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Sample records for promieniowanie uv-c lub

  1. Negative thermal expansion and anomalies of heat capacity of LuB50 at low temperatures.

    PubMed

    Novikov, V V; Zhemoedov, N A; Matovnikov, A V; Mitroshenkov, N V; Kuznetsov, S V; Bud'ko, S L

    2015-09-28

    Heat capacity and thermal expansion of LuB50 boride were experimentally studied in the 2-300 K temperature range. The data reveal an anomalous contribution to the heat capacity at low temperatures. The value of this contribution is proportional to the first degree of temperature. It was identified that this anomaly in heat capacity is caused by the effect of disorder in the LuB50 crystalline structure and it can be described in the soft atomic potential model (SAP). The parameters of the approximation were determined. The temperature dependence of LuB50 heat capacity in the whole temperature range was approximated by the sum of SAP contribution, Debye and two Einstein components. The parameters of SAP contribution for LuB50 were compared to the corresponding values for LuB66, which was studied earlier. Negative thermal expansion at low temperatures was experimentally observed for LuB50. The analysis of the experimental temperature dependence for the Gruneisen parameter of LuB50 suggested that the low-frequency oscillations, described in SAP mode, are responsible for the negative thermal expansion. Thus, the glasslike character of the behavior of LuB50 thermal characteristics at low temperatures was confirmed.

  2. Negative thermal expansion and anomalies of heat capacity of LuB50 at low temperatures

    DOE PAGES

    Novikov, V. V.; Zhemoedov, N. A.; Matovnikov, A. V.; ...

    2015-07-20

    Heat capacity and thermal expansion of LuB50 boride were experimentally studied in the 2–300 K temperature range. The data reveal an anomalous contribution to the heat capacity at low temperatures. The value of this contribution is proportional to the first degree of temperature. It was identified that this anomaly in heat capacity is caused by the effect of disorder in the LuB50 crystalline structure and it can be described in the soft atomic potential model (SAP). The parameters of the approximation were determined. The temperature dependence of LuB50 heat capacity in the whole temperature range was approximated by the summore » of SAP contribution, Debye and two Einstein components. The parameters of SAP contribution for LuB50 were compared to the corresponding values for LuB66, which was studied earlier. Negative thermal expansion at low temperatures was experimentally observed for LuB50. The analysis of the experimental temperature dependence for the Gruneisen parameter of LuB50 suggested that the low-frequency oscillations, described in SAP mode, are responsible for the negative thermal expansion. As a result, the glasslike character of the behavior of LuB50 thermal characteristics at low temperatures was confirmed.« less

  3. Heat capacity and thermal expansion of icosahedral lutetium boride LuB66

    SciTech Connect

    Novikov, V V; Avdashchenko, D V; Matovnikov, A V; Mitroshenkov, N V; Bud’ko, S L

    2014-01-07

    The experimental values of heat capacity and thermal expansion for lutetium boride LuB66 in the temperature range of 2-300 K were analysed in the Debye-Einstein approximation. It was found that the vibration of the boron sub-lattice can be considered within the Debye model with high characteristic temperatures; low-frequency vibration of weakly connected metal atoms is described by the Einstein model.

  4. Radiochromic film dosimetry for UV-C treatments of apple fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radiochromic films were evaluated for their suitability to estimate UV-C doses and dose uniformity on apple fruit surface. Parameters investigated included film type, color changes of the films in response to different UV-C doses, color stability of films, UV-C light intensity, and temperature. In...

  5. Inactivation of Listeria monocytogenes on Frozen Red Raspberries by Using UV-C Light.

    PubMed

    Liao, Yen-Te; Syamaladevi, Roopesh M; Zhang, Hongchao; Killinger, Karen; Sablani, Shyam

    2017-04-01

    In this study, the efficacy of UV-C treatment was determined on the reduction of foodborne pathogens on artificially contaminated frozen food surfaces. At first, the UV-C inactivation rates on 100 μl of the respective cocktails of Escherichia coli O157:H7, Salmonella , and Listeria monocytogenes covered underneath 0.5-cm-thick ice were examined. Simultaneously, the energy percentage of UV-C transmitted through the ice was determined. The experiments showed that more than 65% of the UV-C light energy passed through the ice and that UV-C susceptibility was in the descending order of E. coli O157:H7, Salmonella , and L. monocytogenes . L. monocytogenes , the most UV-C-resistant strain, was then selected to test on frozen raspberries. The UV-C inactivation kinetic data of L. monocytogenes were well described using the Weibull equation. During 720 s of UV-C exposure, with a total dose of 7.8 × 10(2) mJ/cm(2), a 1.5-log CFU/g reduction of L. monocytogenes population on the surface of frozen red raspberries was noted. No significant differences in total anthocyanins, total phenolics, and total antioxidant activity were observed between UV-C-treated and untreated frozen berries immediately after treatment. At the end of 9 months of storage at -35°C, UV-C-treated berries had statistically lower total phenolics, higher total anthocyanins, and similar total antioxidant activity compared with untreated berries. This study shows that UV-C light can be used to reduce the L. monocytogenes population on frozen raspberries.

  6. Proteomic Analyses of Changes in Synechococcus sp. PCC7942 Following UV-C Stress.

    PubMed

    Peng, Xi; Yang, Jie; Gao, Yang

    2017-01-25

    UV-C's effects on the physiological and biochemical processes of cyanobacteria have been well characterized. However, the molecular mechanisms of cyanobacteria's tolerance to UV-C still needs further investigation. This research attempts to decode the variation in protein abundances in cyanobacteria after UV-C stress. Different expression levels of proteins in the cytoplasm of Synechococcus sp. PCC7942 under UV-C stress were investigated by using a comparative proteomic approach. Forty-seven UV-C-regulated proteins were identified by MALDI-TOF analysis and classified by Gene Ontology (GO). After studying their pathways, the proteins were mainly enriched in the groups of protein folding, inorganic ion transport, and energy production. By focusing on these areas, this study reveals the correlation between UV-C stress-responsive proteins and the physiological changes of Synechococcus sp. PCC7942 under UV-C radiation. These findings may open up new areas for further exploration in the homeostatic mechanisms associated with cyanobacteria responses to UV-C radiation. This article is protected by copyright. All rights reserved.

  7. UV-C Radiation as a Factor Reducing Microbiological Contamination of Fish Meal

    PubMed Central

    Dobrzański, Zbigniew; Skowron, Karolina Jadwiga

    2014-01-01

    Fish meals, added to feeds as a source of protein, may contain pathogenic bacteria. Therefore, effective methods for their sanitizing, such as UV-C radiation, are needed to minimize the epidemiological risk. The objective of this study was to evaluate the effect of UV-C radiation on the sanitary state of fish meals. The research materials included salmon and cod meals. Samples of the fish meals were inoculated with suspensions of Salmonella, E. coli, enterococci, and C. sporogenes spores and exposed to the following surface UV-C fluencies: 0–400 J·m−2 for bacteria and 0–5000 J·m−2 for spores. For the vegetative forms, the highest theoretical lethal UV-C dose, ranging from 670.99 to 688.36 J·m−2 depending on the meal type, was determined for Salmonella. The lowest UV-C fluency of 363.34–363.95 J·m−2 was needed for the inactivation of Enterococcus spp. Spores were considerably more resistant, and the UV-C doses necessary for inactivation were 159571.1 J·m−2 in salmon meal and 66836.9 J·m−2 in cod meal. The application of UV-C radiation for the sanitization of fish meals proved to be a relatively effective method for vegetative forms of bacteria but was practically ineffective for spores. PMID:24578670

  8. UV-C radiation as a factor reducing microbiological contamination of fish meal.

    PubMed

    Skowron, Krzysztof; Bauza-Kaszewska, Justyna; Dobrzański, Zbigniew; Paluszak, Zbigniew; Skowron, Karolina Jadwiga

    2014-01-01

    Fish meals, added to feeds as a source of protein, may contain pathogenic bacteria. Therefore, effective methods for their sanitizing, such as UV-C radiation, are needed to minimize the epidemiological risk. The objective of this study was to evaluate the effect of UV-C radiation on the sanitary state of fish meals. The research materials included salmon and cod meals. Samples of the fish meals were inoculated with suspensions of Salmonella, E. coli, enterococci, and C. sporogenes spores and exposed to the following surface UV-C fluencies: 0-400 J·m⁻² for bacteria and 0-5000 J·m⁻² for spores. For the vegetative forms, the highest theoretical lethal UV-C dose, ranging from 670.99 to 688.36 J·m⁻² depending on the meal type, was determined for Salmonella. The lowest UV-C fluency of 363.34-363.95 J·m⁻² was needed for the inactivation of Enterococcus spp. Spores were considerably more resistant, and the UV-C doses necessary for inactivation were 159571.1 J·m⁻² in salmon meal and 66836.9 J·m⁻² in cod meal. The application of UV-C radiation for the sanitization of fish meals proved to be a relatively effective method for vegetative forms of bacteria but was practically ineffective for spores.

  9. Changes of flavonoid content and antioxidant capacity in blueberries after UV-C illumination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The levels of flavonoids in blueberries were found to increase after illumination with UV-C. Phytochemicals affected included resveratrol, myricetin 3-arabinoside, quercetin 3-galactoside, quercetin derivative, kaempferol derivative, delphinidin-3-galactoside, cyaniding 3-galactoside, delphinidin 3-...

  10. Daily Preharvest UV-C Light Maintains the High Stilbenoid Concentration in Grapes.

    PubMed

    Guerrero, Raúl F; Cantos-Villar, Emma; Puertas, Belén; Richard, Tristan

    2016-06-29

    The fact that it is possible to induce stilbenoid synthesis in grapevine (Vitis vinifera) by UV-C light allows the possibility of stimulating grapevine phytoalexin production to increase disease resistance and immunity, and subsequently to limit the use of pesticides in vineyards. UV-C light was applied daily during three days before the harvesting of table grape variety Crimson seedless to study the accumulation of stilbenoid compounds during ripeness. The E-resveratrol concentration was monitored during daily preharvest UV-C light application and compared with that after a single application. Daily periodic preharvest UV-C light treatment showed a cumulative effect on grape stilbenoids. An 86-fold stilbenoid level increase (sum of E-resveratrol, E-piceatannol, ε-viniferin, E-piceid, isorhapontigenin, ω-viniferin, and Z-piceid) in grapes was achieved. The effects of UV-C light on stilbenoid in grape cane was also addressed for the first time. Stilbenoid oligomers such as hopeaphenol, ampelopsin A, and r-viniferin were quantified in cane samples. Quality grape parameters indicated an acceleration of ripening in UV-C samples.

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

    PubMed

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

    2013-04-15

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

  12. UV-C treatment on physiological response of potato (Solanum tuberosum L.) during low temperature storage.

    PubMed

    Lin, Qiong; Xie, Yajing; Liu, Wei; Zhang, Jie; Cheng, Shuzhen; Xie, Xinfang; Guan, Wenqiang; Wang, Zhidong

    2017-01-01

    The storage of potato tuber (Solanum tuberosum L.) at low temperatures minimizes sprouting and disease but can cause cold-induced sweetening (CIS), which leads to the production of the cancerogenic substance acrylamide during the frying processing. The aim of this research was to investigate the effects of UV-C treatment on CIS in cold stored potato tuber. 'Atlantic' potatoes were treated with UV-C for an hour and then stored at 4 °C up to 28 days. The UV-C treatment significantly prevented the increase of malondialdehyde content (an indicator of the prevention of oxidative injury) in potato cells during storage. The accumulation of reducing sugars, particularly fructose and glucose, was significantly reduced by UV-C treatment possibly due to the regulation of the gene cascade, sucrose phosphate synthase, invertase inhibitor 1/3, and invertase 1 in potato tuber, which were observed to be differently expressed between treated and untreated potatoes during low temperature storage. In summary, UV-C treatment prevented the existence of oxidative injury in potato cells, thus, lowered the amount of reducing sugar accumulation during low temperature storage of potato tubers.

  13. Effect of UV-C light on the microbial and sensory quality of seasoned dried seafood.

    PubMed

    Lee, Eun-Seon; Park, Shin Young; Ha, Sang-Do

    2016-04-01

    This study investigated the effects of different doses of UV-C light at 253.7 nm (0-18 kJ/m(2)) on the reduction of Escherichia coli,Staphylococcus aureus and Bacillus cereus in contaminated seasoned dried filefish (Thamnaconus modestus) and sliced squid (Todarodes pacificus) surfaces and sensory quality. The counts of all three bacteria were significantly (P < 0.05) reduced by the increase of UV-C dosage.E. coli,S. aureus and B. cereus on filefish with 18 kJ/m(2)of UV-C maximally reduced by 2.70, 2.55 and 2.57 log CFU/g, respectively; however, on the sliced squid using the same UV dose reduced the same bacteria by 1.35, 0.54 and 1.05 log CFU/g, respectively. However, the results suggest that 6 to 9 kJ/m(2)of UV-C could be used for the inactivation of E. coli and B. cereus in these dried fishery products without any changes in sensory quality. However, S. aureus levels on sliced squid will require a combination of UV-C light and chemical treatment.

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

    SciTech Connect

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

    1990-05-01

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

  15. Changes in membrane fatty acid composition of Pseudomonas aeruginosa in response to UV-C radiations.

    PubMed

    Ghorbal, Salma Kloula Ben; Chatti, Abdelwaheb; Sethom, Mohamed Marwan; Maalej, Lobna; Mihoub, Mouadh; Kefacha, Sana; Feki, Moncef; Landoulsi, Ahmed; Hassen, Abdennaceur

    2013-07-01

    The changes in lipid composition enable the micro-organisms to maintain membrane functions in the face of environmental fluctuations. The relationship between membrane fatty acid composition and UV-C stress was determined for mid-exponential phase and stationary phase Pseudomonas aeruginosa. The total lipids were obtained by dichloromethane/methanol (3:1) and were quantified by GC. The TLC analysis of phospholipids showed the presence of three major fractions phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Significant modifications, as manifested by an increase of UFA, were obtained. Interestingly, this microorganism showed a remarkable capacity for recovery from the stressful effects of UV-C.

  16. Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV-C radiation.

    PubMed

    Salma, Kloula Ben Ghorbal; Lobna, Maalej; Sana, Khefacha; Kalthoum, Chourabi; Imene, Ouzari; Abdelwaheb, Chatti

    2016-07-01

    It was well known that, UV-C irradiation increase considerably the reactive oxygen species (ROS) levels in eukaryotic and prokaryotic organisms. In the enzymatic ROS-scavenging pathways, superoxide dismutase (SOD), Catalase (CAT), and peroxidase (POX) were developed to deal with oxidative stress. In this study, we investigated the effects of UV-C radiations on antioxidant enzymes (catalase, superoxide dismutase, and peroxidases) expression in Pseudomonas aeruginosa. Catalase, superoxide dismutase, and peroxidases activities were determined spectrophotometrically. Isozymes of superoxide dismutase were revealed by native gel activity staining method. Lipid peroxidation was determined by measuring malondialdehyde formation. Our results showed that superoxide dismutase, catalase and peroxidase activities exhibited a gradual increase during the exposure time (30 min). However, the superoxide dismutase activity was maximized at 15 min. Native gel activity staining assays showed the presence of three superoxide dismutase isozymes. The iron-cofactored isoform activity was altered after exposure to UV-C stress. These finding suggest that catalase and peroxidase enzymes have the same importance toward UV-C rays at shorter and longer exposure times and this may confer additional protection to superoxide dismutase from damage caused by lipid peroxidation. Moreover, our data demonstrate the significant role of the antioxidant system in the resistance of this important human pathogen.

  17. Experimental set up for the irradiation of biological samples and nuclear track detectors with UV C

    PubMed Central

    Portu, Agustina Mariana; Rossini, Andrés Eugenio; Gadan, Mario Alberto; Bernaola, Omar Alberto; Thorp, Silvia Inés; Curotto, Paula; Pozzi, Emiliano César Cayetano; Cabrini, Rómulo Luis; Martin, Gisela Saint

    2016-01-01

    Aim In this work we present a methodology to produce an “imprint” of cells cultivated on a polycarbonate detector by exposure of the detector to UV C radiation. Background The distribution and concentration of 10B atoms in tissue samples coming from BNCT (Boron Neutron Capture Therapy) protocols can be determined through the quantification and analysis of the tracks forming its autoradiography image on a nuclear track detector. The location of boron atoms in the cell structure could be known more accurately by the simultaneous observation of the nuclear tracks and the sample image on the detector. Materials and Methods A UV C irradiator was constructed. The irradiance was measured along the lamp direction and at different distances. Melanoma cells were cultured on polycarbonate foils, incubated with borophenylalanine, irradiated with thermal neutrons and exposed to UV C radiation. The samples were chemically attacked with a KOH solution. Results A uniform irradiation field was established to expose the detector foils to UV C light. Cells could be seeded on the polycarbonate surface. Both imprints from cells and nuclear tracks were obtained after chemical etching. Conclusions It is possible to yield cellular imprints in polycarbonate. The nuclear tracks were mostly present inside the cells, indicating a preferential boron uptake. PMID:26933396

  18. Inactivation kinetics and photoreactivation of vegetable oxidative enzymes after combined UV-C processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The inactivation kinetics of lipoxygenase (LOX), peroxidase (POD) and polyphenoloxidase (PPO) in phosphate buffer (pH 4.0 and 7.0) treated by combined thermal (25-65 C) and UV-C (1-10 min) processes were fitted using a traditional first-order kinetics model and the Weibull distribution function. For...

  19. UV-C Inactivation of Francisella tularensis Utah-112 on agar surfaces, stainless steel, and foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Francisella tularensis has been identified as a microorganism of concern in the field of food security. There is currently very little information on the ability to inactivate F. tularensis on foods using non-thermal processing technologies. The ability of ultraviolet light (UV-C) to inactivate F....

