radiative effects of aerosols above cloud depends directly on the aerosol loading, microphysical-optical properties of the aerosol layer and the underlying cloud deck, and geometric cloud fraction. We help in addressing this problem by introducing a novel product of optical depth of absorbing aerosols above clouds retrieved from near-UV observations made by the Ozone Monitoring Instrument (OMI) on board NASA's Aura platform. The presence of absorbing aerosols above cloud reduces the upwelling radiation reflected by cloud and produces a strong 'color ratio' effect in the near-UV region, which can be unambiguously detected in the OMI measurements. Physically based on this effect, the OMACA algorithm retrieves the optical depths of aerosols and clouds simultaneously under a prescribed state of atmosphere. The algorithm architecture and results from a ten-year global record including global climatology of frequency of occurrence and above-cloud aerosol optical depth, and a discussion on related future field campaigns are presented.

  3. Design of UV-absorbing PVDF membrane via surface-initiated AGET ATRP

    NASA Astrophysics Data System (ADS)

    Dong, Li; Liu, Xiangdong; Xiong, Zhengrong; Sheng, Dekun; Zhou, Yan; Lin, Changhong; Yang, Yuming

    2018-03-01

    Herein, PVDF membranes with excellent UV-absorbing property were first synthesized through grafting the polymerizable low-molecular-weight organic UV-absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA) onto α-bromoester-functionalized PVDF membranes via the surface-initiated activator generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The surface initiators were immobilized by the reaction between 2-bromoisobutyryl bromide (BIBB) and the hydroxylated PVDF membranes. PVDF-g-PBPMA membranes with different grafting densities were obtained by tuning the polymerization time and the modified membranes were characterized by 1H-NMR, FT-IR, XPS, SEM, UV-vis Spectrophotometer, TGA and DSC. The experimental results indicated that PBPMA chains were successfully introduced onto PVDF membranes. Most importantly, the PVDF-g-PBPMA membranes exhibited outstanding UV-shielding property. UV-vis transmittance spectra showed that most UV light below 360 nm could be absorbed by PVDF-g-PBPMA membranes and the whole UV light region (200-400 nm) can be blocked with the reaction time increased.

  4. Adverse Effects of UV-B Radiation on Plants Growing at Schirmacher Oasis, East Antarctica.

    PubMed

    Singh, Jaswant; Singh, Rudra P

    2014-01-01

    This study aimed to assess the impacts of ultraviolet-B (UV-B) radiation over a 28-day period on the levels of pigments of Umbilicaria aprina and Bryum argenteum growing in field. The depletion of stratospheric ozone is most prominent over Antarctica, which receives more UV-B radiation than most other parts of the planet. Although UV-B radiation adversely affects all flora, Antarctic plants are better equipped to survive the damaging effects of UV-B owing to defenses provided by UV-B absorbing compounds and other screening pigments. The UV-B radiations and daily average ozone values were measured by sun photometer and the photosynthetic pigments were analyzed by the standard spectrophotometric methods of exposed and unexposed selected plants. The daily average atmospheric ozone values were recorded from 5 January to 2 February 2008. The maximum daily average for ozone (310.7 Dobson Units (DU)) was recorded on 10 January 2008. On that day, average UV-B spectral irradiances were 0.016, 0.071, and 0.186 W m(-2) at wavelengths of 305, 312, and 320 nm, respectively. The minimum daily average ozone value (278.6 DU) was recorded on 31 January 2008. On that day, average UV-B spectral irradiances were 0.018, 0.085, and 0.210 W m(-2) at wavelengths of 305, 312, and 320 nm, respectively. Our results concludes that following prolonged UV-B exposure, total chlorophyll levels decreased gradually in both species, whereas levels of UV-B absorbing compounds, phenolics, and carotenoids gradually increased.

  5. Adverse Effects of UV-B Radiation on Plants Growing at Schirmacher Oasis, East Antarctica

    PubMed Central

    Singh, Jaswant; Singh, Rudra P.

    2014-01-01

    This study aimed to assess the impacts of ultraviolet-B (UV-B) radiation over a 28-day period on the levels of pigments of Umbilicaria aprina and Bryum argenteum growing in field. The depletion of stratospheric ozone is most prominent over Antarctica, which receives more UV-B radiation than most other parts of the planet. Although UV-B radiation adversely affects all flora, Antarctic plants are better equipped to survive the damaging effects of UV-B owing to defenses provided by UV-B absorbing compounds and other screening pigments. The UV-B radiations and daily average ozone values were measured by sun photometer and the photosynthetic pigments were analyzed by the standard spectrophotometric methods of exposed and unexposed selected plants. The daily average atmospheric ozone values were recorded from 5 January to 2 February 2008. The maximum daily average for ozone (310.7 Dobson Units (DU)) was recorded on 10 January 2008. On that day, average UV-B spectral irradiances were 0.016, 0.071, and 0.186 W m-2 at wavelengths of 305, 312, and 320 nm, respectively. The minimum daily average ozone value (278.6 DU) was recorded on 31 January 2008. On that day, average UV-B spectral irradiances were 0.018, 0.085, and 0.210 W m-2 at wavelengths of 305, 312, and 320 nm, respectively. Our results concludes that following prolonged UV-B exposure, total chlorophyll levels decreased gradually in both species, whereas levels of UV-B absorbing compounds, phenolics, and carotenoids gradually increased. PMID:24748743

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

    PubMed

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

    2017-02-01

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

  7. In vitro photostability and photoprotection studies of a novel 'multi-active' UV-absorber.

    PubMed

    Venditti, E; Spadoni, T; Tiano, L; Astolfi, P; Greci, L; Littarru, G P; Damiani, E

    2008-08-01

    This paper reports on the synthesis and properties of a new UV-absorber (OC-NO) based on the most popular UV filter worldwide, ethylhexyl methoxycinnamate (OMC) in which the methoxy group has been replaced with a pyrrolidine nitroxide bearing antioxidant activity. This sunscreen active has therefore both UV-absorbing and antioxidant properties which could ideally address both the UV-B and UV-A skin photo-damage. For broad-spectrum coverage, the combinations of OC-NO with two commonly used UV-A absorbers (BMDBM and DHHB) were also studied. The results obtained reveal that OC-NO: (a) is as photostable as OMC after UV-A exposure; (b) acts as free radical scavenger as demonstrated by EPR and chemical studies; (c) reduces UV-A and UV-A+BMDBM induced lipid peroxidation in liposomes and cells, measured as reduced TBARS levels and increased C11-BODIPY red fluorescence, respectively; (d) has comparable antioxidant activity to that of vitamin E and BHT commonly used in skin care formulations; (e) is non-cytotoxic to human skin fibroblasts as assessed with the MTT assay when exposed to increasing doses of UV-A; and (f) OC-NO+DHHB is a promising, photostable broad spectrum UV-filter combination that concomitantly reduces UV-induced free radical damage. These results suggest that nitroxide/antioxidant-based UV-absorbers may pave the way for the utilization of 'multi-active' ingredients in sunscreens thereby reducing the number of ingredients in these formulations.

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

    PubMed

    Herzog, Bernd; Hüglin, Dietmar; Luther, Helmut

    2017-02-01

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

  9. Analysis of reflectance spectra of UV-absorbing aerosol scenes measured by SCIAMACHY

    NASA Astrophysics Data System (ADS)

    de Graaf, M.; Stammes, P.; Aben, E. A. A.

    2007-01-01

    Reflectance spectra from 280-1750 nm of typical desert dust aerosol (DDA) and biomass burning aerosol (BBA) scenes over oceans are presented, measured by the space-borne spectrometer Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). DDA and BBA are both UV-absorbing aerosols, but their effect on the top-of-atmosphere (TOA) reflectance is different due to differences in the way mineral aerosols and smoke reflect and absorb radiation. Mineral aerosols are typically large, inert particles, found in warm, dry continental air. Smoke particles, on the other hand, are usually small particles, although often clustered, chemically very active and highly variable in composition. Moreover, BBA are hygroscopic and over oceans BBA were invariably found in cloudy scenes. TOA reflectance spectra of typical DDA and BBA scenes were analyzed, using radiative transfer simulations, and compared. The DDA spectrum was successfully simulated using a layer with a bimodal size distribution of mineral aerosols in a clear sky. The spectrum of the BBA scene, however, was determined by the interaction between cloud droplets and smoke particles, as is shown by simulations with a model of separate aerosol and cloud layers and models with internally and externally mixed aerosol/cloud layers. The occurrence of clouds in smoke scenes when sufficient water vapor is present usually prevents the detection of optical properties of these aerosol plumes using space-borne sensors. However, the Absorbing Aerosol Index (AAI), a UV color index, is not sensitive to scattering aerosols and clouds and can be used to detect these otherwise obscured aerosol plumes over clouds. The amount of absorption of radiation can be expressed using the absorption optical thickness. The absorption optical thickness in the DDA case was 0.42 (340 nm) and 0.14 (550 nm) for an aerosol layer of optical thickness 1.74 (550 nm). In the BBA case the absorption optical thickness was 0.18 (340 nm) and 0

  10. Absorber for terahertz radiation management

    DOEpatents

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

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

    PubMed

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

    2017-02-01

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

  12. A Global, Decadal, Quantitative Record of Absorbing Aerosols above Cloud Using OMI's Near-UV Observations

    NASA Astrophysics Data System (ADS)

    Torres, O.; Jethva, H. T.; Ahn, C.

    2016-12-01

    Aerosol-cloud interaction continues to be one of the leading uncertain components of climate models, primarily due to the lack of an adequate knowledge of the complex microphysical and radiative processes of the aerosol-cloud system. The situations when aerosols and clouds are found in the same atmospheric column, for instance, when light-absorbing aerosols such as biomass burning generated carbonaceous particles or wind-blown dust overlay low-level cloud decks, are commonly found over several regions of the world. Contrary to the known cooling effects of these aerosols in cloud-free scenario over dark surface, the overlapping situation of absorbing aerosols over cloud can potentially exert a significant level of atmospheric absorption and produces a positive radiative forcing (warming) at top-of-atmosphere. The magnitude of direct radiative effects of aerosols above cloud directly depends on the aerosol loading, microphysical and optical properties of the aerosol layer and the underlying cloud deck, and geometric cloud fraction. We help in addressing this problem by introducing a novel product of above-cloud aerosol optical depth (ACAOD) of absorbing aerosols retrieved from near-UV observations made by the Ozone Monitoring Instrument (OMI) on board NASA's Aura platform. Physically based on the strong `color ratio' effect in the near-UV caused by the spectral absorption of aerosols above cloud, the algorithm, formally named as OMACA, retrieves the optical depths of aerosols and clouds simultaneously under a prescribed state of atmosphere. Here, we present the algorithm architecture and results from an 11-year global record (2005-2015) including global climatology of frequency of occurrence and ACAOD. The theoretical uncertainty analysis and planned validation activities using measurements from upcoming field campaigns are also discussed.

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

    NASA Astrophysics Data System (ADS)

    Horneck, G.

    2007-08-01

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

  14. Kinetic study on UV-absorber photodegradation under different conditions

    NASA Astrophysics Data System (ADS)

    Bubev, Emil; Georgiev, Anton; Machkova, Maria

    2016-09-01

    The photodegradation kinetics of two benzophenone derivative UV-absorbers (UVAs)-BP-4 (benzophenone-4) and 4-HBP (4-hydroxybenzophenone), as additives in polyvinyl acetate (PVAc) films, were studied. Solution-processed PVAc films were irradiated in different environments in order to study oxygen and atmospheric humidity influence on UVA photodegradation. Photodegradation was traced by absorption intensity loss via UV-vis spectroscopy. Both UVAs exhibited excellent photostability in an inert atmosphere. Rate constants showed that BP-4 has better permanence in absence of oxygen. Both film types experienced rapid absorption loss, when irradiated in an oxygen containing atmosphere. UVA degradation was treated as a two-stage process. The photodegradation kinetics in the first stage agreed with the adopted complex rate law, but the second stage was best described by pseudo-first order kinetics. BP-4 exhibited better stability. Oxygen was established as the main accelerating factor for photodegradation of benzophenone derivatives UV-absorbers in thin PVAc films.

  15. The influence of enhanced UV-B radiation on Batrachium trichophyllum and Potamogeton alpinus -- aquatic macrophytes with amphibious character.

    PubMed

    Germ, Mateja; Mazej, Zdenka; Gaberscik, Alenka; Häder, Donat P

    2002-02-01

    The responses of two amphibious species, Batrachium trichophyllum and Potamogeton alpinus to different UV-B environments were studied. Plant material from natural environments, as well as from outdoor treatments was examined. In long-term outdoor experiments plants were grown under three different levels of UV-B radiation: reduced and ambient UV-B levels, and a UV-B level simulating 17% ozone depletion. The following parameters were monitored: contents of total methanol soluble UV-absorbing compounds and chlorophyll a, terminal electron transport system (ETS) activity and optimal and effective quantum yield of photosystem II. No effect of the different UV-B levels on the measured parameters was observed. The amount of UV-B absorbing compounds seems to be saturated, since no differences were observed between treatments and no increase was found in peak season, when natural UV-B levels were the highest. Physiological measurements revealed no harmful effects; neither on potential and actual photochemical efficiency, nor on terminal ETS activity. The contents of UV-B absorbing compounds were examined also in plant material sampled in low and high altitude environments during the growth season. Both species exhibited no seasonal dynamics of production of UV-absorbing compounds. The contents were variable and showed no significant differences between high and low altitude populations.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    because there is anecdotal evidence of plant damage on the saguaros that has been linked to increased UV radiation, and (3) the forests of Nothofagus spp. and the steppe of Patagonia where the risk of plant damage at 35S is 5% and increases to as much as 15% at 55S due to increased UV-B radiation. Measurements of UV-B radiation impinging on the surface at 55S largely exceed the predicted UV-B radiation values at 50 latitude and 0% ozone depletion. Preliminary HPLC analyses of UV-B absorbing compounds in Nothofagus antartica, N. pumilio, N. betuloides and Rumex sp. in natural conditions show species-specific patterns. The spectrum of N. antartica grown at 38S differs significantly from that of N. antartica in natural conditions in Ushuaia (55S). These results suggest that the selected main area (Patagonia) is appropriate for assessing the problem and its magnitude and that Nothofagus is appropriate for our study.

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  18. Synthesis and characterization of UV-absorbing fluorine-silicone acrylic resin polymer

    NASA Astrophysics Data System (ADS)

    Lei, Huibin; He, Deliang; Guo, Yanni; Tang, Yining; Huang, Houqiang

    2018-06-01

    A series of UV-absorbing fluorine-silicone acrylic resin polymers containing different amount of UV-absorbent were successfully prepared by solution polymerization, with 2-[3-(2H-Benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate (BHEM), vinyltrimethoxysilane (VTMS) and hexafluorobutyl methacrylate (HFMA) as modifying monomers. The acrylic polymers and the coatings thereof were characterized by Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) absorption spectrum, thermogravimetric analysis (TGA), water contact angle (CA) and Xenon lamp artificial accelerated aging tests. Results indicated that the resin exhibited high UV absorption performance as well as good thermal stability. The hydrophobicity of the coatings was of great improvement because of the bonded fluorine and silicone. Meanwhile, the weather-resistance was promoted through preferably colligating the protective effects of BHEM, organic fluorine and silicone. Also, a fitting formula about the weatherability with the BMHE content was tentatively proposed.

  19. Freshwater DOM quantity and quality from a two-component model of UV absorbance

    USGS Publications Warehouse

    Carter, Heather T.; Tipping, Edward; Koprivnjak, Jean-Francois; Miller, Matthew P.; Cookson, Brenda; Hamilton-Taylor, John

    2012-01-01

    We present a model that considers UV-absorbing dissolved organic matter (DOM) to consist of two components (A and B), each with a distinct and constant spectrum. Component A absorbs UV light strongly, and is therefore presumed to possess aromatic chromophores and hydrophobic character, whereas B absorbs weakly and can be assumed hydrophilic. We parameterised the model with dissolved organic carbon concentrations [DOC] and corresponding UV spectra for c. 1700 filtered surface water samples from North America and the United Kingdom, by optimising extinction coefficients for A and B, together with a small constant concentration of non-absorbing DOM (0.80 mg DOC L-1). Good unbiased predictions of [DOC] from absorbance data at 270 and 350 nm were obtained (r2 = 0.98), the sum of squared residuals in [DOC] being reduced by 66% compared to a regression model fitted to absorbance at 270 nm alone. The parameterised model can use measured optical absorbance values at any pair of suitable wavelengths to calculate both [DOC] and the relative amounts of A and B in a water sample, i.e. measures of quantity and quality. Blind prediction of [DOC] was satisfactory for 9 of 11 independent data sets (181 of 213 individual samples).

  20. The near-UV absorber OSSO and its isomers.

    PubMed

    Wu, Zhuang; Wan, Huabin; Xu, Jian; Lu, Bo; Lu, Yan; Eckhardt, André K; Schreiner, Peter R; Xie, Changjian; Guo, Hua; Zeng, Xiaoqing

    2018-05-01

    Disulfur dioxide, OSSO, has been proposed as the enigmatic "near-UV absorber" in the yellowish atmosphere of Venus. However, the fundamentally important spectroscopic properties and photochemistry of OSSO are scarcely documented. By either condensing gaseous SO or 266 laser photolysis of an S2O2 complex in Ar or N2 at 15 K, syn-OSSO, anti-OSSO, and cyclic OS([double bond, length as m-dash]O)S were identified by IR and UV/Vis spectroscopy for the first time. The observed absorptions (λmax) for OSSO at 517 and 390 nm coincide with the near-UV absorption (320-400 nm) found in the Venus clouds by photometric measurements with the Pioneer Venus orbiter. Subsequent UV light irradiation (365 nm) depletes syn-OSSO and anti-OSSO and yields a fourth isomer, syn-OSOS, with concomitant dissociation into SO2 and elemental sulfur.

  1. Distribution and nature of UV absorbers on Triton's surface

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1995-01-01

    Substantial evidence suggests that a UV spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAMs exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SaM material. We hope to determine if UV-SAMs on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAMs has been determined, further constraints on their composition cable made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

  2. Distribution and nature of UV absorbers on Triton's surface

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1994-01-01

    Substantial evidence suggests that a UV Spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAM's exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SAM material. We hope to determine if UV-SAM's on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAM's has been determined, further constraints on their composition can be made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on Voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

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

    NASA Astrophysics Data System (ADS)

    Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

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

  4. Corneal epithelium and UV-protection of the eye.

    PubMed

    Ringvold, A

    1998-04-01

    To study UV-absorption and UV-induced fluorescence in the bovine corneal epithelium. Spectrophotometry and spectrofluorimetry. The corneal epithelium absorbs UV-B radiation mainly owing to its content of protein, RNA, and ascorbate. Some of the absorbed energy is transformed to the less biotoxic UV-A radiation by fluorescence. RNA and ascorbate reduce tissue fluorescence. The corneal epithelium acts as a UV-filter, protecting internal eye structures through three different mechanisms: (1) Absorption of UV-B roughly below 310 nm wavelength. (2) Fluorescence-mediated ray transformation to longer wavelengths. (3) Fluorescence reduction. The extremely high ascorbate concentration in the corneal epithelium has a key role in two of these processes.

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

    PubMed

    Chen, Yi-Ping

    2009-07-01

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

  6. (E)-5-[2-(methoxycarbonyl)ethenyl]cytidine as a chemical actinometer for germicidal UV radiation.

    PubMed

    Shen, Chengyue; Fang, Shiyue; Bergstrom, Donald E; Blatchley, Ernest R

    2005-05-15

    (E)-5-[2-(Methoxycarbonyl)ethenyl]cytidine (S) was examined for use as a chemical actinometer for germicidal UV radiation. Its photoproduct, 3-beta-D-ribofuranosyl-2,7-dioxopyrido[2,3-d]pyrimidine (P), is strongly fluorescent with excitation and emission maxima at 330 and 385 nm, respectively. Experiments were conducted to characterize the dynamic behavior of aqueous solutions of S and P when subjected to UV radiation. UV sources used for these experiments included a low-pressure mercury lamp, a XeBr excimer lamp, and a KrCI excimer lamp; all three sources were mounted in collimating devices to provide incident beams that could be easily and accurately characterized by radiometry. These three sources each yielded essentially monochromatic outputwith characteristic wavelengths of 254, 282, and 222 nm, respectively. At practical concentrations, it was found that the absorbance of the actinometer solution was neither high enough to make the actinometer solutions optically opaque nor low enough to be optically transparent to UV. In addition, the photoproduct displayed a molar absorption coefficient that was similar in magnitude to that of the parent compound, thereby resulting in competitive absorption of UV energy between Sand Pduring irradiation. For purposes of evaluation of the results of irradiation, a mathematical model was developed to accountforthe nonideal optical characteristics of the system. The model is based on a description of local photochemical kinetics; predictions of overall reactor performance were developed by spatial and temporal integration of model results. The model was used to analyze the dynamic behavior of actinometer solutions during UV irradiation and to estimate the quantum yield for photoproduction of Pfrom S. This modeling approach is potentially applicable to other photochemical processes in which multiple compounds are present that absorb photoactive radiation; however, general application of this modeling approach to photochemical

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

    NASA Astrophysics Data System (ADS)

    Häder, D.-P.

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

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

    PubMed

    Hader, D P

    2000-01-01

    Solar UV degrades dissolved organic carbon photolytically so that they can readily be taken up by bacterioplankton. On the other hand solar UV radiation inhibits bacterioplankton activity. Bacterioplankton productivity is far greater than previously thought and is comparable to phytoplankton primary productivity. According to the "microbial loop hypothesis," bacterioplankton is seen in the center of a food web, having a similar function to phytoplankton and protists. The penetration of UV and PAR into the water column can be measured. Marine waters show large temporal and regional differences in their concentrations of dissolved and particulate absorbing substances. A network of dosimeters (ELDONET) has been installed in Europe ranging from Abisko in Northern Sweden to Gran Canaria. Cyanobacteria are capable of fixing atmospheric nitrogen which is then made available to higher plants. The agricultural potential of cyanobacteria has been recognized as a biological fertilizer for wet soils such as in rice paddies. UV-B is known to impair processes such as growth, survival, pigmentation, motility, as well as the enzymes of nitrogen metabolism and CO2 fixation. The marine phytoplankton represents the single most important ecosystem on our planet and produces about the same biomass as all terrestrial ecosystems taken together. It is the base of the aquatic food chain and any changes in the size and composition of phytoplankton communities will directly affect food production for humans from marine sources. Another important role of marine phytoplankton is to serve as a sink for atmospheric carbon dioxide. Recent investigations have shown a large sensitivity of most phytoplankton organisms toward solar short-wavelength ultraviolet radiation (UV-B); even at ambient levels of UV-B radiation many organisms seem to be under UV stress. Because of their requirement for solar energy, the phytoplankton dwell in the top layers of the water column. In this near-surface position

  9. Distribution and nature of UV absorbers on Trition's surface

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1995-01-01

    Substantial evidence suggests that a UV (ultraviolet) Spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAM's exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SAM material. We hope to determine if UV-SAM's on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAM's has been determined, further constraints on their composition can be made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on Voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

  10. [UV-radiation--sources, wavelength, environment].

    PubMed

    Hölzle, Erhard; Hönigsmann, Herbert

    2005-09-01

    The UV-radiation in our environment is part of the electromagnetic radiation, which emanates from the sun. It is designated as optical radiation and reaches from 290-4,000 nm on the earth's surface. According to international definitions UV irradiation is divided into short-wave UVC (200-280 nm), medium-wave UVB (280-320 nm), and long-wave UVA (320-400 nm). Solar radiation which reaches the surface of the globe at a defined geographical site and a defined time point is called global radiation. It is modified quantitatively and qualitatively while penetrating the atmosphere. Besides atmospheric conditions, like ozone layer and air pollution, geographic latitude, elevation, time of the season, time of the day, cloudiness and the influence of indirect radiation resulting from stray effects in the atmosphere and reflection from the underground play a role in modifying global radiation, which finally represents the biologically effective radiation. The radiation's distribution on the body surface varies according to sun angle and body posture. The cumulative UV exposure is mainly influenced by outdoor profession and recreational activities. The use of sun beds and phototherapeutic measures additionally may contribute to the cumulative UV dose.

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

    PubMed

    Kataria, Sunita; Guruprasad, K N

    2015-12-01

    Field studies were conducted to determine the potential for alterations in photosynthetic performance and grain yield of four wheat (Triticum aestivum) varieties of India- Vidisha, Purna, Swarna and Naveen Chandausi by ambient ultraviolet radiation (UV). The plants were grown in specially designed UV exclusion chambers, wrapped with filters that excluded UV-B (<315 nm), UV-A/B (<400 nm) or transmitted ambient UV or lacked filters. The results indicated that solar UV exclusion increased the leaf mass per area ratio, leaf weight ratio and chlorophylls per unit area of flag leaves in all the four varieties of wheat. Polyphasic chlorophyll a fluorescence transients from the flag leaves of UV excluded wheat plants gave a higher fluorescence yield. Exclusion of solar UV significantly enhanced photosynthetic performance as a consequence of increased efficiency of PS II, performance index (PIABS) and rate of photosynthesis in the flag leaves of wheat varieties along with a remarkable increase in carbonic anhydrase, Rubisco and nitrate reductase activities. This additional fixation of carbon and nitrogen by exclusion of UV was channelized towards the improvement in grain yield of wheat varieties as there was a decrease in the UV-B absorbing substances and an increase in soluble protein content in flag leaves of all the four varieties of wheat. The magnitude of response for UV exclusion for all the measured parameters was higher in two varieties of wheat Vidisha and Purna as compared to Swarna and Naveen Chandausi. Cumulative stress response index (CSRI) for each variety was developed from the cumulative sum of physiological and yield parameters such as leaf mass area ratio of flag leaf, total chlorophyll content, performance index at absorption basis, rate of photosynthesis and grain yield. All the varieties had a negative CSRI, demonstrating a negative impact of ambient UV radiation. Naveen Chandausi and Swarna are less sensitive to ambient UV radiation; Vidisha is more

  12. Effect of UV-B Radiation and Desiccation Stress on Photoprotective Compounds Accumulation in Marine Leptolyngbya sp.

    PubMed

    Joshi, Devika; Mohandass, C; Dhale, Mohan

    2018-01-01

    Increased awareness regarding the harmful effects of ultraviolet (UV)-B radiation has led to the search for new sources of natural UV-B protecting compounds. Mycosporine-like amino acids are one of such promising compounds found in several organisms. Cyanobacteria are ideal organisms for isolation of these compounds due to their compatibility and adaptability to thrive under harsh environmental conditions. In the following investigation, we report the production of shinorine in Leptolyngbya sp. isolated from the intertidal region. Based on the spectral characteristics and liquid chromatography-mass spectrometry analysis, the UV-absorbing compound was identified as shinorine. To the best of our knowledge, this is the first report on the occurrence of shinorine in Leptolyngbya sp. We also investigated the effect of artificial UV-B radiation and periodic desiccation on chlorophyll-a, total carotenoids, and mycosporine-like amino acids (MAAs) production. The UV-B radiation had a negative effect on growth and chlorophyll concentration, whereas it showed an inductive effect on the production of total carotenoids and MAAs. Desiccation along with UV-B radiation led to an increase in the concentration of photoprotective compounds. These results indicate that carotenoids and MAAs thus facilitate cyanobacteria to avoid and protect themselves from the deleterious effects of UV-B and desiccation.

  13. The effects of enhanced UV-B radiation on growth, stomata, flavonoid, and ABA content in cucumber leaves

    NASA Astrophysics Data System (ADS)

    An, Lizhe; Wang, Jianhui; Liu, Yanhong; Chen, Tuo; Xu, Shijian; Feng, Huyuan; Wang, Xunling

    2003-06-01

    Cucumber plants (Cucumis sativus L. cv. Jinchun No 3) grown in a greenhouse were treated with three different biologically effective ultraviolet-B (UV-B) radiation levels: 1.28 kJ. m-2 (CK), 8.82kJ.m-2 (T1) and 12.6 kJ. m-2 (T2). Irradiances corresponded to 8% and 21% reduction in stratospheric ozone in Lanzhou. Plants at three-leaf stage were irradiated 7 h daily for 25 days. The growth, stomata, flavonoid and ABA content in cucumber leaves exposed to 3 levels of UV-B radiation were determined in this paper. The results indicated that, compared with the control after 25 days UV-B radiation, RI of cucumber under T1 treatment is -18.0% and RI under T2 treatment is -48% mostly because of the reduce of leave area and dry weight accompanying with the increase of SLW; the rate of stomata closure under the treatments of T1 and T2 on the 6th day was up to respectively 70% and 89%, and amounted to 90% and 100% on the 18th day, and the guard cells in some stomata apparatus became permanent pores and lost their function at the same time; with the duration of UV-B radiation, the rise of the absorbance to ultraviolet light (305nm) showed the content increase of flavonoid; Abscisic acid (ABA) was determined by means of ELISA which showed that under the T1 treatment, the content of ABA was up to maximum to 510% higher than that of the control on the 21st day, meanwhile, under the treatment of T2, it was the highest on the 18th day to 680% of the control, and then had a decrease tendency on 21st day. The result still indicated that ABA accumulation could be induced by enhanced UV-B the radiation. The bigger was the dose of radiation, the higher was the accumulation of ABA. When intensity of UV-B radiation went beyond the degree of endurance of cucumber plants, ABA content descended then. Cucumber plants resist enhanced UV-B radiation by means of improving the contents of ABA and flavonoid. The increase of ABA content in cucumber leaves could lead to the stomata closure. Therefore

  14. Photophysical properties of hexyl diethylaminohydroxybenzoylbenzoate (Uvinul A Plus), a UV-A absorber.

    PubMed

    Shamoto, Yuta; Yagi, Mikio; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Kikuchi, Azusa

    2017-09-13

    Hexyl diethylaminohydroxybenzoylbenzoate (DHHB, Uvinul A Plus) is a photostable UV-A absorber. The photophysical properties of DHHB have been studied by obtaining the transient absorption, total emission, phosphorescence and electron paramagnetic resonance spectra. DHHB exhibits an intense phosphorescence in a hydrogen-bonding solvent (e.g., ethanol) at 77 K, whereas it is weakly phosphorescent in a non-hydrogen-bonding solvent (e.g., 3-methylpentane). The triplet-triplet absorption and EPR spectra for the lowest excited triplet state of DHHB were observed in ethanol, while they were not observed in 3-methylpentane. These results are explained by the proposal that in the benzophenone derivatives possessing an intramolecular hydrogen bond, intramolecular proton transfer is an efficient mechanism of the very fast radiationless decay from the excited singlet state. The energy level of the lowest excited triplet state of DHHB is higher than those of the most widely used UV-B absorbers, octyl methoxycinnamate (OMC) and octocrylene (OCR). DHHB may act as a triplet energy donor for OMC and OCR in the mixtures of UV-A and UV-B absorbers. The bimolecular rate constant for the quenching of singlet oxygen by DHHB was determined by measuring the near-IR phosphorescence of singlet oxygen. The photophysical properties of diethylaminohydroxybenzoylbenzoic acid (DHBA) have been studied for comparison. It is a closely related building block to assist in interpreting the observed data.

  15. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    PubMed

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. UV RADIATION MEASUREMENTS/ATMOSPHERIC CHARACTERIZATION

    EPA Science Inventory

    Because exposure to ultraviolet (UV) radiation is an ecosystem stressor and poses a human health risk, the National Exposure Research Laboratory (NERL) has undertaken a research program to measure the intensity of UV-B radiation at various locations throughout the U.S. In Septem...

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

  19. Effect of ultraviolet light absorbers on photostabilization of azadirachtin-A in solution (part: II).

    PubMed

    Deota, P T; Upadhyay, P R; Valodkar, V B

    2003-01-01

    The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1:1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.

  20. Oceanic protection of prebiotic organic compounds from UV radiation

    NASA Technical Reports Server (NTRS)

    Cleaves, H. J.; Miller, S. L.; Bada, J. L. (Principal Investigator)

    1998-01-01

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

  1. Leaf expansion and development of photosynthetic capacity and pigments in Liquidambar Styraciflua (Hamamelidaceae)-effects of UV-B radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dillenburg, L.R.; Sullivan, J.H.; Teramura, A.H.

    1995-07-01

    In order to perform their functions as photosynthetic organs, leaves must cope with excess heat and potentially damaging ultraviolet radiation. Possible increases in the UV-B portion of the solar spectrum may place an additional burden on leaves, and this could be particularly important for young expanding leaves with poorly developed UV-B defense mechanisms. We evaluated the effects of supplemental UV-B radiation on leaf expansion and the development of photosynthetic capacity and pigments in sweetgum (Liquidambar styraciflua L.) seedlings. Seedlings were grown in the field under either ambient or ambient plus 3 or 5.0 kJ of biologically effective supplemental UV-B radiation.more » Although final leaf size was unaffected, the rate of leaf elongation and accumulation of leaf area was slower in leaves exposed to the lower supplemental UV-B irradiance. In contrast, chlorophyll accumulation and the development of photosynthetic capacity was more rapid in plants exposed to the higher, compared to the lower supplemental UV-B irradiance. The accumulation of anthocyanins and other putative flavonoids or UV-absorbing compounds was scarcely affected by exposure to supplemental UV-B radiation. These results suggest that the UV-B portion of the solar spectrum may, in the absence of gross affects on biomass, exert subtle influences on leaf ontogeny and the development of photosynthetic pigments and capacity in sweetgum. 44 refs., 6 figs.« less

  2. Simultaneous UV and X-ray Spectroscopy of the Seyfert 1 Galaxy NGC 5548. I: Physical Conditions in the UV Absorbers

    NASA Technical Reports Server (NTRS)

    Crenshaw, D. M.; Kraemer, S. B.; Gabel, J. R.; Kaastra, J. S.; Steenbrugge, K. C.; Brinkman, A. C.; Dunn, J. P.; George, I. M.; Liedahl, D. A.; Paerels, F. B. S.

    2003-01-01

    We present new UV spectra of the nucleus of the Seyfert 1 galaxy NGC 5548, which we obtained with the Space Telescope Imaging Spectrograph at high spectral resolution, in conjunction with simultaneous Chandra X-ray Observatory spectra. Taking advantage of the low UV continuum and broad emission-line fluxes, we have determined that the deepest UV absorption component covers at least a portion of the inner, high-ionization narrow-line region (NLR). We find nonunity covering factors in the cores of several kinematic components, which increase the column density measurements of N V and C IV by factors of 1.2 to 1.9 over the full-covering case; however, the revised columns have only a minor effect on the parameters derived from our photoionization models. For the first time, we have simultaneous N V and C IV columns for component 1 (at -1040 km/s), and find that this component cannot be an X-ray warm absorber, contrary to our previous claim based on nonsimultaneous observations. We find that models of the absorbers based on solar abundances severely overpredict the O VI columns previously obtained with the Far Ultraviolet Spectrograph, and present arguments that this is not likely due to variability. However, models that include either enhanced nitrogen (twice solar) or dust, with strong depletion of carbon in either case, are successful in matching all of the observed ionic columns. These models result in substantially lower ionization parameters and total column densities compared to dust-free solar-abundance models, and produce little O VII or O VIII, indicating that none of the UV absorbers are X-ray warm absorbers.

  3. UV-visible absorbance spectroscopy as a proxy for peatland dissolved organic carbon (DOC) quantity and quality: considerations on wavelength and absorbance degradation.

    PubMed

    Peacock, Mike; Evans, Chris D; Fenner, Nathalie; Freeman, Chris; Gough, Rachel; Jones, Timothy G; Lebron, Inma

    2014-05-01

    Absorbance in the UV or visible spectrum (UV-vis) is commonly used as a proxy for DOC concentrations in waters draining upland catchments. To determine the appropriateness of different UV-vis measurements we used surface and pore water samples from two Welsh peatlands in four different experiments: (i) an assessment of single wavelength proxies (1 nm increments between 230-800 nm) for DOC concentration demonstrated that 254 nm was more accurate than 400 nm. The highest R(2) values between absorbance and DOC concentration were generated using 263 nm for one sample set (R(2) = 0.91), and 230 nm for the other three sample sets (respective R(2) values of 0.86, 0.81, and 0.93). (ii) A comparison of different DOC concentration proxies, including single wavelength proxies, a two wavelength model, a proxy using phenolic concentration, and a proxy using the area under a UV spectrum at 250-350 nm. It was found that both a single wavelength proxy (≤263 nm) and a two wavelength model performed well for both pore water and surface water. (iii) An evaluation of the E2 : E3, E2 : E4, E4 : E6 ratios, and SUVA (absorbance at 254 nm normalised to DOC concentration) as indicators of DOC quality showed that the E4 : E6 ratio was subject to extensive variation over time, and was highly correlated between surface water and pore water, suggesting that it is a useful metric to determine temporal changes in DOC quality. (iv) A repeated weekly analysis over twelve weeks showed no consistent change in UV-vis absorbance, and therefore an inferred lack of degradation of total DOC in samples that were filtered and stored in the dark at 4 °C.

  4. UV-B Radiation Contributes to Amphibian Population Declines

    NASA Astrophysics Data System (ADS)

    Blaustein, Andrew

    2007-05-01

    UV-B (280-315 nm) radiation is the most significant biologically damaging radiation at the terrestrial surface. At the organismal level, UV-B radiation can slow growth rates, cause immune dysfunction and result in sublethal damage. UV-B radiation can lead to mutations and cell death. Over evolutionary time, UV radiation has been an important stressor on living organisms. Natural events, including impacts from comets and asteroids, volcanic activity, supernova explosions and solar flares, can cause large-scale ozone depletion with accompanying increases in UV radiation. However, these natural events are transient. Moreover, the amount of ozone damage due to natural events depends upon a number of variables, including the magnitude of the event. This is different from modern-day human-induced production of chlorofluorocarbons (CFCs) and other chemicals that deplete stratospheric ozone continuously, resulting in long-term increases in UV-B radiation at the surface of the earth. We will briefly review the effects of UV-B exposure in one group of aquatic organisms_amphibians. UV-B has been implicated as a possible factor contributing to global declines and range reductions in amphibian populations.

  5. Solar UV-A and UV-B radiation fluxes at two Alpine stations at different altitudes

    NASA Astrophysics Data System (ADS)

    Blumthaler, M.; Ambach, W.; Rehwald, W.

    1992-03-01

    Daily totals of UV-A and UV-B radiation fluxes and global radiation were measured since 1981 at Jungfraujoch (3576 m) a.s.l.) and in Innsbruck (577 m a.s.l.) in their seasonal course. The altitude effect of annual totals yields 19%/1000 m (UV-B), 11%/1000 m (UV-A) and 9%/1000 m (global radiation) with reference to Innsbruck station. The ratio of the daily totals of UV-B/global radiation shows a significant seasonal course with the maximum in summer, whereas the ratio of the daily totals of UV-A/global radiation shows no significant seasonal variation. The biological effective doses of erythema reaction, delayed tanning and immediate tanning by UV-A and UV-B radiant exposure are reported in the seasonal course at Jungfraujoch and in Innsbruck.

  6. UV dichroic coatings on metallic reflectors

    NASA Astrophysics Data System (ADS)

    Raghunath, C.; Babu, N. J.; chandran, K. M.

    2008-05-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail.

  7. A depleted ozone layer absorbs less UV-B, cooling the ozone layer, increasing the amount of UV-B observed to reach Earth, heating air by dissociating tropospheric and ground-level ozone, and heating oceans very efficiently by penetrating tens of meters into the mixed layer. UV-B is 48 times more energetic ("hotter") than IR absorbed by greenhouse gases

    NASA Astrophysics Data System (ADS)

    Ward, P. L.

    2017-12-01

    This new insight into the physics of radiation shows why changes in stratospheric ozone are observed to cause changes in global temperature. By 1970, manufactured CFC gases and ozone depletion began increasing. By 1993, increases in CFCs stopped as mandated by the Montreal Protocol. By 1995, increases in ozone depletion stopped. By 1998, increases in temperature stopped until 2014. Ozone is also depleted by halogen gases emitted from major basaltic lava flows, the largest of which, since 1783, occurred at Bardarbunga in Iceland in 2014, causing 2015 and 2016 to be the hottest years on record. Throughout Earth history, the largest basaltic lava flows were contemporaneous with periods of greatest warming and greatest levels of mass extinctions. Planck's empirical law shows that temperature of matter results from oscillation of all the bonds holding matter together. The higher the temperature, the higher the frequencies and amplitudes of oscillation. Thus, radiation from a nearby hotter body will make the absorbing body hotter than radiation from a cooler body. According to the Planck-Einstein relation, thermal energy (E) in matter and in radiation equals frequency of oscillation (ν) times the Planck constant (h), E=hν—the energy of a frictionless atomic oscillator. Since frequency is observed to be a very broad continuum extending from radio signals through visible light to gamma rays, thermal energy (E=hν) must also be a very broad continuum. Thermal flux cannot be represented properly by a single number of watts per square meter, as commonly assumed throughout the physical sciences, because all frequencies coexist and the number of watts increases with frequency. Thus, UV-B solar radiation is 48 times more energetic than IR terrestrial radiation absorbed by greenhouse gases and can make the absorbing body 48 times hotter. UV-B causes sunburn; no amount of IR can cause sunburn. Furthermore, in a basic experiment, I show that air containing more than 23 times

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

    PubMed

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

    2015-08-01

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

  9. Promotion by humus-reducing bacteria for the degradation of UV254 absorbance in reverse-osmosis concentrates pretreated with O3-assisted UV-Fenton method.

    PubMed

    Xia, Jiaohui; Zhang, Hui; Ding, Shaoxuan; Li, Changyu; Ding, Jincheng; Lu, Jie

    2017-07-12

    The primary pollutants in reverse-osmosis concentrates (ROC) are the substances with the UV absorbance at 254 nm (UV 254 ), which is closely related to humic substances that can be degraded by humus-reducing bacteria. This work studied the degradation characteristics of humus-reducing bacteria in ROC treatment. The physiological and biochemical characteristics of humus-reducing bacteria were investigated, and the effects of pH values and electron donors on the reduction of humic analog, antraquinone-2, 6-disulfonate were explored to optimize the degradation. Furthermore, the O 3 -assisted UV-Fenton method was applied for the pretreatment of ROC, and the degradation of UV 254 absorbance was apparently promoted with their removal rate, reaching 84.2% after 10 days of degradation by humus-reducing bacteria.

  10. Degradation and mineralization of organic UV absorber compound 2-phenylbenzimidazole-5-sulfonic acid (PBSA) using UV-254nm/H2O2.

    PubMed

    Abdelraheem, Wael H M; He, Xuexiang; Duan, Xiaodi; Dionysiou, Dionysios D

    2015-01-23

    Various studies have revealed the non-biodegradable and endocrine disrupting properties of sulfonated organic UV absorbers, directing people's attention toward their risks on ecological and human health and hence their removal from water. In this study, UV-254nm/H2O2 advanced oxidation process (AOP) was investigated for degrading a model UV absorber compound 2-phenylbenzimidazole-5-sulfonic acid (PBSA) and a structurally similar compound 1H-benzimidazole-2-sulfonic acid (BSA), with a specific focus on their mineralization. At 4.0mM [H2O2]0, a complete removal of 40.0μM parent PBSA and 25% decrease in TOC were achieved with 190min of UV irradiation; SO4(2-) was formed and reached its maximum level while the release of nitrogen as NH4(+) was much lower (around 50%) at 190min. Sulfate removal was strongly enhanced by increasing [H2O2]0 in the range of 0-4.0mM, with slight inhibition in 4.0-12.0mM. Faster and earlier ammonia formation was observed at higher [H2O2]0. The presence of Br(-) slowed down the degradation and mineralization of both compounds while a negligible effect on the degradation was observed in the presence of Cl(-). Our study provides important technical and fundamental results on the HO based degradation and mineralization of SO3H and N-containing UV absorber compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Short- and long-term physiological responses of grapevine leaves to UV-B radiation.

    PubMed

    Martínez-Lüscher, J; Morales, F; Delrot, S; Sánchez-Díaz, M; Gomés, E; Aguirreolea, J; Pascual, I

    2013-12-01

    The present study aimed at evaluating the short- and long-term effects of UV-B radiation on leaves of grapevine Vitis vinifera (cv. Tempranillo). Grapevine fruit-bearing cuttings were exposed to two doses of supplemental biologically effective UV-B radiation (UV-BBE) under glasshouse-controlled conditions: 5.98 and 9.66kJm(-2)d(-1). The treatments were applied either for 20d (from mid-veraison to ripeness) or 75d (from fruit set to ripeness). A 0kJm(-2)d(-1) UV-B treatment was included as control. The main effects of UV-B were observed after the short-term exposure (20d) to 9.66kJm(-2)d(-1). Significant decreases in net photosynthesis, stomatal conductance, sub-stomatal CO2 concentration, the actual photosystem II (PSII) efficiency, total soluble proteins and de-epoxidation state of the VAZ cycle were observed, whereas the activities of several antioxidant enzymes increased significantly. UV-B did not markedly affect dark respiration, photorespiration, the maximum potential PSII efficiency (Fv/Fm), non-photochemical quenching (NPQ), as well as the intrinsic PSII efficiency. However, after 75d of exposure to 5.98and 9.66kJm(-2)d(-1) UV-B most photosynthetic and biochemical variables were unaffected and there were no sign of oxidative damage in leaves. The results suggest a high long-term acclimation capacity of grapevine to high UV-B levels, associated with a high accumulation of UV-B absorbing compounds in leaves, whereas plants seemed to be tolerant to moderate doses of UV-B. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. A novel research model for evaluating sunscreen protection in the UV-A1.

    PubMed

    Figueiredo, Sônia Aparecida; de Moraes, Dayane Cristina; Vilela, Fernanda Maria Pinto; de Faria, Amanda Natalina; Dos Santos, Marcelo Henrique; Fonseca, Maria José Vieira

    2018-01-01

    The use of a broad spectrum sunscreen is considered one of the main and most popular measures for preventing the damaging effects of ultraviolet radiation (UVR) on the skin. In this study we have developed a novel in vitro method to assess sunscreens efficacy to protect calcineurin enzyme activity, a skin cell marker. The photoprotective efficacy of sunscreen products was assessed by measuring the UV-A1 radiation-induced depletion of calcineurin (Cn) enzyme activity in primary neonatal human dermal fibroblast (HDFn) cell lysates. After exposure to 24J/cm 2 UV-A1 radiation, the sunscreens containing larger amounts of UV-A1 filters (brand B), the astaxanthin (UV-A1 absorber) and the Tinosorb® M (UV-A1 absorber) were capable of preventing loss of Cn activity when compared to the sunscreens formulations of brand A (low concentration of UV-A1 filters), with the Garcinia brasiliensis extract (UV-B absorber) and with the unprotected cell lysate and exposed to irradiation (Irradiated Control - IC). The Cn activity assay is a reproducible, accurate and selective technique for evaluating the effectiveness of sunscreens against the effects of UV-A1 radiation. The developed method showed that calcineurin activity have the potential to act as a biological indicator of UV-A1 radiation-induced damages in skin and the assay might be used to assess the efficacy of sunscreens agents and plant extracts prior to in vivo tests. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Simultaneous UV and X-ray Spectroscopy of the Seyfert 1 Galaxy NGC 5548. I. Evidence for Dust in the UV Absorbers

    NASA Astrophysics Data System (ADS)

    Kraemer, S. B.; Crenshaw, D. M.; Gabel, J. R.; Kaastra, J. S.; Steenbrugge, K.; George, I. M.; Turner, T. J.; Yaqoob, T.; Dunn, J. P.

    2002-12-01

    We present new UV spectra of the nucleus of the Seyfert 1 galaxy NGC 5548, obtained with the Space Telescope Imaging Spectrograph at high spectral resolution (λ /Δ λ = 30,000 - 46,000), simultaneously with Chandra X-ray Observatory spectra. Taking advantage of the low UV continuum and broad emission-line fluxes, we have determined that the deepest UV absorption component covers at least a portion of the inner high-ionization narrow-line region (NLR). Assuming the NLR is fully covered, we find nonunity covering factors in the cores of several components, which increase the column density measurements of N V and C IV by factors of 1.2 to 1.9; however, the revised columns have only a minor effect on the parameters derived from our photoionization models. For the first time, we have simultaneous C IV and N V columns for component 1 (at -1040 km s-1), and find that this component cannot be an X-ray warm absorber, contrary to our previous claim (based on nonsimultaneous observations of N V and C IV). We find that dust-free models of the absorbers severely overpredict the O VI columns previously obtained with the Far Ultraviolet Spectrograph, and present arguments that this is not likely due to variability. However, models that include dust (and thereby heavily deplete carbon) are successful in matching all of the observed ionic columns, and result in substantially lower ionization parameters and total column densities compared to dust-free models. Interestingly, these models yield the exact amount of dust needed to produce the observed reddening of the inner NLR, assuming a Galactic dust to gas ratio. The models produce little O VII and O VIII, indicating that none of the dusty UV absorbers is associated with a classic X-ray warm absorber.

  14. The role of solar UV radiation in the ecology of alpine lakes.

    PubMed

    Sommaruga, R

    2001-09-01

    Solar ultraviolet radiation (UVR, 290-400 nm) is a crucial environmental factor in alpine lakes because of the natural increase of the UVR flux with elevation and the high water transparency of these ecosystems. The ecological importance of UVR, however, has only recently been recognized. This review, examines the general features of alpine lakes regarding UVR, summarizes what is known about the role of solar UVR in the ecology of alpine lakes, and identifies future research directions. Unlike the pattern observed in most lowland lakes, variability of UV attenuation in alpine lakes is poorly explained by differences in dissolved organic carbon (DOC) concentrations, and depends mainly on optical characteristics (absorption) of the chromophoric dissolved organic matter (CDOM). Within the water column of lakes with low DOC concentrations (0.2-0.4 mg l(-1)), UV attenuation is influenced by phytoplankton whose development at depth (i.e. the deep chlorophyll maximum) causes important changes in UV attenuation. Alpine aquatic organisms have developed a number of strategies to minimize UV damage. The widespread synthesis or bioaccumulation of different compounds that directly or indirectly absorb UV energy is one such strategy. Although most benthic and planktonic primary producers and crustacean zooplankton are well adapted to high intensities of solar radiation, heterotrophic protists, bacteria, and viruses seem to be particularly sensitive to UVR. Understanding the overall impact of UVR on alpine lakes would need to consider synergistic and antagonistic processes resulting from the pronounced climatic warming, which have the potential to modify the UV underwater climate and consequently the stress on aquatic organisms.

  15. Effect of Aerosols on Surface Radiation and Air Quality in the Central American Region Estimated Using Satellite UV Instruments

    NASA Astrophysics Data System (ADS)

    Bhartia, P. K.; Torres, O.; Krotkov, N. A.

    2007-05-01

    Solar radiation reaching the Earth's surface is reduced by both aerosol scattering and aerosol absorption. Over many parts of the world the latter effect can be as large or larger than the former effect, and small changes in the aerosol single scattering albedo can either cancel the former effect or enhance it. In addition, absorbing aerosols embedded in clouds can greatly reduce the amount of radiation reaching the surface by multiple scattering. Though the potential climatic effects of absorbing aerosols have received considerable attention lately, their effect on surface UV, photosynthesis, and photochemistry can be equally important for our environment and may affect human health and agricultural productivity. Absorption of all aerosols commonly found in the Earth's atmosphere becomes larger in the UV and blue wavelengths and has a relatively strong wavelength dependence. This is particularly true of mineral dust and organic aerosols. However, these effects have been very difficult to estimate on a global basis since the satellite instruments that operate in the visible are primarily sensitive to aerosol scattering. A notable exception is the UV Aerosol Index (AI), first produced using NASA's Nimbus-7 TOMS data. AI provides a direct measure of the effect of aerosol absorption on the backscattered UV radiation in both clear and cloudy conditions, as well as over snow/ice. Although many types of aerosols produce a distinct color cast in the visible images, and aerosols absorption over clouds and snow/ice could, in principle be detected from their color, so far this technique has worked well only in the UV. In this talk we will discuss what we have learned from the long-term record of AI produced from TOMS and Aura/OMI about the possible role of aerosols on surface radiation and air quality in the Central American region.

  16. Response of biological uv dosimeters to the simulated extraterrestrial uv radiation

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Rontó, G.; Kerékgyártó, T.; Kovács, G.; Lammer, H.

    In the Laboratory polycrystalline uracil thin layer and bacteriophage T7 detectors have been developed for UV dosimetry on the EarthSs surface. Exponential response of the uracil polycrystal has been detected both by absorption spectroscopy and measurements of the refractive index under the influence of terrestrial solar radiation or using UV-C sources. In UV biological dosimetry the UV dose scale is additive starting at a value of zero according to the definition of CIE (Technical Report TC-6-18). The biological dose can be defined by a measured end-effect. In our dosimeters (phage T7 and uracil dosimeter) exposed to natural (terrestrial) UV radiation the proportion of pyrimidin photoproducts among the total photoproducts is smaller than 0.1 and the linear correlation between the biological and physical dose is higher than 0.9. According to the experimental data this linear relationship is often not valid. We observed that UV radiation did not only induce dimerisation but shorter wavelengths caused monomerisation of pyrimidin dimers. Performing the irradiation in oxygen free environment and using a Deuterium lamp as UV source, we could increase monomerisation against dimerisation thus the DNA-based dosimetrySs additivity rule is not fulfilled in these conditions. In this study we will demonstrate those non-linear experiments which constitute the basis of our biological experiments on the International Space Station.

  17. Cathodoluminescent UV-radiation sources

    NASA Astrophysics Data System (ADS)

    Vereschagina, N. Y.; Danilkin, M. I.; Kazaryan, M. A.; Ozol, D. I.; Sheshin, E. P.; Spassky, D. A.

    2018-04-01

    Mercury-free UV-radiation sources are described. An electron beam similar to cathode-ray tubes (CRT) excites a luminescent material in a vacuum bulb. A high density of excitation requires the cathode and the luminescent material to be resistant for that and provide the extended lifetime of the UV-radiation source. Carbon fibre and nano-carbon based field-emission cathodes produce long lasting stable emission with a high current density (up to 0.3-0.5 A/cm2 ). Li2B4O7:Cu and Li2B4O7:Ag luminescent ceramics survive under high radiation doses and provide UV luminescence bands peaked at 360-370 nm and 270 nm, respectively. The luminescence band at 360-370 nm has a good overlap with the fundamental absorption edge of TiO2, which is known as a photo-catalyst in air and water cleaning systems. The luminescence band at 270 nm overlaps with DNA absorption and provides a direct disinfection effect. We suggest the structure of complex luminescence centres and energy transfer mechanisms. The electron structure of lithium tetraborate and the contribution of impurities are also discussed in paper.

  18. Probing Jupiter's Radiation Environment with Juno-UVS

    NASA Astrophysics Data System (ADS)

    Kammer, J.; Gladstone, R.; Greathouse, T. K.; Hue, V.; Versteeg, M. H.; Davis, M. W.; Santos-Costa, D.; Becker, H. N.; Bolton, S. J.; Connerney, J. E. P.; Levin, S.

    2017-12-01

    While primarily designed to observe photon emission from the Jovian aurora, Juno's Ultraviolet Spectrograph (Juno-UVS) has also measured background count rates associated with penetrating high-energy radiation. These background counts are distinguishable from photon events, as they are generally spread evenly across the entire array of the Juno-UVS detector, and as the spacecraft spins, they set a baseline count rate higher than the sky background rate. During eight perijove passes, this background radiation signature has varied significantly on both short (spin-modulated) timescales, as well as longer timescales ( minutes to hours). We present comparisons of the Juno-UVS data across each of the eight perijove passes, with a focus on the count rate that can be clearly attributed to radiation effects rather than photon events. Once calibrated to determine the relationship between count rate and penetrating high-energy radiation (e.g., using existing GEANT models), these in situ measurements by Juno-UVS will provide additional constraints to radiation belt models close to the planet.

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

    NASA Astrophysics Data System (ADS)

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

    2003-11-01

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

  20. Effects of UV radiation on phytoplankton

    NASA Astrophysics Data System (ADS)

    Smith, Raymond C.; Cullen, John J.

    1995-07-01

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

  1. Fabrication and characterization of UV-emitting nanoparticles as novel radiation sensitizers targeting hypoxic tumor cells

    NASA Astrophysics Data System (ADS)

    Squillante, Michael R.; Jüstel, Thomas; Anderson, R. Rox; Brecher, Charles; Chartier, Daniel; Christian, James F.; Cicchetti, Nicholas; Espinoza, Sara; McAdams, Daniel R.; Müller, Matthias; Tornifoglio, Brooke; Wang, Yimin; Purschke, Martin

    2018-06-01

    Radiation therapy is one of the primary therapeutic techniques for treating cancer, administered to nearly two-thirds of all cancer patients. Although largely effective in killing cancer cells, radiation therapy, like other forms of cancer treatment, has difficulty dealing with hypoxic regions within solid tumors. The incomplete killing of cancer cells can lead to recurrence and relapse. The research presented here is investigating the enhancement of the efficacy of radiation therapy by using scintillating nanoparticles that emit UV photons. UV photons, with wavelengths between 230 nm and 280 nm, are able to inactivate cells due to their direct interaction with DNA, causing a variety of forms of damage. UV-emitting nanoparticles will enhance the treatment in two ways: first by generating UV photons in the immediate vicinity of cancer cells, leading to direct and oxygen-independent DNA damage, and second by down-converting the applied higher energy X-rays into softer X-rays and particles that are more efficiently absorbed in the targeted tumor region. The end result will be nanoparticles with a higher efficacy in the treatment of hypoxic cells in the tumor, filling an important, unmet clinical need. Our preliminary experiments show an increase in cell death using scintillating LuPO4:Pr nanoparticles over that achieved by the primary radiation alone. This work describes the fabrication of the nanoparticles, their physical characterization, and the spectroscopic characterization of the UV emission. The work also presents in vitro results that demonstrate an enhanced efficacy of cell killing with x-rays and a low unspecific toxicity of the nanoparticles.

  2. Reproductive, morphological, and phytochemical responses of Arabidopsis thaliana ecotypes to enhanced UV-B radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Trumbull, V.L.; McCloud, E.S.; Paige, K.N.

