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Sample records for maximum uv indices

  1. UV inactivation of pathogenic and indicator microorganisms

    International Nuclear Information System (INIS)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-01-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts

  2. UV inactivation of pathogenic and indicator microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-06-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.

  3. UV “Indices”—What Do They Indicate?

    Directory of Open Access Journals (Sweden)

    Hanns Moshammer

    2016-10-01

    Full Text Available Ultra-Violet (UV radiation covers the spectrum of wavelengths from 100 to 400 nm. The potency and biological activity for a variety of endpoints differ by wavelength. For monitoring and communication purposes, different UV action spectra have been developed. These spectra use different weighting functions. The action spectrum for erythemal dose is the most widely used one. This erythemal dose per time or dose-rate has been further simplified into a “UV index”. Following this example, in our review we use the term “index” or (plural “indices” in a more general description for all simplified single-value measures for any biologically effective UV dose, e.g., for human non-melanoma skin cancer and for previtamin D production rate. Ongoing discussion about the existence of an increased melanoma risk due to UV-A exposure underscores the uncertainties inherent in current weighting functions. Thus, we performed an online literature search to review the data basis for these indices, to understand their relevance for an individual, and to assess the applicability of the indices for a range of exposure scenarios. Even for natural (solar UV, the spectral composition varies spatially and temporally. Artificial UV sources and personal protection introduce further variation to the spectral composition. Many biological effects are proposed for UV radiation. Only few endpoints have been studied sufficiently to estimate a reliable index. Weighting functions for chronic effects and most importantly for cancer endpoints have been developed in animal models, and often for proxy endpoints only. Epidemiological studies on biological effects of UV radiation should not only depend on single-value weighted UV dose estimates (indexes but should strive for a more detailed description of the individual exposure. A better understanding of the adverse and beneficial effects of UV radiation by wavelength would also improve medical counseling and health

  4. MAXIMUM CORONAL MASS EJECTION SPEED AS AN INDICATOR OF SOLAR AND GEOMAGNETIC ACTIVITIES

    International Nuclear Information System (INIS)

    Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Gopalswamy, N.; Ozguc, A.; Rozelot, J. P.

    2011-01-01

    We investigate the relationship between the monthly averaged maximal speeds of coronal mass ejections (CMEs), international sunspot number (ISSN), and the geomagnetic Dst and Ap indices covering the 1996-2008 time interval (solar cycle 23). Our new findings are as follows. (1) There is a noteworthy relationship between monthly averaged maximum CME speeds and sunspot numbers, Ap and Dst indices. Various peculiarities in the monthly Dst index are correlated better with the fine structures in the CME speed profile than that in the ISSN data. (2) Unlike the sunspot numbers, the CME speed index does not exhibit a double peak maximum. Instead, the CME speed profile peaks during the declining phase of solar cycle 23. Similar to the Ap index, both CME speed and the Dst indices lag behind the sunspot numbers by several months. (3) The CME number shows a double peak similar to that seen in the sunspot numbers. The CME occurrence rate remained very high even near the minimum of the solar cycle 23, when both the sunspot number and the CME average maximum speed were reaching their minimum values. (4) A well-defined peak of the Ap index between 2002 May and 2004 August was co-temporal with the excess of the mid-latitude coronal holes during solar cycle 23. The above findings suggest that the CME speed index may be a useful indicator of both solar and geomagnetic activities. It may have advantages over the sunspot numbers, because it better reflects the intensity of Earth-directed solar eruptions.

  5. Development and Validation of a Stability-Indicating LC-UV Method ...

    African Journals Online (AJOL)

    Development and Validation of a Stability-Indicating LC-UV Method for Simultaneous Determination of Ketotifen and Cetirizine in Pharmaceutical Dosage Forms. ... 5 μm) using an isocratic mobile phase that consisted of acetonitrile and 10 mM disodium hydrogen phosphate buffer (pH 6.5) in a ratio of 45:55 % v/v at a flow ...

  6. Maximum Diameter and Number of Tumors as a New Prognostic Indicator of Colorectal Liver Metastases.

    Science.gov (United States)

    Yoshimoto, Toshiaki; Morine, Yuji; Imura, Satoru; Ikemoto, Tetsuya; Iwahashi, Syuichi; Saito, Y U; Yamada, Sinichiro; Ishikawa, Daichi; Teraoku, Hiroki; Yoshikawa, Masato; Higashijima, Jun; Takasu, Chie; Shimada, Mitsuo

    2017-01-01

    Surgical resection is currently considered the only potentially curative option as a treatment strategy of colorectal liver metastases (CRLM). However, the criteria for selection of resectable CRLM are not clear. The aim of this study was to confirm a new prognostic indicator of CRLM after hepatic resection. One hundred thirty nine patients who underwent initial surgical resection from 1994 to 2015 were investigated retrospectively. Prognostic factors of overall survival including the product of maximum diameter and number of metastases (MDN) were analyzed. Primary tumor differentiation, vessel invasion, lymph node (LN) metastasis, non-optimally resectable metastases, H score, grade of liver metastases, resection with non-curative intent and MDN were found to be prognostic factors of overall survival (OS). In multivariate analyses of clinicopathological features associated with OS, MDN and non-curative intent were independent prognostic factors. Patients with MDN ≥30 had shown significantly poorer prognosis than patients with MDN <30 in OS and relapse-free survival (RFS). MDN ≥30 is an independent prognostic factor of survival in patients with CRLM and optimal surgical criterion of hepatectomy for CRLM. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  7. Artemisia pollen-indicated steppe distribution in southern China during the Last Glacial Maximum

    Directory of Open Access Journals (Sweden)

    Liu Hongyan

    2013-07-01

    Full Text Available The Last Glacial Maximum (LGM was the coldest period during the previous 20,000 years. There have been different points of views on steppe distribution during the LGM period in southern China, partly due to the different interpretations of Artemisia occurrences. To make a reliable interpretation of the pollen fossil Artemisia, the modern distribution of Artemisia species and the relationship of pollen with climate and vegetation over a large spatial scale in China was thoroughly analyzed. Information about Artemisia species and pollen distributions used in this paper were collected from published works completed by other researchers as well as ourselves. The southern limit of steppe vegetation during the LGM period was interpreted from the published contour map of Artemisia pollen percentages during the LGM. Artemisia species in China are mostly distributed either in the horizontally distributed steppe regions or in the vertically distributed desert-steppe in the desert region, which indicates a cold and dry climate. The steppe is a distribution center of Artemisia pollen. Fractions of Artemisia in surface pollen assemblages are lower in both the desert and the temperate forest. Neither high Artemisia species cover nor high percentages of Artemisia pollen were found in the coast areas of China. Twenty-five percent of Artemisia pollen in sediments might indicate a local occurrence of steppe vegetation. Percentages of Artemisia pollen in the subtropical and tropical forest are less than 10%. A close relationship between Artemisia pollen and temperate steppe in China is demonstrated. The southern edge of the steppe vegetation during the LGM might be along the middle reach of the Yangtze River. Our results support the hypothesis that the isolated high fraction of Artemisia pollen along the northern edge of the South China Sea was transported from a large source area.

  8. Determining Changes in Electromyography Indices when Measuring Maximum Acceptable Weight of Lift in Iranian Male Students.

    Science.gov (United States)

    Salehi Sahl Abadi, A; Mazloumi, A; Nasl Saraji, G; Zeraati, H; Hadian, M R; Jafari, A H

    2018-03-01

    In spite of the increasing degree of automation in industry, manual material handling (MMH) is still performed in many occupational settings. The aim of the current study was to determine the maximum acceptable weight of lift using psychophysical and electromyography indices. This experimental study was conducted among 15 male students recruited from Tehran University of Medical Sciences. Each participant performed 18 different lifting tasks which involved three lifting frequencies, three lifting heights and two box sizes. Each set of experiments was conducted during the 20 min work period using free-style lifting technique and subjective as well as objective assessment methodologies. SPSS version 18 software was used for descriptive and analytical analyses by Friedman, Wilcoxon and Spearman correlation techniques. The results demonstrated that muscle activity increased with increasing frequency, height of lift and box size (P<0.05). Meanwhile, MAWLs obtained in this study are lower than those in Snook table (P<0.05). In this study, the level of muscle activity in percent MVC in relation to the erector spine muscles in L3 and T9 regions as well as left and right abdominal external oblique muscles were at 38.89%, 27.78%, 11.11% and 5.55% in terms of muscle activity is more than 70% MVC, respectively. The results of Wilcoxon test revealed that for both small and large boxes under all conditions, significant differences were detected between the beginning and end of the test values for MPF of erector spine in L3 and T9 regions, and left and right abdominal external oblique muscles (P<0.05). The results of Spearman correlation test showed that there was a significant relation between the MAWL, RMS and MPF of the muscles in all test conditions (P<0.05). Based on the results of this study, it was concluded if muscle activity is more than 70% of MVC, the values of Snook tables should be revisited. Furthermore, the biomechanical perspective should receive special attention

  9. Allometries of Maximum Growth Rate versus Body Mass at Maximum Growth Indicate That Non-Avian Dinosaurs Had Growth Rates Typical of Fast Growing Ectothermic Sauropsids

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2014-01-01

    We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case’s study (1978), which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles) to 20 (fishes) times (in comparison to mammals) or even 45 (reptiles) to 100 (fishes) times (in comparison to birds) lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule out either

  10. Allometries of maximum growth rate versus body mass at maximum growth indicate that non-avian dinosaurs had growth rates typical of fast growing ectothermic sauropsids.

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2014-01-01

    We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case's study (1978), which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles) to 20 (fishes) times (in comparison to mammals) or even 45 (reptiles) to 100 (fishes) times (in comparison to birds) lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule out either of

  11. Allometries of maximum growth rate versus body mass at maximum growth indicate that non-avian dinosaurs had growth rates typical of fast growing ectothermic sauropsids.

    Directory of Open Access Journals (Sweden)

    Jan Werner

    Full Text Available We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes strongly differed from Case's study (1978, which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles to 20 (fishes times (in comparison to mammals or even 45 (reptiles to 100 (fishes times (in comparison to birds lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule

  12. Correlation of patient maximum skin doses in cardiac procedures with various dose indicators

    International Nuclear Information System (INIS)

    Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.; Werduch, A.; Religa, W.

    2008-01-01

    In most countries of European Union, legislation requires the determination of the total skin dose received by patients during interventional procedures in order to prevent deterministic damages. Various dose indicators like dose-area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used for patient dosimetry purposes in clinical practice. This study aimed at relating those dose indicators with doses ascribed to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). The study was performed in two different facilities for two most common cardiac procedures coronary angiography (CA) and percutaneous coronary interventions (PCI). For CA procedures, the registered values of fluoroscopy time, total DAP and MSD were in the range (0.7-27.3) min, (16-317) Gy cm 2 and (43-1507) mGy, respectively, and for interventions, accordingly (2.1-43.6) min, (17-425) Gy cm 2 , (71-1555) mGy. Moreover, for CA procedures, CD and EFD were in the ranges (295-4689) mGy and (121-1768) mGy and for PCI (267-6524) mGy and (68-2279) mGy, respectively. No general and satisfactory correlation was found for safe estimation of MSD. However, results show that the best dose indicator which might serve for rough, preliminary estimation is DAP value. In the study, the appropriate trigger levels were proposed for both facilities. (authors)

  13. Stability indicating HPLC-UV method for detection of curcumin in Curcuma longa extract and emulsion formulation.

    Science.gov (United States)

    Syed, Haroon Khalid; Liew, Kai Bin; Loh, Gabriel Onn Kit; Peh, Kok Khiang

    2015-03-01

    A stability-indicating HPLC-UV method for the determination of curcumin in Curcuma longa extract and emulsion was developed. The system suitability parameters, theoretical plates (N), tailing factor (T), capacity factor (K'), height equivalent of a theoretical plate (H) and resolution (Rs) were calculated. Stress degradation studies (acid, base, oxidation, heat and UV light) of curcumin were performed in emulsion. It was found that N>6500, Tcurcumin were ⩽0.87% and ⩽2.0%, while the inter-day precision and accuracy values were ⩽2.1% and ⩽-1.92. Curcumin degraded in emulsion under acid, alkali and UV light. In conclusion, the stability-indicating method could be employed to determine curcumin in bulk and emulsions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Comparing fishers' and scientific estimates of size at maturity and maximum body size as indicators for overfishing.

    Science.gov (United States)

    Mclean, Elizabeth L; Forrester, Graham E

    2018-04-01

    We tested whether fishers' local ecological knowledge (LEK) of two fish life-history parameters, size at maturity (SAM) at maximum body size (MS), was comparable to scientific estimates (SEK) of the same parameters, and whether LEK influenced fishers' perceptions of sustainability. Local ecological knowledge was documented for 82 fishers from a small-scale fishery in Samaná Bay, Dominican Republic, whereas SEK was compiled from the scientific literature. Size at maturity estimates derived from LEK and SEK overlapped for most of the 15 commonly harvested species (10 of 15). In contrast, fishers' maximum size estimates were usually lower than (eight species), or overlapped with (five species) scientific estimates. Fishers' size-based estimates of catch composition indicate greater potential for overfishing than estimates based on SEK. Fishers' estimates of size at capture relative to size at maturity suggest routine inclusion of juveniles in the catch (9 of 15 species), and fishers' estimates suggest that harvested fish are substantially smaller than maximum body size for most species (11 of 15 species). Scientific estimates also suggest that harvested fish are generally smaller than maximum body size (13 of 15), but suggest that the catch is dominated by adults for most species (9 of 15 species), and that juveniles are present in the catch for fewer species (6 of 15). Most Samaná fishers characterized the current state of their fishery as poor (73%) and as having changed for the worse over the past 20 yr (60%). Fishers stated that concern about overfishing, catching small fish, and catching immature fish contributed to these perceptions, indicating a possible influence of catch-size composition on their perceptions. Future work should test this link more explicitly because we found no evidence that the minority of fishers with more positive perceptions of their fishery reported systematically different estimates of catch-size composition than those with the more

  15. Development and Validation of a Stability-Indicating LC-UV Method ...

    African Journals Online (AJOL)

    Keywords: Ketotifen, Cetirizine, Stability indicating method, Stressed conditions, Validation. Tropical ... in biological fluids [13] are also reported. Stability indicating HPLC method is reported for ketotifen where drug is ..... paracetamol, cetirizine.

  16. UV-screening Organic Matter (CDOM and MAA) as indicators for monitoring changes of the polar marine ecosystem

    Science.gov (United States)

    PARK, M. O.; Kang, S. H.; Ha, S. Y.

    2014-12-01

    At Kongsfjorden bay, DOC, CDOM, FDOM, composition of phytoplankton and MAAs were measured from seawater. The relationship between CDOM, DOC vs Chl a was also investigated. DOC of seawater in 2010 and 2011 was increased 68% and 34% respectively in average compared to DOC in 2009. CDOM was in the range of acdom(375): 0.1855 m-1 ~ 0.0965 m-1, and it showed clear decreasing gradient form inside bay to offshore. CDOM vs DOC and Chl a was inversely related in the study area. Biomass of phytoplankton during 2009~2011 was 0.43~ 0.76 mg/m3 and little change was observed, but the composition and dominant classes have changed. Phaeocystis sp. was rare and diatom and cryptophyte were dominant in the center of bay and coastal area, respectively. 5 different MAAs, shinorine, palythine, mycosporine-glycine, porphyra-334, asterine-330 are identified and separated from Arctic phytoplanktons by HPLC and an unknown MAA was identified from Phaeocystis pouchetti. The spatial distribution pattern of MAAs in the study area was similar with the distribution of Phaeocystis sp. in 2009. The concentration of MAA in 2011 was decreased upto 50% with maximum concentration and seems to related with very low abundance of Phaeocystis sp. in the bay. The results from UV B exposure experiment with Phaeocystis pouchetti. and Porosira glacialis revealed clear discrepancy in the response to carbon uptake rate and photo-inhibition, and also the organic matter from these phytoplankton showed a different photo reactivity. Porosira glacialis, larger than Phaeocystis pouchetti. was more resistant to harmful UV B effect and result of carbon uptake rate using 13C support this tendency. In case Phaeocystis pouchetti becomes the dominant species, it is likely CDOM will be easily degraded and the UV screening effect of seawater will be reduced. acdom(375) 0.14m-1in spring in the arctic was higher than 0.11m-1 in the antarctic at monitoring station. These 3 year monitoring in the arctic Kongsfjorden showed a

  17. An Analysis of Cumulative Risks Indicated by Biomonitoring Data of Six Phthalates Using the Maximum Cumulative Ratio

    Science.gov (United States)

    The Maximum Cumulative Ratio (MCR) quantifies the degree to which a single component of a chemical mixture drives the cumulative risk of a receptor.1 This study used the MCR, the Hazard Index (HI) and Hazard Quotient (HQ) to evaluate co-exposures to six phthalates using biomonito...

  18. The effect of UV treatment of autogenic blood on some chemical indices in sheep with Corynebacterial infection

    International Nuclear Information System (INIS)

    Filipov, Zh.; Borisov, I.; Bodurov, N.

    1985-01-01

    Following the transfusion of both untreated and treated blood the amount of blood sugar rose reaching higher levels in the case UV-treated blood. There were changes in the total protein and the protein fractions induced by the Corynebacterial infection, however, the initial levels were more rapidly restored in the case of transfusing UV-trated blood. With autohemotransfusion the values of glutamate oxalacetate transaminase in all animals dropped. The change was more rapidly and more strongly expressed with the transfusion of UV-treated blood

  19. Stability-indicating HPLC-DAD/UV-ESI/MS impurity profiling of the anti-malarial drug lumefantrine.

    Science.gov (United States)

    Verbeken, Mathieu; Suleman, Sultan; Baert, Bram; Vangheluwe, Elien; Van Dorpe, Sylvia; Burvenich, Christian; Duchateau, Luc; Jansen, Frans H; De Spiegeleer, Bart

    2011-02-28

    Lumefantrine (benflumetol) is a fluorene derivative belonging to the aryl amino alcohol class of anti-malarial drugs and is commercially available in fixed combination products with β-artemether. Impurity characterization of such drugs, which are widely consumed in tropical countries for malaria control programmes, is of paramount importance. However, until now, no exhaustive impurity profile of lumefantrine has been established, encompassing process-related and degradation impurities in active pharmaceutical ingredients (APIs) and finished pharmaceutical products (FPPs). Using HPLC-DAD/UV-ESI/ion trap/MS, a comprehensive impurity profile was established based upon analysis of market samples as well as stress, accelerated and long-term stability results. In-silico toxicological predictions for these lumefantrine related impurities were made using Toxtree® and Derek®. Several new impurities are identified, of which the desbenzylketo derivative (DBK) is proposed as a new specified degradant. DBK and the remaining unspecified lumefantrine related impurities are predicted, using Toxtree® and Derek®, to have a toxicity risk comparable to the toxicity risk of the API lumefantrine itself. From unstressed, stressed and accelerated stability samples of lumefantrine API and FPPs, nine compounds were detected and characterized to be lumefantrine related impurities. One new lumefantrine related compound, DBK, was identified and characterized as a specified degradation impurity of lumefantrine in real market samples (FPPs). The in-silico toxicological investigation (Toxtree® and Derek®) indicated overall a toxicity risk for lumefantrine related impurities comparable to that of the API lumefantrine itself.

  20. Maximum home blood pressure is a useful indicator of diabetic nephropathy in patients with type 2 diabetes mellitus: KAMOGAWA-HBP study.

    Science.gov (United States)

    Oyabu, Chikako; Ushigome, Emi; Matsumoto, Shinobu; Tanaka, Toru; Hasegawa, Goji; Nakamura, Naoto; Ohnishi, Masayoshi; Tsunoda, Sei; Ushigome, Hidetaka; Yokota, Isao; Tanaka, Muhei; Asano, Mai; Yamazaki, Masahiro; Fukui, Michiaki

    2017-11-01

    Maximum home systolic blood pressure has been shown to predict target organ damage. We aimed to clarify the association between maximum home systolic blood pressure and urine albumin to creatinine ratio, an indicator of early-phase diabetic nephropathy in patients with type 2 diabetes. In 1040 patients, we assessed the relationship of mean or maximum home systolic blood pressure and urine albumin to creatinine ratio, and compared the area under the receiver operating characteristic curve of mean or maximum home systolic blood pressure for diabetic nephropathy (urine albumin to creatinine ratio ⩾30 mg/g Cr). Multivariate linear regression analyses indicated that mean morning systolic blood pressure ( β = 0.010, p blood pressure ( β = 0.008, p blood pressure was 0.667 (0.634-0.700; p blood pressure, as well as mean home systolic blood pressure, was significantly associated with diabetic nephropathy in patients with type 2 diabetes.

  1. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots. 13 references

  2. Application of surrogates, indicators, and high-resolution mass spectrometry to evaluate the efficacy of UV processes for attenuation of emerging contaminants in water.

    Science.gov (United States)

    Merel, Sylvain; Anumol, Tarun; Park, Minkyu; Snyder, Shane A

    2015-01-23

    In response to water scarcity, strategies relying on multiple processes to turn wastewater effluent into potable water are being increasingly considered by many cities. In such context, the occurrence of contaminants as well as their fate during treatment processes is a major concern. Three analytical approaches where used to characterize the efficacy of UV and UV/H2O2 processes on a secondary wastewater effluent. The first analytical approach assessed bulk organic parameters or surrogates before and after treatment, while the second analytical approach measured the removal of specific indicator compounds. Sixteen trace organic contaminants were selected due to their relative high concentration and detection frequency over eight monitoring campaigns. While their removal rate ranges from approximately 10 to >90%, some of these compounds can be used to gauge process efficacy (or failure). The third analytical approach assessed the fate of unknown contaminants through high-resolution time-of-flight (TOF) mass spectrometry with advanced data processing and demonstrated the occurrence of several thousand organic compounds in the water. A heat map clearly evidenced compounds as recalcitrant or transformed by the UV processes applied. In addition, those chemicals with similar fate were grouped together into clusters to identify new indicator compounds. In this manuscript, each approach is evaluated with advantages and disadvantages compared. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Development, validation and comparison of two stability-indicating RP-LC methods using charged aerosol and UV detectors for analysis of lisdexamfetamine dimesylate in capsules

    Directory of Open Access Journals (Sweden)

    Graciela Carlos

    2016-11-01

    Full Text Available Two new stability-indicating liquid chromatographic methods using two detectors, an ultraviolet (UV and a charged aerosol detector (CAD simultaneously connected in series were validated for the assessment of lisdexamfetamine dimesylate (LDX in capsule. The method was optimized and the influence of individual parameters on UV and CAD response and sensitivity was studied. Chromatography was performed on a Zorbax CN column (250 mm × 4.6 mm, 5 μm in an isocratic elution mode, using acetonitrile and 20 mM ammonium formate at pH 4.0 (50:50, v/v as mobile phase and UV detection at 207 nm. The developed method was validated according to ICH guidelines and the parameters’ specificity, limit of detection, limit of quantitation, linearity, accuracy, precision and robustness were evaluated. CAD is designated to be a non-linear detector in a wide dynamic range, however, the method was linear over the concentration range of 70–130 μg mL−1 in both detectors. The method was precise and accurate. Robustness study was performed by a Plackett–Burman design, delivering results within the acceptable range. Neither the excipients nor the degradation products showed interference in the method after studies of specificity as well as under stress conditions. The results of the LC-UV and LC-CAD methods were statistically compared through ANOVA and showed no significant difference (p > 0.05. Both proposed methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate quality control tool for routine analysis of LDX in capsule.

  4. Optical ages indicate the southwestern margin of the Green Bay Lobe in Wisconsin, USA, was at its maximum extent until about 18,500 years ago

    Science.gov (United States)

    Attig, J.W.; Hanson, P.R.; Rawling, J.E.; Young, A.R.; Carson, E.C.

    2011-01-01

    Samples for optical dating were collected to estimate the time of sediment deposition in small ice-marginal lakes in the Baraboo Hills of Wisconsin. These lakes formed high in the Baraboo Hills when drainage was blocked by the Green Bay Lobe when it was at or very near its maximum extent. Therefore, these optical ages provide control for the timing of the thinning and recession of the Green Bay Lobe from its maximum position. Sediment that accumulated in four small ice-marginal lakes was sampled and dated. Difficulties with field sampling and estimating dose rates made the interpretation of optical ages derived from samples from two of the lake basins problematic. Samples from the other two lake basins-South Bluff and Feltz basins-responded well during laboratory analysis and showed reasonably good agreement between the multiple ages produced at each site. These ages averaged 18.2. ka (n= 6) and 18.6. ka (n= 6), respectively. The optical ages from these two lake basins where we could carefully select sediment samples provide firm evidence that the Green Bay Lobe stood at or very near its maximum extent until about 18.5. ka.The persistence of ice-marginal lakes in these basins high in the Baraboo Hills indicates that the ice of the Green Bay Lobe had not experienced significant thinning near its margin prior to about 18.5. ka. These ages are the first to directly constrain the timing of the maximum extent of the Green Bay Lobe and the onset of deglaciation in the area for which the Wisconsin Glaciation was named. ?? 2011 Elsevier B.V.

  5. Impacts of climate change on the trends of extreme rainfall indices and values of maximum precipitation at Olimpiyat Station, Istanbul, Turkey

    Science.gov (United States)

    Nigussie, Tewodros Assefa; Altunkaynak, Abdusselam

    2018-03-01

    In this study, extreme rainfall indices of Olimpiyat Station were determined from reference period (1971-2000) and future period (2070-2099) daily rainfall data projected using the HadGEM2-ES and GFDL-ESM2M global circulation models (GCMs) and downscaled by the RegCM4.3.4 regional model under the Representative Concentration Pathway RCP4.5 and RCP8.5 scenarios. The Mann-Kendall (MK) trend statistics was used to detect trends in the indices of each group, and the nonparametric Wilcoxon signed ranks test was employed to identify the presence of differences among the values of the rainfall indices of the three groups. Moreover, the peaks-over-threshold (POT) method was used to undertake frequency analysis and estimate the maximum 24-h rainfall values of various return periods. The results of the M-K-based trend analyses showed that there are insignificant increasing trends in most of the extreme rainfall indices. However, based on the Wilcoxon signed ranks test, the values of the extreme rainfall indices determined for the future period, particularly under RCP8.5, were found to be significantly different from the corresponding values determined for the reference period. The maximum 24-h rainfall amounts of the 50-year return period of the future period under RCP4.5 of the HadGEM2-ES and GFDL-ESM2M GCMs were found to be larger (by 5.85%) than the corresponding value of the reference period by 5.85 and 21.43%, respectively. The results also showed that the maximum 24-h rainfall amount under RCP8.5 of both the HadGEM2-ES and GFDL-ESM2M GCMs was found to be greater (34.33 and 12.18%, respectively, for the 50-year return period) than the reference period values. This may increase the risk of flooding in Ayamama Watershed, and thus, studying the effects of the predicted amount of rainfall under the RCP8.5 scenario on the flooding risk of Ayamama Watershed and devising management strategies are recommended to enhance the design and implementation of adaptation measures.

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

    Science.gov (United States)

    2015-03-26

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

  7. No indications of an enhanced UV-light-induced unscheduled DNA synthesis in splenocytes of mice following a low-dose irradiation in vivo or in vitro

    International Nuclear Information System (INIS)

    Wojcik, A.; Seemayer, C.A.; Mueller, W.U.; Streffer, C.

    1995-01-01

    One of the open questions regarding the adaptive response to ionizing radiation is whether it can be induced in G 0 lymphocytes. In the majority of experiments in which an adaptive response in G 0 lymphocytes was observed, the adapting dose was applied in vivo. In order to investigate whether there is some in vivo component of adaptive response, mouse splenocytes of the C57BL/6 strain were irradiated with 0.1 Gy x-rays either in vivo or in vitro, and their UV-light-induced unscheduled DNA synthesis (UDS) levels were determined autoradiographically. An augmented UV-light-induced UDS following an adapting dose applied in vivo has previously been described by several authors in splenocytes of C57BL/6 mice, indicating that the adapting dose enhanced the DNA repair capacity of lymphocytes. In the present investigation, however, no evidence of an adaptive response could be seen regardless of whether the adapting dose was given in vivo or in vitro. Those results present a further indication for the fact that the adaptive response to ionizing radiation is not always inducible, even in lymphocytes of an inbred mouse strain in which its existence has been reported before. (orig.)

  8. UV-Vis-IR spectral complex refractive indices and optical properties of brown carbon aerosol from biomass burning

    Science.gov (United States)

    Sumlin, Benjamin J.; Heinson, Yuli W.; Shetty, Nishit; Pandey, Apoorva; Pattison, Robert S.; Baker, Stephen; Hao, Wei Min; Chakrabarty, Rajan K.

    2018-02-01

    Constraining the complex refractive indices, optical properties and size of brown carbon (BrC) aerosols is a vital endeavor for improving climate models and satellite retrieval algorithms. Smoldering wildfires are the largest source of primary BrC, and fuel parameters such as moisture content, source depth, geographic origin, and fuel packing density could influence the properties of the emitted aerosol. We measured in situ spectral (375-1047 nm) optical properties of BrC aerosols emitted from smoldering combustion of Boreal and Indonesian peatlands across a range of these fuel parameters. Inverse Lorenz-Mie algorithms used these optical measurements along with simultaneously measured particle size distributions to retrieve the aerosol complex refractive indices (m = n + iκ). Our results show that the real part n is constrained between 1.5 and 1.7 with no obvious functionality in wavelength (λ), moisture content, source depth, or geographic origin. With increasing λ from 375 to 532 nm, κ decreased from 0.014 to 0.003, with corresponding increase in single scattering albedo (SSA) from 0.93 to 0.99. The spectral variability of κ follows the Kramers-Kronig dispersion relation for a damped harmonic oscillator. For λ ≥ 532 nm, both κ and SSA showed no spectral dependency. We discuss differences between this study and previous work. The imaginary part κ was sensitive to changes in FPD, and we hypothesize mechanisms that might help explain this observation.

  9. Inter-comparison of the solar UVB, UVA and global radiation clearness and UV indices for Beer Sheva and Neve Zohar (Dead Sea), Israel

    International Nuclear Information System (INIS)

    Kudish, A.I.; Lyubansky, V.; Evseev, E.G.; Ianetz, A.

    2005-01-01

    An inter-comparison of the clearness indices for the solar UVB, UVA and global radiation for Beer Sheva and Neve Zohar (Dead Sea) are presented utilizing radiation data measured from January 1995 through December 2001 for which there is a one-to-one correspondence between the measurements, viz., any day for which a hourly value for one of the sites was missing is rejected and not included in the analysis for that particular radiation type. Beer Sheva is located ca. 65 km to the west and is approximately 700 m above Neve Zohar, which is located on the western shore of the Dead Sea. The Dead Sea is the lowest terrestrial point on the earth, approximately 400 m below mean sea level. The relative magnitudes of the global, UVB and UVA radiation intensities at the two sites can be attributed to the enhanced scattering at the Dead Sea due to the longer optical path length the solar radiation must traverse at the Dead Sea. The degree of attenuation due to scattering phenomena is inversely proportional to the wavelength raised to some power and, consequently, it is greatest for UVB and very small for global radiation. The UVB and UVA solar constants were determined from the extraterrestrial radiation values tabulated by Froehlich and Wehrli [Spectral distribution of solar irradiance from 25000 nm to 250nm, in: M. Iqbal, An introduction to solar radiation, Academic Press, New York, 1981, Appendix C, pp. 380-381]. The clearness indices for global and UVA radiation were of similar magnitude, whereas those for UVB radiation were of two orders of magnitude smaller. In addition, the monthly average hourly UV Index at both sites has also been determined and an inter-comparison of the values has been performed for all available hourly values from January 1995 through August 2002 for both sites. It is observed that the monthly average hourly UV Index values at the Dead Sea are never in the extreme range

  10. UV-indeks og dets betydning

    DEFF Research Database (Denmark)

    Wulf, Hans Christian; Eriksen, Paul

    2010-01-01

    The published UV index refers to the expected UV intensity at mid day, when the solar elevation is at its maximum. In Scandinavia, the maximum UV index is seven around midsummer. When the UV index is three, the erythema-weighted dose will be three Standard Erythema Dose (SED) in the hour with max...... a sunburn already when the UV index is higher than two....

  11. Prediction of daily UV-A from daily global solar irradiance using the Ktuv and Kt clearness index; Prediccion de valores diarios de radiacion solar UV-A (295-385 nm) utilizando los indices de transparencia K{sub t}uv y K{sub t} y tecnicas de resdes neuronales artificiales

    Energy Technology Data Exchange (ETDEWEB)

    Barbero, F. J.; Lopez, G.; Batlles, F. J.

    2004-07-01

    In this work we compare two methodologies in order to estimate daily UV-A from daily global solar irradiance measurements. The first one is based on standard statistical procedures for relating the daily clearness indices Ktuv and Kt and the relative air mass, whereas the second methodology is based on the novel techniques of artificial neuronal networks. In both cases, we employed data recorded at the radiometric station located at the University of Almeria between 1993 and 1996. Both models are checked against data for years not previously used. (Author)

  12. Vegetation change and terrestrial carbon storage in eastern Asia during the Last Glacial Maximum as indicated by a new pollen record from central Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Liew, P.M.; Kuo, C.M.; Huang, S.Y.; Tseng, M.H. [Geological Department, National Taiwan Univ. 245, Chou-shan Rd., Taipei (Taiwan, Province of China)

    1998-05-01

    Last Glacial Maximum (LGM) carbon storage in eastern Asia is a key issue for understanding the sinks and sources of paleocarbon. Palynological data with good time constraint for the LGM in a peat bog from a site at 650 m above mean sea level in central Taiwan, together with data from low-lying deltaic and basin deposits of Taiwan and South China, increase our understanding about vegetational evolution and possible terrestrial carbon storage in this area and probably eastern Asia. Contrasting to today`s Machilus-Castanopsis forest zone around the peat bog, the vegetation before the LGM was dominated by Alnus, a relatively xerophytic element in Taiwan. An increase in herbs and decrease in spores during the LGM is recognized when compared with Holocene and modern assemblages. A less humid interval dominated by herbs (>50%) occurred between 21 and 15.8 ka. Basin deposits in northern Taiwan and deltaic deposits in central Taiwan show that during the LGM Artemisia, Umbelliferae and Gramineae were the main components contrasting with the Pinus or Cyclobalanopsis-dominant assemblages in the rest of the last glacial. Thus, less humid conditions lasted about 5000 to 6000 years in the LGM even on this very humid island. This may also be true in eastern Asia where a large area of the widely exposed continental shelf may have been occupied by grasslands and the uplands of South China were occupied by less dense coniferous or temperate forests during the LGM in contrast to the modern subtropical forest. This scenario improves our understanding of the terrestrial paleocarbon storage

  13. Vegetation change and terrestrial carbon storage in eastern Asia during the Last Glacial Maximum as indicated by a new pollen record from central Taiwan

    Science.gov (United States)

    Liew, P. M.; Kuo, C. M.; Huang, S. Y.; Tseng, M. H.

    1998-05-01

    Last Glacial Maximum (LGM) carbon storage in eastern Asia is a key issue for understanding the sinks and sources of paleocarbon. Palynological data with good time constraint for the LGM in a peat bog from a site at 650 m above mean sea level in central Taiwan, together with data from low-lying deltaic and basin deposits of Taiwan and South China, increase our understanding about vegetational evolution and possible terrestrial carbon storage in this area and probably eastern Asia. Contrasting to today's Machilus-Castanopsis forest zone around the peat bog, the vegetation before the LGM was dominated by Alnus, a relatively xerophytic element in Taiwan. An increase in herbs and decrease in spores during the LGM is recognized when compared with Holocene and modern assemblages. A less humid interval dominated by herbs (>50%) occurred between 21 and 15.8 ka. Basin deposits in northern Taiwan and deltaic deposits in central Taiwan show that during the LGM Artemisia, Umbelliferae and Gramineae were the main components contrasting with the Pinus or Cyclobalanopsis-dominant assemblages in the rest of the last glacial. Thus, less humid conditions lasted about 5000 to 6000 years in the LGM even on this very humid island. This may also be true in eastern Asia where a large area of the widely exposed continental shelf may have been occupied by grasslands and the uplands of South China were occupied by less dense coniferous or temperate forests during the LGM in contrast to the modern subtropical forest. This scenario improves our understanding of the terrestrial paleocarbon storage.

  14. UV filters bioaccumulation in fish from Iberian river basins

    Energy Technology Data Exchange (ETDEWEB)

    Gago-Ferrero, Pablo [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens (Greece); Díaz-Cruz, M. Silvia, E-mail: sdcqam@cid.csic.es [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Barceló, Damià [Dept. of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, E-08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, C/ Emili Grahit, 101 Edifici H2O, E-17003 Girona (Spain)

    2015-06-15

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/g d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/g d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04–0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. - Highlights: • First evidence of UV filters in fish from Iberian rivers • Biota-sediment accumulation factors (BSAFs) were always below 1. • Predator species presented higher UV-F concentrations suggesting trophic magnification.

  15. UV filters bioaccumulation in fish from Iberian river basins

    International Nuclear Information System (INIS)

    Gago-Ferrero, Pablo; Díaz-Cruz, M. Silvia; Barceló, Damià

    2015-01-01

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/g d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/g d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04–0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. - Highlights: • First evidence of UV filters in fish from Iberian rivers • Biota-sediment accumulation factors (BSAFs) were always below 1. • Predator species presented higher UV-F concentrations suggesting trophic magnification

  16. Isolation and characterization of a degradation product in leflunomide and a validated selective stability-indicating HPLC–UV method for their quantification

    Directory of Open Access Journals (Sweden)

    Balraj Saini

    2015-06-01

    Full Text Available Leflunomide (LLM is subjected to forced degradation under conditions of hydrolysis, oxidation, dry heat, and photolysis as recommended by International Conference on Harmonization guideline Q1A(R2. In total, four degradation products (I–IV were formed under different conditions. Products I, II and IV were formed in alkaline hydrolytic, acidic hydrolytic and alkaline photolytic conditions. LLM and all degradation products were optimally resolved by gradient elution over a C18 column. The major degradation product (IV formed in hydrolytic alkaline conditions was isolated through column chromatography. Based on its 1H NMR, IR and mass spectral data, it was characterized as a British Pharmacopoeial impurity B. The HPLC method was found to be linear, accurate, precise, sensitive, specific, rugged and robust for quantification of LLM as well as product IV. Finally, the method was applied to stability testing of the commercially available LLM tablets. Keywords: Leflunomide, Characterization, Forced degradation, Degradation product, HPLC–UV

  17. Development and validation of a stability-indicating HPLC-UV method for the determination of triamcinolone acetonide and its degradation products in an ointment formulation

    NARCIS (Netherlands)

    van Heugten, A J P; Boer, W.; de Vries, W S; Markesteijn, C M A; Vromans, H

    2018-01-01

    A stability indicating high performance liquid chromatography method has been developed for the determination of triamcinolone acetonide (TCA) and its main degradation products in ointment formulations. The method, based on extensive stress testing using metal salts, azobisisobutyronitrile, acid,

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

    Science.gov (United States)

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

    2015-10-01

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

  19. Establishment of inherent stability of pramipexole and development of validated stability indicating LC–UV and LC–MS method

    Directory of Open Access Journals (Sweden)

    Shubhangi M. Pawar

    2013-04-01

    Full Text Available Pramipexole belongs to a class of nonergot dopamine agonist recently approved for the treatment of early and advanced Parkinson's disease. A validated specific stability indicating reversed-phase liquid chromatographic method has been developed for the quantitative determination of pramipexole in bulk as well as in pharmaceutical dosage forms in the presence of degradation products. Forced degradation studies were performed by exposition of drug to hydrolytic (acidic and basic, oxidative and photolytic stress conditions, as defined under ICH guideline Q1A (R2. Significant degradation was observed under hydrolytic, oxidative and photolytic conditions and the degradation products formed were identified by LC–MS. Keywords: Degradation products, Forced degradation/stress studies, Liquid chromatography mass spectrometry, Pramipexole, Reversed-phase liquid chromatography

  20. ESI-MSn and LC-ESI-MS studies to characterize forced degradation products of bosentan and a validated stability-indicating LC-UV method.

    Science.gov (United States)

    Bansal, Gulshan; Singh, Ranjit; Saini, Balraj; Bansal, Yogita

    2013-01-01

    The present study reports the characterization of forced degradation products of bosentan and a validated stability-indicating HPLC method for the stability testing of bosentan tablets. The forced degradation was carried out under the conditions of hydrolysis, oxidation, dry heat and photolysis. The drug was found unstable in acid, alkali and oxidative media whereas stable to the hydrolysis in water, to dry heat and to photolysis. In total, six degradation products were formed in all conditions which were resolved in a single run on a C-18 column with gradient elution using ammonium acetate buffer (pH 4.5, 5.0mM), methanol and acetonitrile. Structures of all the degradation products were characterized through +ESI-MS(n) and LC-ESI-MS spectral data of bosentan as well as LC-ESI-MS spectral data of the products. The products II-VI were characterized as 6-amino-[2,2']bipyrimidinyl-4,5-diol, 6-amino-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-ol, 2-[6-amino-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-yloxy]-ethanol, 4-tert-butyl-N-[6-(1-methoxyethoxy)-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-yl]-benzenesulfonamide and 4-tert-butyl-N-[6-hydroxy-5-(2-methoxyphenoxy)-[2,2']bipyrimidinyl-4-yl]-benzenesulfonamide, respectively. The peak of the product I was found to be due to two secondary degradation products which co-eluted and were characterized as β-hydroxyethyl p-tert-butylphenylsulfonate (Ia) and 2-[2-(2-hydroxyethoxy)-phenoxy]-ethanol (Ib). These products were formed due to hydrolysis of sulfonamide and alkylaryl ether and the diaryl ether linkages as well as dehydration of the primary alcohol group. The most probable degradation mechanisms were proposed. The HPLC method was found to be stability-indicating, linear (2-100 μg ml(-1)), accurate, precise, sensitive, specific, rugged and robust for quantitation of the drug. The method was applied to the stability testing of the commercially available bosentan tablets successfully. Copyright © 2012 Elsevier B.V. All

  1. A Validated Stability-indicating Reverse Phase HPLC Assay Method for the Determination of Memantine Hydrochloride Drug Substance with UV-Detection Using Precolumn Derivatization Technique

    Directory of Open Access Journals (Sweden)

    Bhavil Narola

    2010-01-01

    Full Text Available This present paper deals with the development and validation of a stability indicating high performance liquid chromatographic method for the quantitative determination of Memantine hydrochloride. Memantine hydrochloride was derivatized with 0.015 M 9-fluorenylmethyl chloroformate (FMOC and 0.5 M borate buffer solution by keeping it at room temperature for about 20 minutes and the chromatographic separation achieved by injecting 10 μL of the derivatized mixture into a Waters HPLC system with photodiode array detector using a kromasil C18 column (150 × 4.6 mm, 5 μ, The mobile phase consisting of 80% acetonitrile and 20% phosphate buffer solution and a flow rate of 2 milliliter/minute. The Memantine was eluted at approximately 7.5 minutes. The volume of FMOC used in derivatization, concentration of FMOC and derivatization time was optimized and used. Forced degradation studies were performed on bulk sample of Memantine hydrochloride using acid (5.0 Normal (N hydrochloric acid, base (1.0 N sodium hydroxide, oxidation (30% hydrogen peroxide, thermal (105 ° C, photolytic and humidity conditions. The developed LC method was validated with respect to specificity, precision (% RSD about 0.70%, linearity (linearity of range about 70-130 μg/mL, ruggedness (Overall % RSD about 0.35%, stability in analytical solution (Cumulative % RSD about 0.11% after 1450 min. and robustness.

  2. A Validated Stability-indicating Reverse Phase HPLC Assay Method for the Determination of Memantine Hydrochloride Drug Substance with UV-Detection Using Precolumn Derivatization Technique

    Directory of Open Access Journals (Sweden)

    Bhavil Narola

    2010-07-01

    Full Text Available This present paper deals with the development and validation of a stability indicating high performance liquid chromatographic method for the quantitative determination of Memantine hydrochloride. Memantine hydrochloride was derivatized with 0.015 M 9-fluorenylmethyl chloroformate (FMOC and 0.5 M borate buffer solution by keeping it at room temperature for about 20 minutes and the chromatographic separation achieved by injecting 10 µL of the derivatized mixture into a Waters HPLC system with photodiode array detector using a kromasil C18 column (150 × 4.6 mm, 5 µ. The mobile phase consisting of 80% acetonitrile and 20% phosphate buffer solution and a flow rate of 2 milliliter/minute. The Memantine was eluted at approximately 7.5 minutes. The volume of FMOC used in derivatization, concentration of FMOC and derivatization time was optimized and used. Forced degradation studies were performed on bulk sample of Memantine hydrochloride using acid (5.0 Normal (N hydrochloric acid, base (1.0 N sodium hydroxide, oxidation (30% hydrogen peroxide, thermal (105°C, photolytic and humidity conditions. The developed LC method was validated with respect to specificity, precision (% RSD about 0.70%, linearity (linearity of range about 70–130 µg/mL, ruggedness (Overall % RSD about 0.35%, stability in analytical solution (Cumulative % RSD about 0.11% after 1450 min. and robustness.

  3. UV filters bioaccumulation in fish from Iberian river basins.

    Science.gov (United States)

    Gago-Ferrero, Pablo; Díaz-Cruz, M Silvia; Barceló, Damià

    2015-06-15

    The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g dry weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7 ng/gd.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23 ng/gd.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04-0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. Copyright © 2015. Published by Elsevier B.V.