  20. Evaluation of UV-C mutagenized Scheffersomyces stipitis strains for ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated fermentation capabilities of five strains of Scheffersomyces stipitis (WT-2-1, WT-1-11, 14-2-6, 22-1-1, and 22-1-12) that had been produced by UV-C mutagenesis and selection for improved xylose fermentation to ethanol using an integrated automated robotic work cell. They were incubated ...

  1. Alternative strawberry disease management strategy: combing low UV-C irradiation in dark, disabling pathogen’s UV-C repair mechanism, and preventing pathogen establishment with biocontrol agents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The limitations of current fungicides necessitate a search for new approaches. Low-dose or sub-lethal UV-C irradiation (12.36 J/m2) alone is not effective in controlling fungal diseases, especially when the plants are exposed to UV-C irradiation during the day. We found, however, that application ...

  2. UV-C light inactivation kinetics of Penicillium expansum on pear surfaces: Influence on physicochemical and sensory quality during storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postharvest quality and storage life of fresh pear are often limited by fungal growth caused by Penicillium expansum. Ultraviolet-C light (UV-C 254 nm) is a promising alternative disinfestation method to reduce fruit spoilage by fungi. In this study, UV-C inactivation kinetic data of Penicillium exp...

  3. Cyto-genotoxic and oxidative effects of a continuous UV-C treatment of liquid egg products.

    PubMed

    Mendes de Souza, Poliana; Briviba, Karlis; Müller, Alexandra; Fernández, Avelina; Stahl, Mario

    2013-06-01

    UV-C treatment of food is a promising non-thermal processing technology to improve food safety and preservation. Most of the chemical constituents of food absorb UV-C light that can lead to chemical modifications and quality changes. This work investigated the effects of UV-C treatment of liquid egg products on lipid, protein oxidations and potential cyto- and genotoxic effects on intestinal epithelial cells in vitro. Egg preparations (egg white, yolk, liquid whole egg) were treated with UV-C (254 nm, volumetric doses between 0 and 115,619 J L(-1)) using a commercial UV-C processing unit equipped with a Dean Flow reactor. UV-C treatment at high doses (from 32,181 J L(-1), about 2 times higher than that needed to inactivate 5 log of relevant microorganisms) showed an increased lipid oxidation in egg yolk and slight effects in liquid whole eggs; this was confirmed by slightly but not statistically significant increased peroxide values. UV-C induced also slight protein damage, characterised by the total sulfhydryl group reduction. These UV-C-induced oxidative modifications in egg preparations however did not cause any increase in the cyto- or genotoxic (DNA strand breaks) effects in intestinal Caco-2 cells.

  4. Random UV-C mutagenesis of Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yeast strains for anaerobic conversion of lignocellulosic sugars to ethanol were produced from Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 using UV-C mutagenesis. Random UV-C mutagenesis potentially produces large numbers of mutations broadly and uniformly over the whole genome to genera...

  5. Extremely high UV-C radiation resistant microorganisms from desert environments with different manganese concentrations.

    PubMed

    Paulino-Lima, Ivan Glaucio; Fujishima, Kosuke; Navarrete, Jesica Urbina; Galante, Douglas; Rodrigues, Fabio; Azua-Bustos, Armando; Rothschild, Lynn Justine

    2016-10-01

    Desiccation resistance and a high intracellular Mn/Fe ratio contribute to ionizing radiation resistance of Deinococcus radiodurans. We hypothesized that this was a general phenomenon and thus developed a strategy to search for highly radiation-resistant organisms based on their natural environment. While desiccation is a typical feature of deserts, the correlation between radiation resistance and the intracellular Mn/Fe ratio of indigenous microorganisms or the Mn/Fe ratio of the environment, has not yet been described. UV-C radiation is highly damaging to biomolecules including DNA. It was used in this study as a selective tool because of its relevance to early life on earth, high altitude aerobiology and the search for life beyond Earth. Surface soil samples were collected from the Sonoran Desert, Arizona (USA), from the Atacama Desert in Chile and from a manganese mine in northern Argentina. Microbial isolates were selected after exposure to UV-C irradiation and growth. The isolates comprised 28 genera grouped within six phyla, which we ranked according to their resistance to UV-C irradiation. Survival curves were performed for the most resistant isolates and correlated with their intracellular Mn/Fe ratio, which was determined by ICP-MS. Five percent of the isolates were highly resistant, including one more resistant than D. radiodurans, a bacterium generally considered the most radiation-resistant organism, thus used as a model for radiation resistance studies. No correlation was observed between the occurrence of resistant microorganisms and the Mn/Fe ratio in the soil samples. However, all resistant isolates showed an intracellular Mn/Fe ratio much higher than the sensitive isolates. Our findings could represent a new front in efforts to harness mechanisms of UV-C radiation resistance from extreme environments.

  6. S2O8(2-)/UV-C and H2O2/UV-C treatment of Bisphenol A: assessment of toxicity, estrogenic activity, degradation products and results in real water.

    PubMed

    Olmez-Hanci, Tugba; Dursun, Duygu; Aydin, Egemen; Arslan-Alaton, Idil; Girit, Binhan; Mita, Luigi; Diano, Nadia; Mita, Damiano G; Guida, Marco

    2015-01-01

    The performance of S2O8(2-)/UV-C and H2O2/UV-C treatments was investigated for the degradation and detoxification of Bisphenol A (BPA). The acute toxicity of BPA and its degradation products was examined with the Vibrio fischeri bioassay, whereas changes in estrogenic activity were followed with the Yeast Estrogen Screen (YES) assay. LC and LC-MS/MS analyses were conducted to determine degradation products evolving during photochemical treatment. In addition, BPA-spiked real freshwater samples were also subjected to S2O8(2-)/UV-C and H2O2/UV-C treatment to study the effect of a real water matrix on BPA removal and detoxification rates. BPA removal in pure water was very fast (⩽7 min) and complete via both H2O2/UV-C and S2O8(2-)/UV-C treatment, accompanied with rapid and significant mineralization rates ranging between 70% and 85%. V.fischeri bioassay results indicated that degradation products being more toxic than BPA were formed at the initial stages of H2O2/UV-C whereas a rapid and steady reduction in toxicity was observed during S2O8(2-)/UV-C treatment in pure water. UV-C treatment products exhibited a higher estrogenic activity than the original BPA solution while the estrogenicity of BPA was completely removed during H2O2/UV-C and S2O8(2-)/UV-C treatments parallel to its degradation. 3-methylbenzoic and 4-sulfobenzoic acids, as well as the ring opening products fumaric, succinic and oxalic acids could be identified as degradation products. BPA degradation required extended treatment periods (>20 min) and TOC removals were considerably retarded (by 40%) in the raw freshwater matrix most probably due to its natural organic matter content (TOC=5.1 mg L(-1)). H2O2/UV-C and S2O8(2-)/UV-C treatment in raw freshwater did not result in toxic degradation products.

  7. 2-D DIGE analysis of UV-C radiation-responsive proteins in globe artichoke leaves.

    PubMed

    Falvo, Sara; Di Carli, Mariasole; Desiderio, Angiola; Benvenuto, Eugenio; Moglia, Andrea; America, Twan; Lanteri, Sergio; Acquadro, Alberto

    2012-02-01

    Plants respond to ultraviolet stress inducing a self-defence through the regulation of specific gene family members. The UV acclimation is the result of biochemical and physiological processes, such as enhancement of the antioxidant enzymatic system and accumulation of UV-absorbing phenolic compounds (e.g. flavonoids). Globe artichoke is an attractive species for studying the protein network involved in UV stress response, being characterized by remarkable levels of inducible antioxidants. Proteomic tools can assist the evaluation of the expression patterns of UV-responsive proteins and we applied the difference in-gel electrophoresis (DIGE) technology for monitoring the globe artichoke proteome variation at four time points following an acute UV-C exposure. A total of 145 UV-C-modulated proteins were observed and 119 were identified by LC-MS/MS using a ∼144,000 customized Compositae protein database, which included about 19,000 globe artichoke unigenes. Proteins were Gene Ontology (GO) categorized, visualized on their pathways and their behaviour was discussed. A predicted protein interaction network was produced and highly connected hub-like proteins were highlighted. Most of the proteins differentially modulated were chloroplast located, involved in photosynthesis, sugar metabolisms, protein folding and abiotic stress. The identification of UV-C-responsive proteins may contribute to shed light on the molecular mechanisms underlying plant responses to UV stress.

  8. Etiology of UV-C-induced browning in var. Superior white table grapes.

    PubMed

    González-Barrio, Rocío; Salmenkallio-Marttila, Marjatta; Tomás-Barberán, Francisco A; Cantos, Emma; Espín, Juan Carlos

    2005-07-27

    White table grapes, var. Superior, were treated with UV-C light after harvest to increase stilbenes concentration, especially trans-resveratrol (RES), because this may be of relevance to the health-promoting properties assigned to these compounds. However, irradiated grapes also developed some browning on the surface on the third day of storage at 22 degrees C, with the subsequent detriment in the sensorial quality of the fruit. Possible causes for browning development during storage were investigated. The phenolic-related oxidative enzymes, polyphenol oxidase (PPO) and peroxidase (POD), were not specifically activated, and no new isoforms appeared upon UV-C treatment. UV-treated grapes had lower content of chlorophyll b than control grapes on the fourth day of storage, concomitant with the increase of pheophytins (chlorophyll degradation derived compounds). Microscopy data showed lower fluorescence emission in chloroplasts from the UV-treated samples, which may explain the decrease of chlorophylls content in the corresponding grape berries extracts. In addition, microscopy images showed cell wall thickening in the skin tissue of UV-treated grapes which could be considered as a general wound response in plant tissues. These results suggest that the development of browning in Superior white grapes after UV-C treatment is not closely related with the evolution of oxidative enzymes during storage and may be mainly due to the decrease of chlorophylls content.

  9. Resistance of Staphylococcus aureus to UV-C light and combined UV-heat treatments at mild temperatures.

    PubMed

    Gayán, E; García-Gonzalo, D; Alvarez, I; Condón, S

    2014-02-17

    In this investigation, the resistance of enterotoxigenic Staphylococcus aureus to short-wave ultraviolet light (UV-C) and to combined UV C-heat (UV-H) treatments in buffers and in liquid foods with different physicochemical characteristics was studied. Microbial resistance to UV-C varied slightly among the S. aureus strains tested. The UV-C resistance of S. aureus increased in the entry of stationary growth phase, which in part was due to the expression of the alternative sigma factor σ(B). The UV-C resistance of S. aureus was independent of the treatment medium's pH and water activity, but it decreased exponentially as the absorption coefficient increased. UV-C bactericidal efficacy in liquids of high absorption coefficients was improved synergistically when combined with a mild heat treatment at temperatures ranging from 50.0 to 57.5 °C. pH of the treatment medium modified the lethality of UV-H treatments and therefore the temperature of maximum synergy. The advantage of combined UV-H treatments was demonstrated in fruit juices and vegetable and chicken broths, inactivating 5 Log₁₀ cycles of S. aureus by applying UV-C treatments of 27.1 mJ/L for 3.6 min at 52.5 °C or 13.6 mJ/L for 1.8 min at 55.0 °C.

  10. Understanding the physiological effects of UV-C light and exploiting its agronomic potential before and after harvest.

    PubMed

    Urban, Laurent; Charles, Florence; de Miranda, Maria Raquel Alcântara; Aarrouf, Jawad

    2016-08-01

    There is an abundant literature about the biological and physiological effects of UV-B light and the signaling and metabolic pathways it triggers and influences. Much less is known about UV-C light even though it seems to have a lot of potential for being effective in less time than UV-B light. UV-C light is known since long to exert direct and indirect inhibitory and damaging effects on living cells and is therefore commonly used for disinfection purposes. More recent observations suggest that UV-C light can also be exploited to stimulate the production of health-promoting phytochemicals, to extent shelf life of fruits and vegetables and to stimulate mechanisms of adaptation to biotic and abiotic stresses. Clearly some of these effects may be related to the stimulating effect of UV-C light on the production of reactive oxygen species (ROS) and to the stimulation of antioxidant molecules and mechanisms, although UV-C light could also trigger and regulate signaling pathways independently from its effect on the production of ROS. Our review clearly underlines the high potential of UV-C light in agriculture and therefore advocates for more work to be done to improve its efficiency and also to increase our understanding of the way UV-C light is perceived and influences the physiology of plants.

  11. UV-C pre-adaptation of Salmonella: effect on cell morphology and membrane fatty acids composition.

    PubMed

    Maâlej, Lobna; Chatti, Abdelwaheb; Khefacha, Sana; Salma, Kloula; Gottardi, David; Vannini, Lucia; Guerzoni, Maria Elizabetta; Hassen, Abdennaceur

    2014-03-01

    The present study was carried out to evaluate the effects of ultraviolet radiations (UV-C) on the fatty acids composition of three serovars of Salmonella: S. typhimurium, S. hadar and S. zanzibar. Results obtained show that UV-C treatment increases significantly (P ≤ 0.05) the percentage of cyclic fatty acids. The atomic force microscopy was used to study the morphology and cell surface of irradiated strains. Results show that UV-C rays induce morphological changes and alter the bacterial cell surface (presence of grooves and irregularities).

  12. Evaluating UV-C LED disinfection performance and investigating potential dual-wavelength synergy.

    PubMed

    Beck, Sara E; Ryu, Hodon; Boczek, Laura A; Cashdollar, Jennifer L; Jeanis, Kaitlyn M; Rosenblum, James S; Lawal, Oliver R; Linden, Karl G

    2017-02-01

    A dual-wavelength UV-C LED unit, emitting at peaks of 260 nm, 280 nm, and the combination of 260|280 nm together was evaluated for its inactivation efficacy and energy efficiency at disinfecting Escherichia coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores, compared to conventional low-pressure and medium-pressure UV mercury vapor lamps. The dual-wavelength unit was also used to measure potential synergistic effects of multiple wavelengths on bacterial and viral inactivation and DNA and RNA damage. All five UV sources demonstrated similar inactivation of E. coli. For MS2, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was most effective. When measuring electrical energy per order of reduction, the LP UV lamp was most efficient for inactivating E. coli and MS2; the LP UV and MP UV mercury lamps were equally efficient for HAdV2 and B. pumilus spores. Among the UV-C LEDs, there was no statistical difference in electrical efficiency for inactivating MS2, HAdV2, and B. pumilus spores. The 260 nm and 260|280 nm LEDs had a statistical energy advantage for E. coli inactivation. For UV-C LEDs to match the electrical efficiency per order of log reduction of conventional LP UV sources, they must reach efficiencies of 25-39% or be improved on by smart reactor design. No dual wavelength synergies were detected for bacterial and viral inactivation nor for DNA and RNA damage.

  13. Effect of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings

    NASA Astrophysics Data System (ADS)

    Rupiasih, N. Nyoman; Vidyasagar, Pandit B.

    2016-03-01

    An investigation of the effects of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings has been done. The UV-C irradiation periods of exposure were 30, 60, 90, 120 and 180 minutes. The hypergravity used were 1000 g, 2000 g and 2500 g. The combination treatment is UV-C irradiation for 180 min followed by each hypergravity. The results showed that irradiation of UV-C on wheat seeds have stimulated the seed germination, but hypergravity and combination treatments on wheat seeds have inhibited the seed germination. Those treatments gave negative effects to growth rate, the content of chlorophyll a, b and total chlorophyll of wheat seedlings.

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

    PubMed

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

    2014-08-15

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

  15. Rapid induction of omega-3 fatty acids (EPA) in Nannochloropsis sp. by UV-C radiation.

    PubMed

    Sharma, Kalpesh; Schenk, Peer M

    2015-06-01

    Omega-3 fatty acids, such as eicosapentaenoic acid (EPA), provide substantial health benefits. As global fish stocks are declining and in some cases are contaminated with heavy metals, there is a need to find more sustainable land-based sources of these essential fatty acids. The oleaginous microalga Nannochloropsis sp. has been identified as a highly efficient producer of omega-3 fatty acids. In this study, we present a new process to rapidly induce biosynthesis of essential fatty acids, including EPA in Nannochloropsis sp. BR2. Short exposure to UV-C at a dose of 100 or 250 mJ/cm(2) led to a significant increase in total cellular lipid contents when compared to mock-treated controls. A low dosage of 100 mJ/cm(2) also led to a twofold increase in total EPA content within 24 h that constituted 30% of total fatty acids and up to 12% of total dry weight at higher dosages. UV-C radiation may find uses as an easily applicable external inducer for large-scale production of omega-3 production from microalgae.

  16. High reflectivity III-nitride UV-C distributed Bragg reflectors for vertical cavity emitting lasers

    NASA Astrophysics Data System (ADS)

    Franke, A.; Hoffmann, M. P.; Kirste, R.; Bobea, M.; Tweedie, J.; Kaess, F.; Gerhold, M.; Collazo, R.; Sitar, Z.

    2016-10-01

    UV-C distributed Bragg reflectors (DBRs) for vertical cavity surface emitting laser applications and polariton lasers are presented. The structural integrity of up to 25 layer pairs of AlN/Al0.65Ga0.35N DBRs is maintained by balancing the tensile and compressive strain present between the single layers of the multilayer stack grown on top of an Al0.85Ga0.35N template. By comparing the structural and optical properties for DBRs grown on low dislocation density AlN and AlGaN templates, the criteria for plastic relaxation by cracking thick nitride Bragg reflectors are deduced. The critical thickness is found to be limited mainly by the accumulated strain energy during the DBR growth and is only negligibly affected by the dislocations. A reflectance of 97.7% at 273 nm is demonstrated. The demonstrated optical quality and an ability to tune the resonance wavelength of our resonators and microcavity structures open new opportunities for UV-C vertical emitters.