    1994-06-01

    Two ecotypes of Arabidopsis thaliana, collected from Libya and Norway, were grown in the greenhouse under. UV-B doses of 0 and 10.5 kJ m[sup [minus]2] UV-B[sub BE]. The high UV-B dose simulated midsummer ambient conditions over Libya and a 40% reduction in stratospheric ozone over Norway. The Libyan ectotype, which originated from latitudes where solar UV-B is high, showed no UV-B induced damage to plant growth. However the Norwegian ecotype, which originated from latitudes where solar UV-B is low, showed a significant reduction in plant height, inflorescence weight, and rosette weight in response to enhanced UV-B. Although fruit and seedmore » number for both ecotypes were unaffected by enhanced UV-B radiation the germination success of the seeds harvested from the irradiated Norwegian plants were significantly reduced. The two ecotypes also differed with respect to their accumulation of kaempferol, a putative UV-B protective filter. The Libyan ecotype increased kaempferol concentration by 38% over the 0 kJ treatment whereas the Norwegian ecotype increased by only 15%. These data suggest that, for these ecotypes, variation in UV-B sensitivity may be explained by the differential induction of UV-absorbing leaf pigments.« less

  3. Bacterial Sunscreen: Layer-by-Layer Deposition of UV-Absorbing Polymers on Whole-Cell Biosensors (POSTPRINT)

    DTIC Science & Technology

    2012-06-13

    mycosporine - like amino acids that absorb in the UV range and can quench UV-induced intracellular free radicals.2,3 Common in both microorganisms and higher...oxygen, which will react with amino acid side chains and reduce protein stability. GFPuv is excited by long-wave UV and requires ionization for...vinyl sulfate, poly-4-styrenesulfonic acid , and humic acid ) were used to encapsulate E. coli cells expressing green fluorescent protein (GFP) either

  4. Combined Effects of UVR and Temperature on the Survival of Crab Larvae (Zoea I) from Patagonia: The Role of UV-Absorbing Compounds

    PubMed Central

    Hernández Moresino, Rodrigo D.; Helbling, E. Walter

    2010-01-01

    The aim of our study was to assess the combined impact of UVR (280–400 nm) and temperature on the first larval stage (Zoea I) of three crab species from the Patagonian coast: Cyrtograpsus altimanus, C. angulatus, and Leucippa pentagona. We determined the survival response of newly hatched Zoea I after being exposed for 8–10 h under a solar simulator (Hönle SOL 1200) at 15 and 20 °C. There was no mortality due to Photosynthetic Active Radiation (PAR, 400–700 nm) or ultraviolet-A radiation (UV-A, 315–400 nm), and all the observed mortality was due to ultraviolet-B radiation (UV-B, 280–315 nm). The data of larval mortality relative to exposure time was best fit using a sigmoid curve. Based on this curve, a threshold (Th) and the lethal dose for 50% mortality (LD50) were determined for each species. Based on the Th and LD50, C. altimanus was found to be the most resistant species, while L. pentagona was found to be the most sensitive to UV-B. For both species of Cyrtograpsus, mortality was significantly lower at 20 °C than at 15 °C; however, no significant differences between the two temperature treatments were found in L. pentagona. Bioaccumulation of UV-absorbing compounds in the gonads and larvae of C. altimanus, and to a lesser extent in C. angulatus, might have contributed for counteracting the impact of UV-B. However, most of the resilience to UV-B observed with the increase in temperature might be due to an increase in metabolic activity caused by a repair mechanism mediated by enzymes. PMID:20559492

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  6. Characterization of the adaptive response of grapevine (cv. Tempranillo) to UV-B radiation under water deficit conditions.

    PubMed

    Martínez-Lüscher, J; Morales, F; Delrot, S; Sánchez-Díaz, M; Gomès, E; Aguirreolea, J; Pascual, I

    2015-03-01

    This work aims to characterize the physiological response of grapevine (Vitis vinifera L.) cv. Tempranillo to UV-B radiation under water deficit conditions. Grapevine fruit-bearing cuttings were exposed to three levels of supplemental biologically effective UV-B radiation (0, 5.98 and 9.66kJm(-2)day(-1)) and two water regimes (well watered and water deficit), in a factorial design, from fruit-set to maturity under glasshouse-controlled conditions. UV-B induced a transient decrease in net photosynthesis (Anet), actual and maximum potential efficiency of photosystem II, particularly on well watered plants. Methanol extractable UV-B absorbing compounds (MEUVAC) concentration and superoxide dismutase activity increased with UV-B. Water deficit effected decrease in Anet and stomatal conductance, and did not change non-photochemical quenching and the de-epoxidation state of xanthophylls, dark respiration and photorespiration being alternative ways to dissipate the excess of energy. Little interactive effects between UV-B and drought were detected on photosynthesis performance, where the impact of UV-B was overshadowed by the effects of water deficit. Grape berry ripening was strongly delayed when UV-B and water deficit were applied in combination. In summary, deficit irrigation did not modify the adaptive response of grapevine to UV-B, through the accumulation of MEUVAC. However, combined treatments caused additive effects on berry ripening. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. Sulfur and Sulfuric Acid Microphysics in the Venus Atmosphere: Implications for the Unknown UV Absorber

    NASA Astrophysics Data System (ADS)

    Gao, P.; Carlson, R. W.; Robinson, T. D.; Crisp, D.; Lyons, J. R.; Yung, Y. L.

    2016-12-01

    A mystery that has continued to plague our sister planet, Venus, for nearly a century is the nature of the brightness contrasts observed crisscrossing its disk in near-ultraviolet wavelength images. These contrasts - specifically the dark regions - have been attributed to the actions of an unknown UV absorber, knowing the identity of which is integral to understanding the Venus atmosphere due to the high rates of mesospheric heating attributed to the absorption of solar UV. One possible candidate for the UV absorber is polysulfur, which form from polymerization of elemental sulfur arising from SO2 photolysis at the Venus cloud tops under low O2 conditions. In this work we investigate the microphysics of condensed polysulfur and its interaction with the sulfuric acid clouds. We consider the "gumdrop model", where sulfur is allowed to condense onto sulfuric acid cloud particles. We explore the possibility that S2 vapor may condense faster than its loss to gas phase reactions that produce higher allotropes, leading to solid state polymerization to S8. This process may explain the ephemeral and variable nature of the UV absorption.

  8. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Hodgson, Ed; Izenson, Mike; Chan, Weibo; Bue, Grant C.

    2012-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  9. UV RADIATION EFFECTS ON MICROBES AND MICROBIAL PROCESSES

    EPA Science Inventory

    The ultraviolet (UV) region of solar radiation is defined as wavelengths in the range of 200 to 400 nm. In contrast to visible radiation (400 - 800 nm), which has a well-defined role as the energy source for most of the Earth's primary production, the effects of UV radiation on b...

  10. Preparation of O/I1-type Emulsions and S/I1-type Dispersions Encapsulating UV-Absorbing Agents.

    PubMed

    Aramaki, Kenji; Kimura, Minami; Masuda, Kazuki

    2015-01-01

    Oil-in-cubic phase (O/I1) emulsions encapsulating the cosmetic UV absorbing agents 2-ethylhexyl 4-methoxycinnamate (EHMC), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (octocrylene, OCR) and 1-(4-tertbutylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione (Avobenzone, TBMP) were prepared by vortex mixing accompanied by a heating-cooling process. A ternary phase diagram in a water/C12EO25/EHMC system at 25°C was constructed and the two-phase equilibrium of an oil phase and an I1 phase, which is necessary to prepare the O/I1-type emulsions, was confirmed. Also, the melting of the I1 phase into a fluid micellar solution phase was confirmed, allowing emulsification by a heating-cooling process. The O/I1-type emulsions were formulated in the ternary system as well as a quaternary system. The four-component system contained an additional cosolvent, isopropyl myristate (IPM). The use of the cosolvent allows the use of reduced amounts of EHMC, which is desirable because EHMC can cause temporary skin irritation. Formulation of the O/I1-type emulsions with other UV absorbing agents (OCR and TBMP) was also possible using the same emulsification method. When IPM was changed to tripalmitin, which has a melting point greater than room temperature, a solid-oil dispersion in I1 phase was formed. We have termed this a "solidin-cubic phase (S/I1) type dispersion". These novel emulsions have not been reported previously. The UV absorbability of the O/I1-type emulsions and S/I1-type dispersions that encapsulate the UV absorbing agents was confirmed by measurement of UV absorption spectra.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Performance of a Multifunctional Space Evaporator- Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Bue, Grant; Quinn, Gregory

    2013-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 sq ft prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable heat rejection from the LCAR.

  13. Temporal variation in epidermal flavonoids due to altered solar UV radiation is moderated by the leaf position in Betula pendula.

    PubMed

    Morales, Luis O; Tegelberg, Riitta; Brosché, Mikael; Lindfors, Anders; Siipola, Sari; Aphalo, Pedro J

    2011-11-01

    The physiological mechanisms controlling plant responses to dynamic changes in ambient solar ultraviolet (UV) radiation are not fully understood: this information is important to further comprehend plant adaptation to their natural habitats. We used the fluorimeter Dualex to estimate in vivo the epidermal flavonoid contents by measuring epidermal UV absorbance (A(375) ) in Betula pendula Roth (silver birch) leaves of different ages under altered UV. Seedlings were grown in a greenhouse for 15 days without UV and transferred outdoors under three UV treatments (UV-0, UV-A and UV-A+B) created by three types of plastic film. After 7 and 13 days, Dualex measurements were taken at adaxial and abaxial epidermis of the first three leaves (L1, L2 and L3) of the seedlings. After 14 days, some of the seedlings were reciprocally swapped amongst the treatments to study the accumulation of epidermal flavonoids in the youngest unfolded leaves (L3) during leaf expansion under changing solar UV environments. A(375) of the leaves responded differently to the UV treatment depending on their position. UV-B increased the A(375) in the leaves independently of leaf position. L3 quickly adjusted A(375) in their epidermis according to the UV they received and these adjustments were affected by previous UV exposure. The initial absence of UV-A+B or UV-A, followed by exposure to UV-A+B, particularly enhanced leaf A(375) . Silver birch leaves modulate their protective pigments in response to changes in the UV environment during their expansion, and their previous UV exposure history affects the epidermal-absorbance achieved during later UV exposure. Copyright © Physiologia Plantarum 2011.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    1988-12-01

    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.

  15. Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers

    NASA Astrophysics Data System (ADS)

    Mazzillo, M.; Sciuto, A.; Mannino, G.; Renna, L.; Costa, N.; Badalà, P.

    2016-10-01

    Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. The sun is our primary natural source of UV radiation. The strength of the sun's ultraviolet radiation is expressed as Solar UV Index (UVI). UV-A (320-400 nm) and UV-B (290-320 nm) rays mostly contribute to UVI. UV-B is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA. Also overexposure to UV-A rays, although these are less energetic than UV-B photons, has been associated with toughening of the skin, suppression of the immune system, and cataract formation. The use of preventive measures to decrease sunlight UV radiation absorption is fundamental to reduce acute and irreversible health diseases to skin, eyes and immune system. In this perspective UV sensors able to monitor in a monolithic and compact chip the UV Index and relative UV-A and UV-B components of solar spectrum can play a relevant role for prevention, especially in view of the integration of these detectors in close at hand portable devices. Here we present the preliminary results obtained on our UV-A sensor technology based on the use of hydrogenated Silicon Nitride (SiN:H) thin passivating layers deposited on the surface of thin continuous metal film Ni2Si/4H-SiC Schottky detectors, already used for UV-Index monitoring. The first UV-A detector prototypes exhibit a very low leakage current density of about 0.2 pA/mm2 and a peak responsivity value of 0.027 A/W at 330 nm, both measured at 0V bias.

  16. Photosynthetic characteristics and mycosporine-like amino acids under UV radiation: a competitive advantage of Mastocarpus stellatus over Chondrus crispus at the Helgoland shoreline?

    NASA Astrophysics Data System (ADS)

    Bischof, K.; Kräbs, G.; Hanelt, D.; Wiencke, C.

    2000-05-01

    Chondrus crispus and Mastocarpus stellatus both inhabit the intertidal and upper sublittoral zone of Helgoland, but with C. crispus generally taking a lower position. Measurements of chlorophyll fluorescence, activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), and content and composition of UV absorbing mycosporine-like amino acids (MAAs) were conducted in the laboratory, to test whether susceptibility to UV radiation may play a role in the vertical distribution of these two species. Effective and maximal quantum yield of photochemistry as well as maximal electron transport rate (ETRmax) in C. crispus were more strongly affected by UV-B radiation than in M. stellatus. In both species, no negative effects of the respective radiation conditions were found on total activity of RubisCO. Total MAA content in M. stellatus was up to 6-fold higher than in C. crispus and the composition of MAAs in the two species was different. The results indicate that, among others, UV-B sensitivity may be a factor restricting C. crispus to the lower intertidal and upper sublittoral zone, whereas M. stellatus is better adapted to UV radiation and is therefore more competitive in the upper intertidal zone.

  17. UV Radiation and the Skin

    PubMed Central

    D’Orazio, John; Jarrett, Stuart; Amaro-Ortiz, Alexandra; Scott, Timothy

    2013-01-01

    UV radiation (UV) is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R) gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance. PMID:23749111

  18. UV radiation and the skin.

    PubMed

    D'Orazio, John; Jarrett, Stuart; Amaro-Ortiz, Alexandra; Scott, Timothy

    2013-06-07

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

  19. Impacts of long-term enhanced UV-B radiation on bryophytes in two sub-Arctic heathland sites of contrasting water availability.

    PubMed

    Arróniz-Crespo, M; Gwynn-Jones, D; Callaghan, T V; Núñez-Olivera, E; Martínez-Abaigar, J; Horton, P; Phoenix, G K

    2011-09-01

    Anthropogenic depletion of stratospheric ozone in Arctic latitudes has resulted in an increase of ultraviolet-B radiation (UV-B) reaching the biosphere. UV-B exposure is known to reduce above-ground biomass and plant height, to increase DNA damage and cause accumulation of UV-absorbing compounds in polar plants. However, many studies on Arctic mosses tended to be inconclusive. The importance of different water availability in influencing UV-B impacts on lower plants in the Arctic has been poorly explored and might partially explain the observed wide variation of responses, given the importance of water in controlling bryophyte physiology. This study aimed to assess the long-term responses of three common sub-Arctic bryophytes to enhanced UV-B radiation (+UV-B) and to elucidate the influence of water supply on those responses. Responses of three sub-Arctic bryophytes (the mosses Hylocomium splendens and Polytrichum commune and the liverwort Barbilophozia lycopodioides) to +UV-B for 15 and 13 years were studied in two field experiments using lamps for UV-B enhancement with identical design and located in neighbouring areas with contrasting water availability (naturally mesic and drier sites). Responses evaluated included bryophyte abundance, growth, sporophyte production and sclerophylly; cellular protection by accumulation of UV-absorbing compounds, β-carotene, xanthophylls and development of non-photochemical quenching (NPQ); and impacts on photosynthesis performance by maximum quantum yield (F(v) /F(m)) and electron transport rate (ETR) through photosystem II (PSII) and chlorophyll concentrations. Responses were species specific: H. splendens responded most to +UV-B, with reduction in both annual growth (-22 %) and sporophyte production (-44 %), together with increased β-carotene, violaxanthin, total chlorophyll and NPQ, and decreased zeaxanthin and de-epoxidation of the xanthophyll cycle pool (DES). Barbilophozia lycopodioides responded less to +UV-B, showing

  20. The enhancement of biological ocular UV radiation on beaches compared to the radiation on grass.

    PubMed

    Liu, Guang-Cong; Wang, Fang; Gao, Yan-Yan; Yang, Zheng; Hu, Li-Wen; Gao, Qian; Ri, Jun-Chol; Liu, Yang

    2014-12-01

    The influence of albedo on ocular UV exposure has seldom been reported. This paper aimed to explore the enhancement effect on measured ocular UV radiation due to a sand surface compared to measured ocular UV radiation due to a grass surface. We measured ambient and ocular UV radiation over the beach and grass surface in Sanya City of China (18.4°N, 109.7°E). The experimental apparatus was composed of a manikin and a dual-detector spectrometer. Integration of both UVA and UVB radiation was used to denote UV radiation. Then biologically effective ocular UVB radiation (UVBE) and the ratios of UVBE of two surfaces were calculated. Maximum of ocular UV radiation versus time over the two surfaces is bimodal. UVBE on the beach is significantly larger than UVBE on the sand, and UVBE peaked at different solar elevation angle (SEA) over the two surfaces (about 53° and 40° on the beach and grass, respectively, according to Bayesian regression). The maximum of ocular UVBE ratios is greater than two, which peaked SEA was about 50°. One hour's cumulative radiation under sunny weather exceeds thresholds for photokeratitis, conjunctivitis and lens damage. Higher albedo significantly increased biological ocular UV radiation. Tourists on tropical beaches should take protective measures and avoid facing the sun directly, especially when SEA is around 50°. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Ozonation of the oxybenzone, octinoxate, and octocrylene UV-filters: Reaction kinetics, absorbance characteristics, and transformation products.

    PubMed

    Hopkins, Zachary R; Snowberger, Sebastian; Blaney, Lee

    2017-09-15

    UV-filters (UVFs) are active ingredients in personal care products that protect skin from exposure to UV light. Environmentally-relevant concentrations of UVFs have recently been linked to toxicity in aquatic organisms, necessitating research into improved UVF removal in water/wastewater treatment. Here, we investigated ozonation of the three most commonly employed UVFs: octinoxate (OMC), octocrylene (OC), and oxybenzone (OXY). Specific second-order rate constants for UVF reaction with ozone were identified as follows: OMC, 5.25×10 4 M -1 s -1 ; OC, 1.58M -1 s -1 ; OXY (neutral), 3.80×10 2 M -1 s -1 ; and, OXY (anion), 1.51×10 6 M -1 s -1 . These kinetic parameters indicated that OMC and OXY undergo significant (2-log or greater) transformation for typical ozone exposures in disinfection processes; however, minimal oxidation is expected for OC. UV absorbance mapping was employed to characterize the loss of UVF activity (i.e., absorbance across the UV-A, UV-B, and UV-C ranges) during ozonation. These 4-dimensional maps also confirmed ozone attack mechanisms, namely reaction at phenolate (OXY) and olefin (OMC, OC) groups. Primary transformation products from these reactions were identified for all three UVFs of concern. For OC and OXY, the benzophenone structure is conserved, suggesting that transformation products retain toxicity concerns. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    1999-04-01

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

  4. Forecasting of UV-Vis absorbance time series using artificial neural networks combined with principal component analysis.

    PubMed

    Plazas-Nossa, Leonardo; Hofer, Thomas; Gruber, Günter; Torres, Andres

    2017-02-01

    This work proposes a methodology for the forecasting of online water quality data provided by UV-Vis spectrometry. Therefore, a combination of principal component analysis (PCA) to reduce the dimensionality of a data set and artificial neural networks (ANNs) for forecasting purposes was used. The results obtained were compared with those obtained by using discrete Fourier transform (DFT). The proposed methodology was applied to four absorbance time series data sets composed by a total number of 5705 UV-Vis spectra. Absolute percentage errors obtained by applying the proposed PCA/ANN methodology vary between 10% and 13% for all four study sites. In general terms, the results obtained were hardly generalizable, as they appeared to be highly dependent on specific dynamics of the water system; however, some trends can be outlined. PCA/ANN methodology gives better results than PCA/DFT forecasting procedure by using a specific spectra range for the following conditions: (i) for Salitre wastewater treatment plant (WWTP) (first hour) and Graz West R05 (first 18 min), from the last part of UV range to all visible range; (ii) for Gibraltar pumping station (first 6 min) for all UV-Vis absorbance spectra; and (iii) for San Fernando WWTP (first 24 min) for all of UV range to middle part of visible range.

  5. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  6. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and adaptability to highly variable thermal environments. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flightlike, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  7. UV and ionizing radiations induced DNA damage, differences and similarities

    NASA Astrophysics Data System (ADS)

    Ravanat, Jean-Luc; Douki, Thierry

    2016-11-01

    Both UV and ionizing radiations damage DNA. Two main mechanisms, so-called direct and indirect pathways, are involved in the degradation of DNA induced by ionizing radiations. The direct effect of radiation corresponds to direct ionization of DNA (one electron ejection) whereas indirect effects are produced by reactive oxygen species generated through water radiolysis, including the highly reactive hydroxyl radicals, which damage DNA. UV (and visible) light damages DNA by again two distinct mechanisms. UVC and to a lesser extend UVB photons are directly absorbed by DNA bases, generating their excited states that are at the origin of the formation of pyrimidine dimers. UVA (and visible) light by interaction with endogenous or exogenous photosensitizers induce the formation of DNA damage through photosensitization reactions. The excited photosensitizer is able to induce either a one-electron oxidation of DNA (type I) or to produce singlet oxygen (type II) that reacts with DNA. In addition, through an energy transfer from the excited photosensitizer to DNA bases (sometime called type III mechanism) formation of pyrimidine dimers could be produced. Interestingly it has been shown recently that pyrimidine dimers are also produced by direct absorption of UVA light by DNA, even if absorption of DNA bases at these wavelengths is very low. It should be stressed that some excited photosensitizers (such as psoralens) could add directly to DNA bases to generate adducts. The review will described the differences and similarities in terms of damage formation (structure and mechanisms) between these two physical genotoxic agents.

  8. Development of UV-B screening compounds in response to variation in ambient levels of UV-B radiation

    NASA Astrophysics Data System (ADS)

    Sullivan, Joe H.; Xu, Chenping; Gao, Wei; Slusser, James R.

    2005-08-01

    The induction of UV-B screening compounds in response to exposure to UV-B radiation is a commonly reported response and is generally considered to be an adaptive response of plants for protection from UVinduced damage. However, a number of questions remain to be answered including the importance of qualitative and localization differences among species in providing protection, indirect consequences of changes in leaf secondary chemistry on ecological processes and the dose response of metabolite accumulation. In this study we utilized UV monitoring data provided on site by the USDA UV-B Monitoring and Research Program to monitor the changes in UV-screening compounds in soybeans under a range of UV-B levels due to natural variation in ambient UV-B radiation. Soybean cultivars Essex, Clark and Clark-magenta, an isoline of Clark that produces minimal levels of flavonols, were grown beneath shelters covered either with polyester to block most UV-B radiation or teflon which is nearly transparent in the UV range and harvested at regular intervals for pigment and protein analysis. Daily levels of weighted UV-B varied from <1 to >7 kJ m-2. Increases in UV-screening compounds showed a positive dose response to UV-B radiation in all cultivars with Essex showing the steepest dose response. UV-A also induced screening compounds in all species The hydroxycinnimates of the magenta isoline showed a steep dose response to UV-A and a rather constant (non dose specific) but small additional increment in response to UV-B. The Clark isoline, which produced primarily the flavonol quercetin, showed a dose response to UV-B intermediate between that of Clark-magenta and Essex. All three cultivars show similar tolerance to UV-B in field conditions indicating that UV-induced pigment production is adequate to protect them from excessive UV-B damage.

  9. UV-B effect on constituents of Azolla caroliniana.

    PubMed

    Ibrahim, Mohamed M; Mostafa, Eazaz M

    2007-01-01

    Changes in growth and ultrastructure of Azolla caroliniana in response to elevated UV-B radiation were investigated. Exposure of plants to UV-B radiation for 1, 8, 16, 24 and 48 h exhibited a significant decrease in biomass and relative growth rate. This decrease resulted in an increase in doubling time over the control. Also, Chl a and b contents were significantly decreased especially after 16 h. The reduction was accompanied by a decrease in 5-aminolaevulinic acid content (precursor of chlorophyll). On the other hand, contents of carotenoid and UV-absorbing phenolic compounds (flavonoids and anthocyanins) were increased.

  10. Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

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

    NASA Astrophysics Data System (ADS)

    Feister, U.; Junk, J.; Woldt, M.

    2008-01-01

    Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980-1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

  12. Study of UV radiation dose received by the Spanish population.

    PubMed

    Gurrea, Gonzalo; Cañada, Javier

    2007-01-01

    Excess exposure to UV radiation can affect our health by causing sunburn, skin cancer, etc. It is therefore useful to determine the UV dosage received by people as a way of protecting them from the possible negative effects that this kind of radiation can cause. In this work, the personal outdoor percentage, which shows the time spent in outdoor activities, as well as personal UV doses, has been calculated by means of global UV radiation on a horizontal plane. A database of average daily UVB radiation on the horizontal plane given by the National Institute of Meteorology has been used. In this work we evaluate the standard erythema dose of the Spanish population throughout the year.

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    PubMed

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

    1987-06-01

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

  17. UV filters for lighting of plants

    NASA Astrophysics Data System (ADS)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H. K.; Payer, H. D.

    1994-03-01

    The wavelength dependent interaction of biological systems with radiation is commonly described by appropriate action spectra. Particularly effective plant responses are obtained for ultraviolet (UV) radiation. Excess shortwave UV-B radiation will induce genetic defects and plant damage. Besides the ecological discussion of the deleterious effects of the excess UV radiation there is increasing interest in horticultural applications of this spectral region. Several metabolic pathways leading to valuable secondary plant products like colors, odors, taste, or resulting in mechanical strength and vitality are triggered by UV radiation. Thus, in ecologically as well as in economically oriented experiments the exact generation and knowledge of the spectral irradiance, particularly near the UV absorption edge, is essential. The ideal filter 'material' to control the UV absorption edge would be ozone itself. However, due to problems in controlling the toxic and chemically aggressive, instable gas, only rather 'small ozone filters' have been realized so far. In artificial plant lighting conventional solid filter materials such as glass sheets and plastic foils (celluloseacetate or cellulosetriacetate) which can be easily handled have been used to absorb the UV-C and the excess shortwave UV-B radiation of the lamp emissions. Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The aging of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In

  18. UV filters for lighting of plants

    NASA Technical Reports Server (NTRS)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H. K.; Payer, H. D.

    1994-01-01

    The wavelength dependent interaction of biological systems with radiation is commonly described by appropriate action spectra. Particularly effective plant responses are obtained for ultraviolet (UV) radiation. Excess shortwave UV-B radiation will induce genetic defects and plant damage. Besides the ecological discussion of the deleterious effects of the excess UV radiation there is increasing interest in horticultural applications of this spectral region. Several metabolic pathways leading to valuable secondary plant products like colors, odors, taste, or resulting in mechanical strength and vitality are triggered by UV radiation. Thus, in ecologically as well as in economically oriented experiments the exact generation and knowledge of the spectral irradiance, particularly near the UV absorption edge, is essential. The ideal filter 'material' to control the UV absorption edge would be ozone itself. However, due to problems in controlling the toxic and chemically aggressive, instable gas, only rather 'small ozone filters' have been realized so far. In artificial plant lighting conventional solid filter materials such as glass sheets and plastic foils (celluloseacetate or cellulosetriacetate) which can be easily handled have been used to absorb the UV-C and the excess shortwave UV-B radiation of the lamp emissions. Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The aging of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In

  19. Anti-Inflammation Activities of Mycosporine-Like Amino Acids (MAAs) in Response to UV Radiation Suggest Potential Anti-Skin Aging Activity

    PubMed Central

    Suh, Sung-Suk; Hwang, Jinik; Park, Mirye; Seo, Hyo Hyun; Kim, Hyoung-Shik; Lee, Jeong Hun; Moh, Sang Hyun; Lee, Taek-Kyun

    2014-01-01

    Certain photosynthetic marine organisms have evolved mechanisms to counteract UV-radiation by synthesizing UV-absorbing compounds, such as mycosporine-like amino acids (MAAs). In this study, MAAs were separated from the extracts of marine green alga Chlamydomonas hedleyi using HPLC and were identified as porphyra-334, shinorine, and mycosporine-glycine (mycosporine-Gly), based on their retention times and maximum absorption wavelengths. Furthermore, their structures were confirmed by triple quadrupole MS/MS. Their roles as UV-absorbing compounds were investigated in the human fibroblast cell line HaCaT by analyzing the expression levels of genes associated with antioxidant activity, inflammation, and skin aging in response to UV irradiation. The mycosporine-Gly extract, but not the other MAAs, had strong antioxidant activity in the 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Furthermore, treatment with mycosporine-Gly resulted in a significant decrease in COX-2 mRNA levels, which are typically increased in response to inflammation in the skin, in a concentration-dependent manner. Additionally, in the presence of MAAs, the UV-suppressed genes, procollagen C proteinase enhancer (PCOLCE) and elastin, which are related to skin aging, had increased expression levels equal to those in UV-mock treated cells. Interestingly, the increased expression of involucrin after UV exposure was suppressed by treatment with the MAAs mycosporine-Gly and shinorine, but not porphyra-334. This is the first report investigating the biological activities of microalgae-derived MAAs in human cells. PMID:25317535

  20. Anti-inflammation activities of mycosporine-like amino acids (MAAs) in response to UV radiation suggest potential anti-skin aging activity.

    PubMed

    Suh, Sung-Suk; Hwang, Jinik; Park, Mirye; Seo, Hyo Hyun; Kim, Hyoung-Shik; Lee, Jeong Hun; Moh, Sang Hyun; Lee, Taek-Kyun

    2014-10-14

    Certain photosynthetic marine organisms have evolved mechanisms to counteract UV-radiation by synthesizing UV-absorbing compounds, such as mycosporine-like amino acids (MAAs). In this study, MAAs were separated from the extracts of marine green alga Chlamydomonas hedleyi using HPLC and were identified as porphyra-334, shinorine, and mycosporine-glycine (mycosporine-Gly), based on their retention times and maximum absorption wavelengths. Furthermore, their structures were confirmed by triple quadrupole MS/MS. Their roles as UV-absorbing compounds were investigated in the human fibroblast cell line HaCaT by analyzing the expression levels of genes associated with antioxidant activity, inflammation, and skin aging in response to UV irradiation. The mycosporine-Gly extract, but not the other MAAs, had strong antioxidant activity in the 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Furthermore, treatment with mycosporine-Gly resulted in a significant decrease in COX-2 mRNA levels, which are typically increased in response to inflammation in the skin, in a concentration-dependent manner. Additionally, in the presence of MAAs, the UV-suppressed genes, procollagen C proteinase enhancer (PCOLCE) and elastin, which are related to skin aging, had increased expression levels equal to those in UV-mock treated cells. Interestingly, the increased expression of involucrin after UV exposure was suppressed by treatment with the MAAs mycosporine-Gly and shinorine, but not porphyra-334. This is the first report investigating the biological activities of microalgae-derived MAAs in human cells.

  1. MicroRNAs in Skin Response to UV Radiation

    PubMed Central

    Syed, Deeba N.; Khan, Mohammad Imran; Shabbir, Maria; Mukhtar, Hasan

    2014-01-01

    Solar ultraviolet (UV) radiation, an ubiquitous environmental carcinogen, is classified depending on the wave-length, into three regions; short-wave UVC (200–280 nm), mid-wave UVB (280–320 nm), and long-wave UVA (320–400 nm). The human skin, constantly exposed to UV radiation, particularly the UVB and UVA components, is vulnerable to its various deleterious effects such as erythema, photoaging, immunosuppression and cancer. To counteract these and for the maintenance of genomic integrity, cells have developed several protective mechanisms including DNA repair, cell-cycle arrest and apoptosis. The network of damage sensors, signal transducers, mediators, and various effector proteins is regulated through changes in gene expression. MicroRNAs (miRNAs), a group of small non-coding RNAs, act as post-transcriptional regulators through binding to complementary sequences in the 3′-untranslated region of their target genes, resulting in either translational repression or target degradation. Recent studies show that miRNAs add an additional layer of complexity to the intricately controlled cellular responses to UV radiation. This review summarizes our current knowledge of the role of miRNAs in the regulation of the human skin response upon exposure to UV radiation. PMID:23834148

  2. Temporal-spatial variation of DOC concentration, UV absorbance and the flux estimation in the Lower Dagu River, China

    NASA Astrophysics Data System (ADS)

    Xi, Min; Kong, Fanlong; Li, Yue; Kong, Fanting

    2017-12-01

    Dissolved organic carbon (DOC) is an important component for both carbon cycle and energy balance. The concentration, UV absorbance, and export flux of DOC in the natural environment dominate many important transport processes. To better understand the temporal and spatial variation of DOC, 7 sites along the Lower Dagu River were chosen to conduct a comprehensive measurement from March 2013 to February 2014. Specifically, water samples were collected from the Lower Dagu River between the 26th and 29th of every month during the experimental period. The DOC concentration (CDOC) and UV absorbance were analyzed using a total organic carbon analyzer and the ultraviolet-visible absorption spectrum, and the DOC export flux was estimated with a simple empirical model. The results showed that the CDOC of the Lower Dagu River varied from 1.32 to 12.56 mg/L, consistent with global rivers. The CDOC and UV absorbance showed significant spatial variation in the Dagu River during the experiential period because of the upstream natural processes and human activities in the watershed. The spatial variation is mainly due to dam or reservoir constructions, riverside ecological environment changes, and non-point source or wastewater discharge. The seasonal variation of CDOC was mainly related to the source of water DOC, river runoff, and temperature, and the UV absorbance and humification degree of DOC had no obvious differences among months ( P<0.05). UV absorbance was applied to test the CDOC in Lower Dagu River using wave lengths of 254 and 280 nm. The results revealed that the annual DOC export flux varied from 1.6 to 3.76 × 105 g C/km2/yr in a complete hydrological year, significantly lower than the global average. It is worth mentioning that the DOC export flux was mainly concentrated in summer (˜90% of all-year flux in July and August), since the runoff in the Dagu River took place frequently in summer. These observations implied environment change could bring the temporal

  3. Arsenic oxidation by UV radiation combined with hydrogen peroxide.

    PubMed

    Sorlini, S; Gialdini, F; Stefan, M

    2010-01-01

    Arsenic is a widespread contaminant in the environment around the world. The most abundant species of arsenic in groundwater are arsenite [As(III)] and arsenate [As(V)]. Several arsenic removal processes can reach good removal yields only if arsenic is present as As(V). For this reason it is often necessary to proceed with a preliminary oxidation of As(III) to As(V) prior to the removal technology. Several studies have focused on arsenic oxidation with conventional reagents and advanced oxidation processes. In the present study the arsenic oxidation was evaluated using hydrogen peroxide, UV radiation and their combination in distilled and in real groundwater samples. Hydrogen peroxide and UV radiation alone are not effective at the arsenic oxidation. Good arsenic oxidation yields can be reached in presence of hydrogen peroxide combined with a high UV radiation dose (2,000 mJ/cm(2)). The quantum efficiencies for As(III) oxidation were calculated for both the UV photolysis and the UV/H(2)O(2) processes.

  4. Antioxidant responses of damiana (Turnera diffusa Willd) to exposure to artificial ultraviolet (UV) radiation in an in vitro model; part ii; UV-B radiation.

    PubMed

    Soriano-Melgar, Lluvia de Abril Alexandra; Alcaraz-Meléndez, Lilia; Méndez-Rodríguez, Lía C; Puente, María Esther; Rivera-Cabrera, Fernando; Zenteno-Savín, Tania

    2014-05-01

    Ultraviolet type B (UV-B) radiation effects on medicinal plants have been recently investigated in the context of climate change, but the modifications generated by UV-B radiation might be used to increase the content of antioxidants, including phenolic compounds. To generate information on the effect of exposure to artificial UV-B radiation at different highdoses in the antioxidant content of damiana plants in an in vitro model. Damiana plantlets (tissue cultures in Murashige- Skoog medium) were irradiated with artificial UV-B at 3 different doses (1) 0.5 ± 0.1 mW cm-2 (high) for 2 h daily, (2) 1 ± 0,1 mW cm-2 (severe) for 2 h daily, or (3) 1 ± 0.1 mW cm-2 for 4 h daily during 3 weeks. The concentration of photosynthetic pigments (chlorophylls a and b, carotenoids), vitamins (C and E) and total phenolic compounds, the enzymatic activity of superoxide dismutase (SOD, EC 1.15.1.1) and total peroxidases (POX, EC 1.11.1), as well as total antioxidant capacity and lipid peroxidation levels were quantified to assess the effect of high artificial UV-B radiation in the antioxidant content of in vitro damiana plants. Severe and high doses of artificial UV-B radiation modified the antioxidant content by increasing the content of vitamin C and decreased the phenolic compound content, as well as modified the oxidative damage of damiana plants in an in vitro model. UV-B radiation modified the antioxidant content in damiana plants in an in vitro model, depending on the intensity and duration of the exposure. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  5. UV radiation and skin cancer in Norway.

    PubMed

    Medhaug, I; Olseth, J A; Reuder, J

    2009-09-04

    A distinct increase in skin cancer incidences is observed since the registration started in Norway in the 1950s. As UV radiation is assumed to be the main risk factor for skin cancer, hourly values of the UV irradiance were reconstructed for the period 1957-2005 for 17 of the Norwegian counties (58-70 degrees N). For reconstruction, a radiation transfer model is run with total ozone amount and cloud information as meteorological input. Reconstructed hourly erythemally weighted UV irradiances for about 5 years are compared to measurements at four stations, two stations representing the north-south extension of Norway, and two stations at about 60 degrees N representing the eastern inland - Western coastal contrasts. The agreement between reconstructed and measured UV varies between 0% for the northernmost site to 10-15% overestimation for the other locations. For clear sky, a reasonable agreement between reconstructed and measured data was found for all stations, while for overcast, an overestimation of 10-20% was found for all but the northernmost station. Both the cancer incidences and the reconstructed UV values have a distinct north-south increase. The UV increase towards south is mostly due to increasing solar elevation. The west to east increase is much smaller, and differences in UV are due to differences in both cloud optical thickness and total cloud amount. One additional outcome from this work is that long-term UV-data are reconstructed for Norway, data that can be used in further biological and medical studies related to UV effects.

  6. The Photostabilizing Effect of Grape Seed Extract on Three Common Sunscreen Absorbers.

    PubMed

    Martincigh, Bice S; Ollengo, Moses A

    2016-11-01

    The photostabilizing ability of grape seed extract on three common sunscreen absorbers, 2-ethylhexyl-p-methoxycinnamate (EHMC), benzophenone-3 (BP3) and tert-butylmethoxy dibenzoylmethane (BMDBM), was investigated. Samples were exposed to simulated solar radiation and monitored by spectrophotometric and chromatographic methods. The chemical composition of the grape seed extract was determined by GC-MS and HPLC-MS, and the major secondary metabolites were found to be epicatechin and catechin. Exposure of the extract to UV radiation increased the UV absorption capacity of the extract. All sunscreens showed an improved photostability in the extract. The inherent photo-instability of BMDBM when exposed to UV radiation was almost eliminated in the presence of grape seed extract. A mixture of all three sunscreens in the extract showed very high photostability and a red shift covering the entire UVB and UVA regions, thereby improving the broad-spectrum protection. The incorporation of grape seed extract in sunscreen and other cosmetic formulations for topical application boosts photoprotection by stabilizing the UV filters and enhancing broad-spectrum coverage. This in turn helps in reducing the amounts of absorbers and other additives incorporated in a sunscreen product and consequently lowers the risk of an unprecedented buildup of photoproducts whose toxicities are currently unknown. © 2016 The American Society of Photobiology.

  7. UV radiation induces CXCL5 expression in human skin.

    PubMed

    Reichert, Olga; Kolbe, Ludger; Terstegen, Lara; Staeb, Franz; Wenck, Horst; Schmelz, Martin; Genth, Harald; Kaever, Volkhard; Roggenkamp, Dennis; Neufang, Gitta

    2015-04-01

    CXCL5 has recently been identified as a mediator of UVB-induced pain in rodents. To compare and to extend previous knowledge of cutaneous CXCL5 regulation, we performed a comprehensive study on the effects of UV radiation on CXCL5 regulation in human skin. Our results show a dose-dependent increase in CXCL5 protein in human skin after UV radiation. CXCL5 can be released by different cell types in the skin. We presumed that, in addition to immune cells, non-immune skin cells also contribute to UV-induced increase in CXCL5 protein. Analysis of monocultured dermal fibroblasts and keratinocytes revealed that only fibroblasts but not keratinocytes displayed up regulated CXCL5 levels after UV stimulation. Whereas UV treatment of human skin equivalents, induced epidermal CXCL5 mRNA and protein expression. Up regulation of epidermal CXCL5 was independent of keratinocyte differentiation and keratinocyte-keratinocyte interactions in epidermal layers. Our findings provide first evidence on the release of CXCL5 in UV-radiated human skin and the essential role of fibroblast-keratinocyte interaction in the regulation of epidermal CXCL5. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Glory on Venus and selection among the unknown UV absorbers

    NASA Astrophysics Data System (ADS)

    Petrova, Elena V.

    2018-05-01

    The comparison of the phase profiles of glories observed on the cloud top of Venus by the Venus Monitoring Camera (Venus Express) and the light-scattering characteristics of sulfuric acid droplets, containing admixtures with a high refractive index, makes it easier to choose between some candidates for the so-called unknown UV absorber in the Venus clouds. Since among the candidates there are materials wetted and not wetted by sulfuric acid, we analyze whether small submicron particles adhered to or embedded into the 1-μm H2SO4 droplets may actually change the glory pattern normally produced by homogeneous spherical particles and what the conditions are, under which the composite particles formed in heterogeneous nucleation may still produce a glory feature. We have found that one of the most frequently considered candidates, sulfur, can hardly be responsible for the contrasts observed at 0.365 μm on the upper clouds, since it is not wetted by sulfuric acid and submicron sulfur particles, serving as condensation nuclei for sulfuric acid, can only adhere to the H2SO4 droplets rather than be enveloped by them. Such droplets decorated by sulfur blobs substantially distort the glory feature characteristic of the scattering by spherical particles or even smooth it at all, while a glory pattern is practically always seen in the images of Venus taken at small phase angles. At the same time, the grains of the other UV absorbers that can be embedded in H2SO4 droplets, e.g., the widely discussed ferric chloride, pose no problem in terms of interpretation of the observations of glory.

  9. Spectral estimators of absorbed photosynthetically active radiation in corn canopies

    NASA Technical Reports Server (NTRS)

    Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

    1985-01-01

    Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a Landsat MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95 percent of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50 percent of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73 percent of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

  10. Spectral estimators of absorbed photosynthetically active radiation in corn canopies

    NASA Technical Reports Server (NTRS)

    Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

    1984-01-01

    Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a LANDSAT MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95% of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50% of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73% of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

  11. On the radiative effects of light-absorbing impurities on snowpack evolution

    NASA Astrophysics Data System (ADS)

    Dumont, M.; Tuzet, F.; Lafaysse, M.; Arnaud, L.; Picard, G.; Lejeune, Y.; Lamare, M.; Morin, S.; Voisin, D.; Di Mauro, B.

    2017-12-01

    The presence of light absorbing impurities in snow strongly decreases snow reflectance leading to an increase in the amount of solar energy absorbed by the snowpack. This effect is also known as impurities direct radiative effect. The change in the amount of energy absorbed by the snowpack modifies the temperature profile inside the snowpack and in turn snow metamorphism (impurities indirect radiative effects). In this work, we used the detailed snowpack model SURFEX/ISBA-Crocus with an explicit representation of snow light-absorbing impurities content (Tuzet et al., 2017) fed by medium-resolution ALADIN-Climate atmospheric model to represent dust and black carbon atmospheric deposition fluxes. The model is used at two sites: Col de Porte (medium elevation site in the French Alps) and Torgnon (high elevation site in the Italian Alps). The simulations are compared to in-situ observations and used to quantify the effects of light-absorbing impurities on snow melt rate and timing. The respective parts of the direct and indirect radiative effects of light-absorbing impurities in snow are also computed for the two sites, emphasizing the need to account for the interactions between snow metamorphism and LAI radiative properties, to accurately predict the effects of light-absorbing impurities in snow. Moreover, we describe how automated hyperspectral reflectance can be used to estimate effective impurities surface content in snow. Finally we demonstrate how these reflectances measurements either from in situ or satellite data can be used via an assimilation scheme to constrain snowpack ensemble simulations and better predict the snowpack state and evolution.

  12. Responses of photosynthetic properties and chloroplast ultrastructure of two moss crusts from a desert biological soil crust to supplementary UV-B radiation

    NASA Astrophysics Data System (ADS)

    Hui, Rong; Li, Xinrong; Zhao, Yang; Pan, Yanxia

    2016-04-01

    Our understanding of plant responses to supplementary ultraviolet-B (UV-B) radiation due to stratospheric ozone depletion has improved over recent decades. However, research on biological soil crusts (BSCs) is scarce and it remains controversial. Laboratory studies were conducted to investigate the influence of UV-B radiation on the Bryum argenteum and Didymodon vinealis isolated from BSCs, which are both dominant species in moss crusts found within patches of shrubs and herbs in the Tengger Desert of northern China. The aim of the current work was to evaluate whether supplementary UV-B radiation affected photosynthetic properties and chloroplast ultrastructure of two moss crusts and whether response differences were observed between the crusts. Four levels of UV-B radiation of 2.75 (control), 3.08, 3.25, and 3.41 W m-2 was achieved using fluorescence tube systems for 10 days, simulating 0, 6, 9, and 12% of stratospheric ozone at the latitude of Shapotou, respectively. We measured photosynthetic apparatus as assessed by chlorophyll a fluorescence parameters, photosynthetic pigment contents, and observations of chloroplast ultrastructure. Additionally, soluble proteins and UV-B absorbing compounds were simultaneously investigated. The results of this study showed that chlorophyll a fluorescence parameters (i.e., the maximal quantum yield of PSII photochemistry, the effective quantum yield of PSII photochemistry, and photochemical quenching coefficient), photosynthetic pigment contents, soluble protein contents, total flavonoid contents and the ultrastructure were negatively influenced by elevated UV-B radiation and the degree of detrimental effects significantly increased with the intensity of UV-B radiation. Moreover, results demonstrated that the negative effects on photosynthesis and chloroplast ultrastructure were more serious in B. argenteum than that in D. vinealis. These results may not only provide a potential mechanism for supplemental UV-B effects on

  13. Leaf chemical changes induced in Populus trichocarpa by enhanced UV-B radiation and concomitant effects on herbivory by Chrysomela scripta (Coleoptera: Chrysomelidae).

    PubMed

    Warren, Jeffrey M; Bassman, John H; Eigenbrode, Sanford

    2002-11-01

    To assess the potential impact of enhanced ultraviolet-B (UV-B) radiation over two trophic levels, we monitored key leaf chemical constituents and related changes in their concentration to dietary preference and performance of a specialist insect herbivore. Ramets of Populus trichocarpa Torr. & Gray (black cottonwood) were subjected to near zero (0X), ambient (1X) or twice ambient (2X) doses of biologically effective UV-B radiation (UV-B(BE)) in a randomized block design using either a square-wave (greenhouse) or a modulated (field) lamp system. After a 3-month treatment period, apparent photosynthesis was determined in situ and plants were harvested for biomass determination. Leaf subsamples were analyzed for nitrogen, sulfur, chlorophylls, UV-absorbing compounds and protein-precipitable tannins. Effects of changes in these constituents on feeding by Chrysomela scripta Fab. (cottonwood leaf beetle) were determined by (1) adult feeding preference trials and (2) larval growth rate trials. Enhanced UV-B(BE) radiation had minimal effects on photosynthesis, growth, leaf area and biomass distribution. In the greenhouse study, concentrations of foliar nitrogen and chlorophylls increased, but tannins decreased slightly in young leaves exposed to enhanced UV-B(BE) radiation. There were no significant effects on these parameters in the field study. The concentration of methanol-extractable foliar phenolics increased in plants grown with enhanced UV-B(BE) radiation in both the greenhouse and field studies. In feeding preference trials, adult C. scripta chose 2X-treated tissue almost twice as often as 1X-treated tissue in both greenhouse and field studies, but differences were not statistically significant (P = 0.12). In the field study, first instar larvae grown to adult eclosion on 2X-treated leaves had a significant (P < 0.001) reduction in consumption efficiency compared with larvae grown on 1X-treated leaves. We conclude that effects of enhanced UV-B(BE) radiation at the

  14. UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis.

    PubMed

    Wan, Jinpeng; Zhang, Ping; Wang, Ruling; Sun, Liangliang; Wang, Wenying; Zhou, Huakun; Xu, Jin

    2018-01-01

    Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation.

  15. Optical and electron paramagnetic resonance studies of the excited triplet states of UV-B absorbers: 2-ethylhexyl salicylate and homomenthyl salicylate.

    PubMed

    Sugiyama, Kazuto; Tsuchiya, Takumi; Kikuchi, Azusa; Yagi, Mikio

    2015-09-26

    The energy levels and lifetimes of the lowest excited triplet (T1) states of UV-B absorbers, 2-ethylhexyl salicylate (EHS) and homomenthyl salicylate (HMS), and their deprotonated anions (EHS(-) and HMS(-)) were determined through measurements of phosphorescence and electron paramagnetic resonance (EPR) spectra in rigid solutions at 77 K. The observed T1 energies of EHS and HMS are higher than those of butylmethoxydibenzoylmethane, the most widely used UV-A absorber, and octyl methoxycinnamate, the most widely used UV-B absorber. The T1 states of EHS, HMS, EHS(-) and HMS(-) were assigned to almost pure (3)ππ* state from the observed T1 lifetimes and zero-field splitting parameters. EHS and HMS with an intramolecular hydrogen bond show a photoinduced phosphorescence enhancement in ethanol at 77 K. The EPR signals of the T1 states of EHS and HMS also increase in intensity with UV-irradiation time (photoinduced EPR enhancement). The T1 lifetimes of EHS and HMS at room temperature were determined through triplet-triplet absorption measurements in ethanol. The quantum yields of singlet oxygen production by EHS and HMS were determined by using time-resolved near-IR phosphorescence.

  16. Study the Characterization of Spectral Absorbance on Irradiated Milk Protein

    NASA Astrophysics Data System (ADS)

    Fohely, F.; Suardi, N.

    2018-04-01

    The milk has been adopted as a structural nature food for a long era since it is containing most of the growth factors, protective agents, and enzymes needed for the body. a few attempts have been conducted to treat the dairy products especially raw milk by the means of ionizing radiation. as its production has been an expanding industry for many years due to the high demands from the consumers worldwide, there is still some doubt about preserving these products by irradiation. In this work, a preliminary effort to describe the influences of ionizing radiation on raw milk’s protein will be devoted to measuring the spectral absorbance of the total protein (after subjected to varied radiation doses) by UV-VIS-NIR spectroscopy analysis. The absorbance spectrum then analyzed based on absorbance spectra of organic compounds. A comparison is made between the effects of different radiation doses to estimate the influence in milk’s structure.

  17. Dual-wavelength recording, a simple algorithm to eliminate interferences due to UV-absorbing substances in capillary electrophoresis.

    PubMed

    Seaux, Liesbeth; Van Houcke, Sofie; Dumoulin, Els; Fiers, Tom; Lecocq, Elke; Delanghe, Joris R

    2014-08-01

    Analytical interferences have been described due to the presence of various exogenous UV-absorbing substances in serum. Iodine-based X-ray contrast agents and various antibiotics have been reported to interfere with interpretation of serum protein pherograms, resulting in false diagnosis of paraproteinemia. In the present study, we have explored the possibility of measuring UV absorbance at two distinct wavelengths (210 and 246 nm) to distinguish between true and false paraproteins on a Helena V8 clinical electrophoresis instrument. This study demonstrates that most substances potentially interfering with serum protein electrophoresis show UV-absorption spectra that are distinct from those of serum proteins. Scanning at 246 nm allows detection of all described interfering agents. Comparing pherograms recorded at both wavelengths (210 and 246 nm) enables to distinguish paraproteins from UV-absorbing substances. In case of a true paraprotein, the peak with an electrophoretic mobility in the gamma-region decreases, whereas the X-ray contrast media and antibiotics show an increased absorption when compared to the basic setting (210 nm). The finding of iodine-containing contrast media interfering with serum protein electrophoresis is not uncommon. In a clinical series, interference induced by contrast media was reported in 54 cases (of 13 237 analyses), corresponding with a prevalence of 0.4%. In the same series, 1631 true paraproteins (12.3%) were detected. Implementation of the proposed algorithm may significantly improve the interpretation of routine electrophoresis results. However, attention should still be paid to possible interference due to presence of atypical proteins fractions (e.g., tumor markers, C3). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Absorbance detector for high performance liquid chromatography based on a deep-UV light-emitting diode at 235nm.

    PubMed

    da Silveira Petruci, João Flavio; Liebetanz, Michael G; Cardoso, Arnaldo Alves; Hauser, Peter C

    2017-08-25

    In this communication, we describe a flow-through optical absorption detector for HPLC using for the first time a deep-UV light-emitting diode with an emission band at 235nm as light source. The detector is also comprised of a UV-sensitive photodiode positioned to enable measurement of radiation through a flow-through cuvette with round aperture of 1mm diameter and optical path length of 10mm, and a second one positioned as reference photodiode; a beam splitter and a power supply. The absorbance was measured and related to the analyte concentration by emulating the Lambert-Beer law with a log-ratio amplifier circuitry. This detector showed noise levels of 0.30mAU, which is comparable with our previous LED-based detectors employing LEDs at 280 and 255nm. The detector was coupled to a HPLC system and successfully evaluated for the determination of the anti-diabetic drugs pioglitazone and glimepiride in an isocratic separation and the benzodiazepines flurazepam, oxazepam and clobazam in a gradient elution. Good linearities (r>0.99), a precision better than 0.85% and limits of detection at sub-ppm levels were achieved. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Conidia survival of Aspergillus section Nigri, Flavi and Circumdati under UV-A and UV-B radiation with cycling temperature/light regime.

    PubMed

    García-Cela, Maria Esther; Marín, Sonia; Reyes, Monica; Sanchis, Vicent; Ramos, Antonio J

    2016-04-01

    Bio-geographical differences in fungal infection distribution have been observed around the world, confirming that climatic conditions are decisive in colonization. This research is focused on the impact of ultraviolet radiation (UV) on Aspergillus species, based on the consideration that an increase in UV-B radiation may have large ecological effects. Conidia of six mycotoxigenic Aspergillus species isolated from vineyards located in the northeast and south of Spain were incubated for 15 days under light/dark cycles and temperatures between 20 and 30 °C per day. Additionally, 6 h of exposure to UV-A or UV-B radiation per day were included in the light exposure. UV irradiance used were 1.7 ± 0.2 mW cm(-2) of UV-A (peak 365 nm) and 0.10 ± 0.2 mW cm(-2) of UV-B (peak 312 nm). The intrinsic decrease in viability of conidia over time was accentuated when they were UV irradiated. UV-B radiation was more harmful. Conidial sensitivity to UV light was marked in Aspergillus section Circumdati. Conidia pigmentation could be related to UV sensitivity. Different resistance was observed within species belonging to sections Flavi and Nigri. An increase in UV radiation could lead to a reduction in the Aspergillus spp. inoculum present in the field (vineyards, nuts, cereal crops). In addition, it could unbalance the spore species present in the field, leading to a higher predominance of dark-pigmented conidia. © 2015 Society of Chemical Industry.

  20. UV/PAR radiations and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    NASA Astrophysics Data System (ADS)

    Para, J.; Charrière, B.; Matsuoka, A.; Miller, W. L.; Rontani, J. F.; Sempéré, R.

    2012-11-01

    Water masses from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC), and optical characteristics including UV and PAR diffuse attenuation (Kd), and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July to 27 August). Even with relatively low mean daily solar radiation incident on the sea surface (0.12 ± 0.03, 8.46 ± 1.64 and 18.09 ± 4.20 kJ m-2 for UV-B (305 nm), UV-A (380 nm) and PAR, respectively), we report significant light penetration with 10% irradiance depths (Z10% (λ)) reaching 9.5 m for 340 nm (UV-A) radiation in the Eastern sector and 4.5 m in the Mackenzie River influenced area (Western sector). Spectral absorption coefficients (aCDOM (350 nm) (m-1)) were significantly correlated to both diffuse attenuation coefficients (Kd) in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of UV solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. Extrapolating CDOM to DOC relationships, we estimate that ~ 16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. DOC and CDOM discharges by the Mackenzie River during the MALINA Cruise are estimated as ~ 0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1-C3) were identified by fluorescence Excitation/Emission Matrix Spectroscopy (EEMS) and PARAFAC analysis. Our results showed an in-situ biological component (C1) that co-dominated with a terrestrial humic-like component (C2) in the Mackenzie Delta sector, whereas the protein-like (C3) component dominated in the saltiest waters of the North East sector.

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

    NASA Astrophysics Data System (ADS)

    Zhou, Dianfeng; Heng, Hang; Ji, Kang; Ke, Weizhong

    2005-05-01

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

  2. Remote sensing of solar radiation absorbed and reflected by vegetated land surfaces

    NASA Technical Reports Server (NTRS)

    Myneni, Ranga B.; Asrar, Ghassem; Tanre, Didier; Choudhury, Bhaskar J.

    1992-01-01

    1D and 3D radiative-transfer models have been used to investigate the problem of remotely sensed determination of vegetated land surface-absorbed and reflected solar radiation. Calculations were conducted for various illumination conditions to determine surface albedo, soil- and canopy-absorbed photosynthetically active and nonactive radiation, and normalized difference vegetation index. Simple predictive models are developed on the basis of the relationships among these parameters.

  3. UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis

    PubMed Central

    Wan, Jinpeng; Zhang, Ping; Wang, Ruling; Sun, Liangliang; Wang, Wenying; Zhou, Huakun; Xu, Jin

    2018-01-01

    Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation. PMID:29868074

  4. The system of high accuracy UV spectral radiation system

    NASA Astrophysics Data System (ADS)

    Lin, Guan-yu; Yu, Lei; Xu, Dian; Cao, Dian-sheng; Yu, Yu-Xiang

    2016-10-01

    UV spectral radiation detecting and visible observation telescope is designed by the coaxial optical. In order to decrease due to the incident light polarization effect, and improve the detection precision, polarizer need to be used in the light path. Four pieces of quartz of high Precision UV radiation depolarizer retarder stack together is placed in front of Seya namioka dispersion unit. The coherent detection principle of modulation of light signal and the reference signal multiplied processing, increase the phase sensitive detector can be adjustment function, ensure the UV spectral radiation detection stability. A lock-in amplifier is used in the electrical system to advance the accuracy of measurement. To ensure the precision measurement detected, the phase-sensitive detector function can be adjustable. the output value is not more than 10mV before each measurement, so it can be ensured that the stability of the measured radiation spectrum is less than 1 percent.

  5. Thin films with disordered nanohole patterns for solar radiation absorbers

    NASA Astrophysics Data System (ADS)

    Fang, Xing; Lou, Minhan; Bao, Hua; Zhao, C. Y.

    2015-06-01

    The radiation absorption in thin films with three disordered nanohole patterns, i.e., random position, non-uniform radius, and amorphous pattern, are numerically investigated by finite-difference time-domain (FDTD) simulations. Disorder can alter the absorption spectra and has an impact on the broadband absorption performance. Compared to random position and non-uniform radius nanoholes, amorphous pattern can induce a much better integrated absorption. The power density spectra indicate that amorphous pattern nanoholes reduce the symmetry and provide more resonance modes that are desired for the broadband absorption. The application condition for amorphous pattern nanoholes shows that they are much more appropriate in absorption enhancement for weak absorption materials. Amorphous silicon thin films with disordered nanohole patterns are applied in solar radiation absorbers. Four configurations of thin films with different nanohole patterns show that interference between layers in absorbers will change the absorption performance. Therefore, it is necessary to optimize the whole radiation absorbers although single thin film with amorphous pattern nanohole has reached optimal absorption.

  6. Effective UV radiation from model calculations and measurements

    NASA Technical Reports Server (NTRS)

    Feister, Uwe; Grewe, Rolf

    1994-01-01

    Model calculations have been made to simulate the effect of atmospheric ozone and geographical as well as meteorological parameters on solar UV radiation reaching the ground. Total ozone values as measured by Dobson spectrophotometer and Brewer spectrometer as well as turbidity were used as input to the model calculation. The performance of the model was tested by spectroradiometric measurements of solar global UV radiation at Potsdam. There are small differences that can be explained by the uncertainty of the measurements, by the uncertainty of input data to the model and by the uncertainty of the radiative transfer algorithms of the model itself. Some effects of solar radiation to the biosphere and to air chemistry are discussed. Model calculations and spectroradiometric measurements can be used to study variations of the effective radiation in space in space time. The comparability of action spectra and their uncertainties are also addressed.