  4. Improving UV Resistance of High Performance Fibers

    Science.gov (United States)

    Hassanin, Ahmed

    % rutile TiO2 nanoparticles showed excellent protection of braid from PBO. Only 7.5% strength loss was observed. To optimize the degree of protection of the sheath loaded with UV blocker particles, computational models were developed to optimize the protective layer thickness/weight and the amount of UV particles that provide the maximum protection with lightest weight of the protective layer and minimum amount of UV particles. The simulated results were found to be higher that the experimental results due to the tendency of nanoparticles to be agglomerated in real experiments. The third approach to achieve a maximum protection with the minimum weight added is constructing a sleeve from SpectraRTM (Ultra High Molecular Weight Polyethylene (UHMWPE) high performance fiber), which is known to resist UV, woven fabric. Covering the braid from PBO fiber with Spectra RTM woven fabric provide hybrid structure with two compatible components that can share the load and thus maintain the high strength to weight ratio. Although the SpectraRTM fabric had maximum cover factor, 20 % of visible light and about 15 % of UV were able to penetrate the fabric. This transmittance of UV-VIS light negatively affected the protection performance of the SpectraRTM woven fabric layer. It is thought that SpectraRTM fabric be coated with a thin layer (mentioned earlier) containing UV blocker for additional protection while maintain strength contribution to the hybrid structure. To maximize the strength to weight ratio of the hybrid structure (with core from PBO braid and sheath from SpectraRTM woven fabric) an established finite element model was utilized. The theoretical results using the finite element theory indicated that by controlling the bending rigidity of the filling yarn of the SpectraRTM fabric, the extension at peak load of woven fabric in warp direction (loading direction) could be controlled to match the braid extension at peak load. The match in the extension at peak load of the two

  5. Ly α and UV Sizes of Green Pea Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huan; Wang, Junxian [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China (China); Malhotra, Sangeeta; Rhoads, James E.; Jiang, Tianxing [Arizona State University, School of Earth and Space Exploration (United States); Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218 (United States); Wofford, Aida, E-mail: huan.y@asu.edu [National Autonomous University of Mexico, Institute of Astronomy (Mexico)

    2017-03-20

    Green Peas are nearby analogs of high-redshift Ly α -emitting galaxies (LAEs). To probe their Ly α escape, we study the spatial profiles of Ly α and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope . We extract the spatial profiles of Ly α emission from their 2D COS spectra, and of the UV continuum from both 2D spectra and NUV images. The Ly α emission shows more extended spatial profiles than the UV continuum, in most Green Peas. The deconvolved full width at half maximum of the Ly α spatial profile is about 2–4 times that of the UV continuum, in most cases. Because Green Peas are analogs of high z LAEs, our results suggest that most high- z LAEs probably have larger Ly α sizes than UV sizes. We also compare the spatial profiles of Ly α photons at blueshifted and redshifted velocities in eight Green Peas with sufficient data quality, and find that the blue wing of the Ly α line has a larger spatial extent than the red wing in four Green Peas with comparatively weak blue Ly α line wings. We show that Green Peas and MUSE z = 3–6 LAEs have similar Ly α and UV continuum sizes, which probably suggests that starbursts in both low- z and high- z LAEs drive similar gas outflows illuminated by Ly α light. Five Lyman continuum (LyC) leakers in this sample have similar Ly α to UV continuum size ratios (∼1.4–4.3) to the other Green Peas, indicating that their LyC emissions escape through ionized holes in the interstellar medium.

  6. Maximum home systolic blood pressure is a useful indicator of arterial stiffness in patients with type 2 diabetes mellitus: post hoc analysis of a cross-sectional multicenter study.

    Science.gov (United States)

    Ushigome, Emi; Fukui, Michiaki; Hamaguchi, Masahide; Tanaka, Toru; Atsuta, Haruhiko; Mogami, Shin-ichi; Tsunoda, Sei; Yamazaki, Masahiro; Hasegawa, Goji; Nakamura, Naoto

    2014-09-01

    Maximum (max) home systolic blood pressure (HSBP) as well as mean HSBP or HSBP variability was reported to increase the predictive value of target organ damage. Yet, the association between max HSBP and target organ damage in patients with type 2 diabetes has never been reported. The aim of this study was to investigate the association between max HSBP and pulse wave velocity (PWV), a marker of arterial stiffness which in turn is a marker of target organ damage, in patients with type 2 diabetes. We assessed the relationship of mean HSBP or max HSBP to PWV, and compared area under the receiver-operating characteristic curve (AUC) of mean HSBP or max HSBP for arterial stiffness in 758 patients with type 2 diabetes. In the univariate analyses, age, duration of diabetes mellitus, body mass index, mean clinic systolic blood pressure (SBP), mean HSBP and max HSBP were associated with PWV. Multivariate linear regression analyses indicated that mean morning SBP (β=0.156, P=0.001) or max morning SBP (β=0.146, P=0.001) were significantly associated with PWV. AUC (95% CI) for arterial stiffness, defined as PWV equal to or more than 1800 cm per second, in mean morning SBP and max morning SBP were 0.622 (0.582-0.662; P<0.001) and 0.631 (0.591-0.670; P<0.001), respectively. Our findings implicate that max HSBP as well as mean HSBP was significantly associated with arterial stiffness in patients with type 2 diabetes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    Aoki, Shigeji; Ito, Shoko; Watanabe, Takehiko

    1979-01-01

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

  8. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  9. Evaluation of the role of damage to photosystem II in the inhibition of CO2 assimilation in pea leaves on exposure to UV-B radiation

    International Nuclear Information System (INIS)

    Nogues, S.; Baker, N.R.

    1995-01-01

    Mature pea (Pisum sativum L., cv. Meteor) leaves were exposed to two levels of UV-B radiation, with and without supplementary UV-C radiation, during 15 h photoperiods. Simultaneous measurements of CO 2 assimilation and modulated chlorophyll fluorescence parameters demonstrated that irradiation with UV-B resulted in decreases in CO 2 assimilation that are not accompanied by decreases in the maximum quantum efficiency of photosystem II (PSII) primary photochemistry. Increased exposure to UV-B resulted in a further loss of CO 2 assimilation and decreases in the maximum quantum efficiency of PSII primary photochemistry, which were accompanied by a loss of the capacity of thylakoids isolated from the leaves to bind atrazine, thus demonstrating that photodamage to PSII reaction centres had occurred. Addition of UV-C to the UV-B treatments increased markedly the rate of inhibition of photosynthesis, but the relationships between CO 2 assimilation and PSII characteristics remained the same, indicating that UV-B and UV-C inhibit leaf photosynthesis by a similar mechanism. It is concluded that PSII is not the primary target site involved in the onset of the inhibition of photosynthesis in pea leaves induced by irradiation with UV-B. (author)

  10. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  11. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    Mehnert, R.

    1999-01-01

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

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

    Science.gov (United States)

    Osuagwu, Uchechukwu L; Ogbuehi, Kelechi C

    2014-06-01

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

  13. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

    There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

  14. UV-sensitive photoreceptor protein OPN5 in humans and mice.

    Science.gov (United States)

    Kojima, Daisuke; Mori, Suguru; Torii, Masaki; Wada, Akimori; Morishita, Rika; Fukada, Yoshitaka

    2011-01-01

    A variety of animal species utilize the ultraviolet (UV) component of sunlight as their environmental cues, whereas physiological roles of UV photoreception in mammals, especially in human beings, remain open questions. Here we report that mouse neuropsin (OPN5) encoded by the Opn5 gene exhibited an absorption maximum (λmax) at 380 nm when reconstituted with 11-cis-retinal. Upon UV-light illumination, OPN5 was converted to a blue-absorbing photoproduct (λmax 470 nm), which was stable in the dark and reverted to the UV-absorbing state by the subsequent orange light illumination, indicating its bistable nature. Human OPN5 also had an absorption maximum at 380 nm with spectral properties similar to mouse OPN5, revealing that OPN5 is the first and hitherto unknown human opsin with peak sensitivity in the UV region. OPN5 was capable of activating heterotrimeric G protein Gi in a UV-dependent manner. Immuno-blotting analyses of mouse tissue extracts identified the retina, the brain and, unexpectedly, the outer ears as the major sites of OPN5 expression. In the tissue sections of mice, OPN5 immuno-reactivities were detected in a subset of non-rod/non-cone retinal neurons as well as in the epidermal and muscle cells of the outer ears. Most of these OPN5-immuno-reactivities in mice were co-localized with positive signals for the alpha-subunit of Gi. These results demonstrate the first example of UV photoreceptor in human beings and strongly suggest that OPN5 triggers a UV-sensitive Gi-mediated signaling pathway in the mammalian tissues.

  15. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E; Thomalla, E; Koepke, P [Munich Univ. (Germany). Meteorological Inst.

    1996-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  16. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E.; Thomalla, E.; Koepke, P. [Munich Univ. (Germany). Meteorological Inst.

    1995-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  17. Five years of solar UV-radiation monitoring in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Josefsson, Weine

    1996-10-01

    A network of five stations measuring the solar UV-radiation has been operated for about five years. Data are presented as plotted time-series of monthly and yearly values for the sites. A general climatology can be deduced from these data. Daily and hourly maximum values are shown for each month as indicators of the potential extreme exposure levels. The large annual variation at high latitudes is easily seen in the data set. This illustrates the importance of the solar elevation on the level of the UV-irradiance. Influence of cloud variation and of larger changes in ozone is also detectable. A few examples of the daily variation also show the strong solar elevation dependence of the UV-irradiance. The quantity and unit of the UV-radiation in this presentation is CIE-weighted irradiance expressed as MED (minimum erythermal dose), where one MED equals 210 Jm{sup -2}. The values have been recomputed to refer to the international intercomparison of broad-band meters in Helsinki in 1995. In the following named WMO-STUK 1995 scale. As will be seen there are many sources of error and detailed studies are prevented by the large uncertainty connected with these data. Due to the short period of the record and the low accuracy no attempt to study trends is done. 6 refs, 27 figs, 4 tabs

  18. Stability of 10 mg/mL cefuroxime solution for intracameral injection in commonly used polypropylene syringes and new ready-to-use cyclic olefin copolymer sterile vials using the LC-UV stability-indicating method.

    Science.gov (United States)

    Feutry, Frédéric; Simon, Nicolas; Genay, Stéphanie; Lannoy, Damien; Barthélémy, Christine; Décaudin, Bertrand; Labalette, Pierre; Odou, Pascal

    2016-01-01

    Injecting intracameral cefuroxime has been found beneficial in reducing the risk of postoperative endophthalmitis but its use has been limited through a lack of approved marketing and of ready-to-use single-units as well as the problem of aseptic compounding. Our aim was to assess a new automated primary packaging system which should ensure a higher level of sterility, thanks to its closed, sterile, ready-to-use polymer vial called "Crystal® vial". The chemical stability of a 10 mg/mL cefuroxime solution was compared in 1 mL Crystal® vials and 1 mL Luer-lock polypropylene syringes (actual reference) to eliminate any potential and specific interactions with its cyclic olefin copolymer (COC) body and elastomer stopper. Cefuroxime solution was introduced into vials and syringes and stored at -20 °C, +5 °C and +25°C/60% Relative Humidity. Cefuroxime concentration and the relative amount of the main degradation product (descarbamoyl-cefuroxime) were both determined by an HPLC/UV method indicating stability. Solutions were considered steady if the concentration remained at over 90% of the initial value. In the adapted storage conditions, the evolution of osmolality, pH and sterility was assessed. Stability profiles were identical between vials and syringes in all storage and temperature conditions. The solution was stable (cefuroxime concentration, pH and osmolality) and still sterile for 365 days at -20°C. The concentration fell below 90% after 21 days at +5 °C and after 16 h at +25°C/60%s relative humidity. The COC and thermoplastic elastomer of the vials had no impact on the degradation process confirming its possible use for a ready-to-use cefuroxime solution single-unit dose.

  19. An Induced Pluripotent Stem Cell Patient Specific Model of Complement Factor H (Y402H) Polymorphism Displays Characteristic Features of Age-Related Macular Degeneration and Indicates a Beneficial Role for UV Light Exposure.

    Science.gov (United States)

    Hallam, Dean; Collin, Joseph; Bojic, Sanja; Chichagova, Valeria; Buskin, Adriana; Xu, Yaobo; Lafage, Lucia; Otten, Elsje G; Anyfantis, George; Mellough, Carla; Przyborski, Stefan; Alharthi, Sameer; Korolchuk, Viktor; Lotery, Andrew; Saretzki, Gabriele; McKibbin, Martin; Armstrong, Lyle; Steel, David; Kavanagh, David; Lako, Majlinda

    2017-11-01

    Age-related macular degeneration (AMD) is the most common cause of blindness, accounting for 8.7% of all blindness globally. Vision loss is caused ultimately by apoptosis of the retinal pigment epithelium (RPE) and overlying photoreceptors. Treatments are evolving for the wet form of the disease; however, these do not exist for the dry form. Complement factor H polymorphism in exon 9 (Y402H) has shown a strong association with susceptibility to AMD resulting in complement activation, recruitment of phagocytes, RPE damage, and visual decline. We have derived and characterized induced pluripotent stem cell (iPSC) lines from two subjects without AMD and low-risk genotype and two patients with advanced AMD and high-risk genotype and generated RPE cells that show local secretion of several proteins involved in the complement pathway including factor H, factor I, and factor H-like protein 1. The iPSC RPE cells derived from high-risk patients mimic several key features of AMD including increased inflammation and cellular stress, accumulation of lipid droplets, impaired autophagy, and deposition of "drüsen"-like deposits. The low- and high-risk RPE cells respond differently to intermittent exposure to UV light, which leads to an improvement in cellular and functional phenotype only in the high-risk AMD-RPE cells. Taken together, our data indicate that the patient specific iPSC model provides a robust platform for understanding the role of complement activation in AMD, evaluating new therapies based on complement modulation and drug testing. Stem Cells 2017;35:2305-2320. © 2017 The Authors Stem Cells published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  20. Effect of far-UV and near-UV radiation on the cell surface charge of the protozoan Tritrichomonas foetus

    Energy Technology Data Exchange (ETDEWEB)

    Silva Filho, F C; Elias, C A; Souza, W de

    1986-05-01

    Cell electrophoresis was used to detect the effect of far-UV or near-UV radiation on the cell surface charge of the pathogenic protozoan Tritrichomonas foetus. Either far-UV or near-UV radiation interfered with the surface charge of T. foetus at fluences which inhibited cell growth by 50%. Both UV-radiations induced a significant decrease on surface charge of T. foetus, as evaluated by measurement of its electrophoretic mobility (EPM). Determinations of EPM of protozoa in solution of low ionic strength indicated that the decrease in the EPM induced by far-UV is much less pronounced that that observed for near-UV or control cells.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  2. Expression of UV-irradiated adenovirus in normal and UV-sensitive Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1985-01-01

    The chinese hamster ovary (CHO) cell mutants UV-20, UV-24, and UV-41 are abnormally sensitive to UV and harbour various defects lin their ability to repair cellular DNA. This study has examined the expression of UV-irradiated AD2 in these cells. HCR of UV-irradiated Ad2, as measured by viral structural antigen (Vag) formation or progeny production, was found to be similar for the normal and the UV-sensitive CHO strains. UV-irradiation of Ad2 (1200 J/m/sup 2/) resulted in a delay of Vag expression of 18 hours in normal human fibroblasts, which is thought to reflect the time required for removal of UV-induced lesions from the DNA before viral DNA synthesis can proceed. However, a similar UV-irradiation of Ad2 did not result in a delay of Vag expression for infection of CHO cells, suggesting that UV-induced lesions in Ad2 DNA do not inhibit its replication in CHO cells. These results indicate a fundamental difference in the processing of UV-irradiated AD2-DNA in CHO as compared to human cells

  3. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  4. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  5. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  6. Índice UV

    Science.gov (United States)

    Información general sobre el Índice UV que proporciona un pronóstico del riesgo esperado de sobreexposición a la radiación ultravioleta (UV) del sol. El índice UV va acompañado de recomendaciones para protegerse del sol.

  7. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  8. Transmission of UV-irradiance into nectarine fruit

    International Nuclear Information System (INIS)

    Blanke, M.M.

    1996-01-01

    With the global depletion of the ozone layer, leaves and fruits are increasingly exposed to UV-irradiance on the tree. Some fruits are additionally exposed postharvest to artificial germicidal W-irradiance, leading to a cumulative effect. This paper examines the transmission of UV-light (200-400 nm) by the peel of ripe nectarine fruit using UV/VIS spectrophotometry to aid understanding of UV-effects and assess the sensitivity of the peel to UV wavelengths. Yellow peel of nectarine fruit transmitted less than 0.1 % in the UV-C range of 220 to 280 nm. With longer wavelenghts, UV-light transmission increased slowly from 0.4 % at 284 nm to 1.6 % at 320 nm and, in the UV-A region, progressively from 1.9 % at 330 nm to a maximum of 13 % of incident irradiance at 400 nm. Red peel of nectarine fruit transmitted less than 0.1 % of UV-C and UV-B light, but up to 0.9 % of incident UV-A light at 400 nm. Conversely, UV-absorption of nectarine peel decreased with longer wavelengths. Hence, fruit parenchyma is more affected by UV-irradiance at wavelengths above ca. 280 nm and underneath yellow than underneath red peel

  9. Maximum likely scale estimation

    DEFF Research Database (Denmark)

    Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo

    2005-01-01

    A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...

  10. Robust Maximum Association Estimators

    NARCIS (Netherlands)

    A. Alfons (Andreas); C. Croux (Christophe); P. Filzmoser (Peter)

    2017-01-01

    textabstractThe maximum association between two multivariate variables X and Y is defined as the maximal value that a bivariate association measure between one-dimensional projections αX and αY can attain. Taking the Pearson correlation as projection index results in the first canonical correlation

  11. UV effects on bottom ice algae

    International Nuclear Information System (INIS)

    Ryan, K.; Buckley, B.

    1993-01-01

    Antarctic sea ice can be surprisingly transparent to UV radiation, particularly during spring when ozone depletion reaches a maximum. A 5% reduction in photosynthetic production was observed in laboratory experiments for UVB levels expected under the ice at this time. In situ studies modifying the UVB radiation falling onto algae were inconclusive. (author). 5 refs

  12. Single-strand breaks in supercoiled DNA induced by vacuum-UV radiation in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Takakura, Kaoru; Ishikawa, Mitsuo; Hieda, Kotaro; Kobayashi, Katsumi; Ito, Atsushi; Ito, Takashi

    1986-09-01

    The induction of single-strand breaks in the DNA of plasmid pBR 322 by vacuum-UV radiation above 145 nm in aqueous solutions was studied in relation to the production of OH-radicals in water. The similarity and dissimilarity were examined on the wavelength dependence between the two effects. The maximum of single strand breaks at 150 nm could be explained by the action of OH-radicals derived from direct water photolysis: the maximum at 180 nm remains unexplained. There was no indication that the direct absorption of photon by the DNA molecule plays an important role in the production of single-strand breaks.

  13. Single-strand breaks in supercoiled DNA induced by vacuum-UV radiation in aqueous solution

    International Nuclear Information System (INIS)

    Takakura, Kaoru; Ishikawa, Mitsuo; Hieda, Kotaro; Kobayashi, Katsumi; Ito, Atsushi; Ito, Takashi

    1986-01-01

    The induction of single-strand breaks in the DNA of plasmid pBR 322 by vacuum-UV radiation above 145 nm in aqueous solutions was studied in relation to the production of OH-radicals in water. The similarity and dissimilarity were examined on the wavelength dependence between the two effects. The maximum of single strand breaks at 150 nm could be explained by the action of OH-radicals derived from direct water photolysis: the maximum at 180 nm remains unexplained. There was no indication that the direct absorption of photon by the DNA molecule plays an important role in the production of single-strand breaks. (author)

  14. Silicon nanoparticles more effectively alleviated UV-B stress than silicon in wheat (Triticum aestivum) seedlings.

    Science.gov (United States)

    Tripathi, Durgesh Kumar; Singh, Swati; Singh, Vijay Pratap; Prasad, Sheo Mohan; Dubey, Nawal Kishore; Chauhan, Devendra Kumar

    2017-01-01

    The role of silicon (Si) in alleviating biotic as well as abiotic stresses is well known. However, the potential of silicon nanoparticle (SiNP) in regulating abiotic stress and associated mechanisms have not yet been explored. Therefore, in the present study hydroponic experiments were conducted to investigate whether Si or SiNp are more effective in the regulation of UV-B stress. UV-B (ambient and enhanced) radiation caused adverse effect on growth of wheat (Triticum aestivum) seedlings, which was accompanied by declined photosynthetic performance and altered vital leaf structures. Levels of superoxide radical and H 2 O 2 were enhanced by UV-B as also evident from their histochemical stainings, which was accompanied by increased lipid peroxidation (LPO) and electrolyte leakage. Activities of superoxide dismutase and ascorbate peroxidase were inhibited by UV-B while catalase and guaiacol peroxidase, and all non-enzymatic antioxidants were stimulated by UV-B. Although, nitric oxide (NO) content was increased at all tested combinations, but its maximum content was observed under SiNps together with UV-B enhanced treatment. Pre-additions of SiNp as well as Si protected wheat seedlings against UV-B by regulating oxidative stress through enhanced antioxidants. Data indicate that SiNp might have protected wheat seedlings through NO-mediated triggering of antioxidant defense system, which subsequently counterbalance reactive oxygen species-induced damage to photosynthesis. Further, SiNp appear to be more effective in reducing UV-B stress than Si, which is related to its greater availability to wheat seedlings. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  16. Ifp's New Flexible Hydrocracking Process Combines Maximum Conversion with Production of High Viscosity, High Vi Lube Stocks Le nouveau procédé IFP d'hydrocraquage à haute flexibilité combine conversion maximum et production de bases, huile à haute viscosité et à indice de viscosité élevé

    Directory of Open Access Journals (Sweden)

    Hennico A.

    2006-11-01

    Full Text Available Institut Français du Pétrole (IFP has developed a new dual catalytic system for its hydrocracking process that enables high conversion to middle distillates and production of high viscosity, high VI lube stocks. Although the hydrocracking process is mainly devoted to the conversion of vacuum distillates, deasphalted oil or mixture of both into high quality middle distillates, it can also produce a residue, that after dewaxing will be a very high VI lube base oil. In this presentation major emphasis is put on the possibility to produce very high VI lubes with high viscosity thanks to the development of the new catalytic system. Large flexibility in feedstock selection and easy control of operating variables allow the production of all grades of lube oils associated with high quality middle distillates for a large range of conversion levels. L'Institut Français du Pétrole (IFP a mis au point, pour son procédé d'hydrocraquage, un nouveau système catalytique à 2 catalyseurs qui permet une forte conversion en distillats moyens et la production de fractions lubrifiantes à haute viscosité et indice de viscosité élevé. Si le procédé d'hydrocraquage est essentiellement utilisé pour la conversion de distillats sous vide, d'huile désasphaltée ou d'un mélange des deux en distillats moyens de haute qualité, il peut aussi produire un résidu qui, après déparaffinage, fournira une base pour lubrifiant à indice de viscosité très élevé. Cet article souligne particulièrement la possibilité de produire des lubrifiants à indice de viscosité très élevé et haute viscosité, grâce à ce nouveau système catalytique. Une grande flexibilité dans le choix des produits à traiter et la facilité de contrôle des paramètres opératoires permet la production de toutes les qualités d'huiles lubrifiantes associées à des distillats moyens de haute qualité, pour une large gamme de niveaux de conversion.

  17. Maximum power point tracking

    International Nuclear Information System (INIS)

    Enslin, J.H.R.

    1990-01-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

  18. Índices morfogênicos e de crescimento durante o estabelecimento e a rebrotação do capim-Mombaça (Panicum maximum Jacq. Morphogenic traits and growth indices during the establishment and regrowth of Mombaçagrass (Panicum maximum Jacq.

    Directory of Open Access Journals (Sweden)

    Carlos Augusto de Miranda Gomide

    2003-08-01

    Full Text Available Com o objetivo de estimar as características morfogênicas e os índices de crescimento do capim-Mombaça, um ensaio foi conduzido em casa de vegetação. Estudou-se o desenvolvimento das plantas em três crescimentos: o crescimento seminal de estabelecimento (C1, o da brotação após corte ao 16º dia (C2 e 37º dia (C3 do crescimento de estabelecimento. As variáveis estimadas foram: índices de crescimento [taxa de crescimento relativo (TCR, taxa assimilatória líquida (TAL e razão de área foliar (RAF], e os índices morfogênicos [taxa de aparecimento foliar (TApF, taxa de alongamento foliar (TAlF, taxa de expansão da área foliar e taxa de senescência foliar]. Colheitas foram feitas ao longo do desenvolvimento das plantas em cada crescimento considerado: 13, 20, 27, 42, 55, 69 e 83 dias após emergência (C1; 0, 3, 6, 10, 17, 24, 38, 52 e 66 dias após o corte aos 16 dias (C2 e 0, 1, 3, 7, 21, 35, 49, 63 e 77 dias após o corte aos 37 dias (C3. Foram observadas três repetições (vasos, segundo delineamento inteiramente casualizado. Altos valores de TAL, RAF e TCR foram observados no início do crescimento seminal (C1 das plantas, caindo assintoticamente com o avanço da idade. O corte aos 37 dias de idade comprometeu o crescimento das plantas expresso em seus valores de TApF, a TAlF e a taxa de expansão da área foliar, RAF, TAL e TCR, sendo observados valores negativos para estes dois últimos índices, nos primeiros dias de brotação. A baixa demanda respiratória e a alocação de fotoassimilados para o crescimento foliar garantiram às plantas cortadas aos 16 dias, balanço positivo de carbono, possibilitando sua rápida recuperação.A trial was carried out in green-house to estimate morphogenic traits and growth indices of Mombaçagrass development. Three growths were considered: the seminal, establishment growth (G1 and the regrowths following a clipping taken on the 16th (G2 and 37th (G3 days of the seminal growth. The

  19. Comets in UV

    Science.gov (United States)

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

    2018-04-01

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

  20. The effect of UV-B and UV-C radiation on Hibiscus leaves determined by ultraweak luminescence and fluorescence induction [chlorophyll fluorescence induction, ultraweak luminescence

    International Nuclear Information System (INIS)

    Panagopoulos, I.; Bornman, J.F.; Björn, L.O.

    1989-01-01

    The effects of UV-C (254 nm) and UV-B (280-320 nm) on chlorophyll fluorescence induction and ultraweak luminescence (UL) in detached leaves of Hibiscus rosa-sinensis L. were investigated. UL from leaves exposed to UV-B and UV-C radiation reached a maximum 72 h after irradiation. In both cases most of the light was of a wavelength over 600 nm. An increase in the percentage of long wavelength light with time was detected. UV radiation increased peroxidase activity, which also reached a maximum 72 h after irradiation. UV-B and UV-C both reduced variable chlorophyll fluorescence. No effect on the amount of chlorophyll or UV screening pigments was observed with the short-term irradiation used in this investigation. (author)

  1. UV-irradiation effects on polyester nuclear track detector

    International Nuclear Information System (INIS)

    Agarwal, Chhavi; Kalsi, P.C.

    2010-01-01

    The effects of UV irradiation (λ=254 nm) on polyester nuclear track detector have been investigated employing bulk-etch technique, UV-visible spectrophotometry and infra-red spectrometry (FTIR). The activation energy values for bulk-etching were found to decrease with the UV-irradiation time indicating the scission of the polymer. Not much shift in the absorption edge due to UV irradiation was seen in the UV-visible spectra. FTIR studies also indicate the scission of the chemical bonds, thereby further validating the bulk-etch rate results.

  2. UV spectrophotometry of the Metronidazole

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-10-01

    Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

  3. UV exposure in cars.

    Science.gov (United States)

    Moehrle, Matthias; Soballa, Martin; Korn, Manfred

    2003-08-01

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

  4. Maximum entropy methods

    International Nuclear Information System (INIS)

    Ponman, T.J.

    1984-01-01

    For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)

  5. UV-induced effects

    NARCIS (Netherlands)

    Liebsch, M.; Spielmann, H.; Pape, W.; Krul, C.; Deguercy, A.; Eskes, C.A.M.

    2005-01-01

    Regulatory requirements: According to the current Notes for Guidance of the Scientific Committee on Cosmetic Products and Non-Food Products (SCCNFP), cosmetic ingredients and mixtures of ingredients absorbing UV light (in particular UV filter chemicals used, for example, to ensure the light

  6. Dose effect of the uvsA+ gene product in duplication strains of Aspergillus nidulans

    International Nuclear Information System (INIS)

    Majerfeld, I.H.; Roper, J.A.

    1978-01-01

    Strains of Aspergillus nidulans which carry a particular segment of chromosome I in duplicate - one segment in normal position, the other translocated to chromosome II - are more resistant to uv light than are strains with a balanced haploid genome. A double dose of the uvsA + allele, carried on the duplicate segment, determines this enhanced resistance; this is shown by the descending order of resistance of duplication haploids uvsA + /uvsA + , uvsA1/uvsA + and uvsA1/uvsA1. An unbalanced diploid with three doses of the uvsA + allele also shows greater resistance than a balanced uvsA + //uvsA + diploid. However, in balanced diploids the uvsA1 allele appears to be completely recessive; uvsA + //uvsA + and uvsA + //uvsA1 diploids produce indistinguishable survival curves after uv irradiation. Thus, the uvsA + gene product is not rate-limiting in repair processes in strains with a balanced genome. The rate-limiting effect observed in these unbalanced strains presumably reflects an interaction of the uvsA + product and other functions determined by the rest of the genome. Duplication haploids and normal haploids lose photorepairable lesions at similar rates. This observation may be interpreted to indicate that differences in survival are not due to differences in the efficiency of excision of uv-induced pyrimidime dimers

  7. The last glacial maximum

    Science.gov (United States)

    Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

    2009-01-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

  8. Effect of UV/ozone treatment on the nanoscale surface properties of gold implanted polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Kisić, Danilo; Nenadović, Miloš [INS Vinca, Laboratory of Atomic Physics, University of Belgrade, Mike Alasa 12-14, 11001 Belgrade (Serbia); Štrbac, Svetlana [ICTM Institute of Electrochemistry, University of Belgrade, Njegoseva 12, 11001 Belgrade (Serbia); Adnadjević, Borivoj [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Rakočević, Zlatko, E-mail: zlatkora@vinca.rs [INS Vinca, Laboratory of Atomic Physics, University of Belgrade, Mike Alasa 12-14, 11001 Belgrade (Serbia)

    2014-07-01

    The effect of ultraviolet (UV) ozone treatment on the surface properties of gold implanted high density polyethylene (HDPE) was investigated at a nanoscale using Atomic Force Microscopy (AFM). HDPE samples were modified by the implantation of gold ions at a dose of 5 × 10{sup 15} ions/cm{sup 2}, using energies of 50, 100, 150, and 200 keV, and subsequently treated with UV/ozone. AFM surface topography images revealed that after UV/ozone treatment, the surface roughness of all Au/HDPE samples increased, while Power Spectral Density function increased only for samples implanted using higher energies, with a maximum for 150 keV. The chemical surface composition was homogenous in all cases, which was evidenced by the appearance of single peaks in the histograms obtained from the phase AFM images. For UV/ozone treated samples, the shift of the peaks positions in the histograms to the higher values of the phase lag with respect to untreated ones indicated the decrease of surface hardness. Besides, a significant change of fractal dimension of surface grains is observed after UV/ozone treatment.

  9. A flavonoid mutant of barley (Hordeum vulgare L.) exhibits increased sensitivity to UV-B radiation in the primary leaf

    International Nuclear Information System (INIS)

    Reuber, S.; Bornman, J.F.; Weissenböck, G.

    1996-01-01

    The aim of the present investigation was to define the role of soluble flavonoids as UV-B protectants in the primary leaf of barley (Hordeum vulgare L.). For this purpose we used a mutant line (Ant 287) from the Carlsberg collection of proanthocyanidin-free barley containing only 7% of total extractable flavonoids in the primary leaf as compared to the mother variety (Hiege 550/75). Seven-day-old leaves from plants grown under high visible light with or without supplementary UV-B radiation were used for the determination of UV-B sensitivity. UV-B-induced changes were assessed from parameters of chlorophyll fluorescence of photosystem II, including initial and maximum fluorescence, apparent quantum yield, and photochemical and non-photochemical quenching. A quartz fibre-optic microprobe was used to evaluate the amount of potentially harmful UV-B (310 nm radiation) penetrating into the leaf as a direct consequence of flavonoid deficiency. Our data indicate an essential role of flavonoids in UV-B protection of barley primary leaves. In leaves of the mutant line grown under supplementary UV-B, an increase in 310nm radiation in the mesophyll and a strong decrease in the quantum yield of photosynthesis were observed as compared to the corresponding mother variety. Primary leaves of liege responded to supplementary UV-B radiation with a 30% increase in the major flavonoid saponarin and a 500% increase in the minor compound lutonarin. This is assumed to be an efficient protective response since no changes in variable chlorophyll fluorescence were apparent. In addition, a further reduction in UV-B penetration into the mesophyll was recorded in these leaves

  10. Maximum Entropy Fundamentals

    Directory of Open Access Journals (Sweden)

    F. Topsøe

    2001-09-01

    Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over

  11. Changes in UV absorption of sunscreens after UV irradiation

    Science.gov (United States)

    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.

  12. Probable maximum flood control

    International Nuclear Information System (INIS)

    DeGabriele, C.E.; Wu, C.L.

    1991-11-01

    This study proposes preliminary design concepts to protect the waste-handling facilities and all shaft and ramp entries to the underground from the probable maximum flood (PMF) in the current design configuration for the proposed Nevada Nuclear Waste Storage Investigation (NNWSI) repository protection provisions were furnished by the United States Bureau of Reclamation (USSR) or developed from USSR data. Proposed flood protection provisions include site grading, drainage channels, and diversion dikes. Figures are provided to show these proposed flood protection provisions at each area investigated. These areas are the central surface facilities (including the waste-handling building and waste treatment building), tuff ramp portal, waste ramp portal, men-and-materials shaft, emplacement exhaust shaft, and exploratory shafts facility

  13. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1988-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. We review the need for such methods in data analysis and show, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. We conclude with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  14. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1989-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. The author reviews the need for such methods in data analysis and shows, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. He concludes with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  15. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    MAF outperforms the functional PCA in concentrating the interesting' spectra/shape variation in one end of the eigenvalue spectrum and allows for easier interpretation of effects. Conclusions. Functional MAF analysis is a useful methods for extracting low dimensional models of temporally or spatially......Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in......\\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  16. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  17. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  18. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  19. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  20. UV-induced N2O emission from plants

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2014-01-01

    investigate for the fi rst time N 2 O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted fi eld site measurements to investigate N 2 O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory...... magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N 2 O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process...

  1. Interrelations of UV-global/global/diffuse solar irradiance components and UV-global attenuation on air pollution episode days in Athens, Greece

    International Nuclear Information System (INIS)

    Koronakis, P.S.; Sfantos, G.K.

    2002-01-01

    An investigation of global ultraviolet (G UV ), global (G) and diffuse (G d ) solar intensities, continuously recorded over a period of five years at a station in Athens, Greece, and stored on the basis of hourly time intervals since 1996, has revealed the following: (a) UV-global irradiation, associated with the 290-395 nm wavelength region, constitutes 4.1% of global solar. (b) UV-global irradiance ranges from an average minimum of 2.4 W m -2 and 3.1% of global solar in January to an average maximum of 45 W m -2 and 7.8%, respectively, in June, both considered at 13:00, solar time. (c) There exists a good correlation among the two dimensionless irradiance ratios G UV /G d and G d /G in the form of an exponential relationship. (d) UV-global monthly irradiation data show evidence of temporal variability in Athens, from 1996 to 2000. (e) Anthropogenic and photochemical atmospheric pollutant agents (O 3 , CO, SO 2 , NO x , smoke) causing air pollution episodes seem to affect differently solar irradiance components. The main results of analysis (measurements within ± 2 h from solar noon) indicate that a buildup of O 3 and NO x inside the urban Athens plume during cloudless and windless warm days could cause: (i) UV-global irradiance depletion between 5.4% and 14.4%. (ii) Diffuse solar irradiance enhancement up to 38.1%. (iii) Global solar irradiance attenuation ranging up to 6.3%. (author)

  2. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-15

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

  4. Monitoring and control of UV and UV-TiO{sub 2} disinfections for municipal wastewater reclamation using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chuang-Hung [Department of Architecture, National United University, Miao-Li 360, Taiwan, ROC (China); Yu, Ruey-Fang, E-mail: rfyu@nuu.edu.tw [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China); Cheng, Wen-Po; Liu, Chun-Ru [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer ANN models can effectively control both UV and UV-TiO{sub 2} disinfections for wastewater reuse. Black-Right-Pointing-Pointer Comparing to UV disinfection, UV-TiO{sub 2} disinfection can save 13.2-15.7% of UV dosage and capacity. Black-Right-Pointing-Pointer SS decreases disinfection efficiency when UV doses were <10,000 {mu}W s/cm{sup 2}. - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO{sub 2} can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO{sub 2} disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO{sub 2} disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO{sub 2} disinfections. A novel ANN control strategy is applied to control UV and UV-TiO{sub 2} disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO{sub 2} disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO{sub 2} disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2-15.7%.

  5. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Chevremont, A.-C., E-mail: anne-celine.chevremont@imbe.fr [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France); Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Farnet, A.-M. [Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Coulomb, B.; Boudenne, J.-L. [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France)

    2012-06-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO{sub 2}. - Highlights: Black-Right-Pointing-Pointer We test UV-LEDs as an urban wastewater tertiary treatment. Black-Right-Pointing-Pointer UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. Black-Right-Pointing-Pointer Coupled wavelengths have the most efficient bactericidal effect. Black-Right-Pointing-Pointer Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

  6. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    International Nuclear Information System (INIS)

    Chevremont, A.-C.; Farnet, A.-M.; Coulomb, B.; Boudenne, J.-L.

    2012-01-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO 2 . - Highlights: ► We test UV-LEDs as an urban wastewater tertiary treatment. ► UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. ► Coupled wavelengths have the most efficient bactericidal effect. ► Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

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

    Directory of Open Access Journals (Sweden)

    José Aguilera

    2008-03-01

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

  8. Road Signs for UV-Completion

    CERN Document Server

    Dvali, Gia; Gomez, Cesar

    2012-01-01

    We confront the concepts of Wilsonian UV-completion versus self-completion by Classicalization in theories with derivatively-coupled scalars. We observe that the information about the UV-completion road is encoded in the sign of the derivative terms. We note that the sign of the derivative couplings for which there is no consistent Wilsonian UV-completion is the one that allows for consistent classicalons. This is an indication that for such a sign the vertex must be treated as fundamental and the theory self-protects against potential inconsistencies, such as superluminality, via self-completion by classicalization. Applying this reasoning to the UV-completion of the Standard Model, we see that the information about the Higgs versus classicalization is encoded in the sign of the scattering amplitude of longitudinal W-bosons. Negative sign excludes Higgs or any other weakly-coupled Wilsonian physics.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-15

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

  10. Response surface methodology as a tool for modeling and optimization of Bacillus subtilis spores inactivation by UV/ nano-Fe0 process for safe water production.

    Science.gov (United States)

    Yousefzadeh, Samira; Matin, Atiyeh Rajabi; Ahmadi, Ehsan; Sabeti, Zahra; Alimohammadi, Mahmood; Aslani, Hassan; Nabizadeh, Ramin

    2018-04-01

    One of the most important aspects of environmental issues is the demand for clean and safe water. Meanwhile, disinfection process is one of the most important steps in safe water production. The present study aims at estimating the performance of UV, nano Zero-Valent Iron particles (nZVI, nano-Fe 0 ), and UV treatment with the addition of nZVI (combined process) for Bacillus subtilis spores inactivation. Effects of different factors on inactivation including contact time, initial nZVI concentration, UV irradiance and various aerations conditions were investigated. Response surface methodology, based on a five-level, two variable central composite design, was used to optimize target microorganism reduction and the experimental parameters. The results indicated that the disinfection time had the greatest positive impact on disinfection ability among the different selected independent variables. According to the results, it can be concluded that microbial reduction by UV alone was more effective than nZVI while the combined UV/nZVI process demonstrated the maximum log reduction. The optimum reduction of about 4 logs was observed at 491 mg/L of nZVI and 60 min of contact time when spores were exposed to UV radiation under deaerated condition. Therefore, UV/nZVI process can be suggested as a reliable method for Bacillus subtilis spores inactivation. Copyright © 2018. Published by Elsevier Ltd.

  11. Modeling Alkyl p-Methoxy Cinnamate (APMC) as UV absorber based on electronic transition using semiempirical quantum mechanics ZINDO/s calculation

    Science.gov (United States)

    Salmahaminati; Azis, Muhlas Abdul; Purwiandono, Gani; Arsyik Kurniawan, Muhammad; Rubiyanto, Dwiarso; Darmawan, Arif

    2017-11-01

    In this research, modeling several alkyl p-methoxy cinnamate (APMC) based on electronic transition by using semiempirical mechanical quantum ZINDO/s calculation is performed. Alkyl cinnamates of C1 (methyl) up to C7 (heptyl) homolog with 1-5 example structures of each homolog are used as materials. Quantum chemistry-package software Hyperchem 8.0 is used to simulate the drawing of the structure, geometry optimization by a semiempirical Austin Model 1 algorithm and single point calculation employing a semiempirical ZINDO/s technique. ZINDO/s calculations use a defined criteria that singly excited -Configuration Interaction (CI) where a gap of HOMO-LUMO energy transition and maximum degeneracy level are 7 and 2, respectively. Moreover, analysis of the theoretical spectra is focused on the UV-B (290-320 nm) and UV-C (200-290 nm) area. The results show that modeling of the compound can be used to predict the type of UV protection activity depends on the electronic transition in the UV area. Modification of the alkyl homolog relatively does not change the value of wavelength absorption to indicate the UV protection activity. Alkyl cinnamate compounds are predicted as UV-B and UV-C sunscreen.

  12. Effect of far-UV and near-UV radiation on the cell surface charge of the protozoan Tritrichomonas foetus

    International Nuclear Information System (INIS)

    Silva Filho, F.C.; Elias, C.A.; Souza, W. de

    1986-01-01

    Cell electrophoresis was used to detect the effect of far-UV or near-UV radiation on the cell surface charge of the pathogenic protozoan Tritrichomonas foetus. Either far-UV or near-UV radiation interfered with the surface charge of T. foetus at fluences which inhibited cell growth by 50%. Both UV-radiations induced a significant decrease on surface charge of T. foetus, as evaluated by measurement of its electrophoretic mobility (EPM). Determinations of EPM of protozoa in solution of low ionic strength indicated that the decrease in the EPM induced by far-UV is much less pronounced that that observed for near-UV or control cells. (author)

  13. Maximum concentrations at work and maximum biologically tolerable concentration for working materials 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The meaning of the term 'maximum concentration at work' in regard of various pollutants is discussed. Specifically, a number of dusts and smokes are dealt with. The valuation criteria for maximum biologically tolerable concentrations for working materials are indicated. The working materials in question are corcinogeneous substances or substances liable to cause allergies or mutate the genome. (VT) [de

  14. Study of induced functions by UV in Staphylococcus

    International Nuclear Information System (INIS)

    Silva, B.S. da.

    1982-01-01

    SOS functions induced by ultraviolet (UV) radiation were studied using S. aureus and S. epidermidis. Comparing the results obtained from these two organisms with those described in the literature for E. coli allows us to conclude: the difference in UV sensibility between the lysogenic and non-lysogenic strains of Staphylococcus is extremely large; the dose of UV radiation which results in the maximum induction of the lysogenic strains lead to 99% inactivation of the lysogenic strains; the kinetics of prophage liberation in lysogenic cultures of Staphylococcus is more rapid than those described for E. coli; the dose of UV radiation is much lower than the dose described for E. coli; the maximum W-reactivatio and W-mutagenesis are obtained immediately after the irradiation or within the 15 minutes allowed for the phage adsorption. (author)

  15. UV-A enhanced growth and UV-B induced positive effects in the recovery of photochemical yield in Gracilaria lemaneiformis (Rhodophyta).

    Science.gov (United States)

    Xu, Juntian; Gao, Kunshan

    2010-09-02

    The effects of solar UV radiation (280-400 nm) on growth, quantum yield and pigmentation in Gracilaria lemaneiformis were investigated when the thalli were cultured under solar radiation with or without UV for a period of 15 days. Presence of UV-A (315-400 nm) enhanced the relative growth rate, while UV-B (218-315 nm) inhibited it. The positive effect of UV-A and negative effect of UV-B counteracted to result in an insignificant impact of UVR on growth. During the noon period, both UV-A and UV-B resulted in the decrease of maximum quantum yield (Fv/Fm), but UV-B aided in the recovery of the yield in the late afternoon, reflecting that UV-B might be used as a signal in photorepair processes. UV induced the accumulation of UV-absorbing compounds (UVAC) to defend against the harmful UVR. However, the accumulation of UVAC took a much longer time compared to that previously reported, which was probably due to the lower levels of solar radiation and water temperature in the early spring period. Unknown UV-absorbing compounds (UVAC), which peaked at 265 nm, probably the precursor of MAAs (UVAC(325)), accumulated under moderate levels of solar radiation and were transformed to MAAs under higher solar radiation. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  16. Surface contamination to UV-curable acrylates in the furniture and parquet industry.

    Science.gov (United States)

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

    2001-03-01

    Surface contamination to ultraviolet radiation curable coatings (UV coatings), used increasingly in the parquet and furniture industry, is a matter of concern as a source for skin contamination. UV coatings contain chemically and biologically reactive acrylates, well known as skin contact irritants and sensitizers. Surface contamination may spread secondarily to equipment and other unexpected areas even outside the workplace. Yet, studies concerning this type of contamination are lacking due to lack of suitable sampling methods. Surface contamination of the work environment with risk for skin exposure to UV coating was measured employing a quantitative adhesive tape sampling method developed for this purpose. A pilot study was first performed at three workplaces to evaluate the contamination. In the main study, we wanted to locate and identify in detail the surface contamination of areas where problems exist, and to determine the extent of the problem. Measurements were performed at seven workplaces on two separate workdays (round 1 and 2) within a six-month period. Samples were collected from the workplaces based on the video monitoring of skin contact frequency with the surfaces and categorized into three groups to analyze risk. The pilot study indicated that surface contamination to TPGDA containing UV coatings was common, found in 76 percent of the surfaces, and varied with a maximum of 909 microg TPGDA 10 cm(-2) sampling area. In the main study TPGDA was found in 153 out of 196 collected samples (78.1%); for round one 78.1 percent (82 out of 105 samples) and for round two 78.0 percent (71 out of 91 samples). The average TPGDA mass on positive surface samples was on the first round 2,247 +/- 7,462 microg, and on the second round 2,960 +/- 4,590 microg. We conclude that surface contamination to uncured UV coatings at UV-curing lines is common and this involves a risk for harmful, unintentional skin exposure to acrylates.

