The TROPOMI surface UV algorithm

NASA Astrophysics Data System (ADS)

Lindfors, Anders V.; Kujanpää, Jukka; Kalakoski, Niilo; Heikkilä, Anu; Lakkala, Kaisa; Mielonen, Tero; Sneep, Maarten; Krotkov, Nickolay A.; Arola, Antti; Tamminen, Johanna

2018-02-01

The TROPOspheric Monitoring Instrument (TROPOMI) is the only payload of the Sentinel-5 Precursor (S5P), which is a polar-orbiting satellite mission of the European Space Agency (ESA). TROPOMI is a nadir-viewing spectrometer measuring in the ultraviolet, visible, near-infrared, and the shortwave infrared that provides near-global daily coverage. Among other things, TROPOMI measurements will be used for calculating the UV radiation reaching the Earth's surface. Thus, the TROPOMI surface UV product will contribute to the monitoring of UV radiation by providing daily information on the prevailing UV conditions over the globe. The TROPOMI UV algorithm builds on the heritage of the Ozone Monitoring Instrument (OMI) and the Satellite Application Facility for Atmospheric Composition and UV Radiation (AC SAF) algorithms. This paper provides a description of the algorithm that will be used for estimating surface UV radiation from TROPOMI observations. The TROPOMI surface UV product includes the following UV quantities: the UV irradiance at 305, 310, 324, and 380 nm; the erythemally weighted UV; and the vitamin-D weighted UV. Each of these are available as (i) daily dose or daily accumulated irradiance, (ii) overpass dose rate or irradiance, and (iii) local noon dose rate or irradiance. In addition, all quantities are available corresponding to actual cloud conditions and as clear-sky values, which otherwise correspond to the same conditions but assume a cloud-free atmosphere. This yields 36 UV parameters altogether. The TROPOMI UV algorithm has been tested using input based on OMI and the Global Ozone Monitoring Experiment-2 (GOME-2) satellite measurements. These preliminary results indicate that the algorithm is functioning according to expectations.

Comparison of the efficacy of gamma and UV irradiation in sanitization of fresh carrot juice

NASA Astrophysics Data System (ADS)

Jo, Cheorun; Lee, Kyung Haeng

2012-08-01

As there is no pasteurization procedure for the manufacture of fresh vegetable juice, both industry and consumers have sought a method for improving the storage stability and shelf-life of this category of products. In this study, the effects of commercially available, non-thermal pasteurization processes, such as gamma and UV irradiation, were compared for their efficacy in sanitizing fresh carrot juice (FCJ). FCJ was manufactured, packaged, and gamma irradiated with doses of 0, 1, 3, and 5 kGy. The manufactured FCJ was also passed through 4 UV light lamps at doses of 3.67, 4.69, and 6.50 kGy. The total aerobic bacterial count of the FCJ approached the legal limit (105 CFU/mL) after manufacturing. Both treatments were effective in reducing the number of total aerobic bacteria, and the reduced number was maintained during storage for 7 days. Gamma irradiation was more effective in suppressing microbial growth during storage. When the doses for UV treatment and gamma irradiation were higher, the inactivation effects were higher. The reduction of ascorbic acid content was greater upon gamma irradiation than UV treatment. No difference was found in the contents of flavonoids and polyphenols in FCJ after either treatment. After 3 days of refrigerated storage, the sensory scores of gamma- or UV-irradiated FCJ were superior to those of the control. The results indicate that both non-thermal treatments were effective in improving storage stability and extending shelf-life, but gamma irradiation was slightly better in suppressing microbial growth after treatment.

Amelioration of ultraviolet-induced photokeratitis in mice treated with astaxanthin eye drops.

PubMed

Lennikov, Anton; Kitaichi, Nobuyoshi; Fukase, Risa; Murata, Miyuki; Noda, Kousuke; Ando, Ryo; Ohguchi, Takeshi; Kawakita, Tetsuya; Ohno, Shigeaki; Ishida, Susumu

2012-01-01

Ultraviolet (UV) acts as low-dose ionizing radiation. Acute UVB exposure causes photokeratitis and induces apoptosis in corneal cells. Astaxanthin (AST) is a carotenoid, present in seafood, that has potential clinical applications due to its high antioxidant activity. In the present study, we examined whether topical administration of AST has preventive and therapeutic effects on UV-photokeratitis in mice. C57BL/6 mice were administered with AST diluted in polyethylene glycol (PEG) in instillation form (15 μl) to the right eye. Left eyes were given vehicle alone as controls. Immediately after the instillation, the mice, under anesthesia, were irradiated with UVB at a dose of 400 mJ/cm². Eyeballs were collected 24 h after irradiation and stained with H&E and TUNEL. In an in vitro study, mouse corneal epithelial (TKE2) cells were cultured with AST before UV exposure to quantify the UV-derived cytotoxicity. UVB exposure induced cell death and thinning of the corneal epithelium. However, the epithelium was morphologically well preserved after irradiation in AST-treated corneas. Irradiated corneal epithelium was significantly thicker in eyes treated with AST eye drops, compared to those treated with vehicles (p<0.01), in a doses dependent manner. Significantly fewer apoptotic cells were observed in AST-treated eyes than controls after irradiation (p<0.01). AST also reduced oxidative stress in irradiated corneas. The in vitro study showed less cytotoxicity of TKE2 cells in AST-treated cultures after UVB-irradiation (p<0.01). The cytoprotective effect increased with the dose of AST. Topical AST administration may be a candidate treatment to limit the damages by UV irradiation with wide clinical applications.

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli.

PubMed

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of [14C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60Co gamma-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of gamma-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after higher doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m-2) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as gamma-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

Effect of UV irradiation on organic matter extracted from treated Ohio River water studied through the use of electrospray mass spectrometry.

PubMed

Magnuson, Matthew L; Kelty, Catherine A; Sharpless, Charles M; Linden, Karl G; Fromme, William; Metz, Deborah H; Kashinkunti, Ramesh

2002-12-01

Ohio River water was treated by settling, sand filtration, and granular activated carbon filtration. It was then irradiated by low-pressure (monochromatic) and medium-pressure (polychromatic) UV lamps to investigate the effects of UV irradiation on the extracted organic matter (EOM). When the EOM, collected by solid phase extraction cartridges, was analyzed by conventional UV spectroscopy and size exclusion chromatography (SEC), no significant changes in the EOM were revealed for various UV doses. Positive and negative electrospray ionization mass spectrometry (ESI-MS) of the EOM produced mass spectra that vary significantly with UV dose. The UV dosage conditions also appear to affect the reactivity of the EOM to subsequent chlorination. The magnitude of the spectral changes is generally greater for medium-pressure lamps than for low pressure and increases with UV exposure. Based on the observed MS peaks, the changes may be due to the presence of lignin, resulting perhaps from photooxidation and/or photo rearrangement of macromolecules in the sample. When chlorination is used for secondary disinfection, these results suggest that it may be important to consider the effects of UV irradiation on the organic matter in the water before applying UV disinfection technology to a particular source water.

Effect of UV irradiation on aflatoxin reduction: a cytotoxicity evaluation study using human hepatoma cell line.

PubMed

Patras, Ankit; Julakanti, Sharath; Yannam, Sudheer; Bansode, Rishipal R; Burns, Mallory; Vergne, Matthew J

2017-11-01

In this proof-of-concept study, the efficacy of a medium-pressure UV (MPUV) lamp source to reduce the concentrations of aflatoxin B 1 , aflatoxin B 2 , and aflatoxin G 1 (AFB 1, AFB 2 , and AFG 1 ) in pure water is investigated. Irradiation experiments were conducted using a collimated beam system operating between 200 to 360 nm. The optical absorbance of the solution and the irradiance of the lamp are considered in calculating the average fluence rate. Based on these factors, the UV dose was quantified as a product of average fluence rate and treatment time. Known concentrations of aflatoxins were spiked in water and irradiated at UV doses ranging from 0, 1.22, 2.44, 3.66, and 4.88 J cm -2 . The concentration of aflatoxins was determined by HPLC with fluorescence detection. LC-MS/MS product ion scans were used to identify and semi-quantify degraded products of AFB 1 , AFB 2 , and AFG 1 . It was observed that UV irradiation significantly reduced aflatoxins in pure water (p < 0.05). Irradiation doses of 4.88 J cm -2 reduced concentrations 67.22% for AFG 1 , 29.77% for AFB 2 , and 98.25% for AFB 1 (p < 0.05). Using this technique, an overall reduction of total aflatoxin content of ≈95% (p < 0.05) was achieved. We hypothesize that the formation of ˙OH radicals initiated by UV light may have caused photolysis of AFB 1 , AFB 2 , and AFG 1 molecules. In cell culture studies, our results demonstrated that the increase of UV dosage decreased the aflatoxin-induced cytotoxicity in HepG 2 cells. Therefore, our research finding suggests that UV irradiation can be used as an effective technique for the reduction of aflatoxins.

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

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

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

1975-08-01

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

Characterization and optical studies of 90/10 (wt/wt%) PVA/β-chitin blend irradiated with γ-rays.

PubMed

Abd El-Kader, F H; Gaafer, S A; Abd El-Kader, M F H

2014-10-15

X-ray diffraction, IR spectroscopy and UV/visible spectra were studied as a function of gamma irradiation doses (5-100kGy) for 90/10 (wt/wt%) PVA/β-chitin. A new intense reflection peak at 2θ=21.5° appeared in the X-ray spectrum of the sample irradiated at 50kGy γ-dose. Besides, the band centered at 2931cm(-1) in IR spectrum splits into two clearly separated bands around 2919 and 2941cm(-1) for the sample irradiated at 10kGy γ-dose. The disappearance of the absorption band at 280nm of PVA in the blend sample indicates that the ligand PVA becomes opaque in the UV region and provides evidence for the miscibility between homopolymers. The value of absorbance, in UV/visible range, at 10kGy γ-dose was the highest one compared to the other γ-doses. The location of the γ-doses on the chromaticity diagram was different, indicating the change in the spectral colors of the investigated blend. In addition, the absorption edge, band tail and color parameters values were determined as a function of γ-doses. Copyright © 2014 Elsevier B.V. All rights reserved.

Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

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

Feister, Uwe; Meyer, Gabriele; Kirst, Ulrich

2013-05-10

Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels.more » The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.« less

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

PubMed Central

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

2015-01-01

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

A phase II randomized placebo-controlled trial of oral N-acetylcysteine for protection of melanocytic nevi against UV-induced oxidative stress in vivo

PubMed Central

Cassidy, Pamela B.; Liu, Tong; Florell, Scott R.; Honeggar, Matthew; Leachman, Sancy A.; Boucher, Kenneth M.; Grossman, Douglas

2016-01-01

Oxidative stress plays a role in UV-induced melanoma, which may arise from melanocytic nevi. We investigated whether oral administration of the antioxidant N-acetylcysteine (NAC) could protect nevi from oxidative stress in vivo in the setting of acute UV exposure. The minimal erythemal dose (MED) was determined for 100 patients at increased risk for melanoma. Patients were randomized to receive a single dose (1200 mg) of NAC or placebo, in double-blind fashion, and then one nevus was irradiated (1–2 MED) using a solar simulator. One day later, the MED was re-determined and the irradiated nevus and a control un-irradiated nevus were removed for histologic analysis and examination of biomarkers of NAC metabolism and UV-induced oxidative stress. Increased expression of 8-oxoguanine, thioredoxin reductase-1, and γ-glutamylcysteine synthase modifier subunit were consistently seen in UV-treated compared to unirradiated nevi. However, no significant differences were observed in these UV-induced changes or in the pre- and post-intervention MED between those patients receiving NAC vs. placebo. Similarly, no significant differences were observed in UV-induced changes between subjects with germline wild-type vs. loss of function mutations in the melanocortin-1 receptor. Nevi showed similar changes of UV-induced oxidative stress in an open-label post-trial study in 10 patients who received NAC 3 h before nevus irradiation. Thus a single oral dose of NAC did not effectively protect nevi from UV-induced oxidative stress under the conditions examined. PMID:27920018

Assessment of the breakdown products of solar/UV induced photolytic degradation of food dye tartrazine.

PubMed

dos Santos, Tuane Cristina; Zocolo, Guilherme Julião; Morales, Daniel Alexandre; Umbuzeiro, Gisela de Aragão; Zanoni, Maria Valnice Boldrin

2014-06-01

The food dye tartrazine (CI 19140) was exposed to UV irradiation from an artificial source, a mercury vapor lamp, and a natural one, sunlight. It was observed that conditions such as energy dose, irradiation time, pH and initial dye concentration affected its discoloration. There was 100% of color removal, after 30min of irradiation, when a dye solution 1×10(-5)molL(-1) was submitted to an energy dose of 37.8Jcm(-2). Liquid Chromatography coupled to Diode Array Detection and Mass Spectrometry confirmed the cleavage of the chromophore group and the formation of five by-products at low concentration. Although by-products were formed, the Salmonella/microsome mutagenicity assay performed for both, the dye solution at a dose of 5.34mg/plate and the solutions obtained after exposure to UV irradiation, did not present mutagenic activity for TA98 and TA100 with and without S9. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dietary Milk Sphingomyelin Prevents Disruption of Skin Barrier Function in Hairless Mice after UV-B Irradiation.

PubMed

Oba, Chisato; Morifuji, Masashi; Ichikawa, Satomi; Ito, Kyoko; Kawahata, Keiko; Yamaji, Taketo; Asami, Yukio; Itou, Hiroyuki; Sugawara, Tatsuya

2015-01-01

Exposure to ultraviolet-B (UV-B) irradiation causes skin barrier defects. Based on earlier findings that milk phospholipids containing high amounts of sphingomyelin (SM) improved the water content of the stratum corneum (SC) in normal mice, here we investigated the effects of dietary milk SM on skin barrier defects induced by a single dose of UV-B irradiation in hairless mice. Nine week old hairless mice were orally administrated SM (146 mg/kg BW/day) for a total of ten days. After seven days of SM administration, the dorsal skin was exposed to a single dose of UV-B (20 mJ/cm2). Administration of SM significantly suppressed an increase in transepidermal water loss and a decrease in SC water content induced by UV-B irradiation. SM supplementation significantly maintained covalently-bound ω-hydroxy ceramide levels and down-regulated mRNA levels of acute inflammation-associated genes, including thymic stromal lymphopoietin, interleukin-1 beta, and interleukin-6. Furthermore, significantly higher levels of loricrin and transglutaminase-3 mRNA were observed in the SM group. Our study shows for the first time that dietary SM modulates epidermal structures, and can help prevent disruption of skin barrier function after UV-B irradiation.

Ultraviolet radiation in the Atacama Desert.

PubMed

Cordero, R R; Damiani, A; Jorquera, J; Sepúlveda, E; Caballero, M; Fernandez, S; Feron, S; Llanillo, P J; Carrasco, J; Laroze, D; Labbe, F

2018-03-31

The world's highest levels of surface ultraviolet (UV) irradiance have been measured in the Atacama Desert. This area is characterized by its high altitude, prevalent cloudless conditions, and a relatively low total ozone column. In this paper, we provide estimates of the surface UV (monthly UV index at noon and annual doses of UV-B and UV-A) for all sky conditions in the Atacama Desert. We found that the UV index at noon during the austral summer is expected to be greater than 11 in the whole desert. The annual UV-B (UV-A) doses were found to range from about 3.5 kWh/m 2 (130 kWh/m 2 ) in coastal areas to 5 kWh/m 2 (160 kWh/m 2 ) on the Andean plateau. Our results confirm significant interhemispherical differences. Typical annual UV-B doses in the Atacama Desert are about 40% greater than typical annual UV-B doses in northern Africa. Mostly due to seasonal changes in the ozone, the differences between the Atacama Desert and northern Africa are expected to be about 60% in the case of peak UV-B levels (i.e. the UV-B irradiances at noon close to the summer solstice in each hemisphere). Interhemispherical differences in the UV-A are significantly lower since the effect of the ozone in this part of the spectrum is minor.

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

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

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

1981-01-01

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

Transformation of Saccharomyces cerevisiae with UV-irradiated single-stranded plasmid.

PubMed

Zgaga, Z

1991-08-01

UV-irradiated single-stranded replicative plasmids were used to transform different yeast strains. The low doses of UV used in this study (10-75 J/m2) caused a significant decrease in the transforming efficiency of plasmid DNA in the Rad+ strain, while they had no effect on transformation with double-stranded plasmids of comparable size. Neither the rev3 mutation, nor the rad18 or rad52 mutations influenced the efficiency of transformation with irradiated single-stranded plasmid. However, it was found to be decreased in the double rev3 rad52 mutant. Extracellular irradiation of plasmid that contains both URA3 and LEU2 genes (psLU) gave rise to up to 5% Leu- transformants among selected Ura+ ones in the repair-proficient strain. Induction of Leu- transformants was dose-dependent and only partially depressed in the rev3 mutant. These results suggest that both mutagenic and recombinational repair processes operate on UV-damaged single-stranded DNA in yeast.

[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.

Efficiency of ocular UV protection by clear lenses

PubMed Central

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

2018-01-01

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

Efficiency of ocular UV protection by clear lenses.

PubMed

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

2018-04-01

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

Seasonal and diurnal variations in Martian surface ultraviolet irradiation: biological and chemical implications for the Martian regolith

NASA Astrophysics Data System (ADS)

Patel, M. R.; Bérces, A.; Kolb, C.; Lammer, H.; Rettberg, P.; Zarnecki, J. C.; Selsis, F.

2003-01-01

The issue of the variation of the surface ultraviolet (UV) environment on Mars was investigated with particular emphasis being placed on the interpretation of data in a biological context. A UV model has been developed to yield the surface UV irradiance at any time and place over the Martian year. Seasonal and diurnal variations were calculated and dose rates evaluated. Biological interpretation of UV doses is performed through the calculation of DNA damage effects upon phage T7 and Uracil, used as examples for biological dosimeters. A solar UV "hotspot" was revealed towards perihelion in the southern hemisphere, with a significant damaging effect upon these species. Diurnal profiles of UV irradiance are also seen to vary markedly between aphelion and perihelion. The effect of UV dose is also discussed in terms of the chemical environment of the Martian regolith, since UV irradiance can reach high enough levels so as to have a significant effect upon the soil chemistry. We show, by assuming that H2O is the main source of hydrogen in the Martian atmosphere, that the stoichiometrically desirable ratio of 2:1 for atmospheric H and O loss rates to space are not maintained and at present the ratio is about 20:1. A large planetary oxygen surface sink is therefore necessary, in contrast with escape to space. This surface oxygen sink has important implications for the oxidation potential and the toxicology of the Martian soil. UV-induced adsorption of O_{2}^{-} super-radicals plays an important role in the oxidative environment of the Martian surface, and the biologically damaging areas found in this study are also shown to be regions of high subsurface oxidation. Furthermore, we briefly cover the astrobiological implications for landing sites that are planned for future Mars missions

Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines.

PubMed

Zakaria, Fiona; Harelimana, Bertin; Ćurko, Josip; van de Vossenberg, Jack; Garcia, Hector A; Hooijmans, Christine Maria; Brdjanovic, Damir

2016-01-01

Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.

Effects of gamma radiation on commercial food packaging films—study of changes in UV/VIS spectra

NASA Astrophysics Data System (ADS)

Moura, E. A. B.; Ortiz, A. V.; Wiebeck, H.; Paula, A. B. A.; Silva, A. L. A.; Silva, L. G. A.

2004-09-01

The effects of gamma irradiation doses up to 100 kGy on the optical properties of different commercial packaging films were studied in this paper. The packaging films analyzed were: polyethylene "LDPE", amide 6-amide 6.6 copolymer "PA6-PA6.6" and poly(ethylene terephthalate) "PET". An investigation on film samples before and after irradiation was performed by UV/VIS spectroscopy. The results showed that, in the absorption spectra of irradiated LDPE and PA6-PA6.6 films, a red-shift in the wavelength of the UV cutoff and a marked reduction in % transmittance (at low wavelengths) occur with increasing radiation dose. With respect to PET samples, no significant changes were observed in either light absorption or transmittance.

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

PubMed

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

2015-05-01

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

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.

Simulation study of natural UV-B radiation on Catla catla and its impact on physiology, oxidative stress, Hsp 70 and DNA fragmentation.

PubMed

Singh, Moirangthem Kameshwor; Sharma, Jai Gopal; Chakrabarti, Rina

2015-08-01

UV-B radiation is a potential stressor to the aquacultural species. Catla catla, catla larvae (1.08±0.065g) were exposed to different doses of UV-B radiation, 0 (control), 504, 1008, 1512 and 2016mJ/cm(2) at a mean radiant energy of 80μW/cm(2) for 21days. The dose of UV-B radiation was selected on the basis of the field study conducted in Lake Naini, Delhi, India (Latitude: 28°41'26″N and Longitude: 77°12″37″E). Significantly (P<0.05) lower survival, average weight and specific growth rate were found in UV-B irradiated larvae compared to the control one. Food conversion ratio was 1.5-4-fold higher in UV-B treated larvae compared to the control one. The carbonyl protein (CP), thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD) levels were significantly (P <0.05) higher in UV-B irradiated larvae compared to the control group. Among the treated larvae, CP and SOD were significantly (P <0.05) higher in larvae exposed at 1512mJ/cm(2) UV-B. A correlation was found between the CP and SOD (R(2)=0.834). Highest TBARS level was found in 2016mJ/cm(2) UV-B exposed catla. Nitric oxide synthase level was significantly (P <0.05) lower in UV-B exposed larvae compared to the control one. A 3-fold increased Hsp 70 level was recorded in UV-B irradiated catla compared to the control larvae. Comet assay analysis indicated that UV-B irradiation enhanced DNA fragmentation. Tail extent moment and the olive tail moment were significantly (P <0.05) higher in 2016mJ/cm(2) UV-B exposed catla compared to others. The tail length was significantly (P <0.05) higher in 1512 and 2016mJ/cm(2) UV-B exposed larvae compared to the other doses. The present study suggests that the catla is a useful species for the biomonitoring of stress in the aquatic environment. Copyright © 2015 Elsevier B.V. All rights reserved.

[Oligonucleotide derivatives in the nucleic acid hybridization analysis. I. Covalent immobilization of oligonucleotide probes onto the nylon].

PubMed

Dmitrienko, E V; Pyshnaia, I A; Pyshnyĭ, D V

2010-01-01

The features of UV-induced immobilization of oligonucleotides on a nylon membranes and the effectiveness of enzymatic labeling of immobilized probes at heterophase detection of nucleic acids are studied. Short terminal oligothymidilate (up to 10 nt) sequences are suggested to attach to the probe via a flexible ethylene glycol based linker. The presence of such fragment enhances the intensity of immobilization and reduces UV-dependent degradation of the targeted (sequence-specific) part of the probe by reducing the dose needed for the immobilization of DNA. The optimum dose of UV-irradiation is determined to be ~0.4 J/cm(2) at the wavelength 254 nm. This dose provides high level of hybridization signal for immobilized probes with various nucleotide composition of the sequence specific moiety. The amide groups of the polyamide are shown to play the key role in the photoinduced immobilization of nucleic acids, whereas the primary amino groups in the structure of PA is not the center responsible for the covalent binding of DNA by UV-irradiation, as previously believed. Various additives in the soaking solution during the membrane of UV-dependent immobilization of probes are shown to influence its effectiveness. The use of alternative to UV-irradiation system of radical generation are shown to provide the immobilization of oligonucleotides onto the nylon membrane.

Acute UV irradiation increases heparan sulfate proteoglycan levels in human skin.

PubMed

Jung, Ji-Yong; Oh, Jang-Hee; Kim, Yeon Kyung; Shin, Mi Hee; Lee, Dayae; Chung, Jin Ho

2012-03-01

Glycosaminoglycans are important structural components in the skin and exist as various proteoglycan forms, except hyaluronic acid. Heparan sulfate (HS), one of the glycosaminoglycans, is composed of repeated disaccharide units, which are glucuronic acids linked to an N-acetyl-glucosamine or its sulfated forms. To investigate acute ultraviolet (UV)-induced changes of HS and HS proteoglycans (HSPGs), changes in levels of HS and several HSPGs in male human buttock skin were examined by immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR) after 2 minimal erythema doses (MED) of UV irradiation (each n = 4-7). HS staining revealed that 2 MED of UV irradiation increased its expression, and staining for perlecan, syndecan-1, syndecan-4, CD44v3, and CD44 showed that UV irradiation increased their protein levels. However, analysis by real-time qPCR showed that UV irradiation did not change mRNA levels of CD44 and agrin, and decreased perlecan and syndecan-4 mRNA levels, while increased syndecan-1 mRNA level. As HS-synthesizing or -degrading enzymes, exostosin-1 and heparanase mRNA levels were increased, but exostosin-2 was decreased by UV irradiation. UV-induced matrix metalloproteinase-1 expression was confirmed for proper experimental conditions. Acute UV irradiation increases HS and HSPG levels in human skin, but their increase may not be mediated through their transcriptional regulation.

Reconstruction of daily solar UV irradiation from 1893 to 2002 in Potsdam, Germany

NASA Astrophysics Data System (ADS)

Junk, Jürgen; Feister, Uwe; Helbig, Alfred

2007-08-01

Long-term records of solar UV radiation reaching the Earth’s surface are scarce. Radiative transfer calculations and statistical models are two options used to reconstruct decadal changes in solar UV radiation from long-term records of measured atmospheric parameters that contain information on the effect of clouds, atmospheric aerosols and ground albedo on UV radiation. Based on earlier studies, where the long-term variation of daily solar UV irradiation was derived from measured global and diffuse irradiation as well as atmospheric ozone by a non-linear regression method [Feister et al. (2002) Photochem Photobiol 76:281 293], we present another approach for the reconstruction of time series of solar UV radiation. An artificial neural network (ANN) was trained with measurements of solar UV irradiation taken at the Meteorological Observatory in Potsdam, Germany, as well as measured parameters with long-term records such as global and diffuse radiation, sunshine duration, horizontal visibility and column ozone. This study is focussed on the reconstruction of daily broad-band UV-B (280 315 nm), UV-A (315 400 nm) and erythemal UV irradiation (ER). Due to the rapid changes in cloudiness at mid-latitude sites, solar UV irradiance exhibits appreciable short-term variability. One of the main advantages of the statistical method is that it uses doses of highly variable input parameters calculated from individual spot measurements taken at short time intervals, which thus do represent the short-term variability of solar irradiance.

Study on γH2AX Expression of Lymphocytes as a Biomarker In Radiation Biodosimetry

PubMed Central

Pan, Yan; Gao, Gang; Ruan, Jian Lei; Liu, Jian Xiang

2016-01-01

Flow cytometry analysis was used to detect the changes of γH2AX protein expression in human peripheral blood lymphocytes. In the dose-effect study, the expression of γH2AX was detected 1 h after irradiation with 60Co γ-rays at doses of 0, 0.5, 1, 2, 4, and 6 Gy. Blood was cultivated for 0, 1, 2, 4, 6, 12, and 24 h after 4 Gy 60Co γ-rays irradiation for the time-effect study. At the same time, the blood was divided into four treatment groups (ultraviolet [UV] irradiation, 60Co γ-rays irradiation, UV plus 60Co γ-rays irradiation, and control group) to detect the changes of protein expression of γH2AX. The results showed that the γH2AX protein expression was in dose-effect and time-effect relationship with 60Co γ-rays. The peak expression of γH2AX was at 1 h after 60Co γ-ray irradiation and began to decrease quickly. Compared to irradiation with 60Co γ-rays alone, the expression of γH2AX was not significantly changed after irradiation with 60Co γ-rays plus UV. Dose rate did not significantly change the expression of γH2AX. The expression of γH2AX induced by 60Co γ-rays was basically consistent with the mice in vivo and in vitro. The results revealed that the detection of γH2AX protein expression changes in peripheral blood lymphocyte by flow cytometry analysis is reasonable and may be useful for biodosimetry. PMID:28217286

Study on performances of colorless and transparent shape memory polyimide film in space thermal cycling, atomic oxygen and ultraviolet irradiation environments

NASA Astrophysics Data System (ADS)

Gao, Hui; Lan, Xin; Liu, Liwu; Xiao, Xinli; Liu, Yanju; Leng, Jinsong

2017-09-01

Shape memory polymers with high glass transition temperature (HSMPs) and HSMP-based deployable structures and devices, which can bear harsh operation conditions for durable applications, have attracted more and more interest in recent years. In this article, colorless and transparent shape memory polyimide (SMCTPI) films were subjected to simulated vacuum thermal cycling, atomic oxygen (AO) and ultraviolet (UV) irradiation environments up to 600 h, 556 h and 600 h for accelerated irradiation. The glass transition temperature (Tg) determined by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) had no obvious changes after being irradiated by varying amounts of thermal cycling, AO and UV irradiation dose. After being irradiated by 50 thermal cycles, 10 × 1021 atoms cm-2 AO irradiation and 3000 ESH UV irradiation, shape recovery behaviors of SMCTPI films also had no obvious damage even if they experienced 30 shape memory cycles, while the surface morphologies and optical properties were seriously destroyed by AO irradiation, as compared with thermal cycling and UV irradiation. The tensile strength could separately maintain 122 MPa, 120 MPa and 70 MPa after 50 thermal cycles, 10 × 1021 atoms cm-2 AO irradiation and 3000 ESH UV irradiation, which shows great potential for use in aerospace structures and devices.

UV irradiation and autoclave treatment for elimination of contaminating DNA from laboratory consumables.

PubMed

Gefrides, Lisa A; Powell, Mark C; Donley, Michael A; Kahn, Roger

2010-02-01

Laboratories employ various approaches to ensure that their consumables are free of DNA contamination. They may purchase pre-treated consumables, perform quality control checks prior to casework, and use in-house profile databases for contamination detection. It is better to prevent contamination prior to DNA typing than identify it after samples are processed. To this end, laboratories may UV irradiate or autoclave consumables prior to use but treatment procedures are typically based on killing microorganisms and not on the elimination of DNA. We report a systematic study of UV and autoclave treatments on the persistence of DNA from saliva. This study was undertaken to determine the best decontamination strategy for the removal of DNA from laboratory consumables. We have identified autoclave and UV irradiation procedures that can eliminate nanogram quantities of contaminating DNA contained within cellular material. Autoclaving is more effective than UV irradiation because it can eliminate short fragments of contaminating DNA more effectively. Lengthy autoclave or UV irradiation treatments are required. Depending on bulb power, a UV crosslinker may take a minimum of 2h to achieve an effective dose for elimination of nanogram quantities of contaminating DNA (>7250mJ/cm(2)). Similarly autoclaving may also take 2h to eliminate similar quantities of contaminating DNA. For this study, we used dried saliva stains to determine the effective dose. Dried saliva stains were chosen because purified DNA as well as fresh saliva are less difficult to eradicate than dried stains and also because consumable contamination is more likely to be in the form of a collection of dry cells.

Evaluation of disinfection by-product formation during chlor(am)ination from algal organic matter after UV irradiation.

PubMed

Chen, Shi; Deng, Jing; Li, Lei; Gao, Naiyun

2018-02-01

This study evaluated the effect of low-pressure ultraviolet (UV) irradiation on the formation of disinfection by-products (DBPs) from algal organic matter of Microcystis aeruginosa during subsequent chlorination and chloramination. The algal organic matter includes extracellular organic matter (EOM) and intracellular organic matter (IOM). The fluorescence excitation-emission matrix spectra indicated that the humic/fulvic acid-like organics of EOM and the protein-like organics of IOM may be preferentially degraded by UV treatment. UV irradiation with low specific UV absorbance values was effective in reducing the formation of trihalomethanes and dichloroacetic acid from EOM and IOM during the subsequent chlorination. During the UV-chloramine process, higher UV dose (1000 mJ/cm 2 ) led to the decrease of the formation of dichloroacetic acid, trichloroacetic acid, and haloketones from IOM by an average of 24%. Furthermore, UV irradiation can slightly increase the bromine substitution factors (BSFs) of haloacetic acids from EOM during chlorination, including dihaloacetic acids and trihaloacetic acids in the presence of bromide (50 μg/L). However, UV irradiation did not shift the formation of DBPs from IOM to more brominated species, since the BSFs of trihalomethanes, dihaloacetic acids, trihaloacetic acids, and dihaloacetonitriles almost kept unchanged during UV-chlorine process. As for UV-chloramine process, UV irradiation decreased the BSFs of trihalomethanes, while increased the BSFs of dihaloacetic acid for both EOM and IOM. Overall, the UV pretreatment process is a potential technology in treating algae-rich water.

Impact on Vitamin D2, Vitamin D4 and Agaritine in Agaricus bisporus Mushrooms after Artificial and Natural Solar UV Light Exposure.

PubMed

Urbain, Paul; Valverde, Juan; Jakobsen, Jette

2016-09-01

Commercial mushroom production can expose mushrooms post-harvest to UV light for purposes of vitamin D2 enrichment by converting the naturally occurring provitamin D2 (ergosterol). The objectives of the present study were to artificially simulate solar UV-B doses occurring naturally in Central Europe and to investigate vitamin D2 and vitamin D4 production in sliced Agaricus bisporus (button mushrooms) and to analyse and compare the agaritine content of naturally and artificially UV-irradiated mushrooms. Agaritine was measured for safety aspects even though there is no rationale for a link between UV light exposure and agaritine content. The artificial UV-B dose of 0.53 J/cm(2) raised the vitamin D2 content to significantly (P < 0.001) higher levels of 67.1 ± 9.9 μg/g dry weight (DW) than sun exposure (3.9 ± 0.8 μg/g dry DW). We observed a positive correlation between vitamin D4 and vitamin D2 production (r(2) = 0.96, P < 0.001) after artificial UV irradiation, with vitamin D4 levels ranging from 0 to 20.9 μg/g DW. The agaritine content varied widely but remained within normal ranges in all samples. Irrespective of the irradiation source, agaritine dropped dramatically in conjunction with all UV-B doses both artificial and natural solar, probably due to its known instability. The biological action of vitamin D from UV-exposed mushrooms reflects the activity of these two major vitamin D analogues (D2, D4). Vitamin D4 should be analysed and agaritine disregarded in future studies of UV-exposed mushrooms.

Photostabilization of butyl methoxydibenzoylmethane (Avobenzone) and ethylhexyl methoxycinnamate by bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), a new UV broadband filter.

PubMed

Chatelain, E; Gabard, B

2001-09-01

It is now well documented that chronic UVA exposure induces damage to human skin. Therefore, modern sunscreens should not only provide protection from both UVB and UVA radiation but also maintain this protection during the entire period of exposure to the sun. UVA filters, however, are rare and not sufficiently photostable. We investigated the effect of the introduction of a new UV filter, bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), in oil in water sunscreen formulations on the photostability of butyl methoxydibenzoylmethane (Avobenzone [AVB]) after irradiation with an optically filtered Xenon arc source (UV irradiance adjusted at 1 mean effective dose [MED]/min). With spectrophotometrical methods to assess the sun protection factor (SPF) and UVA ratio and chromatographical methods to determine the amount of UV filters recovered after irradiation we showed that Tinosorb S prevented the photodegradation of AVB in a concentration-dependent way, leading to a sustained SPF and UVA ratio even after irradiation with doses of up to 30 MED. Since AVB was shown to destabilize ethylhexyl methoxycinnamate (EHM) we tested the effect of Tinosorb S in sunscreens containing this UV filter combination. Here too Tinosorb S showed photoprotective properties toward both UV filters. Thus, Tinosorb S can be used successfully to improve the photostability and efficiency of sunscreens containing AVB and EHM.

The effect of UV-B radiation on Bufo arenarum embryos survival and superoxide dismutase activity.

PubMed

Herkovits, J; D'Eramo, J L; Fridman, O

2006-03-01

The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m(2) resulted in 100% lethality within 24 hr while 820 Joule/m(2) was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m(2) at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 +/- 14.29, 74.5 +/- 13.19, 39.5 +/- 6.99 and 10.7 +/- 1.89 respectively while for control embryos it was 10.88 +/- 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure.

Invasion and initial replication of ultraviolet irradiated waterborne infective stages of Myxobolus cerebralis results in immunity to whirling disease in rainbow trout.

PubMed

Hedrick, Ronald P; McDowell, Terry S; Adkison, Mark A; Myklebust, Karin A; Mardones, Fernando O; Petri, Brian

2012-06-01

Myxobolus cerebralis is a microscopic metazoan parasite (Phylum Myxozoa: Myxosporea) associated with salmonid whirling disease. There are currently no vaccines to minimise the serious negative economical and ecological impacts of whirling disease among populations of salmonid fish worldwide. UV irradiation has been shown to effectively inactivate the waterborne infective stages or triactinomyxons of M. cerbralis in experimental and hatchery settings but the mechanisms by which the parasite is compromised are unknown. Treatments of triactinomyxons with UV irradiation at doses from 10 to 80 mJ/cm(2) either prevented (20-80 mJ/cm(2)) or significantly inhibited (10 mJ/cm(2)) completion of the parasite life cycle in experimentally exposed juvenile rainbow trout (Oncorhynchus mykiss). However, even the highest doses of UV irradiation examined (80 mJ/cm(2)) did not prevent key steps in the initiation of parasite infection, including attachment and penetration of the epidermis of juvenile rainbow trout as demonstrated by scanning electron and light microscopy. Furthermore, replication of UV-treated parasites within the first 24h following invasion of the caudal fin was suggested by the detection of concentrations of parasite DNA by quantitative PCR comparable to that among fish exposed to an equal concentration of untreated triactinomyxons. Subsequent development of parasites treated with an 80 mJ/cm(2) dose of UV irradiation however, was impaired as demonstrated by the decline and then lack of detection of parasite DNA; a trend beginning at 10 days and continuing thereafter until the end of the study at 46 days post parasite exposure. Treatments of triactinomyxons with a lower dose of UV irradiation (20 mJ/cm(2)) resulted in a more prolonged survival with parasite DNA detected, although at very low concentrations, in fish up to 49 days post parasite exposure. The successful invasion but only short-term survival of parasites treated with UV in rainbow trout resulted in a protective response to challenges with fully infective triactinomyxons. Prior treatments of juvenile rainbow trout with UV-treated triactinomyxons (10 and 20 mJ/cm(2)) resulted in a reduced prevalence of infection and significantly lower concentrations of cranial myxospores (two direct measures of the severity of whirling disease) compared with trout receiving no prior treatments when assessed 5 months post parasite exposure to fully infective triactinomyxons. Copyright © 2012 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

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.

Protective effects of a topical antioxidant mixture containing vitamin C, ferulic acid, and phloretin against ultraviolet-induced photodamage in human skin.

PubMed

Oresajo, Christian; Stephens, Thomas; Hino, Peter D; Law, Robert M; Yatskayer, Margarita; Foltis, Peter; Pillai, Sreekumar; Pinnell, Sheldon R

2008-12-01

Ultraviolet (UV) irradiation of the skin leads to acute inflammatory reactions, such as erythema, sunburn, and chronic reactions, including premature skin aging and skin cancer. In this study, the effects of a topical antioxidant mixture consisting of vitamin C, ferulic acid, and phloretin on attenuating the harmful effects of UV irradiation on normal healthy volunteers were studied using biomarkers of skin damage. Ten subjects (age, 18-60 years; Fitzpatrick skin types II and III) were randomized and treated with antioxidant product or vehicle control on the lower back for four consecutive days. On day 3, the minimal erythema dose (MED) was determined for each subject at a different site on the back. On day 4, the two test sites received solar-simulated UV irradiation 1-5x MED at 1x MED intervals. On day 5, digital images were taken, and 4-mm punch biopsies were collected from the two 5x MED test sites and a control site from each subject for morphology and immunohistochemical studies. UV irradiation significantly increased the erythema of human skin in a linear manner from 1x to 5x MED. As early as 24 h after exposure to 5x MEDs of UV irradiation, there were significant increases in sunburn cell formation, thymine dimer formation, matrix metalloproteinase-9 expression, and p53 protein expression. All these changes were attenuated by the antioxidant composition. UV irradiation also suppressed the amount of CD1a-expressing Langerhans cells, indicating immunosuppressive effects of a single 5x MED dose of UV irradiation. Pretreatment of skin with the antioxidant composition blocked this effect. This study confirms the protective role of a unique mixture of antioxidants containing vitamin C, ferulic acid, and phloretin on human skin from the harmful effects of UV irradiation. Phloretin, in addition to being a potent antioxidant, may stabilize and increase the skin availability of topically applied vitamin C and ferulic acid. We propose that antioxidant mixture will complement and synergize with sunscreens in providing photoprotection for human skin.

A Phase II Randomized Placebo-Controlled Trial of Oral N-acetylcysteine for Protection of Melanocytic Nevi against UV-Induced Oxidative Stress In Vivo.

PubMed

Cassidy, Pamela B; Liu, Tong; Florell, Scott R; Honeggar, Matthew; Leachman, Sancy A; Boucher, Kenneth M; Grossman, Douglas

2017-01-01

Oxidative stress plays a role in UV-induced melanoma, which may arise from melanocytic nevi. We investigated whether oral administration of the antioxidant N-acetylcysteine (NAC) could protect nevi from oxidative stress in vivo in the setting of acute UV exposure. The minimal erythemal dose (MED) was determined for 100 patients at increased risk for melanoma. Patients were randomized to receive a single dose (1,200 mg) of NAC or placebo, in double-blind fashion, and then one nevus was irradiated (1-2 MED) using a solar simulator. One day later, the MED was redetermined and the irradiated nevus and a control unirradiated nevus were removed for histologic analysis and examination of biomarkers of NAC metabolism and UV-induced oxidative stress. Increased expression of 8-oxoguanine, thioredoxin reductase-1, and γ-glutamylcysteine synthase modifier subunit were consistently seen in UV-treated compared with unirradiated nevi. However, no significant differences were observed in these UV-induced changes or in the pre- and postintervention MED between those patients receiving NAC versus placebo. Similarly, no significant differences were observed in UV-induced changes between subjects with germline wild-type versus loss-of-function mutations in the melanocortin-1 receptor. Nevi showed similar changes of UV-induced oxidative stress in an open-label post-trial study in 10 patients who received NAC 3 hours before nevus irradiation. Thus, a single oral dose of NAC did not effectively protect nevi from UV-induced oxidative stress under the conditions examined. Cancer Prev Res; 10(1); 36-44. ©2016 AACR. ©2016 American Association for Cancer Research.

Particle effects on ultraviolet disinfection of coliform bacteria in recycled water.

PubMed

Jolis, D; Lam, C; Pitt, P

2001-01-01

Pilot- and bench-scale coliform inactivation tests with UV irradiation were used to show how suspended solids remaining in filtered secondary effluent affect the efficiency of the UV disinfection process. Observed kinetic inactivation rates decreased with increasing suspended particle sizes of 7 microm or larger present in tertiary effluent. First-order inactivation rates estimated from collimated beam dose-response curves for discrete ranges of UV doses were substantially different, which should caution researchers not to compare inactivation data obtained with largely dissimilar UV doses or suspended particle distributions. A dose of approximately 800 J/m2 was identified as the minimum dose that will consistently meet the California wastewater reclamation coliform criterion when applied to in-line filtration effluent.

Disinfection of Mycobacterium avium subspecies hominissuis in drinking tap water using ultraviolet germicidal irradiation.

PubMed

Schiavano, Giuditta Fiorella; De Santi, Mauro; Sisti, Maurizio; Amagliani, Giulia; Brandi, Giorgio

2017-09-13

Nontuberculous mycobacteria are resistant to conventional water treatments, and are opportunistic human pathogen, particularly in hospitalized patients. The aim of this investigation was to assess the effectiveness of an ultraviolet UV-C lamp treatment against Mycobacterium avium subspecies hominissuis in drinking tap water. Ultraviolet treatments (0-192 mJ/cm 2 ) were performed using UV lamp immerged onto cylindrical glass tubes containing artificially contaminated water. The results showed that susceptibility to UV varied considerably according to the strains and the diameter of the tube. With a dose of 32 mJ/cm 2 , a significant inactivation (p < .05) of 3 log (99.9%) or more was obtained in only 5 of the 14 strains. To obtain a complete inactivation of all strains an irradiation of 192 mJ/cm 2 was needed, a dose that is much higher than the limits recommended by the international standards for UV disinfection of drinking water. In conclusion, it may be difficult to standardize a UV dose for the elimination of waterborne mycobacteria.

Integrated oxide graphene based device for laser inactivation of pathogenic microorganisms

NASA Astrophysics Data System (ADS)

Grishkanich, Alexsandr; Ruzankina, Julia; Afanasyev, Mikhail; Paklinov, Nikita; Hafizov, Nail

2018-02-01

We develop device for virus disinfection of pathogenic microorganisms. Viral decontamination can be carried out due to hard ultraviolet irradiation and singlet oxygen destroying the genetic material of a virus capsid. UV rays can destroy DNA, leading to the formation of dimers of nucleic acids. This practically does not occur in tissues, tk. UV rays penetrate badly through them, however, the viral particles are small and UV can destroy their genetic material, RNA / DNA and the virus can not replicate. It is with the construction of the ultraviolet laser water disinfection system (UFLOV) based on the continuous and periodic pulsed ultraviolet laser sources (pump) binds to solve sterility and depyrogenation of water. It has been established that small doses of UV irradiation stimulate reproduction, and large doses cause the death of pathogenic microorganisms. The effect of a dose of ultraviolet is the result of photochemical action on the substance of a living bacterial cell or virion. Also complex photodynamic laser inactivation on graphene oxide is realized.

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.

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.

Comparing three UV wavelengths for pre‐exposing Gafchromic EBT2 and EBT3 films

PubMed Central

Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Yabunaka, Kouichi

2015-01-01

Gafchromic films are used for X‐ray dose measurements during diagnostic examinations and have begun to be used for three‐dimensional X‐ray dose measurements using the high‐resolution characteristics of Gafchromic films for computed tomography. However, the problem of unevenness in Gafchromic film active layers needs to be resolved. Double exposures using X‐rays are performed during therapeutic radiology, although this is difficult for a diagnostic examination because of a heel effect. Thus, it has been suggested that ultraviolet (UV) radiation be used as a substitute for X‐rays. However, the appropriate UV wavelength has not been determined. Thus, we conducted this study to decide an appropriate UV wavelength. UV peak wavelengths of 245 nm (UV‐A), 310 nm (UV‐B), and 365 nm (UV‐C) were used to irradiate EBT2 and EBT3 films. Each UV wavelength was irradiated for 5, 15, 30, and 60 min, and irradiation was then repeated every 60 min up to 360 min. Gafchromic films were scanned after every irradiation using a flatbed scanner. Images were split into RGB images, and red images were analyzed using ImageJ, version 1.44, image analysis software. A region of interest (ROI) one‐half inch in diameter was placed in the center of subtracted Gafchromic film images, and UV irradiation times were plotted against mean pixel values. There were reactions in the front and back of Gafchromic EBT3 and the back of Gafchromic EBT2 with UV‐A and UV‐B. However, UV‐C resulted in some reactions in both sides of Gafchromic EBT2 and EBT3. The UV‐A and UV‐B wavelengths should be used. PACS number(s): 87.53 Bn PMID:26699578

UV Disinfection System for Cabin Air

NASA Astrophysics Data System (ADS)

Lim, Soojung

Ultraviolet (UV) radiation is commonly used for disinfection of water. As a result of advancements made in the last 10-15 years, the analysis and design of UV disinfection systems for water is well developed. UV disinfection is also used for disinfection of air; however, despite the fact the UV-air systems have a longer record of application than UV-water systems, the methods used to analyze and design UV-air disinfection systems remain quite empirical. It is well-established that the effectiveness of UV-air systems is strongly affected by the type of microorganisms, the irradiation level/type (lamp power and wavelength), duration of irradiation (exposure time), air movement pattern (mixing degree), and relative humidity. This paper will describe ongoing efforts to evaluate, design and test a UV-air system based on first principles. Specific issues to be addressed in this work will include laboratory measurements of relevant kinetics (i.e., UV dose-response behavior) and numerical simulations designed to represent fluid mechanics and the radiation intensity field. UV dose-response behavior of test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (e.g., bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to an environmental chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm2 accomplished 90% (1 log10 units) of the B. subtilis spore inactivation, whereas 99 % (2 log10 units) inactivation was accomplished at this same UV dose under 20% RH conditions. However, at higher doses, the result was opposite of that in low dose. Reactor behavior is simulated using an integrated application of computational fluid dynamics (CFD) and radiation intensity field models. These simulations followed a Lagrangian approach, wherein the UV radiation intensity field was mapped onto simulated particle trajectories for prediction of the UV dose delivered to each particle. By repeating these calculations for a large number of simulated particle trajectories, an estimate of the UV dose distribution delivered by the reactor can be made. In turn, these dose distribution estimates are integrated with the UV dose-response behavior described above to yield an estimate of microbial inactivation accomplished by the reactor. This modeling approach has the advantage of allowing simulation of many reactor configurations in a relatively short period of time. Moreover, by following this approach of "numerical prototyping," it is possible to "build" and analyze several virtual reactors before the construction of a physical prototype. As such, this procedure allows effective development of efficient reactors.

UV-Induced Triggering of a Biomechanical Initiation Switch Within Collagen Promotes Development of a Melanoma-Permissive Microenvironment in the Skin

DTIC Science & Technology

2012-09-01

addition, our new data suggest that pre-treating mice with anti-HU177 antibody inhibited UVB -induced accumulation of mast cells in the skin. Moreover, pre...work is provided below. Our previous studies have indicated that UVA and UVB irradiation can dose dependently trigger conformational changes in both...vitro following UV-irradiation was unlikely do to thermal denaturation. Interestingly, macrophage adhesion to UVB irradiated collagen type-IV but not

Garlic Supplementation Ameliorates UV-Induced Photoaging in Hairless Mice by Regulating Antioxidative Activity and MMPs Expression.

PubMed

Kim, Hye Kyung

2016-01-08

UV exposure is associated with oxidative stress and is the primary factor in skin photoaging. UV-induced reactive oxygen species (ROS) cause the up-regulation of metalloproteinase (MMPs) and the degradation of dermal collagen and elastic fibers. Garlic and its components have been reported to exert antioxidative effects. The present study investigated the protective effect of garlic on UV-induced photoaging and MMPs regulation in hairless mice. Garlic was supplemented in the diet, and Skh-1 hairless mice were exposed to UV irradiation five days/week for eight weeks. Mice were divided into four groups; Non-UV, UV-irradiated control, UV+1% garlic powder diet group, and UV+2% garlic powder diet group. Chronic UV irradiation induced rough wrinkling of the skin with hyperkeratosis, and administration of garlic diminished the coarse wrinkle formation. UV-induced dorsal skin and epidermal thickness were also ameliorated by garlic supplementation. ROS generation, skin and serum malondialdehyde levels were significantly increased by UV exposure and were ameliorated by garlic administration although the effects were not dose-dependent. Antioxidant enzymes such as superoxide dismutase and catalase activities in skin tissues were markedly reduced by UV irradiation and garlic treatment increased these enzyme activities. UV-induced MMP-1 and MMP-2 protein levels were suppressed by garlic administration. Furthermore, garlic supplementation prevented the UV-induced increase of MMP-1 mRNA expression and the UV-induced decrease of procollagen mRNA expression. These results suggest that garlic may be effective for preventing skin photoaging accelerated by UV irradiation through the antioxidative system and MMP regulation.

Different susceptibility of cells of porcine skin and internal organs to ultraviolet A-induced breaking of nuclear DNA.

PubMed

Brozyna, Anna; Chwirot, Barbara W

2005-01-01

There is a continuously growing interest in medical applications of ultraviolet radiation (UV-A and long-wavelength UV-B) especially for laser surgery, phototherapy and photodiagnostics of human internal organs. UV-B and UV-A radiation is potentially mutagenic, however, there has been very little information published to date concerning the significance of possible deleterious action of such photons on cells of internal tissues. The aim of this study is to compare the sensitivities of skin cells to those of internal organs upon exposure to UV-A. To assess this sensitivity we have determined the UV-A dose-dependent frequency of nuclear DNA breaks detected with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL) technique. The materials for the study were macroscopic samples of porcine skin, colon and esophagus. The UV-A dose ranged from 0.1 to 1000 mJ/cm2, which is similar to doses received by cells in regions examined with laser-induced fluorescence or by cells surrounding areas subject to a laser ablation. To reduce the influence of DNA repair processes the tissue samples were kept at a low temperature during the irradiation and were deep frozen immediately after completing the irradiation procedure. The cells of the internal organs are much more susceptible to UV-A-induced breaking of DNA than the skin cells. The percentage fractions and the spatial distributions of the damaged cells and the characteristics of the UV-A dose dependence seem to vary by type of internal organ.

Isolation of uv-sensitive variants of human FL cells by a viral suicide method

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

Shiomi, T.; Sato, K.

A new method (viral suicide method) for the isolation of uv-sensitive mutants is described. Colonies of mutagenized human FL cells were infected with uv-irradiated Herpes simplex viruses and surviving ones which seemed to be deficient in host cell reactivation (HCR) were examined for their uv sensitivity. Nineteen of 238 clones examined were sensitive to uv irradiation at the time of the isolation. After recloning, four of these clones have been studied and two (UVS-1 and UVS-2) of them are stable in their uv sensitivity for 4 months in culture. uv sensitivity of UVS-1, UVS-2, and the parental FL cells aremore » as follows: the extrapolation numbers (n) are 2.2, 2.1, and 1.8 and mean lethal doses (DO) are 2.9, 3.7, and 7.8 J/m/sup 2/ for UVS-1, UVS-2, and the parental FL cells, respectively. They are no more sensitive than FL cells to x-irradiation. The ability of HCR in UVS-2 cells is apparently lower than that in FL cells, whereas UVS-1 cells are the same as FL cells in the ability.« less

Ultraviolet exposure of Gafchromic XR‐RV3 and XR‐SP2 films

PubMed Central

Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Yabunaka, Kouichi

2015-01-01

Gafchromic film has been used for X‐ray dose measurement in diagnostic examinations. Their use has been initiated for three‐dimensional X‐ray dose measurement by using the high‐resolution characteristics of Gafchromic films in computed tomography. However, it is necessary to solve the problem of nonuniform thickness in the active layers of Gafchromic films. A double exposure technique using X‐rays is performed in therapeutic radiology; it is difficult to use in a diagnostic examination because of the heel effect. Therefore, it is suggested that ultraviolet (UV) rays be substituted for X‐rays. However, the appropriate UV wavelength is unknown. In this study, we aimed to determine which UV wavelengths are effective to expose Gafchromic XR‐RV3 and XR‐SP2. UV lamps with peak wavelengths of 245 nm, 310 nm, and 365 nm were used. The three UV wavelengths were used to irradiate Gafchromic XR‐RV3 and XR‐SP2 films for 60 min, and irradiation was repeated every 60 min for 600 min thereafter. Films were scanned after each irradiation period on a flatbed scanner. The images were split into their red‐green‐blue components, and red images were stored using ImageJ version 1.44o image analysis software. Regions of interest (ROI), 0.5 inches in diameter, were placed at the centers of the subtracted Gafchromic film images, and graphs of UV irradiation duration and mean pixel values were plotted. There were reactions to UV‐A on both Gafchromic XR‐RV3 and XR‐SP2; those to UV‐B were moderate. However, UV‐C demonstrated few reactions with Gafchromic XR‐RV3 and XR‐SP2. From these results, irradiation with UV‐A may be able to correct nonuniformity errors. Uniform UV‐A irradiation of Gafchromic films with large areas is possible, and UV rays can be used as a substitute for X‐rays in the double exposure technique. PACS number: 87.53 Bn PMID:26699326

The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

PubMed Central

Herkovits, J.; D’Eramo, J. L.; Fridman, O.

2006-01-01

The exposure of Bufo arenarum embryos to 300–310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. PMID:16823076

Radiation-induced change of optical property of hydroxypropyl cellulose hydrogel containing methacrylate compounds: As a basis for development of a new type of radiation dosimeter

NASA Astrophysics Data System (ADS)

Yamashita, Shinichi; Hiroki, Akihiro; Taguchi, Mitsumasa

2014-08-01

Hydrogels with matrix of a cellulose derivative, hydrogel of hydroxpropyl cellulose (HPC), containing two of methacrylate compounds (2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (9G)) were irradiated with 60Co γ-rays. The gels become white with irradiation, and thus, could be candidates of a new type of radiation dosimeter utilized in radiation therapy because the gels become white with irradiation and can be confirmed directly by human eyes even at low doses of 1-2 Gy. Radiation-induced change of optical properties, haze value and UV-vis absorption spectrum, of the irradiated gels was measured. Dose response of the white turbidity appearance was different for different compositions of the methacrylate compounds as well as for different dose rates. The degree of the radiation-induced white turbidity was quantified by measuring haze value, showing linear dose response in low dose region (<2 Gy). We also analyzed the gels with a UV-vis spectrometer and HEMA- and 9G-rich gels gave different spectral shapes, indicating that there are at least two mechanisms leading to the white turbidity. In addition, dose rate dependence was smaller for 9G-rich gels than HEMA-rich gels in the range of 0.015-1.5 Gy/min.

The fate of mitochondrial loci in rho minus mutants induced by ultraviolet irradiation of Saccharomyces cerevisiae: effects of different post-irradiation treatments.

PubMed

Heude, M; Moustacchi, E

1979-09-01

Three main features regarding the loss of mitochondrial genetic markers among rho- mutants induced by ultraviolet irradiation are reported: (a) the frequency of loss of six loci examined increases with UV dose; (b) preferential loss of one region of the mitochondrial genome observed in spontaneous rho- mutants is enhanced by UV; and (c) the loss of each marker results from large deletions. Marker loss in rho- mutants was also investigated under conditions that modulate rho- induction. Liquid holding of irradiated exponential or stationary phase cells, as well as a split-dose regime applied to stationary phase cells, results in rho- mutants in which the loss of markers is correlated with rho- induction: the more sensitive the cells are to rho- induction, the more frequent are the marker losses among rho- clones derived from these cells. This correlation is not found in exponential-phase cells submitted to a split-dose treatment, suggesting that a different mechanism is involved in the latter case. It is known that UV-induced pyrimidine dimers are not excised in a controlled manner in mitochondrial DNA. However, our studies indicate that an accurate repair mechanism (of the recombinational type ?) can lead to the restoration of mitochondrial genetic information in growing cells.

DNA Damage in Bone Marrow Cells Induced by Femtosecond and Nanosecond Ultraviolet Laser Pulses.

PubMed

Morkunas, Vaidotas; Gabryte, Egle; Vengris, Mikas; Danielius, Romualdas; Danieliene, Egle; Ruksenas, Osvaldas

2015-12-01

The purpose of this study was to investigate the possible genotoxic impact of new generation 205 nm femtosecond solid-state laser irradiation on the DNA of murine bone marrow cells in vitro, and to compare the DNA damage caused by both femtosecond and nanosecond UV laser pulses. Recent experiments of corneal stromal ablation in vitro and in vivo applying femtosecond UV pulses showed results comparable with or superior to those obtained using nanosecond UV lasers. However, the possible genotoxic effect of ultrashort laser pulses was not investigated. Mouse bone marrow cells were exposed to different doses of 205 nm femtosecond, 213 and 266 nm nanosecond lasers, and 254 nm UV lamp irradiation. The comet assay was used for the evaluation of DNA damage. All types of irradiation demonstrated intensity-dependent genotoxic impact. The DNA damage induced depended mainly upon wavelength rather than on other parameters such as pulse duration, repetition rate, or beam delivery to a target. Both 205 nm femtosecond and clinically applied 213 nm nanosecond lasers' pulses induced a comparable amount of DNA breakage in cells exposed to the same irradiation dose. To further evaluate the suitability of femtosecond UV laser sources for microsurgery, a separate investigation of the genotoxic and mutagenic effects on corneal cells in vitro and, particularly, in vivo is needed.

Changes in UV absorption of sunscreens after UV irradiation

NASA Astrophysics Data System (ADS)

Tarras-Wahlberg, N.; Stenhagen, G.; Larkö, O.; Rosén, A.; Wennberg, A.-M.; Wennerström, O.

2000-03-01

In the present investigation we have studied the change in the absorption spectrum of some photoactive organic species in sunscreens after UVA and UVB irradiation in a dose normally encountered during a full day in the sun. The absorbance of 2-ethylhexyl 4-methoxycinnamate was reduced significantly, while 3-(4-methylbenzyliden)camphor seemed to be rather stable. The benzophenones studied seemed to be relatively stable. In the case of 4-tert.butyl-4´-methoxy-dibenzoylmethane there was a rapid decrease in the UVA absorption leading to unsatisfactory protection in the UVA region. 4-Isopropyl-dibenzoylmethane also lost most of its UV protective capacity after irradiation with UVA. UVB seemed to have a minor effect on all the samples. The present study including gas chromatography and mass spectrometry analysis indicates that some of the photoactive organic species commonly used today in sunscreens are unstable following UV irradiation.

ACTION OF MUTAGENIC AGENTS ON AUXOTROPHIC STRAINS OF STREPTOMYCES

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

Jarai, M.

1962-01-01

The mutagenic effect on Streptomyces auxotrophs of uv and x irradiation and of some chemical agerts was studied. From the observed reverse mutations it was concluded that uv and probably x irradiation have an optimal mutagenic dose. With nine auxotrophic strains it was shown that under the same conditions different gene loci reacted differently to the same mutagenic agent. With uy radiation, mutations occurred most frequently at doses falling within the range of 3500 to 4000 erg/mm/sup 2/. With such doses, the average mutation frequency for singly deficient mutants was 0.8 x 10/sup -6/, for doubly deficient mutants 8.4 xmore » 10/sup -8/. An analysis of the number of mutations as compared to the number of survivors in two biochemical mutants (N-4 and N-11) showed that with N- 4 the highest number of mutations was obtained at doses of 3500 to 4500 erg/mm/ sup 2/, namely, 12 to 15 per 10 surviving conidia, and with strain N-11, the highest frequency was obtained in the same dose range, namely, three to four mutations per 10/sup 6/ surviving conidia. The optimal dose of irradiation corresponds to 90 to 97% lethality. It was shown that, unlike the results with uv irradiation, with x rays no such definite relation existed between optimal dose and frequency of mutations. The highest mutation frequency occurred at doses of 20,000 to 25,000 r, which corresponded to 85 to 91% lethality. Of the chemical substances examined, a definite mutagenic action was exerted by acridine orange, streptomycin, hydroxylamine, phenyl, isocyannte, and 8-quinolinol. The maximum mutagenic frequency for survivors was 41.4 x 10/sup -6/ after uv irradiation (biochemical mutant arg 3-; frequency of sportaneous back mutation, 0.041 x 10/sup -6/). With x irradiation the maximum mutagenic frequency was 3.42 x 10/sup -6/ (biochemical mutant meth 1-; frequency of spontaneous back mutation, 0.28 X 10/sup -6/). With chemical agents the maximum mutation frequencies for the initial conidia number were as follows: acridine orange, 3.65 x 10/sup -6/ (biochemical mutant arg 3-); streptomycin, 2.05 x 10/sup -6/ (biochemical mutant arg 3-); hydroxylamine, 5.81 x 10/sup -6/ (biochemical mutant meth 1/sup -/); phenyl isocyanate, 6.11 x 10/sup -6/ (biochemical mutant meth 1/sup -/); 8- quinolinol, 1.02 x 10/sup -6/ (biochemical mutant meth 1/sup -/). (BBB)« less

Pulsed UV laser light on Escherichia coli and Saccharomyces cerevisiae suspended in non-alcoholic beer

PubMed Central

Hosseini, SM; Azar-Daryany, MK; Massudi, R; Elikaei, A

2011-01-01

Background The aim of this study was to investigate the effect of pulsed ultra-violet (UV) irradiation on inactivation of beer spoilage microorganisms. UV irradiation is nowadays cost effective enough to compete with traditional biological, physical, and chemical treatment technologies and has become an alternative to such methods. Material and Methods Photoinactivation effects of pulsed UV laser with the wavelengths of 355 and 266 nm, which inactivate typical prokaryotic (Escherichia coli) and eukaryotic (Saccharomyces cerevisiae) microorganisms, were examined with different doses and exposure times. Results A dose of 100 J/cm2 of the 355 nm pulsed UV laser was able to reduce about 1 to 2 log (88.75%) of E.coli with the population of 1.6×108 colony-forming units (CFU/ml), and 97% of 3.2×107, 3×106, 5.5×105, and 9×104 CFU/ml. In the case of 266 nm, more than 99% reduction in E. coli serial dilutions was inactivated, using 10 J/cm2 with exception of 7×104 CFU/ml which was not detected any bacterial growth using 5 J/cm2. In addition, 50, 40, and 20 J/cm2 energy were used successfully to inactivate S. cerevisiae at the populations of 5.4×106, 7×105, 5×104 and 4×103 CFU/ml, respectively. As a result, pulsed UV Laser with 266 nm was strong enough to inactivate a high titer of bacterial and yeast indicator standards suspended in non-alcoholic beer in comparison with 355nm doses. Conclusion Results indicate that pulsed UV technology, in principle, is an attractive alternative to conventional methods for the inactivation of indicator microorganisms and has potential in irradiation of unpasteurized beer. PMID:22347580

Rapid transcriptome responses of maize (Zea mays) to UV-B in irradiated and shielded tissues

PubMed Central

Casati, Paula; Walbot, Virginia

2004-01-01

Background Depletion of stratospheric ozone has raised terrestrial levels of ultraviolet-B radiation (UV-B), an environmental change linked to an increased risk of skin cancer and with potentially deleterious consequences for plants. To better understand the processes of UV-B acclimation that result in altered plant morphology and physiology, we investigated gene expression in different organs of maize at several UV-B fluence rates and exposure times. Results Microarray hybridization was used to assess UV-B responses in directly exposed maize organs and organs shielded by a plastic that absorbs UV-B. After 8 hours of high UV-B, the abundance of 347 transcripts was altered: 285 were increased significantly in at least one organ and 80 were downregulated. More transcript changes occurred in directly exposed than in shielded organs, and the levels of more transcripts were changed in adult compared to seedling tissues. The time course of transcript abundance changes indicated that the response kinetics to UV-B is very rapid, as some transcript levels were altered within 1 hour of exposure. Conclusions Most of the UV-B regulated genes are organ-specific. Because shielded tissues, including roots, immature ears, and leaves, displayed altered transcriptome profiles after exposure of the plant to UV-B, some signal(s) must be transmitted from irradiated to shielded tissues. These results indicate that there are integrated responses to UV-B radiation above normal levels. As the same total UV-B irradiation dose applied at three intensities elicited different transcript profiles, the transcriptome changes exhibit threshold effects rather than a reciprocal dose-effect response. Transcriptome profiling highlights possible signaling pathways and molecules for future research. PMID:15003119

Wastewater disinfection alternatives: chlorine, ozone, peracetic acid, and UV light.

PubMed

Mezzanotte, V; Antonelli, M; Citterio, S; Nurizzo, C

2007-11-01

Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (C x t) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time.

Truffles decontamination treatment by ionizing radiation

NASA Astrophysics Data System (ADS)

Adamo, M.; Capitani, D.; Mannina, L.; Cristinzio, M.; Ragni, P.; Tata, A.; Coppola, R.

2004-09-01

A research project, funded by the Italian Ministry of Research and the European Union, is in progress aimed to develop processes to enhance, by irradiation, the safety and the wholesomeness of fresh products relevant for Italian food industry. Irradiation was performed on truffles, since the bacterial contamination impairs their trade in foreign countries. The microbial population and the shelf life under refrigeration were studied either on samples untreated or on samples submitted to γ-rays in a 1-2.5 kGy dose range. The effect of the treatment was monitored by UV and NMR techniques. Total microbial population and the shelf life prolongation were investigated. The synergistic effect of the dose, the packaging under vacuum and the storage/irradiation temperature resulted in a direct effect on the microbial load, spoilage and shelf life. After the irradiation, small variations in the intensity of some NMR resonances due to aromatic compounds and other unassigned compounds were observed. As confirmed by UV spectrophotometric data, these phenomena seemed to originate from a small degradation of polyphenols; the induced growth of soluble phenols suggested that the 1.5 kGy dose can be considered as the radiation dose threshold beyond which clear chemical modifications on truffles appear.

Global Mapping of Underwater UV Irradiances and DNA-Weighted Exposures using TOMS and SeaWiFS Data Products

NASA Technical Reports Server (NTRS)

Vasilkov, Alexander; Krotkov, Nickolay; Herman, Jay; McClain, Charles; Arrigo, Kevin; Robinson, Wayne

1999-01-01

The global stratospheric ozone-layer depletion results In an increase in biologically harmful ultraviolet (UV) radiation reaching the surface and penetrating to ecologically significant depths in natural waters. Such an increase can be estimated on a global scale by combining satellite estimates of UV irradiance at the ocean surface from the Total Ozone Mapping Spectrometer (TOMS) satellite instrument with the SeaWIFS satellite ocean-color measurements in the visible spectral region. In this paper we propose a model of seawater optical properties in the UV spectral region based on the Case I water model in the visible range. The inputs to the model are standard monthly SeaWiFS products: chlorophyll concentration and the diffuse attenuation coefficient at 490nm. Penetration of solar UV radiation to different depths in open ocean waters is calculated using the RT (radiative transfer) quasi-single scattering approximation (QSSA). The accuracy of the QSSA approximation in the water is tested using more accurate codes. The sensitivity study of the underwater UV irradiance to atmospheric and oceanic optical properties have shown that the main environmental parameters controlling the absolute levels of the UVB (280-320nm) and DNA-weighted irradiance underwater are: solar-zenith angle, cloud transmittance, water optical properties, and total ozone. Weekly maps of underwater UV irradiance and DNA-weighted exposure are calculated using monthly-mean SeaWiFS chlorophyll and diffuse attenuation coefficient products, daily SeaWiFS cloud fraction data, and the TOMS-derived surface UV irradiance daily maps. The final products include global maps of weekly-average UVB irradiance and DNA-weighted daily exposures at 3m and 10m, and depths where the UVB irradiance and DNA-weighted dose rate at local noon are equal to 10% of their surface values.

UV-B exposure impairs resistance to infection by Trichinella spiralis

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

Goettsch, W.; Garssen, J.; Deijns, A.

1994-03-01

To assess the possibility that increases in UV-B exposure on the earth's surface could lead to impaired resistance to several infectious diseases, we studied the effect of UV-B exposure on resistance against Trichinella spiralis. Wistar rats, orally infected with T. spiralis larvae, were exposed to suberythemal doses of UV-B radiation daily for 5 days at different time periods before or after infection. A significant increase in the number of Trichinella larvae was found in the carcasses of rats irradiated with UV-B between 6 and 10 days after infection. These data indicate that exposure to UV-B radiation suppresses the resistance tomore » a parasitic infection. We suggested that UV-B radiation especially suppresses cellular immune responses against these worms because specific IgM, IgG, and IgE titers were not significantly altered by UV-B exposure. These data indicate that UV-B irradiation plays a role in the course of infection with T. spiralis, which suggests that increases of UV-B exposure might also lead to problems with other infectious diseases and might affect vaccination because of the interaction of UV-B irradiation with memory T-cells. 38 refs., 3 figs., 1 tab.« less

Comparison of the effect of plasma treatment and gamma ray irradiation on PS-Cu nanocomposite films surface

NASA Astrophysics Data System (ADS)

Farag, O. F.