  7. Ultraviolet radiation exposure from UV-transilluminators.

    PubMed

    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 < or =25 cm from the UV-transilluminator's filter surface. Daily exposure 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. Changes in growth, leaf anatomy and pigment concentrations in pea under modulated UV-B field treatments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Day, T.A.; Howells, B.W.; Ruhland, C.T.

    1995-06-01

    In growth-chamber and greenhouse studies, garden pea is typically quite sensitive to enhanced UV-B radiation (280-320 nm). We assessed whether growth of pea was reduced under more ecologically relevant UV-B enhancements by employing modulated field lampbanks simulating 0, 16 or 24% ozone depletion. We also examined if these UV-B treatments altered leaf anatomy and concentrations of chlorophyll and UV-B-absorbing compounds, and whether this was dependent on leaf age. We used Pisum sativum mutant Argenteum which has an easily detachable epidermis that allowed us to compare concentrations in epidermal and mesophyll tissues. There were no significant UV-B effects on whole-plant growth.more » Of the 15 leaf-level parameters we examined, UV-B had a strong effect on only two parameters: the ratio of UV-B-absorbing compounds to chlorophyll (which increased with UV-B dose), and stomatal density of the adaxial surface (which decreased with UV-B dose). Chlorophyll concentrations tended to decrease, while the proportion of UV-B-absorbing compounds in the adaxial epidermis tended to increase with UV-B dose (p = 0.11 for both). In contrast to UV-B effects, we found strong leaf-age effects on nearly all parameters except the ratio of UV-B-absorbing compounds to chlorophyll, which remained relatively constant with leaf age.« less

  9. Effects of simulated solar UVB radiation on early developmental stages of the northwestern salamander (Ambystoma gracile) from three lakes

    USGS Publications Warehouse

    Calfee, R.D.; Little, E.E.; Pearl, C.A.; Hoffman, R.L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290-320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66 of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation. Copyright 2010 Society for the Study of Amphibians and Reptiles.

  10. Interactive effects of elevated ozone and UV-B radiation on soil nematode diversity.

    PubMed

    Bao, Xuelian; Li, Qi; Hua, Jianfeng; Zhao, Tianhong; Liang, Wenju

    2014-01-01

    Ultraviolet-B (UV-B) radiation and elevated tropospheric ozone may cause reductions in the productivity and quality of important agricultural crops. However, research regarding their interactive effect is still scarce, especially on the belowground processes. Using the open top chambers experimental setup, we monitored the response of soil nematodes to the elevated O3 and UV-B radiation individually as well as in combination. Our results indicated that elevated O3 and UV-B radiation have impact not only on the belowground biomass of plants, but also on the community structure and functional diversity of soil nematodes. The canonical correspondence analysis suggested that soil pH, shoot biomass and microbial biomass C and N were relevant parameters that influencing soil nematode distribution. The interactive effects of elevated O3 and UV-B radiation was only observed on the abundance of bacterivores. UV-B radiation significantly increased the abundance of total nematodes and bacterivores in comparison with the control at pod-filling stage of soybean. Following elevated O3, nematode diversity index decreased and dominance index increased relative to the control at pod-filling stage of soybean. Nematode functional diversity showed response to the effects of elevated O3 and UV-B radiation at pod-bearing stage. Higher enrichment index and lower structure index in the treatment with both elevated O3 and UV-B radiation indicated a stressed soil condition and degraded soil food web. However, the ratios of nematode trophic groups suggested that the negative effects of elevated O3 on soil food web may be weakened by the UV-B radiations.

  11. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    NASA Technical Reports Server (NTRS)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  12. Disposal of Energy by UV-B Sunscreens

    NASA Astrophysics Data System (ADS)

    Nordlund, Thomas; Krishnan, Rajagopal

    2008-03-01

    Ideal sunscreens absorb dangerous UV light and dispose of the energy safely. ``Safe disposal'' usually means conversion to heat. However, efficient absorption entails a high radiative rate, which implies high energy-transfer and other rates, unless some process intervenes to ``defuse'' the excited state. We studied the excited-state kinetics of three UV-B (290-320 nm) sunscreens by absorption, steady-state and time-resolved fluorescence. Excited-state rate analysis suggests that some sunscreens have low radiative-rate ``dark'' states, in addition to normal excited states.* We deduce dark states when sunscreens of high extinction coefficient do not show lifetimes and total emission consistent with such high radiative rates. A high radiative rate, accompanied by efficient fluorescence emission and/or transfer, may be unfavorable for a sunscreen. In spite of its dark excited state, padimate O shows significant re-emission of light in the UV-A (320-400 nm) and energy transfer to a natural component of excised skin, probably collagen. * Krishnan, R. and T.M. Nordlund (2007) J. Fluoresc. DOI 10.1007/s10895-007-0264-3.

  13. The effects of simulated solar UVB radiation on early developmental stages of the Northwestern Salamander (Ambystoma gracile) from three lakes

    USGS Publications Warehouse

    Calfee, Robin D.; Little, Edward E.; Pearl, Christopher A.; Hoffman, Robert L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290–320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66% of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation.

  14. Theoretical insights on flavanones as antioxidants and UV filters: A TDDFT and NLMO study.

    PubMed

    Ajmala Shireen, P; Abdul Mujeeb, V M; Muraleedharan, K

    2017-05-01

    UV radiations can cause several irritations to the skin like sunburn, photo aging and even skin cancer. Sunscreens are widely used to protect the skin against these harmful radiations. One of the ingredients present in these sunscreens are organic molecules capable of absorbing these harmful radiations. Recently, the search is on for antioxidant molecules which can act as UV filters as they can facilitate photo protection. In this study, a computational investigation based on density functional theory (DFT) is attempted on flavanones namely pinocembrin, pinostrobin and alpinetin found in Boesenbergia pandurata. Several quantum chemical descriptors are computed to understand the antioxidant potentiality of these molecules. Quantum chemical descriptors of these flavanone molecules are found to be comparable to that of well-known anti-oxidant quercetin. UV response of these molecules are studied using time dependent density functional theory (TD-DFT) formalism and by means of natural bond orbital (NBO) theory. It could be seen that these molecules exhibit a broad absorption in the UV region 270-390nm. This falls exactly in the region of harmful UVB and UVA radiation. Thus, these molecules have the potential to absorb the harmful UV radiation. From NLMO cluster studies, the orbital contribution to absorption is explained. In flavanones, unlike other classes of flavonoids, there is a discontinuity in the electron conjugation due to the absence of C2C3 double bond. This might be the key structural feature that leads to the absorption of these molecules to be centered around the UV region. These molecules can thus be treated as promising candidates for antioxidant UV filters in sunscreens. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. UV Radiation Damage and Bacterial DNA Repair Systems

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  16. Venus upper clouds and the UV-absorber from MESSENGER/MASCS observations

    NASA Astrophysics Data System (ADS)

    Perez-Hoyos, Santiago; Sanchez-Lavega, Agustin; Garcia Munoz, Antonio; Irwin, Patrick; Peralta, Javier; Holsclaw, Greg; McClintock, William

    2014-11-01

    In June 2007, the MESSENGER spacecraft performed its second Venus flyby on its route to Mercury. The spacecraft’s MASCS instrument (VIRS channel) acquired numerous spectra of the sunlight reflected from the equatorial region of the planet at wavelengths from the near ultraviolet (300nm) to the near infrared (1450 nm). In this work we present an analysis of the data and their spectral and spatial variability following the mission footprint on the Venus disk. In order to reproduce the observed reflectivity and obtain information on the upper clouds and the unknown UV absorber, we use the NEMESIS retrieval code, including SO2 , CO2 and H2O absorption together with absorption and scattering by mode-1, -2 and -3 cloud particles. This spectral range provides sensitivity to the uppermost cloud levels, above 60 km. Vertical profiles of the mode-1 and mode-2 particles have been retrieved along the equatorial region of Venus, with average retrieved sounding levels of 70 +/- 2 km at 1 micron, in good agreement with previous investigations. This spectral range is also very interesting because of the existence of a mysterious absorber in the blue and UV side of the reflected spectra, whose origin remains as one of the key questions about the Venus atmosphere. Here we report a comparison with some of the previously proposed absorbers: (1) sulfur-related compounds (amorphous and liquid sulfur, S3, S4, S8, S2O); (2) chlorine related species (Cl2, FeCl3); (3) organics (C3O2, Croconic acid). Preliminary results show that the first group provides better fits to the data, although combinations of the proposed agents might be required in order to produce better results. Acknowledgements: This work was supported by the Spanish MICIIN projects AYA2009- 10701, AYA2012-38897-C02-01, and AYA2012-36666 with FEDER support, PRICIT-S2009/ESP-1496, Grupos Gobierno Vasco IT765-13, and UPV/EHU UFI11/55. S.P.-H. acknowledges support from the Jose Castillejo Program funded by Ministerio de Educaci

  17. Heavy-ion-induced sucrose radicals investigated using EPR and UV spectroscopy.

    PubMed

    Nakagawa, Kouichi; Karakirova, Yordanka; Yordanov, Nicola D

    2015-05-01

    The potential use of a sucrose dosimeter for estimating both linear energy transfer (LET) and the absorbed dose of heavy ion and X-ray radiation was investigated. The stable free radicals were produced when sucrose was irradiated with heavy ions, such as helium, carbon, silicon and neon ions, and when the X-ray radiation was similar to the obtained electron paramagnetic resonance (EPR) spectra, which were ∼7 mT wide and composed of several hyperfine structures. In addition, the total spin concentration resulting from heavy-ion irradiation increased linearly as the absorbed dose increased, and decreased logarithmically as the LET increased. These empirical relations imply that the LET at a certain dose can be determined from the spin concentration. For sucrose and alanine, both cross-sections following C-ion irradiation with a 50 Gy dose were ∼1.3 × 10(-12) [μm(2)], taking into account the molecular size of the samples. The values of these cross-sections imply that multiple ionizing particles were involved in the production of stable radicals. Furthermore, UV absorbance at 267 nm of an aqueous solution of irradiated sucrose was found to linearly increase with increasing absorbed dose. Therefore, the EPR and UV results suggest that sucrose can be a useful dosimeter for heavy-ion irradiation. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  18. Studies on the performance of TiO{sub 2} thin films as protective layer to chlorophyll in Ocimum tenuiflorum L from UV radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Malliga, P.; Selvi, B. Karunai; Pandiarajan, J.

    Thin films of TiO{sub 2} were prepared on glass substrates using sol-gel dip coating technique. The films with 10 coatings were prepared and annealed at temperatures 350°C, 450°C and 550°C for 1 hour in muffle furnace. The annealed films were characterized by X – Ray diffraction (XRD), UV – Visible, AFM, Field Effect Scanning Electron Microscopy (FESEM) and EDAX studies. Chlorophyll has many health benefits due to its structural similarity to human blood and its good chelating ability. It has antimutagenic and anticarcinogenic properties. UV light impairs photosynthesis and reduces size, productivity, and quality in many of the crop plantmore » species. Increased exposure of UV light reduces chlorophyll contents a, b and total content in plants. Titanium Dioxide (TiO{sub 2}) is a wide band gap semiconductor and efficient light harvester. TiO{sub 2} has strong UltraViolet (UV) light absorbing capability. Here, we have studied the performance of TiO{sub 2} thin films as a protective layer to the chlorophyll contents present in medicinal plant, tulsi (Ocimum tenuiflorum L) from UV radiation. The study reveals that crystallite size increases, transmittance decreases and chlorophyll contents increases with increase in annealing temperature. This study showed that TiO{sub 2} thin films are good absorber of UV light and protect the chlorophyll contents a, b and total content in medicinal plants.« less

  19. SOLAR UV RADIATION AND AQUATIC BIOGEOCHEMISTRY

    EPA Science Inventory

    During the past decade significant interest has developed in the influence of solar UV radiation on biogeochemical cycles in surface waters of lakes and the sea. A major portion of this research has focused on photoreactions of the colored component of dissolved organic matter, ...

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

    PubMed Central

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

    2013-01-01

    Plants from the Allium genus are valued worldwide for culinary flavor and medicinal attributes. In this study, 16 cultigens of bunching onion (Allium fistulosum L.) were grown in a glasshouse under filtered UV radiation (control) or supplemental UV-B radiation [7.0 μmol·m−2 ·s−2 (2.68 W·m−2)] to determine impacts on growth, physiological parameters, and nutritional quality. Supplemental UV-B radiation influenced shoot tissue carotenoid concentrations in some, but not all, of the bunching onions. Xanthophyll carotenoid pigments lutein and β-carotene and chlorophylls a and b in shoot tissues differed between UV-B radiation treatments and among cultigens. Cultigen “Pesoenyj” responded to supplemental UV-B radiation with increases in the ratio of zeaxanthin + antheraxanthin to zeaxanthin + antheraxanthin + violaxanthin, which may indicate a flux in the xanthophyll carotenoids towards deepoxydation, commonly found under high irradiance stress. Increases in carotenoid concentrations would be expected to increase crop nutritional values. PMID:23606817

  1. Radiative forcing by light-absorbing aerosols of pyrogenetic iron oxides.

    PubMed

    Ito, Akinori; Lin, Guangxing; Penner, Joyce E

    2018-05-09

    Iron (Fe) oxides in aerosols are known to absorb sun light and heat the atmosphere. However, the radiative forcing (RF) of light-absorbing aerosols of pyrogenetic Fe oxides is ignored in climate models. For the first time, we use a global chemical transport model and a radiative transfer model to estimate the RF by light-absorbing aerosols of pyrogenetic Fe oxides. The model results suggest that strongly absorbing Fe oxides (magnetite) contribute a RF that is about 10% of the RF due to black carbon (BC) over East Asia. The seasonal average of the RF due to dark Fe-rich mineral particles over East Asia (0.4-1.0 W m -2 ) is comparable to that over major biomass burning regions. This additional warming effect is amplified over polluted regions where the iron and steel industries have been recently developed. These findings may have important implications for the projection of the climate change, due to the rapid growth in energy consumption of the heavy industry in newly developing countries.

  2. Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer.

    PubMed

    Liu, Wei; Dai, Xing; Xie, Jian; Silver, Mark A; Zhang, Duo; Wang, Yanlong; Cai, Yawen; Diwu, Juan; Wang, Jian; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

    2018-02-07

    The accurate detection of UV radiation is required in a wide range of chemical industries and environmental or biological related applications. Conventional methods taking advantage of semiconductor photodetectors suffer from several drawbacks such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. Searching for new strategies or materials serving as precise UV dosage sensor with extremely low detection limit is still highly desirable. In this work, a radiation resistant uranium coordination polymer [UO 2 (L)(DMF)] (L = 5-nitroisophthalic acid, DMF = N,N-dimethylformamide, denoted as compound 1) was successfully synthesized through mild solvothermal method and investigated as a unique UV probe with the detection limit of 2.4 × 10 -7 J. On the basis of the UV dosage dependent luminescence spectra, EPR analysis, single crystal structure investigation, and the DFT calculation, the UV-induced radical quenching mechanism was confirmed. Importantly, the generated radicals are of significant stability which offers the opportunity for measuring the accumulated UV radiation dosage. Furthermore, the powder material of compound 1 was further upgraded into membrane material without loss in luminescence intensity to investigate the real application potentials. To the best of our knowledge, compound 1 represents the most sensitive coordination polymer based UV dosage probe reported to date.

  3. Measurements of DNA Damage and Repair in Bacillus anthracis Sterne Spores by UV Radiation

    DTIC Science & Technology

    2014-09-18

    MEASUREMENTS OF DNA DAMAGE AND REPAIR IN BACILLUS ANTHRACIS STERNE SPORES BY UV RADIATION...AFIT-ENP-T-14-S-01 MEASUREMENTS OF DNA DAMAGE AND REPAIR IN BACILLUS ANTHRACIS STERNE SPORES BY UV RADIATION THESIS Presented to the... DAMAGE AND REPAIR IN BACILLUS ANTHRACIS STERNE SPORES BY UV RADIATION Chelsea C. Marcum, BS Approved

  4. Long-term variations of the UV-B radiation over Central Europe since early 1960s, as revealed from the UV observations and reconstructed data

    NASA Astrophysics Data System (ADS)

    Krzyscin, J. W.

    2003-04-01

    A method of reconstruction of the UV variations for periods when UV-B measurements were not carried out is proposed. The reconstruction is based on observations of total (Sun+sky) radiation by a pyranometer, Dobson total ozone, sunshine duriation from the Campbel Stokes heliograph, and atmospheric column water content taken from NCEP/NOAA reanalysis. Modeled all-sky erythemaly weighted daily dose is calculated as a product of the cloud reduction factor (CRF) over UV range and clear-sky dose from a radiative transfer model. CRF over UV range is estimated from measured CRF for total solar radiation and the statistical dependence relating CRF over UV with that over whole solar spectrum. The measured daily UV doses and daily sum of total radiation taken at Belsk, Poland (52N, 21E) for the period 1976-2001 have been used to construct the regressions for various solar zenith angles. The time series of monthly means from the modeled daily UV doses follows the observed monthly means supporting the possibility of reconstruction of the UV time series for other periods. An inspection of the long-term stability of total radiation measurements is necessary to discuss trends in the reconstructed time series. We examine the data homogeneity analyzing the ratio of the observed to modeled total radiation for fully clear sky days that are selected from the daily values of sunshine duration measured by the Campbel-Stokes heliograph. Combining reconstructed and observed monthly means of the UV doses we found a positive trend in the UV radiation in the period 1980-1995 and almost constant UV level for other periods (early 60s up to 1980, and 1995-2001). The trend pattern suggests dominating role of the long-term total ozone forcing on the UV level with a small impact of the long-term changes in the cloud/aerosol properties.

  5. The mechanisms of protection of antioxidants on Nostoc sphaeroides against UV-B radiation

    NASA Astrophysics Data System (ADS)

    Wang, G. H.

    UV radiation is one of space harmful factor for earth organisms in space exploration In the present work we studied on the role of antioxidant system in Nostoc sphaeroides K u tz Cyanobacteria and the effects of exogenous antioxidant molecules on its photosynthetic rate under UV-B radiation It was found that UV-B radiation decreased the photosynthetic activity of cyanobacterium but promoted the activity of antioxidant system to protect photosystem II PSII and exogenous antioxidant sodium nitroprusside SNP N-acetylcysteine NAC had an obvious protection on PSII activity under UV-B radiation The activity of SOD Superoxide Dismutase EC 1 15 1 1 CAT Catalase EC 1 11 1 6 POD Peroxidase EC 1 11 1 7 and content of MDA and ASC were improved by 0 5mM and 1mM SNP but 0 1mM SNP decreased the activity of antioxide system Exogenous NAC addition decreased the activity of SOD POD CAT and the content MDA and ASC but exogenous NAC addition increased the content of GSH The results suggested that exogenous SNP and NAC may protect algae by different mechanisms in which SNP maybe play double roles as sources of reactive free radicals or ROS scavengers in formation of algae s protection of PSII under UV-B radiation while NAC does function as antioxidant reagent or precursor of glutathione which could protect PSII directly from UV-B radiation Keyword antioxidant system exogenous or endogenous antioxidant Nostoc sphaeroides photosynthesis UV-B radiation

  6. Photoexcited singlet and triplet states of a UV absorber ethylhexyl methoxycrylene.

    PubMed

    Kikuchi, Azusa; Hata, Yuki; Kumasaka, Ryo; Nanbu, Yuichi; Yagi, Mikio

    2013-01-01

    The excited states of UV absorber, ethylhexyl methoxycrylene (EHMCR) have been studied through measurements of UV absorption, fluorescence, phosphorescence and electron paramagnetic resonance (EPR) spectra in ethanol. The energy levels of the lowest excited singlet (S1) and triplet (T1) states of EHMCR were determined. The energy levels of the S1 and T1 states of EHMCR are much lower than those of photolabile 4-tert-butyl-4'-methoxydibenzoylmethane. The energy levels of the S1 and T1 states of EHMCR are lower than those of octyl methoxycinnamate. The weak phosphorescence and EPR B(min) signals were observed and the lifetime was estimated to be 93 ms. These facts suggest that the significant proportion of the S1 molecules undergoes intersystem crossing to the T1 state, and the deactivation process from the T1 state is predominantly radiationless. The photostability of EHMCR arises from the (3)ππ* character in the T1 state. The zero-field splitting (ZFS) parameter in the T1 state is D** = 0.113 cm(-1). © 2012 The Authors Photochemistry and Photobiology © 2012 The American Society of Photobiology.

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

    PubMed

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

    2012-02-01

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

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

    PubMed

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

    2010-01-01

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

  9. Effects of near-UV radiation on the protein of the grey squirrel lens.

    PubMed

    Zigman, S; Paxhia, T; Waldron, W

    1988-06-01

    In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking.

  10. Parkin regulates translesion DNA synthesis in response to UV radiation.

    PubMed

    Zhu, Xuefei; Ma, Xiaolu; Tu, Yingfeng; Huang, Min; Liu, Hongmei; Wang, Fengli; Gong, Juanjuan; Wang, Jiuqiang; Li, Xiaoling; Chen, Qian; Shen, Hongyan; Zhu, Shu; Wang, Yun; Liu, Yang; Guo, Caixia; Tang, Tie-Shan

    2017-05-30

    Deficiency of Parkin is a major cause of early-onset Parkinson's disease (PD). Notably, PD patients also exhibit a significantly higher risk in melanoma and other skin tumors, while the mechanism remains largely unknown. In this study, we show that depletion of Parkin causes compromised cell viability and genome stability after ultraviolet (UV) radiation. We demonstrate that Parkin promotes efficient Rad18-dependent proliferating cell nuclear antigen (PCNA) monoubiquitination by facilitating the formation of Replication protein A (RPA)-coated ssDNA upon UV radiation. Furthermore, Parkin is found to physically interact with NBS1 (Nijmegen breakage syndrome 1), and to be required for optimal recruitment of NBS1 and DNA polymerase eta (Polη) to UV-induced damage sites. Consequently, depletion of Parkin leads to increased UV-induced mutagenesis. These findings unveil an important role of Parkin in protecting genome stability through positively regulating translesion DNA synthesis (TLS) upon UV damage, providing a novel mechanistic link between Parkin deficiency and predisposition to skin cancers in PD patients.

  11. Response of Two Legumes to Two Ultraviolet-B Radiation Regimes

    NASA Technical Reports Server (NTRS)

    Levy, Daniel L.; Skiles, J. W.

    2000-01-01

    Depletion of the stratospheric ozone layer has been directly linked to increased levels of UV radiation at the earth's surface. The purpose of this study was to evaluate the responses of soybean (Glycine max) and alfalfa (Medicago sativa) to increased UV-B radiation (280-320 nm). Soybean and alfalfa were grown successively in a growth chamber that provided UV-B intensities 45% above nominal summer field levels. Mylar-D (UVB opaque) and mono-acetate (UV-B transparent) films were used to establish the two UV-B treatments. Soybean grown under increased UV showed 21% smaller internodal lengths and higher concentrations of UV-B absorbing pigments (i.e. flavonoids) compared to plants grown under no UV. Significant results for alfalfa included 22% greater leaf flavonoid concentration under increased UV, 14% greater leaf chlorophyll concentration under no UV, and 32% greater above-ground biomass with no UV. These leguminous species possess mechanisms that protect against UV-B damage as indicated by increases in foliar concentrations of UV-B absorbing compounds. Alfalfa appears to be more sensitive to UV-B damage than soybean. Remote sensing of chlorophyll fluorescence may offer a means of monitoring UV-induced plant stress and damage.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  13. Long-term changes in pigmentation of arctic Daphnia provide potential for reconstructing aquatic UV exposure

    NASA Astrophysics Data System (ADS)

    Nevalainen, Liisa; Rantala, Marttiina V.; Luoto, Tomi P.; Ojala, Antti E. K.; Rautio, Milla

    2016-07-01

    Despite the biologically damaging impacts of solar ultraviolet radiation (UV) in nature, little is known about its natural variability, forcing mechanisms, and long-term effects on ecosystems and organisms. Arctic zooplankton, for example the aquatic keystone genus Daphnia (Crustacea, Cladocera) responds to biologically damaging UV by utilizing photoprotective strategies, including pigmentation. We examined the preservation and content of UV-screening pigments in fossil Daphnia remains (ephippia) in two arctic lake sediment cores from Cornwallis Island (Lake R1), Canada, and Spitsbergen (Lake Fugledammen), Svalbard. The aims were to document changes in the degree of UV-protective pigmentation throughout the past centuries, elucidate the adaptive responses of zooplankton to long-term variations in UV exposure, and estimate the potential of fossil zooplankton pigments in reconstructing aquatic UV regimes. The spectroscopic absorbance measurements of fossil Daphnia ephippia under UV (280-400 nm) and visible light (400-700 nm) spectral ranges indicated that melanin (absorbance maxima at UV wavebands 280-350 nm) and carotenoids (absorbance maxima at 400-450 nm) pigments were preserved in the ephippia in both sediment cores. Downcore measurements of the most important UV-protective pigment melanin (absorbance measured at 305 and 340 nm) showed marked long-term variations in the degree of melanisation. These variations likely represented long-term trends in aquatic UV exposure and were positively related with solar radiation intensity. The corresponding trends in melanisation and solar activity were disrupted at the turn of the 20th century in R1, but remained as strong in Fugledammen. The reversed trends in the R1 core were simultaneous with a significant aquatic community reorganization taking place in the lake, suggesting that recent environmental changes, likely related to climate warming had a local effect on pigmentation strategies. This time horizon is also

  14. Raman spectroscopic analysis of the responds of desert cyanobacterium Nostoc sp under UV-B radiation

    NASA Astrophysics Data System (ADS)

    Wang, Gaohong; Hao, Zongjie; Hu, Chunxiang; Liu, Yongding

    Cyanobacteria are renowned for tolerating extremes of desiccation, UV radiation, freezethaw cycles, hypersalinity and oligotrophy, which make them as candidate par excellence for terraforming in extraterrestrial planet. Recently Raman spectrum was applied to study the biochemical information changes in different field of life science. In this study, we investigated the respond of desert cyanobactreium Nostoc sp under UV-B radiation via FT-Raman spectra. It was found that the spectral biomarkers of protectant molecular of UV radiation such as β-carotene and scytonemin were induced by UV-B radiation, but Chlorophyll a content was decreased, and also the photosynthesis activity was inhibited significantly. After light adaptation without UV-B radiation, the Chlorophyll a content and photosynthesis activity returned to high level, butβ-carotene and scytonemin content remained in the cells. Those results indicated that desert Cyanobacteria have good adaptation ability for UV-B radiation and synthesis of protectant molecular may be an effective strategy for its adaptation in evolution.

  15. Interspecific Variability in Sensitivity to UV Radiation and Subsequent Recovery in Selected Isolates of Marine Bacteria†

    PubMed Central

    Arrieta, Jesús María; Weinbauer, Markus G.; Herndl, Gerhard J.

    2000-01-01

    The interspecific variability in the sensitivity of marine bacterial isolates to UV-B (295- to 320-nm) radiation and their ability to recover from previous UV-B stress were examined. Isolates originating from different microenvironments of the northern Adriatic Sea were transferred to aged seawater and exposed to artificial UV-B radiation for 4 h and subsequently to different radiation regimens excluding UV-B to determine the recovery from UV-B stress. Bacterial activity was assessed by thymidine and leucine incorporation measurements prior to and immediately after the exposure to UV-B and after the subsequent exposure to the different radiation regimens. Large interspecific differences among the 11 bacterial isolates were found in the sensitivity to UV-B, ranging from 21 to 92% inhibition of leucine incorporation compared to the bacterial activity measured in dark controls and from 14 to 84% for thymidine incorporation. Interspecific differences in the recovery from the UV stress were also large. An inverse relation was detectable between the ability to recover under dark conditions and the recovery under photosynthetic active radiation (400 to 700 nm). The observed large interspecific differences in the sensitivity to UV-B radiation and even more so in the subsequent recovery from UV-B stress are not related to the prevailing radiation conditions of the microhabitats from which the bacterial isolates originate. Based on our investigations on the 11 marine isolates, we conclude that there are large interspecific differences in the sensitivity to UV-B radiation and even larger differences in the mechanisms of recovery from previous UV stress. This might lead to UV-mediated shifts in the bacterioplankton community composition in marine surface waters. PMID:10742228

  16. Effect of topical sunscreens on the UV-radiation-induced suppression of the alloactivating capacity in human skin in vivo.

    PubMed

    van Praag, M C; Out-Luyting, C; Claas, F H; Vermeer, B J; Mommaas, A M

    1991-10-01

    Exposure of mice or humans to solar or artificial ultraviolet radiation (UV) has been shown to induce a number of changes in the immune system that may influence their susceptibility to skin tumors. The protective effect of sunscreens on these changes is not clear. Thirty-two patients with a variety of dermatoses routinely undergoing treatment with standard UVB (n = 19) or PUVA (n = 13) therapy were studied. One of the two tested sunscreens or its vehicle was applied to the right flexor forearm immediately prior to each total-body UV exposure. Epidermal sheets were obtained by the suction-blister method from the left flexor forearm before treatment and from both flexor forearms after 4 weeks of photo- or photochemotherapy and used as stimulator epidermal cells (EC) in the mixed epidermal cell-lymphocyte reaction (MECLR). After 4 weeks of either UVB or PUVA therapy the MECLR responses on EC from both arms were markedly decreased. Neither the tested sunscreens nor their vehicles prevented the UV-induced suppression of the alloactivating capacity. The failure of sunscreens to protect against the UV-induced suppression of the alloactivating capacity could be explained in two ways. First, the energy not absorbed by the sunscreen could be sufficient to induce suppression of the alloactivating capacity. An alternative explanation could be systemic immune suppression by UV. In order to discriminate between these possibilities only the right forearms of 10 healthy volunteers, treated with a sunscreen or its vehicle, were irradiated with UVB during 4 weeks. In this manner systemic immune suppression by UVB could be excluded. This experiment resulted in a similar suppression of the MECLR responses, as induced by total body UVB irradiation, without any protection by the sunscreen. Apparently, the UV dose not absorbed by the sunscreen was capable to induce suppression of the alloactivating capacity. Our results indicate that people protected from sunburn by sunscreens may be

  17. UV/PAR radiation and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    NASA Astrophysics Data System (ADS)

    Para, J.; Charrière, B.; Matsuoka, A.; Miller, W. L.; Rontani, J. F.; Sempéré, R.

    2013-04-01

    Surface waters from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC), and optical characteristics including UV (ultraviolet) radiation and PAR (photosynthetically active radiation) diffuse attenuation (Kd), and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July to 27 August). Spectral absorption coefficients (aCDOM (350 nm) (m-1)) were significantly correlated to both diffuse attenuation coefficients (Kd) in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of both UV and PAR solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. While the Mackenzie input is the main driver of CDOM dynamics in low salinity waters, locally, primary production can create significant increases in CDOM. Extrapolating CDOM to DOC relationships, we estimate that ∼16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. The discharges of DOC and its chromophoric subset (CDOM) by the Mackenzie River during the MALINA cruise are estimated as ∼0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1-C3) were identified by fluorescence excitation/emission matrix spectroscopy (EEMS) and parallel factor (PARAFAC) analysis. Our results showed an aquatic dissolved organic matter (DOM) component (C1), probably produced in the numerous lakes of the watershed, that co-dominated with a terrestrial humic-like component (C2) in the Mackenzie Delta Sector. This aquatic DOM could partially explain the high CDOM spectral slopes observed in the Beaufort Sea.

  18. Reconstruction of solar spectral surface UV irradiances using radiative transfer simulations.

    PubMed

    Lindfors, Anders; Heikkilä, Anu; Kaurola, Jussi; Koskela, Tapani; Lakkala, Kaisa

    2009-01-01

    UV radiation exerts several effects concerning life on Earth, and spectral information on the prevailing UV radiation conditions is needed in order to study each of these effects. In this paper, we present a method for reconstruction of solar spectral UV irradiances at the Earth's surface. The method, which is a further development of an earlier published method for reconstruction of erythemally weighted UV, relies on radiative transfer simulations, and takes as input (1) the effective cloud optical depth as inferred from pyranometer measurements of global radiation (300-3000 nm); (2) the total ozone column; (3) the surface albedo as estimated from measurements of snow depth; (4) the total water vapor column; and (5) the altitude of the location. Reconstructed daily cumulative spectral irradiances at Jokioinen and Sodankylä in Finland are, in general, in good agreement with measurements. The mean percentage difference, for instance, is mostly within +/-8%, and the root mean square of the percentage difference is around 10% or below for wavelengths over 310 nm and daily minimum solar zenith angles (SZA) less than 70 degrees . In this study, we used pseudospherical radiative transfer simulations, which were shown to improve the performance of our method under large SZA (low Sun).

  19. Response of Two Plant Species to Two Ultraviolet-B Radiation Regimes

    NASA Technical Reports Server (NTRS)

    Levy, Daniel L.; Skiles, J. W.; Peterson, David (Technical Monitor)

    1996-01-01

    The depleted stratospheric ozone layer has been directly linked to increased levels of ultraviolet radiation at the earth's surface. It is important to understand what effect this will have on plants. We tested the hypothesis that in response to increased UV-B radiation (280-320 man), soybean (Glycine max Merrill) and alfalfa (Mercado Saliva L.) would produce higher concentrations of flavonoids than plants screened from UV-B. Soybean and alfalfa plants were grown successively in a growth chamber that provided UV-B radiation intensities 45% above summer field levels. A wooden frame was used to suspend mylar-D film over one group of plants and mono-acetate film over another group. Mylar is opaque in the 280-316 nm range, and acetate absorbs most radiation from 280-290 nm and then reduces intensities in the 290-320 nm range by roughly 15%. Leaf chlorophyll concentration was determined with a Minolta SPAD-502 chlorophyll meter; the BRAD meter was calibrated with N,N- extractions. Flavonoids were extracted with an acidified methanol/water solution. Soybean grown under the acetate treatment showed 26% smaller internodal lengths and higher concentrations of flavonoids compared to plants grown under mylar. Significant results for alfalfa included 22% greater leaf flavonoid concentration under acetate, 14% greater leaf chlorophyll concentration under mylar, and 32% greater above-ground biomass under mylar. We found that increased UV-B radiation leads to increased production of UV-B absorbing compounds (i.e. flavonoids) in soybean and alfalfa leaves. This suggests that a protective mechanism in these plants is triggered by UV-B. In response, flavonoids are produced that absorb UV-B, and consequently decrease potentially damaging effects to the plants. In addition, we hypothesize that this flavonoid protection mechanism saturates at certain UV-B intensities.

  20. Absorbed radiation doses to staff after implementation of a radiopharmacy clean room.

    PubMed

    Ponto, James A

    2014-12-01

    In response to U.S. Pharmacopeia general chapter <797> standards, a clean room was constructed for our in-house radiopharmacy. Previously, most patient doses were prepared as needed just before injection. Currently, to minimize repeated entries into the clean room, most patient doses are prepared in batches; that is, early morning and noontime preparation of doses to be injected at various times throughout the morning and the afternoon, respectively. Because these patient doses may be prepared well before injection time, radioactive decay necessitates higher amounts of radioactivity to be handled for patient dose preparation. Hence, absorbed radiation doses to staff, all of whom rotate into the radiopharmacy clean room in addition to their regular patient-related activities, were retrospectively evaluated. Monthly dosimetry reports for body (chest badge) and extremities (finger ring) were retrospectively reviewed for each staff member for 12 mo before and 12 mo after implementation of the radiopharmacy clean room. Monthly data were evaluated for average and SD, and 12-mo groups were evaluated using a paired t test. Data for the second 12-mo period were also normalized to the same number of patient doses to account for an increase in procedure volume and were reevaluated. Before the radiopharmacy clean room had been implemented, average monthly absorbed radiation doses to body and extremities were 23 ± 15 mrem (0.23 ± 0.15 mSv) and 93 ± 59 mrem (0.93 ± 0.59 mSv), respectively. After the clean room had been implemented, average monthly absorbed radiation doses increased to 32 ± 16 mrem (0.32 ± 0.16 mSv) (P < 0.001) and 121 ± 89 mrem (1.21 ± 0.89 mSv) (P = 0.0015), respectively. When normalized for procedure volume, average monthly absorbed radiation doses after implementation of the clean room were still higher, at 29 ± 15 mrem (0.29 ± 0.15 mSv) (P = 0.001) and 110 ± 80 mrem (1.10 ± 0.80 mSv) (P = 0.039), respectively. After implementation of a

  1. Photoacoustic Determination of Non-radiative Relaxation Time of Absorbing Centers in Maize Seeds

    NASA Astrophysics Data System (ADS)

    Domínguez-Pacheco, A.; Hernández-Aguilar, C.; Cruz-Orea, A.

    2017-07-01

    Using non-destructive photothermal techniques, it is possible to characterize non-homogenous materials to obtain its optical and thermal properties through photoacoustic spectroscopy (PAS). In photoacoustic (PA) phenomena, there are transient states of thermal excitation, when samples absorb the incident light; these states manifest an excitation process that generates the PA signal, being in direct relation with the non-radiative relaxation times with the sample absorbent centers. The objective of this study was to determine the non-radiative relaxation times associated with different absorbent centers of corn seeds ( Zea mays L.), by using PAS. A frequency scan was done at different wavelengths (350 nm, 470 nm and 650 nm) in order to obtain the non-radiative relaxation times with different types of maize seeds.

  2. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    PubMed

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-06

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

  3. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    PubMed Central

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  4. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    DOE PAGES

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-09-21

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. In this paper, we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. Whenmore » placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Lastly, our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.« less

  5. Comprehensive Expression Profiling and Functional Network Analysis of Porphyra-334, One Mycosporine-Like Amino Acid (MAA), in Human Keratinocyte Exposed with UV-radiation.

    PubMed

    Suh, Sung-Suk; Lee, Sung Gu; Youn, Ui Joung; Han, Se Jong; Kim, Il-Chan; Kim, Sanghee

    2017-06-24

    Mycosporine-like amino acids (MAAs) have been highlighted as pharmacologically active secondary compounds to protect cells from harmful UV-radiation by absorbing its energy. Previous studies have mostly focused on characterizing their physiological properties such as antioxidant activity and osmotic regulation. However, molecular mechanisms underlying their UV-protective capability have not yet been revealed. In the present study, we investigated the expression profiling of porphyra-334-modulated genes or microRNA (miRNAs) in response to UV-exposure and their functional networks, using cDNA and miRNAs microarray. Based on our data, we showed that porphyra-334-regulated genes play essential roles in UV-affected biological processes such as Wnt (Wingless/integrase-1) and Notch pathways which exhibit antagonistic relationship in various biological processes; the UV-repressed genes were in the Wnt signaling pathway, while the activated genes were in the Notch signaling. In addition, porphyra-334-regulated miRNAs can target many genes related with UV-mediated biological processes such as apoptosis, cell proliferation and translational elongation. Notably, we observed that functional roles of the target genes for up-regulated miRNAs are inversely correlated with those for down-regulated miRNAs; the former genes promote apoptosis and translational elongation, whereas the latter function as inhibitors in these processes. Taken together, these data suggest that porphyra-334 protects cells from harmful UV radiation through the comprehensive modulation of expression patterns of genes involved in UV-mediated biological processes, and that provide a new insight to understand its functional molecular networks.

  6. Lipoxin A4 inhibits UV radiation-induced skin inflammation and oxidative stress in mice.

    PubMed

    Martinez, R M; Fattori, V; Saito, P; Melo, C B P; Borghi, S M; Pinto, I C; Bussmann, A J C; Baracat, M M; Georgetti, S R; Verri, W A; Casagrande, R

    2018-04-27

    Lipoxin A4 (LXA 4 ) is a metabolic product of arachidonic acid. Despite potent anti-inflammatory and pro-resolution activities, it remains to be determined if LXA 4 has effect on ultraviolet (UV) radiation-induced skin inflammation. To investigate the effects of systemic administration with LXA 4 on UV radiation-induced inflammation and oxidative damage in the skin of mice. Varied parameters of inflammation and oxidative stress in the skin of mice were evaluated after UV radiation (4.14 J/cm 2 ). Pretreatment with LXA 4 significantly inhibited UV radiation-induced skin edema and myeloperoxidase activity. LXA 4 efficacy was enhanced by increasing the time of pre-treatment to up to 72 h. LXA 4 reduced UV radiation-induced skin edema, neutrophil recruitment (myeloperoxidase activity and LysM-eGFP + cells), MMP-9 activity, deposition of collagen fibers, epidermal thickness, sunburn cell counts, and production of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-33). Depending on the time point, LXA 4 increased the levels of anti-inflammatory cytokines (TGF-β and IL-10). LXA 4 significantly attenuated UV radiation-induced oxidative damage returning the oxidative status to baseline levels in parameters such as ferric reducing ability, scavenging of free radicals, GSH levels, catalase activity and superoxide anion production. LXA 4 also reduced UV radiation-induced gp91 phox [nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) subunit] mRNA expression and enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target enzyme nicotinamide adenine dinucleotide (phosphate) quinone oxidoreductase (Nqo1) mRNA expression. LXA 4 inhibited UV radiation-induced skin inflammation by diminishing pro-inflammatory cytokine production and oxidative stress as well as inducing anti-inflammatory cytokines and Nrf2. Copyright © 2018. Published by Elsevier B.V.

  7. Estimation of UV index in the clear-sky using OMI PROFOZ and AERONET data

    NASA Astrophysics Data System (ADS)

    Lee, H.; Kim, J.; Jeong, U.

    2016-12-01

    Due to a strong influence to the human health and ecosystem environment, continuous monitoring of the surface-level ultraviolet (UV) radiation is important nowadays. UV index (UVI) is a simple parameter to show the strength of surface UV radiation, therefore UVI has been widely utilized for the purpose of UV monitoring. In this work, we also try to develop our own retrieval algorithm for better estimation of UVI. The amount of UVA (320-400 nm) and UVB (290-320 nm) radiation at the Earth surface depends on the extent of Rayleigh scattering by atmospheric gas molecules, the radiative absorption by ozone, radiative scattering by clouds, and both absorption and scattering by airborne aerosols. Thus advanced consideration of these factors is the essential part to establish the process of UVI estimation. In this study, we estimate UV Index (UVI) at Seoul first in a clear-sky atmosphere, and then validate this estimated UVI comparing to UVI from Brewer spectrophotometer measurements located at Yonsei University in Seoul. We use the Vector Linearized Discrete Ordinate Radiative Transfer (VLIDORT) model version 2.6 for our UVI calculation. To consider the ozone and aerosol influence in a real situation, we input ozone and temperature profiles from the Ozone Monitoring Instrument (OMI) Aura vertical profile ozone (PROFOZ) data, and aerosol properties from the AErosol RObotic NETwork (AERONET) measurements at Seoul into the model. Inter-comparison of UVI is performed for the year 2011, 2012 and 2014, and resulted in a high correlation coefficient (R=0.95) under clear-sky condition. But a slight overestimation of Brewer UVI occurred under high AOD conditions in clear-sky. Because our UVI algorithm does not account for surface absorbing aerosols, it is lead to systematic overestimation of surface UV irradiances. Therefore, we also investigate the effect of absorbing aerosol on the amount of UV irradiance in the clear-sky over East Asia.

  8. Coupling Reagent for UV/vis Absorbing Azobenzene-Based Quantitative Analysis of the Extent of Functional Group Immobilization on Silica.

    PubMed

    Choi, Ra-Young; Lee, Chang-Hee; Jun, Chul-Ho

    2018-05-18

    A methallylsilane coupling reagent, containing both a N-hydroxysuccinimidyl(NHS)-ester group and a UV/vis absorbing azobenzene linker undergoes acid-catalyzed immobilization on silica. Analysis of the UV/vis absorption band associated with the azobenzene group in the adduct enables facile quantitative determination of the extent of loading of the NHS groups. Reaction of NHS-groups on the silica surface with amine groups of GOx and rhodamine can be employed to generate enzyme or dye-immobilized silica for quantitative analysis.

  9. Parkin regulates translesion DNA synthesis in response to UV radiation

    PubMed Central

    Huang, Min; Liu, Hongmei; Wang, Fengli; Gong, Juanjuan; Wang, Jiuqiang; Li, Xiaoling; Chen, Qian; Shen, Hongyan; Zhu, Shu; Wang, Yun; Liu, Yang; Guo, Caixia; Tang, Tie-Shan

    2017-01-01

    Deficiency of Parkin is a major cause of early-onset Parkinson's disease (PD). Notably, PD patients also exhibit a significantly higher risk in melanoma and other skin tumors, while the mechanism remains largely unknown. In this study, we show that depletion of Parkin causes compromised cell viability and genome stability after ultraviolet (UV) radiation. We demonstrate that Parkin promotes efficient Rad18-dependent proliferating cell nuclear antigen (PCNA) monoubiquitination by facilitating the formation of Replication protein A (RPA)-coated ssDNA upon UV radiation. Furthermore, Parkin is found to physically interact with NBS1 (Nijmegen breakage syndrome 1), and to be required for optimal recruitment of NBS1 and DNA polymerase eta (Polη) to UV-induced damage sites. Consequently, depletion of Parkin leads to increased UV-induced mutagenesis. These findings unveil an important role of Parkin in protecting genome stability through positively regulating translesion DNA synthesis (TLS) upon UV damage, providing a novel mechanistic link between Parkin deficiency and predisposition to skin cancers in PD patients. PMID:28430587

  10. Absorbing Aerosols Above Cloud: Detection, Quantitative Retrieval, and Radiative Forcing from Satellite-based Passive Sensors

    NASA Astrophysics Data System (ADS)

    Jethva, H.; Torres, O.; Remer, L. A.; Bhartia, P. K.

    2012-12-01

    Light absorbing particles such as carbonaceous aerosols generated from biomass burning activities and windblown dust particles can exert a net warming effect on climate; the strength of which depends on the absorption capacity of the particles and brightness of the underlying reflecting background. When advected over low-level bright clouds, these aerosols absorb the cloud reflected radiation from ultra-violet (UV) to shortwave-IR (SWIR) and makes cloud scene darker-a phenomenon commonly known as "cloud darkening". The apparent "darkening" effect can be seen by eyes in satellite images as well as quantitatively in the spectral reflectance measurements made by space borne sensors over regions where light absorbing carbonaceous and dust aerosols overlay low-level cloud decks. Theoretical radiative transfer simulations support the observational evidence, and further reveal that the strength of the cloud darkening and its spectral signature (or color ratio) between measurements at two wavelengths are a bi-function of aerosol and cloud optical thickness (AOT and COT); both are measures of the total amount of light extinction caused by aerosols and cloud, respectively. Here, we developed a retrieval technique, named as the "color ratio method" that uses the satellite measurements at two channels, one at shorter wavelength in the visible and one at longer wavelength in the shortwave-IR for the simultaneous retrieval of AOT and COT. The present technique requires assumptions on the aerosol single-scattering albedo and aerosol-cloud separation which are supplemented by the Aerosol Robotic Network (AERONET) and space borne CALIOP lidar measurements. The retrieval technique has been tested making use of the near-UV and visible reflectance observations made by the Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) for distinct above-cloud smoke and dust aerosol events observed seasonally over the southeast and tropical Atlantic Ocean

  11. Efficiency of ocular UV protection by clear lenses

    PubMed Central

    Rifai, Katharina; Hornauer, Matthias; Buechinger, Ramona; Schoen, Roland; Barraza-Bernal, Maria; Habtegiorgis, Selam; Glasenapp, Carsten; Wahl, Siegfried; Mappes, Timo

    2018-01-01

    Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario. PMID:29675331

  12. Efficiency of ocular UV protection by clear lenses.

    PubMed

    Rifai, Katharina; Hornauer, Matthias; Buechinger, Ramona; Schoen, Roland; Barraza-Bernal, Maria; Habtegiorgis, Selam; Glasenapp, Carsten; Wahl, Siegfried; Mappes, Timo

    2018-04-01

    Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario.

  13. Method 415.3, Rev. 1.2: Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water

    EPA Science Inventory

    This method provides procedures for the determination of total organic carbon (TOC), dissolved organic carbon (DOC), and UV absorption at 254 nm (UVA) in source waters and drinking waters. The DOC and UVA determinations are used in the calculation of the Specific UV Absorbance (S...

  14. Experimental study of acoustic radiation force of an ultrasound beam on absorbing and scattering objects

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nikolaeva, Anastasiia V., E-mail: niko200707@mail.ru; Kryzhanovsky, Maxim A.; Tsysar, Sergey A.

    Acoustic radiation force is a nonlinear acoustic effect caused by the transfer of wave momentum to absorbing or scattering objects. This phenomenon is exploited in modern ultrasound metrology for measurement of the acoustic power radiated by a source and is used for both therapeutic and diagnostic sources in medical applications. To calculate radiation force an acoustic hologram can be used in conjunction with analytical expressions based on the angular spectrum of the measured field. The results of an experimental investigation of radiation forces in two different cases are presented in this paper. In one case, the radiation force of anmore » obliquely incident ultrasound beam on a large absorber (which completely absorbs the beam) is considered. The second case concerns measurement of the radiation force on a spherical target that is small compared to the beam diameter.« less

  15. Thermally Resilient, Broadband Optical Absorber from UV to IR Derived from Carbon Nanostructures

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Coles, James B.

    2012-01-01

    electric field inherent in a plasma yields vertically aligned CNTs at small length scales (less than 10 m), which still exhibit broadband, and high-efficiency optical absorption characteristics from the ultraviolet (UV) to IR. A thin and yet highly absorbing coating is extremely valuable for detector applications for radiometry in order to enhance sensitivity. A plasma-based process also increases the potential of forming the optical absorbers at lower synthesis temperatures in the future, increasing the prospects of integrating the absorbers with flexible substrates for low-cost solar cell applications, for example.

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

    NASA Astrophysics Data System (ADS)

    Chen, Maosi

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  18. Simulation of the UV-radiation at the Martian surface

    NASA Astrophysics Data System (ADS)

    Kolb, C.; Stimpfl, P.; Krenn, H.; Lammer, H.; Kargl, G.; Abart, R.; Patel, M. R.

    The UV-radiation at the Martian surface is for several reasons of importance. UV radiation can cause specific damages in the DNA-containing living systems and is involved in the formation of catalytically produced oxidants such as superoxide ions and peroxides. These are capable to oxidize and subsequently destroy organic matter. Lab simulations are necessary to investigate and understand the effects of organic matter removal at the Martian surface. We designed a radiation apparatus which simulates the solar spectrum at the Martian surface between 200 and 700 nm. The system consists of an UV-enhanced xenon arc lamp and special exchangeable filter-sets and mirrors for simulating the effects of the Martian atmospheric column and dust loading. A special collimating system bundles the final parallel beam so that the intensity at the target spot is independent from the distance between the ray source and the sample. The system was calibrated by means of an optical photo-spectrometer to align the ray output with the theoretical target spectrum and to ensure spectral homogeneity. We present preliminary data on calibration and performance of our system, which is integrated in the Austrian Mars simulation facility.

  19. Responses of Crepis japonica induced by supplemental blue light and UV-A radiation.

    PubMed

    Constantino, L F da S; Nascimento, L B Dos S; Casanova, L M; Moreira, N Dos S; Menezes, E A; Esteves, R L; Costa, S S; Tavares, E S

    2017-02-15

    Crepis japonica (L.) D.C. (Asteraceae), a weed with antioxidant, antiallergenic, antiviral and antitumor properties displays both medicinal properties and nutritional value. This study aims to assess the effects of a supplementation of blue light and UV-A radiation on the growth, leaf anatomical structure and phenolic profile of the aerial parts of Crepis japonica. Plants were grown under two light treatments: W (control - white light), W + B (white light supplemented with blue light) and W + UV-A (white light supplemented with UV-A radiation). We recorded the length, width, and weight of fresh and dry leaves, the thickness of the epidermis and mesophyll, and stomata density. The phenolic profiles of the aqueous extracts of the aerial parts were analyzed by HPLC-DAD. There was an increase in the leaf size, stomatal density, and phenolic production, and a thickening of the mesophyll and epidermis. UV-A radiation increased the phenolic production more than blue light. Blue light and UV-A radiation both improved the production of caffeic acid by about 6 and 3 times, respectively, in comparison to control. This compound was first reported as a constituent of the extract from the aerial parts together with caftaric acid. UV-A also promoted the production of chlorogenic acid (about 1.5 times in comparison to the control). We observed that the morphological and chemical parameters of C. japonica are modified in response to blue light and UV-A radiation, which can be used as tools in the cultivation of this species in order to improve its medicinal properties and nutritional value.

  20. Cytoprotective effect against UV-induced DNA damage and oxidative stress: role of new biological UV filter.

    PubMed

    Said, T; Dutot, M; Martin, C; Beaudeux, J-L; Boucher, C; Enee, E; Baudouin, C; Warnet, J-M; Rat, P

    2007-03-01

    The majority of chemical solar filters are cytotoxic, particularly on sensitive ocular cells (corneal and conjunctival cells). Consequently, a non-cytotoxic UV filter would be interesting in dermatology, but more especially in ophthalmology. In fact, light damage to the eye can be avoided thanks to a very efficient ocular antioxidant system; indeed, the chromophores absorb light and dissipate its energy. After middle age, a decrease in the production of antioxidants and antioxidative enzymes appears with accumulation of endogenous molecules that are phototoxic. UV radiations can induce reactive oxygen species formation, leading to various ocular diseases. Because most UV filters are cytotoxic for the eye, we investigated the anti-UV properties of Calophyllum inophyllum oil in order to propose it as a potential vehicle, free of toxicity, with a natural UV filter action in ophthalmic formulation. Calophyllum inophyllum oil, even at low concentration (1/10,000, v/v), exhibited significant UV absorption properties (maximum at 300nm) and was associated with an important sun protection factor (18-22). Oil concentrations up to 1% were not cytotoxic on human conjunctival epithelial cells, and Calophyllum inophyllum oil appeared to act as a cytoprotective agent against oxidative stress and DNA damage (85% of the DNA damage induced by UV radiations were inhibited with 1% Calophyllum oil) and did not induce in vivo ocular irritation (Draize test on New Zealand rabbits). Calophyllum inophyllum oil thus exhibited antioxidant and cytoprotective properties, and therefore might serve, for the first time, as a natural UV filter in ophthalmic preparations.

  1. Towards standardization of UV eye protection: what can be learned from photodermatology?

    PubMed

    Krutmann, Jean; Béhar-Cohen, Francine; Baillet, Gilles; de Ayguavives, Tito; Ortega Garcia, Paula; Peña-García, Pablo; Remé, Charlotte; Wolffsohn, James

    2014-01-01

    While knowledge about standardization of skin protection against ultraviolet radiation (UVR) has progressed over the past few decades, there is no uniform and generally accepted standardized measurement for UV eye protection. The literature provides solid evidence that UV can induce considerable damage to structures of the eye. As well as damaging the eyelids and periorbital skin, chronic UV exposure may also affect the conjunctiva and lens. Clinically, this damage can manifest as skin cancer and premature skin ageing as well as the development of pterygia and premature cortical cataracts. Modern eye protection, used daily, offers the opportunity to prevent these adverse sequelae of lifelong UV exposure. A standardized, reliable and comprehensive label for consumers and professionals is currently lacking. In this review we (i) summarize the existing literature about UV radiation-induced damage to the eye and surrounding skin; (ii) review the recent technological advances in UV protection by means of lenses; (iii) review the definition of the Eye-Sun Protection Factor (E-SPF®), which describes the intrinsic UV protection properties of lenses and lens coating materials based on their capacity to absorb or reflect UV radiation; and (iv) propose a strategy for establishing the biological relevance of the E-SPF. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

    2011-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  3. Atlas of albedo and absorbed solar radiation derived from Nimbus 7 earth radiation budget data set, November 1985 to October 1987

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Rutan, David; Bess, T. Dale

    1992-01-01

    An atlas of monthly mean global contour maps of albedo and absorbed solar radiation is presented for 21 months from Nov. 1985 to Oct. 1987. These data were retrieved from measurements made by the shortwave wide-field-of-view radiometer of the Earth Radiation Budget (ERB) instrument aboard the Nimbus 7 spacecraft. Profiles of zonal mean albedos and absorbed solar radiation were tabulated. These geographical distributions are provided as a resource for researchers studying the radiation budget of the Earth. The El Nino/Southern Oscillation event of 1986-1987 is included in this data set. This atlas of albedo and absorbed solar radiation extends to 12 years the period covered by two similar atlases: NASA RP-1230 (Jul. 1975 - Oct. 1978) and NASA RP-1231 (Nov. 1978 - Oct. 1985). These three compilations complement the atlases of outgoing longwave radiation by Bess and Smith in NASA RP-1185, RP-1186, and RP-1261, which were also based on the Nimbus 6 and 7 ERB data.

  4. Effects of solar UV radiation and climate change on biogeochemical cycling: interactions and feedbacks.

    PubMed

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

    2011-02-01

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions of these effects with climate change, including feedbacks on climate. Such interactions occur in both terrestrial and aquatic ecosystems. While there is significant uncertainty in the quantification of these effects, they could accelerate the rate of atmospheric CO(2) increase and subsequent climate change beyond current predictions. The effects of predicted changes in climate and solar UV radiation on carbon cycling in terrestrial and aquatic ecosystems are expected to vary significantly between regions. The balance of positive and negative effects on terrestrial carbon cycling remains uncertain, but the interactions between UV radiation and climate change are likely to contribute to decreasing sink strength in many oceanic regions. Interactions between climate and solar UV radiation will affect cycling of elements other than carbon, and so will influence the concentration of greenhouse and ozone-depleting gases. For example, increases in oxygen-deficient regions of the ocean caused by climate change are projected to enhance the emissions of nitrous oxide, an important greenhouse and ozone-depleting gas. Future changes in UV-induced transformations of aquatic and terrestrial contaminants could have both beneficial and adverse effects. Taken in total, it is clear that the future changes in UV radiation coupled with human-caused global change will have large impacts on biogeochemical cycles at local, regional and global scales.

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

    PubMed

    Formánek, Pavel; Rejšek, Klement; Vranová, Valerie

    2014-01-01

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

  6. Novel radiator for carbon dioxide absorbents in low-flow anesthesia.

    PubMed

    Hirabayashi, Go; Mitsui, Takanori; Kakinuma, Takayasu; Ogihara, Yukihiko; Matsumoto, Shohei; Isshiki, Atsushi; Yasuo, Watanabe

    2003-01-01

    During long-term low-flow sevoflurane anesthesia, dew formation and the generation of compound A are increased in the anesthesia circuit because of elevated soda lime temperature. The object of this study was to develop a novel radiator for carbon dioxide absorbents used for long durations of low-flow sevoflurane anesthesia. Eleven female swine were divided into two groups comprising a "radiator" group (n = 5) that used a novel radiator for carbon dioxide absorbents and a "control" group (n = 6) that used a conventional canister. Anesthesia was maintained with N2O, O2, and sevoflurane, and low-flow anesthesia was performed with fresh gas flow at 0.6 L/min for 12 hr. In the "control" group, the soda lime temperature reached more than 40 degrees C and soda lime dried up with severe dew formation in the inspiratory valve. In the "radiator" group, the temperature of soda lime stayed at 30 degrees C, and the water content of soda lime was retained with no dew formation in the inspiratory valve. In addition, compound A concentration was reduced. In conclusion, radiation of soda lime reduced the amounts of condensation formed and the concentration of compound A in the anesthetic circuit, and allowed long term low-flow anesthesia without equipment malfunction.