  17. UV-C mediated rapidcarotenoid induction and settling performance of Dunaliellasalina and Haematococcus pluvialis.

    PubMed

    Sharma, Kalpesh K; Ahmed, Faruq; Schenk, Peer M; Li, Yan

    2015-10-01

    Microalgae are primary producers of organic pigments carotenoids in aquatic environments. However, commercial-scale microalgae application for high value carotenoids production is rarely economical due to the cost-effectiveness of carotenoid induction and microalgal harvesting process. Here, we present a novel approach, using a small dose of externally applied UV-C radiation, to rapidly induce unsaturated fatty acids and carotenoid biosynthesis in Dunaliella salina and Haematococcus pluvialis, and also to significantly promote their swimming cells settling for primary dewatering. The amount of total carotenoids and β-carotenoid were doubled in 24 h on D. salina upon 50 mJ/cm(2) of UV-C radiation, whereas the astaxanthin yield of H. pluvialis was increased five times in 48 h at 30 mJ/cm(2) . Meanwhile, 95% of algal cells of D. salina and H. pluvialis settled in 15 h and 2 h, respectively. This novel technique represents a convenient, time-saving and cost-effective method for commercial microalgal carotenoids production.

  18. Efficient removal of endosulfan from aqueous solution by UV-C/peroxides: a comparative study.

    PubMed

    Shah, Noor S; He, Xuexiang; Khan, Hasan M; Khan, Javed Ali; O'Shea, Kevin E; Boccelli, Dominic L; Dionysiou, Dionysios D

    2013-12-15

    This study explored the efficiency of UV-C-based advanced oxidation processes (AOPs), i.e., UV/S2O8(2-), UV/HSO5(-), and UV/H2O2 for the degradation of endosulfan, an organochlorine insecticide and an emerging water pollutant. A significant removal, 91%, 86%, and 64%, of endosulfan, at an initial concentration of 2.45 μM and UV fluence of 480 mJ/cm(2), was achieved by UV/S2O8(2-), UV/HSO5(-), and UV/H2O2 processes, respectively, at a [peroxide]0/[endosulfan]0 molar ratio of 20. The efficiency of these processes was, however, inhibited in the presence of radical scavengers, such as alcohols (e.g., tertiary butyl alcohol and isopropyl alcohol) and natural organic matter (NOM). The inhibition was also influenced by common inorganic anions in the order of nitrite > bicarbonate > chloride > nitrate ≈ sulfate. The observed pseudo-first-order rate constant decreased while the degradation rate increased with increasing initial concentration of the target contaminant. The degradation mechanism of endosulfan by the AOPs was evaluated revealing the main by-product as endosulfan ether. Results of this study suggest that UV-C-based AOPs are potential methods for the removal of pesticides, such as endosulfan and its by-products, from contaminated water.

  19. Inactivation of Penicillium digitatum and Penicillium italicum under in vitro and in vivo conditions by using UV-C light.

    PubMed

    Gündüz, Gülten Tıryakı; Pazir, Fikret

    2013-10-01

    In this study, the effects of UV-C on two of the main wound pathogens of citrus fruits, Penicillium digitatum and Penicillium italicum, were investigated with different inoculation methods in vitro and on oranges. P. digitatum and P. italicum spores were inoculated onto the surface of potato dextrose agar or oranges using spread, spot, wound, and piercing inoculation methods. UV-C treatment for 1 min from a working distance of 8 cm reduced the numbers of P. italicum and P. digitatum by about 3.9 and 5.3 log units, respectively, following spread inoculation under in vitro conditions. Significant reductions were obtained after 1-min UV-C treatments of the tested fungi following inoculation using the spread and spot methods. With inoculation by the wound and piercing methods, the tested spores were not inactivated completely even after 10- and 20-min treatment times, respectively. The application of UV-C (7.92 kJ m(-2)) on oranges reduced the percentage of oranges infected at least threefold compared with the rate of infection in the untreated control samples. UV-C irradiation could effectively inactivate spores of P. italicum and P. digitatum inoculated by the spread plate and spot inoculation methods under in vitro and in vivo conditions. On the other hand, because of the low penetration ability of UV-C light, the tested fungi were not completely inactivated following inoculation with the wound and piercing methods. UV-C treatment has potential for use in surface decontamination of citrus fruits.

  20. [Corn plant DNA methylation pattern changes upon fractional UV-C irradiation].

    PubMed

    Kravets, A P; Sokolova, D A; Vengzhen, G S; Grodzinskiĭ, D M

    2013-01-01

    Relationship of changes of methylation pattern of functionally different parts of DNA and chromosomal aberration yield was studied at the conditions of the fractionating of UV-C irradiation. Combination of restriction analysis (Hpall, MspI, MboI enzymes) with the subsequent raising of PCR (internal transcribed space ITS1, 1TS4 and inter simple sequence repeat - ISSR, 14b primers) was used. The got results testify to the changes in methylation pattern of satellite and transcription active part of DNA atan irradiation in the mode of fractionating and depending on fraction time ranges. The role of the methylation DNA pattern change in development of radiation damage and induction of organism protective reactions was discussed.

  1. Postharvest physio-pathological disorders in table grapes as affected by UV-C light.

    PubMed

    D'Hallewin, G; Ladu, G; Pani, G; Dore, A; Molinu, M G; Venditti, T

    2012-01-01

    To gain knowledge on the influence of postharvest treatments with ultraviolet-C light upon the keeping quality of table grapes, a trail was performed employing commercially mature 'Corina', 'Dawn Seedless', 'Centennial Seedless' and 'Gran Perlon' grape cultivars (cvs). After grading, bunches were subjected to 0.0, 0.5, 1.5 or 3 kJm(-2) and then stored at 5 degrees C and 90% relative humidity (RH) for 6 weeks followed by a 2 day shelf-life at 25 degrees C and 70% RH. A weekly inspection was performed and a visual evaluation of the appearance, treatment damage, stems browning and berry shrivelling was performed. Weight loss, decay and shatter were quantified at the end of storage and shelf-life. Regardless the cv and UV-C dose, fruit appearance was acceptable until the end of storage and shelf-life. Among the cvs, the highest score was held by 'G. Perlon'. After the fourth week of storage, the berries of 'Centennial S.' turned light brown and darkened over time when treated with 3.0 kJm(-2). Stem browning was not induced by the light treatment, but resulted cv depended and was pronounced for 'Centennial S.' and 'Dawn S.'. Berry shrivelling was insignificant, while shatter was very high in 'Corina' and did not depend upon UV-C treatment. Regarding weight loss, differences could not be attributed to the light treatment and after storage it ranged from 3 up to 5%. Decay was significantly reduced by light treatment and the efficacy increased by raising the dose. Botrytis cinerea was the main cause of decay with 'Corina' being the most jeopardized, followed by 'Dawn S.' and 'Centennial S.', whereas 'G. Perlon' resulted the less affected. In conclusion, hormetic effects of postharvest light treatment on table grapes were observed in almost all cvs with 'G. Perlon' having the best performance.

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

    PubMed

    Guo, Dongqi; Zhu, Lixia; Hou, Xujie

    2015-01-01

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

  3. Hyperspectral Surface Analysis for Ripeness Estimation and Quick UV-C Surface Treatments for Preservation of Bananas

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Yang, Zh.; Chen, Zh.; Liu, J.; Wang, W. Ch.; Zheng, W. Yu.

    2016-05-01

    This study aimed to determine the ripeness of bananas using hyperspectral surface analysis and how a rapid UV-C (ultraviolet-C light) surface treatment could reduce decay. The surface of the banana fruit and its stages of maturity were studied using a hyperspectral imaging technique in the visible and near infrared (370-1000 nm) regions. The vselected color ratios from these spectral images were used for classifying the whole banana into immature, ripe, half-ripe and overripe stages. By using a BP neural network, models based on the wavelengths were developed to predict quality attributes. The mean discrimination rate was 98.17%. The surface of the fresh bananas was treated with UV-C at dosages from 15-55 μW/cm2. The visual qualities with or without UV-C treatment were compared using the image, the chromatic aberration test, the firmness test and the area of black spot on the banana skin. The results showed that high dosages of UV-C damaged the banana skin, while low dosages were more efficient at delaying changes in the relative brightness of the skin. The maximum UV-C treatment dose for satisfactory banana preservation was between 21 and 24 μW/cm2. These results could help to improve the visual quality of bananas and to classify their ripeness more easily.

  4. Abscisic acid induces biosynthesis of bisbibenzyls and tolerance to UV-C in the liverwort Marchantia polymorpha.

    PubMed

    Kageyama, Akito; Ishizaki, Kimitsune; Kohchi, Takayuki; Matsuura, Hideyuki; Takahashi, Kosaku

    2015-09-01

    Environmental stresses are effective triggers for the biosynthesis of various secondary metabolites in plants, and phytohormones such as jasmonic acid and abscisic acid are known to mediate such responses in flowering plants. However, the detailed mechanism underlying the regulation of secondary metabolism in bryophytes remains unclear. In this study, the induction mechanism of secondary metabolites in the model liverwort Marchantia polymorpha was investigated. Abscisic acid (ABA) and ultraviolet irradiation (UV-C) were found to induce the biosynthesis of isoriccardin C, marchantin C, and riccardin F, which are categorized as bisbibenzyls, characteristic metabolites of liverworts. UV-C led to the significant accumulation of ABA. Overexpression of MpABI1, which encodes protein phosphatase 2C (PP2C) as a negative regulator of ABA signaling, suppressed accumulation of bisbibenzyls in response to ABA and UV-C irradiation and conferred susceptibility to UV-C irradiation. These data show that ABA plays a significant role in the induction of bisbibenzyl biosynthesis, which might confer tolerance against UV-C irradiation in M. polymorpha.

  5. The reduction of Chlorella vulgaris concentrations through UV-C radiation treatments: A nature-based solution (NBS).

    PubMed

    Chen, Erika S; Bridgeman, Thomas B

    2017-03-25

    Algal blooms have become a pressing issue in inland freshwater systems on local and global scales. A plausible approach to reducing algae without the use of chemical/biological agents is through the use of UV-C radiation from lamps potentially powered by in situ solar panels to eliminate algae. Yet, the quantitative scientific base has not been established. Our objective is to conduct a controlled experiment to quantify the effectiveness of UV-C radiation on the reduction of Chlorella vulgaris, a common algal species in the Great Lakes region. A full factorial design of three intensities of UV-C radiation (0, 15, and 30W) and three sources of C. vulgaris was constructed to test the corresponding hypotheses. Empirical models were constructed to predict the reductions. UV-C radiation effectively reduced the algal concentration with clear differences by radiation level and source of algal water. Algal concentration decreased exponentially over time, with distinct decreasing trends among the radiation intensities and the samples. With 15W UV-C radiation, algal concentration of three samples were reduced to 75.3%, 51.5%, and 70.0% of the initial level within an hour, respectively. We also found a clear density-dependent reduction rate by UV radiation. Using this information, more efficient treatment systems could be constructed and implemented for cleaning algae-contaminated water.

  6. Nitrifying-denitrifying filters and UV-C disinfection reactor: a combined system for wastewater treatment.

    PubMed

    Ben Rajeb, Asma; Mehri, Inès; Nasr, Houda; Najjari, Afef; Saidi, Neila; Hassen, Abdennaceur

    2017-03-01

    Biological treatment systems use the natural processes of ubiquitous organisms to remove pollutants and improve the water quality before discharge to the environment. In this paper, the nitrification/denitrification reactor allowed a reduction in organic load, but offered a weak efficiency in nitrate reduction. However, the additions of the activated sludge in the reactor improve this efficiency. A decrease of [Formula: see text] values from 13.3 to 8 mg/l was noted. Nevertheless, sludge inoculation led to a net increase of the number of pathogenic bacteria. For this reason, a UV-C pilot reactor was installed at the exit of the biological nitrification-denitrification device. Thus, a fluence of 50 mJ.cm(-2) was sufficient to achieve values of 20 MPN/100 ml for fecal coliform and 6 MPN/100 ml for fecal streptococci, conforms to Tunisian Standards of Rejection. On the other hand, the DGGE approach has allowed a direct assessment of the bacterial community changes upon the treated wastewater.

  7. NER and HR pathways act sequentially to promote UV-C-induced germ cell apoptosis in Caenorhabditis elegans

    PubMed Central

    Stergiou, L; Eberhard, R; Doukoumetzidis, K; Hengartner, M O

    2011-01-01

    Ultraviolet (UV) radiation-induced DNA damage evokes a complex network of molecular responses, which culminate in DNA repair, cell cycle arrest and apoptosis. Here, we provide an in-depth characterization of the molecular pathway that mediates UV-C-induced apoptosis of meiotic germ cells in the nematode Caenorhabditis elegans. We show that UV-C-induced DNA lesions are not directly pro-apoptotic. Rather, they must first be recognized and processed by the nucleotide excision repair (NER) pathway. Our data suggest that NER pathway activity transforms some of these lesions into other types of DNA damage, which in turn are recognized and acted upon by the homologous recombination (HR) pathway. HR pathway activity is in turn required for the recruitment of the C. elegans homolog of the yeast Rad9-Hus1-Rad1 (9-1-1) complex and activation of downstream checkpoint kinases. Blocking either the NER or HR pathway abrogates checkpoint pathway activation and UV-C-induced apoptosis. Our results show that, following UV-C, multiple DNA repair pathways can cooperate to signal to the apoptotic machinery to eliminate potentially hazardous cells. PMID:21151025

  8. UV-C inactivation of Escherichia coli and dose uniformity on apricot fruit in a commercial setting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacy of a UV-C treatment system (two treatment chambers connected by an inclined belt to rotate apricots between chambers) was tested in a commercial setting. Escherichia coli ATCC 25922, used as a surrogate for E. coli O157:H7 to determine the system’s antimicrobial efficacy, was inoculate...

  9. Factors driving epilithic algal colonization in show caves and new insights into combating biofilm development with UV-C treatments.

    PubMed

    Borderie, Fabien; Tête, Nicolas; Cailhol, Didier; Alaoui-Sehmer, Laurence; Bousta, Faisl; Rieffel, Dominique; Aleya, Lotfi; Alaoui-Sossé, Badr

    2014-06-15

    The proliferation of epilithic algae that form biofilms in subterranean environments, such as show caves, is a major problem for conservators. In an effort to reduce the use of chemical cleansers when addressing this problem, we proposed investigating the effects of UV-C on combating algal biofilm expansion in a cave located in northeastern France (Moidons Cave). First, the biofilms and cavity were studied in terms of their algal growth-influencing factors to understand the dynamics of colonization in these very harsh environments. Next, colorimetric measurements were used both to diagnose the initial colonization state and monitor the UV-C-treated biofilms for several months after irradiation. The results indicated that passive dispersal vectors of the viable spores and cells were the primary factors involved in the cave's algae repartition. The illumination time during visits appeared to be responsible for greater colonization in some parts of the cave. We also showed that colorimetric measurements could be used for the detection of both thin and thick biofilms, regardless of the type of colonized surface. Finally, our results showed that UV-C treatment led to bleaching of the treated biofilm due to chlorophyll degradation even one year after UV-C treatment. However, a re-colonization phenomenon was colorimetrically and visually detected 16months later, suggesting that the colonization dynamics had not been fully halted.

  10. Kinetics of inactivation and photoreactivation of Escherichia coli using ultrasound-enhanced UV-C light-emitting diodes disinfection.

    PubMed

    Zhou, Xiaoqin; Li, Zifu; Lan, Juanru; Yan, Yichang; Zhu, Nan

    2017-03-01

    Ultraviolet (UV) disinfection is highly recommended owing to its high disinfection efficiency and disinfection by-products free, and UV Light-Emitting Diodes (UV LEDs) is increasingly becoming an alternative of mercury UV lamps for water disinfection owing to its long lifetime, low input power, and absence of problems on disposal. However, renovation of existing UV lamps faces the challenges for UV disinfection associated with disinfection efficiency and photoreactivation, and modified UV disinfection process is required for practical application. In this study, mathematical rule of disinfection and photoreactivation in a US enhanced UV disinfection system was investigated. UV LED with peak emission at 254nm (UV-C LED) was selected as representative for UV lamps, and a low frequency US was used as pretreatment followed by UV disinfection. The disinfection efficiency of Escherichia coli in deionized water (DI), DI water with kaoline suspension (DIK), and secondary effluent (SE) of municipal wastewater treatment plant were analyzed. Moreover, photoreactivation of E. coli in DIK water within 6h after disinfection was conducted. The experimental results showed that the disinfection efficiencies had good fit with Chick-Watson first-order linear model, and US pretreatment increased the inactivation rate constant for E. coli, which increased from 0.1605 to 0.1887 in the DIK water. Therefore, US pretreatment with UV disinfection have potential to shorten the retention time and reduce the reactor volume. Moreover, the number of photoreactivated E. coli in effluent was reduced under UV-C LED disinfection with US pretreatment compared with that under UV-C LED disinfection alone. The order of maximum percentage of photo-reactivated E. coli was as follows: UV-C LED disinfection alone at 30mJ/cm(2)>UV-C LED disinfection at 25mJ/cm(2) with US pretreatment>UV-C LED disinfection at 30mJ/cm(2) with US pretreatment. The survival ratio versus photoreactivation time showed a good fit

  11. Responsiveness of Lycopersicon pimpinellifolium to acute UV-C exposure: histo-cytochemistry of the injury and DNA damage.

    PubMed

    Iriti, M; Guarnieri, S; Faoro, F

    2007-01-01

    The in vivo and in vitro effects of UV-C (254 nm) exposure (0.039 watt . m(-2) . s for 2 h) of currant tomato (Lycopersicon pimpinellifolium), indigenous to Peru and Ecuador, were assayed. H(2)O(2) deposits, dead cells and DNA damage were localized, 12/24 h after irradiation, mainly in periveinal parenchyma of the 1st and 2nd order veins of the leaves, and before the appearance of visible symptoms, which occurred 48 h after irradiation. Cell death index was of 43.5 +/- 12% in exposed leaf tissues, 24 h after treatment. In currant tomato protoplasts, the percentage of viable cells dropped 1 h after UV-C irradiation from 97.42 +/- 2.1% to 43.38 +/- 4.2%. Afterwards, the protoplast viability progressively decreased to 40.16 +/- 7.25% at 2 h, to 38.31 +/- 6.9% at 4 h, and to 36.46 +/- 1.84% at 6 h after the exposure. The genotoxic impact of UV-C radiation on protoplasts was assessed with single cell gel electrophoresis (SCGE, or comet assay). UV-C treatment greatly enhanced DNA migration, with 75.37 +/- 3.7% of DNA in the tail versus 7.88 +/- 5.5% in the case of untreated nuclei. Oxidative stress by H(2)O(2) used as a positive control, induced a similar damage on non-irradiated protoplasts, with 71.59 +/- 5.5% of DNA in the tail, whereas oxidative stress imposed on UV-C irradiated protoplasts slightly increased the DNA damage (85.13 +/- 4.1%). According to these results, SCGE of protoplasts could be an alternative to nuclei extraction directly from leaf tissues.