  17. A study on UV irradiated HDPE

    International Nuclear Information System (INIS)

    Sang Haibo; Liu Zimin; Wu Shishan; Shen Jian

    2006-01-01

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

  18. Mutational synergism between p-fluorophenylalaline and UV in Coprinus lagopus

    International Nuclear Information System (INIS)

    Talmud, P.J.

    1977-01-01

    The amino acid analogue p-fluorophenylalanine (PFP) is mutagenic to Coprinus lagopus due to its incorporation into proteins. Spontaneous mutations, PFP and UV mutagenesis and PFP/UV synergism have been studied in a UV resistant strain and in two complementing UV sensitive mutant strains. By comparison to the UV resistant strain, one UV sensitive strain shows normal spontaneous mutations, 1.4% PFP-induced mutations and 50-fold UV mutagenesis. The second UV sensitive strain has 19-fold spontaneous mutation frequency and slightly elevated UV mutagenesis. In all 3 strains the PFP/UV synergism is comparable (4-5 times the arithmetic expected). The results indicate that PFP mutagenesis is due to the incorporation of PFP into enzymes normally functioning in the organism but which also participate in UV repair mechanisms. A model is proposed for UV repair which is based on a PFP sensitive excision repair system of at least two enzymes, an alternative 'error-proof' pathway which is not susceptible to PFP and an 'error-prone' pathway which is responsible for UV mutagenesis and is susceptible to PFP as shown by the PFP/UV synergism. Because PFP is given before UV treatment, this implies a UV inducible cofactor and a PFP sensitive enzyme which only functions after UV activation

  19. UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

    Directory of Open Access Journals (Sweden)

    Ricarda Modarressie

    2015-05-01

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

  20. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

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

  1. Changes of diffuse UV-B radiation on clear sky days

    International Nuclear Information System (INIS)

    Kon, H.; Ichibayashi, R.; Matsuoka, N.

    2004-01-01

    Measurements of global and diffuse UV-B radiation have been carried out in Matsudo City (35.3 deg N, 139.9 deg E), Japan. Forty clear sky days were chosen and the annual variation of global and diffuse UV-B radiation was analyzed. The dependence of the diffuse component on visibility was also examined. The results are summarized as follows. 1. The maximum of daily global UV-B was beyond 40kJrec mE-2 daysup(-1) and was recorded in late July. The maximum of daily diffuse UV-B was recorded in early July. There was a tendency for the diffuse UV-B to be larger than the direct UV-B during a year in Matsudo. 2. The fraction of diffuse UV-B to global UV-B changed a lot each day. The observed minimum value of the fraction during a year was recorded in early August. 3. There was a tendency for the fraction of diffuse UV-B to global UV-B to decrease when visibility increased. 4. The diffuse components that change a lot each day were properly estimated by using the expected minimum fraction and visibility. Key words: Diffuse UV-B, Ultraviolet, UV-B, Visibility

  2. UV-induced lethal sectoring and pure mutant clones in yeast.

    Science.gov (United States)

    Hannan, M A; Duck, P; Nasim, A

    1976-08-01

    The induction of lethal sectoring and pure mutant clones by ultraviolet light has been studied in a homogeneous G1 population of Saccharomyces cerevisiae grown in a normal growth medium. At the lowest UV dose of 250 ergs, which corresponds to a shoulder in the survival curve, all mutants appeared as pure clones. At higher doses the frequency of mosaic mutants progressively increased. These results indicate a relationship between the highest frequency of complete mutants and the maximum repair activity. In addition, the frequency of lethal sectoring at all doses tested was too low to account for the origin of pure mutant clones.

  3. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

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

    2011-01-01

    , nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  4. Enhanced UV-B radiation alleviates the adverse effects of summer drought in two Mediterranean pines under field conditions [ozone depletion

    International Nuclear Information System (INIS)

    Petropoulou, Y.; Kyparissis, A.; Nikolopoulos, D.; Manetas, Y.

    1995-01-01

    The effects of enhanced UV-B (290-320 nm) radiation on two native Mediterranean pines (Pinus pinea L., Pinus halepensis Mill.) were recorded during a one-year field study. Plants received ambient or ambient plus supplemental UV-B radiation (simulating a 15% stratospheric ozone depletion over Patras. Greece, 38.3°N. 29.1°E) and only natural precipitation, i.e. they were simultaneously exposed to other natural stresses. particularly water stress during summer. Supplemental UV-B irradiation started in early February, 1993 and up to late June, no effects were observed on growth and photochemical efficiency of photosystem II, as measured by chlorophy II fluorescence induction. Water stress during the summer was manifested in the control plants as a decline in the ratio of variable to maximum fluorescence (F v /F m ), the apparent photon yield for oxygen evolution (φ I ) and the photosynthetic capacity at 5% CO 2 (P m ). In addition, a partial needle loss was evident. Under supplemental UV-B radiation, however, the decreases in F v /F m , φ i , and P m . as well as needle losses were significantly less. Soon after the first heavy autumn rains. photosynthetic parameters in both control and UV-B treated plants recovered to similar values. but the transient summer superiority of UV-B irradiated plants resulted in a significant increase in their dry weight measured at plant harvest. during late January. 1994. Plant height. UV-B absorbing compounds, photosynthetic pigments and relative water content measured at late spring. late summer and at plant harvest, were not significantly affected by supplemental UV-B radiation. The results indicate that enhanced UV-B radiation may be beneficial for Mediterranean pines through a partial alleviation of the adverse effects of summer drought. (author)

  5. Credal Networks under Maximum Entropy

    OpenAIRE

    Lukasiewicz, Thomas

    2013-01-01

    We apply the principle of maximum entropy to select a unique joint probability distribution from the set of all joint probability distributions specified by a credal network. In detail, we start by showing that the unique joint distribution of a Bayesian tree coincides with the maximum entropy model of its conditional distributions. This result, however, does not hold anymore for general Bayesian networks. We thus present a new kind of maximum entropy models, which are computed sequentially. ...

  6. Biobased Nanoparticles for Broadband UV Protection with Photostabilized UV Filters

    NARCIS (Netherlands)

    Hayden, D.R.|info:eu-repo/dai/nl/412640694; Imhof, A.|info:eu-repo/dai/nl/145641600; Velikov, K. P.|info:eu-repo/dai/nl/239483472

    2016-01-01

    Sunscreens rely on multiple compounds to provide effective and safe protection against UV radiation. UV filters in sunscreens, in particular, provide broadband UV protection but are heavily linked to adverse health effects due to the generation of carcinogenic skin-damaging reactive oxygen species

  7. UV dissociation of vibrationally excited UF6

    International Nuclear Information System (INIS)

    Alexandre, M.; Clerc, M.; Gagnon, R.; Gilbert, M.; Isnard, P.; Nectoux, P.; Rigny, P.; Weulersse, J.M.

    1983-01-01

    Before application of laser photodissociation of UF 6 to the separation of uranium isotopes becomes practical, isotopic selectivity should be optimized. We present here results on the cross sections involved in the irradiation of UF 6 simultaneously with infrared and ultraviolet lasers, as a function of wavelengths, fluence and temperature (at 293 K and 105 K, in an adiabatic expansion). The experiment uses a Nd 3+ YAG pumped lithium niobate optical parametric oscillator as a tunable 16 μ light source. Energies of the order of 1 mJ can be obtained with linewidths smaller than 0.1 cm - . The UV source used is based on ND 3+ YAG pumped dye laser and various frequency mixing schemes. At low temperature the frequency variation of the absorbed infrared energy per molecule depends markedly on the IR fluence phisub(IR) with a maximum value varying as phisub(IR)sup(-1/2) and a frequency extension far beyond the low level absorption spectrum. The absorbed vibrational energy leads to a change in the UV cross section comparable with the effect of a rise in temperature. Using this a model is put forward to express the isotopic selectivity 235 U/ 238 U as a function of UV wavelength and IR irradiation conditions. Experimental results agree with this model, and yield to maximum selectivity close to two [fr

  8. Radiative flux calculations at UV and visible wavelengths

    International Nuclear Information System (INIS)

    Grossman, A.S.; Grant, K.E.; Wuebbles, D.J.

    1993-10-01

    A radiative transfer model to calculate the short wavelength fluxes at altitudes between 0 and 80 km has been developed at LLNL. The wavelength range extends from 175--735 nm. This spectral range covers the UV-B wavelength region, 250--350 nm, with sufficient resolution to allow comparison of UV-B measurements with theoretical predictions. Validation studies for the model have been made for both UV-B ground radiation calculations and tropospheric solar radiative forcing calculations for various ozone distributions. These studies indicate that the model produces results which agree well with respect to existing UV calculations from other published models

  9. Optimizing UV Index determination from broadband irradiances

    Science.gov (United States)

    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

  10. Plasmid mediated enhancement of uv resistance in Streptococcus faecalis

    International Nuclear Information System (INIS)

    Miehl, R.; Miller, M.; Yasbin, R.E.

    1980-01-01

    A 38.5-Mdal plasmid of Streptococcus faecalis subdp. zymogenes has been shown to enhance survival following uv irradiation. In addition, the presence of this plasmid increases the mutation frequencies following uv irradiation and enhanced W-reactivation. The data presented indicate that S. faecalis has an inducible error-prone repair system and that the plasmid enhances these repair functions

  11. Ultrastructural changes of photodegradation of wood surfaces exposed to UV

    International Nuclear Information System (INIS)

    Kuo, M.L.; Hu, N.

    1991-01-01

    Red pine sapwood transverse and radial surfaces were exposed to ultraviolet (UV) light for 3 to 40 days. Effect of UV irradiation on ultrastructural changes of cell walls were studied by scanning (SEM) and transmission (TEM) electron microscopy. SEM study of transverse sections showed that during initial stages of UV irradiation, lignin in cell corners and in the compound middle lamellae was preferentially degraded and that the radial middle lamellae substained a greater rate of UV degradation than did the tangential middle lamellae. Massive cell wall degradation, as indicated by cell wall thinning, did not occur until surfaces were exposed to UV light for more than 10 days. TEM study of radial cell wall surfaces indicated that lignin lining the warty layer was removed by UV irradiation in 3 days and that warts were destroyed by a UV irradiation in 7 days. UV irradiation of cell wall surfaces produced a substantial amount of water-soluble degradation products. After 30 days of UV irradiation, the S3 layer was totally removed and revealed the very fragile S2 layer. (author)

  12. The responses to supplementary of UV radiation of some temperate meadow species

    International Nuclear Information System (INIS)

    Cooley, N.M.

    2002-01-01

    Full text: The growth and development of various meadow species was monitored while growing under enhanced UV-radiation in the natural light environment. Growth responses to supplementary ultraviolet-B (UV-B+A) and ultraviolet-A (UV-A) were compared to the ambient daylight treatment for Bellis perennis, Cardamine pratensis, Cynosurus critatus and Ranunculus ficaria. When the response of ultraviolet A (UV-A) treated plants were compared with those of the UV-B+A, differences were found which varied according to the species and parameter investigated. To further understand the growth responses of the UV-A treatment and their relationship to the UV-B responses polychromatic action spectra in the natural environment was employed B perennis had an action maximum in the UV B (280-315 nm) while C cristatus demonstrates no action in the UV-B but action in the UV-A region (315-400 nm.). To enable further explanation of the effects of elevated UV radiation on the meadow plants Arabidopsis thaliana ecotypes and mutants were investigated. A thaliana ecotypes dry weight accumulation was found to respond differently to the UV treatments. UV B+A treatment was found to inhibit dry weight accumulation in most ecotypes. When UV B+A induced inhibition was expressed in terms of ambient growth rate for each ecotype a linear relationship could be derived. The higher the growth rate the more susceptible the ecotype was to UV-B+A inhibition. The pertinence of the UV-A treatment and UV protocol is discussed. It is suggested that UV responses could alter the diversity of the meadow equilibrium

  13. Delayed expression of enhanced reactivation and decreased mutagenesis of UV-irradiated adenovirus in UV-irradiated ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Bennett, C.B.; Rainbow, A.J.

    1988-01-01

    In this study the authors examined UV-enhanced reactivation (UVER) and UV-enhanced mutagenesis (UVEM) of UV-irradiated adenovirus in AT fibroblasts. UVER factors for Ad V antigen expression were significantly less than normal in AT strains tested when infection occurred immediately after UV-irradiation of cells. However, UVER factors were >1 and similar to those found for normal strains when cells were infected 24 h after UV-irradiation, indicating delay in the expression of UVER for Ad V antigen in AT cells. UV-irradiation of both normal and AT cells 24 h prior to infection also resulted in a significant increase in progeny survival for UV-irradiated Ad. In normal cells, this progeny UVER was concomitant with a significant increase in the mutation frequency for UV-irradiated virus (increase in targeted mutagenesis) suggesting existence of an inducible error-prone DNA repair mode in normal human cells. In contrast, pre-UV-irradiation of AT cells resulted in a significant decrease in the mutation frequency for UV-irradiated virus. (author)

  14. Lack of Physiological Depth Patterns in Conspecifics of Endemic Antarctic Brown Algae: A Trade-Off between UV Stress Tolerance and Shade Adaptation?

    Directory of Open Access Journals (Sweden)

    Iván Gómez

    Full Text Available A striking characteristic of endemic Antarctic brown algae is their broad vertical distribution. This feature is largely determined by the shade adaptation in order to cope with the seasonal variation in light availability. However, during spring-summer months, when light penetrates deep in the water column these organisms have to withstand high levels of solar radiation, including UV. In the present study we examine the light use characteristics in parallel to a potential for UV tolerance (measured as content of phenolic compounds, antioxidant activity and maximum quantum yield of fluorescence in conspecific populations of four Antarctic brown algae (Ascoseira mirabilis, Desmarestia menziesii, D. anceps and Himantothallus grandifolius distributed over a depth gradient between 5 and 30 m. The main results indicated that a photosynthetic efficiency was uniform along the depth gradient in all the studied species, and b short-term (6 h exposure to UV radiation revealed a high tolerance measured as chlorophyll fluorescence, phlorotannin content and antioxidant capacity. Multivariate analysis of similarity indicated that light requirements for photosynthesis, soluble phlorotannins and antioxidant capacity are the variables determining the responses along the depth gradient in all the studied species. The suite of physiological responses of algae with a shallower distribution (A. mirabilis and D. menziesii differed from those with deeper vertical range (D. anceps and H. grandifolius. These patterns are consistent with the underwater light penetration that defines two zones: 0-15 m, with influence of UV radiation (1% of UV-B and UV-A at 9 m and 15 m respectively and a zone below 15 m marked by PAR incidence (1% up to 30 m. These results support the prediction that algae show a UV stress tolerance capacity along a broad depth range according to their marked shade adaptation. The high contents of phlorotannins and antioxidant potential appear to be

  15. Enhanced charge transport and photovoltaic performance of PBDTTT-C-T/PC70BM solar cells via UV-ozone treatment.

    Science.gov (United States)

    Adhikary, Prajwal; Venkatesan, Swaminathan; Adhikari, Nirmal; Maharjan, Purna P; Adebanjo, Olusegun; Chen, Jihua; Qiao, Qiquan

    2013-10-21

    In this work, the electron transport layer of PBDTTT-C-T/PC70BM polymer solar cells were subjected to UV-ozone treatment, leading to improved cell performances from 6.46% to 8.34%. The solar cell efficiency reached a maximum of 8.34% after an optimal 5 minute UV-ozone treatment, and then decreased if treated for a longer time. To the best of our knowledge, the mechanism behind the effects of UV-ozone treatment on the improvement of charge transport and cell performance is not fully understood. We have developed a fundamental understanding of the UV-ozone treatment mechanism, which explains both the enhancements in charge transport and photovoltaic performance at an optimal treatment time, and also the phenomenon whereby further treatment time leads to a drop in cell efficiency. Transient photocurrent measurements indicated that the cell charge transport times were 1370 ns, 770 ns, 832 ns, 867 ns, and 1150 ns for the 0 min, 5 min, 10 min, 15 min, and 20 min UV-ozone treatment times, respectively. Therefore the 5 min UV-ozone treatment time led to the shortest transport time and the most efficient charge transport in the cells. The 5 min UV-ozone treated sample exhibited the highest peak intensity (E2) in the Raman spectra of the treated films, at about 437 cm(-1), indicating that it possessed the best wurtzite phase crystallinity of the ZnO films. Further increasing the UV-ozone treatment time from 5 to 20 min induced the formation of p-type defects (e.g. interstitial oxygen atoms), pushing the ZnO Fermi-level further away from the vacuum level, and decreasing the wurtzite crystallinity.

  16. UV-MAOR - UV-B-specific reactions of marine planktons. Final report

    International Nuclear Information System (INIS)

    Gerbersdorf, S.; Steeger, H.U.; Schubert, H.; Paul, R.J.

    2001-02-01

    An initial finding of the studies performed here is that under certain hydrogeographic and meteorological conditions vertical migration of phyto and zooplankton also occurs in near-shore parts of flat waters. The vertical migration of phytoplankton was induced by exceeding the threshold intensity of approx. 300 μmol photons m -2 s -1 (PAR). However, the sigmoidal course of the reaction of phytoplankton suggests that it is apparently not the PAR intensity alone but the ratio of PAR/UV-B which governs the downward migration. However, the present body of data is not sufficient for a definitive statistical verification of this finding. Light irradiation resulted in an increased density and thus in a reduced buoyancy of flounder spawn. This effect was primarily dependent on intensity and did not increase upon irradiation with UV-B, UV-A and PAR as compared to UV-A and PAR alone. Irradiation with UV-B did not influence the substance located in the vitellus whose absorption maximum was found to be 300 nm, probably gadusol

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

    Science.gov (United States)

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

    2007-03-01

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

  18. Comparison of UV-LED and low pressure UV for water disinfection: Photoreactivation and dark repair of Escherichia coli.

    Science.gov (United States)

    Li, Guo-Qiang; Wang, Wen-Long; Huo, Zheng-Yang; Lu, Yun; Hu, Hong-Ying

    2017-12-01

    Studies on ultraviolet light-emitting diode (UV-LED) water disinfection have shown advantages, such as safety, flexible design, and lower starting voltages. However, information about reactivation after UV-LED disinfection is limited, which is an important issue of UV light-based technology. In this study, the photoreactivation and dark repair of Escherichia coli after UV-LEDs and low pressure (LP) UV disinfection were compared. Four UV-LED units, 265 nm, 280 nm, the combination of 265 + 280 (50%), and 265 + 280 (75%) were tested. 265 nm LEDs was more effective than 280 nm LEDs and LP UV lamps for E. coli inactivation. No synergic effect for disinfection was observed from the combination of 265 and 280 nm LEDs. 265 nm LEDs had no different reactivation performances with that of LP UV, while 280 nm LEDs could significantly repress photoreactivation and dark repair at a low irradiation intensity of 6.9 mJ/cm 2 . Furthermore, the UV-induced damage of 280 nm LEDs was less repaired which was determined by endonuclease sensitive site (ESS) assay. The impaired protein activities by 280 nm LEDs might be one of the reasons that inhibited reactivation. A new reactivation rate constant, K max , was introduced into the logistic model to simulate the reactivation data, which showed positive relationship with the maximum survival ratio and was more reasonable to interpret the results of photoreactivation and dark repair. This study revealed the distinct roles of different UV lights in disinfection and reactivation, which is helpful for the future design of UV-LED equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Standardization of UV LED measurements

    Science.gov (United States)

    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.

  20. Health hazards of UV radiation

    International Nuclear Information System (INIS)

    Matthes, R.

    1994-01-01

    The author describes the effects and health risks of UV exposure. This includes UV effects on the DNS, the eyes, the immune system, and the skin. Finally, recommendations are given for protection against excessive UV exposure on the basis of the IRPA/INIRC guidelines. (orig.) [de

  1. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  2. Chemical and UV Mutagenesis.

    Science.gov (United States)

    Bose, Jeffrey L

    2016-01-01

    The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.

  3. UV curable materials development

    Energy Technology Data Exchange (ETDEWEB)

    Parker, B.G.

    1996-12-01

    Adhesives, coatings, and inks were selected for evaluation based on literature search and possible production applications. A differential photocalorimeter was used to measure degree of cure and allow prediction of optimum processing conditions. UV cure equipment were characterized and the ability to size equipment to specific materials cure needs established. Adhesion tests procedures were developed for the adhesives and solvent resistance testing procedures developed for the coatings and inks.

  4. UV-induced structural changes in chromatin

    International Nuclear Information System (INIS)

    Lang, H.; Zimmer, C.; Vengerov, Yu.Yu.

    1985-01-01

    UV-induced structural alterations of chromatin were studied by means of CD, electron microscopic, and gel electrophoretic measurements. The results indicate that chromatin undergoes serious structural changes after irradiation even at very low fluences. In the low fluence range the structural transitions from the higher ordered chromatin structure to the unfolded state occur without detectable changes in the content of histone H1 and of the core histones. Histone H1 disappears only at fluences above 10 kJ/m 2 . Furthermore, DNA in chromatin is much more sensitive against UV-irradiation and shows a higher degree of strand scission relative to free DNA. While fragmentation in free DNA occurs at fluences above 15 kJ/m 2 , it occurs even at 5.5 kJ/m 2 in the case of chromatin. The biological meaning of the observed UV-induced structural alterations of chromatin is discussed. (author)

  5. Wastewater disinfection with peracetic acid and UV

    International Nuclear Information System (INIS)

    Caretti, C.; Lubello, C.

    2001-01-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm - 2 is enough to meet the Italian limit [it

  6. UV Catalysis, Cyanotype Photography, and Sunscreens

    Science.gov (United States)

    Lawrence, Glen D.; Fishelson, Stuart

    1999-09-01

    This laboratory experiment is intended for a chemistry course for non-science majors. The experiment utilizes one of the earliest photographic processes, the cyanotype process, to demonstrate UV catalysis of chemical reactions. In addition to making photographic prints from negatives, the process can be used to test the effectiveness of sunscreens and the relative efficacy of the SPF (sun protection factor) rating of sunscreens. This is an inexpensive process, requiring solutions of ammonium ferric citrate and potassium ferricyanide, with options to use hydrogen peroxide and ammonium hydroxide solutions. Students can prepare their own UV-sensitized paper with the indicated chemicals and watch the photographic image appear as it is exposed to sunlight or fluorescent UV lamps in a light box designed for use in this experiment. The laboratory experiment should stimulate discussion of UV catalysis, photographic processes and photochemistry, sunscreens, and UV damage to biological organisms. The chemicals used are relatively nontoxic, and the procedure is simple enough to be used by groups of diverse ages and abilities.

  7. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    Energy Technology Data Exchange (ETDEWEB)

    Spiliotopoulou, Aikaterini [Water ApS, Farum Gydevej 64, 3520 Farum (Denmark); Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Hansen, Kamilla M.S., E-mail: kmsh@env.dtu.dk [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Andersen, Henrik R. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark)

    2015-07-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  8. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    International Nuclear Information System (INIS)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M.S.; Andersen, Henrik R.

    2015-01-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  9. Thermoluminescence sensitivity of ulexite after UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Topaksu, M., E-mail: mats@cu.edu.tr [Cukurova University, Arts-Sciences Faculty, Physics Department, 01330 Adana (Turkey); CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, (CSIC), C/José Gutiérrez Abascal 2, 28006 Madrid (Spain)

    2015-04-15

    Highlights: •UV-induced thermoluminescence emission of Turkish ulexite was studied. •There are three groups of components. •The UV exposures were performed at controlled temperatures. -- Abstract: The effects of UV radiation on the thermoluminescence (TL) properties of natural materials, in contrast to synthetic materials, have been scarcely studied. We report on the UV-induced thermoluminescence emission of a Turkish ulexite (NaCaB{sub 5}O{sub 6}(OH){sub 6}·5H{sub 2}O) that displays very complex TL glow curves, with at least three groups of components peaked at 130–140 °C, 240 °C and, 340 °C, wherein the last group is weaker. Such emission could be associated with structural changes in the lattice as well as alkali self-diffusion processes. The UV exposure performed at controlled temperatures (at room temperature (RT), 50 °C and 100 °C) produced a (i) different evolutions of the intensities of each maximum, which are directly related to the controlled thermal treatment; (ii) different intensity ratios among the groups of components; (iii) different activation energies (E{sub a}) (1.13 eV for RT, 0.99 eV for 50 °C and 0.49 eV for 100 °C) calculated using the initial rise method; and (iv) similar scattering values (12.4%, 8.2% and 12.8%), which were not a function of the controlled temperature. The thermal stability tests conducted on this borate at different temperatures, based on the T{sub stop} protocol, confirm the presence of a continuum in the distribution of the trap system with progressively increasing E{sub a} (from 0.60 to 0.90 eV)

  10. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

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

  11. Detection, fate and inactivation of pathogenic norovirus employing settlement and UV treatment in wastewater treatment facilities

    International Nuclear Information System (INIS)

    Barrett, M.; Fitzhenry, K.; O'Flaherty, V.; Dore, W.; Keaveney, S.; Cormican, M.; Rowan, N.; Clifford, E.

    2016-01-01

    It is accepted that discharged wastewaters can be a significant source of pathogenic viruses in receiving water bodies contributing to pollution and may in turn enter the human food chain and pose a risk to human health, thus norovirus (NoV) is often a predominant cause of gastroenteritis globally. Working with NoV poses particular challenges as it cannot be readily identified and detection by molecular methods does not assess infectivity. It has been proposed that the infectivity of NoV may be modelled through the use of an alternative virus; F-specific RNA (FRNA) bacteriophages; GA genotype and other FRNA bacteriophages have been used as a surrogate in studies of NoV inactivation. This study investigated the efficiency of novel pulsed ultraviolet irradiation and low pressure ultraviolet irradiation as a potential pathogen inactivation system for NoV and FRNA bacteriophage (GA) in secondary treated wastewaters. The role of UV dose and the impact of suspended solids concentration on removal efficiency were also examined. The study also investigated the role of settlement processes in wastewater treatment plants in removing NoV. While NoV inactivation could not be determined it was found that at a maximum UV dose of 6.9 J/cm"2 (6900 mJ/cm"2) an average 2.4 log removal of FRNA bacteriophage (GA) was observed; indicating the potential need for high UV doses to remove NoV if FRNA bacteriophage prove a suitable indicator for NoV. The study found that increasing concentrations of suspended solids impacted on PUV efficiency however, it appears the extent of the impact may be site specific. Furthermore, the study found that settlement processes can play a significant role in the removal of FRNA bacteriophage, thus potentially NoV. - Highlights: • Effectiveness of low pressure UV and novel high-intensity pulsed UV disinfection in NoVs removal. • Reduction of FRNA bacteriophage was seen in clarified wastewater after settling. • Adsorption of viral particles to solids

  12. Detection, fate and inactivation of pathogenic norovirus employing settlement and UV treatment in wastewater treatment facilities

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, M. [Microbial Ecology Laboratory, Microbiology, School of Natural sciences, National University of Ireland Galway (Ireland); Ryan Institute, National University of Ireland Galway (Ireland); College of Engineering and Informatics, National University of Ireland Galway (Ireland); Fitzhenry, K. [Ryan Institute, National University of Ireland Galway (Ireland); College of Engineering and Informatics, National University of Ireland Galway (Ireland); O' Flaherty, V. [Microbial Ecology Laboratory, Microbiology, School of Natural sciences, National University of Ireland Galway (Ireland); Ryan Institute, National University of Ireland Galway (Ireland); Dore, W.; Keaveney, S. [Marine Institute, Galway (Ireland); Cormican, M. [Ryan Institute, National University of Ireland Galway (Ireland); Centre for Health from Environment, Ryan Institute, National University of Ireland Galway (Ireland); Rowan, N. [Bioscience Research Institute, Athlone Institute of Technology (Ireland); Clifford, E., E-mail: eoghan.clifford@nuigalway.ie [Ryan Institute, National University of Ireland Galway (Ireland); College of Engineering and Informatics, National University of Ireland Galway (Ireland)

    2016-10-15

    It is accepted that discharged wastewaters can be a significant source of pathogenic viruses in receiving water bodies contributing to pollution and may in turn enter the human food chain and pose a risk to human health, thus norovirus (NoV) is often a predominant cause of gastroenteritis globally. Working with NoV poses particular challenges as it cannot be readily identified and detection by molecular methods does not assess infectivity. It has been proposed that the infectivity of NoV may be modelled through the use of an alternative virus; F-specific RNA (FRNA) bacteriophages; GA genotype and other FRNA bacteriophages have been used as a surrogate in studies of NoV inactivation. This study investigated the efficiency of novel pulsed ultraviolet irradiation and low pressure ultraviolet irradiation as a potential pathogen inactivation system for NoV and FRNA bacteriophage (GA) in secondary treated wastewaters. The role of UV dose and the impact of suspended solids concentration on removal efficiency were also examined. The study also investigated the role of settlement processes in wastewater treatment plants in removing NoV. While NoV inactivation could not be determined it was found that at a maximum UV dose of 6.9 J/cm{sup 2} (6900 mJ/cm{sup 2}) an average 2.4 log removal of FRNA bacteriophage (GA) was observed; indicating the potential need for high UV doses to remove NoV if FRNA bacteriophage prove a suitable indicator for NoV. The study found that increasing concentrations of suspended solids impacted on PUV efficiency however, it appears the extent of the impact may be site specific. Furthermore, the study found that settlement processes can play a significant role in the removal of FRNA bacteriophage, thus potentially NoV. - Highlights: • Effectiveness of low pressure UV and novel high-intensity pulsed UV disinfection in NoVs removal. • Reduction of FRNA bacteriophage was seen in clarified wastewater after settling. • Adsorption of viral particles

  13. Evaluating efficacy of filtration + UV-C radiation for ballast water treatment at different temperatures

    Science.gov (United States)

    Casas-Monroy, Oscar; Linley, Robert D.; Chan, Po-Shun; Kydd, Jocelyn; Vanden Byllaardt, Julie; Bailey, Sarah

    2018-03-01

    To prevent new ballast water-mediated introductions of aquatic nonindigenous species (NIS), many ships will soon use approved Ballast Water Management Systems (BWMS) to meet discharge standards for the maximum number of viable organisms in ballast water. Type approval testing of BWMS is typically conducted during warmer seasons when plankton concentrations are highest, despite the fact that ships operate globally year-round. Low temperatures encountered in polar and cool temperate climates, particularly during the winter season, may impact treatment efficacy through changes in plankton community composition, biological metabolic rates or chemical reaction rates. Filtration + UV irradiance is one of the most common ballast water treatment methods, but its effectiveness at low temperatures has not been assessed. The objective in this study was to examine the efficacy of filtration + UV-C irradiation treatment at low temperatures for removal or inactivation of phytoplankton and zooplankton populations during simulated ballast water treatment. Organisms from two size classes (≥ 10 to < 50 μm and ≥ 50 μm) were identified and enumerated using microscope and culture techniques. The response of organisms in both size categories to UV-C irradiation was evident across a range of temperatures (18 °C, 12 °C and 2 °C) as a significant decrease in concentration between controls and treated samples. Results indicate that filtration + UV-C irradiation will be effective at low temperatures, with few viable organisms ≥ 10 to < 50 μm recorded even 21 days following UV exposure (significantly lower than in the control treatment).

  14. Environment Canada's Children's UV Index Sun Awareness Programme

    International Nuclear Information System (INIS)

    Fergusson, A.

    2000-01-01

    In 1992, Canada introduced the UV Index forecast programme to increase public awareness of UV radiation, to support health agencies in educating the public about UV risks, and to assist individuals in making healthy lifestyle decisions. A national sun health survey in 1997 indicated that about half of adults reported taking extra precautions to protect themselves from the sun on days when the UV Index was rated 'high'. In response to this concern in 1998, Environment Canada produced an UN Index poster that was sent to 3000 elementary schools across Canada. The poster targeted children between the ages of 8 and 15 and provided information to minimise the risk to their health from solar UV radiation without spoiling their outdoor fun. Based on this experience Environment Canada produced in 1999, the Daily UV Index and Calendar Poster that was sent to 14,000 elementary schools across Canada. An UV Index website has been created to provide information to students and teachers on the science of UV radiation and the UV Index. (author)

  15. The genetic architecture of UV floral patterning in sunflower.

    Science.gov (United States)

    Moyers, Brook T; Owens, Gregory L; Baute, Gregory J; Rieseberg, Loren H

    2017-07-01

    The patterning of floral ultraviolet (UV) pigmentation varies both intra- and interspecifically in sunflowers and many other plant species, impacts pollinator attraction, and can be critical to reproductive success and crop yields. However, the genetic basis for variation in UV patterning is largely unknown. This study examines the genetic architecture for proportional and absolute size of the UV bullseye in Helianthus argophyllus , a close relative of the domesticated sunflower. A camera modified to capture UV light (320-380 nm) was used to phenotype floral UV patterning in an F 2 mapping population, then quantitative trait loci (QTL) were identified using genotyping-by-sequencing and linkage mapping. The ability of these QTL to predict the UV patterning of natural population individuals was also assessed. Proportional UV pigmentation is additively controlled by six moderate effect QTL that are predictive of this phenotype in natural populations. In contrast, UV bullseye size is controlled by a single large effect QTL that also controls flowerhead size and co-localizes with a major flowering time QTL in Helianthus . The co-localization of the UV bullseye size QTL, flowerhead size QTL and a previously known flowering time QTL may indicate a single highly pleiotropic locus or several closely linked loci, which could inhibit UV bullseye size from responding to selection without change in correlated characters. The genetic architecture of proportional UV pigmentation is relatively simple and different from that of UV bullseye size, and so should be able to respond to natural or artificial selection independently. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  16. uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

    Science.gov (United States)

    Chae, S K; Kafer, E

    1993-01-01

    Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

  17. Sinapate esters provide greater UV-B attenuation than flavonoids in Arabidopsis thaliana (Brassicaceae)

    International Nuclear Information System (INIS)

    Sheahan, J.J.

    1996-01-01

    Mutants affected in flavonoid (tt4) or sinapate ester (fah1) biosynthesis were used to assess the relative importance of these phenolic UV photoprotectants in Arabidopsis. Flavonoid and sinapate ester absorption was more specific for UV-B than major nonphenolic chromophores in crude extracts. A new method of evaluating phenolic UV-B attenuation was developed using fluorescence analysis. When excited by UV-B, sinapate ester containing leaves and cotyledons had enhanced sinapate ester fluorescence and reduced chlorophyll fluorescence relative to those without sinapate esters. Although fluorescence analysis gave no evidence of UV-B attenuation by flavonoids, enhanced chlorophyll and protein loss were observed upon UV-B exposure in flavonoid-deficient leaves, suggesting they have another mechanism of UV-B protection. The hydroxycinnamates have been largely ignored as UV-B attenuating pigments. and the results indicate that greater attention should be paid to their role in attenuating UV-B

  18. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

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

    2008-01-01

    on high-arctic vegetation. They supplement previous investigations from the Arctic focussing on other variables like growth etc., which have reported no or minor plant responses to UV-B, and clearly indicates that UV-B radiation is an important factor affecting plant life at high-arctic Zackenberg......Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high......-arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...

  19. UV ability to destroy poliovirus end FRNA specific bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J.; Joret, J.C.; Lesavre, J.; Perrot, J.Y.

    1996-01-01

    In France, the use of ultraviolet radiation to disinfect secondary effluents is only in its initial stage. The aim of this study was to examine the ability of UV to destroy Poliovirus Type 1 and FRNA specific bacteriophages (laboratory MS2 phages and indigenous phages). Concentrated viral solutions were mixed with secondary effluents artificially enriched with suspended solids and then irradiated at various UV dose in a collimated beam. Bacteriological analysis of Escherichia coli and enterococci were performed at the same time. UV were very efficient to kill Poliovirus : Inactivation of 3 and 5 log units were observed respectively at UV doses of 20 and 40 mW/cm{sup 2}. The Poliovirus disinfection rate was almost the same than Escherichia coli. Enterococci were more resistant than E. coli. Inactivation of MS2 bacteriophages was significantly correlated to UV dose following the relationship MS2 Inactivation = 0.047{sup *} Dose + 0,396. At UV dose of 20 mWs/cm{sup 2}, MS2 phages were 2.3 times more resistant to UV than Poliovirus, i.e. they need UV dose 2,3 times greater to be disinfected at the same level. A review of the literature has also shown that viruses more resistant to UV treatment have never been reported. All this would tend to confirm the interest of this group of virus as indicators of the disinfection efficiency of UV, which could indicate, on site, the inactivation of pathogenic viruses. Inactivation rates obtained for FRNA phages proved the good virucidal activity of UV. The inactivation of indigenous FRNA bacteriophages was not correlated with E. coli inactivation. On the other hand, it was correlated with enterococci inactivation. (Author). 23 refs., 7 figs., 4 tabs.

  20. Beneficial effects of enhanced UV-B radiation under field conditions: improvement of needle water relations and survival capacity of Pinus pinea L. seedlings during the dry Mediterranean summer

    International Nuclear Information System (INIS)

    Manetas, Y.; Petropoulou, Y.; Stamatakis, K.; Nikolopoulos, D.; Levizou, E.; Psaras, G.; Karabourniotis, G.

    1997-01-01

    The possible mechanism(s) by which supplemental UV-B radiation alleviates the adverse effects of summer drought in Mediterranean pines (Petropoulou et al. 1995) were investigated with seedlings of Pinus pinea. Plants received ambient or ambient plus supplemental UV-B radiation (biologically equivalent to a 15% ozone depletion over Patras, 38.3° N, 29.1° E) and natural precipitation or additional irrigation. Treatments started on 1 February, 1994 and lasted up to the end of the dry period (29 September). In well-watered plants, UV-B radiation had no influence on photosystem II photochemical efficiency and biomass accumulation. Water stressed plants suffered from needle loss and reduced photosystem II photochemical efficiency during the summer. These symptoms, however, were less pronounced in plants receiving supplemental UV-B radiation, resulting in higher total biomass at plant harvest. Laboratory tests showed that enhanced UV-B radiation did not improve the tolerance of photosystem II against drought, high light, high temperature and oxidative stress. Enhanced UV-B radiation, however, improved the water economy of water stressed plants, as judged by measurements of needle relative water content. In addition, it caused an almost two-fold increase of cuticle thickness. No such UV-B radiation effects were observed in well-watered pines. The results indicate that the combination of water stress and UV-B radiation may trigger specific responses, enabling the plants to avoid excessive water loss and, thereby, maintain a more efficient photosynthetic apparatus during the summer. The extent of this apparently positive UV-B radiation effect would depend on the amount of summer precipitation. Abbreviations: DW – dry weight, F v /F m – ratio of variable to maximum fluorescence, A 300 – absorbance at 300 nm, PAR – photosynthetically active radiation, PS II – photosystem II, RWC – relative water content, TCA – trichloroacetic acid, UV-B BE – biologically

  1. Type C virus activation in nontransformed mouse cells by uv-irradiated herpes simplex virus

    International Nuclear Information System (INIS)

    Hampar, B.; Hatanaka, M.; Aulakh, G.; Derge, J.G.; Lee, L.; Showalter, S.

    1977-01-01

    Infection of nontransformed mouse cells with uv-irradiated herpes simplex virus (uv-HSV) resulted in the activation of an endogenous xenotropic (x-tropic) type C virus. Synthesis of type C virus persisted for only a few days, with most of the virus remaining cell associated. The levels of type C virus activated by uv-HSV varied depending on the multiplicity of infection (m.o.i.) and the uv dose. At low uv doses, where cell killing occurred, little or no type C virus synthesis was observed. Maximum levels of type C virus synthesis were observed with the minimum uv dose which eliminated cell killing by HSV. Synthesis of type C virus, albeit at lower levels, was still observed at uv doses beyond those required to prevent cell killing

  2. Type C virus activation in nontransformed mouse cells by uv-irradiated herpes simplex virus

    Energy Technology Data Exchange (ETDEWEB)

    Hampar, B. (National Institutes of Health, Bethesda, MD); Hatanaka, M.; Aulakh, G.; Derge, J.G.; Lee, L.; Showalter, S.

    1977-02-01

    Infection of nontransformed mouse cells with uv-irradiated herpes simplex virus (uv-HSV) resulted in the activation of an endogenous xenotropic (x-tropic) type C virus. Synthesis of type C virus persisted for only a few days, with most of the virus remaining cell associated. The levels of type C virus activated by uv-HSV varied depending on the multiplicity of infection (m.o.i.) and the uv dose. At low uv doses, where cell killing occurred, little or no type C virus synthesis was observed. Maximum levels of type C virus synthesis were observed with the minimum uv dose which eliminated cell killing by HSV. Synthesis of type C virus, albeit at lower levels, was still observed at uv doses beyond those required to prevent cell killing.

  3. Semi-conservative synthesis of DNA in UV-sensitive mutant cells of Chinese hamster after UV-irradiation

    International Nuclear Information System (INIS)

    Vikhanskaya, F.L.; Khrebtukova, I.A.; Manuilova, E.S.

    1985-01-01

    A study was made of the rate of semi-conservative DNA synthesis in asynchronous UV-resistant (clone V79) and UV-sensitive clones (VII and XII) of Chinese hamster cells after UV-irradiation. In all 3 clones studied, UV-irradiation (5-30 J/m 2 ) induced a decrease in the rate of DNA synthesis during the subsequent 1-2 h. In the resistant clone (V79) recovery of DNA synthesis rate started after the first 2 h post-irradiation (5 J/m 2 ) and by the 3rd hour reached its maximum value, which constituted 70% of that observed in control, non-irradiated cells. The UV-sensitive mutant clones VII and XII showed no recovery in the rate of DNA synthesis during 6-7 h post-irradiation. The results obtained show that the survival of cells is correlated with the ability of DNA synthesis to recover after UV-irradiation in 3 clones studied. The observed recovery of UV-inhibited DNA synthesis in mutant clones may be due to certain defects in DNA repair. (orig.)

  4. Maximum Entropy in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Tseng

    2014-07-01

    Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.

  5. Uvs Nuur, Mongolia

    Science.gov (United States)

    2007-01-01

    The Uvs Nuur Basin in Mongolia and the Russian Federation is the northernmost of the enclosed basins of Central Asia. It takes its name from Uvs Nuur Lake, a large, shallow and very saline lake, very important for migrating birds. Inscribed as a UNESCO World Heritage Site in 2003, the site is made up of twelve protected areas representing major biomes of eastern Eurasia. The steppe ecosystem supports a rich diversity of birds and the desert is home to a number of rare gerbil, jerboas and the marbled polecat. The mountains are an important refuge for the endangered snow leopard, mountain sheep, and the Asiatic ibex. The image covers an area of 46 x 47.8 km, was acquired on September 4, 2001, and is located near 50.3 degrees north latitude, 90.7 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

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

    Science.gov (United States)

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

    2017-09-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 log 10 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 log 10 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. - Highlights: • As a disinfectant, chlorine is more effective than UV in inactivating Aspergillus flavus. • As a combined method, UV irradiation followed by chlorination shows high efficiency. • UV irradiation can improve effectiveness of chlorination in reducing Aspergillus flavus

  8. Comments on a Method to Measure Sucralose Using UV Photodegradation Followed by UV Spectrophotometry.

    Science.gov (United States)

    Fang, Te; Andrews, Susan A; Hofmann, Ron

    2017-05-01

    A simple and quick method to measure sucralose in aqueous solution at concentrations in the order of 0.1-1.2 g·L-1 proposed by Idris et al. uses UV irradiation prior to UV spectrophotometry. The photolysis of sucralose forms a photoactive compound characterized by maximum absorbance at approximately 270 nm. The conditions required for sucralose photolysis, however, had not been completely reported. In this work, the procedure described by Idris et al. was replicated using a low-pressure UV lamp to irradiate sucralose samples with a wider range of initial concentrations (0.04-10 g·L-1) with known fluences. It was determined that care must be taken to ensure that the same fluence is applied for both calibration and measurement steps because the absorbance of the sucralose photolysis product is a function of the applied fluence. The way the samples are irradiated also has an impact on the results in that the method exhibits a greater linear range if an apparatus is used that maximizes the fluence rate (e.g., by placing samples closer to the UV source or using a higher-intensity lamp).

  9. Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

    OpenAIRE

    Beber de Souza, Jeanette; Queiroz Valdez, Fernanda; Jeranoski, Rhuan Felipe; Vidal, Carlos Magno de Sousa; Cavallini, Grasiele Soares

    2015-01-01

    The individual methods of disinfection peracetic acid (PAA) and UV radiation and combined process PAA/UV in water (synthetic) and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater), and coliphages (such as virus indicators). Under the experimental conditions investigated, doses o...

  10. The precipitation synthesis of broad-spectrum UV absorber nanoceria

    International Nuclear Information System (INIS)

    Nurhasanah, Iis; Sutanto, Heri; Puspaningrum, Nurul Wahyu

    2013-01-01

    In this paper the possibility of nanoceria as broad-spectrum UV absorber was evaluated. Nanoceria were synthesized by precipitation process from cerium nitrate solution and ammonium hydroxide as precipitant agent. Isopropanol was mixed with water as solvent to prevent hard agglomeration. The structure of resulting nanoceria was characterized by x-ray diffractometer (XRD). The transparency in the visible light and efficiency of protection in UV A region were studied using ultraviolet-visible (UV - Vis) spectrophotometer. The results show that nanoceria possess good tranparency in visible light and high UV light absorption. The critical absorption wavelenght of 368 nm was obtained which is desirable for excellent broad-spectrum protection absorbers. Moreover, analysis of photodegradation nanoceria to methylene blue solution shows poor photocatalytic activity. It indicates that nanoceria suitable for used as UV absorber in personal care products

  11. UV-induced carbon monoxide emission from living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2013-01-01

    The global burden of carbon monoxide (CO) is rather uncertain. In this paper we address the potential for UV-induced CO emission by living terrestrial vegetation surfaces. Real-time measurements of CO concentrations were made with a cavity enhanced laser spectrometer connected in closed loop...... to either an ecosystem chamber or a plant-leaf scale chamber. Leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation as well as the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature......, indicating an abiotic process. The emission of CO in response to the UV-component of natural solar radiation was also evident at the ecosystem scale....

