Enzymological mechanism for the regulation of lanthanum chloride on flavonoid synthesis of soybean seedlings under enhanced ultraviolet-B radiation.

PubMed

Fan, Caixia; Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2014-01-01

In order to probe into the enzymological mechanism for the regulation of lanthanum chloride (LaCl3) on flavonoid synthesis in plants under enhanced ultraviolet-B (UV-B) radiation, the effects of LaCl₃ (20 and 60 mg l(-1)) on the content of flavonoids as well as the activities of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate : coenzyme A ligase (4CL), and chalcone synthase (CHS) in soybean seedlings under enhanced UV-B radiation (2.6 and 6.2 kJ m(-2) day(-1)) were investigated. Enhanced UV-B radiation (2.6 and 6.2 kJ m(-2) day(-1)) caused the increase in the content of flavonoids as well as the activities of PAL, C4H, 4CL, and CHS in soybean seedlings. The treatment of 20 mg l(-1) LaCl₃ also efficiently increased these indices, which promoted the flavonoid synthesis and provided protective effects for resisting enhanced UV-B radiation. On the contrary, the treatment of 60 mg l(-1) LaCl₃ decreased the content of flavonoids as well as the activities of C4H, 4CL, and CHS in soybean seedlings except increasing the activity of PAL, which were not beneficial to the flavonoid synthesis and provided negative effects for resisting enhanced UV-B radiation. In conclusion, enhanced UV-B radiation caused the increase in the flavonoid synthesis by promoting the activities of PAL, C4H, 4CL, and CHS in soybean seedlings. The treatment of LaCl₃ could change flavonoid synthesis in soybean seedlings under enhanced UV-B radiation by regulating the activities of PAL, C4H, 4CL, and CHS, which is an enzymological mechanism for the regulation of LaCl₃ on flavonoid synthesis in plants under enhanced UV-B radiation.

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.

Hypersensitivity of skin fibroblasts from basal cell nevus syndrome patients to killing by ultraviolet B but not by ultraviolet C radiation

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

Applegate, L.A.; Goldberg, L.H.; Ley, R.D.

Basal cell nevus syndrome (BCNS) is an autosomal dominant genetic disorder in which the afflicted individuals are extremely susceptible to sunlight-induced skin cancers, particularly basal cell carcinomas. However, the cellular and molecular basis for BCNS is unknown. To ascertain whether there is any relationship between genetic predisposition to skin cancer and increased sensitivity of somatic cells from BCNS patients to killing by UV radiation, we exposed skin fibroblasts established from unexposed skin biopsies of several BCNS and age- and sex-matched normal individuals to either UV-B (280-320 nm) or UV-C (254 nm) radiation and determined their survival. The results indicated thatmore » skin fibroblasts from BCNS patients were hypersensitive to killing by UV-B but not UV-C radiation as compared to skin fibroblasts from normal individuals. DNA repair studies indicated that the increased sensitivity of BCNS skin fibroblasts to killing by UV-B radiation was not due to a defect in the excision repair of pyrimidine dimers. These results indicate that there is an association between hypersensitivity of somatic cells to killing by UV-B radiation and the genetic predisposition to skin cancer in BCNS patients. In addition, these results suggest that DNA lesions (and repair processes) other than the pyrimidine dimer are also involved in the pathogenesis of sunlight-induced skin cancers in BCNS patients. More important, the UV-B sensitivity assay described here may be used as a diagnostic tool to identify presymptomatic individuals with BCNS.« less

Inactivation of Staphylococcus saprophyticus in chicken meat and exudate using high pressure processing, gamma radiation, and ultraviolet light

USDA-ARS?s Scientific Manuscript database

Stapylococcus saprophyticus is a common contaminant in foods and causes urinary tract infections in humans. Three nonthermal food safety intervention technologies used to improve the safety foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). A...

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

Efficacy of ultraviolet radiation as an alternative technology to inactivate microorganisms in grape juices and wines.

PubMed

Fredericks, Ilse N; du Toit, Maret; Krügel, Maricel

2011-05-01

Since sulphur dioxide (SO(2)) is associated with health risks, the wine industry endeavours to reduce SO(2) levels in wines with new innovative techniques. The aim of this study was, therefore, to investigate the efficacy of ultraviolet radiation (UV)-C (254 nm) as an alternative technology to inactivate microorganisms in grape juices and wines. A pilot-scale UV-C technology (SurePure, South Africa) consisting of an UV-C germicidal lamp (100 W output; 30 W UV-C output) was used to apply UV-C dosages ranging from 0 to 3672 J l(-1), at a constant flow rate of 4000 l h(-1) (Re > 7500). Yeasts, lactic and acetic acid bacteria were singly and co-inoculated into 20 l batches of Chenin blanc juice, Shiraz juice, Chardonnay wine and Pinotage wine, respectively. A dosage of 3672 J l(-1), resulted in an average log(10) microbial reduction of 4.97 and 4.89 in Chardonnay and Pinotage, respectively. In Chenin blanc and Shiraz juice, an average log(10) reduction of 4.48 and 4.25 was obtained, respectively. UV-C efficacy may be influenced by liquid properties such as colour and turbidity. These results had clearly indicated significant (p < 0.05) germicidal effect against wine-specific microorganisms; hence, UV-C radiation may stabilize grape juice and wine microbiologically in conjunction with reduced SO(2) levels. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effects of ultraviolet-B radiation on fungal disease development in Cucumis sativus

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

Orth, A.B.; Teramura, A.H.; Sisler, H.D.

1990-09-01

Stratospheric ozone depletion due to increased atmospheric pollutants has received considerable attention because of the potential increase in ultraviolet-B (UV-B, 280-320 nm) radiation that will reach the earth's surface. Three cucumber (Cucumis sativus L.) cultivars were exposed to a daily dose of 11.6 kJ m{sup {minus}2} biologically effective ultraviolet-B (UV-B{sub BE}) radiation in an unshaded greenhouse before and/or after injection by Colletotrichum lagenarium (Pass.) Ell. and Halst. or Cladosporium cucumerinum Ell. and Arth. and analyzed for disease development. Two of these cultivars, Poinsette and Calypso Hybrid, were disease resistant, while the third cultivar, Straight-8, was disease susceptible. Preinfectional treatment ofmore » 1 to 7 days with UV-B{sub BE} in Straight-8 led to greater severity of both diseases. Postinfectional UV treatment did not lead to increased disease severity caused by C. lagenarium, while preinfectional UV treatment in both Straight-8 and Poinsette substantially increased disease severity. Although resistant cultivars Poinsette and Calypso Hybrid showed increased anthracnose disease severity when exposed to UV-B, this effect was apparent only on the cotyledons. Both higher spore concentration and exposure to UV-B radiation resulted in greater disease severity. Of the cucumber cultivars tested for UV-B sensitivity, growth in Poinsette was most sensitive and Calypso Hybrid was least sensitive. These preliminary results indicate that the effects of UV-B radiation on disease development in cucumber vary depending on cultivar, timing and duration of UV-B exposure, inoculation level, and plant age.« less

Studies on the resistance/reactivation of Giardia muris cysts and Cryptosporidium parvum oocysts exposed to medium-pressure ultraviolet radiation.

PubMed

Belosevic, M; Craik, S A; Stafford, J L; Neumann, N F; Kruithof, J; Smith, D W

2001-10-16

The ex vivo and in vivo reactivation of Giardia muris cysts and Cryptosporidium parvum oocysts after exposure to different doses of ultraviolet (UV) radiation was determined using animal infectivity. The infectivity of UV-treated parasites stored for 1-4 days (G. muris) or 1-17 days (C. parvum) at room temperature in the dark was similar to that of organisms administered immediately after UV treatment, indicating that the parasites did not reactivate ex vivo. In contrast, we observed in vivo reactivation of G. muris in three of seven independent animal infectivity experiments, when parasites were treated with relatively low doses of medium-pressure UV (<25 mJ/cm(2)). Our observations indicate that G. muris cysts and C. parvum oocysts exposed to medium-pressure UV doses of 60 mJ/cm(2) or higher did not exhibit resistance to and/or reactivation following treatment. This suggests that when appropriate doses of UV are used, significant and permanent inactivation of these parasites may be achieved.

Methods for assessing the impacts of ultraviolet-B radiation on aquatic invertebrates

USGS Publications Warehouse

Hurtubise, R.D.; Little, Edward E.; Havel, J.E.; Little, Edward E.; Greenberg, Bruce M.; Delonay, Aaron J.

1998-01-01

A standard methodology for assessing the impacts of simulated solar ultraviolet-B radiation (UV-B) on aquatic invertebrates was established. A solar simulator was used to expose a variety of aquatic invertebrates to different levels of UV-B. The simulator was calibrated as close as possible to match local ambient solar radiation measured in and out of water with a scanning spectroradiometer. A series of repeated exposures were conducted to determine the effects of UV-B on two species of Ceriodaphnia. Survivorship of C. reticulata declined with increasing UV-B with 100% mortality occurring after four daily 5 hr exposures to a UV-B irradiance that was 14% of ambient sunlight (40.8/μW/cm2) and 70% mortality for C. dubia after seven days of an exposure to 5% of ambient (14.5μW/cm2). Significant reductions in fertility (#young/adult) was observed in both low and high light adapted individuals with low light individuals appearing to be more sensitive. This methodology allowed us to make comparisons to natural conditions in aquatic habitats and to make risk assessments for individual species.

Reactor for simulation and acceleration of solar ultraviolet damage

NASA Technical Reports Server (NTRS)

Laue, E.; Gupta, A.

1979-01-01

An environmental test chamber providing acceleration of UV radiation and precise temperature control (+ or -)1 C was designed, constructed and tested. This chamber allows acceleration of solar ultraviolet up to 30 suns while maintaining temperature of the absorbing surface at 30 C - 60 C. This test chamber utilizes a filtered medium pressure mercury arc as the source of radiation, and a combination of selenium radiometer and silicon radiometer to monitor solar ultraviolet (295-340 nm) and total radiant power output, respectively. Details of design and construction and operational procedures are presented along with typical test data.

Ultraviolet light assisted extraction of flavonoids and allantoin from aqueous and alcoholic extracts of Symphytum officinale

PubMed Central

Al-Nimer, Marwan S. M.; Wahbee, Zainab

2017-01-01

Aim: Symphytum officinale (comfrey) is a medicinal plant commonly used in decoction and to treat ailments. It protects the skin against ultraviolet (UV)-irradiation. UV irradiation may induce variable effects on the constituents of herbal extracts and thereby may limit or improve the advantages of using these extracts as medicinal supplements. This study aimed to assess the effect of UV radiations including UV-A, UV-B, and UV-C on the constituents of S. officinale aqueous and alcoholic extracts. Materials and Methods: Comfrey extracts (1% w/v) were prepared using distilled water, ethanol, and methanol. They were exposed to wavelengths of UV-A, UV-B, and UV-C for 10 min. The principal peak on the UV-spectroscopy scanning, the flavonoids, reducing power, and the allantoin levels were determined before and after irradiation. Results: UV irradiation reduces the magnitude of the principle peak at 355 nm wavelength of the aqueous infusion and methanol extracts. It improves the levels of flavonoids and reducing power of the aqueous extracts and increases the levels of allanotoin in aqueous and methanol extracts. Conclusions: UV-radiation enhances the yields of active ingredient of comfrey extracted with methanol, whereas improves the flavonoids, reducing power, and allantoin levels of comfrey extracted by the aqueous infusion method. UV-radiation reduces the levels of flavonoids, reducing power and allantoin when the comfrey extracted by alcohols. PMID:28894626

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.

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

NASA Technical Reports Server (NTRS)

Robberecht, R.; Caldwell, M. M.

1981-01-01

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

The effects of ultraviolet-B radiation on freshwater invertebrates: Experiments with a solar simulator

USGS Publications Warehouse

Hurtubise, R.D.; Havel, J.E.; Little, E.E.

1998-01-01

There is concern that decreases in stratospheric ozone will lead to hazardous levels of ultraviolet-B (UV-B) radiation at the Earth's surface. In clear water, UV-B may penetrate to significant depths. The purpose of the current study was to compare the sensitivity of freshwater invertebrates to UV-B. We used a solar simulator, calibrated to match local ambient solar radiation, to expose five species of freshwater invertebrates to enhanced levels of UV-B radiation. UV-B measurements in a eutrophic pond revealed that 10% of the irradiance penetrated to 30-cm depth and 1% to 57-cm depth. The irradiance at the upper 5-20 cm was comparable to levels used in the simulator. Median lethal dose (LD50) values were determined for the cladocerans Ceriodaphnia reticulata, Scapholeberis kingii (two induced color morphs), and Daphnia magna; the ostracod Cyprinotus incongruens; and the amphipod Hyalella azteca. Among the species, 96-h LD50 estimates were quite variable, ranging from 4.2 to 84.0 ??W cm-2. These estimates indicated S. kingii to be highly sensitive and H. azteca, C. reticulata, and D. magna to be moderately sensitive, whereas the ostracod C. incongruens was very tolerant to UV-B radiation. Overall, this study suggests that, in shallow ponds without physical refuges, UV-B radiation would have the strongest effects upon cladocerans and amphipods occurring in the water column, whereas ostracods would be better protected.

Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight

DTIC Science & Technology

2012-07-01

organisms deposited on surfaces, suspended in water , and contaminating food, all of which have been discussed elsewhere (Block, 2001). In contrast, the... water . Therefore, the primary means for organism inactivation in aerosols is ultraviolet (UV) radiation. Radiation from the sunlight is used as a...cortex is essential for reduction of the water content in the spore core and formation of a dormant spore. The cortex is degraded in spore

Ultraviolet-C efficacy against a norovirus surrogate and hepatitis A virus on a stainless steel surface.

PubMed

Park, Shin Young; Kim, An-Na; Lee, Ki-Hoon; Ha, Sang-Do

2015-10-15

In this study, the effects of 10-300 mWs/cm(2) of ultraviolet radiation (UV-C) at 260 nm were investigated for the inactivation of two foodborne viruses: murine norovirus-1 (MNV-1; a human norovirus [NoV] surrogate) and hepatitis A virus (HAV). We used an experimentally contaminated stainless steel surface, a common food-contact surface, to examine the effects of low doses of UV-C radiation on MNV-1 and HAV titers. The modified Gompertz equation was used to generate non-linear survival curves and calculate dR-values as the UV-C dose of 90% reduction for MNV-1 (R(2)=0.95, RMSE=0.038) and HAV (R(2)=0.97, RMSE=0.016). Total MNV-1 and HAV titers significantly decreased (p<0.05) with higher doses of UV-C. MNV-1 and HAV were reduced to 0.0-4.4 and 0.0-2.6 log10PFU/ml, respectively, on the stainless steel surfaces by low-dose UV-C treatment. The dR-value, 33.3 mWs/cm(2) for MNV-1 was significantly (p<0.05) lower than 55.4 mWs/cm(2) of HAV. Therefore, the present study shows that HAV is more resistant to UV-C radiation than MNV-1. These data suggest that low doses of UV-C light on food contact surfaces could be effective to inactivate human NoV and HAV in restaurant, institutional, and industrial kitchens and facilities. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluating optical hazards from plasma arc cutting.

PubMed

Glassford, Eric; Burr, Gregory

2018-01-01

The Health Hazard Evaluation Program of the National Institute for Occupational Safety and Health evaluated a steel building materials manufacturer. The employer requested the evaluation because of concerns about optical radiation hazards from a plasma arc cutting system and the need to clarify eye protection requirements for plasma operators, other employees, and visitors. The strength of the ultraviolet radiation, visible radiation (light), and infrared radiation generated by the plasma arc cutter was measured at various distances from the source and at different operating amperages. Investigators also observed employees performing the plasma arc cutting. Optical radiation above safe levels for the unprotected eyes in the ultraviolet-C, ultraviolet-B, and visible light ranges were found during plasma arc cutting. In contrast, infrared and ultraviolet-A radiation levels during plasma arc cutting were similar to background levels. The highest non-ionizing radiation exposures occurred when no welding curtains were used. A plasma arc welding curtain in place did not eliminate optical radiation hazards to the plasma arc operator or to nearby employees. In most instances, the measured intensities for visible light, UV-C, and UV-B resulted in welding shade lens numbers that were lower than those stipulated in the OSHA Filter Lenses for Protection Against Radiant Energy table in 29 CFR 1910.133(a)(5). [1] Investigators recommended using a welding curtain that enclosed the plasma arc, posting optical radiation warning signs in the plasma arc cutter area, installing audible or visual warning cues when the plasma arc cutter was operating, and using welding shades that covered the plasma arc cutter operator's face to protect skin from ultraviolet radiation hazards.

Spectral transmission of the pig lens: effect of ultraviolet A+B radiation.

PubMed

Artigas, C; Navea, A; López-Murcia, M-M; Felipe, A; Desco, C; Artigas, J-M

2014-12-01

To determine the spectral transmission curve of the crystalline lens of the pig. To analyse how this curve changes when the crystalline lens is irradiated with ultraviolet A+B radiation similar to that of the sun. To compare these results with literature data from the human crystalline lens. We used crystalline lenses of the common pig from a slaughterhouse, i.e. genetically similar pigs, fed with the same diet, and slaughtered at six months old. Spectral transmission was measured with a Perkin-Elmer Lambda 35 UV/VIS spectrometer. The lenses were irradiated using an Asahi Spectra Lax-C100 ultraviolet source, which made it possible to select the spectral emission band as well as the intensity and exposure time. The pig lens transmits all the visible spectrum (95%) and lets part of the ultraviolet A through (15%). Exposure to acute UV (A+B) irradiation causes a decrease in its transmission as the intensity or exposure time increases: this decrease is considerable in the UV region. We were able to determine the mean spectral transmission curve of the pig lens. It appears to be similar to that of the human lens in the visible spectrum, but different in the ultraviolet. Pig lens transmission is reduced by UV (A+B) irradiation and its transmission in the UV region can even disappear as the intensity or exposure time increases. An adequate exposure intensity and time of UV (A+B) radiation always causes an anterior subcapsular cataract (ASC). Copyright © 2014. Published by Elsevier Masson SAS.

Ultraviolet radiation, human health, and the urban forest

Treesearch

Gordon M. Heisler; Richard H. Grant

2000-01-01

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

Two ultraviolet radiation datasets that cover China

NASA Astrophysics Data System (ADS)

Liu, Hui; Hu, Bo; Wang, Yuesi; Liu, Guangren; Tang, Liqin; Ji, Dongsheng; Bai, Yongfei; Bao, Weikai; Chen, Xin; Chen, Yunming; Ding, Weixin; Han, Xiaozeng; He, Fei; Huang, Hui; Huang, Zhenying; Li, Xinrong; Li, Yan; Liu, Wenzhao; Lin, Luxiang; Ouyang, Zhu; Qin, Boqiang; Shen, Weijun; Shen, Yanjun; Su, Hongxin; Song, Changchun; Sun, Bo; Sun, Song; Wang, Anzhi; Wang, Genxu; Wang, Huimin; Wang, Silong; Wang, Youshao; Wei, Wenxue; Xie, Ping; Xie, Zongqiang; Yan, Xiaoyuan; Zeng, Fanjiang; Zhang, Fawei; Zhang, Yangjian; Zhang, Yiping; Zhao, Chengyi; Zhao, Wenzhi; Zhao, Xueyong; Zhou, Guoyi; Zhu, Bo

2017-07-01

Ultraviolet (UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.

Growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus upon ultraviolet radiation.

PubMed

Yeo, Siok-Koon; Liong, Min-Tze

2012-11-01

The objective of this study was to evaluate the effects of ultraviolet (UV) radiation (UVB; 90 J/m²) on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of L. casei FTDC 2113. UV radiation significantly enhanced (P < 0.05) the growth of parent cells in mannitol-soymilk fermented at 37°C for 24 h. This had led to an enhanced intracellular and extracellular β-glucosidase activity with a subsequent increase in bioconversion of isoflavones in mannitol-soymilk (P < 0.05). UV radiation also promoted (P < 0.05) the tolerance of parent cells towards acidic condition (pH 2 and 3) and intestinal bile salts (oxgall, taurocholic and cholic acid). In addition, parent treated cells also exhibited better (P < 0.05) adhesion ability to mucin and antimicrobial activity compared to that of the control. All these positive effects of UV radiation were only prevalent in the parent cells without inheritance by first, second and third passage of cells. Although temporary, our results suggested that UV radiation could enhance the bioactive and probiotic potentials of L. casei FTDC 2113, and thus could be applied for the production of probiotic products with enhanced bioactivity.

Ultraviolet radiation changes

NASA Technical Reports Server (NTRS)

Mckenzie, Richard L.; Frederick, John E.; Ilyas, Mohammad; Filyushkin, V.; Wahner, Andreas; Stamnes, K.; Muthusubramanian, P.; Blumthaler, M.; Roy, Colin E.; Madronich, Sasha

1991-01-01

A major consequence of ozone depletion is an increase in solar ultraviolet (UV) radiation received at the Earth's surface. This chapter discusses advances that were made since the previous assessment (World Meteorological Organization (WMO)) to our understanding of UV radiation. The impacts of these changes in UV on the biosphere are not included, because they are discussed in the effects assessment.

Ultraviolet radiation-blocking characteristics of contact lenses: relevance to eye protection for psoralen-sensitised patients.

PubMed

Anstey, A; Taylor, D; Chalmers, I; Ansari, E

1999-10-01

Nine brands of contact lens marketed as "UV protective" were tested for ultraviolet (UV) transmission in order to assess potential suitability for psoralen-sensitised patients. UV-transmission characteristics of hydrated lenses was tested with a Bentham monochromator spectro-radiometer system. All lenses showed minimal transmission loss in the visible band. The performance of the nine lenses was uniform for ultraviolet B radiation with negligible transmission, but showed variation in transmission for ultraviolet A radiation. None of the lenses complied with UV-transmission criteria used previously to assess UV-blocking spectacles. Only two lenses had UV-blocking characteristics which came close to the arbitrary criteria used. The performance of ordinary soft and hard lenses was very similar, with negligible blocking of UV radiation. None of the nine contact lenses marketed as "UV protective" excluded sufficient UVA to comply with criteria in current use to assess UV protection in spectacles for psoralen-sensitised patients. However, the improved UV-blocking characteristics of contact lenses identified in this paper compared to previous studies suggests that such a contact lens will soon become available. Meanwhile, contact lens-wearing systemically sensitised PUVA patients should continue to wear approved spectacles for eye protection whilst photosensitised with psoralen.

DEMONSTRATION BULLETIN - ULTROX INTERNATIONAL, INC. ULTRAVIOLET RADIATION AND OXIDATION

EPA Science Inventory

The ultraviolet (UV) radiation/oxidation treatment technology developed by Ultrox International uses a combination of UV radiation, ozone, and hydrogen peroxide to oxidize organic compounds in water. Various operating parameters can be adjusted in the Ultrox® system to enhan...

Visible-blind ultraviolet photodetectors on porous silicon carbide substrates

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

Naderi, N.; Hashim, M.R., E-mail: roslan@usm.my

2013-06-01

Highlights: • Highly reliable UV detectors are fabricated on porous silicon carbide substrates. • The optical properties of samples are enhanced by increasing the current density. • The optimized sample exhibits enhanced sensitivity to the incident UV radiation. - Abstract: Highly reliable visible-blind ultraviolet (UV) photodetectors were successfully fabricated on porous silicon carbide (PSC) substrates. High responsivity and high photoconductive gain were observed in a metal–semiconductor–metal ultraviolet photodetector that was fabricated on an optimized PSC substrate. The PSC samples were prepared via the UV-assisted photo-electrochemical etching of an n-type hexagonal silicon carbide (6H-SiC) substrate using different etching current densities. Themore » optical results showed that the current density is an outstanding etching parameter that controls the porosity and uniformity of PSC substrates. A highly porous substrate was synthesized using a suitable etching current density to enhance its light absorption, thereby improving the sensitivity of UV detector with this substrate. The electrical characteristics of fabricated devices on optimized PSC substrates exhibited enhanced sensitivity and responsivity to the incident radiation.« less

Tolerance to Ultraviolet Radiation of Psychrotolerant Yeasts and Analysis of Their Carotenoid, Mycosporine, and Ergosterol Content.

PubMed

Villarreal, Pablo; Carrasco, Mario; Barahona, Salvador; Alcaíno, Jennifer; Cifuentes, Víctor; Baeza, Marcelo

2016-01-01

Yeasts colonizing the Antarctic region are exposed to a high ultraviolet radiation evolving mechanisms to minimize the UV radiation damages, such as the production of UV-absorbing or antioxidant compounds like carotenoid pigments and mycosporines. Ergosterol has also been suggested to play a role in this response. These compounds are also economically attractive for several industries such as pharmaceutical and food, leading to a continuous search for biological sources of them. In this work, the UV-C radiation tolerance of yeast species isolated from the sub-Antarctic region and their production of carotenoids, mycosporines, and ergosterol were evaluated. Dioszegia sp., Leuconeurospora sp. (T27Cd2), Rhodotorula laryngis, Rhodotorula mucilaginosa, and Cryptococcus gastricus showed the highest UV-C radiation tolerance. The yeasts with the highest content of carotenoids were Dioszegia sp. (OHK torulene), Rh. laryngis (torulene and lycopene), Rh. mucilaginosa, (torulene, gamma carotene, and lycopene), and Cr. gastricus (2-gamma carotene). Probable mycosporine molecules and biosynthesis intermediates were found in Rh. laryngis, Dioszegia sp., Mrakia sp., Le. creatinivora, and Leuconeurospora sp. (T27Cd2). Ergosterol was the only sterol detected in all yeasts, and M. robertii and Le. creatinivora showed amounts higher than 4 mg g−1. Although there was not a well-defined relation between UV-C tolerance and the production of these three kinds of compounds, the majority of the yeasts with lower amounts of carotenoids showed lower UV-C tolerance. Dioszegia sp., M. robertii, and Le. creatinivora were the greatest producers of carotenoids, ergosterol, and mycosporines, respectively, representing good candidates for future studies intended to increase their production for large-scale applications.

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

Some Thoughts on Teaching about Ultraviolet Radiation

ERIC Educational Resources Information Center

Thumm, Walter

1975-01-01

Describes the major obstacles in the study of ultraviolet radiation (UV). Presents the beneficial aspects of UV such as vitamin O production, sterilization, clinical treatment of diseases and wounds, and the marking of patients for radiotherapy. Warns of the dangers of UV exposure such as skin cancer and early aging. (GS)

Influence of ultraviolet-C radiation on some growth parameters of mycorrhizal wheat plants.

PubMed

Rahmatzadeh, Samaneh; Khara, Jalil

2007-12-01

UV-C radiation (220-280 nm) is known to causing damage in some physiological growth parameters such as chlorophyll, carotenoid, protein and sugar contents. In this study, effect of some species of vesicular arbuscular mycorrhizal fungi on tolerance of UV-C radiation in wheat plants was studied. Wheat (Triticum aestivum L. cv. Azar2) plants colonized by three species of mycorrhizae namely Glomus etunicatum, Glomus intraradices and Glomus veruciforme were used in this study. They have been exposed to UV-C (254 nm) light for 7 h (28 days, 15 min each day). We measured total proteins, sugars, chlorophyll a and b and carotenoids. Our study showed that UV-C radiation decreases chlorophylls, carotenoids and sugars contents. But this effect on total proteins content has not been significant. However, mycorrhizal fungi could increase all of these factors in comparison to non-mycorrhizal samples. Therefore, these fungi species can increase above growth factors of wheat plants, apparently.

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...

Effect of various conditions on inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in fresh-cut lettuce using ultraviolet radiation.

PubMed

Kim, Yoon-Hee; Jeong, Seul-Gi; Back, Kyeong-Hwan; Park, Ki-Hwan; Chung, Myung-Sub; Kang, Dong-Hyun

2013-09-16

The effect of various conditions on inactivation of foodborne pathogens and quality of fresh-cut lettuce during ultraviolet (254 nm, UVC) radiation was investigated. Lettuce was inoculated with a cocktail of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and treated at different temperatures (4 and 25 °C), distances between sample and lamp (10 and 50 cm), type of exposure (illuminated from one or two sides), UV intensities (1.36 to 6.80 mW/cm²), and exposure times (0.5 to 10 min), sequentially. UV treatment at 25 °C for 1 min achieved 1.45-, 1.35-, and 2.12-log reductions in surface-inoculated E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, whereas the reduction of these pathogens at 4 °C was 0.31, 0.57, and 1.16 log, respectively. UV radiation was most effective when distance from UV lamp to the sample was minimal (10 cm) and radiation area was maximal (two-sided exposure). All UV intensities significantly (P<0.05) reduced the three pathogens after 10 min exposure, but the effect of treatment was correlated with UV intensity and exposure time. Color values and texture parameters of lettuce subjected to UV treatment under the optimum conditions (25 °C, 10 cm between sample and lamp, two-sided exposure, 6.80 mW/cm²) were not significantly (P>0.05) different from those of nontreated samples up to 5 min exposure. However, these qualities significantly (P<0.05) changed at prolonged treatment time. These results suggest that UV radiation under optimized conditions could reduce foodborne pathogens without adversely affecting color quality properties of fresh-cut lettuce. © 2013 Elsevier B.V. All rights reserved.

Control of browning of minimally processed mangoes subjected to ultraviolet radiation pulses.

PubMed

de Sousa, Aline Ellen Duarte; Fonseca, Kelem Silva; da Silva Gomes, Wilny Karen; Monteiro da Silva, Ana Priscila; de Oliveira Silva, Ebenézer; Puschmann, Rolf

2017-01-01

The pulsed ultraviolet radiation (UV P ) has been used as an alternative strategy for the control of microorganisms in food. However, its application causes the browning of minimally processed fruits and vegetables. In order to control the browning of the 'Tommy Atkins' minimally processed mango and treated with UV P (5.7 J cm -2 ) it was used 1-methylcyclopropene (1-MCP) (0.5 μL L -1 ), an ethylene action blocker in separate stages, comprising five treatments: control, UV P (U), 1-MCP + UV P (M + U), UV P  + 1-MCP (U + M) e 1-MCP + UV P  + 1-MCP (M + U + M). At the 1st, 7th and 14th days of storage at 12 °C, we evaluated the color (L* and b*), electrolyte leakage, polyphenol oxidase, total extractable polyphenols, vitamin C and total antioxidant activity. The 1-MCP, when applied before UV P , prevented the loss of vitamin C and when applied in a double dose, retained the yellow color (b*) of the cubes. However, the 1-MCP reduced lightness (L*) of independent mango cubes whatever applied before and/or after the UV P . Thus, the application of 1-MCP did not control, but intensified the browning of minimally processed mangoes irradiated with UV P .

Effect of Lot Variability on Ultraviolet Radiation Inactivation Kinetics of Cryptosporidium parvum Oocysts

EPA Science Inventory

Numerous studies have demonstrated the efficiency of ultraviolet (UV) radiation for the inactivation of oocysts of Cryptosporidium parvum. In these studies inactivation is measured as reduction in oocysts. A primary goal is to estimate the UV radiation required to achiev...

Low cost, patterning of human hNT brain cells on parylene-C with UV & IR laser machining.

PubMed

Raos, Brad J; Unsworth, C P; Costa, J L; Rohde, C A; Doyle, C S; Delivopoulos, E; Murray, A F; Dickinson, M E; Simpson, M C; Graham, E S; Bunting, A S

2013-01-01

This paper describes the use of 800nm femtosecond infrared (IR) and 248nm nanosecond ultraviolet (UV) laser radiation in performing ablative micromachining of parylene-C on SiO2 substrates for the patterning of human hNT astrocytes. Results are presented that support the validity of using IR laser ablative micromachining for patterning human hNT astrocytes cells while UV laser radiation produces photo-oxidation of the parylene-C and destroys cell patterning. The findings demonstrate how IR laser ablative micromachining of parylene-C on SiO2 substrates can offer a low cost, accessible alternative for rapid prototyping, high yield cell patterning.

Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair

PubMed Central

Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

2015-01-01

Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400–700 nm), PAR plus ultraviolet-A (320–400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280–320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain, suggesting negative effects of global climate change on microalgae inhabiting (circum-) polar regions. For temperate and tropical strains of Chlorella, damage from UVR was independent of temperature but the repair constant increased with increasing temperature, implying an improved ability of these strains to recover from UVR stress under global warming. PMID:26427046

Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair.

PubMed

Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

2015-01-01

Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400-700 nm), PAR plus ultraviolet-A (320-400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280-320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain, suggesting negative effects of global climate change on microalgae inhabiting (circum-) polar regions. For temperate and tropical strains of Chlorella, damage from UVR was independent of temperature but the repair constant increased with increasing temperature, implying an improved ability of these strains to recover from UVR stress under global warming.

QUALITY ASSURANCE AND SITE MANAGEMENT FOR PRIMENET AND URBAN ULTRAVIOLET RADIATION RESEARCH MONITORING PROGRAM.

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...

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.

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.

Effects of radiation and temperature on gallium nitride (GaN) metal-semiconductor-metal ultraviolet photodetectors

NASA Astrophysics Data System (ADS)

Chiamori, Heather C.; Angadi, Chetan; Suria, Ateeq; Shankar, Ashwin; Hou, Minmin; Bhattacharya, Sharmila; Senesky, Debbie G.

2014-06-01

The development of radiation-hardened, temperature-tolerant materials, sensors and electronics will enable lightweight space sub-systems (reduced packaging requirements) with increased operation lifetimes in extreme harsh environments such as those encountered during space exploration. Gallium nitride (GaN) is a ceramic, semiconductor material stable within high-radiation, high-temperature and chemically corrosive environments due to its wide bandgap (3.4 eV). These material properties can be leveraged for ultraviolet (UV) wavelength photodetection. In this paper, current results of GaN metal-semiconductor-metal (MSM) UV photodetectors behavior after irradiation up to 50 krad and temperatures of 15°C to 150°C is presented. These initial results indicate that GaN-based sensors can provide robust operation within extreme harsh environments. Future directions for GaN-based photodetector technology for down-hole, automotive and space exploration applications are also discussed.

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

NASA Astrophysics Data System (ADS)

Bai, Jianhui; Wang, Gengchen

2003-09-01

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

Ultraviolet Radiation-Elicited Enhancement of Isoflavonoid Accumulation, Biosynthetic Gene Expression, and Antioxidant Activity in Astragalus membranaceus Hairy Root Cultures.

PubMed

Jiao, Jiao; Gai, Qing-Yan; Wang, Wei; Luo, Meng; Gu, Cheng-Bo; Fu, Yu-Jie; Ma, Wei

2015-09-23

In this work, Astragalus membranaceus hairy root cultures (AMHRCs) were exposed to ultraviolet radiation (UV-A, UV-B, and UV-C) for promoting isoflavonoid accumulation. The optimum enhancement for isoflavonoid production was achieved in 34-day-old AMHRCs elicited by 86.4 kJ/m(2) of UV-B. The resulting isoflavonoid yield was 533.54 ± 13.61 μg/g dry weight (DW), which was 2.29-fold higher relative to control (232.93 ± 3.08 μg/g DW). UV-B up-regulated the transcriptional expressions of all investigated genes involved in isoflavonoid biosynthetic pathway. PAL and C4H were found to be two potential key genes that controlled isoflavonoid biosynthesis. Moreover, a significant increase was noted in antioxidant activity of extracts from UV-B-elicited AMHRCs (IC50 values = 0.85 and 1.08 mg/mL) in comparison with control (1.38 and 1.71 mg/mL). Overall, this study offered a feasible elicitation strategy to enhance isoflavonoid accumulation in AMHRCs and also provided a basis for metabolic engineering of isoflavonoid biosynthesis in the future.

Visible light neutralizes the effect produced by ultraviolet radiation in proteins.

PubMed

Espinoza, J Horacio; Mercado-Uribe, Hilda

2017-02-01

The damage produced by UV-C radiation (100-280nm) in organisms and cells is a well known fact. The main reactions of proteins to UV-C radiation consist in the alteration of their secondary structures, exposure of hydrophobic residues, unfolding and aggregation. Furthermore, it has been found that electromagnetic radiation of lower energy (visible light, where wavelengths are between 400 and 750nm) also induces different disturbances in biomolecules. For instance, it has been observed that blue visible light from emitting diodes (LEDs) produces severe damage in murine cone photoreceptor-derived cells, and it can be even more harmful for some organisms than UV radiation. Recently, it has been found that the exposure of proteins to green and red light produces conformational changes, considerably increasing their cohesion enthalpies. This is presumably due to the strengthening of the hydrogen bonds and the formation of new ones. Therefore, it seems that visible light acts contrary to what it is observed for UV-C: instead of unfolding the proteins it folds them further, halting the damage produced by UV-C. This can be understood if we consider the modification of the folding energy-landscape; visible light induces the descent of the proteins into deeper states impeding the unfolding produced by UV-C. Copyright © 2016 Elsevier B.V. All rights reserved.

The ultraviolet radiation environment of pollen and its effect on pollen germination

NASA Technical Reports Server (NTRS)

1981-01-01

The damage to pollen caused by natural ultraviolet radiation was investigated. Experimental and literature research into the UV radiation environment is reported. Viability and germination of wind and insect pollinated species were determined. Physiological, developmental, and protective factors influencing UV sensitivity of binucleate, advanced binucleate, and trinucleate pollen grains are compared.

Ultraviolet Radiation Dose National Standard of México

NASA Astrophysics Data System (ADS)

Cardoso, R.; Rosas, E.

2006-09-01

We present the Ultraviolet (UV) Radiation Dose National Standard for México. The establishment of this measurement reference at Centro Nacional de Metrología (CENAM) eliminates the need of contacting foreign suppliers in the search for traceability towards the SI units when calibrating instruments at 365 nm. Further more, the UV Radiation Dose National Standard constitutes a highly accurate and reliable source for the UV radiation dose measurements performed in medical and cosmetic treatments as in the the food and pharmaceutics disinfection processes, among other.

Effects of near-ultraviolet light on mutations, intragenic and intergenic recombinations in Saccharomyces cerevisiae.

PubMed

Machida, I; Saeki, T; Nakai, S

1986-03-01

The effects of far (254 nm) and near (290-350 nm) ultraviolet (UV) light on mutations, intragenic and intergenic recombinations were compared in diploid strains of Saccharomyces cerevisiae. At equivalent survival levels there was not much difference in the induction of nonsense and missense mutations between far- and near-UV radiations. However, frameshift mutations were induced more frequently by near-UV than by far-UV radiation. Near-UV radiation induced intragenic recombination (gene conversion) as efficiently as far-UV radiation and the induced levels were similar in both radiations at equitoxic doses. A strikingly higher frequency was observed for the intergenic recombination induced by near-UV radiation than by far-UV radiation when compared at equivalent survival levels. Photoreactivation reduced the frequency only slightly in far-UV induced intergenic recombination and not at all in near-UV induction. These results indicate that near-UV damage involves strand breakage in addition to pyrimidine dimers and other lesions induced, whereas far-UV damage consists largely of photoreactivable lesions, pyrimidine dimers, and near-UV induced damage is more efficient for the induction of crossing-over.

ULTRAVIOLET RADIATION AND ARSENIC INTERACTIONS: EFFECTS ON CLADOCERANS

EPA Science Inventory

The effects of arsenic and ultraviolet radiation (UV) on cladocerans have been examined separately, however the interaction of these two stresses has not been explored. Potential synergism between these two stresses is possible as arsenic is known to inhibit repair of UV induced ...

Quality attributes of starfruit (Averrhoa carambola L.) juice treated with ultraviolet radiation.

PubMed

Bhat, Rajeev; Ameran, Suhaida Binti; Voon, Han Ching; Karim, A A; Tze, Liong Min

2011-07-15

Starfruit juice were exposed to ultraviolet (UV-C) light for 0, 30 and 60min at room temperature (25±1°C). On exposure, the titratable acidity significantly decreased, while the decrease in °Brix and pH were not significant. With regard to colorimetric parameters, L(∗) value increased significantly with a subsequent decrease in a(∗) and b(∗) values corresponding to UV treatment time. Except for the ascorbic acid, other antioxidants measured (% DPPH inhibition, total phenols, flavonols, flavonoids and antioxidant capacity) showed enhancement on expsoure to UV (significant at 60min). Microbial studies showed reduction in APC, yeasts and mould counts by 2-log cycle on UV treatments. These results supports the application of UV as a measure of non-thermal and physical food preservation technique for starfruit juice that can be explored commercially to benefit both the producers and consumers. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of prestorage UV-A, -B, and -C radiation on fruit quality and anthocyanin of 'Duke' blueberries during cold storage.

PubMed

Nguyen, Chau T T; Kim, Jeongyun; Yoo, Kil Sun; Lim, Sooyeon; Lee, Eun Jin

2014-12-17

Ultraviolet (UV)-A, -B, and -C were radiated to full-ripe blueberries (cv. 'Duke'), and their effects on fruit qualities and phytonutrients during subsequent cold storage were investigated. The blueberries were exposed to each UV light at 6 kJ/m(2) and then stored at 0 °C for 28 days. Weight loss and decay of the fruits after UV treatment were significantly decreased during the cold storage. The total phenolics and antioxidant activities of blueberries after UV-B and -C treatments were always higher than those of the control and UV-A treatment. Individual anthocyanins were markedly increased during the 3 h after the UV-B and -C treatments. The correlation matrix between total phenolics, anthocyanins, and antioxidant activity measured by the 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) assay indicated a significantly close correlation with the individual anthocyanin contents. It was confirmed that the prestorage treatments of UV-B and -C increased the storability and phytochemical accumulation of the full-ripe 'Duke' blueberries during cold storage.

The effects of ultraviolet radiation on photosynthetic performance, growth and sunscreen compounds in aeroterrestrial biofilm algae isolated from building facades.

PubMed

Karsten, U; Lembcke, S; Schumann, R

2007-03-01

The effects of artificial ultraviolet radiation [UVR; 8 W m(-2) ultraviolet-A (UVA), 0.4 W m(-2) ultraviolet-B (UVB)] on photosynthetic performance, growth and the capability to synthesise mycosporine-like amino acids (MAAs) was investigated in the aeroterrestrial green algae Stichococcus sp. and Chlorella luteoviridis forming biofilms on building facades, and compared with the responses of two green algae, from soil (Myrmecia incisa) and brackish water (Desmodesmus subspicatus). All species exhibited decreasing quantum efficiency (Fv/Fm) after 1-3 days exposure to UVR. After 8-12 days treatment, however, all aeroterrestrial isolates exhibited full recovery under UVA and UVA/B. In contrast, D. subspicatus showed only 80% recovery after treatment with UVB. While Stichococcus sp. and C. luteoviridis exhibited a broad tolerance in growth under all radiation conditions tested, M. incisa showed a significant decrease in growth rate after exposure to UVA and UVA/B. Similarly D. subspicatus grew with a reduced rate under UVA, but UVA/B led to full inhibition. Using HPLC, an UV-absorbing MAA (324 nm-MAA) was identified in Stichococcus sp. and C. luteoviridis. While M. incisa contained a specific 322 nm-MAA, D. subspicatus lacked any trace of such compounds. UV-exposure experiments indicated that all MAA-containing species are capable of synthesizing and accumulating these compounds, thus supporting their function as an UV-sunscreen. All data well explain the conspicuous ecological success of aeroterrestrial green algae in biofilms on facades. Biosynthesis and accumulation of MAAs under UVR seem to result in a reduced UV-sensitivity of growth and photosynthesis, which consequently may enhance survival in the environmentally harsh habitat.

Photoenhanced toxicity of a carbamate insecticide to early life stage anuran amphibians

USGS Publications Warehouse

Zaga, A.; Little, E.E.; Rabeni, C.F.; Ellersieck, Mark R.

1998-01-01

Aican clawed frog (Xenopus laevis) and gray tree frog (Hyla versicolor) embryos and tadpoles were exposed to sublethal levels of carbaryl, a broad-spectrum insecticide, and ultraviolet radiation to determine interactive and sublethal effects. Ultraviolet intensity (UV-B [285–320 nm] plus UV-A [321–400 nm]) was controlled with various types of plastic filters and quantified with a scanning spectroradiometer. Significant differences in swimming activity and mortality of both species were evident during the 96-h experiments. Ultraviolet-B radiation alone and carbaryl in the presence of UV-B significantly decreased swimming activity of both species. As little as 1.5% intensity of ambient solar UV-B radiation photoactivated carbaryl. Toxicity of 7.5 mg/L carbaryl increased by 10-fold in the presence of UV-B in all species and life stages tested. Our results indicate that photoenhancement by solar UV-B radiation should be considered when evaluating the toxicity of contaminants to amphibians and other organisms.

Quantifying the effects of corn growth and physiological responses to Ultraviolet-B radiation for modeling

USDA-ARS?s Scientific Manuscript database

To understand the consequences of rising levels of Ultraviolet-B (UV-B) radiation on maize (Zea mays L.), two experiments were conducted using sunlit plant growth chambers at a wide range UV-B radiation. Maize cultivars Terral-2100 and DKC 65-44 were grown in 2003 and 2008, respectively, at four le...

The linear polarization of 3C 345 in the ultraviolet

NASA Technical Reports Server (NTRS)

Dolan, Joseph F.; Boyd, Patricia T.; Wolinski, Karen G.; Smith, Paul S.; Impey, C. D.; Bless, Robert C.; Nelson, M. J.; Percival, J. W.; Taylor, M. J.; Elliot, J. L.

1994-01-01

The linear polarization of 3C 345, a superluminal radio source and OVV quasar, was observed in two bandpasses in the ultraviolet (centered at 2160 A and 2770 A) in 1993 April using the High Speed Photometer on the Hubble Space Telescope. The quasar is significantly polarized in the UV (p greater than 5%). Ground-based polarimetry was obtained 11 days later, but a difference in the position angle between the observations in the visible and those in the UV indicate that the magnitude of the polarization of 3C 345 may have changed over that time. If the two observation sets represent the same state of spectral polarization, then the large UV flux implies that either the polarization of the synchrotron continuum must stop decreasing in the UV, or that there is an additional source of polarized flux in the ultraviolet. Only if the UV observations represent a spectral polarization state with the same position angle in the visible seen previously in 3C 345 can the polarized flux be represented by a single power law consistent with the three-component model of Smith et al. This model consists of a polarized synchrotron component, an unpolarized component from the broad-line region, and an unpolarized component attributed to thermal radiation from an optically thick accretion disk. Additional simultaneous polarimetry in the UV and visible will be required to further constrain models of the continuum emission processes in 3C 345 and determine if the UV polarized flux is synchrotron in origin.

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

Wavelength of ultraviolet radiation that enhances onset of clinical infectious bovine keratoconjunctivitis

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

Kopecky, K.E.; Pugh, G.W. Jr.; Hughes, D.E.

1980-09-01

Cellulose acetate filtered ultraviolet (uv) radiation and unfiltered uv radiation were used on calves that were subsequently challenge exposed with Moraxella bovis. The onset, course, and severity of infectious bovine keratoconjunctivitis (IBK) were studied. Ten calves irradiated with unfiltered uv had the disease 1 to 2 days after M bovis challenge exposure. Ten calves irradiated with filtered uv and 10 calves not irradiated manifested IBK in a similar manner. Evidence is presented to support the contention that the wavelengths (around 270 nm) which are eliminated by cellulose acetate enhance the course of IBK. The effects on IBK of environmentally increasedmore » solar uv radiation is also discussed.« less

How does solar ultraviolet-B radiation improve drought tolerance of silver birch (Betula pendula Roth.) seedlings?

PubMed

Robson, T Matthew; Hartikainen, Saara M; Aphalo, Pedro J

2015-05-01

We hypothesized that solar ultraviolet (UV) radiation would protect silver birch seedlings from the detrimental effects of water stress through a coordinated suite of trait responses, including morphological acclimation, improved control of water loss through gas exchange and hydraulic sufficiency. To better understand how this synergetic interaction works, plants were grown in an experiment under nine treatment combinations attenuating ultraviolet-A and ultraviolet-B (UVB) from solar radiation together with differential watering to create water-deficit conditions. In seedlings under water deficit, UV attenuation reduced height growth, leaf production and leaf length compared with seedlings receiving the full spectrum of solar radiation, whereas the growth and morphology of well-watered seedlings was largely unaffected by UV attenuation. There was an interactive effect of the treatment combination on water relations, which was more apparent as a change in the water potential at which leaves wilted or plants died than through differences in gas exchange. This suggests that changes occur in the cell wall elastic modulus or accumulation of osmolites in cells under UVB. Overall, the strong negative effects of water deficit are partially ameliorated by solar UV radiation, whereas well-watered silver birch seedlings are slightly disadvantaged by the solar UV radiation they receive. © 2014 John Wiley & Sons Ltd.

Lanthanum (III) regulates the nitrogen assimilation in soybean seedlings under ultraviolet-B radiation.

PubMed

Huang, Guangrong; Wang, Lihong; Zhou, Qing

2013-01-01

Ultraviolet-B (UV-B, 280-320 nm) radiation has seriously affected the growth of plants. Finding the technology/method to alleviate the damage of UV-B radiation has become a frontal topic in the field of environmental science. The pretreatment with rare earth elements (REEs) is an effective method, but the regulation mechanism of REEs is unknown. Here, the regulation effects of lanthanum (La(III)) on nitrogen assimilation in soybean seedlings (Glycine max L.) under ultraviolet-B radiation were investigated to elucidate the regulation mechanism of REEs on plants under UV-B radiation. UV-B radiation led to the inhibition in the activities of the key enzymes (nitrate reductase, glutamine synthetase, glutamate synthase) in the nitrogen assimilation, the decrease in the contents of nitrate and soluble proteins, as well as the increase in the content of amino acid in soybean seedlings. The change degree of UV-B radiation at the high level (0.45 W m(-2)) was higher than that of UV-B radiation at the low level (0.15 W m(-2)). The pretreatment with 20 mg L(-1) La(III) could alleviate the effects of UV-B radiation on the activities of nitrate reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase, promoting amino acid conversion and protein synthesis in soybean seedlings. The regulation effect of La(III) under UV-B radiation at the low level was better than that of UV-B radiation at the high level. The results indicated that the pretreatment with 20 mg L(-1) La(III) could alleviate the inhibition of UV-B radiation on nitrogen assimilation in soybean seedlings.

Assessment of the impact of increased solar ultraviolet radiation upon marine ecosystems

NASA Technical Reports Server (NTRS)

Worrest, R. C.; Vandyke, H.

1978-01-01

Reduction of the earth's ozone layer, with a resultant increase in transmission of solar ultraviolet radiation in the 290 to 320nm waveband (UV-B), via space shuttle operations through the stratosphere is considered. It is shown that simulated solar ultraviolet radiation can, under experimental conditions, detrimentally affect the marine organisms that form the base of the food web of oceanic and estuarine ecosystems. Whether a small increase in biologically harmful ultraviolet radiation might overwhelm these mechanisms and produce changes that will have damaging consequences to the biosphere is discussed. The potential for irreversible damage to the productivity, structure and/or functioning of a model estuarine ecosystem by increased UV-B radiation and whether these ecosystems are highly stable or amenable to adaptive change is studied. Data are provided to assess the potential impact upon marine ecosystems if space shuttle operations contribute to a reduction of the stratospheric ozone layer and the sensitivity of key community components to increased UV-B radiation is examined.

Measurement of the solar ultraviolet radiation at ground level in Bangi, Malaysia

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

Aljawi, Ohoud; Gopir, Geri; Duay, Abdul Basit

2015-04-24

Understanding the amount of ultraviolet (UV) radiation received by human, plant, and animal organisms near the earth’s surface is important to a wide range of fields such as cancer research, agriculture and forestry. The solar ultraviolet spectral irradiance at ground level was measured using the Avantes spectrometer for the period of January to March 2014 at Bangi (2°55´N, 101°46´E, 50 m above sea level) in Malaysia. These data were used to estimate the diurnal variation of UV irradiance (300 – 400 nm). The maximum irradiance of UV radiation was 45 W m{sup −2} on horizontal surface. The maximum irradiance ofmore » UV received in the local noon time, and the minimum values of UV irradiance was received in the local morning time. It is found a bigger value of UV radiation was observed on clear sky in January. The estimation of daily flux average of UV irradiance was (921± 91) kJ m{sup −2}.« less

Accelerated Solar-UV Test Chamber

NASA Technical Reports Server (NTRS)

Gupta, A.; Laue, E. G.

1984-01-01

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

An ESR study of the UV degradation of FEP

NASA Technical Reports Server (NTRS)

George, G. A.; Hill, D. J. T.; Odonnell, J. H.; Pomery, P. J.; Rasoul, F.

1992-01-01

Spacecraft in low earth orbit are subjected to significant levels of high energy radiation, including ultraviolet (UV) and visible ultraviolet (VUV) wavelengths. The effects of UV radiation are enhanced over those at the surface of the earth, where the only incident wavelengths are greater than 290 nm. In low earth orbit the incident UV wavelengths extend below 290 nm into the VUV region, where the Lyman alpha-emissions of atomic hydrogen occur at 121 nm. In addition to electromagnetic radiation, in low earth orbit polymer materials may also be subjected to atomic oxygen particle radiation, which will result in direct oxidation of the polymer.

Modeling the survivability of brucella to exposure of Ultraviolet radiation and temperature

NASA Astrophysics Data System (ADS)

Howe, R.

Accumulated summation of daily Ultra Violet-B (UV-B = 290? to 320 ? ) data? from The USDA Ultraviolet Radiation Monitoring Program show good correlation (R^2 = 77%) with daily temperature data during the five month period from February through June, 1998. Exposure of disease organisms, such as brucella to the effects of accumulated UV-B radiation, can be modeled for a 5 month period from February through June, 1998. Estimates of a lethal dosage for brucell of UV-B in the environment is dependent on minimum/maximum temperature and Solar Zenith Angle for the time period. The accumulated increase in temperature over this period also effects the decomposition of an aborted fetus containing brucella. Decomposition begins at some minimum daily temperature at 27 to 30 degrees C and peaks at 39 to 40C. It is useful to view the summation of temperature as a threshold for other bacteria growth, so that accumulated temperature greater than some value causes decomposition through competition with other bacteria and brucella die from the accumulated effects of UV-B, temperature and organism competition. Results of a study (Cook 1998) to determine survivability of brucellosis in the environment through exposure of aborted bovine fetuses show no one cause can be attributed to death of the disease agent. The combination of daily increase in temperature and accumulated UV-B radiation reveal an inverse correlation to survivability data and can be modeled as an indicator of brucella survivability in the environment in arid regions.

QUANTIFYING ULTRAVIOLET RADIATION DOSE RELATIVE TO WETLAND HABITAT VARIABLES FOR THE ASSESSMENT OF RISK TO AMPHIBIANS

EPA Science Inventory

Ultraviolet B radiation (UV-B) has increased globally over the last several decades due to reduction of stratospheric ozone. UV-B may also increase when climate change alters cloud cover, rainfall, and distributions of vegetation. In aquatic systems, these factors can also intera...

[UV-induced DNA damage and protective effects of antioxidants on DNA damage in human lens epithelial cells studied with comet assay].