2018-06-01

Polystyrene-copper (PS-Cu) nanocomposite films were treated with DC N2 plasma and gamma rays irradiations. The plasma treatment of PS-Cu film surface was carried out at different treatment times, gas pressure 0.4 Torr and the applied power 3.5 W. On the other hand, the treatment with gamma rays irradiation were carried out at irradiation doses 10, 30 and 50 kGy. The induced changes in surface properties of PS-Cu films were investigated with UV-viss spectroscopy, scanning electron microscopy (SEM) and FTIR spectroscopy techniques. In addition, the wettability property, surface free energy, spreading coefficient and surface roughness of the treated samples were studied by measuring the contact angle. The UV-viss spectroscopy analysis revealed that the optical band gap decreases with increasing the treatment time and the irradiation dose for plasma and gamma treatments, respectively. SEM observations showed that the particle size of copper particles was increased with increasing the treatment time and the irradiation dose, but gamma treatment changes the copper particles size from nano scale to micro scale. The contact angle measurements showing that the wettability property, surface free energy, spreading coefficient and surface roughness of the treated PS-Cu samples were increased remarkably with increasing the treatment time and the irradiation dose for plasma and gamma treatments, respectively. The contact angle, surface free energy, spreading coefficient and surface roughness of the treated PS-Cu samples are more influenced by plasma treatment than gamma treatment.

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

NASA Astrophysics Data System (ADS)

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

2017-06-01

This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS UV doses were found to be ˜ 12.5 % higher than the NILU NN estimates but, despite the presence of a visually apparent seasonal pattern, the R2 values were found to be robustly high and equal to 0.92-0.93 for 1588 all-sky coincidences. These results significantly improve when limiting the dataset to cloud-free days with differences of 0.57 % for the erythemal doses, 1.22 % for the vitamin D doses, and 1.18 % for the DNA-damage doses, with standard deviations of the order of 11-13 %. The improvement of the comparative statistics under cloud-free cases further testifies to the importance of the appropriate consideration of the contribution of clouds in the UV radiation reaching the Earth's surface. For the urban area of Thessaloniki, with highly variable aerosol, the weakness of the implicit aerosol information introduced to the TEMIS UV dose algorithm was revealed by comparison of the datasets to aerosol optical depths at 340 nm as reported by a collocated CIMEL sun photometer, operating in Thessaloniki at LAP/AUTh as part of the NASA Aerosol Robotic Network.

Dark Period Following UV-C Treatment Enhances Killing of Botrytis cinerea Conidia and Controls Gray Mold of Strawberries.

PubMed

Janisiewicz, Wojciech J; Takeda, Fumiomi; Glenn, D Michael; Camp, Mary J; Jurick, Wayne M

2016-04-01

Strawberries are available throughout the year either from production in the field or from high and low tunnel culture. Diversity of production conditions results in new challenges in controlling diseases before and after harvest. Fungicides have traditionally been used to control these diseases; however, their limitations necessitate a search for new approaches. We found that UV-C irradiation of Botrytis cinerea, a major pathogen of strawberry, can effectively kill this fungus if a dark period follows the treatment. The inclusion of a 4-h dark period resulted in almost complete kill of B. cinerea conidia on agar media at a dose of 12.36 J/m2. The UV-C dose did not cause a reduction in photosynthesis in strawberry leaves or discoloration of sepals, even after exposing plants repeatedly (twice a week) for 7 weeks. Although irradiation of dry conidia of B. cinerea with this dose resulted in some survival, the conidia were not infective and not able to cause decay even when inoculated onto a highly susceptible mature apple fruit. Irradiation of strawberry pollen at 12.36 J/m2 did not affect pollen germination, tube growth and length in vitro, or germination and tube growth in the style of hand-pollinated emasculated strawberry flowers. No negative effect of the UV-C treatment was observed on fruit yield and quality in high tunnel culture. In the fruit and flower petal inoculation tests, the UV-C treatment was highly effective in reducing fruit decay and petal infection. This UV-C treatment with an exposure time of 60 s may be useful in controlling gray mold in tunnel production of strawberries and may also have the potential for use in intensive field and indoor production of other fruits and vegetables providing that a 4-h dark period follows the irradiation.

Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

NASA Astrophysics Data System (ADS)

Ali, Dilawar; Butt, M. Z.; Ishtiaq, Mohsin; Waqas Khaliq, M.; Bashir, Farooq

2016-11-01

Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm-2. Optical, structural, and chemical properties were investigated by UV-vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm-1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of -CH2- group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm-2.

Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

NASA Astrophysics Data System (ADS)

Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

2017-11-01

The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.

Treating cell culture media with UV irradiation against adventitious agents: minimal impact on CHO performance.

PubMed

Yen, Sandi; Sokolenko, Stanislav; Manocha, Bhavik; Blondeel, Eric J M; Aucoin, Marc G; Patras, Ankit; Daynouri-Pancino, Farnaz; Sasges, Michael

2014-01-01

Sterility of cell culture media is an important concern in biotherapeutic processing. In large scale biotherapeutic production, a unit contamination of cell culture media can have costly effects. Ultraviolet (UV) irradiation is a sterilization method effective against bacteria and viruses while being non-thermal and non-adulterating in its mechanism of action. This makes UV irradiation attractive for use in sterilization of cell culture media. The objective of this study was to evaluate the effect of UV irradiation of cell culture media in terms of chemical composition and the ability to grow cell cultures in the treated media. The results showed that UV irradiation of commercial cell culture media at relevant disinfection doses impacted the chemical composition of the media with respect to several carboxylic acids, and to a minimal extent, amino acids. The cumulative effect of these changes, however, did not negatively influence the ability to culture Chinese Hamster Ovary cells, as evaluated by cell viability, growth rate, and protein titer measurements in simple batch growth compared with the same cells cultured in control media exposed to visible light. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers.

Inactivation of the Hutchinson strain of non-A, non-B hepatitis virus by combined use of beta-propiolactone and ultraviolet irradiation

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

Prince, A.M.; Stephan, W.; Dichtelmueller, H.B.

1985-06-01

A beta-propiolactone/ultraviolet irradiation procedure (beta PL/UV) has been evaluated for its ability to inactivate 30,000 chimpanzee infectious doses of the Hutchinson strain of non-A, non-B (NANB) virus. The chimpanzees were inoculated with plasma to which this dose of the titrated virus had been added prior to application of the beta PL/UV process in accordance with a procedure used for licensed blood derivatives in Germany. Neither animal developed hepatitis. When subsequently challenged with the same contaminated plasma, which had not been sterilized, both animals promptly developed typical NANB hepatitis. This study extends the high (approximately 10(7)-fold) process efficiency of the betamore » PL/UV procedure previously reported for hepatitis B virus to a blood-borne NANB virus.« less

Effect of smokeless tobacco and tobacco-related chemical carcinogens on survival of ultraviolet light-inactivated herpes simplex virus

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

Dokko, H.; Min, P.S.; Cherrick, H.M.

1991-04-01

Low doses of ultraviolet (UV) light, x-rays, photodynamic treatment, or aflatoxins increase the survival of UV-irradiated virus in cells. This effect is postulated to occur by enhancement of the error-prone cellular repair function, which could also be associated with oncogenic cell transformation. The present study was designed to investigate whether treatment of green monkey kidney cells with water extract of snuff (snuff extract), benzo(a)pyrene, nicotine, or tobacco-specific N'-nitrosamines would result in enhanced survival of UV-irradiated herpes simplex virus (HSV). Exposure of the cells with snuff extract, benzo(a)pyrene, N'-nitrosonornicotine, or 4-(N-methyl-N'-nitrosamino)-1-(3-pyridyl)-1-butanone resulted in an enhancement of survival of UV-irradiated HSV typemore » 1 compared with the control whereas exposure of the cells with nicotine did not. These data indicate that the water-extractable component of snuff and tobacco-related chemical carcinogens increase the cellular repair mechanism and provides for increased survival of UV-irradiated HSV.« less

Adipose-derived mesenchymal stem cells reduce MMP-1 expression in UV-irradiated human dermal fibroblasts: therapeutic potential in skin wrinkling.

PubMed

Son, Woo-Chan; Yun, Jun-Won; Kim, Bae-Hwan

2015-01-01

Adipose-derived mesenchymal stem cells (AdMSCs) have been reported to have therapeutic benefit in skin. The aim of this study was to examine the effects of AdMSCs in UV-irradiated human dermal fibroblasts (HDFs) for therapeutic potential in skin wrinkling. UV irradiation, a model naturally mimic skin wrinkle formation, is known to increase matrix metalloproteinase-1 (MMP-1), making MMP-1 a target for skin photoaging. Our findings identified that AdMSCs reduce MMP-1 level in UV-irradiated HDFs and increase type 1 procollagen in HDFs. A dose-dependent increase in type 1 procollagen was confirmed by AdMSC-conditioned medium. Importantly, our current findings showing the effects of AdMSCs on the induction of MMP-1 in UV-radiated HDFs and the expression of collagen in HDFs can provide an evidence of relationship between MMP-1 and procollagen production for the protection against wrinkle formation. Collectively, AdMSCs may contribute to anti-wrinkle effects in skin but further experiments are needed to identify the mechanism.

Protective effect of poly (α- L-glutamate) against UV and γ-irradiation

NASA Astrophysics Data System (ADS)

Furuta, Masakazu; Huy, Nguyen Quang; Tsuchiya, Akihito; Nakatsuka, Hiroshige; Hayashi, Toshio

2004-09-01

We occasionally found that poly (α- L-glutamate) showed a superior protective effect on enzymes against UV and 60Co-γ irradiation. We selected papain and α-amylase as a model enzyme and irradiated the aqueous solution (10 mg/ml) of each enzyme with UV and 60Co-γ rays in the presence of poly (α- L-glutamate) (α-PGA), poly (glucosyl oxyethyl methacrylate (GEMA)), and glucose (1.25% w/v each). The mixture of the three compounds has a significant protective effect on the activity of papain solution showing 40% of remaining activity twice as much as the control containing no additive at the dose of 15 kGy. Among them, α-PGA showed the highest protecting effect on the both papain and α-amylase even after 10-kGy irradiation at which 50% of the activity was retained. α-PGA also showed significant protective activity on α-amylase against UV both in solution and under dried state.

[Photodamage and photoaging--prevention and treatment].

PubMed

Grether-Beck, Susanne; Wlaschek, Meinhard; Krutmann, Jean; Scharffetter-Kochanek, Karin

2005-09-01

The exposure of human skin to environmental and artificial ultraviolet irradiation has increased significantly. This is not only due to an increased solar UV irradiation as a consequence of the stratospheric ozone depletion, but also the result of an inappropriate social behaviour with the use of tanning parlors being very popular. Besides this, leisure activities and living style with travelling to equatorial regions also add to the individual annual UV load. Since the population in industrialised countries shows an increasing total life span, in parallel the cumulative life time dose of solar and artificial UV-irradiation is dramatically augmented. In addition to the common longterm detrimental effects like immunosuppression and skin cancer, the photooxidative damage due to energy absorption of UV photons in an oxygenized environment leads to alterations of cells, subcellular compartments and macromolecules. The clinical manifestations of UV/ROS induced disturbances result in photoaged skin with wrinkle formation, laxity, leathery appearance as well as fragility, impaired wound healing and higher vulnerability. Strategies to prevent or to minimize photoaging and intrinsic aging of the skin necessarily include protection against UV irradiation and antioxidant homoeostasis. New developments of therapeutic interventions including DNA repair enzymes will be discussed.

Comparative study of nuclear magnetic resonance and UV-visible spectroscopy dose-response of polymer gel based on N-(Isobutoxymethyl) acrylamide

NASA Astrophysics Data System (ADS)

Lotfy, S.; Basfar, A. A.; Moftah, B.; Al-Moussa, A. A.

2017-12-01

A comparative study of nuclear magnetic resonance and UV-visible spectroscopy of dose-response for polymer gel dosimeters was performed. Dosimeters were prepared using N-(Isobutoxymethyl) acrylamide (NIBMA) as a new monomer via radiation induced polymerization for use in radiotherapy planning. The prepared dosimeters were irradiated with doses up to 30 Gy at a constant dose rate of 600 MU/min. Using a medical linear accelerator at irradiation energies of 6, 10 and 18 MV photon beam. The nuclear magnetic resonance (NMR), via spin-spin relaxation rate (R2) for water proton surrounding the polymer formulation and UV-Visible spectroscopy, via the optical absorbance measurements of irradiated dosimeters at selected wavelengths of 500 nm, was used to investigate the dose response of NIBMAGAT gel dosimeters. Scavenge of oxygen was done using tetrakis (hydroxymethyl) phosphonium chloride (THPC). The THPC optimum concentration in the dosimeters formulations were 5 and 10 mM for the NMR and optical absorbance measurements respectively. The quantitative investigation of the dosimeters components reveals the selective formulations based on 4% w/w gelatin, 1% w/w NIBMA, 3% w/w BisAAm, 5 or 10 mM THPC and 17% w/w glycerol which significantly increase the dosimeters dose response. The prepared dosimeters were found to be dose rate and photon beam irradiation energy independent. The stability study shows no change in the relaxation rate or in the optical absorbance of the gel dosimeters up to 8 days post-irradiation. The prepared polymer gel dosimeters at the energies of 6, 10 and 18 MV photon beam irradiation in the range of 1-30 Gy have the linearity of the dose response function in the case of R2 is better than in the case of absorbance measurements; correlation coefficient (r2) equals 0.995 and 0.991, respectively. Dose sensitivity, R2 of NIBMAGAT dosimeters (0.0775 s-1 Gy-1). The absorption band intensity increases linearly with a dose sensitivity of 0.016 cm-1 Gy-1. The detection limit of the present dosimeter analyzed by R2 and absorbance measurements is 1 Gy and 2 Gy respectively. The overall uncertainty measurements of dose approve that by using the absorbance measurements the gel is not useful as a dosimeter like as R2 measurements. It could be a new composition of dosimeters successfully utilized for MRI (Magnetic Resonance Imaging) for radiotherapy treatment planning.

Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

NASA Astrophysics Data System (ADS)

Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

2016-04-01

Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

UV-induced transformation of four halobenzoquinones in drinking water.

PubMed

Qian, Yichao; Wang, Wei; Boyd, Jessica M; Wu, Minghuo; Hrudey, Steve E; Li, Xing-Fang

2013-05-07

Halobenzoquinones (HBQs) are a group of emerging disinfection byproducts (DBPs) found in treated drinking water. Because the use of UV treatment for disinfection is becoming more widespread, it is important to understand how the HBQs may be removed or changed due to UV irradiation. Water samples containing four HBQs, 2,6-dichloro-1,4-benzoquinone (DCBQ), 2,3,6-trichloro-1,4-benzoquinone (TCBQ), 2,6-dichloro-3-methyl-1,4-benzoquinone (DCMBQ), and 2,6-dichloro-1,4-benzoquinone (DBBQ), were treated using a modified bench scale collimated beam device, mimicking UV treatment. Water samples before and after UV irradiation were analyzed for the parent compounds and products using a high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method. As much as 90% of HBQs (0.25 nmol L(-1)) in both pure water and tap water were transformed to other products after UV254 irradiation at 1000 mJ cm(-2). The major products of the four HBQs were identified as 3-hydroxyl-2,6-dichloro-1,4-benzoquinone (OH-DCBQ) from DCBQ, 5-hydroxyl-2,6-dichloro-3-methyl-1,4-benzoquinone (OH-DCMBQ) from DCMBQ, 5-hydroxyl-2,3,6-trichloro-1,4-benzoquinone (OH-TCBQ) from TCBQ, and 3-hydroxyl-2,6-dibromo-1,4-benzoquinone (OH-DBBQ) from DBBQ. These four OH-HBQs were further modified to monohalogenated benzoquinones when the UV dose was higher than 200 mJ cm(-2). These results suggested possible pathways of UV-induced transformation of HBQs to other compounds. Under the UV dose commonly used in water treatment plants, it is likely that HBQs are partially converted to other halo-DBPs. The occurrence and toxicity of these mixed DBPs warrant further investigation to understand whether they pose a health risk.

Optimisation of UV irradiation as a binding site conserving method for crosslinking collagen-based scaffolds.

PubMed

Davidenko, Natalia; Bax, Daniel V; Schuster, Carlos F; Farndale, Richard W; Hamaia, Samir W; Best, Serena M; Cameron, Ruth E

2016-01-01

Short wavelength (λ = 254 nm) UV irradiation was evaluated over a range of intensities (0.06 to 0.96 J/cm(2)) as a means of cross-linking collagen- and gelatin-based scaffolds, to tailor their material characteristics whilst retaining biological functionality. Zero-link carbodiimide treatments are commonly applied to collagen-based materials, forming cross-links from carboxylate anions (for example the acidic E of GFOGER) that are an essential part of integrin binding sites on collagen. Cross-linking these amino acids therefore disrupts the bioactivity of collagen. In contrast, UV irradiation forms bonds from less important aromatic tyrosine and phenylalanine residues. We therefore hypothesised that UV cross-linking would not compromise collagen cell reactivity. Here, highly porous (~99 %) isotropic, collagen-based scaffolds were produced via ice-templating. A series of scaffolds (pore diameters ranging from 130-260 μm) with ascending stability in water was made from gelatin, two different sources of collagen I, or blends of these materials. Glucose, known to aid UV crosslinking of collagen, was added to some lower-stability formulations. These scaffolds were exposed to different doses of UV irradiation, and the scaffold morphology, dissolution stability in water, resistance to compression and cell reactivity was assessed. Stabilisation in aqueous media varied with both the nature of the collagen-based material employed and the UV intensity. Scaffolds made from the most stable materials showed the greatest stability after irradiation, although the levels of cross-linking in all cases were relatively low. Scaffolds made from pure collagen from the two different sources showed different optimum levels of irradiation, suggesting altered balance between stabilisation from cross-linking and destabilisation from denaturation. The introduction of glucose into the scaffold enhanced the efficacy of UV cross-linking. Finally, as hypothesized, cell attachment, spreading and proliferation on collagen materials were unaffected by UV cross-linking. UV irradiation may therefore be used to provide relatively low level cross-linking of collagen without loss of biological functionality.

Effect of amino acid starvation on UV sensitivity of Lactobacillus acidophilus cells

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

Soška, J.; Nečasová, J.

1973-11-01

In Lactobacillus acidophilus cultures uv irradiated in the exponential phase of growth, the dose-survival curve was of the simple exponential type, without any shoulder. If the bacteria were subjected to amino acid starvation prior to irradiation, a shoulder corresponding to a quasi-threshold dose (D) of about 780 ergs/mm/sup 2/ appeared in the curve. The administration of protein- or RNA-synthesis inhibitors prior to irradiation had the same effect. The effect of pre-irradiation amino acid starvation was abolished by simuitaneous thymidine starvation. It was likewise abolished if amino acid starvation was followed by incubation in the presence of amino acids (without thymidine)more » and then by irradiation of the cells. Post-irradiation amino acid starvation did not lead to the formation of a shoulder but if combined with thymidine starvation it did. It can be concluded from the results that post-irradiation repair processes are facilitated or promoted if, during the post-irradiation interval DNA synthesis is delayed. This delay represents a compensation of the pre-irradiation increase of cellular DNA-content, taking place during inhibition of proteosynthesis. The post-irradiation administration of caffeine did not abolish the formation of the shoulder induced by pre-irradiation amino acid starvation; on the contrary, it induced its formation even in exponentially growing, irradiated control bacteria. (auth)« less

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

NASA Astrophysics Data System (ADS)

Terenetskaya, Irina; Orlova, Tatiana

2005-09-01

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

Dark recovery of uv-irradiated phage TI. I. A minor recovery effect whose exclusion permits the study of survival kinetics under presumably repairless conditions

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

Harm, W.

1973-12-01

The survival of uv-irradiated phage Tl is much lower in excision repair- deficient than in excision repair-proficient E.coli cells, due to lack of host ceH reactivation (HCR). sn additional decrease in phage survival occurs when repair-deficient (HCR-) host cells have been exposed to uv doses from 3000 to 10,000 erg mm/-sup 2/ of 254 nm uv radiation prior to infection. The observed effect is attributed to loss of a minor phage recovery process, which requires neither the bacterial excision repair nor the bacterial REC repair system. This type of recovery is little affected by caffeine or acriflavine at concentrations thatmore » preclude HCR completely. Its full inhibition by uv-irradiation of the cells requires on approximately 8 times larger dose than complete inhibition of HCR. In heavily preirradiated cells, the TI burst size is extremely small and multiplicity reactivation is considerably less extensive than in unirradiated cells. Presumably the survival of singly infecting Tl in these cells reflects absence of any type of repair. The observed phage sensitivity and shape of the curve are compatible with the expectation for completely repairless conditions. The mechanism underlying the minor recovery is not known; theoretical considerations make a phage REC repair mechanism seem likely. (auth)« less

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.

Evaluation of optically transparent polyetherimide films for applications in space

NASA Technical Reports Server (NTRS)

St. Clair, Anne K.; Slemp, Wayne S.

1991-01-01

Several series of aromatic polyetherimide films have been synthesized and characterized with the objective of obtaining maximum optical transparency for applications in space. Incorporation of phenoxy groups into aromatic polyimides has resulted in a reduction in the color intensity of these films compared to commercial polyimide film by reducing electronic interactions between polymer chains. The resulting lightly colored to colorless polyetherimide films have been characterized by UV-visible and infrared spectroscopy before and after exposure to varying doses of UV and electron irradiation designed to simulate use as second-surface mirror thermal control coatings. After exposure to 300 equivalent solar hours UV irradiation and 1 MeV electron irradiation, the polyetherimides were 2.2 to 2.6 times more transparent than commercial polyimide film of the same thickness.

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

NASA Astrophysics Data System (ADS)

Mendeva, B. D.; Gogosheva, Ts. N.; Petkov, B. H.; Krastev, D. G.

The results from direct ground-based solar UV irradiance measurements and the total ozone content (TOC) over Stara Zagora (42° 25'N, 25° 37'E), Bulgaria are presented. During the period 1999-2003 the TOC data show seasonal variations, typical for the middle latitudes - maximum in the spring and minimum in the autumn. The comparison between TOC ground-based data and Global Ozone Monitoring Experiment (GOME) satellite-borne ones shows a seasonal dependence of the differences between them. A strong negative relationship between the total ozone and the 305 nm wavelength irradiance was found. The dependence between the two variables is significant ( r = -0.62 ± 0.18) at 98% confidence level. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained. The estimation of the radiation amplification factor RAF shows that the ozone reduction by 1% increases the erythemal dose by 2.3%. The eye-damaging doses are more influenced by the TOC changes and in this case RAF = -2.7%. The amount of these biological doses depended on the solar altitude over the horizon. This dependence was not so strong when the total ozone content in the atmosphere was lower.

Metal adsorption of gamma-irradiated carboxymethyl cellulose/polyethylene oxide blend films

NASA Astrophysics Data System (ADS)

El-Naggar, Amal A.; Magida, M. M.; Ibrahim, Sayeda M.

2016-03-01

Blend films of different ratios of carboxymethyl cellulose (CMC)/polyethylene oxide (PEO) were prepared by the solution casting method. To investigate the effect of irradiation on all properties of prepared blend, it was exposed to different gamma irradiation doses (10, 20, and 30 kGy). Physical properties such as gel fraction (GF) (%) and swelling (SW) (%) were investigated. It was found that the GF (%) increases with increasing irradiation dose up to 20 kGy, while SW (%) decreases with an increase in the irradiation doses for all blend compositions. Moreover, the structural and mechanical properties of the prepared films were studied. The results of the mechanical properties obtained showed that there is an improvement in these properties with an increase in both CMC and irradiation dose up to 20 kGy. The efficiency of metal ions uptake was measured using a UV spectrophotometer. The prepared films showed good tendency to absorb and release metal ions from aqueous media. Thus, the CMC/PEO film can be used in agricultural domain.

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.

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

PubMed

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

2011-11-01

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

Radiation damage of all-silica fibers in the UV region

NASA Astrophysics Data System (ADS)

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

1999-04-01

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

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.

Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

PubMed

Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

2017-12-01

Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Inactivation of Cytomegalovirus in Breast Milk Using Ultraviolet-C Irradiation: Opportunities for a New Treatment Option in Breast Milk Banking

PubMed Central

Hod, Nurul; Jayaraman, Jothsna; Marchant, Elizabeth A.; Christen, Lukas; Chiang, Peter; Hartmann, Peter; Simmer, Karen

2016-01-01

Pasteurized donor human milk is provided by milk banks to very preterm babies where their maternal supply is insufficient or unavailable. Donor milk is currently processed by Holder pasteurization, producing a microbiologically safe product but significantly reducing immunoprotective components. Ultraviolet-C (UV-C) irradiation at 254 nm is being investigated as an alternative treatment method and has been shown to preserve components such as lactoferrin, lysozyme and secretory IgA considerably better than Holder pasteurization. We describe the inactivation of cytomegalovirus, a virus commonly excreted into breast milk, using UV-C irradiation. Full replication was ablated by various treatment doses. However, evidence of viral immediate early proteins within the cells was never completely eliminated indicating that some viral gene transcription was still occurring. In conclusion, UV-C may be a safe alternative to pasteurisation for the treatment of human donor milk that preserves the bioactivity. However, our data suggests that CMV inactivation will have to be carefully evaluated for each device designed to treat breast milk using UV-C irradiation. PMID:27537346

Inactivation of Cytomegalovirus in Breast Milk Using Ultraviolet-C Irradiation: Opportunities for a New Treatment Option in Breast Milk Banking.

PubMed

Lloyd, Megan L; Hod, Nurul; Jayaraman, Jothsna; Marchant, Elizabeth A; Christen, Lukas; Chiang, Peter; Hartmann, Peter; Shellam, Geoffrey R; Simmer, Karen

2016-01-01

Pasteurized donor human milk is provided by milk banks to very preterm babies where their maternal supply is insufficient or unavailable. Donor milk is currently processed by Holder pasteurization, producing a microbiologically safe product but significantly reducing immunoprotective components. Ultraviolet-C (UV-C) irradiation at 254 nm is being investigated as an alternative treatment method and has been shown to preserve components such as lactoferrin, lysozyme and secretory IgA considerably better than Holder pasteurization. We describe the inactivation of cytomegalovirus, a virus commonly excreted into breast milk, using UV-C irradiation. Full replication was ablated by various treatment doses. However, evidence of viral immediate early proteins within the cells was never completely eliminated indicating that some viral gene transcription was still occurring. In conclusion, UV-C may be a safe alternative to pasteurisation for the treatment of human donor milk that preserves the bioactivity. However, our data suggests that CMV inactivation will have to be carefully evaluated for each device designed to treat breast milk using UV-C irradiation.

Characterization of Thymol blue Radiochromic dosimeters for high dose applications

NASA Astrophysics Data System (ADS)

Aldweri, Feras M.; Abuzayed, Manar H.; Al-Ajaleen, Musab S.; Rabaeh, Khalid A.

2018-03-01

Thymol blue (TB) solutions and Thymol blue Polyvinyl Alcohol (TB-PVA) films have been introduced as Radiochromic dosimeter for high dose applications. The dosimeters were irradiated with gamma ray (60Co source) from 5 to 30 kGy for film, and from 0.150 kGy to 4 kGy for solution. The optical density of unirradiated and irradiated TB solution as well as TB-PVA film dosimeters were studied in terms of absorbance at 434 nm using UV/VIS spectrophotometer. The effects of scan temperature, light pre-gamma irradiation, dose rate, relative humidity and stability of the absorbance of solutions and films after irradiation were investigated. We found the dose sensitivity of TB solution and TB-PVA film dosimeters increases significantly with increases of the absorbed dose as well as with the increases of TB dye concentrations. The useful dose range of developed TB solutions and TB-PVA films dosimeters is in the range 0.125-1 kGy and of 5-20 kGy, respectively.

Relationship between high daily erythemal UV doses, total ozone, surface albedo and cloudiness: An analysis of 30 years of data from Switzerland and Austria

NASA Astrophysics Data System (ADS)

Rieder, H. E.; Staehelin, J.; Weihs, P.; Vuilleumier, L.; Maeder, J. A.; Holawe, F.; Blumthaler, M.; Lindfors, A.; Peter, T.; Simic, S.; Spichtinger, P.; Wagner, J. E.; Walker, D.; Ribatet, M.

2010-10-01

This work investigates the occurrence frequency of days with high erythemal UV doses at three stations in Switzerland and Austria (Davos, Hoher Sonnblick and Vienna) for the time period 1974-2003. While several earlier studies have reported on increases in erythemal UV dose up to 10% during the last decades, this study focuses on days with high erythemal UV dose, which is defined as a daily dose at least 15% higher than for 1950s clear-sky conditions (which represent preindustrial conditions with respect to anthropogenic chlorine). Furthermore, the influence of low column ozone, clear-sky/partly cloudy conditions and surface albedo on UV irradiance has been analyzed on annual and seasonal basis. The results of this study show that in the Central Alpine Region the number of days with high UV dose increased strongly in the early 1990s. A large fraction of all days with high UV dose occurring in the period 1974-2003 was found especially during the years 1994-2003, namely 40% at Davos, 54% at Hoher Sonnblick and 65% at Vienna. The importance of total ozone, clear-sky/partly cloudy conditions and surface albedo (e.g. in dependence of snow cover) varies strongly among the seasons. However, overall the interplay of low total ozone and clear-sky/partly cloudy conditions led to the largest fraction of days showing high erythemal UV dose. Furthermore, an analysis of the synoptic weather situation showed that days with high erythemal UV dose, low total ozone and high relative sunshine duration occur at all three stations more frequently during situations with low pressure gradients or southerly advection.

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

NASA Astrophysics Data System (ADS)

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

2008-05-01

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

Modifications in the optical and thermal properties of a CR-39 polymeric detector induced by high doses of γ-radiation

NASA Astrophysics Data System (ADS)

Saad, A. F.; Ibraheim, Mona H.; Nwara, Aya M.; Kandil, S. A.

2018-04-01

Effects of γ-radiation on the optical and thermal properties of a poly allyl diglycol carbonate (PADC), a form of CR-39, polymer have been investigated. CR-39 detectors were exposed to γ-rays at very high doses ranging from 5.0 × 105 to 3.0 × 106 Gy. The induced changes were analyzed using ultraviolet-visible spectroscopy (UV-VIS) in absorbance mode, and thermogravimetric analysis (TGA). The UV-visible spectra of the virgin and γ-irradiated CR-39 polymer detectors displayed a significant decreasing trend in their optical energy band gaps for indirect transitions, whereas for the direct ones showed a little change. This drop in the energy band gap with increasing dose is discussed on the basis of the gamma irradiation induced modifications in the CR-39 polymeric detector. The TGA thermograms show that the weight loss rate increased with increase in dose, which may be due to the disordered system via scission followed by crosslinking in the irradiated polymer detector. The TGA thermograms also indicated that the CR-39 detector decomposed in three/four stages for the virgin and irradiated samples. The activation energy for thermal decomposition was determined using a type of Arrhenius equation based on the TGA experimental results. These experimental results so obtained can be well used in radiation dosimetry.

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

PubMed

Keller, B; Zölzer, F; Kiefer, J

2004-01-01

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

Imprint Characteristics by Photo-Induced Solidification of Liquid Polymer

NASA Astrophysics Data System (ADS)

Komuro, Masanori; Taniguchi, Jun; Inoue, Seiji; Kimura, Naoya; Tokano, Yuji; Hiroshima, Hiroshi; Matsui, Shinji

2000-12-01

Nanoimprint lithography is an attractive technology for LSIs era below 40-nm critical dimension from the viewpoints of high-throughput and low-cost equipment. In order to avoid a pattern placement error due to thermal expansion in the conventional thermal imprint process, we attempted to replicate the mold pattern onto a liquid polymer, which was solidified using ultra-violet (UV) light irradiation at room temperature. The liquid polymer used here was supplied by TEIJIN SEIKI Co., and termed TSR-820. It was spin coated on slide glass to produce approximately 1.5-μm-thick polymer film. The thickness remained after UV exposure and rinsing in acetone was observed at the dose of 10 J/cm2 and it saturated about a UV exposure dose of 100 J/cm2 with an increase in the exposure dose. The mold fabricated of quartz plate was first pressed onto the polymer film at about 100 kg/cm2 and then the UV light was irradiated using an imprint apparatus developed for this work. After releasing the mold from the film, the substrate was rinsed in acetone to remove the residual liquid polymer. Eventually the minimum feature size of 100-nm line and 300-nm space pattern was successfully replicated in the polymer with good fidelity.

Study of formation of deep trapping mechanism by UV, beta and gamma irradiated Eu(3+) activated SrY2O4 and Y4Al2O9 phosphors.

PubMed

Dubey, Vikas; Kaur, Jagjeet; Parganiha, Yogita; Suryanarayana, N S; Murthy, K V R

2016-04-01

This paper reports the thermoluminescence properties of Eu(3+) doped different host matrix phosphors (SrY2O4 and Y4Al2O9). The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the crystallite size calculated by Scherer's formula. The prepared phosphor characterized by Scanning Electron Microscopic (SEM), Fourier Transform Infrared (FTIR), Energy Dispersive X-ray analysis (EDX), thermoluminescence (TL) and Transmission Electron Microscopic (TEM) techniques. The prepared phosphors for different concentration of Eu(3+) ions were examined by TL glow curve for UV, beta and gamma irradiation. The UV 254nm source used for UV irradiation, Sr(90) source was used for beta irradiation and Co(60) source used for gamma irradiation. SrY2O4:Eu(3+)and Y4Al2O9:Eu(3+) phosphors which shows both higher temperature peaks and lower temperature peaks for UV, beta and gamma irradiation. Here UV irradiated sample shows the formation of shallow trap (surface trapping) and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma, beta and UV exposure on TL studies was also examined and it shows linear response with dose which indicate that the samples may be useful for TL dosimetry. Formation of deep trapping mechanism by UV, beta and gamma irradiated Eu(3+) activated SrY2O4 and Y4Al2O9 phosphors is discussed in this paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modelling of photodegradation effect on elastic-viscoplastic behaviour of amorphous polylactic acid films

NASA Astrophysics Data System (ADS)

Belbachir, S.; Zaïri, F.; Ayoub, G.; Maschke, U.; Naït-Abdelaziz, M.; Gloaguen, J. M.; Benguediab, M.; Lefebvre, J. M.

2010-02-01

Polylactic acid (PLA) films were subjected to accelerated ultra-violet (UV) ageing. The UV irradiation leads to the alteration of the chemical structure which influences directly the mechanical response of the polymer. The chemical modification of the polymer was followed by gel permeation chromatography. Uniaxial tension tests were conducted at 50 °C and for different strain rates in order to characterize the large deformation response of PLA. The influence of UV irradiation on the alteration of the large deformation response of PLA was examined. A physically based elastic-viscoplastic model was used to describe the mechanical response of virgin PLA. The photodegradation effect was incorporated into the constitutive model to capture the stress-strain behaviour up to failure of aged PLA. To that end, the measured molecular weight was used as a direct input into the model. The model is shown to be in good agreement with experimental results over a wide range of UV irradiation doses.

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.

Evaluation of drug and sunscreen permeation via skin irradiated with UVA and UVB: comparisons of normal skin and chronologically aged skin.

PubMed

Hung, Chi-Feng; Fang, Chia-Lang; Al-Suwayeh, Saleh A; Yang, Shih-Yung; Fang, Jia-You

2012-12-01

Ultraviolet (UV) exposure is the predominant cause of skin aging. A systematic evaluation of drug skin permeation via photoaged skin is lacking. The aim of this work was to investigate whether UVA and UVB affect absorption by the skin of drugs and sunscreens, including tetracycline, quercetin, and oxybenzone. The dorsal skin of nude mice was subjected to UVA (24 and 39 J/cm(2)) or UVB (150, 200, and 250 mJ/cm(2)) irradiation. Levels of skin water loss, erythema, and sebum were evaluated, and histological examinations of COX-2 and claudin-1 expressions were carried out. Permeation of the permeants into and through the skin was determined in vitro using a Franz cell. In vivo skin uptake was also evaluated. Senescent skin (24 weeks old) was used for comparison. Wrinkling and scaling were significant signs of skin treated with UVA and UVB, respectively. The level of claudin-1, an indicator of tight junctions (TJs), was reduced by UVA and UVB irradiation. UVA enhanced tetracycline and quercetin skin deposition by 11- and 2-fold, respectively. A similar enhancement was shown for flux profiles. Surprisingly, a lower UVA dose revealed greater enhancement compared to the higher dose. The skin deposition and flux of tetracycline both decreased with UVB exposure. UVB also significantly reduced quercetin flux. The skin absorption behavior of chronologically aged skin approximated that of the UVA group, with photoaged skin showing higher enhancement. UV generally exhibited a negligible effect on modulating oxybenzone permeation. Skin disruption produced by UV does not necessarily result in enhanced skin absorption. It depends on the UV wavelength, irradiated energy, and physicochemical properties of the permeant. To the best of our knowledge, this is the first report establishing drug permeation profiles for UV-irradiated skin. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

UV irradiation experiments under simulated martian surface conditions: Bio-effects on glycine, phage T7 and isolated T7 DNA

NASA Astrophysics Data System (ADS)

Bérces, Attila; ten Kate, I. L.; Fekete, A.; Hegedus, M.; Garry, J. R. C.; Lammer, Helmut; Ehrenfreund, Pascale; Peeters, Zan; Kovacs, G.; Ronto, G.

Mars is considered as a main target for astrobiologically relevant exploration programmes. In order to explain the non-detection of organic material to a detection level of several parts per billion (ppb) by the Viking landers, several hypotheses have been suggested, including degradation processes occurring on the martian surface and in the martian soil and subsurface. UV exposure experiments have been performed in which thin layers of glycine ( 300 nm), and aqueous suspensions of phage T7 and isolated T7 DNA were irradiated with a Deuterium lamp and for comparison with a Xenon arc lamp, modified to simulate the solar irradiation on the surface of Mars (MarsUV). The glycine sample was subjected to 24 hours of irradiation with MarsUV. The results of this glycine experiment show a destruction rate comparable to the results of previous experiments in which thin layers of glycine were irradiated with a deuterium lamp (ten Kate et al., 2005, 2006). After exposure of different doses of simulated Martian UV radiation a decrease of the biological activity of phages and characteristic changes in the UV absorption spectrum have been detected, indicating the UV damage of isolated and intraphage T7 DNA. The results of our experiments show that intraphage DNA is 4 times more sensitive to simulated martian UV and deuterium lamp radiation than isolated T7 DNA. This result indicates the significant role that phage proteins play in the UV damage. The effect of simulated martian radiation is smaller than the biological defects observed after the exposure with a deuterium lamp for both cases, in intraphage and isolated DNA, despite of the 100 times larger intensity of the MarsUV lamp. The detected spectral differences are about ten times smaller; the biological activity is about 3 - 4 times smaller, indicating that the shorter wavelength UV radiation from the deuterium lamp is more effective in inducing DNA damage, irrespective of being intraphage or isolated.

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

Conjugation of (E)-5-[2-(Methoxycarbonyl)ethenyl]cytidine to hydrophilic microspheres: development of a mobile microscale UV light actinometer.

PubMed

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

2008-03-01

( E)-5-[2-(Methoxycarbonyl)ethenyl]cytidine was biotinylated through a diisopropylsilylacetal linkage and attached to the surface of hydrophilic streptavidin-coated microspheres through the high-affinity noncovalent interaction between biotin and streptavidin. The functionalized microspheres form a stable suspension in water. Upon UV irradiation, the nonfluorescent ( E)-5-[2-(methoxycarbonyl)ethenyl]cytidine on the microspheres undergoes photocyclization to produce highly fluorescent 3-beta-D-ribofuranosyl-2,7-dioxopyrido[2,3-d]pyrimidine. The fluorescence intensity of the microspheres can be correlated to the particle-specific UV doses applied at different suspension concentrations. The microspheres allow one to measure the UV dose (fluence) distribution in high-throughput water disinfection systems.

Electron beam irradiation for biological decontamination of Spirulina platensis

NASA Astrophysics Data System (ADS)

Brasoveanu, Mirela; Nemtanu, Monica; Minea, R.; Grecu, Maria Nicoleta; Mazilu, Elena; Radulescu, Nora

2005-10-01

The Cyanobacterium Spirulina is commercialized for its use in health foods and for therapeutic purposes due to its valuable constituents particularly proteins and vitamins. The aim of the paper is to study the Spirulina platensis behaviour when it is electron beam irradiated for biological decontamination. Microbial load, antioxidant activity, enzymatic inhibition, electron spin resonance (ESR) and UV-Vis spectra were measured for doses up to 80 kGy. The results were correlated with doses in order to find where decontamination is efficient, keeping the Spirulina qualities.

COBALT-60 Gamma Irradiation of Shrimp.

NASA Astrophysics Data System (ADS)

Sullivan, Nancy L. B.

Meta- and ortho-tyrosine were measured using high performance liquid chromatography (HPLC) in conjunction with electrochemical detection in shrimp irradiated using cobalt-60 gamma radiation in the absorbed dose range 0.8 to 6.0 kGy, in nonirradiated shrimp, and in bovine serum albumin (BSA) irradiated in dilute aqueous solution at 25.0 kGy. Ortho-tyrosine was measured in nonirradiated BSA. Para-, meta-, and ortho-tyrosine were measured using HPLC in conjunction with uv-absorption detection in dilute aqueous solutions of phenylalanine irradiated in the absorbed dose range 16.0 to 195.0 kGy. The measured yields of tyrosine isomers were approximately linear as a function of absorbed dose in shrimp, and in irradiated solutions of phenylalanine up to 37.0 kGy. The occurrence of meta- and ortho-tyrosine, which had formerly been considered unique radiolytic products, has not previously been reported in nonirradiated shrimp or BSA. The conventional hydrolyzation and analytical techniques used in the present study to measure meta- and ortho-tyrosine may provide the basis for a method to detect and determine the dose used in food irradiation.

Plasma Rich in Growth Factors Inhibits Ultraviolet B Induced Photoageing of the Skin in Human Dermal Fibroblast Culture.

PubMed

Anitua, Eduardo; Pino, Ander; Orive, Gorka

Ultraviolet irradiation is able to deeply penetrate into the dermis and alter fibroblast structure and function, leading to a degradation of the dermal extracellular matrix. The regenerative effect of plasma rich in growth factors (PRGF) on skin ageing was investigated using UVB photo-stressed human dermal fibroblasts as an in vitro culture model. PRGF was assessed over the main indicative features of ultraviolet B irradiation, including ROS formation, cell viability and death detection, apoptosis/ necrosis analysis and biosynthetic activity measurement. Four different UV irradiation protocols were tested in order to analyze the beneficial effects of PRGF. Ultraviolet irradiation exhibited a dose dependent cytotoxicity and dose of 400mJ/cm2 was selected for subsequent experiments. PRGF increased the cell viability and decreased the cell death comparing to the non-treated group. The apoptosis and necrosis were significantly lower in PRGF treated fibroblasts. ROS production after UV irradiation was significantly reduced in the presence of PRGF. Procollagen type I, hyaluronic acid and TIMP-1 levels were higher in the when treated with PRGF. This preliminary in vitro study suggests that PRGF is able to prevent UVB derived photooxidative stress and to diminish the cell damage caused by ultraviolet irradiation.

Airborne rhinovirus detection and effect of ultraviolet irradiation on detection by a semi-nested RT-PCR assay

PubMed Central

Myatt, Theodore A; Johnston, Sebastian L; Rudnick, Stephen; Milton, Donald K

2003-01-01

Background Rhinovirus, the most common cause of upper respiratory tract infections, has been implicated in asthma exacerbations and possibly asthma deaths. Although the method of transmission of rhinoviruses is disputed, several studies have demonstrated that aerosol transmission is a likely method of transmission among adults. As a first step in studies of possible airborne rhinovirus transmission, we developed methods to detect aerosolized rhinovirus by extending existing technology for detecting infectious agents in nasal specimens. Methods We aerosolized rhinovirus in a small aerosol chamber. Experiments were conducted with decreasing concentrations of rhinovirus. To determine the effect of UV irradiation on detection of rhinoviral aerosols, we also conducted experiments in which we exposed aerosols to a UV dose of 684 mJ/m2. Aerosols were collected on Teflon filters and rhinovirus recovered in Qiagen AVL buffer using the Qiagen QIAamp Viral RNA Kit (Qiagen Corp., Valencia, California) followed by semi-nested RT-PCR and detection by gel electrophoresis. Results We obtained positive results from filter samples that had collected at least 1.3 TCID50 of aerosolized rhinovirus. Ultraviolet irradiation of airborne virus at doses much greater than those used in upper-room UV germicidal irradiation applications did not inhibit subsequent detection with the RT-PCR assay. Conclusion The air sampling and extraction methodology developed in this study should be applicable to the detection of rhinovirus and other airborne viruses in the indoor air of offices and schools. This method, however, cannot distinguish UV inactivated virus from infectious viral particles. PMID:12525263

The photochemistry of pyrimidine in realistic astrophysical ices and the production of nucleobases

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

Nuevo, Michel; Materese, Christopher K.; Sandford, Scott A., E-mail: michel.nuevo-1@nasa.gov

2014-10-01

Nucleobases, together with deoxyribose/ribose and phosphoric acid, are the building blocks of DNA and RNA for all known life. The presence of nucleobase-like compounds in carbonaceous chondrites delivered to the Earth raises the question of an extraterrestrial origin for the molecules that triggered life on our planet. Whether these molecules are formed in interstellar/protostellar environments, in small parent bodies in the solar system, or both, is currently unclear. Recent experiments show that the UV irradiation of pyrimidine (C{sub 4}H{sub 4}N{sub 2}) in H{sub 2}O-rich ice mixtures that contain NH{sub 3}, CH{sub 3}OH, or CH{sub 4} leads to the formation ofmore » the pyrimidine-based nucleobases uracil, cytosine, and thymine. In this work, we discuss the low-temperature UV irradiation of pyrimidine in realistic astrophysical ice mixtures containing H{sub 2}O, CH{sub 3}OH, and NH{sub 3}, with or without CH{sub 4}, to search for the production of nucleobases and other prebiotic compounds. These experiments show the presence of uracil, urea, glycerol, hexamethylenetetramine, small amino acids, and small carboxylic acids in all samples. Cytosine was only found in one sample produced from ices irradiated with a higher UV dose, while thymine was not found in any sample, even after irradiation with a higher UV dose. Results are discussed to evaluate the role of the photochemistry of pyrimidine in the inventory of organic molecules detected in meteorites and their astrophysical/astrobiological implications.« less

Effects of ionizing radiations on a pharmaceutical compound, chloramphenicol

NASA Astrophysics Data System (ADS)

Varshney, L.; Patel, K. M.

1994-05-01

Chloramphenicol, a broad spectrum antibiotic, has been irradiated using Cobalt-60 γ radiation and electron beam at graded radiation doses upto 100 kGy. Several degradation products and free radicals are formed on irradiation. Purity, degradation products, free radicals, discolouration, crystallinity, solubility and entropy of radiation processing have been investigated. Aqueous solutions undergo extensive radiolysis even at low doses. Physico-chemical, microbiological and toxicological tests do not show significant degradation at sterilization dose. High performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), UV-spectrophotometry, diffuse reflectance spectroscopy (DRS) and electron spin resonance spectroscopy (ESR) techniques were employed for the investigations.

A study on radiation technological degradation of organic chloride wastewater--exemplified by TCE and PCE.

PubMed

Huang, Sheng-Kai; Hsieh, Ling-Ling; Chen, Chia-Chieh; Lee, Po-Hsiu; Hsieh, Bor-Tsung

2009-01-01

This paper describes the potential of using gamma radiation technology to degrade trichloroethylene (TCE) and perchloroethylene (PCE) wastewater. The experimental method is divided into two parts: (1) using the gamma-ray to irradiate the TCE and PCE solution, the dose-rate is 10Gy/minute, the irradiation dosage is 0-2.5kGy and (2) self-making the UV irradiation system, the tube specification is 254nm and 6W, and turning on 8 tubes at the same time to make the irradiation. The efficiency of degradation ratio for gamma-ray is better than UV in the range of 0.1-250ppm; for example, as for the concentration of 0.1ppm, when TCE is degraded to D(90) and T(90), the gamma-ray only needed 46.7Gy and took about 4.67 minutes, but UV needed to take about 28.1 minutes. The dose-concentration equations of TCE and PCE are: TCE: y=44.58+8.832x, R(2)=0.999; and PCE: y=81.33+12.81x, R(2)=0.997. We verified that the radiation technology is able to effectively degrade the organic chlorine wastewater without yielding the secondary pollution, and the TCE and PCE that degraded by using gamma-ray will be reached US-EPA and Taiwan Effluent Standard (5ppb).

Effects of γ-Irradiation on the Molecular Structures and Functions of Human Serum Albumin.

PubMed

Hu, Xinxin; Song, Wei; Li, Wei; Guo, Changying; Yu, Zehua; Liu, Rutao

2016-11-01

In this paper, we use spectroscopic methods (fluorescence spectroscopy, UV absorption spectroscopy, and circular dichroism (CD) spectroscopy) to elucidate the effects of reactive oxygen species generated by γ-irradiation on the molecular properties of human serum albumin (HSA). The results of fluorescence spectroscopy indicated that oxidation by γ-irradiation can lead to conformational changes of HSA. Data of CD spectra suggested that with the increase of radiation dose the percentage of α-helix in HSA has decreased. The determination of protein hydrophobicity showed that the effective hydrophobicity of HSA decreased up to 62% compared to the native HSA solution due to the exposure to the γ-irradiation. Furthermore, small changes in the esterase-like activity of HSA were introduced because of oxidation. The content of bityrosine increased markedly, suggesting that the oxidized HSA was aggregated. Moreover, there was no obvious change in the molecular properties of HSA with low γ-irradiation dose. Changes happened when the irradiation dose exceeded 200 Gy. © 2016 Wiley Periodicals, Inc.

Problems in Assessment of the UV Penetration into Natural Waters from Space-based Measurements

NASA Technical Reports Server (NTRS)

Vasilkov, Alexander P.; Herman, Jay; Krotkov, Nickolay A.; Kahru, Mati; Mitchell, B. Greg; Hsu, Christina; Bhartia, P. K. (Technical Monitor)

2002-01-01

Satellite instruments currently provide global maps of surface UV (ultraviolet) irradiance by combining backscattered radiance data with radiative transfer models. The models are often limited by uncertainties in physical input parameters of the atmosphere and surface. Global mapping of the underwater UV irradiance creates further challenges for the models. The uncertainties in physical input parameters become more serious because of the presence of absorbing and scattering quantities caused by biological processes within the oceans. In this paper we summarize the problems encountered in the assessment of the underwater UV irradiance from space-based measurements, and propose approaches to resolve the problems. We have developed a radiative transfer scheme for computation of the UV irradiance in the atmosphere-ocean system. The scheme makes use of input parameters derived from satellite instruments such as TOMS (Total Ozone Mapping Spectrometer) and SeaWiFS (Sea-viewing Wide Field-of-view Sensor). The major problem in assessment of the surface UV irradiance is to accurately quantify the effects of clouds. Unlike the standard TOMS UV algorithm, we use the cloud fraction products available from SeaWiFS and MODIS (Moderate Resolution Imaging Spectrometer) to calculate instantaneous surface flux at the ocean surface. Daily UV doses can be calculated by assuming a model of constant cloudiness throughout the day. Both SeaWiFS and MODIS provide some estimates of seawater optical properties in the visible. To calculate the underwater UV flux the seawater optical properties must be extrapolated down to shorter wavelengths. Currently, the problem of accurate extrapolation of visible data down to the UV spectral range is not solved completely, and there are few available measurements. The major difficulty is insufficient correlation between photosynthetic and photoprotective pigments of phytoplankton absorbing in the visible and UV respectively. We propose to empirically parameterize seawater absorption in the UV on a basis of available data sets of bio-optical measurements from a variety of ocean waters. Another problem is the lack of reliable data on pure seawater absorption in the UV. Laboratory measurements of the UV absorption of both pure water and pure seawater are required.

Photodegradation of pharmaceuticals and personal care products during UV and UV/H2O2 treatments.

PubMed

Kim, Ilho; Yamashita, Naoyuki; Tanaka, Hiroaki

2009-10-01

Photodegradation characteristics of pharmaceuticals and personal care products (PPCPs) and the effectiveness of H(2)O(2) addition for PPCPs photodegradation during UV treatment were examined in this study. Average k (1st order rate constant) value for all the PPCPs investigated increased by a factor of 1.3 by H(2)O(2) addition during UV treatment using biologically treated water (TW) spiked with the 30 PPCPs. Therefore, the effectiveness of H(2)O(2) addition for PPCPs removal during UV treatment in real wastewater treatment process was expected. It could be also known that H(2)O(2) addition would improve photodegradation rates of PPCPs highly resistant for UV treatment such as DEET, ethenzamide and theophylline. UV dose required for 90% degradation of each PPCP was calculated from k values obtained in UV and UV/H(2)O(2) treatment experiments using TW spiked with 30 PPCPs. For UV treatment, UV dose required for degrading each PPCP by 90% of initial concentration ranged from 38 mJ cm(-2) to 5644 mJ cm(-2), indicating that most of PPCPs will not be removed sufficiently in UV disinfection process in wastewater treatment plant. For UV/H(2)O(2) treatment, all the PPCPs except seven PPCPs including cyclophosphamide and 2-QCA were degraded by more than 90% by UV irradiation for 30 min (UV dose: 691 mJ cm(-2)), indicating that H(2)O(2) addition during UV treatment will be highly effective for improving the degradation of PPCPs by UV, even though much higher UV dose is still necessary comparing to for UV disinfection.

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.

Inactivation of Nonpathogenic Escherichia coli, Escherichia coli O157:H7, Salmonella enterica Typhimurium, and Listeria monocytogenes in Ice Using a UVC Light-Emitting Diode.

PubMed

Murashita, Suguru; Kawamura, Shuso; Koseki, Shigenobu

2017-07-01

Ice, widely used in the food industry, is a potential cause of food poisoning resulting from microbial contamination. Direct microbial inactivation of ice is necessary because microorganisms may have been present in the source water used to make it and/or may have been introduced due to poor hygiene during production or handling of the ice. Nonthermal and nondestructive microbial inactivation technologies are needed to control microorganisms in ice. We evaluated the applicability of a UVC light-emitting diode (UVC-LED) for microbial inactivation in ice. The effects of UV intensity and UV dose of the UVC-LED on Escherichia coli ATCC 25922 and a comparison of UVC-LED with a conventional UV lamp for effective bacterial inactivation in distilled water and ice cubes were investigated to evaluate the performance of the UVC-LED. Finally, we assessed the effects of the UVC-LED on pathogens such as E. coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ice cubes. The results indicated that UVC-LED effectiveness depended on the UV dose at all UV intensity conditions (0.084, 0.025, 0.013, 0.007, and 0.005 mW/cm 2 ) in ice and that UVC-LED could more efficiently inactivate E. coli ATCC 25922 in distilled water and ice than the UV lamp. At a UV dose of 2.64 mJ/cm 2 , E. coli in distilled water was decreased by 0.90 log CFU/mL (UV lamp) and by more than 7.0 log CFU/mL (UVC-LED). At 15.2 mJ/cm 2 , E. coli in ice was decreased by 3.18 log CFU/mL (UV lamp) and by 4.45 CFU/mL (UVC-LED). Furthermore, UVC-LED irradiation reduced the viable number of pathogens by 6 to 7 log cycles at 160 mJ/cm 2 , although the bactericidal effect was somewhat dependent on the type of bacteria. L. monocytogenes in ice was relatively more sensitive to UVC irradiation than were E. coli O157:H7 and Salmonella Typhimurium. These results demonstrate that UVC-LED irradiation could contribute to the safety of ice in the food industry.

Monitoring of solar-UV exposure among schoolchildren in five Japanese cities using spore dosimeter and UV-coloring labels.

PubMed

Munakata, N; Ono, M; Watanabe, S

1998-03-01

To monitor personal exposure to biologically effective solar-UV radiation, Bacillus subtilis spores on a membrane filter and UV-coloring labels were incorporated into a monitoring badge. The samples were covered with one of three types of filter sheet, dependent on the season, to reduce the amounts of exposure to measurable levels. Five fifth- or sixth-grade classes of primary schools, each consisting of 30-40 children, were chosen in northern (Sapporo), central (Tsukuba and Tokyo), and southern (Miyazaki and Naha) cities in Japan. In all four season, each child wore a badge on an upper arm for the entire waking hours, changing it daily, for a week. Upon collection of the badges, the survival of spores and the extent of coloration of the label were determined. The results were used to estimate the amount of daily exposure to biologically effective UV radiation, expressed as the value of spore inactivation dose. Unexpectedly, the average amounts of exposure were not directly correlated with the outdoor UV irradiance: in the two southern cities, despite high outdoor irradiance from spring to autumn, the average amounts of exposure were less than 3.1% of the average irradiance. Highly concentrated exposures occurred in two central cities on three days when extensive outdoor exercise took place. These results contradict the simple notion that children's exposure is in proportion to the outdoor UV irradiance, and support the view that the extent of solar-UV exposure is primarily determined by life-style rather than living location.

Effect of laser irradiation on the functional activity of enzymes with different structural complexity

NASA Astrophysics Data System (ADS)

Ostrovtsova, Svetlana A.; Volodenkov, Alexander P.; Maskevich, Alexander A.; Artsukevich, Irina M.; Anufrik, Slavomir S.; Makarchikov, Alexander F.; Chernikevich, Ivan P.; Stepuro, Vitali I.

1998-05-01

Three enzymes differing in their structural composition were irradiated by UV lasers to study the effect of temperature, protein concentration and addition of small molecules on their sensitivity to radiation exposure. The laser-induced effects were due to the structural complexity of the protein molecules and depended on the dose applied, the wavelength and the density of irradiation. The multi-enzyme 2- oxoglutarate dehydrogenase complex was subjected to pronounced irradiation-induced changes whereas the response of the two other enzymes was less significant. Reduction of the protein levels in irradiated samples was important under the XeCl laser coercion and the effects depended on the doses applied. The laser irradiation effects are suggested to be realized by means of conformational changes in the protein molecules and intermolecular association- dissociation processes.

Study of The Non-linear Uv Dosimetry In Simulated Extraterrestrial Conditions

NASA Astrophysics Data System (ADS)

Berces, A.; Kerekgyarto, T.; Ronto, G.; Lammer, H.; Kargl, G.; Komle, N. I.

In UV biological dosimetry the UV dose scale is additive starting at a value of zero ac- cording to the definition of CIE (Technical Report TC-6-18). The biological dose can be defined by a measured end-effect. In our dosimeters (phage T7 and uracil dosime- ter) exposed to natural (terrestrial) UV radiation the proportion of pyrimidin photo- products among the total photoproducts is smaller than 10 and the linear correlation between the biological and physical dose is higher than 0.9. According to the experi- mental data this linear relationship is often not valid. We observed that UV radiation did not only induce dimerisation but shorter wavelengths caused monomerisation of pyrimidin dimers. Performing the irradiation in oxygen free environment and using a Deuterium lamp as UV source, we could increase monomerisation against dimerisa- tion thus the DNA-based dosimetrySs additivity rule is not fulfilled in these conditions. In this study we will demonstrate those non-linear experiments which constitute the basis of our biological experiments on the International Space Station.

Flares and habitability

NASA Astrophysics Data System (ADS)

Abrevaya, Ximena C.; Cortón, Eduardo; Mauas, Pablo J. D.

2012-07-01

At present, dwarf M stars are being considered as potential hosts for habitable planets. However, an important fraction of these stars are flare stars, which among other kind of radiation, emit large amounts of UV radiation during flares, and it is unknown how this events can affect life, since biological systems are particularly vulnerable to UV. In this work we evaluate a well known dMe star, EV Lacertae (GJ 873) as a potential host for the emergence and evolution of life, focusing on the effects of the UV emission associated with flare activity. Since UV-C is particularly harmful for living organisms, we studied the effect of UV-C radiation on halophile archaea cultures. The halophile archaea or haloarchaea are extremophile microorganisms, which inhabit in hypersaline environments and which show several mechanisms to cope with UV radiation since they are naturally exposed to intense solar UV radiation on Earth. To select the irradiance to be tested, we considered a moderate flare on this star. We obtained the mean value for the UV-C irradiance integrating the IUE spectrum in the impulsive phase, and considering a hypothetical planet in the center of the liquid water habitability zone. To select the irradiation times we took the most frequent duration of flares on this star which is from 9 to 27 minutes. Our results show that even after considerable UV damage, the haloarchaeal cells survive at the tested doses, showing that this kind of life could survive in a relatively hostile UV environment.

Photo-Oxidation Products of Skin Surface Squalene Mediate Metabolic and Inflammatory Responses to Solar UV in Human Keratinocytes

PubMed Central

Kostyuk, Vladimir; Potapovich, Alla; Stancato, Andrea; De Luca, Chiara; Lulli, Daniela; Pastore, Saveria; Korkina, Liudmila

2012-01-01

The study aimed to identify endogenous lipid mediators of metabolic and inflammatory responses of human keratinocytes to solar UV irradiation. Physiologically relevant doses of solar simulated UVA+UVB were applied to human skin surface lipids (SSL) or to primary cultures of normal human epidermal keratinocytes (NHEK). The decay of photo-sensitive lipid-soluble components, alpha-tocopherol, squalene (Sq), and cholesterol in SSL was analysed and products of squalene photo-oxidation (SqPx) were quantitatively isolated from irradiated SSL. When administered directly to NHEK, low-dose solar UVA+UVB induced time-dependent inflammatory and metabolic responses. To mimic UVA+UVB action, NHEK were exposed to intact or photo-oxidised SSL, Sq or SqPx, 4-hydroxy-2-nonenal (4-HNE), and the product of tryptophan photo-oxidation 6-formylindolo[3,2-b]carbazole (FICZ). FICZ activated exclusively metabolic responses characteristic for UV, i.e. the aryl hydrocarbon receptor (AhR) machinery and downstream CYP1A1/CYP1B1 gene expression, while 4-HNE slightly stimulated inflammatory UV markers IL-6, COX-2, and iNOS genes. On contrast, SqPx induced the majority of metabolic and inflammatory responses characteristic for UVA+UVB, acting via AhR, EGFR, and G-protein-coupled arachidonic acid receptor (G2A). Conclusions/Significance Our findings indicate that Sq could be a primary sensor of solar UV irradiation in human SSL, and products of its photo-oxidation mediate/induce metabolic and inflammatory responses of keratinocytes to UVA+UVB, which could be relevant for skin inflammation in the sun-exposed oily skin. PMID:22952984

Variations in total ozone column and biologically effective solar UV exposure doses in Bologna, Italy during the period 2005-2010

NASA Astrophysics Data System (ADS)

Petkov, Boyan; Vitale, Vito; Tomasi, Claudio; Mazzola, Mauro; Lanconelli, Christian; Lupi, Angelo; Busetto, Maurizio

2014-01-01

Variations in total ozone column and sun exposures able to cause erythema and damage the DNA molecules were observed by the narrow-band filter radiometer UV-RAD in Bologna, Italy from 2005 to 2010. The ozone columns determined from the UV-RAD measurements were found to be close to those provided by the satellite Ozone Monitoring Instrument (OMI) showing an average discrepancy of 1 % with standard deviation of ± 6 %. Analysis of the data highlights a well-marked annual cycle of the ozone column variations while the oscillations with periods of 8, 18 and 34 months present much smaller amplitudes. The influence of the frequency of solar irradiance measurements on the accuracy of the evaluated daily exposure dose has been studied and it was found that time intervals no longer than 5-10 min between the measurements of erythema and DNA damage effective UV irradiances provide a satisfactory assessment of the corresponding daily exposures. The latter do not present significant year-to-year variations for the period under study, while their annual distributions show slight changes likely due to the specific cloud cover and ozone column variability for different years. The annual erythemal exposure dose for 2007-2010 varied between 603.7 and 638.1 kJ m-2, while the corresponding sun exposure affecting DNA changed from 6.38 to 7.91 kJ m-2.

Estimated UV doses to psoriasis patients during climate therapy at Gran Canaria in March 2006

NASA Astrophysics Data System (ADS)

Nilsen, L. T. N.; Søyland, E.; Krogstad, A. L.

2008-01-01

Psoriasis is a chronic inflammatory disease involving about 2-3% of the Norwegian population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV) radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun exposure and these biological effects is not well known. In March 2006 a study was carried out to investigate possible therapeutic outcome mechanisms in 20 psoriasis patients receiving climate therapy at Gran Canaria. This paper presents estimates of their individual skin UV-doses based on UV measurements and the patients' diaries with information on time spent in the sun. On the first day of exposure the patients received on average 5.1 Standard Erythema Doses (SED: median=4.0 SED, range 2.6-10.3 SED) estimated to the skin. During the 15 days study they received 165.8 SED (range 104.3-210.1 SED). The reduction in PASI score was 72.8% on average, but there was no obvious relation between the improvement and the UV dose. The UV doses were higher than those found from climate therapy studies at other locations. It seems beneficial to use more strict exposure schedules that consider the available UV irradiance, depending on time of the day, time of the year and weather conditions.

UV-induced isomerization of oral retinoids in vitro and in vivo in hairless mice.

PubMed

Berne, B; Rollman, O; Vahlquist, A

1990-08-01

Ultraviolet (UV) irradiation causes isomerization and destruction of many vitamin A analogues (retinoids). Using high-performance liquid chromatography (HPLC), we investigated in vitro and in vivo the effects of UV irradiation on 2 all-trans aromatic retinoids (etretinate and acitretin) and on 13-cis retinoic acid (isotretinoin). When etretinate and acitretin dissolved in ethanol were irradiated with UVB (280-320 nm; 10-336 mJ/cm2) or UVA (320-400 nm; 1-5 J/cm2), extensive and reproducible cis-isomerizations occurred at the 13-position (cis/trans ratio approximately 1.6 in all experiments) but there was no progressive photodegradation of the molecules. Irradiation of isotretinoin produced only moderate trans-isomerization but the sum of HPLC peak heights fell with increasing UV doses, being 72% of the original value after 336 mJ/cm2 of UVB. Hairless mice were given etretinate (50 mg/kg bw), acitretin (200 mg/kg) or isotretinoin (50 mg/kg) on days 1, 4 and 7 and were irradiated daily for 8 d with 13 mJ/cm2 UVB plus 1 J/cm2 UVA. Samples of serum, dorsal skin and liver were collected and retinoids analyzed by HPLC. In the etretinate and acitretin-treated, irradiated animals the serum concentrations of the 13-cis isomers were 2-6 times higher than in nonirradiated controls. Irradiated epidermis also contained significantly higher concentrations of 13-cis etretinate and 13-cis acitretin than did control epidermis. The serum and epidermal concentrations of all-trans etretinate and acitretin were unchanged or even increased after irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on activated cytostatic fluorouracil as photosensitizer: to use in eye tumor treatment

NASA Astrophysics Data System (ADS)

Pascu, Mihail-Lucian; Carstocea, Benone D.; Brezeanu, Mihail; Voicu, Letitia; Staicu, Angela; Gazdaru, Doina M.; Pascu, Ruxandra A.

2004-09-01

Hydroxypyrimidine 5-fluorouracil (5-FU) belongs to the cytostatics group known as antimetabolites. The effect of UV irradiation on 5-FU was investigated by absorption and fluorescence spectroscopy. The study of the photosensitizer properties of 5-FU was made since their effects could be enhanced by exposure to UV radiation at different doses. Solutions 2.5x10-4M in natural saline water (0.8% NaCl), irradiated with optical beams emitted by N2 laser and UV Hg classic lamp, were used. The 5-FU was chosen due to its strong absorption along a large spectral range which makes possible the fluorescence excitation in UV. The absorption spectra exhibit bands between 250 - 450 nm. The emission fluorescence was measured in the 400-550 nm spectral range, with λex=320 and 350 nm for samples irradiated with Hg lamp and with λex=360 nm for samples irradiated with N2 laser. The excitation fluorescence was measured in the spectral range 200-400 nm, with λem=440 nm for samples irradiated with N2 laser. The spectra reveal a fluorescence enhancement with the exposure time, with a maximum at 3 min due to the transformation of 5-FU molecule into a fluorescent tautomeric form. The destruction more rapid than usual of the neovascularisation was observed for conjunctive of rabbit eyes, when they are impregnated with 5-FU solution and exposed to incoherent UV and visible light.

The effect of single and repeated UVB radiation on rabbit cornea.

PubMed

Fris, Miroslav; Tessem, May-Britt; Cejková, Jitka; Midelfart, Anna

2006-12-01

Cumulative effect of ultraviolet radiation (UVR) is an important aspect of UV corneal damage. The purpose of this study was to apply high resolution magic angle spinning proton nuclear magnetic resonance (HR-MAS 1H NMR) spectroscopy to evaluate the effect of single and repeated UV radiation exposure of the same overall dose on the rabbit cornea. Corneal surfaces of 24 normal rabbit eyes were examined for the effects of UVB exposure (312 nm). In the first group (UVB1), animals were irradiated with a single dose (3.12 J/cm2; 21 min) of UVB radiation. The animals in the second group (UVB2) were irradiated three times for 7 min every other day (dose of 1.04 J/cm2; days 1, 3, 5) to give the same overall dose (3.12 J/cm2). The third group served as an untreated control group. One day after the last irradiation, the animals were sacrificed, and the corneas were removed and frozen. HR-MAS 1H NMR spectra from intact corneas were obtained. Special grouping patterns among the tissue samples and the relative percentage changes in particular metabolite concentrations were evaluated using modern statistical methods (multivariate analysis, one-way ANOVA). The metabolic profile of both groups of UVB-irradiated samples was significantly different from the control corneas. Substantial decreases in taurine, hypo-taurine and choline-derivatives concentrations and substantial elevation in glucose and betaine levels were observed following the UVR exposure. There was no significant difference between the effect of a single and repeated UVB irradiation of the same overall dose. For the first time, the effects of single and repeated UVR doses on the metabolic profile of the rabbit cornea were analysed and compared. The combination of HR-MAS 1H NMR spectroscopy and modern statistical methods (multivariate analysis, one-way ANOVA) proved suitable to assess the overall view of the metabolic alterations in the rabbit corneal tissue following UVB radiation exposure.

Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry.