  12. Salt stress mitigation by seed priming with UV-C in lettuce plants: growth, antioxidant activity and phenolic compounds.

    PubMed

    Ouhibi, Chayma; Attia, Houneida; Rebah, Fedia; Msilini, Najoua; Chebbi, Mohamed; Aarrouf, Jawad; Urban, Laurent; Lachaal, Mokhtar

    2014-10-01

    Seeds of Lactuca sativa L. 'Romaine' were subjected to priming treatments with UV-C radiation at 0.85 or 3.42 kJ m(-2). Seedlings obtained from both primed (Pr) and non-primed (NPr) seeds were grown in an hydroponic culture system supplemented with 0 (control) or 100 mM NaCl. After 21 days of NaCl treatment, root and leaf biomass, root lengths, leaf numbers, and leaf surface area were measured. Ions (Na(+) and K(+)) accumulation was determined in roots and leaves. Total phenolic compound and flavonoid concentrations, as well as antioxidant and antiradical activities were measured in L. sativa leaves. Salt stress resulted in a lower increase in fresh weight of roots and leaves, which was more pronounced in roots than in leaves, due to reduced root elongation, leaf number and leaf expansion, as well as leaf thickness. The lower increase in fresh weight was accompanied by a restriction in tissue hydration and K(+) ion uptake, as well as an increase in Na(+) ion concentrations in all organs. These effects were mitigated in plants from the UV-C primed seeds. The mitigating effect of UV-C was more pronounced at 0.85 than at 3.42 kJ m(-2). Salt stress also resulted in an increase in total phenolic compounds and flavonoid concentrations and in the total antioxidant capacity in leaves. The highest diphenylpicrylhydrazyl radical (DPPH) scavenging activity was found in the leaves of plants from both Pr seeds. Our results suggest that plants grown from seed primed by exposure to moderate UV-C radiation exhibited a higher tolerance to salinity stress.

  13. The response of aggregated Pseudomonas putida CP1 cells to UV-C and UV-A/B disinfection.

    PubMed

    Maganha de Almeida, Ana C; Quilty, Bríd

    2016-11-01

    UV radiation is a spread method used worldwide for the disinfection of water. However, much of the research on the disinfection of bacterial cells by UV has focused on planktonic cells. Many bacterial cells in nature are present in clumps or aggregates, and these aggregates, which are more resistant to disinfection than their planktonic counterparts, can be problematic in engineered water systems. The current research used Pseudomonas putida (P. putida) CP1, an environmental and non-pathogenic microorganism which autoaggregates when grown under certain conditions, as a model organism to simulate aggregated cells. The study investigated the response of both the planktonic and the aggregated forms of the bacterium to UV-C (λ = 253.7 nm) and UV-A/B (λ > 300 nm) disinfection at laboratory scale in a minimal medium. The planktonic cells of P. putida CP1 were inactivated within 60 s by UV-C and in 60 min by UV-A/B; however, the aggregated cells required 120 min of UV-C treatment and 240 min of UV-A/B radiation to become inactive. The size of the aggregate was reduced following UV treatment. Although all the cells had lost culturability, viability as measured by the LIVE/DEAD(®) stain and epifluorescence microscopy was not completely lost and the cells all demonstrated regrowth after overnight incubation in the dark.

  14. Photolytic degradation of sulfamethoxazole and trimethoprim using UV-A, UV-C and vacuum-UV (VUV).

    PubMed

    Kim, Hyun Young; Kim, Tae-Hun; Yu, Seungho

    2015-01-01

    The photolytic degradation of the non-degradable pharmaceuticals sulfamethoxazole (SMX) and trimethoprim (TMP) in an aqueous solution was investigated using three kinds of low-pressure mercury lamp UV-A (352 nm), UV-C (254 nm), and vacuum-UV (VUV, 185 nm and 254 nm). The degradation rates were highly dependent on the target compounds as well as the UV sources. No degradation of the target compounds was observed using UV-A treatment, because there was no overlap between the UV-A emission spectrum and absorption spectrum of the target compounds. On the other hand, UVC and VUV revealed higher reactivity. The results also indicated that SMX had a greater potential to react photochemically than TMP. Among the UV sources, VUV was the most effective process for the degradation of target compounds. Furthermore, the addition of oxidants such as hydrogen peroxide (H2O2) and sodium persulfate (Na2S2O8) to the reaction system improved the overall degradation rate significantly.The experimental results for the VUV-irradiated samples with the addition of methanol as a hydroxyl radical scavenger revealed that hydroxyl radicals contribute significantly to the elimination of the target compound. Overall, the degradation rate of the target compounds was in the order: VUV = UV-C > UV-A for sulfamethoxazole and VUV/H2O2 > VUV/ Na2S2O8 > VUV >UV-C >UV-A for trimethoprim.

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

    PubMed

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

    2016-01-01

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

  16. Fatty Acids Composition and Biofilm Production of Attenuated Salmonella typhimurium dam and seqA Mutants After Exposure to UV-C.

    PubMed

    Abdelwaheb, Chatti; Lobna, Maalej; Bouchra, BelHadj Abdallah; Selma, Kloula; Ahmed, Landoulsi

    2015-10-01

    The goal of this work was the investigation of correlation between some peculiarities of membrane fatty acids composition, biofilm formation, and motility of dam and/or seqA mutants in Salmonella typhimurium bacterial cells and UV-C radiations. The exposure changed the fatty acids composition of dam and seqA/dam strains. Significant increase of unsaturated fatty acids was observed. Swarming and swimming were enhanced only in dam mutant and biofilm formation increased significantly in all tested strains after UV-C exposure. These results suggest that increased sensitivity toward UV-C rays in dam strains might be due to fatty acid alteration.

  17. A synergistic effect in controlling plum postharvest diseases occurs by applying UV-C light to sodium bicarbonate treated fruit.

    PubMed

    D'Hallewin, G; Cubaiu, L; Ladu, G; Venditti, T

    2013-01-01

    The effectiveness of ultraviolet-C light (UV-C; 254 nm) alone at 0, 3, 6 and 12 kJm(-2), or combined with 0.0 or 0.5% (w7v) sodium bicarbonate (SBC), to control plum (Prunus domestica cv Stanley) postharvest decay caused by Penicillium expansum L. and Botrytis cinerea was investigated. First, fruit was sanitized and in one experiment plums were artificially wound-inoculated 24 h before treatments and afterwards kept at 25 degrees C with 90% RH for 7 days. In the second experiment, treatments were applied before fruit was spray-contaminated with conidia and then stored for 4 weeks at 5 degrees C and 90% RH (storage conditions). In both experiments, the highest degree of decay caused by the two pathogens was monitored when fruit stayed untreated (control), and a negligible reduction was achieved by treating with the sole salt or with a 3 kJm(-2) UV-C light. Compared to control (89 +/- 3% decay), the treatment of wound-inoculated fruit with 6 kJm(-2) provided a 35 and 38% reduction of P. expansum and B. cinerea decay, respectively. Meanwhile, 12 kJm(-2) provided an additional decrease of 25 and 27%, respectively. In both experiments, the best control of decay was attained when treatments with SBC and UV-C light were combined and the efficacy depended upon the sequence of application. Synergistic effects were found by applying the salt before UV-C light. When 6 or 12 kJm(-2) were employed following the 2% SBC treatment, no disease symptoms developed for either pathogens in both experiments. The same combination with 3 kJm(-2) resulted in a nearly 5 fold increase of efficacy compared to the sole light treatment. The combined treatments controlled the two pathogens to valuable levels and, since no quality losses were observed during storage, they could be considered as a suitable approach to contain postharvest losses of this fruit.

  18. Enhancing the Total Phenolic Content and Antioxidants of Lemon Pomace Aqueous Extracts by Applying UV-C Irradiation to the Dried Powder.

    PubMed

    Papoutsis, Konstantinos; Vuong, Quan V; Pristijono, Penta; Golding, John B; Bowyer, Michael C; Scarlett, Christopher J; Stathopoulos, Costas E

    2016-08-23

    Several studies have shown that UV-C (ultraviolet C) irradiation promotes the bioactive compounds and antioxidants of fresh fruits and vegetables. The aim of this study was to apply UV irradiation in dried lemon pomace powder for enhancing its phenolic content and antioxidant properties, thus more bioactive compounds should be available for extraction and utilization. Lemon pomace dried powder was placed under a UV lamp and treated with dosages of 4, 19, 80 and 185 kJ·m(-2), while untreated powder was used as a control. UV-C irradiation significantly affected the total phenolic content, total flavonoid content, proanthocyanidins, and antioxidant capacity measured by cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) of the lemon pomace dried powder, while it did not affect the vitamin C content. UV-C irradiation of 19 kJ·m(-2) resulted in 19% higher total phenolic content than the control, while UV-C irradiation of 180 kJ·m(-2) resulted in 28% higher total flavonoid content than the control. The antioxidant capacity was reduced when UV-C irradiation more than 4 kJ·m(-2) was applied. The results of this study indicate that UV-C treatment has the potential to increase the extraction of bioactive compounds of dried lemon pomace at relatively high dosages.

  19. Enhancing the Total Phenolic Content and Antioxidants of Lemon Pomace Aqueous Extracts by Applying UV-C Irradiation to the Dried Powder

    PubMed Central

    Papoutsis, Konstantinos; Vuong, Quan V.; Pristijono, Penta; Golding, John B.; Bowyer, Michael C.; Scarlett, Christopher J.; Stathopoulos, Costas E.

    2016-01-01

    Several studies have shown that UV-C (ultraviolet C) irradiation promotes the bioactive compounds and antioxidants of fresh fruits and vegetables. The aim of this study was to apply UV irradiation in dried lemon pomace powder for enhancing its phenolic content and antioxidant properties, thus more bioactive compounds should be available for extraction and utilization. Lemon pomace dried powder was placed under a UV lamp and treated with dosages of 4, 19, 80 and 185 kJ·m−2, while untreated powder was used as a control. UV-C irradiation significantly affected the total phenolic content, total flavonoid content, proanthocyanidins, and antioxidant capacity measured by cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) of the lemon pomace dried powder, while it did not affect the vitamin C content. UV-C irradiation of 19 kJ·m−2 resulted in 19% higher total phenolic content than the control, while UV-C irradiation of 180 kJ·m−2 resulted in 28% higher total flavonoid content than the control. The antioxidant capacity was reduced when UV-C irradiation more than 4 kJ·m−2 was applied. The results of this study indicate that UV-C treatment has the potential to increase the extraction of bioactive compounds of dried lemon pomace at relatively high dosages. PMID:28231150

  20. Preliminary evidence on photoreactivation of Frankia spores with visible light after exposure to UV-C radiation.

    PubMed

    Sayed, W F

    2011-06-01

    Spores of four Frankia strains, the nitrogen-fixing actinomycete, were exposed to short wavelength UV-C radiation of 254 nm at 1 lux cm(2) (0.24 mw cm2 of energy) for 10 min. The used strains were HFP020203, UGL020604, UGL020602q and ORS021001. Exposure to UV was followed by reactivation with visible white light at 327.4 lux cm(2) for the same period of time. Spore germination percentage, spore protein content, and cell growth were damaged by this treatment. The lower and higher percentages of reduction in spore germination were 32 and 63% and, for the same strains, the recovery by white light was 7.2 and 37%. The lower percentages of UV damage and subsequent low recovery were recorded for strain ORS021001 that is considered more resistant to UV than the other strains. The higher percentages were recorded for strain HFP020203 that is more sensitive to UV but having more efficient repairing mechanisms. All the tested strains showed repairing activity induced by white light as indicated from the increase in their spore germination, protein content and almost restoring the normal shape of Frankia hyphae, after being damaged, as revealed by scanning electron microscope. This is the first evidence that photo-repairing systems are present in Frankia strains although there are variations in their response to both UV-C and photoreactivation by white light.

  1. UV-C light inactivation and modeling kinetics of Alicyclobacillus acidoterrestris spores in white grape and apple juices.

    PubMed

    Baysal, Ayse Handan; Molva, Celenk; Unluturk, Sevcan

    2013-09-16

    In the present study, the effect of short wave ultraviolet light (UV-C) on the inactivation of Alicyclobacillus acidoterrestris DSM 3922 spores in commercial pasteurized white grape and apple juices was investigated. The inactivation of A. acidoterrestris spores in juices was examined by evaluating the effects of UV light intensity (1.31, 0.71 and 0.38 mW/cm²) and exposure time (0, 3, 5, 7, 10, 12 and 15 min) at constant depth (0.15 cm). The best reduction (5.5-log) was achieved in grape juice when the UV intensity was 1.31 mW/cm². The maximum inactivation was approximately 2-log CFU/mL in apple juice under the same conditions. The results showed that first-order kinetics were not suitable for the estimation of spore inactivation in grape juice treated with UV-light. Since tailing was observed in the survival curves, the log-linear plus tail and Weibull models were compared. The results showed that the log-linear plus tail model was satisfactorily fitted to estimate the reductions. As a non-thermal technology, UV-C treatment could be an alternative to thermal treatment for grape juices or combined with other preservation methods for the pasteurization of apple juice.

  2. Efficacy of Ultraviolet (UV-C) Light in a Thin-Film Turbulent Flow for the Reduction of Milkborne Pathogens.

    PubMed

    Crook, Jennifer A; Rossitto, Paul V; Parko, Jared; Koutchma, Tatiana; Cullor, James S

    2015-06-01

    Nonthermal technologies are being investigated as viable alternatives to, or supplemental utilization, with thermal pasteurization in the food-processing industry. In this study, the effect of ultraviolet (UV)-C light on the inactivation of seven milkborne pathogens (Listeria monocytogenes, Serratia marcescens, Salmonella Senftenberg, Yersinia enterocolitica, Aeromonas hydrophila, Escherichia coli, and Staphylococcus aureus) was evaluated. The pathogens were suspended in ultra-high-temperature whole milk and treated at UV doses between 0 and 5000 J/L at a flow rate of 4300 L/h in a thin-film turbulent flow-through pilot system. Of the seven milkborne pathogens tested, L. monocytogenes was the most UV resistant, requiring 2000 J/L of UV-C exposure to reach a 5-log reduction. The most sensitive bacterium was S. aureus, requiring only 1450 J/L to reach a 5-log reduction. This study demonstrated that the survival curves were nonlinear. Sigmoidal inactivation curves were observed for all tested bacterial strains. Nonlinear modeling of the inactivation data was a better fit than the traditional log-linear approach. Results obtained from this study indicate that UV illumination has the potential to be used as a nonthermal method to reduce microorganism populations in milk.

  3. Effects of ultraviolet light (UV-C) and heat treatment on the quality of fresh-cut Chokanan mango and Josephine pineapple.

    PubMed

    George, Dominic Soloman; Razali, Zuliana; Santhirasegaram, Vicknesha; Somasundram, Chandran

    2015-02-01

    The effects of ultraviolet (UV-C) and medium heat (70 °C) treatments on the quality of fresh-cut Chokanan mango and Josephine pineapple were investigated. Quality attributes included physicochemical properties (pH, titratable acidity, and total soluble solids), ascorbic acid content (vitamin C), antioxidant activity, as well as microbial inactivation. Consumers' acceptance was also investigated through sensory evaluation of the attributes (appearance, texture, aroma and taste). Furthermore, shelf-life study of samples stored at 4 ± 1 °C was conducted for 15 d. The fresh-cut fruits were exposed to UV-C for 0, 15, 30, and 60 min while heat treatments were carried out at 70 °C for 0, 5, 10 and 20 min. Both UV-C and medium heat treatments resulted in no significant changes to the physicochemical attributes of both fruits. The ascorbic acid content of UV-C treated fruits was unaffected; however, medium heat treatment resulted in deterioration of ascorbic acids in both fruits. The antioxidants were enhanced with UV-C treatment which could prove invaluable to consumers. Heat treatments on the other hand resulted in decreased antioxidant activities. Microbial count in both fruits was significantly reduced by both treatments. The shelf life of the fresh-cut fruits were also successfully extended to a maximum of 15 d following treatments. As for consumers' acceptance, UV-C treated fruits were the most accepted as compared to their heat-treated counterparts. The results obtained through this study support the use of UV-C treatment for better retention of quality, effective microbial inactivation and enhancement of health promoting compounds for the benefit of consumers.

  4. Gamma-irradiation and UV-C light-induced lipid peroxidation: a Fourier transform-infrared absorption spectroscopic study.

    PubMed

    Kinder, R; Ziegler, C; Wessels, J M

    1997-05-01

    Fourier transform-infrared spectroscopy of dry, multibilayer films has been used to study gamma-radiation and UV-C light induced lipid peroxidation in 1,2-dilinoleoyl-sn-glycero-3-phosphocholine liposomes. The observed spectral changes were compared with the results obtained from measurement of hydroperoxides, conjugated dienes and to the formation of thiobarbituric acid reactive substances, such as malondialdehyde (MDA) or MDA-like substances. Upon irradiation a decrease in intensity of the asymmetric C - H stretching vibration (va(CH2)) of the isolated cis C = C - H groups (3010 cm-1) was observed. Directly correlated with the decrease of the va(CH2) absorption was a shift of the asymmetric phosphate ester stretching vibration (va(P = O)) towards smaller wavenumbers (1260-->1244 cm-1), indicating that the lipid peroxidation induced molecular alterations in the fatty acid chains influence the packing of the phospholipids in dry multibilayer films. In addition, the formation of a new absorption band at 1693 cm-1 could be detected, the intensity of which was comparable with the formation of thiobarbituric acid reactive substances and, therefore, attributed to the (C = O) stretching of alpha, beta unsaturated aldehydes. Dose-dependent studies using ionizing radiation showed that the decrease of va(CH2) was directly correlated with an increase in absorption of the conjugated dienes at 234 nm and with the formation of hydroperoxides suggesting that the absorption at 3010 cm-1 is solely due to isolated cis C = C - H groups and hence subject to the early stages of the radical chain reaction. UV-C light induced lipid peroxidation revealed a non-linear decrease of I3010, which was directly correlated with the formation of hydroperoxides. The observed early saturation of the conjugated dienes was attributed to an early photodecomposition of the conjugated double bonds.