PubMed

Wu, Zhi-hong; Wang, Mian-rong; Yan, Qi-chang; Pu, Wei; Zhang, Jin-song

2006-11-01

To investigate the mechanism of UV-induced DNA damage and repair and the protective effects of antioxidants on DNA damage in human lens epithelial cells. Human lens epithelial cells were irradiated at UV-doses 0.0 (control group), 2.5, 5.0, 7.5, 10.0 mJ/cm(2) (treated group 1 - 4). The amounts of DNA single strand breaks (SSB) were measured with the alkaline comet assay (CA). The spontaneous repair of DNA SSB after exposure to UV at 10.0 mJ/cm(2) was also determined in human lens epithelial cells. Human lens epithelial cells were treated with different concentration of VitaminC (VitC), taurine, superoxide dismutase (SOD) and epigallocatechin gallate (EGCG) before and after ultraviolet radiation, the effects of antioxidants on DNA damage was examined with alkaline comet assay. The amount of DNA SSB in control group and treated groups 1 - 4 showed increased tendency, was dose-dependent to the dose of UV irradiation, the differences of DNA SSB in 5 group were significantly (P < 0.01). UV-induced DNA SSB at 10.0 mJ/cm(2) in human lens epithelial cells, the half repair time was 60 minutes. Human lens epithelial cells were treated with different concentrations of taurine, SOD and EGCG before ultraviolet radiation. The differences of DNA damage in control and various antioxidant treated groups was statistically significant (F = 6.591, 13.542, 4.626 in cells treated with taurine, SOD and EGCG, respectively, P < 0.01), the difference of VitC effect on DNA in control and treated group were not significantly (F = 1.451, P > 0.05). Human lens epithelial cells were treated with different concentration of VitC, taurine, SOD and EGCG after ultraviolet radiation. The differences of DNA damage between the control and treated group were statistically significant (F = 6.571, 4.810, 6.824, 9.182 in cells treated with VitC, taurine, SOD and EGCG, respectively, P < 0.01). The differences of protective effects on DNA damage in these four different kinds of antioxidants added before UV irradiation were statistically significant (P < 0.01). The differences of protective effects on DNA damage in these four different kinds of antioxidant added after UV irradiation were not significantly (P > 0.05). UV irradiation has a dose-dependent effect on the DNA SSB of lens epithelial cells. Exogenesis VitC, taurine, SOD, EGCG possess protective effective to UV-induced DNA damage. SOD is one of the most powerful antioxidants if added before the UV irradiation and followed by EGCG, taurine and VitC orderly. Four kinds of antioxidants show no apparently differences added after UV-irradiation. SOD and EGCG both are powerful antioxidants.

The interaction between abiotic photodegradation and microbial decomposition under ultraviolet radiation.

PubMed

Wang, Jing; Liu, Lingli; Wang, Xin; Chen, Yiwei

2015-05-01

Elevated ultraviolet (UV) radiation has been demonstrated to stimulate litter decomposition. Despite years of research, it is still not fully understood whether the acceleration in litter degradation is primarily attributed to abiotic photodegradation or the combined effects of abiotic photodegradation and microbial decomposition. In this study, we used meta-analysis to synthesize photodegradation studies and compared the effects of UV radiation on litter decomposition between abiotic and biotic conditions. We also conducted a microcosm experiment to assess the effects of UV radiation on litter biodegradability and microbial activity. Overall, our meta-analysis found that under abiotic photodegradation, UV radiation reduced the remaining litter mass by 1.44% (95% CI: 0.85% to 2.08%), did not affect the remaining lignin and increased the dissolved organic carbon (DOC) concentration by 14.01% (1.49-23.67%). Under combined abiotic photodegradation and microbial decomposition, UV radiation reduced the remaining litter mass and lignin by 1.60% (0.04-3.58%) and 16.07% (9.27-24.23%), respectively, but did not alter DOC concentration. UV radiation had no significant impact on soil microbial biomass carbon (MBC), but it reduced microbial respiration by 44.91% (2.26-78.62%) and altered the composition of the microbial community. In addition, UV radiation reduced nitrogen (N) immobilization by 19.44% (4.77-37.92%). Our microcosm experiment further indicated that DOC concentration and the amount of respired C in UV-treated litter increased with UV exposure time, suggesting that longer UV exposure resulted in greater biodegradability. Overall, our study suggested that UV exposure could increase litter biodegradability by increasing the microbial accessibility of lignin, as well as the labile carbon supply to microbes. However, the remaining litter mass was not different between the abiotic and biotic conditions, most likely because the positive effect of UV radiation on litter biodegradability was offset by its negative effect on microbial activity. Our results also suggested that UV radiation could alter the N cycle during decomposition, primarily by inhibiting N immobilization. © 2014 John Wiley & Sons Ltd.

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.

An Autonomous System for Experimental Evolution of Microbial Cultures: Test Results Using Ultraviolet-C Radiation and Escherichia Coli.

NASA Technical Reports Server (NTRS)

Ouandji, Cynthia; Wang, Jonathan; Arismendi, Dillon; Lee, Alonzo; Blaich, Justin; Gentry, Diana

2017-01-01

At its core, the field of microbial experimental evolution seeks to elucidate the natural laws governing the history of microbial life by understanding its underlying driving mechanisms. However, observing evolution in nature is complex, as environmental conditions are difficult to control. Laboratory-based experiments for observing population evolution provide more control, but manually culturing and studying multiple generations of microorganisms can be time consuming, labor intensive, and prone to inconsistency. We have constructed a prototype, closed system device that automates the process of directed evolution experiments in microorganisms. It is compatible with any liquid microbial culture, including polycultures and field samples, provides flow control and adjustable agitation, continuously monitors optical density (OD), and can dynamically control environmental pressures such as ultraviolet-C (UV-C) radiation and temperature. Here, the results of the prototype are compared to iterative exposure and survival assays conducted using a traditional hood, UV-C lamp, and shutter system.

Autonomous portable solar ultraviolet spectroradiometer (APSUS) - a new CCD spectrometer system for localized, real-time solar ultraviolet (280-400 nm) radiation measurement.

PubMed

Hooke, Rebecca; Pearson, Andy; O'Hagan, John

2014-01-01

Terrestrial solar ultraviolet (UV) radiation has significant implications for human health and increasing levels are a key concern regarding the impact of climate change. Monitoring solar UV radiation at the earth's surface is therefore of increasing importance. A new prototype portable CCD (charge-coupled device) spectrometer-based system has been developed that monitors UV radiation (280-400 nm) levels at the earth's surface. It has the ability to deliver this information to the public in real time. Since the instrument can operate autonomously, it is called the Autonomous Portable Solar Ultraviolet Spectroradiometer (APSUS). This instrument incorporates an Ocean Optics QE65000 spectrometer which is contained within a robust environmental housing. The APSUS system can gather reliable solar UV spectral data from approximately April to October inclusive (depending on ambient temperature) in the UK. In this study the new APSUS unit and APSUS system are presented. Example solar UV spectra and diurnal UV Index values as measured by the APSUS system in London and Weymouth in the UK in summer 2012 are shown. © 2014 Crown copyright. Photochemistry and Photobiology © 2014 The American Society of Photobiology. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland and Public Health England.

Comparison of microbiological loads and physicochemical properties of raw milk treated with single-/multiple-cycle high hydrostatic pressure and ultraviolet-C light

NASA Astrophysics Data System (ADS)

Hu, Guanglan; Zheng, Yuanrong; Wang, Danfeng; Zha, Baoping; Liu, Zhenmin; Deng, Yun

2015-07-01

The effects of ultraviolet-C radiation (UV-C, 11.8 W/m2), single-cycle and multiple-cycle high hydrostatic pressure (HHP at 200, 400 or 600 MPa) on microbial load and physicochemical quality of raw milk were evaluated. Reductions of aerobic plate count (APC) and coliform count (CC) by HHP were more than 99.9% and 98.7%, respectively. Inactivation efficiency of microorganisms increased with pressure level. At the same pressure level, two-cycle treatments caused lower APC, but did not show CC differences compared with single-cycle treatments. Reductions of APC and CC by UV-C were somewhere between 200 MPa and 400/600 MPa. Both HHP and UV-C significantly decreased lightness and increased pH, but did not change soluble solids content and thiobarbituric acid-reactive substances' values. Two 2.5 min cycles of HHP at 600 MPa caused minimum APC and CC, and maximum conductivity. Compared with HHP, UV-C markedly increased protein oxidation and reduced darkening.

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.

DISTRIBUTION PATTERNS OF LENTIC-BREEDING AMPHIBIANS IN RELATION OF ULTRAVIOLET RADIATION EXPOSURE IN WESTERN NORTH AMERICA

EPA Science Inventory

An increase in ultraviolet (UV-B) radiation has been posited to be a potential factor in the decline of some amphibian population...Much more work is still needed to determine whether UV-B, either alone or in concert with other factors, is causing widespread population losses in ...

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...

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.

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.

The ultraviolet and visible spectrum of the polycyclic aromatic hydrocarbon C10H8(+) - Possible contributions to the diffuse interstellar bands and to the ultraviolet-visible extinction

NASA Technical Reports Server (NTRS)

Salama, F.; Allamandola, L. J.

1992-01-01

The properties of the cation of the PAH naphthalene (C10H8(+)) isolated in inert gas matrices under conditions relevant to astrophysical environments are described. The band at 6741 A is the strongest and falls close to the weak 6742 A diffuse interstellar bands (DIBs). Five other weaker bands also fall remarkably close to the positions of known DIBs. A very intense and broad continuum extended from the UV to the visible, which seems to be associated with the ion, is reported. The molar absorption coefficient at the peak of the continuum is 2.0 x 10 exp 6 cu dm/mol cm. If a continuum is a general property of PAH cations, this characteristic will have a strong impact on the understanding of how PAHs convert interstellar UV and visible radiation into IR radiation.

The endogenous hormones in soybean seedlings under the joint actions of rare earth element La(III) and ultraviolet-B stress.

PubMed

Peng, Qi; Zhou, Qing

2009-12-01

The dynamic state of endogenous hormone content in soybean seedlings was investigated for a further demonstration of alleviating the damage of the ultraviolet ultraviolet-B (UV-B) radiation in the La(III)-treated soybean seedlings under UV-B stress. Using hydroponics culture, the effects of lanthanum(III) on the contents of endogenous hormone under elevated ultraviolet-B radiation (280–320 nm) was studied. The results showed that the content of indole-3-acetic acid (IAA) in soybean seedlings decreased initially and then increased when the seedlings underwent UV-B treatment during the stress and convalescent period; this was compared with a control; acetic acid oxidase (IAAO) activity increased at first (first to fifth day) and then decreased (sixth to 11th day). A similar change of abscisic acid content and IAAO content in soybean seedlings occurred; gibberellic acid (GA) content decreased during the experiment compared with control. The content of IAA and GA in soybean seedlings with La(III) + UV-B treatment was higher than those of UV-B treatment; IAAO activity and GA content in soybean seedlings with La (III) + UV-B treatment were lower than those of UV-B treatment. It suggested that the regulative effect of La(III) at the optimum concentration on endogenous hormone improved the ability of plant stress resistance, and its protective effect against low UV-B radiation was superior to high UV-B radiation. The defensive effect of La(III) on soybean seedlings under UV-B stress was carried out on the layer of defense system.

Cumulative effects from repeated exposures to ultraviolet radiation

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

Kaidbey, K.H.; Kligman, A.M.

Repeated exposures to subliminal doses of UVR, given at 24-hr intervals, resulted in a lowering of the erythema threshold dose. At erythemogenically equivalent doses, UV-A was the most effective and UV-C the least. A similar and more pronounced effect was observed following repeated exposures to subthreshold doses of UV-A and topically applied 8-methoxypsoralen. These findings provide quantitative evidence for the cumulative nature of acute UVR damage in human skin.

The Molecular and Physiological Responses of Physcomitrella patens to Ultraviolet-B Radiation1[W][OA

PubMed Central

Wolf, Luise; Rizzini, Luca; Stracke, Ralf; Ulm, Roman; Rensing, Stefan A.

2010-01-01

Ultraviolet-B (UV-B) radiation present in sunlight is an important trigger of photomorphogenic acclimation and stress responses in sessile land plants. Although numerous moss species grow in unshaded habitats, our understanding of their UV-B responses is very limited. The genome of the model moss Physcomitrella patens, which grows in sun-exposed open areas, encodes signaling and metabolic components that are implicated in the UV-B response in flowering plants. In this study, we describe the response of P. patens to UV-B radiation at the morphological and molecular levels. We find that P. patens is more capable of surviving UV-B stress than Arabidopsis (Arabidopsis thaliana) and describe the differential expression of approximately 400 moss genes in response to UV-B radiation. A comparative analysis of the UV-B response in P. patens and Arabidopsis reveals both distinct and conserved pathways. PMID:20427465

Ultraviolet Absorption Induces Hydrogen-Atom Transfer in G⋅C Watson-Crick DNA Base Pairs in Solution.

PubMed

Röttger, Katharina; Marroux, Hugo J B; Grubb, Michael P; Coulter, Philip M; Böhnke, Hendrik; Henderson, Alexander S; Galan, M Carmen; Temps, Friedrich; Orr-Ewing, Andrew J; Roberts, Gareth M

2015-12-01

Ultrafast deactivation pathways bestow photostability on nucleobases and hence preserve the structural integrity of DNA following absorption of ultraviolet (UV) radiation. One controversial recovery mechanism proposed to account for this photostability involves electron-driven proton transfer (EDPT) in Watson-Crick base pairs. The first direct observation is reported of the EDPT process after UV excitation of individual guanine-cytosine (G⋅C) Watson-Crick base pairs by ultrafast time-resolved UV/visible and mid-infrared spectroscopy. The formation of an intermediate biradical species (G[-H]⋅C[+H]) with a lifetime of 2.9 ps was tracked. The majority of these biradicals return to the original G⋅C Watson-Crick pairs, but up to 10% of the initially excited molecules instead form a stable photoproduct G*⋅C* that has undergone double hydrogen-atom transfer. The observation of these sequential EDPT mechanisms across intermolecular hydrogen bonds confirms an important and long debated pathway for the deactivation of photoexcited base pairs, with possible implications for the UV photochemistry of DNA. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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...

EFFECTS OF ULTRAVIOLET-B IRRADIANCE IN SOYBEAN. 6. INFLUENCE OF PHOSPHORUS NUTRITION ON GROWTH AND FLAVONIID CONTENT

EPA Science Inventory

Soybeans Glycine max Essex were hydroponically grown in a greenhouse at 2 levels of ultraviolet-B(UV-B) radiation and 4 levels of P. Plants were grown in each treatment combination to the complete expansion of the 4th trifoliolate leaf. UV-B radiation and reduced P supply general...

Protective effect of rare earth against oxidative stress under ultraviolet-B radiation.

PubMed

Wang, Lihong; Huang, Xiaohua; Zhou, Qing

2009-04-01

The effects of lanthanum (III) (La(III)) in protecting soybean leaves against oxidative stress induced by ultraviolet-B (UV-B) radiation were investigated. The increase in contents of hydrogen peroxide (H(2)O(2)) and superoxide (O2*-) due to UV-B radiation suggested oxidative stress. The increase in the content of malondialdehyde (MDA) and the decrease in the index of unsaturated fatty acid (IUFA) indicated oxidative damage on cell membrane induced by UV-B radiation. La(III) partially reversed UV-B-radiation-induced damage of plant growth. The reduction in the contents of H(2)O(2), O2*-, and MDA and increase in the content of IUFA, compared with UV-B treatment, also indicated that La(III) alleviated the oxidative damage induced by UV-B radiation. The increase in the activities of superoxide dismutase and peroxidase and the contents of ascorbate, carotenoids, and flavonoids were observed in soybean leaves with La(III) + UV-B treatment, compared with UV-B treatment. Our data suggested that La(III) could protect soybean plants from UV-B-radiation-induced oxidative stress by reacting with reactive oxygen species directly or by improving the defense system of plants.

Spectral properties of plant leaves pertaining to urban landscape design of broad-spectrum solar ultraviolet radiation reduction

NASA Astrophysics Data System (ADS)

Yoshimura, Haruka; Zhu, Hui; Wu, Yunying; Ma, Ruijun

2010-03-01

Human exposure to harmful ultraviolet (UV) radiation has important public health implications. Actual human exposure to solar UV radiation depends on ambient UV irradiance, and the latter is influenced by ground reflection. In urban areas with higher reflectivity, UV exposure occurs routinely. To discover the solar UV radiation regulation mechanism of vegetation, the spectral reflectance and transmittance of plant leaves were measured with a spectrophotometer. Typically, higher plants have low leaf reflectance (around 5%) and essentially zero transmittance throughout the UV region regardless of plant species and seasonal change. Accordingly, incident UV radiation decreases to 5% by being reflected and is reduced to zero by passing through a leaf. Therefore, stratified structures of vegetation are working as another terminator of UV rays, protecting whole terrestrial ecosystems, while vegetation at waterfronts contributes to protect aquatic ecosystems. It is possible to protect the human population from harmful UV radiation by urban landscape design of tree shade and the botanical environment. Even thin but uniformly distributed canopy is effective in attenuating UV radiation. To intercept diffuse radiation, UV screening by vertical structures such as hedges should be considered. Reflectivity of vegetation is around 2%, as foliage surfaces reduce incident UV radiation via reflection, while also eliminating it by transmittance. Accordingly, vegetation reduces incident UV radiation to around 2% by reflection. Vegetation influence on ambient UV radiation is broad-spectrum throughout the UV region. Only trees provide cool UV protective shade. Urban landscapes aimed at abating urban heat islands integrated with a reduction of human UV over-exposure would contribute to mitigation of climate change.

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

Key Words: Ultraviolet radiation,Standard Erythema Dose(SED), Minimal Erythema Dose(MED), Sun Burns, Solar Dermatitis, Sun Burned Disease, DNA Damage,Cell Damage, Antiradiation UV Vaccine, Immune-Prophylaxis of Sun Burned Diseases, Immune-Prophylaxis of Sun Burns, Immune-Therapy of Sun-Burned Disease and Sun Burns,Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), Toxic Epidermal Necrolysis(TEN). Introduction: High doses of UV generated by solar source and artificial sources create an exposure of mammals and other species which can lead to ultraviolet(UV)radiation- associated disease (including erythema, epilation, keratitis, etc.). UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm with 100 nm having been chosen arbitrarily as the boundary between non-ionizing and ionizing radiation, however EMR is a spectrum and UV can produce molecular ionization. UV radiation is conventionally categorized into 3 areas: UV-A (>315-400 nm),UV-B (>280-315 nm)and UV-C (>100-280 nm) [IARC,Working Group Reports,2005] An important consequence of stratospheric ozone depletion is the increased transmission of solar ultraviolet (UV)radiation to the Earth's lower atmosphere and surface. Stratospheric ozone levels have been falling, in certain areas, for the past several decades, so current surface ultraviolet-B (UV-B) radiation levels are thought to be close to their modern day maximum. [S.Madronich et al.1998] Overexposure of ultraviolet radiation a major cause of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) { collectively referred to as “non-melanoma" skin cancer (NMSC) and melanoma as well, with skin cancers being the most common cancer in North America. [Armstrong et al. 1993, Gallagher et al. 2005] Methods and Experimental Design: Our experiments and testing of a novel UV “Antiradiation Vaccine” have employed a wide variety of laboratory animals which include : Chinchilla rabbits, 11-12 months old, live weight 3.5-3.7 (n=11), Balb mice, 2-3 months old, live weight 20-22 g (n=33), Wistar rats, 3-4 months old, live weight 180-220 g(n=33). The studies were approved by the Animal Care and Use Committee for ethical animal research equivalent, at each institution. Seven rabbits, ten mice, eleven Wistar rats were vaccinated with a UV antiradiation vaccine. A second group of animals was used as biological control which received vaccine but no UV Radiation and a third group of animals was used as control without any interventions. Before and after UV Radiation, Vaccination with the UV antiradiation vaccine were provided 17 days prior to UV exposure. The animals were irradiated by a DRT-1 UV generator lamp. The dose of irradiation for laboratory, experimental animals was 10-12 * Standard Erythema Dose (SED) at L=283,7 Laboratory animals were placed in to the box with ventilation. Results: Ultraviolet irradiation of the skin was performed with high doses and causes an inflammation or erythema in all experimental animals. However the grade of skin damage and inflammation was significantly different between animals protected by vaccination and non-protected, non-vaccinated animals. Animals UV-irradiated, but who did not receive the antiradiation vaccine suffered from extensive UV skin burns of second or third degree (grade 2-3). However, animals protected with the UV antiradiation vaccine demonstrated much mild forms of skin cellular injury - mainly erythema, first degree skin burns and a few small patches with second degree skin burns (grade 1-2). Discussion: The severity of skin damage depended on area of exposed skin, time and dose of UV irradiation. Skin injury could be divided into 4 major grades: 1. Faint erythema with dry desquamation. 2. Moderate to severe erythema. 3. Severe erythema with blistering, moist desquamation. 4. Toxic epidermal necrolysis. Mild doses of UV radiation and ionizing radiation can induce cell death by apoptosis and 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.

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.

Optical Technologies for UV Remote Sensing Instruments

NASA Technical Reports Server (NTRS)

Keski-Kuha, R. A. M.; Osantowski, J. F.; Leviton, D. B.; Saha, T. T.; Content, D. A.; Boucarut, R. A.; Gum, J. S.; Wright, G. A.; Fleetwood, C. M.; Madison, T. J.

1993-01-01

Over the last decade significant advances in technology have made possible development of instruments with substantially improved efficiency in the UV spectral region. In the area of optical coatings and materials, the importance of recent developments in chemical vapor deposited (CVD) silicon carbide (SiC) mirrors, SiC films, and multilayer coatings in the context of ultraviolet instrumentation design are discussed. For example, the development of chemically vapor deposited (CVD) silicon carbide (SiC) mirrors, with high ultraviolet (UV) reflectance and low scatter surfaces, provides the opportunity to extend higher spectral/spatial resolution capability into the 50-nm region. Optical coatings for normal incidence diffraction gratings are particularly important for the evolution of efficient extreme ultraviolet (EUV) spectrographs. SiC films are important for optimizing the spectrograph performance in the 90 nm spectral region. The performance evaluation of the flight optical components for the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument, a spectroscopic instrument to fly aboard the Solar and Heliospheric Observatory (SOHO) mission, designed to study dynamic processes, temperatures, and densities in the plasma of the upper atmosphere of the Sun in the wavelength range from 50 nm to 160 nm, is discussed. The optical components were evaluated for imaging and scatter in the UV. The performance evaluation of SOHO/CDS (Coronal Diagnostic Spectrometer) flight gratings tested for spectral resolution and scatter in the DGEF is reviewed and preliminary results on resolution and scatter testing of Space Telescope Imaging Spectrograph (STIS) technology development diffraction gratings are presented.

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.

Satellite estimation of surface spectral ultraviolet irradiance using OMI data in East Asia

NASA Astrophysics Data System (ADS)

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

2017-12-01

Due to a strong influence to the human health and ecosystem environment, continuous monitoring of the surface ultraviolet (UV) irradiance is important nowadays. 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 UV irradiance estimation. Also UV index (UVI) is a simple parameter to show the strength of surface UV irradiance, therefore UVI has been widely utilized for the purpose of UV monitoring. In this study, we estimate surface UV irradiance at East Asia using realistic input based on OMI Total Ozone and reflectivity, and then validate this estimated comparing to UV irradiance from World Ozone and Ultraviolet Radiation Data Centre (WOUDC) data. In this work, we also try to develop our own retrieval algorithm for better estimation of surface irradiance. We use the Vector Linearized Discrete Ordinate Radiative Transfer (VLIDORT) model version 2.6 for our UV irradiance calculation. The input to the VLIDORT radiative transfer calculations are the total ozone column (TOMS V7 climatology), the surface albedo (Herman and Celarier, 1997) and the cloud optical depth. Based on these, the UV irradiance is calculated based on look-up table (LUT) approach. To correct absorbing aerosol, UV irradiance algorithm added climatological aerosol information (Arola et al., 2009). The further study, we analyze the comprehensive uncertainty analysis based on LUT and all input parameters.

Sources and measurement of ultraviolet radiation.

PubMed

Diffey, Brian L

2002-09-01

Ultraviolet (UV) radiation is part of the electromagnetic spectrum. The biological effects of UV radiation vary enormously with wavelength and for this reason the UV spectrum is further subdivided into three regions: UVA, UVB, and UVC. Quantities of UV radiation are expressed using radiometric terminology. A particularly important term in clinical photobiology is the standard erythema dose (SED), which is a measure of the erythemal effectiveness of a UV exposure. UV radiation is produced either by heating a body to an incandescent temperature, as is the case with solar UV, or by passing an electric current through a gas, usually vaporized mercury. The latter process is the mechanism whereby UV radiation is produced artificially. Both the quality (spectrum) and quantity (intensity) of terrestrial UV radiation vary with factors including the elevation of the sun above the horizon and absorption and scattering by molecules in the atmosphere, notably ozone, and by clouds. For many experimental studies in photobiology it is simply not practicable to use natural sunlight and so artificial sources of UV radiation designed to simulate the UV component of sunlight are employed; these are based on either optically filtered xenon arc lamps or fluorescent lamps. The complete way to characterize an UV source is by spectroradiometry, although for most practical purposes a detector optically filtered to respond to a limited portion of the UV spectrum normally suffices.

Emission characteristics of plasma based on xenon-rubidium bromide mixture

NASA Astrophysics Data System (ADS)

Heneral, A. A.; Avtaeva, S. V.

2017-10-01

Luminescence spectra of a longitudinal pulse-periodic discharge in xenon mixture with rubidium bromide vapors (Xe-RbBr) are studied experimentally at low pressures. The conditions leading to the appearance of intense bands of ultraviolet radiation of exciplex XeBr* molecules in the spectral interval between 200 and 400 nm are found. The highest yield of UV radiation of XeBr* molecules is achieved when the temperature of discharge-tube walls is equal to 750°C. A maximum power of UV radiation from the entire plasma volume as high as 4.8 W is obtained.

Toxicity of cobalt-complexed cyanide to Oncorhynchus mykiss, Daphnia magna, and Ceriodaphnia dubia: Potentiation by ultraviolet radiation and attenuation by dissolved organic carbon and adaptive UV tolerance

USGS Publications Warehouse

Little, Edward E.; Calfee, Robin D.; Theodorakos, Peter M.; Brown, Zoe Ann; Johnson, Craig A.

2007-01-01

BackgroundCobalt cyanide complexes often result when ore is treated with cyanide solutions to extract gold and other metals. These have recently been discovered in low but significant concentrations in effluents from gold leach operations. This study was conducted to determine the potential toxicity of cobalt-cyanide complexes to freshwater organisms and the extent to which ultraviolet radiation (UV) potentiates this toxicity. Tests were also conducted to determine if humic acids or if adaptation to UV influenced sensitivity to the cyanide complexes.MethodsRainbow trout (Oncorhynchus mykiss), Daphnia magna, and Ceriodaphnia dubia were exposed to potassium hexacyanocobaltate in the presence and absence of UV radiation, in the presence and absence of humic acids. Cyano-cobalt exposures were also conducted with C. dubia from cultures adapted to elevated UV.ResultsWith an LC50 concentration of 0.38 mg/L, cyanocobalt was over a 1000 times more toxic to rainbow trout in the presence of UV at a low, environmentally relevant irradiance level (4 μW/cm2 as UVB) than exposure to this compound in the absence of UV with an LC50 of 112.9 mg/L. Toxicity was immediately apparent, with mortality occurring within an hour of the onset of exposure at the highest concentration. Fish were unaffected by exposure to UV alone. Weak-acid dissociable cyanide concentrations were observed in irradiated aqueous solutions of cyanocobaltate within hours of UV exposure and persisted in the presence of UV for at least 96 hours, whereas negligible concentrations were observed in the absence of UV. The presence of humic acids significantly diminished cyanocobalt toxicity to D. magna and reduced mortality from UV exposure. Humic acids did not significantly influence survival among C. dubia. C. dubia from UV-adapted populations were less sensitive to metallocyanide compounds than organisms from unadapted populations.ConclusionsThe results indicate that metallocyanide complexes may pose a hazard to aquatic life through photochemically induced processes. Factors that decrease UV exposure such as dissolved organic carbon or increased pigmentation would diminish toxicity.

Ultraviolet damage to the eye revisited: eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear.

PubMed

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

2014-01-01

Ultraviolet (UV) radiation potentially damages the skin, the immune system, and structures of the eye. A useful UV sun protection for the skin has been established. Since a remarkable body of evidence shows an association between UV radiation and damage to structures of the eye, eye protection is important, but a reliable and practical tool to assess and compare the UV-protective properties of lenses has been lacking. Among the general lay public, misconceptions on eye-sun protection have been identified. For example, sun protection is mainly ascribed to sunglasses, but less so to clear lenses. Skin malignancies in the periorbital region are frequent, but usual topical skin protection does not include the lids. Recent research utilized exact dosimetry and demonstrated relevant differences in UV burden to the eye and skin at a given ambient irradiation. Chronic UV effects on the cornea and lens are cumulative, so effective UV protection of the eyes is important for all age groups and should be used systematically. Protection of children's eyes is especially important, because UV transmittance is higher at a very young age, allowing higher levels of UV radiation to reach the crystalline lens and even the retina. Sunglasses as well as clear lenses (plano and prescription) effectively reduce transmittance of UV radiation. However, an important share of the UV burden to the eye is explained by back reflection of radiation from lenses to the eye. UV radiation incident from an angle of 135°-150° behind a lens wearer is reflected from the back side of lenses. The usual antireflective coatings considerably increase reflection of UV radiation. To provide reliable labeling of the protective potential of lenses, an eye-sun protection factor (E-SPF®) has been developed. It integrates UV transmission as well as UV reflectance of lenses. The E-SPF® compares well with established skin-sun protection factors and provides clear messages to eye health care providers and to lay consumers.

ASSESSMENT OF THE RISK OF SOLAR ULTRAVIOLET RADIATION TO AMPHIBIANS. II: IN SITU CHARACTERIZATION OF SOLAR ULTRAVIOLET RADIATION IN AMPHIBIAN HABITATS

EPA Science Inventory

Ultraviolet B (UVB) radiation has been hypothesized as a potential cause of amphibian population declines and increased incidences of malformations. Realistic studies documenting UV irradiance or dose have rarely been conducted in wetlands used by amphibians. We demonstrate that ...

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.

Effects of sunlight exposure on grapevine powdery mildew development.

PubMed

Austin, Craig N; Wilcox, Wayne F

2012-09-01

Natural and artificially induced shade increased grapevine powdery mildew (Erysiphe necator) severity in the vineyard, with foliar disease severity 49 to 75% higher relative to leaves in full sun, depending on the level of natural shading experienced and the individual experiment. Cluster disease severities increased by 20 to 40% relative to those on check vines when ultraviolet (UV) radiation was filtered from sunlight reaching vines in artificial shading experiments. Surface temperatures of leaves in full sunlight averaged 5 to 8°C higher than those in natural shade, and in one experiment, filtering 80% of all wavelengths of solar radiation, including longer wavelengths responsible for heating irradiated tissues, increased disease more than filtering UV alone. In controlled environment experiments, UV-B radiation reduced germination of E. necator conidia and inhibited both colony establishment (hyphal formation and elongation) and maturity (latent period). Inhibitory effects of UV-B radiation were significantly greater at 30°C than at 20 or 25°C. Thus, sunlight appears to inhibit powdery mildew development through at least two mechanisms, i.e., (i) UV radiation's damaging effects on exposed conidia and thalli of the pathogen; and (ii) elevating temperatures of irradiated tissues to a level supraoptimal or inhibitory for pathogen development. Furthermore, these effects are synergistic at temperatures near the upper threshold for disease development.

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.

Research on the calibration of ultraviolet energy meters

NASA Astrophysics Data System (ADS)

Lin, Fangsheng; Yin, Dejin; Li, Tiecheng; Lai, Lei; Xia, Ming

2016-10-01

Ultraviolet (UV) radiation is a kind of non-lighting radiation with the wavelength range from 100nm to 400nm. Ultraviolet irradiance meters are now widely used in many areas. However, as the development of science and technology, especially in the field of light-curing industry, there are more and more UV energy meters or UV-integrators need to be measured. Because the structure, wavelength band and measured power intensity of UV energy meters are different from traditional UV irradiance meters, it is important for us to take research on the calibration. With reference to JJG879-2002, we SIMT have independently developed the UV energy calibration device and the standard of operation and experimental methods for UV energy calibration in detail. In the calibration process of UV energy meter, many influencing factors will affect the final results, including different UVA-band UV light sources, different spectral response for different brands of UV energy meters, instability and no uniformity of UV light source and temperature. Therefore we need to take all of these factors into consideration to improve accuracy in UV energy calibration.

Influence of tropospheric ozone control on exposure to ultraviolet radiation at the surface.

PubMed

Madronich, Sasha; Wagner, Mark; Groth, Philip

2011-08-15

Improving air quality by reducing ambient ozone (O(3)) will likely lower O(3) concentrations throughout the troposphere and increase the transmission of solar ultraviolet (UV) radiation to the surface. The changes in surface UV radiation between two control scenarios (nominally 84 and 70 ppb O(3) for summer 2020) in the Eastern two-thirds of the contiguous U.S. are estimated, using tropospheric O(3) profiles calculated with a chemistry-transport model (Community Multi-Scale Air Quality, CMAQ) as inputs to a detailed model of the transfer of solar radiation through the atmosphere (tropospheric ultraviolet-visible, TUV) for clear skies, weighed for the wavelengths known to induce sunburn and skin cancer. Because the incremental emission controls differ according to region, strong spatial variability in O(3) reductions and in corresponding UV radiation increments is seen. The geographically averaged UV increase is 0.11 ± 0.03%, whereas the population-weighted increase is larger, 0.19 ± 0.06%, because O(3) reductions are greater in more densely populated regions. These relative increments in exposure are non-negligible given the already high incidence of UV-related health effects, but are lower by an order of magnitude or more than previous estimates.

Effect of heat-setting on UV protection and antibacterial properties of cotton/spandex fabric

NASA Astrophysics Data System (ADS)

Pervez, M. N.; Talukder, M. E.; Shafiq, F.; Hasan, K. M. F.; Taher, M. A.; Meraz, M. M.; Cai, Y.; Lin, Lina

2018-01-01

An unexampled approach for simultaneous heat setting process with optimized condition at C3 (140°C, 45 s) and functional finishing, i.e. UV protection and antibacterial properties of cotton/spandex fabric were studied in this research. Experimental results disclosed that, ameliorative antibacterial efficacy and perdurable UV protection of heat-treated cotton/spandex fabrics with best sample A3 among all samples was achieved and mechanical properties also improved as the temperature rose from 120 to 140°C. In addition, Ultraviolet (UV) radiation protection and antibacterial properties are becoming increasingly necessary for human health, and textiles play an important role and this report will be appurtenant to meet regular demand.

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.

Decontamination Efficacy of Ultraviolet Radiation against Biofilms of Common Nosocomial Bacteria.

PubMed

Tingpej, Pholawat; Tiengtip, Rattana; Kondo, Sumalee

2015-06-01

Ultraviolet radiation (UV) is commonly used to destroy microorganisms in the health-care environment. However, the efficacy of UV radiation against bacteria growing within biofilms has never been studied. To measure the sterilization effectiveness of UV radiation against common healthcare associated pathogens growing within biofilms. Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Streptococcus epidermidis, Escherichia coli, ESBL-producing E. coli, Pseudomonas aeruginosa and Acinetobacter baumannii were cultivated in the Calgary Biofilm Device. Their biofilms were placed 50 cm from the UV lamp within the Biosafety Cabinet. Viability test, crystal violet assay and a scanning electron microscope were used to evaluate the germicidal efficacy. Within 5 minutes, UV radiation could kill S. aureus, MRSA, S. epidermidis, A. baumannii and ESBL-producing E. coli completely while it required 20 minutes and 30 minutes respectively to kill E. coli and P. aeruginosa. However, the amounts of biomass and the ultrastructure between UV-exposed biofilms and controls were not significantly different. UV radiation is effective in inactivating nosocomial pathogens grown within biofilms, but not removing biofilms and EPS. The biofilm of P. aeruginosa was the most durable.

Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light.

PubMed

Sommers, Christopher H; Scullen, O J; Sheen, Shiowshuh

2016-01-01

Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0-25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm(2). UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers.

Ultraviolet-B radiation in a row-crop canopy: an extended 1-D model

Treesearch

Wei Gao; Richard H. Grant; Gordon M. Heisler; James R. Slusser

2003-01-01

A decrease in stratospheric ozone may result in a serious threat to plants, since biologically active short-wavelength ultraviolet-B (UV-B 280-320 nm) radiation will increase even with a relatively small decrease in ozone. Numerous investigations have demonstrated that the effect of UV-B enhancements on plants includes reduction in grain yield, alteration in species...

A geometric ultraviolet-B radiation transfer model applied to vegetation canopies

Treesearch

Wei Gao; Richard H. Grant; Gordon M. Heisler; James R. Slusser

2002-01-01

The decrease in stratospheric ozone (O3) has prompted continued efforts to assess the potential damage to plant and animal life due to enhanced levels of solar ultraviolet (UV)-B (280-320 nm) radiation. The objective of this study was to develop and evaluate an analytical model to simulate the UV-B irradiance loading on horizontal below- canopy...

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.

Assessment of occupational exposure to heat stress and solar ultraviolet radiation among groundskeepers in an eastern North Carolina university setting.

PubMed

Beck, Nicole; Balanay, Jo Anne G; Johnson, Terri

2018-02-01

Groundskeepers spend most of the year working outdoors, exposing them to heat and solar ultraviolet (UV) radiation and increasing their risk to related adverse health effects. Various studies on heat and UV exposures in different occupations have been published, but those on groundskeepers are rare. The purpose of this study was to assess the exposure to heat stress and solar UV radiation among groundskeepers in an eastern North Carolina university setting. Wet bulb globe temperature (WBGT) index using a heat stress monitor and UV effective irradiance (UV eff ) index using a digital UV meter were recorded in various work areas three times a day (morning, noon, afternoon) and during three seasons (spring, summer, fall). Data analysis was conducted using descriptive statistics, analysis of variance (ANOVA), Tukey Honestly Significant Difference (HSD), and Pearson Correlation tests. The mean (±SD) WBGT index was the highest in the afternoon (25.4 ± 5.0°C), summer (27.8 ± 3.1°C), and July (29.0 ± 2.6°C); the mean UV eff index was the highest at noon, summer and June (0.0116 ± 0.0061, 0.0101 ± 0.0081, and 0.0114 ± 0.0089 mW/cm 2 , respectively). Differences in the mean WBGT and UV eff indices within the time periods of day, seasons and months were significant (P < 0.01). The overall correlation between WBGT and UV indices was moderate (r = 0.42, P < 0.01) but lack of correlation was found during different times of the day during the fall and summer seasons. The largest percentages of WBGT indices exceeding the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs) for different workloads were found in the afternoon (11.3-40.7%), summer (14.6-56%), and July (28.8-76.3%). The mean UV eff for noon (0.0116 mW/cm 2 ) and afternoon (0.0100 mW/cm 2 ) exceeded the TLV for 30-min exposure. This study shows that groundskeepers are potentially exposed to excessive heat stress and UV radiation, and are at risk to developing heat- and UV-related illnesses. The study findings will be beneficial in implementing recommended control measures to prevent heat stress and UV exposure among groundskeepers and other similar outdoor workers.

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.

Influence of ambient ultraviolet radiation on Bufo calamita egg development in a semiarid zone (Catalonia, Spain).

PubMed

Oromi, Neus; Marquis, Olivier; Miaud, Claude; Sanuy, Delfi

2008-01-01

Several experiments have shown that ambient ultraviolet-B radiation (UV-B) has negative effects on the development of amphibians' embryos. We studied the effects of UV-B radiation on development, survival and frequency of deformity during egg development in the Natterjack toad (Bufo calamita) from a semiarid region of Lleida (Catalonia, Spain). Eggs exposed to ambient levels of UV-B and those protected from UV-B with a filter exhibited similar developmental rate, mortality rate and frequency of developmental anomalies. These experiments show that eggs of Bufo calamita of the studied population are able to develop normally during embryonic period when exposed to current high levels of UV-B observed in Catalonia. These results will be used as reference for future studies on geographic variation in UV-B tolerance in this species.

Ultraviolet-induced responses in two species of climax tropical marine macrophytes.

PubMed

Detrés, Y; Armstrong, R A; Connelly, X M

2001-09-01

In tropical regions nominal reductions in stratospheric ozone could be detrimental to marine organisms that live near their upper tolerance levels of ultraviolet (UV) radiation and temperature. Well-known plant responses to UV include inhibition of photosynthesis, reductions in chlorophyll content, morphological changes and production of UV absorbing compounds such as flavonoids. An assessment of the effects and responses of two tropical marine macrophytes to full solar radiation and solar radiation depleted of UV were conducted in southwestern Puerto Rico. Changes in concentration of photosynthetic and photoprotective pigments, and in leaf optical properties of the red mangrove Rhizophora mangle and the seagrass Thalassia testudinum, were evaluated in field exclusion experiments. Rhizophora mangle exposed to full solar radiation showed lower leaf reflectance and a shift of 5 nm in the inflection point of the red edge. Thalassia testudinum samples excluded from UV had significant increases in total chlorophyll and carotenoid concentrations. These marine macrophytes showed increments in their concentration of UV-B absorbing compounds with exposure to UV radiation. Results indicate that even minor increases in UV radiation at low latitudes could have significant effects on the pigment composition of these climax species.

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

NASA Astrophysics Data System (ADS)

Peng, Dequn; Qin, Wei; Wu, Xiaohong

2015-06-01

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

Inhibition of the Induced Formation of Tryptophanase in Escherichia coli by Near-Ultraviolet Radiation

PubMed Central

Swenson, P. A.; Setlow, R. B.

1970-01-01

Induced formation of tryptophanase in Escherichia coli B/r is temporarily inhibited by near-ultraviolet (UV) irradiation. The inhibition is greater when irradiation is at 5 C than when at room temperature. Hence, the inhibition is the result of a photochemical, rather than photoenzymatic, alteration of some cellular component. The action spectrum has a peak in the region of 334 nm and is similar to that for growth delay. However, inhibition of tryptophanase formation is more sensitive to near-UV irradiation than are growth, respiration, and the induced formation of β-galactosidase. Thus, for tryptophanase the lack of formation cannot be due to general inhibition of metabolism. Pyridoxal phosphate absorbs in the near-UV region of the spectrum and is a cofactor for tryptophanase, but this enzyme in induced cells is not inactivated by near UV-radiations. An experiment in which toluene-treated suspensions from irradiated and unirradiated cells were mixed showed that irradiation does not cause the formation of an inhibitor of tryptophanase activity. The possibility remains that the absorption of radiant energy by pyridoxal phosphate interferes with the synthesis of tryptophanase. PMID:4914082

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.

Ultraviolet Radiation Round-Robin Testing of Various Backsheets for Photovoltaic Modules

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

Koehl, Michael; Ballion, Amal; Lee, Yu-Hsien

2015-06-14

Durability testing of materials exposed to natural weathering requires testing of the ultraviolet (UV) stability, especially for polymeric materials. The type approval testing of photovoltaic (PV) modules according to standards IEC 61215 and IEC 61646, which includes a so-called UV preconditioning test with a total UV dose of 15 kWh/m2, does not correspond to the real loads during lifetime. Between 3%-10% of the UV radiation has to be in the spectral range between 280 and 320 nm (UV-B) in the recent editions of the standards. However, the spectral distribution of the radiation source is very important because different samples showmore » very individual spectral sensitivity for the radiation offered. Less than 6% of the intensity of solar radiation exists in the UV range. In the case of an increase of the intensity of the light source for accelerating the UV test, overheating of the samples would have to be prevented more rigorously and the temperature of the samples have to be measured to avoid misinterpretation of the test results.« less

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 the developed classification for Moscow. Booth, C.R. and S. Madronich, 1994: Radiation amplification factors: improved formulation accounts for large increases in ultraviolet radiation associated with Antarctic ozone depletion. In: Ultraviolet Radiation in Antarctica: Measurements and Biological Research [Weiler, C.S. and P.A. Penhale (eds.)]. AGU Antarctic Research Series, 62, Washington, DC, USA, 39-42. Chubarova N.Y., 2008: UV variability in Moscow according to long-term UV measurements and reconstruction model. Atmos.Chem.Phys., 8, 3025-3031 Oriowo, M. et al., 2001:, Action spectrum for in vitro UV-induced cataract using whole lenses. Invest.Ophthalmol.&Vis.Sci, 42, 2596-2602. CIE, 1993: Reference Action Spectra for Ultraviolet Induced Erythema and Pigmentation of Different Human skin Types. CIE Research Note, CIE Technical Collection., N.3 CIE, 2006: Action spectrum for the production of previtamin D3 in human skin, Technical report 174, International commission on illumination

Repair of Ultraviolet Radiation Damage in Sensitive Mutants of Micrococcus radiodurans

PubMed Central

Moseley, B. E. B.

1969-01-01

Various aspects of the repair of ultraviolet (UV) radiation-induced damage were compared in wild-type Micrococcus radiodurans and two UV-sensitive mutants. Unlike the wild type, the mutants are more sensitive to radiation at 265 nm than at 280 nm. The delay in deoxyribonucleic acid (DNA) synthesis following exposure to UV is about seven times as long in the mutants as in the wild type. All three strains excise UV-induced pyrimidine dimers from their DNA, although the rate at which cytosine-thymine dimers are excised is slower in the mutants. The three strains also mend the single-strand breaks that appear in the irradiated DNA as a result of dimer excision, although the process is less efficient in the mutants. It is suggested that the increased sensitivity of the mutants to UV radiation may be caused by a partial defect in the second step of dimer excision. PMID:5773016

Sulfur, ultraviolet radiation, and the early evolution of life

NASA Technical Reports Server (NTRS)

Kasting, J. F.; Zahnle, K. J.; Pinto, J. P.; Young, A. T.

1989-01-01

The present biosphere is shielded from harmful solar near ultraviolet (UV) radiation by atmospheric ozone. It is suggested that elemental sulfur vapor could have played a similar role in an anoxic, ozone-free, primitive atmosphere. Sulfur vapor would have been produced photochemically from volcanogenic SO2 and H2S. It is composed of ring molecules, primarily S8, that absorb strongly throughout the near UV, yet are expected to be relatively stable against photolysis and chemical attack. It is also insoluble in water and would thus have been immune to rainout or surface deposition over the oceans. Since the concentration of S8 in the primitive atmosphere would have been limited by its saturation vapor pressure, surface temperatures of 45 C or higher, corresponding to carbon dioxide partial pressures exceeding 2 bars, are required to sustain an effective UV screen. A warm, sulfur-rich, primitive atmosphere is consistent with inferences drawn from molecular phylogeny, which suggest that some of the earliest organisms were thermophilic bacteria that metabolized elemental sulfur.

Ultraviolet safety assessments of insect light traps.

PubMed

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

2016-01-01

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

Occupational skin cancer induced by ultraviolet radiation and its prevention.

PubMed

Diepgen, T L; Fartasch, M; Drexler, H; Schmitt, J

2012-08-01

Skin cancer is by far the most common kind of cancer diagnosed in many western countries and ultraviolet radiation is the most important risk factor for cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). Although employees at several workplaces are exposed to increased levels of UV radiation, skin cancer due to long-term intense occupational exposure to UV radiation is often not considered as occupational disease. The actually available evidence in the epidemiological literature clearly indicates that occupational UV radiation exposure is a substantial and robust risk factor for the development of cutaneous SCC and also clearly shows a significant risk for developing BCC. There is enough scientific evidence that outdoor workers have an increased risk of developing work-related occupational skin cancer due to natural UV radiation exposure and adequate prevention strategies must be implemented. The three measures which are successful and of particular importance in the prevention of nonmelanoma skin cancer in outdoor workers are changes in behaviour regarding awareness of health and disease resulting from exposure to natural UV radiation, protection from direct UV radiation by wearing suitable clothing, and regular and correct use of appropriate sunscreens. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

On the history of phyto-photo UV science (not to be left in skoto toto and silence).

PubMed

Björn, Lars Olof

2015-08-01

This review of the history of ultraviolet photobiology focuses on the effects of UV-B (280-315 nm) radiation on terrestrial plants. It describes the early history of ultraviolet photobiology, the discovery of DNA as a major ultraviolet target and the discovery of photoreactivation and photolyases, and the later identification of Photosystem II as another important target for damage to plants by UV-B radiation. Some experimental techniques are briefly outlined. The insight that the ozone layer was thinning spurred the interest in physiological and ecological effects of UV-B radiation and resulted in an exponential increase over time in the number of publications and citations until 1998, at which time it was realized by the research community that the Montreal Protocol regulating the pollution of the atmosphere with ozone depleting substances was effective. From then on, the publication and citation rate has continued to rise exponentially, but with an abrupt change to lower exponents. We have now entered a phase when more emphasis is put on the "positive" effects of UV-B radiation, and with more emphasis on regulation than on damage and inhibition. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

UV - GAITHERSBURG MD

EPA Science Inventory

Brewer 105 is located in Gaithersburg MD, measuring ultraviolet solar radiation. Irradiance and column ozone are derived from this data. Ultraviolet solar radiation is measured with a Brewer Mark IV, single-monochrometer, spectrophotometer manufactured by SCI-TEC Instruments, Inc...

Solar Ultraviolet-B Radiation Affects Seedling Emergence, DNA Integrity, Plant Morphology, Growth Rate, and Attractiveness to Herbivore Insects in Datura ferox.

PubMed Central

Ballare, C. L.; Scopel, A. L.; Stapleton, A. E.; Yanovsky, M. J.

1996-01-01

To study functional relationships between the effects of solar ultraviolet-B radiation (UV-B) on different aspects of the physiology of a wild plant, we carried out exclusion experiments in the field with the summer annual Datura ferox L. Solar UV-B incident over Buenos Aires reduced daytime seedling emergence, inhibited stem elongation and leaf expansion, and tended to reduce biomass accumulation during early growth. However, UV-B had no effect on calculated net assimilation rate. Using a monoclonal antibody specific to the cyclobutane-pyrimidine dimer (CPD), we found that plants receiving full sunlight had more CPDs per unit of DNA than plants shielded from solar UV-B, but the positive correlation between UV-B and CPD burden tended to level off at high (near solar) UV-B levels. At our field site, Datura plants were consumed by leaf beetles (Coleoptera), and the proportion of plants attacked by insects declined with the amount of UV-B received during growth. Field experiments showed that plant exposure to solar UV-B reduced the likelihood of leaf beetle attack by one-half. Our results highlight the complexities associated with scaling plant responses to solar UV-B, because they show: (a) a lack of correspondence between UV-B effects on net assimilation rate and whole-plant growth rate, (b) nonlinear UV-B dose-response curves, and (c) UV-B effects of plant attractiveness to natural herbivores. PMID:12226382

The role of ultraviolet radiation in the pathogenesis of pterygia (Review).

PubMed

Zhou, Wei-Ping; Zhu, Yuan-Fang; Zhang, Bei; Qiu, Wen-Ya; Yao, Yu-Feng

2016-07-01

Pterygium is a common ophthalmic disease affecting humans only. Extensive epidemiological data have demonstrated a causative effect of chronic ultraviolet (UV) radiation on pterygia. Progress has been made in determining the origin of pterygia, their nasal predilection and wing‑shaped appearance, and the roles of UV radiation in the initiation and the development of pterygia. In the present review, the current understanding of the involvement of UV radiation in the pathogenesis of pterygia is summarized. This involvement includes the alteration of limbal stem cells and fibroblasts that contribute to the initiation of pterygia and the induction of various pro‑inflammatory cytokines, growth factors and matrix metalloproteinases that promote the progression of pterygia. Further elucidation of the roles of UV radiation in the pathogenesis of pterygia may help to encourage individuals at risk of developing pterygia to take preventive measures and aid researchers in the development of novel targeted therapeutic agents to treat pterygia.

UV-C induces K sup + efflux from bean but not from oat leaves

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

Huerta, A.J.; Gueltig, B.G.

Previous reports have shown that ultraviolet radiation (UV) induces a specific leakage of K{sup +} from cells in culture as well as from guard cells of bean leaves resulting in stomatal closure. In an effort to determine how general this response may be in photosynthetic leaf cells, we measured the UV-C-induced K{sup +} efflux from irradiated 10-14 day-old bean and oat leaf sections. Our results show that oat leaves do not respond to UV-C irradiation with K{sup +} efflux. However UV-C irradiated bean leaves leaked K{sup +} at a rate of approximately 47 nmoles cm{sup {minus}2} h{sup {minus}1} and themore » leakage was linear for at least 3.5 hours. The source cells for K{sup +} efflux and the possible mechanisms responsible for this difference in UV-sensitivity will be discussed.« less

Early exposure to ultraviolet-B radiation decreases immune function later in life

PubMed Central

Ceccato, Emma; Cramp, Rebecca L.; Seebacher, Frank; Franklin, Craig E.

2016-01-01

Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction of the ozone layer. Amphibian tadpoles are particularly sensitive to the damaging effects of UV-B radiation, with exposure disrupting growth and fitness in many species. Given that UV-B can disrupt immune function in other animals, we tested the hypothesis that early UV-B exposure suppresses the immune responses of amphibian tadpoles and subsequent juvenile frogs. We exposed Limnodynastes peronii tadpoles to sublethal levels of UV-B radiation for 6 weeks after hatching, then examined indices of immune function in both the tadpoles and the subsequent metamorphs. There was no significant effect of UV-B on tadpole leucocyte counts or on their response to an acute antigen (phytohaemagglutinin) challenge. However, early UV-B exposure resulted in a significant reduction in both metamorph leucocyte abundance and their response to an acute phytohaemagglutinin challenge. These data demonstrate that early UV-B exposure can have carry-over effects on later life-history traits even if the applied stressor has no immediately discernible effect. These findings have important implications for our understanding of the effects of UV-B exposure on amphibian health and susceptibility to diseases such as chytridiomycosis. PMID:27668081

Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

NASA Astrophysics Data System (ADS)

Jablonowski, H.; Bussiahn, R.; Hammer, M. U.; Weltmann, K.-D.; von Woedtke, Th.; Reuter, S.

2015-12-01

Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100-400 nm) and, in particular, vacuum ultraviolet (VUV, 10-200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH2O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H2O2) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O2•-) and hydroxyl radicals (•OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

Protective effect of cerium ion against ultraviolet B radiation-induced water stress in soybean seedlings.