PubMed

Sahoo, G S; Paul, S; Tripathy, S P; Sharma, S C; Jena, S; Rout, S; Joshi, D S; Bandyopadhyay, T

2014-12-01

Effects of high-dose neutron irradiation on chemical and optical properties of CR-39 were studied using FTIR (Fourier Transform Infrared) and UV-vis (Ultraviolet-Visible) spectroscopy. The primary goal was to find a correlation between the neutron dose and the corresponding changes in the optical and chemical properties of CR-39 resulted from the neutron irradiation. The neutrons were produced by bombarding a thick Be target with 22-MeV protons. In the FTIR spectra, prominent absorbance peaks were observed at 1735cm(-1) (C=O stretching), 1230cm(-1)(C-O-C stretching), and 783cm(-1)(=C-H bending), the intensities of which decreased with increasing neutron dose. The optical absorbance in the visible range increased linearly with the neutron dose. Empirical relations were established to estimate neutron doses from these optical properties. This technique is particularly useful in measuring high doses, where track analysis with an optical microscope is difficult because of track overlapping. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genetic Effects of Uv Irradiation on Excision-Proficient and -Deficient Yeast during Meiosis

PubMed Central

Resnick, Michael A.; Game, John C.; Stasiewicz, Stanley

1983-01-01

The lethal and recombinational responses to ultraviolet light irradiation (UV) by excision-proficient (RAD+) and deficient strains (rad1) of Saccharomyces cerevisiae has been examined in cells undergoing meiosis. Cells that exhibit high levels of meiotic synchrony were irradiated either at the beginning or at various times during meiosis and allowed to proceed through meiosis. Based on survival responses, the only excision repair mechanism for UV damage available during meiosis is that controlled by the RAD1 pathway. The presence of pyrimidine dimers at the beginning of meiosis does not prevent cells from undergoing meiosis; however, the spore products exhibit much lower survival than cells from earlier stages of meiosis. The reduced survival is probably due to effects of UV on recombination. Meiotic levels of gene conversion are reduced only two to three times in these experiments; however, intergenic recombination is nearly abolished after a dose of 4 J/m 2 to the rad1 strain. Exposure to 25 J/m2 had little effect on the wild-type strain. Since normal meiotic reciprocal recombination is generally considered to involve gene conversion-type intermediates, it appears that unrepaired UV damage dissociates the two processes. These results complement those obtained with the mei-9 mutants of Drosophila which also demonstrate a dissociation between gene conversion and reciprocal recombination. These results are consistent with molecular observations on the UV-irradiated rad1 strain in that there is no excision of pyrimidine dimers or exchange of dimers during meiosis. PMID:6352405

Effects of ultraviolet-B radiation on the growth, physiology and cannabinoid production of Cannabis sativa L

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

Lydon, J.

The concentration of cannabinoids in Cannabis sativa L. is correlated with high ultraviolet-B (UV-B) radiation environments. ..delta../sup 9/-Tetrahydrocannabinolic acid and cannabidiolic acid, both major secondary products of C. sativa, absorb UV-B radiation and may function as solar screens. The object of this study was to test the effects of UV-B radiation on the physiology and cannabinoid production of C. sativa. Drug and fiber-type C. sativa were irradiated with three levels of UV-B radiation for 40 days in greenhouse experiments. Physiological measurements on leaf tissues were made by infra-red gas analysis. Drug and fiber-type control plants had similar CO/sub 2/ assimilationmore » rates from 26 to 32/sup 0/C. Drug-type control plant had higher dark respiration rates and stomatal conductances than fiber-type control plants. The concentration of ..delta../sup 9/-THC, but not of other cannabinoids) in both vegetative and reproductive tissues increased with UV-B dose in drug-type plants. None of the cannabinoids in fiber-type plants were affected by UV-B radiation. The increased level of ..delta../sup 9/-THC found in leaves after irradiation may account for the physiological and morphological insensitivity to UV-B radiation in the drug-type plants. However, fiber plants showed no comparable change in the level of cannabidoil (CBD). Resin stripped form fresh fiber-type floral tissue by sonication was spotted on filter paper and irradiated continuously for 7 days. Cannabidiol (CBD) gradually decreased when irradiated but ..delta../sup 9/-THC and cannabichromene did not.« less

Evaluation of thrombogenicity of beta-propiolactone/ultraviolet (beta-PL/UV) treated PPSB in chimpanzees

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

Kotitschke, R.; Stephan, W.; Prince, A.M.

1983-05-01

The thrombogenicity of beta-PL/UV-treated PPSB (factor IX concentrate) was evaluated in chimpanzees. PPSB isolated from beta-propiolactone-treated and UV-irradiated plasma was injected into chimpanzees at a dose of approximately 100 units/kg body weight. An FDA licensed PPSB preparation served as the negative control, and a preparation containing activated as well as precursor clotting factors served as the positive control. 15 minutes, 1 h, 4 h, and 24 h after the PPSB application the following parameters were determined in the chimpanzee blood: factors II, VII, IX, X, VIII, fibrinogen, AT III, thrombin coagulase, Quick value, APTT and platelet count. Neither the untreatedmore » control preparation, nor the PPSB isolated from beta-propiolactone-treated and UV-irradiated plasma, showed signs of thrombogenicity in the chimpanzee model. The positive control indicated that the chimpanzee is a suitable model for the thrombogenicity testing of activated clotting factors.« less

Improved Extraction and Quality Characterization of Water-Soluble Polysaccharide from Gamma-Irradiated Lentinus edodes.

PubMed

Akram, Kashif; Shahbaz, Hafiz Muhammad; Kim, Gui-Ran; Farooq, Umar; Kwon, Joong-Ho

2017-02-01

Gamma irradiation was applied to the improved extraction of water-soluble polysaccharides (WSPs) from dried Lentinus edodes. Irradiation provided a dose-dependent increase in extraction yield (0 kGy, 2.01%; 7.5 kGy, 4.03%; 15 kGy, 7.17%) and purity (0 kGy, 78.8%; 7.5 kGy, 83.1%; 15 kGy, 85.6%) of the WSPs from hot-water extraction. The effect of irradiation was evident in the degraded microstructures and reduced molecular weights of the WSPs. However, nuclear magnetic resonance, Fourier-transform infrared, and X-ray diffraction spectroscopic analyses provided comparable structures of WSPs from nonirradiated and irradiated samples. UV-visible spectra showed a dose-dependent decline in intensity, but an improvement in thermal properties of the WSPs from the irradiated mushroom samples was observed. © 2017 Institute of Food Technologists®.

[On Individualization of Therapeutic Doses of Optical Radiation according to Changes in Parameters of Blood Oxygenation].

PubMed

Zalesskaya, G A

2015-01-01

The effect of in vivo laser irradiation by optical radiation on blood from different patients is studied. The objects of research were three series of blood samples from patients whose treatment course included extracorporeal UV blood irradiation, intravenous laser blood irradiation and supra-venous blood laser irradiation. Before and after irradiation the results on optic oximetry and gas content of venous blood were compared. The results of positive and negative influence of blood irradiation on characteristics of an oxygen exchange in separate patients and on the maintenance of some products of metabolism are represented. It is shown that at the same power dose, their changes depend on individual, initial values of hemoglobin oxygen saturation of venous blood and its photoinduced changes which objectively reflect individual sensitivity of patients to the action of optical radiation on blood and can be used for assessment of the efficiency of phototherapy.

Ultralow dose effects in ion-beam induced grafting of polymethylmethacrylate (PMMA)

NASA Astrophysics Data System (ADS)

Corelli, J. C.; Steckl, A. J.; Pulver, D.; Randall, J. N.

We have investigated the process of image enhancement in high resolution lithography through polymer grafting techniques. Sensitivity gains of 10 3-10 4 were obtained for H +, X-ray, e-beam and deep-UV irradiations. Ultralow dose effects in 60 keV H + irradiated PMMA have been observed through the use of the acrylic acid (AA) monomer grafting with irradiated PMMA. At conventional doses of 10 10 cm -2 an inner structure of each feature is revealed. At doses of (1-2) X 10 9 cm -2, discrete events within the exposed regions are observable. This is the first time that individual events have been observable in a lithography process and sets the upper limit in the useful sensitivity of the resist and ion lithography process. This effect is directly observable only with ions, because of their higher efficiency per particle than either photons or electrons.

Granzyme B mediates both direct and indirect cleavage of extracellular matrix in skin after chronic low-dose ultraviolet light irradiation

PubMed Central

Parkinson, Leigh G; Toro, Ana; Zhao, Hongyan; Brown, Keddie; Tebbutt, Scott J; Granville, David J

2015-01-01

Extracellular matrix (ECM) degradation is a hallmark of many chronic inflammatory diseases that can lead to a loss of function, aging, and disease progression. Ultraviolet light (UV) irradiation from the sun is widely considered as the major cause of visible human skin aging, causing increased inflammation and enhanced ECM degradation. Granzyme B (GzmB), a serine protease that is expressed by a variety of cells, accumulates in the extracellular milieu during chronic inflammation and cleaves a number of ECM proteins. We hypothesized that GzmB contributes to ECM degradation in the skin after UV irradiation through both direct cleavage of ECM proteins and indirectly through the induction of other proteinases. Wild-type and GzmB-knockout mice were repeatedly exposed to minimal erythemal doses of solar-simulated UV irradiation for 20 weeks. GzmB expression was significantly increased in wild-type treated skin compared to nonirradiated controls, colocalizing to keratinocytes and to an increased mast cell population. GzmB deficiency significantly protected against the formation of wrinkles and the loss of dermal collagen density, which was related to the cleavage of decorin, an abundant proteoglycan involved in collagen fibrillogenesis and integrity. GzmB also cleaved fibronectin, and GzmB-mediated fibronectin fragments increased the expression of collagen-degrading matrix metalloproteinase-1 (MMP-1) in fibroblasts. Collectively, these findings indicate a significant role for GzmB in ECM degradation that may have implications in many age-related chronic inflammatory diseases. PMID:25495009

On induced-modifications in optical properties of Makrofol® DE 1-1 SSNTD by UVB and UVA

NASA Astrophysics Data System (ADS)

Al-Amri, A.; El Ghazaly, M.; Abdel-Aal, M. S.

The induced modifications in the optical properties of Makrofol® DE 1-1 solid state nuclear track detectors upon irradiation by UVB (302 nm) and UVA (365 nm) were characterized and compared. Makrofol® DE 1-1 detectors were irradiated separately for different durations with UVB (302 nm) and UVA (365 nm). The measurements revealed insignificant changes were observed at all in UVA (365 nm)-irradiated Makrofol® DE 1-1, irrespective the irradiation time (dose). All UVB (302 nm)-irradiated Makrofol® DE 1-1 detectors show a substantial red shift in UV-Vis spectra and a continuous increase in absorbance as the exposure time (Dose) to UVB increases. UVC-irradiated Makrofol® DE 1-1 exhibits absorption bands at 315 ± 5 nm in UV-visible spectra. The absorption increases exponential with the increasing the UVB irradiation time gets saturated started from 75 h to 400 h. In the visible light range no significant changes were observed in Makrofol® DE 1-1 detector irrespective the exposure time to UVB of 302 nm. It is found that the direct band gap is higher than indirect band gap and both decrease with the increase in the irradiation time of UVB of 302 nm. The obtained results of the Urbach energy and carbon atoms per cluster indicate that both increase with the increase in the irradiation time to UVB (302 nm). The induced modification in the optical properties of Makrofol® DE 1-1 can be used in UVB dosimetry, meanwhile it is not applicable for UVA of 365 nm.

Correction of nonuniformity error of Gafchromic EBT2 and EBT3.

PubMed

Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Yabunaka, Kouichi

2016-05-08

This study investigates an X-ray dose measurement method for computed tomography using Gafchromic films. Nonuniformity of the active layer is a major problem in Gafchromic films. In radiotherapy, nonuniformity error is reduced by applying the double-exposure technique, but this is impractical in diagnostic radiology because of the heel effect. Therefore, we propose replacing the X-rays in the double-exposure technique with ultraviolet (UV)-A irradiation of Gafchromic EBT2 and EBT3. To improve the reproducibility of the scan position, Gafchromic EBT2 and EBT3 films were attached to a 3-mm-thick acrylic plate. The samples were then irradiated with a 10 W UV-A fluorescent lamp placed at a distance of 72cm for 30, 60, and 90 minutes. The profile curves were evaluated along the long and short axes of the film center, and the standard deviations of the pixel values were calculated over large areas of the films. Paired t-test was performed. UV-A irradiation exerted a significant effect on Gafchromic EBT2 (paired t-test; p = 0.0275) but not on EBT3 (paired t-test; p = 0.2785). Similarly, the homogeneity was improved in Gafchromic EBT2 but not in EBT3. Therefore, the double-exposure technique under UV-A irradiation is suitable only for EBT2 films.

Catalytic degradation of Amlodipine Besylate using ZnO, Cu doped ZnO, and Fe doped ZnO nanoparticles from an aqueous solution: Investigating the effect of different parameters on degradation efficiency

NASA Astrophysics Data System (ADS)

Alizadeh, Elahe; Baseri, Hadi

2018-04-01

Some common nanoparticles, such as Zinc Oxide have been used as nanocatalysts in many processes, but they also have an important application in water purification processes. In this research, ZnO based nanoparticles were used for the degradation of Amlodipine Besylate (AMB) and the effect of some main parameters, e.g. initial concentration of AMB, nanocatalysts dose, pH of the solution, temperature of the solution, H2O2 dose, and the time of visible light irradiation, were investigated. The destruction amount was determined by UV-Vis spectroscopy. The synthesized nanoparticles were characterized by FE-SEM, XRD, FT-IR, BET, BJH, EDS, XRF and UV-Vis techniques. The maximum degradation of AMB was about 90% in 60 min of visible light irradiation with 100 μL of H2O2.

New stable perfluoroallyl radical from perfluoro-2,4-dimethyl-3-ethylpentene-2 and its photoconversion reactions

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

Shvedova, M.K.; Allayarov, S.R.; Barkalov, I.M.

1988-05-01

The thermally and chemically stable perfluoroally radical is formed in the radiolysis of perfluoro-2, 4-dimethyl-3-ethylpentene-2. A phototransformation of this radical into other radicals takes place under the action of UV light (/lambda/ < 300 nm) which are thermally unstable. Samples containing up to 90% FMP and 10% of its isomers were placed into ampules made of quartz or SK-4B glass, which gave to EPR signal after irradiation; the ampules were evacuated to a pressure of 0.13 Pa, frozen to 77 K, and irradiated with /sup 60/Co /lambda/-quanta at 77 K with doses up to 200 kGy. Irradiation with UV lightmore » was performed at 77 K with light from a DRSh-1000 lamp.« less

Evaluation of colorless polyimide film for thermal control coating applications

NASA Technical Reports Server (NTRS)

St.clair, A. K.; Slemp, W. S.

1985-01-01

A series of essentially colorless aromatic polyimide films was synthesized and characterized with the objective of obtaining maximum optical transparency for applications in space. Optical transparency is a requirement for high performance polymeric films used in second surface mirror coatings on thermal control systems. The intensity in color of aromatic polyimide films was lowered by reducing the electronic interaction between chromophoric centers in the polymer molecular structure and by using highly purified monomers. The resulting lightly colored to colorless polyimide films were characterized by UV-visible and infrared spectroscopy before and after exposure to 300 equivalent solar hours UV irradiation and varying doses of 1 MeV electron irradiation. After irradiation, the films were found to be 2 to 2.5 times more transparent than commercial polyimide film of the same thickness.

Hydrodynamic cavitation to improve bulk fluid to surface mass transfer in a nonimmersed ultraviolet system for minimal processing of opaque and transparent fluid foods.

PubMed

Milly, P J; Toledo, R T; Chen, J; Kazem, B

2007-11-01

Ultraviolet (UV)-induced chemical reactions and inactivation of microorganisms in transparent and opaque fluids are strongly dependent upon the homogenous exposure of the target species to the UV irradiation. Current UV technologies used in water disinfection and food preservation applications have limited efficacy due to suspended particles shading target species. An Ultraviolet-Shockwave Power Reactor (UV-SPR) consisting of an inner rotating rotor and a stationary quartz housing and 2 end plates was used to induce 'controlled cavitation.' Eight UV low-pressure mercury lamps spaced uniformly were installed lengthwise around the quartz housing periphery. A KI to I(3) (-)chemical dosimeter for UV was used to quantify photons received by fluid in the annular space of the SPR. UV dose (J/m(2)) increased from 97 J/m(2) at 0 rpm to over 700 J/m(2) for SPR speeds above 2400 rpm. Inactivation of E. coli 25922 in apple juice and skim milk in the UV-SPR at exit temperatures below 45 degrees C was greater than 4.5 and 3 logs, respectively. The UV-SPR system proved successful in increasing the mass transfer of transparent and opaque fluid to the UV irradiated surface.

Response of biological uv dosimeters to the simulated extraterrestrial uv radiation

NASA Astrophysics Data System (ADS)

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

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

DSC studies on gamma irradiated poly(vinylidene fluoride) applied to high gamma dose dosimetry

NASA Astrophysics Data System (ADS)

Batista, Adriana S. M.; Faria, Luiz O.

2017-11-01

Poly(vinylidene fluoride) homopolymer (PVDF) was investigated for use on high gamma dose dosimetry. Samples were irradiated with gamma doses ranging from 100 kGy to 3000 kGy. Differential scanning calorimetry (DSC) was used to construct an unambiguous relationship between the melting transition latent heat (LM) and the absorbed dose (D). DSC thermograms were taken immediately, 1, 2 and 8 months after the irradiation process revealing that the LMx D relationship presented no change for doses ranging from 100 to 2750 kGy. FTIR and UV-Vis spectroscopy data revealed the radio-induction of C˭O and C˭C bonds. These radio-induced bonds were responsible by the chain stiffening and chain oxidation, respectively. SEM microscopy demonstrates that the spherulitic large crystalline structures present in pristine PVDF are destroyed with doses as low as 100 kGy. The DRX analysis revealed that the main effect of high gamma doses in the crystalline structure of PVDF is to provoke a change from the pristine PVDF α-phase to the γ-phase. Both the ability to detect gamma doses in a large dose range and the low fading features make PVDF homopolymers good candidates to be investigated as high gamma dose dosimeters.

Microbial diversity of Indian Ocean hydrothermal vent plumes: microbes tolerant of desiccation, peroxide exposure, and ultraviolet and gamma-irradiation.

PubMed

La Duc, Myron T; Benardini, James N; Kempf, Michael J; Newcombe, David A; Lubarsky, Michael; Venkateswaran, Kasthuri

2007-04-01

The microbial diversity of Kali chimney plumes, part of a hydrothermal vent field in the Rodriguez Triple Junction, Indian Ocean (depth approximately 2,240 m), was examined in an attempt to discover "extremotolerant" microorganisms that have evolved unique resistance capabilities to this harsh environment. Water and sediment samples were collected from the vent and from sediments located at various distances (2-20 m) away from and surrounding the chimney. Samples were screened for hypertolerant microbes that are able to withstand multiple stresses. A total of 46 isolates were selected for exposure to a number of perturbations, such as heat shock, desiccation, H(2)O(2), and ultraviolet (UV) and gamma-irradiation. The survival of Psychrobacter sp. L0S3S-03b following exposure to >1,000 J/m(2) UV(254) radiation was particularly intriguing amid a background of varying levels of resistance. Vegetative cells of this non-spore-forming microbe not only survived all of the treatments, but also exhibited a 90% lethal dose of 30 s when exposed to simulated martian UV radiation and a 100% lethal dose of 2 min when exposed to full spectrum UV, which is comparable to findings for bacterial endospores.

Monitoring of Solar‐UV Exposure among Schoolchildren in Five Japanese Cities Using Spore Dosimeter and UV‐coloring Labels

PubMed Central

Ono, Masashi; Watanabe, Shaw

1998-01-01

To monitor personal exposure to biologically effective solar‐UV radiation, Bacillus subtilis spores on a membrane filter and UV‐coloring labels were incorporated into a monitoring badge. The samples were covered with one of three types of filter sheet, dependent on the season, to reduce the amounts of exposure to measurable levels. Five fifth‐ or sixth‐grade classes of primary schools, each consisting of 30–40 children, were chosen in northern (Sapporo), central (Tsukuba and Tokyo), and southern (Miyazaki and Naha) cities in Japan. In all four seasons, each child wore a badge on an upper arm for the entire waking hours, changing it daily, for a week. Upon collection of the badges, the survival of spores and the extent of coloration of the label were determined. The results were used to estimate the amount of daily exposure to biologically effective UV radiation, expressed as the value of spore inactivation dose. Unexpectedly, the average amounts of exposure were not directly correlated with the outdoor UV irradiance: in the two southern cities, despite high outdoor irradiance from spring to autumn, the average amounts of exposure were less than 3.1% of the average irradiance. Highly concentrated exposures occurred in two central cities on three days when extensive outdoor exercise took place. These results contradict the simple notion that childrens' exposure is in proportion to the outdoor UV irradiance, and support the view that the extent of solar‐UV exposure is primarily determined by life‐style rather than living location. PMID:9600116

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

PubMed

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

2011-02-01

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

Photoprotective effects of methoxycinnamidopropyl polysilsesquioxane.

PubMed

Choi, Dae-Kyoung; Jung, Taek Kyu; Lim, Tae-Yeon; Kim, Tae-Heung; Kim, Young Baek; Lee, Jeung-Hoon; Yoon, Kyung-Sup; Yoon, Tae-Jin

2011-01-01

A new sunscreen ingredient, methoxycinnamidopropyl polysilsesquioxane (MCP-PSQ), which contains an UV-absorbing p-methoxycinnamoyl group, has been developed synthetically and evaluated using in vitro and in vivo approaches. Previous studies revealed that MCP-PSQ has a raising or boosting effect on the sun protection factor (SPF) of other sunscreen agents. In this study, we demonstrated that MCP-PSQ, an organic/inorganic hybrid compound, has photoprotective effects for human fibroblasts, and for hairless mouse and human skin. MCP-PSQ increases cell viability and suppresses the expression of p53 protein in fibroblasts after UV exposure. In addition, the numbers of sunburn cells and mast cells are reduced by topical application of MCP-PSQ on hairless mouse skin after UV irradiation. A 10% MCP-PSQ cream has higher and similar effects on SPF values for human skin compared to 5% titanium dioxide (TiO(2)) and 5% ethylhexyl methoxycinnamate (EHMC), respectively. The SPF value obtained using the MCP-PSQ cream did not drop after UV irradiation of the cream itself. However, higher dose of UV irradiation is required to guarantee the stability or photostability of the formulation. Further, there were no side effects such as erythema, edema, itch or tingling, suggesting that MCP-PSQ is a good sunscreen agent. © 2011 The Authors. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

Comparison of ultraviolet light-emitting diodes and low-pressure mercury-arc lamps for disinfection of water.

PubMed

Sholtes, Kari A; Lowe, Kincaid; Walters, Glenn W; Sobsey, Mark D; Linden, Karl G; Casanova, Lisa M

2016-09-01

Ultraviolet (UV) light-emitting diodes (LEDs) emitting at 260 nm were evaluated to determine the inactivation kinetics of bacteria, viruses, and spores compared to low-pressure (LP) UV irradiation. Test microbes were Escherichia coli B, a non-enveloped virus (MS-2), and a bacterial spore (Bacillus atrophaeus). For LP UV, 4-log10 reduction doses were: E. coli B, 6.5 mJ/cm(2); MS-2, 59.3 mJ/cm(2); and B. atrophaeus, 30.0 mJ/cm(2). For UV LEDs, the 4-log10 reduction doses were E. coli B, 6.2 mJ/cm(2); MS-2, 58 mJ/cm(2); and B. atrophaeus, 18.7 mJ/cm(2). Microbial inactivation kinetics of the two UV technologies were not significantly different for E. coli B and MS-2, but were different for B. atrophaeus spores. UV LEDs at 260 nm are at least as effective for inactivating microbes in water as conventional LP UV sources and should undergo further development in treatment systems to disinfect drinking water.

[Antiinflammatory potential of seven plant extracts in the ultraviolet erythema test. A randomized, placebo-controlled study].

PubMed

Beikert, F C; Schönfeld, B S; Frank, U; Augustin, M

2013-01-01

Phytotherapeutics are widely used in medicine. The aim of this study was the evaluation of the antiinflammatory potential of seven medical plant extracts using the ultraviolet- (UV)-erythema test. Randomized, placebo-controlled study on 40 healthy subjects. Test areas on the upper back were irradiated with the 1.5 fold UV-B minimal erythema dose (MED). Formulations of Aloe vera, Chamomilla recutita, Hamamelis virginiana, Melissa officinalis, Mentha arvensis, Melaleuca alternifolia, Coriandrum sativum as well as 1% hydrocortisone acetate and 0.1% betamethasone valerate as positive controls and unguentum leniens as vehicle control were applied under occlusion on the irradiated areas and on non-irradiated area on the contralateral side. Photometric assessment of the erythema was performed before the application of the substances (t0), at 24 h (t1) and at 48 h (t2). Aloe vera, Chamomilla recutita, Melissa officinalis, Melaleuca alternifolia and Coriandrum sativum showed an antiinflammatory effect compared to UV-control and unguentum leniens. However, the results were only statistically significant for Aloe vera. All tested plant extracts were well tolerated. Aloe vera possesses an antiinflammatory effect on UV-induced erythemas.

Xeroderma pigmentosum variant cells are less likely than normal cells to incorporate dAMP opposite photoproducts during replication of UV-irradiated plasmids

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

Wang, Y.C.; Maher, V.M.; McCormich, J.J.

1991-09-01

Xeroderma pigmentosum (XP) variant patients show the clinical characteristics of the disease, with increased frequencies of skin cancer, but their cells have a normal, or nearly normal, rate of nucleotide excision repair of UV-induced DNA damage and are only slightly more sensitive than normal cells to the cytotoxic effect of UV radiation. However, they are significantly more sensitive to its mutagenic effect. To examine the mechanisms responsible for this hypermutability, the authors transfected an XP variant cell line with a UV-irradiated (at 254 nm) shuttle vector carrying the {sup F} gene as a target for mutations, allowed replication of themore » plasmid, determined the frequency and spectrum of mutations induced, and compared the results with those obtained previously when irradiated plasmids carrying the same target gene replicated in a normal cell line. The frequency of mutants increased linearly with dose, but with a slope 5 times steeper than that seen with normal cells. Sequence analysis of the {sup F} gene showed that 52 of 53 independent mutants generated in the XP variant cells contained base substitutions, with 62 of 64 of the substitutions involving a dipyrimidine.« less

The reciprocity law concerning light dose relationships applied to BisGMA/TEGDMA photopolymers: theoretical analysis and experimental characterization.

PubMed

Wydra, James W; Cramer, Neil B; Stansbury, Jeffrey W; Bowman, Christopher N

2014-06-01

A model BisGMA/TEGDMA unfilled resin was utilized to investigate the effect of varied irradiation intensity on the photopolymerization kinetics and shrinkage stress evolution, as a means for evaluation of the reciprocity relationship. Functional group conversion was determined by FTIR spectroscopy and polymerization shrinkage stress was obtained by a tensometer. Samples were polymerized with UV light from an EXFO Acticure with 0.1wt% photoinitiator. A one-dimensional kinetic model was utilized to predict the conversion-dose relationship. As irradiation intensity increased, conversion decreased at a constant irradiation dose and the overall dose required to achieve full conversion increased. Methacrylate conversion ranged from 64±2% at 3mW/cm(2) to 78±1% at 24mW/cm(2) while the final shrinkage stress varied from 2.4±0.1MPa to 3.0±0.1MPa. The ultimate conversion and shrinkage stress levels achieved were dependent not only upon dose but also the irradiation intensity, in contrast to an idealized reciprocity relationship. A kinetic model was utilized to analyze this behavior and provide theoretical conversion profiles versus irradiation time and dose. Analysis of the experimental and modeling results demonstrated that the polymerization kinetics do not and should not be expected to follow the reciprocity law behavior. As irradiation intensity is increased, the overall dose required to achieve full conversion also increased. Further, the ultimate conversion and shrinkage stress that are achieved are not dependent only upon dose but rather upon the irradiation intensity and corresponding polymerization rate. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Irradiation of Frozen Solutions of Ferrous Sulphate as Dosimeter for Low Temperature Irradiations

NASA Astrophysics Data System (ADS)

Sánchez-Mejorada, G.; Frias, D.

2006-09-01

A theoretical model is presented for the evaluation of the energy transferred during the interaction of high energy radiation with icy bodies. Numerical simulations of the chemical reaction system reproduce the behavior of the icy systems (frozen solution of iron salts) after its interaction with the gamma radiation. Simulation experiments of extraterrestrial bodies are useful for space research, where low temperature dosimetry is necessary, especially in trips with humans or in the International Space Station (ISS) where humans are exposed to high radiation doses. The results showed that theoretical model applied for the irradiated system for different doses (from 10 to 2500Gy) and at different temperature (from 77 to 298 °K). The system under study was frozen solutions of iron salts and were analyzed (after Melting) by UV-spectroscopy. The systems were irradiates with gamma radiation. It is also shown that the response of the system is a function of the temperature and it was linear with as a function of dose.

Development of action levels for MED/MPD skin-testing units in ultraviolet phototherapy

NASA Astrophysics Data System (ADS)

O'Connor, Una M.; O'Hare, Neil J.

2003-03-01

Ultraviolet (UV) Phototherapy is commonly used for treatment of skin diseases such as psoriasis and eczema. Treatment is carried out using UV phototherapy units, exposing all or part of the body for a certain exposure time. Prior to exposure in treatment units, an unaffected area of skin may be tested using UV skin-testing units in order to determine a suitable treatment regime. The exposure time at which barely perceptible erythema has developed is known as the Minimal Erythemal Dose (MED) for UVB therapy and Minimal Phototoxic Dose (MPD) for UVA therapy. This is used to determine the starting dose in the treatment regime. The presence of 'hotspots' and 'coldspots' in UV skin-testing units can result in inaccurate determination of MED/MPD. This could give rise to severe burns during treatment, or in a sub-optimal dose regime being used. Quality assurance protocols for UV phototherapy equipment have recently been developed and these protocols have highlighted the need for action levels for skin-testing units. An action level is a reference value, which is used to determine whether the difference in irradiance output level across a UV unit is acceptable. Current methodologies for skin-testing in Ireland have been characterised and errors introduced during testing have been estimated. Action levels have been developed based on analysis of errors and requirements of skin-testing.

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

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

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

1994-06-01

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

Granzyme B mediates both direct and indirect cleavage of extracellular matrix in skin after chronic low-dose ultraviolet light irradiation.

PubMed

Parkinson, Leigh G; Toro, Ana; Zhao, Hongyan; Brown, Keddie; Tebbutt, Scott J; Granville, David J

2015-02-01

Extracellular matrix (ECM) degradation is a hallmark of many chronic inflammatory diseases that can lead to a loss of function, aging, and disease progression. Ultraviolet light (UV) irradiation from the sun is widely considered as the major cause of visible human skin aging, causing increased inflammation and enhanced ECM degradation. Granzyme B (GzmB), a serine protease that is expressed by a variety of cells, accumulates in the extracellular milieu during chronic inflammation and cleaves a number of ECM proteins. We hypothesized that GzmB contributes to ECM degradation in the skin after UV irradiation through both direct cleavage of ECM proteins and indirectly through the induction of other proteinases. Wild-type and GzmB-knockout mice were repeatedly exposed to minimal erythemal doses of solar-simulated UV irradiation for 20 weeks. GzmB expression was significantly increased in wild-type treated skin compared to nonirradiated controls, colocalizing to keratinocytes and to an increased mast cell population. GzmB deficiency significantly protected against the formation of wrinkles and the loss of dermal collagen density, which was related to the cleavage of decorin, an abundant proteoglycan involved in collagen fibrillogenesis and integrity. GzmB also cleaved fibronectin, and GzmB-mediated fibronectin fragments increased the expression of collagen-degrading matrix metalloproteinase-1 (MMP-1) in fibroblasts. Collectively, these findings indicate a significant role for GzmB in ECM degradation that may have implications in many age-related chronic inflammatory diseases. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Hydration and transparency of the rabbit cornea irradiated with UVB-doses of 0.25 J/cm(2) and 0.5 J/cm(2) compared with equivalent UVB radiation exposure reaching the human cornea from sunlight.

PubMed

Cejka, Cestmír; Ardan, Taras; Sirc, Jakub; Michálek, Jiří; Beneš, Jiří; Brůnová, Blanka; Rosina, Jozef

2011-07-01

Exposure of the cornea to UV radiation from sunlight evokes intraocular inflammation, photokeratitis. Photokeratitis is caused by UVB radiation. It is accompanied by changes of corneal hydration and light absorption. The aim of this study was to examine the effect of two UVB doses on corneal optics in rabbits and to compare these UVB doses with the equivalent exposure of UVB radiation reaching the human cornea from sunlight. Rabbit corneas were irradiated with a daily UVB dose of 0.25 J/cm(2) or 0.5 J/cm(2) for 4 days. One day after finishing the irradiations the rabbits were sacrificed and corneal light absorption measured using our spectrophotometrical method. Corneal hydration was examined using an ultrasonic Pachymeter every experimental day before the irradiation procedure and the last day before sacrificing the animals. Changes in corneal optics appeared after the repeated exposure of the cornea to a UVB dose of 0.25 J/ cm(2) and massively increased after the repeated exposure of the cornea to a UVB dose of 0.5 J/cm(2). The first significant changes in corneal hydration appeared after a single exposure of the cornea to a UVB dose of 0.25 J/cm(2). Changes in corneal hydration appeared after the exposure of the rabbit cornea to a single UVB dose equivalent to 2.6 hours of solar UVB radiation reaching the human cornea, as measured by UVB sensors embedded in the eyes of mannequin heads facing the sun on a beach at noon in July. Repeated exposure of the rabbit cornea to the same UVB dose evoked profound changes in corneal optics. Although comparison of experimental and outdoor conditions are only approximate, the results in rabbits point to the danger for the human eye from UVB radiation when short stays in sunlight are repeated for several consecutive days without UV protection.

UV-biosensor for visual indication of vitamin D synthesis

NASA Astrophysics Data System (ADS)

Orlova, T. N.; Terenetskaya, I. P.

2008-04-01

Excessive UV doses have adverse effects on human health, but proper amount of UV is beneficial for people and is essential in the natural production of vitamin D# in skin. Most of broadband UV-radiometers that have an output in sunburn units are incapable to record correctly the vitamin D synthetic capacity of sunlight because of the difference between the CIE erythema and 'Vitamin D synthesis' action spectra. The liquid-crystalline UV sensor based on provitamin D photoconversions has been developed for direct observation of vitamin D synthesis under UV irradiation. UV-induced transformation of provitamin D in cholesteric liquid-crystalline matrix is accompanied by the change of cholesteric pitch value in the LC cell. The developed UV biosensor makes possible both instrumental and visual monitoring of the vitamin D synthetic capacity of sunlight and/or artificial UV source.

Direct synthesis of graphitic mesoporous carbon from green phenolic resins exposed to subsequent UV and IR laser irradiations

PubMed Central

Sopronyi, Mihai; Sima, Felix; Vaulot, Cyril; Delmotte, Luc; Bahouka, Armel; Matei Ghimbeu, Camelia

2016-01-01

The design of mesoporous carbon materials with controlled textural and structural features by rapid, cost-effective and eco-friendly means is highly demanded for many fields of applications. We report herein on the fast and tailored synthesis of mesoporous carbon by UV and IR laser assisted irradiations of a solution consisting of green phenolic resins and surfactant agent. By tailoring the UV laser parameters such as energy, pulse repetition rate or exposure time carbon materials with different pore size, architecture and wall thickness were obtained. By increasing irradiation dose, the mesopore size diminishes in the favor of wall thickness while the morphology shifts from worm-like to an ordered hexagonal one. This was related to the intensification of phenolic resin cross-linking which induces the reduction of H-bonding with the template as highlighted by 13C and 1H NMR. In addition, mesoporous carbon with graphitic structure was obtained by IR laser irradiation at room temperature and in very short time periods compared to the classical long thermal treatment at very high temperatures. Therefore, the carbon texture and structure can be tuned only by playing with laser parameters, without extra chemicals, as usually required. PMID:28000781

Evaluation of colorless polyimide film for thermal control coating applications

NASA Technical Reports Server (NTRS)

St. Clair, A. K.; Slemp, W. S.

1985-01-01

A series of essentially colorless aromatic polyimide films has been synthesized and characterized with the objective of obtaining maximum optical transparency for applications in space. Optical transparency is a requirement for high performance polymeric films used in second surface mirror coatings on thermal control systems. The intensity in color of aromatic polyimide films was lowered by reducing the electronic interaction between chromophoric centers in the polymer molecular structure and by using highly purified monomers. The resulting lightly colored to colorless polyimide films have been characterized by UV-visible and infrared spectroscopy before and after exposure to 300 equivalent solar hours UV irradiation and varying doses of 1 MeV electron irradiation. After irradiation, the films were found to be 2 to 2.5 times more transparent than commercial polyimide film of the same thickness.

Influence of UV dose on the UV/H2O2 process for the degradation of carbamazepine in wastewater.

PubMed

Somathilake, Purnima; Dominic, John Albino; Achari, Gopal; Langford, Cooper H; Tay, Joo-Hwa

2018-05-02

This study evaluates the influence of UV dose on degradation of carbamazepine (CBZ) in wastewater under UV-C (λ = 254 nm) photolysis with and without H 2 O 2 . The rate of degradation of CBZ exhibited a direct dependence on the intensity of incident UV irradiation as the rate of degradation was observed to increase linearly (R 2  = 0.98) with UV intensity between 1.67 and 8.95 × 10 17 photons/s. More than 95% of the CBZ that spiked in wastewater rapidly degraded within 4 min with a first-order rate constant of 1.2 min -1 for an optimum H 2 O 2 dose of 100 mg/L. Bench-scale continuous flow reactor experiments also showed that CBZ degraded with first-order kinetics at a rate constant of 1.02 min -1 . The kinetic parameters obtained for a continuous bench-scale reactor were in good agreement with the relationships developed through batch experiments with only a marginal deviation of ± 6.5%. The relationship between UV intensity and CBZ degradation rate obtained in this study was extrapolated to the UV disinfection unit of a wastewater treatment plant to predict possible degradation of CBZ during UV disinfection. The addition of 100 mg/L of H 2 O 2 to the secondary-treated effluent entering the UV disinfection unit is predicted to achieve over 60% degradation of CBZ.

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

NASA Astrophysics Data System (ADS)

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

2017-09-01

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

Infectivity reduction efficacy of UV irradiation and peracetic acid-UV combined treatment on MS2 bacteriophage and murine norovirus in secondary wastewater effluent.

PubMed

Weng, ShihChi; Dunkin, Nathan; Schwab, Kellogg J; McQuarrie, James; Bell, Kati; Jacangelo, Joseph G

2018-09-01

Peracetic acid (PAA) is a strong oxidant/bactericide that has been applied in various industries (e.g., food processing, pharmaceuticals, medical device sterilization, etc.) as a disinfectant. There is increasing interest in using PAA for wastewater disinfection because it does not form halogenated byproducts, and no post-treatment quenching is required. Previous studies have demonstrated good efficiency in controlling bacteria in wastewater, but limited information is available for viruses, especially those hosted by mammals (e.g., norovirus). Therefore, a study on the infectivity reduction of murine norovirus (MNV) was undertaken to evaluate the disinfection efficacy of PAA or UV alone and in combination with UV irradiation in undisinfected secondary effluent from a municipal wastewater reclamation facility (MWW) and phosphate buffer solution (PBS) at pH 7. Experiments employing MS2 bacteriophage were also performed in parallel for comparison purposes. MS2 infectivity reduction was found to be lower than MNV infectivity reduction for each condition studied - PAA, PAA + UV, and UV disinfection. These data suggest that MS2 may not be an appropriate surrogate to accurately predict the reduction of MNV infectivity. UV irradiation, in a dose range of 5-250 mJ/cm 2 , provided linear log inactivation (-log (N/N 0 )) with a regression slope (cm 2 mJ -1 ) of 0.031-0.034 and 0.165-0.202 for MS2 and MNV, respectively. UV irradiation provided similar inactivation for MS2 and MNV in both suspensions (PBS or MWW). Low infectivity reduction of MS2 was observed when PAA was used alone at a practical dose of 1.5 mg/L and below. A greater reduction of both MNV and MS2 was observed in PAA disinfection experiments using PBS as the microbial suspension medium, than in secondary effluent. Similar results were observed in PAA + UV experiments, in which greater synergistic effects were found in PBS than in MWW. Results of OH radical formation experiments suggest the presence of radical scavengers in MWW, which resulted in less opportunity for MNV and MS2 to encounter OHradicals. This study also demonstrated that the type of water can have a substantial impact on wastewater disinfection when employing PAA or PAA + UV treatment due to the matrix effect and the presence of radical scavengers, respectively. The results from this study could be employed to aid in the conceptual design of PAA and UV disinfection facilities, especially when norovirus is the organism of concern. Copyright © 2018. Published by Elsevier Ltd.

Irradiation study of UV Silicon Photomultipliers for the Mu2e calorimeter

NASA Astrophysics Data System (ADS)

Baccaro, S.; Cemmi, A.; Cordelli, M.; Diociaiuti, E.; Donghia, R.; Ferrari, A.; Giovannella, S.; Loreti, S.; Miscetti, S.; Müller, S.; Pillon, M.; Sarra, I.

2017-02-01

The Mu2e calorimeter is composed of 1400 un-doped CsI crystals, coupled to large area UV extended Silicon Photomultipliers (SiPMs), arranged in two annular disks. This calorimeter has to provide precise information on energy, timing and position resolutions. It should also be fast enough to handle the high rate background and it must operate and survive in the high radiation environment. Simulation studies estimated that, in the highest irradiated regions, each photo-sensor will absorb a dose of 20 krad and will be exposed to a neutron fluency of 5.5×1011n1 MeV/cm2 in three years of running, with a safety factor of 3 included. At the end of 2015, we have concluded an irradiation campaign at the Frascati Neutron Generator (FNG, Frascati, Italy) measuring the response of two different 16 array models from Hamamatsu, which differ for the protection windows and a SiPM from FBK. In 2016, we have carried out two additional irradiation campaigns with neutrons and photons at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR, Dresden, Germany) and at the Calliope gamma irradiation facility at ENEA-Casaccia, respectively. A negligible increment of the leakage current and no gain change have been observed with the dose irradiation. On the other hand, at the end of the neutron irradiation, the gain does not show large changes whilst the leakage current increases by around a factor of 2000. In these conditions, the too high leakage current makes problematic to bias the SiPMs, thus requiring to cool them down to a running temperature of ~0oC.

The effect of inorganic precursors on disinfection byproduct formation during UV-chlorine/chloramine drinking water treatment.

PubMed

Lyon, Bonnie A; Dotson, Aaron D; Linden, Karl G; Weinberg, Howard S

2012-10-01

Ultraviolet (UV) disinfection is being increasingly used in drinking water treatment. It is important to understand how its application to different types of water may influence finished water quality, particularly as anthropogenic activity continues to impact the quality of source waters. The objective of this study was to evaluate the effect of inorganic precursors on the formation of regulated and unregulated disinfection byproducts (DBPs) during UV irradiation of surface waters when combined with chlorination or chloramination. Samples were collected from three drinking water utilities supplied by source waters with varying organic and inorganic precursor content. The filtered samples were treated in the laboratory with a range of UV doses delivered from low pressure (LP, UV output at 253.7 nm) and medium pressure (MP, polychromatic UV output 200-400 nm) mercury lamps followed by chlorination or chloramination, in the presence and absence of additional bromide and nitrate. The regulated trihalomethanes and haloacetic acids were not affected by UV pretreatment at disinfection doses (40-186 mJ/cm²). With higher doses (1000 mJ/cm²), trihalomethane formation was increased 30-40%. While most effects on DBPs were only observed with doses much higher than typically used for UV disinfection, there were some effects on unregulated DBPs at lower doses. In nitrate-spiked samples (1-10 mg N/L), chloropicrin formation doubled and increased three- to six-fold with 40 mJ/cm² MP UV followed by chloramination and chlorination, respectively. Bromopicrin formation was increased in samples containing bromide (0.5-1 mg/L) and nitrate (1-10 mg N/L) when pretreated with LP or MP UV (30-60% with 40 mJ/cm² LP UV and four- to ten-fold increase with 40 mJ/cm² MP UV, after subsequent chlorination). The formation of cyanogen chloride doubled and increased three-fold with MP UV doses of 186 and 1000 mJ/cm², respectively, when followed by chloramination in nitrate-spiked samples but remained below the World Health Organization guideline value of 70 μg/L in all cases. MP UV and high LP UV doses (1000 mJ/cm²) increased chloral hydrate formation after subsequent chlorination (20-40% increase for 40 mJ/cm² MP UV). These results indicate the importance of bench-testing DBP implications of UV applications in combination with post-disinfectants as part of the engineering assessment of a UV-chlorine/chloramine multi-barrier disinfection design for drinking water treatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of UV irradiation in a continuous turbulent flow UV reactor on microbiological and sensory characteristics of cow's milk.

PubMed

Rossitto, P V; Cullor, J S; Crook, J; Parko, J; Sechi, P; Cenci-Goga, B T

2012-12-01

The dairy industry under current pasteurization conditions (15 s at 72°C) and sanitary standards achieves a safe product with excellent quality. In an ever-competitive market there is still a need to improve product quality and extend shelf life of dairy products to increase competitiveness and open up new markets. In an attempt to test the effect of UV irradiation on microbiota of fluid milk, a continuous flow UV system at 254 nm was used to treat 3.5 and 2% fat milk at two UV doses (880 and 1,760 J liter(-1)). Milk was obtained from three processors, and two lots from each processor were assessed. To assess the impact on the most descriptive native microbiota in pasteurized milk after UV illumination, the product was held at two storage temperatures (4 and 7°C) and tested weekly for 5 weeks for aerobic plate counts (psychrotrophic and mesophilic bacteria), laboratory pasteurization counts, aerobic sporeformers, coliform organisms, and titratable acidity. Microbial counts for all tested microorganisms were lower in UV-treated milk when compared with control throughout storage at 4 and 7°C in both 3.5 and 2% fat milk. Sensory analysis indicated that there is a sensory defect associated with UV treatment at the wavelength used.

Dose-Response Effect of Sunlight on Vitamin D2 Production in Agaricus bisporus Mushrooms.

PubMed

Urbain, Paul; Jakobsen, Jette

2015-09-23

The dose response effect of UV-B irradiation from sunlight on vitamin D2 content of sliced Agaricus bisporus (white button mushroom) during the process of sun-drying was investigated.Real-time UV-B and UV-A data were obtained using a high-performance spectroradiometer. During the first hour of sunlight exposure, the vitamin D2 content of the mushrooms increased in a linear manner, with concentrations increasing from 0.1 μg/g up to 3.9 ± 0.8 μg/g dry weight (DW). At the subsequent two measurements one and 3 h later, respectively, a plateau was reached. Two hours of additional exposure triggered a significant decline in vitamin D2 content. After just 15 min of sun exposure and an UV-B dose of 0.13 J/cm(2), the vitamin D2 content increased significantly to 2.2 ± 0.5 μg/g DW (P < 0.0001), which is equivalent to 17.6 μg (704 IU) vitamin D2 per 100 g of fresh mushrooms and comparable to levels found in fatty fish like the Atlantic salmon.

Liquid egg white pasteurization using a centrifugal UV irradiator.

PubMed

Geveke, David J; Torres, Daniel

2013-03-01

Studies are limited on UV nonthermal pasteurization of liquid egg white (LEW). The objective of this study was to inactivate Escherichia coli using a UV irradiator that centrifugally formed a thin film of LEW on the inside of a rotating cylinder. The LEW was inoculated with E. coli K12 to approximately 8 log cfu/ml and was processed at the following conditions: UV intensity 1.5 to 9.0 mW/cm²; cylinder rotational speed 450 to 750 RPM, cylinder inclination angle 15° to 45°, and flow rate 300 to 900 ml/min, and treatment time 1.1 to 3.2s. Appropriate dilutions of the samples were pourplated with tryptic soy agar (TSA). Sublethal injury was determined using TSA+4% NaCl. The regrowth of surviving E. coli during refrigerated storage for 28 days was investigated. The electrical energy of the UV process was also determined. The results demonstrated that UV processing of LEW at a dose of 29 mJ/cm² at 10°C reduced E. coli by 5 log cfu/ml. Inactivation significantly increased with increasing UV dose and decreasing flow rate. The results at cylinder inclination angles of 30° and 45° were similar and were significantly better than those at 15°. The cylinder rotational speed had no significant effect on inactivation. The occurrence of sublethal injury was detected. Storage of UV processed LEW at 4° and 10°C for 21 days further reduced the population of E. coli to approximately 1 log cfu/ml where it remained for an additional 7 days. The UV energy applied to the LEW to obtain a 5 log reduction of E. coli was 3.9 J/ml. These results suggest that LEW may be efficiently pasteurized, albeit at low flow rates, using a nonthermal UV device that centrifugally forms a thin film. Published by Elsevier B.V.

Retrieving atmospheric transmissivity for biologically active daily dose, in various european sites

NASA Astrophysics Data System (ADS)

de La Casinière, A.; Touré, M. L.; Lenoble, J.; Cabot, T.

2003-04-01

In the frame of the European Project EDUCE, global UV irradiance spectra recorded all along the year in several European sites are stored in a common database located in Finland. From the spectra set of some of these stations, are calculated atmospheric transmissivities for daily doses of four biologically active UV radiation, namely: UV-B, erythema, DNA damage, and plant damage. A transmissivity is defined as the ratio of the ground level value of the daily dose of interest to its corresponding extra-atmospheric value. Multiple linear correlation of the various transmissivities with three predictors (daily sunshine fraction, cosine of the daily minimum SZA, and daily total ozone column) assumed to be independent variables, are done for year 2000. The coefficients obtained from year 2000 correlation in a given site are expected to retrieve, from the local predictors, the daily dose for year 2001 in the same site, the average error being lesser than 10% for monthly mean values, and lesser than 5% for three-monthly mean values, depending on the daily dose type. Comparison of yearly mean daily doses retrieved in a given site from coefficients obtained in other sites is also presented.

New apparatus with high radiation energy between 320-460 nm: physical description and dermatological applications

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

Mutzhas, M.F.; Holzle, E.; Hofmann, C.

1981-01-01

A new apparatus (UVASUN 5000) is presented with high-radiation energy between 320 to 460 nm. The measureable energy below 320 nm was shown to be many orders of magnitude too low to produce erythema. The radiator is a specially developed source for high uv-A intensity, housing a quartz bulb with a mixture of argon, mercury and metal-halides. At a skin-target distance of 0.2 m the size of the irradiated area is 0.35 x 0.35 m, and the measured mean uv-A intensity is about 1400 W. m-2 (140 mW . cm-2). The uv-A energy in the range of 320 to 400more » nm is about 84% of the total radiation energy. Effects of very high doses of uv-A on human skin were studied. Following single uv-a applications the minimal tanning dose uv-A (MTD) and the immediate pigment darkening (IPD) dose of uv-A were established. The calculated IPD threshold time was 1.8 min at 0.2 m. Repeated exposure to this uv-A delivering system yields long lasting dark brown skin pigmentation without any clinical or histological signs of sunburn (uv-B) damage, epidermal hyperplasia or thickening of the stratum corneum. The instrument was also successfully used for photo-patch testing and reproduction of skin lesions of polymorphous light eruption. Minimal therapeutic results were seen in the phototherapy of vitiligo and inflammatory acne.« less

Preliminary results on the photo-transferred thermoluminescence from Ge-doped SiO2 optical fiber

NASA Astrophysics Data System (ADS)

Zulkepely, Nurul Najua; Amin, Yusoff Mohd; Md Nor, Roslan; Bradley, D. A.; Maah, Mohd Jamil; Mat Nawi, Siti Nurasiah; Wahib, Nur Fadira

2015-12-01

A study is made of photo-transferred thermoluminescence (PTTL), the TL being induced by transferring charge carriers from deeper to more superficial traps through energetic light exposure. Potential applications include dose reassessment in radiation dosimetry and also as a useful tool for dating. With incomplete emptying of deep traps following first readout, subsequent UV exposure is shown to lead to charge transfer to more shallow traps. Using Ge-doped SiO2 optical fibers exposed to 60Co gamma rays, the PTTL from the medium has been characterized in terms of the stimulation provided by exposure to a UV lamp and duration of exposure, maximum read-out temperature and pre-gamma irradiation dose. Ge-doped SiO2 optical fibers of flat cross-sectional shape have been used in this study. The efficiency of dose reassessment was compared to that of the highly popular phosphor-based TL detector TLD-100. Results show the maximum temperature of readout to have no measurable effect on the PTTL signal. For doses from 20 to 500 cGy, the method is shown to be effective using a UV lamp of wavelength 254 nm, also being indicative of potential application for doses on either side of the range currently investigated. A study was also made of the effect of UV exposure time on PTTL, seeking to determine the greatest accessible sensitivity and lowest measurable dose.

Correlation between the structure modification and conductivity of 3 MeV Si ion-irradiated polyimide

NASA Astrophysics Data System (ADS)

Sun, Youmei; Zhu, Zhiyong; Li, Changlin

2002-05-01

The surface modification of the polyimide (PI/Kapton) films was carried out by 3 MeV Si + implantation to fluences ranging from 1×10 12 to 1.25×10 15 ions/cm 2. Fourier transform infrared (FTIR), Raman and ultraviolet/visible (UV/Vis) spectroscopes were employed to investigate the chemical degradation of function groups in the irradiated layer. FTIR results show that the absorbance of typical function group decreases exponentially as a function of fluence. The damage cross-section of typical bonds of PI was evaluated from the FTIR spectra. Raman analysis shows the absorbed dose for destruction of all function groups is above 218 MGy. The red shifting of the absorption edge from UV to visible reveals the band gap closing which results from increase of the cluster size. The production efficiency of the chromophores was discussed according to UV/Vis analysis. Irradiation dramatically enhances the electrical conductivity and the sheet resistivity in our experiment descends nearly 10 orders of magnitude compared with its intrinsic value.

Degradation mechanisms of gamma irradiated LWIR HgCdTe photovoltaic detectors

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

Sarusi, G.; Eger, D.; Zemel, A.

1990-12-01

Planar n{sup +}p Hg{sub 1{minus}x}Cd{sub x}Te (x = 0.23) photodiodes passivated with ZnS were irradiated by Co{sup 60} gamma source. A strong increase in the reverse dark current was observed for doses above 0.3 Mrad(air). A similar effect was found by exposing the photodiodes to U.V illumination from a high pressure mercury lamp. By filtering the U.V light it is shown that the degradation in the performance of the photodiodes is caused by the light or radiation absorbed in the ZnS layer above the implanted n-type region. C-V measurements of irradiated MIS devices showed a significant increase in the fastmore » surface state density. Galvanomagnetic and lifetime measurements made on irradiated p-type HgCdTe layer showed no significant changes in the bulk transport parameters. Based on these findings, a model for the degradation mechanism is proposed.« less

A new dual-collimation batch reactor for determination of ultraviolet inactivation rate constants for microorganisms in aqueous suspensions

PubMed Central

Martin, Stephen B.; Schauer, Elizabeth S.; Blum, David H.; Kremer, Paul A.; Bahnfleth, William P.; Freihaut, James D.

2017-01-01

We developed, characterized, and tested a new dual-collimation aqueous UV reactor to improve the accuracy and consistency of aqueous k-value determinations. This new system is unique because it collimates UV energy from a single lamp in two opposite directions. The design provides two distinct advantages over traditional single-collimation systems: 1) real-time UV dose (fluence) determination; and 2) simple actinometric determination of a reactor factor that relates measured irradiance levels to actual irradiance levels experienced by the microbial suspension. This reactor factor replaces three of the four typical correction factors required for single-collimation reactors. Using this dual-collimation reactor, Bacillus subtilis spores demonstrated inactivation following the classic multi-hit model with k = 0.1471 cm2/mJ (with 95% confidence bounds of 0.1426 to 0.1516). PMID:27498232

Disinfection of low quality wastewaters by ultraviolet irradiation

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

Zukovs, G.; Kollar, J.; Monteith, H.D.

1986-03-01

Pilot-scale disinfection of simulated combined sewer overflow (CSO) by ultraviolet light (UV) and by high-rate chlorination were compared. Disinfection efficiency was evaluated over a range of dosages and contact times for fecal coliforms, enterococci, P. Aeruginosa, and Salmonella spp. Fecal coliform were reduced 3.0 to 3.2 logs at a UV dose of approximately 350,000..mu.. W s/cm/sup 2/. High-rate chlorination, at a contact time of 2.0 minutes and total residual chlorine concentration of approximately 25 mg/L (as Cl/sub 2/), reduced fecal coliforms by 4.0 logs. Pathogens were reduced to detection limits by both processes. Neither photoreactivation nor regrowth occurred int hemore » disinfected effluents. The estimated capital costs of CSO disinfection by UV irradiation were consistently higher than for chlorination/dechlorination; operation and maintenance costs were similar. 19 references.« less

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

PubMed

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

2012-06-01

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

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

NASA Astrophysics Data System (ADS)

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

2008-12-01

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

Biological UV dosimeters in simulated space irradiation conditions

NASA Astrophysics Data System (ADS)

Rontó, G.; Bérces, A.; Fekete, A.; Kovács, G.; Lammer, H.

For the measurement of the harmful biological effect of solar UV radiation bacteriophage T7 and polycrystalline uracil dosimeters were used. For terrestrial dosimetric purposes bacteriophage T7 has been applied in solution, while uracil in the form of thin layers. For space irradiation dosimetry the uracil, phage T7-DNA and bacteriophage T7 thin layer samples were prepared in vacuum tightly closed sandwich forms covered either by calciumfluoride or quartz windows. The experimental conditions tested correspond to the conditions planned in the EXPOSE facility: the samples were surrounded by nitrogen atmosphere at various humidities, their vacuum stability was tested in the vacuum chamber of the Institute of Space Research,, Graz. All kinds of the thin film samples have been stored in an atmosphere containing Nitrogen and Hidrogen, in quality control no change in the structure of them has been found. To attenuate the high extraterrestrial irradiance neutral filters of 0.5 and 1.0 optical densities have been tested. Irradiation of the samples has been performed with various UV sources: solar simulator, low pressure Mercury lamp, Deuterium lamp. Dose-effect functions have been determined using for the evaluation spectrophotometry in the characteristic UV range, HPLC of photoproducts, PCR of two different primer sequences of phage T7-DNA. Photoproduct formation kinetics was followed by the saturation level of uracil thin layer. Attenuation ability of the neutral filters was controlled with low pressure Mercury lamp by the exposure necessary for saturation of uracil dosimeters. A three and tenfold increase in the exposure was found respectively, while the influence of spectral composition of the irradiation source was tested using Deuterium lamp supplied with Ca F2 and quartz filters respectively. A doubling of the irradiance was necessary for the saturation of uracil with quartz filter.

Space environmental effects on polymeric materials

NASA Technical Reports Server (NTRS)

Kiefer, Richard L.; Orwoll, Robert A.

1987-01-01

Polymeric materials that may be exposed on spacecraft to the hostile environment beyond Earth's atmosphere were subjected to atomic oxygen, electron bombardment, and ultraviolet radiation in terrestrial experiments. Evidence is presented for the utility of an inexpensive asher for determining the relative susceptibility of organic polymers to atomic oxygen. Kapton, Ultem, P1700 polysulfone, and m-CBB/BIS-A (a specially formulated polymer prepared at NASA Langley) all eroded at high rates, just as was observed in shuttle experiments. Films of Ultem, P1700 polysulfone, and m-CBB/BIS-A were irradiated with 85 keV electrons. The UV/VIS absorbance of Ultem was found to decay with time after irradiation, indicating free radical decay. The tensile properties of Ultem began to change only after it had been exposed to 100 Mrads. The effects of dose rate, temperature, and simultaneous vs. sequential electron and UV irradiation were also studied.

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

PubMed

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

2017-05-01

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

X-ray irradiation of yeast cells

NASA Astrophysics Data System (ADS)

Masini, Alessandra; Batani, Dimitri; Previdi, Fabio; Conti, Aldo; Pisani, Francesca; Botto, Cesare; Bortolotto, Fulvia; Torsiello, Flavia; Turcu, I. C. Edmond; Allott, Ric M.; Lisi, Nicola; Milani, Marziale; Costato, Michele; Pozzi, Achille; Koenig, Michel

1997-10-01

Saccharomyces Cerevisiae yeast cells were irradiated using the soft X-ray laser-plasma source at Rutherford Laboratory. The aim was to produce a selective damage of enzyme metabolic activity at the wall and membrane level (responsible for fermentation) without interfering with respiration (taking place in mitochondria) and with nuclear and DNA activity. The source was calibrated by PIN diodes and X-ray spectrometers. Teflon stripes were chosen as targets for the UV laser, emitting X-rays at about 0.9 keV, characterized by a very large decay exponent in biological matter. X-ray doses to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. After irradiation, the selective damage to metabolic activity at the membrane level was measured by monitoring CO2 production with pressure silicon detectors. Preliminary results gave evidence of pressure reduction for irradiated samples and non-linear response to doses. Also metabolic oscillations were evidenced in cell suspensions and it was shown that X-ray irradiation changed the oscillation frequency.

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.

Quantitative inactivation-mechanisms of P. digitatum and A. niger spores based on atomic oxygen dose

NASA Astrophysics Data System (ADS)

Ito, Masafumi; Hashizume, Hiroshi; Ohta, Takayuki; Hori, Masaru

2014-10-01

We have investigated inactivation mechanisms of Penicillium digitatum and Asperguills niger spores using atmospheric-pressure radical source quantitatively. The radical source was specially developed for supplying only neutral radicals without charged species and UV-light emissions. Reactive oxygen radical densities such as grand-state oxygen atoms, excited-state oxygen molecules and ozone were measured using VUV and UV absorption spectroscopies. The measurements and the treatments of spores were carried out in an Ar-purged chamber for eliminating the influences of OH, NOx and so on. The results revealed that the inactivation of spores can be explained by atomic-oxygen dose under the conditions employing neutral ROS irradiations. On the basis of the dose, we have observed the changes of intracellular organelles and membrane functions using TEM, SEM and confocal- laser fluorescent microscopy. From these results, we discuss the detail inactivation-mechanisms quantitatively based on atomic-oxygen dose.

Potential link between fruit yield, quality parameters and phytohormonal changes in preharvest UV-C treated strawberry.

PubMed

Xu, Yanqun; Charles, Marie Thérèse; Luo, Zisheng; Roussel, Dominique; Rolland, Daniel

2017-07-01

Preharvest ultraviolet-C (UV-C) treatment of strawberry is a very new approach, and little information is available on the effect of this treatment on plant growth regulators. In this study, the effect of preharvest UV-C irradiations at three different doses on strawberry yield, fruit quality parameters and endogenous phytohormones was investigated simultaneously. The overall marketable yield of strawberry was not affected by the preharvest UV-C treatments, although more aborted and misshapen fruits were found in UV-C treated groups than in the untreated control. The fruits in the high dose group were firmer and had approximately 20% higher sucrose content and 15% higher ascorbic acid content than the control, while fruits from the middle and low dose groups showed no significant changes in these parameters. The lower abscisic acid (ABA) content found in the fruits in the high UV-C group may be associated with those quality changes. The citric acid content decreased only in the low dose group (reduction of 5.8%), with a concomitant 37% reduction in jasmonic acid (JA) content, compared to the control. The antioxidant status of fruits that received preharvest UV-C treatment was considered enhanced based on their oxygen radical absorbance capacity (ORAC) and malondialdehyde (MDA) content. In terms of aroma, three volatile alcohols differed significantly among the various treatments with obvious activation of alcohol acyltransferase (AAT) activity. The observed synchronous influence on physiological indexes and related phytohormones suggests that preharvest UV-C might affect fruit quality via the action of plant hormones. Crown Copyright © 2017. Published by Elsevier Masson SAS. All rights reserved.

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

PubMed

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

2013-04-01

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

Effect of UV irradiation on the shear bond strength of titanium with segmented polyurethane through gamma-mercapto propyl trimethoxysilane.

PubMed

Sakamoto, Harumi; Hirohashi, Yohei; Doi, Hisashi; Tsutsumi, Yusuke; Suzuki, Yoshiaki; Noda, Kazuhiko; Hanawa, Takao

2008-01-01

The objective of this study was to investigate the effect of UV irradiation on shear bond strength between a titanium (Ti) and a segmented polyurethane (SPU) composite through gamma-mercapto propyl trimethoxysilane (gamma-MPS). To this end, the shear bond strength of Ti/SPU interface of Ti-SPU composite under varying conditions of ultraviolet ray (UV) irradiation was evaluated by a shear bond test. The glass transition temperatures of SPU with and without UV irradiation were also determined using differential scanning calorimetry. It was found that the shear bond strength of Ti/SPU interface increased with UV irradiation. However, excessive UV irradiation decreased the shear bond strength of Ti/SPU interface. Glass transition temperature was found to increase during 40-60 seconds of UV irradiation. In terms of durability after immersion in water at 37 degrees C for 30 days, shear bond strength was found to improve with UV irradiation. In conclusion, UV irradiation to a Ti-SPU composite was clearly one of the means to improve the shear bond strength of Ti/SPU interface.

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.

Study of variations in structural, optical parameters and bulk etch rate of CR-39 polymer due to electron irradiation

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

Sahoo, G. S.; Joshi, D. S.; Tripathy, S. P., E-mail: sam.tripathy@gmail.com, E-mail: tripathy@barc.gov.in

2016-07-14

In this work, electron induced modifications on the bulk etch rate, structural and optical parameters of CR-39 polymer were studied using gravimetric, FTIR (Fourier Transform Infrared) and UV–vis (Ultraviolet–Visible) techniques, respectively. CR-39 samples were irradiated with 10 MeV electron beam for different durations to have the absorbed doses of 1, 10, 550, 5500, 16 500, and 55 000 kGy. From the FTIR analysis, the peak intensities at different bands were found to be changing with electron dose. A few peaks were observed to shift at high electron doses. From the UV-vis analysis, the optical band gaps for both direct and indirect transitions weremore » found to be decreasing with the increase in electron dose whereas the opacity, number of carbon atoms in conjugation length, and the number of carbon atoms per cluster were found to be increasing. The bulk etch rate was observed to be increasing with the electron dose. The primary objective of this investigation was to study the response of CR-39 to high electron doses and to determine a suitable pre-irradiation condition. The results indicated that, the CR-39 pre-irradiated with electrons can have better sensitivity and thus can be potentially applied for neutron dosimetry.« less

Recolonization by heterotrophic bacteria after UV irradiation or ozonation of seawater; a simulation of ballast water treatment.

PubMed

Hess-Erga, Ole-Kristian; Blomvågnes-Bakke, Bente; Vadstein, Olav

2010-10-01

Transport of ballast water with ships represents a risk for introduction of foreign species. If ballast water is treated during uptake, there will be a recolonization of the ballast water by heterotrophic bacteria during transport. We investigated survival and succession of heterotrophic bacteria after disinfection of seawater in the laboratory, representing a model system of ballast water treatment and transport. The seawater was exposed to ultraviolet (UV) irradiation, ozone (2 doses) or no treatment, incubated for 16 days and examined with culture-dependent and -independent methods. The number of colony-forming units (CFU) was reduced below the detection level after disinfection with UV and high ozone dose (700 mV), and 1% of the initial level for the low ozone dose (400 mV). After less than 3 days, the CFU was back or above the starting point for the control, UV and low ozone treatment, whereas it took slightly more than 6 days for the high ozone treatment. Disinfection increased substrate availability and reduced cell densities. Lack of competition and predation induced the recolonization by opportunistic bacteria (r-strategists), with significant increase in bacterial numbers and a low diversity (based on DGGE band pattern). All cultures stabilized after the initial recolonization phase (except Oz700) where competition due to crowding and nutrient limitation favoured bacteria with high substrate affinity (K-strategists), resulting in higher species richness and diversity (based on DGGE band pattern). The bacterial community was significantly altered qualitatively and quantitatively and may have a higher potential as invaders in the recipient depending on disinfection method and the time of release. These results have implications for the treatment strategy used for ballast water. Copyright © 2010 Elsevier Ltd. All rights reserved.

Topical grape seed proanthocyandin extract reduces sunburn cells and mutant p53 positive epidermal cell formation, and prevents depletion of Langerhans cells in an acute sunburn model.

PubMed

Yuan, Xiao-Ying; Liu, Wei; Hao, Jian-Chun; Gu, Wei-Jie; Zhao, Yan-Shuang

2012-01-01

The purpose of this study was to investigate whether grape seed proanthocyanidin extract (GSPE) can provide photoprotection against ultraviolet (UV) irradiation. Study has shown that GSPE is a natural oxidant, and is used in many fields such as ischemia-reperfusion injury, chronic pancreatitis, and even cancer. However, the effect of GSPE on UV irradiation is as yet unknown. Cutaneous areas on the backs of normal volunteers were untreated or treated with GSPE solutions or vehicles 30 min before exposure to two minimal erythema doses (MED) of solar simulated radiation. Cutaneous areas at different sites were examined histologically for the number of sunburn cells, or immunohistochemically for Langerhans cells and mutant p53 epidermal cells. On histological and immunohistochemical examination, skin treated with GSPE before UV radiation showed fewer sunburn cells and mutant p53-positive epidermal cells and more Langerhans cells compared with skin treated with 2-MED UV radiation only (p<0.001, p<0.001, and p<0.01, respectively). GSPE may be a possible preventive agent for photoprotection.

Optical study of gamma irradiated sodium metaphosphate glasses containing divalent metal oxide MO (ZnO or CdO)

NASA Astrophysics Data System (ADS)

Nabhan, E.; Abd-Allah, W. M.; Ezz-El-Din, F. M.

Sodium metaphosphate glasses containing divalent metal oxide, ZnO or CdO with composition 50 P2O5 - (50 - x) Na2O - x MO (ZnO, or CdO) where x = 0, 10, 20 (mol%) were prepared by conventional melt method. UV/visible spectroscopy and FTIR spectroscopy are measured before and after exposing to successive gamma irradiation doses (5-80 kGy). The optical absorption spectra results of the samples before irradiation reveal a strong UV absorption band at (∼230 nm) which is related to unavoided iron impurities. The effects of gamma irradiation on the optical spectral properties of the various glasses have been compared. From the optical absorption spectral data, the optical band gap is evaluated. The main structural groups and the influence of both divalent metal oxide and gamma irradiation effect on the structural vibrational groups are realized through IR spectroscopy. The FTIR spectra of γ-irradiated samples are characterized by the stability of the number and position for the main characteristic band of phosphate groups. To better understood the structural changes during γ-irradiation, a deconvolution of FTIR spectra in the range 650-1450 cm-1 is made. The FTIR deconvolution results found evidence that, the changes occurring after gamma irradiation have been related to irradiation induced structural defects and compositional changes.