  7. Heavy-ion-induced sucrose radicals investigated using EPR and UV spectroscopy

    PubMed Central

    Nakagawa, Kouichi; Karakirova, Yordanka; Yordanov, Nicola D.

    2015-01-01

    The potential use of a sucrose dosimeter for estimating both linear energy transfer (LET) and the absorbed dose of heavy ion and X-ray radiation was investigated. The stable free radicals were produced when sucrose was irradiated with heavy ions, such as helium, carbon, silicon and neon ions, and when the X-ray radiation was similar to the obtained electron paramagnetic resonance (EPR) spectra, which were ∼7 mT wide and composed of several hyperfine structures. In addition, the total spin concentration resulting from heavy-ion irradiation increased linearly as the absorbed dose increased, and decreased logarithmically as the LET increased. These empirical relations imply that the LET at a certain dose can be determined from the spin concentration. For sucrose and alanine, both cross-sections following C-ion irradiation with a 50 Gy dose were ∼1.3 × 10−12 [μm2], taking into account the molecular size of the samples. The values of these cross-sections imply that multiple ionizing particles were involved in the production of stable radicals. Furthermore, UV absorbance at 267 nm of an aqueous solution of irradiated sucrose was found to linearly increase with increasing absorbed dose. Therefore, the EPR and UV results suggest that sucrose can be a useful dosimeter for heavy-ion irradiation. PMID:25480828

  8. Effects of UV-B radiation on the isoflavone accumulation and physiological-biochemical changes of soybean during germination: Physiological-biochemical change of germinated soybean induced by UV-B.

    PubMed

    Ma, Meng; Wang, Pei; Yang, Runqiang; Gu, Zhenxin

    2018-06-01

    In this study, the effects of UV-B radiation on the isoflavones accumulation, physiological and nutritional quality, water status, and characteristics of proteins in germinated soybeans were investigated. The results showed that isoflavones content in soybeans increased with appropriate intensity and time of UV-B radiation and decreased with excessive treatment. Fresh weight, length, free amino acids, reducing sugar contents and bulk water (T 23 ) in germinated soybeans decreased with increasing radiation time, indicating that UV-B inhibited the growth and nutrients metabolism of soybean during germination. Cell damage was detected in germinated soybeans with excessive UV-B radiation, as shown by the black spots in cotyledons and the increased intercellular water determined by LF-NMR. Germination resulted in an increase in random coil structures, while UV-B radiation induced no obvious changes in FT-IR spectrum and protein conformation of soybeans. Both UV-B radiation and germination caused the increase in soluble proteins, especially in 1.0-75.0 kDa fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Structural, energetic, and UV-Vis spectral analysis of UVA filter 4-tert-butyl-4'-methoxydibenzoylmethane.

    PubMed

    Pinto da Silva, Luís; Ferreira, Paulo J O; Duarte, Darío J R; Miranda, Margarida S; Esteves da Silva, Joaquim C G

    2014-02-27

    The growing awareness of the harmful effects of ultraviolet (UV) solar radiation has increased the production and consumption of sunscreen products, which contain organic and inorganic molecules named UV filters that absorb, reflect, or scatter UV radiation, thus minimizing negative human health effects. 4-tert-Butyl-4'-methoxydibenzoylmethane (BMDBM) is one of the few organic UVA filters and the most commonly used. BMDBM exists in sunscreens in the enol form which absorbs strongly in the UVA range. However, under sunlight irradiation tautomerization occurs to the keto form, resulting in the loss of UV protection. In this study we have performed quantum chemical calculations to study the excited-state molecular structure and excitation spectra of the enol and keto tautomers of BMDBM. This knowledge is of the utmost importance as the starting point for studies aiming at the understanding of its activity when applied on human skin and also its fate once released into the aquatic environment. The efficiency of excitation transitions was rationalized based on the concept of molecular orbital superposition. The loss of UV protection was attributed to the enol → keto phototautomerism and subsequent photodegradation. Although this process is not energetically favorable in the singlet bright state, photodegradation is possible because of intersystem crossing to the first two triplet states.

  10. Observations of the diffuse UV radiation field

    NASA Technical Reports Server (NTRS)

    Murthy, Jayant; Henry, R. C.; Feldman, P. D.; Tennyson, P. D.

    1989-01-01

    Spectra are presented for the diffuse UV radiation field between 1250 to 3100 A from eight different regions of the sky, which were obtained with the Johns Hopkins UVX experiment. UVX flew aboard the Space Shuttle Columbia (STS-61C) in January 1986 as part of the Get-Away Special project. The experiment consisted of two 1/4 m Ebert-Fastie spectrometers, covering the spectral range 1250 to 1700 A at 17 A resolution and 1600 to 3100 A at 27 A resolution, respectively, with a field of view of 4 x .25 deg, sufficiently small to pick out regions of the sky with no stars in the line of sight. Values were found for the diffuse cosmic background ranging in intensity from 300 to 900 photons/sq cm/sec/sr/A. The cosmic background is spectrally flat from 1250 to 3100 A, within the uncertainties of each spectrometer. The zodiacal light begins to play a significant role in the diffuse radiation field above 2000 A, and its brightness was determined relative to the solar emission. Observed brightnesses of the zodiacal light in the UV remain almost constant with ecliptic latitude, unlike the declining visible brightnesses, possibly indicating that those (smaller) grains responsible for the UV scattering have a much more uniform distribution with distance from the ecliptic plane than do those grains responsible for the visible scattering.

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

    PubMed

    Rivas, F J; Gimeno, O; Borralho, T; Carbajo, M

    2010-07-15

    The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H(2)O(2), UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO(2), UV-C/H(2)O(2)/TiO(2) and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5x10(-3) mol Einstein(-1) at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate. Mineralization degree was negligible when no promoter was added, while low values were achieved in the presence of either inorganic peroxides or titanium dioxide. The combination of radiation, hydrogen peroxide and TiO(2) increased the mineralization level up to values in the proximity of 45-50% under the best conditions investigated. The photo-Fenton process was the best system in terms of total oxidation (mineralization degree 70%) when optimum conditions were applied. 2010 Elsevier B.V. All rights reserved.

  12. Ultraviolet Radiations: Skin Defense-Damage Mechanism.

    PubMed

    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.

  13. Effects of UV-B radiation on phenolic composition and deposition patterns and leaf physiology in three Eastern tree species

    NASA Astrophysics Data System (ADS)

    Sullivan, Joseph H.; Gitz, Dennis C.; Peek, Michael S.; McElrone, Andrew J.

    2002-01-01

    Quantitative changes in foliar chemistry in response to UVB radiation are frequently reported but less is known about the qualitative changes in putative UV-screening compounds. It has also not been conclusively shown whether qualitative differences in screening compounds or differences in localization patterns influences the sensitivity of plants to damage from UVB radiation. In this study we evaluated the chemical composition and deposition patterns of UV-absorbing compounds in three tree species and assayed these species for possible effects on gas exchange and photosynthetic carbon assimilation. Branches of mature trees of sweetgum (Liquidambar styraciflua), tulip poplar (Liriodendron tulipifera) and red maple (Acer rubrum) were exposed to supplemental levels of UVB radiation over three growing seasons. Controls for UVA were also measured by exposing branches to supplemental UVA only, and additional branches not irradiated were also used for controls. These species demonstrated contrasting chemical composition and deposition patterns with poplar being the most responsive in terms of epidermal accumulation of phenolics including flavonols and chlorogenic acid and hydroxycinnamates. Sweetgum and red maple showed increases primarily in hydroxycinnamates, particularly in the mesophyll in red maple. Leaf area was marginally influenced by UV exposure level. Assimilation was generally not reduced by UVB radiation in these species and was enhanced in red maple by both UVB and UVA and by UVA in sweetgum. These finding are consistent with a hypothesis that epidermal attenuation of UVB would only be reduced in poplar, which accumulated the additional epidermal screening compounds. It is possible that photosynthetic efficiency was enhanced in red maple by the increased absorption of blue light within the mesophyll. Stomatal conductance was generally reduced, and this led to an increase in water use efficiency in red maple and poplar.

  14. A flavonoid from Brassica rapa flower as the UV-absorbing nectar guide.

    PubMed

    Sasaki, Katsunori; Takahashi, Takashi

    2002-10-01

    The corolla of Brassica rapa has an UV-absorbing zone in its center, known as the nectar guide for attracting pollinating insects. The pigment which plays the role of the nectar guide was isolated from the petals and identified to be isorhamnetin 3,7-O-di-beta-D-glucopyranoside on the basis of MS and NMR spectroscopic data. The D-, L-configurations of the sugar moieties were determined by the fluorometric HPLC method. In plants raised in open field, there was a 13-fold higher content of the compound in the basal parts of the petals compared with the apical parts. This difference in flavonoid content is presumed to contribute to the visual attractiveness of B. rapa flowers to insect pollinators.

  15. Modeling UV Radiation Feedback from Massive Stars. II. Dispersal of Star-forming Giant Molecular Clouds by Photoionization and Radiation Pressure

    NASA Astrophysics Data System (ADS)

    Kim, Jeong-Gyu; Kim, Woong-Tae; Ostriker, Eve C.

    2018-05-01

    UV radiation feedback from young massive stars plays a key role in the evolution of giant molecular clouds (GMCs) by photoevaporating and ejecting the surrounding gas. We conduct a suite of radiation hydrodynamic simulations of star cluster formation in marginally bound, turbulent GMCs, focusing on the effects of photoionization and radiation pressure on regulating the net star formation efficiency (SFE) and cloud lifetime. We find that the net SFE depends primarily on the initial gas surface density, Σ0, such that the SFE increases from 4% to 51% as Σ0 increases from 13 to 1300 {M}ȯ {pc}}-2. Cloud destruction occurs within 2–10 Myr after the onset of radiation feedback, or within 0.6–4.1 freefall times (increasing with Σ0). Photoevaporation dominates the mass loss in massive, low surface density clouds, but because most photons are absorbed in an ionization-bounded Strömgren volume, the photoevaporated gas fraction is proportional to the square root of the SFE. The measured momentum injection due to thermal and radiation pressure forces is proportional to {{{Σ }}}0-0.74, and the ejection of neutrals substantially contributes to the disruption of low mass and/or high surface density clouds. We present semi-analytic models for cloud dispersal mediated by photoevaporation and by dynamical mass ejection, and show that the predicted net SFE and mass loss efficiencies are consistent with the results of our numerical simulations.

  16. Development of absorbing aerosol index simulator based on TM5-M7

    NASA Astrophysics Data System (ADS)

    Sun, Jiyunting; van Velthoven, Peter; Veefkind, Pepijn

    2017-04-01

    Aerosols alter the Earth's radiation budget directly by scattering and absorbing solar and thermal radiation, or indirectly by perturbing clouds formation and lifetime. These mechanisms offset the positive radiative forcing ascribed to greenhouse gases. In particular, absorbing aerosols such as black carbon and dust strongly enhance global warming. To quantify the impact of absorbing aerosol on global radiative forcing is challenging. In spite of wide spatial and temporal coverage space-borne instruments (we will use the Ozone Monitoring Instrument, OMI) are unable to derive complete information on aerosol distribution, composition, etc. The retrieval of aerosol optical properties also partly depends on additional information derived from other measurements or global atmospheric chemistry models. Common quantities of great interest presenting the amount of absorbing aerosol are AAOD (absorbing aerosol optical depth), the extinction due to absorption of aerosols under cloud free conditions; and AAI (absorbing aerosol index), a measure of aerosol absorption more directly derivable from UV band observations than AAOD. When comparing model simulations and satellite observations, resemblance is good in terms of the spatial distribution of both parameters. However, the quantitative discrepancy is considerable, indicating possible underestimates of simulated AAI by a factor of 2 to 3. Our research, hence, has started by evaluating to what extent aerosol models, such as our TM5-M7 model, represent the satellite measurements and by identifying the reasons for discrepancies. As a next step a transparent methodology for the comparison between model simulations and satellite observations is under development in the form of an AAI simulator based on TM5-M7.

  17. Replicated mesocosm study on the role of natural ultraviolet radiation in high CDOM, shallow lakes.

    PubMed

    Pérez, A Patricia; Diaz, Mónica M; Ferraro, Marcela A; Cusminsky, Gabriela C; Zagarese, Horacio E

    2003-02-01

    The role of ultraviolet radiation on shallow, high CDOM (colored dissolved organic matter) lakes was investigated during two consecutive summers (1999 and 2000) in replicated mesocosms (rectangular fiberglass tanks). Each tank (volume: 300 L; depth: 40 cm) was covered with a layer (approximately 3 cm) of sediment from lake El Toro (40 degrees 14' S; 70 degrees 22' W) and filled with filtered water. The experimental design consisted of two treatments: full natural radiation (UV-exposed) and natural radiation without ultraviolet radiation (UV-shielded). UV-exposed and UV-shielded treatments differed in most studied variables as revealed by repeated measures ANOVA. UV-exposed tanks displayed lower CDOM levels (dissolved absorbance) of lower average molecular size (absorbance ratio between 250 and 365 nm), higher bacterial biomass, and lower chlorophyll a concentration. The effect on consumers (rotifers and crustaceans) was less noticeable. The results are consistent with UV stimulation of bacteria production mediated by higher rates of CDOM photobleaching, and the photoinhibition of planktonic algae. Thus, a major effect of UVR in shallow, high CDOM ecosystems appears to be the stimulation of heterotrophic pathways and a simultaneous inhibition of photoautotrophs.

  18. Role of near ultraviolet wavelength measurements in the detection and retrieval of absorbing aerosols from space

    NASA Astrophysics Data System (ADS)

    Mukai, Sonoyo; Fujito, Toshiyuki; Nakata, Makiko; Sano, Itaru

    2017-10-01

    Aerosol remote sensing by ultraviolet (UV) wavelength is established by a Total Ozone Mapping Spectrometer (TOMS) mounted on the long-life satellite Nimbus-7 and continues to make observations using Ozone monitoring instrument (OMI) located on the Aura satellite. For example, TOMS demonstrated that UV radiation (0.331 and 0.360 μm) could easily detect absorbing particles such as mineral dust or smoke aerosols. TOMS-AI (absorbing aerosol index) has been used to identify the absorbing aerosols from space. For an upcoming mission, JAXA/GCOM-C will have the polarization sensor SGLI boarded in December 2017. The SGLI has multi (19)-channels including near UV (0.380 μm) and violet (0.412 μm) wavelengths. This work intends to examine the role of near UV data in the detection of absorbing aerosols similar to TOMS-AI played. In practice, the measurements by GLI mounted on the short Japanese mission JAXA/ADEOS-2, whose data archive period was just 8 months from April to October in 2003, are available for simulation of SGLI data because ADEOS-2/GLI installed near UV and violet channels. First of all, the ratio of data at 0.412 μm to that at 0.380 μm is examined as an indicator to detect absorbing aerosols on a global scale during ADEOS-2 era. It is noted that our research group has developed an efficient algorithm for aerosol retrieval in hazy episodes (dense concentrations of atmospheric aerosols). It can be said that at least this work is an attempt to grasp the biomass burning plumes from the satellite.

  19. Electromagnetic radiation absorbers and modulators comprising polyaniline

    DOEpatents

    Epstein, Arthur J.; Ginder, John M.; Roe, Mitchell G.; Hajiseyedjavadi, Hamid

    1992-01-01

    A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

  20. Radiation Sensitivity of Soluble Polysilane Derivatives: Science and Applications

    DTIC Science & Technology

    1988-08-01

    sigma bonded, all substituted silane polymers absorb strongly in the UV-visible region. Their absorption spectra depend to some extent on the nature...of the substituents. In this regard alkyl substituted, atatic, amphorous materials absorb from 300-325 nm with sterically bulky groups producing a...cases, the polysilane is the primary absorber of the incident radiation. Interestingly, when 3, which absorbs at -400 inm, was incorporated into a film

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

    EPA Science Inventory

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

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

    PubMed Central

    Rejšek, Klement; Vranová, Valerie

    2014-01-01

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

  3. Aqueous Chemistry in the Clouds of Venus: A Possible Source for the UV Absorber

    NASA Astrophysics Data System (ADS)

    Baines, Kevin H.; Delitsky, M. L.

    2013-10-01

    The identity and cause of the UV absorber near the Venusian cloudtops 62-70 km altitude) has been an enduring mystery. Given the role of sulfur in Venus’s atmosphere, where, somewhat analogous to water on Earth, it cycles through gas, liquid, and (possibly) solid phases in the atmosphere, it has been a prime suspect as at least a key component, perhaps as long-lived solid poly-sulfur aerosols, Sn, where n > 4. However, the narrow range of altitudes inhabited by the UV absorber (thought to form and reside primarily above 62 km altitude) seems incompatible with Sn, which should vertically disperse after formation. Here, we point to another process that could lead to somewhat more exotic chemistries that favor formation and sequestration at high altitudes: Aqueous chemistry within H2SO4-nH2O cloud particles. Due to (1) the decrease of temperature and (2) the increase in the fraction of water (“n” in the previous formula) of each cloud droplet with altitude, high-altitude particles near the cloudtops are - via the “heterogeneous uptake” process - significantly more capable of capturing and concentrating trace gases, in particular HCl. For example, the heterogeneous uptake of HCl in H2SO4 droplets near the 65-km cloudtops is at least three times greater than that found in the middle of the clouds near 55 km altitude. Other factors such as local mixing ratios and the concentration of other solvents in the droplet also modify the uptake. Within the cloud droplets, solution chemistry between HCl and H2SO4 may lead to the formation of chlorosulfonic acid, ClSO3H, which is a weak acid that readily breaks down into other species, such as SO2Cl2 (sulfuryl chloride) and SOCl2 (thionyl chloride). Together, these three materials have UV-blue absorptions at 0.21, 0.29, 0.39 and 0.47 micron. Thus, H2SO4 aerosols at high altitudes may take on lasting UV absorption characteristics, dependent on temperature (altitude) and other conditions, Balloons floating at benign Earth

  4. Diurnal changes in CN metabolism and response of rice seedlings to UV-B radiation.

    PubMed

    Yun, Hyejin; Lim, Sunhyung; Kim, Yangmin X; Lee, Yejin; Lee, Seulbi; Lee, Deogbae; Park, Keewoong; Sung, Jwakyung

    2018-03-13

    Plants regulate a number of primary metabolites, including carbohydrates, organic acids, and amino acids, in response to UV-B radiation. Therefore, it is essential to understand the time-dependent response of rice plants to UV-B stress. This study focused on the response of plants to UV-B at different leaf developmental phases (emerging, growing, and maturing) in an attempt to fully comprehend the metabolic shift. We analyzed the expression levels of genes related to starch/sucrose metabolism in the leaf blades of rice seedlings (Oryza sativa L. "Saechuchenog") exposed to UV-B irradiation for short (1 day) and long terms (5 days) using quantitative real-time polymerase chain reaction. We also examined the diurnal variations in the contents of primary metabolites using an established GCTOF-MS (gas chromatography time of flight-mass spectrometry) method. The results showed that the levels of primary metabolites were largely dependent upon the diurnal rhythm and leaf developmental phase. The young leaves (sink) produced and accumulated starch rather than sucrose. The short-term (4 h, 1 day) UV-B exposure inhibited sucrose synthesis, which could be the first target of UV-B radiation. Following short- and long-term (5 days) exposure to UV-B radiation, the dynamic response of primary metabolites was evaluated. It was found that the content of carbohydrates decreased throughout the period of exposure to UV-B stress, especially in terms of sucrose concentration. However, the content of the majority of amino acids increased after an early decrease. Our data revealed that the metabolic response, as well as the gene expression, differed with the period (intensity) of exposure to UV-B radiation and with the phase of leaf development. These findings provide new insights for a better understanding of the metabolic response of a variety of plant species exposed to a wide range of UV-B radiation. Copyright © 2018. Published by Elsevier GmbH.

  5. Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure

    PubMed Central

    Premi, Sanjay; Wallisch, Silvia; Mano, Camila M.; Weiner, Adam B.; Bacchiocchi, Antonella; Wakamatsu, Kazumasa; Bechara, Etelvino J. H.; Halaban, Ruth; Douki, Thierry; Brash, Douglas E.

    2015-01-01

    Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPD), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. Here we show that in melanocytes, CPD are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These “dark CPD” constitute the majority of CPD and include the cytosine-containing CPD that initiate UV-signature C→T mutations. Dark CPD arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but that induces CPD by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically-generated excited electronic states are relevant to mammalian biology. PMID:25700512

  6. Two years comparative studies on biological effects of environmental UV radiation

    NASA Astrophysics Data System (ADS)

    Grof, P.; Ronto, Gyorgyi; Gaspar, S.; Berces, A.; Szabo, Laszlo D.

    1994-07-01

    A method has been developed for determination of the biologically effective UV dose based on T7 phage as biosensor. In field experiments clockwork driven telescope has been used for determining doses from direct and global (direct plus diffuse) solar radiation. On fine summer days at mid-latitude this arrangement allowed the following comparisons: measured doses from direct and global radiation obtained at the same time and measuring site reflecting the biological importance of diffuse radiation; direct and global radiation obtained at the same time and measuring site reflecting the biological importance of diffuse radiation; direct and global doses obtained at the same time on different measuring sites (downtown, suburb, outside the town) reflecting the differences caused by air quality; direct and global doses obtained on the same measuring place, in summertime of two different years reflecting the importance of the long-term measurements for estimating the biological risk caused by increased UV-B radiation; measured data and model calculations.

  7. Fingerprinting Dissolved Organic Carbon (DOC) Sources with Specific UV Absorbance (SUVA) and Fluorescence

    NASA Astrophysics Data System (ADS)

    van Verseveld, W. J.; Lajtha, K.; McDonnell, J. J.

    2007-12-01

    DOC is an important water quality constituent because it is an important food source for stream biota, it plays a significant role in metal toxicity and transport, and protects aquatic organisms by absorbing visible and UV light. However, sources of stream DOC and changes in DOC quality at storm and seasonal scales remain poorly understood. We characterized DOC concentrations and SUVA (as an indicator of aromaticity) at the plot, hillslope and catchment scale during and between five storm events over the period Fall 2004 until Spring 2005, in WS10, H.J. Andrews, Oregon, USA. This study site has hillslopes that issue directly into the stream. This enabled us to compare a trenched hillslope response to the stream response without the influence of a riparian zone. The main result of this study was that SUVA in addition to DOC was needed to fingerprint sources of DOC. Stream water and lateral subsurface flow showed a clockwise DOC and SUVA hysteresis pattern. Both organic horizon water and transient groundwater were characterized by high DOC concentrations and SUVA values, while DOC concentrations and SUVA values in soil water decreased with depth in the soil profile. This indicates transient groundwater was an important contributor to high DOC concentrations and SUVA values during storm events. During the falling limb of the hydrograph deep soil water and seepage groundwater based on SUVA values contributed significantly to lateral subsurface flow and stream water. Preliminary results showed that fluorescence of stream water and lateral subsurface flow continuously measured with a fluorometer was significantly related to UV-absorbance during a December storm event. Finally, SUVA of lateral subsurface flow was lower than SUVA of stream water at the seasonal scale, indicating a difference in mixing of water sources at the hillslope and catchment scale. Overall, our results show that SUVA and fluorescence are useful tracers for fingerprinting DOC sources.

  8. Photosynthetically active radiation (PAR) x ultraviolet radiation (UV) interact to initiate solar injury in apple

    USDA-ARS?s Scientific Manuscript database

    Sunburn or solar injury (SI) in apple is associated with high temperature, high visible light and ultraviolet radiation (UV). Fruit surface temperature (FST) thresholds for SI related disorders have been developed but there are no thresholds established for solar radiation. The objectives of the s...

  9. An action spectrum for UV-B radiation and the rat lens.

    PubMed

    Merriam, J C; Löfgren, S; Michael, R; Söderberg, P; Dillon, J; Zheng, L; Ayala, M

    2000-08-01

    To determine an action spectrum for UV-B radiation and the rat lens and to show the effect of the atmosphere and the cornea on the action spectrum. One eye of young female rats was exposed to 5-nm bandwidths of UV-B radiation (290, 295, 300, 305, 310, and 315 nm). Light scattering of exposed and nonexposed lenses was measured 1 week after irradiation. A quadratic polynomial was fit to the dose-response curve for each wave band. The dose at each wave band that produced a level of light scattering greater than 95% of the nonexposed lenses was defined as the maximum acceptable dose (MAD). Transmittance of the rat cornea was measured with a fiberoptic spectrophotometer. The times to be exposed to the MAD in Stockholm (59.3 degrees N) and La Palma (28 degrees N) were compared. Significant light scattering was detected after UV-B at 295, 300, 305, 310, and 315 nm. The lens was most sensitive to UV-B at 300 nm. Correcting for corneal transmittance showed that the rat lens is at least as sensitive to UV radiation at 295 nm as at 300 nm. The times to be exposed to the MAD at each wave band were greater in Stockholm than in La Palma, and in both locations the theoretical time to be exposed to the MAD was least at 305 nm. After correcting for corneal transmittance, the biological sensitivity of the rat lens to UV-B is at least as great at 295 nm as at 300 nm. After correcting for transmittance by the atmosphere, UV-B at 305 nm is the most likely wave band to injure the rat lens in both Stockholm and La Palma.

  10. Combination of UV absorbance and electron donating capacity to assess degradation of micropollutants and formation of bromate during ozonation of wastewater effluents.

    PubMed

    Chon, Kangmin; Salhi, Elisabeth; von Gunten, Urs

    2015-09-15

    In this study, the changes in UV absorbance at 254 nm (UVA254) and electron donating capacity (EDC) were investigated as surrogate indicators for assessing removal of micropollutants and bromate formation during ozonation of wastewater effluents. To measure the EDC, a novel method based on size exclusion chromatography followed by a post-column reaction was developed and calibrated against an existing electrochemical method. Low specific ozone doses led to a more efficient abatement of EDC than of UVA254. This was attributed to the abatement of phenolic moieties in the dissolved organic matter (DOM), which lose their EDC upon oxidation, but are partially transformed into quinones, which still absorb in the measured UV range. For higher specific ozone doses, the relative EDC abatement was lower than the relative UVA abatement, which can be explained by the oxidation of UV absorbing moieties (e.g. non-activated aromatic compounds), which contribute less to EDC. The abatement of the selected micropollutants (i.e., 17α-ethinylestradiol (EE2), carbamazepine (CBZ), atenolol (ATE), bezafibrate (BZF), ibuprofen (IBU), and p-chlorobenzoic acid (pCBA)) varied significantly depending on their reactivity with ozone in the examined specific ozone dose range of 0-1.45 mgO3/mgDOC. The decrease of EE2 and CBZ with high ozone reactivity was linearly proportional to the reduction of the relative residuals of UVA254 and EDC. The abatement of ATE, BZF, IBU, and pCBA with intermediate to low ozone reactivities was not significant in a first phase (UVA254/UVA254,0 = 1.00-0.70; EDC/EDC0 = 1.00-0.56) while their abatement was more efficient than the degradation of the relative residual UVA254 and much more noticeable than the degradation of the relative residual EDC in a second phase (UVA254/UVA254,0 = 0.70-0.25; EDC/EDC0 = 0.56-0.25) because the partially destroyed UV absorbing and electron donating DOM moieties become recalcitrant to ozone attack. Bromate formation was

  11. Quantifying the impact of smoke aerosol on the UV radiation

    NASA Astrophysics Data System (ADS)

    Sokolik, I. N.; Tatarskii, V.; Hall, S. R.; Petropavlovskikh, I. V.

    2017-12-01

    We present an analysis of the impact of smoke on the UV radiation. The analysis is performed for a case study by combining the modeling and measurements. The case study is focusing in wildfires occurred in California in ????. The fires have been affecting the environment in the region, posing a serious threat to the human well - being.The modeling is performed using a fully couple WRF- Chem- SMOKE model. The model uses the FRP MODIS satellite data to generate the smoke emission for an actual event. The smoke aerosol is treated in a size and composition resolved manner. The optical properties are computed online and provided to the TUV model that is incorporated in the WRF - Chem-SMOKE model. The analysis of the impact of smoke on the UV radiation is performed. We assess the impact of smoke on the TOA radiative forcing. Our results show a significant impact of smoke on the radiative regime of the atmosphere.

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

    NASA Astrophysics Data System (ADS)

    Feister, U.; Junk, J.; Woldt, M.; Bais, A.; Helbig, A.; Janouch, M.; Josefsson, W.; Kazantzidis, A.; Lindfors, A.; den Outer, P. N.; Slaper, H.

    2008-06-01

    Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Special emphasis will be given to the discussion of small-scale characteristics of input data to the ANN model. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980/1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

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

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

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

  14. UV-C radiation increases sterol production in the microalga Pavlova lutheri.

    PubMed

    Ahmed, Faruq; Schenk, Peer M

    2017-07-01

    Plant sterols have become well-known to promote cardiovascular health through the reduction of low density lipoprotein cholesterol in the blood. Plant sterols also have anti-inflammatory, anti-cancer, anti-oxidative and anti-atherogenicity activities. Microalgae have the potential to become a useful alternative source of plant sterols with several species reported to have higher concentrations than current commercial ones. In order to increase phytosterol production and optimise culture conditions, the high sterol producer Pavlova lutheri was treated in different dosages (50-250 mJ m -2 ) of UV-C radiation and several concentrations (1-500 μmol/L) of hydrogen peroxide (H 2 O 2 ) and the sterol contents were quantified for two days after the treatments. The contents of malondialdehyde (MDA) superoxide dismutase (SOD) as indications of cell membrane damage by lipid peroxidation and repair of oxidative stress, respectively, were measured. Higher activities of SOD and MDA were observed in the treated biomass when compared to the controls. Total sterols increased in P. lutheri due to UV-C radiation (at 100 mJ m -2 ) but not in response to H 2 O 2 treatment. Among the nineteen sterol compounds identified in P. lutheri, poriferasterol, epicampesterol, methylergostenol, fungisterol, dihydrochondrillasterol, and chondrillasterol increased due to UV-C radiation. Therefore, UV-C radiation can be a useful tool to boost industrial phytosterol production from P. lutheri. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    1992-08-01

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

  16. Influence of UV radiation on chlorophyll, and antioxidant enzymes of wetland plants in different types of constructed wetland.

    PubMed

    Xu, Defu; Wu, Yinjuan; Li, Yingxue; Howard, Alan; Jiang, Xiaodong; Guan, Yidong; Gao, Yongxia

    2014-09-01

    A surface- and vertical subsurface-flow-constructed wetland were designed to study the response of chlorophyll and antioxidant enzymes to elevated UV radiation in three types of wetland plants (Canna indica, Phragmites austrail, and Typha augustifolia). Results showed that (1) chlorophyll content of C. indica, P. austrail, and T. augustifolia in the constructed wetland was significantly lower where UV radiation was increased by 10 and 20 % above ambient solar level than in treatment with ambient solar UV radiation (p < 0.05). (2) The malondialdehyde (MDA) content, guaiacol peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities of wetland plants increased with elevated UV radiation intensity. (3) The increased rate of MDA, SOD, POD, and CAT activities of C. indica, P. australis, and T. angustifolia by elevated UV radiation of 10 % was higher in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. The sensitivity of MDA, SOD, POD, and CAT activities of C. indica, P. austrail, and T. augustifolia to the elevated UV radiation was lower in surface-flow-constructed wetland than in the vertical subsurface-flow-constructed wetland, which was related to a reduction in UV radiation intensity through the dissolved organic carbon and suspended matter in the water. C. indica had the highest SOD and POD activities, which implied it is more sensitive to enhanced UV radiation. Therefore, different wetland plants had different antioxidant enzymes by elevated UV radiation, which were more sensitive in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland.

  17. Preharvest UV-C radiation influences physiological, biochemical, and transcriptional changes in strawberry cv. Camarosa.

    PubMed

    de Oliveira, Isadora Rubin; Crizel, Giseli Rodrigues; Severo, Joseana; Renard, Catherine M G C; Chaves, Fabio Clasen; Rombaldi, Cesar Valmor

    2016-11-01

    Ultraviolet C (UV-C) radiation is known for preventing fungal decay and enhancing phytochemical content in fruit when applied postharvest. However, limited knowledge is available regarding fruit responses to preharvest application of UV-C radiation. Thus, the effects of UV-C radiation on photosynthetic efficiency, dry matter accumulation and partitioning, fruit yield and decay, phytochemical content, and relative transcript accumulation of genes associated with these metabolic pathways were monitored in strawberry (Fragaria x ananassa Duch.) cv. Camarosa. A reduction in photosynthetic efficiency was followed by a decrease in light harvesting complex LhcIIb-1 mRNA accumulation as well as a decrease in yield per plant. Phenylalanine ammonia lyase activity, phenolic, anthocyanin, and L-ascorbic acid contents were higher in UV-C treated fruit. In addition, preharvest UV-C treatment reduced microorganism incidence in the greenhouse and on the fruit surface, increased the accumulation of β-1,3-Gluc and PR-1 mRNA, and prevented fruit decay. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

    Mitchell, B. Greg; Lubin, Dan

    2005-01-01

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

  19. The total ozone and UV solar radiation over Stara Zagora, Bulgaria

    NASA Astrophysics Data System (ADS)

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

    Direct ground-based UV measurements and the total ozone content (TOC) over Stara Zagora, Bulgaria are presented. The observations are conducted by a scanning spectrophotometer, which measures the direct solar radiation in the range 290 - 360 nm with 1 nm resolution. For the time period 1998 -- 2003 the TOC data show seasonal variations, typical for the middle latitudes -- maximum in the spring and minimum in the autumn. The comparison of these TOC ground-based data to TOC satellite-borne data from the Global Ozone Monitoring Experiment (GOME) shows a seasonal dependence of the differences between the ground-based and satellite data. The relation between the UV radiation and TOC is investigated. Clear negative relationship is recognized between the total ozone and the irradiance of the wavelength 305 nm. The opposition of the two variables is significant ( r = - 0,62 ± 0,18) at 98 % confidence level. Yet, for 325 nm it is almost independent with the total ozone. The dependence of the UV-B radiation on the solar zenith angle at given TOC is also analyzed. A decrease of all wavelengths intensities with increase of the solar zenith angle is obtained but with different rate for each of them. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained as the integral in the wavelength interval 290-330 nm of the measured UV solar spectrum, weighted with an action spectrum, typical for each effect. The estimation of the radiation amplification factor RAF shows that the ozone reduction by 1% increases the erythemal dose by 2,3 %.The eye-damaging doses are more influenced by the TOC changes and in this case RAF=-2,7%. The amount of these biological doses is in a direct ratio with the solar altitude over the horizon. This dependence is more markedly expressed at lower total ozone content in the atmosphere.

  20. Assessment of UV biological spectral weighting functions for phenolic metabolites and growth responses in silver birch seedlings.

    PubMed

    Kotilainen, Titta; Venäläinen, Tuulia; Tegelberg, Riitta; Lindfors, Anders; Julkunen-Tiitto, Riitta; Sutinen, Sirkka; O'Hara, Robert B; Aphalo, Pedro J

    2009-01-01

    In research concerning stratospheric ozone depletion, action spectra are used as biological spectral weighting functions (BSWFs) for describing the effects of UV radiation on plant responses. Our aim was to evaluate the appropriateness of six frequently used BSWFs that differ in effectiveness with increasing wavelength. The evaluation of action spectra was based on calculating the effective UV radiation doses according to 1-2) two formulations of the generalized plant action spectrum, 3) a spectrum for ultraviolet induced erythema in human skin, 4) a spectrum for the accumulation of a flavonol in Mesembryanthemum crystallinum, 5) a spectrum for DNA damage in alfalfa seedlings and 6) the plant growth action spectrum. We monitored effects of UV radiation on the concentration of individual UV absorbing metabolites and chlorophyll concentrations in leaves and growth responses of silver birch (Betula pendula) seedlings. Experiments were conducted outdoors using plastic films attenuating different parts of the UV spectrum. Chlorophyll concentrations and growth were not affected by the UV treatments. The response to UV radiation varied between and within groups of phenolics. In general, the observed responses of phenolic groups and individual flavonoids were best predicted by action spectra extending into the UV-A region with moderate effectiveness.

  1. Effects of terrestrial UV radiation on selected outdoor materials: an interdisciplinary approach

    NASA Astrophysics Data System (ADS)

    Heikkilä, A.; Kazadzis, S.; Tolonen-Kivimäki, O.; Meinander, O.; Lindfors, A.; Lakkala, K.; Koskela, T.; Kaurola, J.; Sormanen, A.; Kärhä, P.; Naula-Iltanen, A.; Syrjälä, S.; Kaunismaa, M.; Juhola, J.; Ture, T.; Feister, U.; Kouremeti, N.; Bais, A.; Vilaplana, J. M.; Rodriguez, J. J.; Guirado, C.; Cuevas, E.; Koskinen, J.

    2009-08-01

    Modern polymeric materials possess an ever increasing potential in a large variety of outdoor objects and structures offering an alternative for many traditional materials. In outdoor applications, however, polymers are subject to a phenomenon called weathering. This is primarily observed as unwanted property changes: yellowing or fading, chalking, blistering, and even severe erosion of the material surface. One of the major weathering factors is UV radiation. In spring 2005, the Finnish Meteorological Institute with its research and industrial partners launched a five-year material research project named UVEMA (UV radiation Effects on MAterials). Within the framework of the project, a weathering network of seven European sites was established. The network extends from the Canary Islands of Spain (latitude 28.5°N) to the Lapland of Finland (latitude 67.4°N), covering a wide range of UV radiation conditions. Since autumn 2005, the sites of the network have been maintaining weathering platforms of specimens of different kinds of polymeric materials. At the same time, the sites have been maintaining their long-term monitoring programmes for spectrally resolved UV radiation. Within UVEMA, these data are used for explaining the differences between the degradation rates of the materials at each site and for correlating the UV conditions in accelerated ageing tests to those under the Sun. We will present the objectives of the UVEMA project aiming at deeper understanding of the ageing of polymers and more reliable assessments for their service life time. Methodologies adopted within the project and the first results of the project will be summarized.

  2. Scutellaria radix Extract as a Natural UV Protectant for Human Skin.

    PubMed

    Seok, Jin Kyung; Kwak, Jun Yup; Choi, Go Woon; An, Sang Mi; Kwak, Jae-Hoon; Seo, Hyeong-Ho; Suh, Hwa-Jin; Boo, Yong Chool

    2016-03-01

    Ultraviolet (UV) radiation induces oxidative injury and inflammation in human skin. Scutellaria radix (SR, the root of Scutellaria baicalensis Georgi) contains flavonoids with high UV absorptivity and antioxidant properties. The purpose of this study was to examine the potential use of SR extract as an additive in cosmetic products for UV protection. SR extract and its butanol (BuOH) fraction strongly absorbed UV radiation and displayed free radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radials and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals. They also attenuated the UV-induced death of HaCaT cells. Sunscreen creams, with or without supplementation of SR extract BuOH fraction, were tested in vivo in human trials to evaluate potential skin irritation and determine the sun protection factor (SPF). Both sunscreen creams induced no skin irritation. A sunscreen cream containing 24% ZnO showed an SPF value of 17.8, and it increased to 22.7 when supplemented with 5% SR extract BuOH fraction. This study suggests that SR-derived materials are useful as safe cosmetic additives that provide UV protection. Copyright © 2015 John Wiley & Sons, Ltd.

  3. Generating a heated fluid using an electromagnetic radiation-absorbing complex

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    A vessel including a concentrator configured to concentrate electromagnetic (EM) radiation received from an EM radiation source and a complex configured to absorb EM radiation to generate heat. The vessel is configured to receive a cool fluid from the cool fluid source, concentrate the EM radiation using the concentrator, apply the EM radiation to the complex, and transform, using the heat generated by the complex, the cool fluid to the heated fluid. The complex is at least one of consisting of copper nanoparticles, copper oxide nanoparticles, nanoshells, nanorods, carbon moieties, encapsulated nanoshells, encapsulated nanoparticles, and branched nanostructures. Further, the EMmore » radiation is at least one of EM radiation in an ultraviolet region of an electromagnetic spectrum, in a visible region of the electromagnetic spectrum, and in an infrared region of the electromagnetic spectrum.« less

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

    PubMed

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

    2017-02-01

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

  5. A comparative approach of methylparaben photocatalytic degradation assisted by UV-C, UV-A and Vis radiations.

    PubMed

    Doná, Giovanna; Dagostin, João Luiz Andreoti; Takashina, Thiago Atsushi; de Castilhos, Fernanda; Igarashi-Mafra, Luciana

    2018-05-01

    Due to the widespread use of methylparaben (MEP) and its high chemical stability, it can be found in wastewater treatment plants and can act as an endocrine disrupting compound. In this study, the photocatalytic degradation and mineralization of MEP solutions were evaluated under UV-A, UV-C and Vis radiations in the presence of the photocatalyst TiO 2 . In this sense, the effects of the catalyst load, pH and MEP initial concentration were studied. Remarkably higher reaction rates and total photodegradation were achieved in systems assisted by UV-C radiation. The complete degradation was achieved after 60 min of reaction using the MEP concentration of 30 mg L -1 at pH 9 and 500 mg L -1 TiO 2 . The experimental data apparently followed a Langmuir-Hinshelwood kinetic model, which could predict 88-98% of the reaction behavior. For the best photodegradation condition, the model predicted an apparent reaction rate constant (k app ) equal to 0.0505 min -1 and an initial reaction rate of 1.5641 mg (L min) -1 . Mineralization analyses showed high removal for MEP and derived compounds from the initial solution when using UV-C after 90 min of reaction. The lower toxicity was also confirmed by in vivo tests using MEP solutions previously treated by photocatalysis.

  6. INTERACTIONS OF SOLAR UV RADIATION AND DISSOLVED ORGANIC MATTER IN AQUATIC ENVIRONMENTS

    EPA Science Inventory

    Changes in the ozone layer over the past two decades have resulted in increases in solar ultraviolet (UV) radiation that reaches the surface of aquatic environments. Recent studies have demonstrated that these UV increases cause changes in photochemical reactions that affect the...

  7. Developmental reprogramming by UV-B radiation in plants.

    PubMed

    Dotto, Marcela; Casati, Paula

    2017-11-01

    Plants are extremely plastic organisms with the ability to adapt and respond to the changing environmental conditions surrounding them. Sunlight is one of the main resources for plants, both as a primary energy source for photosynthesis and as a stimulus that regulates different aspects of their growth and development. UV-B comprises wavelengths that correspond to a high energy region of the solar spectrum capable of reaching the biosphere, influencing plant growth. It is currently believed that plants are able to acclimate when growing under the influence of this radiation and perceive it as a signal, without stress signs. Nonetheless, many UV-B induced changes are elicited after DNA damage occurs as a consequence of exposure. In this review we focus on the influence of UV-B on leaf, flower and root development and emphasize the limited understanding of the molecular mechanisms for most of this developmental processes affected by UV-B documented over the years of research in this area. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. UV-B radiation-induced oxidative stress and p38 signaling pathway involvement in the benthic copepod Tigriopus japonicus.

    PubMed

    Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Kyun-Woo; Kim, Min-Jung; Shin, Kyung-Hoon; Lee, Su-Jae; Lee, Young-Mi; Lee, Jae-Seong

    2015-01-01

    Ultraviolet B (UV-B) radiation presents an environmental hazard to aquatic organisms. To understand the molecular responses of the intertidal copepod Tigriopus japonicus to UV-B radiation, we measured the acute toxicity response to 96 h of UV-B radiation, and we also assessed the intracellular reactive oxygen species (ROS) levels, glutathione (GSH) content, and antioxidant enzyme (GST, GR, GPx, and SOD) activities after 24 h of exposure to UV-B with LD50 and half LD50 values. Also, expression patterns of p53 and hsp gene families with phosphorylation of p38 MAPK were investigated in UV-B-exposed copepods. We found that the ROS level, GSH content, and antioxidant enzyme activity levels were increased with the transcriptional upregulation of antioxidant-related genes, indicating that UV-B induces oxidative stress by generating ROS and stimulating antioxidant enzymatic activity as a defense mechanism. Additionally, we found that p53 expression was significantly increased after UV-B irradiation due to increases in the phosphorylation of the stress-responsive p38 MAPK, indicating that UV-B may be responsible for inducing DNA damage in T. japonicus. Of the hsp family genes, transcriptional levels of hsp20, hsp20.7, hsp70, and hsp90 were elevated in response to a low dose of UV-B radiation (9 kJ m(-2)), suggesting that these hsp genes may be involved in cellular protection against UV-B radiation. In this paper, we performed a pathway-oriented mechanistic analysis in response to UV-B radiation, and this analysis provides a better understanding of the effects of UV-B in the intertidal benthic copepod T. japonicus. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Influences of the clearness index on UV solar radiation for two locations in the Tibetan Plateau-Lhasa and Haibei

    NASA Astrophysics Data System (ADS)

    Hu, Bo; Wang, Yuesi; Liu, Guangren

    2008-09-01

    Ultraviolet (UV) solar radiation has a significant influence on human health, the environment and climate. A series of measurements, including UV radiation (290-400 nm) and global solar radiation ( R s), were continuously recorded from August 2004 at the Lhasa and Haibei sites on the Tibetan Plateau. Both observation sites’ altitudes are above 3000 m and have similar meteorological conditions. The data from 2005-2006 was used to identify the varying characteristics of UV radiation. It’s relation to the clearness index K s, the relative optical mass m r, and R s were established. The annual mean values of total daily UV radiation are 0.92 and 0.67 MJ m-2 at Lhasa and Haibei, respectively. The UV radiation in Lhasa represented 4.6% of the global solar radiation while in Haibei this percentage was 4.2%. In the case of clear days ( K s > 0.8), these percentages ranged between 4.0% and 4.5% in Lhasa and between 5.1% and 5.5% in Haibei. In the case of cloudy days ( K s < 0.4), these percentages ranged from 4.4% to 6.8% in Lhasa and from 5.1% to 5.5% in Haibei. The maximum values of UV radiation for each relative optical mass diminished exponentially with m r. Thus, for Lhasa and Haibei, UV=46.25 m {4/-1.29}, and UV=51.76 m {r/-1.42}, respectively. The results of this study can be used to obtain more UV radiation data for the study of UV climate characteristics, the effects of UV on ecological processes and the feedback of the thinning of the stratospheric ozone, from more routine measurements R s data.

  10. The effect of UV radiation from oxygen and argon plasma on the adhesion of organosilicon coatings on polypropylene

    NASA Astrophysics Data System (ADS)

    Jaritz, M.; Behm, H.; Hopmann, Ch; Kirchheim, D.; Mitschker, F.; Awakowicz, P.; Dahlmann, R.

    2017-01-01

    The influence of ultraviolet (UV) radiation from oxygen and argon pretreatment plasmas on a plastic substrate has not been fully understood yet. In particular, its influence on the adhesion properties has not been sufficiently researched so far. This paper addresses this issue by comparing the bond strength of a plasmapolymerized silicon organic coating (SiO x C y H z ) on polypropylene (PP) after oxygen and argon plasma pretreatment and pretreatment by UV radiation emitted by the same plasmas. The UV radiation is isolated from the other species from the plasma by means of a magnesium fluoride (MgF2) optical filter. It could be shown that UV radiation originating from an oxygen plasma has a significant impact on both substrate surface chemistry and coating adhesion. The same maximum bond strength enhancement can be reached by pretreating the polypropylene surface either with pulsed oxygen plasma, or with only the UV radiation from this oxygen plasma. Also, similar surface chemistry and topography modifications are induced. For argon plasma no significant influence of its UV radiation on the substrate could be observed in this study.

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

    NASA Astrophysics Data System (ADS)

    Li, Jie; Liu, Ying; Wang, Ning; Jin, Ling

    2014-12-01

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

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

    PubMed Central

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

    2013-01-01

    Due to the role leaf phenolics in defending against ultraviolet B (UVB) under previously controlled conditions, we hypothesize that ultraviolet radiation (UVR) could be a primary factor driving the variation in leaf phenolics in plants over a large geographic scale. We measured leaf total phenolics, ultraviolet-absorbing compounds (UVAC), and corresponding leaf N, P, and specific leaf area (SLA) in 151 common species. These species were from 84 sites across the Tibetan Plateau and Inner Mongolian grasslands of China with contrasting UVR (354 vs. 161 mW/cm2 on average). Overall, leaf phenolics and UVAC were all significantly higher on the Tibetan Plateau than in the Inner Mongolian grasslands, independent of phylogenetic relationships between species. Regression analyses showed that the variation in leaf phenolics was strongly affected by climatic factors, particularly UVR, and soil attributes across all sites. Structural equation modeling (SEM) identified the primary role of UVR in determining leaf phenolic concentrations, after accounting for colinearities with altitude, climatic, and edaphic factors. In addition, phenolics correlated positively with UVAC and SLA, and negatively with leaf N and N: P. These relationships were steeper in the lower-elevation Inner Mongolian than on the Tibetan Plateau grasslands. Our data support that the variation in leaf phenolics is controlled mainly by UV radiation, implying high leaf phenolics facilitates the adaptation of plants to strong irradiation via its UV-screening and/or antioxidation functions, particularly on the Tibetan Plateau. Importantly, our results also suggest that leaf phenolics may influence on vegetation attributes and indirectly affect ecosystem processes by covarying with leaf functional traits. PMID:24363898

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

    PubMed

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

    2011-11-01

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

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

    DOE PAGES

    Erickson III, David J.; Sulzberger, Barbara; Zepp, Richard G.; ...

    2014-11-07

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UV-induced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced mineralisation of photoreactive dissolved organic matter (DOM) in aquatic ecosystems due to changes in continental runoff and ice melting; (iii) reduced efficiency of the biological pump due to UV-induced bleaching of coloured dissolved organic matter (CDOM) in stratified aquatic ecosystems, where CDOM protects phytoplankton from the damaging solarmore » UV-B radiation. Mineralisation of organic matter results in the production and release of CO 2, whereas the biological pump is the main biological process for CO 2 removal by aquatic ecosystems. This research also assesses the interactive effects of solar UV radiation and climate change on the biogeochemical cycling of aerosols and trace gases other than CO 2, as well as of chemical and biological contaminants. Lastly,, interacting effects of solar UV radiation and climate change on biogeochemical cycles are particularly pronounced at terrestrial-aquatic interfaces.« less

  15. Space radiation absorbed dose distribution in a human phantom

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

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

    PubMed

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

    2018-02-01

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

  17. Hybrid AlGaN-SiC Avalanche Photodiode for Deep-UV Photon Detection

    NASA Technical Reports Server (NTRS)

    Aslam, Shahid; Herrero, Federico A.; Sigwarth, John; Goldsman, Neil; Akturk, Akin

    2010-01-01

    The proposed device is capable of counting ultraviolet (UV) photons, is compatible for inclusion into space instruments, and has applications as deep- UV detectors for calibration systems, curing systems, and crack detection. The device is based on a Separate Absorption and Charge Multiplication (SACM) structure. It is based on aluminum gallium nitride (AlGaN) absorber on a silicon carbide APD (avalanche photodiode). The AlGaN layer absorbs incident UV photons and injects photogenerated carriers into an underlying SiC APD that is operated in Geiger mode and provides current multiplication via avalanche breakdown. The solid-state detector is capable of sensing 100-to-365-nanometer wavelength radiation at a flux level as low as 6 photons/pixel/s. Advantages include, visible-light blindness, operation in harsh environments (e.g., high temperatures), deep-UV detection response, high gain, and Geiger mode operation at low voltage. Furthermore, the device can also be designed in array formats, e.g., linear arrays or 2D arrays (micropixels inside a superpixel).

  18. Characterization of an Escherichia coli mutant (radB101) sensitive to. gamma. and uv radiation, and methyl methanesulfonate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sargentini, N.J.; Smith, K.C.

    1983-03-01

    After N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis of Escherichia coli K-12 (xthA14), an X-ray-sensitive mutant was isolated. This sensitivity is due to a mutation, radB101, which is located at 56.5 min on the E.coli K-12 linkage map. The radB101 mutation sensitized wild-type cells to ..gamma.. and uv radiation, and to methyl methanesulfonate. When known DNA repair-deficient mutants were ranked for their ..gamma..-radiation sensitivity relative to their uv-radiation sensitivity, their order was (starting with the most selectively ..gamma..-radiation-sensitive strain): recB21, radB101, wild type, polA1, recF143, lexA101, recA56, uvrD3, and uvrA6. The radB mutant was normal for ..gamma..- and uv-radiation mutagenesis, it showed only a slightmore » enhancement of ..gamma..- and uv-radiation-induced DNA degradation, and it was approx. 60% deficient in recombination ability. The radB gene is suggested to play a role in the recA gene-dependent (Type III) repair of DNA single-strand breaks after ..gamma.. irradiation and in postreplication repair after uv irradiation for the following reasons: the radB strain was normal for the host-cell reactivation of ..gamma..- and uv-irradiated bacteriophage lambda; the radB mutation did not sensitize a recA strain, but did sensitize a polA strain to ..gamma.. and uv radiation; the radB mutation sensitized a uvrB strain to uv radiation.« less

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

    PubMed

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

    2015-05-01

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

  20. Physical properties of organic particulate UV-absorbers used in sunscreens. I. Determination of particle size with fiber-optic quasi-elastic light scattering (FOQELS), disc centrifugation, and laser diffractometry.

    PubMed

    Herzog, Bernd; Katzenstein, Armin; Quass, Katja; Stehlin, Albert; Luther, Helmut

    2004-03-01

    In this study microparticles consisting of a benzotriazole derivative, which are used as absorbers for UV radiation in cosmetic sunscreens, were investigated. The particles were micronized in presence of a dispersing agent by means of a ball milling process. According to the energy input different particle sizes were produced in the range of 0.16 to 4 microm. The particle sizes obtained after different stages of the micronization process were measured using fiber-optic quasi-elastic light scattering (FOQELS), disc centrifugation, and laser diffractometry. All methods showed satisfactory agreement over the whole range of sizes. With the FOQELS technique the particle size distribution could be resolved to sizes well below 0.1 microm.

  1. The budget of biologically active ultraviolet radiation in the earth-atmosphere system

    NASA Technical Reports Server (NTRS)

    Frederick, John E.; Lubin, Dan

    1988-01-01

    This study applies the concept of a budget to describe the interaction of solar ultraviolet (UV) radiation with the earth-atmosphere system. The wavelength ranges of interest are the biologically relevant UV-B between 280 and 320 nm and the UV-A from 32000 to 400 nm. The Nimbus 7 solar backscattered ultraviolet (SBUV) instrument provides measurements of total column ozone and information concerning cloud cover which, in combination with a simple model of radiation transfer, define the fractions of incident solar irradiance absorbed in the atmosphere, reflected to space, and absorbed at the ground. Results for the month of July quantify the contribution of fractional cloud cover and cloud optical thickness to the radiation budget's three components. Scattering within a thick cloud layer makes the downward radiation field at the cloud base more isotropic than is the case for clear skies. For small solar zenith angles, typical of summer midday conditions, the effective pathlength of this diffuse irradiance through tropospheric ozone is greater than that under clear-sky conditions. The result is an enhanced absorption of UV-B radiation in the troposphere during cloud-covered conditions. Major changes in global cloud cover or cloud optical thicknesses could alter the ultraviolet radiation received by the biosphere by an amount comparable to that predicted for long-term trends in ozone.

  2. Beneficial effects of solar UV-B radiation on soybean yield mediated by reduced insect herbivory under field conditions.

    PubMed

    Mazza, Carlos A; Giménez, Patricia I; Kantolic, Adriana G; Ballaré, Carlos L

    2013-03-01

    Ultraviolet-B radiation (UV-B: 280-315 nm) has damaging effects on cellular components and macromolecules. In plants, natural levels of UV-B can reduce leaf area expansion and growth, which can lead to reduced productivity and yield. UV-B can also have important effects on herbivorous insects. Owing to the successful implementation of the Montreal Protocol, current models predict that clear-sky levels of UV-B radiation will decline during this century in response to ozone recovery. However, because of climate change and changes in land use practices, future trends in UV doses are difficult to predict. In the experiments reported here, we used an exclusion approach to study the effects of solar UV-B radiation on soybean crops, which are extensively grown in many areas of the world that may be affected by future variations in UV-B radiation. In a first experiment, performed under normal management practices (which included chemical pest control), we found that natural levels of UV-B radiation reduced soybean yield. In a second experiment, where no pesticides were applied, we found that solar UV-B significantly reduced insect herbivory and, surprisingly, caused a concomitant increase in crop yield. Our data support the idea that UV-B effects on agroecosystems are the result of complex interactions involving multiple trophic levels. A better understanding of the mechanisms that mediate the anti-herbivore effect of UV-B radiation may be used to design crop varieties with improved adaptation to the cropping systems that are likely to prevail in the coming decades in response to agricultural intensification. Copyright © Physiologia Plantarum 2012.

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

    EPA Science Inventory

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

  4. Impulse powerful UV-radiation source pumped by the sublight ionization waves for the bacteriological disinfection of water

    NASA Astrophysics Data System (ADS)

    Filiouguine, Igor V.; Kostiouchenko, S. V.; Koudryavtsev, N. N.; Vasilyak, Leonid M.; Yakimenko, A. V.

    1993-11-01

    The bacteriological disinfective action of UV-radiation is well known. The pioneer work on UV-radiation used for bacteriological disinfection of waste water was made in 1910. Because of the high cost and low living time of the UV-radiation sources, the alternative technique for waste water purification by chlorine introducing was spread out. During the second stage of the UV purification development, beginning in approximately 1970, the interest for bacteriological cleaning of water, increased again. Two reasons were responsible for this event: first, the significant improvement of technology and design of UV-bacteriological purificators, and second, recognition of the serious danger of chlorine compounds introduced into water under purification because of the toxicity of these compounds. Further investigations gave excellent results in the creation and industrial applications of UV- bacteriological purificators. Now we can see a rapid development of industrial technology in UV-purification of drinking and waste waters.

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

    PubMed

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

    2010-11-01

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

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    1982-02-01

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

  7. Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures.

    PubMed

    Kloeze, C; Klompenhouwer, E G; Brands, P J M; van Sambeek, M R H M; Cuypers, P W M; Teijink, J A W

    2014-03-01

    Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  8. Effects of morphology on the radiative properties of internally mixed light absorbing carbon aerosols with different aging status.