PubMed

Mao, Chun Xia; Chen, Min Min; Wang, Lei; Zou, Hua; Liang, Chan Juan; Wang, Li Hong; Zhou, Qing

2012-06-01

Effects of cerium ion (Ce(III)) on water relations of soybean seedlings (Glycine max L.) under ultraviolet B radiation (UV-B, 280-320 nm) stress were investigated under laboratory conditions. UV-B radiation not only affected the contents of two osmolytes (proline, soluble sugar) in soybean seedlings, but also inhibited the transpiration in soybean seedlings by decreasing the stomatal density and conductance. The two effects caused the inhibition in the osmotic and metabolic absorption of water, which decreased the water content and the free water/bound water ratio. Obviously, UV-B radiation led to water stress, causing the decrease in the photosynthesis in soybean seedlings. The pretreatment with 20 mg L(-1) Ce(III) could alleviate UV-B-induced water stress by regulating the osmotic and metabolic absorption of water in soybean seedlings. The alleviated effect caused the increase in the photosynthesis and the growth of soybean seedlings. It is one of the protective effect mechanisms of Ce(III) against the UV-B radiation-induced damage to plants.

UNLAMINATED GAFCHROMIC EBT3 FILM FOR ULTRAVIOLET RADIATION MONITORING.

PubMed

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

2017-11-01

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

Analysis of the UV-B Regime and Potential Effects on Alfalfa

NASA Technical Reports Server (NTRS)

Seitz, Jeffery C.

1998-01-01

Life at the surface of the Earth, over the last 400 m.y., evolved under conditions of decreased short-wave radiation (i.e., ultraviolet) relative to solar output due to absorption and scattering by constituents (e.g., ozone, water vapor, aerosols) in the upper atmosphere. However, a significant amount of ultraviolet radiation in the range from 280-320 nm, known as ultraviolet-B radiation, reaches the Earth's surface and has sufficient energy to be damaging to biologic tissue. Natural fluctuations in atmospheric constituents (seasonal variation, volcanic eruptions, etc.), changes in the orbital attitude of the Earth (precession, axial tilt, orbital eccentricity), and long-term solar variability contribute to changes in the total amount of ultraviolet radiation reaching the surface of the Earth, and thus, the biosphere. More recently, the atmospheric release of commercial propellants and refrigerants, known as chlorofluorocarbons (CFCs), has contributed to a significant depletion in naturally occurring ozone in the stratosphere. Thus, decreased stratospheric ozone has resulted in an increased UV-B flux at the Earth's surface which may have profound effects on terrestrial and marine organisms. In this study, we are investigating the effects of differing solar UV-B fluxes on alfalfa (Medicago sativa L.), an important agricultural crop. A long-term goal of this research is to develop spectral signatures to detect plant response to increased UV-B radiation from remote sensor platforms.

Importance of biologically active aurora-like ultraviolet emission: stochastic irradiation of Earth and Mars by flares and explosions.

PubMed

Smith, David S; Scalo, John; Wheeler, J Craig

2004-10-01

Habitable planets will be subject to intense sources of ionizing radiation and fast particles from a variety of sources--from the host star to distant explosions--on a variety of timescales. Monte Carlo calculations of high-energy irradiation suggest that the surfaces of terrestrial-like planets with thick atmospheres (column densities greater than about 100 g cm(-2)) are well protected from directly incident X-rays and gamma-rays, but we find that sizeable fractions of incident ionizing radiation from astrophysical sources can be redistributed to biologically and chemically important ultraviolet wavelengths, a significant fraction of which can reach the surface. This redistribution is mediated by secondary electrons, resulting from Compton scattering and X-ray photoabsorption, the energies of which are low enough to excite and ionize atmospheric molecules and atoms, resulting in a rich aurora-like spectrum. We calculate the fraction of energy redistributed into biologically and chemically important wavelength regions for spectra characteristic of stellar flares and supernovae using a Monte-Carlo transport code and then estimate the fraction of this energy that is transmitted from the atmospheric altitudes of redistribution to the surface for a few illustrative cases. For atmospheric models corresponding to the Archean Earth, we assume no significant ultraviolet absorbers, only Rayleigh scattering, and find that the fraction of incident ionizing radiation that is received at the surface in the form of redistributed ultraviolet in the biologically relevant 200-320 nm region (UV-C and UV-B bands) can be up to 4%. On the present-day Earth with its ultraviolet ozone shield, this fraction is found to be 0.2%. Both values are many orders of magnitude higher than the fraction of direct ionizing radiation reaching the surface. This result implies that planetary organisms will be subject to mutationally significant, if intermittent, fluences of UV-B and harder radiation even in the presence of a narrow-band ultraviolet shield like ozone. We also calculate the surficial transmitted fraction of ionizing radiation and redistributed ultraviolet radiation for two illustrative evolving Mars atmospheres whose initial surface pressures were 1 bar. We discuss the frequency with which redistributed ultraviolet flux from parent star flares exceeds the parent star ultraviolet flux at the planetary surface. We find that the redistributed ultraviolet from parent star flares is probably a fairly rare intermittent event for habitable zone planets orbiting solar-type stars except when they are young, but should completely dominate the direct steady ultraviolet radiation from the parent star for planets orbiting all stars less massive than about 0.5 solar masses. Our results suggest that coding organisms on such planets (and on the early Earth) may evolve very differently than on contemporary Earth, with diversity and evolutionary rate controlled by a stochastically varying mutation rate and frequent hypermutation episodes.

Ultraviolet damage to the eye revisited: eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear

PubMed Central

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

2014-01-01

Ultraviolet (UV) radiation potentially damages the skin, the immune system, and structures of the eye. A useful UV sun protection for the skin has been established. Since a remarkable body of evidence shows an association between UV radiation and damage to structures of the eye, eye protection is important, but a reliable and practical tool to assess and compare the UV-protective properties of lenses has been lacking. Among the general lay public, misconceptions on eye-sun protection have been identified. For example, sun protection is mainly ascribed to sunglasses, but less so to clear lenses. Skin malignancies in the periorbital region are frequent, but usual topical skin protection does not include the lids. Recent research utilized exact dosimetry and demonstrated relevant differences in UV burden to the eye and skin at a given ambient irradiation. Chronic UV effects on the cornea and lens are cumulative, so effective UV protection of the eyes is important for all age groups and should be used systematically. Protection of children’s eyes is especially important, because UV transmittance is higher at a very young age, allowing higher levels of UV radiation to reach the crystalline lens and even the retina. Sunglasses as well as clear lenses (plano and prescription) effectively reduce transmittance of UV radiation. However, an important share of the UV burden to the eye is explained by back reflection of radiation from lenses to the eye. UV radiation incident from an angle of 135°–150° behind a lens wearer is reflected from the back side of lenses. The usual antireflective coatings considerably increase reflection of UV radiation. To provide reliable labeling of the protective potential of lenses, an eye-sun protection factor (E-SPF®) has been developed. It integrates UV transmission as well as UV reflectance of lenses. The E-SPF® compares well with established skin-sun protection factors and provides clear messages to eye health care providers and to lay consumers. PMID:24379652

[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.

Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants.

PubMed

Zhang, Chan; Yang, Yong-Ping; Duan, Yuan-Wen

2014-03-31

Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Floral forms were categorized as either protecting or exposing pollen grains to UV-B. The floral materials of plants with exposed and protected pollen grains were able to block UV-B at similar levels. Exposure to UV-B radiation in vitro resulted in a significantly greater loss of viability in pollen from plant species with protective floral structures. The pronounced sensitivity of protected pollen to UV-B radiation was associated with the type of flower structure. These findings demonstrate that UV-B plays an important role in the evolution of protective floral forms in alpine plants.

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

Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light

PubMed Central

Sommers, Christopher H.; Scullen, O. J.; Sheen, Shiowshuh

2016-01-01

Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0–25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm2. UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers. PMID:27148167

Ultraviolet radiation-induced interleukin 6 release in HeLa cells is mediated via membrane events in a DNA damage-independent way.

PubMed

Kulms, D; Pöppelmann, B; Schwarz, T

2000-05-19

Evidence exists that ultraviolet radiation (UV) affects molecular targets in the nucleus or at the cell membrane. UV-induced apoptosis was found to be mediated via DNA damage and activation of death receptors, suggesting that nuclear and membrane effects are not mutually exclusive. To determine whether participation of nuclear and membrane components is also essential for other UV responses, we studied the induction of interleukin-6 (IL-6) by UV. Exposing HeLa cells to UV at 4 degrees C, which inhibits activation of surface receptors, almost completely prevented IL-6 release. Enhanced repair of UV-mediated DNA damage by addition of the DNA repair enzyme photolyase did not affect UV-induced IL-6 production, suggesting that in this case membrane events predominant over nuclear effects. UV-induced IL-6 release is mediated via NFkappaB since the NFkappaB inhibitor MG132 or transfection of cells with a super-repressor form of the NFkappaB inhibitor IkappaB reduced IL-6 release. Transfection with a dominant negative mutant of the signaling protein TRAF-2 reduced IL-6 release upon exposure to UV, indicating that UV-induced IL-6 release is mediated by activation of the tumor necrosis factor receptor-1. These data demonstrate that UV can exert biological effects mainly by affecting cell surface receptors and that this is independent of its ability to induce nuclear DNA damage.

UV - EVERGLADES NATIONAL PARK FL

EPA Science Inventory

Brewer 135 is located in Everglades NP, measuring ultraviolet solar radiation. Irradiance and column ozone are derived from this data. Ultraviolet solar radiation is measured with a Brewer Mark IV, single-monochrometer, spectrophotometer manufactured by SCI-TEC Instruments, Inc. ...

UV - THEODORE ROOSEVELT NATIONAL PARK ND

EPA Science Inventory

Brewer 131 is located in Theodore Roosevelt NP (South Section), measuring ultraviolet solar radiation. Irradiance and column ozone are derived from this data. Ultraviolet solar radiation is measured with a Brewer Mark IV, single-monochrometer, spectrophotometer manufactured by SC...

INTERNAL FILTERS: PROSPECTS FOR UV-ACCLIMATION IN HIGHER PLANTS

EPA Science Inventory

Wavelength-selective absorption of solar radiation within plant leaves allows penetration of visible radiation (400-700nm) to the chloroplasts, while removing much of the damaging ultraviolet-B (UV-B, 280-320 nm) radiation. Flavonoids are important in this wavelength-selective ab...

LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS

EPA Science Inventory

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

Cellular defense against UVB-induced phototoxicity by cytosolic NADP(+)-dependent isocitrate dehydrogenase.

PubMed

Jo, Seung-Hee; Lee, So-Hyun; Chun, Hang Suk; Lee, Su Min; Koh, Ho-Jin; Lee, Sung-Eun; Chun, Jang-Soo; Park, Jeen-Woo; Huh, Tae-Lin

2002-03-29

Ultraviolet (UV) radiation is known as a major cause of skin photoaging and photocarcinogenesis. Many harmful effects of UV radiation are associated with the generation of reactive oxygen species. Recently, we have shown that NADP(+)-dependent isocitrate dehydrogenase is involved in the supply of NADPH needed for GSH production against cellular oxidative damage. In this study we investigated the role of cytosolic form of NADP(+)-dependent isocitrate dehydrogenase (IDPc) against UV radiation-induced cytotoxicity by comparing the relative degree of cellular responses in three different NIH3T3 cells with stable transfection with the cDNA for mouse IDPc in sense and antisense orientations, where IDPc activities were 2.3-fold higher and 39% lower, respectively, than that in the parental cells carrying the vector alone. Upon exposure to UVB (312 nm), the cells with low levels of IDPc became more sensitive to cell killing. Lipid peroxidation, protein oxidation, oxidative DNA damage, and intracellular peroxide generation were higher in the cell-line expressing the lower level of IDPc. However, the cells with the highly overexpressed IDPc exhibited enhanced resistance against UV radiation, compared to the control cells. The data indicate that IDPc plays an important role in cellular defense against UV radiation-induced oxidative injury. (c)2002 Elsevier Science (USA).

Nanotherapy of cancer by photoelectrons emitted from the surface of nanoparticles exposed to nonionizing ultraviolet radiation.

PubMed

Letfullin, Renat R; George, Thomas F

2017-05-01

We introduce a new method for selectively destroying cancer cell organelles by electrons emitted from the surface of intracellularly localized nanoparticles exposed to the nonionizing ultraviolet (UV) radiation. We propose to target cancerous intracellular organelles by nanoparticles and expose them to UV radiation with energy density safe for healthy tissue. We simulate the number of photoelectrons produced by the nanoparticles made of various metals and radii, calculate their kinetic energy and compare it to the threshold energy for producing biological damage. Exposure of metal nanoparticles to UV radiation generates photoelectrons with kinetic energies up to 11 eV, which is high enough to produce single- to double-strand breaks in the DNA and damage the cancerous cell organelles.

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...

Ultraviolet safety assessments of insect light traps

PubMed Central

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

2016-01-01

ABSTRACT Near-ultraviolet (UV-A: 315–400 nm), “black-light,” electric lamps were invented in 1935 and ultraviolet insect light traps (ILTs) were introduced for use in agriculture around that time. Today ILTs are used indoors in several industries and in food-service as well as in outdoor settings. With recent interest in photobiological lamp safety, safety standards are being developed to test for potentially hazardous ultraviolet emissions. A variety of UV “Black-light” ILTs were measured at a range of distances to assess potential exposures. Realistic time-weighted human exposures are shown to be well below current guidelines for human exposure to ultraviolet radiation. These UV-A exposures would be far less than the typical UV-A exposure in the outdoor environment. Proposals are made for realistic ultraviolet safety standards for ILT products. PMID:27043058

Ultraviolet-B phototoxicity and hypothetical photomelanomagenesis: intraocular and crystalline lens photoprotection.

PubMed

Mainster, Martin A; Turner, Patricia L

2010-04-01

Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Optical radiation measurement, analysis, and perspective. Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs. Copyright 2010 Elsevier Inc. All rights reserved.

76 FR 35672 - Revised Effectiveness Determination; Sunscreen Drug Products for Over-the-Counter Human Use

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-17

... are given ultraviolet (UV) radiation doses produced by a solar simulator (i.e., a UV lamp). Under... increasingly higher UV doses produced by the solar simulator. However, because the solar simulator can produce far higher UV radiation doses than a consumer would ever receive even under the most severe sun...

CHARACTERIZATION OF RELATIVE SENSITIVITY OF AMPHIBIANS TO ULTRAVIOLET RADIATION

EPA Science Inventory

Different studies have demonstrated that solar ultraviolet (UV) radiation can adversely affect survival and development of embryonic and larval amphibians. However, because of among-laboratory variations in exposure profiles (artificial vs. natural sunlight; natural sunlight at d...

Gasdermin C is induced by ultraviolet light and contributes to MMP-1 expression via activation of ERK and JNK pathways.

PubMed

Kusumaningrum, Novi; Lee, Dong Hun; Yoon, Hyun-Sun; Kim, Yeon Kyung; Park, Chi-Hyun; Chung, Jin Ho

2018-05-01

Ultraviolet (UV) radiation plays important roles in various skin diseases including premature aging and cancer. UV has been shown to regulate the expressions of many genes including matrix metalloproteinases (MMPs). Gasdermin C (GSDMC) belongs to Gasdermin family and is known to be expressed in the epithelial cells of many tissues including the skin. However, the functions of GSDMC remain poorly understood. We aimed to investigate the role of GSDMC in UV-induced MMP-1, MMP-3, and MMP-9 expressions in human skin keratinocytes. Primary human skin keratinocytes and an immortalized human skin keratinocyte cell line (HaCaT cells) were irradiated with UV. Knockdown and overexpression of GSDMC were performed to study the effect of GSDMC. The mRNA and protein levels were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. We found that GSDMC expression is increased by UV irradiation in human skin keratinocytes. Further studies showed that GSDMC expression is increased at relatively late time points after UV irradiation and that this GSDMC induction plays important roles in the expressions of MMP-1, but not of MMP-3 and MMP-9, and the activations of ERK and JNK induced by UV. In addition, we found that overexpression of GSDMC increases the MMP-1 expression and the activities of ERK and JNK and that GSDMC-induced MMP-1 expression is suppressed by inhibition of ERK or JNK activities. Our results suggest that GSDMC is increased by UV radiation and contributes to UV-induced MMP-1 expression through the activation of ERK and JNK pathways. Copyright © 2018 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVIATION OF GIARDIA MURIS CYSTS

EPA Science Inventory

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

Experimental evaluation of optimization method for developing ultraviolet barrier coatings

NASA Astrophysics Data System (ADS)

Gonome, Hiroki; Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

2014-01-01

Ultraviolet (UV) barrier coatings can be used to protect many industrial products from UV attack. This study introduces a method of optimizing UV barrier coatings using pigment particles. The radiative properties of the pigment particles were evaluated theoretically, and the optimum particle size was decided from the absorption efficiency and the back-scattering efficiency. UV barrier coatings were prepared with zinc oxide (ZnO) and titanium dioxide (TiO2). The transmittance of the UV barrier coating was calculated theoretically. The radiative transfer in the UV barrier coating was modeled using the radiation element method by ray emission model (REM2). In order to validate the calculated results, the transmittances of these coatings were measured by a spectrophotometer. A UV barrier coating with a low UV transmittance and high VIS transmittance could be achieved. The calculated transmittance showed a similar spectral tendency with the measured one. The use of appropriate particles with optimum size, coating thickness and volume fraction will result in effective UV barrier coatings. UV barrier coatings can be achieved by the application of optical engineering.

Antioxidant capacity of flavonoid in soybean seedlings under the joint actions of rare earth element La(III) and ultraviolet-B stress.

PubMed

Peng, Qi; Zhou, Qing

2009-01-01

The dynamic state of antioxidant capacity of flavonoid was investigated for a further demonstration of alleviating the damage of the ultraviolet (UV)-B radiation in the La-treated soybean seedlings under UV-B stress. Using hydroponics culture, the effects of lanthanum on the contents of flavonoid and its ability of antioxidant under elevated ultraviolet-B radiation (280-320 nm) was studied. The results showed flavonoid content in soybean seedlings with UV-B treatment during the stress and convalescent period was increased initially and then decreased, compared with control. Membrane permeability and MDA contents increase at first (first to fifth day) and then decrease (6th-11th day). A similar change of flavonoid content and clearance of flavonoid scavenging O2- and *OH in soybean seedlings occurred. Flavonoid content and ability of flavonoid scavenging O2- and *OH in soybean seedlings with La(III) + UV-B treatment were higher than those of UV-B treatment. Meanwhile, membrane permeability and MDA contents in soybean seedlings were lower than those of UV-B treatment. Compared with control, phenylalanine content in soybean seedlings with UV-B treatment is depressed, phenylalanine content in soybean seedlings with La(III) treatment was enhanced. However, phenylalanine content in La(III) + UV-B treatment is not decreased but slightly increased, compared with UV-B treatment. It suggested that the regulative effect of La(III) of the optimum concentration on flavonoid improved the metabolism of ROS, diminished the concentration of MDA and maintained normal plasma membrane permeability, and that its protective effect against low UV-B radiation is superior to that of high UV-B radiation. The defensive effect of La(III) on soybean seedlings under UV-B stress is carried out on the layer of defense system.

Preharvest Ultraviolet C Irradiation Increased the Level of Polyphenol Accumulation and Flavonoid Pathway Gene Expression in Strawberry Fruit.

PubMed

Xu, Yanqun; Charles, Marie Thérèse; Luo, Zisheng; Mimee, Benjamin; Veronneau, Pierre-Yves; Rolland, Daniel; Roussel, Dominique

2017-11-22

Preharvest ultraviolet C (UV-C) irradiation is an innovative approach for increasing the bioactive phytochemical content of strawberries to increase the disease resistance and nutritional value. This study investigated the changes in individual flavonoids in strawberry developed with three different cumulative doses of preharvest UV-C treatment (low, 9.6 kJ m -2 ; middle, 15 kJ m -2 ; and high , 29.4 kJ m -2 ). Significant accumulation (p < 0.05) of phenolics (25-75% increase), namely, cyanidin 3-glucoside, pelargonidin 3-glucoside/rutinoside, glucoside and glucuronide of quercetin and kaempferol, and ellagic acid, was found in the fruit subjected to low and middle supplemental doses of UV-C radiation. The expression of the flavonoid pathway structural genes, i.e., FaCHS1, FaCHI, FaFHT, FaDFR, FaFLS, and FaFGT, was upregulated in the low- and middle-dose groups, while the early stage genes were not affected by the high dose. FaMYB1 was also relatively enhanced in the low- and middle-dose groups, while FaASR was upregulated in only the low-dose group. Hormetic preharvest UV-C dose ranges for enhancing the polyphenol content of strawberries were established for the first time.

Preparation and Characterization of UV Emitting Fluoride Phosphors for Phototherapy Lamps

NASA Astrophysics Data System (ADS)

Belsare, P. D.; Moharil, S. V.; Joshi, C. P.; Omanwar, S. K.

2011-10-01

The use of ultraviolet radiation for the treatment of various skin diseases is well known for long time. Phototherapy employs ultraviolet-blue radiation to cure skin diseases. The basis of phototherapy is believed to be the direct interaction of light of certain frequencies with tissue to cause a change in immune response. Currently dermatologists use UV lamps having specific emissions in UV region for treating various skin diseases. The treatment of skin diseases using artificial sources of UV radiation is now well established and more than 50 types of skin diseases are treated by phototherapy. This is an effective treatment for many skin disorders, such as psoriasis, vitiligo, ofujis disease, morphea , scleroderma, cutaneous T-cell lymphoma, lupus erythematosus, hyperbilirubinemia commonly known as infant jaundice, acne vulgaris, This paper reports photoluminescence properties of UV emitting fluoride phosphors prepared by wet chemical method. Emission characteristics of these phosphors are found similar to those of commercial UV lamp phosphors with comparable intensities. The usefulness of UV emitting fluoride phosphor is discussed in the paper.

Medical Devices; General Hospital and Personal Use Devices; Classification of the Ultraviolet Radiation Chamber Disinfection Device. Final order.

PubMed

2015-11-20

The Food and Drug Administration (FDA or the Agency) is classifying the ultraviolet (UV) radiation chamber disinfection device into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the UV radiation chamber disinfection device classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

The effect of warming and enhanced ultraviolet radiation on gender-specific emissions of volatile organic compounds from European aspen.

PubMed

Maja, Mengistu M; Kasurinen, Anne; Holopainen, Toini; Julkunen-Tiitto, Riitta; Holopainen, Jarmo K

2016-03-15

Different environmental stress factors often occur together but their combined effects on plant secondary metabolism are seldom considered. We studied the effect of enhanced ultraviolet (UV-B) (31% increase) radiation and temperature (ambient +2 °C) singly and in combination on gender-specific emissions of volatile organic compounds (VOCs) from 2-year-old clones of European aspen (Populus tremula L.). Plants grew in 36 experimental plots (6 replicates for Control, UV-A, UV-B, T, UV-A+T and UV-B+T treatments), in an experimental field. VOCs emitted from shoots were sampled from two (1 male and 1 female) randomly selected saplings (total of 72 saplings), per plot on two sampling occasions (June and July) in 2014. There was a significant UV-B×temperature interaction effect on emission rates of different VOCs. Isoprene emission rate was increased due to warming, but warming also modified VOC responses to both UV-A and UV-B radiation. Thus, UV-A increased isoprene emissions without warming, whereas UV-B increased emissions only in combination with warming. Warming-modified UV-A and UV-B responses were also seen in monoterpenes (MTs), sesquiterpenes (SQTs) and green leaf volatiles (GLVs). MTs showed also a UV × gender interaction effect as females had higher emission rates under UV-A and UV-B than males. UV × gender and T × gender interactions caused significant differences in VOC blend as there was more variation (more GLVs and trans-β-caryophyllene) in VOCs from female saplings compared to male saplings. VOCs from the rhizosphere were also collected from each plot in two exposure seasons, but no significant treatment effects were observed. Our results suggest that simultaneous warming and elevated-UV-radiation increase the emission of VOCs from aspen. Thus the contribution of combined environmental factors on VOC emissions may have a greater impact to the photochemical reactions in the atmosphere compared to the impact of individual factors acting alone. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Spectral transmittance of UV-blocking soft contact lenses: a comparative study.

PubMed

Rahmani, Saeed; Mohammadi Nia, Mohadeseh; Akbarzadeh Baghban, Alireza; Nazari, Mohammad Reza; Ghassemi-Broumand, Mohammad

2014-12-01

Three major parts of sunlight consist of visible, ultraviolet and infrared radiation. Exposure to ultraviolet radiation (UVR) can result in a spectrum of skin and ocular diseases. UV-blocking contact lenses help provide protection against harmful UV radiation. We studied the ultraviolet and visible light rays transmission in some soft UV-blocking contact lenses. Four available tinted soft lenses (Acuvue Moist, Zeiss CONTACT Day 30 Air spheric, Pretty Eyes and Sauflon 56 UV) have been evaluated for UV and visible transmission. One-way ANOVA testing was performed to establish is there a statistically significant difference between the UV regions and visible spectra means for the contact lenses (α=0.05). Pretty Eyes, Zeiss CONTACT, Acuvue Moist and Sauflon 56 UV showed UV-B transmittance value of 0.65%, 10.69%, 1.22%, and 5.78%, respectively. Pretty Eyes and Acuvue Moist had UV-A transmittance values of 32% and 34%, Sauflon 56 UV and Zeiss CONTACT had transmittance values of 48% and 43%, respectively. All of the studied lenses transmitted at least 94.6% on the visible spectrum. The results of the one-way ANOVA statistical analysis show that a statistically significant difference exists within the group of contact lenses tested for the visible (p<0.001), UV-B (p<0.001) and UV-A (p<0.001) portions of the spectrum (α=0.05). Acuvue Moist has the best UV-blocking property and also visible transmission between other tested contact lenses in this study. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

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

PubMed

Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

2018-06-15

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

Estimated ultraviolet radiation doses in wetlands in six national parks

USGS Publications Warehouse

Diamond, S.A.; Trenham, P.C.; Adams, Michael J.; Hossack, B.R.; Knapp, R.A.; Stark, L.; Bradford, D.; Corn, P.S.; Czarnowski, K.; Brooks, P.D.; Fagre, D.B.; Breen, B.; Dentenbeck, N.E.; Tonnessen, K.

2005-01-01

Ultraviolet-B radiation (UV-B, 280–320-nm wavelengths) doses were estimated for 1024 wetlands in six national parks: Acadia (Acadia), Glacier (Glacier), Great Smoky Mountains (Smoky), Olympic (Olympic), Rocky Mountain (Rocky), and Sequoia/Kings Canyon (Sequoia). Estimates were made using ground-based UV-B data (Brewer spectrophotometers), solar radiation models, GIS tools, field characterization of vegetative features, and quantification of DOC concentration and spectral absorbance. UV-B dose estimates were made for the summer solstice, at a depth of 1 cm in each wetland. The mean dose across all wetlands and parks was 19.3 W-h m−2 (range of 3.4–32.1 W-h m−2). The mean dose was lowest in Acadia (13.7 W-h m−2) and highest in Rocky (24.4 W-h m−2). Doses were significantly different among all parks. These wetland doses correspond to UV-B flux of 125.0 μW cm−2 (range 21.4–194.7 μW cm−2) based on a day length, averaged among all parks, of 15.5 h. Dissolved organic carbon (DOC), a key determinant of water-column UV-B flux, ranged from 0.6 (analytical detection limit) to 36.7 mg C L−1 over all wetlands and parks, and reduced potential maximal UV-B doses at 1-cm depth by 1%–87 %. DOC concentration, as well as its effect on dose, was lowest in Sequoia and highest in Acadia (DOC was equivalent in Acadia, Glacier, and Rocky). Landscape reduction of potential maximal UV-B doses ranged from zero to 77% and was lowest in Sequoia. These regional differences in UV-B wetland dose illustrate the importance of considering all aspects of exposure in evaluating the potential impact of UV-B on aquatic organisms.

Gage measures total radiation, including vacuum UV, from ionized high-temperature gases

NASA Technical Reports Server (NTRS)

Wood, A. D.

1969-01-01

Transient-heat transfer gage measures the total radiation intensity from vacuum ultraviolet and ionized high temperature gases. The gage includes a sensitive piezoelectric crystal that is completely isolated from any ionized flow and vacuum ultraviolet irradiation.

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…

The Space Weather and Ultraviolet Solar Variability (SWUSV) Microsatellite Mission

PubMed Central

Damé, Luc; Meftah, Mustapha; Hauchecorne, Alain; Keckhut, Philippe; Sarkissian, Alain; Marchand, Marion; Irbah, Abdenour; Quémerais, Éric; Bekki, Slimane; Foujols, Thomas; Kretzschmar, Matthieu; Cessateur, Gaël; Shapiro, Alexander; Schmutz, Werner; Kuzin, Sergey; Slemzin, Vladimir; Urnov, Alexander; Bogachev, Sergey; Merayo, José; Brauer, Peter; Tsinganos, Kanaris; Paschalis, Antonis; Mahrous, Ayman; Khaled, Safinaz; Ghitas, Ahmed; Marzouk, Besheir; Zaki, Amal; Hady, Ahmed A.; Kariyappa, Rangaiah

2013-01-01

We present the ambitions of the SWUSV (Space Weather and Ultraviolet Solar Variability) Microsatellite Mission that encompasses three major scientific objectives: (1) Space Weather including the prediction and detection of major eruptions and coronal mass ejections (Lyman-Alpha and Herzberg continuum imaging); (2) solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance from 180 to 400 nm by bands of 20 nm, plus Lyman-Alpha and the CN bandhead); (3) simultaneous radiative budget of the Earth, UV to IR, with an accuracy better than 1% in differential. The paper briefly outlines the mission and describes the five proposed instruments of the model payload: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200–220 nm Herzberg continuum) imaging (sources of variability); UPR (Ultraviolet Passband Radiometers), with 64 UV filter radiometers; a vector magnetometer; thermal plasma measurements and Langmuir probes; and a total and spectral solar irradiance and Earth radiative budget ensemble (SERB, Solar irradiance & Earth Radiative Budget). SWUSV is proposed as a small mission to CNES and to ESA for a possible flight as early as 2017–2018. PMID:25685424

The Space Weather and Ultraviolet Solar Variability (SWUSV) Microsatellite Mission.

PubMed

Damé, Luc

2013-05-01

We present the ambitions of the SWUSV (Space Weather and Ultraviolet Solar Variability) Microsatellite Mission that encompasses three major scientific objectives: (1) Space Weather including the prediction and detection of major eruptions and coronal mass ejections (Lyman-Alpha and Herzberg continuum imaging); (2) solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance from 180 to 400 nm by bands of 20 nm, plus Lyman-Alpha and the CN bandhead); (3) simultaneous radiative budget of the Earth, UV to IR, with an accuracy better than 1% in differential. The paper briefly outlines the mission and describes the five proposed instruments of the model payload: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200-220 nm Herzberg continuum) imaging (sources of variability); UPR (Ultraviolet Passband Radiometers), with 64 UV filter radiometers; a vector magnetometer; thermal plasma measurements and Langmuir probes; and a total and spectral solar irradiance and Earth radiative budget ensemble (SERB, Solar irradiance & Earth Radiative Budget). SWUSV is proposed as a small mission to CNES and to ESA for a possible flight as early as 2017-2018.

Effects of ultraviolet radiation and temperature on the ultrastructure of zoospores of the brown macroalga Laminaria hyperborea.

PubMed

Steinhoff, F S; Wiencke, C; Müller, R; Bischof, K

2008-05-01

The interactive effects of an 8 h exposure to UV radiation and altered temperatures on the ultrastructure and germination of zoospores of the sublittoral brown alga Laminaria hyperborea (Gunn.) Foslie were investigated for the first time. Spores were exposed to four temperatures (2, 7, 12 and 17 degrees C) and three light regimes (PAR, PAR + UV-A, PAR + UV-A+UV-B). Freshly-released spores of L. hyperborea lack a cell wall and contain a nucleus with fine granular nucleoplasm and a nucleolus, one chloroplast, several mitochondria, dictyosomes and an endoplasmatic reticulum. Further, several kinds of so-called adhesive vesicles, lipid globuli and physodes containing UV-absorbing phlorotannins are embedded in the cytoplasm. No eye-spot is present. Physodes were found but they were rare and small. After an 8 h exposure to UV-B, the nucleoplasm had a mottled structure, chloroplasts contained plastoglobuli, the structure of the mitochondria changed from crista- to sacculus-type and germination was strongly inhibited at all temperatures. UV-A only had an impact on the ultrastructure at the highest temperature tested. The strongest effects were found at 17 degrees C, where germination was reduced to 35%, 32% and 9% after exposure to PAR, PAR+UV-A and PAR + UV-A + UV-B, respectively. This study indicates that UV-B radiation has strong damaging effects on the physiology and ultrastructure of zoospores of L. hyperborea. The results are important for developing scenarios for the effect of enhanced UV radiation and increasing temperatures caused by global climate changes.

UV-C Adaptation of Shigella: Morphological, Outer Membrane Proteins, Secreted Proteins, and Lipopolysaccharides Effects.

PubMed

Chourabi, Kalthoum; Campoy, Susana; Rodriguez, Jesus A; Kloula, Salma; Landoulsi, Ahmed; Chatti, Abdelwaheb

2017-11-01

Water UV disinfection remains extremely important, particularly in developing countries where drinking and reclaimed crop irrigation water may spread devastating infectious diseases. Enteric bacterial pathogens, among which Shigella, are possible contaminants of drinking and bathing water and foods. To study the effect of UV light on Shigella, four strains were exposed to different doses in a laboratory-made irradiation device, given that the ultraviolet radiation degree of inactivation is directly related to the UV dose applied to water. Our results showed that the UV-C rays are effective against all the tested Shigella strains. However, UV-C doses appeared as determinant factors for Shigella eradication. On the other hand, Shigella-survived strains changed their outer membrane protein profiles, secreted proteins, and lipopolysaccharides. Also, as shown by electron microscopy transmission, morphological alterations were manifested by an internal cytoplasm disorganized and membrane envelope breaks. Taken together, the focus of interest of our study is to know the adaptive mechanism of UV-C resistance of Shigella strains.

Combined effects of Lanthanum(III) and elevated Ultraviolet-B radiation on root nitrogen nutrient in soybean seedlings.

PubMed

Huang, Guangrong; Wang, Lihong; Sun, Zhaoguo; Li, Xiaodong; Zhou, Qing; Huang, Xiaohua

2015-02-01

Rare earth element pollution and elevated ultraviolet-B (UV-B) radiation occur simultaneously in some regions, but the combined effects of these two factors on plants have not attracted enough attention. Nitrogen nutrient is vital to plant growth. In this study, the combined effects of lanthanum(III) and elevated UV-B radiation on nitrate reduction and ammonia assimilation in soybean (Glycine max L.) roots were investigated. Treatment with 0.08 mmol L(-1) La(III) did not change the effects of elevated UV-B radiation on nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), glutamate dehydrogenase (GDH), nitrate, ammonium, amino acids, or soluble protein in the roots. Treatment with 0.24 mmol L(-1) La(III) and elevated UV-B radiation synergistically decreased the NR, NiR, GS, and GOGAT activities as well as the nitrate, amino acid, and soluble protein levels, except for the GDH activity and ammonium content. Combined treatment with 1.20 mmol L(-1) La(III) and elevated UV-B radiation produced severely deleterious effects on all test indices, and these effects were stronger than those induced by La(III) or elevated UV-B radiation treatment alone. Following the withdrawal of La(III) and elevated UV-B radiation, all test indices for the combined treatments with 0.08/0.24 mmol L(-1) La(III) and elevated UV-B radiation recovered to a certain extent, but they could not recover for treatments with 1.20 mmol L(-1) La(III) and elevated UV-B radiation. In summary, combined treatment with La(III) and elevated UV-B radiation seriously affected nitrogen nutrition in soybean roots through the inhibition of nitrate reduction and ammonia assimilation.

Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

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

Jablonowski, H.; Hammer, M. U.; Reuter, S.

Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100–400 nm) and, in particular, vacuum ultraviolet (VUV, 10–200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH{sub 2}O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stablemore » reactive oxygen species, hydrogen peroxide (H{sub 2}O{sub 2}) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O{sub 2}{sup •−}) and hydroxyl radicals ({sup •}OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.« less

An immunohistochemical panel to assess ultraviolet radiation-associated oxidative skin injury.

PubMed

Mamalis, A; Fiadorchanka, N; Adams, L; Serravallo, M; Heilman, E; Siegel, D; Brody, N; Jagdeo, J

2014-05-01

Ultraviolet (UV) radiation results in a significant loss in years of healthy life, approximately 1.5 million disability-adjusted life years (DALYs), and is associated with greater than 60,000 deaths annually worldwide that are attributed to melanoma and other skin cancers. Currently, there are no standardized biomarkers or assay panels to assess oxidative stress skin injury patterns in human skin exposed to ionizing radiation. Using biopsy specimens from chronic solar UV-exposed and UV-protected skin, we demonstrate that UV radiation-induced oxidative skin injury can be evaluated by an immunohistochemical panel that stains 8-hydroxydeoxyguanosine (8-OH-dG) to assess DNA adducts, 4-hydroxy-2-nonenal (HNE) to assess lipid peroxidation, and advanced glycation end products (AGEs) to assess protein damage. We believe this panel contains the necessary cellular biomarkers to evaluate topical agents, such as sunscreens and anti-oxidants that are designed to prevent oxidative skin damage and may reduce UV-associated skin aging, carcinogenesis, and inflammatory skin diseases. We envision that this panel will become an important tool for researchers developing topical agents to protect against UV radiation and other oxidants and ultimately lead to reductions in lost years of healthy life, DALYs, and annual deaths associated with UV radiation.

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.

Abnormal ultraviolet mutagenic spectrum in plasmid DNA replicated in cultured fibroblasts from a patient with the skin cancer-prone disease, xeroderma pigmentosum

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

Seetharam, S.; Protic-Sabljic, M.; Seidman, M.M.

1987-12-01

A shuttle vector plasmid, pZ189, was utilized to assess the types of mutations that cells from a patient with xeroderma pigmentosum, complementation group D, introduce into ultraviolet (UV) damaged, replicating DNA. Patients with xeroderma pigmentosum have clinical and cellular UV hypersensitivity, increased frequency of sun-induced skin cancer, and deficient DNA repair. In comparison to UV-treated pZ189 replicated in DNA repair-proficient cells, there were fewer surviving plasmids, a higher frequency of plasmids with mutations, fewer plasmids with two or more mutations in the marker gene, and a new mutagenic hotspot. The major type of base substitution mutation was the G:C tomore » A:T transition with both cell lines. These results, together with similar findings published earlier with cells from a xeroderma pigmentosum patient in complementation group A, suggest that isolated G:C to A:T somatic mutations may be particularly important in generation of human skin cancer by UV radiation.« less

Wavelength-dependent ultraviolet induction of cyclobutane pyrimidine dimers in the human cornea.

PubMed

Mallet, Justin D; Rochette, Patrick J

2013-08-01

Exposition to ultraviolet (UV) light is involved in the initiation and the progression of skin cancer. The genotoxicity of UV light is mainly attributed to the induction of cyclobutane pyrimidine dimers (CPDs), the most abundant DNA damage generated by all UV types (UVA, B and C). The human cornea is also exposed to the harmful UV radiations, but no UV-related neoplasm has been reported in this ocular structure. The probability that a specific DNA damage leads to a mutation and eventually to cellular transformation is influenced by its formation frequency. To shed light on the genotoxic effect of sunlight in the human eye, we have analyzed CPD induction in the cornea and the iris following irradiation of ex vivo human eyes with UVA, B or C. The extent of CPD induction was used to establish the penetrance of the different UV types in the human cornea. We show that UVB- and UVC-induced CPDs are concentrated in the corneal epithelium and do not penetrate deeply beyond this corneal layer. On the other hand, UVA wavelengths penetrate deeper and induce CPDs in the entire cornea and in the first layers of the iris. Taken together, our results are undoubtedly an important step towards better understanding the consequences of UV exposure to the human eye.

Are there mechanistic differences between ultraviolet and visible radiation induced skin pigmentation?

PubMed

Ramasubramaniam, Rajagopal; Roy, Arindam; Sharma, Bharati; Nagalakshmi, Surendra

2011-12-01

Most of the studies on sunlight-induced pigmentation of skin are mainly focused on ultraviolet (UV) radiation-induced pigmentation and ways to prevent it. Recent studies have shown that the visible component of sunlight can also cause significant skin pigmentation. In the current study, the extent of pigmentation induced by UV and visible regions of sunlight in subjects with Fitzpatrick skin type IV-V was measured and compared with pigmentation induced by total sunlight. The immediate pigment darkening (IPD) induced by the visible fraction of sunlight is not significantly different from that induced by the UV fraction. However, the persistent pigment darkening (PPD) induced by visible fraction of sunlight in significantly lower than that induced by the UV fraction. The dose responses of IPD induced by UV, visible light and total sunlight suggest that both UV and visible light interact with the same precursor although UV is 25 times more efficient in inducing pigmentation per J cm(-2) of irradiation compared to visible radiation. The measured diffused reflection spectra and decay kinetics of UV and visible radiation-induced pigmentation are very similar, indicating that the nature of the transient and persistent species involved in both the processes are also likely to be same.

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.

A Real-Time Ultraviolet Radiation Imaging System Using an Organic Photoconductive Image Sensor†

PubMed Central

Okino, Toru; Yamahira, Seiji; Yamada, Shota; Hirose, Yutaka; Odagawa, Akihiro; Kato, Yoshihisa; Tanaka, Tsuyoshi

2018-01-01

We have developed a real time ultraviolet (UV) imaging system that can visualize both invisible UV light and a visible (VIS) background scene in an outdoor environment. As a UV/VIS image sensor, an organic photoconductive film (OPF) imager is employed. The OPF has an intrinsically higher sensitivity in the UV wavelength region than those of conventional consumer Complementary Metal Oxide Semiconductor (CMOS) image sensors (CIS) or Charge Coupled Devices (CCD). As particular examples, imaging of hydrogen flame and of corona discharge is demonstrated. UV images overlapped on background scenes are simply made by on-board background subtraction. The system is capable of imaging weaker UV signals by four orders of magnitude than that of VIS background. It is applicable not only to future hydrogen supply stations but also to other UV/VIS monitor systems requiring UV sensitivity under strong visible radiation environment such as power supply substations. PMID:29361742

PHOTOACTIVATED TOXICITY IN AQUATIC ENVIRONMENTS

EPA Science Inventory

Most aquatic organisms have evolved mechanisms to minimize damage by ultraviolet (UV) radiation. Many terrestrial species have additionally had to adapt to plant compounds (e.g. furanocoumarins) that are extremely toxic when activated by UV radiation. Over evolutionary time, it i...

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.

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.

Effects of elevated ultraviolet radiation on primary metabolites in selected alpine algae and cyanobacteria

PubMed Central

Hartmann, Anja; Albert, Andreas; Ganzera, Markus

2015-01-01

Extremophilic green algae and cyanobacteria are the most abundant species in high mountain habitats, where rough climate conditions such as temperature differences, limited water retention and high ultraviolet (UV) radiation are the cause for a restricted biological diversity in favor of a few specialized autotrophic microorganisms. In this study, we investigated four algal species from alpine habitat in a sun simulator for their defense strategies in response to UV-A radiation (315–400 nm) up to 13.4 W/m2 and UV-B radiation (280–315 nm) up to 2.8 W/m2. Besides changes in pigment composition we discovered that primary polar metabolites like aromatic amino acids, nucleic bases and nucleosides are increasingly produced when the organisms are exposed to elevated UV radiation. Respective compounds were isolated and identified, and in order to quantify them an HPLC-DAD method was developed and validated. Our results show that especially tyrosine and guanosine were found to be generally two to three times upregulated in the UV-B exposed samples compared to the non-treated control. PMID:26065817

Drinking water treatment with ultraviolet light for travelers -- Evaluation of a mobile lightweight system.

PubMed

Timmermann, Lisa F; Ritter, Klaus; Hillebrandt, David; Küpper, Thomas

2015-01-01

The SteriPEN(®) is a handheld device for disinfecting water with ultraviolet (UV) radiation. The manufacturer claims a reduction of at least 99.9% of bacteria, viruses, and protozoa. The present study intends to verify the general effectiveness of the device. Furthermore, the influence of bottle geometry and water movement is examined and the issue of user safety with regard to UV-C radiation is addressed. The device was applied on water containing a known number of microorganisms (Escherichia coli, Staphylococcus aureus, and the spore of Geobacillusstearothermophilus) and the survival rate was examined. Three different types of bottles commonly used among travelers served as test containers. All tests were conducted with and without agitating the water during irradiation. Furthermore, a spectral analysis was performed on the light of the device. The SteriPEN(®) reached a mean reduction of more than 99.99% of bacteria and 99.57% of the spores when applied correctly. However, the results of the trials without agitating the water only yielded a 94.98% germ reduction. The device's maximal radiation intensity lies at 254 nm which is the wavelength most efficient in inactivating bacteria. The UV-C fraction is filtered out completely by common bottle materials. However, when applied in larger containers a portion of the UV-C rays exits the water surface. If applied according to the instructions the device manages a satisfactory inactivation of bacteria. However, it bears the danger of user errors relevant to health. Therefore, education on the risks of incorrect application should be included in the travel medical consultation. Also there are still aspects that need to be subject to further independent research. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

PROBABILISTIC RISK ASSESSMENT FOR THE EFFECTS OF SOLAR ULTRAVIOLET RADIATION ON AMPHIBIANS

EPA Science Inventory

Several studies have demonstrated that exposure to solar ultraviolet (UV) radiation can cause elevated mortality and an increased prevalence of eye and limb malformations in developing amphibian larvae. From these observations scientists have hypothesized that recent increases in...

PARTIAL INHIBITION OF IN VITRO POLLEN GERMINATION BY SIMULATED SOLAR ULTRAVIOLET-B RADIATION

EPA Science Inventory

Pollen from four temperate-latitude taxa were treated with UV radiation in a portion of the UV-B (280-320 nm) waveband during in vitro germination. Inhibition of germination was noted in this pollen compared to samples treated identically except for the exclusion of the UV-B port...

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 ...

Potential apoptotic effect of ultraviolet-A irradiation during cross-linking: a study on ex vivo cultivated limbal epithelial cells.

PubMed

Matalia, Himanshu; Shetty, Rohit; Dhamodaran, Kamesh; Subramani, Murali; Arokiaraj, Vincent; Das, Debashish

2012-10-01

To study the effects of ultraviolet-A (UV-A) irradiation, in the presence or absence of riboflavin, on ex vivo cultured limbal epithelial cells (LECs). The study was carried out in a super specialty ophthalmic hospital. Ex vivo cultured LECs were grown on denuded amniotic membranes and exposed to similar levels of UV-A radiation used during corneal cross-linking (CXL), in the presence or absence of the photosensitiser, riboflavin. These cells were then used for extraction of RNA, cDNA conversion, and antibody staining. Quantitative PCR and immunofluorescence staining were performed to evaluate the apoptotic state of treated and non-treated LECs. Statistical analyses were evaluated using a Student's t test. We found that bcl-2, an antiapoptotic gene, was downregulated, whereas, bax, a proapoptotic gene, was upregulated. After LECs were exposed to UV-A radiation, a significant upregulation of both caspase 3 and caspase 9 was observed in treated cells when compared with untreated LECs. These results indicate that exposure of LECs to UV-A dosages similar to those used in the CXL procedure promotes the expression of genes known to promote apoptosis. In the presence of riboflavin, the damage caused by UV-A treatment was marginalised, but not totally blocked.

Potential effects of ultraviolet radiation reduction on tundra nitrous oxide and methane fluxes in maritime Antarctica.

PubMed

Bao, Tao; Zhu, Renbin; Wang, Pei; Ye, Wenjuan; Ma, Dawei; Xu, Hua

2018-02-27

Stratospheric ozone has begun to recover in Antarctica since the implementation of the Montreal Protocol. However, the effects of ultraviolet (UV) radiation on tundra greenhouse gas fluxes are rarely reported for Polar Regions. In the present study, tundra N 2 O and CH 4 fluxes were measured under the simulated reduction of UV radiation in maritime Antarctica over the last three-year summers. Significantly enhanced N 2 O and CH 4 emissions occurred at tundra sites under the simulated reduction of UV radiation. Compared with the ambient normal UV level, a 20% reduction in UV radiation increased tundra emissions by an average of 8 μg N 2 O m -2 h -1 and 93 μg CH 4 m -2 h -1 , whereas a 50% reduction in UV radiation increased their emissions by an average of 17 μg N 2 O m -2 h -1 and 128 μg CH 4 m -2 h -1 . No statistically significant correlation (P > 0.05) was found between N 2 O and CH 4 fluxes and soil temperature, soil moisture, total carbon, total nitrogen, NO 3 - -N and NH 4 + -N contents. Our results confirmed that UV radiation intensity is an important factor affecting tundra N 2 O and CH 4 fluxes in maritime Antarctica. Exclusion of the effects of reduced UV radiation might underestimate their budgets in Polar Regions with the recovery of stratospheric ozone.

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.

Solar ultraviolet radiation is necessary to enhance grapevine fruit ripening transcriptional and phenolic responses.

PubMed

Carbonell-Bejerano, Pablo; Diago, Maria-Paz; Martínez-Abaigar, Javier; Martínez-Zapater, José M; Tardáguila, Javier; Núñez-Olivera, Encarnación

2014-07-09

Ultraviolet (UV) radiation modulates secondary metabolism in the skin of Vitis vinifera L. berries, which affects the final composition of both grapes and wines. The expression of several phenylpropanoid biosynthesis-related genes is regulated by UV radiation in grape berries. However, the complete portion of transcriptome and ripening processes influenced by solar UV radiation in grapes remains unknown. Whole genome arrays were used to identify the berry skin transcriptome modulated by the UV radiation received naturally in a mid-altitude Tempranillo vineyard. UV radiation-blocking and transmitting filters were used to generate the experimental conditions. The expression of 121 genes was significantly altered by solar UV radiation. Functional enrichment analysis of altered transcripts mainly pointed out that secondary metabolism-related transcripts were induced by UV radiation including VvFLS1, VvGT5 and VvGT6 flavonol biosynthetic genes and monoterpenoid biosynthetic genes. Berry skin phenolic composition was also analysed to search for correlation with gene expression changes and UV-increased flavonols accumulation was the most evident impact. Among regulatory genes, novel UV radiation-responsive transcription factors including VvMYB24 and three bHLH, together with known grapevine UV-responsive genes such as VvMYBF1, were identified. A transcriptomic meta-analysis revealed that genes up-regulated by UV radiation in the berry skin were also enriched in homologs of Arabidopsis UVR8 UV-B photoreceptor-dependent UV-B -responsive genes. Indeed, a search of the grapevine reference genomic sequence identified UV-B signalling pathway homologs and among them, VvHY5-1, VvHY5-2 and VvRUP were up-regulated by UV radiation in the berry skin. Results suggest that the UV-B radiation-specific signalling pathway is activated in the skin of grapes grown at mid-altitudes. The biosynthesis and accumulation of secondary metabolites, which are appreciated in winemaking and potentially confer cross-tolerance, were almost specifically triggered. This draws attention to viticultural practices that increase solar UV radiation on vineyards as they may improve grape features.

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.

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.

Responses of photosynthetic properties and chloroplast ultrastructure of Bryum argenteum from a desert biological soil crust to elevated ultraviolet-B radiation.

PubMed

Hui, Rong; Li, Xinrong; Chen, Cuiyun; Zhao, Xin; Jia, Rongliang; Liu, Lichao; Wei, Yongping

2013-04-01

Our understanding of plant responses to enhanced ultraviolet-B (UV-B) radiation has improved over recent decades. However, research on cryptogams is scarce and it remains controversial whether UV-B radiation causes changes in physiology related to photosynthesis. To investigate the effects of supplementary UV-B radiation on photosynthesis and chloroplast ultrastructure in Bryum argenteum Hedw., specimens were cultured for 10 days under four UV-B treatments (2.75, 3.08, 3.25 and 3.41 W m(-2) ), simulating depletion of 0% (control), 6%, 9% and 12% of stratospheric ozone at the latitude of Shapotou, a temperate desert area of northwest China. Analyses showed malondialdehyde content significantly increased, whereas chlorophyll (Chl) fluorescence parameters and Chl contents decreased with increased UV-B intensity. These results corresponded with changes in thylakoid protein complexes and chloroplast ultrastructure. Overall, enhanced UV-B radiation leads to significant decreases in photosynthetic function and serious destruction of the chloroplast ultrastructure of B. argenteum. The degree of negative influences increased with the intensity of UV-B radiation. These results may not only provide a potential mechanism for supplemental UV-B effects on photosynthesis of moss crust, but also establish a theoretical basis for further studies of adaptation and response mechanisms of desert ecosystems under future ozone depletion. Copyright © Physiologia Plantarum 2012.

Ultraviolet-B Protective Effect of Flavonoids from Eugenia caryophylata on Human Dermal Fibroblast Cells.

PubMed

Patwardhan, Juilee; Bhatt, Purvi

2015-10-01

The exposure of skin to ultraviolet-B (UV-B) radiations leads to deoxyribonucleic acid (DNA) damage and can induce production of free radicals which imbalance the redox status of the cell and lead to increased oxidative stress. Clove has been traditionally used for its analgesic, anti-inflammatory, anti-microbial, anti-viral, and antiseptic effects. To evaluate the UV-B protective activity of flavonoids from Eugenia caryophylata (clove) buds on human dermal fibroblast cells. Protective ability of flavonoid-enriched (FE) fraction of clove was studied against UV-B induced cytotoxicity, anti-oxidant regulation, oxidative DNA damage, intracellular reactive oxygen species (ROS) generation, apoptotic morphological changes, and regulation of heme oxygenase-1 (HO-1) gene through nuclear factor E2-related factor 2 antioxidant response element (Nrf2 ARE) pathway. FE fraction showed a significant antioxidant potential. Pretreatment of cells with FE fraction (10-40 μg/ml) reversed the effects of UV-B induced cytotoxicity, depletion of endogenous enzymatic antioxidants, oxidative DNA damage, intracellular ROS production, apoptotic changes, and overexpression of Nrf2 and HO-1. The present study demonstrated for the first time that the FE fraction from clove could confer UV-B protection probably through the Nrf2-ARE pathway, which included the down-regulation of Nrf2 and HO-1. These findings suggested that the flavonoids from clove could potentially be considered as UV-B protectants and can be explored further for its topical application to the area of the skin requiring protection. Pretreatment of human dermal fibroblast with flavonoid-enriched fraction of Eugenia caryophylata attenuated effects of ultraviolet-B radiationsIt also conferred protection through nuclear factor E2-related factor 2-antioxidant response pathway and increased tolerance of cells against oxidative stressFlavonoid-enriched fraction can be explored further for topical application to the skin as a ultraviolet-B protectant. Abbreviations used: ABTS: 2,2'-azino-bis-(3-ethylbenzothiazoline- 6-sulphonic acid), AO: Acridine orange, Analysis of variance, ARE: Antioxidant response elements, BSA: Bovine serum albumin, CAPE: Caffeic acid phenethyl ester, CAT: Catalase, DCFH-DA: 2',7'-dichlorofluorescein diacetate, DMEM: Dulbecco's Modified Eagle's Medium, DMSO: Dimethyl sulfoxide, DNA: Deoxyribonucleic acid, DPBS: Dulbecco's phosphate buffered saline, DPPH: 2,2-diphenyl-1-picrylhydrazyl, ECL: Enhanced chemiluminescence, EDTA: Ethylenediaminetetraacetic acid, ELISA: Enzyme-linked immunesorbent assay, EtBr: Ethidium bromide, FBS: Fetal bovine serum, FE fraction: Flavonoid-enriched fraction, FRAP: Ferric reducing antioxidant power, GPx: Glutathione peroxidase, GR: Glutathione reductase, GST: Glutathione-S-transferase, GSH: Reduced glutathione, GSSG: Oxidized glutathione, HDF: Human dermal fibroblast, HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid, HRP: Horseradish peroxidase, HO-1: Heme oxygenase-1, HPTLC: High-performance thin layer chromatography, Keap-1: Kelch-like ECH-associated protein-1, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, NaCl: Sodium chloride, NFDM: Nonfat dry milk, Nrf2: Nuclear factor E2-related factor 2, NQO1: NAD (P) H: Quinine oxidoreductase 1, OH: Hydroxyl ions, PBST: Phosphate buffered saline with 0.1% tween 20, PCR: Polymerase chain reaction, PMSF: Phenylmethanesulfonyl fluoride, Rf: Retention factor, ROS: Reactive oxygen species, rRNA: Ribosomal ribonucleic acid, SDS: Sodium dodecyl sulfate, SOD: Superoxide dismutase, TLC: Thin layer chromatography, TLC-DPPH: Thin layer chromatography-2,2-diphenyl-1-picrylhydrazyl, UV: Ultraviolet, UV-A: Ultraviolet-A, UV-B: Ultraviolet-B, UV-C: Ultraviolet-C, and qPCR: Quantitative polymerase chain reaction.