Ultraviolet-B radiation induced cross-linking improves physical properties of cold- and warm-water fish gelatin gels and films.

PubMed

Otoni, Caio G; Avena-Bustillos, Roberto J; Chiou, Bor-Sen; Bilbao-Sainz, Cristina; Bechtel, Peter J; McHugh, Tara H

2012-09-01

Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm(2). Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rheological properties of the solutions as well as the tensile and water vapor barrier properties of the films were characterized. SDS-PAGE and refractive index results indicated cross-linking of gelatin chains after exposure to radiation. Interestingly, UV-B treated samples displayed higher gel strengths, with cold- and warm-water fish gelatin having gel strength increases from 1.39 to 2.11 N and from 7.15 to 8.34 N, respectively. In addition, both gelatin samples exhibited an increase in viscosity for higher UV doses. For gelatin films, the cold-water fish gelatin samples made from irradiated granules showed greater tensile strength. In comparison, the warm-water gelatin films made from irradiated granules had lower tensile strength, but better water vapor barrier properties. This might be due to the UV induced cross-linking in warm-water gelatin that disrupted helical structures. Journal of Food Science copy; 2012 Institute of Food Technologists® No claim to original US government works.

Individual variations in the correlation between erythemal threshold, UV-induced DNA damage and sun-burn cell formation.

PubMed

Heenen, M; Giacomoni, P U; Golstein, P

2001-10-01

A linear correlation between erythema intensity and DNA damage upon exposure to UV has not been firmly established. Many of the deleterious effects of UV exposure do occur after exposure to suberythemal doses. After DNA damage, cells undergo DNA repair. It is commonly accepted that when the burden of damage is beyond the repair capacities, the cell undergoes programmed cell death or apoptosis. The aim of this study is to quantify the amount of UV-induced DNA damage (estimated via the measurement of DNA repair or unscheduled DNA synthesis or UDS) and cellular damage (estimated via the determination of the density of sunburn cells or SBC). If DNA damage and erythema are correlated, similar intensity of UDS and similar density of SBC should be found in volunteers irradiated with a UV dose equal to two minimal erythema doses (MED). Our results show that in 15 different individuals the same relative dose (2 MEDs) provokes UDS values, which vary within a factor of 4. An even larger variability affects SBC counts after the same relative dose. When DNA damage or SBC are plotted versus the absolute dose (i.e. the dose expressed in J/m(2)), there is a rough correlation (with several exceptions) between dose and extent of UDS and SBC counts. It seems possible to divide the volunteers into two subpopulations with different susceptibilities to UV damage. It is well known that UDS and SBC measurements are often affected by large experimental indeterminacy, yet, the analysis of our results makes it plausible to suggest that for the triggering of erythema, a common threshold value for DNA damage or for SBC count are not to be found. In conclusion, the erythema response seems to be loosely correlated with DNA damage. This suggests that the protection offered by the sunscreens against DNA damage, the molecular basis of UV-induced mutagenesis, might not be related to the sun protection factor (SPF) indicated on the label of sunscreens, which is evaluated using the erythema as an endpoint.

Analysis of mutagenic DNA repair in a thermoconditional mutant of Saccharomyces cerevisiae. III. Dose-response pattern of mutation induction in UV-irradiated rev2ts cells.

PubMed

Siede, W; Eckardt, F

1986-01-01

Recent studies regarding the influence of cycloheximide on the temperature-dependent increase in survival and mutation frequencies of a thermoconditional rev2 mutant lead to the suggestion that the REV2-coded mutagenic repair function is UV-inducible. In the present study we show that stationary-phase rev2ts cells are characterized by a biphasic linear-quadratic dose-dependence of mutation induction ("mutation kinetics") of ochre alleles at 23 degrees C (permissive temperature) but linear kinetics at the restrictive temperature of 36 degrees C. Mathematical analysis using a model based on Poisson statistics and a further mathematical procedure, the calculation of "apparent survival", support the assumption that the quadratic component of the reverse mutation kinetics investigated can be attributed to a UV-inducible component of mutagenic DNA repair controlled by the REV2 gene.

Characterization of ferrous-methylthymol blue-polyvinyl alcohol gel dosimeters using nuclear magnetic resonance and optical techniques

NASA Astrophysics Data System (ADS)

Rabaeh, Khalid A.; Eyadeh, Molham M.; Hailat, Tariq F.; Aldweri, Feras M.; Alheet, Samer M.; Eid, Rania M.

2018-07-01

A new composition of Ferrous sulphate-Metheylthymol blue (MTB)-Polyvinyl alcohol (PVA) dosimeter is introduced in this work and evaluated using nuclear magnetic resonance (NMR) and absorbance spectrophotometry techniques. The Fricke-MTB-PVA dosimeters were irradiated using a medical linear accelerator in a cubic water phantom. The dose response of the dosimeters was investigated using NMR in terms of spin-spin relaxation rate (R2), and ultraviolet and visible regions (UV-Vis) spectrophotometry in terms of absorbance. The dosimeter presents a linear dose response for doses up to 20 Gy with UV-Vis and 40 Gy with NMR method. The sample with 0.1 mM MTB, 5% PVA by weight showed highest dose sensitivity for both techniques. The Fricke-MTB-PVA dosimeter developed in this work has a significant advance over the Fricke-MTB-gelatin system: the NMR sensitivity was remarkably improved; the auto-oxidation rate was seven times lower, and no significant dose rate or photon energy effects were observed.

Enhancement of Chaperone Activity of Plant-Specific Thioredoxin through γ-Ray Mediated Conformational Change.

PubMed

Lee, Seung Sik; Jung, Hyun Suk; Park, Soo-Kwon; Lee, Eun Mi; Singh, Sudhir; Lee, Yuno; Lee, Kyun Oh; Lee, Sang Yeol; Chung, Byung Yeoup

2015-11-13

AtTDX, a thioredoxin-like plant-specific protein present in Arabidopsis is a thermo-stable and multi-functional enzyme. This enzyme is known to act as a thioredoxin and as a molecular chaperone depending upon its oligomeric status. The present study examines the effects of γ-irradiation on the structural and functional changes of AtTDX. Holdase chaperone activity of AtTDX was increased and reached a maximum at 10 kGy of γ-irradiation and declined subsequently in a dose-dependent manner, together with no effect on foldase chaperone activity. However, thioredoxin activity decreased gradually with increasing irradiation. Electrophoresis and size exclusion chromatography analysis showed that AtTDX had a tendency to form high molecular weight (HMW) complexes after γ-irradiation and γ-ray-induced HMW complexes were tightly associated with a holdase chaperone activity. The hydrophobicity of AtTDX increased with an increase in irradiation dose till 20 kGy and thereafter decreased further. Analysis of the secondary structures of AtTDX using far UV-circular dichroism spectra revealed that the irradiation remarkably increased the exposure of β-sheets and random coils with a dramatic decrease in α-helices and turn elements in a dose-dependent manner. The data of the present study suggest that γ-irradiation may be a useful tool for increasing holdase chaperone activity without adversely affecting foldase chaperone activity of thioredoxin-like proteins.

Inactivation of Aspergillus flavus in drinking water after treatment with UV irradiation followed by chlorination.

PubMed

Al-Gabr, Hamid Mohammad; Zheng, Tianling; Yu, Xin

2013-10-01

The disinfection process for inactivating microorganisms at drinking water treatment plants is aimed for safety of drinking water for humans from a microorganism, such as bacteria, viruses, algae, fungi by using chlorination, ozonation, UV irradiation, etc. In the present study, a combination of two disinfectants, UV irradiation followed by chlorination, was evaluated for inactivating Aspergillus flavus under low contact time and low dosage of UV irradiation. The results indicated an inverse correlation between the inactivation of A. flavus by using UV irradiation only or chlorination alone. By using UV radiation, the 2 log10 control of A. flavus was achieved after 30 s of irradiation, while chlorination was observed to be more effective than UV, where the 2 log was achieved at chlorine concentration of 0.5, 1, 2 and 3 mg/l, in contact time of 60, 5, 1 and 1 min, respectively. However, combined use (UV irradiation followed by chlorination) was more effective than using either UV or chlorination alone; 5 s UV irradiation followed by chlorination produced 4 log10 reduction of A. flavus at chlorine concentrations of 2 and 3 mg/l under a contact time of 15 min. The results indicated that efficiency of UV irradiation improves when followed by chlorination at low concentrations. Copyright © 2013 Elsevier B.V. All rights reserved.

Role of interleukin 1 in antigen-specific T cell proliferation.

PubMed

Chu, E; Rosenwasser, L J; Dinarello, C A; Lareau, M; Geha, R S

1984-03-01

The role of interleukin 1 (IL 1) in human antigen-specific T cell proliferation was examined. Nylon wool-purified T cells proliferated in the presence of autologous monocytes (Mo.) pulsed for 18 h with tetanus toxoid (TT) antigen (Mo.TT). Irradiation of Mo.TT with ultraviolet (UV) light (72 J/m2) abolished their capacity to support T cell proliferation and drastically reduced their capacity to secrete IL 1 after stimulation with Staphylococcus albus. The defect in antigen presentation induced by UV irradiation of Mo.TT was reversed in a dose-dependent manner by the addition of two different preparations containing human interleukin 1 (IL 1). The first preparation consisted of supernatants of Mo. stimulated with Con A for 18 hr and in which Con A activity was blocked by alpha-D-methyl-mannoside (Mo.-Con A-Sup). The second preparation consisted of human IL 1 partially purified from supernatants of human peripheral blood mononuclear cells stimulated with S. albus. This IL 1 copurified with human leukocyte pyrogen (LP) and was termed IL 1/LP. Both IL 1-containing preparations enhanced the response of C57BL/6 mouse thymocytes to phytohemagglutinin. A rabbit antibody to human IL 1/LP inhibited the capacity of T cells to proliferate in response to Mo.TT and inhibited the capacity of Mo.-Con A-Sup to reconstitute the T cell response to UV-irradiated Mo.TT. IL 1/LP was not necessary for T cells to recognize the immunogenic moiety presented by Mo., because monolayers of UV-irradiated Mo.TT were equivalent to monolayers of unirradiated MO.TT in their capacity to adsorb TT-reactive T cells specifically. Furthermore, the addition of rabbit antibody to IL 1/LP did not interfere with the capacity of UV-irradiated Mo.TT to adsorb TT-reactive T cells. The results obtained in this study indicate that IL 1 is involved in optimal antigen-driven proliferation of human T lymphocytes.

[Effect of specific antibodies on active immunity development in those inoculated with an antirabies vaccine].

PubMed

Kravchenko, A T; Latypova, R G; Morpgova, V M; Movsesiants, A A

1980-11-01

The study of the effect of gamma globulin introduced in different doses (0.5 and 0.25 ml/mg) in combination with Fermi rabies vaccine (observations on humans were made) and with cerebral rabies vaccine inactivated by UV irradiation (in animal experiments) demonstrated that the injection of the higher doses of gamma globulin resulted in lower geometrical mean of antibody titers. Therefore, in combined administration of rabies vaccine and gamma globulin for postexposure rabies prevention it is advisable to reduce the dose of gamma globulin by one-half.

Andrographolide Sodium Bisulfate Prevents UV-Induced Skin Photoaging through Inhibiting Oxidative Stress and Inflammation

PubMed Central

Zhan, Janis Ya-Xian; Wang, Xiu-Fen; Liu, Yu-Hong; Zhang, Zhen-Biao; Wang, Lan; Chen, Jian-Nan; Huang, Song; Zeng, Hui-Fang; Lai, Xiao-Ping

2016-01-01

Andrographolide sodium bisulfate (ASB), a water-soluble form made from andrographolide through sulfonating reaction, is an antioxidant and anti-inflammatory drug; however, the antiphotoaging effect of ASB has still not been revealed. Oxidative stress and inflammation are known to be responsible for ultraviolet (UV) irradiation induced skin damage and consequently premature aging. In this study, we aimed at examining the effect of ASB on UV-induced skin photoaging of mice by physiological and histological analysis of skin and examination of skin antioxidant enzymes and immunity analyses. Results showed that topical administration of ASB suppressed the UV-induced skin thickness, elasticity, wrinkles, and water content, while ASB, especially at dose of 3.6 mg/mouse, increased the skin collagen content by about 53.17%, decreased the epidermal thickness by about 41.38%, and prevented the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, ASB decreased MDA level by about 40.21% and upregulated the activities of SOD and CAT and downregulated the production of IL-1β, IL-6, IL-10, and TNF-α in UV-irradiated mice. Our study confirmed the protective effect of ASB against UV-induced photoaging and initially indicated that this effect can be attributed to its antioxidant and anti-inflammatory activities in vivo, suggesting that ASB may be a potential antiphotoaging agent. PMID:26903706

Andrographolide Sodium Bisulfate Prevents UV-Induced Skin Photoaging through Inhibiting Oxidative Stress and Inflammation.

PubMed

Zhan, Janis Ya-Xian; Wang, Xiu-Fen; Liu, Yu-Hong; Zhang, Zhen-Biao; Wang, Lan; Chen, Jian-Nan; Huang, Song; Zeng, Hui-Fang; Lai, Xiao-Ping

2016-01-01

Andrographolide sodium bisulfate (ASB), a water-soluble form made from andrographolide through sulfonating reaction, is an antioxidant and anti-inflammatory drug; however, the antiphotoaging effect of ASB has still not been revealed. Oxidative stress and inflammation are known to be responsible for ultraviolet (UV) irradiation induced skin damage and consequently premature aging. In this study, we aimed at examining the effect of ASB on UV-induced skin photoaging of mice by physiological and histological analysis of skin and examination of skin antioxidant enzymes and immunity analyses. Results showed that topical administration of ASB suppressed the UV-induced skin thickness, elasticity, wrinkles, and water content, while ASB, especially at dose of 3.6 mg/mouse, increased the skin collagen content by about 53.17%, decreased the epidermal thickness by about 41.38%, and prevented the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, ASB decreased MDA level by about 40.21% and upregulated the activities of SOD and CAT and downregulated the production of IL-1β, IL-6, IL-10, and TNF-α in UV-irradiated mice. Our study confirmed the protective effect of ASB against UV-induced photoaging and initially indicated that this effect can be attributed to its antioxidant and anti-inflammatory activities in vivo, suggesting that ASB may be a potential antiphotoaging agent.

UV irradiation improves the bond strength of resin cement to fiber posts.

PubMed

Zhong, Bo; Zhang, Yong; Zhou, Jianfeng; Chen, Li; Li, Deli; Tan, Jianguo

2011-01-01

The purpose is to evaluate the effect of UV irradiation on the bond strength between epoxy-based glass fiber posts and resin cement. Twelve epoxy-based glass fiber posts were randomly divided into three groups. Group 1 (Cont.): No surface treatment. Group 2 (Low-UV): UV irradiation was conducted from a distance of 10 cm for 10 min. Group 3 (High-UV): UV irradiation was conducted from a distance of 1 cm for 3 min. A resin cement (CLEARFIL SA LUTING) was used for the post cementation to form resin slabs which contained fiber posts in the center. Microtensile bond strengths were tested and the mean bond strengths (MPa) were 18.81 for Cont. group, 23.65 for Low-UV group, 34.75 for High-UV group. UV irradiation had a significant effect on the bond strength (p<0.05). UV irradiation demonstrates its capability to improve the bond strength between epoxy-based glass fiber posts and resin cement.

Changes in photoinduced cutaneous erythema with topical application of a combination of vitamins C and E before and after UV exposure.

PubMed

Aguilera, José; de Gálvez, María Victoria; Sánchez, Cristina; Herrera-Ceballos, Enrique

2012-06-01

Ultraviolet radiation is harmful for human skin, and photodamaging pathologies such as actinic erythema, are formerly described as a consequence of UV direct effect on DNA and indirectly by local immune reactions. However, the degree of participation of oxidative stress in actinic erythema and the role of antioxidants in photoprotection are still not fully understood. To evaluate the possible palliative role of a combination of the antioxidants vitamins C and E in human cutaneous erythema when applied topically before and after UV exposure. The study included 20 volunteers of phototypes II, II-III and III with no solar exposure for two months prior to the study. The volunteers were submitted to a phototest consisting on the analysis of the minimal erythemal dose (MED) under different treatments: 1. Untreated irradiated skin; 2. Irradiated skin previously treated with vehicle; 3. Irradiated skin previously treated with a combination of vitamins (2.5% vit E-5% vit C); and 4. Skin treated with the antioxidant combination after irradiation. Cutaneous erythema was evaluated 24h after exposure and the MED was calculated for each treatment. The application of vehicle did not significantly affect the MED compared to untreated irradiated skin. Application of the antioxidant combination, prior to irradiation, increased the MED in all phototypes compared with untreated irradiated skin with an average increase of 36.9%. Antioxidants applied after exposure promoted an average increase of the MED by 19.8%. Combination of topical antioxidants (vitamins C and E) shows photoprotection activity against erythema, mainly owing to their high absorption properties. Moreover, their antioxidant activity could be considered as additive, and independent of their optical properties. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Radiation resistance of a gamma-ray irradiated nonlinear optic chromophore

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Taylor, Edward W.

2009-11-01

The radiation resistance of organic electro-optic and optoelectronic materials for space applications is receiving increased attention. An earlier investigation reported that guest-host poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- Vπ) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. To provide further evidences to the observed radiation stability, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data.

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 ...

Use of low-dose UV-C irradiation to control powdery mildew caused by Podosphaera aphanis on strawberry plants

USDA-ARS?s Scientific Manuscript database

Powdery mildew of strawberry plants, caused by Podoshaera aphanis, can cause severe losses by reducing fruit yield, quality and predisposing fruit to other diseases. Fungicides have been routinely used to control this disease. However, limitations mainly related to their effectiveness, re-entry pe...

Effect of gamma radiation on sugars and vitamin C: Radiolytic pathways.

PubMed

Ramírez-Cahero, Hiram F; Valdivia-López, Ma Angeles

2018-04-15

The radiolytic decomposition of glucose, fructose, sucrose, ascorbic acid (H 2 A) and dehydroascorbic acid (DHAA), induced by ionizing radiation, was investigated. Aqueous solutions of these compounds were gamma-irradiated at doses of 0.5, 0.7 and 1 kGy, with a dose rate of 0.04 kGy/min, in the presence of air, followed by HPLC, HPLC-MS, EPR, and UV-VIS spectroscopy analysis of the resulting mixtures. Carboxylic acids, 2-furaldehyde, 5-hydroxymethyl-2-furaldehyde, furfuryl alcohol, 2-furoic acid and 2(5H)-furanone were identified in solutions of sugars and vitamin C, by comparing with standards. EPR studies exhibited a higher amount of free radicals for fructose than the other sugars, and more for DHAA than H 2 A. Additionally, spectroscopic determinations showed a typical UV-VIS absorption for furans during the storage of irradiated solutions. Formation and decomposition routes for furanoids and aliphatic carboxylic acids, and mechanistic pathways for the radiolytic induced rupture of glucose, fructose, sucrose and vitamin C have been proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

UV-C irradiation delays mitotic progression by recruiting Mps1 to kinetochores.

PubMed

Zhang, Xiaojuan; Ling, Youguo; Wang, Wenjun; Zhang, Yanhong; Ma, Qingjun; Tan, Pingping; Song, Ting; Wei, Congwen; Li, Ping; Liu, Xuedong; Ma, Runlin Z; Zhong, Hui; Cao, Cheng; Xu, Quanbin

2013-04-15

The effect of UV irradiation on replicating cells during interphase has been studied extensively. However, how the mitotic cell responds to UV irradiation is less well defined. Herein, we found that UV-C irradiation (254 nm) increases recruitment of the spindle checkpoint proteins Mps1 and Mad2 to the kinetochore during metaphase, suggesting that the spindle assembly checkpoint (SAC) is reactivated. In accordance with this, cells exposed to UV-C showed delayed mitotic progression, characterized by a prolonged chromosomal alignment during metaphase. UV-C irradiation also induced the DNA damage response and caused a significant accumulation of γ-H2AX on mitotic chromosomes. Unexpectedly, the mitotic delay upon UV-C irradiation is not due to the DNA damage response but to the relocation of Mps1 to the kinetochore. Further, we found that UV-C irradiation activates Aurora B kinase. Importantly, the kinase activity of Aurora B is indispensable for full recruitment of Mps1 to the kinetochore during both prometaphase and metaphase. Taking these findings together, we propose that UV irradiation delays mitotic progression by evoking the Aurora B-Mps1 signaling cascade, which exerts its role through promoting the association of Mps1 with the kinetochore in metaphase.

High dose gamma ray exposure effect on the properties of CdSe nanowires

NASA Astrophysics Data System (ADS)

Narula, Chetna; Chauhan, R. P.

2018-03-01

We report high dose gamma-ray (γ-ray) induced modifications incurred by polycrystalline cadmium selenide (CdSe) nanowires of 80 nm diameter. The nanowires have been synthesized using polycarbonate template assisted electro-deposition technique. The samples were irradiated with 60Co γ-radiation at a dose rate of 4.533 kGy/h for different time intervals with doses varying from 0 to 400 kGy. The effects of γ rays on the structural, morphological, optical and electrical properties of nanowires are discussed. XRD patterns of as-synthesized and gamma irradiated CdSe nanowires did not show any phase transformations but the variation in relative intensity was observed. The crystallite size evaluated using Scherrer's formula was found to vary. The optical parameters were obtained using UV-vis spectrometer measurements of absorption. Band gap was found to decrease with γ irradiation up to a dose of 300 kGy after which it was seen to increase. Refractive index and optical dielectric constants were also evaluated. Subjection of γ-radiation also brings about key changes in the electrical properties of CdSe nanowires. The attained data shows that the electrical conductivity varies with absorbed dose. The variations in the properties of CdSe nanowires can be considered as a consequence of ionization process, defect production and its annihilation.

Distribution of Facial Exposure to Non-melanoma Biologically Effective UV Irradiance Changes by Rotation Angles.

PubMed

Wang, Fang; Yu, Jia Ming; Yang, De Qi; Gao, Qian; Hua, Hui; Liu, Yang

2017-02-01

To show the distribution of facial exposure to non-melanoma biologically effective UV irradiance changes by rotation angles. This study selected the cheek, nose, and forehead as representative facial sites for UV irradiance measurements, which were performed using a rotating manikin and a spectroradiometer. The measured UV irradiance was weighted using action spectra to calculate the biologically effective UV irradiances that cause non-melanoma (UVBEnon-mel) skin cancer. The biologically effective UV radiant exposure (HBEnon-mel) was calculated by summing the UVBEnon-mel data collected over the exposure period. This study revealed the following: (1) the maximum cheek, nose and forehead exposure UVA and UVB irradiance times and solar elevation angles (SEA) differed from those of the ambient UV irradiance and were influenced by the rotation angles; (2) the UV irradiance exposure increased in the following order: cheek < nose < forehead; (3) the distribution of UVBEnon-mel irradiance differed from that of unweighted UV radiation (UVR) and was influenced by the rotation angles and exposure times; and (4) the maximum percentage decreases in the UVBEnon-mel radiant exposure for the cheek, nose and forehead from 0°to 180°were 48.41%, 69.48% and 71.71%, respectively. Rotation angles relative to the sun influence the face's exposure to non-melanoma biologically effective UV. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

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 effects of gamma-ray irradiation on organic materials of different conjugation lengths

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Taylor, Edward W.

2009-08-01

The radiation resistance of organic electro-optic and optoelectronic materials of different conjugation lengths for space applications is receiving increased attention. Earlier investigation reported that guest-host (G-H) poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- Vπ) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. In this work, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data. A comparison with an in situ proton irradiated DRI/PMMA material is also presented.

Influence of thermally induced structural and morphological changes, and UV irradiation on photoluminescence and optical absorption behavior of CdS nanoparticles

NASA Astrophysics Data System (ADS)

Osman, M. A.; El-Said, Waleed A.; Othman, A. A.; Abd-Elrahim, A. G.

2016-04-01

Polycrystalline cubic CdS nanoparticles (NPs) with a crystallite size ({{D}\\text{Sch}} ) ~3 nm were synthesized by chemical precipitation method at room temperature. Thermal induced structural and morphological changes have been investigated using x-ray diffraction, high-resolution transmission electron microscope, x-ray fluorescence, Fourier transform infrared and Raman spectroscopy. The influence of these changes on optical absorption and photoluminescence (PL) characteristics have been studied. It was found that increasing annealing temperature (T a), results in structural phase transitions at 300 and 700 °C, increasing {{D}\\text{Sch}} and red shift of the optical band gap (E\\text{g}\\text{opt} ) due to the improvement in crystallinity. The photoluminescence emission spectrum of nonstoichiometric CdS (Cd-rich) nanopowder reveals emission bands at 365, 397, and 434 nm. Furthermore, PL spectrum of colloidal solution exhibits additional green and red emission bands at 535, 570 and 622 nm. To explain the mechanism of PL emission in CdS NPs, trapping and radiative recombination levels have been identified and the corresponding energy band diagrams are suggested. Annealing process results in an overall enhancement in PL intensity due to the improvement in crystallinity associated with the reduction of nonradiative surface state defects. Irradiation of CdS NPs colloidal solution at UV irradiation dose  <13 J cm-2 leads to the enhancement of PL quantum efficiency and blue shift of E\\text{g}\\text{opt} (i.e. photo-brightening) due to the decrease in the particle size deduced from Brus equation ≤ft({{D}\\text{Brus}}\\right) , This behavior is due to UV irradiation effects such as photopolymerization, the formation of CdSO4 passivation layers due to photooxidation and the reduction in {{D}\\text{Brus}} by photocorrosion process. At UV irradiation dose  <13 J cm-2, PL emission intensity continuously enhances without any change in both E\\text{g}\\text{opt} and {{D}\\text{Brus}} . This behavior is discussed in terms of electron filling model. Boltzmann curve fitting successfully describes the dependence of both {{D}\\text{Brus}} and E\\text{g}\\text{opt} on UV irradiation dose.

UVER and UV index at high altitude in Northwestern Argentina.

PubMed

Utrillas, M P; Marín, M J; Esteve, A R; Salazar, G; Suarez, H; Castillo, J; Martínez-Lozano, J A

2016-10-01

Measurements of ultraviolet erythemal radiation (UVER) made during two years at three sites located at altitudes over 1000ma.s.l. in Northwestern Argentina (Salta, San Carlos, and El Rosal) have been used to estimate and analyze the UV Index (UVI) and the cumulative doses at these locations. For the UVER irradiance, data of January (maximum values) and June (minimum values) have been analyzed as representative of the year for all locations. The UVI reaches extreme (>11) values in >20% of the analyzed days in Salta (1190ma.s.l.), while these are reached in San Carlos (1611ma.s.l.) and El Rosal (3355ma.s.l.) in >40% of the analyzed days. Finally, the cumulative doses over an average year have also been studied for each location. The doses received during austral summer and autumn are of the same order, and represent one third of the annual dose, while the doses received during austral winter and spring represent one sixth of the annual dose approximately. Copyright © 2016 Elsevier B.V. All rights reserved.

Physical Methods for Seed Invigoration: Advantages and Challenges in Seed Technology

PubMed Central

Araújo, Susana de Sousa; Paparella, Stefania; Dondi, Daniele; Bentivoglio, Antonio; Carbonera, Daniela; Balestrazzi, Alma

2016-01-01

In the context of seed technology, the use of physical methods for increasing plant production offers advantages over conventional treatments based on chemical substances. The effects of physical invigoration treatments in seeds can be now addressed at multiple levels, ranging from morpho-structural aspects to changes in gene expression and protein or metabolite accumulation. Among the physical methods available, “magneto-priming” and irradiation with microwaves (MWs) or ionizing radiations (IRs) are the most promising pre-sowing seed treatments. “Magneto-priming” is based on the application of magnetic fields and described as an eco-friendly, cheap, non-invasive technique with proved beneficial effects on seed germination, vigor and crop yield. IRs, as γ-rays and X-rays, have been widely regarded as a powerful tool in agricultural sciences and food technology. Gamma-rays delivered at low dose have showed to enhance germination percentage and seedling establishment, acting as an actual ‘priming’ treatment. Different biological effects have been observed in seeds subjected to MWs and X-rays but knowledge about their impact as seed invigoration agent or stimulatory effects on germination need to be further extended. Ultraviolet (UV) radiations, namely UV-A and UV-C have shown to stimulate positive impacts on seed health, germination, and seedling vigor. For all mentioned physical treatments, extensive fundamental and applied research is still needed to define the optimal dose, exposition time, genotype- and environment-dependent irradiation conditions. Electron paramagnetic resonance has an enormous potential in seed technology not fully explored to monitor seed invigoration treatments and/or identifying the best suitable irradiation dose or time-point to stop the treatment. The present manuscript describes the use of physical methods for seed invigoration, while providing a critical discussion on the constraints and advantages. The future perspectives related to the use of these approaches to address the need of seed technologists, producers and trade markers will be also highlighted. PMID:27242847

Latitudinal variation in ambient UV-B radiation is an important determinant of Lolium perenne forage production, quality, and digestibility

PubMed Central

Comont, David; Winters, Ana; Gomez, Leonardo D; McQueen-Mason, Simon J; Gwynn-Jones, Dylan

2013-01-01

Few studies to date have considered the responses of agriculturally important forage grasses to UV-B radiation. Yet grasses such as Lolium perenne have a wide current distribution, representing exposure to a significant variation in ambient UV-B. The current study investigated the responses of L. perenne (cv. AberDart) to a simulated latitudinal gradient of UV-B exposure, representing biologically effective UV-B doses at simulated 70, 60, 50, 40, and 30° N latitudes. Aspects of growth, soluble compounds, and digestibility were assessed, and results are discussed in relation to UV-B effects on forage properties and the implications for livestock and bio-ethanol production. Aboveground biomass production was reduced by approximately 12.67% with every 1 kJ m–2 day–1 increase in biologically weighted UV-B. As a result, plants grown in the highest UV-B treatment had a total biomass of just 13.7% of controls. Total flavonoids were increased by approximately 76% by all UV-B treatments, while hydroxycinnamic acids increased in proportion to the UV-B dose. Conversely, the digestibility of the aboveground biomass and concentrations of soluble fructans were reduced by UV-B exposure, although soluble sucrose, glucose, and fructose concentrations were unaffected. These results highlight the capacity for UV-B to directly affect forage productivity and chemistry, with negative consequences for digestibility and bioethanol production. Results emphasize the need for future development and distribution of L. perenne varieties to take UV-B irradiance into consideration. PMID:23580749

Ecologically relevant UV-B dose combined with high PAR intensity distinctly affect plant growth and accumulation of secondary metabolites in leaves of Centella asiatica L. Urban.

PubMed

Müller, Viola; Albert, Andreas; Barbro Winkler, J; Lankes, Christa; Noga, Georg; Hunsche, Mauricio

2013-10-05

We investigated the effects of environmentally relevant dose of ultraviolet (UV)-B and photosynthetic active radiation (PAR) on saponin accumulation in leaves on the example of Centella asiatica L. Urban. For this purpose, plants were exposed to one of four light regimes i.e., two PAR intensities with or without UV-B radiation. The experiment was conducted in technically complex sun simulators under almost natural irradiance and climatic conditions. As observed, UV-B radiation increased herb and leaf production as well as the content of epidermal flavonols, which was monitored by non-destructive fluorescence measurements. Specific fluorescence indices also indicate an increase in the content of anthocyanins under high PAR; this increase was likewise observed for the saponin concentrations. In contrast, UV-B radiation had no distinct effects on saponin and sapogenin concentrations. Our findings suggest that besides flavonoids, also saponins were accumulated under high PAR protecting the plant from oxidative damage. Furthermore, glycosylation of sapogenins seems to be important either for the protective function and/or for compartmentalization of the compounds. Moreover, our study revealed that younger leaves contain higher amounts of saponins, while in older leaves the sapogenins were the most abundant constituents. Concluding, our results proof that ambient dose of UV-B and high PAR intensity distinctly affect the accumulation of flavonoids and saponins, enabling the plant tissue to adapt to the light conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Solar UV dose patterns in Italy.

PubMed

Meloni, D; Casale, G R; Siani, A M; Palmieri, S; Cappellani, F

2000-06-01

Since 1992 solar ultraviolet (UV) spectral irradiance (290-325 nm) has been measured at two Italian stations of Rome (urban site) and Ispra (semirural site) using Brewer spectrophotometry. The data collected under all sky conditions, are compared with the output of a sophisticated radiative transfer model (System for Transfer of Atmospheric Radiation--STAR model). The STAR multiple scattering scheme is able to cope with all physical processes relevant to the UV transfer through the atmosphere. The experience so far acquired indicates that, in spite of the unavoidable uncertainties in the input parameters (ozone, aerosol, surface albedo, pressure, temperature, relative humidity, cloud cover), measured and computed clear sky iradiances are in reasonable agreement. The STAR model is applied to build up the solar UV geographic patterns in Italy: the daily dose in the range 290-325 nm is computed at about 70 sites where a thorough and homogeneous climatology is available. For each month the concept of an idealized "standard day" is introduced and the surface distribution of solar UV field determined. The map of solar UV patterns for Italy, available for the first time, meets the study requirements in the field of skin and eye epidemiology, as well as in other investigations dealing with the impact of UV on the biosphere. The results are interpreted in terms of atmospheric and meteorological parameters modulating UV radiation reaching the ground.

Low pressure ultraviolet studies for inactivation of Giardia muris cysts.

PubMed

Hayes, S L; Rice, E W; Ware, M W; Schaefer, F W

2003-01-01

The research was initiated to confirm earlier ultraviolet (u.v.) light inactivation studies performed on Giardia cysts using excystation as the viability indicator. Following this, a comparison of in vitro excystation and animal infectivity was performed for assessing cyst viability after exposure to low-pressure u.v. irradiation. Cysts of Giardia muris were inactivated using a low-pressure u.v. light source. Giardia muris was employed as a surrogate for the human pathogen Giardia lamblia. Cyst viability was determined by both in vitro excystation and animal infectivity. Cyst doses were counted using a flow cytometer for the animal infectivity experiments. Using in vitro excystation as the viability indicator, fluences as high as approximately 200 mJ cm(-2) did not prevent some cysts from excysting, thus verifying earlier work. Using animal infectivity, u.v. fluences of 1.4, 1.9 and 2.3 mJ cm(-2) yielded log10 reductions ranging from 0.3 to >or= 4.4. Results indicate that in vitro excystation is not a reliable indicator of G. muris cyst viability after u.v. disinfection. Very low doses of u.v. light rendered G. muris cysts non-infective in the mouse model employed. Data presented represent the only complete u.v. inactivation curve for G. muris. This research provides evidence that u.v. can be an effective barrier against Giardia spp. in the treatment of drinking water supplies.

The impact of background organic matter and alkalinity on the degradation of the pesticide metaldehyde by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂.

PubMed

Autin, Olivier; Hart, Julie; Jarvis, Peter; MacAdam, Jitka; Parsons, Simon A; Jefferson, Bruce

2013-04-15

The impact of background constituents on the degradation of trace levels of micropollutants by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂ was studied. Experimental results demonstrated that the background scavenging rate rather than the concentration of micropollutant controls the required UV irradiation dose. The character of the natural organic matter had a limited impact on scavenging when the water source remains unchanged, however, a periodic bleed of hydrophobic material may substantially increase the minimum UV dose required to reach the desired micropollutant concentration. Moreover, in the case of UV/TiO₂, high concentrations of background organic matter do not only act as scavengers but also saturate the TiO₂ surface. Alkalinity inhibits the efficacy of UV/TiO₂ photocatalysis due to the formation of large TiO₂ aggregates. The study also demonstrated that the use of synthetic waters for treatability test purposes was an acceptable approach as long as both the background organic matter and the alkalinity were matched to that of the projected application. Finally spiking micropollutants at higher concentrations does not alter the significance of the findings as long as the background constituents represent more than 85% of the total scavenging rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Direct-to-diffuse UV Solar Irradiance Ratio for a UV rotating Shadowband Spectroradiometer and a UV Multi-filter Rotating Shadowband Radiometer

NASA Astrophysics Data System (ADS)

Lantz, K.; Kiedron, P.; Petropavlovskikh, I.; Michalsky, J.; Slusser, J.

2008-12-01

. Two spectroradiometers reside that measure direct and diffuse UV solar irradiance are located at the Table Mountain Test Facility, 8 km north of Boulder, CO. The UV- Rotating Shadowband Spectrograph (UV-RSS) measures diffuse and direct solar irradiance from 290 - 400 nm. The UV Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR) measures diffuse and direct solar irradiance in seven 2-nm wide bands, i.e. 300, 305, 311, 317, 325, and 368 nm. The purpose of the work is to compare radiative transfer model calculations (TUV) with the results from the UV-Rotating Shadowband Spectroradiometer (UV-RSS) and the UV-MFRSR to estimate direct-to-diffuse solar irradiance ratios (DDR) that are used to evaluate the possibility of retrieving aerosol single scattering albedo (SSA) under a variety of atmospheric conditions: large and small aerosol loading, large and small surface albedo. For the radiative transfer calculations, total ozone measurements are obtained from a collocated Brewer spectrophotometer.

Excess processing of oxidative damaged bases causes hypersensitivity to oxidative stress and low dose rate irradiation.

PubMed

Yoshikawa, Y; Yamasaki, A; Takatori, K; Suzuki, M; Kobayashi, J; Takao, M; Zhang-Akiyama, Q-M

2015-10-01

Ionizing radiations such as X-ray and γ-ray can directly or indirectly produce clustered or multiple damages in DNA. Previous studies have reported that overexpression of DNA glycosylases in Escherichia coli (E. coli) and human lymphoblast cells caused increased sensitivity to γ-ray and X-ray irradiation. However, the effects and the mechanisms of other radiation, such as low dose rate radiation, heavy-ion beams, or hydrogen peroxide (H2O2), are still poorly understood. In the present study, we constructed a stable HeLaS3 cell line overexpressing human 8-oxoguanine DNA N-glycosylase 1 (hOGG1) protein. We determined the survival of HeLaS3 and HeLaS3/hOGG1 cells exposed to UV, heavy-ion beams, γ-rays, and H2O2. The results showed that HeLaS3 cells overexpressing hOGG1 were more sensitive to γ-rays, OH(•), and H2O2, but not to UV or heavy-ion beams, than control HeLaS3. We further determined the levels of 8-oxoG foci and of chromosomal double-strand breaks (DSBs) by detecting γ-H2AX foci formation in DNA. The results demonstrated that both γ-rays and H2O2 induced 8-oxoguanine (8-oxoG) foci formation in HeLaS3 cells. hOGG1-overexpressing cells had increased amounts of γ-H2AX foci and decreased amounts of 8-oxoG foci compared with HeLaS3 control cells. These results suggest that excess hOGG1 removes the oxidatively damaged 8-oxoG in DNA more efficiently and therefore generates more DSBs. Micronucleus formation also supported this conclusion. Low dose-rate γ-ray effects were also investigated. We first found that overexpression of hOGG1 also caused increased sensitivity to low dose rate γ-ray irradiation. The rate of micronucleus formation supported the notion that low dose rate irradiation increased genome instability.

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.

Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

NASA Astrophysics Data System (ADS)

Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

2018-03-01

Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

Comparison between UV and VUV photolysis for the pre- and post-treatment of coking wastewater.

PubMed

Xing, Rui; Zheng, Zhongyuan; Wen, Donghui

2015-03-01

In this study, ultraviolet (UV) and vacuum ultraviolet (VUV) photolysis were investigated for the pre-treatment and post-treatment of coking wastewater. First, 6-fold diluted raw coking wastewater was irradiated by UV and VUV. It was found that 15.9%-35.4% total organic carbon (TOC) was removed after 24 hr irradiation. The irradiated effluent could be degraded by the acclimated activated sludge. Even though the VUV photolysis removed more chemical oxygen demand (COD) than UV, the UV-irradiated effluent demonstrated better biodegradability. After 4 hr UV irradiation, the biological oxygen demand BOD5/COD ratio of irradiated coking wastewater increased from 0.163 to 0.224, and its toxicity decreased to the greatest extent. Second, the biologically treated coking wastewater was irradiated by UV and VUV. Both of them were able to remove 37%-47% TOC within 8 hr irradiation. Compared to UV, VUV photolysis could significantly improve the transparency of the bio-treated effluent. VUV also reduced 7% more ammonia nitrogen (NH4+-N), 17% more nitrite nitrogen (NO2--N), and 18% more total nitrogen (TN) than UV, producing 35% less nitrite nitrogen (NO3--N) as a result. In conclusion, UV irradiation was better in improving the biodegradability of coking wastewater, while VUV was more effective at photolyzing the residual organic compounds and inorganic N-species in the bio-treated effluent. Copyright © 2015. Published by Elsevier B.V.

In Vitro Repair of UV-Irradiated Micrococcus luteus Bacteriophage N1 Transfecting DNA 1

PubMed Central

Mahler, Inga; George, Jeanne; Grossman, Lawrence

1974-01-01

Calcium-treated UV-sensitive, host cell reactivation− strains of Micrococcus luteus are infected with UV-irradiated N1 DNA. In strains lacking UV endonuclease, in vitro treatment of the irradiated DNA results in transfection enhancement. PMID:4823319

UV-C irradiation delays mitotic progression by recruiting Mps1 to kinetochores

PubMed Central

Zhang, Xiaojuan; Ling, Youguo; Wang, Wenjun; Zhang, Yanhong; Ma, Qingjun; Tan, Pingping; Song, Ting; Wei, Congwen; Li, Ping; Liu, Xuedong; Ma, Runlin Z.; Zhong, Hui; Cao, Cheng; Xu, Quanbin

2013-01-01

The effect of UV irradiation on replicating cells during interphase has been studied extensively. However, how the mitotic cell responds to UV irradiation is less well defined. Herein, we found that UV-C irradiation (254 nm) increases recruitment of the spindle checkpoint proteins Mps1 and Mad2 to the kinetochore during metaphase, suggesting that the spindle assembly checkpoint (SAC) is reactivated. In accordance with this, cells exposed to UV-C showed delayed mitotic progression, characterized by a prolonged chromosomal alignment during metaphase. UV-C irradiation also induced the DNA damage response and caused a significant accumulation of γ-H2AX on mitotic chromosomes. Unexpectedly, the mitotic delay upon UV-C irradiation is not due to the DNA damage response but to the relocation of Mps1 to the kinetochore. Further, we found that UV-C irradiation activates Aurora B kinase. Importantly, the kinase activity of Aurora B is indispensable for full recruitment of Mps1 to the kinetochore during both prometaphase and metaphase. Taking these findings together, we propose that UV irradiation delays mitotic progression by evoking the Aurora B-Mps1 signaling cascade, which exerts its role through promoting the association of Mps1 with the kinetochore in metaphase. PMID:23531678

UV exposure in cars.

PubMed

Moehrle, Matthias; Soballa, Martin; Korn, Manfred

2003-08-01

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

Epilobium angustifolium extract demonstrates multiple effects on dermal fibroblasts in vitro and skin photo-protection in vivo.

PubMed

Ruszová, Ema; Cheel, José; Pávek, Stanislav; Moravcová, Martina; Hermannová, Martina; Matějková, Ilona; Spilková, Jiřina; Velebný, Vladimír; Kubala, Lukáš

2013-09-01

Stress-induced fibroblast senescence is thought to contribute to skin aging. Ultraviolet light (UV) radiation is the most potent environmental risk factor in these processes. An Epilobium angustifolium (EA) extract was evaluated for its capacity to reverse the senescent response of normal human dermal fibroblasts (NHDF) in vitro and to exhibit skin photo-protection in vivo. The HPLC-UV-MS analysis of the EA preparation identified three major polyphenol groups: tannins (oenothein B), phenolic acids (gallic and chlorogenic acids) and flavonoids. EA extract increased the cell viability of senescent NHDF induced by serum deprivation. It diminished connective tissue growth factor and fibronectin gene expressions in senescent NHDF. Down-regulation of the UV-induced release of both matrix metalloproteinase-1 and -3 and the tissue inhibitor of matrix metalloproteinases-1 and -2, and also down-regulation of the gene expression of hyaluronidase 2 were observed in repeatedly UV-irradiated NHDF after EA extract treatment. Interestingly, EA extract diminished the down-regulation of sirtuin 1 dampened by UV-irradiation. The application of EA extract using a sub-irritating dose protected skin against UV-induced erythema formation in vivo. In summary, EA extract diminished stress-induced effects on NHDF, particularly on connective tissue growth factor, fibronectin and matrix metalloproteinases. These results collectively suggest that EA extract may possess anti-aging properties and that the EA polyphenols might account for these benefits.

Deletion of epidermal Rac1 inhibits HPV-8 induced skin papilloma formation and facilitates HPV-8- and UV-light induced skin carcinogenesis

PubMed Central

Deshmukh, Jayesh; Pofahl, Ruth; Pfister, Herbert; Haase, Ingo

2016-01-01

Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has not been investigated so far, solar UV radiation being an important carcinogen to the skin. To investigate this, we deleted Rac1 or modulated its activity in mice with transgenic expression of Human papilloma virus type-8 (HPV-8) in epidermal keratinocytes. Our data show that inhibition or deletion of Rac1 results in reduced papilloma formation upon UV-irradiation with a single dose, whereas constitutive activation of Rac1 strongly increases papilloma frequency in these mice. Surprisingly, we observed that, upon chronic UV-irradiation, the majority of mice with transgenic expression of HPV-8 and epidermis specific Rac1 deletion developed squamous cell carcinomas. Taken together, our data show that Rac1 exerts a dual role in skin carcinogenesis: its activation is, on one hand, required for HPV-8- and UV-light induced papilloma formation but, on the other, suppresses the development of squamous cell carcinomas. PMID:27506937

Deletion of epidermal Rac1 inhibits HPV-8 induced skin papilloma formation and facilitates HPV-8- and UV-light induced skin carcinogenesis.

PubMed

Deshmukh, Jayesh; Pofahl, Ruth; Pfister, Herbert; Haase, Ingo

2016-09-06

Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has not been investigated so far, solar UV radiation being an important carcinogen to the skin.To investigate this, we deleted Rac1 or modulated its activity in mice with transgenic expression of Human papilloma virus type-8 (HPV-8) in epidermal keratinocytes. Our data show that inhibition or deletion of Rac1 results in reduced papilloma formation upon UV-irradiation with a single dose, whereas constitutive activation of Rac1 strongly increases papilloma frequency in these mice. Surprisingly, we observed that, upon chronic UV-irradiation, the majority of mice with transgenic expression of HPV-8 and epidermis specific Rac1 deletion developed squamous cell carcinomas. Taken together, our data show that Rac1 exerts a dual role in skin carcinogenesis: its activation is, on one hand, required for HPV-8- and UV-light induced papilloma formation but, on the other, suppresses the development of squamous cell carcinomas.

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

PubMed

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

2000-08-01

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

Integrated chemical and toxicological investigation of UV-chlorine/chloramine drinking water treatment.

PubMed

Lyon, Bonnie A; Milsk, Rebecca Y; DeAngelo, Anthony B; Simmons, Jane Ellen; Moyer, Mary P; Weinberg, Howard S

2014-06-17

As the use of alternative drinking water treatment increases, it is important to understand potential public health implications associated with these processes. The objective of this study was to evaluate the formation of disinfection byproducts (DBPs) and cytotoxicity of natural organic matter (NOM) concentrates treated with chlorine, chloramine, and medium pressure ultraviolet (UV) irradiation followed by chlorine or chloramine, with and without nitrate or iodide spiking. The use of concentrated NOM conserved volatile DBPs and allowed for direct analysis of the treated water. Treatment with UV prior to chlorine in ambient (unspiked) samples did not affect cytotoxicity as measured using an in vitro normal human colon cell (NCM460) assay, compared to chlorination alone when toxicity is expressed on the basis of dissolved organic carbon (DOC). Nitrate-spiked UV+chlorine treatment produced greater cytotoxicity than nitrate-spiked chlorine alone or ambient UV+chlorine samples, on both a DOC and total organic halogen basis. Samples treated with UV+chloramine were more cytotoxic than those treated with only chloramine using either dose metric. This study demonstrated the combination of cytotoxicity and DBP measurements for process evaluation in drinking water treatment. The results highlight the importance of dose metric when considering the relative toxicity of complex DBP mixtures formed under different disinfection scenarios.

Synthesis and characterization of silver/diatomite nanocomposite by electron beam irradiation

NASA Astrophysics Data System (ADS)

Hanh, Truong Thi; Thu, Nguyen Thi; Quoc, Le Anh; Hien, Nguyen Quoc

2017-10-01

Silver nanoparticles (AgNPs) with diameter about 9 nm were deposited on diatomite by irradiation under electron beam of diatomite suspension containing 10 mM AgNO3 in 1% chitosan solution, at the dose of 20.2 kGy. The AgNPs/diatomite nanocomposite was characterized by UV-Vis spectroscopy, TEM image and energy dispersive X-ray spectroscopy (EDX). The antibacterial activity of the AgNPs/diatomite against E. coli and S. aureus was evaluated by reduction of bacterial colonies on spread plates and inhibition zone diameter on diffusion disks.

Standardization of UV LED measurements

NASA Astrophysics Data System (ADS)

Eppeldauer, G. P.; Larason, T. C.; Yoon, H. W.

2015-09-01

Traditionally used source spectral-distribution or detector spectral-response based standards cannot be applied for accurate UV LED measurements. Since the CIE standardized rectangular-shape spectral response function for UV measurements cannot be realized with small spectral mismatch when using filtered detectors, the UV measurement errors can be several times ten percent or larger. The UV LEDs produce broadband radiation and both their peaks or spectral bandwidths can change significantly. The detectors used for the measurement of these LEDs also have different spectral bandwidths. In the discussed example, where LEDs with 365 nm peak are applied for fluorescent crack-recognition using liquid penetrant (non-destructive) inspection, the broadband radiometric LED (signal) measurement procedure is standardized. A UV LED irradiance-source was calibrated against an FEL lamp standard to determine its spectral irradiance. The spectral irradiance responsivity of a reference UV meter was also calibrated. The output signal of the reference UV meter was calculated from the spectral irradiance of the UV source and the spectral irradiance responsivity of the reference UV meter. From the output signal, both the integrated irradiance (in the reference plane of the reference meter) and the integrated responsivity of the reference meter were determined. Test UV meters calibrated for integrated responsivity against the reference UV meter, can be used to determine the integrated irradiance from a field UV source. The obtained 5 % (k=2) measurement uncertainty can be decreased when meters with spectral response close to a constant value are selected.

Effect of chemical peeling on the skin in relation to UV irradiation.

PubMed

Funasaka, Yoko; Abdel-Daim, Mohamed; Kawana, Seiji; Nishigori, Chikako

2012-07-01

Chemical peeling is one of the dermatological treatments available for certain cutaneous diseases and conditions or improvement of cosmetic appearance of photoaged skin. However, it needs to be clarified whether the repetitive procedure of chemical peeling on photodamaged skin is safe and whether the different chemicals used for peeling results in similar outcomes or not. In this article, we reviewed the effect of peeling or peeling agents on the skin in relation to ultraviolet (UV) radiation. The pretreatment of peeling agents usually enhance UV sensitivity by inducing increased sunburn cell formation, lowering minimum erythematous dose and increasing cyclobutane pyrimidine dimers. However, this sensitivity is reversible and recovers to normal after 1-week discontinuation. Using animals, the chronic effect of peeling and peeling agents was shown to prevent photocarcinogenesis. There is also an in vitro study using culture cells to know the detailed mechanisms of peeling agents, especially on cell proliferation and apoptotic changes via activating signalling cascades and oxidative stress. It is important to understand the effect of peeling agents on photoaged skin and to know how to deal with UV irradiation during the application of peeling agents and treatment of chemical peeling in daily life. © 2012 John Wiley & Sons A/S.

Is it photosensitization or photodegradation when UV-B irradiation is combined with BDE-47? Evidence from the growth and reproduction changes of rotifer Brachionus plicatilis.

PubMed

Liu, Chunchen; Tang, Xuexi; Zhou, Bin; Jiang, Yongshun; Lv, Mengchen; Zang, Yu; Wang, You

2018-07-01

Ecotoxicological methods were applied in the present study, and the marine rotifer Brachionus plicatilis was used as the toxic endpoint to depict what occurred when 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was combined with solar ultraviolet-B radiation (UV-B). B. plicatilis was exposed to three different combination methods of BDE-47 and UV-B at an equal toxicity ratio, including normal rotifer co-cultured with UV-B-irradiated BDE-47 (known as Method I), UV-B-irradiated rotifer co-cultured with BDE-47 exposure (known as Method II) and normal rotifer co-cultured with the simultaneous addition of BDE-47 and UV-B irradiation (known as Method III). Acute and chronic experiments were preformed to determine the toxicity differentiation according to the growth and reproduction changes in the rotifer. Twenty-four-hour acute experiments showed that the modes of three combined methods changed from antagonism to additive, to synergistic with the concentration/dose increment, and the contribution rates of Method I and Method II to Method III were calculated by approximately 40.4% and 59.6%, respectively. Chronic exposure to either the single stressor or the combination of stressors inhibited the growth and reproduction of the rotifer, demonstrating the inhibition of the population growth rate and the decrease in the larvae production. Three combined groups presented more serious damages compared to groups with single stress exposure, and the ascending sequence of toxicity was Method I

Effect of supplemental UV-A irradiation in solid-state lighting on the growth and phytochemical content of microgreens

NASA Astrophysics Data System (ADS)

Brazaitytė, A.; Viršilė, A.; Jankauskienė, J.; Sakalauskienė, S.; Samuolienė, G.; Sirtautas, R.; Novičkovas, A.; Dabašinskas, L.; Miliauskienė, J.; Vaštakaitė, V.; Bagdonavičienė, A.; Duchovskis, P.

2015-01-01

In this study, we sought to find and employ positive effects of UV-A irradiation on cultivation and quality of microgreens. Therefore, the goal of our study was to investigate the influence of 366, 390, and 402 nm UV-A LED wavelengths, supplemental for the basal solid-state lighting system at two UV-A irradiation levels on the growth and phytochemical contents of different microgreen plants. Depending on the species, supplemental UV-A irradiation can improve antioxidant properties of microgreens. In many cases, a significant increase in the investigated phytochemicals was found under 366 and 390 nm UV-A wavelengths at the photon flux density (12.4 μmol m-2 s-1). The most pronounced effect of supplemental UV-A irradiation was detected in pak choi microgreens. Almost all supplemental UV-A irradiation treatments resulted in increased leaf area and fresh weight, in higher 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging activity, total phenols, anthocyanins, ascorbic acid, and α-tocopherol.

Measurement of metabolite variations and analysis of related gene expression in Chinese liquorice (Glycyrrhiza uralensis) plants under UV-B irradiation.

PubMed

Zhang, Xiao; Ding, Xiaoli; Ji, Yaxi; Wang, Shouchuang; Chen, Yingying; Luo, Jie; Shen, Yingbai; Peng, Li

2018-04-18

Plants respond to UV-B irradiation (280-315 nm wavelength) via elaborate metabolic regulatory mechanisms that help them adapt to this stress. To investigate the metabolic response of the medicinal herb Chinese liquorice (Glycyrrhiza uralensis) to UV-B irradiation, we performed liquid chromatography tandem mass spectrometry (LC-MS/MS)-based metabolomic analysis, combined with analysis of differentially expressed genes in the leaves of plants exposed to UV-B irradiation at various time points. Fifty-four metabolites, primarily amino acids and flavonoids, exhibited changes in levels after the UV-B treatment. The amino acid metabolism was altered by UV-B irradiation: the Asp family pathway was activated and closely correlated to Glu. Some amino acids appeared to be converted into antioxidants such as γ-aminobutyric acid and glutathione. Hierarchical clustering analysis revealed that various flavonoids with characteristic groups were induced by UV-B. In particular, the levels of some ortho-dihydroxylated B-ring flavonoids, which might function as scavengers of reactive oxygen species, increased in response to UV-B treatment. In general, unigenes encoding key enzymes involved in amino acid metabolism and flavonoid biosynthesis were upregulated by UV-B irradiation. These findings lay the foundation for further analysis of the mechanism underlying the response of G. uralensis to UV-B irradiation.

UV-induced changes of active components and antioxidant activity in postharvest pigeon pea [Cajanus cajan (L.) Millsp.] leaves.

PubMed

Wei, Zuo-Fu; Luo, Meng; Zhao, Chun-Jian; Li, Chun-Ying; Gu, Cheng-Bo; Wang, Wei; Zu, Yuan-Gang; Efferth, Thomas; Fu, Yu-Jie

2013-02-13

In this study, the effect of UV irradiation (UV-A, UV-B, and UV-C) on phytochemicals, total phenolics, and antioxidant activity of postharvest pigeon pea leaves was evaluated. The response of pigeon pea leaves to UV irradiation was phytochemical specific. UV-B and UV-C induced higher levels of phytochemicals, total phenolics, and antioxidant activity in pigeon pea leaves compared with UV-A. Furthermore, UV-B irradiation proved to possess a long-lasting effect on the levels of phenolics and antioxidant activity. After adapting for 48 h at 4 °C following 4 h UV-B irradiation, total phenolics and antioxidant activity were approximately 1.5-fold and 2.2-fold increased from 39.4 mg GAE/g DM and 15.0 μmol GAE/g DM to 59.1 mg GAE/g DM and 32.5 μmol GAE/g DM, respectively. These results indicate that UV irradiation of pigeon pea leaves can be beneficial in terms of increasing active components and antioxidant activity.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

The aim of this study is to validate the Ozone Monitoring Instrument (OMI) erythemal dose rates using ground-based measurements in Thessaloniki, Greece. In the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, a Yankee Environmental System UVB-1 radiometer measures the erythemal dose rates every minute, and a Norsk Institutt for Luftforskning (NILU) multi-filter radiometer provides multi-filter based irradiances that were used to derive erythemal dose rates for the period 2005-2014. Both these datasets were independently validated against collocated UV irradiance spectra from a Brewer MkIII spectrophotometer. Cloud detection was performed based on measurements of the global horizontal radiation from a Kipp & Zonen pyranometer and from NILU measurements in the visible range. The satellite versus ground observation validation was performed taking into account the effect of temporal averaging, limitations related to OMI quality control criteria, cloud conditions, the solar zenith angle and atmospheric aerosol loading. Aerosol optical depth was also retrieved using a collocated CIMEL sunphotometer in order to assess its impact on the comparisons. The effect of total ozone columns satellite versus ground-based differences on the erythemal dose comparisons was also investigated. Since most of the public awareness alerts are based on UV Index (UVI) classifications, an analysis and assessment of OMI capability for retrieving UVIs was also performed. An overestimation of the OMI erythemal product by 3-6% and 4-8% with respect to ground measurements is observed when examining overpass and noontime estimates respectively. The comparisons revealed a relatively small solar zenith angle dependence, with the OMI data showing a slight dependence on aerosol load, especially at high aerosol optical depth values. A mean underestimation of 2% in OMI total ozone columns under cloud-free conditions was found to lead to an overestimation in OMI erythemal doses of 1-5%.While OMI overestimated the erythemal dose rates over the range of cloudiness conditions examined, its UVIs were found to be reliable for the purpose of characterizing the ambient UV radiation impact.

Prebiotic chemistry: chemical evolution of organics on the primitive Earth under simulated prebiotic conditions.

PubMed

Dondi, Daniele; Merli, Daniele; Pretali, Luca; Fagnoni, Maurizio; Albini, Angelo; Serpone, Nick

2007-11-01

A series of prebiotic mixtures of simple molecules, sources of C, H, N, and O, were examined under conditions that may have prevailed during the Hadean eon (4.6-3.8 billion years), namely an oxygen-free atmosphere and a significant UV radiation flux over a large wavelength range due to the absence of an ozone layer. Mixtures contained a C source (methanol, acetone or other ketones), a N source (ammonia or methylamine), and an O source (water) at various molar ratios of C : H : N : O. When subjected to UV light or heated for periods of 7 to 45 days under an argon atmosphere, they yielded a narrow product distribution of a few principal compounds. Different initial conditions produced different distributions. The nature of the products was ascertained by gas chromatographic-mass spectral analysis (GC-MS). UVC irradiation of an aqueous methanol-ammonia-water prebiotic mixture for 14 days under low UV dose (6 x 10(-2) Einstein) produced methylisourea, hexamethylenetetramine (HMT), methyl-HMT and hydroxy-HMT, whereas under high UV dose (45 days; 1.9 x 10(-1) Einstein) yielded only HMT. By contrast, the prebiotic mixture composed of acetone-ammonia-water produced five principal species with acetamide as the major component; thermally the same mixture produced a different product distribution of four principal species. UVC irradiation of the CH(3)CN-NH(3)-H(2)O prebiotic mixture for 7 days gave mostly trimethyl-s-triazine, whereas in the presence of two metal oxides (TiO(2) or Fe(2)O(3)) also produced some HMT; the thermal process yielded only acetamide.

Space-based estimation of the solar UV-B doses for psoriasis heliotherapy in Poland using OMI data for the period 2005-2011.

PubMed

Krzyścin, J W; Jarosławski, J; Rajewska-Więch, B; Sobolewski, P S; Narbutt, J; Lesiak, A; Pawlaczyk, M; Janouch, M

2012-12-05

A UV model is proposed to reconstruct the biologically weighted doses at the ground-level, erythemal, vitamin D(3), and antipsoriatic effective doses, based on the space data from the Ozone Monitoring Instrument on board of NASA EOS Aura spacecraft for the period 2005-2011. The model is training using the results of spectral UV measurements carried out at Belsk, Poland. The model outcome is verified using the UV spectra measured at Hradec Kralove, Czech Republic. The model uncertainty is almost the same for all examined action spectra and comparable to that found in earlier studies on differences between the satellite overpasses and ground-based erythemal data. Antipsoriatic doses, taken during 2h exposure periods near local noon, are reconstructed for selected sites in Poland to find if heliotherapy would be an alternative to standard treatment of psoriasis by tube irradiation in medical cabinets. Mountain-resort in the southern Poland, Zakopane, and rural-site in Central Poland, Belsk, are among the best location of potential heliotherapy centers in Poland for late spring/summer season. Łeba, resort on the Baltic Sea coast, is a potential heliotherapy center in June and July. The methodology to disclose possible heliotherapy periods over the territory of Poland could be extended to any region. It would help to prepare an optimal schedule of antipsoriatic heliotherapy that accounts for local weather conditions and medical standards of using UV cabinets. Copyright © 2012 Elsevier B.V. All rights reserved.

A proposal for in vitro/GFR molecular erythema action spectrum

NASA Astrophysics Data System (ADS)

de Souza, João A. V.; Lorenzini, Fabiane; Rizzatti, Mara R.

2008-08-01

We propose an erythema action spectrum based on experimental molecular measurements named molecular erythema action spectrum or in vitro/GFR, where the acronym GFR represents our research group name, Grupo de Física das Radiaçöes. The in vitro methodology was developed by using a derma tissue simulator (TSD), as a radiation protection shield, and monochromatic ultraviolet (UV) sources of 254, 310, 365, 380, and 400 nm. The irradiance from each source was monitored through spectroradiometry in order to obtain the exposure dose over a period of time. Changes in the chemical structure were monitored by Fourier transform infrared spectroscopy (FTIR) and UV and visible spectroscopy (UV-vis). The samples were analyzed by UV-vis at each 200 up to 1000 J/m2 and at each 400 up to 2000 J/m2. FTIR was performed only for samples exposed to a maximum dose of 2000 J/m2. The in vitro action parameters were obtained by considering the redshift revealed through UV-vis analysis, as being the molecular quantification of minimal erythema, and the chemical bond rupture of TSD molecules associated with erythema, revealed through FTIR. The in vitro/GFR action spectrum shows that UV-A and UV-B radiation are equally responsible for the damage observed in TSD. When this proposal was compared to the CIE erythema action spectrum from ISO [ISO17166 CIE S 007/E, Erythema Reference Action Spectrum and Standard Erythema Dose (CIE Central Bureau, Austria, 1998)], similarities could be observed in wavelengths less than 280 nm in UV-B region. However, for wavelengths higher than 300 nm, the efficiency of this radiation to induce damage, mainly in the UV-A part, was much higher than predicted in CIE model. The increasing concern on UV-A radiation, assumed to be as responsible as UV-B for inducing most of the already observed skin injuries, may be better understood when observing the experimental model presented in in vitro/GFR action spectrum.

Tomato plants use non-enzymatic antioxidant pathways to cope with moderate UV-A/B irradiation: A contribution to the use of UV-A/B in horticulture.

PubMed

Mariz-Ponte, N; Mendes, R J; Sario, S; Ferreira de Oliveira, J M P; Melo, P; Santos, C

2018-02-01

Plants developed receptors for solar UV-A/B radiation, which regulate a complex network of functions through the plant's life cycle. However, greenhouse grown crops, like tomato, are exposed to strongly reduced UV radiation, contrarily to their open-field counterparts. A new paradigm of modern horticulture is to supplement adequate levels of UV to greenhouse cultures, inducing a positive mild stress necessary to stimulate oxidative stress pathways and antioxidant mechanisms. Protected cultures of Solanum (cv MicroTom) were supplemented with moderate UV-A (1h and 4h) and UV-B (1min and 5min) doses during the flowering/fruiting period. After 30days, flowering/fruit ripening synchronization were enhanced, paralleled by the upregulation of blue/UV-A and UV-B receptors' genes cry1a and uvr8. UV-B caused moreover an increase in the expression of hy5, of HY5 repressor cop1 and of a repressor of COP1, uvr8. While all UV-A/B conditions increased SOD activity, increases of the generated H 2 O 2 , as well as lipid peroxidation and cell mebrane disruption, were minimal. However, the activity of antioxidant enzymes downstream from SOD (CAT, APX, GPX) was not significant. These results suggest that the major antioxidant pathways involve phenylpropanoid compounds, which also have an important role in UV screening. This hypothesis was confirmed by the increase of phenolic compounds and by the upregulation of chs and fls, coding for CHS and FLS enzymes involved in the phenylpropanoid synthesis. Overall, all doses of UV-A or UV-B were beneficial to flowering/fruiting but lower UV-A/B doses induced lower redox disorders and were more effective in the fruiting process/synchronization. Considering the benefits observed on flowering/fruiting, with minimal impacts in the vegetative part, we demonstrate that both UV-A/B could be used in protected tomato horticulture systems. Copyright © 2017 Elsevier GmbH. All rights reserved.

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.

Performance improvement of pentacosa-diynoic acid label dosimeter for radiation processing technology

NASA Astrophysics Data System (ADS)

Abdel-Fattah, A. A.; Soliman, Y. S.

2017-12-01

A radiation sensitive material, 10,12-pentacosa-diynoic acid (PCDA), was incorporated into polyvinyl butyral (PVB) films to develop indicators/dosimeters for blood and food irradiation. The present study aims to improve the dosimetric performance of these previously prepared dosimeters and to extend their shelf life by the combination of a radical scavenger, propyl gallate (PG), and a UV absorber, tinuvin-p (TP). The X-ray diffraction (XRD) patterns of the dosimeters were analysed and their dosimetric characteristics were investigated by specular reflectance in the visible spectrum range of 400-700 nm. Upon irradiation, the films turn blue exhibiting two main bands around 670 and 620 nm. Their dose-response functions were fitted by a double exponential growth, 5 parameters, equation. Irradiation temperature influences the dosimeter response at 670 nm without causing thermochromic transition up to 50 °C in poly-PCDA. The useful dose range is 5-4000 Gy depending on the wavelengths of analysis and PCDA content in the films. The overall uncertainty of dose measurement is less than 6% at 2σ.

Ultraviolet blood irradiation: Is it time to remember "the cure that time forgot"?

PubMed

Wu, Ximing; Hu, Xiaoqing; Hamblin, Michael R

2016-04-01

Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma, and even poliomyelitis. The early studies were carried out by several physicians in USA and published in the American Journal of Surgery. However, with the development of antibiotics, the use of UBI declined and it has now been called "the cure that time forgot." Later studies were mostly performed by Russian workers, and in other Eastern countries, and the modern view in Western countries is that UBI remains highly controversial. This review discusses the potential of UBI as an alternative approach to current methods used to treat infections, as an immune-modulating therapy and as a method for normalizing blood parameters. Low and mild doses of UV kill microorganisms by damaging the DNA, while any DNA damage in host cells can be rapidly repaired by DNA repair enzymes. However, the use of UBI to treat septicemia cannot be solely due to UV-mediated killing of bacteria in the bloodstream, as only 5-7% of blood volume needs to be treated with UV to produce the optimum benefit, and higher doses can be damaging. There may be some similarities to extracorporeal photopheresis (ECP) using psoralens and UVA irradiation. However, there are differences between UBI and ECP in that UBI tends to stimulate the immune system, while ECP tends to be immunosuppressive. With the recent emergence of bacteria that are resistant to all known antibiotics, UBI should be more investigated as an alternative approach to infections, and as an immune-modulating therapy. Copyright © 2016. Published by Elsevier B.V.

Ultraviolet blood irradiation: Is it time to remember “the cure that time forgot”?

PubMed Central

Wu, Ximing; Hu, Xiaoqing; Hamblin, Michael R.

2016-01-01

Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma and even poliomyelitis. The early studies were carried out by several physicians in USA and published in the American Journal of Surgery. However with the development of antibiotics, the use of UBI declined and it has now been called “the cure that time forgot”. Later studies were mostly performed by Russian workers and in other Eastern countries, and the modern view in Western countries is that UBI remains highly controversial. This review discusses the potential of UBI as an alternative approach to current methods used to treat infections, as an immune-modulating therapy and as a method for normalizing blood parameters. Low and mild doses of UV kill microorganisms by damaging the DNA, while any DNA damage in host cells can be rapidly repaired by DNA repair enzymes. However the use of UBI to treat septicemia cannot be solely due to UV-mediated killing of bacteria in the bloodstream, as only 5–7% of blood volume needs to be treated with UV to produce the optimum benefit, and higher doses can be damaging. There may be some similarities to extracorporeal photopheresis (ECP) using psoralens and UVA irradiation. However there are differences between UBI and ECP in that UBI tends to stimulate the immune system, while ECP tends to be immunosuppressive. With the recent emergence of bacteria that are resistant to all known antibiotics, UBI should be more investigated as an alternative approach to infections, and as an immune-modulating therapy. PMID:26894849

Influence of UV irradiation on hydroxypropyl methylcellulose polymer films

NASA Astrophysics Data System (ADS)

Rao, B. Lakshmeesha; Shivananda, C. S.; Shetty, G. Rajesha; Harish, K. V.; Madhukumar, R.; Sangappa, Y.