  12. Antibodies to UV irradiated DNA: the monitoring of DNA damage by ELISA and indirect immunofluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Wani, A A; Gibson-D' Ambrosio, R E; D' Ambrosio, S M [Ohio State Univ., Columbus (USA). Dept. of Radiology

    1984-10-01

    The enzyme-linked immunosorbant assay (ELISA) was modified to (1) characterize antibodies raised in rabbits against UV-irradiated single-stranded DNA (UVssDNA) complexed with methylated BSA and (2) directly detect pyrimidine dimers in irradiated DNA. The antisera specifically bound to UVssDNA, UVpoly(dT) and to a limited extent to UVdsDNA and UVpoly(dC). Fifty per cent of the maximum antibody binding was observed at a 1-5000 dilution against UVssDNA. Binding to ssDNA and poly(dT) was observed only at much higher concentrations of antibody, whereas no binding to double stranded DNA (dsDNA) was observed. The extent of binding of the antibody was dependent on the UV dose to DNA and the concentration of antigen immobilized on the plate. The ability of various irradiated molecules, DNA, homopolymers and linkers to act as inhibitors of antibody binding establishes that the antigenic determinants are mainly thymine homodimers with lower affinity for cytosine dimers. Potential usefulness of the antibodies to directly quantitate pyrimidine dimers in cells exposed to UV radiation was determined by indirect immunofluorescence. Flow cytometric analysis of immunostained human lymphocytes irradiated with 254 nm radiation indicated that greater than 50% of the population had significantly higher fluorescent intensity than unirradiated cells.

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

    Science.gov (United States)

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

    2016-03-01

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

  14. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    60, No. 3. — journal of. March 2003 physics pp. 415–422. Maximum stellar iron core mass. F W GIACOBBE. Chicago Research Center/American Air Liquide ... iron core compression due to the weight of non-ferrous matter overlying the iron cores within large .... thermal equilibrium velocities will tend to be non-relativistic.

  15. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs

  16. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore

  17. A portable storage maximum thermometer

    International Nuclear Information System (INIS)

    Fayart, Gerard.

    1976-01-01

    A clinical thermometer storing the voltage corresponding to the maximum temperature in an analog memory is described. End of the measurement is shown by a lamp switch out. The measurement time is shortened by means of a low thermal inertia platinum probe. This portable thermometer is fitted with cell test and calibration system [fr

  18. Neutron spectra unfolding with maximum entropy and maximum likelihood

    International Nuclear Information System (INIS)

    Itoh, Shikoh; Tsunoda, Toshiharu

    1989-01-01

    A new unfolding theory has been established on the basis of the maximum entropy principle and the maximum likelihood method. This theory correctly embodies the Poisson statistics of neutron detection, and always brings a positive solution over the whole energy range. Moreover, the theory unifies both problems of overdetermined and of underdetermined. For the latter, the ambiguity in assigning a prior probability, i.e. the initial guess in the Bayesian sense, has become extinct by virtue of the principle. An approximate expression of the covariance matrix for the resultant spectra is also presented. An efficient algorithm to solve the nonlinear system, which appears in the present study, has been established. Results of computer simulation showed the effectiveness of the present theory. (author)

  19. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita

    2016-03-01

    Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

  20. Postirradiation properties of a UV-sensitive variant of CHO

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.D.; de Veciana, M.; Presson-Tincknell, B. (California Univ., Berkeley (USA). Lawrence Berkeley Lab.)

    1982-08-01

    A UV-hypersensitive mutant of Chinese hamster ovary (CHO) cells, termed 43-3B, has been used in a comparative study with the wild type CHO in order to determine the involvement of repair in several postirradiation phenomena. 43-3B has the same growth rate and chromosome number as the wild type CHO-9. It is hypersensitive to UV irradiation. 43-3B shows only about 17% of the UV-stimulated unscheduled DNA repair synthesis of CHO-9 as measured by autoradiography. When breaks in supercoiled chromatin are measured after UV by the nucleoid sedimentation method, the mutant appears to be capable of carrying out only limited incision. A much reduced ability to recover control rates of semiconservative DNA synthesis after UV irradiation was observed in the repair-deficient 43-3B cell line, suggesting that the removal of UV-induced replication blocks by excision repair is the most important factor in allowing recovery of UV-inhibited DNA synthesis. Recovery of colony-forming ability between fractionated UV exposures was observed in the wild type CHO-9, but little recovery was seen in 43-3B. This indicates that excision repair capability can also be important in split-fluence recovery.

  1. Loss of photoreversibility for UV mutation in E. coli using 405 nm or near-UV challenge

    International Nuclear Information System (INIS)

    Kristoff, S.; Bockrath, R.

    1983-01-01

    E. coli mutagenized with germicidal ultraviolet light (UV) were incubated to allow for development of mutation-fixation processes. Fixation was estimated from the effects on mutation frequency of photoreactivation challenge during the first 60 min post-UV. Two different light sources were used for photoreactivation, one providing effective light primarily at 405 nm and another providing a broad range of near-UV around 365 nm. Kinetics for the loss of photoreversibility (LOP) were determined. The times for completion of LOP in wild-type cells indicated one fixation process for back mutation and another for de novo or converted suppressor mutation regardless of the light source. Using 405-nm light for photoreactivation, the LOP kinetics for back mutation and de novo suppressor mutation in uvrA cells were similar. Hence, classical observations were confirmed here. Immediately post-UV all mutation frequencies were more sensitive to near-UV than 405-nm light. (orig./AJ)

  2. Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

    Directory of Open Access Journals (Sweden)

    Jeanette Beber de Souza

    2015-01-01

    Full Text Available The individual methods of disinfection peracetic acid (PAA and UV radiation and combined process PAA/UV in water (synthetic and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater, and coliphages (such as virus indicators. Under the experimental conditions investigated, doses of 2, 3, and 4 mg/L of PAA and contact time of 10 minutes and 60 and 90 s exposure to UV radiation, the results indicated that the combined method PAA/UV provided superior efficacy when compared to individual methods of disinfection.

  3. UV imaging in pharmaceutical analysis

    DEFF Research Database (Denmark)

    Østergaard, Jesper

    2018-01-01

    UV imaging provides spatially and temporally resolved absorbance measurements, which are highly useful in pharmaceutical analysis. Commercial UV imaging instrumentation was originally developed as a detector for separation sciences, but the main use is in the area of in vitro dissolution...

  4. Development of a low cost UV index datalogger and comparison between UV index sensors

    Science.gov (United States)

    Gomes, L. M.; Ventura, L.

    2018-02-01

    Ultraviolet radiation (UVR) is the part of radiation emitted by the Sun, with range between 280 nm and 400 nm, and that reaches the Earth's surface. The UV rays are essential to the human because it stimulates the production of vitamin D but this radiation may be related to several health problems, including skin cancer and ocular diseases like pterygium, photokeratitis, cataract and more. To inform people about UV radiation, it is adopted the Ultraviolet Index (UVI). This UVI consists in a measure of solar UV radiation level, which contributes to cause sunburn on skin, also known as Erythema, and is indicated as an integer number between 1 and 14, associated to categories from low to extreme respectively. The aim of this work was to develop a low cost UVI datalogger capable of measuring three different UVI sensors simultaneously, record their data with timestamp and serve the measures online through a dedicated server, so general public can access their data and see the current UV radiation conditions. We also compared three different UVI sensors (SGlux UV cosine, Skye SKU440 and SiLabs SI1145) between them and with meteorological models during a period of months to verify their compliance. With five months data, we could verify the sensors working characteristics and decide which among them are the most suitable for research purposes.

  5. Photostability of cosmetic UV filters on mammalian skin under UV exposure.

    Science.gov (United States)

    Stiefel, Constanze; Schwack, Wolfgang; Nguyen, Yen-Thi Hai

    2015-01-01

    Previous studies showed that the common UV filter substances benzophenone-3 (BP-3), butyl methoxydibenzoylmethane (BM-DBM), octocrylene (OCR), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (EHS) and ethylhexyl triazone (EHT) were able to react with amino side chains of different proteins in vitro. To transfer the results to mammalian skin conditions, sunscreen products were applied on both prepared fresh porcine skin and glass plates, followed by UV irradiation and the determination of depletion of the respective UV filters. Significantly lower recoveries of the UV filters extracted from skin samples than from glass plates indicated the additional reaction of the UV filters with skin constituents, when proteins will be the most important reactants. Among the products tested, BP-3 showed the greatest differences in recoveries between glass and skin samples of about 13% and 24% after 2 and 4 h of irradiation, respectively, followed by EHS > BM-DBM > OCR > EHMC > EHT. The obtained results raise the question, whether the common in vitro evaluations of sunscreens, using inert substrate materials like roughened quartz or polymethyl methacrylate (PMMA) plates are really suitable to fully replace in vivo methods, as they cannot include skin-typical reactions. © 2014 The American Society of Photobiology.

  6. Environmental occurrence and distribution of organic UV stabilizers and UV filters in the sediment of Chinese Bohai and Yellow Seas.

    Science.gov (United States)

    Apel, Christina; Tang, Jianhui; Ebinghaus, Ralf

    2018-04-01

    Organic UV stabilizers and UV filters are applied to industrial materials and cosmetics worldwide. In plastics they prevent photo-induced degradation, while in cosmetics they protect human skin against harmful effects of UV radiation. This study reports on the occurrence and distribution of organic UV stabilizers and UV filters in the surface sediment of the Chinese Bohai and Yellow Seas for the first time. In total, 16 out of 21 analyzed substances were positively detected. Concentrations ranged from sub-ng/g dw to low ng/g dw. The highest concentration of 25 ng/g dw was found for octocrylene (OC) in the Laizhou Bay. In the study area, characteristic composition profiles could be identified. In Korea Bay, the dominating substances were OC and ethylhexyl salicylate (EHS). All other analytes were below their method quantification limit (MQL). Around the Shandong Peninsula, highest concentrations of benzotriazole derivatives were observed in this study with octrizole (UV-329) as the predominant compound, reaching concentrations of 6.09 ng/g dw. The distribution pattern of UV-329 and bumetrizole (UV-326) were related (Pearson correlation coefficient r > 0.98, p « 0.01 around the Shandong Peninsula), indicating an identical input pathway and similar environmental behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Color tuning of photonic gel films by UV irradiation

    Science.gov (United States)

    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.

  8. On Maximum Entropy and Inference

    Directory of Open Access Journals (Sweden)

    Luigi Gresele

    2017-11-01

    Full Text Available Maximum entropy is a powerful concept that entails a sharp separation between relevant and irrelevant variables. It is typically invoked in inference, once an assumption is made on what the relevant variables are, in order to estimate a model from data, that affords predictions on all other (dependent variables. Conversely, maximum entropy can be invoked to retrieve the relevant variables (sufficient statistics directly from the data, once a model is identified by Bayesian model selection. We explore this approach in the case of spin models with interactions of arbitrary order, and we discuss how relevant interactions can be inferred. In this perspective, the dimensionality of the inference problem is not set by the number of parameters in the model, but by the frequency distribution of the data. We illustrate the method showing its ability to recover the correct model in a few prototype cases and discuss its application on a real dataset.

  9. Maximum Water Hammer Sensitivity Analysis

    OpenAIRE

    Jalil Emadi; Abbas Solemani

    2011-01-01

    Pressure waves and Water Hammer occur in a pumping system when valves are closed or opened suddenly or in the case of sudden failure of pumps. Determination of maximum water hammer is considered one of the most important technical and economical items of which engineers and designers of pumping stations and conveyance pipelines should take care. Hammer Software is a recent application used to simulate water hammer. The present study focuses on determining significance of ...

  10. Maximum Gene-Support Tree

    Directory of Open Access Journals (Sweden)

    Yunfeng Shan

    2008-01-01

    Full Text Available Genomes and genes diversify during evolution; however, it is unclear to what extent genes still retain the relationship among species. Model species for molecular phylogenetic studies include yeasts and viruses whose genomes were sequenced as well as plants that have the fossil-supported true phylogenetic trees available. In this study, we generated single gene trees of seven yeast species as well as single gene trees of nine baculovirus species using all the orthologous genes among the species compared. Homologous genes among seven known plants were used for validation of the finding. Four algorithms—maximum parsimony (MP, minimum evolution (ME, maximum likelihood (ML, and neighbor-joining (NJ—were used. Trees were reconstructed before and after weighting the DNA and protein sequence lengths among genes. Rarely a gene can always generate the “true tree” by all the four algorithms. However, the most frequent gene tree, termed “maximum gene-support tree” (MGS tree, or WMGS tree for the weighted one, in yeasts, baculoviruses, or plants was consistently found to be the “true tree” among the species. The results provide insights into the overall degree of divergence of orthologous genes of the genomes analyzed and suggest the following: 1 The true tree relationship among the species studied is still maintained by the largest group of orthologous genes; 2 There are usually more orthologous genes with higher similarities between genetically closer species than between genetically more distant ones; and 3 The maximum gene-support tree reflects the phylogenetic relationship among species in comparison.

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

    Science.gov (United States)

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

    2016-11-01

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

  12. The Norwegian UV-monitoring program. Period 1995/96 to 2001

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Bjoern; Mikkelborg, Oddbjoern; Hannevik, Merete; Nilsen, Lill Tove; Saxeboel, Gunnar; Blaasaas, Karl Gerhard

    2002-07-01

    The report describes the program and results obtained during the period 1995 to 2001. The UV monitoring is performed at 8 locations between 58 {sup o} N and 79 {sup o} N. The experiments with the network implementation and operation are very good. Calibrations are traceable to several European UV networks, through the Nordic Intercomparison of UV and total ozone instruments in Sweden 2000. The measurements have been validated and found consistent. Six years of complete series of daily integrated erythemally effective UV-radiation (denoted UV-doses for short) and UV-indices are available for public and scientific use. The measurement series are yet too short to infer any trend in the UV-radiation. The Norwegian Institute provides UV-forecasts for air research (Author)

  13. LCLS Maximum Credible Beam Power

    International Nuclear Information System (INIS)

    Clendenin, J.

    2005-01-01

    The maximum credible beam power is defined as the highest credible average beam power that the accelerator can deliver to the point in question, given the laws of physics, the beam line design, and assuming all protection devices have failed. For a new accelerator project, the official maximum credible beam power is determined by project staff in consultation with the Radiation Physics Department, after examining the arguments and evidence presented by the appropriate accelerator physicist(s) and beam line engineers. The definitive parameter becomes part of the project's safety envelope. This technical note will first review the studies that were done for the Gun Test Facility (GTF) at SSRL, where a photoinjector similar to the one proposed for the LCLS is being tested. In Section 3 the maximum charge out of the gun for a single rf pulse is calculated. In Section 4, PARMELA simulations are used to track the beam from the gun to the end of the photoinjector. Finally in Section 5 the beam through the matching section and injected into Linac-1 is discussed

  14. The mechanisms of UV mutagenesis

    International Nuclear Information System (INIS)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

    Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: ''error-free'' bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases-the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation. (author)

  15. Deep UV LEDs

    Science.gov (United States)

    Han, Jung; Amano, Hiroshi; Schowalter, Leo

    2014-06-01

    Deep ultraviolet (DUV) photons interact strongly with a broad range of chemical and biological molecules; compact DUV light sources could enable a wide range of applications in chemi/bio-sensing, sterilization, agriculture, and industrial curing. The much shorter wavelength also results in useful characteristics related to optical diffraction (for lithography) and scattering (non-line-of-sight communication). The family of III-N (AlGaInN) compound semiconductors offers a tunable energy gap from infrared to DUV. While InGaN-based blue light emitters have been the primary focus for the obvious application of solid state lighting, there is a growing interest in the development of efficient UV and DUV light-emitting devices. In the past few years we have witnessed an increasing investment from both government and industry sectors to further the state of DUV light-emitting devices. The contributions in Semiconductor Science and Technology 's special issue on DUV devices provide an up-to-date snapshot covering many relevant topics in this field. Given the expected importance of bulk AlN substrate in DUV technology, we are pleased to include a review article by Hartmann et al on the growth of AlN bulk crystal by physical vapour transport. The issue of polarization field within the deep ultraviolet LEDs is examined in the article by Braut et al. Several commercial companies provide useful updates in their development of DUV emitters, including Nichia (Fujioka et al ), Nitride Semiconductors (Muramoto et al ) and Sensor Electronic Technology (Shatalov et al ). We believe these articles will provide an excellent overview of the state of technology. The growth of AlGaN heterostructures by molecular beam epitaxy, in contrast to the common organo-metallic vapour phase epitaxy, is discussed by Ivanov et al. Since hexagonal boron nitride (BN) has received much attention as both a UV and a two-dimensional electronic material, we believe it serves readers well to include the

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

    Science.gov (United States)

    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

  17. Improving radiochromic film's sensitivity by wrapping it with UV phosphor

    International Nuclear Information System (INIS)

    Geso, Moshi; Ackerly, Trevor; Patterson, William

    2004-01-01

    The main advantage of radiochromic-film dosimeters is the coupling of rapid full planar-acquisition, high-spatial resolution and dose linearity. Their main limitation, however, is their low radiation sensitivity. This precludes their application to measuring doses below a few Gy. Radiochromic films are sensitive to ultraviolet radiation. In this note the results of exposing radiochromic films to x rays through an UV imaging cassette, which converts and amplifies x rays to UV radiation, are presented. These results indicate a clear increase (around 50%) in radiochromic film's sensitivity to MV x rays (6, 10, and 18 MV) when exposed through the UV phosphor

  18. Observations of Halley's Comet by the Solar Maximum Mission (SMM)

    Science.gov (United States)

    Niedner, M. B.

    1986-01-01

    Solar Maximum Mission coronagraph/polarimeter observations of large scale phenomena in Halley's Comet are discussed. Observations of the hydrogen coma with the UV spectrometer are considered. It is concluded that coronograph/polarimeter observations of the disconnection event, in which the entire plasma tail uproots itself from the head of the comet, is convected away in the solar wind at speeds in the 50 to 100 km/sec range (relative to the head), and is replaced by a plasma tail constructed from folding ion-tail rays, are the most interesting.

  19. Implementation of UV-based advanced oxidation processes in algal medium recycling.

    Science.gov (United States)

    Wang, Wenxuan; Sha, Jun; Lu, Zhiying; Shao, Senlin; Sun, Peizhe; Hu, Qiang; Zhang, Xuezhi

    2018-09-01

    Algae show great potential as sustainable feedstock for numerous bioproducts. However, large volume of water consumption during algal biomass production makes that the culture media recycling is a necessity due to economic and environmental concern. To avoid the negative effect of enriched organic matters in the harvested culture media, pre-treatment prior to medium replenishment and reuse is required. In this study, degradation of algenitic organic matters (AOM) in the culture media by UV-based photolysis processes (i.e., direct UV, UV/peroxydisulfate (PDS), UV/H 2 O 2 , and UV/NH 2 Cl) was explored. The results showed that UV, UV/PDS, UV/H 2 O 2 and UV/NH 2 Cl caused a decrease of SUVA for 29.9%, 35.4%, 40.45%, and 22.6%, respectively, though the organic matter was almost not mineralized. Fluorescence excitation-emission matrix combined with parallel factor analysis indicated that UV/PDS and UV/H 2 O 2 degraded 47.26%-56.31% of the fulvic-like and humic-like fractions in AOM. Powder activated carbon absorption and growth evaluation for the AOPs-treated media indicated that UV/PDS and UV/H 2 O 2 processes not only could remove the growth inhibitors in the media, but were also beneficial to the algae growth. These results suggested that UV/PDS and UV/H 2 O 2 could effectively degrade the hydrophobic components in AOM and converted the growth inhibition fraction of AOM in the recycled media into nutrient source for algal growth. Different from the general application of UV-based AOP in the wastewater treatment, this study provided an innovative idea about how to pre-treat AOM in the media recycling: utilization rather than removal, which was a more sustainable and environment-friendly technology. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. UV-B Perception and Acclimation in Chlamydomonas reinhardtii[OPEN

    Science.gov (United States)

    Chappuis, Richard; Allorent, Guillaume

    2016-01-01

    Plants perceive UV-B, an intrinsic component of sunlight, via a signaling pathway that is mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8) and induces UV-B acclimation. To test whether similar UV-B perception mechanisms exist in the evolutionarily distant green alga Chlamydomonas reinhardtii, we identified Chlamydomonas orthologs of UVR8 and the key signaling factor CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). Cr-UVR8 shares sequence and structural similarity to Arabidopsis thaliana UVR8, has conserved tryptophan residues for UV-B photoreception, monomerizes upon UV-B exposure, and interacts with Cr-COP1 in a UV-B-dependent manner. Moreover, Cr-UVR8 can interact with At-COP1 and complement the Arabidopsis uvr8 mutant, demonstrating that it is a functional UV-B photoreceptor. Chlamydomonas shows apparent UV-B acclimation in colony survival and photosynthetic efficiency assays. UV-B exposure, at low levels that induce acclimation, led to broad changes in the Chlamydomonas transcriptome, including in genes related to photosynthesis. Impaired UV-B-induced activation in the Cr-COP1 mutant hit1 indicates that UVR8-COP1 signaling induces transcriptome changes in response to UV-B. Also, hit1 mutants are impaired in UV-B acclimation. Chlamydomonas UV-B acclimation preserved the photosystem II core proteins D1 and D2 under UV-B stress, which mitigated UV-B-induced photoinhibition. These findings highlight the early evolution of UVR8 photoreceptor signaling in the green lineage to induce UV-B acclimation and protection. PMID:27020958

  1. Combined treatment of hydroxypropyl guar gum in oilfield fracturing wastewater by coagulation and the UV/H2O2/ferrioxalate complexes process.

    Science.gov (United States)

    Zhang, Zhenchao

    2018-02-01

    Hydroxypropyl guar gum is considered to be a main component of oilfield fracturing wastewater (OFW). This work is intended to optimize the experimental conditions for the maximum oxidative degradation of hydroxypropyl guar gum by the coagulation and UV/H 2 O 2 /ferrioxalate complexes process. Optimal reaction conditions were proposed based on the chemical oxygen demand (COD) removal efficiency and UV _ vis spectra analysis. The overall removal efficiency of COD reached 83.8% for a dilution ratio of raw wastewater of 1:2, pH of 4 and FeCl 3 loading of 1,000 mg/L in the coagulation process; the dosage of H 2 O 2 (30%,v/v) was 0.6% (v/v) and added in three steps, the n(H 2 O 2 )/n(Fe 2+ ) was 2:1, n(Fe 2+ )/n(C 2 O 4 2- ) was 3:1 and pH was 4 in the UV/H 2 O 2 /ferrioxalate complexes process; pH was adjusted to 8.5-9 by NaOH and then cationic polyacrylamide (CPAM) of 2 mg/L was added in the neutralization and flocculation process. The decrease in COD during the coagulation process reduced the required H 2 O 2 dosage and improved efficiency in the subsequent UV/H 2 O 2 /ferrioxalate complexes process. Furthermore, COD removal efficiency significantly increased by more than 13.4% with the introduction of oxalate compared with UV/Fenton. The UV _ vis spectra analysis results indicated that the coagulation and UV/H 2 O 2 /ferrioxalate complexes process could efficiently remove the hydroxypropyl guar gum dissolved in OFW. An optimal combination of these parameters produced treated wastewater that met the GB8978-1996 Integrated Wastewater Discharge Standard level III emission standard.

  2. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  3. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

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

  4. UV-induced skin damage

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  5. Respiration shutoff in Escherichia coli after far-uv irradiation

    International Nuclear Information System (INIS)

    Swenson, P.A.; Norton, I.L.

    1984-01-01

    Damage to DNA of Escherichia coli by uv, ionizing radiation and chemicals causes a number of responses that require the recA + and lexA + gene products. The responses include error prone repair (as indicated by mutagenesis), filamentation and induction of prophage lambda. Another important rec/lex response, shutoff of respiration, which occurs 60 min after exposure to uv, is studied. Objective is to understand the genetic and biochemical bases of the shutoff process and its control

  6. Flare activity on UV Ceti: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-01-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  7. Flare activity on UV CETI: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-06-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  8. Upper limits for absorption by water vapor in the near-UV

    International Nuclear Information System (INIS)

    Wilson, Eoin M.; Wenger, John C.; Venables, Dean S.

    2016-01-01

    There are few experimental measurements of absorption by water vapor in the near-UV. Here we report the results of spectral measurements of water vapor absorption at ambient temperature and pressure from 325 nm to 420 nm, covering most tropospherically relevant short wavelengths. Spectra were recorded using a broadband optical cavity in the chemically controlled environment of an atmospheric simulation chamber. No absorption attributable to the water monomer (or the dimer) was observed at the 0.5 nm resolution of our system. Our results are consistent with calculated spectra and recent DOAS field observations, but contradict a report of significant water absorption in the near-UV. Based on the detection limit of our instrument, we report upper limits for the water absorption cross section of less than 5×10 −26 cm 2 molecule −1 at our instrument resolution. For a typical, indicative slant column density of 4×10 23 cm 2 , we calculate a maximum optical depth of 0.02 arising from absorption of water vapor in the atmosphere at wavelengths between 340 nm and 420 nm, with slightly higher maximum optical depths below 340 nm. The results of this work, together with recent atmospheric observations and computational results, suggest that water vapor absorption across most of the near-UV is small compared to visible and infrared wavelengths. - Highlights: • The absorption cross section of water vapor was studied from 325 to 420 nm. • The upper limit was 5×10 −26 cm 2 molecule −1 above 340 nm at 0.5 nm resolution. • Our result contradicts a recent report of appreciable absorption by water vapor.

  9. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    DEFF Research Database (Denmark)

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

    2008-01-01

    ). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower...... during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis...... on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B....

  10. Generic maximum likely scale selection

    DEFF Research Database (Denmark)

    Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo

    2007-01-01

    in this work is on applying this selection principle under a Brownian image model. This image model provides a simple scale invariant prior for natural images and we provide illustrative examples of the behavior of our scale estimation on such images. In these illustrative examples, estimation is based......The fundamental problem of local scale selection is addressed by means of a novel principle, which is based on maximum likelihood estimation. The principle is generally applicable to a broad variety of image models and descriptors, and provides a generic scale estimation methodology. The focus...

  11. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  12. Extreme Maximum Land Surface Temperatures.

    Science.gov (United States)

    Garratt, J. R.

    1992-09-01

    There are numerous reports in the literature of observations of land surface temperatures. Some of these, almost all made in situ, reveal maximum values in the 50°-70°C range, with a few, made in desert regions, near 80°C. Consideration of a simplified form of the surface energy balance equation, utilizing likely upper values of absorbed shortwave flux (1000 W m2) and screen air temperature (55°C), that surface temperatures in the vicinity of 90°-100°C may occur for dry, darkish soils of low thermal conductivity (0.1-0.2 W m1 K1). Numerical simulations confirm this and suggest that temperature gradients in the first few centimeters of soil may reach 0.5°-1°C mm1 under these extreme conditions. The study bears upon the intrinsic interest of identifying extreme maximum temperatures and yields interesting information regarding the comfort zone of animals (including man).

  13. On the maximum drawdown during speculative bubbles

    Science.gov (United States)

    Rotundo, Giulia; Navarra, Mauro

    2007-08-01

    A taxonomy of large financial crashes proposed in the literature locates the burst of speculative bubbles due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the bulk of drawdown price movement distribution. This paper goes on deeper in the analysis providing a further characterization of the rising part of such selected bubbles through the examination of drawdown and maximum drawdown movement of indices prices. The analysis of drawdown duration is also performed and it is the core of the risk measure estimated here.

  14. Maximum a posteriori decoder for digital communications

    Science.gov (United States)

    Altes, Richard A. (Inventor)

    1997-01-01

    A system and method for decoding by identification of the most likely phase coded signal corresponding to received data. The present invention has particular application to communication with signals that experience spurious random phase perturbations. The generalized estimator-correlator uses a maximum a posteriori (MAP) estimator to generate phase estimates for correlation with incoming data samples and for correlation with mean phases indicative of unique hypothesized signals. The result is a MAP likelihood statistic for each hypothesized transmission, wherein the highest value statistic identifies the transmitted signal.

  15. UV absorption and photoisomerization of p-methoxycinnamate grafted silicone.

    Science.gov (United States)

    Pattanaargson, Supason; Hongchinnagorn, Nantawan; Hirunsupachot, Piyawan; Sritana-anant, Yongsak

    2004-01-01

    p-Methoxycinnamate moieties, UV-B-absorptive chromophores of the widely used UV-B filter, 2-ethylhexyl p-methoxycinnamate (OMC), were grafted onto the 7 mol% amino functionalized silicone polymer through amide linkages. Comparing with OMC, the resulting poly [3-(p-methoxycinnamido)(propyl)(methyl)-dimethyl] siloxane copolymer (CAS) showed less E to Z isomerization when exposed to UV-B light. The absorption profiles of the product showed the maximum absorption wavelength to be similar to that of OMC but with less sensitivity to the type of solvent. Poly (methylhydrosiloxane) grafted with 10 mol% p-methoxycinnamoyl moieties was prepared through hydrosilylations of 2-propenyl-p-methoxycinnamate, in which the resulting copolymer showed similar results to those of CAS.

  16. Mycosporine-like amino acids in planktonic organisms living under different UV exposure conditions in Patagonian lakes

    Science.gov (United States)

    TARTAROTTI, BARBARA; BAFFICO, GUSTAVO; TEMPORETTI, PEDRO; ZAGARESE, HORACIO E.

    2011-01-01

    Mycosporine-like amino acids (MAAs) were studied in zooplankton from 13 Argentinian lakes covering a broad range in altitude, maximum depth and physico-chemical properties of the water. Four to nine different MAAs (predominantly porphyra-334 and shinorine) were found in the copepods Boeckella gibbosa, B. gracilipes, B. meteoris and Parabroteas sarsi, and in the ciliate Stentor amethystinus, while MAAs were undetectable in the cladoceran Daphnia middendorffiana. Among the different copepods, maximum MAA concentrations accounted for 0.25–1.31% of the dry weight, and contents were generally about three to seven times (up to 43 times) higher in the animals living in the clearest lakes compared to those occurring in low-UV systems. This variability in the content of MAAs was related to the lake altitude (r2 = 0.71), and the fraction of the water column to which 1% of the surface UV radiation at 320 nm penetrated (r2 = 0.57). Our data therefore underscore the role of MAAs as sunscreens to decrease the potential negative effects of solar radiation, but they also indicate that other environmental factors besides UV transparency play a role in determining MAA concentrations. One lake was selected to obtain additional information on the qualitative composition of MAAs in seston of <100 μm between two sampling sites and over a 2 month study period (austral summer). Six different MAAs were detected in the samples, with porphyra-334 and palythine being predominant. In the copepods collected simultaneously, there was low variation in MAA concentrations between the two sites and over time. Thus, our results suggest that under similar UV exposure conditions MAA contents of planktonic organisms show low temporal variation. PMID:21258622

  17. UV/EB curable psa's

    International Nuclear Information System (INIS)

    Glotfelter, C.A.

    1995-01-01

    The author describe both water-based and 100% solids UV/EB curable PSA's (Pressure Sensitive Adhesives) and their properties. A new acrylate monomer, ethoxylated nonyl phenol acrylate, has great utility in the formulation of water-based PSA's

  18. System for memorizing maximum values

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1992-08-01

    The invention discloses a system capable of memorizing maximum sensed values. The system includes conditioning circuitry which receives the analog output signal from a sensor transducer. The conditioning circuitry rectifies and filters the analog signal and provides an input signal to a digital driver, which may be either linear or logarithmic. The driver converts the analog signal to discrete digital values, which in turn triggers an output signal on one of a plurality of driver output lines n. The particular output lines selected is dependent on the converted digital value. A microfuse memory device connects across the driver output lines, with n segments. Each segment is associated with one driver output line, and includes a microfuse that is blown when a signal appears on the associated driver output line.

  19. Remarks on the maximum luminosity

    Science.gov (United States)

    Cardoso, Vitor; Ikeda, Taishi; Moore, Christopher J.; Yoo, Chul-Moon

    2018-04-01

    The quest for fundamental limitations on physical processes is old and venerable. Here, we investigate the maximum possible power, or luminosity, that any event can produce. We show, via full nonlinear simulations of Einstein's equations, that there exist initial conditions which give rise to arbitrarily large luminosities. However, the requirement that there is no past horizon in the spacetime seems to limit the luminosity to below the Planck value, LP=c5/G . Numerical relativity simulations of critical collapse yield the largest luminosities observed to date, ≈ 0.2 LP . We also present an analytic solution to the Einstein equations which seems to give an unboundedly large luminosity; this will guide future numerical efforts to investigate super-Planckian luminosities.

  20. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-09-07

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  1. Scintillation counter, maximum gamma aspect

    International Nuclear Information System (INIS)

    Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  2. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yi; Zhao, Shiguang; Gao, Xin

    2014-01-01

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  3. Seasonal responses of six Poaceae to differential levels of solar UV-B radiation

    International Nuclear Information System (INIS)

    Deckmyn, G.; Impens, I.

    1999-01-01

    The effects of changes in solar UV-B on the growth and pigmentation of six grass species from cold-temperate grasslands (Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca rubra, Phleum pratense and Dactylis glomerata) in spring and summer were studied. The grasses were grown in greenhouses with different foils, resulting in three treatments: no UV-B, 80% of ambient and 90% of ambient UV-BBE (biologically effective UV-B). The results indicated important effects of ambient UV-B levels on grass, but the different species reacted in very different ways. Both morphology and biomass production were influenced by UV-B in some species. However, changes in biomass production did not necessarily occur within the same species as changes in morphology. The grasses were more sensitive in summer. Overall, only F. rubra was positively influenced by UV-B under all circumstances. The biomass of D. glomerata and L. perenne was reduced by UV-B in spring and summer. Morphological changes included reduced height and increased tillering. The sensitivity of the different species was partially explained by their ability to reduce their specific leaf area in response to UV-B. Only the more sensitive species showed increased production of protective pigments. Overall, there were important differences between the effect of a low level of UV-B, and the further increase in UV-B, indicating that several mechanisms are operating at different light levels. (author)

  4. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    Energy Technology Data Exchange (ETDEWEB)

    Albert, K.R.; Ro-Poulsen, H. (Univ. of Copenhagen, Dept. of Terrestrial Ecology, Copenhagen (DK)); Mikkelsen, T.N. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Biosystems Dept., Roskilde (DK))

    2008-06-15

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B. (au)

  5. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum.

    Science.gov (United States)

    Albert, Kristian R; Mikkelsen, Teis N; Ro-Poulsen, Helge

    2008-06-01

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B.

  6. High current photoemission with 10 picosecond uv pulses

    International Nuclear Information System (INIS)

    Fischer, J.; Srinivasan-Rao, T.; Tsang, T.

    1990-06-01

    The quantum efficiency and the optical damage threshold of various metals were explored with 10 ps, 266 nm, UV laser pulses. Efficiencies for Cu, Y, and Sm were: 1.4, 5, and 7 x 10 -4 , with damage thresholds about 100, 10, and 30 mJ/cm 2 . This would permit over 1 μC/cm 2 or current densities exceeding 100 kA/cm 2 . High charge and current densities of up to 66 kA/cm 2 were obtained on 0.25 mm diam cathodes, and 21 kA/cm 2 on a 3 mm diam yttrium cathode. The maximum currents were limited by space charge and the dc field. The experiments with small area illumination indicate that the emitted electrons spread transversely due to Coulomb repulsion and their initial transverse velocity. This increases the effective area above the cathode, reduces the space charge effect and increases emission density on the cathode. The quantum efficiency can be increased substantially by enhancing the field on the surface by either a suitable electrode geometry or microstructures on it. 14 refs., 12 figs., 3 tabs

  7. A critical assessment of two types of personal UV dosimeters.

    Science.gov (United States)

    Seckmeyer, Gunther; Klingebiel, Marcus; Riechelmann, Stefan; Lohse, Insa; McKenzie, Richard L; Liley, J Ben; Allen, Martin W; Siani, Anna-Maria; Casale, Giuseppe R

    2012-01-01

    Doses of erythemally weighted irradiances derived from polysulphone (PS) and electronic ultraviolet (EUV) dosimeters have been compared with measurements obtained using a reference spectroradiometer. PS dosimeters showed mean absolute deviations of 26% with a maximum deviation of 44%, the calibrated EUV dosimeters showed mean absolute deviations of 15% (maximum 33%) around noon during several test days in the northern hemisphere autumn. In the case of EUV dosimeters, measurements with various cut-off filters showed that part of the deviation from the CIE erythema action spectrum was due to a small, but significant sensitivity to visible radiation that varies between devices and which may be avoided by careful preselection. Usually the method of calibrating UV sensors by direct comparison to a reference instrument leads to reliable results. However, in some circumstances the quality of measurements made with simple sensors may be over-estimated. In the extreme case, a simple pyranometer can be used as a UV instrument, providing acceptable results for cloudless skies, but very poor results under cloudy conditions. It is concluded that while UV dosimeters are useful for their design purpose, namely to estimate personal UV exposures, they should not be regarded as an inexpensive replacement for meteorological grade instruments. © 2011 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

  8. UV-induced N2O emission from plants

    Science.gov (United States)

    Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

    2014-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  9. Degradation of sulfamethoxazole by UV, UV/H2O2 and UV/persulfate (PDS): Formation of oxidation products and effect of bicarbonate.

    Science.gov (United States)

    Yang, Yi; Lu, Xinglin; Jiang, Jin; Ma, Jun; Liu, Guanqi; Cao, Ying; Liu, Weili; Li, Juan; Pang, Suyan; Kong, Xiujuan; Luo, Congwei

    2017-07-01

    The frequent detection of sulfamethoxazole (SMX) in wastewater and surface waters gives rise of concerns about their ecotoxicological effects and potential risks to induce antibacterial resistant genes. UV/hydrogen peroxide (UV/H 2 O 2 ) and UV/persulfate (UV/PDS) advanced oxidation processes have been demonstrated to be effective for the elimination of SMX, but there is still a need for a deeper understanding of product formations. In this study, we identified and compared the transformation products of SMX in UV, UV/H 2 O 2 and UV/PDS processes. Because of the electrophilic nature of SO 4 - , the second-order rate constant for the reaction of sulfate radical (SO 4 - ) with the anionic form of SMX was higher than that with the neutral form, while hydroxyl radical (OH) exhibited comparable reactivity to both forms. The direct photolysis of SMX predominately occurred through cleavage of the NS bond, rearrangement of the isoxazole ring, and hydroxylation mechanisms. Hydroxylation was the dominant pathway for the reaction of OH with SMX. SO 4 - favored attack on NH 2 group of SMX to generate a nitro derivative and dimeric products. The presence of bicarbonate in UV/H 2 O 2 inhibited the formation of hydroxylated products, but promoted the formation of the nitro derivative and the dimeric products. In UV/PDS, bicarbonate increased the formation of the nitro derivative and the dimeric products, but decreased the formation of the hydroxylated dimeric products. The different effect of bicarbonate on transformation products in UV/H 2 O 2 vs. UV/PDS suggested that carbonate radical (CO 3 - ) oxidized SMX through the electron transfer mechanism similar to SO 4 - but with less oxidation capacity. Additionally, SO 4 - and CO 3 - exhibited higher reactivity to the oxazole ring than the isoxazole ring of SMX. Ecotoxicity of transformation products was estimated by ECOSAR program based on the quantitative structure-activity relationship analysis as well as by experiments using

  10. Bovine ocular squamous cell carcinoma: UV sensitivity in lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lavin, M.F.; Jennings, P.A.; Hughes, D.J. (Queensland Univ., Brisbane (Australia))

    1982-05-01

    Increased sensitivity to UV light has been demonstrated in Phytohaemagglutinin stimulated lymphocytes from normal and tumour-bearing Hereford cattle when compared to lymphocytes from other breeds. Trypan blue exclusion and inhibition of DNA synthesis were used to determine cell viability. The results obtained from time course and radiation dose experiments demonstrate biphasic survival kinetics. This is indicative of at least two separate cell populations, exhibiting differential sensitivity to UV. The increased sensitivity to UV observed in Herefords may reflect a general sensitivity to UV or alternatively a different cellular constitution in the mitogen stimulated cultures. DNA repair synthesis, measured in the presence of hydroxyurea, was of similar levels in cell cultures from Herefords and one of the control breeds.

  11. Bovine ocular squamous cell carcinoma: UV sensitivity in lymphocytes

    International Nuclear Information System (INIS)

    Lavin, M.F.; Jennings, P.A.; Hughes, D.J.

    1982-01-01

    Increased sensitivity to UV light has been demonstrated in Phytohaemagglutinin stimulated lymphocytes from normal and tumour-bearing Hereford cattle when compared to lymphocytes from other breeds. Trypan blue exclusion and inhibition of DNA synthesis were used to determine cell viability. The results obtained from time course and radiation dose experiments demonstrate biphasic survival kinetics. This is indicative of at least two separate cell populations, exhibiting differential sensitivity to UV. The increased sensitivity to UV observed in Herefords may reflect a general sensitivity to UV or alternatively a different cellular constitution in the mitogen stimulated cultures. DNA repair synthesis, measured in the presence of hydroxyurea, was of similar levels in cell cultures from Herefords and one of the control breeds. (author)

  12. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND, B.M.

    2001-07-26

    Organisms living on the earth are exposed to solar radiation, including its ultraviolet (UV) components (for general reviews, the reader is referred to Smith [1] and Young et al. [2]). UV wavelength regions present in sunlight are frequently designated as UVB (290-320 nm) and UVA (320-400 nm). In today's solar spectrum, UVA is the principal UV component, with UVB present at much lower levels. Ozone depletion will increase the levels of UVB reaching the biosphere, but the levels of UVA will not be changed significantly [3]. Because of the high efficiency of UVB in producing damage in biological organisms in the laboratory experiments, it has sometimes been assumed that UVA has little or no adverse biological effects. However, accumulating data [4, 5], including action spectra (efficiency of biological damage as a function of wavelength of radiation; see Section 5) for DNA damage in alfalfa seedlings [6], in human skin [7], and for a variety of plant damages (Caldwell, this volume) indicate that UVA can induce damage in DNA in higher organisms. Thus, understanding the differential effects of UVA and UVB wavebands is essential for estimating the biological consequences of stratospheric ozone depletion.

  13. RNA synthesis during germination of UV-irradiated Dictyostelium discoideum spores

    International Nuclear Information System (INIS)

    Okaichi, Kumio

    1987-01-01

    UV irradiation to the spores of Dictyostelium discoideum NC4 resulted in a more prolonged delay of amoeba-emergence from swollen spores with increasing UV fluence. During the germination, an inhibition of total RNA synthesis and a shift of stage of maximum RNA synthesis to the later period were observed. The maximum poly(A) + RNA synthetic activity was found on an early stage of amoeba-emergence prior about 1 h to the beginning of rRNA synthesis in unirradiated spore germination; but, in UV-irradiated spore germination, the stage of maximum poly(A) + RNA synthesis shifted to the later stage of germination with increasing UV fluence. A decreased synthesis of poly(A) + RNA and a severe inhibition of rRNA synthesis were observed on UV-irradiated and germinated spores, but no significant inhibition of 4 - 5 S RNA synthesis was detected. Actinomycin D suppressed almost completely the rRNA synthesis of emerged amoebae but the drug apparently did not affect the emergence of amoebae at any stage of germination. It was postulated that the delay of amoeba-emergence in UV-irradiated spore must be mainly due to the shift of the stage of maximum synthesis of poly(A) + RNA to the later stage of germination. (author)

  14. UV-screening chitosan nanocontainers: increasing the photostability of encapsulated materials and controlled release

    International Nuclear Information System (INIS)

    Anumansirikul, Nattaporm; Wittayasuporn, Mayura; Klinubol, Patcharawalai; Tachaprutinun, A; Wanichwecharungruang, Supason P

    2008-01-01

    Methyl ether terminated poly(ethylene glycol)-4-methoxycinnamoylphthaloylchitosan (PCPLC), a UV absorptive polymer, and methyl ether terminated poly(ethylene glycol)-phthaloylchitosan (PPLC) were synthesized, characterized and self-assembled into stable water-dispersible spherical nanoparticles. The encapsulation of a model compound, 2-ethylhexyl-4-methoxycinnamate (EHMC), was carried out to give particles with 67% (w/w) EHMC loading. The E to Z photoisomerization of EHMC encapsulated inside both particles was monitored and compared to non-encapsulated EHMC. Minimal E to Z photoisomerization was observed when EHMC was encapsulated in PCPLC particles prepared from a polymer with a maximum degree of 4-methoxycinnamoyl substitution. The results indicated that the grafted UVB absorptive chromophore, 4-methoxycinnamoyl moieties, situated at the shell of PCPLC nanoparticles acted as a UV-filtering barrier, protecting the encapsulated EHMC from the UVB radiation, thus minimizing its photoisomerization. In vitro experiments revealed the pH-dependent controlled release of EHMC from PCPLC and PPLC particles. Ex vivo experiments, using a Franz diffusion cell with baby mouse skin, indicated that neither PPLC nor PCPLC particles could penetrate the skin into the receptor medium after a 24 h topical application. When applied on the baby mouse skin, both EHMC-encapsulated PPLC and EHMC-encapsulated PCPLC showed comparable controlled releases of the EHMC. The released EHMC could transdermally penetrate the baby mouse skin

  15. UV-screening chitosan nanocontainers: increasing the photostability of encapsulated materials and controlled release

    Science.gov (United States)

    Anumansirikul, Nattaporm; Wittayasuporn, Mayura; Klinubol, Patcharawalai; Tachaprutinun, A.; Wanichwecharungruang, Supason P.