Glacial Influences on Solar Radiation in a Subarctic Sea.

EPA Science Inventory

Understanding macroscale processes controlling solar radia­tion in marine systems will be important in interpreting the potential effects of global change from increasing ultraviolet radiation (UV) and glacial retreat. This study provides the first quantitative assessment of UV i...

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.

[Association between sunburn in children and ultraviolet radiation and ozone layer, during six summers (1996-2001) in Santiago, Chile (33,5 degrees S)].

PubMed

Aranibar, Ligia; Cabrera, Sergio; Honeyman, Juan

2003-09-01

During the recent 10 years the ozone layer has decreased while ultraviolet radiation has increased in Santiago, Chile. To determine whether the number of sunburns in children correlate with ultraviolet radiation in Santiago. During six Austral Summers (1996-2001) children below 15 years old, consulting for sunburn, were evaluated at the "Corporation for the Aid of Burned Children" (COANIQUEM) in Santiago (33.5 degrees S). The number of children with sunburns during each Summer was compared with the corresponding UV-B radiation and the ozone thickness, to establish a probable relation between a geophysical change and its consequences in skin health. The ozone layer values were obtained from the NASA WEB-page and the ultraviolet radiation was measured with a four-channel medium resolution radiometer. In each Summer there was a predominance of sunburns among boys and among ages between 6 and 10 years. During the 96-97 Austral Summer, the highest number of children with sunburns (63) was diagnosed. That Summer also had the highest mean UV-305 nm radiation with an important amount of days with ozone < or = 260 Dobson Units. Only during that Summer an inverse correlation between ozone and UV-305 nm radiation was detected. At the same time the maximal values of Erythemal Dose Rate (33 muWatt cm2), UV Index (13) and Erythemal Daily Dose (7.500 Joule m2) were observed. In Santiago, Summers with a higher number of days with low ozone protection seem to reappear every 3 years. Understanding the interaction of physical processes that control the ozone layer, may help to design better photo-protection programs for human health.

ADVANCED OXIDATION PROCESS TECHNOLOGY (ULTRAVIOLET RADIATION/OZONE TREATMENT) FOR REMOVAL OF METHYL TERTIARY BUTYL ETHER (MTBE) IN GROUND WATER SUPPLIES.

EPA Science Inventory

U.S. EPA’s Office of Research and Development in Cincinnati, Ohio has been testing and evaluating MTBE removal in dechlorinated tap water using three oxidant combinations: hydrogen peroxide/ozone, ultraviolet irradiation (UV)/ozone, and UV/ozone/hydrogen peroxide. Pilot-scale st...

Spatial and Temporal Variability of Solar Ultraviolet Exposure of Coral Assemblages in the Florida Keys: Importance of Colored Dissolved Organic Matter x

EPA Science Inventory

Solar ultraviolet (UV) radiation can have deleterious effects on coral assemblages in tropical and subtropical marine environments, but little information is available on UV penetration into ocean waters surrounding corals. Here we provide an extensive data set of optical propert...

The effects of ultraviolet radiation on growth and bleaching in three species of Hawaiian coral

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

Goodman, G.D.

1990-01-09

Long term exposure to ultraviolet radiation is harmful to many organisms, including hermatypic corals, which obtain much of their nutrition from photosynthetic zooxanthellae. Therefore, increased UV radiation from atmospheric ozone depletion could inhibit growth of such corals. Moreover, coral bleaching, which has been attributed to loss of pigment and/or expulsion of zooxanthellae, may be a specific response to UV light. Does UV-A reduce skeletal growth or influence population density and pigment content of zooxanthellae In addition, do zooxanthellae migrate to shaded areas of the colony to avoid ultraviolet light Using alizarin red stain and suitable filters, I compared the stainmore » and suitable filters, I compared the effects of UV-A (320-400nm) and full-spectrum UV (280-400nm) on the skeletal growth of two Hawaiian corals, Montipora verrucosa, Pocillopora damicornis, in situ. In the perforate corals, M. Verrucosa and Porites compressa, I measured concentration of zooxanthellae and their chlorophyll content to quantify bleaching in response to UV light. Reduction in skeletal growth by the two corals in response to different ranges of UV light appears to be species specific. Bleaching by UV appears to be characterized by an initial loss of pigment followed by the expulsion and migration of the zooxanthellae to shaded areas of the colony. Differences in tolerance and adaptation to decreasing ozone levels and increasing UV light should confer a competitive advantage on various species and morphologies of reef-building corals.« less

Ultraviolet disinfection of water for small water supplies

NASA Astrophysics Data System (ADS)

Carlson, D. A.; Seabloom, R. W.; Dewalle, F. B.; Wetzler, T. F.; Engeset, J.

1985-07-01

In the study ultraviolet radiation was considered as an alternative means of disinfection of small drinking water supplies. A major impetus for the study was the large increase in waterborne disease episodes in the United States whose etiologic agent, Giardia lamblia, was found to be highly resistant to conventional chlorination. While the germicidal effect of sunlight has long been known, it has been found that artificial UV radiation with a wavelength of 253.7 nm, can be produced by low pressure mercury vapor lamps. The inactivation of microorganisms by UV radiation is based upon photochemical reactions in DNA which result in errors in the coding system. Inactivation of microorganisms due to exposure to UV is proportional to the intensity multiplied by the time of exposure.

Determination of 2-alkylcyclobutanones in ultraviolet light-irradiated fatty acids, triglycerides, corn oil, and pork samples: Identifying a new source of 2-alkylcyclobutanones.

PubMed

Meng, Xiangpeng; Chan, Wan

2017-02-15

Previous studies have established that 2-alkylcyclobutanones (2-ACBs) are unique radiolytic products in lipid-containing foods that could only be formed through exposure to ionizing radiation, but not by any other means of physical/heat treatment methods. Therefore, 2-ACBs are currently the marker molecules required by the European Committee for Standardization to be used to identify foods irradiated with ionizing irradiation. Using a spectrum of state-of-the-art analytical instruments, we present in this study for the first time that the generation of 2-ACBs was also possible when fatty acids and triglycerides are exposed to a non-ionizing, short-wavelength ultraviolet (UV-C) light source. An irradiation dosage-dependent formation of 2-ACBs was also observed in UV-C irradiated fatty acids, triglycerides, corn oil, and pork samples. With UV-C irradiation becoming an increasingly common food treatment procedure, it is anticipated that the results from this study will alert food scientists and regulatory officials to a potential new source for 2-ACBs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tea, coffee, and cocoa as ultraviolet radiation protectants for beet armyworm nucleopolyhedrovirus

USDA-ARS?s Scientific Manuscript database

The addition of 1% (wt/v) aqueous extracts of cocoa (Theobroma cacao L.) (Malvales: Malvaceae), coffee (Coffea arabica L.) (Gentianales: Rubiaceae), green, and black tea (Camellia sinensis L.) (Ericales: Theaceae) provided excellent ultraviolet (UV) radiation protection for the beet armyworm, Spodo...

Ultraviolet-B and photosynthetically active radiation interactively affect yield and pattern of monoterpenes in leaves of peppermint (Mentha x piperita L.).

PubMed

Behn, Helen; Albert, Andreas; Marx, Friedhelm; Noga, Georg; Ulbrich, Andreas

2010-06-23

Solar radiation is a key environmental signal in regulation of plant secondary metabolism. Since metabolic responses to light and ultraviolet (UV) radiation exposure are known to depend on the ratio of spectral ranges (e.g., UV-B/PAR), we examined effects of different UV-B radiation (280-315 nm) and photosynthetically active radiation (PAR, 400-700 nm) levels and ratios on yield and pattern of monoterpenoid essential oil of peppermint. Experiments were performed in exposure chambers, technically equipped for realistic simulation of natural climate and radiation. The experimental design comprised four irradiation regimes created by the combination of two PAR levels including or excluding UV-B radiation. During flowering, the highest essential oil yield was achieved at high PAR (1150 micromol m(-2) s(-1)) and approximate ambient UV-B radiation (0.6 W m(-2)). Regarding the monoterpene pattern, low PAR (550 micromol m(-2) s(-1)) and the absence of UV-B radiation led to reduced menthol and increased menthone contents and thereby to a substantial decrease in oil quality. Essential oil yield could not be correlated with density or diameter of peltate glandular trichomes, the epidermal structures specialized on biosynthesis, and the accumulation of monoterpenes. The present results lead to the conclusion that production of high quality oils (fulfilling the requirements of the Pharmacopoeia Europaea) requires high levels of natural sunlight. In protected cultivation, the use of UV-B transmitting covering materials is therefore highly recommended.

Radiative lifetimes in B I using ultraviolet and vacuum-ultraviolet laser-induced fluorescence

NASA Technical Reports Server (NTRS)

O'Brian, T. R.; Lawler, J. E.

1992-01-01

Radiative lifetimes of the eight lowest even parity levels in the doublet system of B I are measured using time-resolved laser-induced fluorescence in the UV and VUV on an atomic beam of boron. The accurate lifetimes provide a base for improved determination of absolute transition probabilities in B I. The techniques described are broadly applicable to measurement of lifetimes of levels with transitions in the visible, UV, and VUV in almost any element.

Influence of clouds on UV-B penetration to the earth's surface

NASA Technical Reports Server (NTRS)

Green, A. E. S.

1979-01-01

Radiometric measurements of cloud influence on ultraviolet B radiation (UV-B) were obtained. Mathematical models of the influence were defined to lay the groundwork for the construction of the global UV-B climatology from satellite determined ozone data. More refined measurements comparing UV-B radiation with total solar radiation were carried out. The cloudy case is referred to the cloudless sky irradiance and convenient transmission ratios are given An approach to the inversion of scattering data is summarized. An improved characterization of the UV-B radiation from a cloudless sky is also presented.

Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America*

PubMed Central

Corrêa, Marcelo de Paula

2015-01-01

The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures. PMID:26131858

Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America.

PubMed

Corrêa, Marcelo de Paula

2015-01-01

The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures.

Further comparison of MODTRAN 5 to measured data in the UV band

NASA Astrophysics Data System (ADS)

Smith, Leon; Richardson, Mark; Ayling, Richard; Barlow, Nick

2014-10-01

The ability to accurately model background radiation from the sun is important in understanding the operation of missile systems with ultraviolet (UV) guard channels. In theory a missile system's UV channel detects a target's silhouette, caused by its `negative contrast' with respect to background UV radiation. The variation in background levels of UV will therefore have an effect on the operability of a missile system that utilises a UV channel. In this paper an update on the measurement and comparison of background UV-A radiation to data produced by Moderate Resolution Atmospheric Transmission 5 (MODTRAN®5) is given. In the past surface flux and radiance data calculated using MODTRAN®5 has been compared to data from the World Ozone and Ultraviolet Data Centre (WOUDC) archive, and measurements taken by the author at the Defence Academy of the UK. With the aid of spectral measurement equipment, new measurements have been made and compared with the radiance profiles produced by MODTRAN®5, including measurements made throughout both winter and summer months. Also discussed are the effects of scattering and absorption by different cloud types on the amount of radiation observed at the Earth's surface.

Effects of ultraviolet light on biogenic amines and other quality indicators of chicken meat during refrigerated storage.

PubMed

Lázaro, C A; Conte-Júnior, C A; Monteiro, M L G; Canto, A C V S; Costa-Lima, B R C; Mano, S B; Franco, R M

2014-09-01

Radiation from UV-C has been demonstrated as a potential surface decontamination method in addition to several advantages over regular sanitation methods. However, UV-C radiation possibly affects the physicochemical properties of meat products. To determine the optimum exposure time for bacterial reduction, 39 chicken breasts, inoculated with a pool of Salmonella spp., were submitted to 3 levels of UV-C intensities (0.62, 1.13, and 1.95 mW/cm²) for up to 120 s. After the optimum exposure time of 90 s was determined, changes in the biogenic amines, total aerobic mesophilic bacteria, Enterobacteriaceae, lipid oxidation, pH, and instrumental color were evaluated in 84 chicken breasts that were irradiated (0.62, 1.13, and 1.95 mW/cm²) and stored at 4°C for 9 d. The groups treated with UV-C radiation exhibited an increase in tyramine, cadaverine, and putrescine contents (P < 0.05). The highest UV-C intensity (1.95 mW/cm²) promoted a decrease in the initial bacterial load, and extended the lag phase and the shelf life. The groups irradiated with 1.13 and 1.95 mW/cm² exhibited a more stable b* value than the other groups; similar trends for L*, a*, pH, and TBA reactive substance values were observed among all groups. The UV-C light was demonstrated to be an efficient alternative technology to improve the bacteriological quality of chicken meat without negatively affecting the physical and chemical parameters of chicken breast meat. Nonetheless, the increases on the biogenic amines content should be considered as an effect of the UV processing and not as an indicator of bacterial growth. © 2014 Poultry Science Association Inc.

[Analysis of the cumulative solar ultraviolet radiation in Mexico].

PubMed

Castanedo-Cázares, Juan Pablo; Torres-Álvarez, Bertha; Portales-González, Bárbara; Martínez-Rosales, Karla; Hernández-Blanco, Diana

2016-01-01

The incidence of skin cancer has increased in Mexico in recent years. Ultraviolet radiation is the main risk factor associated. Due to the need to develop strategies to prevent skin cancer, the aim of the study was to estimate the UV intensity in several representative regions of Mexico, the average annual UV dose of these populations, and the potential benefit of applying sunscreen at different ages. The intensity of UV radiation was quantified by remote and terrestrial radiometry. The dose of UV exposure was measured in minimal erythema doses using validated models for face and arms. The benefit of using a sunscreen was calculated with the use of a sunscreen with SPF 15 from birth to age 70. The UV radiation is lower in December and greater in the period from May to July. The region with a lower annual dose is Tijuana; and the higher annual dose is in the Mexico City area. The annual difference between these regions was 58 %. Through life, a low SPF sunscreen can reduce up to 66 % of the received UV dose. The geographical location is a risk factor for accumulation of UV radiation in Mexico. Since childhood, people receive high amounts of it; however, most of this dose can be reduced using any commercially available sunscreen, if applied strategically.

Occupational Exposure to Ultraviolet Radiation and Risk of Non-Melanoma Skin Cancer in a Multinational European Study

PubMed Central

Surdu, Simona; Fitzgerald, Edward F.; Bloom, Michael S.; Boscoe, Francis P.; Carpenter, David O.; Haase, Richard F.; Gurzau, Eugen; Rudnai, Peter; Koppova, Kvetoslava; Févotte, Joëlle; Leonardi, Giovanni; Vahter, Marie; Goessler, Walter; Kumar, Rajiv; Fletcher, Tony

2013-01-01

Background Studies suggest that ambient sunlight plays an important role in the pathogenesis of non-melanoma skin cancers (NMSC). However, there is ongoing controversy regarding the relevance of occupational exposure to natural and artificial ultraviolet radiation (UV) radiation. Objectives We investigated potential associations between natural and artificial UV radiation exposure at work with NMSC in a case-control study conducted in Hungary, Romania, and Slovakia. Methods Occupational exposures were classified by expert assessment for 527 controls and 618 NMSC cases (515 basal cell carcinoma, BCC). Covariate information was collected via interview and multiple logistic regression models were used to assess associations between UV exposure and NMSC. Results Lifetime prevalence of occupational exposure in the participants was 13% for natural UV radiation and 7% for artificial UV radiation. Significant negative associations between occupational exposure to natural UV radiation and NMSC were detected for all who had ever been exposed (odds ratio (OR) 0.47, 95% confidence interval (CI) 0.27–0.80); similar results were detected using a semi-quantitative metric of cumulative exposure. The effects were modified by skin complexion, with significantly decreased risks of BCC among participants with light skin complexion. No associations were observed in relation to occupational artificial UV radiation exposure. Conclusions The protective effect of occupational exposure to natural UV radiation was unexpected, but limited to light-skinned people, suggesting adequate sun-protection behaviors. Further investigations focusing on variations in the individual genetic susceptibility and potential interactions with environmental and other relevant factors are planned. PMID:23638051

POTENTIAL IMPACTS OF INCREASED SOLAR UV-B ON GLOBAL PLANT PRODUCTIVITY

EPA Science Inventory

Ultraviolet-B radiation comprises only a small portion of the electromagnetic spectrum but has a disproportionately large photobiological effect. oth plants and animals are greatly affected by increases in UV-B radiation but there exists tremendous variability in the sensitivity ...

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.

ASSESSMENT OF THE RISK OF SOLAR ULTRAVIOLET RADIATION TO AMPHIBIANS: III. PREDICTION OF IMPACTS IN SELECTED NORTHERN MIDWESTERN WETLANDS

EPA Science Inventory

The deleterious effects of solar ultraviolet radiation, especially the UV-B portion of sunlight, have been hypothesized to reduce survival, increase the frequency of malformations, and contribute to the apparent worldwide decline of many amphibian species.

Effects of ultraviolet (UV) irradiation in air and under vacuum on low-k dielectrics

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

Choudhury, F. A.; Nguyen, H. M.; Shohet, J. L., E-mail: shohet@engr.wisc.edu

This work addresses the effect of ultraviolet radiation of wavelengths longer than 250 nm on Si-CH{sub 3} bonds in porous low-k dielectrics. Porous low-k films (k = 2.3) were exposed to 4.9 eV (254 nm) ultraviolet (UV) radiation in both air and vacuum for one hour. Using Fourier Transform Infrared (FTIR) spectroscopy, the chemical structures of the dielectric films were analyzed before and after the UV exposure. UV irradiation in air led to Si-CH{sub 3} bond depletion in the low-k material and made the films hydrophilic. However, no change in Si-CH{sub 3} bond concentration was observed when the same samplesmore » were exposed to UV under vacuum with a similar fluence. These results indicate that UV exposures in vacuum with wavelengths longer than ∼250 nm do not result in Si-CH{sub 3} depletion in low-k films. However, if the irradiation takes place in air, the UV irradiation removes Si-CH{sub 3} although direct photolysis of air species does not occur above ∼242 nm. We propose that photons along with molecular oxygen and, water, synergistically demethylate the low-k films.« less

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

PubMed

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

2015-04-15

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

Long-Term Survival Phase Cells of Salmonella Typhimurium ATCC 14028 Have Significantly Greater Resistance to Ultraviolet Radiation in 0.85% Saline and Apple Juice.

PubMed

Wang, Fei; Mendonça, Aubrey; Brehm-Stecher, Byron F; Dickson, James; DiSpirito, Alan; Shaw, Angela; Thomas-Popo, Emalie

2018-05-31

Nonendospore-forming pathogenic bacteria in the long-term survival (LTS) phase can remain viable for months or years and may show reduced susceptibility to various antimicrobial interventions. In the present study, we investigated the response of LTS phase Salmonella enterica serovar Typhimurium (ATCC 14028) to ultraviolet (UV) radiation in 0.85% (w/v) saline and apple juice and the extent of sublethal injury in LTS phase survivors. The LTS-phase Salmonella Typhimurium cells were cultured at 35°C for 14 days in tryptic soy broth with 0.6% (w/v) yeast extract (TSBYE). Exponential- and stationary-phase cells, cultured in TSBYE (35°C) for 2.5 and 18 h, respectively, served as control samples. Cells (10 7 CFU [colony-forming unit]/mL) from each physiological state were exposed to UV light in saline (80 μW/cm 2 ) and apple juice (1500 μW/cm 2 ). The Salmonella Typhimurium survivors were plated for enumeration on either tryptic soy agar with 0.6% yeast extract or xylose-lysine-tergitol 4 (XLT4) agar and colonies counted after incubation (35°C, 24 h). Of all the growth phases tested, LTS phase cells were consistently impacted the least by UV treatment (p < 0.05). In saline, D-values of exponential, stationary, and LTS Salmonella Typhimurium were 0.35, 0.38, and 0.49 min, respectively. D-values in apple juice at pH 3.63 and pH 5.65 were 2.52, 3.19, and 3.57 min and 3.24, 3.50, and 4.18 min, respectively. UV radiation (80 μW/cm 2 ) of Salmonella Typhimurium in saline for 2.5 min reduced the number of exponential- and stationary-phase cells by ∼7.19 and 6.30 log 10 CFU/mL, respectively. In contrast, LTS cells were only reduced by 5.08 log 10 CFU/mL. Among the three physiological states, LTS phase cells had the least sublethal injury in the surviving population (p < 0.05). These results indicate that the LTS state cross-protects Salmonella Typhimurium against UV radiation and should be considered in determination of the UV radiation D-value for this pathogen.

The effect of melatonin on eye lens of rats exposed to ultraviolet radiation.

PubMed

Anwar, M M; Moustafa, M A

2001-05-01

We investigated the influence of exogenously administered melatonin on adult rats eye lenses exposed to ultraviolet radiation (UV) A and B ranging from 356-254 nm irradiation at 8 microW/cm(2). Rats exposed to this range of UV for 15 min for one week showed a significant (P<0.05) reduction in antioxidant enzymes activities; superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and elevated (P<0.001) lipid peroxidation served as an index of cellular damage by free radicals. UV-radiation significantly (P<0.001) elevated calcium ions (Ca(2+)) and lactate dehydrogenase (LDH) activity in lenses. Depleting animals of their stores of important intracellular antioxidant and elevating lenticular Ca(2+) by UV irradiation, may be the main cause of lens opacification. Melatonin injection with radiation significantly reduced (P<0.05) lipid peroxidation, Ca(2+) and (P<0.001) for LDH. When melatonin was injected after radiation, SOD and GSH-Px enzyme activities increased significantly (P<0.01), and lipid peroxidation, Ca(2+) levels and LDH activities were reduced significantly. Melatonin injection after UV radiation was as effective as melatonin treatment concurrent with UV irradiation. We conclude that melatonin may protect the eye lens from the damaging effects of UV exposure, and its actions protect lens from oxidative stress, elevating Ca(2+) levels, which are considered as an important causes of cataractogenesis.

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.

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.

Method and apparatus for passive optical dosimeter comprising caged dye molecules

DOEpatents

Sandison, David R.

2001-07-03

A new class of ultraviolet dosimeters is made possible by exposing caged dye molecules, which generate a dye molecule on exposure to ultraviolet radiation, to an exterior environment. Applications include sunburn monitors, characterizing the UV exposure history of UV-sensitive materials, especially including structural plastics, and use in disposable `one-use` optical equipment, especially medical devices.

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.

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 ...

Resistance of a lizard (the green anole, Anolis carolinensis; Polychridae) to ultraviolet radiation-induced immunosuppression

USGS Publications Warehouse

Cope, R.B.; Fabacher, D.L.; Lieske, C.; Miller, C.A.

2001-01-01

The green anole (Anolis carolinensis) is the most northerly distributed of its Neotropical genus. This lizard avoids a winter hibernation phase by the use of sun basking behaviors. Inevitably, this species is exposed to high doses of ambient solar ultraviolet radiation (UVR). Increases in terrestrial ultraviolet-B (UV-B) radiation secondary to stratospheric ozone depletion and habitat perturbation potentially place this species at risk of UVR-induced immunosuppression. Daily exposure to subinflammatory UVR (8 kJ/m2/day UV-B, 85 kJ/m2/day ultraviolet A [UV-A]), 6 days per week for 4 weeks (total cumulative doses of 192 kJ/m2 UV-B, 2.04 × 103 kJ/m2 UV-A) did not suppress the anole's acute or delayed type hypersensitivity (DTH) response to horseshoe crab hemocyanin. In comparison with the available literature UV-B doses as low as 0.1 and 15.9 kJ/m2 induced suppression of DTH responses in mice and humans, respectively. Exposure of anoles to UVR did not result in the inhibition of ex vivo splenocyte phagocytosis of fluorescein labeled Escherichia coli or ex vivo splenocyte nitric oxide production. Doses of UV-B ranging from 0.35 to 45 kJ/m2 have been reported to suppress murine splenic/peritoneal macrophage phagocytosis and nitric oxide production. These preliminary studies demonstrate the resistance of green anoles to UVR-induced immunosuppression. Methanol extracts of anole skin contained two peaks in the ultraviolet wavelength range that could be indicative of photoprotective substances. However, the resistance of green anoles to UVR is probably not completely attributable to absorption by UVR photoprotective substances in the skin but more likely results from a combination of other factors including absorption by the cutis and absorption and reflectance by various components of the dermis.

Impacts of varying light regimes on phycobiliproteins of Nostoc sp. HKAR-2 and Nostoc sp. HKAR-11 isolated from diverse habitats.

PubMed

Kannaujiya, Vinod K; Sinha, Rajeshwar P

2015-11-01

The adaptability of cyanobacteria in diverse habitats is an important factor to withstand harsh conditions. In the present investigation, the impacts of photosynthetically active radiation (PAR; 400-700 nm), ultraviolet-B (UV-B; 280-315 nm), and PAR + UV-B radiations on two cyanobacteria viz., Nostoc sp. HKAR-2 and Nostoc sp. HKAR-11 inhabiting diverse habitats such as hot springs and rice fields, respectively, were studied. Cell viability was about 14 % in Nostoc sp. HKAR-2 and <10 % in Nostoc sp. HKAR-11 after 48 h of UV-B exposure. PAR had negligible negative impact on the survival of both cyanobacteria. The continuous exposure of UV-B and PAR + UV-B showed rapid uncoupling, bleaching, fragmentation, and degradation in both phycocyanin (C-PC) and phycoerythrin (C-PE) subunits of phycobiliproteins (PBPs). Remarkable bleaching effect of C-PE and C-PC was not only observed with UV-B or PAR + UV-B radiation, but longer period (24-48 h) of exposure with PAR alone also showed noticeable negative impact. The C-PE and C-PC subunits of the rice field isolate Nostoc sp. HKAR-11 were severely damaged in comparison to the hot spring isolate Nostoc sp. HKAR-2 with rapid wavelength shifting toward shorter wavelengths denoting the bleaching of both the accessory light harvesting pigments. The results indicate that PBPs of the hot spring isolate Nostoc sp. HKAR-2 were more stable under various light regimes in comparison to the rice field isolate Nostoc sp. HKAR-11 that could serve as a good source of valuable pigments to be used in various biomedical and biotechnological applications.

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.

INFLUENCE OF FLORAL OPTICAL PROPERTIES ON THE ULTRAVIOLET RADIATION ENVIRONMENT OF POLLEN

EPA Science Inventory

Pollen in unopened flowers of most species is totally screened from solar ultraviolet-B radiation by imbricated petals that are largely opaque to UV-B. Following flower opening but before another dehiscence, the anther walls of the species investigated filter out over 98% of the ...

EFFECT OF ARSENICALS ON ULTRAVIOLET-RADIATION-INDUCED GROWTH ARREST AND RELATED SIGNALING EVENTS IN HUMAN KERATINOCYTES

EPA Science Inventory

The molecular mechanisms mediating arsenic-induced carcinogenesis are not well understood. The role of confounding factors such as ultraviolet radiation (UV), add another level of complexity to the study of arsenic carcinogenesis and the cancer risk assessment to humans. We hypot...

REPORT ON GEOGRAPHIC AND SEASONAL VARIABILITY OF UV AFFECTING HUMAN AND ECOLOGICAL HEALTH

EPA Science Inventory

This report takes a look at how effects of ultraviolet radiation changes based on season and location. The data collected by EPA's network of Brewer Spectrophotometer devices was analyzed to determine trends in the flux of ultraviolet radiation at the different Brewer sites acro...

Whales Use Distinct Strategies to Counteract Solar Ultraviolet Radiation

PubMed Central

Martinez-Levasseur, Laura M.; Birch-Machin, Mark A.; Bowman, Amy; Gendron, Diane; Weatherhead, Elizabeth; Knell, Robert J.; Acevedo-Whitehouse, Karina

2013-01-01

A current threat to the marine ecosystem is the high level of solar ultraviolet radiation (UV). Large whales have recently been shown to suffer sun-induced skin damage from continuous UV exposure. Genotoxic consequences of such exposure remain unknown for these long-lived marine species, as does their capacity to counteract UV-induced insults. We show that UV exposure induces mitochondrial DNA damage in the skin of seasonally sympatric fin, sperm, and blue whales and that this damage accumulates with age. However, counteractive molecular mechanisms are markedly different between species. For example, sperm whales, a species that remains for long periods at the sea surface, activate genotoxic stress pathways in response to UV exposure whereas the paler blue whale relies on increased pigmentation as the season progresses. Our study also shows that whales can modulate their responses to fluctuating levels of UV, and that different evolutionary constraints may have shaped their response strategies. PMID:23989080

Effectiveness of eye drops protective against ultraviolet radiation.

PubMed

Daxer, A; Blumthaler, M; Schreder, J; Ettl, A

1998-01-01

To test the effectiveness of commercially available ultraviolet (UV)-protective eye drops (8-hydroxy-1-methylchinolinium methylsulphate) which are recommended for protection against both solar and artificial UV radiation. The spectral transmission in the wavelength range from 250 to 500 nm was investigated in 1-nm steps using a high-resolution double monochromator with holographic gratings of 2,400 lines/mm and a 1,000-watt halogen lamp as light source. The transmission spectrum was measured for different values of the layer thickness. The transmission of a liquid layer of about 10 microns, which corresponds to the thickness of the human tear film, shows a cut-off at 290 nm with a transmission of about 25-50% at shorter wavelengths. For wavelengths longer than 290 nm the transmission is higher than 90%. The threshold time ratio for keratitis formation with and without eye drops is above 0.93 considering solar radiation on the earth's surface and above 0.65 considering radiation from arc-welding, respectively. The transmission spectrum of the eye drops under realistic conditions does not show a protective effect against solar UV radiation. However, there exists reduction of UVC radiation in the spectral range typical of artificial UV sources such as arc-welding. We cannot recommend the application of these eye drops as an UV-protective aid against eye damage by solar UV radiation.

Reduction in cab and psb A RNA transcripts in response to supplementary ultraviolet-B radiation.

PubMed

Jordan, B R; Chow, W S; Strid, A; Anderson, J M

1991-06-17

The cab and psb A RNA transcript levels have been determined in Pisum sativum leaves exposed to supplementary ultraviolet-B radiation. The nuclear-encoded cab transcripts are reduced to low levels after only 4 h of UV-B treatment and are undetectable after 3 days exposure. In contrast, the chloroplast-encoded psb A transcript levels, although reduced, are present for at least 3 days. After short periods of UV-B exposure (4 h or 8 h), followed by recovery under control conditions, cab RNA transcript levels had not recovered after 1 day, but were re-established to ca. 60% of control levels after 2 more days. Increased irradiance during exposure to UV-B reduced the effect upon cab transcripts, although the decrease was still substantial. These results indicate rapid changes in the cellular regulation of gene expression in response to supplementary UV-B and suggest increased UV-B radiation may have profound consequences for future productivity of sensitive crop species.

Vertical redistribution of zooplankton in an oligotrophic lake associated with reduction in ultraviolet radiation by wildfire smoke

NASA Astrophysics Data System (ADS)

Urmy, Samuel S.; Williamson, Craig E.; Leach, Taylor H.; Schladow, S. Geoffrey; Overholt, Erin P.; Warren, Joseph D.

2016-04-01

We used a natural experiment to test whether wildfire smoke induced changes in the vertical distribution of zooplankton in Lake Tahoe by decreasing incident ultraviolet radiation (UV). Fires have a variety of effects on aquatic ecosystems, but these impacts are poorly understood and have rarely been observed directly. UV is an important driver of zooplankton vertical migration, and wildfires may alter it over large spatial scales. We measured UV irradiance and the distribution of zooplankton on two successive days. On one day, smoke haze from a nearby wildfire reduced incident UV radiation by up to 9%, but not irradiance in the visible spectrum. Zooplankton responded by positioning themselves, on average, 4.1 m shallower in the lake. While a limited data set such as this requires cautious interpretation, our results suggest that smoke from wildfires can change the UV environment and distribution of zooplankton. This process may be important in drought-prone regions with increasingly frequent wildfires, and globally due to widespread biomass burning.

Attempts to probe the ozone layer and the ultraviolet-B levels of the past.

PubMed

Björn, Lars Olof; McKenzie, Richard L

2007-07-01

To get a proper perspective on the current status of atmospheric ozone, which protects the biosphere from ultraviolet-B (UV-B; 280-315 nm) radiation, it would be of value to know how ozone and UV-B radiation have varied in the past. The record of worldwide ozone monitoring goes back only a few decades, and the record of reliable UV-B measurements is even shorter. Here we review indirect methods to assess their status further back in time. These include variations in the Sun's emission and how these affect the atmosphere, changes in the Earth's orbit, geologic imprints of atmospheric ozone, effects of catastrophic events such as volcanic eruptions, biological proxies of UV-B radiation, the spectral signature of terrestrial ozone in old recordings of star spectra, and the modeling of UV-B irradiance from ozone data and meteorological recordings. Although reliable reconstructions do not yet extend far into the past, there is some hope for future progress.

SR-71 Ship #1 - Ultraviolet Experiment

NASA Technical Reports Server (NTRS)

1994-01-01

NASA's SR-71 streaks into the twilight on a night/science flight from the Dryden Flight Research Center, Edwards, California. Mounted in the nose of the SR-71 was an ultraviolet video camera aimed skyward to capture images of stars, asteroids and comets. The science portion of the flight is a project of the Jet Propulsion Laboratory, Pasadena, California. Two SR-71 aircraft have been used by NASA as test beds for high-speed and high-altitude aeronautical research. One early research project flown on one of Dryden's SR-71s consisted of a proposal for a series of flights using the SR-71 as a science camera platform for the Jet Propulsion Laboratory (JPL) of the California Institute of Technology, which operates under contract to NASA in much the way that NASA centers do. In March 1993, an upward-looking ultraviolet (UV) video camera placed in the SR-71's nosebay studied a variety of celestial objects in the ultraviolet light spectrum. The SR-71 was proposed as a test bed for the experiment because it is capable of flying at altitudes above 80,000 feet for an extended length of time. Observation of ultraviolet radiation is not possible from the Earth's surface because the atmosphere's ozone layer absorbs UV rays. Study of UV radiation is important because it is known to cause skin cancer with prolonged exposure. UV radiation is also valuable to study from an astronomical perspective. Satellite study of ultraviolet radiation is very expensive. As a result, the South West Research Institute (SWRI) in Texas developed the hypothesis of using a high-flying aircraft such as the SR-71 to conduct UV observations. The SR-71 is capable of flying above 90 percent of the Earth's atmosphere. The flight program was also designed to test the stability of the aircraft as a test bed for UV observation. A joint flight program was developed between the JPL and NASA's Ames-Dryden Flight Research Facility (redesignated the Dryden Flight Research Center, Edwards, California, in 1994) in conjunction with SWRI to test the hypothesis. Dryden modified the nosebay of the SR-71, creating an upward-observing window to carry SWRI's ultraviolet CCD camera so it could make observations. According to Dryden's SR-71 Project Manager Dave Lux, a single flight of the aircraft confirmed the aircraft's capability and stability as a test bed for UV observations. SWRI's principle investigator was Dr. Allen Stern.

[Ultraviolet radiation-induced apoptosis in human lens epithelial cells and its effect on Bcl-2 and Bax].

PubMed

Jia, Songbai; Shi, Jingming; Chen, Xuan; Tang, Luosheng

2012-07-01

To explore the apoptosis-inducing effect of ultraviolet(UV) radiation on human lens epithelial cells (HLEC), with particular focus on changes in Bcl-2 or Bax expression as possible mechanisms. All experimental groups were exposed to the same UV light source. HLEC were divided into 6 groups according to duration of UV radiation : 0 min group (control group), 5 min group, 10 min group,15 min group, and 30 min group. Analysis on apoptosis of HLEC was performed by flow cytometry analysis (FCA, Annexin V + PI staining). Changes of Bax and Bcl-2 expression in HLEC were detected by hybridization in situ. Apoptosis in HLEC increased with UV exposure time. The expression level of Bax mRNA was increased with the increase of UV exposure time, whereas the expression level of Bcl-2 mRNA decreased with the increase of UV exposure time. The proportion of apoptotic cells was negatively correlated with ratio of Bcl-2/Bax (r=-0.874, P<0.05). UA radiation can induce apoptosis of HLEC in vitro. Bcl-2 and Bax genes may play an important role in regulating this apoptotic process.

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.

Transcriptomic Analysis of Grape (Vitis vinifera L.) Leaves after Exposure to Ultraviolet C Irradiation

PubMed Central

Xi, Huifen; Ma, Ling; Liu, Guotian; Wang, Nian; Wang, Junfang; Wang, Lina; Dai, Zhanwu; Li, Shaohua; Wang, Lijun

2014-01-01

Background Only a small amount of solar ultraviolet C (UV-C) radiation reaches the Earth's surface. This is because of the filtering effects of the stratospheric ozone layer. Artificial UV-C irradiation is used on leaves and fruits to stimulate different biological processes in plants. Grapes are a major fruit crop and are grown in many parts of the world. Research has shown that UV-C irradiation induces the biosynthesis of phenols in grape leaves. However, few studies have analyzed the overall changes in gene expression in grape leaves exposed to UV-C. Methodology/Principal Findings In the present study, transcriptional responses were investigated in grape (Vitis vinifera L.) leaves before and after exposure to UV-C irradiation (6 W·m−2 for 10 min) using an Affymetrix Vitis vinifera (Grape) Genome Array (15,700 transcripts). A total of 5274 differentially expressed probe sets were defined, including 3564 (67.58%) probe sets that appeared at both 6 and 12 h after exposure to UV-C irradiation but not before exposure. A total of 468 (8.87%) probe sets and 1242 (23.55%) probe sets were specifically expressed at these times. The probe sets were associated with a large number of important traits and biological pathways, including cell rescue (i.e., antioxidant enzymes), protein fate (i.e., HSPs), primary and secondary metabolism, and transcription factors. Interestingly, some of the genes involved in secondary metabolism, such as stilbene synthase, responded intensely to irradiation. Some of the MYB and WRKY family transcription factors, such as VvMYBPA1, VvMYB14, VvMYB4, WRKY57-like, and WRKY 65, were also strongly up-regulated (about 100 to 200 fold). Conclusions UV-C irridiation has an important role in some biology processes, especially cell rescue, protein fate, secondary metabolism, and regulation of transcription.These results opened up ways of exploring the molecular mechanisms underlying the effects of UV-C irradiation on grape leaves and have great implications for further studies. PMID:25464056

Transcriptomic analysis of grape (Vitis vinifera L.) leaves after exposure to ultraviolet C irradiation.

PubMed

Xi, Huifen; Ma, Ling; Liu, Guotian; Wang, Nian; Wang, Junfang; Wang, Lina; Dai, Zhanwu; Li, Shaohua; Wang, Lijun

2014-01-01

Only a small amount of solar ultraviolet C (UV-C) radiation reaches the Earth's surface. This is because of the filtering effects of the stratospheric ozone layer. Artificial UV-C irradiation is used on leaves and fruits to stimulate different biological processes in plants. Grapes are a major fruit crop and are grown in many parts of the world. Research has shown that UV-C irradiation induces the biosynthesis of phenols in grape leaves. However, few studies have analyzed the overall changes in gene expression in grape leaves exposed to UV-C. In the present study, transcriptional responses were investigated in grape (Vitis vinifera L.) leaves before and after exposure to UV-C irradiation (6 W·m-2 for 10 min) using an Affymetrix Vitis vinifera (Grape) Genome Array (15,700 transcripts). A total of 5274 differentially expressed probe sets were defined, including 3564 (67.58%) probe sets that appeared at both 6 and 12 h after exposure to UV-C irradiation but not before exposure. A total of 468 (8.87%) probe sets and 1242 (23.55%) probe sets were specifically expressed at these times. The probe sets were associated with a large number of important traits and biological pathways, including cell rescue (i.e., antioxidant enzymes), protein fate (i.e., HSPs), primary and secondary metabolism, and transcription factors. Interestingly, some of the genes involved in secondary metabolism, such as stilbene synthase, responded intensely to irradiation. Some of the MYB and WRKY family transcription factors, such as VvMYBPA1, VvMYB14, VvMYB4, WRKY57-like, and WRKY 65, were also strongly up-regulated (about 100 to 200 fold). UV-C irridiation has an important role in some biology processes, especially cell rescue, protein fate, secondary metabolism, and regulation of transcription.These results opened up ways of exploring the molecular mechanisms underlying the effects of UV-C irradiation on grape leaves and have great implications for further studies.

Modelling a man-portable air-defence (MANPAD) system with a rosette scan two-colour infrared (IR) and ultraviolet (UV) seeker

NASA Astrophysics Data System (ADS)

Kumar, Devinder; Smith, Leon; Richardson, Mark A.; Ayling, Richard; Barlow, Nick

2014-10-01

The Ultraviolet (UV) band of the electromagnetic (EM) spectrum has the potential to be used as the host medium for the operation of guided weapons. Unlike in the Infrared (IR), a target propelled by an air breathing jet engine produces no detectable radiation in the UV band, and is opaque to the background UV produced by the Sun. Successful engineering of spectral airborne IR countermeasures (CM) against existing two colour IR seekers has encouraged missile counter-countermeasure (CCM) designers to utilise the silhouette signature of an aircraft in the UV as a means of distinguishing between a true target and a flare CM. In this paper we describe the modelling process of a dual band IR and UV rosette scan seeker using CounterSim, a missile engagement and countermeasure simulation software package developed by Chemring Countermeasures Ltd. Results are shown from various simulated engagements of the dual band MANPAD with a C-130 Hercules modelled by Chemring Countermeasures. These results have been used to estimate the aircrafts' vulnerability to this MANPAD threat. A discussion on possible future optical countermeasures against dual band IR-UV seekers is given in conclusion to the simulation results.

Heme oxygenase up-regulation under ultraviolet-B radiation is not epigenetically restricted and involves specific stress-related transcriptions factors.

PubMed

Santa-Cruz, Diego; Pacienza, Natalia; Zilli, Carla; Pagano, Eduardo; Balestrasse, Karina; Yannarelli, Gustavo

2017-08-01

Heme oxygenase-1 (HO-1) plays a protective role against oxidative stress in plants. The mechanisms regulating its expression, however, remain unclear. Here we studied the methylation state of a GC rich HO-1 promoter region and the expression of several stress-related transcription factors (TFs) in soybean plants subjected to ultraviolet-B (UV-B) radiation. Genomic DNA and total RNA were isolated from leaves of plants irradiated with 7.5 and 15kJm-2 UV-B. A 304bp HO-1 promoter region was amplified by PCR from sodium bisulfite-treated DNA, cloned into pGEMT plasmid vector and evaluated by DNA sequencing. Bisulfite sequencing analysis showed similar HO-1 promoter methylation levels in control and UV-B-treated plants (C: 3.4±1.3%; 7.5: 2.6±0.5%; 15: 3.1±1.1%). Interestingly, HO-1 promoter was strongly unmethylated in control plants. Quantitative RT-PCR analysis of TFs showed that GmMYB177, GmMYBJ6, GmWRKY21, GmNAC11, GmNAC20 and GmGT2A but not GmWRK13 and GmDREB were induced by UV-B radiation. The expression of several TFs was also enhanced by hemin, a potent and specific HO inducer, inferring that they may mediate HO-1 up-regulation. These results suggest that soybean HO-1 gene expression is not epigenetically regulated. Moreover, the low level of HO-1 promoter methylation suggests that this antioxidant enzyme can rapidly respond to environmental stress. Finally, this study has identified some stress-related TFs involved in HO-1 up-regulation under UV-B radiation. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Interactions between the impacts of ultraviolet radiation, elevated CO2, and nutrient limitation on marine primary producers.

PubMed

Beardall, John; Sobrino, Cristina; Stojkovic, Slobodanka

2009-09-01

It is well known that UV radiation can cause deleterious effects to the physiological performance, growth and species assemblages of marine primary producers. In this review we describe the range of interactions observed between these impacts of ultraviolet radiation (UVR, 280-400 nm) with other environmental factors such as the availability of photosynthetically active radiation (PAR), nutrient status and levels of dissolved CO2, all of which can, in turn, be influenced by global climate change. Thus, increases in CO2 levels can affect the sensitivity of some species to UV-B radiation (UV-B), while others show no such impact on UV-B susceptibility. Both nitrogen- and phosphorus-limitation can have direct interactive effects on the susceptibility of algal cells and communities to UVR, though such effects are somewhat variable. Nutrient depletion can also potentially lead to a dominance of smaller celled species, which may be less able to screen out and are thus likely to be more susceptible to UVR-induced damage. The variability of responses to such interactions can lead to alterations in the species composition of algal assemblages.

Enhancement of pectinase production by ultraviolet irradiation and diethyl sulfate mutagenesis of a Fusarium oxysporum isolate.

PubMed

Yin, L B; Zhang, C F; Xia, Q L; Yang, Y; Xiao, K; Zhao, L Z

2016-09-23

Fusarium oxysporum strain BM-201 was treated with ultraviolet (UV) radiation to obtain a high pectinase-producing strain. Mutant UV-10-41 was obtained and then treated by diethyl sulfate. Next, the mutant UV-diethyl sulfate-43 derived from UV-10-41 was selected as high pectinase-producing strain. Mutant UV-diethyl sulfate-43 was incubated on slant for 10 generations, demonstrating that the pectinase-producing genes were stable. Pectinase activity reached 391.2 U/mL, which is 73.6% higher than that of the original strain.

EXPERIMENTS - APOLLO 17

NASA Image and Video Library

1972-11-17

S72-53470 (November 1972) --- The Far-Ultraviolet Spectrometer, Experiment S-169, one of the lunar orbital science experiments which will be mounted in the SIM bay of the Apollo 17 Service Module. Controls for activating and deactivating the experiment and for opening and closing a protective cover are located in the Command Module. Atomic composition, density and scale height for several constituents of the lunar atmosphere will be measured by the far-ultraviolet spectrometer. Solar far-UV radiation reflected from the lunar surface as well as UV radiation emitted by galactic sources also will be detected by the instrument.

Vulnerability and behavioral response to ultraviolet radiation in the components of a foliar mite prey-predator system.

PubMed

Tachi, Fuyuki; Osakabe, Masahiro

2012-12-01

Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey-predator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose-response (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites (Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite (Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species (T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition.

Vulnerability and behavioral response to ultraviolet radiation in the components of a foliar mite prey-predator system

NASA Astrophysics Data System (ADS)

Tachi, Fuyuki; Osakabe, Masahiro

2012-12-01

Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey-predator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose-response (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites ( Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite ( Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species ( T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition.

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.

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

Synergistic effects of sodium hypochlorite and ultraviolet radiation in reducing the levels of selected foodborne pathogenic bacteria.

PubMed

Ha, Ji-Hyoung; Ha, Sang-Do

2011-05-01

The purpose of this study was to determine whether combined treatment would produce synergistic effects to facilitate the sterilization of food products during production relative to single treatment. To assess this hypothesis, we investigated the bactericidal effects of ultraviolet (UV) irradiation and a commercial chemical disinfectant, sodium hypochlorite (NaClO), on Bacillus cereus F4810/72, Cronobacter sakazakii KCTC 2949, Staphylococcus aureus ATCC 35556, Escherichia coli ATCC 10536, and Salmonella Typhimurium novobiocin/nalidixic acid in vitro. Various concentrations of NaClO (20, 60, 100, and 200 ppm NaClO) were tested along with exposure to UV radiation at various doses (6, 96, 216, 360, and 504 mW s/cm(2)). The combined NaClO/UV treatments resulted in greater reductions in bacterial counts than either treatment alone. The synergy values against B. cereus, C. sakazakii, S. aureus, Salmonella Typhimurium, and E. coli were 0.25-1.17, 0.33-1.97, 0.42-1.72, 0.02-1.44, and 0.01-0.85 log(10) CFU/mL, respectively. The results of this study suggest that a significant synergistic benefit results from combined NaClO/UV processing against food-borne pathogenic bacteria in vitro.

Resistance of the Extreme Halophile Halobacterium sp. NRC-1 to Multiple Stresses

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

Gygli, Patrick E.; Prajapati, Surendra; DeVeaux, Linda C.

2009-03-10

The model Archaeon Halobacterium sp. NRC-1 is an extreme halophile known for its resistance to multiple stressors, including electron-beam and ultraviolet radiation. It is a well-developed system with a completely sequenced genome and extensive post-genomic tools for the study of a variety of biological processes. To further understand the mechanisms of Halobacterium's, radiation resistance, we previously reported the selection for multiple independent highly resistant mutants using repeated exposure to high doses of 18-20 MeV electrons using a medical S-band Linac. Molecular analysis of the transcriptional profile of several of these mutants revealed a single common change: upregulation of the rfa3more » operon. These genes encode proteins homologous to the subunits of eukaryotic Replication Protein A (RPA), a DNA binding protein with major roles in DNA replication, recombination, and repair. This operon has also been implicated in a somewhat lesser role in resistance of wild type Halobacterium to ultraviolet radiation, suggesting common mechanisms for resistance. To further understand the mechanism of radiation resistance in the mutant strains, we measured the survival after exposure to both electron-beam and ultraviolet radiation, UV-A, B, and C All mutant strains showed increased resistance to electrons when compared with the parent. However, the mutant strains do not display increased UV resistance, and in one case is more sensitive than the parent strain. Thus, the protective role of increased RPA expression within a cell may be specific to the DNA damage caused by the different physical effects induced by high energy electron-beam radiation.« less

Interpreting the Ultraviolet Aerosol Index Observed with the OMI Satellite Instrument to Understand Absorption by Organic Aerosols: Implications for Atmospheric Oxidation and Direct Radiative Effects

NASA Technical Reports Server (NTRS)

Hammer, Melanie S.; Martin, Randall V.; Donkelaar, Aaron van; Buchard, Virginie; Torres, Omar; Ridley, David A.; Spurr, Robert J. D.

2016-01-01

Satellite observations of the ultraviolet aerosol index (UVAI) are sensitive to absorption of solar radiation by aerosols; this absorption affects photolysis frequencies and radiative forcing. We develop a global simulation of the UVAI using the 3-D chemical transport model GEOSChem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT). The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI) for the year 2007. Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (-0.32 to -0.97) exists between simulated and observed values in biomass burning regions. We determine effective optical properties for absorbing organic aerosol, known as brown carbon (BrC), and implement them into GEOS-Chem to better represent observed UVAI values over biomass burning regions. The inclusion of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from -0.57 to -0.09 over West Africa in January, from -0.32 to +0.0002 over South Asia in April, from -0.97 to -0.22 over southern Africa in July, and from -0.50 to +0.33 over South America in September. The spectral dependence of absorption after including BrC in the model is broadly consistent with reported observations for biomass burning aerosol, with absorbing Angstrom exponent (AAE) values ranging from 2.9 in the ultraviolet (UV) to 1.3 across the UV-Near IR spectrum. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining tropospheric hydroxyl radical (OH) concentrations in GEOS-Chem. The inclusion of BrC decreases OH by up to 30% over South America in September, up to 20% over southern Africa in July, and up to 15% over other biomass burning regions. Global annual mean OH concentrations in GEOS-Chem decrease due to the presence of absorbing BrC, increasing the methyl chloroform lifetime from 5.62 to 5.68 years, thus reducing the bias against observed values. We calculate the direct radiative effect (DRE) of BrC using GEOS-Chem coupled with the radiative transfer model RRTMG (GC-RT). Treating organic aerosol as containing more strongly absorbing BrC changes the global annual mean all-sky top of atmosphere (TOA) DRE by +0.03Wm(exp -2) and all-sky surface DRE by -0.08Wm(exp -2). Regional changes of up to +0.3Wm(exp -2) at TOA and down to -1.5Wm(exp -2) at the surface are found over major biomass burning regions.

Photochemically induced carbon dioxide production as a mechanism for carbon loss from plant litter in arid ecosystems

NASA Astrophysics Data System (ADS)

Brandt, L. A.; Bohnet, C.; King, J. Y.

2009-06-01

We investigated the potential for abiotic mineralization to carbon dioxide (CO2) via photodegradation to account for carbon (C) loss from plant litter under conditions typical of arid ecosystems. We exposed five species of grass and oak litter collected from arid and mesic sites to a factorial design of ultraviolet (UV) radiation (UV pass, UV block), and sterilization under dry conditions in the laboratory. UV pass treatments produced 10 times the amount of CO2 produced in UV block treatments. CO2 production rates were unaffected by litter chemistry or sterilization. We also exposed litter to natural solar radiation outdoors on clear, sunny days close to the summer solstice at midlatitudes and found that UV radiation (280-400 nm) accounted for 55% of photochemically induced CO2 production, while shortwave visible radiation (400-500 nm) accounted for 45% of CO2 production. Rates of photochemically induced CO2 production on a per-unit-mass basis decreased with litter density, indicating that rates depend on litter surface area. We found no evidence for leaching, methane production, or facilitation of microbial decomposition as alternative mechanisms for significant photochemically induced C loss from litter. We conclude that abiotic mineralization to CO2 is the primary mechanism by which C is lost from litter during photodegradation. We estimate that CO2 production via photodegradation could be between 1 and 4 g C m-2 a-1 in arid ecosystems in the southwestern United States. Taken together with low levels of litter production in arid systems, photochemical mineralization to CO2 could account for a significant proportion of annual carbon loss from litter in arid ecosystems.

Cyclosporin A inhibits UV-radiation-induced membrane damage but is unable to inhibit carboxyatractyloside-induced permeability transition.