2018-05-01

Hydroxypropyl Methylcellulose (HPMC) biopolymer films were prepared by solution casting technique and effects of UV irradiation on the structural and optical properties of the polymer films were analysed using X-ray Diffraction and UV-Visible studies. From XRD data, the microcrystalline parameters (crystallite size (LXRD) and crystallinity (Xc)) were calculated and found to be decreasing with UV irradiation due to photo-degradation process. From the UV-Vis absorption data, the optical bandgap (Eg), average numbers of carbon atoms per conjugation length (N) of the polymer chain and the refractive index (n) at 550 nm (average wavelength of visible light) of virgin and UV irradiated HPMC films were calculated. With increase in UV exposure time, the optical bandgap energy (Eg) increases, and hence average number of carbon atoms per conjugation length (N) decreases, supports the photo-degradation of HPMC polymer films. The refractive index of the HPMC films decreases after UV irradiation, due to photo-degradation induced chain rearrangements.

Characterization and application of two kinds of ESR dosimeters

NASA Astrophysics Data System (ADS)

Marchioni, Eric; Pabst, Jean-Yves; Kuntz, Florent

2002-09-01

Many previous papers described the use of low-concentration alanine pellets, powder or films for industrial high-dose application, but very few authors presented applications of such dosimeters to the low-dose range used for wastewater, flowers or radiotherapy treatment. The present paper describes the large-scale manufacturing process of high-concentration alanine pellets used for radiotherapy dose control in some French hospitals. The fading process due to sunlight exposure has been evaluated by means of direct UV light irradiation. The major disadvantage of alanine is its strong solubility in water (the pellets are completely dissolved when immersed for 10 min in pure water). The use of barium sulphate, not soluble in water, made it possible to carry out dosimetric measurements even when the dosimeter is completely immersed in water or stored after irradiation in high humidity levels. The paper presents manufacturing process of barium sulphate pellets, their dosimetric characteristics and one application of this dosimeter for the control of the absorbed doses during wastewater treatments.

Narrowband UV-B phototherapy in the treatment of cutaneous graft versus host disease.

PubMed

Grundmann-Kollmann, Marcella; Martin, Hans; Ludwig, Ralf; Klein, Stefan; Boehncke, Wolf-Henning; Hoelzer, Dieter; Kaufmann, Roland; Podda, Maurizio

2002-12-15

Graft versus host disease (GVHD) is an important problem following allogenic bone marrow transplantation (BMT). The beneficial effects of photochemotherapy with psoralens plus UVA irradiation (PUVA) have been described repeatedly; however, PUVA is limited by a wide range of unwanted effects. A novel improved form of UV-B phototherapy, narrowband UV-B, has been proven to be very effective in T-cell mediated dermatoses. Therefore, we investigated the effect of narrowband UV-B phototherapy (5 times per week) in 10 patients with cutaneous GVHD (grade 2-3) resistant to standard immunosuppressive drugs. It was tolerated well by all patients, and no side effects were observed. Skin lesions showed complete clearance in 7 out of 10 patients within 3 to 5 weeks. 3 patients showed significant improvement of GVHD. We suggest that narrowband UV-B phototherapy is a nonaggressive treatment that may benefit patients with cutaneous GVHD who already take high doses of immunosuppressive drugs.

[Effect of flavin adenine dinucleotide on ultraviolet B induced damage in cultured human corneal epithelial cells].

PubMed

Sakamoto, Asuka; Nakamura, Masatsugu

2012-01-01

This study evaluated the effects of flavin adenine dinucleotide (FAD) on ultraviolet B (UV-B)-induced damage in cultured human corneal epithelial (HCE-T) cells. The cultured HCE-T cells were treated with 0.003125-0.05% FAD before exposure to 80 mJ/cm2 UV-B. Cell viability was measured 24 h after UV-B irradiation using the MTS assay. Reactive oxygen species (ROS) were detected 30 min after UV-B irradiation using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester. Apoptosis was evaluated 4 h after UV-B irradiation in the caspase-3/7 activity assay. UV-B irradiation reduced cell viability and stimulated ROS production and caspase-3/7 activity in HCE-T cells. Pretreatment of UV-B irradiated HCE-T cells with FAD significantly attenuated cell viability reduction and inhibited the stimulation of both ROS production and caspase-3/7 activity due to UV-B exposure compared with those with vehicle (0% FAD). These results clarified that FAD inhibits ROS-mediated apoptosis by UV-B irradiation in HCE-T cells and suggest that FAD may be effective as a radical scavenger in UV-B-induced corneal damage.

Riboflavin induces Metarhizium spp. to produce conidia with elevated tolerance to UV-B, and upregulates photolyases, laccases and polyketide synthases genes.

PubMed

Pereira-Junior, R A; Huarte-Bonnet, C; Paixão, F R S; Roberts, D W; Luz, C; Pedrini, N; Fernandes, É K K

2018-02-23

The effect of nutritional supplementation of two Metarhizium species with riboflavin (Rb) during production of conidia was evaluated on (i) conidial tolerance (based on germination) to UV-B radiation and on (ii) conidial expression following UV-B irradiation, of enzymes known to be active in photoreactivation, viz., photolyase (Phr), laccase (Lac) and polyketide synthase (Pks). Metarhizium acridum (ARSEF 324) and Metarhizium robertsii (ARSEF 2575) were grown either on (i) potato dextrose agar medium (PDA), (ii) PDA supplemented with 1% yeast extract (PDAY), (iii) PDA supplemented with Rb (PDA+Rb), or (iv) PDAY supplemented with Rb (PDAY+Rb). Resulting conidia were exposed to 866·7 mW m -2 of UV-B Quaite-weighted irradiance to total doses of 3·9 or 6·24 kJ m -2 . Some conidia also were exposed to 16 klux of white light (WL) after being irradiated, or not, with UV-B to investigate the role of possible photoreactivation. Relative germination of conidia produced on PDA+Rb (regardless Rb concentration) or on PDAY and exposed to UV-B was higher compared to conidia cultivated on PDA without Rb supplement, or to conidia suspended in Rb solution immediately prior to UV-B exposure. The expression of MaLac3 and MaPks2 for M. acridum, as well as MrPhr2, MrLac1, MrLac2 and MrLac3 for M. robertsii was higher when the isolates were cultivated on PDA+Rb and exposed to UV-B followed by exposure to WL, or exposed to WL only. Rb in culture medium increases the UV-B tolerance of M. robertsii and M. acridum conidia, and which may be related to increased expression of Phr, Lac and Pks genes in these conidia. The enhanced UV-B tolerance of Metarhizium spp. conidia produced on Rb-enriched media may improve the effectiveness of these fungi in biological control programs. © 2018 The Society for Applied Microbiology.

Impact effects of gamma irradiation on the optical and FT infrared absorption spectra of some Nd3+-doped soda lime phosphate glasses

NASA Astrophysics Data System (ADS)

Marzouk, M. A.; Elkashef, I. M.; Elbatal, H. A.

2018-04-01

The main aim of the present work is to study by two collective optical and FTIR spectral measurements some prepared Nd2O3-doped soda lime phosphate glasses before and after gamma irradiation with dose (9 Mrad). The spectral data reveal two strong UV absorption peaks which are correlated with unavoidable trace iron impurities beside extended additional characteristic bands due to Nd3+ ions. Gamma irradiation on the undoped glass produces slight decrease of the intensity of the UV absorption and the generation of an induced visible band and these effects are controlled with two photochemical reduction of some Fe3+ ions to Fe2+ ions together with the formation of nonbridging oxygen hole center (NBOHC) or phosphorous oxygen hole center (POHC). The impact effect of gamma irradiation on the spectra of Nd2O3-doped glasses is limited due to suggested shielding behavior of neodymium ions. FT-infrared spectra show vibrational modes due to main Q2-Q3 phosphate groups and the response of gamma irradiation of the IR spectra is low and the limited variations are related to suggested changes in some bond angles and bond lengths which cause the observed decrease to the intensities of some IR bands.

Emulsifying and foaming properties of ultraviolet-irradiated egg white protein and sodium caseinate.

PubMed

Kuan, Yau-Hoong; Bhat, Rajeev; Karim, Alias A

2011-04-27

The physicochemical and functional properties of ultraviolet (UV)-treated egg white protein (EW) and sodium caseinate (SC) were investigated. UV irradiation of the proteins was carried out for 30, 60, 90, and 120 min. However, the SC samples were subjected to extended UV irradiation for 4 and 6 h as no difference was found on the initial UV exposure time. Formol titration, SDS-PAGE, and FTIR analyses indicated that UV irradiation could induce cross-linking on proteins and led to improved emulsifying and foaming properties (P < 0.05). These results indicated that the UV-irradiated EW and SC could be used as novel emulsifier and foaming agents in broad food systems for stabilizing and foaming purposes.

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

Characterization by combined optical and FT infrared spectra of 3d-transition metal ions doped-bismuth silicate glasses and effects of gamma irradiation.

PubMed

ElBatal, F H; Abdelghany, A M; ElBatal, H A

2014-03-25

Optical and infrared absorption spectral measurements were carried out for binary bismuth silicate glass and other derived prepared samples with the same composition and containing additional 0.2% of one of 3d transition metal oxides. The same combined spectroscopic properties were also measured after subjecting the prepared glasses to a gamma dose of 8 Mrad. The experimental optical spectra reveal strong UV-near visible absorption bands from the base and extended to all TMs-doped samples and these specific extended and strong UV-near visible absorption bands are related to the contributions of absorption from both trace iron (Fe(3+)) ions present as contaminated impurities within the raw materials and from absorption of main constituent trivalent bismuth (Bi(3+)) ions. The strong UV-near visible absorption bands are observed to suppress any further UV bands from TM ions. The studied glasses show obvious resistant to gamma irradiation and only small changes are observed upon gamma irradiation. This observed shielding behavior is related to the presence of high Bi(3+) ions with heavy mass causing the observed stability of the optical absorption. Infrared absorption spectra of the studied glasses reveal characteristic vibrational bands due to both modes from silicate network and the sharing of Bi-O linkages and the presence of TMs in the doping level (0.2%) causes no distinct changes within the number or position of the vibrational modes. The presence of high Bi2O3 content (70 mol%) appears to cause stability of the structural building units towards gamma irradiation as revealed by FTIR measurements. Copyright © 2013 Elsevier B.V. All rights reserved.

Protective Effect of Garlic on Cellular Senescence in UVB-Exposed HaCaT Human Keratinocytes.

PubMed

Kim, Hye Kyung

2016-07-29

Ultraviolet (UV) irradiation generates reactive oxygen species (ROS) in the cells, which induces the cellular senescence and photoaging. The present study investigated the protective effects of garlic on photo-damage and cellular senescence in UVB-exposed human keratinocytes, HaCaT cells. An in vitro cell free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and nitric oxide (NO). The effect of garlic extract on ROS formation, MMP-1 protein and mRNA expressions, cytokines such as interleukin (IL)-1β and IL-6, senescence associated-β-galactosidase (SA-β-gal) activity, and silent information regulator T1 (SIRT1) activity were determined in UVB-irradiated HaCaT cells. Garlic exhibited strong DPPH radical and NO scavenging activity in cell free system exhibiting IC50 values of 2.50 mg/mL and 4.38 mg/mL, respectively. Garlic pretreatment attenuated the production of UVB-induced intracellular ROS. MMP-1 level, which has been known to be induced by ROS, was dramatically elevated by UVB irradiation, and UVB-induced MMP-1 mRNA and protein expressions were significantly reduced by garlic treatment (50 µg/mL) comparable to those of UV-unexposed control cells. UV-induced pro-inflammatory cytokine productions (IL-6 and IL-1β) were significantly inhibited by pretreatment with garlic in a dose-dependent manner. SA-β-gal activity, a classical biomarker of cellular senescence, and SIRT1 activity, which has attracted attention as an anti-aging factor in recent years, were ameliorated by garlic treatment in UV-irradiated HaCaT cells. The present study provides the first evidence of garlic inhibiting UVB-induced photoaging as a result of augmentation of cellular senescence in HaCaT human keratinocytes.

Protective Effect of Garlic on Cellular Senescence in UVB-Exposed HaCaT Human Keratinocytes

PubMed Central

Kim, Hye Kyung

2016-01-01

Ultraviolet (UV) irradiation generates reactive oxygen species (ROS) in the cells, which induces the cellular senescence and photoaging. The present study investigated the protective effects of garlic on photo-damage and cellular senescence in UVB-exposed human keratinocytes, HaCaT cells. An in vitro cell free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and nitric oxide (NO). The effect of garlic extract on ROS formation, MMP-1 protein and mRNA expressions, cytokines such as interleukin (IL)-1β and IL-6, senescence associated-β-galactosidase (SA-β-gal) activity, and silent information regulator T1 (SIRT1) activity were determined in UVB-irradiated HaCaT cells. Garlic exhibited strong DPPH radical and NO scavenging activity in cell free system exhibiting IC50 values of 2.50 mg/mL and 4.38 mg/mL, respectively. Garlic pretreatment attenuated the production of UVB-induced intracellular ROS. MMP-1 level, which has been known to be induced by ROS, was dramatically elevated by UVB irradiation, and UVB-induced MMP-1 mRNA and protein expressions were significantly reduced by garlic treatment (50 µg/mL) comparable to those of UV-unexposed control cells. UV-induced pro-inflammatory cytokine productions (IL-6 and IL-1β) were significantly inhibited by pretreatment with garlic in a dose-dependent manner. SA-β-gal activity, a classical biomarker of cellular senescence, and SIRT1 activity, which has attracted attention as an anti-aging factor in recent years, were ameliorated by garlic treatment in UV-irradiated HaCaT cells. The present study provides the first evidence of garlic inhibiting UVB-induced photoaging as a result of augmentation of cellular senescence in HaCaT human keratinocytes. PMID:27483310

UV Irradiation of Skin Enhances Glycolytic Flux and Reduces Migration Capabilities in Bone Marrow-Differentiated Dendritic Cells.

PubMed

McGonigle, Terence A; Keane, Kevin N; Ghaly, Simon; Carter, Kim W; Anderson, Denise; Scott, Naomi M; Goodridge, Helen S; Dwyer, Amy; Greenland, Eloise; Pixley, Fiona J; Newsholme, Philip; Hart, Prue H

2017-09-01

A systemic immunosuppression follows UV irradiation of the skin of humans and mice. In this study, dendritic cells (DCs) differentiating from the bone marrow (BM) of UV-irradiated mice had a reduced ability to migrate toward the chemokine (C-C motif) ligand 21. Fewer DCs also accumulated in the peritoneal cavity of UV-chimeric mice (ie, mice transplanted with BM from UV-irradiated mice) after injection of an inflammatory stimulus into that site. We hypothesized that different metabolic states underpin altered DC motility. Compared with DCs from the BM of nonirradiated mice, those from UV-irradiated mice produced more lactate, consumed more glucose, and had greater glycolytic flux in a bioenergetics stress test. Greater expression of 3-hydroxyanthranilate 3,4-dioxygenase was identified as a potential contributor to increased glycolysis. Inhibition of 3-hydroxyanthranilate 3,4-dioxygenase by 6-chloro-dl-tryptophan prevented both increased lactate production and reduced migration toward chemokine (C-C motif) ligand 21 by DCs differentiated from BM of UV-irradiated mice. UV-induced prostaglandin E 2 has been implicated as an intermediary in the effects of UV radiation on BM cells. DCs differentiating from BM cells pulsed in vitro for 2 hours with dimethyl prostaglandin E 2 were functionally similar to those from the BM of UV-irradiated mice. Reduced migration of DCs to lymph nodes associated with increased glycolytic flux may contribute to their reduced ability to initiate new immune responses in UV-irradiated mice. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Factors affecting UV/H2O2 inactivation of Bacillus atrophaeus spores in drinking water.

PubMed

Zhang, Yongji; Zhang, Yiqing; Zhou, Lingling; Tan, Chaoqun

2014-05-05

This study aims at estimating the performance of the Bacillus atrophaeus spores inactivation by the UV treatment with addition of H2O2. The effect of factors affecting the inactivation was investigated, including initial H2O2 dose, UV irradiance, initial cell density, initial solution pH and various inorganic anions. Under the experimental conditions, the B. atrophaeus spores inactivation followed both the modified Hom Model and the Chick's Model. The results revealed that the H2O2 played dual roles in the reactions, while the optimum reduction of 5.88lg was received at 0.5mM H2O2 for 10min. The inactivation effect was affected by the UV irradiance, while better inactivation effect was achieved at higher irradiance. An increase in the initial cell density slowed down the inactivation process. A slight acid condition at pH 5 was considered as the optimal pH value. The inactivation effect within 10min followed the order of pH 5>pH 7>pH 9>pH 3>pH 11. The effects of three added inorganic anions were investigated and compared, including sulfate (SO4(2)(-)), nitrate (NO3(-)) and carbonate (CO3(2)(-)). The sequence of inactivation effect within 10min followed the order of control group>SO4(2)(-)>NO3(-)>CO3(2)(-). Copyright © 2014 Elsevier B.V. All rights reserved.

Relationship Between Radiation Response and the Deoxyribonucleic Acid Replication Cycle in Bacteria: Dependence on the Excision-Repair System

PubMed Central

Billen, Daniel; Bruns, Laura

1970-01-01

Prestarvation of Escherichia coli for required amino acids results in a marked enhancement in both ultraviolet light (UV) or X-ray resistance for selective strains. Preventing protein synthesis by starvation for required amino acids results in completion of the cycle of chromosomal replication then underway. We have investigated the relationship between starvation-induced resistance enhancement (SIRE) and the excision-repair (Hcr) system in several E. coli strains including E. coli B/r hcr+ and its isogenic mutant E. coli B/r hcr−. The following observations were made. (i) The Hcr system is the major component of SIRE in UV-irradiated strain B/r. By using the Hcr+ strain, SIRE increases the 10% survival dose from ∼400 ergs to ∼1,200 ergs/mm2. With the Hcr cells, the increase is from ∼45 ergs to 60 ergs/mm2. (ii) Although prestarvation leads to a moderate enhancement of resistance to X irradiation, this effect is not dependent on the Hcr system. (iii) The double mutant, E. coli Bs–1 (hcr−exr−) is completely unable to express SIRE whether studied with UV or X irradiation. It is concluded that the Hcr system is the major system responsible for SIRE in UV-treated cells, whereas Exr (resistance to X rays) may be involved to a minor extent. The Exr character appears to be required for SIRE expression in X-ray exposed cells. PMID:4914566

2016 Arte Poster Competition First Place Winner: Circadian Rhythm and UV-Induced Skin Damage: An In Vivo Study.

PubMed

Guan, Linna; Suggs, Amanda; Ahsanuddin, Sayeeda; Tarrillion, Madeline; Selph, Jacqueline; Lam, Minh; Baron, Elma

2016-09-01

Exposure of the skin to ultraviolet (UV) irradiation causes many detrimental effects through mechanisms related to oxidative stress and DNA damage. Excessive oxidative stress can cause apoptosis and cellular dysfunction of epidermal cells leading to cellular senescence and connective tissue degradation. Direct and indirect damage to DNA predisposes the skin to cancer formation. Chronic UV exposure also leads to skin aging manifested as wrinkling, loss of skin tone, and decreased resilience. Fortunately, human skin has several natural mechanisms for combating UV-induced damage. The mechanisms operate on a diurnal rhythm, a cycle that repeats approximately every 24 hours. It is known that the circadian rhythm is involved in many skin physiologic processes, including water regulation and epidermal stem cell function. This study evaluated whether UV damage and the skin's natural mechanisms of inflammation and repair are also affected by circadian rhythm. We looked at UV-induced erythema on seven human subjects irradiated with simulated solar radiation in the morning (at 08:00 h) versus in the afternoon (at 16:00 h). Our data suggest that the same dose of UV radiation induces significantly more inflammation in the morning than in the afternoon. Changes in protein expression relevant to DNA damage, such as xeroderma pigmentosum, complementation group A (XPA), and cyclobutane pyrimidine dimers (CPD) from skin biopsies correlated with our clinical results. Both XPA and CPD levels were higher after the morning UV exposure compared with the afternoon exposure.

J Drugs Dermatol. 2016;15(9):1124-1130.

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

NASA Astrophysics Data System (ADS)

Ranjan, Sukrit; Wordsworth, Robin; Sasselov, Dimitar D.

2017-07-01

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UV environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.

Determining optimum wavelength of ultraviolet rays to pre-exposure of non-uniformity error correction in Gafchromic EBT2 films

NASA Astrophysics Data System (ADS)

Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Noguchi, Atsushi; Yabunaka, Kouichi

2018-03-01

Gafchromic films have been used to measure X-ray doses in diagnostic radiology such as computed tomography. The double-exposure technique is used to correct non-uniformity error of Gafchromic EBT2 films. Because of the heel effect of diagnostic x-rays, ultraviolet A (UV-A) is intended to be used as a substitute for x-rays. When using a UV-A light-emitting diode (LED), it is necessary to determine the effective optimal UV wavelength for the active layer of Gafchromic EBT2 films. This study evaluated the relation between the increase in color density of Gafchromic EBT2 films and the UV wavelengths. First, to correct non-uniformity, a Gafchromic EBT2 film was pre-irradiated using uniform UV-A radiation for 60 min from a 72-cm distance. Second, the film was irradiated using a UV-LED with a wavelength of 353-410 nm for 60 min from a 5.3-cm distance. The maximum, minimum, and mean ± standard deviation (SD) of pixel values of the subtraction images were evaluated using 0.5 inches of a circular region of interest (ROI). The highest mean ± SD (8915.25 ± 608.86) of the pixel value was obtained at a wavelength of 375 nm. The results indicated that 375 nm is the most effective and sensitive wavelength of UV-A for Gafchromic EBT2 films and that UV-A can be used as a substitute for x-rays in the double-exposure technique.

Rad51 recombinase prevents Mre11 nuclease-dependent degradation and excessive PrimPol-mediated elongation of nascent DNA after UV irradiation

PubMed Central

Vallerga, María Belén; Mansilla, Sabrina F.; Federico, María Belén; Bertolin, Agustina P.; Gottifredi, Vanesa

2015-01-01

After UV irradiation, DNA polymerases specialized in translesion DNA synthesis (TLS) aid DNA replication. However, it is unclear whether other mechanisms also facilitate the elongation of UV-damaged DNA. We wondered if Rad51 recombinase (Rad51), a factor that escorts replication forks, aids replication across UV lesions. We found that depletion of Rad51 impairs S-phase progression and increases cell death after UV irradiation. Interestingly, Rad51 and the TLS polymerase polη modulate the elongation of nascent DNA in different ways, suggesting that DNA elongation after UV irradiation does not exclusively rely on TLS events. In particular, Rad51 protects the DNA synthesized immediately before UV irradiation from degradation and avoids excessive elongation of nascent DNA after UV irradiation. In Rad51-depleted samples, the degradation of DNA was limited to the first minutes after UV irradiation and required the exonuclease activity of the double strand break repair nuclease (Mre11). The persistent dysregulation of nascent DNA elongation after Rad51 knockdown required Mre11, but not its exonuclease activity, and PrimPol, a DNA polymerase with primase activity. By showing a crucial contribution of Rad51 to the synthesis of nascent DNA, our results reveal an unanticipated complexity in the regulation of DNA elongation across UV-damaged templates. PMID:26627254

Effect of UV-A and UV-B irradiation on the metabolic profile of aqueous humor in rabbits analyzed by 1H NMR spectroscopy.

PubMed

Tessem, May-Britt; Bathen, Tone F; Cejková, Jitka; Midelfart, Anna

2005-03-01

This study was conducted to investigate metabolic changes in aqueous humor from rabbit eyes exposed to either UV-A or -B radiation, by using (1)H nuclear magnetic resonance (NMR) spectroscopy and unsupervised pattern recognition methods. Both eyes of adult albino rabbits were irradiated with UV-A (366 nm, 0.589 J/cm(2)) or UV-B (312 nm, 1.667 J/cm(2)) radiation for 8 minutes, once a day for 5 days. Three days after the last irradiation, samples of aqueous humor were aspirated, and the metabolic profiles analyzed with (1)H NMR spectroscopy. The metabolic concentrations in the exposed and control materials were statistically analyzed and compared, with multivariate methods and one-way ANOVA. UV-B radiation caused statistically significant alterations of betaine, glucose, ascorbate, valine, isoleucine, and formate in the rabbit aqueous humor. By using principal component analysis, the UV-B-irradiated samples were clearly separated from the UV-A-irradiated samples and the control group. No significant metabolic changes were detected in UV-A-irradiated samples. This study demonstrates the potential of using unsupervised pattern recognition methods to extract valuable metabolic information from complex (1)H NMR spectra. UV-B irradiation of rabbit eyes led to significant metabolic changes in the aqueous humor detected 3 days after the last exposure.

Factors affecting color strength of printing on film-coated tablets by UV laser irradiation: TiO2 particle size, crystal structure, or concentration in the film, and the irradiated UV laser power.

PubMed

Hosokawa, Akihiro; Kato, Yoshiteru

2011-08-01

The purpose of this article is to study factors affecting color strength of printing on film-coated tablets by ultraviolet (UV) laser irradiation: particle size, crystal structure, or concentration of titanium dioxide (TiO2) in film, and irradiated UV laser power. Hydroxypropylmethylcellulose films containing 4.0% of TiO2, of which BET particle sizes were ranging from 126.1 to 219.8 nm, were irradiated 3.14W of UV laser at a wavelength 355 nm to study effects of TiO2 particle size and crystal structure on the printing. The films containing TiO2 concentration ranging from 1.0 to 7.7% were irradiated 3.14 or 5.39W of the UV laser to study effect of TiO2 concentration on the printing. The film containing 4.0% of TiO2, was irradiated the UV laser up to 6.42W to study effect of the UV laser power on the printing. The color strength of the printed films was estimated by a spectrophotometer as total color difference (dE). Particle size, crystal structure, and concentration of TiO2 in the films did not affect the printing. In the relationship between the irradiated UV laser power and dE, there found an inflection point (1.6W). When the UV laser power was below 1.6W, the films were not printed. When it was beyond the point, total color difference increased linearly in proportion with the irradiated laser power. The color strength of the printing on film was not changed by TiO2 particle size, crystal structure, and concentration, but could be controlled by regulating the irradiated UV laser power beyond the inflection point.

Preservation of Biomarkers from Cyanobacteria Mixed with Mars-Like Regolith Under Simulated Martian Atmosphere and UV Flux.

PubMed

Baqué, Mickael; Verseux, Cyprien; Böttger, Ute; Rabbow, Elke; de Vera, Jean-Pierre Paul; Billi, Daniela

2016-06-01

The space mission EXPOSE-R2 launched on the 24th of July 2014 to the International Space Station is carrying the BIOMEX (BIOlogy and Mars EXperiment) experiment aimed at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions. In order to prepare the analyses of the returned samples, ground-based simulations were carried out in Planetary and Space Simulation facilities. During the ground-based simulations, Chroococcidiopsis cells mixed with two Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) were exposed to a Martian simulated atmosphere combined or not with UV irradiation corresponding to the dose received during a 1-year-exposure in low Earth orbit (or half a Martian year on Mars). Cell survival and preservation of potential biomarkers such as photosynthetic and photoprotective pigments or DNA were assessed by colony forming ability assays, confocal laser scanning microscopy, Raman spectroscopy and PCR-based assays. DNA and photoprotective pigments (carotenoids) were detectable after simulations of the space mission (570 MJ/m(2) of UV 200-400 nm irradiation and Martian simulated atmosphere), even though signals were attenuated by the treatment. The fluorescence signal from photosynthetic pigments was differently preserved after UV irradiation, depending on the thickness of the samples. UV irradiation caused a high background fluorescence of the Martian mineral analogues, as revealed by Raman spectroscopy. Further investigation will be needed to ensure unambiguous identification and operations of future Mars missions. However, a 3-month exposure to a Martian simulated atmosphere showed no significant damaging effect on the tested cyanobacterial biosignatures, pointing out the relevance of the latter for future investigations after the EXPOSE-R2 mission. Data gathered during the ground-based simulations will contribute to interpret results from space experiments and guide our search for life on Mars.

Preservation of Biomarkers from Cyanobacteria Mixed with Mars­Like Regolith Under Simulated Martian Atmosphere and UV Flux

NASA Astrophysics Data System (ADS)

Baqué, Mickael; Verseux, Cyprien; Böttger, Ute; Rabbow, Elke; de Vera, Jean-Pierre Paul; Billi, Daniela

2016-06-01

The space mission EXPOSE-R2 launched on the 24th of July 2014 to the International Space Station is carrying the BIOMEX (BIOlogy and Mars EXperiment) experiment aimed at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions. In order to prepare the analyses of the returned samples, ground-based simulations were carried out in Planetary and Space Simulation facilities. During the ground-based simulations, Chroococcidiopsis cells mixed with two Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) were exposed to a Martian simulated atmosphere combined or not with UV irradiation corresponding to the dose received during a 1-year-exposure in low Earth orbit (or half a Martian year on Mars). Cell survival and preservation of potential biomarkers such as photosynthetic and photoprotective pigments or DNA were assessed by colony forming ability assays, confocal laser scanning microscopy, Raman spectroscopy and PCR-based assays. DNA and photoprotective pigments (carotenoids) were detectable after simulations of the space mission (570 MJ/m2 of UV 200-400 nm irradiation and Martian simulated atmosphere), even though signals were attenuated by the treatment. The fluorescence signal from photosynthetic pigments was differently preserved after UV irradiation, depending on the thickness of the samples. UV irradiation caused a high background fluorescence of the Martian mineral analogues, as revealed by Raman spectroscopy. Further investigation will be needed to ensure unambiguous identification and operations of future Mars missions. However, a 3-month exposure to a Martian simulated atmosphere showed no significant damaging effect on the tested cyanobacterial biosignatures, pointing out the relevance of the latter for future investigations after the EXPOSE-R2 mission. Data gathered during the ground-based simulations will contribute to interpret results from space experiments and guide our search for life on Mars.

Time-resolved optically stimulated luminescence of Al2O3:C for ion beam therapy dosimetry

NASA Astrophysics Data System (ADS)

Yukihara, Eduardo G.; Doull, Brandon A.; Ahmed, Md; Brons, Stephan; Tessonnier, Thomas; Jäkel, Oliver; Greilich, Steffen

2015-09-01

The objective of this study was to characterize the time-resolved (TR) optically stimulated luminescence (OSL) from Al2O3:C detectors and investigate methodologies to improve the accuracy of these detectors in ion beam therapy dosimetry, addressing the reduction in relative response to high linear energy transfer (LET) particles common to solid-state detectors. Al2O3:C OSL detectors (OSLDs) were exposed to proton, 4He, 12C and 16O beams in 22 particle/energy combinations and read using a custom-built TR-OSL reader. The OSL response {{r}\\text{OSL}} , relative to 60Co gamma dose to water, and the ratio between the UV and blue OSL emission bands of Al2O3:C (UV/blue ratio) were determined as a function of the LET. Monte-Carlo simulations with the multi-purpose interaction and transport code FLUKA were used to estimate the absorbed doses and particle energy spectra in the different irradiation conditions. The OSL responses {{r}\\text{OSL}} varied from 0.980 (0.73 keV μm-1) to 0.288 (120.8 keV μm-1). The OSL UV/blue ratio varied by a factor of two in the investigated LET range, but the variation for 12C beams was only 11%. OSLDs were also irradiated at different depths of carbon ion spread-out Bragg peaks (SOBPs), where it was shown that doses could be obtained with an accuracy of  ±2.0% at the entrance channel and within the SOBP using correction factors calculated based on the OSL responses obtained in this study. The UV/blue ratio did not allow accurate estimation of the dose-averaged LET for 12C SOBPs, although the values obtained can be explained with the data obtained in this study and the additional information provided by the Monte-Carlo simulations. The results demonstrate that accurate OSLD dosimetry can be performed in ion beam therapy using appropriate corrections for the OSL response.

Inactivation of antibiotic resistance genes in municipal wastewater by chlorination, ultraviolet, and ozonation disinfection.

PubMed

Zhuang, Yao; Ren, Hongqiang; Geng, Jinju; Zhang, Yingying; Zhang, Yan; Ding, Lili; Xu, Ke

2015-05-01

This study investigated the inactivation of two antibiotic resistance genes (ARGs)-sul1 and tetG, and the integrase gene of class 1 integrons-intI1 by chlorination, ultraviolet (UV), and ozonation disinfection. Inactivation of sul1, tetG, and intI1 underwent increased doses of three disinfectors, and chlorine disinfection achieved more inactivation of ARGs and intI1 genes (chlorine dose of 160 mg/L with contact time of 120 min for 2.98-3.24 log reductions of ARGs) than UV irradiation (UV dose of 12,477 mJ/cm(2) for 2.48-2.74 log reductions of ARGs) and ozonation disinfection (ozonation dose of 177.6 mg/L for 1.68-2.55 log reductions of ARGs). The 16S rDNA was more efficiently removed than ARGs by ozone disinfection. The relative abundance of selected genes (normalized to 16S rDNA) increased during ozonation and with low doses of UV and chlorine disinfection. Inactivation of sul1 and tetG showed strong positive correlations with the inactivation of intI1 genes (for sul1, R (2)  = 0.929 with p < 0.01; for tetG, R (2)  = 0.885 with p < 0.01). Compared to other technologies (ultraviolet disinfection, ozonation disinfection, Fenton oxidation, and coagulation), chlorination is an alternative method to remove ARGs from wastewater effluents. At a chlorine dose of 40 mg/L with 60 min contact time, the selected genes inactivation efficiency could reach 1.65-2.28 log, and the cost was estimated at 0.041 yuan/m(3).

Effect of Bifidobacterium breve B-3 on skin photoaging induced by chronic UV irradiation in mice.

PubMed

Satoh, T; Murata, M; Iwabuchi, N; Odamaki, T; Wakabayashi, H; Yamauchi, K; Abe, F; Xiao, J Z

2015-01-01

Probiotics have been shown to have a preventative effect on skin photoaging induced by short term UV irradiation, however, the underlying mechanisms and the effect of probiotics on skin photoaging induced by chronic UV irradiation remain unclear. In this study, we investigated the effect of Bifidobacterium breve B-3 on skin photoaging induced by chronic UV irradiation in hairless mice. Mice were irradiated with UVB three times weekly and orally administered B. breve B-3 (2×10(9) cfu/mouse /day) for 7 weeks. Nonirradiated mice and UVB-irradiated mice without probiotic treatment were used as controls. B. breve B-3 significantly suppressed the changes of transepidermal water loss, skin hydration, epidermal thickening and attenuated the damage to the tight junction structure and basement membrane induced by chronic UVB irradiation. Administration of B. breve B-3 tended to suppress the UV-induced interleukin-1β production in skin (P=0.09). These results suggest that B. breve B-3 could potentially be used to prevent photoaging induced by chronic UV irradiation.

Evolution of Morphological and Physical Properties of Laboratory Interstellar Organic Residues with Ultraviolet Irradiation

NASA Astrophysics Data System (ADS)

Piani, L.; Tachibana, S.; Hama, T.; Tanaka, H.; Endo, Y.; Sugawara, I.; Dessimoulie, L.; Kimura, Y.; Miyake, A.; Matsuno, J.; Tsuchiyama, A.; Fujita, K.; Nakatsubo, S.; Fukushi, H.; Mori, S.; Chigai, T.; Yurimoto, H.; Kouchi, A.

2017-03-01

Refractory organic compounds formed in molecular clouds are among the building blocks of the solar system objects and could be the precursors of organic matter found in primitive meteorites and cometary materials. However, little is known about the evolutionary pathways of molecular cloud organics from dense molecular clouds to planetary systems. In this study, we focus on the evolution of the morphological and viscoelastic properties of molecular cloud refractory organic matter. We found that the organic residue, experimentally synthesized at ˜10 K from UV-irradiated H2O-CH3OH-NH3 ice, changed significantly in terms of its nanometer- to micrometer-scale morphology and viscoelastic properties after UV irradiation at room temperature. The dose of this irradiation was equivalent to that experienced after short residence in diffuse clouds (≤104 years) or irradiation in outer protoplanetary disks. The irradiated organic residues became highly porous and more rigid and formed amorphous nanospherules. These nanospherules are morphologically similar to organic nanoglobules observed in the least-altered chondrites, chondritic porous interplanetary dust particles, and cometary samples, suggesting that irradiation of refractory organics could be a possible formation pathway for such nanoglobules. The storage modulus (elasticity) of photo-irradiated organic residues is ˜100 MPa irrespective of vibrational frequency, a value that is lower than the storage moduli of minerals and ice. Dust grains coated with such irradiated organics would therefore stick together efficiently, but growth to larger grains might be suppressed due to an increase in aggregate brittleness caused by the strong connections between grains.

Evolution of Morphological and Physical Properties of Laboratory Interstellar Organic Residues with Ultraviolet Irradiation

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

Piani, L.; Tachibana, S.; Endo, Y.

Refractory organic compounds formed in molecular clouds are among the building blocks of the solar system objects and could be the precursors of organic matter found in primitive meteorites and cometary materials. However, little is known about the evolutionary pathways of molecular cloud organics from dense molecular clouds to planetary systems. In this study, we focus on the evolution of the morphological and viscoelastic properties of molecular cloud refractory organic matter. We found that the organic residue, experimentally synthesized at ∼10 K from UV-irradiated H{sub 2}O-CH{sub 3}OH-NH{sub 3} ice, changed significantly in terms of its nanometer- to micrometer-scale morphology andmore » viscoelastic properties after UV irradiation at room temperature. The dose of this irradiation was equivalent to that experienced after short residence in diffuse clouds (≤10{sup 4} years) or irradiation in outer protoplanetary disks. The irradiated organic residues became highly porous and more rigid and formed amorphous nanospherules. These nanospherules are morphologically similar to organic nanoglobules observed in the least-altered chondrites, chondritic porous interplanetary dust particles, and cometary samples, suggesting that irradiation of refractory organics could be a possible formation pathway for such nanoglobules. The storage modulus (elasticity) of photo-irradiated organic residues is ∼100 MPa irrespective of vibrational frequency, a value that is lower than the storage moduli of minerals and ice. Dust grains coated with such irradiated organics would therefore stick together efficiently, but growth to larger grains might be suppressed due to an increase in aggregate brittleness caused by the strong connections between grains.« less

UV-associated decline in systemic folate: implications for human nutrigenetics, health, and evolutionary processes.

PubMed

Lucock, Mark; Beckett, Emma; Martin, Charlotte; Jones, Patrice; Furst, John; Yates, Zoe; Jablonski, Nina G; Chaplin, George; Veysey, Martin

2017-03-01

The purpose of this study was to examine whether UV exposure alters folate status according to C677T-MTHFR genotype, and to consider the relevance of this to human health and the evolutionary model of skin pigmentation. Total Ozone Mapping Spectrometer (TOMS) satellite data were used to examine surface UV-irradiance, as a marker of UV exposure, in a large (n = 649) Australian cross-sectional study population. PCR/RFLP analysis was used to genotype C677T-MTHFR. Overall, cumulative UV-irradiance (42 and 120 days pre-clinic) was significantly negatively related to red cell folate (RCF) levels. When the cohort was stratified by MTHFR-C677T genotype, the relationship between UV-irradiance (42 days pre-clinic) and RCF remained significant only in the cohorts containing carriers of the T allele. Statistically significant z-score statistics and interaction terms from genotype and UV-irradiance (p-interaction) demonstrated that genotype did modify the effect of UV-irradiance on RCF, with the largest effect of UV being demonstrated in the 677TT-MTHFR subjects. Data provide strong evidence that surface UV-irradiance reduces long-term systemic folate levels, and that this is influenced by the C677T-MTHFR gene variant. We speculate this effect may be due to 677TT-MTHFR individuals containing more 5,10CH 2 -H 4 PteGlu, and that this folate form may be particularly UV labile. Since UV-irradiance lowers RCF in an MTHFR genotype-specific way, there are likely implications for human health and the evolution of skin pigmentation. © 2016 Wiley Periodicals, Inc.

Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement.

PubMed

Reza, Fazal; Ibrahim, Nur Sukainah

2015-01-01

Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group.

Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement

PubMed Central

Reza, Fazal; Ibrahim, Nur Sukainah

2015-01-01

Objective: Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. Materials and Methods: A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). Results: SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Conclusions: Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group. PMID:25713488

Schistosoma japonicum: An ultraviolet-attenuated cercarial vaccine applicable in the field for water buffaloes

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

Shi, Y.E.; Jiang, C.F.; Han, J.J.

1990-07-01

Water buffaloes were vaccinated three times with 10,000 Schistosoma japonicum cercariae irradiated with ultraviolet (uv) light at a dose of 400 microW x min/cm2. The irradiation was performed with cheap, simple, and portable equipment in a rural area of Hubei Province (People's Republic of China). A challenge infection of 1000 untreated cercariae was given to six vaccinated and six naive control buffaloes, while two vaccinated animals were not challenged. The experiment was terminated 6 weeks after the challenge. Control animals had lost body weight and harbored a mean of 110 worms and 37 eggs per gram of liver. The vaccinatedmore » animals gained weight after the challenge and developed 89% resistance to infection with S. japonicum. Since schistosomiasis japonica is nowadays transmitted in China predominantly by domestic livestock, a uv-attenuated cercarial vaccine for bovines may contribute to the control of this disease.« less

UV irradiation to mouse skin decreases hippocampal neurogenesis and synaptic protein expression via HPA axis activation.

PubMed

Han, Mira; Ban, Jae-Jun; Bae, Jung-Soo; Shin, Chang-Yup; Lee, Dong Hun; Chung, Jin Ho

2017-11-14

The skin senses external environment, including ultraviolet light (UV). Hippocampus is a brain region that is responsible for memory and emotion. However, changes in hippocampus by UV irradiation to the skin have not been studied. In this study, after 2 weeks of UV irradiation to the mouse skin, we examined molecular changes related to cognitive functions in the hippocampus and activation of the hypothalamic-pituitary-adrenal (HPA) axis. UV exposure to the skin decreased doublecortin-positive immature neurons and synaptic proteins, including N-methyl-D-aspartate receptor 2 A and postsynaptic density protein-95, in the hippocampus. Moreover, we observed that UV irradiation to the skin down-regulated brain-derived neurotrophic factor expression and ERK signaling in the hippocampus, which are known to modulate neurogenesis and synaptic plasticity. The cutaneous and central HPA axes were activated by UV, which resulted in significant increases in serum levels of corticosterone. Subsequently, UV irradiation to the skin activated the glucocorticoid-signaling pathway in the hippocampal dentate gyrus. Interestingly, after 6 weeks of UV irradiation, mice showed depression-like behavior in the tail suspension test. Taken together, our data suggest that repeated UV exposure through the skin may negatively affect hippocampal neurogenesis and synaptic plasticity along with HPA axis activation.

Changes of minimal erythema dose after water and salt water baths.

PubMed

Gambichler, T; Schröpl, F

1998-01-01

Knowledge about the influence of salt water baths on UV irradiation, especially balneophototherapy, is incomplete. The aim of this study was to investigate the influence of various concentrated salt solutions on the minimal erythema dose (MED). We determined the MEDdry (UVB) in 24 healthy, previously UV unexposed subjects on the inner forearm. Subjects were divided randomly into two groups of 12. Subsequently, the MEDwet was assessed on each forearm after 30 min tap water or 5% salt water bath (group A), respectively, or after 30 min 10% or 20% salt water bath (group B), respectively. Compared with the MEDdry, a significantly decreased MEDwet, was observed after all exposures (group A==>F = 18.94; P < 0.001; group B==>F = 11.73; P < 0.006). A maximal relative decrease in MEDdry of about 51.4% was observed after the 10% salt water bath. The 5% salt solution caused a modest relative decrease in MEDwet of 23.4%. We observed a markedly increased photosensitivity to UVB after all exposures, without a linear correlation between the MED and the salt water concentration. A determination of MED during balneophototherapy should be carried out after bathing in order to reduce the cumulative UV dose and to prevent acute photodamage.

Ultraviolet Light (UV) Inactivation of Porcine Parvovirus in Liquid Plasma and Effect of UV Irradiated Spray Dried Porcine Plasma on Performance of Weaned Pigs

PubMed Central

Polo, Javier; Rodríguez, Carmen; Ródenas, Jesús; Russell, Louis E.; Campbell, Joy M.; Crenshaw, Joe D.; Torrallardona, David; Pujols, Joan

2015-01-01

A novel ultraviolet light irradiation (UV-C, 254 nm) process was designed as an additional safety feature for manufacturing of spray dried porcine plasma (SDPP). In Exp. 1, three 10-L batches of bovine plasma were inoculated with 105.2±0.12 tissue culture infectious dose 50 (TCID50) of porcine parvovirus (PPV) per mL of plasma and subjected to UV-C ranging from 0 to 9180 J/L. No viable PPV was detected in bovine plasma by micro-titer assay in SK6 cell culture after UV-C at 2295 J/L. In Exp. 2, porcine plasma was subjected to UV-C (3672 J/L), then spray dried and mixed in complete mash diets. Diets were a control without SDPP (Control), UV-C SDPP either at 3% (UVSDPP3) or 6% (UVSDPP6) and non-UV-C SDPP at 3% (SDPP3) or 6% (SDPP6). Diets were fed ad libitum to 320 weaned pigs (26 d of age; 16 pens/diet; 4 pigs/pen) for 14 d after weaning and a common diet was fed d 15 to 28. During d 0 to 14, pigs fed UVSDPP3, UVSDPP6, or SDPP6 had higher (P < 0.05) weight gain and feed intake than control. During d 0 to 28, pigs fed UVSDPP3 and UVSDPP6 had higher (P < 0.05) weight gain and feed intake than control and SDPP3, and SDPP6 had higher (P < 0.05) feed intake than control. Also, pigs fed UVSDPP had higher (P < 0.05) weight gain than pigs fed SDPP. In conclusion, UV-C inactivated PPV in liquid plasma and UVSDPP used in pig feed had no detrimental effects on pig performance. PMID:26171968

Electron beam assisted synthesis of silver nanoparticle in chitosan stabilizer: Preparation, stability and inhibition of building fungi studies

NASA Astrophysics Data System (ADS)

Jannoo, Kanokwan; Teerapatsakul, Churapa; Punyanut, Adisak; Pasanphan, Wanvimol

2015-07-01

Silver nanoparticles (AgNPs) in chitosan (CS) stabilizer were successfully synthesized using electron beam irradiation. The effects of irradiation dose, molecular weight (MW) of CS stabilizer, concentration of AgNO3 precursor and addition of tert-butanol on AgNPs production were studied. The stability of the AgNPs under different temperatures and storage times were also investigated. The AgNPs formation in CS was observed using UV-vis, FT-IR and XRD. The characteristic surface plasmon resonance (SPR) of the obtained AgNPs was around 418 nm. The CS stabilizer and its MW, AgNO3 precursor and irradiation doses are important parameters for the synthesis of AgNPs. The optimum addition of 20% v/v tert-butanol could assist the formation of AgNPs. The AgNPs in CS stabilizer were stable over a period of one year when the samples were kept at 5 °C. The AgNPs observed from TEM images were spherical with an average particle size in the range of 5-20 nm depending on the irradiation doses. The AgNPs in CS solution effectively inhibited the growth of several fungi, i.e., Curvularia lunata, Trichoderma sp., Penicillium sp. and Aspergillus niger, which commonly found on the building surface.

Melanin production through novel processing of proopiomelanocortin in the extracellular compartment of the auricular skin of C57BL/6 mice after UV-irradiation.

PubMed

Yamamoto, Hiroyuki; Yamane, Tomohiro; Iguchi, Kazuaki; Tanaka, Kiyotaka; Iddamalgoda, Arunasiri; Unno, Keiko; Hoshino, Minoru; Takeda, Atsushi

2015-09-29

The production of melanin is regulated by α-melanocyte-stimulating hormone (α-MSH), which is produced from proopiomelanocortin (POMC). Keratinocytes release POMC along with lower levels of α-MSH and ACTH. To clarify the mechanism of melanogenesis after ultraviolet (UV)-irradiation, this study focused on the expression of POMC and POMC-derived peptides after UV-irradiation. Western blot analysis and immunoassays indicated that both POMC and α-MSH-like immunoreactivity (α-MSH-LI) increased after UV-irradiation. However, other POMC-derived products were very low. In hypophysectomized mice, α-MSH-LI increased to the same level as in control mice after UV-irradiation. Structural analysis revealed that the major α-MSH-LI product was ACTH(1-8). Furthermore, ACTH(1-8) competed with [(125)I]-α-MSH for receptor binding and increased melanin production via a melanocortin-1 receptor. These results suggested that melanin was produced through ACTH(1-8) after UV-irradiation. Trypsin-like enzymatic activity, which is responsible for POMC activation, increased after UV-irradiation and was identified as tryptase. In mast cell-deficient mice, which do not produce tryptase, α-MSH-LI levels were unchanged after UV-irradiation. The present study demonstrates the production of ACTH(1-8) from POMC by tryptase, which is a novel peptide-processing mechanism in the extracellular compartment of the skin.

The Stress-responsive Gene ATF3 Mediates Dichotomous UV Responses by Regulating the Tip60 and p53 Proteins*

PubMed Central

Cui, Hongmei; Li, Xingyao; Han, Chunhua; Wang, Qi-En; Wang, Hongbo; Ding, Han-Fei; Zhang, Junran; Yan, Chunhong

2016-01-01

The response to UV irradiation is important for a cell to maintain its genetic integrity when challenged by environmental genotoxins. An immediate early response to UV irradiation is the rapid induction of activating transcription factor 3 (ATF3) expression. Although emerging evidence has linked ATF3 to stress pathways regulated by the tumor suppressor p53 and the histone acetyltransferase Tip60, the role of ATF3 in the UV response remains largely unclear. Here, we report that ATF3 mediated dichotomous UV responses. Although UV irradiation enhanced the binding of ATF3 to Tip60, knockdown of ATF3 expression decreased Tip60 stability, thereby impairing Tip60 induction by UV irradiation. In line with the role of Tip60 in mediating UV-induced apoptosis, ATF3 promoted the death of p53-defective cells in response to UV irradiation. However, ATF3 could also activate p53 and promote p53-mediated DNA repair, mainly through altering histone modifications that could facilitate recruitment of DNA repair proteins (such as DDB2) to damaged DNA sites. As a result, ATF3 rather protected the p53 wild-type cells from UV-induced apoptosis. Our results thus indicate that ATF3 regulates cell fates upon UV irradiation in a p53-dependent manner. PMID:26994140

Low dose ionizing radiation detection using conjugated polymers

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

Silva, E.A.B.; Borin, J.F.; Nicolucci, P.

2005-03-28

In this work, the effect of gamma radiation on the optical properties of poly[2-methoxy-5-(2{sup '}-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) is studied. The samples were irradiated at room temperature with different doses from 0 Gy to 152 Gy using a {sup 60}Co gamma ray source. For thin films, significant changes in the UV-visible spectra were only observed at high doses (>1 kGy). In solution, shifts in absorption peaks are observed at low doses (<10 Gy), linearly dependent on dose. The shifts are explained by conjugation reduction, and possible causes are discussed. Our results indicate that MEH-PPV solution can be used as a dosimeter adequatemore » for medical applications.« less

Microbial survival of space vacuum and extreme ultraviolet irradiation: strain isolation and analysis during a rocket flight.

PubMed

Saffary, Roya; Nandakumar, Renu; Spencer, Dennis; Robb, Frank T; Davila, Joseph M; Swartz, Marvin; Ofman, Leon; Thomas, Roger J; DiRuggiero, Jocelyne

2002-09-24

We have recovered new isolates from hot springs, in Yellowstone National Park and the Kamchatka Peninsula, after gamma-irradiation and exposure to high vacuum (10(-6) Pa) of the water and sediment samples. The resistance to desiccation and ionizing radiation of one of the isolates, Bacillus sp. strain PS3D, was compared to that of the mesophilic bacterium, Deinococcus radiodurans, a species well known for its extraordinary resistance to desiccation and high doses of ionizing radiation. Survival of these two microorganisms was determined in real and simulated space conditions, including exposure to extreme UV radiation (10-100 nm) during a rocket flight. We found that up to 15 days of desiccation alone had little effect on the viability of either bacterium. In contrast, exposure to space vacuum ( approximately 10(-6) Pa) decreased cell survival by two and four orders of magnitude for Bacillus sp. strain PS3D and D. radiodurans, respectively. Simultaneous exposure to space vacuum and extreme UV radiation further decreased the survival of both organisms, compared to unirradiated controls. This is the first report on the isolated effect of extreme UV at 30 nm on cell survival. Extreme UV can only be transmitted through high vacuum, therefore its penetration into the cells may only be superficial, suggesting that in contrast to near UV, membrane proteins rather than DNA were damaged by the radiation.

A comparative study of disinfection efficiency and regrowth control of microorganism in secondary wastewater effluent using UV, ozone, and ionizing irradiation process.

PubMed

Lee, O-Mi; Kim, Hyun Young; Park, Wooshin; Kim, Tae-Hun; Yu, Seungho

2015-09-15

Ionizing radiation technology was suggested as an alternative method to disinfection processes, such as chlorine, UV, and ozone. Although many studies have demonstrated the effectiveness of irradiation technology for microbial disinfection, there has been a lack of information on comparison studies of disinfection techniques and a regrowth of each treatment. In the present study, an ionizing radiation was investigated to inactivate microorganisms and to determine the critical dose to prevent the regrowth. As a result, it was observed that the disinfection efficiency using ionizing radiation was not affected by the seasonal changes of wastewater characteristics, such as temperature and turbidity. In terms of bacterial regrowth after disinfection, the ionizing radiation showed a significant resistance of regrowth, whereas, on-site UV treatment is influenced by the suspended solid, temperature, or precipitation. The electric power consumption was also compared for the economic feasibility of each technique at a given value of disinfection efficiency of 90% (1-log), showing 0.12, 36.80, and 96.53 Wh/(L/day) for ionizing radiation, ozone, and UV, respectively. The ionizing radiation requires two or three orders of magnitude lower power consumption than UV and ozone. Consequently, ionizing radiation can be applied as an effective and economical alternative technique to other conventional disinfection processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultraviolet radiation induces dose-dependent pigment dispersion in crustacean chromatophores.

PubMed

Gouveia, Glauce Ribeiro; Lopes, Thaís Martins; Neves, Carla Amorim; Nery, Luiz Eduardo Maia; Trindade, Gilma Santos

2004-10-01

Pigment dispersion in chromatophores as a response to UV radiation was investigated in two species of crustaceans, the crab Chasmagnathus granulata and the shrimp Palaemonetes argentinus. Eyestalkless crabs and shrimps maintained on either a black or a white background were irradiated with different UV bands. In eyestalkless crabs the significant minimal effective dose inducing pigment dispersion was 0.42 J/cm(2) for UVA and 2.15 J/cm(2) for UVB. Maximal response was achieved with 10.0 J/cm(2) UVA and 8.6 J/cm(2) UVB. UVA was more effective than UVB in inducing pigment dispersion. Soon after UV exposure, melanophores once again reached the initial stage of pigment aggregation after 45 min. Aggregated erythrophores of shrimps adapted to a white background showed significant pigment dispersion with 2.5 J/cm(2) UVA and 0.29 J/cm(2) UVC. Dispersed erythrophores of shrimps adapted to a black background did not show any significant response to UVA, UVB or UVC radiation. UVB did not induce any significant pigment dispersion in shrimps adapted to either a white or a black background. As opposed to the tanning response, which only protects against future UV exposure, the pigment dispersion response could be an important agent protecting against the harmful effects of UV radiation exposure.

Nitroxides are more efficient inhibitors of oxidative damage to calf skin collagen than antioxidant vitamins.

PubMed

Venditti, Elisabetta; Scirè, Andrea; Tanfani, Fabio; Greci, Lucedio; Damiani, Elisabetta

2008-01-01

Reactive oxygen species generated upon UV-A exposure appear to play a major role in dermal connective tissue transformations including degradation of skin collagen. Here we investigate on oxidative damage to collagen achieved by exposure to (i) UV-A irradiation and to (ii) AAPH-derived radicals and on its possible prevention using synthetic and natural antioxidants. Oxidative damage was identified through SDS-PAGE, circular dichroism spectroscopy and quantification of protein carbonyl residues. Collagen (2 mg/ml) exposed to UV-A and to AAPH-derived radicals was degraded in a time- and dose-dependent manner. Upon UV-A exposure, maximum damage was observable at 730 kJ/m2 UV-A, found to be equivalent to roughly 2 h of sunshine, while exposure to 5 mM AAPH for 2 h at 50 degrees C lead to maximum collagen degradation. In both cases, dose-dependent protection was achieved by incubation with muM concentrations of nitroxide radicals, where the extent of protection was shown to be dictated by their structural differences whereas the vitamins E and C proved less efficient inhibitors of collagen damage. These results suggest that nitroxide radicals may be able to prevent oxidative injury to dermal tissues in vivo alternatively to commonly used natural antioxidants.

Focal brain lesions induced with ultraviolet irradiation.

PubMed

Nakata, Mariko; Nagasaka, Kazuaki; Shimoda, Masayuki; Takashima, Ichiro; Yamamoto, Shinya

2018-05-22

Lesion and inactivation methods have played important roles in neuroscience studies. However, traditional techniques for creating a brain lesion are highly invasive, and control of lesion size and shape using these techniques is not easy. Here, we developed a novel method for creating a lesion on the cortical surface via 365 nm ultraviolet (UV) irradiation without breaking the dura mater. We demonstrated that 2.0 mWh UV irradiation, but not the same amount of non-UV light irradiation, induced an inverted bell-shaped lesion with neuronal loss and accumulation of glial cells. Moreover, the volume of the UV irradiation-induced lesion depended on the UV light exposure amount. We further succeeded in visualizing the lesioned site in a living animal using magnetic resonance imaging (MRI). Importantly, we also observed using an optical imaging technique that the spread of neural activation evoked by adjacent cortical stimulation disappeared only at the UV-irradiated site. In summary, UV irradiation can induce a focal brain lesion with a stable shape and size in a less invasive manner than traditional lesioning methods. This method is applicable to not only neuroscientific lesion experiments but also studies of the focal brain injury recovery process.

Effect of Ultraviolet Irradiation of the Implant Surface on Progression of Periimplantitis--A Pilot Study in Dogs.

PubMed

Ishii, Kouken; Matsuo, Masato; Hoshi, Noriyuki; Takahashi, Shun-Suke; Kawamata, Ryota; Kimoto, Katsuhiko

2016-02-01

The objective of this study was to investigate morphologically the progression of periimplantitis around an ultraviolet (UV)-light-irradiated implant in dogs. Pure titanium implants (3.3 mm in diameter and 8 mm long) were placed into dog jawbone bilaterally. Implants on one side were irradiated with UV light for 15 minutes using a photodevice immediately before placement (UV group), whereas those on the other side were not irradiated (non-UV group). Osseointegration was confirmed 90 days after implant placement by radiography. Experimental periimplantitis was induced by the application of dental floss over 90 days. Clinical and radiographic examination and micro-computed tomography (micro-CT) were performed after 90 and 180 days, and bone resorption was measured. The bone-implant interface in tissue sections was examined by light microscopy. Bone resorption around the UV-irradiated implant was less pronounced than around the non-UV-irradiated implant in the ligature-induced periimplantitis model. Tissue section images revealed no contact and partial destruction at the bone-implant interface. Within the limitations of this preliminary investigation, it is suggested that UV-light-irradiated implants suppress spontaneous progression of periimplantitis.

UV-B Irradiation Changes Specifically the Secondary Metabolite Profile in Broccoli Sprouts: Induced Signaling Overlaps with Defense Response to Biotic Stressors

PubMed Central

Mewis, Inga; Schreiner, Monika; Nguyen, Chau Nhi; Krumbein, Angelika; Ulrichs, Christian; Lohse, Marc; Zrenner, Rita

2012-01-01

Only a few environmental factors have such a pronounced effect on plant growth and development as ultraviolet light (UV). Concerns have arisen due to increased UV-B radiation reaching the Earth’s surface as a result of stratospheric ozone depletion. Ecologically relevant low to moderate UV-B doses (0.3–1 kJ m–2 d–1) were applied to sprouts of the important vegetable crop Brassica oleracea var. italica (broccoli), and eco-physiological responses such as accumulation of non-volatile secondary metabolites were related to transcriptional responses with Agilent One-Color Gene Expression Microarray analysis using the 2×204 k format Brassica microarray. UV-B radiation effects have usually been linked to increases in phenolic compounds. As expected, the flavonoids kaempferol and quercetin accumulated in broccoli sprouts (the aerial part of the seedlings) 24 h after UV-B treatment. A new finding is the specific UV-B-mediated induction of glucosinolates (GS), especially of 4-methylsulfinylbutyl GS and 4-methoxy-indol-3-ylmethyl GS, while carotenoids and Chl levels remained unaffected. Accumulation of defensive GS metabolites was accompanied by increased expression of genes associated with salicylate and jasmonic acid signaling defense pathways and up-regulation of genes responsive to fungal and bacterial pathogens. Concomitantly, plant pre-exposure to moderate UV-B doses had negative effects on the performance of the caterpillar Pieris brassicae (L.) and on the population growth of the aphid Myzus persicae (Sulzer). Moreover, insect-specific induction of GS in broccoli sprouts was affected by UV-B pre-treatment. PMID:22773681

Tuning the properties of tin oxide thin films for device fabrications

NASA Astrophysics Data System (ADS)

Sudha, A.; Sharma, S. L.; Gupta, A. N.; Sharma, S. D.

2017-11-01

Tin oxide thin films were deposited on well cleaned glass substrates by thermal evaporation in vacuum and were annealed at 500 ∘C in the open atmosphere inside a furnace for 90 min for promoting the sensitivity of the films. The X-ray diffraction studies revealed that the as-deposited films were amorphous in nature and the annealed films showed appreciable crystalline behavior. The annealed thin films were then irradiated using 60Co gamma source. The radiation induced changes were then studied by X-ray diffraction, scanning electron microscopy, UV-vis spectroscopy and I- V characterization. The remarkable increase in the average grain size, the decrement in the energy band gap and resistivity due to the gamma irradiations up to a certain dose and the reversal of these properties at higher doses are the important observations. The large changes in the conductivity and energy band gap of the annealed thin films due to gamma irradiation make these films quite important device material for the fabrication of gamma sensors and dosimeters.

Horizontal and sun-normal spectral biologically effective ultraviolet irradiances.

PubMed

Parisi, A V; Kimlin, M G

1999-01-01

The dependence of the spectral biologically effective solar UV irradiance on the orientation of the receiver with respect to the sun has been determined for relatively cloud-free days at a sub-tropical Southern Hemisphere latitude for the solar zenith angle range 35-64 degrees. For the UV and biologically effective irradiances, the sun-normal to horizontal ratio for the total UV ranges from 1.18 +/- 0.05 to 1.27 +/- 0.06. The sun-normal to horizontal ratio for biologically effective irradiance is dependent on the relative effectiveness of the relevant action spectrum in the UV-A waveband. In contrast to the total UV, the diffuse UV and diffuse biologically effective irradiances are reduced in a sun-normal compared with a horizontal orientation by a factor ranging from 0.70 +/- 0.05 to 0.76 +/- 0.03.

Photoreactivation in Paramecium tetraurelia under conditions of various degrees of ozone layer depletion.

PubMed

Takahashi, Akihisa; Kumatani, Toshihiro; Usui, Saori; Tsujimura, Ryoko; Seki, Takaharu; Morimoto, Kouichi; Ohnishi, Takeo

2005-01-01

Photoreactivation (PR) is an efficient survival mechanism that helps protect cells against the harmful effects of solar-ultraviolet (UV) radiation. The PR mechanism involves photolyase, just one enzyme, and can repair DNA damage, such as cyclobutane-pyrimidine dimers (CPD) induced by near-UV/blue light, a component of sunlight. Although the balance of near-UV/blue light and far-UV light reaching the Earth's surface could be altered by the atmospheric ozone layer's depletion, experiments simulating this environmental change and its possible effects on life have not yet been performed. To quantify the strength of UVB in sunlight reaching the Earth's surface, we measured the number of CPD generated in plasmid DNA after UVB irradiation or exposure to sunlight. To simulate the increase of solar-UV radiation resulting from the ozone layer depletion, Paramecium tetraurelia was exposed to UVB and/or sunlight in clear summer weather. PR recovery after exposure to sunlight was complete at a low dose rate of 0.2 J/m2 x s, but was less efficient when the dose rate was increased by a factor of 2.5 to 0.5 J/m2 x s. It is suggested that solar-UV radiation would not influence the cell growth of P. tetraurelia for the reason of high PR activity even when the ozone concentration was decreased 30% from the present levels.

Formation of iodinated trihalomethanes during UV/chloramination with iodate as the iodine source.

PubMed

Zhang, Tian-Yang; Lin, Yi-Li; Wang, An-Qi; Tian, Fu-Xiang; Xu, Bin; Xia, Sheng-Ji; Gao, Nai-Yun

2016-07-01

Iodinated trihalomethanes (I-THMs) are a group of emerging disinfection by-products with high toxicity, and iodide (I(-)) as well as iodinated organic compounds are expected to be their iodine sources. Nevertheless, in this study, iodate (IO3(-)) was proven to be a new iodine source of I-THM formation during UV/chloramination. In the iodate-containing waters (without any other iodine sources), I-THM formation increased with the increase of UV dose, IO3(-) and NH2Cl concentrations. With the increase of Br(-)/IO3(-) molar ratio, I-THM formation (especially for the brominated species) increased. Besides, NOM species could affect I-THM formation from IO3(-) during UV/chloramination. Fulvic acid could promote IO3(-) phototransformation to I(-) but humic acid impeded the production of I(-) during UV irradiation. Under realistic drinking water treatment conditions (DOC = 5.0 mg-C/L, IO3(-) = 12.7 μg-I/L, UV dose = 50 mJ/cm(2), NH2Cl = 5 mg-Cl2/L), CHCl2I was detected as 0.17 μg/L using solid-phase microextraction method, and the production rate of I-THMs from IO3(-) was about 7% of that from I(-). Copyright © 2016 Elsevier Ltd. All rights reserved.

Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens

PubMed Central

Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun

2015-01-01

Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm2. At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens. PMID:26162872

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

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

Ranjan, Sukrit; Sasselov, Dimitar D.; Wordsworth, Robin, E-mail: sranjan@cfa.harvard.edu

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UVmore » environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.« less

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

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

PubMed

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

2016-06-01

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

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

PubMed Central

Slieman, Tony A.; Nicholson, Wayne L.

2000-01-01

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

Effects of UV 254 irradiation on residual chlorine and DBPs in chlorination of model organic-N precursors in swimming pools.

PubMed

Weng, ShihChi; Li, Jing; Blatchley, Ernest R

2012-05-15

Ultraviolet (UV) irradiation is commonly applied as a secondary disinfection process in chlorinated pools. UV-based systems have been reported to yield improvements in swimming pool water and air chemistry, but to date these observations have been largely anecdotal. The objectives of this investigation were to evaluate the effects of UV irradiation on chlorination of important organic-N precursors in swimming pools. Creatinine, L-arginine, L-histidine, glycine, and urea, which comprise the majority of the organic-N in human sweat and urine, were selected as precursors for use in conducting batch experiments to examine the time-course behavior of several DBPs and residual chlorine, with and without UV(254) irradiation. In addition, water samples from two natatoria were subjected to monochromatic UV irradiation at wavelengths of 222 nm and 254 nm to evaluate changes of liquid-phase chemistry. UV(254) irradiation promoted formation and/or decay of several chlorinated N-DBPs and also increased the rate of free chlorine consumption. UV exposure resulted in loss of inorganic chloramines (e.g., NCl(3)) from solution. Dichloromethylamine (CH(3)NCl(2)) formation from creatinine was promoted by UV exposure, when free chlorine was present in solution; however, when free chlorine was depleted, CH(3)NCl(2) photodecay was observed. Dichloroacetonitrile (CNCHCl(2)) formation (from L-histidine and L-arginine) was promoted by UV(254) irradiation, as long as free chlorine was present in solution. Likewise, UV exposure was observed to amplify cyanogen chloride (CNCl) formation from chlorination of L-histidine, L-arginine, and glycine, up to the point of free chlorine depletion. The results from experiments involving UV irradiation of chlorinated swimming pool water were qualitatively consistent with the results of model experiments involving UV/chlorination of precursors in terms of the behavior of residual chlorine and DBPs measured in this study. The results indicate that UV(254) irradiation promotes several reactions that are involved in the formation and/or destruction of chlorinated N-DBPs in pool settings. Enhancement of DBP formation was consistent with a mechanism whereby a rate-limiting step in DBP formation was promoted by UV exposure. Promotion of these reactions also resulted in increases of free chlorine consumption rates. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Device performance and lifetime of polymer:fullerene solar cells with UV-ozone-irradiated hole-collecting buffer layers.

PubMed

Lee, Seungsoo; Nam, Sungho; Lee, Hyena; Kim, Hwajeong; Kim, Youngkyoo

2011-11-18

We report the influence of UV-ozone irradiation of the hole-collecting buffer layers on the performance and lifetime of polymer:fullerene solar cells. UV-ozone irradiation was targeted at the surface of the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layers by varying the irradiation time up to 600 s. The change of the surface characteristics in the PEDOT:PSS after UV-ozone irradiation was measured by employing optical absorption spectroscopy, photoelectron yield spectroscopy, and contact angle measurements, while Raman and X-ray photoelectron spectroscopy techniques were introduced for more microscopic analysis. Results showed that the UV-ozone irradiation changed the chemical structure/composition of the surface of the PEDOT:PSS layers leading to the gradual increase of ionization potential with irradiation time in the presence of up-and-down variations in the contact angle (polarity). This surface property change was attributed to the formation of oxidative components, as evidenced by XPS and Auger electron images, which affected the sheet resistance of the PEDOT:PSS layers. Interestingly, device performance was slightly improved by short irradiation (up to 10 s), whereas it was gradually decreased by further irradiation. The short-duration illumination test showed that the lifetime of solar cells with the UV-ozone irradiated PEDOT:PSS layer was improved due to the protective role of the oxidative components formed upon UV-ozone irradiation against the attack of sulfonic acid groups in the PEDOT:PSS layer to the active layer. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wild chrysanthemum extract prevents UVB radiation-induced acute cell death and photoaging.