    2008-05-01

    Methyl ether terminated poly(ethylene glycol)-4-methoxycinnamoylphthaloylchitosan (PCPLC), a UV absorptive polymer, and methyl ether terminated poly(ethylene glycol)-phthaloylchitosan (PPLC) were synthesized, characterized and self-assembled into stable water-dispersible spherical nanoparticles. The encapsulation of a model compound, 2-ethylhexyl-4-methoxycinnamate (EHMC), was carried out to give particles with 67% (w/w) EHMC loading. The E to Z photoisomerization of EHMC encapsulated inside both particles was monitored and compared to non-encapsulated EHMC. Minimal E to Z photoisomerization was observed when EHMC was encapsulated in PCPLC particles prepared from a polymer with a maximum degree of 4-methoxycinnamoyl substitution. The results indicated that the grafted UVB absorptive chromophore, 4-methoxycinnamoyl moieties, situated at the shell of PCPLC nanoparticles acted as a UV-filtering barrier, protecting the encapsulated EHMC from the UVB radiation, thus minimizing its photoisomerization. In vitro experiments revealed the pH-dependent controlled release of EHMC from PCPLC and PPLC particles. Ex vivo experiments, using a Franz diffusion cell with baby mouse skin, indicated that neither PPLC nor PCPLC particles could penetrate the skin into the receptor medium after a 24 h topical application. When applied on the baby mouse skin, both EHMC-encapsulated PPLC and EHMC-encapsulated PCPLC showed comparable controlled releases of the EHMC. The released EHMC could transdermally penetrate the baby mouse skin.

  16. DNA damage caused by UV- and near UV-irradiation

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1986-01-01

    Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

  17. Investigations of uv TEA N/sub 2/ lasers

    Energy Technology Data Exchange (ETDEWEB)

    Santa, I; Racz, B; Kozma, L; Nemet, B

    1978-01-01

    A simple transversely excited atmospheric (TEA) nitrogen uv laser with double Blumlein-circuit switched by triggered spark gap was investigated. The Blumlein-circuits were based on flatplate wave guide and ceramic capacitors, as well. The output laser energy and the pulse shape exhibited strong dependence on the setting of the angle between the two laser electrodes, but less on the electrode separation. The minimum flowing rate to obtain the maximum output energy was determined at 25 and 50 Hz repetition rate.

  18. Empirical Productivity Indices and Indicators

    NARCIS (Netherlands)

    B.M. Balk (Bert)

    2016-01-01

    textabstractThe empirical measurement of productivity change (or difference) by means of indices and indicators starts with the ex post profit/loss accounts of a production unit. Key concepts are profit, leading to indicators, and profitability, leading to indices. The main task for the productivity

  19. Two-components UV-therapy

    International Nuclear Information System (INIS)

    Pullmann, H.; Steigleder, G.K.

    1980-01-01

    20 patients with generalized psoriasis were treated with an apparatus containing UV-A- and UV-B-fluorescence tubes to be switched separately. The therapy was started with an UV-A-dose of 12 J/cm 2 daily. After the first week of treatment UV-B in increasing doses was applicated additionally. Clearance was achieved in 80 percent. (orig.) [de

  20. Maximum entropy and Bayesian methods

    International Nuclear Information System (INIS)

    Smith, C.R.; Erickson, G.J.; Neudorfer, P.O.

    1992-01-01

    Bayesian probability theory and Maximum Entropy methods are at the core of a new view of scientific inference. These 'new' ideas, along with the revolution in computational methods afforded by modern computers allow astronomers, electrical engineers, image processors of any type, NMR chemists and physicists, and anyone at all who has to deal with incomplete and noisy data, to take advantage of methods that, in the past, have been applied only in some areas of theoretical physics. The title workshops have been the focus of a group of researchers from many different fields, and this diversity is evident in this book. There are tutorial and theoretical papers, and applications in a very wide variety of fields. Almost any instance of dealing with incomplete and noisy data can be usefully treated by these methods, and many areas of theoretical research are being enhanced by the thoughtful application of Bayes' theorem. Contributions contained in this volume present a state-of-the-art overview that will be influential and useful for many years to come

  1. Gas phase UV and IR absorption spectra of CxF2x+1CHO (x=1-4)

    DEFF Research Database (Denmark)

    Hashikawa, Y; Kawasaki, M; Waterland, RL

    2004-01-01

    The UV and IR spectra of CxF2x+1 CHO (x = 1-4) were investigated using computational and experimental techniques. CxF2x+1CHO (x = 1-4) have broad UV absorption features centered at 300-310 nm. The maximum absorption cross-section increases significantly and shifts slightly to the red with increased...

  2. Flare-related color effects in UV Ceti stars

    International Nuclear Information System (INIS)

    Flesch, T.R.

    1975-01-01

    The UV Ceti flare stars YZ CMi, BD+16 0 2708, EV Lac, and AD Leo were monitored photoelectrically for flare activity with the 76 centimeter reflecting telescope of the University of Florida's Rosemary Hill Observatory. Observations were carried out from January, 1973 to April, 1975. The instrumentation allowed simultaneous readings to be taken at 3500, 4632, and 6496A with a time resolution of 2 seconds. A total of 15 major events were observed, with 14 of these being observed in all three colors. All events showed the classical fast rise and slower decline that is typical of this type of activity. One event showed peculiar behavior in the red bandpass that may indicate strong dependence of the flare light in some cases on line emission. The data were applied to the fast electron model of flare activity proposed by Gurzadyan. Several serious inconsistencies in the theory were found that would not have been evident in single-channel monitoring. No event could be fitted in all three colors using consistent values of the unknown parameters in the theory. The most serious deficiencies in the theory were the wavelength dependence of the optical depth of the electron cloud and the lack of treatment of line emission behavior. Differential color indices for flare light are calculated and are shown to be essentially constant throughout the entire event for the stronger flares. A color-color plot of the flare light at maximum reveals that 11 of the flares show a linear relation. This relation indicates that the smaller the u-b index, the larger is the b-r index. This is probably directly involved with line emission during flare events. Future research possibilities are discussed, with spectroscopic studies and simultaneous multicolor observations being stressed

  3. Tunable UV Filters

    Science.gov (United States)

    Bruner, Marilyn E. (Principal Investigator); Rosenberg, William A.

    1996-01-01

    This report describes an investigation intended to determine the practical short wavelength limit for Fabry-Perot etalons operating in the far ultraviolet. This portion of the investigation includes a design study of multilayer dielectric reflector coatings that would be required by such an etalon. Results of the study indicate that etalons may be made to operate at wavelengths as short as 121 nm.

  4. Maximum entropy principal for transportation

    International Nuclear Information System (INIS)

    Bilich, F.; Da Silva, R.

    2008-01-01

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

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

    Science.gov (United States)

    Allen, Martin; McKenzie, Richard

    2005-05-01

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

  6. Microbial Removal Efficiency of UV in Tehran Shahid Mahallati Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Reza Dabbagh

    2009-03-01

    Full Text Available Shahid Mahallati Wastewater Treatment Plant was selected for installing a UV disinfection unit to investigate its germicidal effect on microbial removal. Low pressure mercury lamps were used to generate germicidal ultraviolet radiation (UV-C. The UV system was operated over a period of 6 months that included both warm and cold seasons. A maximum UV disinfection efficiency of 14.4m3/h was recorded for the system on the basis of design criteria within turbidity ranges of 9 to 32 NTU. The minimum UV dose applied in the UV unit was 40000 µW.s/cm2 and the highest bacterial density in the UV unit influent was 5.6*107. Effluent total coliform or fecal coliform enumeration after exposure to UV ray showed the microbial density decreasing from four logs, or 99.99%, to as high as six logs, or 99.9999% removal efficiency, under different conditions. Effluent microbial densities in terms of total and fecal coliforms were below 1000MPN/100mL and 400MPN/100mL, respectively. These values comply with wastewater discharge or agricultural irrigation standards according to Iran Department of Environment. From our results, it is concluded that UV disinfection may be an effective technique for wastewater disinfection in Iranian wastewater treatment plants.

  7. Waste indicators

    Energy Technology Data Exchange (ETDEWEB)

    Dall, O.; Lassen, C.; Hansen, E. [Cowi A/S, Lyngby (Denmark)

    2003-07-01

    The Waste Indicator Project focuses on methods to evaluate the efficiency of waste management. The project proposes the use of three indicators for resource consumption, primary energy and landfill requirements, based on the life-cycle principles applied in the EDIP Project. Trial runs are made With the indicators on paper, glass packaging and aluminium, and two models are identified for mapping the Danish waste management, of which the least extensive focuses on real and potential savings. (au)

  8. Waste indicators

    International Nuclear Information System (INIS)

    Dall, O.; Lassen, C.; Hansen, E.

    2003-01-01

    The Waste Indicator Project focuses on methods to evaluate the efficiency of waste management. The project proposes the use of three indicators for resource consumption, primary energy and landfill requirements, based on the life-cycle principles applied in the EDIP Project. Trial runs are made With the indicators on paper, glass packaging and aluminium, and two models are identified for mapping the Danish waste management, of which the least extensive focuses on real and potential savings. (au)

  9. Quality indicators

    DEFF Research Database (Denmark)

    Hjorth-Andersen, Christian

    1991-01-01

    In recent literature it has been suggested that consumers need have no knowledge of product quality as a number of quality indicators (or signals) may be used as substitutes. Very little attention has been paid to the empirical verification of these studies. The present paper is devoted...... to the issue of how well these indicators perform, using market data provided by consumer magazines from 3 countries. The results strongly indicate that price is a poor quality indicator. The paper also presents some evidence which suggests that seller reputation and easily observable characteristics are also...

  10. The role of natural organic matter in nitrite formation by LP-UV/H2O2 treatment of nitrate-rich water.

    Science.gov (United States)

    Semitsoglou-Tsiapou, Sofia; Mous, Astrid; Templeton, Michael R; Graham, Nigel J D; Hernández Leal, Lucía; Kruithof, Joop C

    2016-12-01

    The role of natural organic matter (NOM) on nitrite formation from nitrate photolysis by low pressure ultraviolet lamp (LP-UV) photolysis and LP-UV/H 2 O 2 treatment was investigated. Nitrate levels up to the WHO guideline maximum of 50 mg NO 3 - /L were used in tests. The presence of 4 mg/L Suwannee River natural organic matter (NOM) led to increased nitrite yields compared to NOM-free controls. This was caused partly by NOM scavenging of OH radicals, preserving the produced NO 2 - as well as the ONOO - that leads to NO 2 - formation, but also via the production of radical species ( 1 O 2 , O 2 - and OH) by the photolysis of NOM. In addition, solvated electrons formed by NOM photolysis may reduce nitrate directly to nitrite. For comparison, Nordic Lake NOM, representative of aquatic NOM, as well as Pony Lake NOM, which had a greater nitrogen content (6.51% w/w) than the other two types of NOM, were investigated, yielding similar nitrite levels as Suwannee River NOM. The results suggest that neither the type nor the nitrogen content of the NOM have an effect on the nitrite yields obtained over the range of UV/H 2 O 2 doses applied (UV fluences of 500-2100 mJ/cm 2 and hydrogen peroxide doses of 10, 25, and 50 mg/L). The findings indicate that for UV fluences above 1500 mJ/cm 2 the resulting nitrite concentration can exceed the 0.1 mg/L EU regulatory limit for nitrite, suggesting that nitrite formation by LP-UV advanced oxidation of nitrate-rich waters is important to consider. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Last Glacial Maximum Salinity Reconstruction

    Science.gov (United States)

    Homola, K.; Spivack, A. J.

    2016-12-01

    It has been previously demonstrated that salinity can be reconstructed from sediment porewater. The goal of our study is to reconstruct high precision salinity during the Last Glacial Maximum (LGM). Salinity is usually determined at high precision via conductivity, which requires a larger volume of water than can be extracted from a sediment core, or via chloride titration, which yields lower than ideal precision. It has been demonstrated for water column samples that high precision density measurements can be used to determine salinity at the precision of a conductivity measurement using the equation of state of seawater. However, water column seawater has a relatively constant composition, in contrast to porewater, where variations from standard seawater composition occur. These deviations, which affect the equation of state, must be corrected for through precise measurements of each ion's concentration and knowledge of apparent partial molar density in seawater. We have developed a density-based method for determining porewater salinity that requires only 5 mL of sample, achieving density precisions of 10-6 g/mL. We have applied this method to porewater samples extracted from long cores collected along a N-S transect across the western North Atlantic (R/V Knorr cruise KN223). Density was determined to a precision of 2.3x10-6 g/mL, which translates to salinity uncertainty of 0.002 gms/kg if the effect of differences in composition is well constrained. Concentrations of anions (Cl-, and SO4-2) and cations (Na+, Mg+, Ca+2, and K+) were measured. To correct salinities at the precision required to unravel LGM Meridional Overturning Circulation, our ion precisions must be better than 0.1% for SO4-/Cl- and Mg+/Na+, and 0.4% for Ca+/Na+, and K+/Na+. Alkalinity, pH and Dissolved Inorganic Carbon of the porewater were determined to precisions better than 4% when ratioed to Cl-, and used to calculate HCO3-, and CO3-2. Apparent partial molar densities in seawater were

  12. Maximum Parsimony on Phylogenetic networks

    Science.gov (United States)

    2012-01-01

    Background Phylogenetic networks are generalizations of phylogenetic trees, that are used to model evolutionary events in various contexts. Several different methods and criteria have been introduced for reconstructing phylogenetic trees. Maximum Parsimony is a character-based approach that infers a phylogenetic tree by minimizing the total number of evolutionary steps required to explain a given set of data assigned on the leaves. Exact solutions for optimizing parsimony scores on phylogenetic trees have been introduced in the past. Results In this paper, we define the parsimony score on networks as the sum of the substitution costs along all the edges of the network; and show that certain well-known algorithms that calculate the optimum parsimony score on trees, such as Sankoff and Fitch algorithms extend naturally for networks, barring conflicting assignments at the reticulate vertices. We provide heuristics for finding the optimum parsimony scores on networks. Our algorithms can be applied for any cost matrix that may contain unequal substitution costs of transforming between different characters along different edges of the network. We analyzed this for experimental data on 10 leaves or fewer with at most 2 reticulations and found that for almost all networks, the bounds returned by the heuristics matched with the exhaustively determined optimum parsimony scores. Conclusion The parsimony score we define here does not directly reflect the cost of the best tree in the network that displays the evolution of the character. However, when searching for the most parsimonious network that describes a collection of characters, it becomes necessary to add additional cost considerations to prefer simpler structures, such as trees over networks. The parsimony score on a network that we describe here takes into account the substitution costs along the additional edges incident on each reticulate vertex, in addition to the substitution costs along the other edges which are

  13. Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile Respuestas fotosintéticas a la radiación UV en algas intermareales del Estrecho de Magallanes (Chile

    Directory of Open Access Journals (Sweden)

    RALF RAUTENBERGER

    2009-03-01

    Full Text Available For the first time, the photosynthetic performance of field-grown macroalgae from the Magellan Strait was evaluated with respect to their photoadaptation in the field and acclimation potential to ultraviolet radiation. Five macroalgal species were collected in the eulittoral and the upper sublittoral: Ulva intestinalis, Porphyra columbina, Adenocystis utricularis, Desmarestia confervoides and D. ligulata. Photosynthesis vs. irradiance (P-I curves of macroalgae cultivated in the laboratory under low white light intensities more than a week were used to assess the acclimation potential to irradiance conditions in the field. Both, photosynthetic parameters referred to as maximum electron transport rate (ETRmax and light saturation points of photosynthesis (Ik were species-specific and did not correlate with the position on the shore. Ik ranging between 80 and 215 μmol photons m-2 s-1 was indicative of moderate sun-adaptation in all studied species. The acclimation potential to UV-radiation was determined as the extent and the rates (m inh of PSII inhibition (resulting from decreased maximum PSII-quantum yield (Fv/Fm after four hours of UV-exposure and as the subsequent rates of recovery (m in dim PAR. The results suggest that photosynthesis of each species during UV-exposure was transiently down regulated rather than damaged. Furthermore, no reductions in ETRmax were detected after 4 h exposure to UV-A and UV-B-radiation, and consequently the Calvin cycle could not be affected. Thus, Fv/Fm was a more sensitive parameter than ETRmax explaining the photosynthetic UV acclimation. Both, the rates of inhibition and the rates of recovery were not correlated with the morpho-functional groups of macroalgae nor to their vertical distribution. Thus, although the capacity to acclimate to UV-radiation varied among the different species, data suggest that such responses are based on metabolic adjustments or possibly photoprotective strategies. In conclusion

  14. Characterization of antibodies specific for UV-damaged DNA by ELISA

    Energy Technology Data Exchange (ETDEWEB)

    Eggset, G; Volden, G; Krokan, H

    1987-04-01

    The specificity of affinity purified antibodies raised against UV-irradiated DNA was examined using an enzyme-linked immunosorbent assay. DNA irradiated with UV doses higher than needed for saturation with pyrimidine dimers bound increasing amounts of antibody. Photosensitized DNA, containing high amounts of pyrimidine dimers, showed very poor binding of antibody. When UV-irradiated DNA was given a second dose of 340-nm UV light, the binding of antibodies was inhibited. Taken together, this indicates a major specificity for (6-4)-photoproducts, which are photochemically reversed by UV light in the 340-nm region. The antibodies also showed little but detectable binding to pyrimidine glycols produced in DNA by oxidation with OsO/sub 4/. Previously, we have used these antibodies for the detection of UV-induced DNA damage and its repair in human skin in vivo. These findings indicate that (6-4)-photoproducts, considered highly mutagenic, are repaired in human skin.

  15. Characterization of antibodies specific for UV-damaged DNA by ELISA

    International Nuclear Information System (INIS)

    Eggset, G.; Volden, G.; Krokan, H.; Norsk Hydro Research Centre, Porsgrunn

    1987-01-01

    The specificity of affinity purified antibodies raised against UV-irradiated DNA was examined using an enzyme-linked immunosorbent assay. DNA irradiated with UV doses higher than needed for saturation with pyrimidine dimers bound increasing amounts of antibody. Photosensitized DNA, containing high amounts of pyrimidine dimers, showed very poor binding of antibody. When UV-irradiated DNA was given a second dose of 340-nm UV light, the binding of antibodies was inhibited. Taken together, this indicates a major specificity for (6-4)-photoproducts, which are photochemically reversed by UV light in the 340-nm region. The antibodies also showed little but detectable binding to pyrimidine glycols produced in DNA by oxidation with OsO 4 . Previously, we have used these antibodies for the detection of UV-induced DNA damage and its repair in human skin in vivo. These findings indicate that (6-4)-photoproducts, considered highly mutagenic, are repaired in human skin. (author)

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

    Science.gov (United States)

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

    2008-02-01

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

  17. General indicators

    International Nuclear Information System (INIS)

    2003-01-01

    This document summarizes the main 2002 energy indicators for France. A first table lists the evolution of general indicators between 1973 and 2002: energy bill, price of imported crude oil, energy independence, primary and final energy consumption. The main 2002 results are detailed separately for natural gas, petroleum and coal (consumption, imports, exports, production, stocks, prices). (J.S.)

  18. Scattered UV irradiation during VISX excimer laser keratorefractive surgery.

    Science.gov (United States)

    Hope, R J; Weber, E D; Bower, K S; Pasternak, J P; Sliney, D H

    2008-04-01

    To evaluate the potential occupational health hazards associated with scattered ultraviolet (UV) radiation during photorefractive keratectomy (PRK) using the VISX Star S3 excimer laser. The Laser Vision Center, National Naval Medical Center, Bethesda, Maryland, USA. Intraoperative radiometric measurements were made with the Ophir Power/Energy Meter (LaserStar Model PD-10 with silicon detector) during PRK treatments as well as during required calibration procedures at a distance of 20.3 cm from the left cornea. These measurements were evaluated using a worst-case scenario for exposure, and then compared with the American Conference of Governmental Industrial Hygeinists (ACGIH) Threshold Value Limits (TVL) to perform a risk/hazard analysis. During the PRK procedures, the highest measured value was 248.4 nJ/pulse. During the calibration procedures, the highest measured UV scattered radiation level was 149.6 nJ/pulse. The maximum treatment time was 52 seconds. Using a worst-case scenario in which all treatments used the maximum power and time, the total energy per eye treated was 0.132 mJ/cm2 and the total UV radiation at close range (80 cm from the treated eye) was 0.0085 mJ/cm2. With a workload of 20 patients, the total occupational exposure at 80 cm to actinic UV radiation in an 8-hour period would be 0.425 mJ/cm2. The scattered actinic UV laser radiation from the VISX Star S3 excimer laser did not exceed occupational exposure limits during a busy 8-hour workday, provided that operating room personnel were at least 80 cm from the treated eye. While the use of protective eyewear is always prudent, this study demonstrates that the trace amounts of scattered laser emissions produced by this laser do not pose a serious health risk even without the use of protective eyewear.

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

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  20. Monoclonal antibodies reactive with common tumor antigens on UV-induced tumors also react with hyperplastic UV-irradiated skin

    International Nuclear Information System (INIS)

    Spellman, C.W.; Beauchamp, D.A.

    1986-01-01

    Most murine skin tumors induced by ultraviolet light (UVB, 280-340 nm) can be successfully transplanted only into syngeneic hosts that have received subcarcinogenic doses of UVB. The tumor susceptible state is long-lived and mediated by T suppressor cells that control effector responses against common antigens on UV-induced tumors. Because antigen specific suppression arises prior to the appearance of a tumor, questions arise about the source of the original antigen. They have previously reported transplantation studies indicating that UV-irradiated skin is antigenically cross-reactive with UV-induced tumors. They now report on flow cytometry analyses showing that a series of MoAb reactive with common antigens expressed by UV-induced tumors are also reactive on cells from UV-irradiated skin. Various antigens appear at different times in the UV irradiation scheme, and some persist while others are transient. They speculate that the common antigens detected may be the ones to which functional suppression is directed. If true, these results suggest that successful tumors need not escape host defenses to emerge. Rather, tumors may arise and grow progressively if they express antigens that cross-react with specificities to which the host has previously mounted a suppressive response

  1. uvbyHβ photometry of UV-bright stars

    International Nuclear Information System (INIS)

    Wade, B.R.; Smith, L.F.

    1985-01-01

    uvbyHβ photometry is presented for 90 stars taken from an early version of the Carnochan and Wilson catalogue (1983. Mon. Not. R. astr. Soc. 202,317) of stars that have very negative UV colours. Two have definite UV excesses, (HD 36629, and HD81307). Four early-B stars have UV colours too positive for their visible classification, and β-indices that indicate higher luminosities than appear possible on galactic distribution grounds. Six late-B stars appear to have discordant flux distributions for which there are no obvious explanations. It is suggested that the high population of subluminous stars derived by Carnochan and Wilson is the product of the statistical treatment used and the extreme patchiness in the interstellar absorption. (author)

  2. Past Changes in Arctic Terrestrial Ecosystems, Climate and UV Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Callaghan, Terry V. [Abisko Scientific Research Station, Abisko (Sweden); Bjoern, Lars Olof [Lund Univ. (Sweden). Dept. of Cell and Organism Biology; Chernov, Yuri [Russian Academy of Sciences, Moscow (Russian Federation). A.N. Severtsov Inst. of Evolutionary Morphology and Animal Ecology] (and others)

    2004-11-01

    At the last glacial maximum, vast ice sheets covered many continental areas. The beds of some shallow seas were exposed thereby connecting previously separated landmasses. Although some areas were ice-free and supported a flora and fauna, mean annual temperatures were 10-13 deg C colder than during the Holocene. Within a few millennia of the glacial maximum, deglaciation started, characterized by a series of climatic fluctuations between about 18,000 and 11,400 years ago. Following the general thermal maximum in the Holocene, there has been a modest overall cooling trend, superimposed upon which have been a series of millennial and centennial fluctuations in climate such as the 'Little Ice Age' spanning approximately the late 13th to early 19th centuries. Throughout the climatic fluctuations of the last 150,000 years, Arctic ecosystems and biota have been close to their minimum extent within the most recent 10,000 years. They suffered loss of diversity as a result of extinctions during the most recent large-magnitude rapid global warming at the end of the last glacial stage. Consequently, Arctic ecosystems and biota such as large vertebrates are already under pressure and are particularly vulnerable to current and projected future global warming. Evidence from the past indicates that the treeline will very probably advance, perhaps rapidly, into tundra areas, as it did during the early Holocene, reducing the extent of tundra and increasing the risk of species extinction. Species will very probably extend their ranges northwards, displacing Arctic species as in the past. However, unlike the early Holocene, when lower relative sea level allowed a belt of tundra to persist around at least some parts of the Arctic basin when treelines advanced to the present coast, sea level is very likely to rise in future, further restricting the area of tundra and other treeless Arctic ecosystems. The negative response of current Arctic ecosystems to global climatic

  3. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  4. Near UV Aerosol Group Report

    Science.gov (United States)

    Torres, Omar

    2013-01-01

    2012-13 Report of research on aerosol and cloud remote sensing using UV observations. The document was presented at the 2013 AEROCENTER Annual Meeting held at the GSFC Visitors Center, May 31, 2013. The Organizers of the meeting are posting the talks to the public Aerocentr website, after the meeting.

  5. Two-dimensional maximum entropy image restoration

    International Nuclear Information System (INIS)

    Brolley, J.E.; Lazarus, R.B.; Suydam, B.R.; Trussell, H.J.

    1977-07-01

    An optical check problem was constructed to test P LOG P maximum entropy restoration of an extremely distorted image. Useful recovery of the original image was obtained. Comparison with maximum a posteriori restoration is made. 7 figures

  6. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  9. Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1-xN Buffer Layer.

    Science.gov (United States)

    Lee, Chang-Ju; Won, Chul-Ho; Lee, Jung-Hee; Hahm, Sung-Ho; Park, Hongsik

    2017-07-21

    The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded Al x Ga -x N buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded Al x Ga 1-x N buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10 - ² A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

  10. UV and vacuum-UV biological spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Ito, Amando Siuiti

    1996-01-01

    Full text. Synchrotron radiation has been used as light source in the UV and VUV region for the study of many biological systems. In the time domain, measurements are made that allow the observation of dynamics and kinetics of biomolecules like proteins and peptides, using the fluorescent properties of either intrinsic or extrinsic probes. Optical activity of groups inside biomolecules allows the use of circular dichroism techniques to generate structural information and to follow processes like protein folding. Confocal scanning of synchrotron light generates microscopy resolution below 100 nm, allowing the creation of high quality three dimensional images of biological samples, and the collection of fluorescence originated from microvolumes inside the samples. We propose a station at LNLS for these three techniques: time-resolved fluorescence, circular dischroism and confocal microscopy, using UV and VUV light. (author)

  11. Effect of arsenite on the DNA repair of UV-irradiated Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee-Chen, S.F.; Yu, C.T.; Jan, K.Y. (Academia Sinica, Taipei, (Taiwan). Institute of Zoology)

    1992-01-01

    Arsenite, an ubiquitous human carcinogen, has been shown to enhance the cytotoxicity, mutagenicity and clastogenicity of UV light in mammalian cells. Arsenite may exert its co-genotoxic effects by inhibiting DNA repair. Results from alkaline sucrose gradient sedimentation show that arsenite did not accumulate UV-induced DNA strand breaks in Chinese hamster ovary (CHO) K1 cells as aphidicolin plus hydroxyurea (HU) did. These data indicate that arsenite did not inhibit the activity of DNA polymerase [alpha] in UV repair. Treatment with arsenite before UV irradiation slightly reduced the DNA strand breaks accumulated by cytosine [beta]-D-arabinofuranoside (AraC) plus HU. This effect implies that arsenite only slightly inhibited the incision of UV-induced DNA adducts. The low molecular weight DNA accumulated by post-UV incubation with AraC plus HU shifted to high molecular weight upon the incubation of cells in drug-free medium, but this shifting was prohibited by the presence of arsenite. This suggests that arsenite inhibited the rejoining of DNA strand breaks. When a pulse-chase labelling procedure was applied on UV-irradiated cells, the chain elongation of nascent DNA was strongly inhibited by post-incubation with arsenite. These data show that arsenite inhibited post-replication repair in UV-irradiated cells. Therefore, the steps inhibited by arsenite in UV-induced cells. Therefore, the steps inhibited by arsenite in UV-induced DNA repair in CHO K1 cells are different from human fibroblasts. (author).

  12. Effect of arsenite on the DNA repair of UV-irradiated Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Lee-Chen, S.F.; Yu, C.T.; Jan, K.Y.

    1992-01-01

    Arsenite, an ubiquitous human carcinogen, has been shown to enhance the cytotoxicity, mutagenicity and clastogenicity of UV light in mammalian cells. Arsenite may exert its co-genotoxic effects by inhibiting DNA repair. Results from alkaline sucrose gradient sedimentation show that arsenite did not accumulate UV-induced DNA strand breaks in Chinese hamster ovary (CHO) K1 cells as aphidicolin plus hydroxyurea (HU) did. These data indicate that arsenite did not inhibit the activity of DNA polymerase α in UV repair. Treatment with arsenite before UV irradiation slightly reduced the DNA strand breaks accumulated by cytosine β-D-arabinofuranoside (AraC) plus HU. This effect implies that arsenite only slightly inhibited the incision of UV-induced DNA adducts. The low molecular weight DNA accumulated by post-UV incubation with AraC plus HU shifted to high molecular weight upon the incubation of cells in drug-free medium, but this shifting was prohibited by the presence of arsenite. This suggests that arsenite inhibited the rejoining of DNA strand breaks. When a pulse-chase labelling procedure was applied on UV-irradiated cells, the chain elongation of nascent DNA was strongly inhibited by post-incubation with arsenite. These data show that arsenite inhibited post-replication repair in UV-irradiated cells. Therefore, the steps inhibited by arsenite in UV-induced cells. Therefore, the steps inhibited by arsenite in UV-induced DNA repair in CHO K1 cells are different from human fibroblasts. (author)

  13. Receiver function estimated by maximum entropy deconvolution

    Institute of Scientific and Technical Information of China (English)

    吴庆举; 田小波; 张乃铃; 李卫平; 曾融生

    2003-01-01

    Maximum entropy deconvolution is presented to estimate receiver function, with the maximum entropy as the rule to determine auto-correlation and cross-correlation functions. The Toeplitz equation and Levinson algorithm are used to calculate the iterative formula of error-predicting filter, and receiver function is then estimated. During extrapolation, reflective coefficient is always less than 1, which keeps maximum entropy deconvolution stable. The maximum entropy of the data outside window increases the resolution of receiver function. Both synthetic and real seismograms show that maximum entropy deconvolution is an effective method to measure receiver function in time-domain.

  14. Urban UV environment in a sub-tropical megacity – A measurement and modelling study

    Directory of Open Access Journals (Sweden)

    Ka-Ming Wai

    Full Text Available The variations of solar total UV (UVA + UVB exposure rates in a megacity featured with high-rise buildings during summer months were measured and relevant model predictions were evaluated. The maximum pedestrian-level total solar UV exposure rate was less than the un-obstructed exposure rate at any time, attributing to the prevailing reduction in the diffuse solar radiation due to the obstruction effects of distant buildings. Comparing with the measurements, our coupled model well captured the spatial and temporal variations of the reduction of UV exposure rates. By measurements, large reduction in the solar total UV exposure rate down to 12% of un-obstructed exposure rate due to the building obstruction effects was found, agreeing with our previous simulation results and results from an Australian megacity. On the other hand, building reflection from reflective curtain walls could reach 23% of the un-obstructed solar total UV exposure rate at the ground level. This implied improper building design creating additional harmful effects of solar UV radiation on the environment. The coupled model was also applied to predict the urban UV exposure rates during a tropical-cyclone induced aerosol episode. A well-evaluated urban solar UV model is an important tool for sustainable urban design.

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

    Science.gov (United States)

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

    2012-02-01

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

  16. Operational indicators

    International Nuclear Information System (INIS)

    2010-01-01

    The chapter presents the operational indicators related to budget, travel costs and tickets, the evolution of the annual program for regulatory inspection, the scientific production, requested patents and the numbers related to the production of the services offered by the Institution

  17. Maximum Power from a Solar Panel

    Directory of Open Access Journals (Sweden)

    Michael Miller

    2010-01-01

    Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  19. Optical and UV-Aging Properties of LDH-Modified Bitumen

    Directory of Open Access Journals (Sweden)

    Xing Liu

    2015-07-01

    Full Text Available Layered double hydroxides (LDHs are an ultraviolet-light (UV resistant material. In this study, LDHs were used to modify bitumen. The optical and UV aging properties of LDHs modified bitumen were investigated. Firstly, the thin films of bitumen, with and without LDHs, were prepared. By using the UV-Vis spectrophotometer, absorbance, reflectance, and transmittance of bituminous thin film were evaluated. The morphology of LDHs-modified bitumen was observed by using fluorescence microscopy (FM. Finally, the aging resistance of LDH-modified bitumen was investigated by using the UV-aging oven. Results indicated that the LDHs, especially with 5 wt % in the bitumen, can effectively absorb and reflect the UV light and improve the UV-aging resistance of bitumen. This implied that the addition of LDHs into bitumen had the potential to prolong the service life of asphalt pavement.

  20. UV-induced carbon monoxide emission from sand and living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2012-01-01

    The global burden of carbon monoxide, CO, is rather uncertain. In this paper we address the potential of UV-induced CO emission by terrestrial surfaces. Real-time measurements of [CO] were made with a cavity enhanced laser connected in closed loop to either an ecosystem chamber or a leaf scale...... chamber. Sand and leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation and the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature, indicating an abiotic process. The emission of CO...... in response to the UV-component of natural solar radiation was also evident at the ecosystem scale. When scaled to the global level, the UV-induced emission of CO by the major types of terrestrial surfaces, living leaves and soil (here represented by sand), amounts up to 28 Tg yr−1. This source has...

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

  3. Amarginal contribution of selected carotenoids to the supression of UV-irradiation-induced lecithin peroxidation in hexane solution

    Directory of Open Access Journals (Sweden)

    DRAGAN CVETKOVIC

    2007-03-01

    Full Text Available The aim of this work was to study the anticipated antioxidant role of four selected carotenoids in mixtures with lecithin lipoidal compounds in hexane solution, under continuous UV-irradiation in three different ranges (UV-A, UV-B and UV-C. Two carotenes (b-carotene and licopene and two xantophylls (lutein and neoxanthin were employed to control the lipid peroxidation process generated by UV-irradiation, by scavenging the involved free radicals. The results show that while carotenoids undergo a substantial, structural dependent destruction (bleaching, which is highly dependent on energy of the UV-photons, their contribution to the expected suppression of lecithin peroxidation is of marginal importance, not exceeding a maximum of 20%. The marginal antioxidant behaviour has been attributed to a highly unordered hexane solution, where the scavenging action of the carotenoids becomes less competitive.

  4. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  5. The evolutionary response of plants to increased UV-B radiation: Field studies with Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Trumbull, V.L.; Paige, K.N.

    1995-01-01

    The response of a species to any environmental change is determined by both phenotypic and evolutionary adjustments. To date, the majority of research concerning the response of terrestrial plants to increased UV-B radiation has focused on phenotypic adjustments. Recently we have initiated field studies aimed at assessing genetic variation for UV-B sensitivity within a natural population of Arabidopsis thaliana. This population consists of at least eight discrete genotypes that have been confirmed by RAPD analysis. We used an incomplete block design to assess the impact of UV-B (ambient and ambient + 6 kJ) and PAR (low and high) on these genotypes. The high UV-B treatment caused a significant reduction in fruit number and plant height while the high PAR treatment caused a significant increase in these variables. In addition, there was a marginally significant (p=0.1) UV-B x PAR x maternal line interaction for fruit number, indicating that genetic variation for UV-B sensitivity within this population depends on the PAR environment. The combination of high UV-B and high PAR caused a change in fruit number (relative to the ambient UV-B/high PAR treatment) ranging from an increase of 24% to a decrease of 47%. This range was much smaller in the low PAR treatment. These results indicate the potential for increased UV-B radiation to act as an agent of natural selection within this population

  6. Presence of UV-endonuclease sensitive sites in daughter DNA of UV-irradiated mammalian cells

    International Nuclear Information System (INIS)

    D'Ambrosio, S.; Setlow, R.B.

    1978-02-01

    Asynchronous Chinese hamster cells were irradiated with 10 Jm -2 uv radiation and 0.25 to 4 hours later pulse-labeled with [ 3 H]thymidine. Cells synchronized by shaking off mitotic and G 1 cells were irradiated in either the G 1 -phase or S-phase of the cell cycle and pulse-labeled with [ 3 H]thymidine in the S-phase. After a 12 to 14 hour chase in unlabeled medium, the DNA was extracted, incubated with Micrococcus luteus uv-endonuclease and sedimented in alkaline sucrose. The number of endonuclease sensitive sites decreased as the time between uv irradiation and pulse-labeling of daughter DNA increased. Further, there were significantly less endonuclease sensitive sites in the daughter DNA from cells irradiated in the G 1 -phase than in the S-phase. These data indicate that very few, if any, dimers are transferred from parental DNA to daughter DNA and that the dimers detected in daughter DNA may be due to the irradiation of replicating daughter DNA before labeling

  7. Effect of excess ozone on UV-stimulated tritium oxidation

    International Nuclear Information System (INIS)

    Hasegawa, Kiyoshi; Horii, Kazuhiro; Matsuyama, Masao; Watanabe, Kuniaki.

    1995-01-01

    The authors have reported that the oxidation of tritium is considerably accelerated by irradiating a mixture gas of HT(H 2 )-O 2 with UV-photons, and this UV-stimulated HT oxidation is mainly due to the formation of intermediates such as ozone and activated oxygen species. This suggests that the oxidation will be much more enhanced in the presence of excess ozone in the reaction system. To examine this possibility, effects of the excess ozone on the UV-stimulated HT oxidation was experimentally studied on the one hand, and reaction mechanisms were investigated by developing a computer simulation program applicable to the three-component system of HT(H 2 )-O 2 -O 3 . The formation rate of HTO was measured for gas mixtures consisting of O 2 (75.5 Torr), O 3 (0.5-2% of O 2 ), H 2 (0.1-3% of O 2 ) and HT(H 2 /HT=12000). The experiments showed considerable enhancement of the HTO production rate in the presence of excess ozone by UV-photons from a low pressure mercury lamp(5W). The time course of the reaction was reproduced quite well by computer simulation, indicating that the assumed reaction mechanism is valid. This is also supported by observations that computer simulation reproduced the experimentally observed dependence of ozone decomposition rate on ozone and hydrogen pressures under the UV-irradiation. Those results showed that UV-stimulated HT oxidation was accelerated by about 14000 times in the presence of excess ozone. It strongly suggests that the UV-stimulated oxidation in the presence of excess ozone will be applicable to tritium handling systems as a non-catalytic tritium removal method. (author)

  8. UV Tanning Equipment | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

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

  9. UV B-induced vertical migrations of cyanobacteria in a microbial mat

    International Nuclear Information System (INIS)

    Rebout, B.M.; Garcia-Pichel, F.

    1995-01-01

    Exposure to moderate doses of UV B (0.35 to 0.79 W m -2 s -1 or 0.98 to 2.2 μmol of photons m -2 s -1 at 310 nm) caused the surface layers of microbial mats from Solar Lake, Sinai, Egypt, to become visibly lighter green. Concurrent with the color change were rapid and dramatic reductions in gross photosynthesis and in the resultant high porewater oxygen concentrations in the surface layers of the mats. The depths at which both maximum gross photosynthesis and maximum oxygen concentrations occurred were displaced downward. In contrast, gross photosynthesis in the deeper layers of the mats increased in response to UV B incident upon the surface. The cessation of exposure to UV B partially reversed all of these changes. Taken together, these responses suggest that photoautotrophic members of the mat community, most likely the dominant cyanobacterium Microcoleus chthonoplastes, were migrating in response to the added UV B. The migration phenomenon was also observed in response to increases in visible radiation and UV A, but UV B was ca. 100-fold more effective than visible radiation and ca. 20-fold more effective than UV A in provoking the response. Migrating microorganisms within this mat are apparently able to sense UV B directly and respond behaviorally to limit their exposure to UV. Because of strong vertical gradients of light and dissolved substances in microbial mats, the migration and the resultant vertical redistribution of photosynthetic activity have important consequences for both the photobiology of the cyanobacteria and the net primary productivity of the mat ecosystem

  10. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  11. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ren, Hongqiang, E-mail: hqren@nju.edu.cn; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L{sup −1}. The transformation kinetic data for ARGs removal (log C{sub 0} / C) followed the second-order reaction kinetic model with FC dosage (R{sup 2} = 0.6829–0.9999) and contact time (R{sup 2} = 0.7353–8634), respectively. Higher ammonia nitrogen (NH{sub 3}–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl{sub 2}:NH{sub 3}–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm{sup −2}, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - Highlights: • Chlorine is more effective than UV irradiation in removing ARGs from MWTP effluent. • The chlorination reaction followed the second-order reaction kinetic model. • Higher NH{sub 3}–N contents result in lower ARGs removal in the chlorination process. • FC is more effective than CC on the inactivation of ARGs. • UV irradiation followed by chlorination shows high efficiency in removing ARGs.

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  13. Oxidation by-products and ecotoxicity assessment during the photodegradation of fenofibric acid in aqueous solution with UV and UV/H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, Javier [Department of Chemical Engineering, University of Alcala, E-28771 Alcala de Henares (Spain); Agueera, Ana; Mar Gomez-Ramos, Maria del [Department of Analytical Chemistry, University of Almeria, E-04010 Almeria (Spain); Fernandez Alba, Amadeo R. [Department of Analytical Chemistry, University of Almeria, E-04010 Almeria (Spain); Advanced Study Institute of Madrid, IMDEA-Agua, Parque Cientifico Tecnologico, E-28805 Alcala de Henares, Madrid (Spain); Garcia-Calvo, Eloy [Department of Chemical Engineering, University of Alcala, E-28771 Alcala de Henares (Spain); Advanced Study Institute of Madrid, IMDEA-Agua, Parque Cientifico Tecnologico, E-28805 Alcala de Henares, Madrid (Spain); Rosal, Roberto, E-mail: roberto.rosal@uah.es [Department of Chemical Engineering, University of Alcala, E-28771 Alcala de Henares (Spain); Advanced Study Institute of Madrid, IMDEA-Agua, Parque Cientifico Tecnologico, E-28805 Alcala de Henares, Madrid (Spain)

    2011-10-30

    Highlights: {yields} UV and UV/H{sub 2}O{sub 2} photolysis of fenofibric acid. {yields} Identification of reaction intermediates using exact mass measurements. {yields} UV/H{sub 2}O{sub 2} removed toxicity towards Pseudokirchneriella subcapitata. {yields} Irradiated samples contain a number of chlorinated products. - Abstract: The degradation of an aqueous solution of fenofibric acid was investigated using ultraviolet (UV) photolysis and UV/H{sub 2}O{sub 2} with a low-pressure mercury lamp. We obtained quantum yields at different temperatures and the rate constant for the reaction of fenofibric acid with hydroxyl radicals. The maximum radical exposure per fluence ratio obtained was 1.4 x 10{sup -10} M L{sup -1} mW{sup -1}. Several reaction intermediates were detected by means of exact mass measurements performed by liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (LC-ESI-QTOF-MS). UV and UV/H{sub 2}O{sub 2} pathways involve the decarboxylation of fenofibric acid to 4-chloro-4'-(1-hydroxy-1-methylethyl)benzophenone and other minor products, predominantly chlorinated aromatics. We detected several intermediates from reactions with hydroxyl radicals and some lower molecular weight products from the scission of the carbonyl carbon-to-aromatic-carbon bond. We recorded high toxicity in UV irradiated samples for the growth of Pseudokirchneriella subcapitata even after the total depletion of fenofibric acid; this was probably due to the presence of chlorinated aromatics. A degree of toxicity reappeared in highly irradiated UV/H{sub 2}O{sub 2} samples, probably because of the formation of ring-opening products. The degree of mineralization was closely related to that of dechlorination and reached values of over 50% after 3-4 min before stabilizing thereafter.

  14. Enhancement of growth, photosynthetic performance and yield by exclusion of ambient UV components in C3 and C4 plants.

    Science.gov (United States)

    Kataria, Sunita; Guruprasad, K N; Ahuja, Sumedha; Singh, Bupinder

    2013-10-05

    A field experiment was conducted under tropical climate for assessing the effect of ambient UV-B and UV-A by exclusion of UV components on the growth, photosynthetic performance and yield of C3 (cotton, wheat) and C4 (amaranthus, sorghum) plants. The plants were grown in specially designed UV exclusion chambers, wrapped with filters that excluded UV-B (plant species responded to UV exclusion by a significant increase in plant height, leaf area, leaf biomass, total biomass accumulation and yield. Measurements of the chlorophyll, chlorophyll fluorescence parameters, gas exchange parameters and the activity of Ribulose-1,5-bisphosphate carboxylase (Rubisco) by fixation of (14)CO2 indicated a direct relationship between enhanced rate of photosynthesis and yield of the plants. Quantum yield of electron transport was enhanced by the exclusion of UV indicating better utilization of PAR assimilation and enhancement in reducing power in all the four plant species. Exclusion of UV-B in particular significantly enhanced the net photosynthetic rate, stomatal conductance and activity of Rubisco. Additional fixation of carbon due to exclusion of ambient UV-B was channeled towards yield as there was a decrease in the level of UV-B absorbing substances and an increase in soluble proteins in all the four plant species. The magnitude of the promotion in all the parameters studied was higher in dicots (cotton, amaranthus) compared to monocots (wheat, sorghum) after UV exclusion. The results indicated a suppressive action of ambient UV-B on growth and photosynthesis; dicots were more sensitive than monocots in this suppression while no great difference in sensitivity was found between C3 and C4 plants. Experiments indicated the suppressive action of ambient UV on carbon fixation and yield of C3 and C4 plants. Exclusion of solar UV-B will have agricultural benefits in both C3 and C4 plants under tropical climate. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Maximum vehicle cabin temperatures under different meteorological conditions

    Science.gov (United States)

    Grundstein, Andrew; Meentemeyer, Vernon; Dowd, John

    2009-05-01

    A variety of studies have documented the dangerously high temperatures that may occur within the passenger compartment (cabin) of cars under clear sky conditions, even at relatively low ambient air temperatures. Our study, however, is the first to examine cabin temperatures under variable weather conditions. It uses a unique maximum vehicle cabin temperature dataset in conjunction with directly comparable ambient air temperature, solar radiation, and cloud cover data collected from April through August 2007 in Athens, GA. Maximum cabin temperatures, ranging from 41-76°C, varied considerably depending on the weather conditions and the time of year. Clear days had the highest cabin temperatures, with average values of 68°C in the summer and 61°C in the spring. Cloudy days in both the spring and summer were on average approximately 10°C cooler. Our findings indicate that even on cloudy days with lower ambient air temperatures, vehicle cabin temperatures may reach deadly levels. Additionally, two predictive models of maximum daily vehicle cabin temperatures were developed using commonly available meteorological data. One model uses maximum ambient air temperature and average daily solar radiation while the other uses cloud cover percentage as a surrogate for solar radiation. From these models, two maximum vehicle cabin temperature indices were developed to assess the level of danger. The models and indices may be useful for forecasting hazardous conditions, promoting public awareness, and to estimate past cabin temperatures for use in forensic analyses.