    PubMed

    Cheng, Tianhai; Wu, Yu; Chen, Hao

    2014-06-30

    Light absorbing carbon aerosols play a substantial role in climate change through radiative forcing, which is the dominant absorber of solar radiation. Radiative properties of light absorbing carbon aerosols are strongly dependent on the morphological factors and the mixing mechanism of black carbon with other aerosol components. This study focuses on the morphological effects on the optical properties of internally mixed light absorbing carbon aerosols using the numerically exact superposition T-matrix method. Three types aerosols with different aging status such as freshly emitted BC particles, thinly coated light absorbing carbon aerosols, heavily coated light absorbing carbon aerosols are studied. Our study showed that morphological factors change with the aging of internally mixed light absorbing carbon aerosols to result in a dramatic change in their optical properties. The absorption properties of light absorbing carbon aerosols can be enhanced approximately a factor of 2 at 0.67 um, and these enhancements depend on the morphological factors. A larger shell/core diameter ratio of volume-equivalent shell-core spheres (S/C), which indicates the degree of coating, leads to stronger absorption. The enhancement of absorption properties accompanies a greater enhancement of scattering properties, which is reflected in an increase in single scattering albedo (SSA). The enhancement of single scattering albedo due to the morphological effects can reach a factor of 3.75 at 0.67 μm. The asymmetry parameter has a similar yet smaller enhancement. Moreover, the corresponding optical properties of shell-and-core model determined by using Lorenz -Mie solutions are presented for comparison. We found that the optical properties of internally mixed light absorbing carbon aerosol can differ fundamentally from those calculated for the Mie theory shell-and-core model, particularly for thinly coated light absorbing carbon aerosols. Our studies indicate that the complex morphology

  9. ESTIMATION OF UV RADIATION DOSE IN NORTHERN MINNESOTA WETLANDS

    EPA Science Inventory

    The ultraviolet (UV) B wavelength range (280 nm to 320 nm) of solar radiation can be a significant biological stressor, and has been hypothesized to be partially responsible for amphibian declines and malformation. This hypothesis has been difficult to evaluate, in part, because ...

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

    PubMed

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

    2017-09-01

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

  11. Solar UV Radiation and the Origin of Life on Earth

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Hubeny, Ivan; Lanz, Thierry; Gaidos, Eric; Kasting, James; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    We have started a comprehensive, interdisciplinary study of the influence of solar ultraviolet radiation on the atmosphere of of the early Earth. We plan to model the chemistry of the Earth atmosphere during its evolution, using observed UV flux distributions of early solar analogs as boundary conditions in photochemical models of the Earth's atmosphere. The study has four distinct but interlinked parts: (1) Establishing the radiation of the early Sun; (2) Determining the photochemistry of the early Earth's atmosphere; (3) Estimating the rates of H2 loss from the atmosphere; and (4) Ascertaining how sensitive is the photochemistry to the metallicity of the Sun. We are currently using STIS and EUVE to obtain high-quality far-UV and extreme-UV observations of three early-solar analogs. We will perform a detailed non-LTE study of each stars, and construct theoretical model photosphere, and an empirical model chromospheres, which can be used to extrapolate the continuum to the Lyman continuum region. Given a realistic flux distribution of the early Sun, we will perform photochemical modeling of weakly reducing primitive atmospheres to determine the lifetime and photochemistry of CH4. In particular, we will make estimates of the amount of CH4 present in the prebiotic atmosphere, and estimate the atmospheric CH4 concentration during the Late Archean (2.5-3.0 b.y. ago) and determine whether it would have been sufficiently abundant to help offset reduced solar luminosity at that time. Having obtained a photochemical model, we will solve for the concentrations of greenhouse gasses and important pre-biotic molecules, and perform a detailed radiative transfer calculations to compute the UV flux reaching the surface.

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

    PubMed

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

    2007-01-01

    The hydroponic culture experiments of soybean bean seedlings were conducted to investigate the effect of lanthanum (La) on nitrogen metabolism under two different levels of elevated UV-B radiation (UV-B, 280-320 nm). The whole process of nitrogen metabolism involves uptake and transport of nitrate, nitrate assimilation, ammonium assimilation, amino acid biosynthesis, and protein synthesis. Compared with the control, UV-B radiation with the intensity of low level 0.15 W/m2 and high level 0.45 W/m2 significantly affected the whole nitrogen metabolism in soybean seedlings (p < 0.05). It restricted uptake and transport of NO3(-), inhibited activity of some key nitrogen-metabolism-related enzymes, such as: nitrate reductase (NR) to the nitrate reduction, glutamine systhetase (GS) and glutamine synthase (GOGAT) to the ammonia assimilation, while it increased the content of free amino acids and decreased that of soluble protein as well. The damage effect of high level of UV-B radiation on nitrogen metabolism was greater than that of low level. And UV-B radiation promoted the activity of the anti-adversity enzyme glutamate dehydrogenase (GDH), which reduced the toxicity of excess ammonia in plant. After pretreatment with the optimum concentration of La (20 mg/L), La could increase the activity of NR, GS, GOGAT, and GDH, and ammonia assimilation, but decrease nitrate and ammonia accumulation. In conclusion, La could relieve the damage effect of UV-B radiation on plant by regulating nitrogen metabolism process, and its alleviating effect under low level was better than that under the high one.

  13. Distinct physiological and metabolic reprogramming by highbush blueberry (Vaccinium corymbosum) cultivars revealed during long-term UV-B radiation.

    PubMed

    Luengo Escobar, Ana; Alberdi, Miren; Acevedo, Patricio; Machado, Mariana; Nunes-Nesi, Adriano; Inostroza-Blancheteau, Claudio; Reyes-Díaz, Marjorie

    2017-05-01

    Despite the Montreal protocol and the eventual recovery of the ozone layer over Antarctica, there are still concerns about increased levels of ultraviolet-B (UV-B) radiation in the Southern Hemisphere. UV-B induces physiological, biochemical and morphological stress responses in plants, which are species-specific and different even for closely related cultivars. In woody plant species, understanding of long-term mechanisms to cope with UV-B-induced stress is limited. Therefore, a greenhouse UV-B daily course simulation was performed for 21 days with two blueberry cultivars (Legacy and Bluegold) under UV-B BE irradiance doses of 0, 0.07 and 0.19 W m -2 . Morphological changes, photosynthetic performance, antioxidants, lipid peroxidation and metabolic features were evaluated. We found that both cultivars behaved differently under UV-B exposure, with Legacy being a UV-B-resistant cultivar. Interestingly, Legacy used a combined strategy: initially, in the first week of exposure its photoprotective compounds increased, coping with the intake of UV-B radiation (avoidance strategy), and then, increasing its antioxidant capacity. These strategies proved to be UV-B radiation dose dependent. The avoidance strategy is triggered early under high UV-B radiation in Legacy. Moreover, the rapid metabolic reprogramming capacity of this cultivar, in contrast to Bluegold, seems to be the most relevant contribution to its UV-B stress-coping strategy. © 2016 Scandinavian Plant Physiology Society.

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

    EPA Science Inventory

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

  15. Predicting trace organic compound breakthrough in granular activated carbon using fluorescence and UV absorbance as surrogates.

    PubMed

    Anumol, Tarun; Sgroi, Massimiliano; Park, Minkyu; Roccaro, Paolo; Snyder, Shane A

    2015-06-01

    This study investigated the applicability of bulk organic parameters like dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254), and total fluorescence (TF) to act as surrogates in predicting trace organic compound (TOrC) removal by granular activated carbon in water reuse applications. Using rapid small-scale column testing, empirical linear correlations for thirteen TOrCs were determined with DOC, UV254, and TF in four wastewater effluents. Linear correlations (R(2) > 0.7) were obtained for eight TOrCs in each water quality in the UV254 model, while ten TOrCs had R(2) > 0.7 in the TF model. Conversely, DOC was shown to be a poor surrogate for TOrC breakthrough prediction. When the data from all four water qualities was combined, good linear correlations were still obtained with TF having higher R(2) than UV254 especially for TOrCs with log Dow>1. Excellent linear relationship (R(2) > 0.9) between log Dow and the removal of TOrC at 0% surrogate removal (y-intercept) were obtained for the five neutral TOrCs tested in this study. Positively charged TOrCs had enhanced removals due to electrostatic interactions with negatively charged GAC that caused them to deviate from removals that would be expected with their log Dow. Application of the empirical linear correlation models to full-scale samples provided good results for six of seven TOrCs (except meprobamate) tested when comparing predicted TOrC removal by UV254 and TF with actual removals for GAC in all the five samples tested. Surrogate predictions using UV254 and TF provide valuable tools for rapid or on-line monitoring of GAC performance and can result in cost savings by extended GAC run times as compared to using DOC breakthrough to trigger regeneration or replacement. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Effects of UV-B radiation on photosynthesis activity of Wolffia arrhiza as probed by chlorophyll fluorescence transients

    NASA Astrophysics Data System (ADS)

    Wang, Gaohong; Hao, Zongjie; Anken, Ralf H.; Lu, Jinying; Liu, Yongding

    2010-04-01

    The higher plant Wolffia arrhiza is regarded to be well suited concerning the provision of photosynthetic products in the cycle of matter of a Controlled Ecological Life Support System (CELSS) to be established in the context of extraterrestrial, human-based colonization and long-term space flight. Since UV radiation is one major extraterrestrial environmental stress for growth of any plant, effects of UV-B radiation on W. arrhiza were assessed in the present study. We found that UV-B radiation significantly inhibited photosynthetic CO2 assimilation activity, and the contents of chlorophyll a, chlorophyll b (Chl a, Chl b) and carotenoids considerably decreased when plants were exposed to UV-B radiation for 12 h. High UV-B radiation also declined the quantum yield of primary photochemistry (φpo), the quantum yield for electron transport (φEo) and the efficiency per trapped excitation (Ψo) in W. arrhiza simultaneously, while the amount of active PSII reaction centers per excited cross section (RC/CS) and the total number of active reaction centers per absorption (RC/ABS) had comparative changes. These results indicate that the effects of UV-B radiation on photosynthesis of W. arrhiza is due to an inhibition of the electron transport and via inactivation of reaction centers, but the inhibition may take place at more than one site in the photosynthetic apparatus.

  17. Preparation and characterization of functional poly(vinylidene fluoride) (PVDF) membranes with ultraviolet-absorbing property

    NASA Astrophysics Data System (ADS)

    Dong, Li; Liu, Xiangdong; Xiong, Zhengrong; Sheng, Dekun; Lin, Changhong; Zhou, Yan; Yang, Yuming

    2018-06-01

    We first reported a strategy to prepare functional poly(vinylidene fluoride) (PVDF) membranes with excellent ultraviolet-absorbing property through chemically induced grafting. Herein, the polymerizable ultraviolet (UV) absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA) made by ourselves was grafted onto the PVDF chains that have been pretreated with tetraethylammonium hydroxide (TEAH) alkaline solution. Moreover, the effect of experiment conditions such as the alkali and monomer concentrations, alkali treatment time on the UV-absorbing property of the obtained PVDF-g-PBPMA membranes were studied in detail. The chemical structure of the modified membranes was confirmed by 1H NMR, FT-IR and XPS measurements. Meanwhile, the thermal and UV-absorbing properties were characterized by TGA, DSC and UV-Vis spectrophotometer, respectively. The results indicated that BPMA side chains were successfully introduced onto PVDF backbones. Most importantly, the obtained PVDF-g-PBPMA membranes exhibited excellent UV-absorbing property. The transmittance of UV light at 300 nm decreased to as low as 0.02% and the UV light below 388 nm could be completely absorbed by the PVDF-g-PBPMA membrane made under optimal condition.

  18. Artificial and Solar UV Radiation Induces Strand Breaks and Cyclobutane Pyrimidine Dimers in Bacillus subtilis Spore DNA

    PubMed Central

    Slieman, Tony A.; Nicholson, Wayne L.

    2000-01-01

    The loss of stratospheric ozone and the accompanying increase in solar UV flux have led to concerns regarding decreases in global microbial productivity. Central to understanding this process is determining the types and amounts of DNA damage in microbes caused by solar UV irradiation. While UV irradiation of dormant Bacillus subtilis endospores results mainly in formation of the “spore photoproduct” 5-thyminyl-5,6-dihydrothymine, genetic evidence indicates that an additional DNA photoproduct(s) may be formed in spores exposed to solar UV-B and UV-A radiation (Y. Xue and W. L. Nicholson, Appl. Environ. Microbiol. 62:2221–2227, 1996). We examined the occurrence of double-strand breaks, single-strand breaks, cyclobutane pyrimidine dimers, and apurinic-apyrimidinic sites in spore DNA under several UV irradiation conditions by using enzymatic probes and neutral or alkaline agarose gel electrophoresis. DNA from spores irradiated with artificial 254-nm UV-C radiation accumulated single-strand breaks, double-strand breaks, and cyclobutane pyrimidine dimers, while DNA from spores exposed to artificial UV-B radiation (wavelengths, 290 to 310 nm) accumulated only cyclobutane pyrimidine dimers. DNA from spores exposed to full-spectrum sunlight (UV-B and UV-A radiation) accumulated single-strand breaks, double-strand breaks, and cyclobutane pyrimidine dimers, whereas DNA from spores exposed to sunlight from which the UV-B component had been removed with a filter (“UV-A sunlight”) accumulated only single-strand breaks and double-strand breaks. Apurinic-apyrimidinic sites were not detected in spore DNA under any of the irradiation conditions used. Our data indicate that there is a complex spectrum of UV photoproducts in DNA of bacterial spores exposed to solar UV irradiation in the environment. PMID:10618224

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

    NASA Astrophysics Data System (ADS)

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

    1998-11-01

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

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

    PubMed

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

    2016-06-01

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

  1. Effects of Solar Ultraviolet Radiation on the Potential Efficiency of Photosystem II in Leaves of Tropical Plants1

    PubMed Central

    Krause, G. Heinrich; Schmude, Claudia; Garden, Hermann; Koroleva, Olga Y.; Winter, Klaus

    1999-01-01

    The effects of solar ultraviolet (UV)-B and UV-A radiation on the potential efficiency of photosystem II (PSII) in leaves of tropical plants were investigated in Panama (9°N). Shade-grown tree seedlings or detached sun leaves from the outer crown of mature trees were exposed for short periods (up to 75 min) to direct sunlight filtered through plastic or glass filters that absorbed either UV-B or UV-A+B radiation, or transmitted the complete solar spectrum. Persistent changes in potential PSII efficiency were monitored by means of the dark-adapted ratio of variable to maximum chlorophyll a fluorescence. In leaves of shade-grown tree seedlings, exposure to the complete solar spectrum resulted in a strong decrease in potential PSII efficiency, probably involving protein damage. A substantially smaller decline in the dark-adapted ratio of variable to maximum chlorophyll a fluorescence was observed when UV-B irradiation was excluded. The loss in PSII efficiency was further reduced by excluding both UV-B and UV-A light. The photoinactivation of PSII was reversible under shade conditions, but restoration of nearly full activity required at least 10 d. Repeated exposure to direct sunlight induced an increase in the pool size of xanthophyll cycle pigments and in the content of UV-absorbing vacuolar compounds. In sun leaves of mature trees, which contained high levels of UV-absorbing compounds, effects of UV-B on PSII efficiency were observed in several cases and varied with developmental age and acclimation state of the leaves. The results show that natural UV-B and UV-A radiation in the tropics may significantly contribute to photoinhibition of PSII during sun exposure in situ, particularly in shade leaves exposed to full sunlight. PMID:10594122

  2. Review of reconstruction of radiation incident air kerma by measurement of absorbed dose in tooth enamel with EPR.

    PubMed

    Wieser, A

    2012-03-01

    Electron paramagnetic resonance dosimetry with tooth enamel has been proved to be a reliable method to determine retrospectively exposures from photon fields with minimal detectable doses of 100 mGy or lower, which is lower than achievable with cytogenetic dose reconstruction methods. For risk assessment or validating dosimetry systems for specific radiation incidents, the relevant dose from the incident has to be calculated from the total absorbed dose in enamel by subtracting additional dose contributions from the radionuclide content in teeth, natural external background radiation and medical exposures. For calculating organ doses or evaluating dosimetry systems the absorbed dose in enamel from a radiation incident has to be converted to air kerma using dose conversion factors depending on the photon energy spectrum and geometry of the exposure scenario. This paper outlines the approach to assess individual dose contributions to absorbed dose in enamel and calculate individual air kerma of a radiation incident from the absorbed dose in tooth enamel.

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

    PubMed

    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.

  4. Differential sensitivity of spinach and amaranthus to enhanced UV-B at varying soil nutrient levels: association with gas exchange, UV-B-absorbing compounds and membrane damage.

    PubMed

    Singh, Suruchi; Agrawal, Madhoolika; Agrawal, S B

    2013-07-01

    The metabolic reasons associated with differential sensitivity of C3 and C4 plant species to enhanced UV-B under varying soil nutrient levels are not well understood. In the present study, spinach (Spinacia oleracea L. var All Green), a C3 and amaranthus (Amaranthus tricolor L. var Pusa Badi Chaulai), a C4 plant were subjected to enhanced UV-B (280-315 nm; 7.2 kJ m(-2) day(-1)) over ambient under varying soil nutrient levels. The nutrient amendments were recommended Nitrogen (N), Phosphorus (P), Potassium (K), 1.5× recommended NPK, 1.5× recommended N and 1.5× recommended K. Enhanced UV-B negatively affected both the species at all nutrient levels, but the reductions varied with nutrient concentration and combinations. Reductions in photosynthetic rate, stomatal conductance and chlorophyll content were significantly more in spinach compared with amaranthus. The reduction in photosynthetic rate was maximum at 1.5× recommended K and minimum in 1.5× NPK amended plants. The oxidative damage to membranes measured in terms of malondialdehyde content was significantly higher in spinach compared with amaranthus. Enhanced UV-B reduced SOD activity in both the plants except in amaranthus at 1.5× recommended K. POX activity increased under enhanced UV-B at all nutrient levels in amaranthus, but only at 1.5× K in spinach. Amaranthus had significantly higher UV-B-absorbing compounds than spinach even under UV-B stress. Lowest reductions in yield and total biomass under enhanced UV-B compared with ambient were observed in amaranthus grown at 1.5× recommended NPK. Enhanced UV-B did not significantly change the nitrogen use efficiency in amaranthus at all NPK levels, but reduced in spinach except at 1.5× K. These findings suggest that the differential sensitivity of the test species under enhanced UV-B at varying nutrient levels is due to varying antioxidative and UV-B screening capacity, and their ability to utilize nutrients. Amaranthus tolerated enhanced UV-B stress

  5. Simulation of multi-element multispectral UV radiation source for optical-electronic system of minerals luminescence analysis

    NASA Astrophysics Data System (ADS)

    Peretyagin, Vladimir S.; Korolev, Timofey K.; Chertov, Aleksandr N.

    2017-02-01

    The problems of dressability the solid minerals are attracted attention of specialists, where the extraction of mineral raw materials is a significant sector of the economy. There are a significant amount of mineral ore dressability methods. At the moment the radiometric dressability methods are considered the most promising. One of radiometric methods is method photoluminescence. This method is based on the spectral analysis, amplitude and kinetic parameters luminescence of minerals (under UV radiation), as well as color parameters of radiation. The absence of developed scientific and methodological approaches of analysis irradiation area to UV radiation as well as absence the relevant radiation sources are the factors which hinder development and use of photoluminescence method. The present work is devoted to the development of multi-element UV radiation source designed for the solution problem of analysis and sorting minerals by their selective luminescence. This article is presented a method of theoretical modeling of the radiation devices based on UV LEDs. The models consider such factors as spectral component, the spatial and energy parameters of the LEDs. Also, this article is presented the results of experimental studies of the some samples minerals.

  6. Screening and monitoring microbial xenobiotics' biodegradation by rapid, inexpensive and easy to perform microplate UV-absorbance measurements.

    PubMed

    Herzog, Bastian; Lemmer, Hilde; Horn, Harald; Müller, Elisabeth

    2014-02-22

    Evaluation of xenobiotics biodegradation potential, shown here for benzotriazoles (corrosion inhibitors) and sulfamethoxazole (sulfonamide antibiotic) by microbial communities and/or pure cultures normally requires time intensive and money consuming LC/GC methods that are, in case of laboratory setups, not always needed. The usage of high concentrations to apply a high selective pressure on the microbial communities/pure cultures in laboratory setups, a simple UV-absorbance measurement (UV-AM) was developed and validated for screening a large number of setups, requiring almost no preparation and significantly less time and money compared to LC/GC methods. This rapid and easy to use method was evaluated by comparing its measured values to LC-UV and GC-MS/MS results. Furthermore, its application for monitoring and screening unknown activated sludge communities (ASC) and mixed pure cultures has been tested and approved to detect biodegradation of benzotriazole (BTri), 4- and 5-tolyltriazole (4-TTri, 5-TTri) as well as SMX. In laboratory setups, xenobiotics concentrations above 1.0 mg L(-1) without any enrichment or preparation could be detected after optimization of the method. As UV-AM does not require much preparatory work and can be conducted in 96 or even 384 well plate formats, the number of possible parallel setups and screening efficiency was significantly increased while analytic and laboratory costs were reduced to a minimum.

  7. Screening and monitoring microbial xenobiotics’ biodegradation by rapid, inexpensive and easy to perform microplate UV-absorbance measurements

    PubMed Central

    2014-01-01

    Background Evaluation of xenobiotics biodegradation potential, shown here for benzotriazoles (corrosion inhibitors) and sulfamethoxazole (sulfonamide antibiotic) by microbial communities and/or pure cultures normally requires time intensive and money consuming LC/GC methods that are, in case of laboratory setups, not always needed. Results The usage of high concentrations to apply a high selective pressure on the microbial communities/pure cultures in laboratory setups, a simple UV-absorbance measurement (UV-AM) was developed and validated for screening a large number of setups, requiring almost no preparation and significantly less time and money compared to LC/GC methods. This rapid and easy to use method was evaluated by comparing its measured values to LC-UV and GC-MS/MS results. Furthermore, its application for monitoring and screening unknown activated sludge communities (ASC) and mixed pure cultures has been tested and approved to detect biodegradation of benzotriazole (BTri), 4- and 5-tolyltriazole (4-TTri, 5-TTri) as well as SMX. Conclusions In laboratory setups, xenobiotics concentrations above 1.0 mg L-1 without any enrichment or preparation could be detected after optimization of the method. As UV-AM does not require much preparatory work and can be conducted in 96 or even 384 well plate formats, the number of possible parallel setups and screening efficiency was significantly increased while analytic and laboratory costs were reduced to a minimum. PMID:24558966

  8. Croconic acid - An absorber in the Venus clouds?

    NASA Technical Reports Server (NTRS)

    Hartley, Karen K.; Wolff, Andrew R.; Travis, Larry D.

    1989-01-01

    The absorbing species responsible for the UV cloud features and pale yellow hue of the Venus clouds is presently suggested to be the carbon monoxide-polymer croconic acid, which strongly absorbs in the blue and near-UV. Laboratory absorption-coefficient measurements of a dilute solution of croconic acid in sulfuric acid are used as the bases of cloud-scattering models; the Venus planetary albedo's observed behavior in the blue and near-UV are noted to be qualitatively reproduced. Attention is given to a plausible croconic acid-production mechanism for the Venus cloudtop region.

  9. Decontamination of poultry feed from ochratoxin A by UV and sunlight radiations.

    PubMed

    Ameer Sumbal, Gul; Hussain Shar, Zahid; Hussain Sherazi, Syed Tufail; Sirajuddin; Nizamani, Shafi Muhammad; Mahesar, Safaraz Ahmed

    2016-06-01

    Mycotoxin-contaminated feed is very dangerous for the growth and even life of poultry. The objective of the current study was to investigate the efficacy of ultra-violet irradiation for decontamination of ochratoxin A (OTA) in spiked and naturally contaminated poultry feed samples. Spiked and naturally contaminated feed samples were irradiated with ultra-violet light (UV) at distance of 25 cm over the feed samples. In vitro, the effect of UV intensity (0.1 mW cm(-2) at 254 nm UV-C) on different types of poultry feeds contaminated with OTA was evaluated. The same samples were also irradiated with sunlight and analysed for OTA by an indirect enzyme linked immunosorbent assay method. Poultry feed samples containing 500 µg kg(-1) were 100% decontaminated in 180 min with UV radiation while OTA was decreased to 70-95 µg kg(-1) using the same poultry feed samples after 8 h sunlight irradiation. Therefore, UV light was found to be more effective. Only 1 h of UV irradiation was found to be sufficient to bring the OTA level to the maximum regulatory limit suggested for poultry feeds (100 µg kg(-1) ), while 8 h were needed to obtain this level using sunlight radiations. The proposed approach is a viable option to reduce the level of OTA in contaminated poultry feeds. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

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

    NASA Astrophysics Data System (ADS)

    Terenetskaya, Irina; Orlova, Tatiana

    2005-09-01

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

  11. [Effects of silicon supply on diurnal variations of physiological properties at rice heading stage under elevated UV-B radiation].

    PubMed

    Wu, Lei; Lou, Yun-sheng; Meng, Yan; Wang, Wei-qing; Cui, He-yang

    2015-01-01

    A pot experiment was conducted to investigate the effects of silicon (Si) supply on diurnal variations of photosynthesis and transpiration-related physiological parameters at rice heading stage under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B. (ambient, A) and elevated UV-B (elevated by 20%, E), and four Si supply levels, i.e. Sio (control, 0 kg SiO2 . hm-2), Si, (sodium silicate, 100 kg SiO2 . hm-2), Si2 (sodium silicate, 200 kg SiO2 . hm2), Si3 (slag fertilizer, 200 kg SiO2 . hm-2). The results showed that, compared with ambient UV-B radiation, elevated UV-B radiation decreased the net photosynthesis rate (Pn) , intercellular CO2 concentration (Ci), transpiration rate (Tr), stomatal conductivity (gs) and water use efficiency (WUE) by 11.3%, 5.5%, 10.4%, 20.3% and 6.3%, respectively, in the treatment without Si supply (Si, level), and decreased the above parameters by 3.8%-5.5%, 0.7%-4.8%, 4.0%-8.7%, 7.4%-20.2% and 0.7%-5.9% in the treatments with Si supply (Si1, Si2 and Si3 levels) , respectively. Namely, elevated UV-B radiation decreased the photosynthesis and transpiration-related physiological parameters, but silicon supply could obviously mitigate the depressive effects of elevated UV-B radiation. Under elevated UV-B radiation, compared with control (Si0 level), silicon supply increased Pn, Ci, gs and WUE by 16.9%-28.0%, 3.5%-14.3%, 16.8% - 38.7% and 29.0% - 51.2%, respectively, but decreased Tr by 1.9% - 10.8% in the treatments with Si supply (Si1 , Si2 and Si3 levels). That is, silicon supply could mitigate the depressive effects of elevated UV-B radiation through significantly increasingnP., CigsgK and WUE, but decreasing T,. However, the difference existed in ameliorating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among the treatments of silicon supply, with the sequence of Si3>Si2>1i >Si0. This study suggested that fertilizing slag was

  12. The Martian and extraterrestrial UV radiation environment--1. Biological and closed-loop ecosystem considerations.

    PubMed

    Cockell, C S; Andrady, A L

    1999-01-01

    The Martian surface is exposed to both UVC radiation (<280 nm) and higher doses of UVB (280-315 nm) compared to the surface of the Earth. Terrestrial organisms have not evolved to cope with such high levels of UVC and UVB and thus any attempts to introduce organisms to Mars, particularly in closed-loop life support systems that use ambient sunlight, must address this problem. Here we examine the UV radiation environment of Mars with respect to biological systems. Action spectra and UV surface fluxes are used to estimate the UV stress that both DNA and chloroplasts would experience. From this vantage point it is possible to consider appropriate measures to address the problem of the Martian UV environment for future long term human exploration and settlement strategies. Some prospects for improving the UV tolerance of organisms are also discussed. Existing artificial ecosystems such as Biosphere 2 can provide some insights into design strategies pertinent to high UV environments. Some prospects for improving the UV tolerance of organisms are also discussed. The data also have implications for the establishment of closed-loop ecosystems using natural sunlight on the lunar surface and elsewhere in the Solar System.

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

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

  14. Study of long term effect of Solar UV and X-ray radiation on the VLF signals

    NASA Astrophysics Data System (ADS)

    Ray, Suman; Chakrabarti, Sandip Kumar; Sanki, Dipak

    2016-07-01

    Very Low Frequency (VLF) is one of the bands of Radio waves having frequencies lying between 3-30 KHz, with wavelengths 100-10 Km. It propagates through the Earth-ionosphere wave-guide which is formed by lower part of the ionosphere and upper part of Earth's surface. Ionosphere is the ionized component of upper atmosphere. In the present work, we have studied the long term effect of the high energy solar UV and X-ray radiation on the VLF signals. We have analyzed the VLF signal transmitted at 24 KHz from NAA (Cutler, Maine) and received at Moore Observatory in Brownsboro, Kentucky. Also we have collected X-ray and UV data to study the long term effect of UV and X-ray radiation on the VLF signal. We have analyzed the VLF signal for 2007 to 2015. We calculate the average diurnal peak amplitude of the VLF signal for each day and compare it with the UV and X-ray solar radiation. We found that the correlation coefficient of diurnal peak VLF signal amplitude with both solar X-ray and UV radiation is 0.7 indicating a strong correlation between these two phenomena.

  15. Radiative forcing and rapid adjustment of absorbing aerosols in the Pearl River Delta Region of China

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Yim, S. H. L.; Lau, G.

    2016-12-01

    Part of organic carbon defined as brown carbon (BrC) has been found to absorb solar radiation, especially in near-ultraviolet and blue bands, but their radiation impact is far less understood than black carbon (BC). Rapid adjustment thought to occur within a few weeks, induced by aerosol radiative effect and thereby alter cloud cover or other climate components. These effects are particularly pronounced for absorbing aerosols. The data gathered is from an online coupled model, WRF-Chem. A two-simulation test is conducted from July 8 to July 15. The baseline simulation doesn't account for aerosol-radiation interactions, whereas the sensitivity run includes it. The differences between these two simulations represent total effects of the aerosol instantaneous radiative forcing and subsequent rapid adjustment. In Figure 1, without cloud effect (clear sky), at the top of atmosphere (TOA), the SW radiation changes are negative in the PRD region, representing an overall cooling effect of aerosols. However, in the atmosphere (ATM), aerosols heat the atmosphere by absorbing incoming solar radiation with an average of 2.4 W/m2 (Table 1). After including rapid adjustment (all sky), the radiation change pattern becomes significantly different, especially at TOA and surface (SFC). This may be caused by cloud cover change due to rapid adjustment. The magnitude of SW radiation changes for all sky at all levels is smaller than that for clear sky. This result suggests the rapid adjustment counteracts the instantaneous radiative forcing of aerosols. At TOA, the cooling effect of the aerosol is 74% lower for all sky compared with clear sky, highlighting an overall warming effect of rapid adjustment in the PRD region. Aerosol-induced changes (W/m2) TOA ATM SFC Clear Sky -9.2 2.4 -11.6 All Sky -2.4 1.9 -4.3 Table 1. Aerosol-induced averaged changes in shortwave radiation due to aerosol-radiation interactions in the Pearl River Delta. The test shows the rapid adjustment of aerosols

  16. Radiation-damage-induced phasing: a case study using UV irradiation with light-emitting diodes.

    PubMed

    de Sanctis, Daniele; Zubieta, Chloe; Felisaz, Franck; Caserotto, Hugo; Nanao, Max H

    2016-03-01

    Exposure to X-rays, high-intensity visible light or ultraviolet radiation results in alterations to protein structure such as the breakage of disulfide bonds, the loss of electron density at electron-rich centres and the movement of side chains. These specific changes can be exploited in order to obtain phase information. Here, a case study using insulin to illustrate each step of the radiation-damage-induced phasing (RIP) method is presented. Unlike a traditional X-ray-induced damage step, specific damage is introduced via ultraviolet light-emitting diodes (UV-LEDs). In contrast to UV lasers, UV-LEDs have the advantages of small size, low cost and relative ease of use.

  17. Possible impacts of changes in UV-B radiation on North American trees and forests.

    PubMed

    Sullivan, Joe H

    2005-10-01

    Approximately 35 species representing 14 tree genera have been evaluated for responses to UV-B radiation in North America. The best representation has been in the conifers where some 20 species representing three genera have been studied. Overall, about 1/3 of these have demonstrated some deleterious response to UV-B. However, most negative impacts have been observed under controlled environment conditions where sensitivity may be enhanced. Therefore, it seems unlikely that expected levels of ozone depletion will result in direct losses in productivity. However, the role that ambient or enhanced levels of UV-B may play in forest ecosystem processes is more difficult to access. One possible indirect response of forests to changes in UV-B radiation levels could be via alterations in plant secondary metabolites. Increases in phenolics and flavonoids that enhance epidermal UV-screening effectiveness may also influence leaf development, water relations or ecosystem processes such as plant-herbivore interactions or decomposition.

  18. Potential of herbs in skin protection from ultraviolet radiation

    PubMed Central

    Korać, Radava R.; Khambholja, Kapil M.

    2011-01-01

    Herbs have been used in medicines and cosmetics from centuries. Their potential to treat different skin diseases, to adorn and improve the skin appearance is well-known. As ultraviolet (UV) radiation can cause sunburns, wrinkles, lower immunity against infections, premature aging, and cancer, there is permanent need for protection from UV radiation and prevention from their side effects. Herbs and herbal preparations have a high potential due to their antioxidant activity, primarily. Antioxidants such as vitamins (vitamin C, vitamin E), flavonoids, and phenolic acids play the main role in fighting against free radical species that are the main cause of numerous negative skin changes. Although isolated plant compounds have a high potential in protection of the skin, whole herbs extracts showed better potential due to their complex composition. Many studies showed that green and black tea (polyphenols) ameliorate adverse skin reactions following UV exposure. The gel from aloe is believed to stimulate skin and assist in new cell growth. Spectrophotometer testing indicates that as a concentrated extract of Krameria triandra it absorbs 25 to 30% of the amount of UV radiation typically absorbed by octyl methoxycinnamate. Sesame oil resists 30% of UV rays, while coconut, peanut, olive, and cottonseed oils block out about 20%. A “sclerojuglonic” compound which is forming from naphthoquinone and keratin is the reaction product that provides UV protection. Traditional use of plant in medication or beautification is the basis for researches and making new trends in cosmetics. This review covers all essential aspects of potential of herbs as radioprotective agents and its future prospects. PMID:22279374

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kochevar, I.E.

    1985-07-01

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

  20. Monitoring of environmental UV radiation by biological dosimeters

    NASA Astrophysics Data System (ADS)

    Rontó, Gy.; Bérces, A.; Gróf, P.; Fekete, A.; Kerékgyártó, T.; Gáspár, S.; Stick, C.

    As a consequence of the stratospheric ozone layer depletion biological systems can be damaged due to increased UV-B radiation. The aim of biological dosimetry is to establish a quantitative basis for the risk assessment of the biosphere. DNA is the most important target molecule of biological systems having special sensitivity against short wavelength components of the environmental radiation. Biological dosimeters are usually simple organisms, or components of them, modeling the cellular DNA. Phage T7 and polycrystalline uracil biological dosimeters have been developed and used in our laboratory for monitoring the environmental radiation in different radiation conditions (from the polar to equatorial regions). Comparisons with Robertson-Berger (RB) meter data, as well as with model calculation data weighted by the corresponding spectral sensitivities of the dosimeters are presented. Suggestion is given how to determine the trend of the increase in the biological risk due to ozone depletion.

  1. Effect of preparation and processing conditions on UV absorbing properties of hydroxyapatite-Fe2O3 sunscreen.

    PubMed

    C Teixeira, M A; Piccirillo, C; Tobaldi, D M; Pullar, R C; Labrincha, J A; Ferreira, M O; L Castro, P M; E Pintado, M M

    2017-02-01

    The development of innovative, safe and non-photocatalytic sunscreens is urgently needed, as it is essential to have sunscreen filters offering appropriate UV protection without damaging the environment and/or generating free radicals when in contact with the skin. Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 , HAp) when substituted with iron has UV protection properties and is not photocatalytic; HAp was used to make a sunscreen filter by treating cod fish bones in an iron-containing solution, and then calcining them at 700°C. Here we present a systematic and advanced study on this material, to obtain a sunscreen with improved UV absorbing properties. Bones were treated with three different iron salts - Fe(II) chloride, Fe(II) lactate and Fe(III) nitrate - under various pH conditions. Results showed that Fe(II) chloride in basic pH led to the most effective iron inclusion. High energy ball milling or ultrasound were investigated to increase surface area and corresponding UV absorption; high energy ball milling treatment led to the best optical properties. The optimum powders were used to formulate UV protection creams, which showed Sun Protection Factor (SPF) values significantly superior to the control cream (up to 4.1). Moreover the critical wavelength (λ crit ) was >370nm (388-389nm) and UVA/UVB ratios were very close to 1. With these properties these sunscreens can be classified as broad UV protectors. Results also showed that combining these powders with other sunscreens (i.e. titanium dioxide), a synergic effect between the different components was also observed. This investigation showed that HAp-based sunscreens of marine origin are a valid alternative to commercial products, safe for the health of the customers and, being non-photocatalytic, do not pose a threat to the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    PubMed

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

    2013-04-01

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

  3. Excision repair of UV radiation-induced DNA damage in Caenorhabditis elegans

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hartman, P.S.; Hevelone, J.; Dwarakanath, V.

    1989-06-01

    Radioimmunoassays were used to monitor the removal of antibody-binding sites associated with the two major UV radiation-induced DNA photoproducts (cyclobutane dimers and (6-4) photoproducts). Unlike with cultured human cells, where (6-4) photoproducts are removed more rapidly than cyclobutane dimers, the kinetics of repair were similar for both lesions. Repair capacity in wild type diminished throughout development. The radioimmunoassays were also employed to confirm the absence of photoreactivation in C. elegans. In addition, three radiation-sensitive mutants (rad-1, rad-2, rad-7) displayed normal repair capacities. An excision defect was much more pronounced in larvae than embryos in the fourth mutant tested (rad-3). Thismore » correlates with the hypersensitivity pattern of this mutant and suggests that DNA repair may be developmentally regulated in C. elegans. The mechanism of DNA repair in C. elegans as well as the relationship between the repair of specific photoproducts and UV radiation sensitivity during development are discussed.« less

  4. Impact of UV-B radiation on the digestive enzymes and immune system of larvae of Indian major carp Catla catla.

    PubMed

    Sharma, Jaigopal; Rao, Y Vasudeva; Kumar, S; Chakrabarti, Rina

    2010-03-01

    Ultraviolet radiation is a potent threat to the aquatic animals. Exposure to such stressor affects metabolic and immunological processes. The present investigation aims to study the effect of UV-B radiation on digestive enzymes and immunity of larvae of Catla catla. Larvae were exposed to ultraviolet-B (UV-B, 280-320 nm) radiation (145 microW/cm(2)) for three different exposure times of 5, 10 and 15 min on every other day. After 55 days, important digestive enzymes were assayed. For immunological study, lysozyme, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) levels were measured. Then the fish were kept for one month without radiation and lysozyme level was measured. Protein concentration varied directly with the duration of exposure and was highest among fish that had received the 15 min UV-B irradiation. Significantly higher amylase, protease, trypsin and chymotrypsin activities were found in 5 min exposed fish compared to others. Lysozyme level was significantly higher in control group compared to the UV-B treated fish. The lysozyme level decreased with the increasing duration of UV-B radiation. When fish were kept without UV-B radiation for one month, lysozyme level was brought to the normal level in all treatments, except 15 min exposed fish. The GOT and GPT levels were significantly higher in the 15 min exposed group than others. The effects of UV-B radiation on the digestive physiology and immune system of catla have been clearly observed in the present study. The decreased enzyme activities in UV-B radiated fish results into improper digestion and poor growth.

  5. Problems in Assessment of the UV Penetration into Natural Waters from Space-based Measurements

    NASA Technical Reports Server (NTRS)

    Vasilkov, Alexander P.; Herman, Jay; Krotkov, Nickolay A.; Kahru, Mati; Mitchell, B. Greg; Hsu, Christina; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Satellite instruments currently provide global maps of surface UV (ultraviolet) irradiance by combining backscattered radiance data with radiative transfer models. The models are often limited by uncertainties in physical input parameters of the atmosphere and surface. Global mapping of the underwater UV irradiance creates further challenges for the models. The uncertainties in physical input parameters become more serious because of the presence of absorbing and scattering quantities caused by biological processes within the oceans. In this paper we summarize the problems encountered in the assessment of the underwater UV irradiance from space-based measurements, and propose approaches to resolve the problems. We have developed a radiative transfer scheme for computation of the UV irradiance in the atmosphere-ocean system. The scheme makes use of input parameters derived from satellite instruments such as TOMS (Total Ozone Mapping Spectrometer) and SeaWiFS (Sea-viewing Wide Field-of-view Sensor). The major problem in assessment of the surface UV irradiance is to accurately quantify the effects of clouds. Unlike the standard TOMS UV algorithm, we use the cloud fraction products available from SeaWiFS and MODIS (Moderate Resolution Imaging Spectrometer) to calculate instantaneous surface flux at the ocean surface. Daily UV doses can be calculated by assuming a model of constant cloudiness throughout the day. Both SeaWiFS and MODIS provide some estimates of seawater optical properties in the visible. To calculate the underwater UV flux the seawater optical properties must be extrapolated down to shorter wavelengths. Currently, the problem of accurate extrapolation of visible data down to the UV spectral range is not solved completely, and there are few available measurements. The major difficulty is insufficient correlation between photosynthetic and photoprotective pigments of phytoplankton absorbing in the visible and UV respectively. We propose to empirically

  6. [Effects of silicon supply on rice growth and methane emission from paddy soil under elevated UV-B radiation].

    PubMed

    Meng, Yan; Lou, Yun-sheng; Wu, Lei; Cui, He-yang; Wang, Wei-qing

    2015-01-01

    A pot experiment was conducted to investigate the effects of silicon supply on rice growth and methane (CH4) emission in paddy field under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B (ambient, A) and elevated UV-B radiation (elevated by 20%, E) ; with four silicon supply levels, i.e., Si0 (control, without silicon), Si2 (as sodium silicate, 100 kg SiO2 . hm-2), Si2 (as sodium silicate, 200 kg SiO2 hm-2) and Si3 (as slag fertilizer, 200 kg SiO2 . hm-2). The results indicated that, silicon supply obviously alleviated the depressive effect of elevated UV-B radiation on rice growth, and increased the tiller numbers, chlorophyll content, and shoot and root dry masses. Silicon supply promoted rice growth, which increased with the silicon supply level (sodium silicate). Slag fertilizer was better than*sodium silicate in promoting rice growth. CH4 flux and accumulated CH4emission were obviously increased by elevated UV-B radiation, but significantly decreased by silicon application. CH4 emission was reduced with increasing the silicon supply level. Under the same silicon supply level, slag fertilizer was better than sodium silicate in inhibiting CH4 flux and accumulated CH4 emission. This research suggested that fertilizing slag in rice production was helpful not only in utilizing industrial wastes, but also in significantly mitigating CH4 emissions in rice paddy under elevated UV-B radiation.

  7. Light-Absorbing Brown Carbon Aerosol Constituents from Combustion of Indonesian Peat and Biomass.

    PubMed

    Budisulistiorini, Sri Hapsari; Riva, Matthieu; Williams, Michael; Chen, Jing; Itoh, Masayuki; Surratt, Jason D; Kuwata, Mikinori

    2017-04-18

    Light-absorbing brown carbon (BrC) constituents of organic aerosol (OA) have been shown to significantly absorb ultraviolet (UV) and visible light and thus impact radiative forcing. However, molecular identification of the BrC constituents is still limited. In this study, we characterize BrC constituents at the molecular level in (i) aerosols emitted by combustion of peat, fern/leaf, and charcoal from Indonesia and (ii) ambient aerosols collected in Singapore during the 2015 haze episode. Aerosols were analyzed using ultra performance liquid chromatography instrument interfaced to a diode array detector and electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in the negative ion mode. In the laboratory-generated aerosols, we identified 41 compounds that can potentially absorb near-UV and visible wavelengths, such as oxygenated-conjugated compounds, nitroaromatics, and S-containing compounds. The sum of BrC constituents in peat, fern/leaf, and charcoal burning aerosols are 16%, 35%, and 28% of the OA mass, respectively, giving an average contribution of 24%. On average, the BrC constituents account for 0.4% of the ambient OA mass; however, large uncertainties in mass closure remain because of the lack of authentic standards. This study highlights the potential of light-absorbing BrC OA constituents from peat, fern/leaf, and charcoal burning and their importance in the atmosphere.

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

    PubMed

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

    2017-11-01

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

  9. Alteration of foliar flavonoid chemistry induced by enhanced UV-B radiation in field-grown Pinus ponderosa, Quercus rubra and Pseudotsuga menziesii.

    PubMed

    Warren, Jeffrey M; Bassman, John H; Mattinson, D Scott; Fellman, John K; Edwards, Gerald E; Robberecht, Ronald

    2002-03-01

    Chromatographic analyses of foliage from several tree species illustrate the species-specific effects of UV-B radiation on both quantity and composition of foliar flavonoids. Pinus ponderosa, Quercus rubra and Pseudotsuga menziesii were field-grown under modulated ambient (1x) and enhanced (2x) biologically effective UV-B radiation. Foliage was harvested seasonally over a 3-year period, extracted, purified and the flavonoid fraction applied to a mu Bondapak/C(18) column HPLC system sampling at 254 nm. Total flavonoid concentrations in Quercus rubra foliage were more than twice (leaf area basis) that of the other species; Pseudotsuga menziesii foliage had intermediate levels and P. ponderosa had the lowest concentrations of total flavonoids. No statistically significant UV-B radiation-induced effects were found in total foliar flavonoid concentrations for any species; however, concentrations of specific compounds within each species exhibited significant treatment effects. Higher (but statistically insignificant) levels of flavonoids were induced by UV-B irradiation in 1- and 2-year-old P. ponderosa foliage. Total flavonoid concentrations in 2-year-old needles increased by 50% (1x ambient UV-B radiation) or 70% (2x ambient UV-B radiation) from that of 1-year-old tissue. Foliar flavonoids of Q. rubra under enhanced UV-B radiation tended to shift from early-eluting compounds to less polar flavonoids eluting later. There were no clear patterns of UV-B radiation effects on 1-year-old P. menziesii foliage. However, 2-year-old tissue had slightly higher foliar flavonoids under the 2x UV-B radiation treatment compared to ambient levels. Results suggest that enhanced UV-B radiation will alter foliar flavonoid composition and concentrations in forest tree species, which could impact tissue protection, and ultimately, competition, herbivory or litter decomposition.

  10. The novel cyclophilin D inhibitor compound 19 protects retinal pigment epithelium cells and retinal ganglion cells from UV radiation.

    PubMed

    Xie, Laiqing; Cheng, Long; Xu, Guoxu; Zhang, Ji; Ji, Xiaoyan; Song, E

    2017-06-10

    Excessive Ultra violet (UV) radiation induces injuries to retinal pigment epithelium (RPE) cells (RPEs) and retinal ganglion cells (RGCs), causing retinal degeneration. Cyclophilin D (Cyp-D)-dependent mitochondrial permeability transition pore (mPTP) opening mediates UV-induced cell death. In this study, we show that a novel Cyp-D inhibitor compound 19 efficiently protected RPEs and RGCs from UV radiation. Compound 19-mediated cytoprotection requires Cyp-D, as it failed to further protect RPEs/RGCs from UV when Cyp-D was silenced by targeted shRNAs. Compound 19 almost blocked UV-induced p53-Cyp-D mitochondrial association, mPTP opening and subsequent cytochrome C release. Further studies showed that compound 19 inhibited UV-induced reactive oxygen species (ROS) production, lipid peroxidation and DNA damage. Together, compound 19 protects RPEs and RGCs from UV radiation, possibly via silencing Cyp-D-regulated intrinsic mitochondrial death pathway. Compound 19 could a lead compound for treating UV-associated retinal degeneration diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Stephan, Ryan; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2012-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 m2 radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduces the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  12. Integration and scaling of UV-B radiation effects on plants: from molecular interactions to whole plant responses.

    PubMed

    Suchar, Vasile Alexandru; Robberecht, Ronald

    2016-07-01

    A process based model integrating the effects of UV-B radiation to molecular level processes and their consequences to whole plant growth and development was developed from key parameters in the published literature. Model simulations showed that UV-B radiation induced changes in plant metabolic and/or photosynthesis rates can result in plant growth inhibitions. The costs of effective epidermal UV-B radiation absorptive compounds did not result in any significant changes in plant growth, but any associated metabolic costs effectively reduced the potential plant biomass. The model showed significant interactions between UV-B radiation effects and temperature and any factor leading to inhibition of photosynthetic production or plant growth during the midday, but the effects were not cumulative for all factors. Vegetative growth were significantly delayed in species that do not exhibit reproductive cycles during a growing season, but vegetative growth and reproductive yield in species completing their life cycle in one growing season did not appear to be delayed more than 2-5 days, probably within the natural variability of the life cycles for many species. This is the first model to integrate the effects of increased UV-B radiation through molecular level processes and their consequences to whole plant growth and development.

  13. The Protective Role of Melanin Against UV Damage in Human Skin

    PubMed Central

    Brenner, Michaela; Hearing, Vincent J.

    2009-01-01

    Human skin is repeatedly exposed to ultraviolet radiation (UVR) that influences the function and survival of many cell types and is regarded as the main causative factor in the induction of skin cancer. It has been traditionally believed that skin pigmentation is the most important photoprotective factor, since melanin, besides functioning as a broadband UV absorbent, has antioxidant and radical scavenging properties. Besides, many epidemiological studies have shown a lower incidence for skin cancer in individuals with darker skin compared to those with fair skin. Skin pigmentation is of great cultural and cosmetic importance, yet the role of melanin in photoprotection is still controversial. This article outlines the major acute and chronic effects of UV radiation on human skin, the properties of melanin, the regulation of pigmentation and its effect on skin cancer prevention. PMID:18435612

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

    PubMed

    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.

  15. The UV-absorber benzophenone-4 alters transcripts of genes involved in hormonal pathways in zebrafish (Danio rerio) eleuthero-embryos and adult males

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zucchi, Sara; Bluethgen, Nancy; University of Basel, Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, Klingelbergstrasse 50, CH-4056 Basel

    Benzophenone-4 (BP-4) is frequently used as UV-absorber in cosmetics and materials protection. Despite its frequent detection in the aquatic environment potential effects on aquatic life are unknown. In this study, we evaluate the effects of BP-4 in eleuthero-embryos and in the liver, testis and brain of adult male fish on the transcriptional level by focusing on target genes involved in hormonal pathways to provide a more complete toxicological profile of this important UV-absorber. Eleuthero-embryos and males of zebrafish were exposed up to 3 days after hatching and for 14 days, respectively, to BP-4 concentrations between 30 and 3000 {mu}g/L. Inmore » eleuthero-embryos transcripts of vtg1, vtg3, esr1, esr2b, hsd17ss3, cyp19b cyp19a, hhex and pax8 were induced at 3000 {mu}g/L BP-4, which points to a low estrogenic activity and interference with early thyroid development, respectively. In adult males BP-4 displayed multiple effects on gene expression in different tissues. In the liver vtg1, vtg3, esr1 and esr2b were down-regulated, while in the brain, vtg1, vtg3 and cyp19b transcripts were up-regulated. In conclusion, the transcription profile revealed that BP-4 interferes with the expression of genes involved in hormonal pathways and steroidogenesis. The effects of BP-4 differ in life stages and adult tissues and point to an estrogenic activity in eleuthero-embryos and adult brain, and an antiestrogenic activity in the liver. The results indicate that BP-4 interferes with the sex hormone system of fish, which is important for the risk assessment of this UV-absorber.« less

  16. Fate of Earth Microbes on Mars: UV Radiation Effects

    NASA Technical Reports Server (NTRS)

    Cockell, Charles

    2000-01-01

    A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment. Biological action spectra for DNA inactivation are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Although the present-day martian UV flux is similar to early earth and thus may not be a limitation to life in the evolutionary context, it is a constraint to an unadapted biota and will rapidly kill spacecraft-borne microbes not covered by a martian dust layer. Here calculations for loss of microbial viability on the Pathfinder and Polar lander spacecraft are presented and the effects of martian dust on loss of viability are discussed. Details of the radiative transfer model are presented.

  17. Fate of Earth Microbes on Mars -- UV Radiation Effects

    NASA Technical Reports Server (NTRS)

    Cockell, Charles

    2000-01-01

    A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment. Biological action spectra for DNA inactivation are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Although the present-day martian UV flux is similar to early earth and thus may not be a limitation to life in the evolutionary context, it is a constraint to an unadapted biota and will rapidly kill spacecraft-borne microbes not covered by a martian dust layer. Here calculations for loss of microbial viability on the Pathfinder and Polar lander spacecraft are presented and the effects of martian dust on loss of viability are discussed. Details of the radiative transfer model are presented.

  18. The influence of UV radiation on protistan evolution

    NASA Technical Reports Server (NTRS)

    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.

  19. Feasibility of the silver-UV process for drinking water disinfection.

    PubMed

    Butkus, Michael A; Talbot, Mark; Labare, Michael P

    2005-12-01

    A synergistic effect between cationic silver and UV radiation (silver-UV disinfection) has been observed that can appreciably enhance inactivation of viruses. The purpose of this work was to assess the feasibility of this technique for drinking water disinfection and evaluate the effects of selected impurities, found in fresh water, and common parameters on inactivation of the coliphage MS-2 with the silver-UV process. Turbidity (kaolin), calcium hardness, carbonate alkalinity, and pH did not significantly degrade inactivation. Inactivation was reduced in the presence of chloride, at concentrations greater than 30 mg/L, and in water samples with UV-254 absorbance values greater than ca. 0.1 cm(-1). Inactivation of MS-2 with silver-UV disinfection was also reduced at high phosphate concentrations (above ca. 5 mM). Silver-UV inactivation of MS-2 increased with increases in temperature between 10 and 20 degrees C. Silver-UV inactivation of MS-2 was increased by greater than 1-log over UV alone, in two untreated fresh water sources, which indicates that silver-UV may be a viable treatment technology. An assessment of operation and management costs suggests that an increase in inactivation of MS-2 with silver-UV disinfection could be economically beneficial.

  20. LEAF UV OPTICAL PROPERTIES OF 'RUMEX PATIENTIA' L. AND 'RUMEX OBTUSIFOLIUS L. IN REGARD TO A PROTECTIVE MECHANISM AGAINST SOLAR UV-B RADIATION INJURY

    EPA Science Inventory

    Effective UV attenuation in the outer leaf layers may represent an important protective mechanism against potentially damaging solar UV-B radiation. Epidermal optical properties for Rumex patientia and Rumex obtusifolius were examined on field collected and greenhouse grown plant...

  1. Enhanced resistance of the Pamirs high-mountain strain of Cryptococcus albidus to UV radiation of an ecological range

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Strakhovskaya, M.G.; Lavrukhina, O.G.; Fraikin, G.Y.

    The results of a comparative analysis of the resistance of Pamirs high-mountain and lowland strains of the yeast Cryptococcus albidus to UV radiation of an ecological range are presented. A high-mountain strain, adapted to elevated UV radiation in its habitat, was found to be more resistant to UV light of a total ecorange (290-400 nm), including medium-wave (290-320 nm) and long-wave (320-400 nm) UV ranges. The enhanced UV light resistance of the high-mountain strain can be explained by efficient functioning of the excision DNA repair system. 7 refs., 3 tabs.

  2. UV-induced DNA damage is an intermediate step in UV-induced expression of human immunodeficiency virus type 1, collagenase, c-fos, and metallothionein.

    PubMed Central

    Stein, B; Rahmsdorf, H J; Steffen, A; Litfin, M; Herrlich, P

    1989-01-01

    UV irradiation of human and murine cells enhances the transcription of several genes. Here we report on the primary target of relevant UV absorption, on pathways leading to gene activation, and on the elements receiving the UV-induced signal in the human immunodeficiency virus type 1 (HIV-1) long terminal repeat, in the gene coding for collagenase, and in the cellular oncogene fos. In order to induce the expression of genes. UV radiation needs to be absorbed by DNA and to cause DNA damage of the kind that cannot be repaired by cells from patients with xeroderma pigmentosum group A. UV-induced activation of the three genes is mediated by the major enhancer elements (located between nucleotide positions -105 and -79 of HIV-1, between positions -72 and -65 of the collagenase gene, and between positions -320 and -299 of fos). These elements share no apparent sequence motif and bind different trans-acting proteins; a member of the NF kappa B family binds to the HIV-1 enhancer, the heterodimer of Jun and Fos (AP-1) binds to the collagenase enhancer, and the serum response factors p67 and p62 bind to fos. DNA-binding activities of the factors recognizing the HIV-1 and collagenase enhancers are augmented in extracts from UV-treated cells. The increase in activity is due to posttranslational modification. While AP-1 resides in the nucleus and must be modulated there, NF kappa B is activated in the cytoplasm, indicating the existence of a cytoplasmic signal transduction pathway triggered by UV-induced DNA damage. In addition to activation, new synthesis of AP-1 is induced by UV radiation. Images PMID:2557547

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

    PubMed

    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. Colour change evaluation on UV radiation exposure for Păun-Repedea calcareous geomaterial

    NASA Astrophysics Data System (ADS)

    Pelin, V.; Sandu, I.; Munteanu, M.; Iurcovschi, C. T.; Gurlui, S.; Sandu, AV; Vasilache, V.; Brȃnzilă, M.; Sandu, I. G.

    2016-06-01

    When talking about the preservation treatments that can be applied to natural stones used in different constructions, the surface hydrophobization plays an important part, especially when referring to porous surfaces like the calcareous oolithic stones specific to Repedea area, Iasi County, Romania. The present paper presents a method that evaluates the hydrophobization efficiency of two types of pellicles, involving UV artificial ageing and colorimetric analysis of the treated surfaces. The evaluation was done through continuous colorimetric monitoring and by comparing the evolution of the chromatic modifications of the two treated surfaces with the original colorimetric values and with the witness area, which was exposed to UV radiations under the same conditions, but left chemical untreated. The techniques used during this experiment were: CIE L*a*b* colorimetry, OM, SEM-EDX, UV radiation exposure and Spectrum Irradiance Measurement.

  5. Gene Expression Profiling in Response to Ultraviolet Radiation in Maize Genotypes with Varying Flavonoid Content1[w

    PubMed Central

    Casati, Paula; Walbot, Virginia

    2003-01-01

    Microarray hybridization was used to assess acclimation responses to four UV regimes by near isogenic maize (Zea mays) lines varying in flavonoid content. We found that 355 of the 2,500 cDNAs tested were regulated by UV radiation in at least one genotype. Among these, 232 transcripts are assigned putative functions, whereas 123 encode unknown proteins. UV-B increased expression of stress response and ribosomal protein genes, whereas photosynthesis-associated genes were down-regulated; lines lacking UV-absorbing pigments had more dramatic responses than did lines with these pigments, confirming the shielding role of these compounds. Sunlight filtered to remove UV-B or UV-B plus UV-A resulted in significant expression changes in many genes not previously associated with UV responses. Some pathways regulated by UV radiation are shared with defense, salt, and oxidative stresses; however, UV-B radiation can activate additional pathways not shared with other stresses. PMID:12913132

  6. The formation of ozone and UV radiation from high-power pulsed electric discharges

    NASA Astrophysics Data System (ADS)

    Piskarev, I. M.; Ushkanov, V. A.; Selemir, V. D.; Spirov, G. M.; Malevannaya Pikar', I. A.; Zuimach, E. A.

    2008-09-01

    High-power electric discharges with pulse energies of from 0.15 J to 4 kJ were studied. The yields of UV photons and ozone were found to be approximately equal, which led us to conclude that discharge conditions under which UV radiation and ozone fully destroyed each other were possible. If ozone formation was suppressed, as when a negative volume charge was created in the spark gap region, the flux of UV photons reached 3 × 1023 photons/(cm2 s).

  7. The PUR Experiment on the EXPOSE-R facility: biological dosimetry of solar extraterrestrial UV radiation

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Egyeki, M.; Fekete, A.; Horneck, G.; Kovács, G.; Panitz, C.