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

    PubMed

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

    2014-05-01

    Introducción: La radiación ultravioleta tipo C (UV-C) presenta mayor energía y es menos estudiada que la radiación UV-B, debido a que se considera que es totalmente absorbida por la capa de ozono. Sin embargo, la radiación UV-C artificial es capaz de generar diversas modificaciones en las plantas. Dado que la exposición a UV-C por intervalos de tiempo cortos incrementa la concentración de compuestos antioxidantes, mejorando la apariencia y vida de anaquel de los productos, su potencial aplicación en tratamientos poscosecha para modificar el contenido antioxidante de plantas medicinales, como la damiana (Turnera diffusa), es novedoso y relevante. Objetivo: Determinar el efecto de la radiación UV-C sobre las defensas antioxidantes enzimáticas y no enzimáticas, así como en los niveles de daño oxidativo de damiana (Turnera diffusa) in vitro. Resultados: La radiación UV-C disminuyó la actividad de las enzimas superóxido dismutasa (SOD, EC 1.15.1.1) y peroxidasas totales (POX, CE 1.11.1), la concentración de clorofila (a y b), carotenos, vitamina C y la capacidad antioxidante total, e incrementó el contenido de compuestos fenólicos en damiana. La disminución de las defensas antioxidantes fue mayor en plantas de damiana expuestas a dosis más altas de UV-C o por períodos más largos. Estos resultados sugieren que la radiación UV-C induce estrés oxidativo, evidenciado por el incremento del contenido de carbonilos proteicos y el contenido de compuestos fenólicos en damiana (T. diffusa). Conclusión: Dosis bajas y menor exposición a UV-C estimulan la síntesis de compuestos fenólicos en damiana. Por ello, tratamientos controlados con UV-C podrían emplearse como tratamientos poscosecha para incrementar el contenido de compuestos fenólicos en plantas de damiana.

  6. Effects of UV-C treatment and cold storage on ergosterol and vitamin D2 contents in different parts of white and brown mushroom (Agaricus bisporus).

    PubMed

    Guan, Wenqiang; Zhang, Jie; Yan, Ruixiang; Shao, Suqin; Zhou, Ting; Lei, Jing; Wang, Zhidong

    2016-11-01

    Effects of ultraviolet-C (UV-C) treatment (0.5, 1.0 and 2.0kJ/m(2)) and cold storage on ergosterol and vitamin D2 content in different parts of white and brown button mushrooms (Agaricus bisporus) were investigated. UV-C treatment did not significantly affect ergosterol content in the caps and stems of the two mushrooms, but ergosterol content increased significantly during 14days cold storage. Vitamin D2 content in the caps and stems of two mushrooms significantly increased as UV-C dose increased, and 2.0kJ/m(2) UV-C showed the best result. During cold storage, vitamin D2 content in the caps of the two mushrooms decreased from day 1 to day 7, and then kept stable until day 14, but vitamin D2 content in the stems of brown mushrooms kept increasing for the whole 14days period. UV-C could increase vitamin D2 contents in both caps and stems of white and brown mushrooms without significantly affecting ergosterol content.

  7. Listeria monocytogenes survival of UV-C radiation is enhanced by presence of sodium chloride, organic food material and by bacterial biofilm formation.

    PubMed

    Bernbom, N; Vogel, B F; Gram, L

    2011-05-14

    The bactericidal effect on food processing surfaces of ceiling-mounted UV-C light (wavelength 254 nm) was determined in a fish smoke house after the routine cleaning and disinfection procedure. The total aerobic counts were reduced during UV-C light exposure (48 h) and the number of Listeria monocytogenes positive samples went from 30 (of 68) before exposure to 8 (of 68). We therefore in a laboratory model determined the L. monocytogenes reduction kinetics by UV-C light with the purpose of evaluating the influence of food production environmental variables, such as presence of NaCl, organic material and the time L. monocytogenes was allowed to adhere to steel before exposure. L. monocytogenes grown and attached in tryptone soy broth (TSB) with glucose were rapidly killed (after 2 min) by UV-C light. However, bacteria grown and adhered in TSB with glucose and 5% NaCl were more resistant and numbers declined with 4-5 log units during exposure of 8-10 min. Bacteria grown in juice prepared from cold-smoked salmon were protected and numbers were reduced with 2-3 log when UV-C light was used immediately after attachment whereas numbers did not change at all if bacteria had been allowed to form a biofilm for 7 days before exposure. It is not known if this enhanced survival is due to physiological changes in the attached bacterial cells, a physical protection of the cells in the food matrix or a combination. In conclusion, we demonstrate that UV-C light is a useful extra bacteriocidal step and that it, as all disinfecting procedures, is hampered by the presence of organic material.

  8. UV-B and UV-C pre-treatments induce physiological changes and artemisinin biosynthesis in Artemisia annua L. - an antimalarial plant.

    PubMed

    Rai, Rashmi; Meena, Ram Prasad; Smita, Shachi Shuchi; Shukla, Aparna; Rai, Sanjay Kumar; Pandey-Rai, Shashi

    2011-12-02

    Present study was undertaken to investigate if short-term UV-B (4.2 kJ m(-2) day(-1)) and UV-C (5.7 kJ m(-2) day(-1)), pre-treatments can induce artemisinin biosynthesis in Artemisia annua. Twenty-one day old Artemisia seedlings were subjected to short-term (14 days) UV pre-treatment in an environmentally controlled growth chamber and then transplanted to the field under natural conditions. Treatment of A. annua with artificial UV-B and UV-C radiation not only altered the growth responses, biomass, pigment content and antioxidant enzyme activity but enhanced the secondary metabolites (artemisinin and flavonoid) content at all developmental stages as compared to non-irradiated plants. The extent of oxidative damage was measured in terms of the activities of enzymes such as catalase, superoxide dismutase and ascorbate peroxidase. Reinforcement in the antioxidative defense system seems to be a positive response of plants in ameliorating the negative effects of UV-B and UV-C radiations. While the carotenoid content was elevated, the chlorophyll content decreased under UV-B and UV-C pre-treatments. The reverse transcription PCR analysis of the genes associated in artemisinin/isoprenoid biosynthesis like 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), cytochrome P450 oxidoreductase (CPR) and amorpha-4,11-diene synthase (ADS) genes at different growth stages revealed UV induced significant over-expression of the above protein genes. UV-B and UV-C pre-treatments, led to an increase in the concentrations of artemisinin at full bloom stage by 10.5% and 15.7% than that of the control respectively. Thus, the result of our study suggests that short term UV-B pre-treatment of seedlings in greenhouse prior to transplantation into the field enhances artemisinin production with lesser yield related damages as compared to UV-C radiation in A. annua.

  9. Effectiveness of two-sided UV-C treatments in inhibiting natural microflora and extending the shelf-life of minimally processed 'Red Oak Leaf' lettuce.

    PubMed

    Allende, Ana; McEvoy, James L; Luo, Yaguang; Artes, Francisco; Wang, Chien Y

    2006-05-01

    The use of UV-C radiation treatments to inhibit the microbial growth and extend the shelf-life of minimally processed 'Red Oak Leaf' lettuce was investigated. Initially, UV-C resistance of 20 bacterial strains from different genera often associated with fresh produce (Enterobacter, Erwinia, Escherichia, Leuconostoc, Pantoea, Pseudomonas, Rahnela, Salmonella, Serratia and Yersinia) were tested in vitro. Most of the bacterial strains were inhibited with the minimum dose (30 J m(-2)). Erwinia carotovora, Leuconostoc carnosum, Salmonella typhimurium, and Yersinia aldovae were the most resistant strains requiring a UV-C dose of 85 J m(-2) to completely inhibit growth. An in vivo study consisted of treating minimally processed 'Red Oak Leaf' lettuce (Lactuca sativa) with UV-C at three radiation doses (1.18, 2.37 and 7.11 kJ m(-2)) on each side of the leaves and storing the product under passive MAP conditions at 5 degrees C for up to 10 days. The gas composition inside packages varied significantly among the treatments, with CO2 concentrations positively and O2 concentrations negatively correlating with the radiation dose. All the radiation doses were effective in reducing the natural microflora of the product, although the highest doses showed the greatest microbial inhibitions. Taking into account the microbial limit set by Spanish legislation [Boletín Oficial del Estado (BOE), 2001. Normas de higiene para la elaboración, distribución y comercio de comidas preparadas, Madrid, Spain, Real Decreto 3484/2000, pp. 1435-1441], all UV-C treatments extended the shelf-life of the product. However, the 7.11 kJ m(-2) dose induced tissue softening and browning after 7 days of storage at 5 degrees C. Therefore, the use of two sided UV-C radiation, at the proper dose, is effective in reducing the natural microflora and extending the shelf-life of minimally processed 'Red Oak Leaf' lettuce.

  10. Emerging micropollutant oxidation during disinfection processes using UV-C, UV-C/H2O2, UV-A/TiO2 and UV-A/TiO2/H2O2.

    PubMed

    Pablos, Cristina; Marugán, Javier; van Grieken, Rafael; Serrano, Elena

    2013-03-01

    Regeneration of wastewater treatment plant effluents constitutes a solution to increase the availability of water resources in arid regions. Water reuse legislation imposes an exhaustive control of the microbiological quality of water in the operation of disinfection tertiary treatments. Additionally, recent reports have paid increasing attention to emerging micropollutants with potential biological effects even at trace level concentration. This work focuses on the evaluation of several photochemical technologies as disinfection processes with the aim of simultaneously achieving bacterial inactivation and oxidation of pharmaceuticals as examples of emerging micropollutants typically present in water and widely studied in the literature. UV-C-based processes show a high efficiency to inactivate bacteria. However, the bacterial damages are reversible and only when using H(2)O(2), bacterial reproduction is affected. Moreover, a complete elimination of pharmaceutical compounds was not achieved at the end of the inactivation process. In contrast, UV-A/TiO(2) required a longer irradiation time to inactivate bacteria but pharmaceuticals were completely removed along the process. In addition, its oxidation mechanism, based on hydroxyl radicals (OH), leads to irreversible bacterial damages, not requiring of chemicals to avoid bacterial regrowth. For UV-A/TiO(2)/H(2)O(2) process, the addition of H(2)O(2) improved Escherichia coli inactivation since the cell wall weakening, due to OH attacks, allowed H(2)O(2) to diffuse into the bacteria. However, a total elimination of the pharmaceuticals was not achieved during the inactivation process.

  11. Enumeration, isolation, and characterization of ultraviolet (UV-C) resistant bacteria from rock varnish in the Whipple Mountains, California

    NASA Astrophysics Data System (ADS)

    Kuhlman, K. R.; Allenbach, L. B.; Ball, C. L.; Fusco, W. G.; La Duc, M. T.; Kuhlman, G. M.; Anderson, R. C.; Stuecker, T.; Erickson, I. K.; Benardini, J.; Crawford, R. L.

    2005-04-01

    The in situ search for life on Mars requires an understanding of the possible habitats available and the types of microbes that inhabit such environments on Earth. Rock varnish is ubiquitous in terrestrial deserts and has been suggested to exist on Mars. Data reported here show that there are very high numbers of bacteria ( 10-10 g dry wt) associated with rock varnish collected in the hot desert of the Whipple Mountains, south of Death Valley, CA, USA. Some of the bacteria identified in the rock varnish from the Whipple Mountains are resistant to UV-C exposure. This suggests that habitats like rock varnish, if they occur in the martian polar regions where liquid water may be available, may provide niches for radiation-resistant life forms such as the bacteria observed in the Whipple Mountains varnish ecosystem. The UV-resistant microbes isolated represent a diverse group of genera, but all are from the order Actinomycetales (the genera Arthrobacter, Curtobacterium, Geodermatophilus, and Cellulomonas). They are metabolically versatile heterotrophs capable of growing on a variety of simple sugars, amino acids, organic acids and aromatic acids as sole carbon and energy sources.

  12. Fate of E. coli O157:H7, Salmonella spp. and potential surrogate bacteria on apricot fruit following UV-C light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some soft fruit, such as tree-ripened apricots, cannot be washed with aqueous sanitizers, due to their innate softness and delicate surfaces. In this study, ultraviolet-C (UV-C) light was investigated for its efficacy in inactivating 4-5 individual strains of Escherichia coli O157:H7 and Salmonella...

  13. Effect of UV-C treatment on inactivation of Escherichia coli O157:H7, microbial loads, and quality of button mushrooms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effects of ultraviolet-C (UV-C) light applied to both sides of mushrooms on microbial loads and product quality during storage for 21 days at 4 C. Microflora populations, color, antioxidant activity, total phenolics, and ascorbic acid were measured at 1, 7, 14 and 21 days...

  14. Vitamin D2, Ergosterol, and Vitamin B2 Content in Commercially Dried Mushrooms Marketed in China and Increased Vitamin D2 Content Following UV-C Irradiation.

    PubMed

    Huang, Guocheng; Cai, Weixi; Xu, Baojun

    2016-11-21

    Mushrooms are a great source of vitamin D and vitamin B2; however, the content of these vitamins in dried mushrooms has not fully been investigated. Thus, the objectives of this study were to determine the contents of vitamin D2, ergosterol, and vitamin B2 in commercially dried edible mushrooms in China and to investigate the effect of UV-C irradiation on fresh mushrooms. Among the 35 species of dried mushrooms considered for this study, the average ergosterol content was 1.98 mg/g, while the average vitamin D2 content was 16.88 µg/g. The average vitamin B2 content in dried mushrooms was 12.68 µg/g. Fresh shaggy ink caps and oyster mushrooms, when exposed to UV-C at 254 nm at a dose of 0.25 J/cm(2) for 10, 30, and 60 min, showed significantly (p < 0.05) increased vitamin D2 content (229.7 and 67.0 µg/g, respectively) as compared to its fresh counterparts. The conversion of ergosterol to vitamin D2 induced by UV-C irradiation at 0.25 J/cm(2) was significant (p < 0.05). In conclusion, dried commercial mushrooms have higher contents of ergosterol and vitamin D2 than fresh mushrooms. UV-C radiation can be used to increase vitamin D2 content in mushrooms.

  15. Effect of Ultraviolet-A (UV-A) and Ultraviolet-C (UV-C) Light on Mechanical Properties of Oyster Mushrooms during Growth

    PubMed Central

    Edward, Tindibale L.; Kirui, M. S. K.; Omolo, Josiah O.; Ngumbu, Richard G.; Odhiambo, Peter M.

    2014-01-01

    This study investigated the effects of ultraviolet-A (UV-A) and ultraviolet-C (UV-C) light on the mechanical properties in oyster mushrooms during the growth. Experiments were carried out with irradiation of the mushrooms with UV-A (365 nm) and UV-C (254 nm) light during growth. The exposure time ranged from 10 minutes to 60 minutes at intervals of 10 minutes and irradiation was done for three days. The samples for experimental studies were cut into cylindrical shapes of diameter 12.50 mm and thickness 3.00 mm. The storage modulus, loss modulus, and loss factor of the irradiated samples and control samples were determined for both UV bands and there was a significant difference between the storage modulus, loss modulus, and loss factor of the irradiated samples by both UV bands with reference to the control sample, P < 0.05. UV-C light irradiated samples had higher loss modulus and loss factor but low storage modulus as temperature increased from 35 to 100°C with respect to the control sample while UV-A light irradiated samples had lower loss modulus, low loss factor, and higher storage modulus than UV-C irradiated samples. PMID:25580117

  16. Automated UV-C mutagenesis of Kluyveromyces marxianus NRRL Y-1109 and selection for microaerophilic growth and ethanol production at elevated temperature on biomass sugars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The yeast Kluyveromyces marxianus is a potential microbial catalyst for producing ethanol from lignocellulosic substrates at elevated temperatures. To improve its growth and ethanol yield under anaerobic conditions, K. marxianus NRRL Y-1109 was irradiated with UV-C, and surviving cells were grown a...

  17. UV-C mutagenesis of Kluyveromyces marxianus NRRL Y-1109 strain for improved anaerobic growth at elevated temperature on pentose and hexose sugars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More robust industrial yeast strains from Kluyveromyces marxianus NRRL Y-1109 and have been produced using UV-C irradiation specifically for anaerobic conversion of lignocellulosic sugar streams to fuel ethanol at elevated temperature (45°C). This type of random mutagenesis offers the possibility o...

  18. Use of response surface methodology to study the combined effects of UV-C and thermal process on vegetable oxidative enzymes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of ultraviolet processing (UV-C) (temperature, exposure time, and wavelength) and an environmental parameter (pH) were studied on three oxidative enzymes, namely, lipoxygenase (LOX), peroxidase (POD) and polyphenoloxidase (PPO) by using a central composite design. An initial screening de...

  19. Photocatalytic removal of doxycycline from aqueous solution using ZnO nano-particles: a comparison between UV-C and visible light.