  16. UV Observations of Atomic Oxygen in the Cusp Region

    Science.gov (United States)

    Fritz, B.; Lessard, M.; Dymond, K.; Kenward, D. R.; Lynch, K. A.; Clemmons, J. H.; Hecht, J. H.; Hysell, D. L.; Crowley, G.

    2017-12-01

    The Rocket Experiment for Neutral Upwelling (RENU) 2 launched into the dayside cusp on 13 December, 2015. The sounding rocket payload carried a comprehensive suite of particle, field, and remote sensing instruments to characterize the thermosphere in a region where pockets of enhanced neutral density have been detected [Lühr et al, 2004]. An ultraviolet photomultiplier tube (UV PMT) was oriented to look along the magnetic field line and remotely detect neutral atomic oxygen (OI) above the payload. The UV PMT measured a clear enhancement as the payload descended through a poleward moving auroral form, an indicator of structure in both altitude and latitude. Context for the UV PMT measurement is provided by the Special Sensor Ultraviolet Imager (SSULI) instrument on the Defense Meteorological Space Program (DMSP) satellite, which also measured OI as it passed through the cusp. UV tomography of SSULI observations produces a two-dimensional cross-section of volumetric emission rates in the high-latitude thermosphere prior to the RENU 2 flight. The volume emission rate may then be inverted to produce a profile of neutral density in the thermosphere. A similar technique is used to interpret the UV PMT measurement and determine structure in the thermosphere as RENU 2 descended through the cusp.

  17. Role of cyclobutane dimers in UV-denaturation of DNA

    International Nuclear Information System (INIS)

    Zavil'gel'skij, G.B.; Zuev, A.V.

    1978-01-01

    UV irradiation of double-stranded DNA produces local denatured regions. The evidence presented indicates that these single-stranded regions arise from photoproducts other than pyrimidine dimers. The irradiation of T2 DNA at 8x10 4 erg/mm 2 (254 nm) produces 6-8% thymine dimers, amd Tsub(mel) drops by 12-14 deg C, accompanied by a significant broadening of the transition profile. The kinetics of denatured region formation and lowering Tsub(mel) corresponds to that of formation of crosslinkages and differs markedly from the kinetics of formation of cyclobutane pyrimidine dimers. Treatment of UV-irradiated DNA with light in the presence of yeast photoreactivating enzyme monomerizes almost all thymine dimers but does not change the Tsub(mel). Local denatured regions are detected in UV-irradiated DNA and are absent from AcPhM-sensibilized DNA, which contains 20-25% thymine dimers, as determined by the accridine orange fluorescence technique. S1 nuclease from Aspergillis oryzae produces single-strand breaks in UV-irradiated DNA of phage PM2 but is not active on AcPhM-treated PM2 DNA, which contains about 50 thymine dimers. It is supposed that the formation of a cyclobutane dimer only weakens the hydrogen bonds in the AT base pair rather than breaks them. Local denatured regions are thought to arise from the accumulation in UV-irradiated DNA (254 nm) of the sufficient number of photoproducts with impaired ability to base pairing

  18. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

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

    Science.gov (United States)

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

    2008-06-01

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

  20. Studies on Coloration and UV Protective Action of Anar Peel (Pomegranate Rind) as an Effective Natural Colorant for Cotton Khadi Fabric

    Science.gov (United States)

    Sinnur, H. D.; Samanta, Ashis Kumar; Verma, D. K.; Kaware, Runali

    2017-10-01

    Besides optimization of conditions of colour extraction from dried anar peel, effect of different single and double mordants, dyeing process variables and UV protective action of anar peels (pomegranate rind i.e. Punica granatum L.) as a natural colourant is studied in this work. Mordants used are potash alum, aluminium sulphate and stannous chloride (as metallic salt mordant) and harda (i.e., myrobolan as natural mordant) from natural source. Relevant results indicate that 50:50 ratio of harda plus potash aluminium sulphate at overall 15% application level offers maximum K/S value and overall good colour fastness than any other combination. After finalizing the mordants, dyeing process variables were studied for standardization of conditions for dyeing cotton khadi fabric with aqueous extract of pomegranate rind. The results indicate that standardized conditions for dyeing are (a) dyeing time : 60 min, (b) dyeing temperature: 80 °C, (c) dye bath MLR : 1:30, (d) dye bath pH : 9.0, (e) max dye concentration : 20% and (f) common salt : 3%. Studies of FTIR, UV scan, Atomic Absorption Spectrophotometry (AAS) and UV Protection Factor (UPF) characters show a medium to good level of ultraviolet protection. Corresponding reaction mechanism amongst mordant/fibre and dye forming giant complex is also reported.

  1. Studies on Coloration and UV Protective Action of Anar Peel (Pomegranate Rind) as an Effective Natural Colorant for Cotton Khadi Fabric

    Science.gov (United States)

    Sinnur, H. D.; Samanta, Ashis Kumar; Verma, D. K.; Kaware, Runali

    2018-06-01

    Besides optimization of conditions of colour extraction from dried anar peel, effect of different single and double mordants, dyeing process variables and UV protective action of anar peels (pomegranate rind i.e. Punica granatum L.) as a natural colourant is studied in this work. Mordants used are potash alum, aluminium sulphate and stannous chloride (as metallic salt mordant) and harda (i.e., myrobolan as natural mordant) from natural source. Relevant results indicate that 50:50 ratio of harda plus potash aluminium sulphate at overall 15% application level offers maximum K/S value and overall good colour fastness than any other combination. After finalizing the mordants, dyeing process variables were studied for standardization of conditions for dyeing cotton khadi fabric with aqueous extract of pomegranate rind. The results indicate that standardized conditions for dyeing are (a) dyeing time : 60 min, (b) dyeing temperature: 80 °C, (c) dye bath MLR : 1:30, (d) dye bath pH : 9.0, (e) max dye concentration : 20% and (f) common salt : 3%. Studies of FTIR, UV scan, Atomic Absorption Spectrophotometry (AAS) and UV Protection Factor (UPF) characters show a medium to good level of ultraviolet protection. Corresponding reaction mechanism amongst mordant/fibre and dye forming giant complex is also reported.

  2. UV-enhanced reactivation of minute-virus-of-mice: stimulation of a late step in the viral life cycle

    International Nuclear Information System (INIS)

    Rommelaere, J.; Vos, J.-M.; Cornelis, J.J.

    1981-01-01

    UV-enhanced reactivation of minute-virus-of-mice (MVM), an autonomous parvovirus, was studied in parasynchronous mouse A9 cells. The survival of UV-irradiated MVM is increased in cells which have been UV-irradiated prior to infection. UV-enhanced reactivation can be explained neither by facilitated plaque detection on UV-treated indicator cells, nor by altered kinetics of virus production by UV-irradiated cells. No effect of the multiplicity of infection on virus survival was detected in unirradiated or irradiated cells. The magnitude of UV-enhanced reactivation is a direct exponential function of the UV dose administered to the virus while virus survival is inversely proportional to the UV dosage. The expression of UV-enhanced reactivation can be activated in cells arrested in G 0 , it requires de novo protein synthesis and it is maximal when cells are irradiated 30 h before the onset of viral DNA replication. Early phases of the viral cycle, such as adsorption to cellular receptors, migration to the nucleus and uncoating were not affected by cell irradiation and are unlikely targets of the UV-enhanced reactivation function(s). These results, together with the single-strandedness of the viral genome, strongly suggest that the step stimulated in UV-irradiated cells functions concomitant with, or subsequent to, viral DNA replication. (author)

  3. Removal of Acid Red 14 from Contaminated Water Using UV/S2O82- Advanced Oxidation Process

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Rasoulifard

    2012-10-01

    Full Text Available The present study investigates the degradation of Acid Red 14 (AR14, commonly used as a textile dye in aqueous medium through the oxidation process by UV /S2O82- under a set of variables concentration of S2O82-, Ag+, AR14 and temperature. Commonly Ag+, heat and UV light can excite S2O82− to sulfate radical form (SO4−•, a stronger oxidant (E0 = 2.60 V than S2O82−, to enhance significantly the oxidation of contaminants. Also the changes in the absorption spectra of AR14 solutions during the photoxidation process showed that decrease of absorption peak of the dye at λmax = 514 nm indicates a rapid degradation of the azo dye. The results of this study suggest that the oxidative treatment of AR14 by peroxydisulfate with UV is a viable option for removal of the textile dyes from effluents.

  4. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  5. Maximum mass of magnetic white dwarfs

    International Nuclear Information System (INIS)

    Paret, Daryel Manreza; Horvath, Jorge Ernesto; Martínez, Aurora Perez

    2015-01-01

    We revisit the problem of the maximum masses of magnetized white dwarfs (WDs). The impact of a strong magnetic field on the structure equations is addressed. The pressures become anisotropic due to the presence of the magnetic field and split into parallel and perpendicular components. We first construct stable solutions of the Tolman-Oppenheimer-Volkoff equations for parallel pressures and find that physical solutions vanish for the perpendicular pressure when B ≳ 10 13 G. This fact establishes an upper bound for a magnetic field and the stability of the configurations in the (quasi) spherical approximation. Our findings also indicate that it is not possible to obtain stable magnetized WDs with super-Chandrasekhar masses because the values of the magnetic field needed for them are higher than this bound. To proceed into the anisotropic regime, we can apply results for structure equations appropriate for a cylindrical metric with anisotropic pressures that were derived in our previous work. From the solutions of the structure equations in cylindrical symmetry we have confirmed the same bound for B ∼ 10 13 G, since beyond this value no physical solutions are possible. Our tentative conclusion is that massive WDs with masses well beyond the Chandrasekhar limit do not constitute stable solutions and should not exist. (paper)

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

    Science.gov (United States)

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

    2011-02-01

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

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

    International Nuclear Information System (INIS)

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

    1996-01-01

    A combination of field and labotatory studies were conducted to explore the nature of photomorphogenic effects of ultraviolet-B radiation (UV-B; 280–320 nm) on plant morphology and to evaluate the ecological consequences of these alterations in morphology for interspecific competition. Under laboratory conditions, seedlings of cucumber (Cucumis sativus L.) and tomato (Lycopersicon esculentum Mill.) exhibited appreciable (ca. 50%) and rapid (< 3h) inhibition in hypocotyl elongation in response to UV-B exposure. In cucumber, this inhibition was reversible, occurred without any associated changes in dry matter production and was caused by UV-B incident on the cotyledons and not the stem or growing tip. Inhibition of stem elongation in etiolated tomato seedlings occurred at least 3 h prior to the onset of accumulation of UV-absorbing pigments and monochromatic UV supplied against a background of visible radiation revealed maximum effectiveness in inhibition around 300 nm. Collectively, these findings suggest that a specific, but yet unidentified, UV-B photoreceptor is involved in mediating certain morphological responses to UV-B. For mixtures of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.), a common weedy competitor, supplemental UV-B irradiation in the field differentially altered shoot morphology which resulted in changes in canopy structure, light interception and calculated stand photosynthesis. It is argued that, because of its asymmetrical nature, competition for light can potentially amplify the effects of UV-B on shoot morphology and may, therefore, be an important mechanism by which changes in the solar UV-B spectrum associated with stratospheric ozone reduction could alter the composition and character of terrestrial vegetation

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

    Science.gov (United States)

    Singh, Jaswant; Singh, Rudra P

    2014-01-01

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

  9. Evaluation of corneal symmetry after UV corneal crosslinking for keratoconus

    Directory of Open Access Journals (Sweden)

    Mofty H

    2017-11-01

    Full Text Available Hanan Mofty,1,2 Khaled Alzahrani,2 Fiona Carley,3 Sophie Harper,3 Arun Brahma,3 Leon Au,3 Debbie Morley,3 M Chantal Hillarby2 1Optometry Department, College of Applied Medical Science, King Saud University, Riyadh, Kingdom of Saudi Arabia; 2Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3Manchester Royal Eye Hospital, Manchester, UK Purpose: The purpose of this study was to assess UV corneal crosslinking (CXL treatment outcomes for keratoconus by evaluating the corneal regularity in patients through follow-up using the Oculus Pentacam.Patients and methods: A total of 18 eyes from CXL patients with keratoconus were studied before and after CXL treatment, and six eyes from six patients who were not treated with CXL served as controls. Treated patients had Pentacam images taken before CXL treatment and regularly 3 months post treatment up to the 12th month. Controls were imaged during their first appointment and after 12 months. Symmetry and asphericity were evaluated and correlated with both best-corrected visual acuity (BCVA and maximum K-readings.Results: In the CXL-treated group, there was a significant improvement in the index of symmetrical variation (ISV and keratoconus index (KI at 3 months and in the index of height asymmetry (IHA and minimum radius of curvature (Rmin at 9 months post treatment. On the contrary, the untreated group’s indices showed some significant worsening in ISV, KI, central keratoconus index (CKI, and Rmin. A novel finding in our study was a slight positive shift of anterior asphericity in the 6 mm, 7 mm, and 8 mm 3 months after treatment, which had a correlation with BCVA (R2=0.390, p=0.053 and a strong correlation with maximum K-reading (R2=0.690, p=0.005. However, the untreated group had no significant changes after 1 year.Conclusion: The corneal asymmetrical shape is associated with the spherical aberration alteration

  10. Hydroxycinnamic acid derivatives in an aquatic liverwort as possible bioindicators of enhanced UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Arroniz-Crespo, M.; Nunez-Olivera, E. [Universidad de La Rioja, Complejo Cientifico-Tecnologico, Avda. Madre de Dios 51, 26006 Logrono (La Rioja) (Spain); Martinez-Abaigar, J. [Universidad de La Rioja, Complejo Cientifico-Tecnologico, Avda. Madre de Dios 51, 26006 Logrono (La Rioja) (Spain)], E-mail: javier.martinez@unirioja.es

    2008-01-15

    We examined, under laboratory conditions, the physiological responses of the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia to artificially enhanced ultraviolet (UV) radiation for 82 days, especially considering the responses of five hydroxycinnamic acid derivatives. This species lives in mountain streams, where it is exposed to low temperatures and high UV levels, and this combination is believed to increase the adverse effects of UV. Enhanced UV radiation hardly caused any change in several physiological variables indicative of vitality, such as F{sub v}/F{sub m} and chlorophylls/phaeopigments ratio (OD430/OD410). Thus, this liverwort seemed to be tolerant to UV radiation, probably due to the accumulation of three UV-absorbing hydroxycinnamic acid derivatives: p-coumaroylmalic acid, 5''-(7'',8''-dihydroxycoumaroyl)-2-caffeoylmalic acid, and 5''-(7'',8''-dihydroxy-7-O-{beta}-glucosyl-coumaroyl)-2-caffeoylmalic acid. These compounds might serve as bioindicators of enhanced UV radiation. - Several hydroxycinnamic acid derivatives of an aquatic liverwort are induced by enhanced UV radiation and might serve as bioindicators of changes in UV levels.

  11. UV-B effects on crops: response of the irrigated rice ecosystem

    International Nuclear Information System (INIS)

    Olszyk, D.; Dai, Q.; Teng, P.; Leung, H.; Luo, Y.; Peng, S.

    1996-01-01

    Increasing ultraviolet-B (UV-B) radiation resulting from depletion of the stratospheric ozone layer could have damaging effects on crops. This paper reviews recent findings on direct effects of UV-B on rice growth and yield as well as indirect effects via impacts on other organisms in the rice (Oryza sativa) agroecosystem. The findings are based on research by scientists at the International Rice Research Institute (IRRI) in Los Baños, the Philippines, and their collaborators in China and the United States; with comparison to research by scientists in other countries. Current results indicate that while enhanced UV-B directly impacts many aspects of rice growth, physiology, and biochemistry under controlled phytotron conditions; in general rice growth and yield are not affected under natural field conditions. The difference in response may be related both to the levels of UV-B exposure used in phytotron vs. field studies and the lower ratio of UV-A to UV-B in the phytotron compared to field. In terms of indirect effects on rice blast disease, enhanced UV-B affected both the fungus itself (Pyricularia grisea) and the susceptibility of the rice plant to the fungus. Based on these data, simulation models estimated potential impacts of higher UV-B levels on blast severity and rice yield in different countries of southeast and east Asia. Ultimately, results from rice studies can be used to identify strategies to minimize any negative effects of UV-B on rice productivity

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  14. Revealing the Maximum Strength in Nanotwinned Copper

    DEFF Research Database (Denmark)

    Lu, L.; Chen, X.; Huang, Xiaoxu

    2009-01-01

    boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...

  15. Modelling maximum canopy conductance and transpiration in ...

    African Journals Online (AJOL)

    There is much current interest in predicting the maximum amount of water that can be transpired by Eucalyptus trees. It is possible that industrial waste water may be applied as irrigation water to eucalypts and it is important to predict the maximum transpiration rates of these plantations in an attempt to dispose of this ...

  16. Seismic Device UVS 1504, possibilities of its Utilization

    Directory of Open Access Journals (Sweden)

    Leššo Igor

    1996-09-01

    Full Text Available Department of Mining and Geotechnics for many years deals with questions of the technical seismicity. In the paper are given possibilities of utilizing the UVS 1504 device and results obtained from the measurement of seismic effects of blasting as well as others sources of bursts. The measurements showed that this device enables to measure parameters and to evaluate measured data quickly, reliably, and with a very high precision. The device enables evaluating individual time degrees of blasts, determining the law of attenuation of the seismic waves, and precise determination of the maximum charge permissible for futher advance of the blasting in given conditions.

  17. COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

    Directory of Open Access Journals (Sweden)

    О. Міхєєв

    2011-04-01

    Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

  18. UV-absorbing compounds in subarctic herbarium bryophytes

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen, S. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)]. E-mail: satu.huttunen@oulu.fi; Lappalainen, N.M. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland); Turunen, J. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)

    2005-01-01

    The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A{sub 280-320nm}) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time.

  19. UV-absorbing compounds in subarctic herbarium bryophytes

    International Nuclear Information System (INIS)

    Huttunen, S.; Lappalainen, N.M.; Turunen, J.

    2005-01-01

    The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A 280-320nm ) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time

  20. Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation

    Science.gov (United States)

    Sato, Tomohiro O.; Sato, Takao M.; Sagawa, Hideo; Noguchi, Katsuyuki; Saitoh, Naoko; Irie, Hitoshi; Kita, Kazuyuki; Mahani, Mona E.; Zettsu, Koji; Imasu, Ryoichi; Hayashida, Sachiko; Kasai, Yasuko

    2018-03-01

    We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area) and two observation times (one during summer and one during winter) were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT), middle troposphere (MT), and lowermost troposphere (LMT) were estimated using the degree of freedom for signal (DFS), the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU), respectively. The DFS value was increased by approximately 96, 23, and 30 % by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone; nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding constraints

  1. Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation

    Directory of Open Access Journals (Sweden)

    T. O. Sato

    2018-03-01

    Full Text Available We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV, thermal infrared (TIR, and microwave (MW ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area and two observation times (one during summer and one during winter were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT, middle troposphere (MT, and lowermost troposphere (LMT were estimated using the degree of freedom for signal (DFS, the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM, and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU, respectively. The DFS value was increased by approximately 96, 23, and 30 % by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone; nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding

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

    Science.gov (United States)

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

    2018-01-01

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

  3. CALIBRATING UV STAR FORMATION RATES FOR DWARF GALAXIES FROM STARBIRDS

    Energy Technology Data Exchange (ETDEWEB)

    McQuinn, Kristen B. W.; Skillman, Evan D.; Mitchell, Noah P. [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street, S.E., Minneapolis, MN 55455 (United States); Dolphin, Andrew E., E-mail: kmcquinn@astro.umn.edu [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States)

    2015-08-01

    Integrating our knowledge of star formation (SF) traced by observations at different wavelengths is essential for correctly interpreting and comparing SF activity in a variety of systems and environments. This study compares extinction corrected integrated ultraviolet (UV) emission from resolved galaxies with color–magnitude diagram (CMD) based star formation rates (SFRs) derived from resolved stellar populations and CMD fitting techniques in 19 nearby starburst and post-starburst dwarf galaxies. The data sets are from the panchromatic Starburst Irregular Dwarf Survey and include deep legacy GALEX UV imaging, Hubble Space Telescope optical imaging, and Spitzer MIPS imaging. For the majority of the sample, the integrated near-UV fluxes predicted from the CMD-based SFRs—using four different models—agree with the measured, extinction corrected, integrated near-UV fluxes from GALEX images, but the far-UV (FUV) predicted fluxes do not. Furthermore, we find a systematic deviation between the SFRs based on integrated FUV luminosities and existing scaling relations, and the SFRs based on the resolved stellar populations. This offset is not driven by different SF timescales, variations in SFRs, UV attenuation, nor stochastic effects. This first comparison between CMD-based SFRs and an integrated FUV emission SFR indicator suggests that the most likely cause of the discrepancy is the theoretical FUV–SFR calibration from stellar evolutionary libraries and/or stellar atmospheric models. We present an empirical calibration of the FUV-based SFR relation for dwarf galaxies, with uncertainties, which is ∼53% larger than previous relations.

  4. Maximum entropy deconvolution of low count nuclear medicine images

    International Nuclear Information System (INIS)

    McGrath, D.M.

    1998-12-01

    Maximum entropy is applied to the problem of deconvolving nuclear medicine images, with special consideration for very low count data. The physics of the formation of scintigraphic images is described, illustrating the phenomena which degrade planar estimates of the tracer distribution. Various techniques which are used to restore these images are reviewed, outlining the relative merits of each. The development and theoretical justification of maximum entropy as an image processing technique is discussed. Maximum entropy is then applied to the problem of planar deconvolution, highlighting the question of the choice of error parameters for low count data. A novel iterative version of the algorithm is suggested which allows the errors to be estimated from the predicted Poisson mean values. This method is shown to produce the exact results predicted by combining Poisson statistics and a Bayesian interpretation of the maximum entropy approach. A facility for total count preservation has also been incorporated, leading to improved quantification. In order to evaluate this iterative maximum entropy technique, two comparable methods, Wiener filtering and a novel Bayesian maximum likelihood expectation maximisation technique, were implemented. The comparison of results obtained indicated that this maximum entropy approach may produce equivalent or better measures of image quality than the compared methods, depending upon the accuracy of the system model used. The novel Bayesian maximum likelihood expectation maximisation technique was shown to be preferable over many existing maximum a posteriori methods due to its simplicity of implementation. A single parameter is required to define the Bayesian prior, which suppresses noise in the solution and may reduce the processing time substantially. Finally, maximum entropy deconvolution was applied as a pre-processing step in single photon emission computed tomography reconstruction of low count data. Higher contrast results were

  5. Air quality indicators

    International Nuclear Information System (INIS)

    Clench-Aas, Jocelyn; Guerreiro, Cristina; Bartonova, Alena

    1999-06-01

    This report proposes and describes in detail several air quality indicators that may be used to describe population exposure. The suggested indicators account for temporal and spatial patterns of pollution and movements of individuals between different micro-environments. The Air Quality Indicator /AQI) should represent both the spatial and temporal aspects of pollution exposure that may have important effects on health. Two indicators are needed, the Population Air Quality Indicator and the Individual Air Quality Indicator. Mean concentrations, 98th percentile and maximum values are the traditional indicators for estimating exposure. the temporal variability of PM-10 and NO 2 , however, is here described by means of: 1) The rate of change of pollution as the difference between two consecutive hourly values and of 2) episodes, described in terms of number, duration and winter episode period, maximum concentration in the episode and integrated episode exposure (episode AOT50/100). The spatial variation of AQIs can be described in several ways, e.g.: 1) Concentrations in neighbouring grid squares can be compared as an indication of spatial variation and 2) point estimates can be compared to grid values for a description of variation within a grid. Both methods are presented here. A test of the representativity of static point estimates for pollution exposure is to compare them to an estimate of air pollution exposure accounting for movements between different locations, obtained using diaries. The ultimate aim of AQIs is to describe the population exposure to ambient pollution. This is done by estimating the number of people exposed using different characteristics of AQIs. The data used to describe these indicators originates from dispersion modelling of short-term air pollution concentrations in Oslo. Two series of data are used. One represents hour-for hour concentrations in the 1 km 2 grid system covering the city of Oslo, winter 1994/95, calculated by the grid

  6. Discontinuity of maximum entropy inference and quantum phase transitions

    International Nuclear Information System (INIS)

    Chen, Jianxin; Ji, Zhengfeng; Yu, Nengkun; Zeng, Bei; Li, Chi-Kwong; Poon, Yiu-Tung; Shen, Yi; Zhou, Duanlu

    2015-01-01

    In this paper, we discuss the connection between two genuinely quantum phenomena—the discontinuity of quantum maximum entropy inference and quantum phase transitions at zero temperature. It is shown that the discontinuity of the maximum entropy inference of local observable measurements signals the non-local type of transitions, where local density matrices of the ground state change smoothly at the transition point. We then propose to use the quantum conditional mutual information of the ground state as an indicator to detect the discontinuity and the non-local type of quantum phase transitions in the thermodynamic limit. (paper)

  7. A Maximum Entropy Method for a Robust Portfolio Problem

    Directory of Open Access Journals (Sweden)

    Yingying Xu

    2014-06-01

    Full Text Available We propose a continuous maximum entropy method to investigate the robustoptimal portfolio selection problem for the market with transaction costs and dividends.This robust model aims to maximize the worst-case portfolio return in the case that allof asset returns lie within some prescribed intervals. A numerical optimal solution tothe problem is obtained by using a continuous maximum entropy method. Furthermore,some numerical experiments indicate that the robust model in this paper can result in betterportfolio performance than a classical mean-variance model.

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

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  9. UV lamp for photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Cardoso, M.J.B.; Landers, R.; Sundaram, V.S.

    1983-01-01

    An UV lamp and a differential pumping system which enables to couple the lamp to an ultra-high vacuum chamber (10 -9 torr) without using windows, are described. The differential between the pressure inside the discharge chamber and the one in de UHV region, which is of 10 8 -10 9 , is achieved with two pumping states separated by pyrex capillaries having an internal diameter of 0.6 mm. In the first stage, a mechanical pump (10 -3 torr) is used; in the second stage, a diffusor pump with a cryogenic trap (N 2 liq - 10 -7 torr) is employed. The lamp produces, when used with high purity He, narrow lines almost clear at 21.2 eV and 40.8 eV, depending on the discharge chamber pressure, thus eliminating the need of a monochromator. As a high voltage source (3 KV), a commercial unit with a good current control was used, ensuring UV beam stability - an essential characteristic for this lamp if it is employed for photoelectron excitation of crystalline samples. (C.L.B.) [pt

  10. MXLKID: a maximum likelihood parameter identifier

    International Nuclear Information System (INIS)

    Gavel, D.T.

    1980-07-01

    MXLKID (MaXimum LiKelihood IDentifier) is a computer program designed to identify unknown parameters in a nonlinear dynamic system. Using noisy measurement data from the system, the maximum likelihood identifier computes a likelihood function (LF). Identification of system parameters is accomplished by maximizing the LF with respect to the parameters. The main body of this report briefly summarizes the maximum likelihood technique and gives instructions and examples for running the MXLKID program. MXLKID is implemented LRLTRAN on the CDC7600 computer at LLNL. A detailed mathematical description of the algorithm is given in the appendices. 24 figures, 6 tables

  11. Efficiency of ocular UV protection by clear lenses.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Stege, H; Mang, R

    2006-05-01

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

  13. Medical UV exposures and HIV activation

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  14. Generation and characterization of antigenic variants induced by exposure of tumor cells to UV radiation in vitro

    International Nuclear Information System (INIS)

    Hostetler, L.L.W.

    1988-01-01

    Antigenic changes present in nonantigenic tumor cells exposed to UV radiation (UV) in vitro were investigated by addressing the following questions: (1) Are antigenic variants (AV) produced that are rejected in normal but not immunosuppressed mice? (2) Does generation of AV depend upon intrinsic properties of the cells exposed or result from the action of UV? (3) Is antigenic modification induced by UV due to increased histocompatibility antigen expression? (4) Do AV crossreact immunologically with parental tumor or with other AV? and (5) Is the UV-associated common antigen expressed on UV-induced tumors present on UV-irradiated tumor cells? AV were generated at different frequencies following in vitro UV irradiation of a spontaneous murine fibrosarcoma, a murine melanoma, and two melanoma clones. Immunological experiments demonstrated that the AV and parental cells shared a determinant that was susceptible to immune recognition, but incapable of inducing immunity. In contrast, the AV were noncrossreactive, suggesting that variant-specific antigens were also expressed. Finally, the AV were recognized by UV-induced suppressor cells, indicating that the UV-associated common antigen expressed by UV-induced tumors was also present

  15. UV-Induced Cell Death in Plants

    Science.gov (United States)

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

    2013-01-01

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

  16. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

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

  17. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  18. Maximum neutron flux in thermal reactors

    International Nuclear Information System (INIS)

    Strugar, P.V.

    1968-12-01

    Direct approach to the problem is to calculate spatial distribution of fuel concentration if the reactor core directly using the condition of maximum neutron flux and comply with thermal limitations. This paper proved that the problem can be solved by applying the variational calculus, i.e. by using the maximum principle of Pontryagin. Mathematical model of reactor core is based on the two-group neutron diffusion theory with some simplifications which make it appropriate from maximum principle point of view. Here applied theory of maximum principle are suitable for application. The solution of optimum distribution of fuel concentration in the reactor core is obtained in explicit analytical form. The reactor critical dimensions are roots of a system of nonlinear equations and verification of optimum conditions can be done only for specific examples

  19. Maximum allowable load on wheeled mobile manipulators

    International Nuclear Information System (INIS)

    Habibnejad Korayem, M.; Ghariblu, H.

    2003-01-01

    This paper develops a computational technique for finding the maximum allowable load of mobile manipulator during a given trajectory. The maximum allowable loads which can be achieved by a mobile manipulator during a given trajectory are limited by the number of factors; probably the dynamic properties of mobile base and mounted manipulator, their actuator limitations and additional constraints applied to resolving the redundancy are the most important factors. To resolve extra D.O.F introduced by the base mobility, additional constraint functions are proposed directly in the task space of mobile manipulator. Finally, in two numerical examples involving a two-link planar manipulator mounted on a differentially driven mobile base, application of the method to determining maximum allowable load is verified. The simulation results demonstrates the maximum allowable load on a desired trajectory has not a unique value and directly depends on the additional constraint functions which applies to resolve the motion redundancy

  20. Maximum phytoplankton concentrations in the sea

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas

    2008-01-01

    A simplification of plankton dynamics using coagulation theory provides predictions of the maximum algal concentration sustainable in aquatic systems. These predictions have previously been tested successfully against results from iron fertilization experiments. We extend the test to data collect...

  1. Quality, precision and accuracy of the maximum No. 40 anemometer

    Energy Technology Data Exchange (ETDEWEB)

    Obermeir, J. [Otech Engineering, Davis, CA (United States); Blittersdorf, D. [NRG Systems Inc., Hinesburg, VT (United States)

    1996-12-31

    This paper synthesizes available calibration data for the Maximum No. 40 anemometer. Despite its long history in the wind industry, controversy surrounds the choice of transfer function for this anemometer. Many users are unaware that recent changes in default transfer functions in data loggers are producing output wind speed differences as large as 7.6%. Comparison of two calibration methods used for large samples of Maximum No. 40 anemometers shows a consistent difference of 4.6% in output speeds. This difference is significantly larger than estimated uncertainty levels. Testing, initially performed to investigate related issues, reveals that Gill and Maximum cup anemometers change their calibration transfer functions significantly when calibrated in the open atmosphere compared with calibration in a laminar wind tunnel. This indicates that atmospheric turbulence changes the calibration transfer function of cup anemometers. These results call into question the suitability of standard wind tunnel calibration testing for cup anemometers. 6 refs., 10 figs., 4 tabs.

  2. Maximum-Likelihood Detection Of Noncoherent CPM

    Science.gov (United States)

    Divsalar, Dariush; Simon, Marvin K.

    1993-01-01

    Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.

  3. The UV Survey Mission Concept, CETUS

    Science.gov (United States)

    Heap, Sara; and the CETUS Team

    2018-01-01

    In March 2017, NASA selected CETUS for study of a Probe-class mission concept. W. Danchi is the CETUS PI, and S. Heap is the Science PI. CETUS is primarily a UV survey telescope to complement survey telescopes of the 2020’s including E-ROSITA, Subaru Hyper Suprime Cam and Prime-Focus Spectrograph, WFIRST, and the Square Kilometer Array. CETUS comprises a 1.5-m wide-field telescope and three science instruments: a wide-field (1045” on a side) far-UV and near-UV camera; a similarly wide-field near-UV multi-object spectrograph utilizing a next-generation micro-shutter array; and a single-object spectrograph with options of spectral region (far-UV or near-UV) and spectral resolving power (2,000 or 40,000). The survey instruments will operate simultaneously thereby producing wide-field images in the near-UV and far-UV and a spectrogram containing near-UV spectra of up to 100 sources free of spectral overlap and astronomical background. ln concert with other survey telescopes, CETUS will focus on understanding galaxy evolution at cosmic noon (z~1-2).

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

    Science.gov (United States)

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

    2017-04-01

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

  5. New technologies for UV detectors

    Science.gov (United States)

    Joseph, C. L.

    1993-01-01

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

  6. Photodegradation of pharmaceuticals in the aquatic environment by sunlight and UV-A, -B and -C irradiation.

    Science.gov (United States)

    Kawabata, Kohei; Sugihara, Kazumi; Sanoh, Seigo; Kitamura, Shigeyuki; Ohta, Shigeru

    2013-01-01

    In order to investigate the effect of sunlight on the persistence and ecotoxicity of pharmaceuticals contaminating the aquatic environment, we exposed nine pharmaceuticals (acetaminophen (AA), amiodarone (AM), dapsone (DP), dexamethasone (DX), indomethacin (IM), naproxen (NP), phenytoin (PH), raloxifene (RL), and sulindac (SL)) in aqueous media to sunlight and to ultraviolet (UV) irradiation at 254, 302 or 365 nm (UV-C, UV-B or UV-A, respectively). Degradation of the pharmaceuticals was monitored by means of high-performance liquid chromatography (HPLC). Sunlight completely degraded AM, DP and DX within 6 hr, and partly degraded the other pharmaceuticals, except AA and PH, which were not degraded. Similar results were obtained with UV-B, while UV-A was less effective (both UV-A and -B are components of sunlight). All the pharmaceuticals were photodegraded by UV-C, which is used for sterilization in sewage treatment plants. Thus, the photodegradation rates of pharmaceuticals are dependent on both chemical structure and the wavelength of UV exposure. Toxicity assay using the luminescent bacteria test (ISO11348) indicated that UV irradiation reduced the toxicity of some pharmaceuticals to aquatic organisms by decreasing their amount (photodegradation) and increased the toxicity of others by generating toxic photoproduct(s). These results indicate the importance of investigating not only parent compounds, but also photoproducts in the risk assessment of pharmaceuticals in aquatic environments.

  7. MicroRNA-22 promotes cell survival upon UV radiation by repressing PTEN

    International Nuclear Information System (INIS)

    Tan, Guangyun; Shi, Yuling; Wu, Zhao-Hui

    2012-01-01

    Highlights: ► miR-22 is induced in cells treated with UV radiation. ► ATM is required for miR-22 induction in response to UV. ► miR-22 targets 3′-UTR of PTEN to repress its expression in UV-treated cells. ► Upregulated miR-22 inhibits apoptosis in cells exposed to UV. -- Abstract: DNA damage response upon UV radiation involves a complex network of cellular events required for maintaining the homeostasis and restoring genomic stability of the cells. As a new class of players involved in DNA damage response, the regulation and function of microRNAs in response to UV remain poorly understood. Here we show that UV radiation induces a significant increase of miR-22 expression, which appears to be dependent on the activation of DNA damage responding kinase ATM (ataxia telangiectasia mutated). Increased miR-22 expression may result from enhanced miR-22 maturation in cells exposed to UV. We further found that tumor suppressor gene phosphatase and tensin homolog (PTEN) expression was inversely correlated with miR-22 induction and UV-induced PTEN repression was attenuated by overexpression of a miR-22 inhibitor. Moreover, increased miR-22 expression significantly inhibited the activation of caspase signaling cascade, leading to enhanced cell survival upon UV radiation. Collectively, these results indicate that miR-22 is an important player in the cellular stress response upon UV radiation, which may promote cell survival via the repression of PTEN expression.

  8. Genetic study of resistance to inhibitory effects of UV radiation in rice (Oryza sativa)

    International Nuclear Information System (INIS)

    Sato, T.; Kang, H.S.; Kumagai, T.

    1994-01-01

    Genetic analysis of resistance to the inhibitory effects of UV radiation on growth of rice (Oryza sativa L.) cultivars was carried out. Some experimental plants were grown in visible radiation supplemented with UV radiation containing a large amount of UV-B and a small amount of UV-C in a phytotron, while others were grown without UV radiation. The degree of resistance to UV radiation was estimated in terms of the degree of reduction caused by supplemental UV radiation in the fresh weight of the aboveground plant parts and the chlorophyll content per unit fresh weight. Fresh weight and chlorophyll content in F 2 plants generated by reciprocally crossing cv. Sasanishiki, a cultivar more resistant to UV radiation, and Norin 1, a cultivar less resistant to such radiation exhibited a normal frequency distribution. The heritabilities of these two properties in F 2 plants were low under conditions of non-supplemental UV radiation. Under elevated UV radiation, the F 2 population shifted to the lower range of fresh weight and chlorophyll content, and the means were close to those of Norin 1. The heritabilities of these two properties were the same in the reciprocal crosses, indicating that maternal inheritance was not involved. Inheritance of chlorophyll content per unit fresh weight was further determined in F 3 lines generated by self-fertilizing F 2 plants of Sasanishiki and Norin 1. The results showed that the F 3 population was segregated into three genotypes, namely, resistant homozygotes, segregated heterozygotes and sensitive homozygotes, with a ratio of 1:65:16. It was thus evident that the resistance to the inhibitory effect of elevated UV radiation in these rice plants was controlled by recessive polygenes. (author)

  9. Degradation of chloramphenicol by UV/chlorine treatment: Kinetics, mechanism and enhanced formation of halonitromethanes.

    Science.gov (United States)

    Dong, Huiyu; Qiang, Zhimin; Hu, Jun; Qu, Jiuhui

    2017-09-15

    Ultraviolet (UV)/chlorine process is considered as an emerging advanced oxidation process for the degradation of micropollutants. This study investigated the degradation of chloramphenicol (CAP) and formation of disinfection by-products (DBPs) during the UV/chlorine treatment. It was found that CAP degradation was enhanced by combined UV/chlorine treatment compared to that of UV and chlorination treatment alone. The pseudo-first-order rate constant of the UV/chlorine process at pH 7.0 reached 0.016 s -1 , which was 10.0 and 2.0 folds that observed from UV and chlorination alone, respectively. The enhancement can be attributed to the formation of diverse radicals (HO and reactive chlorine species (RCSs)), and the contribution of RCSs maintained more stable than that of HO at pH 5.5-8.5. Meanwhile, enhanced DBPs formation during the UV/chlorine treatment was observed. Both the simultaneous formation and 24-h halonitromethanes formation potential (HNMsFP) were positively correlated with the UV/chlorine treatment time. Although the simultaneous trichloronitromethane (TCNM) formation decreased with the prolonged UV irradiation, TCNM dominated the formation of HNMs after 24 h (>97.0%). According to structural analysis of transformation by-products, both the accelerated CAP degradation and enhanced HNMs formation steps were proposed. Overall, the formation of diverse radicals during the UV/chlorine treatment accelerated the degradation of CAP, while also enhanced the formation of DBPs simultaneously, indicating the need for DBPs evaluation before the application of combined UV/chlorine process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Inactivation of microorganisms by UV-treatment of must and wine

    Directory of Open Access Journals (Sweden)

    Durner Dominik

    2017-01-01

    Full Text Available The objective was to investigate the applicability of UV-C technology to inactivate yeasts and bacteria in must and wine. Experiments were carried out in vintage 2016 with Riesling musts of different quality containing their natural microflora. Yeasts were tested more resistant to UV-C energy than bacteria. Saccharomyces cerevisiae showed higher tolerance against UV-C irradiation than Hanseniaspora uvarum facilitating new opportunities to control spontaneous fermentations. However, inactivation efficacy was strongly dependent on turbidity of musts and the initial degree of contamination suggesting a shadowing effect of individual germs. Compared with thermal pasteurization, UV-C treatment of must with 1 kJ/L showed similar effects in germ-reduction. While thermal pasteurization significantly decreased aroma precursors in musts, UV-C treatment did not change concentrations of glycosidically-bound C6-alcohols, monoterpenes and C13-norisoprenoids as shown by GC-MS analysis. Applying UV-C technology in wines, it was possible to irreversibly stop ongoing alcoholic fermentation indicating that UV-C treatment is capable to replace SO2 addition to produce wines with residual sugar. Besides inactivation power, UV-C is known for its ability to form powerful off-flavours such as methional or methanethiol. Sensory analysis revealed that the application of UV-C at doses < 2 kJ/L in must is uncritical. However, applying UV-C after alcoholic fermentation can result in rising concentrations of mercaptans already at doses < 1 kJ/L. In this context, compounds such as caftaric acid, riboflavin and dissolved oxygen are thought to positively contribute to the UV-induced formation of off-flavours in wine.

  11. UV-extending Ghost Inflation

    CERN Document Server

    Ivanov, Mikhail M

    2014-01-01

    We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether theory or its khronometric version. Compared to previous works on ghost inflation our setup allows to go beyond the study of small perturbations and include the background dynamics in a unified framework. In the specific regime when the expansion of the Universe is dominated by the kinetic energy of the inflaton we find that the model predicts rather high tensor-to-scalar ratio r ~ 0.02 $\\div$ 0.2 and non-Gaussianity of equilateral type with f_NL in the range from -50 to -5.

  12. LED-based UV source for monitoring spectroradiometer properties

    Science.gov (United States)

    Sildoja, Meelis-Mait; Nevas, Saulius; Kouremeti, Natalia; Gröbner, Julian; Pape, Sven; Pendsa, Stefan; Sperfeld, Peter; Kemus, Fabian

    2018-06-01

    A compact and stable UV monitoring source based on state-of-the-art commercially available ultraviolet light emitting diodes (UV-LEDs) has been developed. It is designed to trace the radiometric stability—both responsivity and wavelength scale—of array spectroradiometers measuring direct solar irradiance in the wavelength range between 300 nm and 400 nm. The spectral irradiance stability of the UV-LED-based light source observed in the laboratory after seasoning (burning-in) the individual LEDs was better than 0.3% over a 12 h period of continuous operation. The integral irradiance measurements of the source over a period of several months, where the UV-LED source was not operated continuously between the measurements, showed stability within 0.3%. In-field measurements of the source with an array spectroradiometer indicated the stability of the source to be within the standard uncertainty of the spectroradiometer calibration, which was within 1% to 2%.

  13. UV stimulation of DNA-mediated transformation of human cells

    International Nuclear Information System (INIS)

    van Duin, M.; Westerveld, A.; Hoeijmakers, J.H.

    1985-01-01

    Irradiation of dominant marker DNA with UV light (150 to 1,000 J/m2) was found to stimulate the transformation of human cells by this marker from two- to more than fourfold. This phenomenon is also displayed by xeroderma pigmentosum cells, which are deficient in the excision repair of UV-induced pyrimidine dimers in the DNA. Also, exposure to UV of the transfected (xeroderma pigmentosum) cells enhanced the transfection efficiency. Removal of the pyrimidine dimers from the DNA by photoreactivating enzyme before transfection completely abolished the stimulatory effect, indicating that dimer lesions are mainly responsible for the observed enhancement. A similar stimulation of the transformation efficiency is exerted by 2-acetoxy-2-acetylaminofluorene modification of the DNA. These findings suggest that lesions which are targets for the excision repair pathway induce the increase in transformation frequency. The stimulation was found to be independent of sequence homology between the irradiated DNA and the host chromosomal DNA. Therefore, the increase of the transformation frequency is not caused by a mechanism inducing homologous recombination between these two DNAs. UV treatment of DNA before transfection did not have a significant effect on the amount of DNA integrated into the xeroderma pigmentosum genome

  14. Investigation of the mechanisms by which UV irradiation activates the tyrosinase gene

    International Nuclear Information System (INIS)

    Bao, Y.