PubMed

Sun, Sujiao; Jiang, Ping; Su, Weiting; Xiang, Yang; Li, Jian; Zeng, Lin; Yang, Shuangjuan

2016-03-01

Wild chrysanthemum (Chrysanthemum indicum L.) is traditionally used in folk medicine as an anti-inflammatory agent. It is also used in the southwest plateau region of China to prevent ultraviolet-induced skin damage. However, the role and mechanism by which wild chrysanthemum prevents UV-induced skin damage and photoaging have never been investigated in vitro. In the present study, we found that aqueous extracts from wild chrysanthemum strongly reduced high-dose UVB-induced acute cell death of human immortalized keratinocytic HaCat cells. Wild chrysanthemum extract was also demonstrated to reduce low-dose UVB-induced expression of the photoaging-related matrix metalloproteinases MMP-2 and MMP-9. The ROS level elevated by UVB irradiation was strongly attenuated by wild chrysanthemum extract. Further study revealed that wild chrysanthemum extract reduced UVB-triggered ERK1/2 and p38 MAPK phosphorylation and their protective role, which is partially dependent on inhibiting p38 activation. These results suggest that wild chrysanthemum extract can protect the skin from UVB-induced acute skin damage and photoaging by reducing the intracellular reactive oxygen species (ROS) level and inhibiting p38 MAPK phosphorylation. The present study confirmed the protective role of wild chrysanthemum against UV-induced skin disorders in vitro and indicated the possible mechanism. Further study to identify the active components in wild chrysanthemum extract would be useful for developing new drugs for preventing and treating skin diseases, including skin cancer and photoaging, induced by UV irradiation.

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)

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

Clark, E.

Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retainedmore » their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10°C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.« less

COMPARATIVE DISINFECTION EFFICIENCY OF PULSED AND CONTINUOUS-WAVE UV IRRADIATION TECHNOLOGIES

EPA Science Inventory

Pulsed UV (PUV) is novel UV irradiation system that is a non-mercury lamp based alternative to currently used continuous-wave systems for water disinfection. To compare the polychromatic PUV irradiation disinfection efficiency with that from continuous wave monochromatic low-pre...

Biological effects of high ultraviolet radiation on early earth--a theoretical evaluation.

PubMed

Cockell, C S

1998-08-21

The surface of early Earth was exposed to both UVC radiation (< 280 nm) and higher doses of UVB (280-315 nm) compared with the surface of present day Earth. The degree to which this radiation environment acted as a selection pressure on organisms and biological systems has rarely been theoretically examined with respect to the biologically effective irradiances that ancient organisms would receive. Here action spectra for DNA inactivation and isolated chloroplast inhibition are used to estimate biologically effective irradiances on archean Earth. Comparisons are made with present day Earth. The theoretical estimations on the UV radiation screening required to protect DNA on archean Earth compare well with field and laboratory observations on protection strategies found in present day microbial communities. They suggest that many physical and biological methods may have been effective and would have allowed for the radiation of life even under the high UV radiation regimes of archean Earth. Such strategies would also have provided effective reduction of photoinhibition by UV radiation. The data also suggest that the UV regime on the surface of Mars is not a life limiting factor per se, although other environmental factors such as desiccation and low temperatures may contribute towards the apparent lack of a surface biota.

Study the effect of gamma radiation pretreatment of sugarcane bagasse on its physcio-chemical morphological and structural properties

NASA Astrophysics Data System (ADS)

Kapoor, Khushboo; Garg, Neelima; Diwan, R. K.; Varshney, Lalit; Tyagi, Ajay K.

2017-12-01

Sugarcane bagasse was exposed to gamma radiation at different doses i.e. 100, 500, 1000 and 2000 kGy at a dose rate of 2.5 kGy/h and characterized for physical, chemical, morphological and structural properties. Results showed that on exposure of sugarcane bagasse, hemicellulose content reduced from 31% to 12.4% at 2000 kGy dose. The cellulose content of bagasse did not get affected much upto 1000 kGy exposure; however at 2000 kGy dose it decreased considerably. XRD study shows an initial increase in crystallinity index of bagasse at a dose level of 100 kGy while on further increase in radiation dose from 100 kGy to 2000 kGy the crystallinity index of bagasse decreases. Pores in the SEM photograph were observed on the surface of irradiated bagasse. UV-Vis spectra of bagasse showed a red shift indicating internal changes caused by radiation exposure. Study shows that the irradiation of bagasse results in disrupton of the lignocellulosic structure of Bagasse which opens up for easy accessibility of acids and hydrolytic enzymes for cellulosic hydrolysis resulting into fermentable sugars.

Low dose X -ray effects on catalase activity in animal tissue

NASA Astrophysics Data System (ADS)

Focea, R.; Nadejde, C.; Creanga, D.; Luchian, T.

2012-12-01

This study was intended to investigate the effect of low-dose X ray-irradiation upon the activity of catalase (CAT) in freshly excised chicken tissues (liver, kidney, brain, muscle). The tissue samples were irradiated with 0.5Gy and 2Gy respectively, in a 6 MV photon beam produced by a clinical linear accelerator (VARIAN CLINAC 2100SC). The dose rate was of 260.88cGy/min. at 100 cm source to sample distance. The catalase level was assayed spectrophotometrically, based on reaction kinetics, using a catalase UV assay kit (SIGMA). Catalase increased activity in various tissue samples exposed to the studied X ray doses (for example with 24 % in the liver cells, p<0.05) suggested the stimulation of the antioxidant enzyme biosynthesis within several hours after exposure at doses of 0.5 Gy and 2 Gy; the putative enzyme inactivation could also occur (due to the injuries on the hydrogen bonds that ensure the specificity of CAT active site) but the resulted balance of the two concurrent processes indicates the cell ability of decomposing the hydrogen peroxide-with benefits for the cell physiology restoration for the chosen low dose radiation.

Cloud cover and horizontal plane eye damaging solar UV exposures.

PubMed

Parisi, A V; Downs, N

2004-11-01

The spectral UV and the cloud cover were measured at intervals of 5 min with an integrated cloud and spectral UV measurement system at a sub-tropical Southern Hemisphere site for a 6-month period and solar zenith angle (SZA) range of 4.7 degrees to approximately 80 degrees . The solar UV spectra were recorded between 280 nm and 400 nm in 0.5 nm increments and weighted with the action spectra for photokeratitis and cataracts in order to investigate the effect of cloud cover on the horizontal plane biologically damaging UV irradiances for cataracts (UVBE(cat)) and photokeratitis (UVBE(pker)). Eighty five percent of the recorded spectra produced a measured irradiance to a cloud free irradiance ratio of 0.6 and higher while 76% produced a ratio of 0.8 and higher. Empirical non-linear expressions as a function of SZA have been developed for all sky conditions to allow the evaluation of the biologically damaging UV irradiances for photokeratitis and cataracts from a knowledge of the unweighted UV irradiances.

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

Betisheva, N.K.; Samoilova, K.A.

This paper studies the DNA-synthetic activity of hyman embryonic cells (EC) cultured in the presence of supernatants from intact and irradiated cell fractions of blood or plasma. Human EC obtained from abortion material were incubated; after incubation, tritium-thymidine was added to the growth medium for 30 min. It is shown that stimulation of DNA synthesis in EC growing in the presence of supernatants from irradiated whole blood is not connected with photoactivation of growth factors in the blood plasma, but takes place as a result of their release from the cells. Donated blood, irradiated with UV light of the samemore » wavelength and within the same dose range as are used under clinical conditions (up to 1200 J/m/sup 2/), possesses growth-stimulating properties.« less

Protective effect of gelatin and gelatin hydrolysate from salmon skin on UV irradiation-induced photoaging of mice skin

NASA Astrophysics Data System (ADS)

Chen, Tiejun; Hou, Hu; Lu, Jiaohan; Zhang, Kai; Li, Bafang

2016-08-01

The objective of this study was to investigate the effect of gelatin (SG) isolated from salmon skin and its hydrolysate (SGH) on photoaging skin, and the mechanism responsible for anti-photoaging. The average molecular weights of SG and SGH were 65 kDa and 873 Da, respectively. The amino acid compositions of SG and SGH were similar. Both of them were abundant in hydrophobic amino acids. Twenty-five peptides were identified from SGH. SG and SGH could improve UV irradiation-induced pathological changes of macroscopical tissue texture and skin morphology. Hydroxyproline content is an indicator of matrix collagen content, SG and SGH could inhibit the decrease of hydroxyproline content in photoaging skin in a dose dependent manner. In addition, SG and SGH could alleviate UV irradiation-induced oxidative damages to skin by increasing the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), increasing the content of glutathione (GSH) and decreasing the content of malonaldehyde (MDA). Moreover, SG and SGH could enhance immune regulation system by increasing the thymus index. Thus, the anti-photoaging mechanisms of SG and SGH were by inhibiting the depletion of antioxidant defense components, involving in the synthesis of collagen and enhancing the function of immune system. Besides, SGH showed a better result in protecting skin from photoaging than SG.

UVB radiation and its role in the treatment of postmenopausal women with osteoporosis

NASA Astrophysics Data System (ADS)

Falkenbach, A.; Sedlmeyer, Annette; Unkelbach, Uwe

In humans, the serum concentration of parathyroid hormone (PTH) is higher in winter than in summer. The increase of PTH can be suppressed by oral vitamin D supplements, which is considered beneficial to those with osteoporosis. The present study investigates whether this effect can also be achieved by serial ultraviolet (UV) irradiation of the skin. In total, 34 women suffering from postmenopausal osteoporosis were included in the open trial. In late winter, 20 patients were irradiated with a spectrum containing UVB, eight times over a period of 4 weeks. The serum concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2D], PTH, osteocalcin, alkaline phosphatase (AP), calcium and phosphorus were measured before the first, and 2 days after the last, dose of radiation. The data were compared to the controls (n=14, no UV exposure), who were evaluated once at the start of the study and then again 4 weeks later. After UV irradiation the level of 25(OH)D was increased, whilst that of PTH remained unchanged. The serum level of osteocalcin decreased in the control group, but did not change in the group of women who had been exposed to UV radiation. The present study of osteoporotic women does not confirm previous findings in studies of healthy volunteers i.e. that PTH can be suppressed by exposure to UVB radiation in winter. Further studies are required to specify whether there are subgroups of osteoporotic people who may benefit from exposure to UVB radiation during winter.

Absolute spectral response measurements of different photodiodes useful for applications in the UV spectral region

NASA Astrophysics Data System (ADS)

Pelizzo, Maria G.; Ceccherini, Paolo; Garoli, Denis; Masut, Pietro; Nicolosi, Piergiorgio

2004-09-01

Long UV radiation exposure can result in damages of biological tissues, as burns, skin aging, erythema and even melanoma cancer. In the past years an increase of melanoma cancer has been observed and associated to the atmospheric ozone deployment. Attendance of sun tanning unit centers has become a huge social phenomena, and the maximum UV radiation dose that a human being can receive is regulated by law. On the other side, UV radiation is largely used for therapeutic and germicidal purposes. In all these areas, spectroradiometer and radiomenter are needed for monitoring UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm) irradiance. We have selected some commercial photodiodes which can be used as solid state detectors in these instruments. We have characterized them by measuring their absolute spectral response in the 200 - 400 nm spectral range.

New bactericidal UV light sources: excilamps

NASA Astrophysics Data System (ADS)

Sosnin, Edward A.; Lavrent'eva, Larisa V.; Erofeev, Mikhail V.; Masterova, Yana V.; Kuznetzova, Eugenia N.; Tarasenko, Victor F.

2004-05-01

A reliable bactericidal effect on Escherichia coli cells irradiation by excilamps has been established. Both on primary and secondary irradiation there exists the reciprocally proportional dependence between irradiation doze (or exposure time) and survived cells number. The microorganisms survived after primary irradiation are shown to have not changed sensitivity to excilamps irradiation. The best results have been obtained during XeBr-excilamp irradiation. Owing to their technical parameters, the excilamps are promising systems for UV-sterilization. Comparison of capacitive discharge excilamp characteristics with other conventional UV light sources in presented. A comparative study on UV doze effect of a barrier discharge KrCl-excilamp (λ = 222 nm) on Staphylococcus aureus and Escherichia coli inactivation was carried out. KrCl-excilamp emission power is 65 W, and emitting area is 0.1 m2. It has been demonstrated that Staphylococcus aureus cell sensitivity to UV radiation at this wavelength is higher than that of Escherichia coli.

Effect of gamma irradiation on the structural, mechanical and optical properties of polytetrafluoroethylene sheet

NASA Astrophysics Data System (ADS)

Mohammadian-Kohol, M.; Asgari, M.; Shakur, H. R.

2018-04-01

In this study, the effects of gamma radiation on the chemical structure, mechanical and optical properties of polytetrafluoroethylene (PTFE) sheet were investigated with various doses up to 12 kGy. The chemical changes in the structure were studied by FTIR spectroscopy. Also, effects of radiation on the different mechanical parameters such as Young's modulus, toughness, strain, and stress were studied at the maximum tolerable force and the fracture points. Furthermore, changing the various optical parameters such as absorption coefficient, Urbach energy, optical band gaps, refractive index, optical dispersion parameters and plasma resonance frequency were studied by UV-visible spectroscopy. Formation of a band at 1594 cm-1, which was belonged to double carbon bonds, indicated that chain-scission was occurred at 12 kGy gamma irradiation dose. As well, the mechanical results showed an increase in the elastic behavior of PTFE sheets and a decrease in the plastic behavior of it with absorbed dose increasing. Moreover, the results showed that gamma irradiation can effectively change the various optical properties of PTFE sheets due to different phenomena such as degradation of the main chains, occurring chain-scission, formation of free radicals and cross-linking in the polymer structure.

An LED-based UV-B irradiation system for tiny organisms: System description and demonstration experiment to determine the hatchability of eggs from four Tetranychus spider mite species from Okinawa.

PubMed

Suzuki, Takeshi; Yoshioka, Yoshio; Tsarsitalidou, Olga; Ntalia, Vivi; Ohno, Suguru; Ohyama, Katsumi; Kitashima, Yasuki; Gotoh, Tetsuo; Takeda, Makio; Koveos, Dimitris S

2014-03-01

We developed a computer-based system for controlling the photoperiod and irradiance of UV-B and white light from a 5×5 light-emitting diode (LED) matrix (100×100mm). In this system, the LED matrix was installed in each of four irradiation boxes and controlled by pulse-width modulators so that each box can independently emit UV-B and white light at irradiances of up to 1.5 and 4.0Wm(-2), respectively, or a combination of both light types. We used this system to examine the hatchabilities of the eggs of four Tetranychus spider mite species (T. urticae, T. kanzawai, T. piercei and T. okinawanus) collected from Okinawa Island under UV-B irradiation alone or simultaneous irradiation with white light for 12hd(-1) at 25°C. Although no eggs of any species hatched under the UV-B irradiation, even when the irradiance was as low as 0.02Wm(-2), the hatchabilities increased to >90% under simultaneous irradiation with 4.0Wm(-2) white light. At 0.06Wm(-2) UV-B, T. okinawanus eggs hatched (15% hatchability) under simultaneous irradiation with white light, whereas other species showed hatchabilities <1%. These results suggest that photolyases activated by white light may reduce UV-B-induced DNA damage in spider mite eggs and that the greater UV-B tolerance of T. okinawanus may explain its dominance on plants in seashore environments, which have a higher risk of exposure to reflected UV-B even on the undersurface of leaves. Our system will be useful for further examination of photophysiological responses of tiny organisms because of its ability to precisely control radiation conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis and characterization of zinc chloride containing poly(acrylic acid) hydrogel by gamma irradiation

NASA Astrophysics Data System (ADS)

Park, Jong-Seok; Kuang, Jia; Gwon, Hui-Jeong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Seob Khil, Myung; Nho, Young-Chang

2013-07-01

In this study, the characterization of zinc chloride incorporated into a poly(acrylic acid) (PAAc) hydrogel prepared by gamma-ray irradiation was investigated. Zinc chloride powder with different concentrations was dissolved in the PAAc solution, and it was crosslinked with gamma-ray irradiation. The effects of various parameters such as zinc ion concentration and irradiation doses on characteristics of the hydrogel formed were investigated in detail for obtaining an antibacterial wound dressing. In addition, the gel content, pH-sensitive (pH 4 or 7) swelling ratio, and UV-vis absorption spectra of the zinc particles in the hydrogels were characterized. Moreover, antibacterial properties of these new materials against Staphylococcus aureus and Escherichia coli strains were observed on solid growth media. The antibacterial tests indicated that the zinc chloride containing PAAc hydrogels have good antibacterial activity.

Photostability of 6-MAM and morphine exposed to controlled UV irradiation in water and methanol solution: HRMS for the characterization of transformation products and comparison with the dry state.

PubMed

Miolo, Giorgia; Tucci, Marianna; Mazzoli, Alessandra; Ferrara, Santo Davide; Favretto, Donata

2016-07-15

The UVA and UVB light-induced behaviour of 6-monoacetylmorphine (6-MAM) and morphine, the main metabolites of heroin, was studied in methanol, aqueous solution and in the dry state. UVA and UVB irradiations were performed for different times (radiant energies of 20-300J/cm(2)). UV spectra of irradiated samples were compared with samples kept in the dark. To estimate the extent of photolysis, positive ion electrospray ionization experiments were performed on the irradiated samples by LC-HRMS. Tentative identification of photoproducts was performed on the basis of their elemental formula as calculated by HRMS results. Morphine and 6-MAM demonstrated to be quite stable under UVA light but very sensitive to UVB irradiation. In methanol solutions they undergo a similar pattern, both reaching 90% photodegradation after 100J/cm(2) of UVB, with a slightly faster kinetic for morphine at lower doses. In water, the yields of photodegradation are nearly one third lower than in methanol. In the solid state, the yield of photodegradation is lower than in solution. The structures of some UVB-induced degradation products are proposed. Photoaddition of the solvent and photooxidation seem the main pathways of phototransformation of these molecules. Moreover, both compounds revealed to generate singlet oxygen under UVB exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultraviolet B eye irradiation aggravates atopic dermatitis via adrenocorticotropic hormone and NLRP3 inflammasome in NC/Nga mice.

PubMed

Hiramoto, Keiichi; Yamate, Yurika; Yokoyama, Satoshi

2018-05-01

Ultraviolet (UV) B irradiation has been shown to improve atopic dermatitis (AD). However, the relationship between UVB eye irradiation and AD is not known. This issue was addressed using a mouse model of AD. The eyes of NC/Nga mice were irradiated with UVB at a dose of 1.0 kJ/m 2 using a 20SE sunlamp for the duration of the experimental period. AD symptoms deteriorated upon UVB eye irradiation. The levels of adrenocorticotropic hormone (ACTH) in the plasma and nucleotide-binding domain and leucine-rich-containing family, pyrin domain-containing (NLRP)3 and neutrophil markers in the skin were increased in UVB-irradiated mice. Treatment with inhibitors of ACTH, caspase-1, interleukin-18, and thymic stromal lymphopoietin (TSLP) partly reversed the effects of irradiation, with the greatest improvement observed upon ACTH inhibition. The NLRP3 inflammasome was implicated in the effects of UVB irradiation. UVB eye irradiation causes AD symptom deterioration, which is likely mediated by ACTH and the activity of the inflammasome. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

UV decreases the synthesis of free fatty acids and triglycerides in the epidermis of human skin in vivo, contributing to development of skin photoaging.

PubMed

Kim, Eun Ju; Jin, Xing-Ji; Kim, Yeon Kyung; Oh, In Kyung; Kim, Ji Eun; Park, Chi-Hyun; Chung, Jin Ho

2010-01-01

Although fatty acids are known to be important in various skin functions, their roles on photoaging in human skin are poorly understood. We investigated the alteration of lipid metabolism in the epidermis by photoaging and acute UV irradiation in human skin. UV irradiated young volunteers (21-33 years, n=6) and elderly volunteers (70-75 years, n=7) skin samples were obtained by punch biopsy. Then the epidermis was separated from dermis and lipid metabolism was investigated. We observed that the amounts of free fatty acids (FFA) and triglycerides (TG) in the epidermis of photoaged or acutely UV irradiated human skin were significantly decreased. The expressions of genes related to lipid synthesis, including acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase (SCD), sterol regulatory element binding proteins (SREBPs), and peroxisome proliferator-activated receptors (PPARgamma) were also markedly decreased. To elucidate the significance of these changes of epidermal lipids in human skin, we investigated the effects of TG or various inhibitors for the enzymes involved in TG synthesis on the expression of matrix metalloproteinase-1 (MMP-1) in cultured human epidermal keratinocytes. We demonstrated that triolein (TG) reduced basal and UV-induced MMP-1 mRNA expression. In addition, each inhibitor for various lipid synthesis enzymes, such as TOFA (ACC inhibitor), cerulenin (FAS inhibitor) and trans-10, cis-12-CLA (SCD inhibitor), increased the MMP-1 expression significantly in a dose-dependent manner. We also demonstrated that triolein could inhibit cerulenin-induced MMP-1 expression. Furthermore, topical application of triolein (10%) significantly prevented UV-induced MMP-13, COX-2, and IL-1beta expression in hairless mice. Our results suggest that TG and FFA may play important roles in photoaging of human skin. Copyright 2009 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

CAPTURE OF MERCURY IN COMBUSTION SYSTEMS BY IN SITU-GENERATED TITANIA PARTICLES WITH UV IRRADIATION

EPA Science Inventory

In-situ-generated sorbent titania particles with ultraviolet (UV) irradiation have been shown to be effective in capture of mercury in combustor exhausts. Results of experiments conducted with the (1) sorbent precursor only, (2) mercury only, (3) mercury and UV irradiation, and (...

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

NASA Astrophysics Data System (ADS)

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

2009-02-01

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

Empirical evaluation of global vitamin D effective ultraviolet irradiances under cloudy conditions for a subtropical southern hemisphere site.

PubMed

Turnbull, David J; Parisi, Alfio V; Schouten, Peter W

2010-05-01

This paper evaluates the global vitamin D effective UV (UV(vitd)) irradiances under cloudy conditions at a subtropical, southern hemisphere site. The UV(vitd) irradiances were analyzed on a horizontal plane and sampled at 5-min intervals over 18 months so that a wide range of parameters including cloud conditions, solar zenith angles (SZA) and ozone levels were taken into account. Cloud modification factors were determined from the influence of clouds on the global broadband solar radiation, and these were applied to the cloud-free vitamin D effective UV irradiance to evaluate the UV(vitd) irradiances on a horizontal plane for cloudy conditions. For vitamin D effective UV irradiance, cloud modification factors were found to range from 0.9 to 1.0 for no cloud and 0.4 to 0.5 for 8 octa of cloud cover. SZA played a minimal role in this variation. A comparison of the measured and calculated UV(vitd) irradiances for the 2004 data set in the range of SZA of 70 degrees or less provided an R(2) value of 0.90. The output of the model was compared to data measured during the first 6 months of 2005 for an SZA of 70 degrees or less and provided an R(2) value of approximately 0.82.

Insights into the mechanism of X-ray-induced disulfide-bond cleavage in lysozyme crystals based on EPR, optical absorption and X-ray diffraction studies.

PubMed

Sutton, Kristin A; Black, Paul J; Mercer, Kermit R; Garman, Elspeth F; Owen, Robin L; Snell, Edward H; Bernhard, William A

2013-12-01

Electron paramagnetic resonance (EPR) and online UV-visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage. Online UV-visible spectroscopy showed that upon X-irradiation, disulfide radicalization appeared to saturate at an absorbed dose of approximately 0.5-0.8 MGy, in contrast to the saturating dose of ∼0.2 MGy observed using EPR at much lower dose rates. The observations suggest that a multi-track model involving product formation owing to the interaction of two separate tracks is a valid model for radiation damage in protein crystals. The saturation levels are remarkably consistent given the widely different experimental parameters and the range of total absorbed doses studied. The results indicate that even at the lowest doses used for structural investigations disulfide bonds are already radicalized. Multi-track considerations offer the first step in a comprehensive model of radiation damage that could potentially lead to a combined computational and experimental approach to identifying when damage is likely to be present, to quantitate it and to provide the ability to recover the native unperturbed structure.

An Estimate of Changes in the Sun's Total Irradiance Caused by UV Irradiance Variations from 1874 to 1988

NASA Technical Reports Server (NTRS)

Lean, J.

1990-01-01

Enhanced emission from bright solar faculae is a source of significant variation in the sun's total irradiance. Relative to the emission from the quiet sun, facular emission is known to be considerably greater at UV wavelengths than at visible wavelengths. Determining the spectral dependence of facular emission is of interest for the physical insight this may provide to the origin of the sun's irradiance variations. It is also of interest because solar radiation at lambda less than 300 nm is almost totally absorbed in the Earth's atmosphere. Depending on the magnitude of the UV irradiance variations, changes in the sun's irradiance that penetrates to the Earth's surface may not be equivalent to total irradiance variations measured above the Earth's atmosphere. Using an empirical model of total irradiance variations which accounts separately for changes caused by bright faculae from those associated with dark sunspots, the contribution of UV irradiance variations to changes in the sun's total irradiance is estimated during solar cycles 12 to 21.

Synthesis of CdS nanorods in soft template under gamma-irradiation.

PubMed

Zhao, Bing; Wang, Yanli; Zhang, Haijiao; Jiao, Zheng; Wang, Haobo; Ding, Guoji; Wu, Minghong

2009-02-01

CdS nano material which has a band gap of 2.42 eV at room temperature is a typical II-VII semiconductor having many commercial or potential applications, e.g., light-emitting diodes, solar cell and optoelectronic devices. In this paper, we use a new strategy to synthesize CdS nanorods. CdS nanorods were prepared in soft template under gamma-irradiation though the reaction of cadmium sulphide and thiacetamide (TAA). The formation process and characters of CdS nanorods was investigated in detail by transmission electron microscopy (TEM), electron diffraction (ED) pattern, X-ray powder diffraction (XRD), ultraviolet spectrophotometer (UV) and photoluminescence spectrophotometer (PL). In the experiment we proposed that the irradiation of gamma-ray accelerated the formation of S(2-) under acidic condition (pH = 3) and vinyl acetate (VAc) monomer formed pre-organized nano polymer tubules which were used as both templates and nanoreacters for the growth of CdS nanorods. In this process, we have obtained the CdS polycrystal nanorods with PVAc nano tubules and CdS single-crystal nanorods. The result of X-ray powder diffraction confirms that the crystal type of CdS nanorods is cubic F-43 m (216). The results from transmission electron microscopy and electron diffraction show that the concentrations of reactants and the dose rate of gamma-ray are key to produce appropriate CdS nanorods. Relatively low concentrations (Cd2+: 0.008-0.02 mol/L, Cd2+ : S(2-) = 1 : 2) of reactants and long time (1-2 d) of irradiation in low dose rate (6-14 Gy/min) are propitious to form CdS single-crystal nanorods with small diameter (less than 100 nm) and well length (2-5 microm). UV and PL characterizations show the sample have well optical properties.

Calculating Solar Ultraviolet Irradiation Of The Human Cornea And Corresponding Required Sunglass Lens Transmittances

NASA Astrophysics Data System (ADS)

Hoover, Herbert L.; Marsaud, Serge G.

1986-05-01

Tinted ophthalmic lenses are used primarily for eye comfort in a brightly lit environment. An ancillary benefit is the attenuation of ultraviolet radiation. Some national product standards specify quantitative limits for ultraviolet transmittances. Such limits ought to be founded on quantitative estimates of solar irradiances of ocular tissues, with actinic effectiveness taken into account. We use the equations of Green and coworkers for direct and diffuse solar irradiance at the earth's surface to calculate average sky and ground spectral radiances. We use the geometric factors derived by us for the coupling of radiation from these sources to the human cornea. Actinically weighted corneal spectral irradiances integrated over wavelength and time yield peak irradiances and accumulated exposure doses that are compared with recommended exposure limits. This provides the maximal effective ultraviolet transmittances of tinted ophthalmic lenses such that these exposure limits will not be exceeded in the selected exposure environment. The influences on corneal irradiation of such exposure parameters as solar zenith angle, altitude of the exposure site, characteristics of atmospheric aerosols, and ground reflectances are illustrated. The relationships between the effective transmittance (which is a function of the environmental radiation and any actinicweighting function) and readily determined characteristics of the lens itself, viz., its mean transmittance, and a selected spectral transmittance, are derived for three lens transmittance curves. Limits of lens transmittance for the UV-B and UV-A wavelength regions are presented for several representative exposure sites in Europe and the U.S.A.

Zinc finger protein 598 inhibits cell survival by promoting UV-induced apoptosis.

PubMed

Yang, Qiaohong; Gupta, Romi

2018-01-19

UV is one of the major causes of DNA damage induced apoptosis. However, cancer cells adopt alternative mechanisms to evade UV-induced apoptosis. To identify factors that protect cancer cells from UV-induced apoptosis, we performed a genome wide short-hairpin RNA (shRNA) screen, which identified Zinc finger protein 598 (ZNF598) as a key regulator of UV-induced apoptosis. Here, we show that UV irradiation transcriptionally upregulates ZNF598 expression. Additionally, ZNF598 knockdown in cancer cells inhibited UV-induced apoptosis. In our study, we observe that ELK1 mRNA level as well as phosphorylated ELK1 levels was up regulated upon UV irradiation, which was necessary for UV irradiation induced upregulation of ZNF598. Cells expressing ELK1 shRNA were also resistant to UV-induced apoptosis, and phenocopy ZNF598 knockdown. Upon further investigation, we found that ZNF598 knockdown inhibits UV-induced apoptotic gene expression, which matches with decrease in percentage of annexin V positive cell. Similarly, ectopic expression of ZNF598 promoted apoptotic gene expression and also increased annexin V positive cells. Collectively, these results demonstrate that ZNF598 is a UV irradiation regulated gene and its loss results in resistance to UV-induced apoptosis.

[Efficiency of photodecomposition of trace NDMA in water by UV irradiation].

PubMed

Xu, Bing-Bing; Chen, Zhong-Lin; Qi, Fei; Ma, Jun

2008-07-01

Efficiency of photodecomposition of trace NDMA by UV irradiation was investigated with analyzing the initial concentration of NDMA, solution pH, irradiation area, irradiation intensity and water quality effect on NDMA photolysis. NDMA could be effectively photodegraded by UV irradiation. The removal efficiency of NDMA was 97.5% after 5 min of UV irradiation. Effect of initial NDMA concentration on photodecomposition of NDMA was not remarkable. With pH value ascending, the removal rate of NDMA photodecomposition decreased. The yields of photoquantum were more under lower solution pH than that under higher pH. NDMA had fastest reaction rate at solution pH = 2.2. Removal efficiency of NDMA increased with the available irradiation area ascending. Increscent ultraviolet irradiation intensity was good for NDMA degradation. Water quality affected the removal of NDMA slightly. The removal efficiency of NDMA in tap water and Songhua River raw water were 96.7% and 94.8%, respectively.

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

NASA Astrophysics Data System (ADS)

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

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

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

Sanchez-Mejorada, G.; Frias, D.

A theoretical model is presented for the evaluation of the energy transferred during the interaction of high energy radiation with icy bodies. Numerical simulations of the chemical reaction system reproduce the behavior of the icy systems (frozen solution of iron salts) after its interaction with the gamma radiation. Simulation experiments of extraterrestrial bodies are useful for space research, where low temperature dosimetry is necessary, especially in trips with humans or in the International Space Station (ISS) where humans are exposed to high radiation doses. The results showed that theoretical model applied for the irradiated system for different doses (from 10more » to 2500Gy) and at different temperature (from 77 to 298 deg. K). The system under study was frozen solutions of iron salts and were analyzed (after Melting) by UV-spectroscopy. The systems were irradiates with gamma radiation. It is also shown that the response of the system is a function of the temperature and it was linear with as a function of dose.« less

Effect of uv light on formation and synthetic capacity of DNA-membrane complexes from T7-infected cells of E. coli

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

Wintermantel, G.

1974-02-01

The action of uv light on the attachment of T7-DNA to the bacterial cell membrane, and the RNA- and DNA-synthesizing activity of the DNA-membrane complex, were investigated. In E. coli H560 cells infected by uv-irradiated T7 phages, the amount of membrane-associated parental /sup 32/P-labeled T7-DNA was determined. To measure the RNA- and DNA-synthesizing activity, the isolated DNA- membrane complexes were incubated with an equimolar mixture of the corresponding four nucleoside triphosphates. The uv-sensitivities of the functions tested were calculated from the slopes of the dose-effect curves. In relation to the uv- sensitivity for plaque-forming ability of the T7bacteriophages they amountmore » to 0.07 ( plus or minus 0.01); 0.15 ( plus or minus 0.01); and 0.56 ( plus or minus 0.04), respectively. (auth)« less

Increased affinity of endothelial cells to NiTi using ultraviolet irradiation: An in vitro study.

PubMed

Tateshima, Satoshi; Kaneko, Naoki; Yamada, Masahiro; Duckwiler, Gary; Vinuela, Fernando; Ogawa, Takahiro

2018-04-01

Nickel-titanium alloy (NiTi) is one of the most popular materials used endovascularly because of its shape memory and superelasticity. The NiTi device needs to be covered by endothelial cells after being placed in the blood vessel to reduce ischemic complications. The objective of this study was to examine the impact of ultraviolet (UV) irradiation on the biocompatibility of NiTi surfaces with endothelial cells. NiTi sheets were treated with UV irradiation for 48 h and human aorta derived endothelial cells were used in this study. UV irradiation converted the NiTi surface to hydrophilic state and increased albumin adsorption. The number of endothelial cell migration, attachment, proliferation as well as their metabolic activity were significantly increased on UV treated NiTi. This study provides the first evidence of the photoactivation of NiTi surfaces by UV irradiation and demonstrates improved biocompatibility of UV-treated NiTi surfaces with vascular endothelial cells. These results suggest that UV irradiation may promote endothelialization of NiTi devices in blood vessels. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1034-1038, 2018. © 2017 Wiley Periodicals, Inc.

Institutional Tuberculosis Transmission. Controlled Trial of Upper Room Ultraviolet Air Disinfection: A Basis for New Dosing Guidelines.

PubMed

Mphaphlele, Matsie; Dharmadhikari, Ashwin S; Jensen, Paul A; Rudnick, Stephen N; van Reenen, Tobias H; Pagano, Marcello A; Leuschner, Wilhelm; Sears, Tim A; Milonova, Sonya P; van der Walt, Martie; Stoltz, Anton C; Weyer, Karin; Nardell, Edward A

2015-08-15

Transmission is driving the global tuberculosis epidemic, especially in congregate settings. Worldwide, natural ventilation is the most common means of air disinfection, but it is inherently unreliable and of limited use in cold climates. Upper room germicidal ultraviolet (UV) air disinfection with air mixing has been shown to be highly effective, but improved evidence-based dosing guidelines are needed. To test the efficacy of upper room germicidal air disinfection with air mixing to reduce tuberculosis transmission under real hospital conditions, and to define the application parameters responsible as a basis for proposed new dosing guidelines. Over an exposure period of 7 months, 90 guinea pigs breathed only untreated exhaust ward air, and another 90 guinea pigs breathed only air from the same six-bed tuberculosis ward on alternate days when upper room germicidal air disinfection was turned on throughout the ward. The tuberculin skin test conversion rates (>6 mm) of the two chambers were compared. The hazard ratio for guinea pigs in the control chamber converting their skin test to positive was 4.9 (95% confidence interval, 2.8-8.6), with an efficacy of approximately 80%. Upper room germicidal UV air disinfection with air mixing was highly effective in reducing tuberculosis transmission under hospital conditions. These data support using either a total fixture output (rather than electrical or UV lamp wattage) of 15-20 mW/m(3) total room volume, or an average whole-room UV irradiance (fluence rate) of 5-7 μW/cm(2), calculated by a lighting computer-assisted design program modified for UV use.

Proteomic and Metabolomic Analyses of Leaf from Clematis terniflora DC. Exposed to High-Level Ultraviolet-B Irradiation with Dark Treatment.

PubMed

Yang, Bingxian; Wang, Xin; Gao, Cuixia; Chen, Meng; Guan, Qijie; Tian, Jingkui; Komatsu, Setsuko

2016-08-05

Clematis terniflora DC. has potential pharmaceutical value; on the contrary, high-level UV-B irradiation with dark treatment led to the accumulation of secondary metabolites. Metabolomic and proteomic analyses of leaf of C. terniflora were performed to investigate the systematic response mechanisms to high-level UV-B irradiation with dark treatment. Metabolites related to carbohydrates, fatty acids, and amino acids and/or proteins related to stress, cell wall, and amino acid metabolism were gradually increased in response to high-level UV-B irradiation with dark treatment. On the basis of cluster analysis and mapping of proteins related to amino acid metabolism, the abundances of S-adenosylmethionine synthetase and cysteine synthase as well as 1,1-diphenyl-2-picrylhydrazyl scavenging activity were gradually increased in response to high-level UV-B irradiation with dark treatment. Furthermore, the abundance of dihydrolipoyl dehydrogenase/glutamate dehydrogenase and the content of γ-aminobutyric acid were also increased following high-level UV-B irradiation with dark treatment. Taken together, these results suggest that high-level UV-B irradiation with dark treatment induces the activation of reactive oxygen species scavenging system and γ-aminobutyric acid shunt pathway in leaf of C. terniflora.

Bystander effects in unicellular organisms.

PubMed

DeVeaux, Linda C; Durtschi, Lynn S; Case, Jonathan G; Wells, Douglas P

2006-05-11

Radiation-induced bystander effects have been seen in mammalian cells from diverse origins. These effects can be transmitted through the medium to cells not present at the time of irradiation. We have developed an assay for detecting bystander effects in the unicellular eukaryote, the fission yeast Schizosaccharomyces pombe. This assay allows maximal exposure of unirradiated cells to cells that have received electron beam irradiation. S. pombe cells were irradiated with 16-18 MeV electrons from a pulsed electron LINAC. When survival of the irradiated cells decreased to approximately 50%, forward-mutation to 2-deoxy-d-glucose resistance increased in the unirradiated bystander cells. Further increase in dose had no additional effect on this increase. In order to detect this response, it was necessary for the irradiated cell/unirradiated cell ratio to be high. Other cellular stresses, such as heat treatment, UV irradiation, and bleomycin exposure, also caused a detectable response in untreated cells grown with the treated cells. We discuss evolutionary implications of these results.

Effects of γ-ray irradiation on optical absorption and laser damage performance of KDP crystals containing arsenic impurities.

PubMed

Guo, D C; Jiang, X D; Huang, J; Wang, F R; Liu, H J; Xiang, X; Yang, G X; Zheng, W G; Zu, X T

2014-11-17

The effects of γ-irradiation on potassium dihydrogen phosphate crystals containing arsenic impurities are investigated with different optical diagnostics, including UV-VIS absorption spectroscopy, photo-thermal common-path interferometer and photoluminescence spectroscopy. The optical absorption spectra indicate that a new broad absorption band near 260 nm appears after γ-irradiation. It is found that the intensity of absorption band increases with the increasing irradiation dose and arsenic impurity concentration. The simulation of radiation defects show that this absorption is assigned to the formation of AsO₄⁴⁻ centers due to arsenic ions substituting for phosphorus ions. Laser-induced damage threshold test is conducted by using 355 nm nanosecond laser pulses. The correlations between arsenic impurity concentration and laser induced damage threshold are presented. The results indicate that the damage performance of the material decreases with the increasing arsenic impurity concentration. Possible mechanisms of the irradiation-induced defects formation under γ-irradiation of KDP crystals are discussed.

The phototoxic and photoallergy potential of clindamycin phosphate 1.2%/ tretinoin 0.025% gel for facial acne: results of two single-center, evaluator-blinded, randomized, vehicle-controlled phase 1 studies in healthy volunteers.

PubMed

Murray, John; Potts, Aaron

2014-01-01

A fixed-dose combination of clindamycin phosphate 1.2% and tretinoin 0.025% gel (VELTIN® (clindamycin phosphate and tretinoin) 1.2%/0.025% Gel [VELTIN]) (clindamycin/tretinoin gel) is currently available for the once-daily topical treatment of acne. Two-phase I studies were conducted to evaluate the phototoxic and photoallergic potential of clindamycin/tretinoin gel. Study 1 (phototoxic) (n=37) and Study 2 (photoallergic) (n=58) were single-center, evaluator-blinded, randomized, vehicle-controlled, phase 1 studies conducted in healthy volunteers. In Study 1, clindamycin/tretinoin gel patches, vehicle gel patches and blank patches (no gel) were applied concurrently for 24 hours to naïve sites. After patch removal, sites were irradiated with 16 joules/cm2 of ultraviolet A light (UVA) then 0.75 minimal erythema dose (MED) of UVA/ultraviolet B light (UVB), the same irradiation protocol followed by 15 joules/cm2 of visible light (VIS), or served as non-irradiated controls. Study 2 examined the effect of repeated drug exposure and involved an induction period (6 repeat phases at the same body sites during which clindamycin/tretinoin gel and vehicle gel patches were applied for 24 hours, removed and sites irradiated with UVB +/- VIS), followed by a rest period (10 to 17 days), then a challenge period that used the protocol described for Study 1. In both studies, inflammatory responses and other cutaneous effects were evaluated at 1, 24, 48, and 72 hours after patch removal. No subject experienced any adverse events in Study 1 (phototoxic). One subject in Study 2 (photoallergic) experienced AEs (diffuse erythema; mild application site irritation at one each of UV/VIS-irradiated clindamycin/tretinoin gel and vehicle gel patch sites) considered definitely related to study product that resulted in discontinuation from the study. Data from Study 1 and the challenge phase from Study 2 showed most subjects had no visible inflammatory reaction to clindamycin/tretinoin gel after irradiation. Clindamycin/tretinoin gel has a favorable safety profile following UV/visible irradiation and a low potential for phototoxicity and photoallergenicity.

EFFECT OF UV IRRADIATION ON ORGANIC MATTER EXTRACTED FROM TREATED OHIO RIVER WATER STUDIED THROUGH THE USE OF ELECTROSPRAY MASS SPECTROMETRY

EPA Science Inventory

Ohio River water was treated by settling, sand filtration, and granular activated carbon filtration. It was then irradiated by low pressure (monochromatic) and medium pressure (polychromatic) UV lamps to investigate the effects of UV irradiation of natural organic matter (NOM). ...

UV hazard on Italian Apennines under different shading and ground cover conditions during peak tourist seasons of the year.

PubMed

Grifoni, Daniele; Carreras, Giulia; Sabatini, Francesco; Zipoli, Gaetano

2006-12-01

In solar UV irradiance monitoring and forecasting services UV information is generally expressed in terms of its effect on erythema and referred to horizontal surface. In this work we define the UV radiative regime, in terms of biologically effective UV irradiance (UVBE) for skin and eye, under full sun and shaded conditions, over a mountainous tourist area of central Italy by means of two all-day measurements (summer and early spring) with different ground albedo (grass and snow cover respectively). UV irradiance was monitored on tilted surfaces (the most frequent for people standing and walking). Results show the significant contribution of ground albedo and sun position in determining the incident UVBE irradiance. On early spring days the UVBE irradiance measured on horizontal surface was much lower than on tilted ones; the opposite condition was observed in summer. The highest UVBE irradiance values, in particular conditions of sun elevation and ground cover, were reached in periods different from the summer both in full sun and shaded condition.

Kinetics of patulin degradation in model solution, apple cider and apple juice by ultraviolet radiation.

PubMed

Zhu, Yan; Koutchma, Tatiana; Warriner, Keith; Shao, Suqin; Zhou, Ting

2013-08-01

Patulin is a mycotoxin produced by a wide range of molds involved in fruit spoilage, most commonly by Penicillium expansum and is a health concern for both consumers and manufacturers. The current study evaluated feasibility of monochromatic ultraviolet (UV) radiation at 253.7 nm as a possible commercial application for the reduction of patulin in fresh apple cider and juice. The R-52G MINERALIGHT® UV bench top lamp was used for patulin destruction. It was shown that 56.5%, 87.5%, 94.8% and 98.6% reduction of patulin can be achieved, respectively, in the model solution, apple cider, apple juice without ascorbic acid addition and apple juice with ascorbic acid addition in 2-mm thickness sample initially spiked by 1 mg·L(-1) of patulin after UV exposure for 40 min at UV irradiance of 3.00 mW·cm(-2). A mathematic model to compare the degradation rate and effective UV dose was developed. The effective UV doses that were directly absorbed by patulin for photochemical reaction were 430, 674, 724 and 763 mJ·cm(-3), respectively. The fluence-based decimal reduction time was estimated to 309.3, 31.3, 28.9 and 5.1 mW·cm(-2)·min, respectively, in four media mentioned above. The degradation of patulin followed the first-order reaction model. The time-based and fluence-based reaction rate constants were determined to predict patulin degradation. The time-based reaction rate constant of samples treated in dynamic regime with constant stirring (model solution: 2.95E-4 s(-1), juice: 4.31E-4 s(-1)) were significantly higher than samples treated in static regime (model solution: 2.79E-4 s(-1), juice: 3.49E-4 s(-1), p < 0.05) when applied UV irradiance and sample thickness were consistent. The reaction rate constant of patulin degradation in apple juice was significantly higher than model solution (p < 0.05). Although further investigations are still needed, the results of this study demonstrated that UV radiation may be an effective method for treating patulin-containing apple cider and juice.

Proxy-based reconstruction of erythemal UV doses over Estonia for 1955 2004

NASA Astrophysics Data System (ADS)

Eerme, K.; Veismann, U.; Lätt, S.

2006-08-01

A proxy-based reconstruction of the erythemally-weighted UV doses for 1955-2004 has been performed for the Tartu-Tõravere Meteorological Station (58°16' N, 26°28' E, 70 m a.s.l.) site. The pyrheliometer-measured daily sum of direct irradiance on partly cloudy and clear days, and the pyranometer-measured daily sum of global irradiance on overcast days were used as the cloudiness influence related proxies. The TOMS ozone data have been used for detecting the daily deviations from the climatic value (averaged annual cycle). In 1998-2004, the biases between the measured and reconstructed daily doses in 55.5% of the cases were within ±10% and in 83.5% of the cases within ±20%, on average. In the summer half-year these amounts were 62% and 88%, respectively. In most years the results for longer intervals did not differ significantly, if no correction was made for the daily deviations of total ozone from its climatic value. The annual and summer half-yearly erythemal doses (contributing, on average, 89% of the annual value) agreed within ±2%, except for the years after major volcanic eruptions and one extremely fine weather year (2002). Using the daily relative sunshine duration as a proxy without detailed correction for atmospheric turbidity results in biases of 2-4% in the summer half-yearly dose in the years after major volcanic eruptions and a few other years of high atmospheric turbidity. The year-to-year variations of the summer half-yearly erythemal dose in 1955-2004 were found to be within 92-111% relative to their average value. Exclusion of eight extreme years reduces this range for the remaining to 95-105.5%. Due to the quasi-periodic alternation of wet and dry periods, the interval of cloudy summers 1976-1993 regularly manifests summer half-yearly erythemal dose values lower than the 1955-2004 average. Since 1996/1997 midwinters have been darker than on average.

Temperature Effects of Ultraviolet Irradiation on Material Degradation

NASA Astrophysics Data System (ADS)

Mori, Kazuyuki; Ishizawa, Junichiro

Ultraviolet rays (UV) cause organic materials to deteriorate. UV irradiation ground testing is therefore important to understand the “adequate lifetime assessment” and the “end-of-life (EOL) characteristic” of materials used in space. In previous experiments, high temperatures were found to accelerate the UV degradation of cross-linked ethylene tetrafluoroethylene (X-ETFE). This causes concern of potentially similar effects in other materials. In this study, we evaluated UV degradation at high temperatures and subsequently determined materials usable in space that had shown accelerated degradation due to UV irradiation at high temperatures.

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.

New down-converter for UV-stable perovskite solar cells: Phosphor-in-glass

NASA Astrophysics Data System (ADS)

Roh, Hee-Suk; Han, Gill Sang; Lee, Seongha; Kim, Sanghyun; Choi, Sungwoo; Yoon, Chulsoo; Lee, Jung-Kun

2018-06-01

Degradation of hybrid lead halide perovskite by UV light is a crucial issue that limits the commercialization of lead halide perovskite solar cells (PSCs). To address this problem, phosphor-in-glass (PiG) is used to convert UV to visible light. Down-conversion of UV light by PiG dramatically increases UV-stability of PSCs and enables PSCs to harvest UV light that is currently wasted. Performance of PSCs with PiG layer does not change significantly during 100 h-long UV-irradiation, while conventional PSCs degrade quickly by 1 h-long UV-irradiation. After 100 h long UV-irradiation, power conversion efficiency of PSCs with PiG is 440% larger than that of conventional PSCs. This result points a direction toward PSCs which are very stable and highly efficient under UV light.

Optimizing UV Index determination from broadband irradiances

NASA Astrophysics Data System (ADS)

Tereszchuk, Keith A.; Rochon, Yves J.; McLinden, Chris A.; Vaillancourt, Paul A.

2018-03-01

A study was undertaken to improve upon the prognosticative capability of Environment and Climate Change Canada's (ECCC) UV Index forecast model. An aspect of that work, and the topic of this communication, was to investigate the use of the four UV broadband surface irradiance fields generated by ECCC's Global Environmental Multiscale (GEM) numerical prediction model to determine the UV Index. The basis of the investigation involves the creation of a suite of routines which employ high-spectral-resolution radiative transfer code developed to calculate UV Index fields from GEM forecasts. These routines employ a modified version of the Cloud-J v7.4 radiative transfer model, which integrates GEM output to produce high-spectral-resolution surface irradiance fields. The output generated using the high-resolution radiative transfer code served to verify and calibrate GEM broadband surface irradiances under clear-sky conditions and their use in providing the UV Index. A subsequent comparison of irradiances and UV Index under cloudy conditions was also performed. Linear correlation agreement of surface irradiances from the two models for each of the two higher UV bands covering 310.70-330.0 and 330.03-400.00 nm is typically greater than 95 % for clear-sky conditions with associated root-mean-square relative errors of 6.4 and 4.0 %. However, underestimations of clear-sky GEM irradiances were found on the order of ˜ 30-50 % for the 294.12-310.70 nm band and by a factor of ˜ 30 for the 280.11-294.12 nm band. This underestimation can be significant for UV Index determination but would not impact weather forecasting. Corresponding empirical adjustments were applied to the broadband irradiances now giving a correlation coefficient of unity. From these, a least-squares fitting was derived for the calculation of the UV Index. The resultant differences in UV indices from the high-spectral-resolution irradiances and the resultant GEM broadband irradiances are typically within 0.2-0.3 with a root-mean-square relative error in the scatter of ˜ 6.6 % for clear-sky conditions. Similar results are reproduced under cloudy conditions with light to moderate clouds, with a relative error comparable to the clear-sky counterpart; under strong attenuation due to clouds, a substantial increase in the root-mean-square relative error of up to 35 % is observed due to differing cloud radiative transfer models.

Radiation enhanced reactivation of herpes simplex virus: effect of caffeine.

PubMed

Hellman, K B; Lytle, C D; Bockstahler, L E

1976-09-01

Ultaviolet enhanced (Weigle) reactivation of UV-irradiated herpes simplex virus in UV-irradiated CV-1 monkey kidney cell monolayers was decreased by caffeine. X-ray enhanced reactivation of UV-irradiated virus in X-irradiated monolayers (X-ray reactivation) and UV- or X-ray-inactivated capacity of the cells to support unirradiated virus plaque formation were unaffected by caffeine. The results suggest that a caffeine-sensitive process is necessary for the expression of Weigle reactivation for herpes virus. Since cafeine did not significantly affect X-ray reactivation, different mechanisms may be responsible for the expression of Weigle reactivation and X-ray reactivation.

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.

Optically transparent/colorless polyimides

NASA Technical Reports Server (NTRS)

Stclair, A. K.; Stclair, T. L.; Slemp, W.; Ezzell, K. S.

1985-01-01

Several series of linear aromatic polyimide films have been synthesized and characterized with the objective of obtaining maximum optical transparency. Two approaches have been used as part of this structure-property relationship study. The first approach is to vary the molecular structure so as to separate chromophoric centers and reduce electronic interactions between polymer chains to lower the intensity of color in the resulting polymer films. A second and concurrent approach is to perform polymerizations with highly purified monomers. Glass transition temperatures of thermally cured polyimide films are obtained by thermomechanical analysis and thermal decomposition temperatures are determined by thermogravimetric analysis. Transmittance UV-visible spectra of the polyimide films are compared to that of a commercial polyimide film. Fully imidized films are tested for solubility in common organic solvents. The more transparent films prepared in this study are evaluated for use on second-surface mirror thermal control coating systems. Lightly colored to colorless films are characterized by UV-visible spectroscopy before and after exposure to 300 equivalent solar hours UV irradiation and varying doses of 1 MeV electron irradiation. The effects of monomer purity, casting solvent and cure atmosphere on polyimide film transparency are also investigated.

Photodegradation of 4-tert-butylphenol in aqueous solution by UV-C, UV/H2O2 and UV/S2O8(2-) system.

PubMed

Wu, Yanlin; Zhu, Xiufen; Chen, Hongche; Dong, Wenbo; Zhao, Jianfu

2016-01-01

The photolytic degradation of 4-tert-butylphenol (4-t-BP) in aqueous solution was investigated using three kinds of systems: UV-C directly photodegradation system, UV/H2O2 and UV/S2O8(2-) system. Under experimental conditions, the degradation rate of 4-t-BP was in the order: UV/S2O8(2-) > UV/H2O2 > UV-C. The reaction kinetics of UV/S2O8(2-) system were thoroughly investigated. The increase of S2O8(2-) concentration enhanced the 4-t-BP degradation rate, which was inhibited when the concentration of S2O8(2-) exceeded 4.0 mM. The highest efficacy in 4-t-BP degradation was obtained at pH 6.5. The oxidation rate of 4-t-BP could be accelerated by increasing the reaction temperature and irradiation intensity. The highest rate constant (kobs = 8.4 × 10(-2) min(-1)) was acquired when the reaction temperature was 45 °C. The irradiation intensity was measured by irradiation distance, and the optimum irradiation distance was 10 cm. Moreover, the preliminary mechanism of 4-t-BP degradation was studied. The bond scission of the 4-t-BP molecule occurred by the oxidation of SO4(•-), which dimerized and formed two main primary products. Under the conditions of room temperature (25 °C ± 1 °C) and low concentration of K2S2O8 (0.5 mM), 35.4% of total organic carbon (TOC) was removed after 8.5-h irradiation. The results showed that UV/S2O8(2-) system was effective for the degradation of 4-t-BP.

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

[The effect of UV-irradiation on telomerase activity and other stress-related proteins in human lens epithelial cells].

PubMed

Wu, Zhi-hong; Zhang, Jin-song

2005-05-01

To investigate the changes and the role of telomerase activity and other stress-related proteins in the process of UV-induced DNA damage and repair in human lens epithelial cells. Human lens epithelial cells were irradiated at UV-doses 0.0 (control group) and 0.5, 1.5, 2.5, 3.5, 5.0, 7.5, 10.0 mJ/cm(2) (treated 1-7 group). Telomerase activity was determined by Telomerase Repeat Amplification Protocol-Enzyme Linked Immunosorbent Assay (TRAP-ELISA), p53, growth arrest and DNA damage inducible (GADD45), proliferating cell nuclear antigen (PCNA) and p16 protein levels were analyzed by Western blotting. Telomerase activity in control group and treated 1-7 group showed increased tendency, the differences of telomerase activity in 8 groups were significantly (P < 0.01). The expression of p53, GADD45, PCNA, p16 proteins showed increased tendency in experimental group, comparing with the control group, there were significant difference (P < 0.01). During UV-induced DNA damage and repair in human lens epithelial cells, telomerase activity was upregulated and the expression of stress-related proteins levels was increased. Upregulated telomerase activity may play both a protective and a proliferative role in human lens epithelial cells. Increased stress-related proteins level is critic in UV-induced DNA damage and repair in human lens epithelial. Increased telomerase activity is associated with increased levels of the stress-related proteins.

Effect of UV irradiation on cutaneous cicatrices: a randomized, controlled trial with clinical, skin reflectance, histological, immunohistochemical and biochemical evaluations.

PubMed

Due, Eva; Rossen, Kristian; Sorensen, Lars Tue; Kliem, Anette; Karlsmark, Tonny; Haedersdal, Merete

2007-01-01

The aim of this study was to examine the effect of ultraviolet (UV) irradiation on human cutaneous cicatrices. In this randomized, controlled study, dermal punch biopsy wounds served as a wound healing model. Wounds healed by primary or second intention and were randomized to postoperative solar UV irradiation or to no UV exposure. Evaluations after 5 and 12 weeks included blinded clinical assessments, skin reflectance measurements, histology, immunohistochemistry, and biochemical analyses of the N-terminal propeptide from procollagen-1, hydroxyproline, hydroxylysine, and proline. Twelve weeks postoperatively, UV-irradiated cicatrices healing by second intention: (i) were significantly pointed out as the most disfiguring; (ii) obtained significantly higher scores of colour, infiltration and cicatrix area; and (iii) showed significantly higher increase in skin-reflectance measurements of skin-pigmentation vs. non-irradiated cicatrices. No histological, immunohistochemical or biochemical differences were found. In conclusion, postoperative UV exposure aggravates the clinical appearance of cicatrices in humans.

Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens.

PubMed

Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun; Kang, Dong-Hyun

2016-01-01

Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm(2). At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Impact of sunscreens on preventing UVR-induced effects in nevi: in vivo study comparing protection using a physical barrier vs sunscreen.

PubMed

Carrera, Cristina; Puig-Butillè, Joan A; Aguilera, Paula; Ogbah, Zighereda; Palou, Josep; Lecha, Mario; Malvehy, Josep; Puig, Susana

2013-07-01

Sun damage is the most important environmental factor associated with malignant melanoma. To address the health threat, as well as the economic burden, primary prevention and early detection are crucial. To test the efficacy of a topical sunscreen in the prevention of UV-induced effects in nevi. Prospective study of nevi protected by sunscreen vs a physical barrier. Twenty-three nevi from 20 patients attending a referral hospital. Half of each nevus was protected by either a physical barrier or a sunscreen. Lesions were completely irradiated by a single dose of UV-B. In vivo examination before and 7 days after irradiation and histopathologic-immunopathologic evaluation after excision on the seventh day. The most frequent clinical changes after UV radiation were pigmentation, scaling, and erythema; the most frequent dermoscopic changes were increased globules/dots, blurred network, regression, and dotted vessels. Both physical barrier- and sunscreen-protected areas showed some degree of these changes. More than 30% (7) of nevi did not show any change on clinical examination, and 18% (4) had no dermoscopic change. Immunohistopathologic differences between the halves of each nevus were demonstrable even when in vivo examination detected nothing. Parakeratotic scale, increased number and activation of superficial melanocytes, and keratinocyte proliferation were the most remarkable features. The only difference between both barriers was more enhanced melanocytic activation and regression features in the sunscreen group. No phenotypic features were found to predict a specific UV-B response. Both physical barriers and sunscreens can partially prevent UV-B effects on nevi. Subclinical UV radiation effects, not always associated with visible changes, can develop even after protection. Sunscreens are not quite as effective as physical barriers in the prevention of inflammatory UV-B-induced effects.

Photocatalytic properties of Au-deposited mesoporous SiO{sub 2}–TiO{sub 2} photocatalyst under simultaneous irradiation of UV and visible light

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

Okuno, T., E-mail: t093507@edu.imc.tut.ac.jp; Kawamura, G., E-mail: gokawamura@ee.tut.ac.jp; Muto, H., E-mail: muto@ee.tut.ac.jp

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

Dosimetry of UV radiation with special respect to presence of photosensitizers or other chemical agents

NASA Astrophysics Data System (ADS)

Ronto, Gyorgyi; Csik, Gabriella; Gaspar, S.

1994-02-01

A method has been developed for measuring the biologically effective dose (BED) of solar radiation. The method applies phage T7 as a biosensor in a monitoring system. The work presents a series of dose measurements caused by direct and global irradiation. Comparisons are made of the results obtained in the same time in different places in Hungary in 1992 and 1993. A doubling of the measured BED was found which can not be explained with the ozone depletion only. An interpretation of phage T7 dose as well as transformation of the results into MED are presented. The influence of the photosensitization as an additive damage is discussed as well.

Development of an online UV-visible microspectrophotometer for a macromolecular crystallography beamline.

PubMed

Shimizu, Nobutaka; Shimizu, Tetsuya; Baba, Seiki; Hasegawa, Kazuya; Yamamoto, Masaki; Kumasaka, Takashi

2013-11-01

Measurement of the UV-visible absorption spectrum is a convenient technique for detecting chemical changes of proteins, and it is therefore useful to combine spectroscopy and diffraction studies. An online microspectrophotometer for the UV-visible region was developed and installed on the macromolecular crystallography beamline, BL38B1, at SPring-8. This spectrophotometer is equipped with a difference dispersive double monochromator, a mercury-xenon lamp as the light source, and a photomultiplier as the detector. The optical path is mostly constructed using mirrors, in order to obtain high brightness in the UV region, and the confocal optics are assembled using a cross-slit diaphragm like an iris to eliminate stray light. This system can measure optical densities up to a maximum of 4.0. To study the effect of radiation damage, preliminary measurements of glucose isomerase and thaumatin crystals were conducted in the UV region. Spectral changes dependent on X-ray dose were observed at around 280 nm, suggesting that structural changes involving Trp or Tyr residues occurred in the protein crystal. In the case of the thaumatin crystal, a broad peak around 400 nm was also generated after X-ray irradiation, suggesting the cleavage of a disulfide bond. Dose-dependent spectral changes were also observed in cryo-solutions alone, and these changes differed with the composition of the cryo-solution. These responses in the UV region are informative regarding the state of the sample; consequently, this device might be useful for X-ray crystallography.

Effect of ultraviolet light irradiation and sandblasting treatment on bond strengths between polyamide and chemical-cured resin.

PubMed

Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

2014-01-01

The aim of this study was to evaluate the effects of ultraviolet light (UV) irradiation and sandblasting treatment on the shear bond strength between polyamide and chemical-cured resin. Three types of commercial polyamides were treated using UV irradiation, sandblasting treatment, and a combining sandblasting and UV irradiation. The shear bond strength was measured and analyzed using the Kruskal-Wallis test (α=0.05). Comparing shear bond strengths without surface treatment, from 4.1 to 5.7 MPa, the UV irradiation significantly increased the shear bond strengths except for Valplast, whose shear bond strengths ranged from 5.2 to 9.3 MPa. The sandblasting treatment also significantly increased the shear bond strengths (8.0 to 11.4 MPa). The combining sandblasting and UV irradiation significantly increased the shear bond strengths (15.2 to 18.3 MPa) comparing without surface treatment. This combined treatment was considered the most effective at improving the shear bond strength between polyamide and chemical-cured resin.

Occupant UV Exposure Measurements for Upper-Room Ultraviolet Germicidal Irradiation

PubMed Central

Milonova, Sonya; Rudnick, Stephen; McDevitt, James; Nardell, Edward

2016-01-01

The threshold limit value (TLV) guideline for ultraviolet (UV) radiation specifies that irradiance measurements to ensure occupant safety be taken over an angle of 80° at the sensor. The purpose of this study was to evaluate the effect of an 80° field of view (FOV) tube on lower room UV-C irradiation measurements. Measurements were made in an experimental chamber at a height of 1.73 m with and without an FOV tube. The FOV tube reduced the lower room irradiance readings by 18-34%, a statistically significant reduction compared to the bare sensor. An 80° FOV tube should be used for lower room irradiance measurements to comply with the TLV guideline. The resulting lower readings would allow more UV-C radiation in the upper room without compromising occupant safety. More UV-C radiation in the upper room could increase efficacy of UVGI systems for reducing transmission of airborne infectious diseases. In addition, recommendations are made to standardize lower room irradiance measurement techniques. PMID:27038734

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 impact of short-term UV irradiation on grains of sensitive and tolerant cereal genotypes studied by EPR.

PubMed

Kurdziel, Magdalena; Filek, Maria; Łabanowska, Maria

2018-05-01

UV irradiation has ionisation character and leads to the generation of reactive oxygen species (ROS). The destructive character of ROS was observed among others during interaction of cereal grains with ozone and was caused by changes in structures of biomolecules leading to the formation of stable organic radicals. That effect was more evident for stress sensitive genotypes. In this study we investigated the influence of UV irradiation on cereal grains originating from genotypes with different tolerance to oxidative stress. Grains and their parts (endosperm, embryo and seed coat) of barley, wheat and oat were subjected to short-term UV irradiation. It was found that UV caused the appearance of various kinds of reactive species (O 2 -• , H 2 O 2 ) and stable radicals (semiquinone, phenoxyl and carbon-centred). Simultaneously, lipid peroxidation occurred and the organic structure of Mn(II) and Fe(III) complexes become disturbed. UV irradiation causes damage of main biochemical structures of plant tissues, the effect is more significant in sensitive genotypes. In comparison with ozone treatment, UV irradiation leads to stronger destruction of biomolecules in grains and their parts. It is caused by the high energy of UV light, facilitating easier breakage of molecular bonds in biochemical compounds. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Pollen and spores as biological recorders of past ultraviolet irradiance.

NASA Astrophysics Data System (ADS)

Fraser, Wesley; Jardine, Phillip; Lomax, Barry; Sephton, Mark; Shanahan, Timothy; Miller, Charlotte; Gosling, William

2017-04-01

Ultraviolet (UV) irradiance from the Sun is a key driver of climatic and biotic change. UV irradiance modulates processes in the stratosphere, and influences the biosphere from ecosystem-level through to the largest scale patterns of diversification and extinction. Yet our understanding of UV irradiance is limited to the present; no validated empirical method exists to reconstruct UV flux over long, geologically relevant timescales. Here, we show that a recently developed proxy for UV irradiance based on spore and pollen chemistry can be used over long (100,000 years) timescales. First, we demonstrate spatial variation in spore and pollen chemistry correlate with known latitudinal solar irradiance gradients. Second, using this relationship we provide a reconstruction of past changes in solar irradiance based on the pollen record obtained from Lake Bosumtwi in Ghana. Variations in the chemistry of grass pollen from the Lake Bosumtwi record show a link to multiple orbital precessional cycles (19-21,000 years). By providing a unique, local proxy for broad spectrum solar irradiance, the chemical analysis of spores and pollen offers unprecedented opportunities to decouple solar variability, climate and vegetation change through geologic time and a new proxy with which to probe the Earth system.

Ultraviolet Irradiation of Blood: "The Cure That Time Forgot"?

PubMed

Hamblin, Michael R

2017-01-01

Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma and even poliomyelitis. The early studies were carried out by several physicians in USA and published in the American Journal of Surgery. However with the development of antibiotics, UBI use declined and it has now been called "the cure that time forgot". Later studies were mostly performed by Russian workers and in other Eastern countries and the modern view in Western countries is that UBI remains highly controversial.This chapter discusses the potential of UBI as an alternative approach to current methods used to treat infections, as an immune-modulating therapy and as a method for normalizing blood parameters. No resistance of microorganisms to UV irradiation has been reported, and multi-antibiotic resistant strains are as susceptible as their wild-type counterparts. Low and mild doses of UV kill microorganisms by damaging the DNA, while any DNA damage in host cells can be rapidly repaired by DNA repair enzymes. However the use of UBI to treat septicemia cannot be solely due to UV-mediated killing of bacteria in the blood-stream, as only 5-7% of blood volume needs to be treated with UV to produce the optimum benefit. UBI may enhance the phagocytic capacity of various phagocytic cells (neutrophils and dendritic cells), inhibit lymphocytes, and oxidize blood lipids. The oxidative nature of UBI may have mechanisms in common with ozone therapy and other oxygen therapies. There may be some similarities to extracorporeal photopheresis (ECP) using psoralens and UVA irradiation. However there are differences between UBI and ECP in that UBI tends to stimulate the immune system, while ECP tends to be immunosuppressive. With the recent emergence of bacteria that are resistant to all known antibiotics, UBI should be more investigated as an alternative approach to infections, and as an immune-modulating therapy.

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

NASA Astrophysics Data System (ADS)

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

1998-11-01

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

The effect of titanium dioxide (TiO2) nano-objects, and their aggregates and agglomerates greater than 100nm (NOAA) on microbes under UV irradiation.

PubMed

Yamada, Ikuho; Nomura, Kazuki; Iwahashi, Hitoshi; Horie, Masanori

2016-01-01

Today, nanoparticles are used in many products. One of the most common nanoparticles is titanium dioxide (TiO2). These particles generate reactive oxygen species (ROS) upon UV irradiation. Although nanoparticles are very useful in many products, there are concerns about their biological and ecological effects when released into the environment. Thus, it was assessed that the effect of TiO2 nano-objects, and their aggregates and agglomerates greater than 100nm (NOAA) on microbes under UV irradiation by using Escherichia coli and Saccharomyces cerevisiae. ROS generation was evaluated by adding TiO2 nanoparticles and methylene blue to distilled water. We also assessed growth inhibition by adding TiO2 nanoparticles and microbes in minimal agar medium. Moreover, microbial inactivation was assessed by adding TiO2 nanoparticles and microbes to PBS. Upon UV irradiation, TiO2-NOAAs decomposed methylene blue and generated ROS. TiO2-NOAAs also decomposed methylene blue in minimal agar medium under UV irradiation; however, they did not inhibit microbial growth. Surprisingly, TiO2-NOAAs in the medium protect microbes from UV irradiation as colony formation was observed only near TiO2-NOAAs. In PBS, TiO2-NOAAs did not inactivate microbes but instead protected microbes from lethal UV irradiation. These results suggest that the amount of ROS generated by TiO2-NOAAs is not enough to inactivate microbes. In fact, our results suggest that TiO2-NOAAs may protect microbes from UV irradiations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Demonstration of UV LED versatility when paired with molded UV transmitting glass optics to produce unique irradiance patterns

NASA Astrophysics Data System (ADS)

Jasenak, Brian

2017-02-01

Ultraviolet light-emitting diode (UV LED) adoption is accelerating; they are being used in new applications such as UV curing, germicidal irradiation, nondestructive testing, and forensic analysis. In many of these applications, it is critically important to produce a uniform light distribution and consistent surface irradiance. Flat panes of fused quartz, silica, or glass are commonly used to cover and protect UV LED arrays. However, they don't offer the advantages of an optical lens design. An investigation was conducted to determine the effect of a secondary glass optic on the uniformity of the light distribution and irradiance. Glass optics capable of transmitting UV-A, UV-B, and UV-C wavelengths can improve light distribution, uniformity, and intensity. In this work, two simulation studies were created to illustrate distinct irradiance patterns desirable for potential real world applications. The first study investigates the use of a multi-UV LED array and optic to create a uniform irradiance pattern on the flat two dimensional (2D) target surface. The uniformity was improved by designing both the LED array and molded optic to produce a homogenous pattern. The second study investigated the use of an LED light source and molded optic to improve the light uniformity on the inside of a canister. The case study illustrates the requirements for careful selection of LED based on light distribution and subsequent design of optics. The optic utilizes total internal reflection to create optimized light distribution. The combination of the LED and molded optic showed significant improvement in uniformity on the inner surface of the canister. The simulations illustrate how the application of optics can significantly improve UV light distribution which can be critical in applications such as UV curing and sterilization.