PubMed

García, Noemí; Zazueta, Cecilia; El-Hafidi, Mohammed; Pavón, Natalia; Martínez-Abundis, Eduardo; Hernández-Esquivel, Luz; Chávez, Edmundo

2009-11-01

This work was undertaken to gain further information on the chemical characteristics of the membrane entity involved in the formation of the nonspecific pore. Mitochondria were subjected to oxidative stress by exposure to UV radiation. The results indicate that ultraviolet C radiation induces structural modifications in the adenine nucleotide translocase that lead to membrane permeability transition. Membrane leakage was assessed by measuring mitochondrial Ca2+ transport, the transmembrane electric gradient, and mitochondrial swelling. UV-irradiated mitochondria were unable to retain matrix Ca2+ or to maintain a high level of membrane potential when Ca2+ was added; furthermore, UV-irradiated mitochondria underwent large amplitude swelling. Release of cytochrome c and formation of malondialdehyde, owing to lipid peroxidation, were also seen. Structural modifications of the translocase were revealed by an increase in the binding of the fluorescent probe eosin-5-maleimide to thiol residues of the ADP/ATP carrier. These modifications, taken together with findings indicating that cyclosporin resulted unable to inhibit carboxyatractyloside-induced permeability transition, prompted us to conclude that the translocase could constitute the nonspecific pore or at least be an important modulator of it.

Ultraviolet-C light inactivation of Penicillium expansum on fruit surfaces

USDA-ARS?s Scientific Manuscript database

Understanding the influence of fruit surface morphology on ultraviolet-C (UV-C 254 nm) inactivation of microorganisms is required for designing effective treatment systems. In this study, we analyzed UV-C inactivation of Penicillium expansum that was inoculated onto the surface of organic fruits. Re...

ESTIMATION OF UV-B EXPOSURE IN AMPHIBIAN AQUATIC ENVIRONMENTS

EPA Science Inventory

Estimation of ultraviolet radiation B (UV-B; 280 to 320 nm wavelenghts) dose is essential for determining whether UV-B contributes to amphibian population declines and malformations. UV-B dose in wetlands is effected by location, time of day and year, atmospheric levels of ozone,...

Lighting considerations in controlled environments for nonphotosynthetic plant responses to blue and ultraviolet radiation

NASA Technical Reports Server (NTRS)

Caldwell, M. M.; Flint, S. D.

1994-01-01

This essay will consider both physical and photobiological aspects of controlled environment lighting in the spectral region beginning in the blue and taken to the normal limit of the solar spectrum in the ultraviolet. The primary emphasis is directed to questions of plant response to sunlight. Measurement and computations used in radiation dosimetry in this part of the spectrum are also briefly treated. Because of interest in the ozone depletion problem, there has been some activity in plant UV-B research and there are several recent reviews available. Some aspects of growth chamber lighting as it relates to UV-B research were covered earlier. Apart from work related to the blue/UV-A receptor, less attention has been given to UV-A responses.

Lighting considerations in controlled environments for nonphotosynthetic plant responses to blue and ultraviolet radiation

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

Caldwell, M.M.; Flint, S.D.

1994-12-31

This essay will consider both physical and photobiological aspects of controlled environment lighting in the spectral region beginning in the blue and taken to the normal limit of the solar spectrum in the ultraviolet. The primary emphasis is directed to questions of plant response to sunlight. Measurement and computations used in radiation dosimetry in this part of the spectrum are also briefly treated. Because of interest in the ozone depletion problem, there has been some activity in plant UV-B research and there are several recent reviews available. Some aspects of growth chamber lighting as it relates to UV-B research weremore » covered earlier. Apart from work related to the blue/UV-A receptor, less attention has been given to UV-A responses.« less

The flavonoid, fisetin, inhibits UV radiation-induced oxidative stress and the activation of NF-kappaB and MAPK signaling in human lens epithelial cells.

PubMed

Yao, Ke; Zhang, Li; Zhang, Yidong; Ye, PanPan; Zhu, Ning

2008-01-01

Ultraviolet (UV) radiation-induced oxidative stress plays a significant role in the progression of cataracts. This study investigated the photoprotective effect of fisetin on UV radiation-induced oxidative stress in human lens epithelial cells and the possible molecular mechanism involved. SRA01/04 cells exposed to different doses of ultraviolet B (UVB) were cultured with various concentrations of fisetin and subsequently monitored for cell viability by the 4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay. The effect of fisetin on the generation of reactive oxygen species (ROS) of SRA01/04 cells was determined by flow cytometry. Translocation of nuclear factor kappa-B (NF-kappaB) was examined by immunocytochemistry. Expression of NF-kappaB/P65, inhibiter kappa B (IkappaB), and mitogen activated protein kinase (MAPK) proteins were measured by western blot. Treatment of SRA01/04 cells with fisetin inhibited UVB-induced cell death and the generation of ROS. Fisetin inhibited UVB-induced activation and translocation of NF-kappaB/p65, which was mediated through an inhibition of the degradation and activation of IkappaB. Fisetin also inhibited UVB-induced phosphorylation of the p38 and c-Jun N-terminal kinase (JNK) proteins of the MAPK family at various time points studied. The flavonoid, fisetin, could be useful in attenuation of UV radiation-induced oxidative stress and the activation of NF-kappaB and MAPK signaling in human lens epithelial cells, which suggests that fisetin has a potential protective effect against cataractogenesis.

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...

SUPPLEMENTAL ULTRAVIOLET-B RADIATION DOES NOT REDUCE GROWTH OR GRAIN YIELD IN RICE

EPA Science Inventory

Negative effects of enhanced UV-B radiation have been demonstrated in plants, but impacts under realistic field conditions remain uncertain. Adverse impacts to major crops, such as rice (Oryza sativa L.), that are grown in areas with currently high ambient levels of UV-B, could h...

Production of Chromophoric Dissolved Organic Matter from Mangrove Leaf Litter and Floating Sargassum Colonies

EPA Science Inventory

Chromophoric dissolved organic matter (CDOM) strongly absorbs solar radiation in the blue-green and serves as the primary attenuator of water column ultraviolet radiation (UV-R). CDOM interferes with remote sensing of ocean chlorophyll and can control UV-R-induced damage to light...

Plant Phenolics as Radiation Protectants For The Beet Armyworm (Lepidoptera: Noctuidae) Nucleopolyhedrovirus

USDA-ARS?s Scientific Manuscript database

Thirteen phenolics were tested as ultraviolet (UV) protectants for the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner). After 30 minute exposure to UVB/UVB radiation, eleven SeMNPV/phenolic combinations provided good to excellent UV protection when used at a concentra...

[Light protection for xeroderma pigmentosum].

PubMed

Ettinger, M; Berneburg, M

2017-05-01

Xeroderma pigmentosum is a rare autosomal recessive disorder which is caused by germinal mutations responsible for the repair of ultraviolet (UV) radiation-induced DNA lesions. It is characterized by hypersensitivity to UV radiation, poikiloderma, ocular surface disease, and in some patients pronounced sunburn and neurological disease. Patients have a very high risk of developing ocular and skin cancer on exposed body sites. No cure is available for these patients except complete protection from all types of UV radiation.

Dual Band Deep Ultraviolet AlGaN Photodetectors

NASA Technical Reports Server (NTRS)

Aslam, S.; Miko, L.; Stahle, C.; Franz, D.; Pugel, D.; Guan, B.; Zhang, J. P.; Gaska, R.

2007-01-01

We report on the design, fabrication and characterization of a back-illuminated voltage bias selectable dual-band AlGaN UV photodetector. The photodetector can separate UVA and W-B band radiation by bias switching a two terminal n-p-n homojunction structure that is fabricated in the same pixel. When a forward bias is applied between the top and bottom electrodes, the detector can sense UV-A and reject W-B band radiation. Alternatively, under reverse bias, the photodetector can sense UV-B and reject UV-A band radiation.

Modeling TiO2 nanoparticle phototoxicity: The importance of chemical concentration, ultraviolet radiation intensity, and time

EPA Science Inventory

Toxicity of TiO2 nanoparticles (nano-TiO2) to aquatic organisms can be greatly increased upon the exposure to ultraviolet radiation (UV). This phenomenon has received some attention for pelagic species, however, investigations of nano-TiO2 phototoxicity in benthic organisms are s...

Experimental Determination of Ultraviolet Radiation Protection of Common Materials

ERIC Educational Resources Information Center

Tavares, Susana C. A.; da Silva, Joaquim C. G. Esteves; Paiva, Joao

2007-01-01

Aiming at a better understanding of the problems associated with the depletion of the ozone layer, we propose several experiments to be performed by students of different levels: secondary and first-year undergraduate students. The oxidation of iodide induced by ultraviolet (UV) radiation, generated by a mercury lamp, is used as an indicator for…

Impact of nanostructured thin ZnO film in ultraviolet protection

PubMed Central

Sasani Ghamsari, Morteza; Alamdari, Sanaz; Han, Wooje; Park, Hyung-Ho

2017-01-01

Nanoscale ZnO is one of the best choices for ultraviolet (UV) protection, not only because of its antimicrobial properties but also due to its potential application for UV preservation. However, the behavior of nanostructured thin ZnO films and long-term effects of UV-radiation exposure have not been studied yet. In this study, we investigated the UV-protection ability of sol gel-derived thin ZnO films after different exposure times. Scanning electron microscopy, atomic force microscopy, and UV-visible optical spectroscopy were carried out to study the structure and optical properties of the ZnO films as a function of the UV-irradiation time. The results obtained showed that the prepared thin ZnO films were somewhat transparent under the visible wavelength region and protective against UV radiation. The UV-protection factor was 50+ for the prepared samples, indicating that they were excellent UV protectors. The deposited thin ZnO films demonstrated promising antibacterial potential and significant light absorbance in the UV range. The experimental results suggest that the synthesized samples have potential for applications in the health care field. PMID:28096668

Impact of nanostructured thin ZnO film in ultraviolet protection.

PubMed

Sasani Ghamsari, Morteza; Alamdari, Sanaz; Han, Wooje; Park, Hyung-Ho

2017-01-01

Nanoscale ZnO is one of the best choices for ultraviolet (UV) protection, not only because of its antimicrobial properties but also due to its potential application for UV preservation. However, the behavior of nanostructured thin ZnO films and long-term effects of UV-radiation exposure have not been studied yet. In this study, we investigated the UV-protection ability of sol gel-derived thin ZnO films after different exposure times. Scanning electron microscopy, atomic force microscopy, and UV-visible optical spectroscopy were carried out to study the structure and optical properties of the ZnO films as a function of the UV-irradiation time. The results obtained showed that the prepared thin ZnO films were somewhat transparent under the visible wavelength region and protective against UV radiation. The UV-protection factor was 50+ for the prepared samples, indicating that they were excellent UV protectors. The deposited thin ZnO films demonstrated promising antibacterial potential and significant light absorbance in the UV range. The experimental results suggest that the synthesized samples have potential for applications in the health care field.

UV Filters and Toursim: Their Impact on the Environment

EPA Science Inventory

Ultraviolet (UV) filters are widely used in cosmetics, sunscreens, and plastics to block UV radiation from the sun. Studies show that some sunscreens demonstrate estrogenicity and multiple hormonal activities in vitro. Because of the high consumption volume and high lipophilicity...

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

Undeen, A.H.; Vander Meer, R.K.

Spores of Nosema algerae Vavra and Undeen were subjected to various dosages of 254 nm ultraviolet radiation (UV). Very high dosages of UV were required to block germination. Germination was normal immediately after UV dosages of 0.2 to 1.0 J/cm2, followed by a delayed effect in which both percentage germination and the intrasporal concentration of trehalose decreased with time after UV exposure. Although a few spores were germinated, most of them were inactivated (rendered temporarily unable to germinate) by exposure to UV of 1.1 J/cm2. Ultraviolet radiation between 1.1 and 3.4 J/cm2 stimulated spores to germinate. However, spores were completelymore » unable to germinate immediately after exposure to dosages above 3.8 J/cm2. Ammonia had little effect on stimulation by UV but was inhibitory to germination after stimulation had occurred. These results demonstrate that UV behaves like a germination stimulus and are discussed in terms of the hypothesis that germination is initiated by the breakdown of barriers between trehalose and trehalase.« less

Ultraviolet laser effects on the cornea

NASA Astrophysics Data System (ADS)

Zuclich, Joseph A.

1990-07-01

Ultraviolet radiation in the ambient environment or from artificial sources may pose both acute and chronic hazards to the skin and the ocular tissues. In general terrestrial conditions have evolved such that there are only narrow safety margins between ambient UV levels and exposure levels harmful to the human. Obvious examples of acute consequences ofUV overexposure are sunburn and snowblindness as well as analogous conditions induced by artificial sources such as the welder''s arc mercury vapor lamps and UV-emitting lasers. Further chronic UV exposure is strongly implicated as a causative agent in certain types of cataract and skin cancer. This presentation will summarize a number of specific cases where UV radiation affected the primate cornea. Data presented will include the action spectra for far- and near-UV induced ocular damage the pulsewidth and total energy dependencies of ocular thresholds studies of cumulative effects of repeated UV exposures and quantitative determinations of tissue repair or recovery rates. Depending on the exposure parameters utilized photochemical thermal or photoablative damage mechanisms may prevail. 1.

Medical Surveillance Monthly Report

DTIC Science & Technology

2016-12-01

sure to ultraviolet radiation is the major risk factor for NMSC, personal pro- tective measures such as wearing proper clothing, decreasing time in...tone and light-colored eyes and hair, and envi- ronmental factors, particularly exposure to solar ultraviolet (UV) radiation .4 In the U.S., the... radiation is well accepted as a risk factor as evidenced by observed patterns or the anatomic distributions of NMSCs, higher rates by latitude, higher

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...

Impacts of diurnal variation of ultraviolet-B and photosynthetically active radiation on phycobiliproteins of the hot-spring cyanobacterium Nostoc sp. strain HKAR-2.

PubMed

Kannaujiya, Vinod K; Sinha, Rajeshwar P

2017-01-01

The effects of diurnal variation of photosynthetically active radiation (PAR; 400-700 nm) and ultraviolet-B (UV-B; 280-315 nm) radiation on phycobiliproteins (PBPs) and photosynthetic pigments (PP) have been studied in the hot-spring cyanobacterium Nostoc sp. strain HKAR-2. The variations in PBPs and PP were monitored by alternating light and dark under PAR, UV-B, and PAR + UV-B radiations over a period of 25 h. There was a decline in the amount of Chl a and PBPs during light periods of UV-B and PAR + UV-B and an increase during dark periods showing a circadian rhythm by destruction and resynthesis of pigment-protein complex. However, a marked induction in carotenoids was recorded during light periods of the same radiations. Moreover, the ratio of Chl a/PE and Chl a/PC was increased in dark periods showing the resynthesis of bleached Chl a. The wavelength shift in emission fluorescence of PBPs toward shorter wavelengths further indicated the bleaching and destruction of PBPs during light periods. Oxidative damage upon exposure to PAR, UV-B, and PAR + UV-B was alleviated by induction of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The studied cyanobacterium exhibits a significant increase in the activities of SOD, CAT, and APX upon exposure to UV-B and PAR + UV-B radiations. The results indicate that pigment-protein composition of Nostoc sp. stain HKAR-2 was significantly altered during diurnal variation of light/radiation, which might play an important role in optimization for their productivity in a particular cyanobacterium.

Development of deep-ultraviolet metal vapor lasers

NASA Astrophysics Data System (ADS)

Sabotinov, Nikola V.

2004-06-01

Deep ultraviolet laser generation is of great interest in connection with both the development of new industrial technologies and applications in medicine, biology, chemistry, etc. The development of metal vapor UV lasers oscillating in the pulsed mode with high pulse repetition frequencies and producing high average output powers is of particular interest for microprocessing of polymers, photolithography and fluorescence applications. At present, metal vapor lasers generate deep-UV radiation on the base of two methods. The first method is non-linear conversion of powerful laser generation from the visible region into the deep ultraviolet region. The second method is direct UV laser action on ion and atomic transitions of different metals.

DETECTION OF INFECTIOUS ADENOVIRUS IN TERTIARY TREATED AND UV DISINFECTED WASTEWATER DURING A UV DISINFECTION PILOT STUDY

EPA Science Inventory

An infectious enteric adenovirus was isolated from urban wastewater receiving tertiary treatment and ultraviolet (UV) disinfection. A pilot study was undertaken to investigate the efficacy of UV disinfection (low pressure, high intensity radiation) of total and fecal coliform bac...

Ultraviolet radiation-induced cataract in mice: the effect of age and the potential biochemical mechanism.

PubMed

Zhang, Jie; Yan, Hong; Löfgren, Stefan; Tian, Xiaoli; Lou, Marjorie F

2012-10-19

To study the effect of age on the morphologic and biochemical alterations induced by in vivo exposure of ultraviolet radiation (UV). Young and old C57BL/6 mice were exposed to broadband UVB+UVA and euthanized after 2 days. Another batch of UV-exposed young mice was monitored for changes after 1, 2, 4, and 8 days. Age-matched nonexposed mice served as controls. Lens changes were documented in vivo by slit-lamp biomicroscopy and dark field microscopy photographs ex vivo. Lens homogenates were analyzed for glutathione (GSH) level, and the activities of thioredoxin (Trx), thioltransferase (TTase), and glyceraldehyde-3-phosphate dehydrogenase (G3PD). Glutathionylated lens proteins (PSSGs) were detected by immunoblotting using GSH antibody. Western blot analysis was also done for the expression levels of TTase and Trx. Both age groups developed epithelial and superficial anterior subcapsular cataract at 2 days postexposure. The lens GSH level and G3PD activity were decreased, and PSSGs were elevated in both age groups, but more prominent in the older mice. TTase and Trx activity and protein expression were elevated only in the young mice. Interestingly, lens TTase and Trx in the young mice showed a transient increase, peaking at 2 days after UV exposure and returning to baseline at day 8, corroborated by lens transparency. The lenses of old mice were more susceptible to UV radiation-induced cataract. The upregulated TTase and Trx likely provided oxidation damage repair in the young mice.

Sun and Sjogren's Syndrome

MedlinePlus

... California, for authoring this Patient Education Sheet. Ultraviolet (UV) radiation emitted from the sun and other light ... autoantibody SSA/or Ro. To avoid reactions to UV light, try the following tips: Protect your skin ...

Ultraviolet stress delays chromosome replication in light/dark synchronized cells of the marine cyanobacterium Prochlorococcus marinus PCC9511

PubMed Central

2010-01-01

Background The marine cyanobacterium Prochlorococcus is very abundant in warm, nutrient-poor oceanic areas. The upper mixed layer of oceans is populated by high light-adapted Prochlorococcus ecotypes, which despite their tiny genome (~1.7 Mb) seem to have developed efficient strategies to cope with stressful levels of photosynthetically active and ultraviolet (UV) radiation. At a molecular level, little is known yet about how such minimalist microorganisms manage to sustain high growth rates and avoid potentially detrimental, UV-induced mutations to their DNA. To address this question, we studied the cell cycle dynamics of P. marinus PCC9511 cells grown under high fluxes of visible light in the presence or absence of UV radiation. Near natural light-dark cycles of both light sources were obtained using a custom-designed illumination system (cyclostat). Expression patterns of key DNA synthesis and repair, cell division, and clock genes were analyzed in order to decipher molecular mechanisms of adaptation to UV radiation. Results The cell cycle of P. marinus PCC9511 was strongly synchronized by the day-night cycle. The most conspicuous response of cells to UV radiation was a delay in chromosome replication, with a peak of DNA synthesis shifted about 2 h into the dark period. This delay was seemingly linked to a strong downregulation of genes governing DNA replication (dnaA) and cell division (ftsZ, sepF), whereas most genes involved in DNA repair (such as recA, phrA, uvrA, ruvC, umuC) were already activated under high visible light and their expression levels were only slightly affected by additional UV exposure. Conclusions Prochlorococcus cells modified the timing of the S phase in response to UV exposure, therefore reducing the risk that mutations would occur during this particularly sensitive stage of the cell cycle. We identified several possible explanations for the observed timeshift. Among these, the sharp decrease in transcript levels of the dnaA gene, encoding the DNA replication initiator protein, is sufficient by itself to explain this response, since DNA synthesis starts only when the cellular concentration of DnaA reaches a critical threshold. However, the observed response likely results from a more complex combination of UV-altered biological processes. PMID:20670397

Sensitivity of two salamander (Ambystoma) species to ultraviolet radiation

USGS Publications Warehouse

Calfee, R.D.; Bridges, C.M.; Little, E.E.

2006-01-01

Increased ultraviolet-B (UV-B) radiation reaching the Earth's surface has been implicated in amphibian declines. Recent studies have shown that many amphibian species have differences in sensitivity depending on developmental stage. Embryos and larvae of Ambystoma maculatum (Spotted Salamander) and larvae of Ambystoma talpoideum (Mole Salamander) were exposed to five simulated UV-B treatments in controlled laboratory experiments to determine the relative sensitivity of different lifestages. Hatching success of the embryos exceeded 95% in all treatments; however, the larvae of both species exhibited greater sensitivity to UV-B exposure. Older larvae of A. maculatum that were not exposed to UV-B as embryos were more sensitive than larvae that had hatched during exposure to UV-B. Growth of surviving larvae of A. maculatum was significantly reduced as UV-B intensity increased, whereas growth of A. talpoideum was unaffected. These results were compared to ambient UV-B conditions in natural environments. It appears that the embryo stage is relatively unaffected by UV-B levels observed in natural habitats, probably because of protection from vegetation, organic matter in the water column, oviposition depth, and egg jelly. The larval stage of these species may be at greater risk, particularly if there is an increase in UV-B radiation exposure caused by increases in water clarity and/or decreases in dissolved organic carbon.

Differential toxicity of drinking water disinfected with combinations of ultraviolet radiation and chlorine.

PubMed

Plewa, Michael J; Wagner, Elizabeth D; Metz, Deborah H; Kashinkunti, Ramesh; Jamriska, Katherine J; Meyer, Maria

2012-07-17

Alternative technologies to disinfect drinking water such as ultraviolet (UV) disinfection are becoming more widespread. The benefits of UV disinfection include reduced risk of microbial pathogens such as Cryptosporidium and reduced production of regulated drinking water disinfection byproducts (DBPs). The objective of this research was to determine if mammalian cell cytotoxicity and genotoxicity varied in response to different chlorination protocols with and without polychromatic medium pressure UV (MPUV) and monochromatic low pressure UV (LPUV) disinfection technologies. The specific aims were to analyze the mammalian cell cytotoxicity and genotoxicity of concentrated organic fractions from source water before and after chlorination and to determine the cytotoxicity and genotoxicity of the concentrated organic fractions from water samples treated with UV alone or UV before or after chlorination. Exposure of granular activated carbon-filtered Ohio River water to UV alone resulted in the lowest levels of mammalian cell cytotoxicity and genotoxicity. With combinations of UV and chlorine, the lowest levels of cytotoxicity and genotoxicity were observed with MPUV radiation. The best combined UV plus chlorine methodology that generated the lowest cytotoxicity and genotoxicity employed chlorination first followed by MPUV radiation. These data may prove important in the development of multibarrier methods of pathogen inactivation of drinking water, while limiting unintended toxic consequences.

Protection of Nomex from Ultraviolet Degradation

DTIC Science & Technology

1977-03-01

absorbs UV radiation beginning at approximately 390 nano- meters (nm) and extending into the near UV with a peak at approximately 360 nm. This absorption is...the region near 290 nm [ 5 ]. Sunlight is much richer in radiation at 360 nm than at 290 nm and this fact undoubt- edly accounts for the much greater...function as UV screening agents. The absorption spectrum of Nomex in the near UV and visible region which is responsible for Nomex photodegra- dation is

Combined effects of lanthanum(III) and elevated ultraviolet-B radiation on root growth and ion absorption in soybean seedlings.

PubMed

Huang, Guang Rong; Wang, Li Hong; Zhou, Qing

2014-03-01

Rare earth element accumulation in the soil and elevated ultraviolet (UV)-B radiation (280-315 nm) are important environmental issues worldwide. To date, there have been no reports concerning the combined effects of lanthanum (La)(III) and elevated UV-B radiation on plant roots in regions where the two issues occur simultaneously. Here, the combined effects of La(III) and elevated UV-B radiation on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean (Glycine max L.) seedlings were investigated. A 0.08 mmol L(-1) La(III) treatment improved the root growth and biomass of soybean seedlings, while ion absorption, activities, and membrane permeability were obviously unchanged; a combined treatment with 0.08 mmol L(-1) La(III) and elevated UV-B radiation (2.63/6.17 kJ m(-2) day(-1)) exerted deleterious effects on the investigated indices. The deleterious effects were aggravated in the other combined treatments and were stronger than those of treatments with La(III) or elevated UV-B radiation alone. The combined treatment with 0.24/1.20 mmol L(-1) La(III) and elevated UV-B radiation exerted synergistically deleterious effects on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean seedlings. In addition, the deleterious effects of the combined treatment on the root growth were due to the inhibition of ion absorption induced by the changes in the root activity and membrane permeability.

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 any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

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 any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

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.

Ultraviolet A irradiation of the eye activates a nitric oxide-dependent hypothalamo-pituitary pro-opiomelanocortin pathway and modulates the functions of Langerhans cells.

PubMed

Hiramoto, Keiichi

2009-06-01

Ultraviolet A (UV-A) radiation decreases Langerhans cells (LC) in the skin specifically at the site of exposure. Unexpectedly, UV-A irradiation of the eye has been found systemically downregulating epidermal LC in mice. Male C57BL/6j mice and an inducible type of nitric oxide synthase knockout mice (iNOS(-/-)) were used in this study. The eye or ear was locally exposed to UV-A after covering the remaining body surface with aluminum foil at a dose of 110 kJ/m(2) using a sunlamp. Localized UV-A irradiation of the eye downregulated epidermal LC. The hypophysectomy strongly inhibited the UV-A-induced downregulation of LC. To elucidate the pathway by UV-A irradiation of the eye, the effect of a bilateral ciliary ganglionectomy and denervation of the optic nerves was examined. Optic nerve denervation strongly inhibited LC downregulation in response to localized irradiation of the eye. Furthermore, no LC downregulation in response to localized UV-A irradiation of the eye was observed in iNOS(-/-) mice. These results clearly indicate that a signal evoked by UV-A irradiation of the eye is transmitted in a nitric oxide-dependent manner through the optic nerves to the hypothalamo-pituitary pro-opiomelanocortin system.

Inactivation of carotenoid-producing and albino strains of Neurospora crassa by visible light, blacklight, and ultraviolet radiation.

PubMed Central

Blanc, P L; Tuveson, R W; Sargent, M L

1976-01-01

Suspensions of Neurospora crassa conidia were inactivated by blacklight (BL) radiation (300 to 425 nm) in the absence of exogenous photosensitizing compounds. Carotenoid-containing wild-type conidia were less sensitive to BL radiation than albino conidia, showing a dose enhancement factor (DEF) of 1.2 for dose levels resulting in less than 10% survival. The same strains were about equally sensitive to shortwave ultraviolet (UV) inactivation. The kinetics of BL inactivation are similar to those of photodynamic inactivation by visible light in the presence of a photosensitizing dye (methylene blue). Only limited inactivation by visible light in the absence of exogenous photosensitizers was observed. BL and UV inactivations are probably caused by different mechanisms since wild-type conidia are only slightly more resistant to BL radiation (DEF = 1.2 at 1.0% survival) than are conidia from a UV-sensitive strain (upr-1, uvs-3). The BL-induced lethal lesions are probably no cyclobutyl pyrimidine dimers since BL-inactivated Haemophilus influenzae transforming deoxyribonucleic acid is not photoreactivated by N. crassa wild-type enzyme extracts, whereas UV-inactivated transforming deoxyribonucleic acid is photoreactivable with this treatment. PMID:128556

Flavonoids Derived from Abelmoschus esculentus Attenuates UV-B Induced Cell Damage in Human Dermal Fibroblasts Through Nrf2-ARE Pathway.

PubMed

Patwardhan, Juilee; Bhatt, Purvi

2016-05-01

Ultraviolet-B (UV-B) radiation is a smaller fraction of the total radiation reaching the Earth but leads to extensive damage to the deoxyribonucleic acid (DNA) and other biomolecules through formation of free radicals altering redox homeostasis of the cell. Abelmoschus esculentus (okra) has been known in Ayurveda as antidiabetic, hypolipidemic, demulscent, antispasmodic, diuretic, purgative, etc. The aim of this study is to evaluate the protective effect of flavonoids from A. esculentus against UV-B-induced cell damage in human dermal fibroblasts. UV-B protective activity of ethyl acetate (EA) fraction of okra was studied against UV-B-induced cytotoxicity, antioxidant regulation, oxidative DNA damage, intracellular reactive oxygen species (ROS) generation, apoptotic morphological changes, and regulation of heme oxygenase-1 (HO-1) gene through nuclear factor E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway. Flavonoid-rich EA fraction depicted a significant antioxidant potential also showing presence of rutin. Pretreatment of cells with EA fraction (10-30 μg/ml) prevented UV-B-induced cytotoxicity, depletion of endogenous enzymatic antioxidants, oxidative DNA damage, intracellular ROS production, apoptotic changes, and overexpression of Nrf2 and HO-1. Our study demonstrated for the 1(st) time that EA fraction of okra may reduce oxidative stress through Nrf2-ARE pathway as well as through endogenous enzymatic antioxidant system. These results suggested that flavonoids from okra may be considered as potential UV-B protective agents and may also be formulated into herbal sunscreen for topical application. Flavonoid-enriched ethyl acetate (EA) fraction from A. esculentus protected against ultraviolet-B (UV-B)-induced oxidative DNA damageEA fraction prevented UV-B-induced cytotoxicity, depletion of endogenous enzymatic antioxidants, and intracellular reactive oxygen species productionEA fraction could reduce oxidative stress through the Nrf2-ARE PathwayEA fraction was found to be nongenotoxic and prevented apoptotic changes. Flavonoids from Abelmoschus esculentus protected from ultraviolet-B-induced damageThey were capable of reducing oxidative stress through Nrf2-ARE PathwayThey are nongenotoxic and do not possess mutagenic potentialFlavonoids from A. esculentus can be studied and explored further for its topical application as sunscreen. Abbreviations used: ABTS: 2,2'-azino-bis-(3-ethylbenzothiazoline -6-sulphonic acid), AO: Acridine orange, Analysis of variance, ARE: Antioxidant response elements, BSA: Bovine serum albumin, CAPE: Caffeic acid phenethyl ester, CAT: Catalase, DCFH-DA: 2',7'-dichlorofluorescein diacetate, DMEM: Dulbecco's modified eagle's medium, DMSO: dimethyl sulfoxide, DNA: Deoxyribonucleic acid, DPBS: Dulbecco's phosphate-buffered saline, DPPH: 2,2-diphenyl-1-picryl hydrazyl, ECL: Enhanced chemiluminescence, EDTA: Ethylenediaminetetraacetic acid, ELISA: Enzyme-linked immunosorbent assay, EtBr: Ethidium bromide, FBS: Fetal bovine serum, FE Fraction: Flavonoid-enriched fraction, FRAP: Ferric reducing antioxidant power, GPx: Glutathione peroxidase, GR: Glutathione reductase, GST: Glutathione-S-transferase, GSH: Reduced glutathione, GSSG: Oxidized glutathione, HDF: Human dermal fibroblast adult cells, HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid, HRP: Horseradish peroxidase, HO-1: Heme oxygenase-1, HPTLC: High-performance thin layer chromatography, Keap-1: Kelch-like ECH-associated protein-1, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, NaCl: sodium chloride, NFDM: nonfat dry milk, Nrf2: Nuclear factor E2-related factor 2, NQO1: NAD (P) H: Quinine oxidoreductase 1, OH: Hydroxyl ions, PBST: Phosphate-buffered saline with 0.1% tween 20, PCR: Polymerase chain reaction, PMSF: Phenylmethanesulfonyl fluoride, Rf: Retention factor, ROS: Reactive oxygen species, rRNA: Ribosomal ribonucleic acid, SDS: Sodium dodecyl sulfate, SOD: Superoxide dismutase, TLC: Thin layer chromatography, TLC-DPPH: Thin layer chromatography-2,2-diphenyl-1-picryl hydrazyl, UV: Ultraviolet, UV-A: Ultraviolet-A, UV-B: Ultraviolet-B, UV-C: Ultraviolet-C, qPCR: Quantitative polymerase chain reaction.

Towards producing novel fish gelatin films by combination treatments of ultraviolet radiation and sugars (ribose and lactose) as cross-linking agents.

PubMed

Bhat, Rajeev; Karim, A A

2014-07-01

Developing novel fish gelatin films with better mechanical properties than mammalian gelatin is a challenging but promising endeavor. Studies were undertaken to produce fish gelatin films by combining treatments with different sugars (ribose and lactose) followed 'by' 'and' ultraviolet (UV) radiation, as possible cross-linking agents. Increase in tensile strength and percent elongation at break was recorded, which was more significant in films without sugars that were exposed to UV radiation. Films with added ribose showed decreased solubility after UV treatment and exhibited higher swelling percentage than films with added lactose, which readily dissolved in water. FTIR spectra of all the films showed identical patterns, which indicated no major changes to have occurred in the functional groups as a result of interaction between gelatin, sugars and UV irradiation. The results of this study could be explored for commercial use, depending on industrial needs for either production of edible films or for food packaging purposes.

Synergistic effects of ultraviolet radiation, thermal cycling and atomic oxygen on altered and coated Kapton surfaces

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

1992-01-01

The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine their durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

Synergistic effects of ultraviolet radiation, thermal cycling, and atomic oxygen on altered and coated Kapton surfaces

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

1992-01-01

The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low Earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine there durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

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...

NASA Wiring for Space Applications Program test results

NASA Technical Reports Server (NTRS)

Vaughn, Jason A.

1995-01-01

The objectives of the NASA Wiring for Space Applications program were to investigate the effects of atomic oxygen (AO), ultraviolet (UV) radiation, and AO with UV synergistic effects on wire insulation materials. The AO exposure was on the order of 10(exp 21) atoms/sq cm and the vacuum UV radiation was on the order of 10,000 ESH. The results of these tests are presented in this document

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

NASA Technical Reports Server (NTRS)

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

2015-01-01

Radiation blocking sunscreen coatings have been developed for the protection of elastomer seals used in low-Earth-orbit (LEO). The coatings protect the seals from ultraviolet (UV) radiation and atomic oxygen (AO) damage. The coatings were developed for use on NASA docking seals. Docking seal damage from the UV and AO present in LEO can constrain mission time-line, flight mode options, and increases risk. A low level of adhesion is also required for docking seals so undocking push-off forces can be low. The coatings presented also mitigate this unwanted adhesion. Greases with low collected volatile condensable materials (CVCM) and low total mass loss (TML) were mixed with slippery and/or UV blocking powders to create the protective coatings. Coatings were applied at rates up to 2 milligrams per square centimeter. Coated seals were exposed to AO and UV in the NUV (near-UV) and UV-C wavelength ranges (300 to 400 nanometers and 254 nanometers, respectively). Ground based ashers were used to simulate the AO of space. The Sun's UV energy was mimicked assuming a nose forward flight mode, resulting in an exposure rate of 2.5 megajoules per square meter per day. Exposures between 0 and 147 megajoules per square meter (UV-C) and 245 megajoules per square meter (NUV) were accomplished. The protective coatings were durable, providing protection from UV after a simulated docking and undocking cycle. The level of protection begins to decline at coverage rates less than 0.9 milligrams per square centimeter. The leakage of seals coated with Braycote plus 20 percent Z-cote ZnO sunscreen increased by a factor of 40 after moderate AO exposure; indicating that this coating might not be suitable due to AO intolerance. Seals coated with DC-7-16.4 percent Z-cote ZnO sunscreen were not significantly affected by combined doses of 2 x 10 (sup 21) atoms per square AO with 73 megajoules per square meter UV-C. Unprotected seals were significantly damaged at UV-C exposures of 0.3 megajoules per square meter and DC-7-16.4 percent Z-cote coated seals were undamaged at all exposures up to the limits tested thus far which were 147 megajoules per square meter UV-C and 245 megajoules per square meter NUV. The coatings decreased adhesion sufficiently for docking seals at temperatures equal to or greater than -8 degrees Centigrade thus offer a simple and inexpensive way to mitigate adhesion.

Characteristic correlation study of UV disinfection performance for ballast water treatment

NASA Astrophysics Data System (ADS)

Ba, Te; Li, Hongying; Osman, Hafiiz; Kang, Chang-Wei

2016-11-01

Characteristic correlation between ultraviolet disinfection performance and operating parameters, including ultraviolet transmittance (UVT), lamp power and water flow rate, was studied by numerical and experimental methods. A three-stage model was developed to simulate the fluid flow, UV radiation and the trajectories of microorganisms. Navier-Stokes equation with k-epsilon turbulence was solved to model the fluid flow, while discrete ordinates (DO) radiation model and discrete phase model (DPM) were used to introduce UV radiation and microorganisms trajectories into the model, respectively. The UV dose statistical distribution for the microorganisms was found to move to higher value with the increase of UVT and lamp power, but moves to lower value when the water flow rate increases. Further investigation shows that the fluence rate increases exponentially with UVT but linearly with the lamp power. The average and minimum resident time decreases linearly with the water flow rate while the maximum resident time decrease rapidly in a certain range. The current study can be used as a digital design and performance evaluation tool of the UV reactor for ballast water treatment.

Incorporation of multiple cloud layers for ultraviolet radiation modeling studies

NASA Technical Reports Server (NTRS)

Charache, Darryl H.; Abreu, Vincent J.; Kuhn, William R.; Skinner, Wilbert R.

1994-01-01

Cloud data sets compiled from surface observations were used to develop an algorithm for incorporating multiple cloud layers into a multiple-scattering radiative transfer model. Aerosol extinction and ozone data sets were also incorporated to estimate the seasonally averaged ultraviolet (UV) flux reaching the surface of the Earth in the Detroit, Michigan, region for the years 1979-1991, corresponding to Total Ozone Mapping Spectrometer (TOMS) version 6 ozone observations. The calculated UV spectrum was convolved with an erythema action spectrum to estimate the effective biological exposure for erythema. Calculations show that decreasing the total column density of ozone by 1% leads to an increase in erythemal exposure by approximately 1.1-1.3%, in good agreement with previous studies. A comparison of the UV radiation budget at the surface between a single cloud layer method and a multiple cloud layer method presented here is discussed, along with limitations of each technique. With improved parameterization of cloud properties, and as knowledge of biological effects of UV exposure increase, inclusion of multiple cloud layers may be important in accurately determining the biologically effective UV budget at the surface of the Earth.

Assessing children's ultraviolet radiation exposure: the potential usefulness of a colorimeter.

PubMed

Eckhardt, L; Mayer, J A; Creech, L; Johnston, M R; Lui, K J; Sallis, J F; Elder, J P

1996-12-01

This study evaluated the colorimeter as an objective measure of children's ultraviolet (UV) radiation exposure. Fifty-eight children, ages 6 to 9 years, attended two summer measurement sessions, with 46 attending a subsequent winter session. Comparisons between summer sessions for the L* scale showed that only the upper arm significantly changed in the tanner direction, while b* scale values indicated significant tanning for all body sites. All exposed body sites changed significantly in the less tan direction between summer and winter measurements. Using colorimeters to objectively measure children's UV exposure has potential applications for skin cancer prevention programs.

Viability and Virulence of Entomopathogenic Nematodes Exposed to Ultraviolet Radiation.

PubMed

Shapiro-Ilan, David I; Hazir, Selcuk; Lete, Luis

2015-09-01

Entomopathogenic nematodes (EPNs) can be highly effective biocontrol agents, but their efficacy can be reduced due to exposure to environmental stress such as from ultraviolet (UV) radiation. Our objectives were to 1) compare UV tolerance among a broad array of EPN species, and 2) investigate the relationship between reduced nematode viability (after exposure to UV) and virulence. Nematodes exposed to a UV radiation (254 nm) for 10 or 20 min were assessed separately for viability (survival) and virulence to Galleria mellonella. We compared 9 different EPN species and 15 strains: Heterorhabditis bacteriophora (Baine, fl11, Oswego, and Vs strains), H. floridensis (332), H. georgiana (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All, Cxrd, DD136, and Sal strains), S. feltiae (SN), S. rarum (17C&E), and S. riobrave (355). In viability assessments, steinernematids, particularly strains of S. carpocapsae, generally exhibited superior UV tolerance compared with the heterorhabditids. However, some heterorhabditids tended to be more tolerant than others, e.g., H. megidis and H. bacteriophora (Baine) were most susceptible and H. bacteriophora (Vs) was the only heterorhabditid that did not exhibit a significant effect after 10 min of exposure. All heterorhabditids experienced reduced viability after 20 min exposure though several S. carpocapsae strains did not. In total, after 10 or 20 min exposure, the viability of seven nematode strains did not differ from their non-UV exposed controls. In virulence assays, steinernematids (particularly S. carpocapsae strains) also tended to exhibit higher UV tolerance. However, in contrast to the viability measurements, all nematodes experienced a reduction in virulence relative to their controls. Correlation analysis revealed that viability among nematode strains is not necessarily related to virulence. In conclusion, our results indicate that the impact of UV varies substantially among EPNs, and viability alone is not a sufficient measure for potential impact on biocontrol efficacy as other characters such as virulence may be severely affected even when viability remains high.

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.

Ultraviolet-B radiation induces modulation of antigen presentation of herpes simplex virus by human epidermal cells.

PubMed

van der Molen, R G; Out-Luiting, C; Claas, F H; Norval, M; Koerten, H K; Mommaas, A M

2001-06-01

Although ultraviolet (UV) B radiation is known to be immunosuppressive, there is little information regarding a relevant immunological endpoint to assess human subjects in vivo. Therefore, we have examined the effect of in vivo UV radiation on the ability of human epidermal cells (EC) to present herpes simplex virus (HSV) antigens to memory T cells. Human volunteers, who were seropositive for HSV, were exposed to one minimal erythemal dose (MED) for four consecutive days. EC, prepared from suction blister roofs, were co-cultured with autologous T cells in the presence of HSV. HSV antigen presentation by UV-exposed EC was increased compared with control, nonexposed EC. This up-regulation correlated with an influx of macrophages into the epidermis, which are considered to be associated with UV-induced tolerance. Altering the UV protocol to a sub-erythemal UV dose for four consecutive days or to a single high dose of 2 MED, resulted in suppressed HSV antigen presentation, without the influx of the UV-macrophages. One of the goals of the present study was to eventually use this HSV system to investigate sunscreen immunoprotection. A pilot study with a TiO2-containing sunscreen suggested that the endpoint for UV-induced immunosuppression presented here is promising to be used for human in vivo sunscreen immunoprotection studies.

Neutral and ionized polycyclic aromatic hydrocarbons, diffuse interstellar bands and the ultraviolet extinction curve

NASA Technical Reports Server (NTRS)

Salama, Farid; Allamandola, Louis John

1993-01-01

Neutral naphthalene C10H8, phenanthrene C14H10 and pyrene C16H10 absorb strongly in the ultraviolet region and may contribute to the extinction curve. High abundances are required to produce detectable structures. The cations of these polycyclic aromatic hydrocarbons (PAHs) absorb in the visible C10H8(+) has 13 discrete absorption bands which fall between 6800 and 4500 A. The strongest band at 6741 A falls close to the weak 6742 A diffuse interstellar band (DIB). Five other weaker bands also match DIBs. The possibility that C10H8(+) is responsible for some of the DIBs can be tested by searching for new DIBs at 6520 and 6151 A, other strong naphthalene cation band positions. If C10H8(+) is indeed responsible for the 6742 A feature, it accounts for 0.3% of the cosmic carbon. The spectrum of C16H10(+) is dominated by a strong band at 4435 A in an Ar matrix and 4395 A in Ne, wavelengths which fall very close to the strongest DIB at 4430 A. If C16H10(+) or a closely related pyrene-like ion, is indeed responsible for the 4430 A feature, it accounts for 0.2% of the cosmic carbon. An intense, very broad UV-to-visible continuum is reported which is associated with both ions and could explain how PAHs convert interstellar UV and visible radiation into IR radiation.

Action spectra affect variability of the climatology of biologically effective ultraviolet radiation on cloud-free days.

PubMed

Grifoni, D; Zipoli, G; Sabatini, F; Messeri, G; Bacci, L

2013-12-01

Action spectrum (AS) describes the relative effectiveness of ultraviolet (UV) radiation in producing biological effects and allows spectral UV irradiance to be weighted in order to compute biologically effective UV radiation (UVBE). The aim of this research was to study the seasonal and latitudinal distribution over Europe of daily UVBE doses responsible for various biological effects on humans and plants. Clear sky UV radiation spectra were computed at 30-min time intervals for the first day of each month of the year for Rome, Potsdam and Trondheim using a radiative transfer model fed with climatological data. Spectral data were weighted using AS for erythema, vitamin D synthesis, cataract and photokeratitis for humans, while the generalised plant damage and the plant damage AS were used for plants. The daily UVBE doses for the above-mentioned biological processes were computed and are analysed in this study. The patterns of variation due to season (for each location) and latitude (for each date) resulted as being specific for each adopted AS. The biological implications of these results are briefly discussed highlighting the importance of a specific UVBE climatology for each biological process.

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 sensing mechanisms; (ii) application of external shielding, such as covering by mud, sand or rock material; (iii) development of intrinsic UV screening pigments, such as tanning, inductive flavonoid production of plants, intracellular mycosporin production in cyanobacteria, (iv) accumulation of antioxidants and quenching substances. However, if UV damage has been induced - in spite of all avoidance efforts, organisms may restore their functionality by numerous repair processes. Repair pathways of a rich diversity and functional universality include (i) direct repair with the reversal of photochemical abnormalities, e.g. in the DNA; (ii) recombination repair removing the UV-induced abnormality by homologous recombination; and (iii) excision repair, where the section of the DNA strand containing the abnormality is removed and a repair patch is synthesized using the intact strand as a template. In addition to efficient repair systems for radiation-induced DNA injury, life has developed a variety of defense mechanisms, such as the increase in the production of stress proteins and the activation of the immune defence system. Some of these capacities have certainly already been evolved in the early biosphere, when it was exposed to the extended UV-spectrum of the sun. Only since the early Proterozoic, due to a rapid rise in the atmospheric oxygen concentration and consequently a photochemical built up of the stratospheric ozone layer, a more moderate UV radiation climate prevailed with wavelengths shorter than 295 nm being effectively cut off.

Temperature is the key to altitudinal variation of phenolics in Arnica montana L. cv. ARBO.

PubMed

Albert, Andreas; Sareedenchai, Vipaporn; Heller, Werner; Seidlitz, Harald K; Zidorn, Christian

2009-05-01

Plants in alpine habitats are exposed to many environmental stresses, in particular temperature and radiation extremes. Recent field experiments on Arnica montana L. cv. ARBO indicated pronounced altitudinal variation in plant phenolics. Ortho-diphenolics increased with altitude compared to other phenolic compounds, resulting in an increase in antioxidative capacity of the tissues involved. Factors causing these variations were investigated by climate chamber (CC) experiments focusing on temperature and ultraviolet (UV)-B radiation. Plants of A. montana L. cv. ARBO were grown in CCs under realistic climatic and radiation regimes. Key factors temperature and UV-B radiation were altered between different groups of plants. Subsequently, flowering heads were analyzed by HPLC for their contents of flavonoids and caffeic acid derivatives. Surprisingly, increased UV-B radiation did not trigger any change in phenolic metabolites in Arnica. In contrast, a pronounced increase in the ratio of B-ring ortho-diphenolic (quercetin) compared to B-ring monophenolic (kaempferol) flavonols resulted from a decrease in temperature by 5 degrees C in the applied climate regime. In conclusion, enhanced UV-B radiation is probably not the key factor triggering shifts in the phenolic composition in Arnica grown at higher altitudes but rather temperature, which decreases with altitude.

[Effect of lanthanum on the flavonoids contents and antioxidant capacity in soybean seedling under ultraviolet-B stress].

PubMed

Peng, Qi; Zhou, Qing

2008-07-01

Dynamic state of antioxidant capacity of flavonoids was investigated for a further demonstration of alleviating the damage of the UV-B radiation in the La-treated soybean seedlings under UV-B stress. Using hydroponics culture, the effects of lanthanum on the contents of flavonoids and its ability of antioxidant under elevated ultraviolet-B radiation (280-320 nm) was studied in this paper. The results showed flavonoids contents in Soybean seedlings during the stress and convalescent period increase firstly and then reduce. Membrane permeability and MDA contents increase firstly (1st-5th day) and then fall (6th to 11th day). A similar change of flavonoids contents and clearance of flavonoids scavenging O2*- and *OH in soybean seedlings occur; the flavonoids contents La(III) + UV-B > UV-B > La(III) > CK, La(III) + T1 > La(III) + T2. Plasma membrane permeability and MAD contents UV-B> La(III) + UV-B > CK > La(III), La(III) + T2 > La(III) + T1. The ability of Scavenging activities of free radical (O2*-, *OH) La(III) + UV-B > UV-B > La(III) > CK. It suggested that the regulative effect of La(III) on flavonoids, improved the metabolism of ROS, diminished the concentration of MDA and maintained normal Plasma membrane permeability, and that its protective effect against low UV-B radiation was superior to that of high UV-B radiation. To conclude, the defensive effect of La(III) on soybean seedlings under UV-B stress was carried out on the layer of defense system.

Transmittance of tinted and UV-blocking disposable contact lenses.

PubMed

Harris, M G; Haririfar, M; Hirano, K Y

1999-03-01

Tinted and ultraviolet (UV)-blocking disposable contact lenses have become increasingly popular over the last decade. Wearers of UV-blocking contact lenses could benefit greatly by protecting their eyes from potential UV radiation damage. A Uvikon 930 dual beam spectrophotometer was used to measure three enhancement-tinted lenses (royal blue, evergreen, and aqua), two types of UV-blocking lenses, and two types of non-UV-blocking lenses. Enhancement-tinted lenses did show a decrease in transmittance at certain wavelengths on the visible spectrum, but they did not reduce the transmittance of UV radiation to the extent of the UV-blocking lenses designed specifically for this purpose.

Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

NASA Astrophysics Data System (ADS)

Gulati, P.; Prakash, R.; Pal, U. N.; Kumar, M.; Vyas, V.

2014-07-01

A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl2 deteriorates the performance of the developed source and around 2% Cl2 in this source produced optimum results. Furthermore, an addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.

Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

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

Gulati, P., E-mail: pgulati1512@gmail.com; Department of Physics, Banasthali University, P.O. Banasthali Vidyapith, Rajasthan 304022; Prakash, R.

2014-07-07

A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl{sub 2} deteriorates the performance of the developed source and around 2% Cl{sub 2} in this source produced optimum results. Furthermore, anmore » addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.« less

A Comprehensive Review of Semiconductor Ultraviolet Photodetectors: From Thin Film to One-Dimensional Nanostructures

PubMed Central

Sang, Liwen; Liao, Meiyong; Sumiya, Masatomo

2013-01-01

Ultraviolet (UV) photodetectors have drawn extensive attention owing to their applications in industrial, environmental and even biological fields. Compared to UV-enhanced Si photodetectors, a new generation of wide bandgap semiconductors, such as (Al, In) GaN, diamond, and SiC, have the advantages of high responsivity, high thermal stability, robust radiation hardness and high response speed. On the other hand, one-dimensional (1D) nanostructure semiconductors with a wide bandgap, such as β-Ga2O3, GaN, ZnO, or other metal-oxide nanostructures, also show their potential for high-efficiency UV photodetection. In some cases such as flame detection, high-temperature thermally stable detectors with high performance are required. This article provides a comprehensive review on the state-of-the-art research activities in the UV photodetection field, including not only semiconductor thin films, but also 1D nanostructured materials, which are attracting more and more attention in the detection field. A special focus is given on the thermal stability of the developed devices, which is one of the key characteristics for the real applications. PMID:23945739

Efficacy and durability of ultraviolet tints in CR-39 ophthalmic lenses.

PubMed

Lee, D Y; Brown, W L; Trachimowicz, R

1997-11-01

Ocular protection from solar ultraviolet (UV) radiation has been emphasized in recent years as a result of the thinning of the ozone layer in the atmosphere. The purpose of this study was to evaluate the absorptive properties of UV tints in CR-39 lenses. We used a spectrophotometer to measure the UV transmittance of three groups of UV tinted CR-39 lenses, including (1) lenses tinted by local optical laboratories: (2) lenses tinted by us, using commercially available dyes: and (3) stock UV lenses that have UV absorptive molecules throughout the lens. We also tested the durability of these tints to daily washing/drying by measuring their UV transmittance characteristics at 3, 6, and 12 months. All the tested lenses absorbed all of the UV-B and at least 99% of UV-A. The durability of these UV tints when exposed to daily washing/drying was excellent: all lenses continued to absorb all of the UV-B and at least 99% of UV-A after 1 year. These data suggest that UV tinted CR-39 lenses provide protection against UV radiation that meets the ANSI Z80.3-1996 Standard for non-prescription sunglasses and fashion eyewear. Furthermore, normal daily washing/drying for 1 year does not cause a significant decrease in the protective effect of the UV tint.

The effect of ultraviolet radiation on the pathogenesis of Candida albicans in mice

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

Denkins, Y.M.

1991-01-01

This dissertation addresses questions concerning the effects of UV radiation on the pathogenesis of opportunistic fungal pathogens such as Candida albicans. UV radiation decreased the survival of Candida-infected mice; however, no correlation was found between suppression of the delayed type hypersensitivity (DTH) response and the course of lethal infection. This suggested that DTH was not protective against lethal disease with this organism. UV radiation also changed the persistence of the organism in the internal organs. UV-irradiated, infected animals had increased numbers of Candida in their kidneys compared to non-irradiated mice. Sensitization prior to UV irradiation aided clearance of the organismmore » from the kidneys of UV-irradiated mice. These data show that UV radiation suppresses cell-mediated immunity to Candida albicans in mice and increases mortality of Candida-infected mice. Moreover, the data suggest that an increase in environmental UV radiation could increase the severity of pathogenic infections.« less

Perilla frutescens leaves extract ameliorates ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin.