    2000-04-01

    Tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2) are the enzymes involved in melanin pigment synthesis. They are expressed specifically in melanocytic cells. UV irradiation is the major physiological stimulant of melanogenesis. Tyrosinase is the rate-limiting enzyme in melanin synthesis and its activity is regulated by UV irradiation in melanocytes. The molecular mechanism underlying the activation of tyrosinase by UV is still not clear. In this thesis, the effects of UV irradiation on tyrosinase, TRP-1 and TRP-2 gene expression in mouse B16 melanoma cells were studied as well as the effects of UV irradiation on the activity of the tyrosinase promoter in mouse, and human melanoma cells. UV irradiation caused an increase in tyrosinase mRNA level, without change in either TRP-1 or TRP-2 mRNA levels, as determined by Northern blot analysis. In order to determine whether UV- induced increase of tyrosinase mRNA expression involved modulation of tyrosinase promoter activity, transient transfection approaches involving a series of constructs containing either chloramphenicol acetyl transferase (CAT) or luciferase reporter genes linked to different lengths of the tyrosinase gene- promoter were used. UV irradiation specifically induced CAT gene expression from both the mouse and the human tyrosinase promoters, suggesting that UV irradiation induced the transcription of the tyrosinase gene. These observations indicated that the promoter region between -250 and -150 bp of the human tyrosinase promoter may contain important cis-regulatory elements involved in the UV response. To localise the cis-regulatory elements responsible for the UV response of the tyrosinase promoter, the 100-bp between -250 bp and -150 bp of the tyrosinase promoter was inserted upstream of a CAT reporter. It was shown that transcription from the 100-bp promoter fragment was activated by UV irradiation. Mutations of a potential cAMP response element (CRE) motif

  15. Flavonoids are systemically induced by UV-B in Zea mays

    International Nuclear Information System (INIS)

    Tossi, V.E.; Lamattina, L.; Cassia, R.

    2009-01-01

    Flavonoid concentration is increased by UV-B irradiation, but it is unknown if this is a local or systemic response. Nitric oxide (NO) is a diffusible molecule involved in the UV-B response. NO regulates the expression of chalcone synthase (CHS), a key enzyme in the synthesis of flavonoids. The aim of this work was to determine if maize flavonoids are local or systemically induced by UV-B, and what is the participation of NO in this response. We have used maize seedlings where the second leaf was sprayed with H 2 O or cPTIO (a NO scavenger), and then completely covered (C), partially covered (P) or uncovered (U) before to be UV-B irradiated. The results show a 60% increase in the NO concentration of U, 42% in P and 35% in C respectively. Flavonoid concentration increased 90% in C, 70% in P and 40% in U. Flavonoid concentration was reduced when leaves were pretreated with cPTIO before the UV-B irradiation. RT-PCR shows that CHS was up-regulated by UV-B in U, P and C, but downregulated with cPTIO. We have analyzed the subcellular localization of flavonoid and NO in UV-B irradiated plants. Flavonoid localization was coincident with the NO presence in the irradiated surface of the leaves and flavonoids were detected in vesicles. These results indicate that flavonoids are systemically induced by UV-B in a NO-related mechanism. (authors)

  16. The protective roles of TiO2 nanoparticles against UV-B toxicity in Daphnia magna.

    Science.gov (United States)

    Liu, Jie; Wang, Wen-Xiong

    2017-09-01

    Aquatic environments are increasingly under environmental stress due to ultraviolet (UV) radiation and potential inputs of nanoparticles with intense application of nanotechnology. In this study, we investigated the interaction between UV-B radiation and titanium nanoparticles (TiO 2 -NPs) in a model freshwater cladoceran Daphnia magna. UV-B toxicity to Daphnia magna was examined when the daphnids were exposed to a range of TiO 2 -NPs concentrations with an initial 5 or 10min of 200μW/cm 2 UV-B radiation. In addition, UV-B toxicity was also examined in the presence of TiO 2 -NPs in the body of daphnids. Our results demonstrated that the daphnid mortality under UV-B radiation decreased significantly in the presence of TiO 2 -NPs both in the water and in the body, indicating that TiO 2 -NPs had some protective effects on D. magna against UV-B. Such protective effect was mainly caused by the blockage of UV-B by TiO 2 -NPs adsorption. UV-B produced reactive oxygen species (ROS) in the water and in the daphnids, which was not sufficient to cause mortality of daphnids over short periods of radiation. Previous studies focused on the effects of TiO 2 -NPs on the toxicity of total UV radiation, and did not attempt to differentiate the potential diverse roles of UV-A and UV-B. Our study indicated that TiO 2 -NPs may conversely protect the UV-B toxicity to daphnids. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  18. UV dichroic coatings on metallic reflectors

    International Nuclear Information System (INIS)

    Raghunath, C; Babu, N J; Chandran, K M

    2008-01-01

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

  19. UV dichroic coatings on metallic reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Raghunath, C; Babu, N J; Chandran, K M [Hind High Vacuum Co. Pvt. Ltd. No.17, Phase 1, Peenya Industrial Area, Bangalore 560058 (India)

    2008-05-01

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

  20. UV Bandpass Optical Filter for Microspectometers

    NARCIS (Netherlands)

    Correia, J.H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in

  1. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

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

  2. Discontinuities during UV writing of waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour.......UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour....

  3. Direct UV-writing of waveguides

    DEFF Research Database (Denmark)

    Færch, Kjartan Ullitz

    2003-01-01

    induced refractive index change of more than 10-2 have been obtained. New insight, with respect to understanding the UV induced index change obtained by direct UV writing, has been provided, through experiments conducted with such high-pressure loaded germanosilica samples. This include measurements...

  4. Effect of UV laser irradiation on tissue

    International Nuclear Information System (INIS)

    Nakayama, Takeyoshi; Kubo, Uichi

    1992-01-01

    Laser-tissue interactions have been investigated through Electron Probe Micro Analysis (EPMA), UV-visible optical absorption and Fourier Transform Infrared Spectroscopy (FTIR). Three excimer lasers, ArF, KrF and XeCl, were used to irradiate tissue; cow thighbone and gelatin thin film. Features of UV laser irradiation are described. (author)

  5. uv photobiology: DNA damage and repair

    International Nuclear Information System (INIS)

    Sutherland, B.M.

    1978-01-01

    The following topics are discussed: targets that determine the fate of the cell when uv light interacts with a cell; comparison of action spectrum for a given biological effect with the absorption spectrum of different biological macromolecules; biological effects of damage to DNA; measurement of mutations; chemical damage to DNA; photoreactivation; role of pyrimidine dimers in induction of skin cancer by uv

  6. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  7. UV Reconstruction Algorithm And Diurnal Cycle Variability

    Science.gov (United States)

    Curylo, Aleksander; Litynska, Zenobia; Krzyscin, Janusz; Bogdanska, Barbara

    2009-03-01

    UV reconstruction is a method of estimation of surface UV with the use of available actinometrical and aerological measurements. UV reconstruction is necessary for the study of long-term UV change. A typical series of UV measurements is not longer than 15 years, which is too short for trend estimation. The essential problem in the reconstruction algorithm is the good parameterization of clouds. In our previous algorithm we used an empirical relation between Cloud Modification Factor (CMF) in global radiation and CMF in UV. The CMF is defined as the ratio between measured and modelled irradiances. Clear sky irradiance was calculated with a solar radiative transfer model. In the proposed algorithm, the time variability of global radiation during the diurnal cycle is used as an additional source of information. For elaborating an improved reconstruction algorithm relevant data from Legionowo [52.4 N, 21.0 E, 96 m a.s.l], Poland were collected with the following instruments: NILU-UV multi channel radiometer, Kipp&Zonen pyranometer, radiosonde profiles of ozone, humidity and temperature. The proposed algorithm has been used for reconstruction of UV at four Polish sites: Mikolajki, Kolobrzeg, Warszawa-Bielany and Zakopane since the early 1960s. Krzyscin's reconstruction of total ozone has been used in the calculations.

  8. Maximum gravitational redshift of white dwarfs

    International Nuclear Information System (INIS)

    Shapiro, S.L.; Teukolsky, S.A.

    1976-01-01

    The stability of uniformly rotating, cold white dwarfs is examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordtvedt. The maximum central density and gravitational redshift of a white dwarf are determined as functions of five of the nine PPN parameters (γ, β, zeta 2 , zeta 3 , and zeta 4 ), the total angular momentum J, and the composition of the star. General relativity predicts that the maximum redshifts is 571 km s -1 for nonrotating carbon and helium dwarfs, but is lower for stars composed of heavier nuclei. Uniform rotation can increase the maximum redshift to 647 km s -1 for carbon stars (the neutronization limit) and to 893 km s -1 for helium stars (the uniform rotation limit). The redshift distribution of a larger sample of white dwarfs may help determine the composition of their cores

  9. EPR and UV spectrometry investigation of sucrose irradiated with carbon particles

    International Nuclear Information System (INIS)

    Karakirova, Yordanka; Yordanov, Nicola D.

    2010-01-01

    Solid state/EPR (SS/EPR) dosimeters of carbon ions irradiated sucrose are studied with EPR, and their water solutions - with UV spectroscopy. Doses between 20 and 200 Gy are used with linear energy transfer (LET) values for carbon ions of 63, 77, 96 and 230 keV μm -1 . After irradiation all samples show typical for irradiated sucrose EPR and UV spectra. The obtained data are compared with those previously reported for nitrogen particles and gamma rays irradiated sucrose. The identical shape of both the EPR and UV spectra of irradiated with various type radiation samples suggests that generated free radicals are not influenced by the nature of radiation. The lack of difference in the line width of the separate lines or the whole EPR spectrum, obtained for gamma and heavy particles irradiation, suggests negligible spin-spin interaction among the radiation-generated free radicals in the samples. The linear dependence of the EPR response on the absorbed dose radiation is found to be higher when generated by gamma rays, than by the same absorbed dose of heavy particles. In addition, the EPR response for carbon ions is higher than that for nitrogen ions. Water solutions of irradiated sucrose exhibit UV spectrum with absorption maximum at 267 nm, attributed to the recombination products of free radicals. The UV band intensity depends on the absorbed dose radiation. The UV spectra obtained for carbon, nitrogen and gamma rays irradiated sucrose are also compared.

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

    Science.gov (United States)

    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.

  11. UV-straling in de kas: mogelijkheden en grenzen

    NARCIS (Netherlands)

    Hoffmann, S.

    2000-01-01

    Effect van UV-straling op kleuring van Coleus Blumei 'Wizzard Velvit Red'. Gegevens in bijgaande tabellen: 1) Indeling optische straling; 2) Transmisse voor UV-straling van verschillende dekmaterialen (folie UV, glas UV, glas normaal, folie normaal, folie UV-blok

  12. UV-induced transcription from the human immunodeficiency virus type 1 (HIV-1) long terminal repeat and UV-induced secretion of an extracellular factor that induces HIV-1 transcription in nonirradiated cells

    International Nuclear Information System (INIS)

    Stein, B.; Kraemer, M.R.; Rahmsdorf, H.J.; Ponta, H.; Herrlich, P.

    1989-01-01

    UV irradiation, but not visible sunlight, induces the transcription of human immunodeficiency virus type 1 (HIV-1). Chimeric constructs carrying all or parts of the HIV-1 long terminal repeat linked to an indicator gene were transfected into HeLa cells or murine and human T-cell lines, and their response to irradiation was tested. The cis-acting element conferring UV responsiveness is identical to the sequence binding transcription factor NF kappa B. UV irradiation enhances NF kappa B binding activity as assayed by gel retardation experiments. Interestingly, the requirement for UV irradiation can be replaced by cocultivation of transfected cells with UV-irradiated nontransfected (HIV-1-negative) cells. A UV-induced extracellular protein factor is detected in the culture medium conditioned by UV-treated cells. The factor is produced upon UV irradiation by several murine and human cell lines, including HeLa, Molt-4, and Jurkat, and acts on several cells. These data suggest that the UV response of keratinocytes in human skin can be magnified and spread to deeper layers that are more shielded, including the Langerhans cells, and that this indirect UV response may contribute to the activation of HIV-1 in humans

  13. Maximum entropy analysis of EGRET data

    DEFF Research Database (Denmark)

    Pohl, M.; Strong, A.W.

    1997-01-01

    EGRET data are usually analysed on the basis of the Maximum-Likelihood method \\cite{ma96} in a search for point sources in excess to a model for the background radiation (e.g. \\cite{hu97}). This method depends strongly on the quality of the background model, and thus may have high systematic unce...... uncertainties in region of strong and uncertain background like the Galactic Center region. Here we show images of such regions obtained by the quantified Maximum-Entropy method. We also discuss a possible further use of MEM in the analysis of problematic regions of the sky....

  14. The Maximum Resource Bin Packing Problem

    DEFF Research Database (Denmark)

    Boyar, J.; Epstein, L.; Favrholdt, L.M.

    2006-01-01

    Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...

  15. Shower maximum detector for SDC calorimetry

    International Nuclear Information System (INIS)

    Ernwein, J.

    1994-01-01

    A prototype for the SDC end-cap (EM) calorimeter complete with a pre-shower and a shower maximum detector was tested in beams of electrons and Π's at CERN by an SDC subsystem group. The prototype was manufactured from scintillator tiles and strips read out with 1 mm diameter wave-length shifting fibers. The design and construction of the shower maximum detector is described, and results of laboratory tests on light yield and performance of the scintillator-fiber system are given. Preliminary results on energy and position measurements with the shower max detector in the test beam are shown. (authors). 4 refs., 5 figs

  16. Topics in Bayesian statistics and maximum entropy

    International Nuclear Information System (INIS)

    Mutihac, R.; Cicuttin, A.; Cerdeira, A.; Stanciulescu, C.

    1998-12-01

    Notions of Bayesian decision theory and maximum entropy methods are reviewed with particular emphasis on probabilistic inference and Bayesian modeling. The axiomatic approach is considered as the best justification of Bayesian analysis and maximum entropy principle applied in natural sciences. Particular emphasis is put on solving the inverse problem in digital image restoration and Bayesian modeling of neural networks. Further topics addressed briefly include language modeling, neutron scattering, multiuser detection and channel equalization in digital communications, genetic information, and Bayesian court decision-making. (author)

  17. Density estimation by maximum quantum entropy

    International Nuclear Information System (INIS)

    Silver, R.N.; Wallstrom, T.; Martz, H.F.

    1993-01-01

    A new Bayesian method for non-parametric density estimation is proposed, based on a mathematical analogy to quantum statistical physics. The mathematical procedure is related to maximum entropy methods for inverse problems and image reconstruction. The information divergence enforces global smoothing toward default models, convexity, positivity, extensivity and normalization. The novel feature is the replacement of classical entropy by quantum entropy, so that local smoothing is enforced by constraints on differential operators. The linear response of the estimate is proportional to the covariance. The hyperparameters are estimated by type-II maximum likelihood (evidence). The method is demonstrated on textbook data sets

  18. Increased UV-B radiation reduces N2-fixation in tropical leguminous crops

    International Nuclear Information System (INIS)

    Anupa Singh

    1997-01-01

    Net photosynthesis, leaf area, biomass, and number, size and activity of nodules were examined in three leguminous plants subjected under field conditions to supplemental UV-B radiation equivalent to a 15% ozone depletion at 25 degrees N latitude. Enhanced UV-B radiation adversely affected the net photosynthetic rate, growth characteristics and nodule activity in all three species. Maximum reduction in net photosynthesis occurred in Phaseolus mungo cv. Pant U-30, whereas the greatest reduction in nitrogenase activity occurred in Vigna radiata. (author)

  19. Ultraviolet radiation exposure from UV-transilluminators.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Jahangir-Blourchian, Mahdi

    2005-10-01

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

  20. UV Reflectance of Jupiter's Moon Europa and Asteroid (16) Psyche

    Science.gov (United States)

    Becker, T. M.; Retherford, K. D.; Roth, L.; Hendrix, A.; McGrath, M. A.; Cunningham, N.; Feaga, L. M.; Saur, J.; Elkins-Tanton, L. T.; Walhund, J. E.; Molyneux, P.

    2017-12-01

    Surface reflectance observations of solar system objects in the UV are not only complimentary to longer wavelength observations for identifying surface composition, but can also reveal new and meaningful information about the surfaces of those bodies. On Europa, far-UV (FUV) spectral observations made by the Hubble Space Telescope (HST) show that the surface lacks a strong water ice absorption edge near 165 nm, which is intriguing because such a band has been detected on most icy satellites. This may suggest that radiolytic processing by Jupiter's magnetosphere has altered the surface, causing absorption at wavelengths longward of the H2O edge, masking this feature. Additionally, the FUV spectra are blue (increasing albedo with shorter wavelengths), and regions that are observed to be dark in the visible appear bright in the FUV. This spectral inversion, also observed on the Moon and some asteroids, may provide insight into the properties of the surface material and how they are processed.We also explore the UV reflectance spectra of the main belt asteroid (16) Psyche. This asteroid is believed to be the metallic remnant core of a differentiated asteroid, stripped of its mantle through collisions. However, there is speculation that the asteroid could have formed as-is from highly reduced metal-rich material near the Sun early in the formation of the solar system. Further, spectral observations in the infrared have revealed pyroxene and hydroxyl on the asteroid's surface, complicating the interpretation that (16) Psyche is a pure metallic object. Laboratory studies indicate that there are diagnostic spectral features in the UV that could be useful for determining the surface composition. We obtained HST observations of Psyche from 160 - 300 nm. Preliminary results show a featureless, red-sloped spectrum, inconsistent with significant amounts of pyroxene on the surface. We will present the spectra of Europa and the asteroid (16) Psyche and discuss the unique details

  1. Definition of Quality Criteria of the Technological Process of Narrow Web UV-Printing

    Directory of Open Access Journals (Sweden)

    Volodymyr Shybanov

    2013-11-01

    Full Text Available The application of Narrow Web UV-flexographic printing has several advantages compared with offset printing. In particular, they are the lack of the operation of water-ink balance setting in the technological process, the ability to print on a wide range of materials and so on. Though the imprint quality is clearly based on standards in offset printing, there are no clearly indicated requirements for Narrow Web UV flexographic printing. The absence of such requirements on quality parameters of the technological process of Narrow Web UV-Printing predetermined conducting its analysis with the help of expert surveys.

  2. Photoreactivation Study of Wastewater Treatment Effluent Disinfected by UV-disinfection for Water Reuse

    International Nuclear Information System (INIS)

    Yoon, C.G.; Jung, K.W.; Ham, J.H.; Jeon, J.H.

    2003-01-01

    Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration of 10~30 MPN/100mL increased to the level of 100 MPN/100mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time

  3. Plant responses to UV-B irradiation are modified by UV-A irradiation

    International Nuclear Information System (INIS)

    Middleton, E.M.; Teramura, A.H.

    1993-01-01

    The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2013-04-01

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

  6. Nonsymmetric entropy and maximum nonsymmetric entropy principle

    International Nuclear Information System (INIS)

    Liu Chengshi

    2009-01-01

    Under the frame of a statistical model, the concept of nonsymmetric entropy which generalizes the concepts of Boltzmann's entropy and Shannon's entropy, is defined. Maximum nonsymmetric entropy principle is proved. Some important distribution laws such as power law, can be derived from this principle naturally. Especially, nonsymmetric entropy is more convenient than other entropy such as Tsallis's entropy in deriving power laws.

  7. Maximum speed of dewetting on a fiber

    NARCIS (Netherlands)

    Chan, Tak Shing; Gueudre, Thomas; Snoeijer, Jacobus Hendrikus

    2011-01-01

    A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. We theoretically investigate this forced wetting transition for axisymmetric menisci on fibers of varying radii. First, we use a matched asymptotic expansion and derive the maximum speed

  8. Maximum potential preventive effect of hip protectors

    NARCIS (Netherlands)

    van Schoor, N.M.; Smit, J.H.; Bouter, L.M.; Veenings, B.; Asma, G.B.; Lips, P.T.A.M.

    2007-01-01

    OBJECTIVES: To estimate the maximum potential preventive effect of hip protectors in older persons living in the community or homes for the elderly. DESIGN: Observational cohort study. SETTING: Emergency departments in the Netherlands. PARTICIPANTS: Hip fracture patients aged 70 and older who

  9. Maximum gain of Yagi-Uda arrays

    DEFF Research Database (Denmark)

    Bojsen, J.H.; Schjær-Jacobsen, Hans; Nilsson, E.

    1971-01-01

    Numerical optimisation techniques have been used to find the maximum gain of some specific parasitic arrays. The gain of an array of infinitely thin, equispaced dipoles loaded with arbitrary reactances has been optimised. The results show that standard travelling-wave design methods are not optimum....... Yagi–Uda arrays with equal and unequal spacing have also been optimised with experimental verification....

  10. correlation between maximum dry density and cohesion

    African Journals Online (AJOL)

    HOD

    represents maximum dry density, signifies plastic limit and is liquid limit. Researchers [6, 7] estimate compaction parameters. Aside from the correlation existing between compaction parameters and other physical quantities there are some other correlations that have been investigated by other researchers. The well-known.

  11. Weak scale from the maximum entropy principle

    Science.gov (United States)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2015-03-01

    The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.

  12. The maximum-entropy method in superspace

    Czech Academy of Sciences Publication Activity Database

    van Smaalen, S.; Palatinus, Lukáš; Schneider, M.

    2003-01-01

    Roč. 59, - (2003), s. 459-469 ISSN 0108-7673 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : maximum-entropy method, * aperiodic crystals * electron density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.558, year: 2003

  13. Achieving maximum sustainable yield in mixed fisheries

    NARCIS (Netherlands)

    Ulrich, Clara; Vermard, Youen; Dolder, Paul J.; Brunel, Thomas; Jardim, Ernesto; Holmes, Steven J.; Kempf, Alexander; Mortensen, Lars O.; Poos, Jan Jaap; Rindorf, Anna

    2017-01-01

    Achieving single species maximum sustainable yield (MSY) in complex and dynamic fisheries targeting multiple species (mixed fisheries) is challenging because achieving the objective for one species may mean missing the objective for another. The North Sea mixed fisheries are a representative example

  14. 5 CFR 534.203 - Maximum stipends.

    Science.gov (United States)

    2010-01-01

    ... maximum stipend established under this section. (e) A trainee at a non-Federal hospital, clinic, or medical or dental laboratory who is assigned to a Federal hospital, clinic, or medical or dental... Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY UNDER OTHER SYSTEMS Student...

  15. Minimal length, Friedmann equations and maximum density

    Energy Technology Data Exchange (ETDEWEB)

    Awad, Adel [Center for Theoretical Physics, British University of Egypt,Sherouk City 11837, P.O. Box 43 (Egypt); Department of Physics, Faculty of Science, Ain Shams University,Cairo, 11566 (Egypt); Ali, Ahmed Farag [Centre for Fundamental Physics, Zewail City of Science and Technology,Sheikh Zayed, 12588, Giza (Egypt); Department of Physics, Faculty of Science, Benha University,Benha, 13518 (Egypt)

    2014-06-16

    Inspired by Jacobson’s thermodynamic approach, Cai et al. have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar-Cai derivation http://dx.doi.org/10.1103/PhysRevD.75.084003 of Friedmann equations to accommodate a general entropy-area law. Studying the resulted Friedmann equations using a specific entropy-area law, which is motivated by the generalized uncertainty principle (GUP), reveals the existence of a maximum energy density closed to Planck density. Allowing for a general continuous pressure p(ρ,a) leads to bounded curvature invariants and a general nonsingular evolution. In this case, the maximum energy density is reached in a finite time and there is no cosmological evolution beyond this point which leaves the big bang singularity inaccessible from a spacetime prospective. The existence of maximum energy density and a general nonsingular evolution is independent of the equation of state and the spacial curvature k. As an example we study the evolution of the equation of state p=ωρ through its phase-space diagram to show the existence of a maximum energy which is reachable in a finite time.

  16. Response of the middle atmosphere to solar UV and dynamical perturbations

    International Nuclear Information System (INIS)

    Chandra, S.

    1989-01-01

    Recent studies of solar UV related changes of ozone and temperature have considerably improved the understanding of the solar UV and ozone relationship in the middle atmosphere on time scales of a solar rotation. These studies have shown that during periods of high solar activity, ozone in the upper stratosphere has a measurable response to changes in the solar UV flux in accordance with theoretical predictions. The problem of measuring solar response of the stratospheric ozone and temperature on time scales of a solar cycle is more difficult. In the altitude range of 2 mb, the model based calculations, based on plausible scenarios of solar UV variation, suggest a change of less than 4 percent in ozone mixing ratio and 1 to 2 K in temperature. The relative response was studied of the middle atmosphere to solar forcing at 155 and 27 day periods as indicated from the spectral analyses of a number of solar indices

  17. Effect of psoralen and near UV on vertebrate cells in culture: comparison of laser with standard lamp

    International Nuclear Information System (INIS)

    Peterson, S.P.; Berns, M.W.

    1978-01-01

    4'-Aminoethyl-4,5',8-trimethylpsoralen, a DNA photoreagent, was used in conjunction with near UV light to modify cell growth and morphology. Since near UV radiation is needed to trigger the photoreactions, various doses of classical and laser near UV light were exposed to cells growing in media containing psoralen. It was found that near UV light caused a reduction in cell viability as indicated by complete inhibition of growth. The specificity of psoralens for nucleic acids was also investigated by using a tritium labeled psoralen derivative and tracing its appearance in different fractions of DNA from treated and untreated cells. (author)

  18. Effect of psoralen and near uv on vertebrate cells in culture: comparison of laser with standard lamp

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, S P; Berns, M W [California Univ., Irvine (USA)

    1978-03-01

    4'-Aminoethyl-4,5',8-trimethylpsoralen, a DNA photoreagent, was used in conjunction with near uv light to modify cell growth and morphology. Since near uv radiation is needed to trigger the photoreactions, various doses of classical and laser near uv light were administerd to cells growing in media containing psoralen. It was found that near uv light caused a reduction in cell viability as indicated by complete inhibition of growth. The specificity of psoralens for nucleic acids was also investigated by using a tritium labeled psoralen derivative and tracing its appearance in different fractions of DNA from treated and untreated cells.

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

    Science.gov (United States)

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

    1992-08-01

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

  20. Roles for the yeast RAD18 and RAD52 DNA repair genes in UV mutagenesis.

    Science.gov (United States)

    Armstrong, J D; Chadee, D N; Kunz, B A

    1994-11-01

    Experimental evidence indicates that although the Saccharomyces cerevisiae RAD18 and RAD52 genes are not required for nucleotide excision repair, they function in the processing of UV-induced DNA damage in yeast. Conflicting statements regarding the UV mutability of strains deleted for RAD18 prompted us to re-examine the influence of RAD18, and RAD52, on UV mutagenesis. To do so, we characterized mutations induced by UV in SUP4-o, a yeast suppressor tRNA gene. SUP4-o was maintained on a plasmid in isogenic strains that either carried one of two different rad18 deletions (rad18 delta) or had RAD52 disrupted. Both rad18 deletions decreased the frequency of UV-induced SUP4-o mutations to levels close to those for spontaneous mutagenesis in the rad18 delta backgrounds, and prevented a net increase in mutant yield. A detailed analysis of mutations isolated after UV irradiation of one of the rad18 delta strains uncovered little evidence of the specificity features typical for UV mutagenesis in the isogenic repair-proficient (RAD) parent (e.g., predominance of G.C-->A.T transitions). Evidently, UV induction of SUP4-o mutations is highly dependent on the RAD18 gene. Compared to the RAD strain, disruption of RAD52 reduced the frequency and yield of UV mutagenesis by about two-thirds. Closer inspection revealed that 80% of this reduction was due to a decrease in the frequency of G.C-->A.T transitions. In addition, there were differences in the distributions and site specificities of single base-pair substitutions. Thus, RAD52 also participates in UV mutagenesis of a plasmid-borne gene in yeast, but to a lesser extent than RAD18.

  1. Photolytic removal of DBPs by medium pressure UV in swimming pool water

    International Nuclear Information System (INIS)

    Hansen, Kamilla M.S.; Zortea, Raissa; Piketty, Aurelia; Vega, Sergio Rodriguez; Andersen, Henrik Rasmus

    2013-01-01

    Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min −1 for chloroform to 0.523 min −1 for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of combined chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m −3 d −1 and the UV dose required to removed 90% of trichloronitromethane was 0.4 kWh m −3 d −1 , while 2.6 kWh m −3 d −1 was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1 kWh m −3 d −1 . It was predicted thus that a beneficial side-effect of applying UV for removing combined chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes. - Highlights: ► UV irradiation is able to degrade all 12 investigated disinfection by-products. ► Bromine species are easier to remove than their chlorinated analogues. ► UV dose used for combined chlorine was comparable with doses required for DBP removal. ► Significant removal of some disinfection by-products in swimming pools is indicated

  2. Low-level laser irradiation protects the chick embryo chorioallantoic membrane from UV cytotoxicity

    Directory of Open Access Journals (Sweden)

    Hammami Amira

    2018-01-01

    Full Text Available Low-level laser therapy or photobiomodulation is the medical use of a very low intensity light in the red to near infrared (wavelengths in the range of 630-940 nm. The present work was conducted to explore the effects of both UV and low-level laser irradiation (LLLI on microcirculation using the in vivo model of the chick embryo chorioallantoic membrane (CAM. The effects were assessed by measuring lipid peroxidation and antioxidant enzyme activity. Cell cytotoxicity, survival and intracellular reactive oxygen species (ROS of the CAM were also evaluated. We found that UV irradiation induced alterations of the vessels, leading to bleeding and extravasation. This effect was intensified after 60 min of exposure to UV irradiation, leading to marked edema. UVA irradiation increased cell cytotoxicity as assessed by lactate dehydrogenase (LDH release (56.23% of control and reduced cell viability as assessed by decreased fluorescein diacetate (FDA fluorescence (56.23% of control. Pretreatment with LLLI prior to UV exposure protected the CAM tissue from UV-mediated cell death. This protective effect was supported by the observation of significantly inhibited lipid peroxidation (from 0.3±0.004 for UV, to 0.177±0.012 after LLLI pretreatment, ROS and O2 -production, as indicated by respective dihydrorhodamine (DHR and dihydroethidium (DHE intensities (from 132.78% of control for UVA, to 95.90% of control for L-UV (DHR, and from 127.34% of control for UVA, to 82.03% of control for L-UV (DHE, and by preventing the increase in oxidative activities. LLLI efficiently protected CAM cells from UV-induced oxidative stress and appeared as a safe protective pretreatment against UV irradiation.

  3. Retrieval of Surface Ozone from UV-MFRSR Irradiances using Deep Learning

    Science.gov (United States)

    Chen, M.; Sun, Z.; Davis, J.; Zempila, M.; Liu, C.; Gao, W.

    2017-12-01

    High concentration of surface ozone is harmful to humans and plants. USDA UV-B Monitoring and Research Program (UVMRP) uses Ultraviolet (UV) version of Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR) to measure direct, diffuse, and total irradiances every three minutes at seven UV channels (i.e. 300, 305, 311, 317, 325, 332, and 368 nm channels with 2 nm full width at half maximum). Based on the wavelength dependency of aerosol optical depths, there have been plenty of literatures exploring retrieval methods of total column ozone from UV-MFRSR measurements. However, few has explored the retrieval of surface ozone. The total column ozone is the integral of the multiplication of ozone concentration (varying by height and time) and cross section (varying by wavelength and temperature) over height. Because of the distinctive values of ozone cross section in the UV region, the irradiances at seven UV channels have the potential to resolve the ozone concentration at multiple vertical layers. If the UV irradiances at multiple time points are considered together, the uncertainty or the vertical resolution of ozone concentrations can be further improved. In this study, the surface ozone amounts at the UVMRP station located at Billings, Oklahoma are estimated from the adjacent (i.e. within 200 miles) US Environmental Protection Agency (EPA) surface ozone observations using the spatial analysis technique. Then, the (direct normal) irradiances of UVMRP at one or more time points as inputs and the corresponding estimated surface ozone from EPA as outputs are fed into a pre-trained (dense) deep neural network (DNN) to explore the hidden non-linear relationship between them. This process could improve our understanding of their physical/mathematical relationship. Finally, the optimized DNN is tested with the preserved 5% of the dataset, which are not used during training, to verify the relationship.

  4. Radioactive decontamination through UV laser

    International Nuclear Information System (INIS)

    Delaporte, Ph.; Gastaud, M.; Sentis, M.; Uteza, O.; Marine, W.; Thouvenot, P.; Alcaraz, J.L.; Le Samedy, J.M.; Blin, D.

    2003-01-01

    A device allowing the radioactive decontamination of metal surfaces through the use of a pulsed UV laser has been designed and tested. This device is composed of a 1 kW excimer laser linked to a bundle of optic fibers and of a system to recover particles and can operate in active zones. Metal surfaces have the peculiarities to trap radio-elements in a superficial layer of oxide that can be eaten away by laser radiation. Different contaminated metals (stainless steels, INCONEL and aluminium) issued from the nuclear industry have been used for the testing. The most important contaminants were 60 Co, 137 Cs, 154-155 Eu and 125 Sb. The ratio of decontamination was generally of 10 and the volume of secondary wastes generating during the process was very low compared with other decontamination techniques. A decontamination speed of 1 m 2 /h has been reached for aluminium. The state of the surface is an important parameter because radio-elements trapped in micro-cracks are very difficult to remove. (A.C.)

  5. 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.

    Science.gov (United States)

    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.

  6. UV-C irradiation disrupts platelet surface disulfide bonds and activates the platelet integrin alphaIIbbeta3

    NARCIS (Netherlands)

    Verhaar, Robin; Dekkers, David W. C.; de Cuyper, Iris M.; Ginsberg, Mark H.; de Korte, Dirk; Verhoeven, Arthur J.

    2008-01-01

    UV-C irradiation has been shown to be effective for pathogen reduction in platelet concentrates, but preliminary work indicated that UV-C irradiation of platelets can induce platelet aggregation. In this study, the mechanism underlying this phenomenon was investigated. Irradiation of platelets with

  7. Photochemical degradation of chromophoric-dissolved organic matter exposed to simulated UV-B and natural solar radiation

    NARCIS (Netherlands)

    Zhang, Y.; Liu, M.; Qin, B.; Feng, S.

    2009-01-01

    Photochemical degradation of chromophoric-dissolved organic matter (CDOM) by UV-B radiation decreases CDOM absorption in the UV region and fluorescence intensity, and alters CDOM composition. CDOM absorption, fluorescence, and the spectral slope indicating the CDOM composition were studied using

  8. Advances in UV-Plasmonics: A Detailed Analysis of Metallic Materials as Candidates for New Applications in Nanothecnology

    Science.gov (United States)

    2014-08-26

    Indium, Rhodium, Ruthenium, Tungsten, Titanium, Chromium, Palladium, Copper, Platinum and Magnesium . These have been chosen because all of them...performance. vii. Considering that the observed behaviors occur precisely where UV surface-enhanced Raman spectra indicated strong local field...research objective was centered on the UV plasmonic properties of Rh NPs by means of surface-enhanced Raman spectroscopy, surface-enhanced

  9. Photoreactivation rescue and dark repair demonstrated in UV-irradiated embryos of the self-fertilizing fish Rivulus ocellatus marmoratus (Teleostei; Aplocheilidae)

    International Nuclear Information System (INIS)

    Park, E.-H.; Yi, A.-K.

    1989-01-01

    The effects of photoreactivation (PR) rescue and dark repair on the survival of UV-irradiated embryos of the hermaphroditic fish (Rivulus ocellatus marmoratus) are reported. When UV-irradiated embryos were illuminated by photoreactivating light (PRL) from fluorescent lamps, survival at the hatching stage was markedly increased. The maximum recovery to UV damage was shown by embryos that were exposed to PRL for at least 6 h after UV irradiation. The effect of PRL decreased 30 min after UV irradiation and not PR rescue ws detected beyond 96 h. Treatment with 2 mM caffeine for 48 h after UV irradiation increased the sensitivity of the embryos in the dark. The above results demonstrate that Rivulus embryos have an efficient PR system and a caffeine-sensitive dark repair capacity. (author). 31 refs.; 5 figs

  10. Definition of Quality Criteria of the Technological Process of Narrow Web UV-Printing

    OpenAIRE

    Volodymyr Shybanov; Vsevolod Senkivsky; Vyacheslav Repeta; Natalia Gurgal

    2013-01-01

    The application of Narrow Web UV-flexographic printing has several advantages compared with offset printing. In particular, they are the lack of the operation of water-ink balance setting in the technological process, the ability to print on a wide range of materials and so on. Though the imprint quality is clearly based on standards in offset printing, there are no clearly indicated requirements for Narrow Web UV flexographic printing. The absence of such requirements on quality parameters o...

  11. Development of aluminum gallium nitride based optoelectronic devices operating in deep UV and terahertz spectrum ranges

    Science.gov (United States)

    Zhang, Wei

    In this research project I have investigated AlGaN alloys and their quantum structures for applications in deep UV and terahertz optoelectronic devices. For the deep UV emitter applications the materials and devices were grown by rf plasma-assisted molecular beam epitaxy on 4H-SiC, 6H-SiC and c-plane sapphire substrates. In the growth of AlGaN/AlN multiple quantum wells on SiC substrates, the AlGaN wells were grown under excess Ga, far beyond than what is required for the growth of stoichiometric AlGaN films, which resulted in liquid phase epitaxy growth mode. Due to the statistical variations of the excess Ga on the growth front we found that this growth mode leads to films with lateral variations in the composition and thus, band structure potential fluctuations. Transmission electron microscopy shows that the wells in such structures are not homogeneous but have the appearance of quantum dots. We find by temperature dependent photoluminescence measurements that the multiple quantum wells with band structure potential fluctuations emit at 240 nm and have room temperature internal quantum efficiency as high as 68%. Furthermore, they were found to have a maximum net modal optical gain of 118 cm-1 at a transparency threshold corresponding to 1.4 x 1017 cm-3 excited carriers. We attribute this low transparency threshold to population inversion of only the regions of the potential fluctuations rather than of the entire matrix. Some prototype deep UV emitting LED structures were also grown by the same method on sapphire substrates. Optoelectronic devices for terahertz light emission and detection, based on intersubband transitions in III-nitride semiconductor quantum wells, were grown on single crystal c-plane GaN substrates. Growth conditions such the ratio of group III to active nitrogen fluxes, which determines the appropriate Ga-coverage for atomically smooth growth without requiring growth interruptions were employed. Emitters designed in the quantum cascade

  12. Degradation study of different brands of paracetamol by UV spectroscopy

    Directory of Open Access Journals (Sweden)

    Safila Naveed

    2016-05-01

    Full Text Available Objective: To investgate the forced degradation study for the determination of degradation of the drug substance. Methods: Paracetamol was exposed to different conditions according to International Conference on Harmonization guideline. The amount of degradation product can be calculated with the help of UV spectrophotometer. The official test limits according to British Pharmacopoeia/United States Pharmacopoeia should not less than and should not more than lapelled amount. Forced degradation of drug substance was exposed to acidic and basic medium of panadol. Forced degradation of drug substance of panadol, disprol and calpol were also observed negligible difference in availability on exposure to UV and heat. This method can be used successfully for studying the stress degradation factors. Because this method is less time consuming and simple and cost effective also. Results: The brands i.e. calpol, panadol and disprol, when they come in contact with different degradation parameters (before, acid, base, heat and UV treatments according to statistical analysis, the result showed significant values (P < 0.05 which indicated that there was no degradation in any of the brand. Conclusions: The result indicated there is no degradation found in these brands.

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

    Science.gov (United States)

    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.

  14. UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings

    International Nuclear Information System (INIS)

    Drincovich, M.F.; Casati, P.; Andreo, C.S.; Donahue, R.; Edwards, G.E.

    1998-01-01

    The effect of treatment of etiolated maize seedlings with UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400–700 nm), on the activity and quantity of NADP-malic enzyme (NADPME) and on RNA levels was determined. Under low levels of PAR (14 µmol m –2 s –1 ), exposure to UV-B radiation (9 µmol m –2 s –1 ) but not UV-A radiation (11 µmol m –2 s –1 ) for 6–24 h caused a marked increase in the activity of the enzyme similar to that observed under high PAR (300 µmol m –2 s –1 ) in the absence of UV-B. Western blot analysis indicated there was a specific increase of the photosynthetically active isoform of the enzyme. This increase was also measured at the RNA level by dot blot analysis, indicating that the induction is displayed at the level of NADP-ME transcription. UV-B treatment of green leaves after a 12 h dark period also caused an increase in the activity and level of NADP-ME. The UV-B induction of NADP-ME synthesis may reflect a mechanism for induction of photosynthetic processes in C4 photosynthesis. Alternatively, the relatively low intensity of UV-B radiation present under full sunlight might provide a signal that facilitates repair of UV-B-induced damage through the increased activity of different enzymes such as NADP-ME. It is speculated that the reducing power and pyruvate generated by activity of NADP-ME may be used for respiration in cellular repair processes and as substrates for the fatty acid synthesis required for membrane repair. (author)

  15. UV time-dependent emission in SY Muscae

    International Nuclear Information System (INIS)

    Michalitsianos, A.G.; Kafatos, M.

    1982-01-01

    Ultraviolet spectra acquired with the International Ultraviolet Explorer (IUE) of SY Mus = HD 10036 on 20 September 1980 and 11 June 1981 indicate a substantial enhancement of UV emission over a nine month period. The general UV flux level appears to have increased by approximately one order of magnitude between the first and second observing epochs. The strong ultraviolet continuum evident throughout the entire IUE spectral range lambdalambda1200-3200 A on 11 June 1981 is closely approximated by a star with Tsub(eff) = 40,000 K, where previously on 20 September 1980 the continuum distribution presented a more complex structure that is possibly explained by a combination of thermal emission from an early type main sequence star, and nebular recombination emission (Michalitsianos et al. 1981). (Auth.)

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

    Science.gov (United States)

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

    2015-01-01

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

  17. Application of UV Imaging in Formulation Development

    DEFF Research Database (Denmark)

    Sun, Yu; Østergaard, Jesper

    2017-01-01

    defining formulation behavior after exposure to the aqueous environments and pharmaceutical performance is critical in pharmaceutical development, manufacturing and quality control of drugs. UV imaging has been explored as a tool for qualitative and quantitative characterization of drug dissolution...... related to the structural properties of the drug substance or formulation can be monitored. UV imaging is a non-intrusive and simple-to-operate analytical technique which holds potential for providing a mechanistic foundation for formulation development. This review aims to cover applications of UV...

  18. Global Solar UV Index (invited paper)

    International Nuclear Information System (INIS)

    Repacholi, M.H.

    2000-01-01

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

  19. RPC industries - UV and EB equipment manufacturers

    International Nuclear Information System (INIS)

    Rodrigues, A.M.

    1987-01-01

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

  20. Transformation of UV-hypersensitive Chinese hamster ovary cell mutants with UV-irradiated plasmids

    International Nuclear Information System (INIS)

    Nairn, R.S.; Humphrey, R.M.; Adair, G.M.

    1988-01-01

    Transfection of UV-hypersensitive, DNA repair-deficient Chinese hamster ovary (CHO) cell lines and parental, repair-proficient CHO cells with UV-irradiated pHaprt-1 or pSV2gpt plasmids resulted in different responses by recipient cell lines to UV damage in transfected DNA. Unlike results reported for human cells, UV irradiation of transfecting DNA did not stimulate genetic transformation of CHO recipient cells. In repair-deficient CHO cells, proportionally fewer transformants were produced with increasing UV damage than in repair-proficient cells in transfections with UV-irradiated hamster adenine phosphoribosyltransferase (APRT) gene contained in plasmid pHaprt-1. Transfection of CHO cells with UV-irradiated pSV2gpt resulted in neither decline in transformation frequencies in repair-deficient cell lines relative to repair-proficient cells nor stimulation of genetic transformation by UV damage in the plasmid. Blot hybridization analysis of DNA samples isolated from transformed cells showed no dramatic changes in copy number or arrangement of transfected plasmid DNA with increasing UV dose. The authors conclude responses of recipient cells to UV-damaged transfecting plasmids depend on type of recipient cell and characteristics of the genetic sequence used for transfection. (author)

  1. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi.

    Science.gov (United States)

    Lando, Gabriela Albara; Marconatto, Letícia; Kessler, Felipe; Lopes, William; Schrank, Augusto; Vainstein, Marilene Henning; Weibel, Daniel Eduardo

    2017-07-18

    Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU) are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae , when the films were pre-treated with Ultraviolet (UV) irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), scanning electron microscopy (SEM), and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  2. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Gabriela Albara Lando

    2017-07-01

    Full Text Available Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae, when the films were pre-treated with Ultraviolet (UV irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR, scanning electron microscopy (SEM, and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  3. 75 FR 43840 - Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum Civil Monetary Penalties for...

    Science.gov (United States)

    2010-07-27

    ...-17530; Notice No. 2] RIN 2130-ZA03 Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum... remains at $250. These adjustments are required by the Federal Civil Penalties Inflation Adjustment Act [email protected] . SUPPLEMENTARY INFORMATION: The Federal Civil Penalties Inflation Adjustment Act of 1990...

  4. Zipf's law, power laws and maximum entropy

    International Nuclear Information System (INIS)

    Visser, Matt

    2013-01-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified. (paper)

  5. Maximum-entropy description of animal movement.

    Science.gov (United States)

    Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M

    2015-03-01

    We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.

  6. Pareto versus lognormal: a maximum entropy test.

    Science.gov (United States)

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2011-08-01

    It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.

  7. Maximum likelihood estimation for integrated diffusion processes

    DEFF Research Database (Denmark)

    Baltazar-Larios, Fernando; Sørensen, Michael

    We propose a method for obtaining maximum likelihood estimates of parameters in diffusion models when the data is a discrete time sample of the integral of the process, while no direct observations of the process itself are available. The data are, moreover, assumed to be contaminated...... EM-algorithm to obtain maximum likelihood estimates of the parameters in the diffusion model. As part of the algorithm, we use a recent simple method for approximate simulation of diffusion bridges. In simulation studies for the Ornstein-Uhlenbeck process and the CIR process the proposed method works...... by measurement errors. Integrated volatility is an example of this type of observations. Another example is ice-core data on oxygen isotopes used to investigate paleo-temperatures. The data can be viewed as incomplete observations of a model with a tractable likelihood function. Therefore we propose a simulated...