    PubMed

    Pourmoslemi, Shabnam; Mohammadi, Ali; Kobarfard, Farzad; Amini, Mohsen

    2016-10-01

    Zinc oxide nano-particles were synthesized, characterized and used for photocatalytic degradation of doxycycline using UV-C and visible light. Effects of several operational factors including initial pH of antibiotic solution, initial antibiotic concentration and ZnO nano-particles loading amount were investigated. Comparing photocatalytic degradation and mineralization of doxycycline under UV-C and visible light showed successful application of the method under both light sources. However, reaction rate was higher under UV-C irradiation, which degraded doxycycline almost completely in 5 hours, and 68% mineralization was achieved. Synthesized ZnO nano-particles were successfully applied for photocatalytic degradation of doxycycline in a pharmaceutical wastewater sample. The process was fitted to the pseudo first order kinetic model with rate constants in the range of 6-22(×10(-3)) mg L(-1) min(-1) with respect to initial concentration of doxycycline under UV-C irradiation. The Langmuir-Hinshelwood model was also employed for describing the photocatalytic reaction with surface reaction kinetic constant kc and equilibrium adsorption constant KLH values calculated as 0.12 mg L(-1) min(-1) and 2.2 L mg(-1), respectively. Degradation of doxycycline was followed by UV-visible spectroscopy and a validated stability indicating high-performance liquid chromatography method that was developed using stressed samples of doxycycline and could selectively determine doxycycline in the presence of its degradation products. Mass spectrometry was used for determining final degradation products.

  20. Fate of E. coli O157:H7, Salmonella spp. and potential surrogate bacteria on apricot fruit, following exposure to UV-C light.

    PubMed

    Yun, Juan; Yan, Ruixiang; Fan, Xuetong; Gurtler, Joshua; Phillips, John

    2013-09-16

    Some soft fruit, such as tree-ripened apricots, cannot be washed with aqueous sanitizers, due to their innate softness and delicate surfaces. In this study, ultraviolet-C (UV-C) light was investigated for its efficacy in inactivating 4-5 individual strains of Escherichia coli O157:H7 and Salmonella spp. on apricots, in addition to a four-strain composite of Shiga toxin-negative E. coli O157:H7 and a cocktail of three attenuated strains of Salmonella Typhimurium and Salmonella Typhimurium LT2. Also, the survival of E. coli O157:H7 and Salmonella spp. after exposure to 74 and 442 mJ/cm² of UV-C was evaluated during post-UV storage at 2 and 20 °C. The fruit was spot inoculated and the areas (ca. 1.5 cm²) of fruit surface with the inoculated bacteria were exposed to UV-C at 7.4 mW/cm². E. coli O157:H7 and Salmonella spp. populations decreased rapidly (1-2 logs) (P<0.05) with increasing UV-C doses of 0 to 74 mJ/cm². Further increases in UV-C dosage achieved only limited additional reductions in bacterial populations. Shiga toxin-negative bacteria and attenuated S. Typhimurium strains, along with S. Typhimurium LT2, responded similarly to corresponding pathogenic E. coli O157:H7 and Salmonella spp. During storage at 2 or 20 °C, populations of pathogenic E. coli O157:H7 and Salmonella spp. on untreated fruit decreased slowly; however, populations on fruit treated with 442 mJ/cm² decreased rapidly at both temperatures. After 8 days at 20 °C or 21 days at 2 °C, E. coli O157:H7 and Salmonella spp. populations on UV-C treated fruit were at least 2 log CFU/g lower than on non-treated controls. Our results suggest that surface-inoculated bacteria survived poorly following UV-C treatment of apricots.

  1. Comparing TiO2 photocatalysis and UV-C radiation for inactivation and mutant formation of Salmonella typhimurium TA102.

    PubMed

    Fiorentino, Antonino; Rizzo, Luigi; Guilloteau, Hélène; Bellanger, Xavier; Merlin, Christophe

    2017-01-01

    Salmonellosis is one of the most common causes of foodborne bacterial human disease worldwide, and the emergence of multidrug-resistant (MDR) strains of Salmonella enterica serovar Typhimurium (S. typhimurium) was associated to the incidence of invasive salmonellosis. The objective of the present work was to investigate the effects of the TiO2 photocatalysis process in terms of both bacteria inactivation and the emergence of mutants, on S. typhimurium TA102 water suspensions. The TiO2 photocatalysis was compared with a conventional disinfection process such as UV-C radiation. In spite of the faster bacterial inactivation obtained in UV-C disinfection experiments (45, 15, and 10 min for total inactivation for initial cell density 10(9), 10(8), and 10(7) CFU mL(-1), respectively), photocatalytic disinfection (60, 30, and 15 min) was more energy efficient because of a lower energy requirement (2-20 mWs cm(-2)) compared to the UV-C disinfection process (5-30 mWs cm(-2)). During the photocatalytic experiments, the mutation frequency increased up to 1648-fold compared to background level for a 10(8) CFU mL(-1) initial bacterial density, and mutants were inactivated after 1-10-min treatment, depending on initial bacterial cell density. In UV-C disinfection experiments, the mutation frequency increased up to 2181-fold for a 10(8) CFU mL(-1) initial bacterial cell density, and UV-C doses in the range of 0.5-4.8 mWs cm(-2) were necessary to decrease mutation frequency. In conclusion, both disinfection processes were effective in the inactivation of S. typhimurium cells, and mutants released into the environment can be avoided if cells are effectively inactivated.

  2. Disinfection of water and wastewater by UV-A and UV-C irradiation: application of real-time PCR method.

    PubMed

    Chatzisymeon, Efthalia; Droumpali, Ariadni; Mantzavinos, Dionissios; Venieri, Danae

    2011-03-02

    The disinfection efficiency of synthetic and real wastewater by means of UV-A and UV-C irradiation in the presence or absence of TiO(2) was investigated. A reference strain of Escherichia coli suspended in sterile 0.8% (w/v) NaCl aqueous solution was used as a synthetic wastewater, while real wastewater samples were collected from the outlet of the secondary treatment of a municipal wastewater treatment plant. E. coli inactivation was monitored both by the conventional culture technique and by the real-time PCR method. Culture method showed that UV-C irradiation (11 W lamp) achieved total E. coli inactivation of 100% within 3 min of photolytic treatment. On the other hand, UV-A (9 W lamp)/TiO(2); [TiO(2)]=200 mg L(-1) (i.e. best operating conditions) required 60 min to achieve total disinfection of the synthetic wastewater. Real time PCR revealed compatible results, regarding the better efficiency of UV-C. However, it showed different times of bacterial inactivation, probably due to the phenomenon of "viable but not culturable bacteria". Disinfection durability tests in the dark and under natural sunlight irradiation showed that there is cell repair when UV-C irradiation is used for synthetic wastewater disinfection. Regarding real wastewater it was observed that only UV-C irradiation was capable of totally inactivating E. coli population in short time. Comparing results obtained from both methods, real time PCR proved to be more reliable and accurate, concerning the bacterial detection and enumeration in aquatic samples after the application of UV irradiation.

  3. Increased ethanol production with UV-C mutagenized Kluyveromyces marxianus capable of anaerobic growth at elevated temperature on pentose and hexose sugars using fermentation strategies with corn pericarp hydrolysates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several novel Kluyveromyces marxianus strains were obtained by irradiation with UV-C (UV-C 234nm) to achieve an 80% mortality rate. The surviving cells were subsequently grown anaerobically for 5 months at 46C and resulted in two mutagenized strains that were able to grow anaerobically at elevated ...

  4. Effect of germicidal UV-C light(254 nm) on eggs and adult of house dustmites, Dermatophagoides pteronyssinus and Dermatophagoides farinae (Astigmata: Pyroglyhidae)

    PubMed Central

    Lah, Ernieenor Faraliana Che; Musa, Raja Noor Azreen Raja; Ming, Ho Tze

    2012-01-01

    Objective To examined the immediate and 24 hours post- irradiation germicidal effects of UV-C lamp on eggs and adults of house dust mites Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae). Methods This study investigated the immediate and 24 hours post irradiation mortalities of adult mites exposed to UV-C at different exposure times (5 mins, 10 mins, 15 mins, 20 mins, 30 mins and 60 mins) and distances (10 cm, 25 cm, 35 cm, 45 cm and 55 cm). Fresh eggs of the 2 dust mites were also irradiated at 10, 35 and 55 cm for 0.5, 1, 2, 3, and 5 minutes, and observed daily post- irradiation for up to 7 days. Results Highest immediate mortality of 100% occurred with direct irradiation at 10 cm distance from UV-C lamp and for 60 mins, for both species of mites. The post 24 hours mean mortality rates were (58.4±17.4)% for D. pteronyssinus and (27.7±9.7)% for D. farinae when irradiated for 1 hour at 55 cm distance under UV-C lamp. When mites were irradiated in the presence of culture media, the highest mortality rates were lower compared to the direct irradiation; at 10 cm distance and 60 mins exposure, the mean mortality was (74.0±6.8)% for D. pteronyssinus and (70.3±6.7)% for D. farinae. Egg hatchability for both species of mites was also notably reduced by greater than 50% following irradiation. Conclusions Ultraviolet C irradiation is lethal to an array of organisms by damaging their nucleic acids (DNA and RNA). This study demonstrates the increasing mite mortalities with increasing exposure times and decreasing distances. PMID:23569994

  5. Effect of postharvest UV-C treatment on the bacterial diversity of Ataulfo mangoes by PCR-DGGE, survival of E. coli and antimicrobial activity.

    PubMed

    Fernández-Suárez, Rocío; Ramírez-Villatoro, Guadalupe; Díaz-Ruiz, Gloria; Eslava, Carlos; Calderón, Montserrat; Navarro-Ocaña, Arturo; Trejo-Márquez, Andrea; Wacher, Carmen

    2013-01-01

    Since Mexico is the second largest exporter of mangoes, its safety assurance is essential. Research in microbial ecology and knowledge of complex interactions among microbes must be better understood to achieve maximal control of pathogens. Therefore, we investigated the effect of UV-C treatments on bacterial diversity of the Ataulfo mangoes surface using PCR-DGGE analysis of variable region V3 of 16S rRNA genes, and the survival of E. coli, by plate counting. The UV-C irradiation reduced the microbial load on the surface of mangoes immediately after treatment and the structure of bacterial communities was modified during storage. We identified the key members of the bacterial communities on the surface of fruits, predominating Enterobacter genus. Genera as Lactococcus and Pantoea were only detected on the surface of non-treated (control) mangoes. This could indicate that these genera were affected by the UV-C treatment. On the other hand, the treatment did not have a significant effect on survival of E. coli. However, genera that have been recognized as antagonists against foodborne pathogens were identified in the bands patterns. Also, phenolic compounds were determined by HPLC and antimicrobial activity was assayed according to the agar diffusion method. The main phenolic compounds were chlorogenic, gallic, and caffeic acids. Mango peel methanol extracts (UV-C treated and control mangoes) showed antimicrobial activity against strains previously isolated from mango, detecting significant differences (P < 0.05) among treated and control mangoes after 4 and 12 days of storage. Ps. fluorescens and Ps. stutszeri were the most sensitive.

  6. Effect of postharvest UV-C treatment on the bacterial diversity of Ataulfo mangoes by PCR-DGGE, survival of E. coli and antimicrobial activity

    PubMed Central

    Fernández-Suárez, Rocío; Ramírez-Villatoro, Guadalupe; Díaz-Ruiz, Gloria; Eslava, Carlos; Calderón, Montserrat; Navarro-Ocaña, Arturo; Trejo-Márquez, Andrea; Wacher, Carmen

    2013-01-01

    Since Mexico is the second largest exporter of mangoes, its safety assurance is essential. Research in microbial ecology and knowledge of complex interactions among microbes must be better understood to achieve maximal control of pathogens. Therefore, we investigated the effect of UV-C treatments on bacterial diversity of the Ataulfo mangoes surface using PCR-DGGE analysis of variable region V3 of 16S rRNA genes, and the survival of E. coli, by plate counting. The UV-C irradiation reduced the microbial load on the surface of mangoes immediately after treatment and the structure of bacterial communities was modified during storage. We identified the key members of the bacterial communities on the surface of fruits, predominating Enterobacter genus. Genera as Lactococcus and Pantoea were only detected on the surface of non-treated (control) mangoes. This could indicate that these genera were affected by the UV-C treatment. On the other hand, the treatment did not have a significant effect on survival of E. coli. However, genera that have been recognized as antagonists against foodborne pathogens were identified in the bands patterns. Also, phenolic compounds were determined by HPLC and antimicrobial activity was assayed according to the agar diffusion method. The main phenolic compounds were chlorogenic, gallic, and caffeic acids. Mango peel methanol extracts (UV-C treated and control mangoes) showed antimicrobial activity against strains previously isolated from mango, detecting significant differences (P < 0.05) among treated and control mangoes after 4 and 12 days of storage. Ps. fluorescens and Ps. stutszeri were the most sensitive. PMID:23761788

  7. Survival and growth of Cronobacter sakazakii on fresh-cut fruit and the effect of UV-C illumination and electrolyzed water in the reduction of its population.

    PubMed

    Santo, David; Graça, Ana; Nunes, Carla; Quintas, Célia

    2016-08-16

    Cronobacter sakazakii, found in foods such as powdered infant formula and plant origin ready-to-eat food, is an opportunistic pathogen to infants, neonates and vulnerable adults. The objective of this study was to monitor the growth of C. sakazakii in fresh-cut 'Royal gala' apple, 'Rocha' pear, and 'Piel de sapo' melon, and the effect of UV-C illumination, acidic electrolyzed water (AEW) and neutral electrolyzed water (NEW) in the reduction of its population. Fresh-cut fruits were inoculated and incubated at different temperatures during 10days while monitoring C. sakazakii. The inhibitory activity of different doses of UV-C (0-10kJ.m(2)), electrolyzed water and sodium hypochlorite (SH) (100ppm chlorine) was evaluated on the fruits inoculated with C. sakazakii. The bacterium showed a significant growth in the fruits at 12 and 20°C, but did not grow at 4°C, despite having survived for 10days. At 8°C, adaptation phases of 0.6-3.9days were estimated in the fruits before exponential growth. The UV-C 7.5 and 10kJ/m(2) produced greater C. sakazakii population decreases (2-2.4logcfu/g) than AEW (1.3-1.8logcfu/g), NEW (1-1.2logcfu/g) and SH (0.8-1.4logcfu/g). The UV-C decontamination system and refrigeration at 4°C, may contribute to the product's safety and quality. The results help better understand the behavior of C. sakazakii on fresh-cut fruit alerting producers of the necessity to respect the high hygienic practices, adequate refrigerating temperature maintenance and caution with the tendency to prolong the validity of this kind of ready-to-eat food.

  8. Welding of silver nanowire networks via flash white light and UV-C irradiation for highly conductive and reliable transparent electrodes

    NASA Astrophysics Data System (ADS)

    Chung, Wan-Ho; Kim, Sang-Ho; Kim, Hak-Sung

    2016-08-01

    In this work, silver nanowire inks with hydroxypropyl methylcellulose (HPMC) binders were coated on polyethylene terephthalate (PET) substrates and welded via flash white light and ultraviolet C (UV-C) irradiation to produce highly conductive transparent electrodes. The coated silver nanowire films were firmly welded and embedded into PET substrate successfully at room temperature and under ambient conditions using an in-house flash white light welding system and UV-C irradiation. The effects of light irradiation conditions (light energy, irradiation time, pulse duration, and pulse number) on the silver nanowire networks were studied and optimized. Bending fatigue tests were also conducted to characterize the reliability of the welded transparent conductive silver nanowire films. The surfaces of the welded silver nanowire films were analyzed via scanning electron microscopy (SEM), while the transmittance of the structures was measured using a spectrophotometer. From the results, a highly conductive and transparent silver nanowire film with excellent reliability could be achieved at room temperature under ambient conditions via the combined flash white light and UV-C irradiation welding process.

  9. Postharvest stilbenes and flavonoids enrichment of table grape cv Redglobe (Vitis vinifera L.) as affected by interactive UV-C exposure and storage conditions.

    PubMed

    Crupi, Pasquale; Pichierri, Arianna; Basile, Teodora; Antonacci, Donato

    2013-11-15

    Flavonoids and stilbenes are secondary metabolites produced in plants that can play an important health-promoting role. The biosynthesis of these compounds generally increases as a response to biotic or abiotic stress; therefore, in order to achieve as high phenolic accumulation as possible, the interactive effects of storage conditions (temperature and time) and UV-C radiation on polyphenols content in postharvest Redglobe table grape variety were investigated. During a storage time longer than 48h, both cold storage (4°C) and UV-C exposure of almost 3min (2.4kJm(-2)) positively enhanced the content of cis- and trans-piceid (34 and 90μgg(-1) of skin, respectively) together with quercetin-3-O-galactoside and quercetin-3-O-glucoside (15 and 140μgg(-1) of skin, respectively) up to three fold respect to control grape samples. Conversely, catechin was not significantly affected by irradiation and storage treatments. With regard anthocyanins, the highest concentrations of cyanidin-3-O-glucoside and peonidin-3-Oglucoside were observed in Redglobe, stored at both room temperature and 4°C, after 5min (4.1kJm(-2)) of UV-C treatment and 24h of storage. Gathered findings showed that combined postharvest treatments can lead to possible "functional" grapes, within normal conditions of market commercialization, responding to the rising consumers demand to have foods that support and promote health.

  10. Welding of silver nanowire networks via flash white light and UV-C irradiation for highly conductive and reliable transparent electrodes

    PubMed Central

    Chung, Wan-Ho; Kim, Sang-Ho; Kim, Hak-Sung

    2016-01-01

    In this work, silver nanowire inks with hydroxypropyl methylcellulose (HPMC) binders were coated on polyethylene terephthalate (PET) substrates and welded via flash white light and ultraviolet C (UV-C) irradiation to produce highly conductive transparent electrodes. The coated silver nanowire films were firmly welded and embedded into PET substrate successfully at room temperature and under ambient conditions using an in-house flash white light welding system and UV-C irradiation. The effects of light irradiation conditions (light energy, irradiation time, pulse duration, and pulse number) on the silver nanowire networks were studied and optimized. Bending fatigue tests were also conducted to characterize the reliability of the welded transparent conductive silver nanowire films. The surfaces of the welded silver nanowire films were analyzed via scanning electron microscopy (SEM), while the transmittance of the structures was measured using a spectrophotometer. From the results, a highly conductive and transparent silver nanowire film with excellent reliability could be achieved at room temperature under ambient conditions via the combined flash white light and UV-C irradiation welding process. PMID:27553755

  11. A Model For Selecting An Environmentally Responsive Trait: Evaluating Micro-scale Fitness Through UV-C Resistance and Exposure in Escherichia coli.