PubMed

Bae, Jung-Soo; Han, Mira; Shin, Hee Soon; Kim, Min-Kyoung; Shin, Chang-Yup; Lee, Dong Hun; Chung, Jin Ho

2017-01-04

Perilla frutescens (L.) Britt. (Lamiaceae) is a traditional herb that is consumed in East Asian countries as a traditional medicine. This traditional herb has been documented for centuries to treat various diseases such as depression, allergies, inflammation and asthma. However, the effect of Perilla frutescens on skin has not been characterized well. The present study aimed to investigate the effect of Perilla frutescens leaves extract (PLE) on ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin. Human dermal fibroblasts and Skh-1 hairless mice were irradiated with UV and treated with PLE. Protein and mRNA levels of various target molecules were analyzed by western blotting and quantitative RT-PCR, respectively. Histological changes of mouse skin were analyzed by H&E staining. To elucidate underlying mechanism of PLE, activator protein-1 (AP-1) DNA binding assay and the measurement of reactive oxygen species (ROS) were performed. PLE significantly inhibited basal and UV-induced MMP-1 and MMP-3 expression dose-dependently, and also decreased UV-induced phosphorylation of extracellular signal-regulated kinases and c-Jun N-terminal kinases. This inhibitory effects of PLE on MMP-1 and MMP-3 were mediated by reduction of ROS generation and AP-1 DNA binding activity induced by UV. Furthermore, PLE promoted type I procollagen production irrespective of UV irradiation. In the UV-irradiated animal model, PLE significantly reduced epidermal skin thickness and MMP-13 expression induced by UV. Our results demonstrate that PLE has the protective effect against UV-induced dermal matrix damage. Therefore, we suggest that PLE can be a potential agent for prevention of skin aging. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inactivation of uropathogenic Escherichia coli in ground chicken meat using high pressure processing and gamma radiation, and in purge and chicken meat surfaces by ultraviolet light

USDA-ARS?s Scientific Manuscript database

Uropathogenic Escherichia coli (UPEC) are common contaminants in meat and poultry. Nonthermal food safety intervention technologies used to improve safety and shelf-life of both human and pet foods can include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV...

The influence of ultra-violet radiation on chicken hatching.

PubMed

Veterány, Ladislav; Hluchý, Svätoslav; Veterányová, Anna

2004-01-01

The influence of UV-B radiation on embryonic development of chickens Hampshire breed was investigated. The set eggs with the average weight of 60.0 +/- 0.5 g were divided into six groups. The chickens in the control group C were hatched in the darkness. The chicken embryos in experimental groups were, during their incubation, influenced by UV light: in E1 (1 h a day), in E2 (2h a day), in E3 (3 h a day), in E4 (4 h a day), and in E5 (5 h a day). After the experiment, we can state that UV radiation appealing on chickens embryos of shorter time (1-2 h) was reflected in decreasing embryonic mortality in experimental group E1 (1.27 +/- 0.14%), the embryonic development was accelerated and the weight of hatched chickens was increased in group E2 (492.43 +/- 5.02 h and 47.83 +/- 2.62 g, respectively). The negative influence of UV radiation was reflected while it is longer appealing on chickens embryos (for 3-5 h), mainly by increased embryonic mortality in groups E3 (10.27 +/- 1.65%), E4 (58.09 +/- 3.12%), and E5 (100.00 +/- 0.00%). The results obtained are highly significant (p<0.001) in comparison with a control group C, as well as, with the experimental groups E1 and E2.

Assessment of the impact of increased solar ultraviolet radiation upon marine ecosystems

NASA Technical Reports Server (NTRS)

Vandyke, H.; Worrest, R. C.

1976-01-01

Data was provided to assess the potential impact upon marine ecosystems if space shuttle operations contribute to a reduction of the stratospheric ozone layer. The potential for irreversible damage to the productivity, structure and/or functioning of a model estuarine ecosystem by increased UV-B radiation was established. The sensitivity of key community components (the primary producers) to increased UV-B radiation was delineated.

Combination of UV-C treatment and Metschnikowia pulcherrimas for controlling Alternaria rot in postharvest winter jujube fruit.

PubMed

Guo, Dongqi; Zhu, Lixia; Hou, Xujie

2015-01-01

The potential of using antagonistic yeast Metschnikowia pulcherrimas alone or in combination with ultraviolet-C (UV-C) treatment for controlling Alternaria rot of winter jujube, and its effects on postharvest quality of fruit was investigated. The results showed that spore germination of Alternaria alternata was significantly inhibited by each of the 3 doses (1, 5, and 10 kJ m(-2) ) in vitro. In vivo, UV-C treatment (5 kJ m(-2) ) or antagonist yeast was capable of reducing the percentage of infected wounds and lesion diameter in artificially inoculated jujube fruits, however, in fruit treated with combination of UV-C treatment and M. pulcherrima, the percentage of infected wounds and lesion diameter was only 16.0% and 0.60 cm, respectively. The decay incidence on winter jujube fruits treated with the combination of UV-C treatment and M. pulcherrima was 23% after storage at 0 ± 1 °C for 45 d followed by 22 °C for 7 d. None of the treatments impaired quality parameters of jujube fruit. Thus, the combination of UV-C radiation and M. pulcherrima could be an alternative to synthetic fungicides for controlling postharvest Alternaria rot of winter jujube. © 2014 Institute of Food Technologists®

[Ultraviolet exposure from indoor tanning devices as a potential source of health risks: Basic knowledge of the proper use of these devices for practical users, physicians and solarium staff].

PubMed

Malinowska-Borowska, Jolanta; Janosik, Elżbieta

2017-07-26

Bearing in mind the adverse health effects of exposure to ultraviolet (UV) radiation in solarium, especially the risk of carcinogenesis, there is a need to adopt legal regulations by relevant Polish authorities. They should set out the principles for indoor tanning studios operation, supervision and service of the technical parameters of tanning devices and training programs to provide the staff with professional knowledge and other aspects of safety in these facilities. The mechanism of the harmful effects of ultraviolet radiation on the human body, scale of overexposure, resulting from excessive sunbathing are described. Methods for estimating UV exposure and possible actions aimed at reducing the overexposure and preventing from cancer development caused by UV are also presented in this paper. Med Pr 2017;68(5):653-665. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

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.

Caffeine Eye Drops Protect Against UV-B Cataract

PubMed Central

Kronschläger, Martin; Löfgren, Stefan; Yu, Zhaohua; Talebizadeh, Nooshin; Varma, Shambhu D.; Söderberg, Per

2013-01-01

The purpose of this study was to investigate if topically applied caffeine protects against in vivo ultraviolet radiation cataract and if so, to estimate the protection factor. Three experiments were carried out. First, two groups of Sprague-Dawley rats were pre-treated with a single application of either placebo or caffeine eye drops in both eyes. All animals were then unilaterally exposed in vivo to 8 kJ/m2 UV-B radiation for 15 min. One week later, the lens GSH levels were measured and the degree of cataract was quantified by measurement of in vitro lens light scattering. In the second experiment, placebo and caffeine pre-treated rats were divided in five UV-B radiation dose groups, receiving 0.0, 2.6, 3.7, 4.5 or 5.2 kJ/m2 UV-B radiation in one eye. Lens light scattering was determined after one week. In the third experiment, placebo and caffeine pre-treated rats were UV-B-exposed and the presence of activated caspase-3 was visualized by immunohistochemistry. There was significantly less UV-B radiation cataract in the caffeine group than in the placebo group (95% confidence interval for mean difference in lens light scattering between the groups = 0.10 ± 0.05 tEDC), and the protection factor for caffeine was 1.23. There was no difference in GSH levels between the placebo- and the caffeine group. There was more caspase-3 staining in UV-B-exposed lenses from the placebo group than in UV-B-exposed lenses from the caffeine group. Topically applied caffeine protects against ultraviolet radiation cataract, reducing lens sensitivity 1.23 times. PMID:23644096

TECHNIQUES FOR DETERMINING UV EXPOSURE IN COASTAL WATERS: CASE STUDY IN SOUTH FLORIDA

EPA Science Inventory

The photosynthesis of coral reefs is inhibited by solar ultraviolet (UV) radiation and UV in combination with unusually high sea surface temperatures is believed to play an important role in coral bleaching. In this presentation we use a new technique based on remotely sensed oce...

Modeling UV-B Effects on Primary Production Throughout the Southern Ocean Using Multi-Sensor Satellite Data

NASA Technical Reports Server (NTRS)

Lubin, Dan

2001-01-01

This study has used a combination of ocean color, backscattered ultraviolet, and passive microwave satellite data to investigate the impact of the springtime Antarctic ozone depletion on the base of the Antarctic marine food web - primary production by phytoplankton. Spectral ultraviolet (UV) radiation fields derived from the satellite data are propagated into the water column where they force physiologically-based numerical models of phytoplankton growth. This large-scale study has been divided into two components: (1) the use of Total Ozone Mapping Spectrometer (TOMS) and Special Sensor Microwave Imager (SSM/I) data in conjunction with radiative transfer theory to derive the surface spectral UV irradiance throughout the Southern Ocean; and (2) the merging of these UV irradiances with the climatology of chlorophyll derived from SeaWiFS data to specify the input data for the physiological models.

Flame Detector

NASA Technical Reports Server (NTRS)

1990-01-01

Scientific Instruments, Inc. has now developed a second generation, commercially available instrument to detect flames in hazardous environments, typically refineries, chemical plants and offshore drilling platforms. The Model 74000 detector incorporates a sensing circuit that detects UV radiation in a 100 degree conical field of view extending as far as 250 feet from the instrument. It operates in a bandwidth that makes it virtually 'blind' to solar radiation while affording extremely high sensitivity to ultraviolet flame detection. A 'windowing' technique accurately discriminates between background UV radiation and ultraviolet emitted from an actual flame, hence the user is assured of no false alarms. Model 7410CP is a combination controller and annunciator panel designed to monitor and control as many as 24 flame detectors. *Model 74000 is no longer being manufactured.

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

Evaluating Ultraviolet Radiation Exposures Determined from TOMS Satellite Data at Sites of Amphibian Declines in Central and South America

NASA Technical Reports Server (NTRS)

Middleton, Elizabeth M.; Smith, David E. (Technical Monitor)

2000-01-01

Many amphibian species have experienced substantial population declines, or have disappeared altogether, during the last several decades at a number of amphibian census sites in Central and South America. This study addresses the use of satellite-derived trends in solar ultraviolet-B (UV-B; 280-320 nm) radiation exposures at these sites over the last two decades, and is intended to demonstrate a role for satellite observations in determining whether UV-B radiation is a contributing factor in amphibian declines. UV-B radiation levels at the Earth's surface were derived from the Total Ozone Mapping Spectrometer (TOMS) satellite data, typically acquired daily since 1979. These data were used to calculate the daily erythemal (sunburning) UV-B, or UV-B(sub ery), exposures at the latitude, longitude, and elevation of each of 20 census sites. The annually averaged UV-B(sub ery) dose, as well as the maximum values, have been increasing in both Central and South America, with higher levels received at the Central American sites. The annually averaged UV-B(sub ery) exposures increased significantly from 1979-1998 at all 11 Central American sites examined (r(exp 2) = 0.60 - 0.79; P<=0.015), with smaller but significant increases at five of the nine South American sites (r(exp 2) = 0.24-0.42; P<=0.05). The contribution of the highest UV-B(sub ery) exposure levels (>= 6750 J/sq m*d) to the annual UV-B(sub ery) total has increased from approx. 5% to approx. 15% in Central America over the 19 year period, but actual daily exposures for each species are unknown. Synergy among UV-B radiation and other factors, especially those associated with alterations of water chemistry (e.g., acidification) in aqueous habitats is discussed. These findings justify further research concerning whether UV-B(sub ery) radiation plays a role in amphibian population declines and extinctions.

Effects of ultraviolet radiation and contaminant-related stressors on arctic freshwater ecosystems.

PubMed

Wrona, Frederick J; Prowse, Terry D; Reist, James D; Hobbie, John E; Lévesque, Lucie M J; Macdonald, Robie W; Vincent, Warwick F

2006-11-01

Climate change is likely to act as a multiple stressor, leading to cumulative and/or synergistic impacts on aquatic systems. Projected increases in temperature and corresponding alterations in precipitation regimes will enhance contaminant influxes to aquatic systems, and independently increase the susceptibility of aquatic organisms to contaminant exposure and effects. The consequences for the biota will in most cases be additive (cumulative) and multiplicative (synergistic). The overall result will be higher contaminant loads and biomagnification in aquatic ecosystems. Changes in stratospheric ozone and corresponding ultraviolet radiation regimes are also expected to produce cumulative and/or synergistic effects on aquatic ecosystem structure and function. Reduced ice cover is likely to have a much greater effect on underwater UV radiation exposure than the projected levels of stratospheric ozone depletion. A major increase in UV radiation levels will cause enhanced damage to organisms (biomolecular, cellular, and physiological damage, and alterations in species composition). Allocations of energy and resources by aquatic biota to UV radiation protection will increase, probably decreasing trophic-level productivity. Elemental fluxes will increase via photochemical pathways.

Study of the ultraviolet emission of the electrode coatings of arc welding.

PubMed

Garcia-Guinea, J; Correcher, V; Lombardero, M; Gonzalez-Martin, R

2004-08-01

The optical emission properties of several minerals components employed in electrode coatings of arc welding have been investigated. The X-ray diffraction analysis shows that the composition of 14 commercial electrode coatings collected from different countries (Spain, France, UK, Poland, Argentina and Germany), consists of quartz, calcite, sodium and potassium rich feldspars, muscovite and rutile. The natural thermal stimulated luminescence (TSL) of these mineral phases, measured in the range of 200-800 nm at different temperatures (from room temperature to 400 degrees C) displays UV-A (wavelengths of 320 nm to 400 nm) and UV-B (from 280 nm to 320 nm) emissions, with the exception of rutile. The UV-B radiation, commonly described as the most dangerous form of radiation to human life, is here associated with structural defects in the crystallographic lattice of the mineral components of electrode coatings.

DEMONSTRATION BULLETIN: CAV-OX ULTRAVIOLET OXIDATION PROCESS MAGNUM WATER TECHNOLOGY

EPA Science Inventory

The CAV-OX® technology (see Fig- ure 1) destroys organic contaminants, including chlorinated hy- drocarbons, in water. The process uses hydrogen peroxide, hy- drodynamic cavitation, and ultraviolet (UV) radiation to photolyze and oxidize organic compounds present in water at ...

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

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

PubMed

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

2017-10-10

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

Assessing children's ultraviolet radiation exposure: the potential usefulness of a colorimeter.

PubMed Central

Eckhardt, L; Mayer, J A; Creech, L; Johnston, M R; Lui, K J; Sallis, J F; Elder, J P

1996-01-01

OBJECTIVES: This study evaluated the colorimeter as an objective measure of children's ultraviolet (UV) radiation exposure. METHODS: Fifty-eight children, ages 6 to 9 years, attended two summer measurement sessions, with 46 attending a subsequent winter session. RESULTS: Comparisons between summer sessions for the L* scale showed that only the upper arm significantly changed in the tanner direction, while b* scale values indicated significant tanning for all body sites. All exposed body sites changed significantly in the less tan direction between summer and winter measurements. CONCLUSIONS: Using colorimeters to objectively measure children's UV exposure has potential applications for skin cancer prevention programs. PMID:9003142

Analysis of ultraviolet exposure effects on the surface properties of epoxy/graphene nanocomposite films on Mylar substrate

NASA Astrophysics Data System (ADS)

Clausi, Marialaura; Santonicola, M. Gabriella; Schirone, Luigi; Laurenzi, Susanna

2017-05-01

In this paper, we present a study of the effects generated by exposure to UV-C radiation on nanocomposite films made of graphene nanoplatelets dispersed in an epoxy matrix. The nanocomposite films, at different nanoparticle size and concentration, were fabricated on Mylar substrate using the spin coating process. The effects of UV-C irradiation on the surface hydrophobicity and on the electrical properties of the epoxy/graphene films were investigated using contact angle measurements and electrical impedance spectroscopy, respectively. According to our results, the UV-C irradiation selectively degrades the polymer matrix of the nanocomposite films, giving rise to more conductive and hydrophobic layers due to exposure of the graphene component of the composite material. The results presented here have important implications in the design of spacecraft components and structures destined for long-term space missions.

Effect of UV-C radiation on bioactive compounds of pineapple (Ananas comosus L. Merr.) by-products.

PubMed

Freitas, Ana; Moldão-Martins, Margarida; Costa, Helena S; Albuquerque, Tânia G; Valente, Ana; Sanches-Silva, Ana

2015-01-01

The industrial processing of pineapple generates a high quantity of by-products. To reduce the environmental impact of these by-products and the inherent cost of their treatment, it is important to characterise and valorise these products, converting them into high added value products. Ultra-violet radiation is one of the main sustainable sanitation techniques for fruits. Since this radiation can induce plant stress which can promote the biosynthesis of bioactive compounds, it is important to evaluate its effect in fruits. The amounts of vitamins (C and E) and carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, neoxanthin, violaxanthin and zeaxanthin) in pineapple by-products (core and rind) were analysed before and after treatment with UV radiation. All treated and untreated pineapple by-products contained β-carotene as the main carotenoid (rind, 2537-3225 µg; and core, 960-994 µg 100 g(-1) DW). Pineapple rind also contained lutein (288-297 µg 100 g(-1) DW) and α-carotene (89-126 µg 100 g(-1) DW). The results provide evidence of the potential of pineapple by-products as a source of bioactive compounds with antioxidant activity, which can be used by pharmaceutical, cosmetics and food industries. In addition, UV-C was shown to be a treatment that can add nutritional value to pineapple by-products. © 2014 Society of Chemical Industry.

Assessing the effects of ultraviolet radiation on the photosynthetic potential in Archean marine environments

NASA Astrophysics Data System (ADS)

Avila-Alonso, Dailé; Baetens, Jan M.; Cardenas, Rolando; de Baets, Bernard

2017-07-01

In this work, the photosynthesis model presented by Avila et al. in 2013 is extended and more scenarios inhabited by ancient cyanobacteria are investigated to quantify the effects of ultraviolet (UV) radiation on their photosynthetic potential in marine environments of the Archean eon. We consider ferrous ions as blockers of UV during the Early Archean, while the absorption spectrum of chlorophyll a is used to quantify the fraction of photosynthetically active radiation absorbed by photosynthetic organisms. UV could have induced photoinhibition at the water surface, thereby strongly affecting the species with low light use efficiency. A higher photosynthetic potential in early marine environments was shown than in the Late Archean as a consequence of the attenuation of UVC and UVB by iron ions, which probably played an important role in the protection of ancient free-floating bacteria from high-intensity UV radiation. Photosynthetic organisms in Archean coastal and ocean environments were probably abundant in the first 5 and 25 m of the water column, respectively. However, species with a relatively high efficiency in the use of light could have inhabited ocean waters up to a depth of 200 m and show a Deep Chlorophyll Maximum near 60 m depth. We show that the electromagnetic radiation from the Sun, both UV and visible light, could have determined the vertical distribution of Archean marine photosynthetic organisms.

Exposure to solar ultraviolet radiation is associated with a decreased folate status in women of childbearing age.

PubMed

Borradale, D; Isenring, E; Hacker, E; Kimlin, M G

2014-02-05

In vitro studies indicate that folate in collected human blood is vulnerable to degradation after exposure to ultraviolet (UV) radiation. This has raised concerns about folate depletion in individuals with high sun exposure. Here, we investigate the association between personal solar UV radiation exposure and serum folate concentration, using a three-week prospective study that was undertaken in females aged 18-47years in Brisbane, Australia (153 E, 27 S). Following two weeks of supplementation with 500μg of folic acid daily, the change in serum folate status was assessed over a 7-day period of measured personal sun exposure. Compared to participants with personal UV exposures of <200 Joules per day, participants with personal UV exposures of 200-599 and >600 Joules per day had significantly higher depletion of serum folate (p=0.015). Multivariable analysis revealed personal UV exposure as the strongest predictor accounting for 20% of the overall change in serum folate (Standardised B=-0.49; t=-3.75; p=<0.01). These data show that increasing solar UV radiation exposures reduces the effectiveness of folic acid supplementation. The consequences of this association may be most pronounced for vulnerable individuals, such as women who are pregnant or of childbearing age with high sun exposures. Copyright © 2014 Elsevier B.V. All rights reserved.

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 decline in photosynthetic competence when suddenly exposed to near-ambient UV-B levels, but exhibited pronounced acclimative responses.

Solar ultraviolet-B radiation and vitamin D: a cross-sectional population-based study using data from the 2007 to 2009 Canadian Health Measures Survey.

PubMed

Greenfield, Jamie A; Park, Philip S; Farahani, Ellie; Malik, Suneil; Vieth, Reinhold; McFarlane, Norman A; Shepherd, Theodore G; Knight, Julia A

2012-08-15

Exposure to solar ultraviolet-B (UV-B) radiation is a major source of vitamin D3. Chemistry climate models project decreases in ground-level solar erythemal UV over the current century. It is unclear what impact this will have on vitamin D status at the population level. The purpose of this study was to measure the association between ground-level solar UV-B and serum concentrations of 25-hydroxyvitamin D (25(OH)D) using a secondary analysis of the 2007 to 2009 Canadian Health Measures Survey (CHMS). Blood samples collected from individuals aged 12 to 79 years sampled across Canada were analyzed for 25(OH)D (n = 4,398). Solar UV-B irradiance was calculated for the 15 CHMS collection sites using the Tropospheric Ultraviolet and Visible Radiation Model. Multivariable linear regression was used to evaluate the association between 25(OH)D and solar UV-B adjusted for other predictors and to explore effect modification. Cumulative solar UV-B irradiance averaged over 91 days (91-day UV-B) prior to blood draw correlated significantly with 25(OH)D. Independent of other predictors, a 1 kJ/m² increase in 91-day UV-B was associated with a significant 0.5 nmol/L (95% CI 0.3-0.8) increase in mean 25(OH)D (P = 0.0001). The relationship was stronger among younger individuals and those spending more time outdoors. Based on current projections of decreases in ground-level solar UV-B, we predict less than a 1 nmol/L decrease in mean 25(OH)D for the population. In Canada, cumulative exposure to ambient solar UV-B has a small but significant association with 25(OH)D concentrations. Public health messages to improve vitamin D status should target safe sun exposure with sunscreen use, and also enhanced dietary and supplemental intake and maintenance of a healthy body weight.

Nitric oxide alleviates oxidative damage induced by enhanced ultraviolet-B radiation in cyanobacterium.

PubMed

Xue, Lingui; Li, Shiweng; Sheng, Hongmei; Feng, Huyuan; Xu, Shijian; An, Lizhe

2007-10-01

To study the role of nitric oxide (NO) on enhanced ultraviolet-B (UV-B) radiation (280-320 nm)-induced damage of Cyanobacterium, the growth, pigment content, and antioxidative activity of Spirulina platensis-794 cells were investigated under enhanced UV-B radiation and under different chemical treatments with or without UV-B radiation for 6 h. The changes in chlorophyll-a, malondialdehyde content, and biomass confirmed that 0.5 mM: sodium nitroprusside (SNP), a donor of nitric oxide (NO), could markedly alleviate the damage caused by enhanced UV-B. Specifically, the biomass and the chlorophyll-a content in S. platensis-794 cells decreased 40% and 42%, respectively under enhanced UV-B stress alone, but they only decreased 10% and 18% in the cells treated with UV-B irradiation and 0.5 mM: SNP. Further experiments suggested that NO treatment significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the accumulation of O (2)(-) in enhanced UV-B-irradiated cells. SOD and CAT activity increased 0.95- and 6.73-fold, respectively. The accumulation of reduced glutathione (GSH) increased during treatment with 0.5 mM: SNP in normal S. platensis cells, but SNP treatment could inhibit the increase of GSH in enhanced UV-B-stressed S. platensis cells. Thus, these results suggest that NO can strongly alleviate oxidative damage caused by UV-B stress by increasing the activities of SOD, peroxidase, CAT, and the accumulation of GSH, and by eliminating O (2)(-) in S. platensis-794 cells. In addition, the difference of NO origin between plants and cyanobacteria are discussed.

Is the Global Solar UV Index an Effective Instrument for Promoting Sun Protection? A Systematic Review

ERIC Educational Resources Information Center

Italia, Nadia; Rehfuess, Eva A.

2012-01-01

Exposure to ultraviolet radiation is an important risk factor for skin cancer. The Global Solar Ultraviolet Index (UVI) was developed as a tool to visualize the amount of harmful radiation and to encourage people to use sun protection. We conducted a systematic review of the effectiveness of the UVI. We employed a comprehensive search strategy to…

Laboratory Instrumentation Design Research for Scalable Next Generation Epitaxy: Non-Equilibrium Wide Application Epitaxial Patterning by Intelligent Control (NEW-EPIC). Volume 1. 3D Composition/Doping Control via Micromiror Patterned Deep UV Photodesorption: Revolutionary in situ Characterization/Control

DTIC Science & Technology

2009-02-19

magnesium dopant concentration. A digital micromirror device is introduced to pattern incident UV radiation during InGaN growth, demonstrating that the...magnesium dopant concentration. A digital micromirror device is introduced to pattern incident UV radiation during InGaN growth, demonstrating that the...successful compositional patterning of InGaN using in situ digital micromirror device (DMD) patterning of ultraviolet (UV

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

PubMed Central

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

2013-01-01

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

UV EFFECTS IN TOOTH ENAMEL AND THEIR POSSIBLE APPLICATION IN EPR DOSIMETRY WITH FRONT TEETH

PubMed Central

Sholom, S.; Desrosiers, M.; Chumak, V.; Luckyanov, N.; Simon, S.L.; Bouville, A.

2009-01-01

The effects of ultraviolet (UV) radiation on ionizing radiation biodosimetry were studied in human tooth enamel samples using the technique of electron paramagnetic resonance (EPR) in X-band. For samples in the form of grains, UV-specific EPR spectra were spectrally distinct from that produced by exposure to gamma radiation. From larger enamel samples, the UV penetration depth was determined to be in the 60–120 μm range. The difference in EPR spectra from UV exposure and from exposure to gamma radiation samples was found to be a useful marker of UV equivalent dose (defined as the apparent contribution to the gamma dose in mGy that results from UV radiation absorption) in tooth enamel. This concept was preliminarily tested on front teeth from inhabitants of the region of the Semipalatinsk Nuclear Test Site (Kazakhstan) who might have received some exposure to gamma radiation from the nuclear tests conducted there as well as from normal UV radiation in sunlight. The technique developed here to quantify and subtract the UV contribution to the measured tooth is currently limited to cumulative dose measurements with a component of UV equivalent dose equal to or greater than 300 mGy. PMID:20065706

Technology Evaluation Report - SITE PROGRAM DEMONSTRATION OF THE ULTROX INTERNATIONAL ULTRAVIOLET RADIATION OXIDATION TECHNOLOGY

EPA Science Inventory

In support of EPA's Superfund Innovative Technology Evaluation (SITE) Program, this report presents the results of the Ultrox International technology demonstration. The Ultrox® technology (a registered trademark of Ultrox International) simultaneously uses ultraviolet (UV) radi...

Effect of lanthanum(III) on the production of ethylene and reactive oxygen species in soybean seedlings exposed to the enhanced ultraviolet-B radiation.

PubMed

Yang, Qing; Li, Yueli; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2014-06-01

The enhanced ultraviolet-B (UV-B) radiation caused by ozone depletion may exert deleterious effects on plants. Therefore, studies on the effect of UV-B radiation on plants, as well as studies on the methods for alleviating the deleterious effects by chemical control, are of great significance. In this study, after soybean (Glycine max) seedlings were exposed to UV-B radiation (10.2 and 13.8kJ m(-2)day(-1)) for 5 days and the followed 6 days of restoration, respectively, the effects of 20mg L(-1) lanthanum (III) [La(III)] on leaf phenotype, photosynthetic rate, and production of ethylene and reactive oxygen species (ROS) were investigated. The results indicated that the exposure to 10.2 and 13.8kJ m(-2)day(-1) UV-B radiation could cause injury to the leaf phenotype, and lead to the decrease in the content of chlorophyll and the net photosynthetic rate, and the increase in the contents of ROS, ethylene and 1-aminocyclopropanecarboxylic acid, and 1-aminocyclopropanecarboxylic acid synthase activity in soybean seedlings. Following the withdrawal of the enhanced UV-B radiation, the above mentioned parameters gradually recovered, and the recovery of soybean seedlings exposed to 10.2kJ m(-2)day(-1) UV-B radiation was faster than those in soybean seedlings exposed to 13.8kJ m(-2)day(-1) UV-B radiation. The leaf injury and the changes in the above indices that were induced by the enhanced UV-B radiation, especially at 10.2kJ m(-2)day(-1), were alleviated after the pretreatment of soybean seedlings with 20mg L(-1) La(III). The results of the correlation analysis demonstrated that the injury to the leaf phenotype and the decrease in the photosynthetic rate of soybean seedlings were correlated with the increase in the ROS content that was induced by ethylene in soybean seedlings. The pretreatment with 20mg L(-1) La(III) alleviated the injury caused by the enhanced UV-B radiation through the regulation of the ROS production. Copyright © 2014 Elsevier Inc. All rights reserved.

Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

PubMed

Kobayashi, Fumihisa; Maki, Teruya; Kakikawa, Makiko; Yamada, Maromu; Puspitasari, Findya; Iwasaka, Yasunobu

2015-05-01

Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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).

Suitability of surface acoustic wave oscillators fabricated using low temperature-grown AlN films on GaN/sapphire as UV sensors.

PubMed

Chen, Tzu Chieh; Lin, Yueh Ting; Lin, Chung Yi; Chen, W C; Chen, Meei Ru; Kao, Hui-Ling; Chyi, J I; Hsu, C H

2008-02-01

Epitaxial AlN films were prepared on GaN/sapphire using a helicon sputtering system at the low temperature of 300 degrees C. Surface acoustic wave (SAW) devices fabricated on AlN/GaN/sapphire exhibited superior characteristics compared with those made on GaN/sapphire. An oscillator using an AlN/GaN/sapphirebased SAW device is presented. The oscillation frequency decreased when the device was illuminated by ultraviolet (UV) radiation, and the downshift of the oscillation frequency increased with the illuminating UV power density. The results showed that the AlN/GaN/sapphire-layered structure SAW oscillators are suitable for visible blind UV detection and opened up the feasibility of developing remote UV sensors for different ranges of wavelengths on the III-nitrides.

Solar ultraviolet-B radiation increases phenolic content and ferric reducing antioxidant power in Avena sativa.

PubMed

Ruhland, Christopher T; Fogal, Mitchell J; Buyarski, Christopher R; Krna, Matthew A

2007-06-29

We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm) on the maximum photochemical efficiency of photosystem II (F(v)/F(m)), bulk-soluble phenolic concentrations, ferric-reducing antioxidant power (FRAP) and growth of Avena sativa. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B by either 71% (reduced UV-B) or by 19% (near-ambient UV-B) over the 52 day experiment (04 July-25 August 2002). Plants growing under near-ambient UV-B had 38% less total biomass than those under reduced UV-B. The reduction in biomass was mainly the result of a 24% lower leaf elongation rate, resulting in shorter leaves and less total leaf area than plants under reduced UV-B. In addition, plants growing under near-ambient UV-B had up to 17% lower F(v)/F(m) values early in the experiment, and this effect declined with plant age. Concentrations of bulk-soluble phenolics and FRAP values were 17 and 24% higher under near-ambient UV-B than under reduced UV-B, respectively. There was a positive relationship between bulk-soluble phenolic concentrations and FRAP values. There were no UV-B effects on concentrations of carotenoids (carotenes + xanthophylls).

Changes in ultrastructure and responses of antioxidant systems of algae (Dunaliella salina) during acclimation to enhanced ultraviolet-B radiation.

PubMed

Tian, Jiyuan; Yu, Juan

2009-12-02

Because of depletion of the stratospheric ozone layer, levels of solar ultraviolet-B (UV-B) radiation (280-315 nm), which penetrates the water column to an ecologically-significant depth, are increasing. In order to assess changes in ultrastructure and responses of antioxidant systems of algae during acclimation to enhanced ultraviolet-B radiation, Dunaliella salina was treated with higher dose of UV-B radiation (13.2 kJm(-2) d(-1) dose) in this study. As compared to the control panel (8.8 kJm(-2) d(-1)), the treatment D. salina had many changes in ultrastructures: (1) thylakoids became swelled, and some of them penetrated into the pyrenoid; (2) lipid globules accumulated; (3) the amounts of starch grains increased; (4) cristae of mitochondria disintegrated; (5) inclusions in vacuoles reduced; and (6) cisternae of Golgi dictyosomes became loose and swollen. Enhanced UV-B irradiation also induced different responses of the antioxidant systems in D. salina: (1) contents of TBARS (thiobarbituric acid reacting substance) and H(2)O(2) increased significantly (p<0.05); (2) levels of MAAs (mycosporine-like amino acids) increased at the beginning and subsequently decreased, and finally they leveled off at lower values; (3) there were not apparent variations for carotenoid contents, and contents of chlorophyll a presented a trend of initial increase and ultimate decrease; (4) both ascorbate and glutathione contents increased significantly (p<0.05); and (5) for the enzyme activities, POD activities increased remarkably (p<0.05), and SOD activities declined apparently (p<0.05), and CAT activity in D. salina had slight variations (p>0.05). In addition, growth curve displayed that enhanced UV-B radiation prominently inhibited increase of cell concentration when compared with control panel (p<0.05). Our results indicated that enhanced UV-B radiation caused ultrastructural changes of D. salina and induced different responses of antioxidant systems in D. salina.

Physical and biological characterization of a seawater ultraviolet radiation sterilizer

NASA Astrophysics Data System (ADS)

Torrentera, Laura; Uribe, Roberto M.; Rodríguez, Romana R.; Carrillo, Ricardo E.

1994-03-01

The physical and biological characterization of a seawater ultraviolet (UV) sterilizer is described. The physical characterization was performed using radiochromic dye films by evaluating the uniformity of the radiant exposure along each lamp, the effect of the radiation from one lamp on the array of adjacent lamps, and by measuring the UV radiation absorption of seawater with respect to distilled water. The biological characterization was performed by measuring the amount of reduction of bacteria in stored seawater after different filtration and UV treatments. Among the filtration methods tested, differential filtration (5, 3 and 0.45 μm filters connected in series) caused the highest bacterial reduction factor of 60%. UV radiant exposures of 212, 424, 636 and 848 J m -2 yielded bacteria reduction factors of 99.86, 99.969, 99.997 and 100%, respectively, for populations of Vibrio and Pseudomonas bacteria present in stored seawater. It is concluded that the system is useful for water disinfection when 1, 2 or 3 lamps are on; when 4 lamps are used the treated water becomes sterile.

Intrinsic Lyα Profile Reconstructions of the MUSCLES Low-Mass Exoplanet Host Stars

NASA Astrophysics Data System (ADS)

Youngblood, Allison A.; France, Kevin; Loyd, R. O. Parke

2015-12-01

UV stellar radiation can significantly impact planetary atmospheres through heating and photochemistry, even regulating production of potential biomarkers. Cool stars emit the majority of their UV radiation in the form of emission lines, and the incident UV radiation on close-in habitable-zone planets is significant. Lyα (1215.67 Å) dominates the 912 - 3200 Å spectrum of cool stars, but strong absorption from the interstellar medium (ISM) makes direct observations of the intrinsic Lyα emission of even nearby stars challenging. The MUSCLES Hubble Space Telescope Treasury Survey (Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems) has completed observations of 7 M and 4 K stars hosting exoplanets (d < 22 pc). We have reconstructed the intrinsic Lyα profiles using an MCMC technique and used the results to estimate the extreme ultraviolet (100 - 911 Å) spectrum. We also present empirical relations between Lyα and chromospheric UV metal lines, e.g., Mg II, for use when ISM absorption prevents direct measurement of Lyα. The spectra presented here will be made publicly available through MAST to support exoplanet atmosphere modeling.

Photocatalytic reactive oxygen species production and phototoxicity of titanium dioxide nanoparticles are dependent on the solar ultraviolet radiation spectrum.

PubMed

Ma, Hongbo; Brennan, Amanda; Diamond, Stephen A

2012-09-01

Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO(2)) and its consequent phototoxicity to Daphnia magna were measured under different solar ultraviolet (UV) spectra by applying a series of optical filters in a solar simulator. Removing UV-B (280-320 nm) from solar radiation had no significant impact on photocatalytic ROS production of nano-TiO(2), whereas removal of UV-A (320-400 nm) decreased ROS production remarkably. Removal of wavelengths below 400 nm resulted in negligible ROS production. A linear correlation between ROS production and D. magna immobilization suggests that photocatalytic ROS production may be a predictor of phototoxicity for nano-TiO(2). Intracellular ROS production within D. magna was consistent with the immobilization of the organism under different solar UV spectra, indicating that oxidative stress was involved in phototoxicity. The dependence of nano-TiO(2) phototoxicity on environmentally realistic variations in solar radiation suggests that risk assessment of these nanomaterials requires careful evaluation of exposure conditions in the environment. Copyright © 2012 SETAC.

Association of amphibians with attenuation of ultraviolet-b radiation in montane ponds.

PubMed

Adams, Michael J; Schindler, Daniel E; Bury, Bruce R

2001-08-01

Ambient ultraviolet-b (UV-B) radiation (280-320 nm) has increased at north-temperate latitudes in the last two decades. UV-B can be detrimental to amphibians, and amphibians have shown declines in some areas during this same period. We documented the distribution of amphibians and salmonids in 42 remote, subalpine and alpine ponds in Olympic National Park, Washington, United States. We inferred relative exposure of amphibian habitats to UV-B by estimating the transmission of 305- and 320-nm radiation in pond water. We found breeding Ambystoma gracile, A. macrodactylum and Rana cascadae at 33%, 31%, and 45% of the study sites, respectively. Most R. cascadae bred in fishless shallow ponds with relatively low transmission of UV-B. The relationship with UV-B exposure remained marginally significant even after the presence of fish was included in the model. At 50 cm water depth, there was a 55% reduction in incident 305-nm radiation at sites where breeding populations of R. cascadae were detected compared to other sites. We did not detect associations between UV-B transmission and A. gracile or A. macrodactylum. Our field surveys do not provide evidence for decline of R. cascadae in Olympic National Park as has been documented in Northern California, but are consistent with the hypothesis that the spatial distribution of R. cascadae breeding sites is influenced by exposure to UV-B. Substrate or pond depth could also be related to the distribution of R. cascadae in Olympic National Park.

Association of amphibians with attenuation of ultraviolet-b radiation in montane ponds

USGS Publications Warehouse

Adams, Michael J.; Schindler, Daniel E.; Bury, R. Bruce

2001-01-01

Ambient ultraviolet-b (UV-B) radiation (280–320 nm) has increased at north-temperate latitudes in the last two decades. UV-B can be detrimental to amphibians, and amphibians have shown declines in some areas during this same period. We documented the distribution of amphibians and salmonids in 42 remote, subalpine and alpine ponds in Olympic National Park, Washington, United States. We inferred relative exposure of amphibian habitats to UV-B by estimating the transmission of 305- and 320-nm radiation in pond water. We found breeding Ambystoma gracile, A. macrodactylum and Rana cascadae at 33%, 31%, and 45% of the study sites, respectively. Most R. cascadae bred in fishless shallow ponds with relatively low transmission of UV-B. The relationship with UV-B exposure remained marginally significant even after the presence of fish was included in the model. At 50 cm water depth, there was a 55% reduction in incident 305-nm radiation at sites where breeding populations of R. cascadae were detected compared to other sites. We did not detect associations between UV-B transmission and A. gracile or A. macrodactylum. Our field surveys do not provide evidence for decline of R. cascadae in Olympic National Park as has been documented in Northern California, but are consistent with the hypothesis that the spatial distribution of R. cascadae breeding sites is influenced by exposure to UV-B. Substrate or pond depth could also be related to the distribution of R. cascadae in Olympic National Park.

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

ERIC Educational Resources Information Center

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

2015-01-01

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

Dry-season ultraviolet radiation primes litter for wet season decomposition in a Mediterranean grassland

NASA Astrophysics Data System (ADS)

Baker, N. R.; Allison, S. D.

2013-12-01

Traditional decomposition models developed in mesic ecosystems often consistently underestimate rates of decomposition in more arid ecosystems such as deserts and Mediterranean grasslands. Photodegradation of plant litter by ultraviolet radiation (UV) is hypothesized to be one of the mechanisms accounting for the greater-than-expected rates of decomposition observed in these ecosystems. Putatively, photodegradation preferentially degrades complex aromatic compounds in litter such as lignin, whose decomposition is considered a rate-limiting step in the microbial decomposition of plant litter. This study tested the effects of attenuated ultraviolet radiation on the decomposition of two litter types over the course of a year in a Southern California Mediterranean grassland. The two types of litter differed primarily in lignin content to test for a differential effect of UV on high-lignin versus low-lignin litter. Rates of litter mass loss, changes in litter chemistry, and changes in microbial activity and microbial biomass were observed, and assays of extracellular enzymes were conducted at 5 points through the year, beginning during the dry season and continuing until the end of the following dry season. Litter exposed to attenuated ultraviolet radiation during the dry season had lower rates of mass loss than litter exposed to ambient radiation (6.1% vs. 8.6%, respectively, p < 0.04). Extracellular enzyme activities were significantly affected by UV attenuation, as low lignin samples exposed to attenuated UV displayed elevated cellulase enzyme activity potential during the wet season, while high lignin samples displayed decreased oxidative enzyme activity potential during the wet season. For example, potential activity of the cellulase cellobiohydrolase in low-lignin, ambient UV samples was 5286 μmol/hr*g during the wet season, compared to 7969 μmol/hr*g in attenuated UV samples (p < 0.003). Conversely, potential activity of the oxidative enzyme peroxidase in high-lignin, ambient UV samples was 85.9 μmol/hr*g during the wet season, compared to 44.1 μmol/hr*g in attenuated UV samples (p < 0.028). This increased potential cellulase activity under attenuated UV may indicate that dry season photodegradation primes low-lignin litter for wet season decomposition, reducing the selective pressure for microbial decomposers to invest in costly extracellular enzyme production. Similarly, the reduced potential oxidative enzyme activity in high-lignin samples exposed to attenuated UV may indicate that photodegradation is necessary to facilitate the breakdown of more complex compounds such as lignin by microbial decomposers. We conclude that while abiotic factors such as photodegradation can have a significant effect on the mechanisms of plant matter decomposition in semiarid ecosystems, these effects are not only restricted to the dry season and may also facilitate wet season decomposition.

Ultraviolet germicidal efficacy as a function of pulsed radiation parameters studied by spore film dosimetry.

PubMed

Bauer, Stefan; Holtschmidt, Hans; Ott, Günter

2018-01-01

Disinfection by pulsed ultraviolet (UV) radiation is a commonly used method, e.g. in industry or medicine and can be carried out either with lasers or broadband UV radiation sources. Detrimental effects to biological materials depending on parameters such as pulse duration τ or pulse repetition frequency f p are well-understood for pulsed coherent UV radiation, however, relatively little is known for its incoherent variant. Therefore, within this work, it is the first time that disinfection rates of pulsed and continuous (cw) incoherent UV radiation studied by means of spore film dosimetry are presented, compared with each other, and in a second step further investigated regarding two pulse parameters. After analyzing the dynamic range of the Bacillus subtilis spore films with variable cw radiant exposures H=5-100Jm -2 a validation of the Bunsen-Roscoe law revealed its restricted applicability and a 28% enhanced detrimental effect of pulsed compared to cw incoherent UV radiation. A radiant exposure H=50Jm -2 and an irradiance E=0.5Wm -2 were found to be suitable parameters for an analysis of the disinfection rate as a function of τ=0.5-10ms and f p =25-500Hz unveiling that shorter pulses and lower frequencies inactivate more spores. Finally, the number of applied pulses as well as the experiment time were considered with regard to spore film disinfection. Copyright © 2017 Elsevier B.V. All rights reserved.

Combined effects of oil exposure, temperature and ultraviolet radiation on buoyancy and oxygen consumption of embryonic mahi-mahi, Coryphaena hippurus.

PubMed

Pasparakis, Christina; Sweet, Lauren E; Stieglitz, John D; Benetti, Daniel; Casente, Conrad T; Roberts, Aaron P; Grosell, Martin

2017-10-01

The Deepwater Horizon oil spill occurred in the summer of 2010 and coincided with the spawning window of the ecologically and economically important pelagic fish mahi-mahi (Coryphaena hippurus). During summer months, early life stage mahi-mahi were likely also exposed to other naturally occurring stressors such as increased temperature and ultraviolet radiation (UV). Previous research has shown that co-exposure to oil and additional natural stressors can affect the timing and duration of negative buoyancy in mahi-mahi embryos. The current study aimed to elucidate the factors affecting the onset of negative buoyancy and to also explore possible mechanisms behind buoyancy change. Embryos co-exposed to oil and/or increased temperature and UV radiation displayed early onset of negative buoyancy with concurrent increases in oxygen consumption and sinking rates, which are normally only seen during the period directly preceding hatch. Results also suggest a behavioral response in which embryos avoid UV radiation by sinking down the water column but reestablish positive buoyancy once the UV radiation is removed. These findings imply that embryos can dynamically change their position in the water column in response to external cues and thus may have much greater control over buoyancy than previously thought. Copyright © 2017 Elsevier B.V. All rights reserved.

[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.

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

EPA Science Inventory

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

Solar ultraviolet radiation from cancer induction to cancer prevention: solar ultraviolet radiation and cell biology.

PubMed

Tuorkey, Muobarak J

2015-09-01

Although decades have elapsed, researchers still debate the benefits and hazards of solar ultraviolet radiation (UVR) exposure. On the one hand, humans derive most of their serum 25-hydroxycholecalciferol [25(OH)D3], which has potent anticancer activity, from solar UVB radiation. On the other hand, people are more aware of the risk of cancer incidence associated with harmful levels of solar UVR from daily sunlight exposure. Epidemiological data strongly implicate UV radiation exposure as a major cause of melanoma and other cancers, as UVR promotes mutations in oncogenes and tumor-suppressor genes. This review highlights the impact of the different mutagenic effects of solar UVR, along with the cellular and carcinogenic challenges with respect to sun exposure.

The Effects of Ultraviolet Radiation on Attached Wetland Algae and Bacteria

NASA Astrophysics Data System (ADS)

Thomas, V. K.; Kuehn, K. A.; Francoeur, S. N.

2005-05-01

Despite the well-known increases in ultraviolet radiation (UV-R) reaching the Earth's surface due to the destruction of the ozone layer, little is known about effects of UV-R on wetland periphyton. To study the effects of UV-R on wetland periphyton, artificial substrata were placed under acrylic mesocosms in the Paint Creek Wetland, Ypsilanti, MI. One treatment mesocosm excluded light in the UV range (<340nm) and the other allowed the passage of full light. Periphyton attached to artificial substrata was collected on 4 dates during August and September 2004 and analyzed for Chlorophyll a, ash-free dry mass (AFDM), bacterial density, colloidal extracellular polysaccharides (EPS) and algal community composition. Over the length of the experiment the proportion of dead to live bacteria (p<0.02), EPS accrual (μgram glucose equivalents/cm2) (p=0.046), and the ratio of EPS to AFDM (p=0.027) were significantly greater in the UV-R-exposed treatment. These results suggest that ambient levels of UV-R damage periphytic bacteria and increase EPS production by periphyton.

Effect of ultraviolet radiation A and B on growth and mycotoxin production by Aspergillus carbonarius and Aspergillus parasiticus in grape and pistachio media.

PubMed

García-Cela, Esther; Marin, Sonia; Sanchis, Vicente; Crespo-Sempere, Ana; Ramos, Antonio J

2015-01-01

The effects of two exposure times per day (6 and 16 h) of UV-A or UV-B radiation, combined with dark and dark plus light incubation periods during 7-21 d on fungal growth and mycotoxins production of Aspergillus species were studied. Aspergillus carbonarius and Aspergillus parasiticus were inoculated on grape and pistachio media under diurnal and nocturnal temperatures choosing light photoperiod according to harvest conditions of these crops in Spain. Ultraviolet irradiation had a significant effect on A. carbonarius and A. parasiticus colony size (diameter, biomass dry weight, and colony density) and mycotoxin accumulation, although intraspecies differences were observed. Inhibition of A. carbonarius fungal growth decreased when exposure time was reduced from 16 h to 6 h, but this was not always true for ochratoxin A (OTA) production. OTA reduction was higher under UV-A than UV-B radiation and the reduction increased along time conversely to the aflatoxins (AFs). Aflatoxin B1 (AFB1) was the main toxin produced by A. parasiticus except in the UV-B light irradiated colonies which showed a higher percentage of AFG than AFB. Morphological changes were observed in colonies grown under UV-B light. Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

The MUSCLES Treasury Survey: Intrinsic Lyα Profile Reconstructions and UV, X-ray, and Optical Correlations of Low-mass Exoplanet Host Stars

NASA Astrophysics Data System (ADS)

Youngblood, Allison; France, Kevin; Loyd, R. O. Parke

2016-01-01

UV stellar radiation can significantly impact planetary atmospheres through heating and photochemistry, even regulating production of potential biomarkers. Cool stars emit the majority of their UV radiation in the form of emission lines, and the incident UV radiation on close-in habitable-zone planets is significant. Lyα (1215.67 Å) dominates the 912 - 3200 Å spectrum of cool stars, but strong absorption from the interstellar medium (ISM) makes direct observations of the intrinsic Lyα emission of even nearby stars challenging. The MUSCLES Hubble Space Telescope Treasury Survey (Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems) has completed observations of 7 M and 4 K stars hosting exoplanets (d < 22 pc) with simultaneous X-ray and ground-based optical spectroscopy for many of the targets. We have reconstructed the intrinsic Lyα profiles using an MCMC technique and used the results to estimate the extreme ultraviolet (100 - 911 Å) spectrum. We also present empirical relations between chromospheric UV and optical lines, e.g., Lyα, Mg II, Ca II H & K, and Hα, for use when direct UV observations of low-mass exoplanet host stars are not possible. The spectra presented here will be made publicly available through MAST to support exoplanet atmosphere modeling.

Molecular aspects of ultraviolet radiation-induced apoptosis in the skin.

PubMed

Chow, Jeffrey; Tron, Victor A

2005-12-01

Apoptosis, or programmed cell death, is an essential physiological process that controls cell numbers during physiological processes, and eliminates abnormal cells that can potentially harm an organism. This review summarizes our current state of knowledge of apoptosis induction in skin by UV radiation. A review of the literature was undertaken focusing on cell death in the skin secondary to UV radiation. It is evident that a number of apoptotic pathways, both intrinsic and extrinsic, are induced following exposure to damaging UV radiation. Although our understanding of the apoptotic processes is gradually increasing, many important aspects remain obscure. These include interconnections between pathways, wavelength-specific differences and cell type differences.

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

Ultraviolet absorption by highly ionized halo gas near the Galactic center

NASA Technical Reports Server (NTRS)

Savage, B. D.; Massa, D.

1985-01-01

Initial results are presented for a program to survey highly ionized gas in the Milky Way disk and halo. High-resolution IUE (International Ultraviolet Explorer) far-UV spectra were obtained for 12 stars at galactocentric distances less than 6 kpc. The stars are 0.7-2.2 kpc away from the plane. Most of the spectra contain exceedingly strong and broad interstellar absorption lines of weakly and highly ionized atoms. In addition to the normally strong lines of Si IV and C IV, strong interstellar NV lines have been detected in the spectra of eight stars. The detection of NV absorption (amounting to more than 10 times the predicted NV) provides an important new constraint on models for the origin of Galactic halo gas. A Galactic fountain operating in the presence of known UV and EUV radiation might explain the observations.

Ultraviolet B radiation induces impaired lifecycle traits and modulates expression of cytochrome P450 (CYP) genes in the copepod Tigriopus japonicus.

PubMed

Puthumana, Jayesh; Lee, Min-Chul; Park, Jun Chul; Kim, Hui-Su; Hwang, Dae-Sik; Han, Jeonghoon; Lee, Jae-Seong

2017-03-01

To evaluate the effects of ultraviolet B (UV-B) radiation at the developmental, reproductive, and molecular levels in aquatic invertebrates, we measured UV-B-induced acute toxicity, impairments in developmental and reproductive traits, and UV-B interaction with the entire family of cytochrome P450 (CYP) genes in the intertidal benthic copepod Tigriopus japonicus. We found a significant, dose-dependent reduction (P<0.05) in the survival of T. japonicus that began as a developmental delay and decreased fecundity. The 48h LD10 and LD50 were 1.35 and 1.84kJ/m 2 , and the CYP inhibitor (PBO) elevated mortality, confirming the involvement of CYP genes in UV-B induced toxicity. Low-dose UV-B (1.5kJ/m 2 ) induced developmental delays, and higher doses (6-18kJ/m 2 ) caused reproductive impairments in ovigerous females. The significant up-regulation of CYP genes belonging to clans 2/3/MT/4/20 in T. japonicus exposed to UV-B (12kJ/m 2 ) confirmed molecular interaction between UV-B and CYP genes. Moreover, orphan CYPs, such as CYP20A1, provide good insight on the deorphanization of invertebrate CYPs. Overall, these results demonstrate the involvement of UV-B radiation in the expression of all the CYP genes in T. japonicus and their susceptibility to UV-B radiation. This will provide a better understanding of the mechanistic effects of UV-B in copepods through the predicted AhR-mediated up-regulation of CYP genes. Copyright © 2017 Elsevier B.V. All rights reserved.

Fruit and vegetable extracts as radiation protectants for the beet armyworm nucleopolyhedrovirus

USDA-ARS?s Scientific Manuscript database

Extracts from 37 fruits and vegetables were tested as ultraviolet (UV) protectants for the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Only one extract (black currant) provided almost complete protection following ultraviolet B/ultraviole...

Pregnancy outcome and ultraviolet radiation; A systematic review

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

Megaw, Lauren, E-mail: lauren.megaw@ed.ac.uk

Background: Season and vitamin D are indirect and direct correlates of ultraviolet (UV) radiation and are associated with pregnancy outcomes. Further to producing vitamin D, UV has positive effects on cardiovascular and immune health that may support a role for UV directly benefitting pregnancy. Objectives: To investigate the effects of UV exposure on pregnancy; specifically fetal growth, preterm birth and hypertensive complications. Methods: We conducted a systematic review of Medline, EMBASE, DoPHER, Global Health, ProQuest Public Health, AustHealth Informit, SCOPUS and Google Scholar to identify 537 citations, 8 of which are included in this review. This review was registered onmore » PROSPERO and a. narrative synthesis is presented following PRISMA guidance. Results: All studies were observational and assessed at high risk of bias. Higher first trimester UV was associated with and improved fetal growth and increased hypertension in pregnancy. Interpretation is limited by study design and quality. Meta-analysis was precluded by the variety of outcomes and methods. Discussion: The low number of studies and risk of bias limit the validity of any conclusions. Environmental health methodological issues are discussed with consideration given to design and analytical improvements to further address this reproductive environmental health question. Conclusions: The evidence for UV having benefits for pregnancy hypertension and fetal growth is limited by the methodological approaches utilized. Future epidemiological efforts should focus on improving the methods of modeling and linking widely available environmental data to reproductive health outcomes. - Highlights: • Biologically plausible pathways support an association between ultraviolet radiation (UV) and pregnancy outcomes. • This study is the first systematic review of prevailing literature on the relationship between UV and singleton pregnancy outcomes. • It focuses on both substantive findings and the methodologies that were used. • Only seven studies met the search criteria and these were methodologically heterogeneous demonstrating a paucity of evidence. • Given the plausibility of the UV pathway, more studies examining this hypothesis are needed.« less

Formation of buckminsterfullerene (C60) in interstellar space

PubMed Central

Berné, Olivier; Tielens, A. G. G. M.