Accuracy Assessments and Validation of an Expanded UV Irradiance Database from Satellite Total Ozone Mapping Spectrometer (TOMS)

NASA Technical Reports Server (NTRS)

Krotkov, N. A.; Herman, J.; Fioletov, V.; Seftor, C.; Larko, D.; Vasilkov, A.

2004-01-01

The TOMS UV irradiance database (1978 to 2000) has been expanded to include 5 new products (noon irradiance at 305, 310, 324, and 380 nm, and noon erythemal-weighted irradiance), in addition to the existing erythemal daily exposure, which permit direct Comparisons with ground-based measurements from UV spectrometers. Sensitivity studies are conducted to estimate uncertainties of the new TOMS UV irradiance data due to algorithm apriori assumptions. Comparisons with Brewer spectrometers as well as filter radiometers are used to review of the sources of known errors. Inability to distinguish between snow and cloud cover using only TOMS data results in large errors in estimating surface UV using snow climatology. A correction is suggested for the case when the regional snow albedo is known from an independent source. The summer-time positive bias between TOMS UV estimations and Brewer measurements can be seen at all wavelengths. This suggests the difference is not related to ozone absorption effects. We emphasize that uncertainty of boundary layer UV aerosol absorption properties remains a major source of error in modeling UV irradiance in clear sky conditions. Neglecting aerosol absorption by the present TOMS algorithm results in a positive summertime bias in clear-sky UV estimations over many locations. Due to high aerosol variability the bias is strongly site dependent. Data from UV-shadow-band radiometer and well-calibrated CIMEL sun-sky radiometer are used to quantify the bias at NASA/GSFC site in Greenbelt, MD. Recommendations are given to enable potential users to better account for local conditions by combining standard TOMS UV data with ancillary ground measurements.

Protective properties of ginsenoside Rb1 against UV-B radiation-induced oxidative stress in human dermal keratinocytes.

PubMed

Oh, Sun-Joo; Kim, Kyunghoon; Lim, Chang-Jin

2015-06-01

Ginsenosides, also known as ginseng saponins, are responsible for most pharmacological effect of ginseng. Ginsenoside Rb1 (Rb1) exerts a variety of pharmacological properties, including anti-inflammatory, antistress, anti-aging and anti-neurodegenerative activities. The aim of the present work was to assess the skin anti-photoaging properties of Rb1 in human dermal keratinocyte HaCaT cells. The anti-photoaging activity was evaluated by analyzing the levels of reactive oxygen species (ROS) and matrix metalloproteinases (MMPs) as well as cell viability for HaCaT cells under UV-B irradiation. Rb1 was able to suppress the ROS levels which were elevated under UV-B irradiation, and unable to influence cellular survival in UV-B-irradiated HaCaT cells. Rb1 diminished the enhancement of MMP-2 gelatinolytic activity in conditioned medium, which corresponded with the decreased MMP-2 protein levels in both conditioned medium and cellular lysate prepared from UV-B-irradiated HaCaT cultures. Rb1 could restore the total glutathione (GSH) and superoxide dismutase (SOD) activity diminished in UV-B-irradiated HaCaT cells. Ginsenoside Rb1 possesses skin anti-photoaging properties through scavenging ROS and decreasing MMP-2 levels possibly by enhancing antioxidant activity in keratinocytes under UV-B irradiation.

Ultraviolet light protection by a sunscreen prevents interferon-driven skin inflammation in cutaneous lupus erythematosus.

PubMed

Zahn, Sabine; Graef, Medina; Patsinakidis, Nikolaos; Landmann, Aysche; Surber, Christian; Wenzel, Joerg; Kuhn, Annegret

2014-07-01

Irradiation with ultraviolet (UV) light is an important exacerbating factor in cutaneous lupus erythematosus (CLE) and induces various effects in the skin of patients with the disease, such as cell death and inflammation. Recently, we demonstrated the ability of a broad-spectrum sunscreen to prevent UV-induced damage both in patients with CLE and healthy controls (HCs). The aim of this study was to evaluate whether the UV-dependent activation of interferon (IFN)-driven inflammation in CLE can also be prevented by application of the sunscreen. In 20 patients with different subtypes of CLE and 10 HCs, defined areas on the upper back were treated with a broad-spectrum liposomal sunscreen 20 min prior to a combined standardized UVA/UVB irradiation. Immunohistological analyses using antibodies directed against MxA, CD11c, CD123 and CD68 were performed from skin biopsies taken from areas before UV irradiation as well as from sunscreen-treated and sunscreen-untreated areas 24 and 72 h after UV irradiation. The expression of MxA was completely prevented by the sunscreen applied prior to UV irradiation in CLE patients and HCs. Additionally, sunscreen protection significantly diminished the number of the CD11c- and CD123-positive dendritic cells, which are suggested to be a major source of type I/III IFNs, in UV-irradiated skin of patients with CLE. Moreover, the application of the sunscreen prevented the increase in CD68-positive macrophages in both groups 72 h after UV irradiation. The data of this study demonstrate that UV protection reduces lesional tissue damage and inhibits the typical IFN-driven inflammatory response in CLE. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Study the Characterization of Spectral Absorbance on Irradiated Milk Protein

NASA Astrophysics Data System (ADS)

Fohely, F.; Suardi, N.

2018-04-01

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

Physico-chemical behaviour of β irradiated plastic materials currently used as packagings and medical products

NASA Astrophysics Data System (ADS)

Yagoubi, N.; Baillet, A.; Pellerin, F.; Ferrier, D.

1995-11-01

The combined chromatographic technics and thermal analysis constitute an informative methodology for studying the modifications which could occur following a radiotreatment of plastic material at different doses (25 to 100 kGy). Several plastic materials used as packagings (PVC, PE, PS) were investigated. SEC method coupled with UV and DDL detections was applied to document any changes in molecular weight distribution. Reticulation and scission were the main observed degradation phenomena. These structural modifications were supported by TGA data, while the DSC provided information on modifications in crystallinity. In addition, RP-HPLC was carried out for the evaluation of the radiochemical behaviour of the additives and monomers. Firstly we demonstrated the degradation of high molecular weight phenolic antioxidants in BHT within the PEVA. Secondly, the modifications of amino 6 caproic acid and ɛ caprolactam, present in polyamid 6, depend on the irradiation doses.

UV scale calibration transfer from an improved pyroelectric detector standard to field UV-A meters and 365 nm excitation sources

NASA Astrophysics Data System (ADS)

Eppeldauer, G. P.; Podobedov, V. B.; Cooksey, C. C.

2017-05-01

Calibration of the emitted radiation from UV sources peaking at 365 nm, is necessary to perform the ASTM required 1 mW/cm2 minimum irradiance in certain military material (ships, airplanes etc) tests. These UV "black lights" are applied for crack-recognition using fluorescent liquid penetrant inspection. At present, these nondestructive tests are performed using Hg-lamps. Lack of a proper standard and the different spectral responsivities of the available UV meters cause significant measurement errors even if the same UV-365 source is measured. A pyroelectric radiometer standard with spectrally flat (constant) response in the UV-VIS range has been developed to solve the problem. The response curve of this standard determined from spectral reflectance measurement, is converted into spectral irradiance responsivity with <0.5% (k=2) uncertainty as a result of using an absolute tie point from a Si-trap detector traceable to the primary standard cryogenic radiometer. The flat pyroelectric radiometer standard can be used to perform uniform integrated irradiance measurements from all kinds of UV sources (with different peaks and distributions) without using any source standard. Using this broadband calibration method, yearly spectral calibrations for the reference UV (LED) sources and irradiance meters is not needed. Field UV sources and meters can be calibrated against the pyroelectric radiometer standard for broadband (integrated) irradiance and integrated responsivity. Using the broadband measurement procedure, the UV measurements give uniform results with significantly decreased uncertainties.

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

NASA Astrophysics Data System (ADS)

Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

2015-09-01

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

Study of the optical properties and the carbonaceous clusters in DAM-ADC solid state nuclear track detectors

NASA Astrophysics Data System (ADS)

Rammah, Y. S.; Abdalla, A. M.

2017-12-01

The optical properties of DAM-ADC solid state nuclear track detectors (SSNTDs) were investigated. Samples of DAM-ADC detector were irradiated at room temperature with gamma doses in the range of 100-500 kGy using 1.25 MeV 60Co source of dose rate 4 kGy/h. The optical characterization of these detectors have been studied through the measurements of UV-visible absorption spectra of blank and γ- irradiated samples. The optical energy band gaps, Eg for the detectors were obtained from the direct and the indirect allowed transitions in K-space using two methods (Tauc's model and absorption spectrum fitting (ASF) method). The absorbance of DAM-ADC detector was found to increase with increasing of the gamma absorbed dose. The width of the tail of localized states in the band gap, Eu was evaluated with the Urbach's method. The number of carbon atoms per conjugated length (N), the number of carbon atoms per cluster (M), and refractive index (n) for the present samples were determined. Both of the direct and the indirect band gaps of DAM-ADC detector decrease with increasing of the gamma absorbed dose. Urbach's energy decreased significantly for the detector. An increase in N, M, and n with increasing of the gamma absorbed dose was noticed. Results shed light on the effect of gamma irradiations of DAM-ADC SSNTDs to suitable industrial applications and to modify the optical properties through gamma-induced modifications of the polymer structure.

Parameterization of daily solar global ultraviolet irradiation.

PubMed

Feister, U; Jäkel, E; Gericke, K

2002-09-01

Daily values of solar global ultraviolet (UV) B and UVA irradiation as well as erythemal irradiation have been parameterized to be estimated from pyranometer measurements of daily global and diffuse irradiation as well as from atmospheric column ozone. Data recorded at the Meteorological Observatory Potsdam (52 degrees N, 107 m asl) in Germany over the time period 1997-2000 have been used to derive sets of regression coefficients. The validation of the method against independent data sets of measured UV irradiation shows that the parameterization provides a gain of information for UVB, UVA and erythemal irradiation referring to their averages. A comparison between parameterized daily UV irradiation and independent values of UV irradiation measured at a mountain station in southern Germany (Meteorological Observatory Hohenpeissenberg at 48 degrees N, 977 m asl) indicates that the parameterization also holds even under completely different climatic conditions. On a long-term average (1953-2000), parameterized annual UV irradiation values are 15% and 21% higher for UVA and UVB, respectively, at Hohenpeissenberg than they are at Potsdam. Daily global and diffuse irradiation measured at 28 weather stations of the Deutscher Wetterdienst German Radiation Network and grid values of column ozone from the EPTOMS satellite experiment served as inputs to calculate the estimates of the spatial distribution of daily and annual values of UV irradiation across Germany. Using daily values of global and diffuse irradiation recorded at Potsdam since 1937 as well as atmospheric column ozone measured since 1964 at the same site, estimates of daily and annual UV irradiation have been derived for this site over the period from 1937 through 2000, which include the effects of changes in cloudiness, in aerosols and, at least for the period of ozone measurements from 1964 to 2000, in atmospheric ozone. It is shown that the extremely low ozone values observed mainly after the eruption of Mt. Pinatubo in 1991 have substantially enhanced UVB irradiation in the first half of the 1990s. According to the measurements and calculations, the nonlinear long-term changes observed between 1968 and 2000 amount to +4%, ..., +5% for annual global irradiation and UVA irradiation mainly because of changing cloudiness and + 14%, ..., +15% for UVB and erythemal irradiation because of both changing cloudiness and decreasing column ozone. At the mountain site, Hohenpeissenberg, measured global irradiation and parameterized UVA irradiation decreased during the same time period by -3%, ..., -4%, probably because of the enhanced occurrence and increasing optical thickness of clouds, whereas UVB and erythemal irradiation derived by the parameterization have increased by +3%, ..., +4% because of the combined effect of clouds and decreasing ozone. The parameterizations described here should be applicable to other regions with similar atmospheric and geographic conditions, whereas for regions with significantly different climatic conditions, such as high mountainous areas and arctic or tropical regions, the representativeness of the regression coefficients would have to be approved. It is emphasized here that parameterizations, as the one described in this article, cannot replace measurements of solar UV radiation, but they can use existing measurements of solar global and diffuse radiation as well as data on atmospheric ozone to provide estimates of UV irradiation in regions and over time periods for which UV measurements are not available.

UV irradiation study of a tripeptide isolated in an argon matrix: A tautomerism process evidenced by infrared and X-ray photoemission spectroscopies

NASA Astrophysics Data System (ADS)

Mateo-Marti, E.; Pradier, C. M.

2013-05-01

Matrix isolation is a powerful tool for studying photochemical processes occurring in isolated molecules. In this way, we characterized the chemical modifications occurring within a tri peptide molecule, IGF, when exposed to the influence of Ultraviolet (UV) irradiation. This paper first describes the successful formation of the tripeptide (IGF) argon matrix under vacuum conditions, followed by the in situ UV irradiation and characterization of the molecular matrix reactivity after UV-irradiation. These studies have been performed by combining two complementary spectroscopic techniques, Fourier-Transform Reflexion Absorption Spectroscopy (FT-IRRAS) and X-ray Photoelectron Spectroscopy (XPS). The IR spectra of the isolated peptide-matrix, before and after UV irradiation, revealed significant differences that could be associated either to a partial deprotonation of the molecule or to a tautomeric conversion of some amide bonds to imide ones on some peptide molecules. XPS analyses undoubtedly confirmed the second hypothesis; the combination of IRRAS and XPS results provide evidence that UV irradiation of peptides induces a chemical reaction, namely a shift of the double bond, meaning partial conversion from amide tautomer into an imidic acid tautomer.

Decoloration Kinetics of Waste Cooking Oil by 60Co γ-ray/H2O2

NASA Astrophysics Data System (ADS)

Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng

2016-03-01

In order to decolorize, waste cooking oil, a dark red close to black solution from homes and restaurants, was subjected to 60Co γ-ray/H2O2 treatment. By virtue of UV/Vis spectrophotometric method, the influence of Gamma irradiation to decoloration kinetics and rate constants of the waste cooking oil in the presence of H2O2 was researched. In addition, the influence of different factors such as H2O2 concentration and irradiation dose on the decoloration rate of waste cooking oil was investigated. Results indicated that the decoloration kinetics of waste cooking oil conformed to the first-order reaction. The decoloration rate increased with the increase of irradiation dose and H2O2 concentration. Saponification analysis and sensory evaluation showed that the sample by 60Co γ-ray/H2O2 treatment presented better saponification performance and sensory score. Furthermore, according to cost estimate, the cost of the 60Co γ-ray/H2O2 was lower and more feasible than the H2O2 alone for decoloration of waste cooking oil.

Feasibility of Ultraviolet Light Emitting Diodes as an Alternative Light Source for Photocatalysis

NASA Technical Reports Server (NTRS)

Levine, Langanf H.; Richards, Jeffrey T.; Soler, Robert; Maxik, Fred; Coutts, Janelle; Wheeler, Raymond M.

2011-01-01

The objective of this study was to determine whether ultraviolet light emitting diodes (UV-LEDs) could serve as an alternative photon source efficiently for heterogeneous photocatalytic oxidation (PCO). An LED module consisting of 12 high-power UV-A LEDs was designed to be interchangeable with a UV-A fluorescent black light blue (BLB) lamp in a Silica-Titania Composite (STC) packed bed annular reactor. Lighting and thermal properties were characterized to assess the uniformity and total irradiant output. A forward current of (I(sub F)) 100 mA delivered an average irradiance of 4.0 m W cm(exp -2), which is equivalent to the maximum output of the BLB, but the irradiance of the LED module was less uniform than that of the BLB. The LED- and BLB-reactors were tested for the oxidization of 50 ppmv ethanol in a continuous flow-through mode with 0.94 sec space time. At the same irradiance, the UV-A LED reactor resulted in a lower PCO rate constant than the UV-A BLB reactor (19.8 vs. 28.6 nM CO2 sec-I), and consequently lower ethanol removal (80% vs. 91%) and mineralization efficiency (28% vs. 44%). Ethanol mineralization increased in direct proportion to the irradiance at the catalyst surface. This result suggests that reduced ethanol mineralization in the LED- reactor could be traced to uneven irradiance over the photocatalyst, leaving a portion of the catalyst was under-irradiated. The potential of UV-A LEDs may be fully realized by optimizing the light distribution over the catalyst and utilizing their instantaneous "on" and "off' feature for periodic irradiation. Nevertheless, the current UV-A LED module had the same wall plug efficiency (WPE) of 13% as that of the UV-A BLB. These results demonstrated that UV-A LEDs are a viable photon source both in terms of WPE and PCO efficiency.

Development of high power UV irradiance meter calibration device

NASA Astrophysics Data System (ADS)

Xia, Ming; Gao, Jianqiang; Yin, Dejin; Li, Tiecheng

2016-09-01

With the rapid development of China's economy, many industries have more requirements for UV light applications, such as machinery manufacturing, aircraft manufacturing using high power UV light for detection, IT industry using high power UV light for curing component assembly, building materials, ink, paint and other industries using high power UV light for material aging test etc. In these industries, there are many measuring instruments for high power UV irradiance which are need to traceability. But these instruments are mostly imported instruments, these imported UV radiation meter are large range, wide wavelength range and high accuracy. They have exceeded our existing calibration capability. Expand the measuring range and improve the measurement accuracy of UV irradiance calibration device is a pressing matter of the moment. The newly developed high power UV irradiance calibration device is mainly composed of high power UV light, UV filter, condenser, UV light guide, optical alignment system, standard cavity absolute radiometer. The calibration device is using optical alignment system to form uniform light radiation field. The standard is standard cavity absolute radiometer, which can through the electrical substitution method, by means of adjusting and measuring the applied DC electric power at the receiver on a heating wire, which is equivalent to the thermo-electromotive force generated by the light radiation power, to achieve absolute optical radiation measurement. This method is the commonly used effective method for accurate measurement of light irradiation. The measuring range of calibration device is (0.2 200) mW/cm2, and the uncertainty of measurement results can reached 2.5% (k=2).

Retrieval of the aerosol optical thickness from UV global irradiance measurements

NASA Astrophysics Data System (ADS)

Costa, M. J.; Salgueiro, V.; Bortoli, D.; Obregón, M. A.; Antón, M.; Silva, A. M.

2015-12-01

The UV irradiance is measured at Évora since several years, where a CIMEL sunphotometer integrated in AERONET is also installed. In the present work, measurements of UVA (315 - 400 nm) irradiances taken with Kipp&Zonen radiometers, as well as satellite data of ozone total column values, are used in combination with radiative transfer calculations, to estimate the aerosol optical thickness (AOT) in the UV. The retrieved UV AOT in Évora is compared with AERONET AOT (at 340 and 380 nm) and a fairly good agreement is found with a root mean square error of 0.05 (normalized root mean square error of 8.3%) and a mean absolute error of 0.04 (mean percentage error of 2.9%). The methodology is then used to estimate the UV AOT in Sines, an industrialized site on the Atlantic western coast, where the UV irradiance is monitored since 2013 but no aerosol information is available.

Validation of large-scale, monochromatic UV disinfection systems for drinking water using dyed microspheres.

PubMed

Blatchley, E R; Shen, C; Scheible, O K; Robinson, J P; Ragheb, K; Bergstrom, D E; Rokjer, D

2008-02-01

Dyed microspheres have been developed as a new method for validation of ultraviolet (UV) reactor systems. When properly applied, dyed microspheres allow measurement of the UV dose distribution delivered by a photochemical reactor for a given operating condition. Prior to this research, dyed microspheres had only been applied to a bench-scale UV reactor. The goal of this research was to extend the application of dyed microspheres to large-scale reactors. Dyed microsphere tests were conducted on two prototype large-scale UV reactors at the UV Validation and Research Center of New York (UV Center) in Johnstown, NY. All microsphere tests were conducted under conditions that had been used previously in biodosimetry experiments involving two challenge bacteriophage: MS2 and Qbeta. Numerical simulations based on computational fluid dynamics and irradiance field modeling were also performed for the same set of operating conditions used in the microspheres assays. Microsphere tests on the first reactor illustrated difficulties in sample collection and discrimination of microspheres against ambient particles. Changes in sample collection and work-up were implemented in tests conducted on the second reactor that allowed for improvements in microsphere capture and discrimination against the background. Under these conditions, estimates of the UV dose distribution from the microspheres assay were consistent with numerical simulations and the results of biodosimetry, using both challenge organisms. The combined application of dyed microspheres, biodosimetry, and numerical simulation offers the potential to provide a more in-depth description of reactor performance than any of these methods individually, or in combination. This approach also has the potential to substantially reduce uncertainties in reactor validation, thereby leading to better understanding of reactor performance, improvements in reactor design, and decreases in reactor capital and operating costs.

Checking ozone amounts by measurements of UV-irradiances

NASA Technical Reports Server (NTRS)

Seckmeyer, Gunther; Kettner, Christiane; Thiel, Stephen

1994-01-01

Absolute measurements of UV-irradiances in Germany and New Zealand are used to determine the total amounts of ozone. UV-irradiances measured and calculated for clear skies and for solar zenith angles less than 60 deg generally show a good accordance. The UVB-irradiances, however, show that the actual Dobson values are about 5 percent higher in Germany and about 3 percent higher in New Zealand compared to those obtained by our method. Possible reasons for these deviations are discussed.

Bioconvertible vitamin antioxidants improve sunscreen photoprotection against UV-induced reactive oxygen species.

PubMed

Hanson, Kerry M; Clegg, Robert M

2003-01-01

The ability of sunscreens and antioxidants to deactivate highly destructive reactive oxygen species in human skin has remained inconclusive. Two-photon fluorescence imaging microscopy was used to determine the effect of sunscreen/antioxidant combinations upon UV-induced ROS generation in ex vivo human skin. A sunscreen combination containing octylmethoxycinnamate (Parsol MCX) and avobenzone (Parsol 1789) at SPF 8 and SPF 15 was tested for its ability to prevent UV radiation from generating ROS in the viable epidermal strata of ex vivo human skin. A UV dose equivalent to two hours of North American solar UV was used to irradiate the skin. Each sunscreen reduced the amount of ROS induced in the viable strata by a value consistent with the SPF level. UV photons that were not absorbed/scattered by the sunscreen formulations generated ROS within the viable epidermal layers. The addition of the bioconvertible antioxidants vitamin E acetate and sodium ascorbyl phosphate (STAY-C 50) improves photoprotection by converting to vitamins E and C, respectively, within the skin. The bioconversion forms an antioxidant reservoir that deactivates the ROS generated (within the strata granulosum, spinosum, and basale) by the UV photons that the sunscreens do not block in the stratum corneum.

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

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

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

1982-02-01

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

Modulation of in vitro transformation and the early and late modes of DNA replication of uv-irradiation Syrian hamster cells by caffeine

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

Doniger, J.; DiPaolo, J.A.

1981-09-01

The effect of caffeine on post-uv DNA replication was studied to determine its relevance to carcinogenesis. The level of uv-induced transformed colonies of Syrian hamster embryo cells (HEC) was increased up to fivefold when caffeine was added to cells between 0 and 6 h post-uv. The greatest increase was observed when the interval between uv irradiation and caffeine addition was 4 h. Two modes of DNA replication occurred after uv irradiation. During the early mode (0 to 3 h post-uv) the size of nascent strands, as measured by alkaline sucrose sedimentation, was smaller than those in nonirradiated cells, whereas duringmore » the late mode they recovered to normal size. Caffeine inhibited the rate of elongation of nascent strands during the early mode. When caffeine was added immediately after uv irradiation, the conversion of the early mode to the late mode was inhibited. Studies on the effects of caffeine have now been extended to the late mode. While caffeine has little effect with the fd elements beginning from the 10th day after irradiation is connected with their proliferation but not with the migration out from lymphoid organs.« less

Pyruvate kinase M2 interacts with DNA damage-binding protein 2 and reduces cell survival upon UV irradiation

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

Xie, Xiao; Wang, Mingsong; Mei, Ju, E-mail: jumei_xinhua@163.com

Pyruvate Kinase M2 (PKM2) is highly expressed in many solid tumors and associated with metabolism reprogramming and proliferation of tumors. Here, we report that PKM2 can bind to DNA Damage-Binding Protein 2 (DDB2), which is necessary for global nucleotide excision repair of UV induced DNA damage. The binding is promoted by UV irradiation and K433 acetylation of PKM2. Over expression of PKM2 facilitates phosphorylation of DDB2 and impairs DDB2-DDB1 binding. Furthermore, knocking down of PKM2 increases cell survival upon UV irradiation, while over expression of PKM2 reduces cell survival and over expression of DDB2-DDB1 reverts this effect. These results revealmore » a previously unknown regulation of PKM2 on DDB2 and provide a possible mechanism for UV induced tumorigenesis. - Highlights: • PKM2 interacts with DDB2. • UV irradiation increases PKM2-DDB2 binding via up regulation of PKM2 K433 acetylation. • PKM2 facilitates DDB2 phosphorylation and impairs DDB2-DDB1 binding. • PKM2 reduces cell survival upon UV irradiation.« less

The efficacy of corneal cross-linking shows a sudden decrease with very high intensity UV light and short treatment time.

PubMed

Wernli, Jeremy; Schumacher, Silvia; Spoerl, Eberhard; Mrochen, Michael

2013-02-01

Standard treatment in cases of progressive keratectasia is UV-triggered corneal cross-linking. For irradiances larger than 10 mW/cm(2) and treatment times below 10 minutes, the scientific proof of a biomechanical strengthening effect is insufficient. The authors investigated the biomechanical strengthening of ex vivo corneal tissue treated with irradiances between 3 mW/cm(2) and 90 mW/cm(2) and illumination times from 30 minutes to 1 minute, respectively. A total of 100 porcine eyes received riboflavin + UV treatment (constant irradiation dose of 5.4 J/cm(2)) with different intensities and illumination times and were randomly assigned into 10 groups. A control group (80 eyes) was not irradiated but underwent the same treatment otherwise. Young's modulus at 10% strain was determined for each strip after uniaxial stress-strain measurement. A Kruskal-Wallis test was used for statistical analysis. A statistically significant difference (α = 0.01) was found between the median value of Young's modulus of the treatment groups up to 45 mW/cm(2) (illumination times from 30 minutes to 2 minutes) compared with the control group. There was no statistically significant difference between the treatment groups from 50 mW/cm(2) up to 90 mW/cm(2) (illumination times of less than 2 minutes) and the control group. The ex vivo results of corneal cross-linking performed in porcine corneas show that the Bunsen-Roscoe reciprocity law is only valid for illumination intensities up to 40 to 50 mW/cm(2) and illumination times of more than 2 minutes. Further experiments are necessary to validate these results for in vivo human corneal tissue. Additionally, safety aspects at high intensities must be investigated.

Solar-simulating irradiation of the skin of human subjects in vivo produces Langerhans cell responses distinct from irradiation ex vivo and in vitro.

PubMed

Laihia, J K; Jansen, C T

2000-08-01

It has been postulated that Langerhans cells (LC) provide tolerogenic signals in the local impairment of cutaneous immune functions and antigen-specific tolerance induced by UV radiation. Studies in vitro and ex vivo have indicated that UV radiation may down-regulate the expression of costimulatory molecules on LC, leading to reduced antigen-presenting function. In contrast, we recently observed an up-regulatory stage in the number of human epidermal LC with induced expression of B7 costimulatory molecules 12-24 h after solar-simulating UV radiation (SSR) in vivo. To examine the apparent discrepancy between the observed human LC responses in vitro, ex vivo and in vivo, we compared the three protocols in a parallel fashion. The intact skin as well as skin explants and epidermal cell suspensions from the same individuals were irradiated with a single erythematogenic dose of SSR. The expression of cell surface markers in the epidermal cells was analysed with flow cytometry 24 h later. The number of CD1a+/HLA-DR+ LC increased post-SSR in vivo by a factor of 2.8+/-0.4, whereas in irradiated skin explants ex vivo or in cell suspensions in vitro, reduced numbers were seen. HLA-DR expression intensities were found to have increased on DR+ and CD1a+/DR+ cells in vivo. Similarly, SSR induced B7-2 (CD86) expression in CD1a+ cells significantly in vivo (P=0.031) but reduced the expression ex vivo or in vitro. We conclude that the early up-regulatory stage of human LC number and membrane markers, recorded at 24 h after a single exposure to SSR, is exclusively an in vivo phenomenon.

Intensities of Incident and Transmitted Ultraviolet-A Rays through Gafchromic Films

PubMed Central

Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Noguchi, Atsushi; Yabunaka, Kouichi

2017-01-01

Gafchromic films have been applied to X-ray dosimetry in diagnostic radiology. To correct nonuniformity errors in Gafchromic films, X-rays in the double-exposure technique can be replaced with ultraviolet (UV)-A rays. Intensities of the incident and transmitted UV-A rays were measured. However, it is unclear whether the chemical color change of Gafchromic films affects the UV-A transmission intensity. Gafchromic EBT3 films were suitable to be used in this study because non-UV protection layers are present on both sides of the film. The film is placed between UV-A ray light-emitting diodes and a probe of a UV meter. Gafchromic EBT3 films were irradiated by UV-A rays for up to 60 min. Data for analysis were obtained in the subsequent 60 min. Images from before and after UV-A irradiation were subtracted. When using 375 nm UV-A, the mean ± standard deviation (SD) of the pixel values in the subtracted image was remarkably high (11,194.15 ± 586.63). However, the UV-A transmissivity remained constant throughout the 60 min irradiation period. The mean ± SD UV-A transmission intensity was 184.48 ± 0.50 μm/cm2. Our findings demonstrate that color density changes in Gafchromic EBT3 films do not affect their UV-A transmission. Therefore, Gafchromic films were irradiated by UV-A rays as a preexposure. PMID:28706354

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

UV induced foot duplication in regenerating hydra is mediated by metalloproteinases and modulation of the Wnt pathway.

PubMed

Krishnapati, Lakshmi-Surekha; Londhe, Rohini; Deoli, Vaishali; Barve, Apurva; Ghaskadbi, Saroj; Ghaskadbi, Surendra

2016-01-01

We have shown earlier that irradiation with UV induces duplication of foot in regenerating middle pieces of hydra. The present study was undertaken to elucidate the underlying mechanism(s) leading to this curious phenomenon. UV irradiation induced duplicated foot in about 30% of regenerating middle pieces. Metalloproteinases are important in foot formation, while Wnt pathway genes are important in head formation in hydra. The effect of UV irradiation on expression of these genes was studied by in situ hybridization and q-PCR. In whole polyps and middle pieces, UV irradiation led to up-regulation of HMP2 and HMMP, the two metalloproteinases involved in foot formation in hydra. HMP2 expression was significantly increased starting from 30 min post exposure to UV at 254 nm (500 J/m(2)), while HMMP showed significant up-regulation 6 h post UV exposure onwards. In middle pieces, increased expression of both metalloproteinases was observed only at 48 h. In whole polyps as well as in middle pieces, expression of Wnt3 and β-catenin was detected within 30 min of UV exposure and was accompanied by up-regulation of GSK3β, DKK3 and DKK1/2/4, inhibitors of the Wnt pathway. These conditions likely lead to inactivation of Wnt signaling. We therefore conclude that duplication of foot due to UV irradiation in regenerating middle pieces of hydra is a combined effect of up-regulation of metalloproteinases and inactivation of the Wnt pathway. Our results suggest that UV irradiation can be employed as a tool to understand patterning mechanisms during foot formation in hydra.

Reactive oxygen species spermine metabolites generated from amine oxidases and radiation represent a therapeutic gain in cancer treatments.

PubMed

Amendola, Roberto; Cervelli, Manuela; Fratini, Emiliano; Sallustio, Davide E; Tempera, Giampiero; Ueshima, Taichi; Mariottini, Paolo; Agostinelli, Enzo

2013-09-01

The most frequent interventions in cancer therapy are currently the destruction of cells by irradiation or administration of drugs both able to induce radical formation and toxic metabolites by enzyme-catalyzed reactions. The aim of this study was to determine the cell viability of cells undergoing a DNA damage threshold accomplished by ROS overproduction via both ectopic expression of murine spermine oxidase (mSMOX) and bovine serum amine oxidase (BSAO) enzymes. Low dose of X-irradiation delivers a challenging dose of damage as evaluated in proficient Chinese hamster AA8 cell line and both deficient transcription-coupled nucleotide excision repair (NER) UV61 cells and deficient base excision repair (BER) EM9 cells, at 6 and 24 h after exposure. The priming dose of ROS overexposure by mSMOX provokes an adaptive response in N18TG2, AA8 and EM9 cell lines at 24 h. Interestingly, in the UV61 cells, ROS overexposure by mSMOX delivers an earlier adaptive response to radiation. The enzymatic formation of toxic metabolites has mainly been investigated on wild-type (WT) and multidrug-resistant (MDR) cancer cell lines, using and spermine as substrate of the BSAO enzyme. MDR cells are more sensitive to the toxic polyamine metabolites than WT cells, thus indicating a new therapeutic strategy to overcome MDR tumors. Since SMOX in mammals is differentially activated in a tissue-specific manner and cancer cells can differ in terms of DNA repair and MDR capabilities, it could be of interest to simultaneously treat with very low dose of X-rays and/or to alter SMOX metabolism to generate a differential response in healthy and cancer tissues.

Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection.

PubMed

Shen, Jing; Liang, Qingfeng; Su, Guanyu; Zhang, Yang; Wang, Zhiqun; Liang, Hong; Baudouin, Christophe; Labbé, Antoine

2017-01-01

In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm 2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus , Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.

Effect of Ultraviolet Light Irradiation on Structure and Electrochemical Properties of Iron Surface

NASA Astrophysics Data System (ADS)

Nanjo, Hiroshi; Deng, Huihua; Oconer, Irmin S.; Ishikawa, Ikuo; Suzuki, Toshishige M.

2005-01-01

The effect of ultraviolet light (UV) irradiation (254 nm, 0.8 mW/cm2) on air-formed oxide films and passivated films on iron was investigated by electrochemical methods and scanning tunneling microscopy (STM), in particular with respect to surface micro/nanostructures and the surface protective property. An as-deposited film appeared uniformly flat after UV irradiation for 2-4 h, which is associated with a decrease in current density. UV irradiation for 1-4 h assisted N-dodecylhydroxamic acid (DHA) molecules to strongly bond to the air-formed oxide film. UV irradiation for 1 h led to the formation of a flat terrace of atomic resolution on a surface passivated at 800 mV for 15 min. However, it was difficult to observe a terrace wider than 3 nm on the passive film irradiated for 4 h.

UV-induced effects on chlorination of creatinine.

PubMed

Weng, Shih Chi; Li, Jing; Wood, Karl V; Kenttämaa, Hilkka I; Williams, Peggy E; Amundson, Lucas M; Blatchley, Ernest R

2013-09-15

Ultraviolet (UV) irradiation is commonly employed for water treatment in swimming pools to complement conventional chlorination, and to reduce the concentration of inorganic chloramine compounds. The approach of combining UV irradiation and chlorination has the potential to improve water quality, as defined by microbial composition. However, relatively little is known about the effects of this process on water chemistry. To address this issue, experiments were conducted to examine the effects of sequential UV254 irradiation/chlorination, as will occur in recirculating system of swimming pools, on disinfection byproduct (DBP) formation. Creatinine, which is present in human sweat and urine, was selected as the target precursor for these experiments. Enhanced formation of dichloromethylamine (CH3NCl2) and inorganic chloramines was observed to result from post-chlorination of UV-irradiated samples. Chlorocreatinine was found to be more sensitive to UV254 irradiation than creatinine; UV254 irradiation of chlorocreatinine resulted in opening of the ring structure, thereby yielding a series of intermediates that were more susceptible to free chlorine attack than their parent compound. The quantum yields for photodegradation of creatinine and chlorocreatinine at 254 nm were estimated at 0.011 ± 0.002 mol/E and 0.144 ± 0.011 mol/E, respectively. The N-Cl bond was found to be common to UV-sensitive chlorinated compounds (e.g., inorganic chloramines, CH3NCl2, and chlorocreatinine); compounds that were less susceptible to UV-based attack generally lacked the N-Cl bond. This suggested that the N-Cl bond is susceptible to UV254 irradiation, and cleavage of the N-Cl bond appears to open or promote reaction pathways that involve free chlorine, thereby enhancing formation of some DBPs and promoting loss of free chlorine. Proposed reaction mechanisms to describe this behavior based on creatinine as a precursor are presented. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potential of the homeopathic remedy, Arnica Montana 30C, to reduce DNA damage in Escherichia coli exposed to ultraviolet irradiation through up-regulation of nucleotide excision repair genes.

PubMed

Das, Sreemanti; Saha, Santu Kumar; De, Arnab; Das, Durba; Khuda-Bukhsh, Anisur Rahman

2012-03-01

To examine to what degree an ultra-highly diluted homeopathic remedy, Arnica Montana 30C (AM-30C), used in the treatment of shock and injury, can modulate the expression of nucleotide excision repair genes in Escherichia coli exposed to ultraviolet (UV) irradiation. E. coli were cultured to their log phase in a standard Luria-Bertani medium and then exposed to sublethal doses of UV irradiation at 25 and 50 J/m(2) for 22.5 and 45 s, respectively. The UV-exposed bacteria were then supplemented with either AM-30C (drug) or placebo (P-30C). The drug-treated and placebo-treated bacteria were subjected to assay for DNA damage and oxidative stress 90 min after UV exposure. Several protocols like comet assay, gel electrophoresis for DNA ladder and intracellular reactive oxygen species (ROS) generation, and biomarker measurement like superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) were conducted. The mRNA expressions of the excision repair genes like ultraviolet repair uvrA, B and C genes (or also known as excision repair genes) were estimated by reverse transcription-polymerase chain reaction method. The UV-exposed bacteria showed DNA damage and oxidative stress, as revealed by an increase in ROS generation, and a decrease in SOD, CAT and GSH activities. As compared to placebo, the AM-30C-treated bacteria showed less DNA damage and oxidative stress as manifested by a decrease in ROS generation, and an increase in SOD, CAT and GSH activities. AM-30C also up-regulated the expression of repair genes as compared to the control. AM-30C helped repair the DNA damage through up-regulation of repair genes and also ameliorated the oxidative stress through the reduction of ROS generation and suitable modulation of anti-oxidative stress enzymes.

Application of UV-irradiated Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton systems to degrade model and natural occurring naphthenic acids.

PubMed

Zhang, Ying; Chelme-Ayala, Pamela; Klamerth, Nikolaus; Gamal El-Din, Mohamed

2017-07-01

Naphthenic acids (NAs) are a highly complex mixture of organic compounds naturally present in bitumen and identified as the primary toxic constituent of oil sands process-affected water (OSPW). This work investigated the degradation of cyclohexanoic acid (CHA), a model NA compound, and natural occurring NAs during the UV photolysis of Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton processes. The results indicated that in the UV-Fe(III)NTA process at pH 8, the CHA removal increased with increasing NTA dose (0.18, 0.36 and 0.72 mM), while it was independent of the Fe(III) dose (0.09, 0.18 and 0.36 mM). Moreover, the three Fe concentrations had no influence on the photolysis of the Fe(III)NTA complex. The main responsible species for the CHA degradation was hydroxyl radical (OH), and the role of dissolved O 2 in the OH generation was found to be negligible. Real OSPW was treated with the UV-Fe(III)NTA and UV-NTA-Fenton advanced oxidation processes (AOPs). The removals of classical NAs (O 2 -NAs), oxidized NAs with one additional oxygen atom (O 3 -NAs) and with two additional oxygen atoms (O 4 -NAs) were 44.5%, 21.3%, and 25.2% in the UV-Fe(III)NTA process, respectively, and 98.4%, 86.0%, and 81.0% in the UV-NTA-Fenton process, respectively. There was no influence of O 2 on the NA removal in these two processes. The results also confirmed the high reactivity of the O 2 -NA species with more carbons and increasing number of rings or double bond equivalents. This work opens a new window for the possible treatment of OSPW at natural pH using these AOPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Feasibility of ultraviolet-light-emitting diodes as an alternative light source for photocatalysis.

PubMed

Levine, Lanfang H; Richards, Jeffrey T; Coutts, Janelle L; Soler, Robert; Maxik, Fred; Wheeler, Raymond M

2011-09-01

The objective of this study was to determine whether ultraviolet-light-emitting diodes (UV-LEDs) could serve as an efficient photon source for heterogeneous photocatalytic oxidation (PCO). An LED module consisting of 12 high-power UV-A (lambda max = 365 nm) LEDs was designed to be interchangeable with a UV-A fluorescent black light blue (BLB) lamp for a bench scale annular reactor packed with silica-titania composite (STC) pellets. Lighting and thermal properties of the module were characterized to assess its uniformity and total irradiance. A forward current (I(F)) of 100 mA delivered an average irradiance of 4.0 mW cm(-2) at a distance of 8 mm, which is equivalent to the maximum output of the BLB, but the irradiance of the LED module was less uniform than that of the BLB. The LED and BLB reactors were tested for the oxidization of ethanol (50 ppm(v)) in a continuous-flow-through mode with 0.94 sec residence time. At the same average irradiance, the UV-A LED reactor resulted in a lower CO2 production rate (19.8 vs. 28.6 nmol L(-1) s(-1)), lower ethanol removal (80% vs. 91%), and lower mineralization efficiency (28% vs. 44%) than the UV-A BLB reactor. Ethanol mineralization was enhanced with the increase of the irradiance at the catalyst surface. This result suggests that reduced ethanol mineralization in the LED reactor relative to the BLB reactor at the same average irradiance could be attributed to the nonuniform irradiance over the photocatalyst, that is, a portion of the catalyst was exposed to less than the average irradiance. The potential of UV-A LEDs may be fully realized by optimizing the light distribution over the catalyst and utilizing their instantaneous "on" and "off" feature for periodic irradiation. Nevertheless, our results also showed that the current UV-A LED module had the same wall plug efficiency (WPE) of 13% as that of the UV-A BLB, demonstrating that UV-A LEDs are a viable photon source both in terms of WPE and PCO efficiency.

Effect of Shadowing on Survival of Bacteria under Conditions Simulating the Martian Atmosphere and UV Radiation▿ †

PubMed Central

Osman, Shariff; Peeters, Zan; La Duc, Myron T.; Mancinelli, Rocco; Ehrenfreund, Pascale; Venkateswaran, Kasthuri

2008-01-01

Spacecraft-associated spores and four non-spore-forming bacterial isolates were prepared in Atacama Desert soil suspensions and tested both in solution and in a desiccated state to elucidate the shadowing effect of soil particulates on bacterial survival under simulated Martian atmospheric and UV irradiation conditions. All non-spore-forming cells that were prepared in nutrient-depleted, 0.2-μm-filtered desert soil (DSE) microcosms and desiccated for 75 days on aluminum died, whereas cells prepared similarly in 60-μm-filtered desert soil (DS) microcosms survived such conditions. Among the bacterial cells tested, Microbacterium schleiferi and Arthrobacter sp. exhibited elevated resistance to 254-nm UV irradiation (low-pressure Hg lamp), and their survival indices were comparable to those of DS- and DSE-associated Bacillus pumilus spores. Desiccated DSE-associated spores survived exposure to full Martian UV irradiation (200 to 400 nm) for 5 min and were only slightly affected by Martian atmospheric conditions in the absence of UV irradiation. Although prolonged UV irradiation (5 min to 12 h) killed substantial portions of the spores in DSE microcosms (∼5- to 6-log reduction with Martian UV irradiation), dramatic survival of spores was apparent in DS-spore microcosms. The survival of soil-associated wild-type spores under Martian conditions could have repercussions for forward contamination of extraterrestrial environments, especially Mars. PMID:18083857

Solar UV Variations During the Decline of Cycle 23

NASA Technical Reports Server (NTRS)

DeLand, Matthew, T.; Cebula, Richard P.

2011-01-01

Characterization of temporal and spectral variations in solar ultraviolet irradiance over a solar cycle is essential for understanding the forcing of Earth's atmosphere and climate. Satellite measurements of solar UV variability for solar cycles 21, 22, and 23 show consistent solar cycle irradiance changes at key wavelengths (e.g. 205 nm, 250 nm) within instrumental uncertainties. All historical data sets also show the same relative spectral dependence for both short-term (rotational) and long-term (solar cycle) variations. Empirical solar irradiance models also produce long-term solar UV variations that agree well with observational data. Recent UV irradiance data from the Solar Radiation and Climate Experiment (SORCE) Spectral Irradiance Monitor (SIM) and Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instruments covering the declining phase of Cycle 23 present a different picture oflong-term solar variations from previous results. Time series of SIM and SOLSTICE spectral irradiance data between 2003 and 2007 show solar variations that greatly exceed both previous measurements and predicted irradiance changes over this period, and the spectral dependence of the SIM and SOLSTICE variations during these years do not show features expected from solar physics theory. The use of SORCE irradiance variations in atmospheric models yields substantially different middle atmosphere ozone responses in both magnitude and vertical structure. However, short-term solar variability derived from SIM and SOLSTICE UV irradiance data is consistent with concurrent solar UV measurements from other instruments, as well as previous results, suggesting no change in solar physics. Our analysis of short-term solar variability is much less sensitive to residual instrument response changes than the observations of long-term variations. The SORCE long-term UV results can be explained by under-correction of instrument response changes during the first few years of measurements, rather than requiring an unexpected change in the physical behavior of the Sun.

UV solar irradiance in observations and the NRLSSI and SATIRE-S models

NASA Astrophysics Data System (ADS)

Yeo, K. L.; Ball, W. T.; Krivova, N. A.; Solanki, S. K.; Unruh, Y. C.; Morrill, J.

2015-08-01

Total solar irradiance and UV spectral solar irradiance has been monitored since 1978 through a succession of space missions. This is accompanied by the development of models aimed at replicating solar irradiance by relating the variability to solar magnetic activity. The Naval Research Laboratory Solar Spectral Irradiance (NRLSSI) and Spectral And Total Irradiance REconstruction for the Satellite era (SATIRE-S) models provide the most comprehensive reconstructions of total and spectral solar irradiance over the period of satellite observation currently available. There is persistent controversy between the various measurements and models in terms of the wavelength dependence of the variation over the solar cycle, with repercussions on our understanding of the influence of UV solar irradiance variability on the stratosphere. We review the measurement and modeling of UV solar irradiance variability over the period of satellite observation. The SATIRE-S reconstruction is consistent with spectral solar irradiance observations where they are reliable. It is also supported by an independent, empirical reconstruction of UV spectral solar irradiance based on Upper Atmosphere Research Satellite/Solar Ultraviolet Spectral Irradiance Monitor measurements from an earlier study. The weaker solar cycle variability produced by NRLSSI between 300 and 400 nm is not evident in any available record. We show that although the method employed to construct NRLSSI is principally sound, reconstructed solar cycle variability is detrimentally affected by the uncertainty in the SSI observations it draws upon in the derivation. Based on our findings, we recommend, when choosing between the two models, the use of SATIRE-S for climate studies.

Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation

PubMed Central

Newcombe, David A.; Schuerger, Andrew C.; Benardini, James N.; Dickinson, Danielle; Tanner, Roger; Venkateswaran, Kasthuri

2005-01-01

Spore-forming microbes recovered from spacecraft surfaces and assembly facilities were exposed to simulated Martian UV irradiation. The effects of UVA (315 to 400 nm), UVA+B (280 to 400 nm), and the full UV spectrum (200 to 400 nm) on the survival of microorganisms were studied at UV intensities expected to strike the surfaces of Mars. Microbial species isolated from the surfaces of several spacecraft, including Mars Odyssey, X-2000 (avionics), and the International Space Station, and their assembly facilities were identified using 16S rRNA gene sequencing. Forty-three Bacillus spore lines were screened, and 19 isolates showed resistance to UVC irradiation (200 to 280 nm) after exposure to 1,000 J m−2 of UVC irradiation at 254 nm using a low-pressure mercury lamp. Spores of Bacillus species isolated from spacecraft-associated surfaces were more resistant than a standard dosimetric strain, Bacillus subtilis 168. In addition, the exposure time required for UVA+B irradiation to reduce the viable spore numbers by 90% was 35-fold longer than the exposure time required for the full UV spectrum to do this, confirming that UVC is the primary biocidal bandwidth. Among the Bacillus species tested, spores of a Bacillus pumilus strain showed the greatest resistance to all three UV bandwidths, as well as the total spectrum. The resistance to simulated Mars UV irradiation was strain specific; B. pumilus SAFR-032 exhibited greater resistance than all other strains tested. The isolation of organisms like B. pumilus SAFR-032 and the greater survival of this organism (sixfold) than of the standard dosimetric strains should be considered when the sanitation capabilities of UV irradiation are determined. PMID:16332797

Survival of spacecraft-associated microorganisms under simulated martian UV irradiation.

PubMed

Newcombe, David A; Schuerger, Andrew C; Benardini, James N; Dickinson, Danielle; Tanner, Roger; Venkateswaran, Kasthuri

2005-12-01

Spore-forming microbes recovered from spacecraft surfaces and assembly facilities were exposed to simulated Martian UV irradiation. The effects of UVA (315 to 400 nm), UVA+B (280 to 400 nm), and the full UV spectrum (200 to 400 nm) on the survival of microorganisms were studied at UV intensities expected to strike the surfaces of Mars. Microbial species isolated from the surfaces of several spacecraft, including Mars Odyssey, X-2000 (avionics), and the International Space Station, and their assembly facilities were identified using 16S rRNA gene sequencing. Forty-three Bacillus spore lines were screened, and 19 isolates showed resistance to UVC irradiation (200 to 280 nm) after exposure to 1,000 J m(-2) of UVC irradiation at 254 nm using a low-pressure mercury lamp. Spores of Bacillus species isolated from spacecraft-associated surfaces were more resistant than a standard dosimetric strain, Bacillus subtilis 168. In addition, the exposure time required for UVA+B irradiation to reduce the viable spore numbers by 90% was 35-fold longer than the exposure time required for the full UV spectrum to do this, confirming that UVC is the primary biocidal bandwidth. Among the Bacillus species tested, spores of a Bacillus pumilus strain showed the greatest resistance to all three UV bandwidths, as well as the total spectrum. The resistance to simulated Mars UV irradiation was strain specific; B. pumilus SAFR-032 exhibited greater resistance than all other strains tested. The isolation of organisms like B. pumilus SAFR-032 and the greater survival of this organism (sixfold) than of the standard dosimetric strains should be considered when the sanitation capabilities of UV irradiation are determined.

Effect of gamma irradiation on the expressed proteins in the foodborne pathogen Staphylococcus aureus

NASA Astrophysics Data System (ADS)

Trudeau, Karine; Dang Vu, Khanh; Shareck, François; Lacroix, Monique

2012-08-01

A capillary electrophoresis method with UV detection was developed to analyze protein composition of the foodborne pathogen Staphylococcus aureus. Bacterial samples containing 109 CFU/ml, obtained after two cycles of incubations of 24 h, were gamma irradiated at different doses of 1.2, 3.5 and 2.9 kGy to respectively create damage cells, to kill cells and to provoke viable but non cultivable cells (VBNC). It was observed that an irradiation at a sensitive dose of 1.2 kGy caused a significantly increase in the protein with molecular weight (MW) of 17.7 kDa (from 0.61% to 1.2%). This treatment also caused decreases in the expressed proteins with the MWs of 16.3 kDa (from 6.2% to 5.3%) and of 23.4 kDa (from 4.0% to 2.30%). Irradiation at a VBCN dose of 2.9 kGy caused increases in expressed proteins with the MWs of 17.7 kDa (from 0.61% to 3.43%), 18.7 kDa (from 1.04% to 4.30%), 19.5 kDa (from 0.71% to 2.30%), 21.1 kDa (from 1.20% to 3.80%). Moreover, this treatment (2.9 kGy) also caused significantly decreases (P≤0.05) in the expressed proteins with the MW of 30.7 kDa (from 8.6% to 5.15%), 36.3 kDa (from 3.1% to 2.7%) and 40.5 kDa (from 11.3% to 8.5%). Finally, for the irradiation at a lethal dose of 3.5 kGy, it can be found that the expressed proteins with the MW of 17.7 kDa, 18.7 kDa and 19.5 kDa were increased less than that of expressed proteins at the VCNC dose (2.9 kGy) and these might be the very important proteins which are responsible for the survival of the S. aureus. Further, there were also the decreases in expressed proteins with the MW of 30.7 kDa, 36.3 kDa and 75.1 kDa at this dose of treatment (3.5 kGy) which can be expected that these proteins are seriously affected at high dose of γ-irradiation treatment.

Replication of adeno-associated virus in cells irradiated with UV light at 254 nm

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

Yakobson, B.; Hrynko, T.A.; Peak, M.J.

1989-03-01

Irradiation of simian virus 40 (ori mutant)-transformed Chinese hamster embryo cells (OD4 line) with UV light induced a cellular capacity which supported a full cycle of helper-independent adeno-associated virus replication. Monochromatic UV light at 254 nm was about 1,000-fold more effective than UV light at 313 nm, indicating that cellular nucleic acid is the primary chromophore in the UV-induced process leading to permissiveness for adeno-associated virus replication. The UV irradiation and the infection could be separated for up to 12 h without substantial loss of permissiveness. During this time interval, the induction process was partly sensitive to cycloheximide, suggesting amore » requirement for de novo protein synthesis.« less

Lethal effect of uv and $gamma$ irradiation on some species of Dematiaceae (in Russian)

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

Zhdanova, N.N.; Gavryushina, A.I.; Bondar, A.I.

1972-01-01

A comparative study was conducted of relation of four species of Dematiaceae and a mutant with lowered content of melanine to gamma and uv rays. Under uv irradiation, survival iate of all studied species was characterized by a complex exponential curve with a large, sharply pronounced resistant area. An assumption is advanced that a sharp fall of survival rate during the first minutes of uv irradiation is conditioned by specificity of the protective effect of melanine pigment tint needs time for transition into the active state. Species resistant to gamma irradiation had sygmoid curves of survival rate and sensitive speciesmore » had the exponential ones. Increased resistance to gamma rays was accompanied by an increase in concentration of paramagnetic-particles that were determined by the method of electronic paramagnetic resonance. Analysis of the data obtained makes it possible to suppose that the protective effect of fungal melanine is various under gamma and uv irradiation. (auth)« less

UV-B inhibition of hypocotyl growth in etiolated Arabidopsis thaliana seedlings is a consequence of cell cycle arrest initiated by photodimer accumulation

PubMed Central

Biever, Jessica J.; Brinkman, Doug; Gardner, Gary

2014-01-01

Ultraviolet (UV) radiation is an important constituent of sunlight that determines plant morphology and growth. It induces photomorphogenic responses but also causes damage to DNA. Arabidopsis mutants of the endonucleases that function in nucleotide excision repair, xpf-3 and uvr1-1, showed hypersensitivity to UV-B (280–320nm) in terms of inhibition of hypocotyl growth. SOG1 is a transcription factor that functions in the DNA damage signalling response after γ-irradiation. xpf mutants that carry the sog1-1 mutation showed hypocotyl growth inhibition after UV-B irradiation similar to the wild type. A DNA replication inhibitor, hydroxyurea (HU), also inhibited hypocotyl growth in etiolated seedlings, but xpf-3 was not hypersensitive to HU. UV-B irradiation induced accumulation of the G2/M-specific cell cycle reporter construct CYCB1;1-GUS in wild-type Arabidopsis seedlings that was consistent with the expected accumulation of photodimers and coincided with the time course of hypocotyl growth inhibition after UV-B treatment. Etiolated mutants of UVR8, a recently described UV-B photoreceptor gene, irradiated with UV-B showed inhibition of hypocotyl growth that was not different from that of the wild type, but they lacked UV-B-specific expression of chalcone synthase (CHS), as expected from previous reports. CHS expression after UV-B irradiation was not different in xpf-3 compared with the wild type, nor was it altered after HU treatment. These results suggest that hypocotyl growth inhibition by UV-B light in etiolated Arabidopsis seedlings, a photomorphogenic response, is dictated by signals originating from UV-B absorption by DNA that lead to cell cycle arrest. This process occurs distinct from UVR8 and its signalling pathway responsible for CHS induction. PMID:24591052

Effect of UV irradiation on the dynamics of oxygen and water interaction with carbon nanotubes

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

Nelson, Anthony J; Ivanov, Ilia N

2016-01-01

Carbon nanotube (CNT) films composed of semiconducting single wall nanotubes (s-SWNTs), metallic single wall nanotubes (m-SWNTs), and multiwall nanotubes (MWNTs) were exposed to O2 and H2O vapor in the dark and under UV irradiation. Changes in the film conductivity and mass were measured in situ. We find that UV irradiation increases the resistive response of CNT films to O2 and H2O by more than an order of magnitude. In m-SWNT and MWNT films, UV irradiation changes the sign of the resistive response to O2 and H2O by generating free charge carriers. S-SWNTs show the largest UV-induced resistive response and exhibitmore » weakening of van der Waals interactions with the QCM crystal when exposed to gas/vapor.« less

Impact of Dissolved Oxygen during UV-Irradiation on the Chemical Composition and Function of CHO Cell Culture Media.

PubMed

Meunier, Sarah M; Todorovic, Biljana; Dare, Emma V; Begum, Afroza; Guillemette, Simon; Wenger, Andrew; Saxena, Priyanka; Campbell, J Larry; Sasges, Michael; Aucoin, Marc G

2016-01-01

Ultraviolet (UV) irradiation is advantageous as a sterilization technique in the biopharmaceutical industry since it is capable of targeting non-enveloped viruses that are typically challenging to destroy, as well as smaller viruses that can be difficult to remove via conventional separation techniques. In this work, we investigated the influence of oxygen in the media during UV irradiation and characterized the effect on chemical composition using NMR and LC-MS, as well as the ability of the irradiated media to support cell culture. Chemically defined Chinese hamster ovary cell growth media was irradiated at high fluences in a continuous-flow UV reactor. UV-irradiation caused the depletion of pyridoxamine, pyridoxine, pyruvate, riboflavin, tryptophan, and tyrosine; and accumulation of acetate, formate, kynurenine, lumichrome, and sarcosine. Pyridoxamine was the only compound to undergo complete degradation within the fluences considered; complete depletion of pyridoxamine was observed at 200 mJ/cm2. Although in both oxygen- and nitrogen-saturated media, the cell culture performance was affected at fluences above 200 mJ/cm2, there was less of an impact on cell culture performance in the nitrogen-saturated media. Based on these results, minimization of oxygen in cell culture media prior to UV treatment is recommended to minimize the negative impact on sensitive media.

Impact of Dissolved Oxygen during UV-Irradiation on the Chemical Composition and Function of CHO Cell Culture Media

PubMed Central

Meunier, Sarah M.; Todorovic, Biljana; Dare, Emma V.; Begum, Afroza; Guillemette, Simon; Wenger, Andrew; Saxena, Priyanka; Campbell, J. Larry; Sasges, Michael; Aucoin, Marc G.

2016-01-01

Ultraviolet (UV) irradiation is advantageous as a sterilization technique in the biopharmaceutical industry since it is capable of targeting non-enveloped viruses that are typically challenging to destroy, as well as smaller viruses that can be difficult to remove via conventional separation techniques. In this work, we investigated the influence of oxygen in the media during UV irradiation and characterized the effect on chemical composition using NMR and LC-MS, as well as the ability of the irradiated media to support cell culture. Chemically defined Chinese hamster ovary cell growth media was irradiated at high fluences in a continuous-flow UV reactor. UV-irradiation caused the depletion of pyridoxamine, pyridoxine, pyruvate, riboflavin, tryptophan, and tyrosine; and accumulation of acetate, formate, kynurenine, lumichrome, and sarcosine. Pyridoxamine was the only compound to undergo complete degradation within the fluences considered; complete depletion of pyridoxamine was observed at 200 mJ/cm2. Although in both oxygen- and nitrogen-saturated media, the cell culture performance was affected at fluences above 200 mJ/cm2, there was less of an impact on cell culture performance in the nitrogen-saturated media. Based on these results, minimization of oxygen in cell culture media prior to UV treatment is recommended to minimize the negative impact on sensitive media. PMID:26975046

Fast simulation tool for ultraviolet radiation at the earth's surface

NASA Astrophysics Data System (ADS)

Engelsen, Ola; Kylling, Arve

2005-04-01

FastRT is a fast, yet accurate, UV simulation tool that computes downward surface UV doses, UV indices, and irradiances in the spectral range 290 to 400 nm with a resolution as small as 0.05 nm. It computes a full UV spectrum within a few milliseconds on a standard PC, and enables the user to convolve the spectrum with user-defined and built-in spectral response functions including the International Commission on Illumination (CIE) erythemal response function used for UV index calculations. The program accounts for the main radiative input parameters, i.e., instrumental characteristics, solar zenith angle, ozone column, aerosol loading, clouds, surface albedo, and surface altitude. FastRT is based on look-up tables of carefully selected entries of atmospheric transmittances and spherical albedos, and exploits the smoothness of these quantities with respect to atmospheric, surface, geometrical, and spectral parameters. An interactive site, http://nadir.nilu.no/~olaeng/fastrt/fastrt.html, enables the public to run the FastRT program with most input options. This page also contains updated information about FastRT and links to freely downloadable source codes and binaries.

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

PubMed

Hölzle, Erhard; Hönigsmann, Herbert

2005-09-01

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

Dual UV irradiation-based metal oxide nanoparticles for enhanced antimicrobial activity in Escherichia coli and M13 bacteriophage

PubMed Central

Jin, Su-Eon; Hwang, Woochul; Lee, Hyo Jung; Jin, Hyo-Eon

2017-01-01

Metal oxide (MO) nanoparticles have been studied as nano-antibiotics due to their antimicrobial activities even in antibiotic-resistant microorganisms. We hypothesized that a hybrid system of dual UV irradiation and MO nanoparticles would have enhanced antimicrobial activities compared with UV or MO nanoparticles alone. In this study, nanoparticles of ZnO, ZnTiO3, MgO, and CuO were selected as model nanoparticles. A dual UV collimated beam device of UV-A and UV-C was developed depending upon the lamp divided by coating. Physicochemical properties of MO nanoparticles were determined using powder X-ray diffractometry (PXRD), Brunauer-Emmett-Teller analysis, and field emission-scanning electron microscopy with energy-dispersive X-ray spectroscopy. Atomic force microscopy with an electrostatic force microscopy mode was used to confirm the surface topology and electrostatic characteristics after dual UV irradiation. For antimicrobial activity test, MO nanoparticles under dual UV irradiation were applied to Escherichia coli and M13 bacteriophage (phage). The UV-A and UV-C showed differential intensities in the coated and uncoated areas (UV-A, coated = uncoated; UV-C, coated ≪ uncoated). MO nanoparticles showed sharp peaks in PXRD patterns, matched to pure materials. Their primary particle sizes were less than 100 nm with irregular shapes, which had an 8.6~25.6 m2/g of specific surface area with mesopores of 22~262 nm. The electrostatic properties of MO nanoparticles were modulated after UV irradiation. ZnO, MgO, and CuO nanoparticles, except ZnTiO3 nanoparticles, showed antibacterial effects on E. coli. Antimicrobial effects on E. coli and phages were also enhanced after cyclic exposure of dual UV and MO nanoparticle treatment using the uncoated area, except ZnO nanoparticles. Our results demonstrate that dual UV-MO nanoparticle hybrid system has a potential for disinfection. We anticipate that it can be developed as a next-generation disinfection system in pharmaceutical industries and water purification systems. PMID:29138562

Dual UV irradiation-based metal oxide nanoparticles for enhanced antimicrobial activity in Escherichia coli and M13 bacteriophage.

PubMed

Jin, Su-Eon; Hwang, Woochul; Lee, Hyo Jung; Jin, Hyo-Eon

2017-01-01

Metal oxide (MO) nanoparticles have been studied as nano-antibiotics due to their antimicrobial activities even in antibiotic-resistant microorganisms. We hypothesized that a hybrid system of dual UV irradiation and MO nanoparticles would have enhanced antimicrobial activities compared with UV or MO nanoparticles alone. In this study, nanoparticles of ZnO, ZnTiO 3 , MgO, and CuO were selected as model nanoparticles. A dual UV collimated beam device of UV-A and UV-C was developed depending upon the lamp divided by coating. Physicochemical properties of MO nanoparticles were determined using powder X-ray diffractometry (PXRD), Brunauer-Emmett-Teller analysis, and field emission-scanning electron microscopy with energy-dispersive X-ray spectroscopy. Atomic force microscopy with an electrostatic force microscopy mode was used to confirm the surface topology and electrostatic characteristics after dual UV irradiation. For antimicrobial activity test, MO nanoparticles under dual UV irradiation were applied to Escherichia coli and M13 bacteriophage (phage). The UV-A and UV-C showed differential intensities in the coated and uncoated areas (UV-A, coated = uncoated; UV-C, coated ≪ uncoated). MO nanoparticles showed sharp peaks in PXRD patterns, matched to pure materials. Their primary particle sizes were less than 100 nm with irregular shapes, which had an 8.6~25.6 m 2 /g of specific surface area with mesopores of 22~262 nm. The electrostatic properties of MO nanoparticles were modulated after UV irradiation. ZnO, MgO, and CuO nanoparticles, except ZnTiO 3 nanoparticles, showed antibacterial effects on E. coli . Antimicrobial effects on E. coli and phages were also enhanced after cyclic exposure of dual UV and MO nanoparticle treatment using the uncoated area, except ZnO nanoparticles. Our results demonstrate that dual UV-MO nanoparticle hybrid system has a potential for disinfection. We anticipate that it can be developed as a next-generation disinfection system in pharmaceutical industries and water purification systems.

Spectral irradiance measurement and actinic radiometer calibration for UV water disinfection

NASA Astrophysics Data System (ADS)

Sperfeld, Peter; Barton, Bettina; Pape, Sven; Towara, Anna-Lena; Eggers, Jutta; Hopfenmüller, Gabriel

2014-12-01

In a joint project, sglux and PTB investigated and developed methods and equipment to measure the spectral and weighted irradiance of high-efficiency UV-C emitters used in water disinfection plants. A calibration facility was set up to calibrate the microbicidal irradiance responsivity of actinic radiometers with respect to the weighted spectral irradiance of specially selected low-pressure mercury and medium-pressure mercury UV lamps. To verify the calibration method and to perform on-site tests, spectral measurements were carried out directly at water disinfection plants in operation. The weighted microbicidal irradiance of the plants was calculated and compared to the measurements of various actinic radiometers.

Ultraviolet irradiation and gradient temperature assisted autolysis for protein recovery from shrimp head waste.

PubMed

Cao, Wenhong; Tan, Caiyun; Zhan, Xiaojian; Li, Huiyi; Zhang, Chaohua

2014-12-01

A novel autolysis method using ultraviolet (UV) irradiation and gradient temperature was investigated to efficiently recover proteins from the head of the shrimp Penaeus vannamei. The proteolytic activity of shrimp head subjected to 30W UV irradiation for 20 min was increased by 62%, compared with that of untreated samples. After irradiation, the enzymes remained active across a wide range of temperatures (45-60°C) and pH (7-10). An orthogonal design was used to optimize autolysis condition. After 5h autolysis, protein recovery from the UV-heat treated samples was up to 92.1%. These results indicate the potential of using UV irradiation in combination with gradient temperatures to improve recovery of proteins from shrimp head waste. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Objective Assessment of Sunburn and Minimal Erythema Doses: Comparison of Noninvasive In Vivo Measuring Techniques after UVB Irradiation

NASA Astrophysics Data System (ADS)

Huang, Min-Wei; Lo, Pei-Yu; Cheng, Kuo-Sheng

2010-12-01

Military personnel movement is exposed to solar radiation and sunburn is a major problem which can cause lost workdays and lead to disciplinary action. This study was designed to identify correlation parameters in evaluating in vivo doses and epidermis changes following sunburn inflammation. Several noninvasive bioengineering techniques have made objective evaluations possible. The volar forearms of healthy volunteers ([InlineEquation not available: see fulltext.]), 2 areas, 20 mm in diameter, were irradiated with UVB 100 mj/[InlineEquation not available: see fulltext.] and 200 mj/[InlineEquation not available: see fulltext.], respectively. The skin changes were recorded by several monitored techniques before and 24 hours after UV exposures. Our results showed that chromameter [InlineEquation not available: see fulltext.] value provides more reliable information and can be adopted with mathematical model in predicting the minimal erythema dose (MED) which showed lower than visual assessment by 10 mj/[InlineEquation not available: see fulltext.] (Pearson correlation coefficient [InlineEquation not available: see fulltext.]). A more objective measure for evaluation of MED was established for photosensitive subjects' prediction and sunburn risks prevention.

Synergistic effects of TiO2 and Cu2O in UV/TiO2/zeolite-based systems on photodegradation of bisphenol A.

PubMed

Kuo, Chao-Yin; Wu, Chung-Hsin; Lin, Han-Yu

2014-08-01

In this study, TiO2/zeolite (TZ)-based composite was utilized to degrade bisphenol A (BPA) under ultraviolet (UV) irradiation. The effects of the TiO2 and Cu2O doses in TZ and Cu2O/TiO2/zeolite (CTZ) on the rate of BPA removal were identified, respectively. The surface area of TZ declined as the TiO2 loading increased. The photodegradation rate (k) of BPA in the TZ and CTZ systems fitted pseudo-first-order kinetics. Under UV (365 nm) irradiation, the k values of TiO2 (20%)/zeolite (80%), TiO2 (40%)/zeolite (60%), TiO2 (60%)/zeolite (40%), and TiO2 (80%)/zeolite (20%) were 0.51, 0.55, 0.97, and 0.91 h-1, respectively. In the UV (365nm)/TiO2 (60%)/zeolite (40%) system, the k values of CTZ with 1%, 5%, 10%, 20%, and 30% Cu2O added were 1.50, 1.04, 1.15, 1.88, and 0.47h-1, respectively. The photocatalytic activity of TZ was enhanced by adding Cu2O. The optimal dosage of TiO2 in the TZ system was 60% and that of Cu20 in the CTZ system was 20%. p-Hydroxybenzaldehyde (p-HBA), p-hydroxyacetophenone (p-HAP), p-hydroxybenzoic acid (p-HBA acid) and hydroquinone (HQ) were intermediates ofBPA photodegradation in the UV/TZ system and the rates of degradation followed the order HQ > p - HBA acid > BPA > p - HAP > p - HBA.