    2015-01-01

    The aim of our experiment Phage and Uracil Response was to extend the use of bacteriophage T7 and uracil biological dosimeters for measuring the biologically effective ultraviolet (UV) dose in the harsh extraterrestrial radiation conditions. The biological detectors were exposed in vacuum-tightly cases in the European Space Agency (ESA) astrobiological exposure facility attached to the external platform of Zvezda (EXPOSE-R). EXPOSE-R took off to the International Space Station (ISS) in November 2008 and was installed on the External platform of the Russian module Zvezda of the ISS in March 2009. Our goal was to determine the dose-effect relation for the formation of photoproducts (i.e. damage to phage DNA and uracil, respectively). The extraterrestrial solar UV radiation ranges over the whole spectrum from vacuum-UV (λ<200 nm) to UVA (315 nm<λ<400 nm), which causes photolesions (photoproducts) in the nucleic acids/their components either by photoionization or excitation. However, these wavelengths cause not only photolesions but in a wavelength-dependent efficiency the reversion of some photolesions, too. Our biological detectors measured in situ conditions the resultant of both reactions induced by the extraterrestrial UV radiation. From this aspect the role of the photoreversion in the extension of the biological UV dosimetry are discussed.

  8. Long-term variability and impact on human health of biologically active UV radiation in Moscow

    NASA Astrophysics Data System (ADS)

    Zhdanova, Ekaterina; Chubarova, Natalia

    2014-05-01

    Measurements of erythemally weighted UV irradiance (Qer) have been performed at the Meteorological Observatory of Moscow State University since 1999 with the UVB-1 YES pyranometers. These types of devices are broadband with a spectral sensitivity curve close to the action spectrum of erythema. Main uncertainties of UVB-1 YES measurements include the difference in spectral curves of the instrument and the action spectrum of erythema, as well as the deviation from the cosine law. These uncertainties were taken into account in the database of Qer measurements (Chubarova, 2008. Additional corrections of UVB-1 measurements at low ambient temperatures have been made. We analyze interannual, seasonal and diurnal Qer changes over the time period 1999-2012. In addition, the comparisons with the results of UV reconstruction model (Chubarova, 2008) are made. This model allows us to evaluate relative changes in Qer due to variations in total ozone, effective cloud amount transmission, aerosol and cloud optical thickness since 1968. It is important to note that the main reason for UV irradiance monitoring development is the strong influence of UV irradiance on the biosphere and especially on human health mainly on human skin (CIE, 1993, CIE, 2006) and eyes (Oriowo, M. et al., 2001). Based on the detailed studies we have shown the possibility of utilizing UVB-1 pyranometers for measuring the eye-damage UV radiation. Parallel measurements by the Bentham DTM-300 spectrometer and the UVB-1 YES pyranometer at the Innsbruck Medical University (Austria) have provided us the calibration factor in eye-damage units for this broadband instrument. Influence of main geophysical factors on different types of UV irradiance is estimated by means the RAF ideology (Booth, Madronich, 1994). We discuss the responses of different types of biologically active UV radiation to the impact of various atmospheric factors. The UV conditions (deficiency, optimum, excess for human) are analyzed according to

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

    PubMed

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

    2011-08-01

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

  10. Motility and gravitactic orientation of the flagellate, Euglena gracilis, impaired by artificial and solar UV-B radiation.

    PubMed

    Hader, D P; Liu, S M

    1990-09-01

    The effects of ultraviolet radiation on the gravitactic orientation of the freshwater flagellate, Euglena gracilis, were determined by a real time image analysis system. Both artificial UV radiation and solar radiation in a temperature-controlled growth chamber were employed. Histograms of gravitaxis showed that the degree of orientation decreased with increasing exposure time; this can be quantified using the Rayleigh test and upper quadrant summation. The effects of artificial UV radiation on the orientation are considerably stronger than those of solar radiation, probably because the radiation source emits higher fluence rates below 300 nm than found in solar radiation. The effects of monochromatic ultraviolet radiation on motility have been determined, and an action spectrum has been calculated.

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

    PubMed

    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 < 0.05). UV radiation combining 60 °C hot water treatment increased inactivation of C. sakazakii cells significantly (P < 0.05) in reconstituted infant formula. Significant effects of UV 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®

  12. Cell damage caused by ultraviolet B radiation in the desert cyanobacterium Phormidium tenue and its recovery process.

    PubMed

    Wang, Gaohong; Deng, Songqiang; Liu, Jiafeng; Ye, Chaoran; Zhou, Xiangjun; Chen, Lanzhou

    2017-10-01

    Phormidium tenue, a cyanobacterium that grows in the topsoil of biological soil crusts (BSCs), has the highest recovery rate among desert crust cyanobacteria after exposure to ultraviolet B (UV-B) radiation. However, the mechanism underlying its recovery process is unclear. To address this issue, we measured chlorophyll a fluorescence, generation of reactive oxygen species (ROS), lipid peroxidation, and repair of DNA breakage in P. tenue following exposure to UV-B. We found that UV-B radiation at all doses tested reduced photosynthesis and induced cell damage in P. tenue. However, P. tenue responded to UV-B radiation by rapidly reducing photosynthetic activity, which protects the cell by leaking less ROS. Antioxidant enzymes, DNA damage repair systems, and UV absorbing pigments were then induced to mitigate the damage caused by UV-B radiation. The addition of exogenous antioxidant chemicals ascorbate and N-acetylcysteine also mitigated the harmful effects caused by UV-B radiation and enhanced the recovery process. These chemicals could aid in the resistance of P. tenue to the exposure of intense UV-B radiation in desertified areas when inoculated onto the sand surface to form artificial algal crusts. Copyright © 2017. Published by Elsevier Inc.

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

    PubMed

    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.

  14. A Fast Hyperspectral Vector Radiative Transfer Model in UV to IR spectral bands

    NASA Astrophysics Data System (ADS)

    Ding, J.; Yang, P.; Sun, B.; Kattawar, G. W.; Platnick, S. E.; Meyer, K.; Wang, C.

    2016-12-01

    We develop a fast hyperspectral vector radiative transfer model with a spectral range from UV to IR with 5 nm resolutions. This model can simulate top of the atmosphere (TOA) diffuse radiance and polarized reflectance by considering gas absorption, Rayleigh scattering, and aerosol and cloud scattering. The absorption component considers several major atmospheric absorbers such as water vapor, CO2, O3, and O2 including both line and continuum absorptions. A regression-based method is used to parameterize the layer effective optical thickness for each gas, which substantially increases the computation efficiency for absorption while maintaining high accuracy. This method is over 500 times faster than the existing line-by-line method. The scattering component uses the successive order of scattering (SOS) method. For Rayleigh scattering, convergence is fast due to the small optical thickness of atmospheric gases. For cloud and aerosol layers, a small-angle approximation method is used in SOS calculations. The scattering process is divided into two parts, a forward part and a diffuse part. The scattering in the small-angle range in the forward direction is approximated as forward scattering. A cloud or aerosol layer is divided into thin layers. As the ray propagates through each thin layer, a portion diverges as diffuse radiation, while the remainder continues propagating in forward direction. The computed diffuse radiance is the sum of all of the diffuse parts. The small-angle approximation makes the SOS calculation converge rapidly even in a thick cloud layer.

  15. Free-Free Radiation Cannot Make the UV/Soft-X-Ray Excess in AGN

    NASA Astrophysics Data System (ADS)

    Kriss, G. A.

    1994-05-01

    Thermal gas always has associated atomic spectral features either in absorption or in emission. In optically thin gas the emission spectrum is dominated by line radiation and recombination continua. An example of radiation from optically thin material in accreting systems is the emission-line-dominated spectrum of a cataclysmic variable in its low state. Barvainis (1993, ApJ, 412, 513) and others have proposed that the UV/soft-X-ray excess prominent in the spectra of many AGN is due to free-free emission from gas at temperatures of 10(5) - 10(6) K. Simple arguments using only atomic data show that the recombination radiation from emission lines would produce UV, optical, and soft X-ray spectral features orders of magnitude stronger than observed. Collisional excitation produces even more line radiation under most physical conditions. As a particular example I take the Astro-1 observations of the Seyfert 1 galaxy Mrk 335 by HUT and BBXRT. Depending on the ionization state of the gas (which may be photoionized by the central source), the emission measure of the free-free radiation necessary to produce the UV continuum (3 times 10(68) cm(-3) at 8.2 times 10(5) K for H_o = 75 km s(-1) Mpc(-1) ) implies line emission from O VI, O VII, or O VIII more than a factor of 10 stronger than any features observed by HUT or BBXRT.

  16. DNA damage and repair in plants under ultraviolet and ionizing radiations.

    PubMed

    Gill, Sarvajeet S; Anjum, Naser A; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315-400 nm; UV-B, 280-315 nm; and UV-C, <280 nm) is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH(•)) and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  17. DNA Damage and Repair in Plants under Ultraviolet and Ionizing Radiations

    PubMed Central

    Gill, Sarvajeet S.; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315–400 nm; UV-B, 280–315 nm; and UV-C, <280 nm) is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH•) and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context. PMID:25729769

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

    NASA Astrophysics Data System (ADS)

    Kujanpää, J.; Kalakoski, N.

    2015-05-01

    The surface ultraviolet (UV) radiation product, version 1.20, generated operationally in the framework of the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) is described. The product is based on the total ozone column derived from the measurements of the second Global Ozone Monitoring Experiment (GOME-2) instrument aboard EUMETSAT's polar orbiting meteorological operational (Metop) satellites. The input total ozone product is generated by the German Aerospace Center (DLR) also within the O3M SAF framework. Polar orbiting satellites provide global coverage but infrequent sampling of the diurnal cloud cover. The diurnal variation of the surface UV radiation is extremely strong due to modulation by solar elevation and rapidly changing cloud cover. At the minimum, one sample of the cloud cover in the morning and another in the afternoon are needed to derive daily maximum and daily integrated surface UV radiation quantities. This is achieved by retrieving cloud optical depth from the channel 1 reflectance of the third Advanced Very High Resolution Radiometer (AVHRR/3) instrument aboard both Metop in the morning orbit (daytime descending node around 09:30 LT) and Polar Orbiting Environmental Satellites (POES) of the National Oceanic and Atmospheric Administration (NOAA) in the afternoon orbit (daytime ascending node around 14:30 LT). In addition, more overpasses are used at high latitudes where the swaths of consecutive orbits overlap. The input satellite data are received from EUMETSAT's Multicast Distribution System (EUMETCast) using commercial telecommunication satellites for broadcasting the data to the user community. The surface UV product includes daily maximum dose rates and integrated daily doses with different biological weighting functions, integrated UVB and UVA radiation, solar noon UV Index and daily maximum photolysis

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    Introduction: RISC-UV is a research project on "Impact of climate change on ultraviolet radiation and risks for health", a research project in which physicists, meteorologists and physicians work together to assess the relative role played by environmental and behavioral factors in the UV-related diseases as skin cancer and vitamin D deficiency. Environmental factors are related to the role played by the alteration in intensity of UV radiation at the Earth's surface resulting from variation in several factors affected by climate change and human activities: stratospheric ozone, cloud cover, aerosols and the reflectivity of the surface. On the other hand, behavioral factors are related to the sun over/underexposure and the correct use of sun-protection (hats, caps, sunglasses, sunscreen lotion, etc.). RISC-UV is organized around three main areas: 1) Organization of a workshop, scheduled for January 2009, which aims to describe the state of the art in the subject within each community and define the requirements of pathologists for epidemiological studies; 2) A pilot study intended to evaluate the consistency between UV measurements delivered simultaneously by satellite-based instruments, ground instruments, radiometers and individual dosimeters. This study is based on measurements campaigns and an analysis of the long-term consistency of data series relating to UV radiation and associated parameters; and 3) Analysis of the weights of medical, behavioral and environmental parameters involved in skin carcinogenesis. A detailed description of these areas can be found in http://www.gisclimat.fr/Doc/GB/D_projects/RISC-UV_GB.html. This presentation focuses on the first results of the UV experimental measurements performed between September 8th and October 8th 2008 in Palaiseau, France (48.7˚ N; 2.2˚ E; 170m - Haeffelin et al., 2005). A second campaign is foreseen for the spring of 2009. The purpose of these campaigns is to obtain, analyze and quantitatively link the

  20. Blue light and solar UV radiation accelerate spring and autumn phenology in temperate deciduous tree species.

    NASA Astrophysics Data System (ADS)

    Brelsford, C.; Robson, T. M.

    2017-12-01

    Trees utilise multiple cues to time their bud-burst and leaf out in spring so that they can exploit favorable conditions for photosynthesis but minimize the risk of damage, and time their leaf senescence come autumn to extend the period of carbon assimilation and remobilize nutrients as efficiently as possible. Whilst the effects of temperature and photoperiod on phenology have been well studied, the effect of light quality is not often considered. The amount and proportion of blue light (BL 400-500nm), UV-A (325-400nm), and UV-B (290-320nm) reaching the ground changes with latitude, day length and the time of year, and yet little is known about how this affects the phenology of plants. We hypothesize that these compositional changes can be exploited by temperate deciduous tree species as cues for bud-burst and leaf senescence via blue and UV photoreceptors. To test this hypothesis, we measured the days until bud-burst of dormant branches from trees of Alnus glutinosa, Betula pendula, and Quercus robur when grown under a broad spectrum, either including or without BL, but of equivalent PAR. We also monitored the spring and autumn leaf phenology of Acer platanoides seedlings growing under forest canopies in southern Finland, under filter treatments attenuating UV-A radiation, UV-A + UV-B radiation or BL and UV-A and UV-B radiation, and a transparent control filter. In controlled conditions, BL advanced bud-burst by 3.3 days in branches of B.pendula, 6 days in A.glutinosa, and 6.3 days in Q.robur. In the field experiment, BL promoted bud burst of A.platanoides seedlings by 3 days. Leaf senescence was promoted by up to 16 days with BL, and by at least 3 days by UV-A and UV-B. The effect of BL in reducing the number of days until bud burst was greatest in later successional species. Furthermore, both blue light and UV advanced leaf senescence in autumn. Further research is needed to identify the photoreceptor mechanisms that underpin these physiological processes, and

  1. Radiation absorbed dose estimates for 18F-BPA PET.

    PubMed

    Kono, Yuzuru; Kurihara, Hiroaki; Kawamoto, Hiroshi; Yasui, Naoko; Honda, Naoki; Igaki, Hiroshi; Itami, Jun

    2017-09-01

    Background Boron neutron capture therapy (BNCT) is a molecular radiation therapy approach based on the 10 B (n, α) 7 Li nuclear reaction in cancer cells. In BNCT, delivery of 10 B in the form of 4-borono-phenylalanine conjugated with fructose (BPA-fr) to the cancer cells is important. The PET tracer 4-borono-2-18F-fluoro-phenylalanine (FBPA) has been used to predict the accumulation of BPA-fr before BNCT. Purpose To determine the biodistribution and dosimetric parameters in 18F-BPA PET/CT studies. Material and Methods Human biokinetic data were obtained during clinical 18F-BPA PET studies between February and June 2015 at one institution. Nine consecutive patients were studied prospectively. The internal radiation dose was calculated on the basis of radioactivity data from blood, urine, and normal tissue of the heart, liver, spleen, kidney, and other parts of the body at each time point using OLINDA/EXM1.1 program. We compared our calculations with published 18F-FDG data. Results Adult patients (3 men, 3 women; age range, 28-68 years) had significantly smaller absorbed doses than pediatric patients (3 patients; age range, 5-12 years) ( P = 0.003). The mean effective dose was 57% lower in adult patients compared with pediatric patients. Mean effective doses for 18F-BPA were 25% lower than those for 18F-FDG presented in International Commission of Radiation Protection (ICRP) publication 106. Conclusion We found significant differences in organ absorbed doses for 18F-BPA against those for 18F-FDG presented in ICRP publication 106. Mean effective doses for 18F-BPA were smaller than those for 18F-FDG in the publication by 0.5-38% (mean difference, 25%).

  2. DirtyGrid I: 3D Dust Radiative Transfer Modeling of Spectral Energy Distributions of Dusty Stellar Populations

    NASA Astrophysics Data System (ADS)

    Law, Ka-Hei; Gordon, Karl D.; Misselt, Karl A.

    2018-06-01

    Understanding the properties of stellar populations and interstellar dust has important implications for galaxy evolution. In normal star-forming galaxies, stars and the interstellar medium dominate the radiation from ultraviolet (UV) to infrared (IR). In particular, interstellar dust absorbs and scatters UV and optical light, re-emitting the absorbed energy in the IR. This is a strongly nonlinear process that makes independent studies of the UV-optical and IR susceptible to large uncertainties and degeneracies. Over the years, UV to IR spectral energy distribution (SED) fitting utilizing varying approximations has revealed important results on the stellar and dust properties of galaxies. Yet the approximations limit the fidelity of the derived properties. There is sufficient computer power now available that it is now possible to remove these approximations and map out of landscape of galaxy SEDs using full dust radiative transfer. This improves upon previous work by directly connecting the UV, optical, and IR through dust grain physics. We present the DIRTYGrid, a grid of radiative transfer models of SEDs of dusty stellar populations in galactic environments designed to span the full range of physical parameters of galaxies. Using the stellar and gas radiation input from the stellar population synthesis model PEGASE, our radiative transfer model DIRTY self-consistently computes the UV to far-IR/sub-mm SEDs for each set of parameters in our grid. DIRTY computes the dust absorption, scattering, and emission from the local radiation field and a dust grain model, thereby physically connecting the UV-optical to the IR. We describe the computational method and explain the choices of parameters in DIRTYGrid. The computation took millions of CPU hours on supercomputers, and the SEDs produced are an invaluable tool for fitting multi-wavelength data sets. We provide the complete set of SEDs in an online table.

  3. Least-squares collocation meshless approach for radiative heat transfer in absorbing and scattering media

    NASA Astrophysics Data System (ADS)

    Liu, L. H.; Tan, J. Y.

    2007-02-01

    A least-squares collocation meshless method is employed for solving the radiative heat transfer in absorbing, emitting and scattering media. The least-squares collocation meshless method for radiative transfer is based on the discrete ordinates equation. A moving least-squares approximation is applied to construct the trial functions. Except for the collocation points which are used to construct the trial functions, a number of auxiliary points are also adopted to form the total residuals of the problem. The least-squares technique is used to obtain the solution of the problem by minimizing the summation of residuals of all collocation and auxiliary points. Three numerical examples are studied to illustrate the performance of this new solution method. The numerical results are compared with the other benchmark approximate solutions. By comparison, the results show that the least-squares collocation meshless method is efficient, accurate and stable, and can be used for solving the radiative heat transfer in absorbing, emitting and scattering media.

  4. The response of antioxidant systems in Nostoc sphaeroides against UV-B radiation and the protective effects of exogenous antioxidants

    NASA Astrophysics Data System (ADS)

    Wang, Gaohong; Hu, Chunxiang; Li, Dunhai; Zhang, Delu; Li, Xiaoyan; Chen, Kun; Liu, Yongding

    UV radiation is one of many harmful factors found in space that are detrimental to organisms on earth in space exploration. In the present work, we examined the role of antioxidant system in Nostoc sphaeroides Kütz (Cyanobacterium) and the effects of exogenously applied antioxidant molecules on its photosynthetic rate under UV-B radiation. It was found that UV-B radiation promoted the activity of antioxidant system to protect photosystem II (PSII) and exogenously applied antioxidant: sodium nitroprusside (SNP) and N-acetylcysteine (NAC) had an obvious protection on PSII activity under UV-B radiation. The activity of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7) and content of MDA (malondialdehyde) and ASC (ascorbate) were improved by 0.5 mM and 1 mM SNP, but 0.1 mM SNP decreased the activity of antioxidant system. Addition of exogenous NAC decreased the activity of SOD, POD, CAT and the content MDA and ASC. In contrast, exogenously applied NAC increased GSH content. The results suggest that exogenous SNP and NAC may protect algae by different mechanisms: SNP may play double roles as both sources of reactive free radicals as well as ROS scavengers in mediating the protective role of PSII on algae under UV-B radiation. On the other hand, NAC functions as an antioxidant or precursor of glutathione, which could protect PSII directly from UV-B radiation.

  5. The Effect of UV-B Radiation on Dissolved Organic Matter and Nitrogen Biogeochemistry in Aquatic Environments

    NASA Astrophysics Data System (ADS)

    Suddick, E. C.; Uher, G.; Woodward, M.; Upstill-Goddard, R. C.

    2006-12-01

    Peatlands are globally important reservoirs of carbon and represent important freshwater catchments in many regions. These waters generally contain high levels of dissolved organic matter (DOM), which contains a significant fraction of chromophoric, dissolved organic material (CDOM). CDOM is primarily responsible for light attenuation in these waters and affects a variety of biogeochemically relevant photo-processes including the formation of climatically active trace gases such as CO2, CO, COS and the release of essential plant micro-nutrients such as ammonium. Significant increases in DOM concentrations have been observed in various peatland waters over recent years, associated with increases in temperatures linked to global climate change. UV-B fluxes have also been projected to increase in the future as a consequence of stratospheric ozone depletion. Enhanced UV-B radiation can affect the balance between the biological processes that produce DOM and the chemical and microbial processes that degrade it. This infers that the rate of photochemical release of nutrients such as ammonium (photo-ammonification) is also likely to increase with increasing incident UV-B radiation. Samples of freshwater, riverine and marine, filtered (0.2 ìM) water were exposed to short-term natural and solar simulated irradiation which reduced their absorbance at 350 nm (a350) and total fluorescence intensity within the UV and visible regions and also produced changes in fluorescence excitation-emission matrix (EEM) measurements, such as the hypsochromic shift of peak A towards shorter wavelengths. Samples were taken from a variety of aqueous environments predominantly from Northern Scotland peatland freshwater catchments but also from the River Tyne, North East England and from the Iberian Coast, Atlantic Ocean, covering the a350 range 0.3 to 50 m-1. The photo-chemical release of ammonium from aquatic dissolved organic matter (DOM) was also concurrent with the photo-bleaching of DOM

  6. Detection of UV Pulse from Insulators and Application in Estimating the Conditions of Insulators

    NASA Astrophysics Data System (ADS)

    Wang, Jingang; Chong, Junlong; Yang, Jie

    2014-10-01

    Solar radiation in the band of 240-280 nm is absorbed by the ozone layer in the atmosphere, and corona discharges from high-voltage apparatus emit in air mainly in the 230-405 nm range of ultraviolet (UV), so the band of 240-280 nm is called UV Solar Blind Band. When the insulators in a string deteriorate or are contaminated, the voltage distribution along the string will change, which causes the electric fields in the vicinity of insulators change and corona discharge intensifies. An UV pulse detection method to check the conditions of insulators is presented based on detecting the UV pulse among the corona discharge, then it can be confirmed that whether there exist faulty insulators and whether the surface contamination of insulators is severe for the safe operation of power systems. An UV-I Insulator Detector has been developed, and both laboratory tests and field tests have been carried out which demonstrates the practical viability of UV-I Insulator Detector for online monitoring.

  7. The dominant allele Aft induces a shift from flavonol to anthocyanin production in response to UV-B radiation in tomato fruit.

    PubMed

    Catola, Stefano; Castagna, Antonella; Santin, Marco; Calvenzani, Valentina; Petroni, Katia; Mazzucato, Andrea; Ranieri, Annamaria

    2017-08-01

    The introgression of the A ft allele into domesticated tomato induced a shift from flavonol to anthocyanin production in response to UV-B radiation, while the hp - 1 allele negatively influenced the response of flavonoid biosynthesis to UV-B. Introgression of the dominant allele Anthocyanin fruit (Aft) from Solanum chilense induces anthocyanin accumulation in the peel of tomato (Solanum lycopersicum L.) fruit. UV-B radiation can influence plant secondary metabolism regulating the expression of several genes, among which those involved in flavonoid biosynthesis. Here, we investigated whether post-harvest UV-B treatment could up-regulate flavonoid production in tomato fruits and whether the Aft allele could affect flavonoid biosynthesis under UV-B radiation. Mature green fruits of an anthocyanin-rich tomato mutant line (SA206) and of its wild-type reference, cv. Roma, were daily subjected to post-harvest UV-B treatment until full ripening. Up-regulation of CHS and CHI transcription by UV-B treatment induced flavonoid accumulation in the peel of cv. Roma. Conversely, UV-B decreased the total flavonoid content and CHS transcript levels in the SA206 peel. SA206 being a double mutant containing also hp-1 allele, we investigated also the behavior of hp-1 fruit. The decreased peel flavonoid accumulation and gene transcription in response to UV-B suggest that hp-1 allele is involved in the marked down-regulation of the flavonoid biosynthesis observed in SA206 fruit. Interestingly, in SA206, UV-B radiation promoted the synthesis of delphinidin, petunidin, and malvidin by increasing F3'5'H and DFR transcription, but it decreased rutin production, suggesting a switch from flavonols to anthocyanins. Finally, although UV-B radiation does not reach the inner fruit tissues, it down-regulated flavonoid biosynthesis in the flesh of both genotypes. This study provides, for the first time, evidence that the presence of the functional Aft allele, under UV-B radiation, redirects

  8. Refractive Index Effects on Radiation in an Absorbing, Emitting, and Scattering Laminated Layer

    NASA Technical Reports Server (NTRS)

    Siegel, R.; Spuckler, C. M.

    1993-01-01

    A simple set of equations is derived for predicting temperature radiative energy flow in a two-region semitransparent laminated layer in the limit of zero heat conduction. The composite is heated on its two sides by unequal amounts of incident radiation. The two layers of the composite have different refractive indices, and each material absorbs, emits, and isotropically scatters radiation. The interfaces are diffuse, and all interface reflections are included. To illustrate the thermal behavior that is readily calculated from the equations, typical results an given for various optical thicknesses and refractive indices of the layers. Internal reflections have a substantial effect on the temperature distribution and radiative heat flow.

  9. Radiation heat transfer calculations for the uranium fuel-containment region of the nuclear light bulb engine.

    NASA Technical Reports Server (NTRS)

    Rodgers, R. J.; Latham, T. S.; Krascella, N. L.

    1971-01-01

    Calculation results are reviewed of the radiant heat transfer characteristics in the fuel and buffer gas regions of a nuclear light bulb engine based on the transfer of energy by thermal radiation from gaseous uranium fuel in a neon vortex, through an internally cooled transparent wall, to seeded hydrogen propellant. The results indicate that the fraction of UV energy incident on the transparent walls increases with increasing power level. For the reference engine power level of 4600 megw, it is necessary to employ space radiators to reject the UV radiated energy absorbed by the transparent walls. This UV energy can be blocked by employing nitric oxide and oxygen seed gases in the fuel and buffer gas regions. However, this results in increased UV absorption in the buffer gas which also requires space radiators to reject the heat load.

  10. UV Radiation in an Urban Canyon in Southeast Queensland

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  11. Radical protection by differently composed creams in the UV/VIS and IR spectral ranges.

    PubMed

    Meinke, Martina C; Syring, Felicia; Schanzer, Sabine; Haag, Stefan F; Graf, Rüdiger; Loch, Manuela; Gersonde, Ingo; Groth, Norbert; Pflücker, Frank; Lademann, Jürgen

    2013-01-01

    Modern sunscreens are well suited to provide sufficient protection in the UV range because the filter substances absorb or scatter UV radiation. Although up to 50% of radicals are formed in the visible and infrared spectral range during solar radiation protection strategies are not provided in this range. Previous investigations of commercially available products have shown that in addition to physical filters, antioxidants (AO) are necessary to provide protective effects in the infrared range by neutralizing already formed radicals. In this study, the efficacy of filter substances and AO to reduce radical formation in both spectral ranges was investigated after UV/VIS or IR irradiation. Optical properties and radical protection were determined for the investigated creams. It was found that organic UV filters lower radical formation in the UV/VIS range to 35% compared to untreated skin, independent of the presence of AO. Further reduction to 14% was reached by addition of 2% physical filters, whereas physical filters alone were ineffective in the UV/VIS range due to the low concentration. In contrast, this filter type reduced radical formation in the IR range significantly to 65%; similar effects were aroused after application of AO. Sunscreens which contain organic UV filters, physical filters and AO ensure protection in the complete solar spectrum. © 2013 The American Society of Photobiology.

  12. Observations of the diffuse near-UV radiation field

    NASA Technical Reports Server (NTRS)

    Murthy, J.; Henry, R. C.; Feldman, P. D.; Tennyson, P. D.

    1990-01-01

    The diffuse radiation field from 1650-3100 A has been observed by spectrometer aboard the Space Shuttle, and the contributions of the zodiacal light an the diffuse cosmic background to the signal have been derived. Colors ranging from 0.65 to 1.2 are found for the zodiacal light with an almost linear increase in the color with ecliptic latitude. This rise in color is due to UV brightness remaining almost constant while the visible brightnesses drop by almost a factor of two. This is interpreted as evidence that the grains responsible for the UV scattering have much more uniform distribution with distance from the ecliptic plane than do those grains responsible for the visible scattering. Intensities for the cosmic diffuse background ranging from 300 units to 900 units are found which are not consistent with either a correlation with N(H I) or with spatial isotropy.

  13. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of the- art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments. This approach can lead to large loss of water and a significant mass penalty for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. The optimal system is based on a trade-off between the mass of water saved and extra power needed to regenerate the LiCl absorber. This paper describes analysis models and the predicted performance and optimize the size of the SEAR system, estimated size and mass of key components, and power requirements for regeneration. We also present a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  14. Simultaneous Solid Phase Extraction and Derivatization of Aliphatic Primary Amines Prior to Separation and UV-Absorbance Detection

    PubMed Central

    Felhofer, Jessica L.; Scida, Karen; Penick, Mark; Willis, Peter A.; Garcia, Carlos D.

    2013-01-01

    To overcome the problem of poor sensitivity of capillary electrophoresis-UV absorbance for the detection of aliphatic amines, a solid phase extraction and derivatization scheme was developed. This work demonstrates successful coupling of amines to a chromophore immobilized on a solid phase and subsequent cleavage and analysis. Although the analysis of many types of amines is relevant for myriad applications, this paper focuses on the derivatization and separation of amines with environmental relevance. This work aims to provide the foundations for future developments of an integrated sample preparation microreactor capable of performing simultaneous derivatization, preconcentration, and sample cleanup for sensitive analysis of primary amines. PMID:24054648

  15. Can dual chlorophyll fluorescence excitation be used to assess the variation in the content of UV-absorbing phenolic compounds in leaves of temperate tree species along a light gradient?

    PubMed

    Barthod, Sandrine; Cerovic, Zoran; Epron, Daniel

    2007-01-01

    The present study assesses light-induced variations in phenolic compounds in leaves of saplings of two co-occurring temperate species (Acer platanoides L., and Fraxinus excelsior L.) along a light gradient using a new non-invasive optical method (Dualex). The Dualex-derived UV absorbance of leaf epidermis (the sum of the adaxial and abaxial faces, AUV) increased significantly with increasing light in both species. AUV values were correlated with absorbance of the leaf extract at 305 nm and 375 nm (A305 and A375) in both species with similar slopes for both species. However, a large difference in intercept was observed between the two species when A305 was regressed against AUV. Similarly, AUV values were well correlated with the amount of phenolics in the leaf extracts assessed by the Folin-Ciocalteu method, but slopes were significantly different for the two species. Thus, the UV-A epidermal transmittance, despite being a reliable indicator of the UV-screening capacity of the leaf epidermis, cannot be used for any quantitative estimate of UV-B screening capacity or of energetic requirement for leaf construction without a species-specific calibration.

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

    PubMed

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

    2015-08-01

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

  17. Refuge quality to cope with UV radiation affects energy allocation in an intertidal fish.

    PubMed

    Vargas, Juan; Duarte, Cristian; Galban-Malagón, Cristóbal; Roberto García-Huidobro, M; Aldana, Marcela; Pulgar, José

    2018-05-01

    Ultraviolet (UV) radiation is a primary environmental stressor for marine species inhabiting intertidal pools. Thus, the use of microhabitats as refuges is key to protect organisms against this stressor. In this study, we compared the quality of rocky and algae as refuges for the intertidal fish Girella laevifrons exposed to UV radiation. Refuge quality was studied by evaluating oxygen consumption and weight gain in control and UV-exposed fish. Rocky-refuge fish consumed less oxygen and gained significantly more weight than algal-refuge fish. The obtained results support the importance of refuge quality on energetic balance of intertidal organisms, where energy can be differentially allocated towards key life processes such as protection/repair or growth. Energy trade-offs need to be considered in research concerning animals inhabiting stressful habitats. Copyright © 2018. Published by Elsevier Ltd.

  18. Refractive Index and Absorption Attribution of Highly Absorbing Brown Carbon Aerosols from an Urban Indian City-Kanpur.

    PubMed

    Shamjad, P M; Tripathi, S N; Thamban, Navaneeth M; Vreeland, Heidi

    2016-11-24

    Atmospheric aerosols influence Earth's radiative balance, having both warming and cooling effects. Though many aerosols reflect radiation, carbonaceous aerosols such as black carbon and certain organic carbon species known as brown carbon have the potential to warm the atmosphere by absorbing light. Black carbon absorbs light over the entire solar spectrum whereas brown carbon absorbs near-UV wavelengths and, to a lesser extent, visible light. In developing countries, such as India, where combustion sources are prolific, the influence of brown carbon on absorption may be significant. In order to better characterize brown carbon, we present experimental and modeled absorption properties of submicron aerosols measured in an urban Indian city (Kanpur). Brown carbon here is found to be fivefold more absorbing at 365 nm wavelength compared to previous studies. Results suggest ~30% of total absorption in Kanpur is attributed to brown carbon, with primary organic aerosols contributing more than secondary organics. We report the spectral brown carbon refractive indices along with an experimentally constrained estimate of the influence of aerosol mixing state on absorption. We conclude that brown carbon in Kanpur is highly absorbing in nature and that the mixing state plays an important role in light absorption from volatile species.

  19. Refractive Index and Absorption Attribution of Highly Absorbing Brown Carbon Aerosols from an Urban Indian City-Kanpur

    PubMed Central

    Shamjad, P. M.; Tripathi, S. N.; Thamban, Navaneeth M.; Vreeland, Heidi

    2016-01-01

    Atmospheric aerosols influence Earth’s radiative balance, having both warming and cooling effects. Though many aerosols reflect radiation, carbonaceous aerosols such as black carbon and certain organic carbon species known as brown carbon have the potential to warm the atmosphere by absorbing light. Black carbon absorbs light over the entire solar spectrum whereas brown carbon absorbs near-UV wavelengths and, to a lesser extent, visible light. In developing countries, such as India, where combustion sources are prolific, the influence of brown carbon on absorption may be significant. In order to better characterize brown carbon, we present experimental and modeled absorption properties of submicron aerosols measured in an urban Indian city (Kanpur). Brown carbon here is found to be fivefold more absorbing at 365 nm wavelength compared to previous studies. Results suggest ~30% of total absorption in Kanpur is attributed to brown carbon, with primary organic aerosols contributing more than secondary organics. We report the spectral brown carbon refractive indices along with an experimentally constrained estimate of the influence of aerosol mixing state on absorption. We conclude that brown carbon in Kanpur is highly absorbing in nature and that the mixing state plays an important role in light absorption from volatile species. PMID:27883083

  20. Response and Defense Mechanisms of Taxus chinensis Leaves Under UV-A Radiation are Revealed Using Comparative Proteomics and Metabolomics Analyses.

    PubMed

    Zheng, Wen; Komatsu, Setsuko; Zhu, Wei; Zhang, Lin; Li, Ximin; Cui, Lei; Tian, Jingkui

    2016-09-01

    Taxus chinensis var. mairei is a species endemic to south-eastern China and one of the natural sources for the anticancer medicine paclitaxel. To investigate the molecular response and defense mechanisms of T. chinensis leaves to enhanced ultraviolet-A (UV-A) radiation, gel-free/label-free and gel-based proteomics and gas chromatography-mass spectrometry (GC-MS) analyses were performed. The transmission electron microscopy results indicated damage to the chloroplast under UV-A radiation. Proteomics analyses in leaves and chloroplasts showed that photosynthesis-, glycolysis-, secondary metabolism-, stress-, and protein synthesis-, degradation- and activation-related systems were mainly changed under UV-A radiation. Forty-seven PSII proteins and six PSI proteins were identified as being changed in leaves and chloroplasts under UV-A treatment. This indicated that PSII was more sensitive to UV-A than PSI as the target of UV-A light. Enhanced glycolysis, with four glycolysis-related key enzymes increased, provided precursors for secondary metabolism. The 1-deoxy-d-xylulose-5-phosphate reductoisomerase and 4-hydroxy-3-methylbut-2-enyl diphosphate reductase were identified as being significantly increased during UV-A radiation, which resulted in paclitaxel enhancement. Additionally, mRNA expression levels of genes involved in the paclitaxel biosynthetic pathway indicated a down-regulation under UV-A irradiation and up-regulation in dark incubation. These results reveal that a short-term high dose of UV-A radiation could stimulate the plant stress defense system and paclitaxel production. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Kinetics of UV laser radiation defects in high performance glasses

    NASA Astrophysics Data System (ADS)

    Natura, U.; Feurer, T.; Ehrt, D.

    2000-05-01

    High purity fluoride phosphate glasses are attractive candidates as UV transmitting materials. The calculated values for the ultraviolet resonance wavelength are comparable with those of pure silica glass or fluoride single crystal CaF2. The formation of radiation-induced defect centers leads to additional absorption bands in the VUV-UV-vis range. The damage and the healing behavior by lamps and lasers are investigated in dependence on phosphate content and the content of impurities, mainly transition metals. Experiments were carried out using pulsed lasers with a duration of femto- and nanoseconds at a wavelength of 248 nm. The initial slope of the induced absorption shows a nonlinear dependence on the pulse energy density. Resonant and non-resonant two-photon mechanisms were observed. Two-photon-absorption coefficients at 248 nm for samples with different phosphate contents were measured. Models of the kinetics of the radiation-induced defects were developed. The inclusion of energy transfer was necessary to explain the difference in the damage behavior for nanosecond (248 nm, 193 nm) and femtosecond (248 nm) laser pulses.

  2. [Effect of ultraviolet radiation on ALDH1 expression in human lens epithelial cells].

    PubMed

    Shi, Jingming; Jia, Songbai; Chen, Xuan; Tang, Luosheng

    2012-06-01

    To determine the apoptosis-inducing effect of ultraviolet light (UV) on human lens epithelial cell (HLEC) and to explore the involvement of changes in ALDH1 folowing UV radiation. HLEC was exposed to the same UV light source and was subsequently divided into 6 groups according to UV radiation time of 0 (control group), 5, 10, 15, and 30 min. Apoptosis was detected by AO/EB staining. Changes of ALDH1 in HLEC were detected by immunohistochemical staining and Western blot. The intensity of immunohistochemical staining and the rate of positive cells decreased with increase of UV time (P<0.05). The rate of positive ALDH1 cells was negatively correlated with the rate of apoptosis (r= -0.92, P<0.05). Western blot showed the integrated absorbance values significantly decreased with the increase of UV time (P<0.05). ALDH1 in HLEC decreases with an increase of UV exposure, which may be related to UV induced apoptosis of HLEC.

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  5. Sensitivity of multiangle photo-polarimetry to absorbing aerosol vertical layering and properties: Quantifying measurement uncertainties for ACE requirements

    NASA Astrophysics Data System (ADS)

    Kalashnikova, O. V.; Garay, M. J.; Davis, A. B.; Natraj, V.; Diner, D. J.; Tanelli, S.; Martonchik, J. V.; JPl Team

    2011-12-01

    The impact of tropospheric aerosols on climate can vary greatly based upon relatively small variations in aerosol properties, such as composition, shape and size distributions, as well as vertical layering. Multi-angle polarimetric measurements have been advocated in recent years as an additional tool to better understand and retrieve the aerosol properties needed for improved predictions of aerosol radiative forcing on climate. The central concern of this work is the assessment of the effects of absorbing aerosol properties under measurement uncertainties achievable for future generation multi-angle, polarimetric imaging instruments under ACE mission requirements. As guidelines, the on-orbit performance of MISR for multi-angle intensity measurements and the reported polarization sensitivities of a MSPI prototype were adopted. In particular, we will focus on sensitivities to absorbing aerosol layering and observation-constrained refractive indices (resulting in various single scattering albedos (SSA)) of both spherical and non-spherical absorbing aerosol types. We conducted modeling experiments to determine how the measured Stokes vector elements are affected in UV-NIR range by the vertical distribution, mixing and layering of smoke and dust aerosols, and aerosol SSA under the assumption of a black and polarizing ocean surfaces. We use a vector successive-orders-of-scattering (SOS) and VLIDORT transfer codes that show excellent agreement. Based on our sensitivity studies we will demonstrate advantages and disadvantages of wavelength selection in UV-NIR range to access absorbing aerosol properties. Polarized UV channels do not show particular advantage for absorbing aerosol property characterization due to dominating molecular signal. Polarimetric SSA sensitivity is small, however needed to be considered in the future polarimetric retrievals under ACE-defined uncertainty.

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

    Treesearch

    Gordon M. Heisler

    2010-01-01

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

  7. Nanosecond laser-induced back side wet etching of fused silica with a copper-based absorber liquid

    NASA Astrophysics Data System (ADS)

    Lorenz, Pierre; Zehnder, Sarah; Ehrhardt, Martin; Frost, Frank; Zimmer, Klaus; Schwaller, Patrick

    2014-03-01

    Cost-efficient machining of dielectric surfaces with high-precision and low-roughness for industrial applications is still challenging if using laser-patterning processes. Laser induced back side wet etching (LIBWE) using UV laser pulses with liquid heavy metals or aromatic hydrocarbons as absorber allows the fabrication of well-defined, nm precise, free-form surfaces with low surface roughness, e.g., needed for optical applications. The copper-sulphatebased absorber CuSO4/K-Na-Tartrate/NaOH/formaldehyde in water is used for laser-induced deposition of copper. If this absorber can also be used as precursor for laser-induced ablation, promising industrial applications combining surface structuring and deposition within the same setup could be possible. The etching results applying a KrF excimer (248 nm, 25 ns) and a Nd:YAG (1064 nm, 20 ns) laser are compared. The topography of the etched surfaces were analyzed by scanning electron microscopy (SEM), white light interferometry (WLI) as well as laser scanning microscopy (LSM). The chemical composition of the irradiated surface was studied by energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT-IR). For the discussion of the etching mechanism the laser-induced heating was simulated with finite element method (FEM). The results indicate that the UV and IR radiation allows micro structuring of fused silica with the copper-based absorber where the etching process can be explained by the laser-induced formation of a copper-based absorber layer.

  8. A novel catalytic ceramic membrane fabricated with CuMn2O4 particles for emerging UV absorbers degradation from aqueous and membrane fouling elimination.

    PubMed

    Guo, Yang; Song, Zilong; Xu, Bingbing; Li, Yanning; Qi, Fei; Croue, Jean-Philippe; Yuan, Donghai

    2018-02-15

    A novel catalytic ceramic membrane (CM) for improving ozonation and filtration performance was fabricated by surface coating CuMn 2 O 4 particles on a tubular CM. The degradation of ultraviolet (UV) absorbers, reduction of toxicity, elimination of membrane fouling and catalytic mechanism were investigated. The characterization results suggested the particles were well-fixed on membrane surface. The modified membrane showed improved benzophenone-3 removal performance (from 28% to 34%), detoxification (EC 50 as 12.77%) and the stability of catalytic activity. In the degradation performance of model UV absorbers, the developed membrane significantly decreased the UV254 and DOC values in effluent. Compared with a virgin CM, this CM ozonation increased water flux as 29.9% by in-situ degrade effluent organic matters. The CuMn 2 O 4 modified membrane enhanced the ozone self-decompose to generate O 2 - and initiated the chain reaction of ozone decomposition, and subsequently reacted with molecule ozone to produce OH. Additionally, CM was able to promote the interaction between ozone and catalyst/organic chemicals to form H 2 O 2 that promoted the formation of OH. This catalytic ceramic membrane combining with ozonation showed potential applications in emerging pollutant degradation and membrane fouling elimination, and acted as a novel ternary technology for wastewater treatment and water reuse. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Radiation force on absorbing targets and power measurements of a high intensity focused ultrasound (HIFU) source

    NASA Astrophysics Data System (ADS)

    Qian, Zuwen; Zhu, Zhemin; Ye, Shigong; Jiang, Wenhua; Zhu, Houqing; Yu, Jinshen

    2010-10-01

    Based on the analytic expressions for the radiated field of a circular concave piston given by Hasegawa et al., an integral for calculation of the radiation force on a plane absorbing target in a spherically focused field is derived. A general relation between acoustic power P and normal radiation force F n is obtained under the condition of kr ≫ 1. Numerical computation is carried out by using the symbolic computation program for practically focused sources and absorbing circular targets. The results show that, for a given source, there is a range of target positions where the radiation force is independent of the target’s position under the assumption that the contribution of the acoustic field behind the target to the radiation force can be neglected. The experiments are carried out and confirm that there is a range of target positions where the measured radiation force is basically independent of the target’s position even at high acoustic power (up to 700 W). It is believed that when the radiation force method is used to measure the acoustic power radiated from a focused source, the size of the target must be selected in such a way that no observable sound can be found in the region behind the target.

  10. Photocurable acrylic composition, and U.V. curing with development of U.V. absorber

    DOEpatents

    McKoy, Vincent B.; Gupta, Amitava

    1992-01-01

    In-situ development of an ultraviolet absorber is provided by a compound such as a hydroxy-phenyl-triazole containing a group which protects the absorber during actinically activated polymerization by light at first frequency. After polymerization the protective group is removed by actinic reaction at a second frequency lower than the first frequency. The protective group is formed by replacing the hydrogen of the hydroxyl group with an acyl group containing 1 to 3 carbon atoms or an acryloxy group of the formula: ##STR1## where R.sup.1 is either an alkyl containing 1 to 6 carbon atoms or --CH.dbd.CH.sub.2.

  11. UV exposure in cars.

    PubMed

    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.

  12. Aureole radiance field about a source in a scattering-absorbing medium.

    PubMed

    Zachor, A S

    1978-06-15

    A technique is described for computing the aureole radiance field about a point source in a medium that absorbs and scatters according to an arbitrary phase function. When applied to an isotropic source in a homogenous medium, the method uses a double-integral transform which is evaluated recursively to obtain the aureole radiances contributed by successive scattering orders, as in the Neumann solution of the radiative transfer equation. The normalized total radiance field distribution and the variation of flux with field of view and range are given for three wavelengths in the uv and one in the visible, for a sea-level model atmosphere assumed to scatter according to a composite of the Rayleigh and modified Henyey-Greenstein phase functions. These results have application to the detection and measurement of uncollimated uv and visible sources at short ranges in the lower atmosphere.

  13. Recent studies on UV radiation in Brazil

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  14. Influence of UV radiation and nitrosamines on the induction of mycotoxins synthesis by nontoxigenic moulds isolated from feed samples.

    PubMed

    Aziz, Nagy H; Smyk, B

    2002-04-01

    The effects of UV radiation and nitrosamines on the induction of mycotoxin biosynthesis by some nontoxigenic moulds isolated from feed samples collected from Egypt and Poland was investigated. Nontoxigenic strains of Aspergillus flavus P-63, A. niger EN-200 and A. ochraceus P-157 synthesized mycotoxins (aflatoxins and ochratoxin, A) after exposure to near UV radiation for 120-210 min. Nitrosamines (DMNA and DENA) at 30 up to 1000 ppm induced the synthesis of aflatoxins by nontoxigenic species of A. flavus ES-255 and P-63 and A. niger EN 200. Near-UV radiation and nitrosamines had no influence on the induction of mycotoxin synthesis by Penicillium and Fusarium isolates. All nontoxigenic strains of Aspergilli which synthesized aflatoxins in the presence of 1000 ppm nitrosamines, also synthesized continuously aflatoxins during the next fifteen generations. Near-UV radiation and nitrosamines had a mutagenic effect on the induction of mycotoxins synthesis by nontoxigenic moulds.

  15. Survival of Staphylococcus aureus exposed to UV radiation on the surface of ceramic tiles coated with TiO2.

    PubMed

    Szczawiński, J; Tomaszewski, H; Jackowska-Tracz, A; Szczawińska, M E

    2011-01-01

    The aim of this study was to determine and compare the antimicrobial activity of UV radiation of wavelength 253.7 nm (used in typical germicidal lamps) against Staphylococcus aureus on the surfaces of conventionally produced white ceramic wall tiles (matt and shiny) and the same tiles coated with TiO2 using three different methods: RF diode sputtering, atmospheric pressure chemical vapour deposition (APCVD) and spray pyrolysis deposition (SPD). Results clearly indicate that the bactericidal action of UV radiation is much stronger on the surfaces of tiles coated with TiO2 than on the tiles uncovered. The strongest bactericidal effect of UV radiation was found for film prepared by APCVD. Results of experiments for shiny and matt tiles did not differ statistically. The use of ceramic wall tiles coated with TiO2 films in hospitals, veterinary clinics, laboratories, food processing plants and other places where UV radiation is applied for disinfection should greatly improve the efficiency of this treatment.

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

    PubMed

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

    2015-05-01

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

  17. Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2013-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  18. Can UV radiation-blocking soft contact lenses attenuate UV radiation to safe levels during summer months in the southern United States?

    PubMed

    Walsh, James E; Bergmanson, Jan P G; Saldana, Gerardo; Gaume, Amber

    2003-01-01

    Peak solar UV radiation (UVR) intensities are typically experienced in summer months. People living in the southern states of the United States, where the UVR frequently exceeds the recommended minimum erythema dose (MED), are at particular risk, especially outdoor workers. The present study analyzed summertime MED readings in Houston, TX, to assess the frequency of intensities regarded as unhealthy. The study also sought to assess whether UV-blocking hydrogel contact lenses provide ocular protection from these high doses. Readings, taken at midday using a UVR biometer, were analyzed to assess the potential UVR risk. The spectral response of the meter, modified by the spectral transmission curves of the contact lenses, allowed us to mathematically assess the ocular protection provided. In addition, ambient UVR measurements were taken at midday, using a portable UVR radiometer. The detector was adapted so that a standard diameter hydrogel contact lens could be placed over it to quantify the UV-blocking capabilities of the lens. The MED readings showed that the recommended safety standards were exceeded approximately at local midday 90% of the time. Model calculations and empirical data demonstrated that contact lenses attenuated the MED readings by up to 90%, bringing them well within the recommended Environmental Protection Agency safety standards. The efficacy of the model used in this study was verified through direct comparison of the modeled and measured data. UV-blocking hydrogel soft contact lenses reduce the MED to the human eye and therefore limit the lifetime ocular dose. These lenses are highly recommended to prevent the development of UVR-related ocular pathologic conditions.

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

    PubMed

    Ishay, Jacob S; Pertsis, Vitaly

    2002-01-01

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

  20. The Methoxyflavonoid Isosakuranetin Suppresses UV-B-Induced Matrix Metalloproteinase-1 Expression and Collagen Degradation Relevant for Skin Photoaging.

    PubMed

    Jung, Hana; Lee, Eunjoo H; Lee, Tae Hoon; Cho, Man-Ho

    2016-09-01

    Solar ultraviolet (UV) radiation is a main extrinsic factor for skin aging. Chronic exposure of the skin to UV radiation causes the induction of matrix metalloproteinases (MMPs), such as MMP-1, and consequently results in alterations of the extracellular matrix (ECM) and skin photoaging. Flavonoids are considered as potent anti-photoaging agents due to their UV-absorbing and antioxidant properties and inhibitory activity against UV-mediated MMP induction. To identify anti-photoaging agents, in the present study we examined the preventative effect of methoxyflavonoids, such as sakuranetin, isosakuranetin, homoeriodictyol, genkwanin, chrysoeriol and syringetin, on UV-B-induced skin photo-damage. Of the examined methoxyflavonoids, pretreatment with isosakuranetin strongly suppressed the UV-B-mediated induction of MMP-1 in human keratinocytes in a concentration-dependent manner. Isosakuranetin inhibited UV-B-induced phosphorylation of mitogen-activated protein kinase (MAPK) signaling components, ERK1/2, JNK1/2 and p38 proteins. This result suggests that the ERK1/2 kinase pathways likely contribute to the inhibitory effects of isosakuranetin on UV-induced MMP-1 production in human keratinocytes. Isosakuranetin also prevented UV-B-induced degradation of type-1 collagen in human dermal fibroblast cells. Taken together, our findings suggest that isosakuranetin has the potential for development as a protective agent for skin photoaging through the inhibition of UV-induced MMP-1 production and collagen degradation.

  1. Ultraviolet radiation-induced suppression of contact hypersensitivity in relation to padimate O and oxybenzone.

    PubMed

    Fisher, M S; Menter, J M; Willis, I

    1989-03-01

    Contact hypersensitivity (CHS) in mice can be induced by cutaneous sensitization followed by elicitation via ear-painting with trinitrochlorobenzene (TNCB). This CHS reaction is systemic and can be suppressed by exposure of mice to suberythemogenic doses of 280-315 nm radiation. In this study, we investigated whether a commercially available water-resistant sunscreen, either SPF-6 or SPF-15, containing Padimate O (UVB absorber) and oxybenzone (UVA absorber), was effective in preventing systemic suppression of CHS induced by either FS36 sunlamp exposure or solar simulating radiation. We observed that these two sunscreen preparations were totally incapable of preventing the immunologic suppression of contact hypersensitivity by UV radiation. These results indicate that application of sunscreen does not retard the development of suppression of CHS following repeated UV exposure under conditions where erythema is not clinically observed. Thus, erythema may not be a good end point for assessing systemic immune suppression and its consequences.

  2. Highlights from 40 Years of Satellite UV Measurements

    NASA Technical Reports Server (NTRS)

    Bhartia, Pawan K.

    2010-01-01

    This year we are celebrating the 40th anniversary of the launch of the Backscatter Ultraviolet (BUV) instrument on NASA's Nimbus-4 satellite. The purpose of this instrument was to demonstrate the capability to measure total column ozone and its vertical distribution from space. The success of this instrument led to about a dozen instruments of this type on various NASA and NOAA satellites. These instruments used a single photomultiplier tube (PMT) that restricted the measurements to 6-12 discrete wavelengths in the 250-380 nm range. With the availability of solid-state detector arrays in the past decade it has been possible to make similar measurements but with hyperspectral (contiguous in wavelength) sampling and enhanced spectral resolution. This has allowed global mapping of several weakly-absorbing trace gases including S0 2, NO2, BrO, HCHO, and CIIOCHO. Since these measurements are affected by clouds and aerosols, a great deal of effort has gone into understanding their effect on ultraviolet radiation- both upwelling and downwelling. The downwelling UV radiation is chemically and biologically active and has both negative (genetic damage, air pollution) and positive (production of vitamin D and OH radical) environmental effects. I will discuss how the interaction of Rayleigh-scattered UV radiation with clouds and aerosols produce a variety of interesting effects that are leading to new methods of remote sensing of their properties. The UV measurements can greatly enhance the information that one derives from more traditional methods that use infrared and visible part of the solar spectrum.

  3. Atmospheric scattering of middle uv radiation from an internal source.

    PubMed

    Meier, R R; Lee, J S; Anderson, D E

    1978-10-15

    A Monte Carlo model has been developed which simulates the multiple-scattering of middle-uv radiation in the lower atmosphere. The source of radiation is assumed to be monochromatic and located at a point. The physical effects taken into account in the model are Rayleigh and Mie scattering, pure absorption by particulates and trace atmospheric gases, and ground albedo. The model output consists of the multiply scattered radiance as a function of look-angle of a detector located within the atmosphere. Several examples are discussed, and comparisons are made with direct-source and single-scattered contributions to the signal received by the detector.

  4. UV-Induced cell death in plants.

    PubMed

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

    2013-01-14

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

  5. Warm Absorber Diagnostics of AGN Dynamics

    NASA Astrophysics Data System (ADS)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  6. Quantitation of underivatized branched-chain amino acids in sport nutritional supplements by capillary electrophoresis with direct or indirect UV absorbance detection.

    PubMed

    Qiu, Jun; Wang, Jinhao; Xu, Zhongqi; Liu, Huiqing; Ren, Jie

    2017-01-01

    The branched-chain amino acids (BCAAs) including leucine (Leu), isoleucine (Ile) and valine (Val) play a pivotal role in the human body. Herein, we developed capillary electrophoresis (CE) coupled with conventional UV detector to quantify underivatized BCAAs in two kinds of sport nutritional supplements. For direct UV detection at 195 nm, the BCAAs (Leu, two enantiomers of Ile and Val) were separated in a background electrolyte (BGE) consisting of 40.0 mmol/L sodium tetraborate, and 40.0 mmol/L β-cyclodextrin (β-CD) at pH 10.2. In addition, the indirect UV detection at 264 nm was achieved in a BGE of 2.0 mmol/L Na2HPO4, 10.0 mmol/L p-aminosalicylic acid (PAS) as UV absorbing probe, and 40.0 mmol/L β-CD at pH 12.2. The β-CD significantly benefited the isomeric separation of Leu, L- and D-Ile. The optimal conditions allowed the LODs (limit of detections) of direct and indirect UV absorption detection to be tens μmol/L level, which was comparable to the reported CE inline derivatization method. The RSDs (relative standard deviations) of migration time and peak area were less than 0.91% and 3.66% (n = 6). Finally, CE with indirect UV detection method was applied for the quantitation of BCAAs in two commercial sport nutritional supplements, and good recovery and precision were obtained. Such simple CE method without tedious derivatization process is feasible of quality control and efficacy evaluation of the supplemental proteins.