2012-01-01

Buckminsterfullerene (C60) was recently confirmed as the largest molecule identified in space. However, it remains unclear how and where this molecule is formed. It is generally believed that C60 is formed from the buildup of small carbonaceous compounds in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C60 is efficiently formed in the tenuous and cold environment of an interstellar cloud illuminated by strong ultraviolet (UV) radiation fields. This implies that another formation pathway, efficient at low densities, must exist. Based on recent laboratory and theoretical studies, we argue that polycyclic aromatic hydrocarbons are converted into graphene, and subsequently C60, under UV irradiation from massive stars. This shows that alternative—top-down—routes are key to understanding the organic inventory in space. PMID:22198841

Formation of buckminsterfullerene (C60) in interstellar space.

PubMed

Berné, Olivier; Tielens, A G G M

2012-01-10

Buckminsterfullerene (C(60)) was recently confirmed as the largest molecule identified in space. However, it remains unclear how and where this molecule is formed. It is generally believed that C(60) is formed from the buildup of small carbonaceous compounds in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C(60) is efficiently formed in the tenuous and cold environment of an interstellar cloud illuminated by strong ultraviolet (UV) radiation fields. This implies that another formation pathway, efficient at low densities, must exist. Based on recent laboratory and theoretical studies, we argue that polycyclic aromatic hydrocarbons are converted into graphene, and subsequently C(60), under UV irradiation from massive stars. This shows that alternative--top-down--routes are key to understanding the organic inventory in space.

Formation of buckminsterfullerene (C60) in interstellar space

NASA Astrophysics Data System (ADS)

Berné, Olivier; Tielens, Alexander G. G. M.

2012-01-01

Buckminsterfullerene (C60) was recently confirmed to be the largest molecule identified in space. However, it remains unclear how, and where this molecule is formed. It is generally believed that C60 is formed from the build up of small carbonaceous compounds, in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C60 is efficiently formed in the tenuous and cold environment of an interstellar cloud illuminated by strong ultraviolet (UV) radiation fields. This implies that another formation pathway, efficient at low densities, must exist. Based on recent laboratory and theoretical studies, we argue that Polycyclic Aromatic Hydrocarbons are converted into graphene, and subsequently C60, under UV irradiation from massive stars. This shows that alternative - top-down - routes are key to understanding the organic inventory in space.

Effectiveness of automated ultraviolet-C light for decontamination of textiles inoculated with Enterococcus faecium.

PubMed

Smolle, C; Huss, F; Lindblad, M; Reischies, F; Tano, E

2018-01-01

Healthcare textiles are increasingly recognized as potential vehicles for transmission of hospital-acquired infections. This study tested the ability of an automated ultraviolet-C (UV-C) room disinfection device (Tru-D Smart UV-C) to decontaminate textiles inoculated with Enterococcus faecium in a clinical setting. Contaminated polycotton (50/50 polyester/cotton) swatches were distributed to predefined locations in a ward room and exposed to UV-C light. UV-C decontamination reduced E. faecium counts by a mean log 10 reduction factor of 1.37 (all P = 0.005, Wilcoxon signed rank test). UV-C decontamination may be a feasible adjunctive measure to conventional laundering to preserve the cleanliness of healthcare textiles in ward rooms. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Influence of altitude and enhanced ultraviolet-B radiation on tuber production, seed viability, leaf pigments and morphology in the wild potato species Solanum kurtzianum Bitter & Wittm collected from an elevational gradient.

PubMed

Ibañez, V N; Berli, F J; Masuelli, R W; Bottini, R A; Marfil, C F

2017-08-01

Climate change could lead to an upward shift in plant distribution, exposing populations to higher levels of ultraviolet (UV)-B radiation. In the framework of an in situ strategy for conserving potato wild relatives, we evaluated the effect of high UV-B levels on natural population of Solanum kurtzianum. The hypothesis is that plants from naturally higher altitudes are more adapted to increased UV-B radiation. Two populations from low and high altitudes were field supplemented using UV-B-lamps (+UV-B) or excluded from it with plastic filters. Additionally, to assess in which extent the plant responses to these artificial experimental conditions are reproducible in natural conditions, three genotypes were cultivated in two mountain experimental gardens (EG) at different elevations. +UV-B treatment induced changes in leaf morphology and increases in phenolic compounds in both populations, indicating plant adaptation, since chlorophylls and reproductive structures were not negatively affected. These results indicate that this environmental factor may not limit the displacement of populations towards sites with higher UV-B levels. Meanwhile, in higher-altitude EG a tubers yield reduction, mainly through a decreased tuber number and a bigger accumulation of phenolic compounds than in +UV-B treatment were observed, suggesting that UV-B is not the only factor involved in plants adaptation to high altitude environments. Copyright © 2017. Published by Elsevier B.V.

Melting-solidification transition of Zn nanoparticles embedded in SiO2: Observation by synchrotron x-ray and ultraviolet-visible-near-infrared light

NASA Astrophysics Data System (ADS)

Amekura, H.; Tanaka, M.; Katsuya, Y.; Yoshikawa, H.; Ohnuma, M.; Matsushita, Y.; Kobayashi, K.; Kishimoto, N.

2010-11-01

Melting-solidification transition of Zn nanoparticles (NPs) with the mean diameter of 11.5 nm, embedded in silica glass, was investigated by glancing incident x-ray diffraction (GIXRD) at high temperatures using synchrotron radiation (SR). With increasing temperature, 101Zn diffraction peak gradually decreases up to ˜360 °C and then steeply decreases. This is due to the melting of Zn NPs, which completes around 420 °C. With decreasing temperature, the solidification of the NPs begins around ˜310 °C. The temperature hysteresis with a width of ˜110 °C was observed. With temperature, the diffraction angle shows a shift without hysteresis, which is ascribed to thermal expansion of Zn NP lattice. Thermal expansion coefficient of Zn NPs was determined as 24.4×10-6 K-1 along the ⟨101⟩ direction. Optical absorption spectroscopy shows a broad ultraviolet (UV) peak which was observed at even higher temperatures than the melting temperature but shifts to the low-energy side with the melting. The energy shift in the UV peak also shows the temperature hysteresis which resembles with the melting-solidification hysteresis recorded by SR-GIXRD. The melting-solidification transition is also detectable by the optical absorption spectroscopy in the UV-visible-near-infrared region.

Next-Generation Fire Extinguishing Agent. Phase 4. Foundation for New Training Agent Development

DTIC Science & Technology

1989-12-01

Administration PCE perchloroethylene PEL Permissible Exposure Limit QSAR Quantitative Structure Activity Relationship SBUV Solar Backscatter Ultraviolet xi...can pass through the troposphere without destruction to enter the stratosphere. In the stratosphere, they photolyze in the intense solar radiation to...radiation, UV-B, striking the earth. Preliminary data from a Solar Backscatter Ultraviolet (SBUV) instrument aboard NASA’s Nimbus 7 satellite show a

UV emissions from artificial tanning devices and their compliance with the European technical standard.

PubMed

Facta, Stefania; Fusette, Stefania Saudino; Bonino, Alessandro; Anglesio, Laura; d'Amore, Giovanni

2013-04-01

Use of ultraviolet radiation-emitting tanning devices has been classified as "carcinogenic to humans" (group 1) by the International Agency for Research on Cancer. Following this classification, the knowledge of typical ultraviolet emission levels from tanning devices can be of interest for evaluating their impact on health. In this work, the results of an extensive measurement campaign on artificial tanning appliances are presented. Ultraviolet emissions from 94 tanning appliances produced by 15 different manufacturers were characterized by onsite spectroradiometric measurements. The measured radiometric quantities were compared with reference values fixed in the European technical standard EN 60335-2-27 "Household and similar electrical appliances-Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation." Measurement results indicate that 88% of the examined appliances had ultraviolet emissions not compliant with the technical standard. Among the considered appliances, tanning devices equipped with low pressure lamps showed higher ultraviolet levels of effective irradiance and less compliance with standard requirements. In particular, UV emissions from 100% of low pressure appliances and from 78% of high pressure appliances exceeded the irradiance limit of 0.3 Wm set by the European technical standard.

Comparison of UV Protection Properties of Cotton Fabrics Treated with Aqueous and Methanolic Extracts of Achyranthes aspera and Alhagi maurorum Plants.

PubMed

Nazir, Ahsan; Saleem, Muhammad Asad; Nazir, Faiza; Hussain, Tanveer; Faizan, Muhammad Qasim; Usman, Muhammad

2016-03-01

UV radiations are high-energy radiations present in sunlight that can damage human skin. Protection against these radiations becomes vital especially in those areas of the globe where UV index is quite high that makes the inhabitants more prone to dangerous effects of UV radiations. Clothing materials are good blockers of UV radiations, particularly when the fabric cover factor is high and/or the fabrics contain suitable UV-blocking finishes. In this study, effect of application of aqueous and methanolic extracts of two different plants, i.e., Achyranthes aspera and Alhagi maurorum on UV protection properties of cotton fabric was investigated. The results showed that the fabric samples treated with extracts of both the plants have excellent UV protection properties as indicated by their ultraviolet protection factor. It was concluded that both the aqueous and methanolic plant extracts are very effective in blocking UVA and UVB radiations, when applied on cotton fabrics. The UV protection performance of Achyranthes aspera extracts was much better as compared to that of Alhagi maurorum, and methanolic extracts of both the plants outperformed the aqueous extracts in terms of UV protection. © 2016 The American Society of Photobiology.

Ultraviolet disinfection of potable water

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

Wolfe, R.L.

Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as wellmore » as the advantages and disadvantages of UV disinfection. 38 refs.« less

Photodegradation of the antimicrobial triclocarban in aqueous systems under ultraviolet radiation.

PubMed

Ding, Shi-Ling; Wang, Xi-Kui; Jiang, Wen-Qiang; Meng, Xia; Zhao, Ru-Song; Wang, Chen; Wang, Xia

2013-05-01

This work aimed to investigate the effectiveness of ultraviolet (UV) radiation on the degradation of the antimicrobial triclocarban (TCC). We investigated the effects of several operational parameters, including solution pH, initial TCC concentration, photocatalyst TiO₂ loading, presence of natural organic matter, and most common anions in surface waters (e.g., bicarbonate, nitrate, and sulfate). The results showed that UV radiation was very effective for TCC photodegradation and that the photolysis followed pseudo-first-order kinetics. The TCC photolysis rate was pH dependent and favored at high pH. A higher TCC photolysis rate was observed by direct photolysis than TiO₂ photocatalysis. The presence of the inorganic ions bicarbonate, nitrate, and sulfate hindered TCC photolysis. Negative effects on TCC photolysis were also observed by the addition of humic acid due to competitive UV absorbance. The main degradation products of TCC were tentatively identified by gas chromatograph with mass spectrometer, and a possible degradation pathway of TCC was also proposed.

EFFECTS OF SUSPENDED SEDIMENTS ON PHOTOLYSIS RATES OF DISSOLVED POLLUTANTS

EPA Science Inventory

Data are presented concerning the effects of suspended sediments upon photolysis rates of dissolved ultraviolet (u.v.) absorbing pollutants. The malachite green leucocyanide actinometer was found to be a convenient and sensitive device for measurement of solar u.v. radiation (abo...

Is UV-induced DNA damage greater at higher elevation?

PubMed

Wang, Qing-Wei; Hidema, Jun; Hikosaka, Kouki

2014-05-01

• Although ultraviolet radiation (UV) is known to have negative effects on plant growth, there has been no direct evidence that plants growing at higher elevations are more severely affected by ultraviolet-B (UV-B) radiation, which is known to increase with elevation. We examined damage to DNA, a primary target of UV-B, in the widespread species Polygonum sachalinense (Fallopia sachalinensis) and Plantago asiatica at two elevations.• We sampled leaves of both species at 300 and 1700 m above sea level every 2 h for 11 d across the growing season and determined the level of cyclobutane pyrimidine dimer (CPD), a major product of UV damage to DNA.• The CPD level was significantly influenced by the time of day, date, elevation, and their interactions in both species. The CPD level tended to be higher at noon or on sunny days. DNA damage was more severe at 1700 m than at 300 m: on average, 8.7% greater at high elevation in P. asiatica and 7.8% greater in P. sachalinense Stepwise multiple regression analysis indicated that the CPD level was explained mainly by UV-B and had no significant relationship with other environmental factors such as temperature and photosynthetically active radiation.• UV-induced DNA damage in plants is greater at higher elevations. © 2014 Botanical Society of America, Inc.

A look into the invisible: ultraviolet-B sensitivity in an insect (Caliothrips phaseoli) revealed through a behavioural action spectrum

PubMed Central

Mazza, Carlos A.; Izaguirre, Miriam M.; Curiale, Javier; Ballaré, Carlos L.

2010-01-01

Caliothrips phaseoli, a phytophagous insect, detects and responds to solar ultraviolet-B radiation (UV-B; λ ≤ 315 nm) under field conditions. A highly specific mechanism must be present in the thrips visual system in order to detect this narrow band of solar radiation, which is at least 30 times less abundant than the UV-A (315–400 nm), to which many insects are sensitive. We constructed an action spectrum of thrips responses to light by studying their behavioural reactions to monochromatic irradiation under confinement conditions. Thrips were maximally sensitive to wavelengths between 290 and 330 nm; human-visible wavelengths (λ ≥ 400 nm) failed to elicit any response. All but six ommatidia of the thrips compound eye were highly fluorescent when exposed to UV-A of wavelengths longer than 330 nm. We hypothesized that the fluorescent compound acts as an internal filter, preventing radiation with λ > 330 nm from reaching the photoreceptor cells. Calculations based on the putative filter transmittance and a visual pigment template of λmax = 360 nm produced a sensitivity spectrum that was strikingly similar to the action spectrum of UV-induced behavioural response. These results suggest that specific UV-B vision in thrips is achieved by a standard UV-A photoreceptor and a sharp cut-off internal filter that blocks longer UV wavelengths in the majority of the ommatidia. PMID:19846453

Tolerance of entomopathogenic fungi to ultraviolet radiation: a review on screening of strains and their formulation.

PubMed

Fernandes, Éverton K K; Rangel, Drauzio E N; Braga, Gilberto U L; Roberts, Donald W

2015-08-01

Ultraviolet radiation from sunlight is probably the most detrimental environmental factor affecting the viability of entomopathogenic fungi applied to solar-exposed sites (e.g., leaves) for pest control. Most entomopathogenic fungi are sensitive to UV radiation, but there is great inter- and intraspecies variability in susceptibility to UV. This variability may reflect natural adaptations of isolates to their different environmental conditions. Selecting strains with outstanding natural tolerance to UV is considered as an important step to identify promising biological control agents. However, reports on tolerance among the isolates used to date must be analyzed carefully due to considerable variations in the methods used to garner the data. The current review presents tables listing many studies in which different methods were applied to check natural and enhanced tolerance to UV stress of numerous entomopathogenic fungi, including several well-known isolates of these fungi. The assessment of UV tolerance is usually conducted with conidia using dose-response methods, wherein the UV dose is calculated simply by multiplying the total irradiance by the period (time) of exposure. Although irradiation from lamps seldom presents an environmentally realistic spectral distribution, laboratory tests circumvent the uncontrollable circumstances associated with field assays. Most attempts to increase field persistence of microbial agents have included formulating conidia with UV protectants; however, in many cases, field efficacy of formulated fungi is still not fully adequate for dependable pest control.

Inconstant sun: how solar evolution has affected cosmic and ultraviolet radiation exposure over the history of life on Earth.

PubMed

Karam, P Andrew

2003-03-01

Four billion years ago, sea-level UV exposure was more than 400 times as intense as today, the dose from solar cosmic rays was five times present levels, and galactic cosmic rays accounted for only about 10% their current contribution to sea-level radiation doses. Exposure to cosmic radiation accounts for about 10% of natural background radiation exposure today and includes dose from galactic cosmic rays and solar charged particles. There is little exposure to ionizing wavelengths of UV due to absorption by ozone. The sun has evolved significantly over its life; in the past there were higher levels of particulate radiation and lower UV emissions from the sun, and a stronger solar wind reduced radiation dose in the inner solar system from galactic cosmic rays. Finally, since the early atmosphere contained little to no oxygen, surface levels of UV radiation were far higher in the past.

[Impact of the women's press on the attitudes of readers toward ultraviolet radiation--a survey of law and psychology students].

PubMed

Gałajda, Karolina; Kamińska-Winciorek, Grazyna; Spiewak, Radosław

2013-08-01

Excessive exposure to ultraviolet radiation (UVA and UVB) leads to negative consequences including sunburn, carcinogenesis and photoaging. Therefore, educational campaigns promoting safe tanning and sunscreens are necessary. Helpful with this regard might be mass media including women's magazines, which for young people are important source of information on health, beauty and lifestyle. The aim of the study was to examine the influence of women's press in the attitude of non-medical students toward ultraviolet radiation (UV) as well as to analyse articles about tanning and skin protection against UV rays in selected magazines for women. The study group consisted of 68 psychology students and 60 law students (n = 128). An original author's questionnaire was used in this research, including 22 questions regarding frequency of reading articles about sunbathing, and the impact of women's press on the respondents' attitude toward suntanning. In the second part of the study 13 articles were examined from magazines "Twój Styl", "ELLE", "PANI" (years 2007-2011), which contained keywords "sun", "tanning bed", "tanning", "UV radiation". Selected articles were assessed whether they were encouraging to, or discouraging from sunbathing. A majority (63%) of respondents declared that after reading the article in women's magazines, they began to apply a sunscreen with higher SPF rate than before. Moreover, 57% refrained from using tanbeds, and 48% began to regularly check melanocytic naevi and monitor their skin after sun exposures. The analysis of the articles showed that majority of articles discouraged from the sunbathing (11 articles discouraging versus and 2 encouraging). Women's press in Poland generally promotes women's rational behavior against UV radiation and tanning.

Silymarin Protects Epidermal Keratinocytes from Ultraviolet Radiation-Induced Apoptosis and DNA Damage by Nucleotide Excision Repair Mechanism

PubMed Central

Katiyar, Santosh K.; Mantena, Sudheer K.; Meeran, Syed M.

2011-01-01

Solar ultraviolet (UV) radiation is a well recognized epidemiologic risk factor for melanoma and non-melanoma skin cancers. This observation has been linked to the accumulation of UVB radiation-induced DNA lesions in cells, and that finally lead to the development of skin cancers. Earlier, we have shown that topical treatment of skin with silymarin, a plant flavanoid from milk thistle (Silybum marianum), inhibits photocarcinogenesis in mice; however it is less understood whether chemopreventive effect of silymarin is mediated through the repair of DNA lesions in skin cells and that protect the cells from apoptosis. Here, we show that treatment of normal human epidermal keratinocytes (NHEK) with silymarin blocks UVB-induced apoptosis of NHEK in vitro. Silymarin reduces the amount of UVB radiation-induced DNA damage as demonstrated by reduced amounts of cyclobutane pyrimidine dimers (CPDs) and as measured by comet assay, and that ultimately may lead to reduced apoptosis of NHEK. The reduction of UV radiation-induced DNA damage by silymarin appears to be related with induction of nucleotide excision repair (NER) genes, because UV radiation-induced apoptosis was not blocked by silymarin in NER-deficient human fibroblasts. Cytostaining and dot-blot analysis revealed that silymarin repaired UV-induced CPDs in NER-proficient fibroblasts from a healthy individual but did not repair UV-induced CPD-positive cells in NER-deficient fibroblasts from patients suffering from xeroderma pigmentosum complementation-A disease. Similarly, immunohistochemical analysis revealed that silymarin did not reduce the number of UVB-induced sunburn/apoptotic cells in the skin of NER-deficient mice, but reduced the number of sunburn cells in their wild-type counterparts. Together, these results suggest that silymarin exert the capacity to reduce UV radiation-induced DNA damage and, thus, prevent the harmful effects of UV radiation on the genomic stability of epidermal cells. PMID:21731736

Ultraviolet radiation as an ant repellent

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

Thorvilson, H.G.; Russell, S.A.; Green, B.

1996-12-31

In an effort to repel red imported fire ants (RIFA) from electrical devices, such as transformers, ultraviolet (UV) light was tested. Initial tests determined if RIFA`s tolerate a UV-irradiated environment when given a choice between UV-irradiated and non-irradiated. All replications in this test indicated that RIFA`s are intolerant of UV-irradiation and sought to escape it. RIFA`s moved to shaded environments and transported their brood out its well. A second test sought to determine if long-term UV-irradiation of the entire colonies cause increased RIFA mortality. Queenright colonies were exposed to UV irradiation of 254nm constantly for 115 days and colonies hadmore » a higher mortality rate than did a control colony. RIFA`s attempted to escape UV light and had increased rate when exposed to UV (254nm), but a practical application of this technique may be detrimental to insulation on electrical wiring.« less

THE EFFECT OF RADIATION ON ACETABULARIA. III. THE EFFECT OF X RADIATION AND ULTRAVIOLET RADIATION ON THE NUCLEATED PART OF ACETABULARIA MEDITERRANEA (in German)

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

Six, E.

1958-01-01

A study was made of the effect of x rays and ultraviolet radiation of various wave lengths on the nucleated cell part of Acetabularia mediterranea. The x radintion leads to a reduction of the regenerative capacity, to a decrease of cyst formation of the regenerated cells, and to a lowering of the viability of the cysts. After a dose of 400 hr the regenerative capacity is almost completely destroyed. The capacity for the formation of reproductive gametes is lost after 40 hr. The effect of UV irradiation is, on the other hand, much less. It was concluded that the observedmore » functions of the nucleated cell part are essentially determined by the nucleus, which in rhizoids is extensively shielded against UV radiation. A complete regeneration up to cap formation follows so size and shape of the full-grown regenerated cells do not appear to be influenced essertially by x radiation. (tr-auth)« less

Invisible Misconceptions: Student Understanding of Ultraviolet and Infrared Radiation

ERIC Educational Resources Information Center

Libarkin, Julie C.; Asghar, Anila; Crockett, C.; Sadler, Philip

2011-01-01

The importance of nonvisible wavelengths for the study of astronomy suggests that student understanding of nonvisible light is an important consideration in astronomy classrooms. Questionnaires, interviews, and panel discussions were used to investigate 6-12 student and teacher conceptions of ultraviolet (UV) and infrared (IR). Alternative…

Determination of ultraviolet filter activity on coconut oil cosmetic cream

NASA Astrophysics Data System (ADS)

Widiyati, Eni

2017-08-01

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

Plant response to solar ultraviolet radiation

NASA Technical Reports Server (NTRS)

Caldwell, M. M.

1981-01-01

Plant reactions and mechanisms of reaction to solar UV radiation are reviewed, along with characteristics of plants which enhance UV tolerance. Wavelength regions to which proteins are particularly sensitive are examined and the possibility of synergistic effects from photoreactions to multiple wavelengths is considered, along with available evidence of nonadditive plant spectral responses to UV radiation. Decreases in atmospheric ozone content are explored in terms of UV wavelengths which would increase with the ozone decreases, particularly for UV-B, which depresses photosynthesis and would increase 1% with a 16% reduction of stratospheric ozone. Higher elevations are projected to display effects of increased UV incident flux first, and global distributions of UV increases due to atmospheric inhomogeneity and water surface clarity are examined. Finally, the response of plant nucleic acids, DNA, chlorophyll to enhanced UV are described, along with repair, avoidance, and optical mechanisms which aid plant survival

Association of UV Index and Sunscreen Use among White High School Students in the United States

ERIC Educational Resources Information Center

Everett Jones, Sherry; O'Malley Olsen, Emily; Michael, Shannon L.; Saraiya, Mona

2013-01-01

Background: When used appropriately, sunscreen decreases the amount of ultraviolet (UV) radiation exposure to the skin and is recommended to prevent skin cancer. This study examined the association between annual average UV index and sunscreen use among White, non-Hispanic youth. Methods: The 2007 and 2009 national Youth Risk Behavior Survey…

Estimation of pedestrian level UV exposure under trees

Treesearch

Richard H. Grant; Gordon M. Heisler; Wei Gao

2002-01-01

Trees influence the amount of solar UV radiation that reaches pedestrians. A three-dimensional model was developed to predict the ultraviolet-B (UV-B) irradiance fields in open-tree canopies where the spacing between trees is equal to or greater than the width of individual tree crowns. The model predicted the relative irradiance (fraction of above-canopy irradiance)...

The effects of nutrient solution sterilization on the growth and yield of hydroponically grown lettuce

NASA Technical Reports Server (NTRS)

Schwartzkopf, S. H.; Dudzinski, D.; Minners, R. S.

1987-01-01

Two methods of removing bacteria from hydroponic nutrient solution [ultraviolet (UV) radiation and submicronic filter] were evaluated for efficiency and for their effects on lettuce (Lactuca sativa L.) production. Both methods were effective in removing bacteria; but, at high intensity, the ultraviolet sterilizer significantly inhibited the production of plants grown in the treated solution. Bacterial removal by lower intensity UV or a submicronic filter seemed to promote plant growth slightly, but showed no consistent, statistically significant effect.

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

PubMed

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

2018-01-01

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

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

PubMed Central

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

2018-01-01

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

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.

The effect of ultraviolet radiation on the cornea - experimental study.

PubMed

Golu, Andreea; Gheorghişor, Irina; Bălăşoiu, A T; Baltă, Fl; Osiac, E; Mogoantă, L; Bold, Adriana

2013-01-01

Ultraviolet (UV) radiation in high doses may have harmful effects on the eye. The sources of UV radiation are the sun, as well as some artificial sources such as UV lamps or voltaic arcs. Chronic exposure to UV can cause damage to the anterior pole of the eye, ranging from minor (pterygium) to serious photokeratitis. In our study, we applied a UV dose of 6.5 J/cm(2) in the wavelength range of 290-400 nm, for five consecutive days per rat anterior pole of the eye. Seven days after the last dose of radiation, the animals were sacrificed, harvesting both the irradiated and the non-irradiated eye. Histological and immunohistochemical examination of the lesions revealed that the greatest damage to the epithelium was recorded prior to and 2/3 of the remaining corneal stroma. The epithelial lesions we found varied from pseudokeratosis and detachment of the Bowman epithelium membrane to deep epithelial necrosis. Within the corneal stroma, we observed the formation of interstitial edema with disruption of the collagen structure. We also noticed the presence of an inflammatory infiltrate composed mainly of lymphocytes and CD68+ and CD163+ macrophages, as well as the occurrence of vascular devices. These consisted of angiogenesis capillaries with structured wall composed mainly of endothelial CD34+ precursor cells and a basal membrane rich in collagen IV fibers.

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 phytoplankton will be exposed to solar ultraviolet radiation. This radiation has been shown to affect growth, photosynthesis, nitrogen incorporation and enzyme activity. Other targets of solar UV irradiation are proteins and pigments involved in photosynthesis. Whether or not screening pigments can be induced in phytoplankton to effectively shield the organisms from excessive UV irradiation needs to be determined. Macroalgae show a distinct pattern of vertical distribution in their habitat. They have developed mechanisms to regulate their photosynthetic activity to adapt to the changing light regime and protect themselves from excessive radiation. A broad survey was carried out to understand photosynthesis in aquatic ecosystems and the different adaptation strategies to solar radiation of ecologically important species of green, red and brown algae from the North Sea, Baltic Sea, Mediterranean, Atlantic, polar and tropical oceans. Photoinhibition was quantified by oxygen exchange and by PAM (pulse amplitude modulated) fluorescence measurements based on transient changes of chlorophyll fluorescence. c2001 COSPAR Published by Elsevier Science Ltd. All rights reserved.

Ultraviolet-B radiation modifies the quantitative and qualitative profile of flavonoids and amino acids in grape berries.

PubMed

Martínez-Lüscher, J; Torres, N; Hilbert, G; Richard, T; Sánchez-Díaz, M; Delrot, S; Aguirreolea, J; Pascual, I; Gomès, E

2014-06-01

Grapevine cv. Tempranillo fruit-bearing cuttings were exposed to supplemental ultraviolet-B (UV-B) radiation under controlled conditions, in order to study its effect on grape traits, ripening, amino acids and flavonoid profile. The plants were exposed to two doses of UV-B biologically effective (5.98 and 9.66kJm(-2)d(-1)), applied either from fruit set to ripeness or from the onset of veraison to ripeness. A 0kJm(-2)d(-1) treatment was included as a control. UV-B did not significantly modify grape berry size, but increased the relative mass of berry skin. Time to reach ripeness was not affected by UV-B, which may explain the lack of changes in technological maturity. The concentration of must extractable anthocyanins, colour density and skin flavonols were enhanced by UV-B, especially in plants exposed from fruit set. The quantitative and qualitative profile of grape skin flavonols were modified by UV-B radiation. Monosubstituted flavonols relative abundance increased proportionally to the accumulated UV-B doses. Furthermore, trisubstituted forms, which where predominant in non-exposed berries, were less abundant as UV-B exposure increased. Although total free amino acid content remained unaffected by the treatments, the increased levels of gamma-aminobutyric acid (GABA), as well as the decrease in threonine, isoleucine, methionine, serine and glycine, revealed a potential influence of UV-B on the GABA-mediated signalling and amino acid metabolism. UV-B had an overall positive impact on grape berry composition. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electrically driven deep ultraviolet MgZnO lasers at room temperature

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

Suja, Mohammad; Bashar, Sunayna Binte; Debnath, Bishwajit

Semiconductor lasers in the deep ultraviolet (UV) range have numerous potential applications ranging from water purification and medical diagnosis to high-density data storage and flexible displays. Nevertheless, very little success was achieved in the realization of electrically driven deep UV semiconductor lasers to date. Here, we report the fabrication and characterization of deep UV MgZnO semiconductor lasers. These lasers are operated with continuous current mode at room temperature and the shortest wavelength reaches 284 nm. The wide bandgap MgZnO thin films with various Mg mole fractions were grown on c-sapphire substrate using radio-frequency plasma assisted molecular beam epitaxy. Metal-semiconductor-metal (MSM)more » random laser devices were fabricated using lithography and metallization processes. Besides the demonstration of scalable emission wavelength, very low threshold current densities of 29-33 A/cm 2 are achieved. Furthermore, numerical modeling reveals that impact ionization process is responsible for the generation of hole carriers in the MgZnO MSM devices. The interaction of electrons and holes leads to radiative excitonic recombination and subsequent coherent random lasing.« less

Electrically driven deep ultraviolet MgZnO lasers at room temperature

DOE PAGES

Suja, Mohammad; Bashar, Sunayna Binte; Debnath, Bishwajit; ...

2017-06-01

Semiconductor lasers in the deep ultraviolet (UV) range have numerous potential applications ranging from water purification and medical diagnosis to high-density data storage and flexible displays. Nevertheless, very little success was achieved in the realization of electrically driven deep UV semiconductor lasers to date. Here, we report the fabrication and characterization of deep UV MgZnO semiconductor lasers. These lasers are operated with continuous current mode at room temperature and the shortest wavelength reaches 284 nm. The wide bandgap MgZnO thin films with various Mg mole fractions were grown on c-sapphire substrate using radio-frequency plasma assisted molecular beam epitaxy. Metal-semiconductor-metal (MSM)more » random laser devices were fabricated using lithography and metallization processes. Besides the demonstration of scalable emission wavelength, very low threshold current densities of 29-33 A/cm 2 are achieved. Furthermore, numerical modeling reveals that impact ionization process is responsible for the generation of hole carriers in the MgZnO MSM devices. The interaction of electrons and holes leads to radiative excitonic recombination and subsequent coherent random lasing.« less

EFFECTS OF LABORATORY ULTRAVIOLET LIGHT AND NATURAL SUNLIGHT ON SURVIVAL AND DEVELOPMENT OF RANA PIPIENS

EPA Science Inventory

Changes in solar ultraviolet (UV) radiation have been proposed as a possible factor contributing to seeming increases in hindlimb malformations in anuran amphibians in North America. A primary purpose of this study was to reproduce results from an earlier experiment in which Ran...

Assessment of Health Consequences of Steel Industry Welders' Occupational Exposure to Ultraviolet Radiation.

PubMed

Zamanian, Zahra; Mortazavi, Saied Mohammad Javad; Asmand, Ebrahim; Nikeghbal, Kiana

2015-01-01

Welding is among the most important frequently used processes in the industry with a wide range of applications from the food industry to aerospace and from precision tools to shipbuilding. The aim of this study was to assess the level of steel industry welders' exposure to ultraviolet (UV) radiation and to investigate the health impacts of these exposures. In this case-control study, we measured the intensity of UV at the workers' wrist in Fars Steel Company through manufacture of different types of heavy metal structures, using UV-meter model 666230 made by Leybold Co., from Germany. The population under the study comprised 400 people including 200 welders as the exposed group and 200 nonwelders as the unexposed group. The results of the questionnaire were analyzed using SPSS software, version 19. The average, standard deviation, maximum and minimum of the UV at the welders' wrist were 0.362, 0.346, 1.27, and 0.01 μW/cm(2), respectively. There was a significantly (P < 0.01) higher incidence of cataracts, keratoconjunctivitis, dermatitis and erythema in welders than in their nonwelders. This study showed that the time period of UV exposure in welders is higher than the permissible contact threshold level. Therefore, considering the outbreak of the eye and skin disorders in the welders, decreasing exposure time, reducing UV radiation level, and using personal protective equipment seem indispensable. As exposure to UV radiation can be linked to different types of skin cancer, skin aging, and cataract, welders should be advised to decrease their occupational exposures.

Assessment of Health Consequences of Steel Industry Welders’ Occupational Exposure to Ultraviolet Radiation

PubMed Central

Zamanian, Zahra; Mortazavi, Saied Mohammad Javad; Asmand, Ebrahim; Nikeghbal, Kiana

2015-01-01

Background: Welding is among the most important frequently used processes in the industry with a wide range of applications from the food industry to aerospace and from precision tools to shipbuilding. The aim of this study was to assess the level of steel industry welders’ exposure to ultraviolet (UV) radiation and to investigate the health impacts of these exposures. Methods: In this case–control study, we measured the intensity of UV at the workers’ wrist in Fars Steel Company through manufacture of different types of heavy metal structures, using UV-meter model 666230 made by Leybold Co., from Germany. Results: The population under the study comprised 400 people including 200 welders as the exposed group and 200 nonwelders as the unexposed group. The results of the questionnaire were analyzed using SPSS software, version 19. The average, standard deviation, maximum and minimum of the UV at the welders’ wrist were 0.362, 0.346, 1.27, and 0.01 μW/cm2, respectively. There was a significantly (P < 0.01) higher incidence of cataracts, keratoconjunctivitis, dermatitis and erythema in welders than in their nonwelders. Conclusions: This study showed that the time period of UV exposure in welders is higher than the permissible contact threshold level. Therefore, considering the outbreak of the eye and skin disorders in the welders, decreasing exposure time, reducing UV radiation level, and using personal protective equipment seem indispensable. As exposure to UV radiation can be linked to different types of skin cancer, skin aging, and cataract, welders should be advised to decrease their occupational exposures. PMID:26900437

CHARACTERIZATION OF RELATIVE SENSITIVITY OF AMPHIBIANS TO ULTRA VIOLET RADIATION

EPA Science Inventory

Different studies have demonstrated that solar ultraviolet (UV) radiation can adversely affect survival and development of embryonic and larval amphibians. However, because of among-laboratory variations in exposure profiles (artificial vs. natural sunlight; natural sunlight at d...

The Diffuse Radiation Field at High Galactic Latitudes

NASA Astrophysics Data System (ADS)

Akshaya, M. S.; Murthy, Jayant; Ravichandran, S.; Henry, R. C.; Overduin, James

2018-05-01

We have used GALEX observations of the north and south Galactic poles to study the diffuse ultraviolet background at locations where the Galactic light is expected to be at a minimum. We find offsets of 230–290 photon units in the far-UV (1531 Å) and 480–580 photon units in the near-UV (2361 Å). Of this, approximately 120 photon units can be ascribed to dust-scattered light and another 110 photon units (190 in the near-UV) to extragalactic radiation. The remaining radiation is, as yet, unidentified and amounts to 120–180 photon units in the far-UV and 300–400 photon units in the near-UV. We find that molecular hydrogen fluorescence contributes to the far-UV when the 100 μm surface brightness is greater than 1.08 MJy sr‑1.

Intercomparison of global, ultraviolet B and A radiation measurements in the Dead Sea region (Ein Bokek) and Beer Sheva.

PubMed

Kushelevsky, A P; Kudish, A I

1996-07-01

Thousands of patients suffering from psoriasis have been treated successfully in the Dead Sea area by climatological methods, without medication. This high rate of success, measured in terms of partial to complete plaque clearance and reported to exceed 85% after 3-4 weeks of treatment, has been assumed to be associated with a unique ultraviolet (UV) radiation environment present in the Dead Sea region. In order to broaden our knowledge of the UV radiation environment at the Dead Sea, continuous monitoring of UV (both B and A) and global radiation has recently been initiated at two sites--Ein Bokek (located in the vicinity of the Dead Sea 375 m below mean sea level) and Beer Sheva (315 m above mean sea level)--to facilitate an intercomparison of their respective radiation intensities. The results of the first year of a detailed study of the global, UVB and UVA radiation intensities measured at both sites are summarized and reported in terms of the monthly average daily, average midday (11:00-13:00) and the corresponding maximum values. The radiation data for clear days (based upon the absolute magnitude of the global radiation) were also analyzed to perform an intercomparison between Ein Bokek and Beer Sheva for a winter month and a summer month for which all three types of radiation data were available at both sites.

Short-term Dynamics of Photopriming Increase Carbon Loss During Litter Decomposition

NASA Astrophysics Data System (ADS)

Lin, Y.; King, J. Y.; Karlen, S. D.; Ralph, J.

2017-12-01

Solar radiation plays a key role in carbon (C) cycling by increasing the decomposition rates of plant litter through photodegradation. This process is particularly important in drylands where solar radiation is high and microbial activity may be limited by water availability. One mechanism of photodegradation may be the facilitation of microbial decomposition of litter by altering litter chemistry and consequently degradability, termed photopriming. However, it remains unclear to what extent photopriming contributes to litter decomposition. We evaluated photopriming by ultraviolet (UV) radiation through two laboratory experiments. In one experiment, we found that four months of UV exposure increased mass loss by 3-4% compared to dark treatment in two of three litter species commonly found in California oak savanna; however, UV exposure did not alter litter degradability as measured by microbial respiration in an incubation study. UV exposure had limited effects on lignin and other cell wall structures, but one month of microbial decomposition in the dark significantly reduced lignin β-aryl ether inter-unit linkages and acetylated xylans, which interestingly was the same pattern seen in litter exposed to UV radiation under field conditions and may account for the significant effects of UV exposure on litter mass loss observed in situ. These results indicate that microbial decomposition, not abiotic photodegradation, was ultimately responsible for changes in litter chemistry observed in the field. In a separate experiment, litter of a common grass was incubated for 128 days under either alternating UV radiation and dark conditions at two-day intervals or continuous darkness. During the second half of the experiment, alternating UV exposure increased CO2 production by 35% compared to continuous darkness, suggesting that UV exposure induces subtle but important changes in litter chemistry that facilitate microbial decomposition on a temporal scale of days. Together the results point to microbial facilitation as the primary mechanism of photodegradation and suggest that photopriming is governed by short-term dynamics at the litter-microbe interface. The C cycling associated with these short-term dynamics may be especially sensitive to anticipated increases in drought conditions in drylands.

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.

Antarctic Ultraviolet Radiation Climatology from Total Ozone Mapping Spectrometer Data

NASA Technical Reports Server (NTRS)

Lubin, Dan

2004-01-01

This project has successfully produced a climatology of local noon spectral surface irradiance covering the Antarctic continent and the Southern Ocean, the spectral interval 290-700 nm (UV-A, UV-B, and photosynthetically active radiation, PAR), and the entire sunlit part of the year for November 1979-December 1999. Total Ozone Mapping Spectrometer (TOMS) data were used to specify column ozone abundance and UV-A (360- or 380-nm) reflectivity, and passive microwave (MW) sea ice concentrations were used to specify the surface albedo over the Southern Ocean. For this latter task, sea ice concentration retrievals from the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) and its successor, the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I) were identified with ultraviolet/visible-wavelength albedos based on an empirical TOMS/MW parameterization developed for this purpose (Lubin and Morrow, 2001). The satellite retrievals of surface albedo and UV-A reflectivity were used in a delta-Eddington radiative transfer model to estimate cloud effective optical depth. These optical depth estimates were then used along with the total ozone and surface albedo to calculate the downwelling spectral UV and PAR irradiance at the surface. These spectral irradiance maps were produced for every usable day of TOMS data between 1979-1999 (every other day early in the TOMS program, daily later on).

The influence of ambient ultraviolet light on sperm quality and sexual ornamentation in three-spined sticklebacks (Gasterosteus aculeatus).

PubMed

Rick, Ingolf P; Mehlis, Marion; Eßer, Elisabeth; Bakker, Theo C M

2014-02-01

Exposure to enhanced levels of ambient ultraviolet (UV) radiation (UVR) can have adverse effects on aquatic organisms including damage at the cellular and molecular level and impairment of development, fecundity and survival. Much research has been conducted on the role of the harmful UVB radiation. However, due to its greater penetration in water the more abundant UVA radiation can also act as an environmental stressor. Little is known about UVR effects on sperm characteristics although sperm cells should be especially prone to UV-induced oxidative stress. Moreover, UV-related changes in oxidative status may affect the phenotypic expression of energetically costly sexual ornaments. We investigated the effects of long-term exposure to ecologically relevant levels of simulated UVA radiation on sperm quality and sexual ornamentation in three-spined sticklebacks (Gasterosteus aculeatus). Males were assigned to three spectral exposure treatments differing in the UV spectral part so that they received either enhanced, moderate or no UVA radiation. The results reveal that exposure to enhanced ambient UVA levels had detrimental effects on both male breeding coloration and sperm velocity providing evidence that UVR affects traits targeted by pre- and post-copulatory sexual selection. By highlighting the role of UVA as a factor influencing fitness-relevant traits, our findings may contribute to a better understanding of the consequences of current and future levels of solar UVR for mating systems and life history.

Ground-Based Measurement of Solar Ultraviolet Radiation

EPA Science Inventory

The National Exposure Research Laboratory (NERL) of the U.S. Environmental Protection Agency implemented a research program between 1996 and 2004 to measure UV at 21 unique locations through out the U.S. The program conducted long-term monitoring of UV to detect trends due to ch...

First UK trial of Xenex PX-UV, an automated ultraviolet room decontamination device in a clinical haematology and bone marrow transplantation unit.

PubMed

Beal, A; Mahida, N; Staniforth, K; Vaughan, N; Clarke, M; Boswell, T

2016-06-01

There is growing interest in the use of no-touch automated room decontamination devices within healthcare settings. Xenex PX-UV is an automated room disinfection device using pulsed ultraviolet (UV) C radiation with a short cycle time. To investigate the microbiological efficacy of this device when deployed for terminal decontamination of isolation rooms within a clinical haematology unit. The device was deployed in isolation rooms in a clinical haematology unit. Contact plates were applied to common touch points to determine aerobic total colony counts (TCCs) and samples collected using Polywipe™ sponges for detection of vancomycin-resistant enterococci (VRE). The device was easy to transport, easy to use, and it disinfected rooms rapidly. There was a 76% reduction in the TCCs following manual cleaning, with an additional 14% reduction following UV disinfection, resulting in an overall reduction of 90% in TCCs. There was a 38% reduction in the number of sites where VRE was detected, from 26 of 80 sites following manual cleaning to 16 of 80 sites with additional UV disinfection. The Xenex PX-UV device can offer a simple and rapid additional decontamination step for terminal disinfection of patient rooms. However, the microbiological efficacy against VRE was somewhat limited. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

1991-01-01

Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

Evaluation of thermal control coatings for use on solar dynamic radiators in low Earth orbit

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

1991-01-01

Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

The shady side of solar protection.

PubMed

Parsons, P G; Neale, R; Wolski, P; Green, A

1998-04-06

To determine the value of shade in protecting humans from solar ultraviolet (UV) radiation. Measurement with photometers of protection factors for ultraviolet B radiation (UVB) and for total solar radiation for different types of trees and other structures during the summer months (1995-1997) in south-east Queensland. (The protection ratio is the ratio of the intensity of UVB or total solar radiation in direct sunlight to that in shade.) For summer sun at midday, the mean (SD) UV protection ratio for the shade of trees (n = 65) was 4.21 (1.36) on a horizontal surface and 1.33 (0.30) on a vertical surface. In contrast, the mean (SD) protection ratio for total solar energy (primarily infrared) was much higher (12.1 [1.4]). Trees common in recreational areas in Australia (eucalypts: UV protection ratio, 3.52 [0.79]; Norfolk Island pines: UV protection ratio, 3.72 [0.98]) offered reduced protection compared with trees with more dense foliage (UV protection ratio, 5.48 [1.44]). Over a whole day, measurement of shade by trees and other structures showed that the UV protection ratio was lower in the morning and afternoon. Shade from awnings, buildings and hats gave similar results to those for trees. Both at midday and over a whole day satisfactory protection (UV protection ratio > 15) was obtained only in shade which eliminated exposure to the sky as well as to direct sunlight; for example, in thickly wooded areas and under low, widely overhanging structures. Most forms of shade, while useful, offer people insufficient protection from solar UV. A fair-skinned person sheltering under a tree could suffer sunburn after less than one hour. There is a need for appropriate design of structural shade, use of other solar protection measures in conjunction with shade, and research on behavioural responses to shade.

Inferring ultraviolet anatomical exposure patterns while distinguishing the relative contribution of radiation components

NASA Astrophysics Data System (ADS)

Vuilleumier, Laurent; Milon, Antoine; Bulliard, Jean-Luc; Moccozet, Laurent; Vernez, David

2013-05-01

Exposure to solar ultraviolet (UV) radiation is the main causative factor for skin cancer. UV exposure depends on environmental and individual factors, but individual exposure data remain scarce. While ground UV irradiance is monitored via different techniques, it is difficult to translate such observations into human UV exposure or dose because of confounding factors. A multi-disciplinary collaboration developed a model predicting the dose and distribution of UV exposure on the basis of ground irradiation and morphological data. Standard 3D computer graphics techniques were adapted to develop a simulation tool that estimates solar exposure of a virtual manikin depicted as a triangle mesh surface. The amount of solar energy received by various body locations is computed for direct, diffuse and reflected radiation separately. Dosimetric measurements obtained in field conditions were used to assess the model performance. The model predicted exposure to solar UV adequately with a symmetric mean absolute percentage error of 13% and half of the predictions within 17% range of the measurements. Using this tool, solar UV exposure patterns were investigated with respect to the relative contribution of the direct, diffuse and reflected radiation. Exposure doses for various body parts and exposure scenarios of a standing individual were assessed using erythemally-weighted UV ground irradiance data measured in 2009 at Payerne, Switzerland as input. For most anatomical sites, mean daily doses were high (typically 6.2-14.6 Standard Erythemal Dose, SED) and exceeded recommended exposure values. Direct exposure was important during specific periods (e.g. midday during summer), but contributed moderately to the annual dose, ranging from 15 to 24% for vertical and horizontal body parts, respectively. Diffuse irradiation explained about 80% of the cumulative annual exposure dose.

Photoprotection beyond ultraviolet radiation--effective sun protection has to include protection against infrared A radiation-induced skin damage.

PubMed

Schroeder, P; Calles, C; Benesova, T; Macaluso, F; Krutmann, J

2010-01-01

Solar radiation is well known to damage human skin, for example by causing premature skin ageing (i.e. photoageing). We have recently learned that this damage does not result from ultraviolet (UV) radiation alone, but also from longer wavelengths, in particular near-infrared radiation (IRA radiation, 760-1,440 nm). IRA radiation accounts for more than one third of the solar energy that reaches human skin. While infrared radiation of longer wavelengths (IRB and IRC) does not penetrate deeply into the skin, more than 65% of the shorter wavelength (IRA) reaches the dermis. IRA radiation has been demonstrated to alter the collagen equilibrium of the dermal extracellular matrix in at least two ways: (a) by leading to an increased expression of the collagen-degrading enzyme matrix metalloproteinase 1, and (b) by decreasing the de novo synthesis of the collagen itself. IRA radiation exposure therefore induces similar biological effects to UV radiation, but the underlying mechanisms are substantially different, specifically, the cellular response to IRA irradiation involves the mitochondrial electron transport chain. Effective sun protection requires specific strategies to prevent IRA radiation-induced skin damage. 2010 S. Karger AG, Basel.

Regulatory effect of Bcl-2 in ultraviolet radiation-induced apoptosis of the mouse crystalline lens

PubMed Central

DONG, YUCHEN; ZHENG, YAJUAN; XIAO, JUN; ZHU, CHAO; ZHAO, MEISHENG

2016-01-01

The aim of the present study was to analyze the role of Bcl-2 during the process of apoptosis in the mouse crystalline lens. In total, 12 normal mice served as the control group and 12 Bcl-2 knockout (K.O) mice served as the experimental group. The mouse crystalline lens was sampled for the detection of Bcl-2 and caspase-3 expression following exposure to ultraviolet (UV) radiation. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine Bcl-2 expression in the groups of normal mice receiving UV radiation or not receiving UV radiation. Samples of the murine crystalline lens were microscopically harvested and analyzed using western blotting. Apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Furthermore, caspase 3 activity was examined using enzyme-linked immunosorbent assay kits, and RT-qPCR was used to analyze caspase-3 expression levels. The results of the present study demonstrated that there was no statistically significant difference in the level of Bcl-2 gene transcription between the two groups. In addition, UV radiation did not change the macrostructure of the crystalline lens in the group of normal mice or the group of Bcl-2 K.O mice. The results of the TUNEL assay indicated that the normal-UV group exhibited a more significant apoptosis level compared with the Bcl-2 K.O-UV group. Furthermore, the mRNA expression level of caspase-3 in the normal-UV group was significantly higher compared with the normal-nonUV group (P<0.05), while the levels in the Bcl-2 K.O-UV group were significantly higher compared with the Bcl-2 K.O and normal-nonUV groups (P<0.05). In addition, the mRNA expression level of caspase-3 was significantly higher in the normal-UV, as compared with the Bcl-2 K.O-UV group (P<0.05), and the variation trends in caspase-3 activity were consistent. In conclusion, the results of the present study demonstrated that Bcl-2 may have an important role in the promotion of UV-induced apoptosis in the crystalline lens. PMID:26998022

Regulatory effect of Bcl-2 in ultraviolet radiation-induced apoptosis of the mouse crystalline lens.

PubMed

Dong, Yuchen; Zheng, Yajuan; Xiao, Jun; Zhu, Chao; Zhao, Meisheng

2016-03-01

The aim of the present study was to analyze the role of Bcl-2 during the process of apoptosis in the mouse crystalline lens. In total, 12 normal mice served as the control group and 12 Bcl-2 knockout (K.O) mice served as the experimental group. The mouse crystalline lens was sampled for the detection of Bcl-2 and caspase-3 expression following exposure to ultraviolet (UV) radiation. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine Bcl-2 expression in the groups of normal mice receiving UV radiation or not receiving UV radiation. Samples of the murine crystalline lens were microscopically harvested and analyzed using western blotting. Apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Furthermore, caspase 3 activity was examined using enzyme-linked immunosorbent assay kits, and RT-qPCR was used to analyze caspase-3 expression levels. The results of the present study demonstrated that there was no statistically significant difference in the level of Bcl-2 gene transcription between the two groups. In addition, UV radiation did not change the macrostructure of the crystalline lens in the group of normal mice or the group of Bcl-2 K.O mice. The results of the TUNEL assay indicated that the normal-UV group exhibited a more significant apoptosis level compared with the Bcl-2 K.O-UV group. Furthermore, the mRNA expression level of caspase-3 in the normal-UV group was significantly higher compared with the normal-nonUV group (P<0.05), while the levels in the Bcl-2 K.O-UV group were significantly higher compared with the Bcl-2 K.O and normal-nonUV groups (P<0.05). In addition, the mRNA expression level of caspase-3 was significantly higher in the normal-UV, as compared with the Bcl-2 K.O-UV group (P<0.05), and the variation trends in caspase-3 activity were consistent. In conclusion, the results of the present study demonstrated that Bcl-2 may have an important role in the promotion of UV-induced apoptosis in the crystalline lens.

Solar ultraviolet radiation induces biological alterations in human skin in vitro: relevance of a well-balanced UVA/UVB protection.

PubMed

Bernerd, Francoise; Marionnet, Claire; Duval, Christine

2012-06-01

Cutaneous damages such as sunburn, pigmentation, and photoaging are known to be induced by acute as well as repetitive sun exposure. Not only for basic research, but also for the design of the most efficient photoprotection, it is crucial to understand and identify the early biological events occurring after ultraviolet (UV) exposure. Reconstructed human skin models provide excellent and reliable in vitro tools to study the UV-induced alterations of the different skin cell types, keratinocytes, fibroblasts, and melanocytes in a dose- and time-dependent manner. Using different in vitro human skin models, the effects of UV light (UVB and UVA) were investigated. UVB-induced damages are essentially epidermal, with the typical sunburn cells and DNA lesions, whereas UVA radiation-induced damages are mostly located within the dermal compartment. Pigmentation can also be obtained after solar simulated radiation exposure of pigmented reconstructed skin model. Those models are also highly adequate to assess the potential of sunscreens to protect the skin from UV-associated damage, sunburn reaction, photoaging, and pigmentation. The results showed that an effective photoprotection is provided by broad-spectrum sunscreens with a potent absorption in both UVB and UVA ranges.

Photo-enhanced toxicity of fluoranthene to Gulf of Mexico marine organisms at different larval ages and ultraviolet light intensities.

PubMed

Finch, Bryson E; Stubblefield, William A

2016-05-01

Significant increases in toxicity have been observed as a result of polycyclic aromatic hydrocarbon (PAH) absorption of ultraviolet (UV) radiation in aquatic organisms. Early life stage aquatic organisms are predicted to be more susceptible to PAH photo-enhanced toxicity as a result of their translucence and tendency to inhabit shallow littoral or surface waters. The objective of the present study was to evaluate the sensitivity of varying ages of larval mysid shrimp (Americamysis bahia), inland silverside (Menidia beryllina), sheepshead minnow (Cyprinodon variegatus), and Gulf killifish (Fundulus grandis) to photo-enhanced toxicity and to examine the correlation between photo-enhanced toxicity and organism pigmentation. Organisms were exposed to fluoranthene and artificial UV light at different larval ages and results were compared using median lethal concentrations (LC50s) and the lethal time-to-death (LT50s). In addition, a high UV light intensity, short-duration (4-h) experiment was conducted at approximately 24 W/m(2) of ultraviolet radiation A (UV-A) and compared with a low-intensity, long-duration (12-h) experiment at approximately 8 W/m(2) of UV-A. The results indicated decreased toxicity with increasing age for all larval organisms. The amount of organism pigmentation was correlated with observed LC50 and LT50 values. High-intensity short-duration exposure resulted in greater toxicity than low-intensity long-duration UV treatments for mysid shrimp, inland silverside, and sheepshead minnow. Data from these experiments suggest that toxicity is dependent on age, pigmentation, UV light intensity, and fluoranthene concentration. © 2015 SETAC.