    NASA Astrophysics Data System (ADS)

    Schenone, D. J.; Igama, S.; Marash-Whitman, D.; Sloan, C.; Okansinski, A.; Moffet, A.; Grace, J. M.; Gentry, D.

    2015-12-01

    Experimental evolution of microorganisms in controlled microenvironments serves as a powerful tool for understanding the relationship between micro-scale microbial interactions as well as local-to global-scale environmental factors. In response to iterative and targeted environmental pressures, mutagenesis drives the emergence of novel phenotypes. Current methods to induce expression of these phenotypes require repetitive and time intensive procedures and do not allow for the continuous monitoring of conditions such as optical density, pH and temperature. To address this shortcoming, an Automated Dynamic Directed Evolution Chamber is being developed. It will initially produce Escherichia coli cells with an elevated UV-C resistance phenotype that will ultimately be adapted for different organisms as well as studying environmental effects. A useful phenotype and environmental factor for examining this relationship is UV-C resistance and exposure. In order to build a baseline for the device's operational parameters, a UV-C assay was performed on six E. coli replicates with three exposure fluxes across seven iterations. The fluxes included a 0 second exposure (control), 6 seconds at 3.3 J/m2/s and 40 seconds at 0.5 J/m2/s. After each iteration the cells were regrown and tested for UV-C resistance. We sought to quantify the increase and variability of UV-C resistance among different fluxes, and observe changes in each replicate at each iteration in terms of variance. Under different fluxes, we observed that the 0s control showed no significant increase in resistance, while the 6s/40s fluxes showed increased resistance as the number of iterations increased. A one-million fold increase in survivability was observed after seven iterations. Through statistical analysis using Spearman's rank correlation, the 40s exposure showed signs of more consistently increased resistance, but seven iterations was insufficient to demonstrate statistical significance; to test this further

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

    PubMed

    Songsamoe, Sumethee; Matan, Narumol; Matan, Nirundorn

    2016-03-01

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

  13. Erythromycin oxidation and ERY-resistant Escherichia coli inactivation in urban wastewater by sulfate radical-based oxidation process under UV-C irradiation.

    PubMed

    Michael-Kordatou, I; Iacovou, M; Frontistis, Z; Hapeshi, E; Dionysiou, D D; Fatta-Kassinos, D

    2015-11-15

    This study evaluates the feasibility of UV-C-driven advanced oxidation process induced by sulfate radicals SO4(.)- in degrading erythromycin (ERY) in secondary treated wastewater. The results revealed that 10 mg L(-1) of sodium persulfate (SPS) can result in rapid and complete antibiotic degradation within 90 min of irradiation, while ERY decay exhibited a pseudo-first-order kinetics pattern under the different experimental conditions applied. ERY degradation rate was strongly affected by the chemical composition of the aqueous matrix and it decreased in the order of: ultrapure water (kapp = 0.55 min(-1)) > bottled water (kapp = 0.26 min(-1)) > humic acid solution (kapp = 0.05 min(-1)) > wastewater effluents (kapp = 0.03 min(-1)). Inherent pH conditions (i.e. pH 8) yielded an increased ERY degradation rate, compared to that observed at pH 3 and 5. The contribution of hydroxyl and sulfate radicals (HO. and SO4(.)-) on ERY degradation was found to be ca. 37% and 63%, respectively. Seven transformation products (TPs) were tentatively elucidated during ERY oxidation, with the 14-membered lactone ring of the ERY molecule being intact in all cases. The observed phytotoxicity against the tested plant species can potentially be attributed to the dissolved effluent organic matter (dEfOM) present in wastewater effluents and its associated-oxidation products and not to the TPs generated from the oxidation of ERY. This study evidences the potential use of the UV-C/SPS process in producing a final treated effluent with lower phytotoxicity (<10%) compared to the untreated wastewater. Finally, under the optimum experimental conditions, the UV-C/SPS process resulted in total inactivation of ERY-resistant Escherichia coli within 90 min.

  14. Photoreactivation and dark repair of environmental E. coli strains following 24 kHz continuous ultrasound and UV-C irradiation.

    PubMed

    Kaur, Jasjeet; Karthikeyan, Raghupathy; Pillai, Suresh D

    2016-07-02

    In this study, effects of 24 kHz continuous ultrasound and UV-C on inactivation and potential repair of environmental E. coli strains were studied through a culture based method and a metabolic activity assay. Three environmental E. coli strains isolated from fecal samples of feral hog and deer and treated wastewater effluent were studied and compared with a laboratory E. coli strain (ATCC® 10798). Metabolic activity of E. coli cells during the inactivation and repair period was assessed using the AlamarBlue® assay. Transmission electron microscopy assays were also performed to evaluate morphological damage of bacterial cell wall. After 24 h of photoreactivation period, laboratory E. coli strain (ATCC® 10798) reactivated by 30% and 42% in contrast to E. coli isolate from treated wastewater effluent, which reactivated by 53% and 82% after ultrasound and UV-C treatment, respectively. Possible shearing and reduction in cell size of E. coli strains exposed to ultrasound was revealed by transmission electron micrographs. Metabolic activity of E. coli strains was greatly reduced due to morphological damage to cell membrane caused by 24 kHz continuous ultrasound. Based upon experimental data and TEM micrographs, it could be concluded that ultrasound irradiation has potential in advanced water treatment and water reuse applications.

  15. Expression and In Situ Localization of Two Major PR Proteins of Grapevine Berries during Development and after UV-C Exposition

    PubMed Central

    Colas, Steven; Afoufa-Bastien, Damien; Jacquens, Lucile; Clément, Christophe; Baillieul, Fabienne

    2012-01-01

    In grapevine Vitis vinifera L. cv Pinot noir, the Pathogenesis-Related (PR) proteins CHI4D and TL3 are among the most abundant extractable PR proteins of ripe berries and accumulate during berry ripening from véraison until full maturation. Evidence was supplied in favor of the involvement of these two protein families in plant defense mechanisms and plant development. In order to better understand CHI4D and TL3 function in grapevine, we analyzed their temporal and spatial pattern of expression during maturation and after an abiotic stress (UV-C) by in situ hybridization (ISH) and immunohistolocalization. In ripening berries, CHI4D and TL3 genes were mainly expressed in the exocarp and around vascular bundles of the mesocarp. In UV-C exposed berries, CHI4D and TL3 gene expression was strongly induced before véraison. Corresponding proteins localized in the exocarp and, to a lesser extent, around vascular bundles of the mesocarp. The spatial and temporal accumulation of the two PR proteins during berry maturation and after an abiotic stress is discussed in relation to their putative roles in plant defense. PMID:22937077

  16. Heritage materials and biofouling mitigation through UV-C irradiation in show caves: state-of-the-art practices and future challenges.

    PubMed

    Borderie, Fabien; Alaoui-Sossé, Badr; Aleya, Lotfi

    2015-03-01

    Biofouling, i.e., colonization of a given substrate by living organisms, has frequently been reported for heritage materials and particularly on stone surfaces such as building facades, historical monuments, and artworks. This also concerns subterranean environments such as show caves, in which the installation of artificial light for tourism has led to the proliferation of phototrophic microorganisms. In Europe nowadays, the use of chemicals in these very sensitive environments is scrutinized and regulated by the European Union. New and environmentally friendly processes must be developed as alternative methods for cave conservation. For several years, the UV irradiation currently used in medical facilities and for the treatment of drinking water has been studied as a new innovative method for the conservation of heritage materials. This paper first presents a review of the biofouling phenomena on stone materials such as building facades and historical monuments. The biological disturbances induced by tourist activity in show caves are then examined, with special attention given to the methods and means to combat them. Thirdly, a general overview is given of the effects of UV-C on living organisms, and especially on photosynthetic microorganisms, through different contexts and studies. Finally, the authors' own experiments and findings are presented concerning the study and use of UV-C irradiation to combat algal proliferation in show caves. Both laboratory and in situ results are summarized and synthesized from their previously published works. The application of UV in caves is discussed and further experiments are proposed to enhance research in this domain.

  17. Multivariate analysis of anionic, cationic and nonionic textile surfactant degradation with the H(2)O(2)/UV-C process by using the capabilities of response surface methodology.

    PubMed

    Olmez-Hanci, Tugba; Arslan-Alaton, Idil; Basar, Gulcan

    2011-01-15

    Anionic, cationic and nonionic surfactants being frequently employed in the textile preparation process were subjected to H(2)O(2)/UV-C treatment. As a consequence of the considerable number of parameters affecting the H(2)O(2)/UV-C process, an experimental design methodology was used to mathematically describe and optimize the single and combined influences of the critical process variables treatment time, initial H(2)O(2)concentration and chemical oxygen demand (COD) on parent pollutant (surfactant) as well as organic carbon (COD and total organic carbon (TOC)) removal efficiencies. Multivariate analysis was based on two different photochemical treatment targets; (i) full oxidation/complete treatment of the surfactants or, alternatively, (ii) partial oxidation/pretreatment of the surfactants to comply with the legislative discharge requirements. According to the established polynomial regression models, the process independent variables "treatment time" (exerting a positive effect) and "initial COD content" (exerting a negative effect) played more significant roles in surfactant photodegradation than the process variable "initial H(2)O(2) concentration" under the studied experimental conditions.

  18. Efficacy of UV-C irradiation for inactivation of food-borne pathogens on sliced cheese packaged with different types and thicknesses of plastic films.

    PubMed

    Ha, Jae-Won; Back, Kyeong-Hwan; Kim, Yoon-Hee; Kang, Dong-Hyun

    2016-08-01

    In this study, the efficacy of using UV-C light to inactivate sliced cheese inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and, packaged with 0.07 mm films of polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene (PP), and polyethylene (PE) was investigated. The results show that compared with PET and PVC, PP and PE films showed significantly reduced levels of the three pathogens compared to inoculated but non-treated controls. Therefore, PP and PE films of different thicknesses (0.07 mm, 0.10 mm, and 0.13 mm) were then evaluated for pathogen reduction of inoculated sliced cheese samples. Compared with 0.10 and 0.13 mm, 0.07 mm thick PP and PE films did not show statistically significant reductions compared to non-packaged treated samples. Moreover, there were no statistically significant differences between the efficacy of PP and PE films. These results suggest that adjusted PP or PE film packaging in conjunction with UV-C radiation can be applied to control foodborne pathogens in the dairy industry.

  19. Distribution of resveratrol and stilbene synthase in young grape plants (Vitis vinifera L. cv. Cabernet Sauvignon) and the effect of UV-C on its accumulation.

    PubMed

    Wang, Wei; Tang, Ke; Yang, Hao-Ru; Wen, Peng-Fei; Zhang, Ping; Wang, Hui-Ling; Huang, Wei-Dong

    2010-01-01

    Current research indicated that the resveratrol was mainly accumulated in the skin of grape berry, however, little is yet known about the distribution of resveratrol, as well as the regulation mechanism at protein level and the localization of stilbene synthase (malonyl-CoA:4-coumaroyl-CoA malonyltransferase; EC 2.3.1.95; STS), a key enzyme of resveratrol biosynthesis, in young grape plants (Vitis vinifera L. cv. Cabernet Sauvignon). Resveratrol, whose constitutive level ranged from 0.2 mg kg(-1) FW to 16.5 mg kg(-1) FW, could be detected in stem, axillary bud, shoot tip, petiole, root and leaf of grape plants. Among them, stem phloems presented the most abundant of resveratrol, and the leaves presented the lowest. Interestingly, the level of STS mRNA and protein were highest in grape leaves. And the analysis of immunohistochemical showed the tissue-specific distribution of STS in different organs, presenting the similar results compared with the amount of protein. And the subcellular localization revealed that the cell wall in different tissues processed the most golden particles representing STS. Subjecting to UV-C irradiation, resveratrol and STS were both intensely stimulated in grape leaves, with the similar response pattern. Results above indicated that distribution of resveratrol and STS in grape was organ-specific and tissue-specific. And the accumulation of resveratrol induced by UV-C was regulated by transcriptional and translational level of STS.

  20. Role of ozone in UV-C disinfection, demonstrated by comparison between wild-type and mutant conidia of Aspergillus niger.

    PubMed

    Liu, Jing; Zhou, Lin; Chen, Ji-Hong; Mao, Wang; Li, Wen-Jian; Hu, Wei; Wang, Shu-Yang; Wang, Chun-Ming

    2014-01-01

    This study aimed to investigate the tolerance of a melanized wild-type strain of Aspergillus niger (CON1) and its light-colored mutant (MUT1) to UV-C light and the concomitantly generated ozone. Treatments were segregated into four groups based on whether UV irradiation was used and the presence or absence of ozone: (-UV, -O3), (-UV, +O3), (+UV, -O3) and (+UV, +O3). The survival of CON1 and MUT1 conidia under +UV decreased as the exposure time increased, with CON1 showing greater resistance to UV irradiation than MUT1. Ozone induced CON1 conidium inactivation only under conditions of UV radiation exposure. While, the inactivation effect of ozone on MUT1 was always detectable regardless of the presence of UV irradiation. Furthermore, the CON1 conidial suspension showed lower UV light transmission than MUT1 when examined at the same concentration. Compared with the pigment in MUT1, the melanin in CON1 exhibited more potent radical-scavenging activity and stronger UV absorbance. These results suggested that melanin protected A. niger against UV disinfection via UV screening and free radical scavenging. The process by which UV-C disinfection induces a continual decrease in conidial survival suggests that UV irradiation and ozone exert a synergistic fungicidal effect on A. niger prior to reaching a plateau.

  1. Irradiation with UV-C inhibits TNF-α-dependent activation of the NF-κB pathway in a mechanism potentially mediated by reactive oxygen species.

    PubMed

    Szoltysek, Katarzyna; Walaszczyk, Anna; Janus, Patryk; Kimmel, Marek; Widlak, Piotr

    2017-01-01

    Pathways depending on the NF-κB transcription factor are essential components of cellular response to stress. Plethora of stimuli modulating NF-κB includes inflammatory signals, ultraviolet radiation (UV) and reactive oxygen species (ROS), yet interference between different factors affecting NF-κB remains relatively understudied. Here, we aim to characterize the influence of UV radiation on TNF-α-induced activity of the NF-κB pathway. We document inhibition of TNF-α-induced activation of NF-κB and subsequent suppression of NF-κB-regulated genes in cells exposed to UV-C several hours before TNF-α stimulation. Accumulation of ROS and subsequent activation of NRF2, p53, AP-1 and NF-κB-dependent pathways, with downstream activation of antioxidant mechanisms (e.g., SOD2 and HMOX1 expression), is observed in the UV-treated cells. Moreover, NF-κB inhibition is not observed if generation of UV-induced ROS is suppressed by chemical antioxidants. It is noteworthy that stimulation with TNF-α also generates a wave of ROS, which is suppressed in cells pre-treated by UV. We postulate that irradiation with UV-C activates antioxidant mechanisms, which in turn affect ROS-mediated activation of NF-κB by TNF-α. Considering a potential cross talk between p53 and NF-κB, we additionally compare observed effects in p53-proficient and p53-deficient cells and find the UV-mediated suppression of TNF-α-activated NF-κB in both types of cells.

  2. Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions.

    PubMed

    Bhuvaneshwari, M; Iswarya, V; Archanaa, S; Madhu, G M; Kumar, G K Suraish; Nagarajan, R; Chandrasekaran, N; Mukherjee, Amitava

    2015-05-01

    Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5±2.55 nm for ZnO-1 NPs and 616.2±38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn(2+) ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses.

  3. Resistance of the genome of Escherichia coli and Listeria monocytogenes to irradiation evaluated by the induction of cyclobutane pyrimidine dimers and 6-4 photoproducts using gamma and UV-C radiations

    NASA Astrophysics Data System (ADS)

    Beauchamp, S.; Lacroix, M.

    2012-08-01

    The effect of gamma and UV-C irradiation on the production of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4 PPs) in DNA was investigated to compare the natural resistance of the genome of a Gram-positive bacterium and a Gram-negative bacterium against irradiation. Solution of pure DNA and bacterial strains Listeria monocytogenes and Escherichia coli were irradiated using gamma and UV-C rays. Extracted DNA from bacteria and pure DNA samples were then analysed by ELISA using anti-CPDs and anti-6-4 PPs monoclonal antibodies. The results show that gamma rays, as well as UV-C rays, induce the formation of CPDs and 6-4 PPs in DNA. During UV-C irradiation, the three samples showed a difference in their sensitivity against formation of CPDs (P≤0.05). Pure DNA was the most sensitive while the genome of L. monocytogenes was the most resistant. Also during UV-C irradiation, the genome of L. monocytogenes was the only one to show a significant resistance against formation of 6-4 PPs (P≤0.05). During gamma irradiation, for both types of lesion, pure DNA and the genome of E. coli did not show significant difference in their sensitivity (P>0.05) while the genome of L. monocytogenes showed a resistance against formation of CPDs and 6-4 PPs.

  4. Pulsed UV-C disinfection of Escherichia coli with light-emitting diodes, emitted at various repetition rates and duty cycles.