N-acetylcysteine protects melanocytes against oxidative stress/damage and delays onset of UV-induced melanoma in mice

PubMed Central

Cotter, Murray A.; Thomas, Joshua; Cassidy, Pamela; Robinette, Kyle; Jenkins, Noah; Scott, R. Florell; Leachman, Sancy; Samlowski, Wolfram E.; Grossman, Douglas

2008-01-01

UV radiation is the major environmental risk factor for melanoma and a potent inducer of oxidative stress, which is implicated in the pathogenesis of several malignancies. We evaluated whether the thiol antioxidant N-acetylcysteine (NAC) could protect melanocytes from UV-induced oxidative stress/damage in vitro and from UV-induced melanoma in vivo. In melan-a cells, a mouse melanocyte line, NAC (1–10 mM) conferred protection from several UV-induced oxidative sequelae including production of intracellular peroxide, formation of the signature oxidative DNA lesion 8-oxoguanine (8-OG), and depletion of free reduced thiols (primarily glutathione). Mice transgenic for hepatocyte growth factor and Survivin, previously shown to develop melanoma following a single neonatal dose of UV irradiation, were administered NAC (7 mg/ml, mother’s drinking water) transplacentally and through nursing until two weeks after birth. Delivery of NAC in this manner reduced thiol depletion and blocked formation of 8-OG in skin following neonatal UV treatment. Mean onset of UV-induced melanocytic tumors was significantly delayed in NAC-treated compared to control mice (21 vs. 14 weeks, p=0.0003). Our data highlight the potential importance of oxidative stress in the pathogenesis of melanoma, and suggest that NAC may be useful as a chemopreventive agent. PMID:17908992

Adipochemokines induced by ultraviolet irradiation contribute to impaired fat metabolism in subcutaneous fat cells.

PubMed

Kim, E J; Kim, Y K; Kim, S; Kim, J E; Tian, Y D; Doh, E J; Lee, D H; Chung, J H

2018-02-01

Adipose tissue is now appreciated as the pivotal regulator of metabolic and endocrine functions. Subcutaneous (SC) fat, in contrast to visceral fat, may protect against metabolic syndrome and systemic inflammation. We demonstrated that chronic as well as acute ultraviolet (UV) irradiation to the skin induces loss of underlying SC fat. UV-irradiated SC fat may produce chemokines or cytokines that modulate lipid homeostasis and secretion of adipokines. To elucidate UV-induced specific adipochemokines implicated in UV-induced modulation of SC fat. Primary cultured adipocytes were treated with conditioned medium from UV- or sham-irradiated skin cells. Young and older healthy participants provided SC fat from sun-exposed and sun-protected skin. Sun-protected skin from other participants was irradiated with UV. Differentially expressed adipochemokines were screened by cytokine array, and confirmed in vitro and in vivo. The functions of select adipochemokines involved in lipid metabolism were examined via short interfering RNA-mediated knockdown of cognate receptors. Specific adipochemokines, including C-X-C motif chemokine (CXCL) family members such as CXCL5/ENA-78, and C-C motif chemokine (CCL) family members such as CCL20/MIP-3α and CCL5/RANTES, were greatly induced in SC fat by UV exposure. They could impair triglyceride synthesis via downregulation of lipogenic enzymes and sterol regulatory element-binding protein-1 through their respective cognate receptors, CXC chemokine receptor type (CXC-R)2, C-C chemokine receptor type (CCR)-6, and CCR-5. In addition, UV irradiation induced infiltration of adipose tissue macrophages responsible for the secretion of several chemokines into SC fat. These UV-induced adipochemokines may be implicated in the reduction of lipogenesis in SC fat, leading to impairment of fat homeostasis and associated comorbidities such as obesity. © 2017 British Association of Dermatologists.

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

PubMed Central

Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

2017-01-01

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

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

PubMed

Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

2017-03-09

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

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

NASA Astrophysics Data System (ADS)

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

2013-05-01

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

Protective effect of skin-derived precursors on photoaging in nude mice.

PubMed

Wang, Siyu; Zhong, Jianqiao; Li, Li

2018-06-25

Currently, innovative methods to prevent photoaging are needed. Skin-derived precursors (SKP) have been shown to play a crucial role in resisting UVB-induced apoptosis in vitro. The objective of this study was to explore the effect of SKP on preventing skin photoaging in vivo. Skin-derived precursors from neonatal BALB/c mice were isolated, identified and intradermally transplanted with a PKH26 label to track their survival. These were then injected at different concentrations into the buttock dermis of nude mice at 2-weekly intervals before UV irradiation. Photographs, assessment of live skin surface, histology with quantitative real-time polymerase chain reaction and immunohistochemistry were used to evaluate the impact of SKP on wrinkles and other relevant indicators of skin photoaging. SKP exhibited a sphere-like structure and could survive for at least 2 weeks after intradermal transplantation. A large dose of SKP transplantation (10 5 SKP +UV) at 2-weekly intervals were able to ameliorate coarse UV-induced wrinkles. Moreover, the skin smoothness value, dermal thickness and collagen percentage were significantly increased in mice that received a large dose of SKP (10 5 SKP +UV). UV radiation induced the mRNA expression of MMP-13 and decreased the mRNA and protein expression of TβRII, but these effects were diminished by SKP transplantation. The transplantation of SKP could increase the mRNA of TIMP-1. We found that transplanted SKP exert a beneficial impact on preventing UV-induced wrinkles in vivo, suggesting that SKP transplantation is a promising candidate for preventing photoaging. © 2018 The Australasian College of Dermatologists.

[The 308 nm Excimer laser for the treatment of psoriasis and inflammatory skin diseases].

PubMed

Fritz, K; Salavastru, C

2018-01-01

Overall, the 308 nm Excimer laser enables not only a more effective and safer UVB therapy than classical UV phototherapy, but also targeted irradiation in higher doses with a lower cumulative load, which results in faster healing of mainly circumscribed skin changes. This also applies to therapy-resistant residual lesions which, despite systemic therapy, did not diminish. Combination therapies usually improve the result and enable the dose of UVB and systemic medication to be reduced. Excimer laser therapy can be used for an increasing number of skin diseases, especially those that respond to phototherapy or photochemotherapy.

Studies on the mechanism of printing film-coated tablets containing titanium dioxide in the film by using UV laser irradiation.

PubMed

Kato, Yoshiteru; Nakashima, Yasuhiko; Shino, Naoki; Sasaki, Koichi; Hosokawa, Akihiro; Ishihara, Hiroshi

2010-04-01

The purpose of this article is to study a detailed mechanism of printing when film-coated tablets were irradiated by UV laser at a wavelength of 355 nm. Hydroxypropylmethylcellulose (HPMC) film containing titanium dioxide (TiO(2)) and the film not containing TiO(2) and TiO(2) powder were lirradiated by the UV laser and estimated by the morphological observation by zoom stereo microscope, thermogravimetric analysis (TGA), total color difference (dE), X-ray powder diffraction (XRD), and dispersive Raman microscopy. In the case of the film containing TiO(2), the film showed a visible change in its color from white to gray by the UV laser irradiation. By zoom stereo microscope, it was found that the entire UV laser-irradiated area was not grayed uniformly, but many black particles, whose diameter was about 2 microm, were observed on the film. When TiO(2) powder was irradiated by the UV laser, a visible change in its color from white to gray was observed similar to the case of the film containing TiO(2). There were many black particles locally in the UV laser-treated TiO(2) powder by the morphological observation, and these black particles, agglomerates of the grayed oxygen-defected TiO(2), were associated with the visible change of the TiO(2). It was found that the film-coated tablets were printed utilizing the formation of the black particles by the agglomeration of the grayed oxygen-defected TiO(2) by the UV laser irradiation.

Activation of Peroxisome Proliferator-Activated Receptor Alpha Improves Aged and UV-Irradiated Skin by Catalase Induction.

PubMed

Shin, Mi Hee; Lee, Se-Rah; Kim, Min-Kyoung; Shin, Chang-Yup; Lee, Dong Hun; Chung, Jin Ho

2016-01-01

Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear hormone receptor involved in the transcriptional regulation of lipid metabolism, fatty acid oxidation, and glucose homeostasis. Its activation stimulates antioxidant enzymes such as catalase, whose expression is decreased in aged human skin. Here we investigated the expression of PPARα in aged and ultraviolet (UV)-irradiated skin, and whether PPARα activation can modulate expressions of matrix metalloproteinase (MMP)-1 and procollagen through catalase regulation. We found that PPARα mRNA level was significantly decreased in intrinsically aged and photoaged human skin as well as in UV-irradiated skin. A PPARα activator, Wy14643, inhibited UV-induced increase of MMP-1 and decrease of procollagen expression and caused marked increase in catalase expression. Furthermore, production of reactive oxygen species (ROS) was suppressed by Wy14643 in UV-irradiated and aged dermal fibroblasts, suggesting that the PPARα activation-induced upregulation of catalase leads to scavenging of ROS produced due to UV irradiation or aging. PPARα knockdown decreased catalase expression and abolished the beneficial effects of Wy14643. Topical application of Wy14643 on hairless mice restored catalase activity and prevented MMP-13 and inflammatory responses in skin. Our findings indicate that PPARα activation triggers catalase expression and ROS scavenging, thereby protecting skin from UV-induced damage and intrinsic aging.

The Austrian UVB monitoring network: 12 years of observations and 25 years of reconstructed data

NASA Astrophysics Data System (ADS)

Rieder, H. E.; Weihs, P.; Blumthaler, M.; Simic, S.; Schmalwieser, A. W.; Wagner, J. E.; Schallhart, B.; Schauberger, G.; Fitzka, M.; Holawe, F.; Laube, W.

2009-04-01

Since the discovery of anthropogenic ozone depletion in the early 1970s (e.g. Molina and Rowland, 1974; Farman et al., 1985) the interest in stratospheric ozone trends and solar UV-B increased within the scientific community and the general public because of the link between reduced total column ozone and increased UV-radiation doses. In 1996, the setup of an Austrian UVB monitoring network was initiated by the Federal Department of Environment (Blumthaler and Schauberger, 2001). Now it consists of 12 broadband detectors for measuring erythemally weighted solar UV irradiance at locations between 153 m and 3106 m above sea level. The locations of the stations were selected by objective criteria as spatial coverage and cover the whole altitude range of Austria. With that inter-stational correlation is close to 0.9 (Schmalwieser and Schauberger, 2001). All detectors are calibrated each year in the laboratory of the Division for Biomedical Physics, Innsbruck Medical University. First the relative spectral response of each detector is determined. Then by comparison with a double monochromator spectroradiometer the absolute calibration function is derived in dependence on solar zenith angle and on total atmospheric ozone (Blumthaler, 2004). The uncertainty of the calibration is about ±7% (at 95% confidence level) for solar zenith angles <75°, which is dominated by the uncertainty of the calibration lamp for the spectroradiometer (±4%). During routine operation, the measurements of all detectors are transmitted in near real time to the laboratory and then converted to UV-Indices, the internationally agreed unit for erythemally weighted solar irradiance. The results are then published on the internet (www.uv-index.at) every 15 minutes, together with a regional map showing the distribution of the UV-Index over Austria by combining the information from the measurement detectors with cloud information from Meteosat Second Generation. Recently reconstructed UV-data became available for two stations from the Austrian UVB monitoring network (Hoher Sonnblick and Vienna) (Rieder et al., 2008). An overview about the UVB monitoring network as well as studies on short and long-term trends and the influence of total ozone, surface albedo and cloudiness on erythemal UV (Weihs et al., 1999; Rieder et al., 2008; Simic et al., 2008) are presented. Results from a recent field campaign (Weihs et al., 2008) showed that maintenance of ground based measurements is very important as satellites so far do not satisfactorily represent ground UV. References: Blumthaler, M., and Ambach, W.: Solar UVB-albedo of various surfaces, Photochem. Photobiol., 48, 85-88, 1988. Blumthaler, M.: Quality assurance and quality control methodologies within the Austrian UV monitoring network, Rad. Prot. Dos., 111, 359-362, 2004. Farman, J. C., Gardiner, B. G., and Shanklin, J. D.: Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interaction, Nature, 315, 207-210, 1985. Molina, M. J., and Rowland, F. S.: Stratospheric sink for chlorofluoromethans: Chlorine atom-catalysed destruction of ozone, Nature, 249, 810-812, 1974. Rieder, H.E., Holawe, F., Simic, S., Blumthaler, M., Krzyscin, J.W., Wagner J.E., Schmalwieser A.W., and Weihs, P.: Reconstruction of erythemal UV-doses for two stations in Austria: A comparison between alpine and urban regions, Atmos. Chem. Phys., 8, 6309-6323, 2008. Simic, S., Weihs, P., Vacek, A., Kromp-Kolb, H., and Fitzka, M.: Spectral UV measurements in Austria from 1994 to 2006: investigations of short- and long-term changes, Atmos. Chem. Phys. Discuss., 8, 2403-2428, 2008. Schmalwieser, A.W., and Schauberger, G.: A monitoring network for erythemally-effective solar ultraviolet radiation in Austria: determination of the measuring sites and visualisation of the spatial distribution, Theor. Appl. Climatol., 69, 221-229, 2001. Weihs, P., Simic, S., Laube, W., Mikielewicz, W., Rengarajan, G., Mandl, G.: Albedo influences on surface UV irradiance at the Sonnblick high mountain Observatory (3106 m altitude), J. Appl. Meteorol., 38, 1599-1610, 1999. Weihs, P., Blumthaler, M., Rieder, H. E., Kreuter, A., Simic, S., Laube, W., Schmalwieser, A. W., Wagner, J. E., and Tanskanen, A.: Measurements of UV irradiance within the area of one satellite pixel, Atmos. Chem. Phys., 8, 5615-5626, 2008.

Long-Term Comparisons of OMI Surface UV Irradiances to a NILU_UV Multi-Filter Radiometer in Thessaloniki, Greece

NASA Astrophysics Data System (ADS)

Zempila, Melina Maria; Koukouli, Maria Elissavet; Bais, Alkiviadis; Arola, Antii; Fountoulakis, Ilias; Kouremeti, Natalia; Kazadzis, Stelios; Balis, Dimitrios

2016-08-01

The evaluation of the surface UV irradiances, derived from the Ozone Monitoring Instrument (OMI) onboard the AURA satellite, with those extracted from a Norwegian Institute for Air Research UV multi-filter actinometer (NILU-UV) situated in the Laboratory of Atmospheric Physics (LAP) in the Aristotle University of Thessaloniki (40.69°N, 22.96°E) is presented in this study.The NILU-UV data have been compared with the OMI/Aura overpass and local noon irradiances at 305, 310, 324 and 380 nm for a 10 year period over Thessaloniki between 2005 and 2014.The OMI irradiances were found to overestimate the NILU-UV observations in Thessaloniki between 4.5% and 13.5% for the 305nm wavelength and between 1.5% and 10.0% for the 310nm case. For the 324nm and 380nm, the satellite-deduced local-noon time comparisons showed a satellite under-estimation of 3.75% and 4.15% respectively whereas the overpass-time comparisons range between -1.55% and -1.90% for the same wavelengths.

Color tuning of photonic gel films by UV irradiation

NASA Astrophysics Data System (ADS)

Shin, Sung Eui; Kim, Su Young; Shin, Dong Myung

2010-02-01

Block copolymers have drawn increasing attention for fabricating functional nanomaterials due to their properties of self-assembly. In particular, photonic crystals hold promise for multiple optical applications. We prepared 1D photonic crystals with polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) lamellar films which is hydrophobic block-hydrophilic polyelectrolyte block polymer of 57 kg /mol-b-57 kg/mol. The lamellar stacks, which are alternating layers of hydrophilic and hydrophobic moiety of PS-b-P2VP, are obtained by exposing the spin coated film under chloroform vapor. The band gaps of the lamellar films interestingly varied after immersion into the quaternizing solvents containing 5wt% of iodomethane solubilized in n-hexane. We demonstrate about the influence of UV light on those photonic gel films. To study of different properties of films, UV-visible absorption spectra were measured as a different UV irradiation time at swollen films with distilled water. The UV-visible maximum absorption spectra shifted by UV irradiation time. Dependent on the time of UV irradiations, we can change the photonic band gap.

Protective effect of chromene isolated from Sargassum horneri against UV-A-induced damage in skin dermal fibroblasts.

PubMed

Kim, Jung-Ae; Ahn, Byul-Nim; Kong, Chang-Suk; Kim, Se-Kwon

2012-08-01

Skin homoeostasis is interrupted during UV-A irradiation. How the UV-A-altered skin components influences photoageing of skin should be investigated using human in vitro models that are important for understanding skin ageing. In this study, chromene compound, sargachromenol, was isolated from Sargassum horneri, and its potency on inhibition of photoageing was investigated in UV-A-irradiated dermal fibroblasts. Effects of sargachromenol on the prevention of photoageing were evaluated by measuring ROS production, membrane protein oxidation, lipid peroxidation and ageing-related gene expression in UV-A-irradiated human skin dermal fibroblasts. The results indicated that treatment with sargachromenol suppressed the collagenase matrix metalloproteinases (MMPs), MMP-1, MMP-2 and MMP-9 expression without any cytotoxicity and phototoxicity. It was further found that these inhibitions were because of increase in the expression of TIMP-1 and TIMP-2 genes. Furthermore, we confirmed that the UV-A-induced transcriptions of AP-1 signalling pathway were regulated by sargachromenol treatment in UV-A-irradiated dermal fibroblasts. © 2012 John Wiley & Sons A/S.

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

PubMed

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

2017-10-01

Nighttime ultraviolet (UV) radiation, if applied properly, has a significant potential for management of powdery mildews in many crop species. In this study, the role of growth light duration, irradiance, a combination of both (daily light integral) and light spectral quality (blue or red) on the efficacy of UV treatments against powdery mildew caused by Podosphaera xanthii and the growth performance of cucumber plants was studied in growth chambers. Increasing daily light integral provided by high-pressure sodium lamps (HPS) decreased efficacy of nighttime UV treatments against P. xanthii, but it increased plant growth. Furthermore, the efficacy of nighttime UV decreased when day length was increased from 16 to 20h at a constant daily light integral. The efficacy of nighttime UV increased if red light was applied after UV treatment, showing the possibility of day length extension without reducing the effect of UV. Increasing the dose of blue light during daytime reduced the efficacy of nighttime UV in controlling the disease, whereas blue deficient growth light (<6% of blue) caused UV mediated curling of young leaves. Furthermore, application of blue light after nighttime UV reduced its disease control efficacy. This showed the importance of maintaining a minimum of blue light in the growth light before nighttime UV treatment. Findings from this study showed that optimization of nighttime UV for management of powdery mildew is dependent on the spectral composition of the photosynthetically active radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous atrazine degradation and E. coli inactivation by simulated solar photo-Fenton-like process using persulfate.

PubMed

Garkusheva, Natalya; Matafonova, Galina; Tsenter, Irina; Beck, Sara; Batoev, Valeriy; Linden, Karl

2017-07-29

This work evaluated the feasibility of a photo-Fenton-like process using persulfate (PS) and ferrous iron (Fe 2+ ) under simulated solar radiation for degrading the herbicide atrazine (ATZ, 6-Chloro-N-ethyl-N'-isopropyl-1,3,5-triazine-2,4-diamine) and inactivating E. coli. Milli Q water, lake water, and diluted wastewater effluents were spiked both simultaneously and separately with ATZ (4 mg/L) and E. coli (10 5 CFU/mL), and exposed to treatment. A method for determining the average irradiance throughout the water media in the UV(A+B) range of the Xe lamp emission was developed for bench-scale experiments. These values were used to calculate the UV(A+B) fluences and the solar UV(A+B) energy doses per unit of volume (Q UV(A+B) , kJ/L). The obtained kinetic data were presented versus energy dose. Treatment of lake water at near-neutral pH was ineffective via the photo-Fenton-like process, attaining only 20% ATZ removal and 1-log reduction of E. coli. In Milli Q water and wastewater, the complete degradation of ATZ in the absence of bacteria was observed at an average energy dose of 1.5 kJ/L (60 min), while in the presence of cells the degradation efficiency was ∼60%. When ATZ was present, E. coli inactivation was also affected in Milli Q water, with 1.4-log reduction (93%) at a dose of 1.6 kJ/L (60 min), whereas in wastewater complete inactivation was achieved at a lower dose of 1.3 kJ/L (45 min). The energy requirements on a Q UV(A+B) basis for simultaneous 90% ATZ removal and 99.99% E. coli inactivation in Milli Q water and wastewater were shown to be less than 10 kJ/L. This suggests the solar/PS/Fe 2+ system is promising for simultaneous treatment and disinfection of wastewater effluents.

Radiation Induced Degradation of the White Thermal Control Paints Z-93 and Z-93P

NASA Technical Reports Server (NTRS)

Edwards, D. L.; Zwiener, J. M.; Wertz, G. E.; Vaughn, J. A.; Kamenetzky, R. R.; Finckenor, M. M.; Meshishnek, M. J.

1996-01-01

This paper details a comparison analysis of the zinc oxide pigmented white thermal control paints Z-93 and Z-93P. Both paints were simultaneously exposed to combined space environmental effects and analyzed using an in-vacuo reflectance technique. The dose applied to the paints was approximately equivalent to 5 years in a geosynchronous orbit. This comparison analysis showed that Z-93P is an acceptable substitute for Z-93. Irradiated samples of Z-93 and Z-93P were subjected to additional exposures of ultraviolet (UV) radiation and analyzed using the in-vacuo reflectance technique to investigate UV activated reflectance recovery. Both samples showed minimal UV activated reflectance recovery after an additional 190 equivalent sun hour (ESH) exposure. Reflectance response utilizing nitrogen as a repressurizing gas instead of air was also investigated. This investigation found the rates of reflectance recovery when repressurized with nitrogen are slower than when repressurized with air.

Radiation Induced Degradation of White Thermal Control Paint

NASA Technical Reports Server (NTRS)

Edwards, D. L.; Zwiener, J. M.; Wertz, G. E.; Vaughn, Jason A.; Kamenetzky, Rachel R.; Finckenor, M. M.; Meshishnek, M. J.

1999-01-01

This paper details a comparison analysis of the zinc-oxide pigmented white thermal control paints Z-93 and Z-93P. Both paints were simultaneously exposed to combined space environmental effects and analyzed using an in-vacuo reflectance technique. The dose applied to the paints was approximately equivalent to 5 yr in a geosynchronous orbit. This comparison analysis showed that Z-93P is an acceptable substitute for Z-93. Irradiated samples of Z-93 and Z-93P were subjected to additional exposures of ultraviolet (UV) radiation and analyzed using the in-vacuo reflectance technique to investigate UV activated reflectance recovery. Both samples showed minimal UV activated reflectance recovery after an additional 190 equivalent Sun hour (ESH) exposure. Reflectance response utilizing nitrogen as a repressurizing gas instead of air was also investigated. This investigation found the rates of reflectance recovery when repressurized with nitrogen are slower than when repressurized with air.

Improvement in Flavonoids and Phenolic Acids Production and Pharmaceutical Quality of Sweet Basil (Ocimum basilicum L.) by Ultraviolet-B Irradiation.

PubMed

Ghasemzadeh, Ali; Ashkani, Sadegh; Baghdadi, Ali; Pazoki, Alireza; Jaafar, Hawa Z E; Rahmat, Asmah

2016-09-09

Sweet basil (Ocimum basilicum Linnaeus) is aromatic herb that has been utilized in traditional medicine. To improve the phytochemical constituents and pharmaceutical quality of sweet basil leaves, ultraviolet (UV)-B irradiation at different intensities (2.30, 3.60, and 4.80 W/m²) and durations (4, 6, 8, and 10-h) was applied at the post-harvest stage. Total flavonoid content (TFC) and total phenolic content (TPC) were measured using spectrophotometric method, and individual flavonoids and phenolic acids were identified using ultra-high performance liquid chromatography. As a key enzyme for the metabolism of flavonoids, chalcone synthase (CHS) activity, was measured using a CHS assay. Antioxidant activity and antiproliferative activity of extracts against a breast cancer cell line (MCF-7) were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, respectively. UV-B irradiation at an intensity of 3.60 W/m² increased TFC approximately 0.85-fold and also increased quercetin (0.41-fold), catechin (0.85-fold), kaempferol (0.65-fold) rutin (0.68-fold) and luteolin (1.00-fold) content. The highest TPC and individual phenolic acid (gallic acid, cinnamic acid and ferulic acid) was observed in the 3.60 W/m² of UV-B treatment. Cinnamic acid and luteolin were not detected in the control plants, production being induced by UV-B irradiation. Production of these secondary metabolites was also significantly influenced by the duration of UV-B irradiation. Irradiation for 8-h led to higher TFC, TPC and individual flavonoids and phenolic acids than for the other durations (4, 8, and 10-h) except for cinnamic acid, which was detected at higher concentration when irradiated for 6-h. Irradiation for 10-h significantly decreased the secondary metabolite production in sweet basil leaves. CHS activity was induced by UV-B irradiation and highest activity was observed at 3.60 W/m² of UV-B irradiation. UV-B treated leaves presented the highest DPPH activity and antiproliferative activity with a half-maximal inhibitory concentration (IC50) value of 56.0 and 40.8 µg/mL, respectively, over that of the control plants (78.0 and 58.2 µg/mL, respectively). These observations suggest that post-harvest irradiation with UV-B can be considered a promising technique to improve the healthy-nutritional and pharmaceutical properties of sweet basil leaves.

PAR modulation of the UV-dependent levels of flavonoid metabolites in Arabidopsis thaliana (L.) Heynh. leaf rosettes: cumulative effects after a whole vegetative growth period.

PubMed

Götz, Michael; Albert, Andreas; Stich, Susanne; Heller, Werner; Scherb, Hagen; Krins, Andreas; Langebartels, Christian; Seidlitz, Harald K; Ernst, Dieter

2010-07-01

Long-term effects of ultraviolet (UV) radiation on flavonoid biosynthesis were investigated in Arabidopsis thaliana using the sun simulators of the Helmholtz Zentrum München. The plants, which are widely used as a model system, were grown (1) at high photosynthetically active radiation (PAR; 1,310 micromol m(-2) s(-1)) and high biologically effective UV irradiation (UV-B(BE) 180 mW m(-2)) during a whole vegetative growth period. Under this irradiation regime, the levels of quercetin products were distinctively elevated with increasing UV-B irradiance. (2) Cultivation at high PAR (1,270 micromol m(-2) s(-1)) and low UV-B (UV-B(BE) 25 mW m(-2)) resulted in somewhat lower levels of quercetin products compared to the high-UV-B(BE) conditions, and only a slight increase with increasing UV-B irradiance was observed. On the other hand, when the plants were grown (3) at low PAR (540 micromol m(-2) s(-1)) and high UV-B (UV-B(BE) 180 mW m(-2)), the accumulation of quercetin products strongly increased from very low levels with increasing amounts of UV-B but the accumulation of kaempferol derivatives and sinapoyl glucose was less pronounced. We conclude (4) that the accumulation of quercetin products triggered by PAR leads to a basic UV protection that is further increased by UV-B radiation. Based on our data, (5) a combined effect of PAR and different spectral sections of UV radiation is satisfactorily described by a biological weighting function, which again emphasizes the additional role of UV-A (315-400 nm) in UV action on A. thaliana.

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

PubMed

Chen, Yi-Ping

2009-07-01

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

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

UV testing of solar cells: Effects of antireflective coating, prior irradiation, and UV source

NASA Technical Reports Server (NTRS)

Meulenberg, A.

1993-01-01

Short-circuit current degradation of electron irradiated double-layer antireflective-coated cells after 3000 hours ultraviolet (UV) exposure exceeds 3 percent; extrapolation of the data to 10(exp 5) hours (11.4 yrs.) gives a degradation that exceeds 10 percent. Significant qualitative and quantitative differences in degradation were observed in cells with double- and single-layer antireflective coatings. The effects of UV-source age were observed and corrections were made to the data. An additional degradation mechanism was identified that occurs only in previously electron-irradiated solar cells since identical unirradiated cells degrade to only 6 +/- 3 percent when extrapolated 10(exp 5) hours of UV illumination.

Photocatalytic removal of SO2 using natural zeolite modified by TiO2 and polyoxypropylene surfactant.

PubMed

Amini, Nasibeh; Soleimani, Mohsen; Mirghaffari, Nourollah

2018-01-25

Air pollution due to emission of various hazardous gases such as SO 2 into the atmosphere and its control is an important environmental issue. Application of photocatalysts is considered as a suitable process to control the gaseous pollutants. In this study, the efficiency of clinoptilolite as a natural zeolite (Ze) modified by TiO 2 (Ze-Ti) and a polymeric surfactant polyoxypropylene (Ze-Ti-POP) for removal of SO 2 was investigated. The nanocomposites were characterized by SEM, EDX, and BET analyses. The photocatalytic oxidation experiments of SO 2 by the nanocomposites and natural zeolite were done under UV irradiation with initial SO 2 concentration of 500 ppm in a photoreactor. The effects of different factors including reaction time, catalyst dose, UV irradiation intensity, humidity content, and calcination temperature and dose of TiO 2 were studied. The modification of clinoptilolite by TiO 2 and POP increased considerably the BET specific surface area of the nanocomposites. The results showed that maximum removal efficiencies of SO 2 by Ze-Ti and Ze-Ti-POP under the optimum experimental conditions were 82.1 and 87.4%, respectively. Adsorption kinetics data well fitted with the Langmuir-Hinshelwood model. Moreover, reusing of nanocomposites after three regeneration cycles indicated that application of Ze-Ti and Ze-Ti-POP nanocomposites could be a promising approach for SO 2 removal. Graphical abstract ᅟ.

UV Light-Assisted Synthesis of Highly Efficient Pd-Based Catalyst over NiO for Hydrogenation of o-Chloronitrobenzene

PubMed Central

Jiang, Weidong; Xu, Bin; Fan, Guangyin; Zhang, Kaiming; Xiang, Zhen; Liu, Xiaoqiang

2018-01-01

Supported Pd-based catalyst over active nickel oxide (NiO) was repared using the impregnation method companying with UV-light irradiation. Moreover, the catalytic performance of the obtained Pd-based catalysts was evaluated towards the hydrogenation of o-chloronitrobenzene (o-CNB). Observations indicate that the as-prepared UV-irradiated Pd/NiO catalyst with a mole fraction 0.2% (0.2%Pd/NiO) has higher activity and selectivity in the o-CNB hydrogenation. Especially, UV-light irradiation played a positive role in the improvement of catalytic activity of 0.2%Pd/NiO catalyst, exhibiting an excess 11-fold activity superiority in contrast with non-UV-irradiated 0.2%Pd/NiO catalyst. In addition, it was investigated that effects of varied factors (i.e., reaction time, temperature, o-CNB/Pd ratio, Pd loading, hydrogen pressure) on the selective hydrogenation of ο-CNB catalyzed by UV-irradiated 0.2%Pd/NiO catalyst. Under the reaction conditions of 60 °C, 0.5 h, 1 MPa H2 pressure, 100% conversion of o-CNB, and 81.1% o-CAN selectivity were obtained, even at high molar ratio (8000:1) of o-CNB to Pd. PMID:29662004

Single-strand breakage of DNA in UV-irradiated uvrA, uvrB, and uvrC mutants of Escherichia coli.

PubMed Central

Tang, M S; Ross, L

1985-01-01

We transduced the uvrA6, uvrB5, uvrC34, and uvrC56 markers from the original mutagenized strains into an HF4714 background. Although in the original mutagenized strains uvrA6 cells are more UV sensitive than uvrB5 and uvrC34 cells, in the new background no significant difference in UV sensitivity is observed among uvrA6, uvrB5, and uvrC34 cells. No DNA single-strand breaks are detected in UV-irradiated uvrA6 or uvrB5 cells, whereas in contrast a significant number of single-strand breaks are detected in both UV-irradiated uvrC34 and uvrC56 cells. The number of single-strand breaks in these cells reaches a plateau at 20-J/m2 irradiation. Since these single-strand breaks can be detected by both alkaline sucrose and neutral formamide-sucrose gradient sedimentation, we concluded that the single-strand breaks observed in UV-irradiated uvrC cells are due to phosphodiester bond interruptions in DNA and are not due to apurinic/apyrimidinic sites. PMID:3882671

UV Light-Assisted Synthesis of Highly Efficient Pd-Based Catalyst over NiO for Hydrogenation of o-Chloronitrobenzene.

PubMed

Jiang, Weidong; Xu, Bin; Fan, Guangyin; Zhang, Kaiming; Xiang, Zhen; Liu, Xiaoqiang

2018-04-14

Supported Pd-based catalyst over active nickel oxide (NiO) was repared using the impregnation method companying with UV-light irradiation. Moreover, the catalytic performance of the obtained Pd-based catalysts was evaluated towards the hydrogenation of o -chloronitrobenzene ( o -CNB). Observations indicate that the as-prepared UV-irradiated Pd/NiO catalyst with a mole fraction 0.2% (0.2%Pd/NiO) has higher activity and selectivity in the o -CNB hydrogenation. Especially, UV-light irradiation played a positive role in the improvement of catalytic activity of 0.2%Pd/NiO catalyst, exhibiting an excess 11-fold activity superiority in contrast with non-UV-irradiated 0.2%Pd/NiO catalyst. In addition, it was investigated that effects of varied factors (i.e., reaction time, temperature, o -CNB/Pd ratio, Pd loading, hydrogen pressure) on the selective hydrogenation of ο -CNB catalyzed by UV-irradiated 0.2%Pd/NiO catalyst. Under the reaction conditions of 60 °C, 0.5 h, 1 MPa H₂ pressure, 100% conversion of o -CNB, and 81.1% o -CAN selectivity were obtained, even at high molar ratio (8000:1) of o -CNB to Pd.

Projected changes in erythemal and vitamin D effective irradiance over northern-hemisphere high latitudes.

PubMed

Fountoulakis, I; Bais, A F

2015-07-01

Simulations of the monthly mean noon UV index and the effective dose for the production of vitamin D in the human skin have been performed for local noon for the latitude band 55°N-85°N using a radiative transfer model. The magnitude and spatial distribution of the changes estimated for the two quantities between the past (1955-1965 mean), the present (2010-2020 mean) and the future (2085-2095 mean) are discussed and the main drivers for these changes are identified. The irradiance simulations are based on simulations and projections of total ozone, surface reflectivity and aerosol optical depth derived from models used in the fifth phase of the Coupled Model Intercomparison Project (CMIP-5). The cloud modification factor is also derived from the CMIP-5 models and used to account for the effects of cloudiness. Simulations have been derived for two socioeconomic scenarios: the moderate RCP 4.5 and the extreme RCP 8.5. For the future, the two quantities are projected to be generally lower than in the past and the present, mainly due to the projected super-recovery of stratospheric ozone and reduced surface reflectivity. Although the greatest changes are projected over the Arctic Ocean and do not directly affect humans, the changes over land are also important. Over land, the greatest changes are found in northern Asia, Greenland and the north-east shores of Canada and Alaska. The greatest reductions over land are projected for April under all skies, locally reaching ∼30% for the noon UV index and ∼50% for the noon effective UV dose for the production of vitamin D.

Resistance of the genome of Escherichia coli and Listeria monocytogenes to irradiation evaluated by the induction of cyclobutane pyrimidine dimers and 6-4 photoproducts using gamma and UV-C radiations

NASA Astrophysics Data System (ADS)

Beauchamp, S.; Lacroix, M.

2012-08-01

The effect of gamma and UV-C irradiation on the production of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4 PPs) in DNA was investigated to compare the natural resistance of the genome of a Gram-positive bacterium and a Gram-negative bacterium against irradiation. Solution of pure DNA and bacterial strains Listeria monocytogenes and Escherichia coli were irradiated using gamma and UV-C rays. Extracted DNA from bacteria and pure DNA samples were then analysed by ELISA using anti-CPDs and anti-6-4 PPs monoclonal antibodies. The results show that gamma rays, as well as UV-C rays, induce the formation of CPDs and 6-4 PPs in DNA. During UV-C irradiation, the three samples showed a difference in their sensitivity against formation of CPDs (P≤0.05). Pure DNA was the most sensitive while the genome of L. monocytogenes was the most resistant. Also during UV-C irradiation, the genome of L. monocytogenes was the only one to show a significant resistance against formation of 6-4 PPs (P≤0.05). During gamma irradiation, for both types of lesion, pure DNA and the genome of E. coli did not show significant difference in their sensitivity (P>0.05) while the genome of L. monocytogenes showed a resistance against formation of CPDs and 6-4 PPs.

Naked eye detection of mutagenic DNA photodimers using gold nanoparticles.

PubMed

Kim, Joong Hyun; Chung, Bong Hyun

2011-01-15

We developed a method to detect mutagenic DNA photodimers by the naked eye using gold nanoparticles. The stability of gold nanoparticles in a high ionic strength solution is maintained by straight ssDNA adsorbed physically on the AuNPs. However, we found that UV-irradiated DNA was less adsorptive onto gold nanoparticles because of a conformational change of UV-irradiated DNA. The accumulated deformation of the DNA structure by multiple-dimer formation triggered aggregation of the gold nanoparticles mixed with the UV-irradiated DNA and thus red to purple color changes of the mixture, which allowed colorimetric detection of the DNA photodimers by the naked eye. No fragmented mass and reactive oxygen species production under the UVB irradiation confirmed that the aggregation of gold nanoparticles was solely attributed to the accumulated deformation of the UV irradiated DNA. The degree of gold nanoparticles-aggregation was dependent on the UVB irradiated time and base compositions of the UV-irradiated oligonucleotides. In addition, we successfully demonstrated how to visually qualify the photosensitizing effect of chemical compounds in parallel within only 10 min by applying this new method. Since our method does not require any chemical or biochemical treatments or special instruments for purifying and qualifying the DNA photolesions, it should provide a feasible tool for the studies of the UV-induced mutagenic or carcinogenic DNA dimers and accelerate screening of a large number of drug candidates. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Effect of UV irradiation on Echinaceae purpureae interactions with free radicals examined by an X-band (9.3 GHz) EPR spectroscopy.

PubMed

Ramos, Paweł; Pilawa, Barbara

The effect of UVA (315-400 nm) irradiation on Echinaceae purpureae interactions with free radicals was examined by the use of electron paramagnetic resonance (EPR) spectroscopy. The changes of antioxidant properties of E. purpureae with time of UV irradiation from 10 to 110 min (10 min steps) were determined. DPPH as the paramagnetic reference was used in this study. Changes of EPR signals of the reference after interactions with nonirradiated and UV-irradiated E. purpureae were detected. Interactions of the tested E. purpureae samples caused decrease of the EPR signal of DPPH as the result of its antioxidant properties. The decrease of the amplitude of EPR line of DPPH was lower for interactions with UV-irradiated E. purpureae . EPR examination confirmed antioxidant properties of E. purpureae . The weaker antioxidant properties of E. purpureae after UV irradiation were pointed out. E. purpureae should be storage in the dark. The tests bring to light usefulness of electron paramagnetic resonance with microwave frequency of 9.3 GHz (an X-band) in examination of storage conditions of pharmacological herbs.

Effect of UV irradiation on different types of luminescence of SrAl2 O4 :Eu,Dy phosphors.

PubMed

Jha, Piyush

2016-11-01

This paper reports the luminescence behavior of Sr 0.097 Al 2 O 4 :Eu 0.01 ,Dy 0.02 phosphors under UV-irradiation. The effect of UV-irradiation on afterglow (AG), thermoluminescence (TL) and mechanoluminescence (ML) of Sr 0.097 Al 2 O 4 :Eu 0.01 ,Dy 0.02 phosphors is investigated. The space group of Sr 0.097 Al 2 O 4 :Eu 0.01 ,Dy 0.02 phosphors is monoclinic P2 1 . The prepared phosphors exhibit a long AG, intense TL and ML. It is found that the AG, ML intensity and TL increase with increasing duration of irradiation time. The ML intensity decreases with successive impact of the load onto the phosphors, whereby the diminished ML intensity can be recovered by UV-irradiation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

A method to generate surface UV radiation maps over Europe using GOME, Meteosat, and ancillary geophysical data

NASA Astrophysics Data System (ADS)

Verdebout, Jean

2000-02-01

This paper presents a method for generating surface ultraviolet (UV) radiation maps over Europe, with a spatial resolution of 0.05°, and potentially on a half-hour basis. The UV irradiance is obtained by interpolation in a look-up table (LUT), the entries of which are solar zenith angle, total column ozone amount, cloud liquid water thickness, near-surface horizontal visibility, surface elevation, and UV albedo. Both satellite (Meteosat, GOME) and nonsatellite (synoptic observations, meteorological model results, digital elevation model) data are exploited to assign values to the influencing factors. With the help of another LUT simulating the visible signal, Meteosat data are processed to retrieve the cloud liquid water thickness. The radiative transfer calculations are performed with the UVspec code. A preliminary step consists in generating an effective surface Meteosat albedo map from a series of 10 consecutive days. In this process the well-known difficulty of distinguishing clouds from snow-covered surfaces is encountered. An attempt is made to partially resolve the ambiguity by using the Meteosat infrared channel and modeled snow cover data. After additional empirical cloud filtering, the effective albedo map is used as a baseline to estimate the cloud liquid water thickness. The UV surface albedo is assigned uniform values for land and sea/ocean, except in the presence of snow. In this case it is given a value proportional to the Meteosat effective albedo. The total column ozone is extracted from the level 3 GOME products. The aerosol optical thickness is mapped by gridding the daily measurements performed by ˜1000 ground stations. The digital elevation model is the GTOPO30 data set from the U.S. Geological Survey. European wide UV dose rate maps are presented for one day in April 1997, and the influence of the various factors is illustrated. A daily integrated dose map was also generated using 27 Meteosat acquisitions at half-hour intervals on the same day. The dose map produced in this way takes into account the evolution of the cloud field and is thought to be more accurate than if it were estimated from one data take, in particular at the relatively high spatial resolution of the product. Finally, a preliminary comparison of modeled dose rate and daily dose with measurements performed with a ground instrument is discussed.

Structural and optical properties of CuO in zinc phosphate glasses and effects of gamma irradiation

NASA Astrophysics Data System (ADS)

Ouis, M. A.; ElBatal, H. A.; Abdelghany, A. M.; Hammad, Ahmed H.

2016-01-01

Collective optical and infrared measurements have been employed to investigate the state of increasing copper ions in host 0.5ZnO-0.5P2O5 glass composition. The same spectral measurements were repeated after gamma irradiation with a dose of 20 and 80 KGy. Optical absorption spectra reveal strong UV absorption due to trace ferric ions present as unavoidable impurities within the chemicals used in the preparation of the glasses. Copper containing glasses show an additional broad visible-near infrared band due to distorted octahedrally coordinated Cu2+ ions which at high CuO contents exhibit splitting to several component absorption peaks. Gamma irradiation causes several variations between the response of the base host zinc phosphate glass and effect of increasing CuO. These changes are correlated with both the formation of induced defects through suggested photochemical reactions in the UV region and some shielding effects with increasing CuO in the visible-near infrared spectrum. Infrared absorption spectra reveal repetitive vibrational bands due to phosphate groups mainly from metaphosphate units and the spectra show some variations with the increase of CuO content visualize by the increase of the intensity of the mid broad band extending in the range 800-1500 cm-1.

The immune system and skin cancer.

PubMed

Yu, Sherry H; Bordeaux, Jeremy S; Baron, Elma D

2014-01-01

Carcinogenesis involves multiple mechanisms that disturb genomic integrity and encourage abnormal proliferation. The immune system plays an integral role in maintaining homeostasis and these mechanisms may arrest or enhance dysplasia. There exists a large body of evidence from organ transplantation literature supporting the significance of the immune suppression in the development of skin cancer. Nonmelanoma skin cancers are the most frequent neoplasms after organ transplantation, with organ transplant recipients having a 65-fold increase in squamous cell carcinoma incidence and 10-fold increase in basal cell carcinoma incidence. Similarly, UV-radiation (UVR) induced immunosuppression is correlated with the development of cutaneous malignancies in a dose-dependent manner. This was first shown several decades ago by Margaret Kripke, when transplanted tumors were rejected in mice with competent immune systems, but grew unchecked in immunosuppressed specimens. After UV exposure, chromophores initiate a cascade that leads to immunosuppression via derangement of Langerhans cells' antigen-presenting capacity. UV-irradiated Langerhans cells present antigens to Th2 cells, but fail to stimulate Th1 cells. A subset of T regulatory cells, specific for the antigen encountered after UVR, is also stimulated to proliferate. In general UV irradiation leads to a greater number of T regulatory cells and fewer effector T cells in the skin, shiftingthe balance from T-cell-mediated immunity to immunosuppression. These regulatory cells have the phenotype CD4+, CD25+, Foxp3+, CTLA-4+. These and many other changes in local immunity lead to a suppressed immune state, which allow for skin cancer development.

Analysis of DNA repair and protection in the Tardigrade Ramazzottius varieornatus and Hypsibius dujardini after exposure to UVC radiation.

PubMed

Horikawa, Daiki D; Cumbers, John; Sakakibara, Iori; Rogoff, Dana; Leuko, Stefan; Harnoto, Raechel; Arakawa, Kazuharu; Katayama, Toshiaki; Kunieda, Takekazu; Toyoda, Atsushi; Fujiyama, Asao; Rothschild, Lynn J

2013-01-01

Tardigrades inhabiting terrestrial environments exhibit extraordinary resistance to ionizing radiation and UV radiation although little is known about the mechanisms underlying the resistance. We found that the terrestrial tardigrade Ramazzottius varieornatus is able to tolerate massive doses of UVC irradiation by both being protected from forming UVC-induced thymine dimers in DNA in a desiccated, anhydrobiotic state as well as repairing the dimers that do form in the hydrated animals. In R. varieornatus accumulation of thymine dimers in DNA induced by irradiation with 2.5 kJ/m(2) of UVC radiation disappeared 18 h after the exposure when the animals were exposed to fluorescent light but not in the dark. Much higher UV radiation tolerance was observed in desiccated anhydrobiotic R. varieornatus compared to hydrated specimens of this species. On the other hand, the freshwater tardigrade species Hypsibius dujardini that was used as control, showed much weaker tolerance to UVC radiation than R. varieornatus, and it did not contain a putative phrA gene sequence. The anhydrobiotes of R. varieornatus accumulated much less UVC-induced thymine dimers in DNA than hydrated one. It suggests that anhydrobiosis efficiently avoids DNA damage accumulation in R. varieornatus and confers better UV radiation tolerance on this species. Thus we propose that UV radiation tolerance in tardigrades is due to the both high capacities of DNA damage repair and DNA protection, a two-pronged survival strategy.

Analysis of DNA Repair and Protection in the Tardigrade Ramazzottius varieornatus and Hypsibius dujardini after Exposure to UVC Radiation

PubMed Central

Horikawa, Daiki D.; Cumbers, John; Sakakibara, Iori; Rogoff, Dana; Leuko, Stefan; Harnoto, Raechel; Arakawa, Kazuharu; Katayama, Toshiaki; Kunieda, Takekazu; Toyoda, Atsushi; Fujiyama, Asao; Rothschild, Lynn J.

2013-01-01

Tardigrades inhabiting terrestrial environments exhibit extraordinary resistance to ionizing radiation and UV radiation although little is known about the mechanisms underlying the resistance. We found that the terrestrial tardigrade Ramazzottius varieornatus is able to tolerate massive doses of UVC irradiation by both being protected from forming UVC-induced thymine dimers in DNA in a desiccated, anhydrobiotic state as well as repairing the dimers that do form in the hydrated animals. In R. varieornatus accumulation of thymine dimers in DNA induced by irradiation with 2.5 kJ/m2 of UVC radiation disappeared 18 h after the exposure when the animals were exposed to fluorescent light but not in the dark. Much higher UV radiation tolerance was observed in desiccated anhydrobiotic R. varieornatus compared to hydrated specimens of this species. On the other hand, the freshwater tardigrade species Hypsibius dujardini that was used as control, showed much weaker tolerance to UVC radiation than R. varieornatus, and it did not contain a putative phrA gene sequence. The anhydrobiotes of R. varieornatus accumulated much less UVC-induced thymine dimers in DNA than hydrated one. It suggests that anhydrobiosis efficiently avoids DNA damage accumulation in R. varieornatus and confers better UV radiation tolerance on this species. Thus we propose that UV radiation tolerance in tardigrades is due to the both high capacities of DNA damage repair and DNA protection, a two-pronged survival strategy. PMID:23762256

Intercellular Adhesion Molecule 1 Knockout Abrogates Radiation Induced Pulmonary Inflammation

NASA Astrophysics Data System (ADS)

Hallahan, Dennis E.; Virudachalam, Subbulakshmi

1997-06-01

Increased expression of intercellular adhesion molecule 1 (ICAM-1; CD54) is induced by exposure to ionizing radiation. The lung was used as a model to study the role of ICAM-1 in the pathogenesis of the radiation-induced inflammation-like response. ICAM-1 expression increased in the pulmonary microvascular endothelium and not in the endothelium of larger pulmonary vessels following treatment of mice with thoracic irradiation. To quantify radiation-induced ICAM-1 expression, we utilized fluorescence-activated cell sorting analysis of anti-ICAM-1 antibody labeling of pulmonary microvascular endothelial cells from human cadaver donors (HMVEC-L cells). Fluorochrome conjugates and UV microscopy were used to quantify the fluorescence intensity of ICAM in the irradiated lung. These studies showed a dose- and time-dependent increase in ICAM-1 expression in the pulmonary microvascular endothelium. Peak expression occurred at 24 h, while threshold dose was as low as 2 Gy. To determine whether ICAM-1 is required for inflammatory cell infiltration into the irradiated lung, the anti-ICAM-1 blocking antibody was administered by tail vein injection to mice following thoracic irradiation. Inflammatory cells were quantified by immunofluorescence for leukocyte common antigen (CD45). Mice treated with the anti-ICAM-1 blocking antibody showed attenuation of inflammatory cell infiltration into the lung in response to ionizing radiation exposure. To verify the requirement of ICAM-1 in the inflammation-like radiation response, we utilized the ICAM-1 knockout mouse. ICAM-1 was not expressed in the lungs of ICAM-1-deficient mice following treatment with thoracic irradiation. ICAM-1 knockout mice had no increase in the inflammatory cell infiltration into the lung in response to thoracic irradiation. These studies demonstrate a radiation dose-dependent increase in ICAM-1 expression in the pulmonary microvascular endothelium, and show that ICAM-1 is required for inflammatory cell infiltration into the irradiated lung.

Inhibition and recovery of the replication of depurinated parvovirus DNA in mouse fibroblasts

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

Vos, J.M.; Avalosse, B.; Su, Z.Z.

Apurinic sites were introduced in the single-stranded DNA of parvovirus minute-virus-of-mice (MVM) and their effect on viral DNA synthesis was measured in mouse fibroblasts. Approximately one apurinic site per viral genome, is sufficient to block its replication in untreated cells. The exposure of host cells to a sublethal dose of UV-light 15 hours prior to virus infection, enhances their ability to support the replication of depurinated MVM. Cell preirradiation induces the apparent overcome of 10-15% of viral DNA replication blocks. These results indicate that apurinic sites prevent mammalian cells from replicating single-stranded DNA unless a recovery process is activated bymore » cell UV-irradiation.« less

Molecular mechanisms of green tea polyphenols with protective effects against skin photoaging.

PubMed

Roh, Eunmiri; Kim, Jong-Eun; Kwon, Jung Yeon; Park, Jun Seong; Bode, Ann M; Dong, Zigang; Lee, Ki Won

2017-05-24

Whereas green tea has historically been consumed in high quantities in Northeast Asia, its popularity is also increasing in many Western countries. Green tea is an abundant source of plant polyphenols exhibiting numerous effects that are potentially beneficial for human health. Accumulating evidence suggests that green tea polyphenols confer protective effects on the skin against ultraviolet (UV) irradiation-induced acceleration of skin aging, involving antimelanogenic, antiwrinkle, antioxidant, and anti-inflammatory effects as well as prevention of immunosuppression. Melanin pigmentation in the skin is a major defense mechanism against UV irradiation, but pigmentation abnormalities such as melasma, freckles, senile lentigines, and other forms of melanin hyperpigmentation can also cause serious health and aesthetic issues. Furthermore, UV irradiation initiates the degradation of fibrillar collagen and elastic fibers, promoting the process of skin aging through deep wrinkle formation and loss of tissue elasticity. UV irradiation-induced formation of free radicals also contributes to accelerated photoaging. Additionally, immunosuppression caused by UV irradiation plays an important role in photoaging and skin carcinogenesis. In this review, we summarize the current literature regarding the antimelanogenic, antiwrinkle, antioxidant, and immunosuppression preventive mechanisms of green tea polyphenols that have been demonstrated to protect against UV irradiation-stimulated skin photoaging, and gauge the quality of evidence supporting the need for clinical studies using green tea polyphenols as anti-photoaging agents in novel cosmeceuticals.

Sperm nuclear expansion and meiotic maturation in normal and gynogenetic eggs of the scallop, Chlamys farreri

NASA Astrophysics Data System (ADS)

Pan, Ying; Li, Qi; Yu, Ruihai; Wang, Rucai

2008-02-01

Sperm nuclear expansion, meiosis and the association of the male and female pronuclei leading to the four-cell stage in normal Chlamys farreri eggs were observed under a fluorescence microscope. The effects of ultraviolet (UV) irradiation on the fertilizing sperm were also examined. Both normal and UV-irradiated sperm nuclei enlarged at three distinct phases (phase A, metaphase I; phase B, polar body formation; and phase C, female pronuclear development and expansion) that were temporally correlated with meiotic process of the maternal chromosomes. Sperm nuclei underwent a rapid, initial enlargement during phase A, but condensed slightly during phase B, then re-enlarged during phase C. The effects of UV irradiation were not apparent during transformation of the sperm nucleus into a male pronucleus, and there was not any apparent effect on meiotic maturation and development of the female pronucleus. However, the rate of expansion of the UV-irradiated sperm nuclei and the size of male pronuclei were reduced apparently. Unlike the female pronucleus, the male pronucleus derived from sperm genome inactivated by UV irradiation did not form chromosomes, but became a dense chromatin body (DCB). At mitotic anaphase, DCB did not participate in the karyokinesis of the first cleavage as evidenced by chromosomal nondisjunction, demonstrating the effectiveness of using UV irradiation to induce gynogenetic scallop embryos.

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.

Increased formation of halomethanes during chlorination of chloramphenicol in drinking water by UV irradiation, persulfate oxidation, and combined UV/persulfate pre-treatments.

PubMed

Wenhai, Chu; Tengfei, Chu; Erdeng, Du; Deng, Yang; Yingqing, Guo; Naiyun, Gao

2016-02-01

Ultraviolet/persulfate (UV/PS) has been widely used to generate sulfate radicals for degradation of water organic pollutants in previous studies. However, its impacts on disinfection byproduct formation during post-chlorination of degraded compounds is unclear. The objective of this study was to evaluate the impacts of UV irradiation, PS oxidation, and the combined UV/PS advanced oxidation process (AOP) pre-treatments on halomethane formation during the following chlorination of chloramphenicol (CAP), a model antibiotic commonly found in wastewater-impacted water. Results showed that CAP could be transformed to more trichloromethane (TCM) than monochloromethane (MCM) and dichloromethane (DCM) in the presence of excess chlorine. UV photolysis, PS oxidation and UV/PS AOP all directly decomposed CAP to produce halomethanes (HMs) before post-chlorination. Moreover, UV and UV/PS pre-treatments both enhanced the formation of all the HMs in the subsequent chlorination. PS pre-oxidation decreased the TCM formation during post-chlorination, but increased the yields of MCM, DCM and total HMs. UV pre-irradiation significantly increased the bromide utilization of HMs, whereas UV/PS pre-oxidation decreased the bromine incorporation and utilization of HMs from the chlorination of CAP in a low-bromide water. UV irradiation, PS oxidation, and UV/PS AOP can inactivate pathogens and degrade organic pollutants, but this benefit should be weighed against a potential risk of the increased halomethane formation from degraded organic pollutants with and without post-chlorination. Copyright © 2015 Elsevier Inc. All rights reserved.

Activation of T-cell Protein-tyrosine Phosphatase Suppresses Keratinocyte Survival and Proliferation following UVB Irradiation*

PubMed Central

Lee, Hyunseung; Morales, Liza D.; Slaga, Thomas J.; Kim, Dae Joon

2015-01-01

Chronic exposure to UV radiation can contribute to the development of skin cancer by promoting protein-tyrosine kinase (PTK) signaling. Studies show that exposure to UV radiation increases the ligand-independent activation of PTKs and induces protein-tyrosine phosphatase (PTP) inactivation. In the present work, we report that T-cell PTP (TC-PTP) activity is stimulated during the initial response to UVB irradiation, which leads to suppression of keratinocyte cell survival and proliferation via the down-regulation of STAT3 signaling. Our results show that TC-PTP-deficient keratinocyte cell lines expressed a significantly increased level of phosphorylated STAT3 after exposure to low dose UVB. This increase corresponded with increased cell proliferation in TC-PTP-deficient keratinocytes following UVB irradiation. Loss of TC-PTP also reduced UVB-induced apoptosis. Corroborating with these results, overexpression of TC-PTP in keratinocyte cell lines yielded a decrease in phosphorylated STAT3 levels, which corresponded with a significant decrease in cell proliferation in response to low dose UVB. We demonstrate that TC-PTP activity was increased upon UVB exposure, and overexpression of TC-PTP in keratinocyte cell lines further increased its activity in the presence of UVB. Treatment of TC-PTP-deficient keratinocytes with the STAT3 inhibitor STA21 significantly reduced cell viability following UVB exposure in comparison with untreated TC-PTP-deficient keratinocytes, confirming that the effect of TC-PTP on cell viability is mediated by STAT3 dephosphorylation. Combined, our results indicate that UVB-mediated activation of TC-PTP plays an important role in the STAT3-dependent regulation of keratinocyte cell proliferation and survival. Furthermore, these results suggest that TC-PTP may be a novel potential target for the prevention of UVB-induced skin cancer. PMID:25406309

Visualization of UV exposure of the human body based on data from a scanning UV-measuring system.

PubMed

Hoeppe, P; Oppenrieder, A; Erianto, C; Koepke, P; Reuder, J; Seefeldner, M; Nowak, D

2004-09-01

In general, measurements of UV radition are related to horizontal surfaces, as in the case of the internationally standardized and applied UV index, for example. In order to obtain more relevant information on UV exposure of humans the new measuring system ASCARATIS (Angle SCAnning RAdiometer for determination of erythemally weighted irradiance on TIlted Surfaces) was developed and built. Three systems of ASCARATIS have been in operation at different locations in Bavaria for 3 years, providing erythemally weighted UV irradiation data for 27 differently inclined surfaces every 2 min. On the basis of these data virtual three-dimensional models of the human body surface consisting of about 20,000 triangles could be created and each of these triangles coloured according to its UV irradiation. This allowed the UV exposure of the human body to be visualized for any kind of body posture and spatial orientation on the basis of real measuring data. The results of the UV measurements on inclined surfaces have shown that measuring UV radiation on horizontal surfaces, as done routinely worldwide, often underestimates the UV exposure of the human skin. Especially at times of the day or year with low solar elevations the UV exposure of parts of the human skin can be many times higher than that of the horizontal surface. Examples of three-dimensional modelling of the human UV irradiation are shown for different times of the day and year, altitudes above sea level, body postures and genders. In these examples the UV "hotspots" can be detected and, among other things, used to inform and educate the public about UV radiation.

Quality assessment of solar UV irradiance measured with array spectroradiometers

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Quality assessment of solar UV irradiance measured with array spectroradiometers

NASA Astrophysics Data System (ADS)

Egli, L.; Gröbner, J.; Hülsen, G.; Bachmann, L.; Blumthaler, M.; Dubard, J.; Khazova, M.; Kift, R.; Hoogendijk, K.; Serrano, A.; Smedley, A. R. D.; Vilaplana, J.-M.

2015-12-01

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

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 .

[Epidemiology of occupational skin cancer due to UV-irradiation].

PubMed

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

2012-10-01

Skin cancer induced by occupational UV-irradiation is not an official occupational disease number in the appendix of the German ordinance on occupational diseases (Berufskrankheitenverordnung (BKV) but can be recognized as a "virtually" occupational disease according to § 9 (2) of the 7th book of the German Social Code (SGB VII). Epidemiological studies have demonstrated a positive, statistically significant and relevant association between occupational UV-irradiation and the risk of squamous cell carcinoma (SCC) and actinic keratoses (AK). Outdoor workers have on average a 100% higher risk to develop SCC compared to the general population. Therefore, the prerequisites for a new occupational disease are fulfilled and SCC and AK should be reported as an occupational disease if an additional 40% occupationally-related UV-irradiation is documented and the clinical criteria are typical for work- related skin cancer. Epidemiologic evidence also indicates a significant association between work-related UV-irradiation and basal cell carcinoma (BCC) risk: however the results are less consistent and the association is weaker than with SCC. There is an urgent need for further studies in outdoor workers on BCC and lentigo maligna melanoma.

UV-observations with a Brewer spectrophotometer at Hohenpeissenberg

NASA Technical Reports Server (NTRS)

Vandersee, Winfried; Koehler, U.

1994-01-01

Regular spectral UV-B measurements with a Brewer spectrophotometer have been performed at Hohenpeissenberg since 1990. Intercomparison of the Brewer instrument with other UV-B monitoring devices have shown agreement to within plus or minus 10 percent. Comparisons of UV-B spectra measured on fair weather days reveal the well known increasing influence of ozone on UV-B irradiance with decreasing wavelengths. The integral amplification factor the erythemal irradiance reaches values up to 2.8, which can be diminished by increasing turbidity. The influence of cirrus cloud on the UV-B is also shown.

DNA repair factor XPC is modified by SUMO-1 and ubiquitin following UV irradiation

PubMed Central

Wang, Qi-En; Zhu, Qianzheng; Wani, Gulzar; El-Mahdy, Mohamed A.; Li, Jinyou; Wani, Altaf A.

2005-01-01

Nucleotide excision repair (NER) is the major DNA repair process that removes diverse DNA lesions including UV-induced photoproducts. There are more than 20 proteins involved in NER. Among them, XPC is thought to be one of the first proteins to recognize DNA damage during global genomic repair (GGR), a sub-pathway of NER. In order to study the mechanism through which XPC participates in GGR, we investigated the possible modifications of XPC protein upon UV irradiation in mammalian cells. Western blot analysis of cell lysates from UV-irradiated normal human fibroblast, prepared by direct boiling in an SDS lysis buffer, showed several anti-XPC antibody-reactive bands with molecular weight higher than the original XPC protein. The reciprocal immunoprecipitation and siRNA transfection analysis demonstrated that XPC protein is modified by SUMO-1 and ubiquitin. By using several NER-deficient cell lines, we found that DDB2 and XPA are required for UV-induced XPC modifications. Interestingly, both the inactivation of ubiquitylation and the treatment of proteasome inhibitors quantitatively inhibited the UV-induced XPC modifications. Furthermore, XPC protein is degraded significantly following UV irradiation in XP-A cells in which sumoylation of XPC does not occur. Taken together, we conclude that XPC protein is modified by SUMO-1 and ubiquitin following UV irradiation and these modifications require the functions of DDB2 and XPA, as well as the ubiquitin–proteasome system. Our results also suggest that at least one function of UV-induced XPC sumoylation is related to the stabilization of XPC protein. PMID:16030353

UV exposure of elementary school children in five Japanese cities.

PubMed

Ono, Masaji; Munakata, Nobuo; Watanabe, Shaw

2005-01-01

A 1 week UV-exposure measurement and outdoor-activity pattern survey was conducted for elementary school children for four seasons at five sites in Japan, i.e. Sapporo (43 degrees 05' N, altitude 40 m), Tsukuba (36 degrees 05' N, 20 m), Tokyo (35 degrees 40' N, 45 m), Miyazaki (31 degrees 60' N, 40 m) and Naha (26 degrees 10' N, 5 m), and UV exposure was measured directly and estimated using outdoor-activity records. The study site with largest UV exposure was Miyazaki, a southern rural area. Comparing the results for boys and girls, UV exposure was larger in boys. UV exposure was large in spring and summer and small in winter. The total amount of UV exposure in spring and summer contributed 57.7-73.4% of total exposure for the year. As a whole, 8.1% and 1.8% of the schoolchildren were exposed to more than 1 minimum erythemal dose (MED) and 2 MED of solar UV in a day, respectively. The estimated yearly UV exposure ranged from 49 207 J/m2 in Miyazaki to 31 520 J/m2 in Tsukuba. The actual UV exposure correlated to potential UV exposure, estimated using outdoor-activity records and ambient UV irradiance, but the ratio differed by season and site. The yearly average of percent UV exposure to ambient UV on a horizontal plane ranged from 9.9% in Tokyo to 4.0% in Naha. In the questionnaire survey on outdoor-activity pattern, a short question "How long did you spend time outdoors between 0900 and 1500 h?" gives the best estimates of UV exposure.

UV-induced replication arrest in the xeroderma pigmentosum variant leads to DNA double-strand breaks, γ-H2AX formation, and Mre11 relocalization

PubMed Central

Limoli, Charles L.; Giedzinski, Erich; Bonner, William M.; Cleaver, James E.

2002-01-01

UV-induced replication arrest in the xeroderma pigmentosum variant (XPV) but not in normal cells leads to an accumulation of the Mre11/Rad50/Nbs1 complex and phosphorylated histone H2AX (γ-H2AX) in large nuclear foci at sites of stalled replication forks. These complexes have been shown to signal the presence of DNA damage, in particular, double-strand breaks (DSBs). This finding suggests that UV damage leads to the formation of DSBs during the course of replication arrest. After UV irradiation, XPV cells showed a fluence-dependent increase in the yield of γ-H2AX foci that paralleled the production of Mre11 foci. The percentage of foci-positive cells increased rapidly (10–15%) up to fluences of 10 J⋅m−2 before saturating at higher fluences. Frequencies of γ-H2AX and Mre11 foci both reached maxima at 4 h after UV irradiation. This pattern contrasts sharply to the situation observed after x-irradiation, where peak levels of γ-H2AX foci were found to precede the formation of Mre11 foci by several hours. The nuclear distributions of γ-H2AX and Mre11 were found to colocalize spatially after UV- but not x-irradiation. UV-irradiated XPV cells showed a one-to-one correspondence between Mre11 and γ-H2AX foci-positive cells. These results show that XPV cells develop DNA DSBs during the course of UV-induced replication arrest. These UV-induced foci occur in cells that are unable to carry out efficient bypass replication of UV damage and may contribute to further genetic variation. PMID:11756691

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.

Spectral properties of condensed phases of disulfur monoxide, polysulfur oxide, and irradiated sulfur. [in planetary atmospheres

NASA Technical Reports Server (NTRS)

Hapke, Bruce; Graham, Francis

1989-01-01

The spectral reflectances of S2O, as well as the polysulfur oxide (PSO) condensate dissociation products of SO2 and condensates of elemental sulfur irradiated with UV light and X-rays, have been ascertained in the 200-1700 nm range with a view to the relevance of these compounds to the interpretation of planetary data. While S2O is a dark red solid, PSO is a pale yellow one that absorbs strongly in the UV but exhibits no bands in either the visible or near IR. Elemental S produces strong bands in the UV, and while it is normally white at room temperature, UV irradiation causes it to turn yellow. X-ray irradiation of S turns it orange.

Activation of Peroxisome Proliferator-Activated Receptor Alpha Improves Aged and UV-Irradiated Skin by Catalase Induction

PubMed Central

Shin, Mi Hee; Lee, Se-Rah; Kim, Min-Kyoung; Shin, Chang-Yup

2016-01-01

Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear hormone receptor involved in the transcriptional regulation of lipid metabolism, fatty acid oxidation, and glucose homeostasis. Its activation stimulates antioxidant enzymes such as catalase, whose expression is decreased in aged human skin. Here we investigated the expression of PPARα in aged and ultraviolet (UV)-irradiated skin, and whether PPARα activation can modulate expressions of matrix metalloproteinase (MMP)-1 and procollagen through catalase regulation. We found that PPARα mRNA level was significantly decreased in intrinsically aged and photoaged human skin as well as in UV-irradiated skin. A PPARα activator, Wy14643, inhibited UV-induced increase of MMP-1 and decrease of procollagen expression and caused marked increase in catalase expression. Furthermore, production of reactive oxygen species (ROS) was suppressed by Wy14643 in UV-irradiated and aged dermal fibroblasts, suggesting that the PPARα activation-induced upregulation of catalase leads to scavenging of ROS produced due to UV irradiation or aging. PPARα knockdown decreased catalase expression and abolished the beneficial effects of Wy14643. Topical application of Wy14643 on hairless mice restored catalase activity and prevented MMP-13 and inflammatory responses in skin. Our findings indicate that PPARα activation triggers catalase expression and ROS scavenging, thereby protecting skin from UV-induced damage and intrinsic aging. PMID:27611371

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.

UV-activated 7-dehydrocholesterol-coated titanium implants promote differentiation of human umbilical cord mesenchymal stem cells into osteoblasts.

PubMed

Satué, María; Ramis, Joana M; Monjo, Marta

2016-01-01

Vitamin D metabolites are essential for bone regeneration and mineral homeostasis. The vitamin D precursor 7-dehydrocholesterol can be used after UV irradiation to locally produce active vitamin D by osteoblastic cells. Furthermore, UV-irradiated 7-dehydrocholesterol is a biocompatible coating for titanium implants with positive effects on osteoblast differentiation. In this study, we examined the impact of titanium implants surfaces coated with UV-irradiated 7-dehydrocholesterol on the osteogenic differentiation of human umbilical cord mesenchymal stem cells. First, the synthesis of cholecalciferol (D3) was achieved through the incubation of the UV-activated 7-dehydrocholesterol coating for 48 h at 23℃. Further, we investigated in vitro the biocompatibility of this coating in human umbilical cord mesenchymal stem cells and its potential to enhance their differentiation towards the osteogenic lineage. Human umbilical cord mesenchymal stem cells cultured onto UV-irradiated 7-dehydrocholesterol-coated titanium implants surfaces, combined with osteogenic supplements, upregulated the gene expression of several osteogenic markers and showed higher alkaline phosphatase activity and calcein blue staining, suggesting increased mineralization. Thus, our results show that the use of UV irradiation on 7-dehydrocholesterol -treated titanium implants surfaces generates a bioactive coating that promotes the osteogenic differentiation of human umbilical cord mesenchymal stem cells, with regenerative potential for improving osseointegration in titanium-based bone anchored implants. © The Author(s) 2015.

Endonuclease from Micrococcus luteus Which Has Activity Toward Ultraviolet-Irradiated Deoxyribonucleic Acid: Its Action on Transforming Deoxyribonucleic Acid

PubMed Central

Setlow, R. B.; Setlow, Jane K.; Carrier, W. L.

1970-01-01

An endonuclease purified from Micrococcus luteus makes single-strand breaks in ultraviolet (UV)-irradiated, native deoxyribonucleic acid (DNA). The purified endonuclease is able to reactivate UV-inactivated transforming DNA of Haemophilus influenzae, especially when the DNA is assayed on a UV-sensitive mutant of H. influenzae. After extensive endonuclease action, there is a loss of transforming DNA when assayed on both UV-sensitive and -resistant cells. The endonuclease does not affect unirradiated DNA. The results indicate that the endonuclease function is involved in the repair of biological damage resulting from UV irradiation and that the UV-sensitive mutant is deficient in this step. We interpret the data as indicating that the various steps in the repair of DNA must be well coordinated if repair is to be effective. PMID:4314478