Synthesis of Deoxyribonucleic Acid After Ultraviolet Irradiation of Sensitive and Resistant Haemophilus influenzae

PubMed Central

Modak, Sohan P.; Setlow, Jane K.

1969-01-01

Synthesis of deoxyribonucleic acid (DNA) has been measured as a function of ultraviolet (UV) radiation dose in wild-type and seven UV-sensitive strains of Haemophilus influenzae. At the UV doses used, all strains were able to resume DNA synthesis, even those which are unable to excise pyrimidine dimers from their DNA. These excisionless strains showed longer UV-induced delays in DNA synthesis than all but one of the other strains. The longest delay was shown by DB117, a strain which can excise dimers but which is recombination deficient and unable to rejoin X ray-induced single-strand breaks. All strains showed a progressive decrease in sensitivity as they approached the stationary phase. PMID:5305934

Ultraviolet Light Curves of Gaia16apd in Superluminous Supernova Models

NASA Astrophysics Data System (ADS)

Tolstov, Alexey; Zhiglo, Andrey; Nomoto, Ken'ichi; Sorokina, Elena; Kozyreva, Alexandra; Blinnikov, Sergei

2017-08-01

Observations of Gaia16apd revealed extremely luminous ultraviolet emission among superluminous supernovae (SLSNe). Using radiation hydrodynamics simulations, we perform a comparison of UV light curves, color temperatures, and photospheric velocities between the most popular SLSN models: pair-instability supernova, magnetar, and interaction with circumstellar medium. We find that the interaction model is the most promising to explain the extreme UV luminosity of Gaia16apd. The differences in late-time UV emission and in color evolution found between the models can be used to link an observed SLSN event to the most appropriate model. Observations at UV wavelengths can be used to clarify the nature of SLSNe and more attention should be paid to them in future follow-up observations.

Effect of ultraviolet light on water- and fat-soluble vitamins in cow and goat milk.

PubMed

Guneser, O; Karagul Yuceer, Y

2012-11-01

The objective of this study was to investigate and compare the effects of UV light and heat treatment on vitamins A, B(2), C, and E in cow and goat milk. Vitamins were analyzed by reverse-phase high-pressure liquid chromatography. Ultraviolet and pasteurization treatments caused loss in vitamin C in milk. Pasteurization did not have any significant effect on vitamin B(2). However, UV light treatment decreased the amount of vitamin B(2) after several passes of milk through the UV system. In addition, UV light treatment decreased the amount of vitamins A and E. Vitamins C and E are more sensitive to UV light. UV light sensitivities of vitamins were C>E>A>B(2). These results show that UV light treatment decreases the vitamin content in milk. Also, the number of passes through the UV system and the initial amount of vitamins in milk are important factors affecting vitamin levels. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Luminescence of Tb-doped Ca 3Y 2(Si 3O 9) 2 oxide upon UV and VUV synchrotron radiation excitation

NASA Astrophysics Data System (ADS)

Dobrowolska, Anna; Zych, Eugeniusz

2011-07-01

Powders of calcium yttrium silicate, Ca 3Y 2(Si 3O 9) 2, containing 0.1-3% Tb 3+ were prepared using a sol-gel method and characterized with XRD, IR, UV-vis and UV-VUV spectroscopies at room temperature and 10 K. Structural analysis revealed pure monoclinic phase of Ca 3Y 2(Si 3O 9) 2 after heat-treatment at 1000 °C. Infrared spectroscopy showed that between 800 and 900 °C a short-range structural organization of the components proceeded, yet without crystallization. A strong emission of Tb 3+ had been observed both in the green part of the spectrum due to the 5D4→ 7FJ transitions and in the blue-violet region owing to the 5D3→ 7FJ radiative relaxation. The color of the light could be tuned from yellowish-green to bluish-white both by means of the dopant content and the temperature of synthesis. Efficient luminescence of Tb 3+-doped Ca 3Y 2(Si 3O 9) 2 phosphors could also be obtained upon stimulation with vacuum ultraviolet synchrotron radiation demonstrating that an energy transfer from the host to the Tb 3+ ions takes place.

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

PubMed

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

2015-12-30

Paraphenylenediamine (PPD), a derivative of paranitroaniline has been most commonly used as an ingredient of oxidative hair dye and permanent tattoos. We have studied the phototoxic potential of PPD under ambient ultraviolet radiation. PPD is photodegraded and form a novel photoproduct under UV A exposure. PPD shows a concentration dependent decrease in cell viability of human Keratinocyte cells (HaCaT) through MTT and NRU test. Significant intracellular ROS generation was measured by DCFDA assay. It caused an oxidative DNA damage via single stranded DNA breaks, micronuclei and CPD formation. Both lysosome and mitochondria is main target for PPD induced apoptosis which was proved through lysosomal destabilization and release of cathepsin B by immunofluorescence, real time PCR and western blot analysis. Cathepsin B process BID to active tBID which induces the release of cytochrome C from mitochondria. Mitochondrial depolarization was reported through transmission electron microscopy. The cathepsin inhibitor reduced the release of cytochrome C in PPD treated cells. Thus study suggests that PPD leads to apoptosis via the involvement of lysosome and mitochondria both under ambient UV radiation. Therefore, photosensitizing nature of hair dye ingredients should be tested before coming to market as a cosmetic product for the safety of human beings. Copyright © 2015 Elsevier B.V. All rights reserved.

Androgenic alopecia may have evolved to protect men from prostate cancer by increasing skin exposure to ultraviolet radiation.

PubMed

Kabai, Peter

2008-01-01

Androgenic alopecia affects populations adapted to colder climate, and individuals at an age and hormonal status susceptible to prostate cancer. Male pattern baldness enhances absorption of UV radiation on the top of the head, an area directly exposed to sunlight during everyday activities. Ultraviolet radiation is reported to reduce the risk of advanced prostate cancer. Here I propose that progression of androgenic alopecia rather than being a risk factor is a finely tuned mechanism evolved to protect against prostate cancer.

Solar ultraviolet-B radiation and vitamin D: a cross-sectional population-based study using data from the 2007 to 2009 Canadian Health Measures Survey

PubMed Central

2012-01-01

Background Exposure to solar ultraviolet-B (UV-B) radiation is a major source of vitamin D3. Chemistry climate models project decreases in ground-level solar erythemal UV over the current century. It is unclear what impact this will have on vitamin D status at the population level. The purpose of this study was to measure the association between ground-level solar UV-B and serum concentrations of 25-hydroxyvitamin D (25(OH)D) using a secondary analysis of the 2007 to 2009 Canadian Health Measures Survey (CHMS). Methods Blood samples collected from individuals aged 12 to 79 years sampled across Canada were analyzed for 25(OH)D (n = 4,398). Solar UV-B irradiance was calculated for the 15 CHMS collection sites using the Tropospheric Ultraviolet and Visible Radiation Model. Multivariable linear regression was used to evaluate the association between 25(OH)D and solar UV-B adjusted for other predictors and to explore effect modification. Results Cumulative solar UV-B irradiance averaged over 91 days (91-day UV-B) prior to blood draw correlated significantly with 25(OH)D. Independent of other predictors, a 1 kJ/m2 increase in 91-day UV-B was associated with a significant 0.5 nmol/L (95% CI 0.3-0.8) increase in mean 25(OH)D (P = 0.0001). The relationship was stronger among younger individuals and those spending more time outdoors. Based on current projections of decreases in ground-level solar UV-B, we predict less than a 1 nmol/L decrease in mean 25(OH)D for the population. Conclusions In Canada, cumulative exposure to ambient solar UV-B has a small but significant association with 25(OH)D concentrations. Public health messages to improve vitamin D status should target safe sun exposure with sunscreen use, and also enhanced dietary and supplemental intake and maintenance of a healthy body weight. PMID:22894564

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.

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.

Biophysical mechanisms of modification of skin optical properties in the UV wavelength range with nanoparticles

NASA Astrophysics Data System (ADS)

Popov, A. P.; Priezzhev, A. V.; Lademann, J.; Myllylä, R.

2009-05-01

In this paper, by means of the Mie theory and Monte Carlo simulations we investigate modification of optical properties of the superficial layer of human skin (stratum corneum) for 310- and 400-nm ultraviolet (UV) radiation by embedding of 35-200-nm-sized particles of titanium dioxide (TiO2) and silicon (Si). Problem of skin protection against UV light is of major importance due to increased frequency of skin cancer provoked by excessive doses of accepted UV radiation. For 310-nm light, the optimal sizes of the TiO2 and Si particles are found to be 62 and 55 nm, respectively, and for 400-nm radiation, 122 and 70 nm, respectively.

The Role of Optical Radiations in Skin Cancer

PubMed Central

Palla, Marco; Di Trolio, Rossella; Mozzillo, Nicola; Ascierto, Paolo A.

2013-01-01

Purpose. Electromagnetic radiation with wavelength in the range 100 nm to 1 mm is known as optical radiation and includes ultraviolet radiation, the visible spectrum, and infrared radiation. The deleterious short- and long-term biological effects of ultraviolet radiation, including melanoma and other skin cancers, are well recognized. Infrared radiation may also have damaging biological effects. Methods. The objective of this review was to assess the literature over the last 15 years and to summarize correlations between exposure to optical radiation and the risk of melanoma and other cancers. Results. There is a clear correlation between exposure to UV radiation and the development of skin cancer. Most importantly, a strong association between artificial UV radiation exposure, for example, tanning devices, and the risk of melanoma and squamous cell carcinoma has been clearly demonstrated. There is no clear evidence that exposure to IR and laser radiation may increase the risk of skin cancer, although negative health effects have been observed. Conclusions. Preventative strategies that involve provision of public information highlighting the risks associated with exposure to sunlight remain important. In addition, precautionary measures that discourage exposure to tanning appliances are required, as is legislation to prevent their use during childhood. PMID:23710365

Photosynthetic benefits of ultraviolet-A to Pimelea ligustrina, a woody shrub of sub-alpine Australia.

PubMed

Turnbull, Tarryn L; Barlow, Alexandra M; Adams, Mark A

2013-10-01

The definition of photosynthetically active radiation (Q) as the visible waveband (λ 400-700 nm) is a core assumption of much of modern plant biology and global models of carbon and water fluxes. On the other hand, much research has focused on potential mutation and damage to leaves caused by ultraviolet (UV) radiation (280-400 nm), and anatomical and physiological adaptations that help avoid such damage. Even so, plant responses to UV-A are poorly described and, until now, photosynthetic utilization of UV-A has not been elucidated under full light conditions in the field. We found that the UV-A content of sunlight increased photosynthetic rates in situ by 12% in Pimelea ligustrina Labill., a common and indigenous woody shrub of alpine ecosystems of the Southern Hemisphere. Compared to companion shrubs, UV-A-induced photosynthesis in P. ligustrina resulted from reduced physical and chemical capacities to screen UV-A at the leaf surface (illustrated by a lack of cuticle and reduced phenol index) and the resulting ability of UV-A to excite chlorophyll (Chl) a directly, and via energy provided by the carotenoid lutein. A screening of 55 additional sub-alpine species showed that 47% of the plant taxa also display Chl a fluorescence under UV-A. If Chl a fluorescence indicates potential for photosynthetic gain, continued exclusion of UV-A from definitions of Q in this ecosystem could result in underestimates of measured and modeled rates of photosynthesis and miscalculation of potential for carbon sequestration. We suggest that carbon gain for alpine environs across the globe could be similarly underestimated given that UV-A radiation increases with altitude and that the frequently dominant herb and grass life-forms often transmit UV-A through the epidermis.

Ultraviolet and visible radiation at Barrow, Alaska: Climatology and influencing factors on the basis of version 2 National Science Foundation network data

NASA Astrophysics Data System (ADS)

Bernhard, Germar; Booth, Charles R.; Ehramjian, James C.; Stone, Robert; Dutton, Ellsworth G.

2007-05-01

Spectral ultraviolet (UV) and visible irradiance has been measured near Barrow, Alaska (71°N, 157°W), between 1991 and 2005 with a SUV-100 spectroradiometer. The instrument is part of the U.S. National Science Foundation's UV Monitoring Network. Here we present results based on the recently produced "version 2" data release, which supersedes published "version 0" data. Cosine error and wavelength-shift corrections applied to the new version increased biologically effective UV dose rates by 0-10%. Corrected clear-sky measurements of different years are typically consistent to within ±3%. Measurements were complemented with radiative transfer model calculations to retrieve total ozone and surface albedo from measured spectra and for the separation of the different factors influencing UV and visible radiation. A climatology of UV and visible radiation was established, focusing on annual cycles, trends, and the effect of clouds. During several episodes in spring of abnormally low total ozone, the daily UV dose at 305 nm exceeded the climatological mean by up to a factor of 2.6. Typical noontime UV Indices during summer vary between 2 and 4; the highest UV Index measured was 5.0 and occurred when surface albedo was unusually high. Radiation levels in the UV-A and visible exhibit a strong spring-autumn asymmetry. Irradiance at 345 nm peaks on approximately 20 May, 1 month before the solstice. This asymmetry is caused by increased cloudiness in autumn and high albedo in spring, when the snow covered surface enhances downwelling UV irradiance by up to 57%. Clouds reduce UV radiation at 345 nm on average by 4% in March and by more than 40% in August. Aerosols reduce UV by typically 5%, but larger reductions were observed during Arctic haze events. Stratospheric aerosols from the Pinatubo eruption in 1991 enhanced spectral irradiance at 305 nm for large solar zenith angles. The year-to-year variations of spectral irradiance at 305 nm and of the UV Index are mostly caused by variations in total ozone and cloudiness. Changes in surface albedo that may occur in the future can have a marked impact on UV levels between May and July. No statistically significant trends in monthly mean noontime irradiance were found.

An estimation methode for measurement of ultraviolet radiation during nondestructive testing

NASA Astrophysics Data System (ADS)

Hosseinipanah, M.; Movafeghi, A.; Farvadin, D.

2018-04-01

Dye penetrant testing and magnetic particle testing are among conventional NDT methods. For increased sensitivity, fluorescence dyes and particles can be used with ultraviolet (black) lights. UV flaw detection lights have different spectra. With the help of photo-filters, the output lights are transferred to UV-A and visible zones. UV-A light can be harmful to human eyes in some conditions. In this research, UV intensity and spectrum were obtained by a Radio-spectrometer for two different UV flaw detector lighting systems. According to the standards such as ASTM E709, UV intensity must be at least 10 W/m2 at a distance of 30 cm. Based on our measurements; these features not achieved in some lamps. On the other hand, intensity and effective intensity of UV lights must be below the some limits for prevention of unprotected eye damage. NDT centers are usually using some type of UV measuring devices. A method for the estimation of effective intensity of UV light has been proposed in this research.

REPRESSOR OF ULTRAVIOLET-B PHOTOMORPHOGENESIS function allows efficient phototropin mediated ultraviolet-B phototropism in etiolated seedlings.

PubMed

Vanhaelewyn, Lucas; Schumacher, Paolo; Poelman, Dirk; Fankhauser, Christian; Van Der Straeten, Dominique; Vandenbussche, Filip

2016-11-01

Ultraviolet B (UV-B) light is a part of the solar radiation which has significant effects on plant morphology, even at low doses. In Arabidopsis, many of these morphological changes have been attributed to a specific UV-B receptor, UV resistance locus 8 (UVR8). Recent findings showed that next to phototropin regulated phototropism, UVR8 mediated signaling is able of inducing directional bending towards UV-B light in etiolated seedlings of Arabidopsis, in a phototropin independent manner. In this study, kinetic analysis of phototropic bending was used to evaluate the relative contribution of each of these pathways in UV-B mediated phototropism. Diminishing UV-B light intensity favors the importance of phototropins. Molecular and genetic analyses suggest that UV-B is capable of inducing phototropin signaling relying on phototropin kinase activity and regulation of NPH3. Moreover, enhanced UVR8 responses in the UV-B hypersensitive rup1rup2 mutants interferes with the fast phototropin mediated phototropism. Together the data suggest that phototropins are the most important receptors for UV-B induced phototropism in etiolated seedlings, and a RUP mediated negative feedback pathway prevents UVR8 signaling to interfere with the phototropin dependent response. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Ultraviolet-C irradiation for inactivation of viruses in foetal bovine serum.

PubMed

Vaidya, Vivek; Dhere, Rajeev; Agnihotri, Snehal; Muley, Ravindra; Patil, Sanjay; Pawar, Amit

2018-07-05

Foetal Bovine Serum (FBS) and porcine trypsin are one of the essential raw materials used in the manufacturing of cell culture based viral vaccines. Being from animal origin, these raw materials can potentially contaminate the final product by known or unknown adventitious agents. The issue is more serious in case of live attenuated viral vaccines, where there is no inactivation step which can take care of such adventitious agents. It is essential to design production processes which can offer maximum viral clearance potential for animal origin products. Ultraviolet-C irradiation is known to inactivate various adventitious viral agents; however there are limited studies on ultraviolet inactivation of viruses in liquid media. We obtained a recently developed UVivatec ultraviolet-C (UV-C) irradiation based viral clearance system for evaluating its efficacy to inactivate selected model viruses. This system has a unique design with spiral path of liquid allowing maximum exposure to UV-C light of a short wavelength of 254 nm. Five live attenuated vaccine viruses and four other model viruses were spiked in tissue culture media and exposed to UV-C irradiation. The pre and post UV-C irradiation samples were analyzed for virus content to find out the extent of inactivation of various viruses. These experiments showed substantial log reduction for the majority of the viruses with few exceptions based on the characteristics of these viruses. Having known the effect of UV irradiation on protein structure, we also evaluated the post irradiation samples of culture media for growth promoting properties using one of the most fastidious human diploid cells (MRC-5). UV-C exposure did not show any notable impact on the nutritional properties of culture media. The use of an UV-C irradiation based system is considered to be promising approach to mitigate the risk of adventitious agents in cell culture media arising through animal derived products. Copyright © 2018 Elsevier Ltd. All rights reserved.

Skylab

NASA Image and Video Library

1973-01-01

This chart describes scientific parameters of the Skylab Ultraviolet (UV) Scanning Polychromator Spectroheliometer, one the eight Apollo Telescope Mount facilities. It was designed to observe and provide temporal changes in UV radiation emitted by the Sun's chromosphere and lower corona. The Marshall Space Flight Center had program management responsibility for the development of skylab hardware and experiments.

Skylab

NASA Image and Video Library

1970-01-01

This 1970 photograph shows the flight unit for Skylab's Ultraviolet (UV) Scarning Polychromator Spectroheliometer, an Apollo Telescope Mount (ATM) facility. It was designed to observe temporal changes in UV radiation emitted by the Sun's chromosphere and lower corona. The Marshall Space Flight Center had program management responsibility for the development of Skylab hardware and experiments.

CHARACTERIZE INTERACTIONS BETWEEN ECOSYSTEM FUNCTIONING AND CHANGES IN CLIMATE, UV, AND LAND USE

EPA Science Inventory

Assessments of the long-term impacts of global changes in climate, ultraviolet (UV) radiation and land use on ecosystems require scientific data, concepts and models that describe the responses of ecosystem health to stresses related to the changes as well as information and mode...

A FIELD DEMONSTRATION OF THE UV/OXIDATION TECHNOLOGY TO TREAT GROUND WATER WITH VOCS

EPA Science Inventory

This paper presents the field evaluation results of the ultraviolet radiation (UV)/oxidation technology developed by Ultrox International, Santa Ana, California. The field evaluation was performed at the Loretta Barrel and Drum (LB&D) site in San Jose, California, under the Super...

INTERACTIONS OF LIGHT AND CHEMICAL REACTIONS IN THE AQUATIC ENVIRONMENT: KINETIC AND MECHANISTIC ASPECTS

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...

OPTICAL CHARACTERISTICS OF NATURAL WATERS PROTECT AMPHIBIAN POPULATIONS FROM UV-B IN THE US PACIFIC NORTHWEST

EPA Science Inventory

Increased exposure to ultraviolet-B (UV-B) radiation has been proposed as a major environmental stressor leading to global amphibian declines. Prior experimental evidence from the US Pacific Northwest (PNW) indicating the acute embryonic sensitivity of at least 4 amphibian specie...

Sunscreen Agents in the Environment: Determination by HPLC-ESI-MS/MS and GC-MS and Calculation of Phototoxicity

EPA Science Inventory

Ultraviolet (UV) filters, also known as sunscreen agents, are chemicals widely used in cosmetics, sunscreens, and plastics to block UV radiation from the sun. There have been studies that show some sunscreen agents demonstrate estrogenicity and multiple hormonal activities in vi...

Assessment of the Phototoxicity of Weathered Alaska North Slope Crude Oil to Juvenile Pink Salmon

EPA Science Inventory

Petroleum products are known to have greater toxicity to the translucent embryos and larvae of aquatic organisms in the presence of ultraviolet radiation (UV) compared to toxicity determined in tests performed under standard laboratory lighting with minimal UV. This study assesse...

Use of UV-C treatments to maintain quality and extend the shelf life of green fresh-cut bell pepper (Capsicum annuum L.).

PubMed

Rodoni, Luis M; Concellón, Analía; Chaves, Alicia R; Vicente, Ariel R

2012-06-01

The objective of this work was to select a Ultraviolet-C (UV-C) treatment for fresh-cut mature green bell pepper, and to evaluate the effect of its combination with refrigeration on quality maintenance. Bell pepper sticks were treated with 0, 3, 10, or 20 kJ/m² UV-C in the outer (O), inner (I), or both sides of the pericarp (I/O) and stored for 8 d at 10 °C. During the first 5 d of storage, all UV-C treatments reduced deterioration as compared to the control. The treatment with 20 kJ/m² I/O was the most effective to reduce deterioration, and was used for further evaluations. In a second group of experiments, mature green bell pepper sticks were treated with 20 kJ/m² I/O, stored at 5 °C for 7 or 12 d and assessed for physical and chemical analysis, and microbiological quality. UV-C-treated fruit showed lower exudates and shriveling than the control. UV exposure also reduced decay, tissue damage, and electrolyte leakage. After 12 d at 5 °C, UV-C irradiated peppers remained firmer and had higher resistance to deformation than the control. The UV-C treatments also reduced weight loss and pectin solubilization. UV-C exposure decreased the counts of mesophile bacteria and molds, and did not affect acidity or sugars. UV-C-treated fruit stored for 0 or 7 d at 5 °C did not show major differences in antioxidants from the control as measured against DPPH(•) or ABTS(•)⁺ radicals. Results suggest that UV-C exposure is useful to maintain quality of refrigerated fresh-cut green pepper. Exposure to UV-C radiation before packing and refrigeration could be a useful nonchemical alternative to maintain quality and reduce postharvest losses in the fresh-cut industry. © 2012 Institute of Food Technologists®

A RADIOBIOLOGICAL ANALOGY BETWEEN MEASLES VIRUS AND TEMPERATE PHAGES

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

Ackerman, P.H.; Black, F.L.

1961-02-01

Measles virus was found to be more resistant to ultraviolet (uv) than to ionizing radiations. The capacity of monkey kidney cells to grow unirradiated measles virus or measles virus irradiated with gamma rays was not affected appreciably by uv irradiation of the cells. However, the capacity of cells to grow uv irradiated virus was reduced by uv irradiation of the cells. In contrast, uv irradiation of cells did not affect their capacity to grow uv- treated polio virus. These effects of radiation on the measles virus system are analogous to effects on the phage P22 system and are compatible withmore » the hypothesis of cellular repair of damaged virus previously suggested for the temperate phage. (auth)« less

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

NASA Technical Reports Server (NTRS)

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

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

PubMed

Mok, Jungbin; Krotkov, Nickolay A; Arola, Antti; Torres, Omar; Jethva, Hiren; Andrade, Marcos; Labow, Gordon; Eck, Thomas F; Li, Zhanqing; Dickerson, Russell R; Stenchikov, Georgiy L; Osipov, Sergey; Ren, Xinrong

2016-11-11

The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or "brown" carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths. Using the ground-based inversion of column effective imaginary refractive index in the range 305-368 nm, we quantified a strong spectral dependence of absorption by BrC in the UV and diminished ultraviolet B (UV-B) radiation reaching the surface. Reduced UV-B means less erythema, plant damage, and slower photolysis rates. We use a photochemical box model to show that relative to black carbon (BC) alone, the combined optical properties of BrC and BC slow the net rate of production of ozone by up to 18% and lead to reduced concentrations of radicals OH, HO 2 , and RO 2 by up to 17%, 15%, and 14%, respectively. The optical properties of BrC aerosol change in subtle ways the generally adverse effects of smoke from biomass burning.

Optical radiation in modern medicine

PubMed Central

Sowa, Paweł; Rutkowska-Talipska, Joanna; Rutkowski, Krzysztof; Kosztyła-Hojna, Bożena

2013-01-01

Optical radiation extends between microwaves and X-rays of the electromagnetic radiation and includes ultraviolet (UV), visible light (VL) and infrared (IR) components. The dose of radiation that reaches the skin is influenced by the ozone layer, position of the Sun, latitude, altitude, cloud cover and ground reflections. The photobiological effects of UV, VL and IR bands depend on their wavelength, frequency and mechanism of action. They are modified by the thickness, structure, vasculature and pigmentation of skin's stratum corneum, epidermis and dermis. Following absorption, IR affects the body mainly through transfer of thermal energy to tissues. Visible light and skin interact either thermally or photochemically, whereas UV acts mainly photochemically. Optical radiation in the form of sunlight therapy had been used already in ancient times. Nowadays IR, VL and UV are widely applied in the therapy of allergic, dermatological, cardiovascular, respiratory, rheumatic, neonatal, pediatric and psychiatric disorders. PMID:24278082

UV Induced Epigenetic Field Effect as a Target for Melanoma Therapy and Prevention

DTIC Science & Technology

2017-06-01

initiators or selected for during disease progression highlighting our lack in knowledge of the critical molecular targets in the initiation of UV...changes in the underlying molecular mechanisms of UV-induced melanoma. This would be the first evidence epigenetic alterations from UV-induced...i di id l i k d h l d fi li d i i15. SUBJECT TERMS Skin-cancer, melanoma, ultraviolet-radiation, epigenetics, methylation, genetics , melanomagenesis

Ultraviolet spectra of extreme nearby star-forming regions - approaching a local reference sample for JWST

NASA Astrophysics Data System (ADS)

Senchyna, Peter; Stark, Daniel P.; Vidal-García, Alba; Chevallard, Jacopo; Charlot, Stéphane; Mainali, Ramesh; Jones, Tucker; Wofford, Aida; Feltre, Anna; Gutkin, Julia

2017-12-01

Nearby dwarf galaxies provide a unique laboratory in which to test stellar population models below Z⊙/2. Such tests are particularly important for interpreting the surprising high-ionization ultraviolet (UV) line emission detected at z > 6 in recent years. We present HST/COS UV spectra of 10 nearby metal-poor star-forming galaxies selected to show He II emission in SDSS optical spectra. The targets span nearly a dex in gas-phase oxygen abundance (7.8 < 12 + log O/H < 8.5) and present uniformly large specific star formation rates (sSFR ∼102 Gyr-1). The UV spectra confirm that metal-poor stellar populations can power extreme nebular emission in high-ionization UV lines, reaching C III] equivalent widths comparable to those seen in systems at z ∼ 6-7. Our data reveal a marked transition in UV spectral properties with decreasing metallicity, with systems below 12 + log O/H ≲ 8.0 (Z/Z⊙ ≲ 1/5) presenting minimal stellar wind features and prominent nebular emission in He II and C IV. This is consistent with nearly an order of magnitude increase in ionizing photon production beyond the He+-ionizing edge relative to H-ionizing flux as metallicity decreases below a fifth solar, well in excess of standard stellar population synthesis predictions. Our results suggest that often-neglected sources of energetic radiation such as stripped binary products and very massive O-stars produce a sharper change in the ionizing spectrum with decreasing metallicity than expected. Consequently, nebular emission in C IV and He II powered by these stars may provide useful metallicity constraints in the reionization era.

The role of supplemental ultraviolet-B radiation in altering the metabolite profile, essential oil content and composition, and free radical scavenging activities of Coleus forskohlii, an indigenous medicinal plant.

PubMed

Takshak, Swabha; Agrawal, S B

2016-04-01

The effects of supplemental ultraviolet-B (s-UV-B; 3.6 kJ m(-2) day(-1) above ambient) radiation were investigated on plant metabolite profile, essential oil content and composition, and free radical scavenging capacities of methanolic extracts of Coleus forskohlii (an indigenous medicinal plant) grown under field conditions. Essential oil was isolated using hydrodistillation technique while alterations in metabolite profile and oil composition were determined via gas chromatography-mass spectroscopy (GC-MS). Leaf and root methanolic extracts were investigated via various in vitro assays for their DPPH radical-, superoxide radical-, hydrogen peroxide-, hydroxyl radical-, and nitric oxide radical scavenging activities, ferrous ion chelating activity, and reducing power. Phytochemical analysis revealed the presence of alkaloids, anthocyanins, coumarins, flavonoids, glycosides, phenols, saponins, steroids, tannins, and terpenoids. Oil content was found to be reduced (by ∼7 %) in supplemental UV-B (s-UV-B) treated plants; the composition of the plant extracts as well as essential oil was also considerably altered. Methanolic extracts from treated plant organs showed more potency as free radical scavengers (their EC50 values being lower than their respective controls). Anomalies were observed in Fe(2+) chelating activity for both leaves and roots. The present study concludes that s-UV-B adversely affects oil content in C. forskohlii and also alters the composition and contents of metabolites in both plant extracts and oil. The results also denote that s-UV-B treated plant organs might be more effective in safeguarding against oxidative stress, though further studies are required to authenticate these findings.

UPDATE ON COORDINATED STUDIES OF AMPHIBIAN DISTRIBUTIONS AND UV RADIATION

EPA Science Inventory

In February of 2000 researchers from the EPA, the National Park Service, other governmental agencies, and academia formulated a plan for coordinated studies of amphibian distributions and aquatic ultraviolet radiation exposure risks in several national parks. At this point we hav...

Ultraviolet radiation exposure triggers neurokinin-1 receptor upregulation in ocular tissues in vivo.

PubMed

Gross, Janine; Wegener, Alfred R; Kronschlaeger, Martin; Holz, Frank G; Schönfeld, Carl-Ludwig; Meyer, Linda M

2018-04-26

The purpose of this study was to investigate the neurokinin receptor-1 (NKR-1) protein expression in ocular tissues before and after supra-cataract threshold ultraviolet radiation (UVR-B peak at 312 nm) exposure in vivo in a mouse model. Six-week-old C57Bl/6 mice were unilaterally exposed to a single (2.9 kJ/m 2 ) and an above 3-fold UVR-B cataract threshold dose (9.4 kJ/m 2 ) of UVR. UVR-exposure (λpeak = 312 nm) was performed in mydriasis using a Bio-Spectra exposure system. After latency periods of 3 and 7 days, eyes were fixed in 4% paraformaldehyde, embedded in paraffin, sectioned and stained with fluorescence coupled antibody for NKR-1 and DAPI for cell nuclei staining. Control animals received only anesthesia but no UVR-exposure. Cataract development was documented with a Leica dark-field microscope and quantified as integrated optical density (IOD). NKR-1 is ubiquitously present in ocular tissues. An above 3-fold cataract threshold dose of UV-radiation induced NKR-1 upregulation after days 3 and 7 in the epithelium and endothelium of the cornea, the endothelial cells of the iris vessels, the pigmented epithelium/stroma of the ciliary body, the lens epithelium, pronounced in the nuclear bow region and the inner plexiform layer of the retina. A significant upregulation of NKR-1 could not be provoked with a single cataract threshold dose (2.9 kJ/m 2 UVR-B) ultraviolet irradiation. All exposed eyes developed anterior subcapsular cataracts. Neurokinin-1 receptor is present ubiquitously in ocular tissues including the lens epithelium and the nuclear bow region of the lens. UV-radiation exposure to an above 3-fold UVR-B cataract threshold dose triggers NKR-1 upregulation in the eye in vivo. The involvement of inflammation in ultraviolet radiation induced cataract and the role of neuroinflammatory peptides such as substance P and its receptor, NKR-1, might have been underestimated to date. Copyright © 2018. Published by Elsevier Ltd.

The ultraviolet environment of Mars: biological implications past, present, and future.

PubMed

Cockell, C S; Catling, D C; Davis, W L; Snook, K; Kepner, R L; Lee, P; McKay, C P

2000-08-01

A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment, past and present. Biological action spectra for DNA inactivation and chloroplast (photosystem) inhibition are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Over time Mars has probably experienced an increasingly inhospitable photobiological environment, with present instantaneous DNA weighted irradiances 3.5-fold higher than they may have been on early Mars. This is in contrast to the surface of Earth, which experienced an ozone amelioration of the photobiological environment during the Proterozoic and now has DNA weighted irradiances almost three orders of magnitude lower than early Earth. Although the present-day martian UV flux is similar to that of early Earth and thus may not be a critical 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. Microbial strategies for protection against UV radiation are considered in the light of martian photobiological calculations, past and present. Data are also presented for the effects of hypothetical planetary atmospheric manipulations on the martian UV radiation environment with estimates of the biological consequences of such manipulations.

The ultraviolet environment of Mars: biological implications past, present, and future

NASA Technical Reports Server (NTRS)

Cockell, C. S.; Catling, D. C.; Davis, W. L.; Snook, K.; Kepner, R. L.; Lee, P.; McKay, C. P.

2000-01-01

A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment, past and present. Biological action spectra for DNA inactivation and chloroplast (photosystem) inhibition are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Over time Mars has probably experienced an increasingly inhospitable photobiological environment, with present instantaneous DNA weighted irradiances 3.5-fold higher than they may have been on early Mars. This is in contrast to the surface of Earth, which experienced an ozone amelioration of the photobiological environment during the Proterozoic and now has DNA weighted irradiances almost three orders of magnitude lower than early Earth. Although the present-day martian UV flux is similar to that of early Earth and thus may not be a critical 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. Microbial strategies for protection against UV radiation are considered in the light of martian photobiological calculations, past and present. Data are also presented for the effects of hypothetical planetary atmospheric manipulations on the martian UV radiation environment with estimates of the biological consequences of such manipulations.

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.

An optimal thermal evaporation synthesis of c-axis oriented ZnO nanowires with excellent UV sensing and emission characteristics

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

Saha, Tridib, E-mail: tridib.saha@monash.edu; Achath Mohanan, Ajay, E-mail: ajay.mohanan@monash.edu; Swamy, Varghese, E-mail: varghese.swamy@monash.edu

Highlights: • c-Axis alignment of ZnO nanowires was optimized using self-seeding thermal evaporation method. • Influence of purified air on the morphology and optoelectronic properties were studied. • Nanowires grown under optimal conditions exhibit strong UV emission peak in PL spectrum. • Optimized growth condition establish nanowires of excellent UV sensing characteristics - Abstract: Well-aligned (c-axis oriented) ZnO nanowire arrays were successfully synthesized on Si (1 0 0) substrates through an optimized self-seeding thermal evaporation method. An open-ended chemical vapor deposition (CVD) setup was used in the experiment, with argon and purified air as reaction gases. Epitaxial growth of c-axismore » oriented ZnO nanowires was observed for 5 sccm flow rate of purified air, whereas Zn/Zn suboxide layers and multiple polycrystalline layers of ZnO were obtained for absence and excess of purified air, respectively. Ultraviolet (UV) sensing and emission properties of the as-grown ZnO nanostructures were investigated through the current–voltage (I–V) characteristics of the nanowires under UV (λ = 365 nm) illumination of 8 mW/cm{sup 2} and using photoluminescence spectra. Nanowires grown under optimum flow of air emitted four times higher intensity of 380 nm UV light as well as exhibited 34 times higher UV radiation sensitivity compared to that of other nanostructures synthesized in this study.« less

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.

A simple resonance enhanced laser ionization scheme for CO via the A1Π state

NASA Astrophysics Data System (ADS)

Sun, Z. F.; von Zastrow, A. D.; Parker, D. H.

2017-07-01

We investigate the laser ionization process taking place when the CO molecule is exposed to vacuum ultraviolet (VUV) radiation resonant with the CO A1Π (v = 0) ← X1Σ+ (v = 0) transition around 154 nm, along with the ultraviolet (UV) and visible (Red) radiation used to generate VUV by four-wave difference-frequency mixing. By measuring the CO+ ion recoil and a room temperature gas spectrum, it is possible to assign the ionization process as 1 + 1' + 1'' REMPI where the one-photon steps refer to the VUV, UV, and Red radiation, respectively. Resonance enhanced ionization of rotational states around J = 12 arise due to the overlap of the fixed wavelength UV (˜250 nm) with the R band-head of a transition assigned to CO E1Π (v = 6) ← A1Π (v = 0) with a term value of 104 787.5 cm-1. The REMPI process is efficient and polarization sensitive and should be useful in a wide range of studies involving nascent CO.

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.

UV index experimental values during the years 2000 and 2001 from the Spanish broadband UV-B radiometric network.

PubMed

Martínez-Lozano, José A; Marín, María J; Tena, Fernando; Utrillas, María P; Sánchez-Muniosguren, Luis; González-Frías, Carlos; Cuevas, Emilio; Redondas, Alberto; Lorente, Jerónimo; de Cabo, Xavier; Cachorro, Victoria; Vergaz, Ricardo; de Frutos, Angel; Díaz, Juan P; Expósito, Francisco J; de la Morena, Benito; Vilaplana, José M

2002-08-01

An analysis is made of experimental ultraviolet erythemal solar radiation data measured during the years 2000 and 2001 by the Spanish UV-B radiation evaluation and prediction network. This network consists of 16 Robertson-Berger type pyranometers for evaluating solar erythemal radiation and five Brewer spectroradiometers for evaluating the stratospheric ozone. On the basis of these data the Ultraviolet Index (UVI) was evaluated for the measuring stations that are located either in coastal regions or in the more densely populated regions inland on the Iberian Peninsula. It has been checked that in most cases the maximum irradiance values corresponded to solar noon, although there were exceptions that could be explained by cloudiness. The maximum experimental values of the UVI were around 9 during the summer, though frequently passing this value at the inland measurement stations. The annual accumulated dose of irradiation on a horizontal plane has also been studied, as well as the evolution through the year in units of energy, standard erythemal doses and minimum erythemal doses, according to different phototypes.

Growth of antarctic cyanobacteria under ultraviolet radiation: UVA counteracts UVB inhibition

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

Quesada, A.; Mouget, J.L.; Vincent, W.F.

A mat-forming cyanobacterium (Phormidium murayi West and West) isolated from an ice-shelf pond in Antarctica was grown under white light combined with a range of UVA and UVB irradiance. The 4-day growth rate decreased under increasing ultraviolet (UV) radiation, with a ninefold greater response to UVB relative to UVA. In vivo absorbance spectra showed that UVA and to a greater extent UVB caused a decrease in phycocyanin/chlorophyll a and an increase in carotenoids/chlorophyll a. The phycocyanin/chlorophyll a ratio was closely and positively correlated to the UVB-inhibited growth rate. Under fixed spectral gradients of UV radiation, the growth inhibition effect wasmore » dominated by UVB. However, at specific UVB irradiances the inhibition of growth depended on the ratio of UVB to UVA, and growth rates increased linearly with increasing UVA. These results are consistent with the view that UVB inhibition represents the balance between damage and repair processes that are each controlled by separate wavebands. They also underscore the need to consider UV spectral balance in laboratory and field assays of UVB toxicity. 49 refs., 6 figs.« less

Harmful and favourable ultraviolet conditions for human health over Northern Eurasia

NASA Astrophysics Data System (ADS)

Chubarova, Nataly; Zhdanova, Ekaterina

2014-05-01

We provide the analysis of the spatial and temporal distribution of ultraviolet (UV) radiation over Northern Eurasia taking into account for both its detrimental (erythema and eye-damage effects) and favourable (vitamin D synthesis) influence on human health. The UV effects on six different skin types are considered in order to cover the variety of skin types of European and Asian inhabitants. To better quantifying the vitamin D irradiance threshold we accounted for an open body fraction S as a function of effective air temperature. The spatial and temporal distribution of UV resources was estimated by radiative transfer (RT) modeling (8 stream DISORT RT code) with 1x 1 degree grid and monthly resolution. For this purpose special datasets of main input geophysical parameters (total ozone content, aerosol characteristics, surface UV albedo, UV cloud modification factor) have been created over the territory of Northern Eurasia, which can be of separate interest for the different multidisciplinary scientific applications over the PEEX domain. The new approaches were used to retrieve aerosol and cloud transmittance from different satellite and re-analysis datasets for calculating the solar UV irradiance at ground. Using model simulations and some experimental data we provide the altitude parameterization for different types of biologically active irradiance in mountainous area taking into account not only for the effects of molecular scattering but for the altitude dependence of aerosol parameters and surface albedo. Based on the new classification of UV resources (Chubarova, Zhdanova, 2013) we show that the distribution of harmful (UV deficiency and UV excess) and favorable UV conditions is regulated by various geophysical parameters (mainly, total ozone, cloudiness and open body fraction) and can significantly deviate from latitudinal dependence. The interactive tool for providing simulations of biologically active irradiance and its attribution to the different classes of UV resources is demonstrated. Reference: Natalia Chubarova, Yekaterina Zhdanova. Ultraviolet resources over Northern Eurasia, Photochemistry and Photobiology, Elsevier, 127, 2013, p. 38-51

The S-layer Protein DR_2577 Binds Deinoxanthin and under Desiccation Conditions Protects against UV-Radiation in Deinococcus radiodurans

PubMed Central

Farci, Domenica; Slavov, Chavdar; Tramontano, Enzo; Piano, Dario

2016-01-01

Deinococcus radiodurans has the puzzling ability to withstand over a broad range of extreme conditions including high doses of ultraviolet radiation and deep desiccation. This bacterium is surrounded by a surface layer (S-layer) built of a regular repetition of several proteins, assembled to form a paracrystalline structure. Here we report that the deletion of a main constituent of this S-layer, the gene DR_2577, causes a decrease in the UVC resistance, especially in desiccated cells. Moreover, we show that the DR_2577 protein binds the carotenoid deinoxanthin, a strong protective antioxidant specific of this bacterium. A further spectroscopical characterization of the deinoxanthin-DR_2577 complex revealed features which could suggest a protective role of DR_2577. We propose that, especially under desiccation, the S-layer shields the bacterium from incident ultraviolet light and could behave as a first lane of defense against UV radiation. PMID:26909071

The S-layer Protein DR_2577 Binds Deinoxanthin and under Desiccation Conditions Protects against UV-Radiation in Deinococcus radiodurans.

PubMed

Farci, Domenica; Slavov, Chavdar; Tramontano, Enzo; Piano, Dario

2016-01-01

Deinococcus radiodurans has the puzzling ability to withstand over a broad range of extreme conditions including high doses of ultraviolet radiation and deep desiccation. This bacterium is surrounded by a surface layer (S-layer) built of a regular repetition of several proteins, assembled to form a paracrystalline structure. Here we report that the deletion of a main constituent of this S-layer, the gene DR_2577, causes a decrease in the UVC resistance, especially in desiccated cells. Moreover, we show that the DR_2577 protein binds the carotenoid deinoxanthin, a strong protective antioxidant specific of this bacterium. A further spectroscopical characterization of the deinoxanthin-DR_2577 complex revealed features which could suggest a protective role of DR_2577. We propose that, especially under desiccation, the S-layer shields the bacterium from incident ultraviolet light and could behave as a first lane of defense against UV radiation.

Ultraviolet radiation as disinfection for fish surgical tools

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

Walker, Ricardo W.; Markillie, Lye Meng; Colotelo, Alison HA

Telemetry is frequently used to examine the behavior of fish, and the transmitters used are normally surgically implanted into the coelomic cavity of fish. Implantation requires the use of surgical tools such as scalpels, forceps, needle holders, and sutures. When fish are implanted consecutively, as in large telemetry studies, it is common for surgical tools to be sterilized or, at minimum, disinfected between each use so that pathogens that may be present are not spread among fish. To determine the efficacy for this application, ultraviolet (UV) radiation was used to disinfect surgical tools exposed to one of four aquatic organismsmore » that typically lead to negative health issues for salmonids. These organisms included Aeromonas salmonicida, Flavobacterium psychrophilum, Renibacterium salmoninarum, and Saprolegnia parasitica, causative agents of furunculosis, coldwater disease, bacterial kidney disease, and saprolegniasis (water mold), respectively. Four experiments were conducted to address the question of UV efficacy. In the first experiment, forceps were exposed to the three bacteria at three varying concentrations. After exposure to the bacterial culture, tools were placed into a mobile Millipore UV sterilization apparatus. The tools were then exposed for three different time periods – 2, 5, or 15 min. UV radiation exposures at all durations were effective at killing all three bacteria on forceps at the highest bacteria concentrations. In the second experiment, stab scalpels, sutures, and needle holders were exposed to A. salmonicida using the same methodology as used in Experiment 1. UV radiation exposure at 5 and 15 min was effective at killing A. salmonicida on stab scalpels and sutures but not needle holders. In the third experiment, S. parasitica, a water mold, was tested using an agar plate method and forceps-pinch method. UV radiation was effective at killing the water mold at all three exposure durations. Collectively, this study shows that UV radiation appears to provide a quick alternative disinfection technique to chemical disinfectants (e.g., ethanol) for some surgical tools. However, we do not recommend using this method for tools such as needle holders having overlapping parts or other structures that cannot be exposed directly to UV radiation« less

Enhancements in biologically effective ultraviolet radiation following volcanic eruptions

NASA Technical Reports Server (NTRS)

Vogelmann, A. M.; Ackerman, T. P.; Turco, R. P.

1992-01-01

A radiative transfer model is used to estimate the changes in biologically effective radiation (UV-BE) at the earth's surface produced by the El Chichon (1982) and Mount Pinatubo (1991) eruptions. It is found that in both cases surface intensity can increase because the effect of ozone depletion outweighs the increased scattering.

Formation of the UV Spectrum of Molecular Hydrogen in the Sun

NASA Astrophysics Data System (ADS)

Jaeggli, S. A.; Judge, P. G.; Daw, A. N.

2018-03-01

Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the τ = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550 Å is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.

Pre-harvest UV-C irradiation triggers VOCs accumulation with alteration of antioxidant enzymes and phytohormones in strawberry leaves.

PubMed

Xu, Yanqun; Luo, Zisheng; Charles, Marie Thérèse; Rolland, Daniel; Roussel, Dominique

2017-11-01

Recent studies have highlighted the biological and physiological effects of pre-harvest ultraviolet (UV)-C treatment on growing plants. However, little is known about the involvement of volatile organic compounds (VOCs) and their response to this treatment. In this study, strawberry plants were exposed to three different doses of UV-C radiation for seven weeks (a low dose: 9.6kJm -2 ; a medium dose: 15kJm -2 ; and a high-dose: 29.4kJm -2 ). Changes in VOC profiles were investigated and an attempt was made to identify factors that may be involved in the regulation of these alterations. Principle compounds analysis revealed that VOC profiles of UV-C treated samples were significantly altered with 26 VOCs being the major contributors to segregation. Among them, 18 fatty acid-derived VOCs accumulated in plants that received high and medium dose of UV-C treatments with higher lipoxygenase and alcohol dehydrogenase activities. In treated samples, the activity of the antioxidant enzymes catalase and peroxidase was inhibited, resulting in a reduced antioxidant capacity and higher lipid peroxidation. Simultaneously, jasmonic acid level was 74% higher in the high-dose group while abscisic acid content was more than 12% lower in both the medium and high-dose UV-C treated samples. These results indicated that pre-harvest UV-C treatment stimulated the biosynthesis of fatty acid-derived VOCs in strawberry leaf tissue by upregulating the activity of enzymes of the LOX biosynthetic pathway and downregulating antioxidant enzyme activities. It is further suggested that the mechanisms underlying fatty acid-derived VOCs biosynthesis in UV-C treated strawberry leaves are associated with UV-C-induced changes in phytohormone profiles. Crown Copyright © 2017. Published by Elsevier GmbH. All rights reserved.

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.

Ultraviolet resources over Northern Eurasia.

PubMed

Chubarova, Natalia; Zhdanova, Yekaterina

2013-10-05

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

Characterization of photoluminescence spectra from poly allyl diglycol carbonate (CR-39) upon excitation with the ultraviolet radiation of various wavelengths

NASA Astrophysics Data System (ADS)

El Ghazaly, M.; Al-Thomali, Talal A.

2013-04-01

The induced photoluminescence (PL) from the π-conjugated polymer poly allyl diglycol carbonate (PADC) (CR-39) upon excitation with the ultraviolet radiation of different wavelengths was investigated. The absorption and attenuation coefficients of PADC (CR-39) were recorded using a UV-visible spectrometer. It was found that the absorption and attenuation coefficients of the PADC (CR-39) exhibit a strong dependence on the wavelength of ultraviolet radiation. The PL spectra were measured with a Flormax-4 spectrofluorometer (Horiba). PADC (CR-39) samples were excited by ultraviolet radiation with wavelengths in the range from 260 to 420 nm and the corresponding PL emission bands were recorded. The obtained results show a strong correlation between the PL and the excitation wavelength of ultraviolet radiation. The position of the fluorescence emission band peak was red shifted starting from 300 nm, which was increased with the increase in the excitation wavelength. The PL yield and its band peak height were increased with the increase in the excitation wavelength till 290 nm, thereafter they decreased exponentially with the increase in the ultraviolet radiation wavelength. These new findings should be considered carefully during the use of the PADC (CR-39) in the scientific applications and in using PADC (CR-39) in eyeglasses.

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.

UV-B susceptibility and photoreactivation in embryonic development of the two-spotted spider mite, Tetranychus urticae.

PubMed

Yoshioka, Yoshio; Gotoh, Tetsuo; Suzuki, Takeshi

2018-05-14

Developmental errors are often induced in the embryos of many organisms by environmental stress. Ultraviolet-B radiation (UV-B) is one of the most serious environmental stressors in embryonic development. Here, we investigated susceptibility to UV-B (0.5 kJ m -2 ) in embryos of the two-spotted spider mite, Tetranychus urticae, to examine the potential use of UV-B in control of this important agricultural pest worldwide. Peak susceptibility to UV-B (0% hatchability) was found in T. urticae eggs 36-48 h after oviposition at 25 °C, which coincides with the stages of morphogenesis forming the germ band and initial limb primordia. However, hatchability recovered to ~ 80% when eggs irradiated with UV-B were subsequently exposed to visible radiation (VIS) at 10.2 kJ m -2 , driving photoreactivation (the photoenzymatic repair of DNA damage). The recovery effect decreased to 40-70% hatchability, depending on the embryonic developmental stage, when VIS irradiation was delayed for 4 h after the end of exposure to UV-B. Thus UV-B damage to T. urticae embryos is critical, particularly in the early stages of morphogenesis, and photoreactivation functions to mitigate UV-B damage, even in the susceptible stages, but immediate VIS irradiation is needed after exposure to UV-B. These findings suggest that nighttime irradiation with UV-B can effectively kill T. urticae eggs without subsequent photoreactivation and may be useful in the physical control of this species.

Ultraviolet Light Curves of Gaia16apd in Superluminous Supernova Models

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

Tolstov, Alexey; Zhiglo, Andrey; Nomoto, Ken’ichi

2017-08-10

Observations of Gaia16apd revealed extremely luminous ultraviolet emission among superluminous supernovae (SLSNe). Using radiation hydrodynamics simulations, we perform a comparison of UV light curves, color temperatures, and photospheric velocities between the most popular SLSN models: pair-instability supernova, magnetar, and interaction with circumstellar medium. We find that the interaction model is the most promising to explain the extreme UV luminosity of Gaia16apd. The differences in late-time UV emission and in color evolution found between the models can be used to link an observed SLSN event to the most appropriate model. Observations at UV wavelengths can be used to clarify the naturemore » of SLSNe and more attention should be paid to them in future follow-up observations.« less

Effects of rutin on the physicochemical properties of skin fibroblasts membrane disruption following UV radiation.

PubMed

Dobrzyńska, Izabela; Gęgotek, Agnieszka; Gajko, Ewelina; Skrzydlewska, Elżbieta; Figaszewski, Zbigniew A

2018-02-25

Human skin provides the body's first line of defense against physical and environmental assaults. This study sought to determine how rutin affects the membrane electrical properties, sialic acid content, and lipid peroxidation levels of fibroblast membranes after disruption by ultraviolet (UV) radiation. Changes in cell function may affect the basal electrical surface properties of cell membranes, and changes can be detected by electrokinetic measurements. The charge density of the fibroblast membrane surface was measured as a function of pH. A four-component equilibrium model was used to describe the interaction between ions in solution and ions on the membrane surface. Agreement was found between experimental and theoretical charge variation curves of fibroblast cells between pH 2.5 and 8. Sialic acid content was determined by Svennerholm's resorcinol method, and lipid peroxidation was estimated by measuring the malondialdehyde level. Compared to untreated cells, ultraviolet A (UVA)- or ultraviolet B (UVB)-treated skin cell membranes exhibited higher concentrations of acidic functional groups and higher average association constants with hydroxyl ions, but lower average association constants with hydrogen ions. Moreover, our results showed that UVA and UVB radiation is associated with increased levels of sialic acid and lipid peroxidation products in fibroblasts. Rutin protected cells from some deleterious UV-associated membrane changes, including changes in electrical properties, oxidative state, and biological functions. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental research of digital image correlation system in high temperature test

NASA Astrophysics Data System (ADS)

Chen, Li; Wang, Yonghong; Dan, Xizuo; Xiao, Ying; Yang, Lianxiang

2016-01-01

Digital Image Correlation (DIC) is a full-field technique based on white-light illumination for displacement and strain measurement. But radiation on the specimen surface at high temperature affects the quality of acquired speckle pattern images for traditional DIC measurement. In order to minimize the radiation effect in high temperature measurement, this paper proposes a two-dimensional ultraviolet digital image correlation system (2D UV-DIC) containing UV LED and UV band-pass filter. It is confirmed by experiments that images acquired by this system saturate at higher temperature in comparison with DIC using filtered blue light imaging system. And the UV-DIC remains minimally affected by radiation at the temperature which is nearing the specimen's maximum working temperature (about 1250°C). In addition, considering the heat disturbance that can't be ignored in actual high temperature measurement, this paper also proposes a method using an air controller in combination with image average algorithm, and the method was then used to obtain the thermal expansion coefficient of the Austenitic chromium-nickel stainless steel specimen at different temperatures. By comparing the coefficients with the results calculated by other method, it shows that this comprehensive method has the advantages of strong anti-interference ability and high precision.

RISK ASSESSMENT FOR THE EFFECTS OF SOLAR RADIATION ON AMPHIBIANS

EPA Science Inventory

Recent studies have demonstrated that exposure to solar ultraviolet radiation (UVR) can cause mortality and increase the occurrence of eye and limb malformation in some species of amphibians. Based on these reports and various field observations, it has been hypothesized that UV...