  8. A Maximum Radius for Habitable Planets.

    Science.gov (United States)

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

  9. Maximum parsimony on subsets of taxa.

    Science.gov (United States)

    Fischer, Mareike; Thatte, Bhalchandra D

    2009-09-21

    In this paper we investigate mathematical questions concerning the reliability (reconstruction accuracy) of Fitch's maximum parsimony algorithm for reconstructing the ancestral state given a phylogenetic tree and a character. In particular, we consider the question whether the maximum parsimony method applied to a subset of taxa can reconstruct the ancestral state of the root more accurately than when applied to all taxa, and we give an example showing that this indeed is possible. A surprising feature of our example is that ignoring a taxon closer to the root improves the reliability of the method. On the other hand, in the case of the two-state symmetric substitution model, we answer affirmatively a conjecture of Li, Steel and Zhang which states that under a molecular clock the probability that the state at a single taxon is a correct guess of the ancestral state is a lower bound on the reconstruction accuracy of Fitch's method applied to all taxa.

  10. UV-sensitive optical sensors based on ITO-gallium phosphide heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Oleksandr; Hidalga-Wade, F. Javier de la; Zuniga-Islas, Carlos; Abundis Patino, Jesus H. [National Institute for Astrophysics, Optics, and Electronics (INAOE), Puebla (Mexico)

    2010-04-15

    Design and characteristics of wide-band UV sensors based on ITO/GaP heterostructures are discussed. Such sensors have perfect electrical parameters and high UV-visible sensitivity in comparison with surface-barrier structures using a semi-transparent thin metal film as an electrode. Many applications require UV sensors with an effective rejection of visible radiation and a wide temperature operating interval. For this aim, the theoretical modelling of extreme selective optical sensors with a double Ag/ITO thin film on the GaP surface, in which the thin silver film serves as a narrow bandpass filter at 320 nm, has been conducted. With this modelling the optimal thickness combination for the silver and ITO films was found for the maximum rejection of the sensitivity to visible radiation (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. High efficiency single frequency 355 nm all-solid-state UV laser

    International Nuclear Information System (INIS)

    Xie, Xiaobing; Wei, Daikang; Ma, Xiuhua; Li, Shiguang; Liu, Jiqiao; Zhu, Xiaolei; Chen, Weibiao

    2016-01-01

    A novel conductively cooled high energy single-frequency 355 nm all-solid-state UV laser is presented based on sum-frequency mixing technique. In this system, a pulsed seeder laser at 1064 nm wavelength, modulated by an AOM, is directly amplified by the cascaded multi-stage hybrid laser amplifiers, and two LBO crystals are used for the SHG and SFG, finally a maximum UV pulse energy of 226 mJ at 355 nm wavelength is achieved with frequency-tripled conversion efficiency as high as 55%, the pulse width is around 12.2 ns at the repetition frequency of 30 Hz. The beam quality factor M 2 of the output UV laser is measured to be 2.54 and 2.98 respectively in two orthogonal directions. (paper)

  12. Maximum entropy analysis of liquid diffraction data

    International Nuclear Information System (INIS)

    Root, J.H.; Egelstaff, P.A.; Nickel, B.G.

    1986-01-01

    A maximum entropy method for reducing truncation effects in the inverse Fourier transform of structure factor, S(q), to pair correlation function, g(r), is described. The advantages and limitations of the method are explored with the PY hard sphere structure factor as model input data. An example using real data on liquid chlorine, is then presented. It is seen that spurious structure is greatly reduced in comparison to traditional Fourier transform methods. (author)

  13. Increased exposure to UV-B radiation during early development leads to enhanced photoprotection and improved long-term performance in Lactuca sativa.

    Science.gov (United States)

    Wargent, Jason J; Elfadly, Eslam M; Moore, Jason P; Paul, Nigel D

    2011-08-01

    Plant responses to solar UV radiation are numerous and have often been considered from a perspective of negative outcomes for plant productivity. In this study, we used two experimental approaches consisting of: (1) field-based spectrally modifying filters in addition to (2) controlled indoor exposure to UV-B, to examine the effects of UV radiation on growth and photosynthetic performance of lettuce (Lactuca sativa L.) seedlings. Various aspects of growth were affected in plants grown under a UV-inclusive environment compared to a UV-depleted environment, including reductions in leaf expansion, increases in leaf thickness and the rate of net photosynthesis. After transplantation to a uniform field environment, lettuce plants initially propagated under the UV-inclusive environment exhibited higher harvestable yields than those from a UV-depleted environment. In controlled conditions, photosynthetic rates were higher in plants grown in the presence of UV-B radiation, and relative growth of plants pre-acclimatized to UV-B was also increased, in addition to higher maximum photochemical efficiency of photosystem II (PSII) (F(v) /F(m) ) following subsequent exposure to high photosynthetically active radiation (PAR) and temperature stress. Our findings are discussed within the context of sustainability in agriculture and the paradigm shift in photobiology which such beneficial responses to UV radiation could represent. © 2011 Blackwell Publishing Ltd.

  14. A Maximum Resonant Set of Polyomino Graphs

    Directory of Open Access Journals (Sweden)

    Zhang Heping

    2016-05-01

    Full Text Available A polyomino graph P is a connected finite subgraph of the infinite plane grid such that each finite face is surrounded by a regular square of side length one and each edge belongs to at least one square. A dimer covering of P corresponds to a perfect matching. Different dimer coverings can interact via an alternating cycle (or square with respect to them. A set of disjoint squares of P is a resonant set if P has a perfect matching M so that each one of those squares is M-alternating. In this paper, we show that if K is a maximum resonant set of P, then P − K has a unique perfect matching. We further prove that the maximum forcing number of a polyomino graph is equal to the cardinality of a maximum resonant set. This confirms a conjecture of Xu et al. [26]. We also show that if K is a maximal alternating set of P, then P − K has a unique perfect matching.

  15. Automatic maximum entropy spectral reconstruction in NMR

    International Nuclear Information System (INIS)

    Mobli, Mehdi; Maciejewski, Mark W.; Gryk, Michael R.; Hoch, Jeffrey C.

    2007-01-01

    Developments in superconducting magnets, cryogenic probes, isotope labeling strategies, and sophisticated pulse sequences together have enabled the application, in principle, of high-resolution NMR spectroscopy to biomolecular systems approaching 1 megadalton. In practice, however, conventional approaches to NMR that utilize the fast Fourier transform, which require data collected at uniform time intervals, result in prohibitively lengthy data collection times in order to achieve the full resolution afforded by high field magnets. A variety of approaches that involve nonuniform sampling have been proposed, each utilizing a non-Fourier method of spectrum analysis. A very general non-Fourier method that is capable of utilizing data collected using any of the proposed nonuniform sampling strategies is maximum entropy reconstruction. A limiting factor in the adoption of maximum entropy reconstruction in NMR has been the need to specify non-intuitive parameters. Here we describe a fully automated system for maximum entropy reconstruction that requires no user-specified parameters. A web-accessible script generator provides the user interface to the system

  16. maximum neutron flux at thermal nuclear reactors

    International Nuclear Information System (INIS)

    Strugar, P.

    1968-10-01

    Since actual research reactors are technically complicated and expensive facilities it is important to achieve savings by appropriate reactor lattice configurations. There is a number of papers, and practical examples of reactors with central reflector, dealing with spatial distribution of fuel elements which would result in higher neutron flux. Common disadvantage of all the solutions is that the choice of best solution is done starting from the anticipated spatial distributions of fuel elements. The weakness of these approaches is lack of defined optimization criteria. Direct approach is defined as follows: determine the spatial distribution of fuel concentration starting from the condition of maximum neutron flux by fulfilling the thermal constraints. Thus the problem of determining the maximum neutron flux is solving a variational problem which is beyond the possibilities of classical variational calculation. This variational problem has been successfully solved by applying the maximum principle of Pontrjagin. Optimum distribution of fuel concentration was obtained in explicit analytical form. Thus, spatial distribution of the neutron flux and critical dimensions of quite complex reactor system are calculated in a relatively simple way. In addition to the fact that the results are innovative this approach is interesting because of the optimization procedure itself [sr

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

    Science.gov (United States)

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

    2018-03-01

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

  18. Energy-donor phosphorescence quenching study of triplet–triplet energy transfer between UV absorbers

    International Nuclear Information System (INIS)

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

    2015-01-01

    The intermolecular triplet–triplet energy transfer from a photounstable UV-A absorber, 4-tert-butyl-4′-methoxydibenzoylmethane (BMDBM), to UV-B absorbers, 2-ethylhexyl 4-methoxycinnamate (octyl methoxycinnamate, OMC), octocrylene (OCR) and dioctyl 4-methoxybenzylidenemalonate (DOMBM) has been observed using a 355 nm laser excitation in rigid solutions at 77 K. The decay curves of the energy-donor phosphorescence in the presence of the UV-B absorbers deviate from the exponential decay at the initial stage of the decay. The Stern–Volmer formulation is not valid in rigid solutions because molecular diffusion is impossible. The experimental results indicate that the rate constant of triplet–triplet energy transfer from BMDBM to the UV-B absorbers, k T–T , decreases in the following order: k T–T (BMDBM–DOMBM)>k T–T (BMDBM–OMC)≥k T–T (BMDBM–OCR). The presence of DOMBM enhances the photostability of the widely used combination of UV-A and UV-B absorbers, BMDBM and OCR. The effects of the triplet–triplet energy transfer on the photostability of BMDBM are discussed. - Highlights: • The intermolecular triplet–triplet energy transfer between UV absorbers was observed. • The phosphorescence decay deviates from exponential at the initial stage of decay. • The effects of triplet–triplet energy transfer on the photostability are discussed

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

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

    International Nuclear Information System (INIS)

    Kochevar, I.E.

    1985-01-01

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

  1. Optimal Portfolio Strategy under Rolling Economic Maximum Drawdown Constraints

    Directory of Open Access Journals (Sweden)

    Xiaojian Yu

    2014-01-01

    Full Text Available This paper deals with the problem of optimal portfolio strategy under the constraints of rolling economic maximum drawdown. A more practical strategy is developed by using rolling Sharpe ratio in computing the allocation proportion in contrast to existing models. Besides, another novel strategy named “REDP strategy” is further proposed, which replaces the rolling economic drawdown of the portfolio with the rolling economic drawdown of the risky asset. The simulation tests prove that REDP strategy can ensure the portfolio to satisfy the drawdown constraint and outperforms other strategies significantly. An empirical comparison research on the performances of different strategies is carried out by using the 23-year monthly data of SPTR, DJUBS, and 3-month T-bill. The investment cases of single risky asset and two risky assets are both studied in this paper. Empirical results indicate that the REDP strategy successfully controls the maximum drawdown within the given limit and performs best in both return and risk.

  2. UV light induces premature senescence in Akt1-null mouse embryonic fibroblasts by increasing intracellular levels of ROS

    International Nuclear Information System (INIS)

    Jee, Hye Jin; Kim, Hyun-Ju; Kim, Ae Jeong; Bae, Yoe-Sik; Bae, Sun Sik; Yun, Jeanho

    2009-01-01

    Akt/PKB plays a pivotal role in cell survival and proliferation. Previously, we reported that UV-irradiation induces extensive cell death in Akt2 -/- mouse embryonic fibroblasts (MEFs) while Akt1 -/- MEFs show cell cycle arrest. Here, we find that Akt1 -/- MEFs exhibit phenotypic changes characteristics of senescence upon UV-irradiation. An enlarged and flattened morphology, a reduced cell proliferation and an increased senescence-associated β-galactosidase (SA β-gal) staining indicate that Akt1 -/- MEFs undergo premature senescence after UV-irradiation. Restoring Akt1 expression in Akt1 -/- MEFs suppressed SA β-gal activity, indicating that UV-induced senescence is due to the absence of Akt1 function. Notably, levels of ROS were rapidly increased upon UV-irradiation and the ROS scavenger NAC inhibits UV-induced senescence of Akt1 -/- MEFs, suggesting that UV light induces premature senescence in Akt1 -/- MEFs by modulating intracellular levels of ROS. In conjunction with our previous work, this indicates that different isoforms of Akt have distinct function in response to UV-irradiation.

  3. New technology and application in UV curing

    International Nuclear Information System (INIS)

    Loutz, J.M.

    1999-01-01

    Overview of radcure technology was presented. Its included this following subjects, radiation curable powder coatings, UV curable water based polyurethanes, photo-initiators, fire retardancy, aqueous systems, cationic, ceramic and optical grade material

  4. Effect of UV irradiation on cutaneous cicatrices

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  5. UV curable palm oil based ink

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Mohd Hilmi Mahmood; Khairul Zaman Mohd Dahlan; Rosley Che Ismail

    2002-01-01

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil urethane acrylate (POBUA) as a prepolymer in the UV ink system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  6. UV curable palm oil based inks

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Hilmi Mahmood

    2002-01-01

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil based urethane acrylate (POBUA) as a prepolymer in the UV inks system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  7. Accelerated Solar-UV Test Chamber

    Science.gov (United States)

    Gupta, A.; Laue, E. G.

    1984-01-01

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

  8. UV filters for lighting of plants

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

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

  9. Mean Annual UV-B Irradiance

    Data.gov (United States)

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

  10. UV Impacts Avoided by the Montreal Protocol

    Science.gov (United States)

    Newman, Paul; McKenzie, Richard

    2010-01-01

    Temporal and geographical variabilities in the future "World Expected" UV environment are compared with the "World Avoided", which would have occurred without the Montreal Protocol on protection of the ozone layer and its subsequent amendments and adjustments. Based on calculations of clear-sky UV irradiances, the effects of the Montreal Protocol have been hugely beneficial to avoid the health risks, such as skin cancer, which are associated with high UV, while there is only a small increase in health risks, such as vitamin D deficiency, that are associated with low UV. However, interactions with climate change may lead to changes in cloud and albedo, and possibly behavioural changes which could also be important.

  11. Progress in deep-UV photoresists

    Indian Academy of Sciences (India)

    Unknown

    This paper reviews the recent development and challenges of deep-UV photoresists and their ... small amount of acid, when exposed to light by photo- chemical ... anomalous insoluble skin and linewidth shift when the. PEB was delayed.

  12. Remote UV Fluorescence Lifetime Spectrometer, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop, demonstrate, and deliver to NASA an innovative, portable, and power efficient Remote UV Fluorescence Lifetime Spectrometer...

  13. Compact solar UV burst triggered in a magnetic field with a fan-spine topology

    Science.gov (United States)

    Chitta, L. P.; Peter, H.; Young, P. R.; Huang, Y.-M.

    2017-09-01

    Context. Solar ultraviolet (UV) bursts are small-scale features that exhibit intermittent brightenings that are thought to be due to magnetic reconnection. They are observed abundantly in the chromosphere and transition region, in particular in active regions. Aims: We investigate in detail a UV burst related to a magnetic feature that is advected by the moat flow from a sunspot towards a pore. The moving feature is parasitic in that its magnetic polarity is opposite to that of the spot and the pore. This comparably simple photospheric magnetic field distribution allows for an unambiguous interpretation of the magnetic geometry leading to the onset of the observed UV burst. Methods: We used UV spectroscopic and slit-jaw observations from the Interface Region Imaging Spectrograph (IRIS) to identify and study chromospheric and transition region spectral signatures of said UV burst. To investigate the magnetic topology surrounding the UV burst, we used a two-hour-long time sequence of simultaneous line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) and performed data-driven 3D magnetic field extrapolations by means of a magnetofrictional relaxation technique. We can connect UV burst signatures to the overlying extreme UV (EUV) coronal loops observed by the Atmospheric Imaging Assembly (AIA). Results: The UV burst shows a variety of extremely broad line profiles indicating plasma flows in excess of ±200 km s-1 at times. The whole structure is divided into two spatially distinct zones of predominantly up- and downflows. The magnetic field extrapolations show a persistent fan-spine magnetic topology at the UV burst. The associated 3D magnetic null point exists at a height of about 500 km above the photosphere and evolves co-spatially with the observed UV burst. The EUV emission at the footpoints of coronal loops is correlated with the evolution of the underlying UV burst. Conclusions: The magnetic field around the null point is sheared by

  14. UV sensitivity of various solid state detectors

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  15. Dynamic Optimization of UV Flash Processes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Jørgensen, John Bagterp

    2017-01-01

    UV ash processes, also referred to as isoenergetic-isochoric ash processes, occur for dynamic simulation and optimization of vapor-liquid equilibrium processes. Dynamic optimization and nonlinear model predictive control of distillation columns, certain two-phase ow problems, as well as oil reser...... that the optimization solver, the compiler, and high-performance linear algebra software are all important for e_cient dynamic optimization of UV ash processes....

  16. Bactericidal effectiveness of modulated UV light

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  17. UV spectra, bombs, and the solar atmosphere

    OpenAIRE

    Judge, Philip G.

    2015-01-01

    A recent analysis of UV data from the Interface Region Imaging Spectrograph {\\em IRIS} reports plasma "bombs" with temperatures near \\hot{} within the solar photosphere. This is a curious result, firstly because most bomb plasma pressures $p$ (the largest reported case exceeds $10^3$ dyn~cm$^{-2}$) fall well below photospheric pressures ($> 7\\times10^3$), and secondly, UV radiation cannot easily escape from the photosphere. In the present paper the {\\em IRIS} data is independently analyzed. I...

  18. Chronic effects of UV on human skin

    International Nuclear Information System (INIS)

    Cesarini, J.P.

    1996-01-01

    Chronic exposures and acute accidents of the skin to UV has been recognized as an important risk for skin cancers in human. Attempts have been made with mathematical models to correlate the ambient UV dose and occupational irradiations with the risk of skin cancers. Development of accurate global measurements of solar irradiance and personal dosimetry is expected in the future in order to reduce the exposure of the general population, to precise the measures to be taken for indoor and outdoor workers. (author)

  19. UV written compact broadband optical couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques.......In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques....

  20. UV written 1x8 optical splitters

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed.......In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed....

  1. Accurate modeling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  2. Accurate modelling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

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

    Science.gov (United States)

    Chen, Maosi

    from an improved cloud screening algorithm that utilizes an iterative rejection of cloudy points based on a decreasing tolerance of unstable optical depth behavior when calibration information is unknown. A MODTRAN radiative transfer model simulation showed the new cloud screening algorithm was capable of screening cloudy points while retaining clear-sky points. The comparison results showed that the cloud-free points determined by the new cloud screening algorithm generated significantly (56%) more and unbiased Langley offset voltages (VLOs) for both partly cloudy days and sunny days at two testing sites, Hawaii and Florida. The V¬LOs are proportional to the radiometric sensitivity. The stability of the calibration is also improved by the development of a two-stage reference channel calibration method for collocated UV-MFRSR and MFRSR instruments. Special channels where aerosol is the only contributor to total optical depth (TOD) variation (e.g. 368-nm channel) were selected and the radiative transfer model (MODTRAN) used to calculate direct normal and diffuse horizontal ratios which were used to evaluate the stability of TOD in cloud-free points. The spectral dependence of atmospheric constituents' optical properties and previously calibrated channels were used to find stable TOD points and perform Langley calibration at spectrally adjacent channels. The test of this method on the UV-B program site at Homestead, Florida (FL02) showed that the new method generated more clustered and abundant VLOs at all (UV-) MFRSR channels and potentially improved the accuracy by 2-4% at most channels and over 10% at 300-nm and 305-nm channels. In the second major part of this work, I calibrated the DayCent-UV model with ecosystem variables (e.g. soil water, live biomass), allowed maximum photodecay rate to vary with litter's initial lignin fraction in the model, and validated the optimized model with LIDET observation of remaining carbon and nitrogen at three semi-arid sites. I

  4. Matrix Optical Absorption in UV-MALDI MS.

    Science.gov (United States)

    Robinson, Kenneth N; Steven, Rory T; Bunch, Josephine

    2018-03-01

    In ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI MS) matrix compound optical absorption governs the uptake of laser energy, which in turn has a strong influence on experimental results. Despite this, quantitative absorption measurements are lacking for most matrix compounds. Furthermore, despite the use of UV-MALDI MS to detect a vast range of compounds, investigations into the effects of laser energy have been primarily restricted to single classes of analytes. We report the absolute solid state absorption spectra of the matrix compounds α-cyano-4-hydroxycinnamic acid (CHCA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), 2,5-dihydroxybenzoic acid (2,5-DHB), and 2,4,6-trihydroxyacetophenone (THAP). The desorption/ionization characteristics of these matrix compounds with respect to laser fluence was investigated using mixed systems of matrix with either angiotensin II, PC(34:1) lipid standard, or haloperidol, acting as representatives for typical classes of analyte encountered in UV-MALDI MS. The first absolute solid phase spectra for PNA, MBT, and THAP are reported; additionally, inconsistencies between previously published spectra for CHCA are resolved. In light of these findings, suggestions are made for experimental optimization with regards to matrix and laser wavelength selection. The relationship between matrix optical cross-section and wavelength-dependant threshold fluence, fluence of maximum ion yield, and R, a new descriptor for the change in ion intensity with fluence, are described. A matrix cross-section of 1.3 × 10 -17 cm -2 was identified as a potential minimum for desorption/ionization of analytes. Graphical Abstract ᅟ.

  5. Photodegradation and toxicity changes of antibiotics in UV and UV/H2O2 process

    International Nuclear Information System (INIS)

    Yuan Fang; Hu Chun; Hu Xuexiang; Wei Dongbin; Chen Yong; Qu Jiuhui

    2011-01-01

    The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H 2 O 2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H 2 O 2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R OH,UV , defined as the experimentally determined ·OH radical exposure per UV fluence. The R OH,UV values represent the background ·OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H 2 O 2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H 2 O 2 process was identified using GC-MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H 2 O 2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of ·OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H 2 O 2 process would be determined by parent compound degradation and toxicity changes.

  6. Impact of fouling on UV effectiveness

    International Nuclear Information System (INIS)

    Dykstra, T.S.; Chauret, C.

    2002-01-01

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

  7. Quantification of naphazoline nitrate by UV-spectrophoto-metry

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-12-01

    Full Text Available One of the main tasks of pharmaceutical chemistry – medical drugs study. Spectrophotometry is widely used in studying of the structure and composition (complexes, dyes, analytical reagents, etc. of various compounds. It widely used for qualitative and quantitative determination of substances (determination of elements traces in metals, alloys, technical facilities. The dependence between substance structure and its electronic spectrum is being studied by many researchers till nowadays. The aim of this work was to highlight the issues of naphazoline quantify definition techniques by the UV-spectrophotometry. According to the existing methods of quality control (MQC, naphazoline nitrate is a substance quantitatively determined by acid-base titration among a mixture of anhydrous acetic acid and acetic anhydride. Titration is carried out with a solution of 0,1 M perchloric acid (indicator - crystal violet. To check the quality of nasal drops nafazoline nitrate MQC is recommended UV-spectrophotometry: drug is dissolved in boric acid solution (20 g/l as the reference solution used solution pharmacopoeia standard sample substance nafazoline nitrate. The character of UV-spectra of the nafazoline nitrate in solvents of different polarity (water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl, 5M H2SO4, was defined and studied. Standard sample of nafazoline nitrate was obtained from the State Enterprise "Scientific and Expert Pharmacopoeia Centre Ukraine". In order to study UV-spectra nafazoline nitrate spectrophotometer SPECORD 200-222U214 (Germany was used. UV-spectrum of nafazoline nitrate in water and 95% ethanol are characterized by two maxima at 270 and 280 nm. Absorption band of nafazoline nitrate in 0, 1 M sodium hydroxide has two maxima at 271 and 280 nm, and in 0, 1 M solution of hydrochloric acid and 5 M solution of sulfuric acid maxima coincide with the maxima spectrum of the drug in water, 95% ethanol. In order to avoid errors associated with

  8. Removal of sulfamethoxazole, ibuprofen and nitrobenzene by UV and UV/chlorine processes: A comparative evaluation of 275 nm LED-UV and 254 nm LP-UV.

    Science.gov (United States)

    Kwon, Minhwan; Yoon, Yeojoon; Kim, Seonbaek; Jung, Youmi; Hwang, Tae-Mun; Kang, Joon-Wun

    2018-05-15

    The aim of this study is to evaluate the micropollutant removal capacity of a 275 nm light-emitting diode (LED)-UV/chlorine system. The sulfamethoxazole, ibuprofen, and nitrobenzene removal efficiencies of this system were compared with those of a conventional 254 nm low-pressure (LP)-UV system as a function of the UV dose. In a direct photolysis system, the photon reactivity of sulfamethoxazole is higher than that of nitrobenzene and ibuprofen at both wavelengths. The molar absorption coefficients and quantum yields of each micropollutant were as follows: sulfamethoxazole (ε SMX, 275 nm protonated  = 17,527 M -1  cm -1 , Φ SMX, 275 nm protonated  = 0.239, ε SMX, 275 nm deprotonated  = 8430 M -1  cm -1 , and Φ SMX, 275 nm deprotonated  = 0.026), nitrobenzene (ε NB, 275 nm  = 7176 M -1  cm -1 and Φ NB, 275 nm  = 0.057), and ibuprofen (ε NB, 275 nm  = 200 M -1  cm -1 and Φ IBF, 275 nm  = 0.067). The photon reactivity of chlorine species, i.e., HOCl and OCl-, were determined at 275 nm (ε HOCl, 275 nm  = 28 M -1  cm -1 , Φ HOCl, 275 nm  = 1.97, ε OCl-, 275 nm  = 245 M -1  cm -1 , and Φ OCl-, 275 nm  = 0.8), which indicate that the decomposition rate of OCl - is higher and that of HOCl is lower by 275 nm photolysis than that by 254 nm photolysis (ε HOCl, 254 nm  = 60 M -1  cm -1 , Φ HOCl, 254 nm  = 1.46, ε OCl-, 254 nm  = 58 M -1  cm -1 , and Φ OCl-, 254 nm  = 1.11). In the UV/chlorine system, the removal rates of ibuprofen and nitrobenzene were increased by the formation of OH and reactive chlorine species. The 275-nm LED-UV/chlorine system has higher radical yields at pH 7 and 8 than the 254 nm LP-UV/chlorine system. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Decolorization of Methylene Blue with TiO2 Sol via UV Irradiation Photocatalytic Degradation

    Directory of Open Access Journals (Sweden)

    Jun Yao

    2010-01-01

    Full Text Available TiO2 sol was prepared for the degradation of methylene blue (MB solution under ultraviolet (UV irradiation. The absorption spectra of MB indicated that the maximum wavelength, 663 nm, almost kept the same. The performance of 92.3% for color removal was reached after 160 min. The particle size of TiO2 sol was about 22.5 nm. X-ray diffraction showed that TiO2 consisted of a single anatase phase. The small size and anatase phase probably resulted in high photocatalytic activity of TiO2 sol. The degradation ratio decreased as the initial concentration of MB increased. The photodegradation efficiency decreased in the order of pH 2>pH 9>pH 7. Regarding catalyst load, the degradation increased with the mass of catalyst up to an amount of 1.5 g⋅L−1 then decreased as the mass continued to increase. The addition of H2O2 to TiO2 sol resulted in an increase on the degradation ratio.

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

    Science.gov (United States)

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

    2012-10-01

    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.

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

    Science.gov (United States)

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

    2009-02-01

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

  12. Effects of UV radiation on phytoplankton

    Science.gov (United States)

    Smith, Raymond C.; Cullen, John J.

    1995-07-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

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

    2018-01-01

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

  15. Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1−xN Buffer Layer

    Directory of Open Access Journals (Sweden)

    Chang-Ju Lee

    2017-07-01

    Full Text Available The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded AlxGa−xN buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded AlxGa1−xN buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10−2 A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

  16. High speed micromachining with high power UV laser

    Science.gov (United States)

    Patel, Rajesh S.; Bovatsek, James M.

    2013-03-01

    Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

  17. On the interaction of UV-B radiation (280-315 mm) with water stress in crop plants

    International Nuclear Information System (INIS)

    Balakumar, T.; Vincent, V.H.B.; Paliwal, K.

    1993-01-01

    Cowpea (Vigna unguiculata L. Walp.) seedlings (3-day-old) were subjected to 4 kinds of experimental treatments: (1) control without exposure to any stress (-D-UV), (2) moderate water stress with no UV-B irradiation (+D-UV), (3) no water stress but exposure to UV-B radiation (-D+UV), and (4) moderate water stress and exposure to UV-B (+D+UV). UV-B and drought stress in the combined form elicited beneficial effects on the morphological and growth characteristics, and a few additive inhibitory effects in some functional processes. An increase in the specific leaf weight (SLW) was observed in the combination of stresses, which could be a defence mechanism against UV-B. The combination of stresses promoted the synthesis of anthocyanins and phenolic compounds. The responses of plants to the combination of stresses indicate that during simultaneous exposure of plants to multiple stresses, one form of stress could minimize the damage by the other. The enhancement of superoxide dismutase (SOD) and catalase activities appear to serve as acclimation mechanisms to scavenge the toxic, free radicals of oxygen produced under stress conditions. However, the inhibition in nitrate metabolism was greater in the combined stresses than in either of the stresses imposed separately. The results of this study illustrate that the interaction of stresses during simultaneous multiple stress conditions brings out certain beneficial effects. (author)

  18. Isolation of UV-sensitive mutants of mouse L5178Y cells by a cell suspension spotting method

    International Nuclear Information System (INIS)

    Shiomi, T.; Hieda-Shiomi, N.; Sato, K.

    1982-01-01

    We have isolated 56 UV-sensitive mutant clones from a mouse L51 T/t line of L5178Y cells by a cell suspension spotting method. Five mutants have also been isolated from L51 T/t and L5178Y cells by the method reported by Thompson and coworkers. We divided the mutants into two groups, highly sensitive and moderately sensitive mutants, according to their sensitivity to UV irradiation. Fifty-eight mutants were highly sensitive and three were moderately sensitive to UV. The reconstruction experiments indicate that more than 90% of highly sensitive mutants were recovered by the cell suspension spotting method. Frequencies of recovered mutants highly sensitive to UV increased with increasing dose of mutagens. Recovered mutant frequency reached 10(-2) after treatment with 1.5 micrograms/ml of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) (survival 0.2%). Eight UV-sensitive mutants were divided into four complementation groups. These mutants were 2-6 times more sensitive to UV than parental L51 T/t cells in terms of D37 (dose required to reduce survival to 37%). Four representative UV-sensitive mutants which are classified into different complementation groups were examined for their sensitivity to killing by UV, 4-nitroquinoline-1-oxide (4NQO), mitomycin C (MMC), X-rays, and MNNG. All four classes of mutants were found to be cross-sensitive to UV, 4NQO, and MMC, but not sensitive to X-rays and MNNG

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

    Science.gov (United States)

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

    2018-06-01

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

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

    Science.gov (United States)

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

    2018-06-01

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

  1. Detection and repair of a UV-induced photosensitive lesion in the DNA of human cells

    International Nuclear Information System (INIS)

    Francis, A.A.; Regan, J.D.

    1986-01-01

    Irradiation with UV light results in damage to the DNA of human cells. The most numerous lesions are pyrimidine dimers; however, other lesions are known to occur and may contribute to the overall deleterious effect of UV irradiation. The authors have observed evidence of a UV-induced lesion other than pyrimidine dimers in the DNA of human cells by measuring DNA strand breaks induced by irradiating with 313-nm light following UV (254-nm) irradiation. The data suggest that, in normal cells, the lesion responsible for this effect is rapidly repaired or altered; whereas, in xeroderma pigmentosum variant cells it seems to remain unchanged. Some change apparently occurs in the DNA of xeroderma pigmentosum group A cells which results in an increase in photolability. These data indicate a deficiency in DNA repair of xeroderma pigmentosum variant cells as well as in xeroderma pigmentosum group A cells. (Auth.)

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

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  3. Maximum entropy decomposition of quadrupole mass spectra

    International Nuclear Information System (INIS)

    Toussaint, U. von; Dose, V.; Golan, A.

    2004-01-01

    We present an information-theoretic method called generalized maximum entropy (GME) for decomposing mass spectra of gas mixtures from noisy measurements. In this GME approach to the noisy, underdetermined inverse problem, the joint entropies of concentration, cracking, and noise probabilities are maximized subject to the measured data. This provides a robust estimation for the unknown cracking patterns and the concentrations of the contributing molecules. The method is applied to mass spectroscopic data of hydrocarbons, and the estimates are compared with those received from a Bayesian approach. We show that the GME method is efficient and is computationally fast

  4. Maximum power operation of interacting molecular motors

    DEFF Research Database (Denmark)

    Golubeva, Natalia; Imparato, Alberto

    2013-01-01

    , as compared to the non-interacting system, in a wide range of biologically compatible scenarios. We furthermore consider the case where the motor-motor interaction directly affects the internal chemical cycle and investigate the effect on the system dynamics and thermodynamics.......We study the mechanical and thermodynamic properties of different traffic models for kinesin which are relevant in biological and experimental contexts. We find that motor-motor interactions play a fundamental role by enhancing the thermodynamic efficiency at maximum power of the motors...

  5. Maximum entropy method in momentum density reconstruction

    International Nuclear Information System (INIS)

    Dobrzynski, L.; Holas, A.

    1997-01-01

    The Maximum Entropy Method (MEM) is applied to the reconstruction of the 3-dimensional electron momentum density distributions observed through the set of Compton profiles measured along various crystallographic directions. It is shown that the reconstruction of electron momentum density may be reliably carried out with the aid of simple iterative algorithm suggested originally by Collins. A number of distributions has been simulated in order to check the performance of MEM. It is shown that MEM can be recommended as a model-free approach. (author). 13 refs, 1 fig

  6. Multi-Channel Maximum Likelihood Pitch Estimation

    DEFF Research Database (Denmark)

    Christensen, Mads Græsbøll

    2012-01-01

    In this paper, a method for multi-channel pitch estimation is proposed. The method is a maximum likelihood estimator and is based on a parametric model where the signals in the various channels share the same fundamental frequency but can have different amplitudes, phases, and noise characteristics....... This essentially means that the model allows for different conditions in the various channels, like different signal-to-noise ratios, microphone characteristics and reverberation. Moreover, the method does not assume that a certain array structure is used but rather relies on a more general model and is hence...

  7. Conductivity maximum in a charged colloidal suspension

    Energy Technology Data Exchange (ETDEWEB)

    Bastea, S

    2009-01-27

    Molecular dynamics simulations of a charged colloidal suspension in the salt-free regime show that the system exhibits an electrical conductivity maximum as a function of colloid charge. We attribute this behavior to two main competing effects: colloid effective charge saturation due to counterion 'condensation' and diffusion slowdown due to the relaxation effect. In agreement with previous observations, we also find that the effective transported charge is larger than the one determined by the Stern layer and suggest that it corresponds to the boundary fluid layer at the surface of the colloidal particles.

  8. Dynamical maximum entropy approach to flocking.

    Science.gov (United States)

    Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco; Mora, Thierry; Piovani, Duccio; Tavarone, Raffaele; Walczak, Aleksandra M

    2014-04-01

    We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.

  9. Maximum Temperature Detection System for Integrated Circuits

    Science.gov (United States)

    Frankiewicz, Maciej; Kos, Andrzej

    2015-03-01

    The paper describes structure and measurement results of the system detecting present maximum temperature on the surface of an integrated circuit. The system consists of the set of proportional to absolute temperature sensors, temperature processing path and a digital part designed in VHDL. Analogue parts of the circuit where designed with full-custom technique. The system is a part of temperature-controlled oscillator circuit - a power management system based on dynamic frequency scaling method. The oscillator cooperates with microprocessor dedicated for thermal experiments. The whole system is implemented in UMC CMOS 0.18 μm (1.8 V) technology.

  10. Maximum entropy PDF projection: A review

    Science.gov (United States)

    Baggenstoss, Paul M.

    2017-06-01

    We review maximum entropy (MaxEnt) PDF projection, a method with wide potential applications in statistical inference. The method constructs a sampling distribution for a high-dimensional vector x based on knowing the sampling distribution p(z) of a lower-dimensional feature z = T (x). Under mild conditions, the distribution p(x) having highest possible entropy among all distributions consistent with p(z) may be readily found. Furthermore, the MaxEnt p(x) may be sampled, making the approach useful in Monte Carlo methods. We review the theorem and present a case study in model order selection and classification for handwritten character recognition.

  11. Multiperiod Maximum Loss is time unit invariant.

    Science.gov (United States)

    Kovacevic, Raimund M; Breuer, Thomas

    2016-01-01

    Time unit invariance is introduced as an additional requirement for multiperiod risk measures: for a constant portfolio under an i.i.d. risk factor process, the multiperiod risk should equal the one period risk of the aggregated loss, for an appropriate choice of parameters and independent of the portfolio and its distribution. Multiperiod Maximum Loss over a sequence of Kullback-Leibler balls is time unit invariant. This is also the case for the entropic risk measure. On the other hand, multiperiod Value at Risk and multiperiod Expected Shortfall are not time unit invariant.

  12. Improved Maximum Parsimony Models for Phylogenetic Networks.

    Science.gov (United States)

    Van Iersel, Leo; Jones, Mark; Scornavacca, Celine

    2018-05-01

    Phylogenetic networks are well suited to represent evolutionary histories comprising reticulate evolution. Several methods aiming at reconstructing explicit phylogenetic networks have been developed in the last two decades. In this article, we propose a new definition of maximum parsimony for phylogenetic networks that permits to model biological scenarios that cannot be modeled by the definitions currently present in the literature (namely, the "hardwired" and "softwired" parsimony). Building on this new definition, we provide several algorithmic results that lay the foundations for new parsimony-based methods for phylogenetic network reconstruction.

  13. Ancestral sequence reconstruction with Maximum Parsimony

    OpenAIRE

    Herbst, Lina; Fischer, Mareike

    2017-01-01

    One of the main aims in phylogenetics is the estimation of ancestral sequences based on present-day data like, for instance, DNA alignments. One way to estimate the data of the last common ancestor of a given set of species is to first reconstruct a phylogenetic tree with some tree inference method and then to use some method of ancestral state inference based on that tree. One of the best-known methods both for tree inference as well as for ancestral sequence inference is Maximum Parsimony (...

  14. Response of oxidative stress defense systems in rice (Oryza sativa) leaves with supplemental UV-B radiation

    International Nuclear Information System (INIS)

    Dai, Q.; Yan, B.; Huang, S.; Liu, X.; Peng, S.; Miranda, M.L.L.; Chavez, A.Q.; Vergara, B.S.; Olszyk, D.M.

    1997-01-01

    The impact of elevated ultraviolet-B radiation (UV-B, 280–320 nm) on membrane systems and lipid peroxidation, and possible involvement of active oxygen radicals was investigated in leaves of two UV-B susceptible rice cultivars (Oryza sativa L. cvs IR74 and Dular). Rice seedlings were grown in a greenhouse for 10 days and then treated with biologically effective UV-B (UV-B BE ) radiation for 28 days. Oxidative stress effects were evaluated by measuring superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentration and relative electrolyte conductivity (EC) for IR74 and Dular at 0 (control), 6 or 13 kJ m −2 day −1 UV-B BE . Significant increases in these parameters were found in rice plants grown at 13 vs 0 kJ m −2 day −1 UV-B BE after 28 days; indicating that disruption of membrane systems may be an eventual reason for UV-B-induced injury in rice plants. There was a positive correlation between O 2 − generation and increases in EC or MDA in leaves. Activities of enzymatic and nonenzymatic free radical scavengers were measured for IR74 after 7, 14, 21 and 28 days of exposure to 13 or 0 UV-B BE to evaluate dynamics of these responses over time. Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV-B BE after 14 days of UV-B exposure. Further exposure to 28 days of UV-B was associated with a decline in enzyme activities and ascorbic acid, but not glutathione. It is suggested that UV-B-induced injury may be associated with disturbance of active oxygen metabolism through the destruction and alteration of both enzymatic and nonenzymatic defense systems in rice. (author)

  15. UV-IR mixing in nonassociative Snyder ϕ4 theory

    Science.gov (United States)

    Meljanac, Stjepan; Mignemi, Salvatore; Trampetic, Josip; You, Jiangyang

    2018-03-01

    Using a quantization of the nonassociative and noncommutative Snyder ϕ4 scalar field theory in a Hermitian realization, we present in this article analytical formulas for the momentum-conserving part of the one-loop two-point function of this theory in D -, 4-, and 3-dimensional Euclidean spaces, which are exact with respect to the noncommutative deformation parameter β . We prove that these integrals are regularized by the Snyder deformation. These results indicate that the Snyder deformation does partially regularize the UV divergences of the undeformed theory, as it was proposed decades ago. Furthermore, it is observed that different nonassociative ϕ4 products can generate different momentum-conserving integrals. Finally, most importantly, a logarithmic infrared divergence emerges in one of these interaction terms. We then analyze sample momentum nonconserving integral qualitatively and show that it could exhibit IR divergence too. Therefore, infrared divergences should exist, in general, in the Snyder ϕ4 theory. We consider infrared divergences at the limit p →0 as UV/IR mixings induced by nonassociativity, since they are associated to the matching UV divergence in the zero-momentum limit and appear in specific types of nonassociative ϕ4 products. We also discuss the extrapolation of the Snyder deformation parameter β to negative values as well as certain general properties of one-loop quantum corrections in Snyder ϕ4 theory at the zero-momentum limit.

  16. On the UV Dimensions of Loop Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Michele Ronco

    2016-01-01

    Full Text Available Planck-scale dynamical dimensional reduction is attracting more and more interest in the quantum-gravity literature since it seems to be a model independent effect. However, different studies base their results on different concepts of space-time dimensionality. Most of them rely on the spectral dimension; others refer to the Hausdorff dimension; and, very recently, the thermal dimension has also been introduced. We here show that all these distinct definitions of dimension give the same outcome in the case of the effective regime of Loop Quantum Gravity (LQG. This is achieved by deriving a modified dispersion relation from the hypersurface-deformation algebra with quantum corrections. Moreover, we also observe that the number of UV dimensions can be used to constrain the ambiguities in the choice of these LQG-based modifications of the Dirac space-time algebra. In this regard, introducing the polymerization of connections, that is, K→sin⁡δK/δ, we find that the leading quantum correction gives dUV=2.5. This result may indicate that the running to the expected value of two dimensions is ongoing, but it has not been completed yet. Finding dUV at ultrashort distances would require going beyond the effective approach we here present.

  17. Membrane lipid peroxidation by UV-A: Mechanism and implications

    International Nuclear Information System (INIS)

    Bose, B.; Agarwal, S.; Chatterjee, S.N.

    1990-01-01

    UV-A produced a dose-dependent linear increase of lipid peroxidation in liposomal membrane, as detected by the assay of (i) conjugated dienes, (ii) lipid hydroperoxides, (iii) malondialdehydes (MDA), and (iv) the fluorescent adducts formed by the reaction of MDA with glycine and also a linear dose-dependent increase of [ 14 C]glucose efflux from the liposomes. UV-A-induced MDA production could not be inhibited by any significant degree by sodium formate, dimethyl sulfoxide, EDTA, or superoxide dismutase but was very significantly inhibited by butylated hydroxytoluene, alpha-tocopherol, sodium azide, L-histidine, dimethylfuran, and beta-carotene. MDA formation increased with an increase in the D 2 O content in water, leading to a maximal amount of nearly 50% enhancement of lipid peroxidation in 100% D 2 O vis-a-vis water used as dispersion medium. The experimental findings indicate the involvement of singlet oxygen as the initiator of the UV-A-induced lipid peroxidation

  18. Deficiency of UV-induced excision repair in human thymocytes

    International Nuclear Information System (INIS)

    Gensler, H.L.; Lindberg, R.E.; Pinnas, J.L.; Jones, J.F.

    1985-01-01

    The capacity of human thymocytes and of differentiated lymphocytes circulating in peripheral blood to perform unscheduled DNA synthesis (a measure of nucleotide excision repair) after UV irradiation was measured by radioautographic analysis. Only 4% of immature T lymphocytes, but 68% of circulating lymphocytes exhibited unscheduled DNA synthesis. When UV sensitivity of peripheral blood lymphocytes and thymocytes from the same donor were compared, the thymocytes, in each case, were significantly more UV sensitive than were the circulating lymphocytes. Peripheral blood lymphocytes from subjects undergoing halothane and morphine anesthesia during surgery showed 56% less excision repair capacity than those from unanesthetized donors. The difference occurred in the number of cells capable of repair rather than in the extent of repair synthesis per cell. Ultraviolet-induced unscheduled DNA synthesis occurred in only 3% of the thymocytes removed from rats killed by cervical dislocation. Therefore, the deficiency of excision repair was observed in rat thymocytes which had not been affected by anesthesia or surgical trauma. The results indicate that immature T-cells are deficient in nucleotide excision repair whereas the majority of mature peripheral blood lymphocytes exhibit such repair. (author)

  19. Proteolytic activities in yeast after UV irradiation. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Schwencke, J.; Moustacchi, E.

    1982-04-01

    When the levels of three common yeast proteinases in exponentially growing cells of mutants blocked in different repair pathways are compared to that of isogenic wild-type cells, it can be seen that the level of proteinase B is enhanced in the mutants whereas the levels of leucin aminopeptidase (Leu.AP) and lysine aminopeptidase (Lys.AP) are similar in all strains. As in its corresponding wild type, the level of proteinase B activity is further enhanced after UV-irradiation in a mutant blocked in excision-repair (rad1-3). In contrast, following the same treatment the level of proteinase B remains almost constant in a mutant blocked in a general error-prone repair system (rad6-1) and in a mutant defective in a more specific mutagenic repair pathway (pso2-1). Cycloheximide, an inhibitor of protein synthesis, blocks the post-UV enhancement in proteinase B activity observed in rad1-3 indicating that, as in the wild-type cells, an inducible process is involved. The levels of Lys.AP and Leu.AP are, respectively, either unaffected or only moderately increased following UV-treatment of the repair defective mutants, as in wild-type strains.

  20. Statistics of the first passage time of Brownian motion conditioned by maximum value or area

    International Nuclear Information System (INIS)

    Kearney, Michael J; Majumdar, Satya N

    2014-01-01

    We derive the moments of the first passage time for Brownian motion conditioned by either the maximum value or the area swept out by the motion. These quantities are the natural counterparts to the moments of the maximum value and area of Brownian excursions of fixed duration, which we also derive for completeness within the same mathematical framework. Various applications are indicated. (paper)