  7. Quantitation of underivatized branched-chain amino acids in sport nutritional supplements by capillary electrophoresis with direct or indirect UV absorbance detection

    PubMed Central

    Liu, Huiqing; Ren, Jie

    2017-01-01

    The branched-chain amino acids (BCAAs) including leucine (Leu), isoleucine (Ile) and valine (Val) play a pivotal role in the human body. Herein, we developed capillary electrophoresis (CE) coupled with conventional UV detector to quantify underivatized BCAAs in two kinds of sport nutritional supplements. For direct UV detection at 195 nm, the BCAAs (Leu, two enantiomers of Ile and Val) were separated in a background electrolyte (BGE) consisting of 40.0 mmol/L sodium tetraborate, and 40.0 mmol/L β-cyclodextrin (β-CD) at pH 10.2. In addition, the indirect UV detection at 264 nm was achieved in a BGE of 2.0 mmol/L Na2HPO4, 10.0 mmol/L p-aminosalicylic acid (PAS) as UV absorbing probe, and 40.0 mmol/L β-CD at pH 12.2. The β-CD significantly benefited the isomeric separation of Leu, L- and D-Ile. The optimal conditions allowed the LODs (limit of detections) of direct and indirect UV absorption detection to be tens μmol/L level, which was comparable to the reported CE inline derivatization method. The RSDs (relative standard deviations) of migration time and peak area were less than 0.91% and 3.66% (n = 6). Finally, CE with indirect UV detection method was applied for the quantitation of BCAAs in two commercial sport nutritional supplements, and good recovery and precision were obtained. Such simple CE method without tedious derivatization process is feasible of quality control and efficacy evaluation of the supplemental proteins. PMID:28640882

  8. The UVR8 UV-B Photoreceptor: Perception, Signaling and Response

    PubMed Central

    Tilbrook, Kimberley; Arongaus, Adriana B.; Binkert, Melanie; Heijde, Marc; Yin, Ruohe; Ulm, Roman

    2013-01-01

    Ultraviolet-B radiation (UV-B) is an intrinsic part of sunlight that is accompanied by significant biological effects. Plants are able to perceive UV-B using the UV-B photoreceptor UVR8 which is linked to a specific molecular signaling pathway and leads to UV-B acclimation. Herein we review the biological process in plants from initial UV-B perception and signal transduction through to the known UV-B responses that promote survival in sunlight. The UVR8 UV-B photoreceptor exists as a homodimer that instantly monomerises upon UV-B absorption via specific intrinsic tryptophans which act as UV-B chromophores. The UVR8 monomer interacts with COP1, an E3 ubiquitin ligase, initiating a molecular signaling pathway that leads to gene expression changes. This signaling output leads to UVR8-dependent responses including UV-B-induced photomorphogenesis and the accumulation of UV-B-absorbing flavonols. Negative feedback regulation of the pathway is provided by the WD40-repeat proteins RUP1 and RUP2, which facilitate UVR8 redimerization, disrupting the UVR8-COP1 interaction. Despite rapid advancements in the field of recent years, further components of UVR8 UV-B signaling are constantly emerging, and the precise interplay of these and the established players UVR8, COP1, RUP1, RUP2 and HY5 needs to be defined. UVR8 UV-B signaling represents our further understanding of how plants are able to sense their light environment and adjust their growth accordingly. PMID:23864838

  9. [Knowledge about UV-radiation and sun protection: survey of adolescents and young adults in Bavaria].

    PubMed

    Eichhorn, C; Seibold, C; Loss, J; Steinmann, A; Nagel, E

    2008-10-01

    Identifying deficits in sun protection knowledge and behavior can serve as a starting point for primary prevention interventions. The aim of this study was to investigate knowledge and behavior related to ultraviolet radiation in the population between 14 and 45 years of age in Bavaria, as well as effects of the awareness campaign "Sensible in the Sun". In two Bavarian districts, 545 individuals of the target population completed a telephone survey about risks of UV-radiation, sun protection knowledge and behavior, and effects of the campaign. Sunburn and skin cancer as adverse effects of ultraviolet radiation were named by almost every participant. When asked about protective interventions, 91% mentioned sunscreen and 45-54% clothing, limited stay in the sun and seeking shade at noon. Women were better informed than men, adults better than adolescents. 10.6% were aware of the campaign. In this group, 37.9% had been motivated to consider their sun protective behavior; 13.8% (especially women >30 years) stated they had changed their behavior because of the campaign. There were deficits in knowledge, especially about eye damage and the importance of getting slowly used to UV radiation. Physician advice, but also broadcast and print media, has an effect on UV-related knowledge.

  10. The effects of UV-B radiation intensity on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum.

    PubMed

    Yao, Xiao-Qin; Chu, Jian-Zhou; He, Xue-Li; Si, Chao

    2014-01-01

    The article studied UV-B effects on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum during the bud stage. The experiment included four UV-B radiation levels (CK, ambient UV-B; T1, T2 and T3 indicated a 5%, 10% and 15% increase in ambient UV-BBE, respectively) to determine the optimal UV-B radiation intensity in regulating active ingredients level in flowers of two chrysanthemum varieties. Flower dry weight of two cultivars was not affected by UV-B radiation under experimental conditions reported here. UV-B treatments significantly increased the rate of superoxide radical production, hydrogen peroxide (H2O2) (except for T1) and malondialdehyde concentration in flowers of Huai chrysanthemum and H2O2 concentration in flowers of Qi chrysanthemum. T2 and T3 treatments induced a significant increase in phenylalanine ammonia lyase enzyme (PAL) activity, anthocyanins, proline, ascorbic acid, chlorogenic acid and flavone content in flowers of two chrysanthemum varieties, and there were no significant differences in PAL activity, ascorbic acid, flavone and chlorogenic acid content between the two treatments. These results indicated that appropriate UV-B radiation intensity did not result in the decrease in flower yield, and could regulate PAL activity and increase active ingredients content in flowers of two chrysanthemum varieties. © 2014 The American Society of Photobiology.

  11. UV-Induced Cell Death in Plants

    PubMed Central

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

    2013-01-01

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

  12. The effects of UV radiation A and B on diurnal variation in photosynthesis in three taxonomically and ecologically diverse microbial mats

    NASA Technical Reports Server (NTRS)

    Cockell, C. S.; Rothschild, L. J.

    1999-01-01

    Photosynthetic primary production, the basis of most global food chains, is inhibited by UV radiation. Evaluating UV inhibition is therefore important for assessing the role of natural levels of UV radiation in regulating ecosystem behavior as well as the potential impact of stratospheric ozone depletion on global ecosystems. As both photosynthesis and UV fluxes are subject to diurnal variations, we examined the diurnal variability of the effect of UV radiation on photosynthesis in three diverse algal mats. In one of the mats (Cyanidium caldarium) a small mean decrease in primary productivity over the whole day occurred when both UVA and UVB were screened out. In two of the mats (Lyngbya aestuarii and Zygogonium sp.) we found a mean increase in the total primary productivity over the day when UVB alone was screened and a further increase when UVA and UVB were both screened out. Variations in the effects of UV radiation were found at different times of the day. This diurnal variability may be because even under the same solar radiation flux, there are different factors that may control photosynthetic rate, including nutritional status and other physiological processes in the cell. The results show the importance of assessing the complete diurnal productivity. For some of the time points the increase in the mean was still within the standard deviations in primary productivity, illustrating the difficulty in dissecting UV effects from other natural variations.

  13. Search for low-latitude atmospheric hydrocarbon variations on Jupiter from Juno-UVS measurements

    NASA Astrophysics Data System (ADS)

    Hue, V.; Gladstone, R.; Greathouse, T.; Versteeg, M.; Davis, M. W.; Gerard, J. C. M. C.; Grodent, D. C.; Bonfond, B.; Bolton, S. J.; Levin, S.; Connerney, J. E. P.

    2016-12-01

    The Juno mission offers the opportunity to study Jupiter, from its inner structure, up to its magnetospheric environment. Juno was launched on August 2011 and its Jupiter orbit insertion (JOI) occurred on July 4th 2016. The nominal Juno mission involves 35 science polar-orbits of 14-days period, with perijove and apojove distances located at 0.06 Rj and 45 Rj, respectively. Juno-UVS is a UV spectrograph with a bandpass of 70<λ<205 nm, designed to characterize Jupiter UV emissions. One of the main additions of UVS compared to its predecessors (New Horizons- and Rosetta- Alice, LRO-LAMP) is a 2.54 mm tantalum shielding, to protect it from the harsh radiation environment at Jupiter, and a scan mirror, to allow for targeting specific auroral and atmospheric features at +/- 30° perpendicular to the Juno spin plane. It will provide new constraints on Jupiter's auroral morphology, spectral features, and vertical structure, while providing remote-sensing constraints for the onboard waves and particle instruments. It will also be used to probe upper-atmospheric composition through absorption features found in the UV spectra using reflected solar UV radiation. For example, stratospheric hydrocarbons such as C2H2 and C2H6 are known to absorb significantly in the 150-180 nm regions, and these absorption features can be used to determine their abundances. We will present our search for the spectroscopic features seen in Jupiter's reflected sunlight during the first perijove.

  14. Anthropogenic changes in the surface all-sky UV-B radiation through 1850-2005 simulated by an Earth system model

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Takemura, T.; Sudo, K.; Yokohata, T.; Kawase, H.

    2012-06-01

    The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280-315 nm) radiation through 1850-2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and deforestation regions. Furthermore, changes in ozone transport in the lower stratosphere, which is induced by increasing greenhouse gas concentrations, increase ozone concentration in the extratropical upper troposphere and lower stratosphere. These transient changes work to decrease the amount of UV-B reaching the Earth's surface, counteracting the well-known effect increasing UV-B due to stratospheric ozone depletion, which developed rapidly after ca. 1980. As a consequence, the surface UV-B radiation change between 1850 and 2000 is negative in the tropics and NH extratropics and positive in the SH extratropics. Comparing the contributions of ozone and aerosol changes to the UV-B change, the transient change in ozone absorption of UV-B mainly determines the total change in the surface UV-B radiation at most locations. On the other hand, the aerosol direct and indirect effects on UV-B play an equally important role to that of ozone in the NH mid-latitudes and tropics. A typical example is East Asia (25° N-60° N and 120° E-150° E), where the effect of aerosols (ca. 70%) dominates the total UV-B change.

  15. Anthropogenic changes in the surface all-sky UV-B radiation through 1850-2005 simulated by an Earth system model

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Takemura, T.; Sudo, K.; Yokohata, T.; Kawase, H.

    2012-02-01

    The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280-315 nm) radiation through 1850-2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and deforestation regions. Furthermore, changes in ozone transport in the lower stratosphere, which is induced by increasing greenhouse gas concentrations, increase ozone concentration in the extratropical upper troposphere and lower stratosphere. These transient changes work to decrease the amount of UV-B reaching the Earth's surface, counteracting the well-known effect increasing UV-B due to stratospheric ozone depletion, which developed rapidly after ca. 1980. As a consequence, the surface all-sky UV-B radiation change between 1850 and 2000 is negative in the tropics and NH extratropics and positive in the SH extratropics. Comparing the contributions of ozone and aerosol changes to the UV-B change, the transient change in ozone absorption of UV-B mainly determines the total change in the surface all-sky UV-B radiation at most locations. On the other hand, the aerosol direct and indirect effects on UV-B play an equally important role to that of ozone in the NH mid-latitudes and tropics. A typical example is East Asia (25° N-60° N and 120° E-150° E), where the effect of aerosols (ca. 70%) dominates the total UV-B change.

  16. Radiative entropy generation in a gray absorbing, emitting, and scattering planar medium at radiative equilibrium

    NASA Astrophysics Data System (ADS)

    Sadeghi, Pegah; Safavinejad, Ali

    2017-11-01

    Radiative entropy generation through a gray absorbing, emitting, and scattering planar medium at radiative equilibrium with diffuse-gray walls is investigated. The radiative transfer equation and radiative entropy generation equations are solved using discrete ordinates method. Components of the radiative entropy generation are considered for two different boundary conditions: two walls are at a prescribed temperature and mixed boundary conditions, which one wall is at a prescribed temperature and the other is at a prescribed heat flux. The effect of wall emissivities, optical thickness, single scattering albedo, and anisotropic-scattering factor on the entropy generation is attentively investigated. The results reveal that entropy generation in the system mainly arises from irreversible radiative transfer at wall with lower temperature. Total entropy generation rate for the system with prescribed temperature at walls remarkably increases as wall emissivity increases; conversely, for system with mixed boundary conditions, total entropy generation rate slightly decreases. Furthermore, as the optical thickness increases, total entropy generation rate remarkably decreases for the system with prescribed temperature at walls; nevertheless, for the system with mixed boundary conditions, total entropy generation rate increases. The variation of single scattering albedo does not considerably affect total entropy generation rate. This parametric analysis demonstrates that the optical thickness and wall emissivities have a significant effect on the entropy generation in the system at radiative equilibrium. Considering the parameters affecting radiative entropy generation significantly, provides an opportunity to optimally design or increase overall performance and efficiency by applying entropy minimization techniques for the systems at radiative equilibrium.

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

    EPA Science Inventory

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

  18. Phenomenon of period-doubling in holographic periodic structures exposed to UV radiation

    NASA Astrophysics Data System (ADS)

    Gulyaev, Sergey N.; Isaev, Igor V.

    2001-02-01

    This paper presents the experimental study of the period- doubling phenomenon occurring during the multi-cycle processing procedure incorporating the exposure of Ag halide photoemulsion with the primary recorded holographic structure to the short-wave UV radiation, washing and drying. It is suggested that the simultaneous presence of two contrary photochemical processes -- photodecomposition and radiation hardening in the gelatin results in instability of the primary holographic structure and in the formation of the spatial subharmonic of the surface relief. The phenomenon may be considered as a process of the self-organization initiated by instability of the macrostructure on a rearrangement of the microstructure on the molecule level. The period-doubling phenomenon has been found to occur in the experiments with the UV sources of a various spectral composition -- the mercury- vapor lamp and the excimer lamps operating on the mixtures of Xe+Cl2 and Kr+Cl2.

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

    EPA Science Inventory

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

  20. Assessment of capabilities of multiangle imaging photo-polarimetry for atmospheric correction in presence of absorbing aerosols

    NASA Astrophysics Data System (ADS)

    Kalashnikova, O. V.; Garay, M. J.; Xu, F.; Seidel, F. C.; Diner, D. J.

    2015-12-01

    Satellite remote sensing of ocean color is a critical tool for assessing the productivity of marine ecosystems and monitoring changes resulting from climatic or environmental influences. Yet water-leaving radiance comprises less than 10% of the signal measured from space, making correction for absorption and scattering by the intervening atmosphere imperative. Traditional ocean color retrieval algorithms utilize a standard set of aerosol models and the assumption of negligible water-leaving radiance in the near-infrared. Modern improvements have been developed to handle absorbing aerosols such as urban particulates in coastal areas and transported desert dust over the open ocean, where ocean fertilization can impact biological productivity at the base of the marine food chain. Even so, imperfect knowledge of the absorbing aerosol optical properties or their height distribution results in well-documented sources of error. In the UV, the problem of UV-enhanced absorption and nonsphericity of certain aerosol types are amplified due to the increased Rayleigh and aerosol optical depth, especially at off-nadir view angles. Multi-angle spectro-polarimetric measurements have been advocated as an additional tool to better understand and retrieve the aerosol properties needed for atmospheric correction for ocean color retrievals. The central concern of the work to be described is the assessment of the effects of absorbing aerosol properties on water leaving radiance measurement uncertainty by neglecting UV-enhanced absorption of carbonaceous particles and by not accounting for dust nonsphericity. In addition, we evaluate the polarimetric sensitivity of absorbing aerosol properties in light of measurement uncertainties achievable for the next generation of multi-angle polarimetric imaging instruments, and demonstrate advantages and disadvantages of wavelength selection in the UV/VNIR range. The phase matrices for the spherical smoke particles were calculated using a standard

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Faster recovery of a diatom from UV damage under ocean acidification.

    PubMed

    Wu, Yaping; Campbell, Douglas A; Gao, Kunshan

    2014-11-01

    Diatoms are the most important group of primary producers in marine ecosystems. As oceanic pH declines and increased stratification leads to the upper mixing layer becoming shallower, diatoms are interactively affected by both lower pH and higher average exposures to solar ultraviolet radiation. The photochemical yields of a model diatom, Phaeodactylum tricornutum, were inhibited by ultraviolet radiation under both growth and excess light levels, while the functional absorbance cross sections of the remaining photosystem II increased. Cells grown under ocean acidification (OA) were less affected during UV exposure. The recovery of PSII under low photosynthetically active radiation was much faster than in the dark, indicating that photosynthetic processes were essential for the full recovery of photosystem II. This light dependent recovery required de novo synthesized protein. Cells grown under ocean acidification recovered faster, possibly attributable to higher CO₂ availability for the Calvin cycle producing more resources for repair. The lower UV inhibition combined with higher recovery rate under ocean acidification could benefit species such as P.tricornutum, and change their competitiveness in the future ocean. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Effect of UV radiation on habitat selection by Girella laevifrons and Graus nigra (Kyphosidae).

    PubMed

    Pulgar, J; Lagos, P; Maturana, D; Valdés, M; Aldana, M; Pulgar, V M

    2015-02-01

    The effect of UV radiation on habitat use of two species of intertidal fishes that inhabit the same pools but exhibit different activity levels and diets was measured: the highly active omnivorous Girella laevifrons and the cryptic carnivorous Graus nigra. Individuals of each species were acclimated to a tank divided in three sections with different illumination; no light (NL), ultraviolet light (UV) and white light (WL), and the time spent and number of visits to each section were recorded. Although both species preferred the NL section, G. laevifrons spent more time in UV and less time in WL compared with G. nigra; G. laevifrons also displayed higher number of visits to UV, suggesting a different tendency in space use in response to UV exposure in intertidal fishes. © 2015 The Fisheries Society of the British Isles.

  4. Cooling systems and hybrid A/C systems using an electromagnetic radiation-absorbing complex

    DOEpatents

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2015-05-19

    A method for powering a cooling unit. The method including applying electromagnetic (EM) radiation to a complex, where the complex absorbs the EM radiation to generate heat, transforming, using the heat generated by the complex, a fluid to vapor, and sending the vapor from the vessel to a turbine coupled to a generator by a shaft, where the vapor causes the turbine to rotate, which turns the shaft and causes the generator to generate the electric power, wherein the electric powers supplements the power needed to power the cooling unit

  5. IPR 1.0: an efficient method for calculating solar radiation absorbed by individual plants in sparse heterogeneous woody plant communities

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Chen, W.; Li, J.

    2013-12-01

    Climate change may alter the spatial distribution, composition, structure, and functions of plant communities. Transitional zones between biomes, or ecotones, are particularly sensitive to climate change. Ecotones are usually heterogeneous with sparse trees. The dynamics of ecotones are mainly determined by the growth and competition of individual plants in the communities. Therefore it is necessary to calculate solar radiation absorbed by individual plants for understanding and predicting their responses to climate change. In this study, we developed an individual plant radiation model, IPR (version 1.0), to calculate solar radiation absorbed by individual plants in sparse heterogeneous woody plant communities. The model is developed based on geometrical optical relationships assuming crowns of woody plants are rectangular boxes with uniform leaf area density. The model calculates the fractions of sunlit and shaded leaf classes and the solar radiation absorbed by each class, including direct radiation from the sun, diffuse radiation from the sky, and scattered radiation from the plant community. The solar radiation received on the ground is also calculated. We tested the model by comparing with the analytical solutions of random distributions of plants. The tests show that the model results are very close to the averages of the random distributions. This model is efficient in computation, and is suitable for ecological models to simulate long-term transient responses of plant communities to climate change.

  6. Comparative sensitivity to UV-B radiation of two Bacillus thuringiensis subspecies and other Bacillus sp.

    PubMed

    Myasnik, M; Manasherob, R; Ben-Dov, E; Zaritsky, A; Margalith, Y; Barak, Z

    2001-08-01

    Susceptibility of Bacillus thuringiensis spores and toxins to the UV-B range (280--330 nm) of the solar spectrum reaching Earth's surface may be responsible for its inactivation and low persistence in nature. Spores of the mosquito larvicidal B. thuringiensis subsp. israelensis were significantly more resistant to UV-B than spores of the lepidopteran-active subsp. kurstaki. Spores of subsp. israelensis were as resistant to UV-B as spores of B. subtilis and more resistant than spores of the closely related B. cereus and another mosquito larvicidal species B. sphaericus. Sensitivity of B. thuringiensis subsp. israelensis spores to UV-B radiation depended upon their culture age; 24-h cultures, approaching maximal larvicidal activity, were still sensitive. Maximal resistance to UV-B was achieved only at 48 h.

  7. Sensing and Responding to UV-A in Cyanobacteria

    PubMed Central

    Moon, Yoon-Jung; Kim, Seung Il; Chung, Young-Ho

    2012-01-01

    Ultraviolet (UV) radiation can cause stresses or act as a photoregulatory signal depending on its wavelengths and fluence rates. Although the most harmful effects of UV on living cells are generally attributed to UV-B radiation, UV-A radiation can also affect many aspects of cellular processes. In cyanobacteria, most studies have concentrated on the damaging effect of UV and defense mechanisms to withstand UV stress. However, little is known about the activation mechanism of signaling components or their pathways which are implicated in the process following UV irradiation. Motile cyanobacteria use a very precise negative phototaxis signaling system to move away from high levels of solar radiation, which is an effective escape mechanism to avoid the detrimental effects of UV radiation. Recently, two different UV-A-induced signaling systems for regulating cyanobacterial phototaxis were characterized at the photophysiological and molecular levels. Here, we review the current understanding of the UV-A mediated signaling pathways in the context of the UV-A perception mechanism, early signaling components, and negative phototactic responses. In addition, increasing evidences supporting a role of pterins in response to UV radiation are discussed. We outline the effect of UV-induced cell damage, associated signaling molecules, and programmed cell death under UV-mediated oxidative stress. PMID:23208372

  8. Frequency dependence of the acoustic radiation force acting on absorbing cylindrical shells.

    PubMed

    Mitri, Farid G

    2005-02-01

    The frequency dependence of the radiation force function Y(p) for absorbing cylindrical shells suspended in an inviscid fluid in a plane incident sound field is analysed, in relation to the thickness and the content of their interior hollow region. The theory is modified to include the effect of hysteresis type absorption of compressional and shear waves in the material. The results of numerical calculations are presented for two viscoelastic (lucite and phenolic polymer) materials, with the hollow region filled with water or air indicating how damping and change of the interior fluid inside the shell's hollow region affect the acoustic radiation force. The acoustic radiation force acting on cylindrical lucite shells immersed in a high density fluid (in this case mercury) and filled with water in their hollow region, is also studied.

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

    PubMed

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

    2006-07-05

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

  10. Rapid transcriptome responses of maize (Zea mays) to UV-B in irradiated and shielded tissues

    PubMed Central

    Casati, Paula; Walbot, Virginia

    2004-01-01

    Background Depletion of stratospheric ozone has raised terrestrial levels of ultraviolet-B radiation (UV-B), an environmental change linked to an increased risk of skin cancer and with potentially deleterious consequences for plants. To better understand the processes of UV-B acclimation that result in altered plant morphology and physiology, we investigated gene expression in different organs of maize at several UV-B fluence rates and exposure times. Results Microarray hybridization was used to assess UV-B responses in directly exposed maize organs and organs shielded by a plastic that absorbs UV-B. After 8 hours of high UV-B, the abundance of 347 transcripts was altered: 285 were increased significantly in at least one organ and 80 were downregulated. More transcript changes occurred in directly exposed than in shielded organs, and the levels of more transcripts were changed in adult compared to seedling tissues. The time course of transcript abundance changes indicated that the response kinetics to UV-B is very rapid, as some transcript levels were altered within 1 hour of exposure. Conclusions Most of the UV-B regulated genes are organ-specific. Because shielded tissues, including roots, immature ears, and leaves, displayed altered transcriptome profiles after exposure of the plant to UV-B, some signal(s) must be transmitted from irradiated to shielded tissues. These results indicate that there are integrated responses to UV-B radiation above normal levels. As the same total UV-B irradiation dose applied at three intensities elicited different transcript profiles, the transcriptome changes exhibit threshold effects rather than a reciprocal dose-effect response. Transcriptome profiling highlights possible signaling pathways and molecules for future research. PMID:15003119

  11. UV radiation and CH4 gas detection with a single ZnO:Pd nanowire

    NASA Astrophysics Data System (ADS)

    Lupan, O.; Adelung, R.; Postica, V.; Ababii, N.; Chow, L.; Viana, B.; Pauporté, T.

    2017-02-01

    There is an increasing demand for sensors to monitor environmental levels of ultraviolet (UV) radiation and pollutant gases. In this work, an individual nanowire of Pd modified ZnO nanowire (ZnO:Pd NW) was integrated in a nanosensor device for efficient and fast detection of UV light and CH4 gas at room temperature. Crystalline ZnO:Pd nanowire/nanorod arrays were synthesized onto fluorine doped tin oxide (FTO) substrates by electrochemical deposition (ECD) at relative low-temperatures (90 °C) with different concentrations of PdCl2 in electrolyte solution and investigated by SEM and EDX. Nanodevices were fabricated using dual beam focused electron/ion beam (FIB/SEM) system and showed improved UV radiation response compared to pristine ZnO NW, reported previously by our group. The UV response was increased by one order in magnitude (≈ 11) for ZnO:Pd NW. Gas sensing measurements demonstrated a higher gas response and rapidity to methane (CH4 gas, 100 ppm) at room temperature, showing promising results for multifunctional applications. Also, due to miniature size and ultra-low power consumption of these sensors, it is possible to integrate them into portable devices easily, such as smartphones, digital clock, flame detection, missile lunching and other smart devices.

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

    Treesearch

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

    2014-01-01

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

  13. Long-term exposure to enhanced UV-B radiation has no significant effects on growth or secondary compounds of outdoor-grown Scots pine and Norway spruce seedlings.

    PubMed

    Turtola, Satu; Sallas, Leena; Holopainen, Jarmo K; Julkunen-Tiitto, Riitta; Kainulainen, Pirjo

    2006-11-01

    The effects of long-term enhanced UV-B radiation on growth and secondary compounds of two conifer species were studied in an outdoor experiment. Scots pine (Pinus sylvestris) seedlings were exposed for two growing seasons and Norway spruce (Picea abies) seedlings for three growing seasons to supplemental UV-B radiation, corresponding to a 30% increase in ambient UV-B radiation. The experiment also included appropriate controls for ambient and increased UV-A radiation. Enhanced UV-B did not affect the growth of the conifer seedlings. In addition, neither the concentrations of terpenes and phenolics in the needles nor the concentrations of terpenes in the wood were affected. However, in the UV-A control treatment the concentrations of diterpenes in the wood of Scots pine decreased significantly compared to the ambient control. Apparently, a small increase in UV-B radiation has no significant effects on the secondary compounds and growth of Scots pine and Norway spruce seedlings.

  14. Oxidative damage in response to natural levels of UV-B radiation in larvae of the tropical sea urchin Tripneustes gratilla.

    PubMed

    Lister, Kathryn Naomi; Lamare, Miles D; Burritt, David J

    2010-01-01

    To assess the effects of UV radiation (280-400nm) on development, oxidative damage and antioxidant defence in larvae of the tropical sea urchin Tripneustes gratilla, a field experiment was conducted at two depths in Aitutaki, Cook Islands (18.85°S, 159.75°E) in May 2008. Compared with field controls (larvae shielded from UV-R but exposed to VIS-radiation), UV-B exposure resulted in developmental abnormality and increases in oxidative damage to proteins (but not lipids) in embryos of T. gratilla held at 1m depth. Results also indicated that larvae had the capacity to increase the activities of protective antioxidant enzymes when exposed to UV-B. The same trends in oxidative damage and antioxidant defence were observed for embryos held at 4m, although the differences were smaller and more variable. In contrast to UV-B exposure, larvae exposed to UV-A only showed no significant increases in abnormality or oxidative damage to lipids and proteins compared with field controls. This was true at both experimental depths. Furthermore, exposure to UV-A did not cause a significant increase in the activities of antioxidants. This study indicates that oxidative stress is an important response of tropical sea urchin larvae to exposure to UV radiation. © 2010 The Authors. Journal Compilation. The American Society of Photobiology.

  15. The effectiveness of UV-C radiation for facility-wide environmental disinfection to reduce health care-acquired infections.

    PubMed

    Napolitano, Nathanael A; Mahapatra, Tanmay; Tang, Weiming

    2015-12-01

    Health care-acquired infections (HAIs) constitute an increasing threat for patients worldwide. Potential contributors of HAIs include environmental surfaces in health care settings, where ultraviolet-C radiation (UV-C) is commonly used for disinfection. This UV-C intervention-based pilot study was conducted in a hospital setting to identify any change in the incidence of HAIs before and after UV-C intervention, and to determine the effectiveness of UV-C in reducing pathogens. In a hospital in Culver City, CA, during 2012-2013, bactericidal doses of UV-C radiation (254 nm) were delivered through a UV-C-based mobile environmental decontamination unit. The UV-C dosing technology and expertise of the specifically trained personnel were provided together as a dedicated service model by a contracted company. The incidence of HAIs before and after the intervention period were determined and compared. The dedicated service model dramatically reduced HAIs (incidence difference, 1.3/1000 patient-days, a 34.2% reduction). Reductions in the total number and incidence proportions (28.8%) of HAIs were observed after increasing and maintaining the coverage of UV-C treatments. The dedicated service model was found to be effective in decreasing the incidence of HAIs, which could reduce disease morbidity and mortality in hospitalized patients. This model provides a continuously monitored and frequently UV-C-treated patient environment. This approach to UV-C disinfection was associated with a decreased incidence of HAIs. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  16. Effects of UV-B radiation on leaf hair traits of invasive plants-Combining historical herbarium records with novel remote sensing data.

    PubMed

    Václavík, Tomáš; Beckmann, Michael; Cord, Anna F; Bindewald, Anja M

    2017-01-01

    Ultraviolet-B (UV-B) radiation is a key but under-researched environmental factor that initiates diverse responses in plants, potentially affecting their distribution. To date, only a few macroecological studies have examined adaptations of plant species to different levels of UV-B. Here, we combined herbarium specimens of Hieracium pilosella L. and Echium vulgare L. with a novel UV-B dataset to examine differences in leaf hair traits between the plants' native and alien ranges. We analysed scans of 336 herbarium specimens using standardized measurements of leaf area, hair density (both species) and hair length (H. pilosella only). While accounting for other bioclimatic variables (i.e. temperature, precipitation) and effects of herbivory, we examined whether UV-B exposure explains the variability and geographical distribution of these traits in the native (Northern Hemisphere) vs. the alien (Southern Hemisphere) range. UV-B explained the largest proportion of the variability and geographical distribution of hair length in H. pilosella (relative influence 67.1%), and hair density in E. vulgare (66.2%). Corresponding with higher UV-B, foliar hairs were 25% longer for H. pilosella and 25% denser for E. vulgare in records from the Southern as compared to those from the Northern Hemisphere. However, focusing on each hemisphere separately or controlling for its effect in a regression analysis, we found no apparent influence of UV-B radiation on hair traits. Thus, our findings did not confirm previous experimental studies which suggested that foliar hairs may respond to higher UV-B intensities, presumably offering protection against detrimental levels of radiation. We cannot rule out UV-B radiation as a possible driver because UV-B radiation was the only considered variable that differed substantially between the hemispheres, while bioclimatic conditions (e.g. temperature, precipitation) and other considered variables (herbivory damage, collection date) were at similar

  17. Influence of the dark/light rhythm on the effects of UV radiation in the eyestalk of the crab Neohelice granulata.

    PubMed

    Vargas, Marcelo Alves; Geish, Marcio Alberto; Maciel, Fabio Everton; Cruz, Bruno Pinto; Filgueira, Daza de Moraes Vaz Batista; Ferreira, Gabrielle de Jesus; Nery, Luiz Eduardo Maia; Allodi, Silvana

    2010-04-01

    Crustaceans are interesting models to study the effects of ultraviolet (UV) radiation, and many species may be used as biomarkers for aquatic contamination of UV radiation reaching the surface of the Earth. Here, we investigated cell damage in the visual system of crabs Neohelice granulata that were acclimated to either 12L:12D, constant light, or constant dark, and were exposed to UVA or UVB at 12:00h (noon). The production of reactive oxygen species (ROS), antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO) damage, catalase activity, and pigment dispersion in the eye were evaluated. No significant differences from the three groups of controls (animals acclimated to 12L:12D, or in constant light, or not exposed to UV radiation) were observed in animals acclimated to 12L:12D, however, crabs acclimated to constant light and exposed to UV radiation for 30min showed a significant increase in ROS concentration, catalase activity, and LPO damage, but a decrease in ACAP compared with the controls. Crabs acclimated to constant darkness and exposed to UV for 30min showed a significantly increased ROS concentration and LPO damage, but the ACAP and catalase activity did not differ from the controls (animals kept in the dark while the experimental group was being exposed to UV radiation). Pigment dispersion in the pigment cells of eyes of animals acclimated to constant light was also observed. The results indicate that UVA and UVB alter specific oxidative parameters; however, the cell damage is more evident in animals deviated from the normal dark/light rhythm.

  18. Effect of Index of Refraction on Radiation Characteristics in a Heated Absorbing, Emitting, and Scattering Layer

    NASA Technical Reports Server (NTRS)

    Siegel, R.; Spuckler, C. M.

    1992-01-01

    The effect of the index of refraction on the temperature distribution and radiative heat flux in semitransparent materials, such as some ceramics, is investigated analytically. In the case considered here, a plane layer of a ceramic material is subjected to external radiative heating incident on each of its surfaces; the material emits, absorbs, and isotropically scatters radiation. It is shown that, for radiative equilibrium in a gray layer with diffuse interfaces, the temperature distribution and radiative heat flux for any index of refraction can be obtained in a simple manner from the results for an index of refraction of unity.

  19. The TROPOMI surface UV algorithm

    NASA Astrophysics Data System (ADS)

    Lindfors, Anders V.; Kujanpää, Jukka; Kalakoski, Niilo; Heikkilä, Anu; Lakkala, Kaisa; Mielonen, Tero; Sneep, Maarten; Krotkov, Nickolay A.; Arola, Antti; Tamminen, Johanna

    2018-02-01

    The TROPOspheric Monitoring Instrument (TROPOMI) is the only payload of the Sentinel-5 Precursor (S5P), which is a polar-orbiting satellite mission of the European Space Agency (ESA). TROPOMI is a nadir-viewing spectrometer measuring in the ultraviolet, visible, near-infrared, and the shortwave infrared that provides near-global daily coverage. Among other things, TROPOMI measurements will be used for calculating the UV radiation reaching the Earth's surface. Thus, the TROPOMI surface UV product will contribute to the monitoring of UV radiation by providing daily information on the prevailing UV conditions over the globe. The TROPOMI UV algorithm builds on the heritage of the Ozone Monitoring Instrument (OMI) and the Satellite Application Facility for Atmospheric Composition and UV Radiation (AC SAF) algorithms. This paper provides a description of the algorithm that will be used for estimating surface UV radiation from TROPOMI observations. The TROPOMI surface UV product includes the following UV quantities: the UV irradiance at 305, 310, 324, and 380 nm; the erythemally weighted UV; and the vitamin-D weighted UV. Each of these are available as (i) daily dose or daily accumulated irradiance, (ii) overpass dose rate or irradiance, and (iii) local noon dose rate or irradiance. In addition, all quantities are available corresponding to actual cloud conditions and as clear-sky values, which otherwise correspond to the same conditions but assume a cloud-free atmosphere. This yields 36 UV parameters altogether. The TROPOMI UV algorithm has been tested using input based on OMI and the Global Ozone Monitoring Experiment-2 (GOME-2) satellite measurements. These preliminary results indicate that the algorithm is functioning according to expectations.

  20. Variations of metabolites and proteome in Lonicera japonica Thunb. buds and flowers under UV radiation.

    PubMed

    Zhu, Wei; Zheng, Wen; Hu, Xingjiang; Xu, Xiaobao; Zhang, Lin; Tian, Jingkui

    2017-04-01

    Lonicera japonica Thunb., also known as Jin Yin Hua and Japanese honeysuckle, is used as a herbal medicine in Asian countries. Its flowers have been used in folk medicine in the clinic and in making food or healthy beverages for over 1500years in China. To investigate the molecular processes involved in L. japonica development from buds to flowers exposed to UV radiation, a comparative proteomics analysis was performed. Fifty-four proteins were identified as differentially expressed, including 42 that had increased expression and 12 that had decreased expression. The levels of the proteins related to glycolysis, TCA/organic acid transformation, major carbohydrate metabolism, oxidative pentose phosphate, stress, secondary metabolism, hormone, and mitochondrial electron transport were increased during flower opening process after exposure to UV radiation. Six metabolites in L. japonica buds and flowers were identified and relatively quantified using LC-MS/MS. The antioxidant activity was performed using a 1,1-diphenyl-2-picrylhydrazyl assay, which revealed that L. japonica buds had more activity than the UV irradiated flowers. This suggests that UV-B radiation induces production of endogenous ethylene in L. japonica buds, thus facilitating blossoming of the buds and activating the antioxidant system. Additionally, the higher metabolite contents and antioxidant properties of L. japonica buds indicate that the L. japonica bud stage may be a more optimal time to harvest than the flower stage when using for medicinal properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Limnoithona sinensis as refuge for bacteria: protection from UV radiation and chlorine disinfection in drinking water treatment.

    PubMed

    Lin, Tao; Cai, Bo; Chen, Wei

    2014-11-01

    In this study, we tested the potential of Limnoithona sinensis to provide its attached bacteria refuge against disinfection. The experimental results indicated that in water devoid of zooplankton, both UV radiation and chlorine disinfection significantly decreased the viability of free-living bacteria. In the presence of L. sinensis, however, the attached bacteria could survive and rapidly recover from disinfection. This demonstrated that L. sinensis provided protection from external damage to various aquatic bacteria that were attached to its body. The surviving bacteria remained on L. sinensis after disinfection exposure, which enabled a rapid increase in the bacterial population followed by their subsequent release into the surrounding water. Compared with UV radiation, chlorine disinfection was more effective in terms of inactivating attached bacteria. Both UV radiation and chlorine disinfection had little effect in terms of preventing the spread of undesirable bacteria, due to the incomplete inactivation of the bacteria associated with L. sinensis.

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

    PubMed

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

    2017-05-01

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

  3. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of-the-art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments, and or heavy phase change material heat exchangers for thermal storage. These approaches can lead to large loss of water and a significant mass penalties for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. This paper describes analysis models to predict performance and optimize the size of the SEAR system, estimated size and mass of key components, and an assessment of potential mass savings compared with alternative thermal management approaches. We also describe a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  4. Radiation absorbed by a vertical cylinder in complex outdoor environments under clear sky conditions

    NASA Astrophysics Data System (ADS)

    Krys, S. A.; Brown, R. D.

    1990-06-01

    Research was conducted into the estimation of radiation absorbed by a vertical cylinder in complex outdoor environments under clear sky conditions. Two methods of estimation were employed: a cylindrical radiation thermometer (CRT) and model developed by Brown and Gillespie (1986), and the weather station model. The CRT produced an integrated temperature reading from which the radiant environment could be estimated successfully given simultaneous measurements of air temperature and wind speed. The CRT estimates compared to the measured radiation gave a correlation coefficient of 0.9499, SE=19.8 W/m2, α=99.9%. The physically-based equations (weather station model)require the inputs of data from a near by weather station and site characteristics to estimate radiation absorbed by a vertical cylinder. The correlation coefficient for the weather station model is 0.9529, SE=16.8 W/m2, α=99.9%. This model estimates short wave and long wave radiation separately; hence, this allowed further comparison to measured values. The short wave radiation was very successfully estimated: R=0.9865, SE=10.0 W/m2, α=99.9%. The long wave radiation estimates were also successful: R=0.8654, SE=15.7 W/m2, and α=99.9%. Though the correlation coefficient and standard error may suggest inaccuracy to the micrometeorologist, these estimation techniques would be extremely useful as predictors of human thermal comfort which is not a precise measure buut defined by a range. The reported methods require little specialized knowledge of micrometeorology and are vehicles for the designers of outdoor spaces to measure accurately the inherent radiant environment of outdoor spaces and provide a measurement technique to simulate or model the effect of various landscape elements on planned environments.

  5. IPR 1.0: an efficient method for calculating solar radiation absorbed by individual plants in sparse heterogeneous woody plant communities

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Chen, W.; Li, J.

    2014-07-01

    Climate change may alter the spatial distribution, composition, structure and functions of plant communities. Transitional zones between biomes, or ecotones, are particularly sensitive to climate change. Ecotones are usually heterogeneous with sparse trees. The dynamics of ecotones are mainly determined by the growth and competition of individual plants in the communities. Therefore it is necessary to calculate the solar radiation absorbed by individual plants in order to understand and predict their responses to climate change. In this study, we developed an individual plant radiation model, IPR (version 1.0), to calculate solar radiation absorbed by individual plants in sparse heterogeneous woody plant communities. The model is developed based on geometrical optical relationships assuming that crowns of woody plants are rectangular boxes with uniform leaf area density. The model calculates the fractions of sunlit and shaded leaf classes and the solar radiation absorbed by each class, including direct radiation from the sun, diffuse radiation from the sky, and scattered radiation from the plant community. The solar radiation received on the ground is also calculated. We tested the model by comparing with the results of random distribution of plants. The tests show that the model results are very close to the averages of the random distributions. This model is efficient in computation, and can be included in vegetation models to simulate long-term transient responses of plant communities to climate change. The code and a user's manual are provided as Supplement of the paper.

  6. Effects of ultraviolet radiation on photosynthetic performance and N2 fixation in Trichodesmium erythraeum IMS 101

    NASA Astrophysics Data System (ADS)

    Cai, Xiaoni; Hutchins, David A.; Fu, Feixue; Gao, Kunshan

    2017-10-01

    Biological effects of ultraviolet radiation (UVR; 280-400 nm) on marine primary producers are of general concern, as oceanic carbon fixers that contribute to the marine biological CO2 pump are being exposed to increasing UV irradiance due to global change and ozone depletion. We investigated the effects of UV-B (280-320 nm) and UV-A (320-400 nm) on the biogeochemically critical filamentous marine N2-fixing cyanobacterium Trichodesmium (strain IMS101) using a solar simulator as well as under natural solar radiation. Short exposure to UV-B, UV-A, or integrated total UVR significantly reduced the effective quantum yield of photosystem II (PSII) and photosynthetic carbon and N2 fixation rates. Cells acclimated to low light were more sensitive to UV exposure compared to high-light-grown ones, which had more UV-absorbing compounds, most likely mycosporine-like amino acids (MAAs). After acclimation under natural sunlight, the specific growth rate was lower (by up to 44 %), MAA content was higher, and average trichome length was shorter (by up to 22 %) in the full spectrum of solar radiation with UVR, than under a photosynthetically active radiation (PAR) alone treatment (400-700 nm). These results suggest that prior shipboard experiments in UV-opaque containers may have substantially overestimated in situ nitrogen fixation rates by Trichodesmium, and that natural and anthropogenic elevation of UV radiation intensity could significantly inhibit this vital source of new nitrogen to the current and future oligotrophic oceans.

  7. An ultraviolet simulator for the incident Martian surface radiation and its applications

    NASA Astrophysics Data System (ADS)

    Kolb, C.; Abart, R.; Bérces, A.; Garry, J. R. C.; Hansen, A. A.; Hohenau, W.; Kargl, G.; Lammer, H.; Patel, M. R.; Rettberg, P.; Stan-Lotter, H.

    2005-10-01

    Ultraviolet (UV) radiation can act on putative organic/biological matter at the Martian surface in several ways. Only absorbed, but not transmitted or reflected, radiation energy can be photo-chemically effective. The most important biological UV effects are due to photochemical reactions in nucleic acids, DNA or RNA, which constitute the genetic material of all cellular organisms and viruses. Protein or lipid effects generally play a minor role, but they are also relevant in some cases. UV radiation can induce wavelengths-specific types of DNA damage. At the same time it can also induce the photo-reversion reaction of a UV induced DNA photoproduct of nucleic acid bases, the pyrimidine dimers. Intense UVB and UVC radiation, experienced on early Earth and present-day Mars, has been revealed to be harmful to all organisms, including extremophile bacteria and spores. Moreover, the formation of oxidants, catalytically produced in the Martian environment through UV irradiation, may be responsible for the destruction of organic matter on Mars. Following this, more laboratory simulations are vital in order to investigate and understand UV effects on organic matter in the case of Mars. We have designed a radiation apparatus that simulates the anticipated Martian UV surface spectrum between 200 and 400 nm (UVC UVA). The system comprises a UV enhanced xenon arc lamp, special filter-sets and mirrors to simulate the effects of the Martian atmospheric column and dust loading. We describe the technical setup and performance of the system and discuss its uses for different applications. The design is focused on portability, therefore, the Mars-UV simulator represents a device for several different Mars simulation facilities with specific emphasis on Mars research topics.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    PubMed

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

    2015-12-01

    Populations of organisms routinely face abiotic selection pressures, and a central goal of evolutionary biology is to understand the mechanistic underpinnings of adaptive phenotypes. Ultraviolet radiation (UVR) is one of earth's most pervasive environmental stressors, potentially damaging DNA in any organism exposed to solar radiation. We explored mechanisms underlying differential survival following UVR exposure in genotypes of the water flea Daphnia melanica derived from natural ponds of differing UVR intensity. The UVR tolerance of a D. melanica genotype from a high-UVR habitat depended on the presence of visible and UV-A light wavelengths necessary for photoenzymatic repair of DNA damage, a repair pathway widely shared across the tree of life. We then measured the acquisition and repair of cyclobutane pyrimidine dimers, the primary form of UVR-caused DNA damage, in D. melanica DNA following experimental UVR exposure. We demonstrate that genotypes from high-UVR habitats repair DNA damage faster than genotypes from low-UVR habitats in the presence of visible and UV-A radiation necessary for photoenzymatic repair, but not in dark treatments. Because differences in repair rate only occurred in the presence of visible and UV-A radiation, we conclude that differing rates of DNA repair, and therefore differential UVR tolerance, are a consequence of variation in photoenzymatic repair efficiency. We then rule out a simple gene expression hypothesis for the molecular basis of differing repair efficiency, as expression of the CPD photolyase gene photorepair did not differ among D. melanica lineages, in both the presence and absence of UVR. © 2015 John Wiley & Sons Ltd.

  10. The optical effect of a semiconductor laser on protecting wheat from UV-B radiation damage.

    PubMed

    Qiu, Zong-Bo; Zhu, Xin-Jun; Li, Fang-Min; Liu, Xiao; Yue, Ming

    2007-07-01

    Lasers have been widely used in the field of biology along with the development of laser technology, but the mechanism of the bio-effect of lasers is not explicit. The objective of this paper was to test the optical effect of a laser on protecting wheat from UV-B damage. A patent instrument was employed to emit semiconductor laser (wavelength 650 nm) and incoherent red light, which was transformed from the semiconductor laser. The wavelength, power and lightfleck diameter of the incoherent red light are the same as those of the semiconductor laser. The semiconductor laser (wavelength 650 nm, power density 3.97 mW mm(-2)) and incoherent red light (wavelength 650 nm, power density 3.97 mW mm(-2)) directly irradiated the embryo of wheat seeds for 3 min respectively, and when the seedlings were 12-day-old they were irradiated by UV-B radiation (10.08 kJ m(-2)) for 12 h in the dark. Changes in the concentration of malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), glutathione (GSH), ascorbate (AsA), carotenoids (CAR), the production rate of superoxide radical (O(2)(-)), the activities of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and the growth parameters of seedlings (plant height, leaf area and fresh weight) were measured to test the optical effect of the laser. The results showed that the incoherent red light treatment could not enhance the activities of SOD, POD and CAT and the concentration of AsA and CAR. When the plant cells were irradiated by UV-B, the incoherent red light treatment could not eliminate active oxygen and prevent lipid peroxidation in wheat. The results also clearly demonstrate that the plant DNA was damaged by UV-B radiation and semiconductor laser irradiance had the capability to protect plants from UV-B-induced DNA damage, while the incoherent red light could not. This is the first investigation reporting the optical effect of a semiconductor laser on protecting wheat from UV-B radiation damage.

  11. The effects of gamma radiation, UV and visible light on ATP levels in yeast cells depend on cellular melanization.

    PubMed

    Bryan, Ruth; Jiang, Zewei; Friedman, Matthew; Dadachova, Ekaterina

    2011-10-01

    Previously we have shown that growth of melanized fungi is stimulated by low levels of gamma radiation. The goal of this study was to examine the effects of visible light, UV light, and gamma radiation on the energy level (ATP concentration) in melanized Cryptococcus neoformans cells. Melanized C. neoformans cells as well as non-melanized controls were subjected to visible, UV or gamma radiation, and ATP was quantified by measuring the amount of light emitted by the ATP-dependent reaction of luciferase with luciferin. We found that all three forms of radiation led to a reduction in the ATP levels in melanized C. neoformans cells. This points to a universal melanin-related mechanism underlying observation of ATP decrease in irradiated melanized cells. In contrast, in non-melanized cells visible light led to increase in ATP levels; gamma radiation did not cause any changes while UV exposure resulted in some ATP decrease, however, much less pronounced than in melanized cells. Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

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

    PubMed

    Bonzongo, Jean Claude J; Donkor, Augustine K

    2003-09-01

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

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

    PubMed Central

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

    2015-01-01

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

  15. UV actinometer film

    NASA Technical Reports Server (NTRS)

    Coulbert, C. D.; Gupta, A.; Pitts, J.

    1980-01-01

    Cumulative UV radiation can be measured by low-cost polymer film that is unaffacted by visible light. Useful for virtually any surface, film can help paint and plastics manufacturers determine how well their products stand up against UV radiation. Actinometer film uses photochemically sensitive compound that changes its chemical composition in response to solar radiation. Extent of chemical conversion depends on length exposure and can be measured by examining film sample with spectrophotometer. Film can be exposed from several seconds up to month.

  16. A refractory metamaterial absorber for ultra-broadband, omnidirectional and polarization-independent absorption in the UV-NIR spectrum.

    PubMed

    Huang, Yijia; Liu, Ling; Pu, Mingbo; Li, Xiong; Ma, Xiaoliang; Luo, Xiangang

    2018-05-03

    In this paper, efficient ultra-broadband absorption from ultraviolet (UV) to near infrared (NIR) is achieved using a metamaterial perfect absorber (MPA) with refractory constituents. Both simulated and experimental results indicate that this proposed MPA exhibits an average absorption over 95% at wavelengths ranging from 200 nm to 900 nm. Besides, owing to the ultrathin thickness and symmetrical topology of this device, it exhibits great angular tolerance up to 60° independent of the incident polarizations. Excellent thermal stability is also demonstrated at high operation temperatures. The physical origin of the ultra-broadband characteristics is mainly based on diffraction/interference engineering at short wavelengths and the anti-reflection effect at long wavelengths. We believe that such a device may find potential applications ranging from photodetection and photothermal energy conversion to ultraviolet protection and thermophotovoltaics.

  17. Direct-to-diffuse UV Solar Irradiance Ratio for a UV rotating Shadowband Spectroradiometer and a UV Multi-filter Rotating Shadowband Radiometer

    NASA Astrophysics Data System (ADS)

    Lantz, K.; Kiedron, P.; Petropavlovskikh, I.; Michalsky, J.; Slusser, J.

    2008-12-01

    . Two spectroradiometers reside that measure direct and diffuse UV solar irradiance are located at the Table Mountain Test Facility, 8 km north of Boulder, CO. The UV- Rotating Shadowband Spectrograph (UV-RSS) measures diffuse and direct solar irradiance from 290 - 400 nm. The UV Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR) measures diffuse and direct solar irradiance in seven 2-nm wide bands, i.e. 300, 305, 311, 317, 325, and 368 nm. The purpose of the work is to compare radiative transfer model calculations (TUV) with the results from the UV-Rotating Shadowband Spectroradiometer (UV-RSS) and the UV-MFRSR to estimate direct-to-diffuse solar irradiance ratios (DDR) that are used to evaluate the possibility of retrieving aerosol single scattering albedo (SSA) under a variety of atmospheric conditions: large and small aerosol loading, large and small surface albedo. For the radiative transfer calculations, total ozone measurements are obtained from a collocated Brewer spectrophotometer.

  18. Repression of Growth Regulating Factors by the MicroRNA396 Inhibits Cell Proliferation by UV-B Radiation in Arabidopsis Leaves[C][W

    PubMed Central

    Casadevall, Romina; Rodriguez, Ramiro E.; Debernardi, Juan M.; Palatnik, Javier F.; Casati, Paula

    2013-01-01

    Because of their sessile lifestyle, plants are continuously exposed to solar UV-B radiation. Inhibition of leaf growth is one of the most consistent responses of plants upon exposure to UV-B radiation. In this work, we investigated the role of GROWTH-REGULATING FACTORs (GRFs) and of microRNA miR396 in UV-B–mediated inhibition of leaf growth in Arabidopsis thaliana plants. We demonstrate that miRNA396 is upregulated by UV-B radiation in proliferating tissues and that this induction is correlated with a decrease in GRF1, GRF2, and GRF3 transcripts. Induction of miR396 results in inhibition of cell proliferation, and this outcome is independent of the UV-B photoreceptor UV resistance locus 8, as well as ATM AND RAD3–RELATED and the mitogen-activated protein kinase MPK6, but is dependent on MPK3. Transgenic plants expressing an artificial target mimic directed against miR396 (MIM396) with a decrease in the endogenous microRNA activity or plants expressing miR396-resistant copies of several GRFs are less sensitive to this inhibition. Consequently, at intensities that can induce DNA damage in Arabidopsis plants, UV-B radiation limits leaf growth by inhibiting cell division in proliferating tissues, a process mediated by miR396 and GRFs. PMID:24076976

  19. Solar UV-B radiation and ethylene play a key role in modulating effective defenses against Anticarsia gemmatalis larvae in field-grown soybean.

    PubMed

    Dillon, Francisco M; Tejedor, M Daniela; Ilina, Natalia; Chludil, Hugo D; Mithöfer, Axel; Pagano, Eduardo A; Zavala, Jorge A

    2018-02-01

    Solar UV-B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV-B mediated increment of plant resistance are unknown in crops species, such as soybean. Here, we studied defense-related responses in undamaged and Anticarsia gemmatalis larvae-damaged leaves of two soybean cultivars grown under attenuated or full solar UV-B radiation. We determined changes in jasmonates, ethylene (ET), salicylic acid, trypsin protease inhibitor activity, flavonoids, and mRNA expression of genes related with defenses. ET emission induced by Anticarsia gemmatalis damage was synergistically increased in plants grown under solar UV-B radiation and was positively correlated with malonyl genistin concentration, trypsin proteinase inhibitor activity and expression of IFS2, and the pathogenesis protein PR2, while was negatively correlated with leaf consumption. The precursor of ET, aminocyclopropane-carboxylic acid, applied exogenously to soybean was sufficient to strongly induce leaf isoflavonoids. Our results showed that in field-grown soybean isoflavonoids were regulated by both herbivory and solar UV-B inducible ET, whereas flavonols were regulated by solar UV-B radiation only and not by herbivory or ET. Our study suggests that, although ET can modulate UV-B-mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids, are regulated by ET alone. © 2017 John Wiley & Sons Ltd.

  20. Ultraviolet absorbance as a proxy for total dissolved mercury in streams

    USGS Publications Warehouse

    Dittman, J.A.; Shanley, J.B.; Driscoll, C.T.; Aiken, G.R.; Chalmers, A.T.; Towse, J.E.

    2009-01-01

    Stream water samples were collected over a range of hydrologic and seasonal conditions at three forested watersheds in the northeastern USA. Samples were analyzed for dissolved total mercury (THgd), DOC concentration and DOC composition, and UV254 absorbance across the three sites over different seasons and flow conditions. Pooling data from all sites, we found a strong positive correlation of THgd to DOC (r2 = 0.87), but progressively stronger correlations of THgd with the hydrophobic acid fraction (HPOA) of DOC (r2 = 0.91) and with UV254 absorbance (r2 = 0.92). The strength of the UV254 absorbance-THgd relationship suggests that optical properties associated with dissolved organic matter may be excellent proxies for THgd concentration in these streams. Ease of sample collection and analysis, the potential application of in-situ optical sensors, and the possibility for intensive monitoring over the hydrograph make this an effective, inexpensive approach to estimate THgd flux in drainage waters. ?? 2009 Elsevier Ltd.

  1. Analyzing Exonuclease-Induced Hyperchromicity by Uv Spectroscopy: An Undergraduate Biochemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Ackerman, Megan M.; Ricciardi, Christopher; Weiss, David; Chant, Alan; Kraemer-Chant, Christina M.

    2016-01-01

    An undergraduate biochemistry laboratory experiment is described that utilizes free online bioinformatics tools along with readily available exonucleases to study the effects of base stacking and hydrogen bonding on the UV absorbance of DNA samples. UV absorbance of double-stranded DNA at the ?[subscript max] is decreased when the DNA bases are…

  2. Phenol-Oxidizing Peroxidases Contribute to the Protection of Plants from Ultraviolet Radiation Stress1

    PubMed Central

    Jansen, Marcel A.K.; van den Noort, Ria E.; Tan, M.Y. Adillah; Prinsen, Els; Lagrimini, L. Mark; Thorneley, Roger N.F.

    2001-01-01

    We have studied the mechanism of UV protection in two duckweed species (Lemnaceae) by exploiting the UV sensitivity of photosystem II as an in situ sensor for radiation stress. A UV-tolerant Spirodela punctata G.F.W. Meyer ecotype had significantly higher indole-3-acetic acid (IAA) levels than a UV-sensitive ecotype. Parallel work on Lemna gibba mutants suggested that UV tolerance is linked to IAA degradation rather than to levels of free or conjugated IAA. This linkage is consistent with a role for class III phenolic peroxidases, which have been implicated both in the degradation of IAA and the cross-linking of various UV-absorbing phenolics. Biochemical analysis revealed increased activity of a specific peroxidase isozyme in both UV-tolerant duckweed lines. The hypothesis that peroxidases play a role in UV protection was tested in a direct manner using genetically modified tobacco (Nicotiana sylvestris). It was found that increased activity of the anionic peroxidase correlated with increased tolerance to UV radiation as well as decreased levels of free auxin. We conclude that phenol-oxidizing peroxidases concurrently contribute to UV protection as well as the control of leaf and plant architecture. PMID:11457952

  3. Influence of UV and Gamma radiations on the induced birefringence of stretched poly(vinyl) alcohol foils

    NASA Astrophysics Data System (ADS)

    Nechifor, Cristina-Delia; Zelinschi, Carmen Beatrice; Dorohoi, Dana-Ortansa

    2014-03-01

    The aim of our paper is to evidence the influence of Gamma and UV radiations on the induced birefringence of poly(vinyl alcohol) stretched foils. Thin foils of PVA were prepared and dried without modifying their surfaces. The polymeric foils were irradiated from 15 min to 6 h using UV and Gamma radiations. The induced by stretching under heating birefringence of PVA films was measured at λ = 589.3 nm with a Babinet Compensator. Physico-chemical processes (photo stabilization, photo degradation, oxidation) induced by irradiation of polymer matrix influence both the stretching degree and the anisotropy of etired foils. An increase of birefringence versus the stretching ratio of the PVA foils was evidenced for all studied samples. The dependence of the birefringence on the exposure time, stretching ratio and nature of radiation was also confirmed.

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

    PubMed

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

    2017-01-01

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

  5. Comparison of the effect of UV laser radiation and of a radiomimetic substance on chromatin

    NASA Astrophysics Data System (ADS)

    Radulescu, Irina; Radu, Liliana; Serbanescu, Ruxandra; Nelea, V. D.; Martin, C.; Mihailescu, Ion N.

    1998-07-01

    The damages of the complex of deoxyribonucleic acid (DNA) and proteins from chromatin, produced by the UV laser radiation and/or by treatment with a radiomimetic substance, bleomycin, were compared. The laser radiation and bleomycin effects on chromatin structure were determined by the static and dynamic fluorimetry of chromatin complexes with the DNA specific ligand-- proflavine and by the analysis of tryptophan chromatin intrinsic fluorescence. Time resolved spectroscopy is a sensitive technique which allows to determine the excited state lifetimes of chromatin--proflavine complexes. Also, the percentage contributions to the fluorescence of proflavine, bound and unbound to chromatin DNA, were evaluated. The damages produced by the UV laser radiation on chromatin are similar with those of radiomimetic substance action and consists in DNA and proteins destruction. The DNA damage degree has been determined. The obtained results may constitute some indications in the laser utilization in radiochimiotherapy.

  6. Bioconvertible vitamin antioxidants improve sunscreen photoprotection against UV-induced reactive oxygen species.

    PubMed

    Hanson, Kerry M; Clegg, Robert M

    2003-01-01

    The ability of sunscreens and antioxidants to deactivate highly destructive reactive oxygen species in human skin has remained inconclusive. Two-photon fluorescence imaging microscopy was used to determine the effect of sunscreen/antioxidant combinations upon UV-induced ROS generation in ex vivo human skin. A sunscreen combination containing octylmethoxycinnamate (Parsol MCX) and avobenzone (Parsol 1789) at SPF 8 and SPF 15 was tested for its ability to prevent UV radiation from generating ROS in the viable epidermal strata of ex vivo human skin. A UV dose equivalent to two hours of North American solar UV was used to irradiate the skin. Each sunscreen reduced the amount of ROS induced in the viable strata by a value consistent with the SPF level. UV photons that were not absorbed/scattered by the sunscreen formulations generated ROS within the viable epidermal layers. The addition of the bioconvertible antioxidants vitamin E acetate and sodium ascorbyl phosphate (STAY-C 50) improves photoprotection by converting to vitamins E and C, respectively, within the skin. The bioconversion forms an antioxidant reservoir that deactivates the ROS generated (within the strata granulosum, spinosum, and basale) by the UV photons that the sunscreens do not block in the stratum corneum.

  7. AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sun, K. X.

    2011-05-31

    This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.

  8. ROS and calcium signaling mediated pathways involved in stress responses of the marine microalgae Dunaliella salina to enhanced UV-B radiation.

    PubMed

    Zhang, Xinxin; Tang, Xuexi; Wang, Ming; Zhang, Wei; Zhou, Bin; Wang, You

    2017-08-01

    UV-B ray has been addressed to trigger common metabolic responses on marine microalgae, however, the upstream events responsible for these changes in marine microalgae are poorly understood. In the present study, a species of marine green microalgae Dunaliella salina was exposed to a series of enhanced UV-B radiation ranging from 0.25 to 1.00 KJ·m -2 per day. The role of ROS and calcium signaling in the D. salina responses to UV-B was discussed. Results showed that enhanced UV-B radiation markedly decreased the cell density in a dose-dependent manner, but the contents of protein and glycerol that were essential for cell growth increased. It suggested that it was cell division instead of cell growth that UV-B exerted negative effects on. The subcellular damages on nuclei and plasmalemma further evidenced the hypothesis. The nutrient absorption was affected with UV-B exposure, and the inhibition on PO 4 3- uptake was more serious compared to NO 3 - uptake. UV-B radiation promoted reactive oxygen species (ROS) formation and thiobarbituric acid reactive substances (TBARS) contents, decreased the redox status and altered the antioxidant enzyme activities. The addition of the ROS scavenger and the glutathione biosynthesis precursor N-acetyl-l-cysteine (NAC) alleviated the stress degree, implying ROS-mediated pathway was involved in the stress response to UV-B radiation. Transient increase in Ca 2+ -ATPase was triggered simultaneously with UV-B exposure. Meanwhile, the addition of an intracellular free calcium chelator aggravated the damage of cell division, but exogenous calcium and ion channel blocker applications did not, inferring that endogenously initiated calcium signaling played roles in response to UV-B. Cross-talk analysis showed a relatively clear relationship between ROS inhibition and Ca 2+ -ATPase suppression, and a relation between Ca 2+ inhibition and GPx activity change was also observed. It was thus presumed that ROS-coupled calcium signaling via the

  9. Study of the anticorrelations between ozone and UV-B radiation using linear and exponential fits in Southern Brazil

    NASA Astrophysics Data System (ADS)

    Guarnieri, R.; Padilha, L.; Guarnieri, F.; Echer, E.; Makita, K.; Pinheiro, D.; Schuch, A.; Boeira, L.; Schuch, N.

    Ultraviolet radiation type B (UV-B 280-315nm) is well known by its damage to life on Earth, including the possibility of causing skin cancer in humans. However, the atmo- spheric ozone has absorption bands in this spectral radiation, reducing its incidence on Earth's surface. Therefore, the ozone amount is one of the parameters, besides clouds, aerosols, solar zenith angles, altitude, albedo, that determine the UV-B radia- tion intensity reaching the Earth's surface. The total ozone column, in Dobson Units, determined by TOMS spectrometer on board of a NASA satellite, and UV-B radiation measurements obtained by a UV-B radiometer model MS-210W (Eko Instruments) were correlated. The measurements were obtained at the Observatório Espacial do Sul - Instituto Nacional de Pesquisas Espaciais (OES/CRSPE/INPE-MCT) coordinates: Lat. 29.44oS, Long. 53.82oW. The correlations were made using UV-B measurements in fixed solar zenith angles and only days with clear sky were selected in a period from July 1999 to December 2001. Moreover, the mathematic behavior of correlation in dif- ferent angles was observed, and correlation coefficients were determined by linear and first order exponential fits. In both fits, high correlation coefficients values were ob- tained, and the difference between linear and exponential fit can be considered small.

  10. A UV-B-specific signaling component orchestrates plant UV protection

    PubMed Central

    Brown, Bobby A.; Cloix, Catherine; Jiang, Guang Huai; Kaiserli, Eirini; Herzyk, Pawel; Kliebenstein, Daniel J.; Jenkins, Gareth I.

    2005-01-01

    UV-B radiation in sunlight has diverse effects on humans, animals, plants, and microorganisms. UV-B can cause damage to molecules and cells, and consequently organisms need to protect against and repair UV damage to survive in sunlight. In plants, low nondamaging levels of UV-B stimulate transcription of genes involved in UV-protective responses. However, remarkably little is known about the underlying mechanisms of UV-B perception and signal transduction. Here we report that Arabidopsis UV RESISTANCE LOCUS 8 (UVR8) is a UV-B-specific signaling component that orchestrates expression of a range of genes with vital UV-protective functions. Moreover, we show that UVR8 regulates expression of the transcription factor HY5 specifically when the plant is exposed to UV-B. We demonstrate that HY5 is a key effector of the UVR8 pathway, and that it is required for survival under UV-B radiation. UVR8 has sequence similarity to the eukaryotic guanine nucleotide exchange factor RCC1, but we found that it has little exchange activity. However, UVR8, like RCC1, is located principally in the nucleus and associates with chromatin via histones. Chromatin immunoprecipitation showed that UVR8 associates with chromatin in the HY5 promoter region, providing a mechanistic basis for its involvement in regulating transcription. We conclude that UVR8 defines a UV-B-specific signaling pathway in plants that orchestrates the protective gene expression responses to UV-B required for plant survival in sunlight. PMID:16330762

  11. AMBIENT SOLAR UV RADIATION CAUSES MORTALITY IN LARVAE OF THREE SPECIES OF RANA

    EPA Science Inventory

    Recent reports concerning the lethal effects of solar ultraviolet-B (UV-B) radiation on amphibians suggest that this stressor has the potential to impact some amphibian populations. In this study embryos and larvae of three anuran species, Rana pipiens, R. clamitans, and R. septe...

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

    USDA-ARS?s Scientific Manuscript database

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

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

    NASA Astrophysics Data System (ADS)

    Mendez, Y.; Vives, M.

    2017-07-01

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

  14. Near-Field Cosmology with Low-Mass Galaxies: Constraining the Escape of Radiation from the UV-slopes of Local Galaxies

    NASA Astrophysics Data System (ADS)

    Venkatesan, Aparna; Rosenberg, Jessica L.; Salzer, John Joseph; Gronke, Max; Cannon, John M.; Miller, Christopher J.; Dijkstra, Mark

    2018-06-01

    Low-mass galaxies are thought to play a large role in reionizing the Universe at redshifts, z > 6. However, due to limited UV data on low-mass galaxies, the models used to estimate the escape of radiation are poorly constrained. Using theoretical models of radiation transport in dusty galaxies with clumpy gas media, we translate measurements of the UV slopes of a sample of low-mass low-z KISSR galaxies to their escape fraction values in Ly-alpha radiation, fesc (LyA), and in the Ly-continuum, fesc (LyC). These low-mass starforming systems have potentially steep UV slopes, and could provide a much-needed relation between easily measured spectral properties such as UV slope or LyA line properties, and the escape of LyA/LyC radiation. Such a relation could advance studies of primordial star clusters and the underlying physical conditions characterizing early galaxies, one of the target observation goals of the soon to-be-launched James Webb Space Telescope. This work was supported by the University of San Francisco Faculty Development Fund, and NSF grant AST-1637339. We thank the Aspen Center for Physics, where some of this work was conducted, and which is supported by National Science Foundation grant PHY-1607611.

  15. Effect of UV-A radiation as an environmental stress on the development, longevity, and reproduction of the oriental armyworm, Mythimna separata (Lepidoptera: Noctuidae).

    PubMed

    Ali, Arif; Rashid, Muhammad Adnan; Huang, Qiu Ying; Lei, Chao-Liang

    2016-09-01

    The ultraviolet light (UV-A) range of 320-400 nm is widely used as light trap for insect pests. Present investigation was aimed to determine the effect of UV light-A radiation on development, adult longevity, reproduction, and development of F1 generation of Mythimna separata. Our results revealed that the mortality of the second instar larvae was higher than the third and fourth instar larvae after UV-A radiation. As the time of UV-A irradiation for pupae prolonged, the rate of adult emergence reduced. Along with the extension of radiation time decreased the longevity of adult females and males. However, the radiation exposure of 1 and 4 h/day increased fecundity of female adults, and a significant difference was observed in a 1 h/day group. The oviposition rates of female adults in all the treatments were significantly higher than the control. In addition, UV-A radiation treatments resulted in declined cumulative survival of F1 immature stages (eggs, larvae, and pupae). After exposure time of 4 and 7 h/day, the developmental periods of F1 larvae increased significantly, but no significant effects on F1 pupal period were recorded.

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

    PubMed

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

    2016-10-01

    The impact of increased artificial UV-B radiation on photosynthetic performance, antioxidant and SOD activities and molecular antioxidant metabolism responses in leaves of two highbush blueberry (Vaccinium corymbosum L. cv. Brigitta and Bluegold) genotypes was studied. Plants were grown in a solid substrate and exposed to 0, 0.07, 0.12 and 0.19 W m(-2) of biologically-effective UV-B irradiance for 0-72 h. Our findings show that net photosynthesis (Pn) decreased significantly in Bluegold, accompanied by a reduction in the effective quantum yield (ФPSII) and electron transport rate (ETR), especially at the highest UV-B irradiation. On the other hand, Brigitta showed a better photosynthetic performance, as well as a clear increment in the antioxidant activity response that could be associated with increased superoxide dismutase activity (SOD) in the early hours of induced UV-B stress in all treatments. At the molecular level, the expression of the three antioxidant genes evaluated in both genotypes had a similar tendency. However, ascorbate peroxidase (APX) expression was significantly increased (6-fold) in Bluegold compared to Brigitta. Thus, the reduction of Pn concomitant with a lower photochemical performance and a reduced response of antioxidant metabolism suggest that the Bluegold genotype is more sensitive to UV-B radiation, while Brigitta appears to tolerate better moderate UV-B irradiance in a short-term experiment. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Use of a heated graphite scrubber as a means of reducing interferences in UV-absorbance measurements of atmospheric ozone

    NASA Astrophysics Data System (ADS)

    Turnipseed, Andrew A.; Andersen, Peter C.; Williford, Craig J.; Ennis, Christine A.; Birks, John W.

    2017-06-01

    A new solid-phase scrubber for use in conventional ozone (O3) photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100-130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic compounds (VOCs) compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal equivalent method (FEM) ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber's ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm), the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH), volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the United States (U.S.) Clean Air Act or for use in VOC-rich environments such as in smog chambers and monitoring indoor air quality.

  18. In situ measurement of VUV/UV radiation from low-pressure microwave-produced plasma in Ar/O2 gas mixtures

    NASA Astrophysics Data System (ADS)

    Iglesias, E. J.; Mitschker, F.; Fiebrandt, M.; Bibinov, N.; Awakowicz, P.

    2017-08-01

    Ultraviolet (UV) and vacuum ultraviolet (VUV) spectral irradiance is determined in low-pressure microwave-produced plasma, which is regularly used for polymer surface treatment. The re-emitted fluorescence in the UV/VIS spectral range from a sodium salicylate layer is measured. This fluorescence is related to VUV/UV radiation in different spectral bands based on cut-off filters. The background produced by direct emitted radiation in the fluorescence spectral region is quantified using a specific background filter, thus enabling the use of the whole fluorescence spectral range. A novel procedure is applied to determine the absolute value of the VUV/UV irradiance on a substrate. For that, an independent measurement of the absolute spectral emissivity of the plasma in the UV is performed. The measured irradiances on a substrate from a 25 Pa Ar/O2-produced plasma are in the range of 1015-1016 (photon~ s-1 cm-2). These values include the contribution from impurities present in the discharge.

  19. Induction of wound-periderm-like tissue in Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) leaves as a defence response to high UV-B radiation levels

    PubMed Central

    Nascimento, Luana Beatriz dos Santos; Moreira, Nattacha dos Santos; Leal-Costa, Marcos Vinícius; Costa, Sônia Soares; Tavares, Eliana Schwartz

    2015-01-01

    Background and Aims UV-B radiation can be stressful for plants and cause morphological and biochemical changes. Kalanchoe pinnata is a CAM leaf-succulent species distributed in hot and dry regions, and is rich in flavonoids, which are considered to be protective against UV-B radiation. This study aims to verify if K. pinnata has morphological or anatomical responses as a strategy in response to high UV-B levels. Methods Kalanchoe pinnata plants of the same age were grown under white light (control) or white light plus supplemental UV-B radiation (5 h d–1). The plants were treated with the same photoperiod, photosynthetically active radiation, temperature and daily watering system. Fragments of the middle third of the leaf blade and petiole were dehydrated and then embedded in historesin and sectioned in a rotary microtome. Sections were stained with toluidine blue O and mounted in Entellan®. Microchemical analyses by optical microscopy were performed on fresh material with Sudan III, Sudan IV and phloroglucinol, and analysed using fluorescence microscopy. Key Results Supplemental UV-B radiation caused leaf curling and the formation of brown areas on the leaves. These brown areas developed into a protective tissue on the adaxial side of the leaf, but only in directly exposed regions. Anatomically, this protective tissue was similar to a wound-periderm, with outer layer cell walls impregnated with suberin and lignin. Conclusions This is the first report of wound-periderm formation in leaves in response to UV-B radiation. This protective tissue could be important for the survival of the species in desert regions under high UV-B stress conditions. PMID:26346722

  20. A new approach to correct for absorbing aerosols in OMI UV

    NASA Astrophysics Data System (ADS)

    Arola, A.; Kazadzis, S.; Lindfors, A.; Krotkov, N.; Kujanpää, J.; Tamminen, J.; Bais, A.; di Sarra, A.; Villaplana, J. M.; Brogniez, C.; Siani, A. M.; Janouch, M.; Weihs, P.; Webb, A.; Koskela, T.; Kouremeti, N.; Meloni, D.; Buchard, V.; Auriol, F.; Ialongo, I.; Staneck, M.; Simic, S.; Smedley, A.; Kinne, S.

    2009-11-01

    Several validation studies of surface UV irradiance based on the Ozone Monitoring Instrument (OMI) satellite data have shown a high correlation with ground-based measurements but a positive bias in many locations. The main part of the bias can be attributed to the boundary layer aerosol absorption that is not accounted for in the current satellite UV algorithms. To correct for this shortfall, a post-correction procedure was applied, based on global climatological fields of aerosol absorption optical depth. These fields were obtained by using global aerosol optical depth and aerosol single scattering albedo data assembled by combining global aerosol model data and ground-based aerosol measurements from AERONET. The resulting improvements in the satellite-based surface UV irradiance were evaluated by comparing satellite and ground-based spectral irradiances at various European UV monitoring sites. The results generally showed a significantly reduced bias by 5-20%, a lower variability, and an unchanged, high correlation coefficient.

  1. Development of a low cost UV index datalogger and comparison between UV index sensors

    NASA Astrophysics Data System (ADS)

    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.

  2. Multi-target determination of organic ultraviolet absorbents in organism tissues by ultrasonic assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Peng, Xianzhi; Jin, Jiabin; Wang, Chunwei; Ou, Weihui; Tang, Caiming

    2015-03-06

    A sensitive and reliable method was developed for multi-target determination of 13 most widely used organic ultraviolet (UV) absorbents (including UV filters and UV stabilizers) in aquatic organism tissues. The organic UV absorbents were extracted using ultrasonic-assisted extraction, purified via gel permeation chromatography coupled with silica gel column chromatography, and determined by ultra-high performance liquid chromatography-tandem mass spectrometry. Recoveries of the UV absorbents from organism tissues mostly ranged from 70% to 120% from fish filet with satisfactory reproducibility. Method quantification limits were 0.003-1.0ngg(-1) dry weight (dw) except for 2-ethylhexyl 4-methoxycinnamate. This method has been applied to analysis of the UV absorbents in wild and farmed aquatic organisms collected from the Pearl River Estuary, South China. 2-Hydroxy-4-methoxybenzophenone and UV-P were frequently detected in both wild and farmed marine organisms at low ngg(-1)dw. 3-(4-Methylbenzylidene)camphor and most of the benzotriazole UV stabilizers were also frequently detected in maricultured fish. Octocrylene and 2-ethylhexyl 4-methoxycinnamate were not detected in any sample. This work lays basis for in-depth study about bioaccumulation and biomagnification of the UV absorbents in marine environment. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    PubMed

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

    2015-05-01

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

  4. UV laser radiation alters the embryonic protein profile of adrenal-kidney-gonadal complex and gonadal differentiation in the lizard, Calotes Versicolor.

    PubMed

    Khodnapur, Bharati S; Inamdar, Laxmi S; Nindi, Robertraj S; Math, Shivkumar A; Mulimani, B G; Inamdar, Sanjeev R

    2015-02-01

    To examine the impact of ultraviolet (UV) laser radiation on the embryos of Calotes versicolor in terms of its effects on the protein profile of the adrenal-kidney-gonadal complex (AKG), sex determination and differentiation, embryonic development and hatching synchrony. The eggs of C. versicolor, during thermo-sensitive period (TSP), were exposed to third harmonic laser pulses at 355 nm from a Q-switched Nd:YAG laser for 180 sec. Subsequent to the exposure they were incubated at the male-producing temperature (MPT) of 25.5 ± 0.5°C. The AKG of hatchlings was subjected to protein analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and to histology. The UV laser radiation altered the expression of the protein banding pattern in the AKG complex of hatchlings and it also affected the gonadal sex differentiation. SDS-PAGE of AKG of one-day-old hatchlings revealed a total of nine protein bands in the control group whereas UV laser irradiated hatchlings expressed a total of seven protein bands only one of which had the same Rf as a control band. The UV laser treated hatchlings have an ovotestes kind of gonad exhibiting a tendency towards femaleness instead of the typical testes. It is inferred that 355 nm UV laser radiation during TSP induces changes in the expression of proteins as well as their secretions. UV laser radiation had an impact on the gonadal differentiation pathway but no morphological anomalies were noticed.

  5. Study of noninvasive detection of latent fingerprints using UV laser

    NASA Astrophysics Data System (ADS)

    Li, Hong-xia; Cao, Jing; Niu, Jie-qing; Huang, Yun-gang; Mao, Lin-jie; Chen, Jing-rong

    2011-06-01

    Latent fingerprints present a considerable challenge in forensics, and noninvasive procedure that captures a digital image of the latent fingerprints is significant in the field of criminal investigation. The capability of photography technologies using 266nm UV Nd:YAG solid state laser as excitation light source to provide detailed images of unprocessed latent fingerprints is demonstrated. Unprocessed latent fingerprints were developed on various non-absorbent and absorbing substrates. According to the special absorption, reflection, scattering and fluorescence characterization of the various residues in fingerprints (fatty acid ester, protein, and carbosylic acid salts etc) to the UV light to weaken or eliminate the background disturbance and increase the brightness contrast of fingerprints with the background, and using 266nm UV laser as excitation light source, fresh and old latent fingerprints on the surface of four types of non-absorbent objects as magazine cover, glass, back of cellphone, wood desktop paintwork and two types of absorbing objects as manila envelope, notebook paper were noninvasive detected and appeared through reflection photography and fluorescence photography technologies, and the results meet the fingerprint identification requirements in forensic science.

  6. Radiation absorbed dose to bladder walls from positron emitters in the bladder content.

    PubMed

    Powell, G F; Chen, C T

    1987-01-01

    A method to calculate absorbed doses at depths in the walls of a static spherical bladder from a positron emitter in the bladder content has been developed. The beta ray dose component is calculated for a spherical model by employing the solutions to the integration of Loevinger and Bochkarev point source functions over line segments and a line segment source array technique. The gamma ray dose is determined using the specific gamma ray constant. As an example, absorbed radiation doses to the bladder walls from F-18 in the bladder content are presented for static spherical bladder models having radii of 2.0 and 3.5 cm, respectively. Experiments with ultra-thin thermoluminescent dosimeters (TLD's) were performed to verify the results of the calculations. Good agreement between TLD measurements and calculations was obtained.

  7. Climate change and agricultural workers' health in Ecuador: occupational exposure to UV radiation and hot environments.

    PubMed

    Harari Arjona, Raul; Piñeiros, Jessika; Ayabaca, Marcelo; Harari Freire, Florencia

    2016-01-01

    Climate change is a global concern but little is known about its potential health effects in workers from non-industrialized countries. Ecuadorian workers from the coast (hot environments) and Andean region (elevated UV radiation) might be at particular risk of such effects. In the Andean region, measurements of UV index show maximum levels exceeding 11, a level considered being extreme according to the WHO. Also, an increased incidence of skin cancer was reported the last decennium, this being the second most common cancer type in men and women. In the coast, a high reported prevalence of kidney disease in agricultural workers is suggested to be related to exposure to hot temperatures. The scarce data available on occupational health in Ecuadorian agricultural workers raise the need for further investigation. Data worldwide shows an increasing prevalence of UV radiation- and heat stress-related illnesses in agricultural workers and urges the adoption of preventive measures.

  8. UV-responsive nano-sponge for oil absorption and desorption

    PubMed Central

    Kim, Do Hyun; Jung, Min Chan; Cho, So-Hye; Kim, Sang Hoon; Kim, Ho-Young; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-01-01

    Controlled surface wettability for oil has been intensively studied to remove industrial oil waste or oil spill pollution from seas or rivers. In particular, external stimuli-induced special wetting materials, such as photo-responsive TiO2, have attracted considerable attention for oil-water separation. In this study, a novel method is reported to fabricate a nano-sponge which is composed of hydrophobic hydrocarbon and hydrophilic TiO2 nanoparticles for oil absorption or desorption that are responsive to UV irradiation. The hydrocarbon in the nano-sponge could selectively absorb oil from water, whereas the absorbed oil is released into the water by TiO2 in response to UV irradiation. The nano-sponge functionalized porous polydimethylsiloxane released more than 98% of the absorbed crude oil with UV irradiation and air-bubbling. It could be continuously reused while maintaining a high absorption capacity and desorption efficiency without incurring secondary air or water pollution. This smart oil absorption/desorption methodology with excellent selectivity and recyclability with almost perfect removal of absorbed oil can be applied for oil-water separation, oil spill cleanup and reuse of spilled oil. PMID:26260470

  9. UV clothing and skin cancer.

    PubMed

    Tarbuk, Anita; Grancarić, Ana Marija; Situm, Mirna; Martinis, Mladen

    2010-04-01

    Skin cancer incidence in Croatia is steadily increasing in spite of public and governmental permanently measurements. It is clear that will soon become a major public health problem. The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet (UV) radiation. The future designers of UV protective materials should be able to block totally the ultraviolet radiation. The aim of this paper is to present results of measurements concerning UV protecting ability of garments and sun-screening textiles using transmission spectrophotometer Cary 50 Solarscreen (Varian) according to AS/NZS 4399:1996; to show that standard clothing materials are not always adequate to prevent effect of UV radiation to the human skin; and to suggest the possibilities for its improvement for this purpose.

  10. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation

    NASA Astrophysics Data System (ADS)

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice ( Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m-2 day-1) and elevated UV-B radiation (E, a 20 % higher dose of UV-B than the reference, 14.4 kJ m-2 day-1), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha-1), Si1 (sodium silicate, 100 kg SiO2 ha-1), Si2 (sodium silicate, 200 kg SiO2 ha-1), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha-1). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate ( Pn), intercellular carbon dioxide (CO2) concentration ( Ci), transpiration rate ( Tr), stomatal conductivity ( Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3 %, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9 %, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2 %, respectively, but decreased Tr by 1.9-10.8 %, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  11. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation.

    PubMed

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice (Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m(-2) day(-1)) and elevated UV-B radiation (E, a 20% higher dose of UV-B than the reference, 14.4 kJ m(-2) day(-1)), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha(-1)), Si1 (sodium silicate, 100 kg SiO2 ha(-1)), Si2 (sodium silicate, 200 kg SiO2 ha(-1)), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha(-1)). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate (Pn), intercellular carbon dioxide (CO2) concentration (Ci), transpiration rate (Tr), stomatal conductivity (Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3%, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9%, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2%, respectively, but decreased Tr by 1.9-10.8%, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  12. UV Induced Oxidation of Nitric Oxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde, F. (Inventor); Luecke, Dale E. (Inventor)

    2007-01-01

    Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated at least in part using in situ UV radiation sources. The sources of the oxidizing species include oxygen and/or hydrogen peroxide. The oxygen may be a component of the gaseous stream or added to the gaseous stream, preferably near a UV radiation source, and is converted to ozone by the UV irradiation. The hydrogen peroxide is decomposed through a combination of vaporization and UV irradiation. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50% by volume and increased in concentration in a continuous process preceding vaporization within the flow channel of the gaseous stream and in the presence of the UV radiation sources.

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

    PubMed

    Keller, B; Zölzer, F; Kiefer, J

    2004-01-01

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

  14. Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV-C radiation.

    PubMed

    Salma, Kloula Ben Ghorbal; Lobna, Maalej; Sana, Khefacha; Kalthoum, Chourabi; Imene, Ouzari; Abdelwaheb, Chatti

    2016-07-01

    It was well known that, UV-C irradiation increase considerably the reactive oxygen species (ROS) levels in eukaryotic and prokaryotic organisms. In the enzymatic ROS-scavenging pathways, superoxide dismutase (SOD), Catalase (CAT), and peroxidase (POX) were developed to deal with oxidative stress. In this study, we investigated the effects of UV-C radiations on antioxidant enzymes (catalase, superoxide dismutase, and peroxidases) expression in Pseudomonas aeruginosa. Catalase, superoxide dismutase, and peroxidases activities were determined spectrophotometrically. Isozymes of superoxide dismutase were revealed by native gel activity staining method. Lipid peroxidation was determined by measuring malondialdehyde formation. Our results showed that superoxide dismutase, catalase and peroxidase activities exhibited a gradual increase during the exposure time (30 min). However, the superoxide dismutase activity was maximized at 15 min. Native gel activity staining assays showed the presence of three superoxide dismutase isozymes. The iron-cofactored isoform activity was altered after exposure to UV-C stress. These finding suggest that catalase and peroxidase enzymes have the same importance toward UV-C rays at shorter and longer exposure times and this may confer additional protection to superoxide dismutase from damage caused by lipid peroxidation. Moreover, our data demonstrate the significant role of the antioxidant system in the resistance of this important human pathogen. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Experimental Evolution of UV-C Radiation Tolerance: Emergence of Adaptive and Non-Adaptive Traits in Escherichia coli Under Differing Flux Regimes

    NASA Astrophysics Data System (ADS)

    Moffet, A.; Okansinski, A.; Sloan, C.; Grace, J. M.; Paulino-Lima, I. G.; Gentry, D.; Rothschild, L. J.; Camps, M.

    2014-12-01

    High-energy ultraviolet (UV-C) radiation is a significant challenge to life in environments such as high altitude areas, the early Earth, the Martian surface, and space. As UV-C exposure is both a selection pressure and a mutagen, adaptation dynamics in such environments include a high rate of change in both tolerance-related and non-tolerance-related genes, as well changes in linkages between the resulting traits. Determining the relationship between the intensity and duration of the UV-C exposure, mutation rate, and emergence of UV-C resistance will inform our understanding of both the emergence of radiation-related extremophily in natural environments and the optimal strategies for generating artificial extremophiles. In this study, we iteratively exposed an Escherichia colistrain to UV-C radiation of two different fluxes, 3.3 J/m^2/s for 6 seconds and 0.5 J/m^2/s for 40 seconds, with the same overall fluence of 20 J/m^2. After each iteration, cells from each exposure regime were assayed for increased UV-C tolerance as an adaptive trait. The exposed cells carried a plasmid bearing a TEM beta-lactamase gene, which in the absence of antibiotic treatment is a neutral reporter for mutagenesis. Sequencing of this gene allowed us to determine the baseline mutation frequency for each flux. As an additional readout for adaptation, the presence of extended-spectrum beta-lactamase mutations was tested by plating UV-exposed cultures in cefotaxime plates. We observed an increase of approximately one-million-fold in UV-C tolerance over seven iterations; no significant difference between the two fluxes was found. Future work will focus on identifying the genomic changes responsible for the change in UV-C tolerance; determining the mechanisms of the emerged UV-C tolerance; and performing competition experiments between the iteration strains to quantify fitness tradeoffs resulting from UV-C adaptation.

  16. Induction of wound-periderm-like tissue in Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) leaves as a defence response to high UV-B radiation levels.

    PubMed

    Nascimento, Luana Beatriz dos Santos; Moreira, Nattacha dos Santos; Leal-Costa, Marcos Vinícius; Costa, Sônia Soares; Tavares, Eliana Schwartz

    2015-10-01

    UV-B radiation can be stressful for plants and cause morphological and biochemical changes. Kalanchoe pinnata is a CAM leaf-succulent species distributed in hot and dry regions, and is rich in flavonoids, which are considered to be protective against UV-B radiation. This study aims to verify if K. pinnata has morphological or anatomical responses as a strategy in response to high UV-B levels. Kalanchoe pinnata plants of the same age were grown under white light (control) or white light plus supplemental UV-B radiation (5 h d(-1)). The plants were treated with the same photoperiod, photosynthetically active radiation, temperature and daily watering system. Fragments of the middle third of the leaf blade and petiole were dehydrated and then embedded in historesin and sectioned in a rotary microtome. Sections were stained with toluidine blue O and mounted in Entellan®. Microchemical analyses by optical microscopy were performed on fresh material with Sudan III, Sudan IV and phloroglucinol, and analysed using fluorescence microscopy. Supplemental UV-B radiation caused leaf curling and the formation of brown areas on the leaves. These brown areas developed into a protective tissue on the adaxial side of the leaf, but only in directly exposed regions. Anatomically, this protective tissue was similar to a wound-periderm, with outer layer cell walls impregnated with suberin and lignin. This is the first report of wound-periderm formation in leaves in response to UV-B radiation. This protective tissue could be important for the survival of the species in desert regions under high UV-B stress conditions. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Solar UV Radiation and the Origin of Life on Earth

    NASA Technical Reports Server (NTRS)

    Heap, S. R.; Gaidos, E.; Hubeny, I.; Lanz, T. M.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

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

  18. Improving UV protection by clothing--recent developments.

    PubMed

    Osterwalder, Uli; Rohwer, Hauke

    2002-01-01

    The assessment of UV transmittance of clothing and the determination of the UV protection factor (UPF) are now well established and the influencing factors such as type of fiber, color, and fabric construction are known. Quick and reliable instruments to measure UV transmittance are crucial. Besides expensive scientific laboratory instruments, a low-cost UV meter is now available for this purpose. The questions arise as to what can be done about a given garment and whether there are ways to improve textiles by the consumer. The many opportunities to improve UV protection of clothing along the textile chain of manufacturing are discussed. The latest possibility for improving the UV-protective properties of clothing is now available at the fabric care stage in every household. A UV absorber can be brought into contact with a fabric during the wash or rinse cycle of a laundry operation. The high UV transmittance of 30% of a thin, bleached cotton swatch in the dry state (UPF 3), can be reduced tenfold to about 3% (UPF >30) in ten washes cycles. This is more than the effect achieved by dyestuffs. The detergent should contain about 0.1-0.3% of the special UV absorber. The same effect can be achieved as early as after one wash cycle with a higher concentration provided by a special laundry additive. Yet another form of application is via rinse cycle fabric conditioner. To make these new types of improvement of fabrics visible the Skin Cancer Foundation now provides the possibility for laundry products to qualify for the "Seal of Recommendation".

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

    NASA Astrophysics Data System (ADS)

    Kocifaj, Miroslav; Solano Lamphar, Hector Antonio

    2013-09-01

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

  20. Effects of ultraviolet-B radiation on the growth, physiology and cannabinoid production of Cannabis sativa L

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lydon, J.

    The concentration of cannabinoids in Cannabis sativa L. is correlated with high ultraviolet-B (UV-B) radiation environments. ..delta../sup 9/-Tetrahydrocannabinolic acid and cannabidiolic acid, both major secondary products of C. sativa, absorb UV-B radiation and may function as solar screens. The object of this study was to test the effects of UV-B radiation on the physiology and cannabinoid production of C. sativa. Drug and fiber-type C. sativa were irradiated with three levels of UV-B radiation for 40 days in greenhouse experiments. Physiological measurements on leaf tissues were made by infra-red gas analysis. Drug and fiber-type control plants had similar CO/sub 2/ assimilationmore » rates from 26 to 32/sup 0/C. Drug-type control plant had higher dark respiration rates and stomatal conductances than fiber-type control plants. The concentration of ..delta../sup 9/-THC, but not of other cannabinoids) in both vegetative and reproductive tissues increased with UV-B dose in drug-type plants. None of the cannabinoids in fiber-type plants were affected by UV-B radiation. The increased level of ..delta../sup 9/-THC found in leaves after irradiation may account for the physiological and morphological insensitivity to UV-B radiation in the drug-type plants. However, fiber plants showed no comparable change in the level of cannabidoil (CBD). Resin stripped form fresh fiber-type floral tissue by sonication was spotted on filter paper and irradiated continuously for 7 days. Cannabidiol (CBD) gradually decreased when irradiated but ..delta../sup 9/-THC and cannabichromene did not.« less

  1. Visible emission in Sm3+ and Tb3+ doped phosphate glass excited by UV radiation

    NASA Astrophysics Data System (ADS)

    Zmojda, Jacek; Dorosz, Dominik; Kochanowicz, Marcin; Miluski, Piotr; Czajkowski, Karol; Ragin, Tomasz

    2013-10-01

    In the article analysis of UV absorption and visible fluorescence of Sm3+ and Tb3+ ions doped phosphate glass with molar composition: 65P2O5 + 8Al2O3 + 10BaO + 17(Na2O + MgO + ZnO) have been investigated. As a result of optical pumping fabricated glass with radiation from a deuterium lamp four luminescence bands were observed near to the wavelength of 600 nm for Sm3+ ions and 550 nm for Tb3+ ions. It was found that larger energy gap between laser and ground levels leads to the strongest emission in the visible range in terbium doped glasses than in glasses doped with samarium ions. Both fabricated glasses are characterized by the ability to selectively detect the radiation in the UV range.

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

    PubMed

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

    2014-11-01

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

  3. Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial.

    PubMed

    Castanedo-Cazares, Juan Pablo; Hernandez-Blanco, Diana; Carlos-Ortega, Blanca; Fuentes-Ahumada, Cornelia; Torres-Álvarez, Bertha

    2014-02-01

    Melasma is an acquired hyperpigmentation on sun-exposed areas. Multiple approaches are used to treat it, but all include broad ultraviolet (UV)-spectrum sunscreens. Visible light (VL) can induce pigmentary changes similar to those caused by UV radiation on darker-skinned patients. To assess the efficacy of sunscreen with broad-spectrum UV protection that contains iron oxide as a VL-absorbing pigment (UV-VL) compared with a regular UV-only broad-spectrum sunscreen for melasma patients exposed to intense solar conditions. Sixty-eight patients with melasma were randomized in two groups to receive either UV-VL sunscreen or UV-only sunscreen, both with sun protection factor ≥ 50, over 8 weeks. All patients received 4% hydroquinone as a depigmenting treatment. At onset and at conclusion of the study, they were assessed by the Melasma Activity and Severity Index (MASI; a subjective scale), colorimetry (L*) and histological analysis of melanin. Sixty-one patients concluded the study. At 8 weeks, the UV-VL group showed 15%, 28% and 4% greater improvements than the UV-only group in MASI scores, colorimetric values and melanin assessments, respectively. UV-VL sunscreen enhances the depigmenting efficacy of hydroquinone compared with UV-only sunscreen in treatment of melasma. These findings suggest a role for VL in melasma pathogenesis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Scattered radiation doses absorbed by technicians at different distances from X-ray exposure: Experiments on prosthesis.

    PubMed

    Chiang, Hsien-Wen; Liu, Ya-Ling; Chen, Tou-Rong; Chen, Chun-Lon; Chiang, Hsien-Jen; Chao, Shin-Yu

    2015-01-01

    This work aimed to investigate the spatial distribution of scattered radiation doses induced by exposure to the portable X-ray, the C-arm machine, and to simulate the radiologist without a shield of lead clothing, radiation doses absorbed by medical staff at 2 m from the central exposure point. With the adoption of the Rando Phantom, several frequently X-rayed body parts were exposed to X-ray radiation, and the scattered radiation doses were measured by ionization chamber dosimeters at various angles from the patient. Assuming that the central point of the X-ray was located at the belly button, five detection points were distributed in the operation room at 1 m above the ground and 1-2 m from the central point horizontally. The radiation dose measured at point B was the lowest, and the scattered radiation dose absorbed by the prosthesis from the X-ray's vertical projection was 0.07 ±0.03 μGy, which was less than the background radiation levels. The Fluke biomedical model 660-5DE (400 cc) and 660-3DE (4 cc) ion chambers were used to detect air dose at a distance of approximately two meters from the central point. The AP projection radiation doses at point B was the lowest (0.07±0.03 μGy) and the radiation doses at point D was the highest (0.26±0.08 μGy) .Only taking the vertical projection into account, the radiation doses at point B was the lowest (0.52 μGy), and the radiation doses at point E was the highest (4 μGy).The PA projection radiation at point B was the lowest (0.36 μGy) and the radiation doses at point E was the highest(2.77 μGy), occupying 10-32% of the maximum doses. The maximum dose in five directions was nine times to the minimum dose. When the PX and the C-arm machine were used, the radiation doses at a distance of 2 m were attenuated to the background radiation level. The radiologist without a lead shield should stand at point B of patient's feet. Accordingly, teaching materials on radiation safety for radiological interns and clinical

  5. Influence of Transcutol CG on the skin accumulation and transdermal permeation of ultraviolet absorbers.

    PubMed

    Godwin, Donald A; Kim, Nae-Hwa; Felton, Linda A

    2002-01-01

    The objective of this study was to determine the influence of Transcutol CG concentration on the transdermal permeation and skin accumulation of two ultraviolet (UV) absorbers, 2-hydroxy-4-methoxybenzophenone (oxybenzone) and 2-octyl-4-methoxycinnamate (cinnamate). The concentration of the UV absorber was held constant at 6% (w/w) for all vehicle systems while the concentration of Transcutol CG was varied from 0 to 50% (w/w). Data showed that both UV absorbers exhibited increases in skin accumulation with increasing concentrations of Transcutol CG. Skin accumulation of oxybenzone was significantly (P<0.05) greater than that of cinnamate for all formulations investigated. Oxybenzone skin accumulation ranged from 22.9+/-2.8 microg/mg (0% Transcutol CG) to 80.8+/-27.2 microg/mg (50% Transcutol CG). Cinnamate skin accumulation ranged from 9.0+/-0.9 microg/mg to 39.8+/-12.2 microg/mg at 0 and 50% Transcutol CG, respectively. No significant differences were found in the transdermal permeation of oxybenzone or cinnamate for any of the formulations tested. The results of this study demonstrate that the inclusion of Transcutol CG in sunscreen formulations increases the skin accumulation of the UV absorbers oxybenzone and cinnamate without a concomitant increase in transdermal permeation.

  6. The influence of surface type on the absorbed radiation by a human under hot, dry conditions

    NASA Astrophysics Data System (ADS)

    Hardin, A. W.; Vanos, J. K.

    2018-01-01

    Given the predominant use of heat-retaining materials in urban areas, numerous studies have addressed the urban heat island mitigation potential of various "cool" options, such as vegetation and high-albedo surfaces. The influence of altered radiational properties of such surfaces affects not only the air temperature within a microclimate, but more importantly the interactions of long- and short-wave radiation fluxes with the human body. Minimal studies have assessed how cool surfaces affect thermal comfort via changes in absorbed radiation by a human ( R abs) using real-world, rather than modeled, urban field data. The purpose of the current study is to assess the changes in the absorbed radiation by a human—a critical component of human energy budget models—based on surface type on hot summer days (air temperatures > 38.5∘C). Field tests were conducted using a high-end microclimate station under predominantly clear sky conditions over ten surfaces with higher sky view factors in Lubbock, Texas. Three methods were used to measure and estimate R abs: a cylindrical radiation thermometer (CRT), a net radiometer, and a theoretical estimation model. Results over dry surfaces suggest that the use of high-albedo surfaces to reduce overall urban heat gain may not improve acute human thermal comfort in clear conditions due to increased reflected radiation. Further, the use of low-cost instrumentation, such as the CRT, shows potential in quantifying radiative heat loads within urban areas at temporal scales of 5-10 min or greater, yet further research is needed. Fine-scale radiative information in urban areas can aid in the decision-making process for urban heat mitigation using non-vegetated urban surfaces, with surface type choice is dependent on the need for short-term thermal comfort, or reducing cumulative heat gain to the urban fabric.

  7. Photodetector with absorbing region having resonant periodic absorption between reflectors

    DOEpatents

    Bryan, R.P.; Olbright, G.R.; Brennan, T.M.; Tsao, J.Y.

    1995-02-14

    A photodetector is disclosed that is responsive to a wavelength or wavelengths of interest which have heretofore been unrealized. The photodetector includes a resonant cavity structure bounded by first and second reflectors, the resonant cavity structure being resonant at the wavelength or wavelengths of interest for containing a plurality of standing waves therein. The photodetector further includes a radiation absorbing region disposed within the resonant cavity structure, the radiation absorbing region including a plurality of radiation absorbing layers spaced apart from one another by a distance substantially equal to a distance between antinodes of adjacent ones of the standing waves. Each of radiation absorbing layers is spatially positioned at a location of one of the antinodes of one of the standing waves such that radiation absorption is enhanced. The radiation absorbing layers may be either bulk layers or quantum wells includes a plurality of layers, each of which is comprised of a strained layer of InGaAs. Individual ones of the InGaAs layers are spaced apart from one another by a GaAs barrier layer. 11 figs.

  8. Photodetector with absorbing region having resonant periodic absorption between reflectors

    DOEpatents

    Bryan, Robert P.; Olbright, Gregory R.; Brennan, Thomas M.; Tsao, Jeffrey Y.

    1995-02-14

    A photodetector that is responsive to a wavelength or wavelengths of interest which have heretofore been unrealized. The photodetector includes a resonant cavity structure bounded by first and second reflectors, the resonant cavity structure being resonant at the wavelength or wavelengths of interest for containing a plurality of standing waves therein. The photodetector further includes a radiation absorbing region disposed within the resonant cavity structure, the radiation absorbing region including a plurality of radiation absorbing layers spaced apart from one another by a distance substantially equal to a distance between antinodes of adjacent ones of the standing waves. Each of radiation absorbing layers is spatially positioned at a location of one of the antinodes of one of the standing waves such that radiation absorption is enhanced. The radiation absorbing layers may be either bulk layers or quantum wells includes a plurality of layers, each of which is comprised of a strained layer of InGaAs. Individual ones of the InGaAs layers are spaced apart from one another by a GaAs barrier layer.

  9. From Anti-greenhouse Effect of Solar Absorbers to Cooling Effect of Greenhouse Gases: A 1-D Radiative Convective Model Study

    NASA Astrophysics Data System (ADS)

    Shia, R.

    2012-12-01

    The haze layer in Titan's upper atmosphere absorbs 90% of the solar radiation, but is inefficient for trapping infrared radiation generated by the surface. Its existence partially compensates for the greenhouse warming and keeps the surface approximately 9°C cooler than would otherwise be expected from the greenhouse effect alone. This is the so called anti-greenhouse effect (McKay et al., 1991). This effect can be used to alleviate the warming caused by the increasing level of greenhouse gases in the Earth's atmosphere. A one-dimensional radiative convective model (Kasting et al., 2009 and references listed there) is used to investigate the anti-greenhouse effect in the Earth atmosphere. Increasing of solar absorbers, e.g. aerosols and ozone, in the stratosphere reduces the surface solar flux and cool the surface. However, the absorption of the solar flux also increases the temperature in the upper atmosphere, while reduces the temperature at the surface. Thus, the temperature profile of the atmosphere changes and the regions with positive vertical temperature gradient are expanded. According to Shia (2010) the radiative forcing of greenhouse gases is directly related to the vertical temperature gradient. Under the new temperature profile increases of greenhouse gases should have less warming effect. When the solar absorbers keep increasing, eventually most of the atmosphere has positive temperature gradient and increasing greenhouse gases would cool the surface (Shia, 2011). The doubling CO2 scenario in the Earth atmosphere is simulated for different levels of solar absorbers using the 1-D RC model. The model results show that if the solar absorber increases to a certain level that less than 50% solar flux reaching the surface, doubling CO2 cools the surface by about 2 C. This means if the snowball Earth is generated by solar absorbers in the stratosphere, increasing greenhouse gases would make it freeze even more (Shia, 2011). References: Kasting, J. et al

  10. Biological damage of UV radiation in environments of F-type stars

    NASA Astrophysics Data System (ADS)

    Sato, Satoko

    I investigate the general astrobiological significance of F-type main-sequence stars with special consideration to stellar evolutionary aspects due to nuclear evolution. DNA is taken as a proxy for carbon-based macromolecules following the assumption that exobiology is most likely based on hydrocarbons. The DNA action spectrum is utilized to represent the relative damage of the stellar UV radiation. Planetary atmospheric attenuation is taken into account in the form of parameterized attenuation functions. My work is motivated by previous studies indicating that the UV environment of solar-like stars is one of the most critical elements in determining the habitability of exoplanets and exomoons. It contributes further to the exploration of the exobiological suitability of stars that are hotter and emit much higher photospheric UV fluxes than the Sun. I found that the damage inflicted on DNA for planets at Earth-equivalent positions is between 2.5 and 7.1 times higher than for solar-like stars, and there are intricate relations for the time-dependence of damage during stellar main-sequence evolution. If atmospheric attenuation is included, however, less damage is obtained in alignment to the attenuation parameters. Also, the outer part of late F-type stars have similar UV conditions to Earth. Therefore, F-type circumstellar environments should not be excluded from candidates for habitable places on the grounds of higher stellar UV emission than the Sun. Besides the extensive theoretical component of this study, emphasis is furthermore placed on applications to observed planetary systems including CoRoT-3, WASP-14, HD 197286, HD 179949, upsilon And, and HD 86264.

  11. HAC1 and HAF1 Histone Acetyltransferases Have Different Roles in UV-B Responses in Arabidopsis.

    PubMed

    Fina, Julieta P; Masotti, Fiorella; Rius, Sebastián P; Crevacuore, Franco; Casati, Paula

    2017-01-01

    Arabidopsis has 12 histone acetyltransferases grouped in four families: the GNAT/HAG, the MYST/HAM, the p300/CBP/HAC and the TAFII250/HAF families. We previously showed that ham1 and ham2 mutants accumulated higher damaged DNA after UV-B exposure than WT plants. In contrast, hag3 RNA interference transgenic plants showed less DNA damage and lower inhibition of plant growth by UV-B, and increased levels of UV-B-absorbing compounds. These results demonstrated that HAM1, HAM2, and HAG3 participate in UV-B-induced DNA damage repair and signaling. In this work, to further explore the role of histone acetylation in UV-B responses, a putative function of other acetyltransferases of the HAC and the HAF families was analyzed. Neither HAC nor HAF acetyltrasferases participate in DNA damage and repair after UV-B radiation in Arabidopsis. Despite this, haf1 mutants presented lower inhibition of leaf and root growth by UV-B, with altered expression of E2F transcription factors. On the other hand, hac1 plants showed a delay in flowering time after UV-B exposure and changes in FLC and SOC1 expression patterns. Our data indicate that HAC1 and HAF1 have crucial roles for in UV-B signaling, confirming that, directly or indirectly, both enzymes also have a role in UV-B responses.

  12. HAC1 and HAF1 Histone Acetyltransferases Have Different Roles in UV-B Responses in Arabidopsis

    PubMed Central

    Fina, Julieta P.; Masotti, Fiorella; Rius, Sebastián P.; Crevacuore, Franco; Casati, Paula

    2017-01-01

    Arabidopsis has 12 histone acetyltransferases grouped in four families: the GNAT/HAG, the MYST/HAM, the p300/CBP/HAC and the TAFII250/HAF families. We previously showed that ham1 and ham2 mutants accumulated higher damaged DNA after UV-B exposure than WT plants. In contrast, hag3 RNA interference transgenic plants showed less DNA damage and lower inhibition of plant growth by UV-B, and increased levels of UV-B-absorbing compounds. These results demonstrated that HAM1, HAM2, and HAG3 participate in UV-B-induced DNA damage repair and signaling. In this work, to further explore the role of histone acetylation in UV-B responses, a putative function of other acetyltransferases of the HAC and the HAF families was analyzed. Neither HAC nor HAF acetyltrasferases participate in DNA damage and repair after UV-B radiation in Arabidopsis. Despite this, haf1 mutants presented lower inhibition of leaf and root growth by UV-B, with altered expression of E2F transcription factors. On the other hand, hac1 plants showed a delay in flowering time after UV-B exposure and changes in FLC and SOC1 expression patterns. Our data indicate that HAC1 and HAF1 have crucial roles for in UV-B signaling, confirming that, directly or indirectly, both enzymes also have a role in UV-B responses. PMID:28740501

  13. Photoprotection, photosynthesis and growth of tropical tree seedlings under near-ambient and strongly reduced solar ultraviolet-B radiation.

    PubMed

    Krause, G Heinrich; Jahns, Peter; Virgo, Aurelio; García, Milton; Aranda, Jorge; Wellmann, Eckard; Winter, Klaus

    2007-10-01

    Seedlings of two late-successional tropical rainforest tree species, Tetragastris panamensis (Engler) O. Kuntze and Calophyllum longifolium (Willd.), were field grown for 3-4 months at an open site near Panama City (9 degrees N), Panama, under plastic films that either transmitted or excluded most solar UV-B radiation. Experiments were designed to test whether leaves developing under bright sunlight with strongly reduced UV-B are capable of acclimating to near-ambient UV-B conditions. Leaves of T. panamensis that developed under near-ambient UV-B contained higher amounts of UV-absorbing substances than leaves of seedlings grown under reduced UV-B. Photosynthetic pigment composition, content of alpha-tocopherol, CO(2) assimilation, potential photosystem II (PSII) efficiency (evaluated by F(v)/F(m) ratios) and growth of T. panamensis and C. longifolium did not differ between seedlings developed under near-ambient and reduced solar UV-B. When seedlings were transferred from the reduced UV-B treatment to the near-ambient UV-B treatment, a pronounced inhibition of photosynthetic capacity was observed initially in both species. UV-B-mediated inhibition of photosynthetic capacity nearly fully recovered within 1 week of the transfer in C. longifolium, whereas in T. panamensis an about 35% reduced capacity of CO(2) uptake was maintained. A marked increase in UV-absorbing substances was observed in foliage of transferred T. panamensis seedlings. Both species exhibited enhanced mid-day photoinhibition of PSII immediately after being transferred from the reduced UV-B to the near-ambient UV-B treatment. This effect was fully reversible within 1d in T. panamensis and within a few days in C. longifolium. The data show that leaves of these tropical tree seedlings, when developing in full-spectrum sunlight, are effectively protected against high solar UV-B radiation. In contrast, leaves developing under conditions of low UV-B lacked sufficient UV protection. They experienced a

  14. Implications of mycosporine-like amino acid and antioxidant defenses in UV-B radiation tolerance for the algae species Ptercladiella capillacea and Gelidium amansii.

    PubMed

    Lee, Tse-Min; Shiu, Chia-Tai

    2009-02-01

    Ultraviolet-B (UV-B) radiation (0.5, 1.0, 1.5, and 3.0Wm(-2)) induced higher H(2)O(2) production and lipid peroxidation in alga Gelidium amansii inhabiting in lower subtidal regions than upper subtidal alga Ptercladiella capillacea. Compared to G. amansii, mycosporine-like amino acid (MAA) concentration in P. capillacea was higher and can be increased by 0.5-1.0Wm(-2) UV-B, while carotenoid concentration was lower but also increased by 1.5-3.0Wm(-2) UV-B. UV-B increased ascorbate concentration, but to a higher degree in P. capillacea. UV-B decreased glutathione concentration, but to a higher degree in G. amansii. UV-B increased ascorbate peroxidase (APX) and glutathione reductase (GR) activities in P.capillacea but decreased them in G. amansii. UV-B increased superoxide dismutase and catalase activities, but to a higher degree in G. amansii. So, G. amansii suffered greater oxidative stress from UV-B radiation. P. capillacea can effectively reduce UV-B sensitivity by increasing sunscreen ability and antioxidant defense capacity.

  15. On the definition of absorbed dose

    NASA Astrophysics Data System (ADS)

    Grusell, Erik

    2015-02-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before.

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

    PubMed

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

    2017-11-01

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

  17. UV Tanning Equipment | Radiation Protection | US EPA

    EPA Pesticide Factsheets

    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.

  18. Radiative transfer and radiative driving of outflows in active galactic nuclei and starbursts

    NASA Astrophysics Data System (ADS)

    Novak, G. S.; Ostriker, J. P.; Ciotti, L.

    2012-12-01

    To facilitate the study of black hole fuelling, star formation and feedback in galaxies, we outline a method for treating the radial forces on interstellar gas due to absorption of photons by dust grains. The method gives the correct behaviour in all of the relevant limits [dominated by the central point source; dominated by the distributed isotropic source; optically thin; optically thick to ultraviolet (UV)/optical; optically thick to infrared (IR)] and reasonably interpolates between the limits when necessary. The method is explicitly energy conserving so that UV/optical photons that are absorbed are not lost, but are rather redistributed to the IR where they may scatter out of the galaxy. We implement the radiative transfer algorithm in a two-dimensional hydrodynamical code designed to study feedback processes in the context of early-type galaxies. We find that the dynamics and final state of simulations are measurably but only moderately affected by radiative forces on dust, even when assumptions about the dust-to-gas ratio are varied from zero to a value appropriate for the Milky Way. In simulations with high gas densities designed to mimic ultraluminous IR galaxies with a star formation rate of several hundred solar masses per year, dust makes a more substantial contribution to the dynamics and outcome of the simulation. We find that, despite the large opacity of dust to UV radiation, the momentum input to the flow from radiation very rarely exceeds L/c due to two factors: the low opacity of dust to the re-radiated IR and the tendency for dust to be destroyed by sputtering in hot gas environments. We also develop a simplification of our radiative transfer algorithm that respects the essential physics but is much easier to implement and requires a fraction of the computational cost.

  19. Topically Applied Carvedilol Attenuates Solar Ultraviolet Radiation Induced Skin Carcinogenesis.

    PubMed

    Huang, Kevin M; Liang, Sherry; Yeung, Steven; Oiyemhonlan, Etuajie; Cleveland, Kristan H; Parsa, Cyrus; Orlando, Robert; Meyskens, Frank L; Andresen, Bradley T; Huang, Ying

    2017-10-01

    In previous studies, the β-blocker carvedilol inhibited EGF-induced epidermal cell transformation and chemical carcinogen-induced mouse skin hyperplasia. As exposure to ultraviolet (UV) radiation leads to skin cancer, the present study examined whether carvedilol can prevent UV-induced carcinogenesis. Carvedilol absorbs UV like a sunscreen; thus, to separate pharmacological from sunscreen effects, 4-hydroxycarbazole (4-OHC), which absorbs UV to the same degree as carvedilol, served as control. JB6 P + cells, an established epidermal model for studying tumor promotion, were used for evaluating the effect of carvedilol on UV-induced neoplastic transformation. Both carvedilol and 4-OHC (1 μmol/L) blocked transformation induced by chronic UV (15 mJ/cm 2 ) exposure for 8 weeks. However, EGF-mediated transformation was inhibited by only carvedilol but not by 4-OHC. Carvedilol (1 and 5 μmol/L), but not 4-OHC, attenuated UV-induced AP-1 and NF-κB luciferase reporter activity, suggesting a potential anti-inflammatory activity. In a single-dose UV (200 mJ/cm 2 )-induced skin inflammation mouse model, carvedilol (10 μmol/L), applied topically after UV exposure, reduced skin hyperplasia and the levels of cyclobutane pyrimidine dimers, IL1β, IL6, and COX-2 in skin. In SKH-1 mice exposed to gradually increasing levels of UV (50-150 mJ/cm 2 ) three times a week for 25 weeks, topical administration of carvedilol (10 μmol/L) after UV exposure increased tumor latency compared with control (week 18 vs. 15), decreased incidence and multiplicity of squamous cell carcinomas, while 4-OHC had no effect. These data suggest that carvedilol has a novel chemopreventive activity and topical carvedilol following UV exposure may be repurposed for preventing skin inflammation and cancer. Cancer Prev Res; 10(10); 598-606. ©2017 AACR . ©2017 American Association for Cancer Research.

  20. Preillumination of lettuce seedlings with red light enhances the resistance of photosynthetic apparatus to UV-A.

    PubMed

    Kreslavski, Vladimir D; Lyubimov, Valery Yu; Shirshikova, Galina N; Shmarev, Alexander N; Kosobryukhov, Anatoly A; Schmitt, Franz-Josef; Friedrich, Thomas; Allakhverdiev, Suleyman I

    2013-05-05

    Seedlings of 10-day-old lettuce (Lactuca sativa L., cultivar Berlin) were preilluminated by low intensity red light (λmax=660 nm, 10 min, 5 μmol quanta m(-2) s(-1)) and far-red light (λmax=730 nm, 10 min, 5 μmol quanta m(-2) s(-1)) to study the effect of pre-treatment on photosynthesis, photochemical activity of photosystem II (PSII), the contents of photosynthetic and UV-A-absorbing pigments (UAPs) and H2O2, as well as total and ascorbate peroxidase activities in cotyledonary leaves of seedlings exposed to UV-A. UV radiation reduced the photosynthetic rate (Pn), the activity of PSII, and the contents of Chl a and b, carotenoids and UAPs in the leaves, but increased the content of H2O2 and the total peroxidase activity. Preillumination with red light removed these effects of UV. In turn, the illumination with red light, then far-red light removed the effect of the red light. Illumination with red light alone increased the content of UAPs, as well as peroxidase activity. It is suggested that higher resistance of the lettuce photosynthetic apparatus to UV-A radiation is associated with involvement of the active form of phytochrome B, thereby increasing peroxidase activities as well as UAPs and saving preservation of photosynthetic pigment contents due to pre-illumination with red light. Copyright © 2013 Elsevier B.V. All rights reserved.