    PubMed

    Wengraitis, Stephen; McCubbin, Patrick; Wade, Mary Margaret; Biggs, Tracey D; Hall, Shane; Williams, Leslie I; Zulich, Alan W

    2013-01-01

    A 2010 study exposed Staphylococcus aureus to ultraviolet (UV) radiation and thermal heating from pulsed xenon flash lamps. The results suggested that disinfection could be caused not only by photochemical changes from UV radiation, but also by photophysical stress damage caused by the disturbance from incoming pulses. The study called for more research in this area. The recent advances in light-emitting diode (LED) technology include the development of LEDs that emit in narrow bands in the ultraviolet-C (UV-C) range (100-280 nm), which is highly effective for UV disinfection of organisms. Further, LEDs would use less power, and allow more flexibility than other sources of UV energy in that the user may select various pulse repetition frequencies (PRFs), pulse irradiances, pulse widths, duty cycles and types of waveform output (e.g. square waves, sine waves, triangular waves, etc.). Our study exposed Escherichia coli samples to square pulses of 272 nm radiation at various PRFs and duty cycles. A statistically significant correlation was found between E. coli's disinfection sensitivity and these parameters. Although our sample size was small, these results show promise and are worthy of further investigation. Comparisons are also made with pulsed disinfection by LEDs emitting at 365 nm, and pulsed disinfection by xenon flash lamps.

  5. Evaluation of UV-C induced changes in Escherichia coli DNA using repetitive extragenic palindromic-polymerase chain reaction (REP-PCR).

    PubMed

    Trombert, Alejandro; Irazoqui, Horacio; Martín, Carlos; Zalazar, Fabián

    2007-11-12

    Ultraviolet radiation is an efficient inactivation method for a broad range of bacteria, viruses and parasites. Inactivation of microorganisms by UV-B and UV-C radiation is driven through modifications in their genomic DNA, being the most stable DNA-lesions different kinds of pyrimidine dimers (PDs) (e.g., cyclobutane pyrimidine dimers (CPDs) and other photoproducts). Taking into account that these modifications inhibit the DNA polymerization in vivo as well as in vitro, in the present work the usefulness of the REP-PCR assay to detect UV-induced changes in the Escherichia coli DNA was evaluated. In vitro amplification of DNA extracted at different times after UV treatment showed a disappearance of amplicons of higher size as time of treatment increases. When the bacteria were let to progress through their dark repair process, modifications in the electrophoretic patterns by REP-PCR were observed again. Amplified bacterial DNA tended to recover the profile showed at the beginning of treatment. In addition, the reappearance of bands of higher molecular size was associated to an increase in their signal intensity probably due to a higher amplification rate. Results of REP-PCR were correlated to the colony-forming ability of E. coli. It was concluded that REP-PCR appears as a rapid, robust, useful complementary methodology to monitor the impact of UV irradiation--at a molecular level--on the inactivation and the mechanisms of repair, applicable on a broad spectrum of microorganisms.

  6. Effects of UV-C treatment on inactivation of Salmonella and Escherichia coli O157:H7 on tomato surface and steam scars, native microbial loads, and quality of grape tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effectiveness of ultraviolet-C (UV-C) light inactivation as affected by the location of pathogens on the smooth surface and at stem scars of Grape tomatoes. A bacterial cocktail containing three strains of E. coli O157:H7 (C9490, E02128 and F00475) and a three serotypes o...

  7. UV-C tolerance of symbiotic Trebouxia sp. in the space-tested lichen species Rhizocarpon geographicum and Circinaria gyrosa: role of the hydration state and cortex/screening substances

    NASA Astrophysics Data System (ADS)

    Sánchez, Francisco Javier; Meeßen, Joachim; del Carmen Ruiz, M.; Sancho, Leopoldo G.; Ott, Sieglinde; Vílchez, Carlos; Horneck, Gerda; Sadowsky, Andres; de la Torre, Rosa

    2014-01-01

    Many experiments were carried out in order to evaluate the survival capacity of extremotolerant lichens when facing harsh conditions, including those of outer space or of simulated Martian environment. For further progress, a deeper study on the physiological mechanisms is needed that confer the unexpected levels of resistance detected on these symbiotic organisms. In this work, the response of the lichenized green algae Trebouxia sp. (a predominant lichen photobiont) to increasing doses of UV-C radiation is studied. UV-C (one of the most lethal factors to be found in space together with vacuum and cosmic-ionizing radiation with high atomic number and energy (HZE) particles) has been applied in the present experiments up to a maximum dose analogue to 67 days in Low Earth Orbit (LEO). For that purpose we selected two extremotolerant and space-tested lichen species in which Trebouxia sp. is the photosynthetic partner: the crustose lichen Rhizocarpon geographicum and the fruticose lichen Circinaria gyrosa. In order to evaluate the effect of the physiological state of the lichen thallus (active when wet and dormant when dry) and of protective structures (cortex and photoprotective pigments) on the resistance of the photobiont to UV-C, four different experimental conditions were tested: (1) dry intact samples, (2) wet intact samples, (3) dry samples without cortex/acetone-rinsed and (4) wet samples without cortex/acetone-rinsed. After irradiation and a 72 hours period of recovery, the influence of UV-C on the two lichen's photobiont under each experimental approach was assessed by two complimentary methods: (1) By determining the photosystem II (PSII) activity in three successive 24 hours intervals (Mini-PAM fluorometer) to investigate the overall state of the photosynthetic process and the resilience of Trebouxia sp. (2) By performing high performance liquid chromatography (HPLC)-quantification of four essential photosynthetic pigments (chlorophyll a, chlorophyll b,

  8. Intelligent, Energy Saving Power Supply and Control System of Hoisting Mine Machine with Compact and Hybrid Drive System / Inteligentne, Energooszczędne Układy Zasilania I Sterowania Górniczych Maszyn Wyciągowych Z Napędem Zintegrowanym Lub Hybrydowym

    NASA Astrophysics Data System (ADS)

    Szymański, Zygmunt

    2015-03-01

    lub tyrystorowego) zasilacza przekształtnikowego, oraz inteligentnego obwodu sterowania zbudowanego na wielopoziomowych sterownikach mikroprocesorowych. Przedstawiono analizę możliwości zastosowania wybranych metod sztucznej inteligencji w układach sterowania, automatyki oraz diagnostyki maszyn wyciągowych. W referacie ograniczono się do analizy metod sterowania rozmytego, metod algorytmów genetycznych oraz nowoczesnych sieci neuronowych II oraz III generacji. Metody te zapewniają realizację złożonych algorytmów sterowania maszyną wyciągową z zapewnieniem energooszczędnych warunków eksploatacyjnych, monitoringu parametrów eksploatacyjnych oraz predykcyjną diagnostykę stanu technicznego maszyny wyciągowej, minimalizującą liczbę stanów awaryjnych. Przedstawiono koncepcję układu sterowania i diagnostyki maszyny bazującej na metodzie: fuzzy-logic neuro set control system (sterowanie rozmyte w sieciach neuronowych). Przedstawiono wybrane algorytmy sterowania oraz wyniki analiz komputerowych wybranych modeli matematycznych maszyny wyciągowej. Wyniki rozważań teoretycznych zostały częściowo sprawdzone w warunkach laboratoryjnych oraz przemysłowych.

  9. Materials Data on LuB2Ru (SG:62) by Materials Project

    SciTech Connect

    Kristin Persson

    2016-02-10

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  10. Environmental and biological factors influencing the UV-C resistance of Listeria monocytogenes.

    PubMed

    Gayán, E; Serrano, M J; Pagán, R; Álvarez, I; Condón, S

    2015-04-01

    In this investigation, the effect of microbiological factors (strain, growth phase, exposition to sublethal stresses, and photorepair ability), treatment medium characteristics (pH, water activity, and absorption coefficient), and processing parameters (dose and temperature) on the UV resistance of Listeria monocytogenes was studied. The dose to inactivate 99.99% of the initial population of the five strains tested ranged from 21.84 J/mL (STCC 5672) to 14.66 J/mL (STCC 4031). The UV inactivation of the most resistant strain did not change in different growth phases and after exposure to sublethal heat, acid, basic, and oxidative shocks. The pH and water activity of the treatment medium did not affect the UV resistance of L. monocytogenes, whereas the inactivation rate decreased exponentially with the absorption coefficient. The lethal effect of UV radiation increased synergistically with temperature between 50 and 60 °C (UV-H treatment). A UV-H treatment of 27.10 J/mL at 55 °C reached 2.99 and 3.69 Log10 inactivation cycles of L. monocytogenes in orange juice and vegetable broth, and more than 5 Log10 cycles in apple juice and chicken broth. This synergistic effect opens the possibility to design UV combined processes for the pasteurization of liquid foods with high absorptivity.

  11. Sterilization effect of 254 nm UV-C irradiation against cynaobacteria Microcystis aeruginosa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harmful algal bloom (HAB) produced by several cyanobacterial species is a significant threat to many aquatic ecosystems around the world. Recently frequent occurrence of serious algal bloom in Lake Taihu, Lake Dianchi, and Lake Chaohu has become a serious concern in China. Although various methods a...

  12. Mechanism of the synergistic inactivation of Escherichia coli by UV-C light at mild temperatures.

    PubMed

    Gayán, E; Mañas, P; Álvarez, I; Condón, S

    2013-07-01

    UV light only penetrates liquid food surfaces to a very short depth, thereby limiting its industrial application in food pasteurization. One promising alternative is the combination of UV light with mild heat (UV-H), which has been demonstrated to produce a synergistic bactericidal effect. The aim of this article is to elucidate the mechanism of synergistic cellular inactivation resulting from the simultaneous application of UV light and heat. The lethality of UV-H treatments remained constant below ∼45°C, while lethality increased exponentially as the temperature increased. The percentage of synergism reached a maximum (40.3%) at 55°C. Neither the flow regimen nor changes in the dose delivered by UV lamps contributed to the observed synergism. UV-H inactivation curves of the parental Escherichia coli strain obtained in a caffeic acid selective recovery medium followed a similar profile to those obtained with uvrA mutant cells in a nonselective medium. Thermal fluidification of membranes and synergistic lethal effects started around 40 to 45°C. Chemical membrane fluidification with benzyl alcohol decreased the UV resistance of the parental strain but not that of the uvrA mutant. These results suggest that the synergistic lethal effect of UV-H treatments is due to the inhibition of DNA excision repair resulting from the membrane fluidification caused by simultaneous heating.

  13. Inactivation of Salmonella enterica by UV-C light alone and in combination with mild temperatures.

    PubMed

    Gayán, E; Serrano, M J; Raso, J; Alvarez, I; Condón, S

    2012-12-01

    The aim of this investigation was to study the efficacy of the combined processes of UV light and mild temperatures for the inactivation of Salmonella enterica subsp. enterica and to explore the mechanism of inactivation. The doses to inactivate the 99.99% (4D) of the initial population ranged from 18.03 (Salmonella enterica serovar Typhimurium STCC 878) to 12.75 J ml(-1) (Salmonella enterica serovar Enteritidis ATCC 13076). The pH and water activity of the treatment medium did not change the UV tolerance, but it decreased exponentially by increasing the absorption coefficient. An inactivating synergistic effect was observed by applying simultaneous UV light and heat treatment (UV-H). A less synergistic effect was observed by applying UV light first and heat subsequently. UV did not damage cell envelopes, but the number of injured cells was higher after a UV-H treatment than after heating. The synergistic effect observed by combining simultaneous UV and heat treatment opens the possibility to design combined treatments for pasteurization of liquid food with high UV absorptivity, such as fruit juices.

  14. Inactivation of avirulent pgm+ and delta pgm Yersinia pestis by ultraviolet light (UV-C)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yersinia pestis is the causative agent of bubonic plague. Though not considered a foodborne pathogen, Y. pestis can survive, and even grow, in some foods, and the foodborne route of transmission is not without precedent. As such, concerns exist over the possible intentional contamination of foods wi...

  15. Hg speciation by differential photochemical vapor generation at UV-B and UV-C wavelengths

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mercury speciation was accomplished by differential photochemical reduction at two UV wavelengths; the resulting Hg(O) vapor was quantified by atomic fluorescence spectrometry. After microwave digestion and centrifugation, analyte solutions were mixed with 20% (v/v) formic acid in a reactor coil, an...

  16. Decontamination Efficiency of a DBD Lamp Containing an UV-C Emitting Phosphor.

    PubMed

    Caillier, Bruno; Caiut, José Maurício Almeida; Muja, Cristina; Demoucron, Julien; Mauricot, Robert; Dexpert-Ghys, Jeanette; Guillot, Philippe

    2015-01-01

    Among different physical and chemical agents, the UV radiation appears to be an important route for inactivation of resistant microorganisms. The present study introduces a new mercury-free Dielectric Barrier Discharge (DBD) flat lamp, where the biocide action comes from the UV emission produced by rare-earth phosphor obtained by spray pyrolysis, following plasma excitation. In this study, the emission intensity of the prototype lamp is tuned by controlling gas pressure and electrical power, 500 mbar and 15 W, corresponding to optimal conditions. In order to characterize the prototype lamp, the energetic output, temperature increase following lamp ignition and ozone production of the source were measured. The bactericidal experiments carried out showed excellent results for several gram-positive and gram-negative bacterial strains, thus demonstrating the high decontamination efficiency of the DBD flat lamp. Finally, the study of the external morphology of the microorganisms after the exposure to the UV emission suggested that other mechanisms than the bacterial DNA damage could be involved in the inactivation process.

  17. Mechanism of the Synergistic Inactivation of Escherichia coli by UV-C Light at Mild Temperatures

    PubMed Central

    Gayán, E.; Mañas, P.; Álvarez, I.

    2013-01-01

    UV light only penetrates liquid food surfaces to a very short depth, thereby limiting its industrial application in food pasteurization. One promising alternative is the combination of UV light with mild heat (UV-H), which has been demonstrated to produce a synergistic bactericidal effect. The aim of this article is to elucidate the mechanism of synergistic cellular inactivation resulting from the simultaneous application of UV light and heat. The lethality of UV-H treatments remained constant below ∼45°C, while lethality increased exponentially as the temperature increased. The percentage of synergism reached a maximum (40.3%) at 55°C. Neither the flow regimen nor changes in the dose delivered by UV lamps contributed to the observed synergism. UV-H inactivation curves of the parental Escherichia coli strain obtained in a caffeic acid selective recovery medium followed a similar profile to those obtained with uvrA mutant cells in a nonselective medium. Thermal fluidification of membranes and synergistic lethal effects started around 40 to 45°C. Chemical membrane fluidification with benzyl alcohol decreased the UV resistance of the parental strain but not that of the uvrA mutant. These results suggest that the synergistic lethal effect of UV-H treatments is due to the inhibition of DNA excision repair resulting from the membrane fluidification caused by simultaneous heating. PMID:23686270

  18. Effects of integrated treatment of nonthermal UV-C light and different antimicrobial wash on Salmonella enterica on plum tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Produce contamination by foodborne pathogens remains a serious threat. This study investigated synergistic effects of ultraviolet-C and various active sanitizers’ washes against Salmonella enterica on plum tomatoes. A bacterial cocktail containing three serotypes of Salmonella enterica (S. Newport H...

  19. Fabrication and structural properties of AlN submicron periodic lateral polar structures and waveguides for UV-C applications

    NASA Astrophysics Data System (ADS)

    Alden, D.; Guo, W.; Kirste, R.; Kaess, F.; Bryan, I.; Troha, T.; Bagal, A.; Reddy, P.; Hernandez-Balderrama, Luis H.; Franke, A.; Mita, S.; Chang, C.-H.; Hoffmann, A.; Zgonik, M.; Collazo, R.; Sitar, Z.

    2016-06-01

    Periodically poled AlN thin films with submicron domain widths were fabricated for nonlinear applications in the UV-VIS region. A procedure utilizing metalorganic chemical vapor deposition growth of AlN in combination with laser interference lithography was developed for making a nanoscale lateral polarity structure (LPS) with domain size down to 600 nm. The Al-polar and N-polar domains were identified by wet etching the periodic LPS in a potassium hydroxide solution and subsequent scanning electron microscopy (SEM) characterization. Fully coalesced and well-defined vertical interfaces between the adjacent domains were established by cross-sectional SEM. AlN LPSs were mechanically polished and surface roughness with a root mean square value of ˜10 nm over a 90 μm × 90 μm area was achieved. 3.8 μm wide and 650 nm thick AlN LPS waveguides were fabricated. The achieved domain sizes, surface roughness, and waveguides are suitable for second harmonic generation in the UVC spectrum.

  20. Effect of exposure to UV-C irradiation and monochloramine on adenovirus serotype 2 early protein expression and DNA replication.

    PubMed

    Sirikanchana, Kwanrawee; Shisler, Joanna L; Mariñas, Benito J

    2008-06-01

    The mechanisms of adenovirus serotype 2 inactivation with either UV light (with a narrow emission spectrum centered at 254 nm) or monochloramine were investigated by assessing the potential inhibition of two key steps of the adenovirus life cycle, namely, E1A protein synthesis and viral genomic replication. E1A early protein synthesis was assayed by using immunoblotting, while the replication of viral DNA was analyzed by using slot blotting. Disinfection experiments were performed in phosphate buffer solutions at pH 8 and room temperature (UV) or 20 degrees C (monochloramine). Experimental results revealed that normalized E1A levels at 12 h postinfection (p.i.) were statistically the same as the corresponding decrease in survival ratio for both UV and monochloramine disinfection. Normalized DNA levels at 24 h p.i. were also found to be statistically the same as the corresponding decrease in survival ratio for monochloramine disinfection. In contrast, for UV disinfection, genomic DNA levels were much lower than E1A or survival ratios, possibly as a result of a delay in DNA replication for UV-treated virions compared to that for controls. Future efforts will determine the pre-E1A synthesis step in the adenovirus life cycle affected by exposure to UV and monochloramine, with the goal of identifying the viral molecular target of these two disinfectants.

  1. 157 nm Pellicles (Thin Films) for Photolithography: Mechanistic Investigation of the VUV and UV-C Photolysis of Fluorocarbons

    SciTech Connect

    Lee, Kwangjoo; Jockusch, Steffen; Turro, Nicholas J.; French, Roger H.; Wheland, Robert C.; Lemon, M F.; Braun, Andre M.; Widerschpan, Tatjana; Dixon, David A.; Li, Jun; Ivan, Marius; Zimmerman, Paul

    2005-06-15

    The use of 157 nm as the next lower wavelength for photolithography for the production of semiconductors has created a need for transparent and radiation-durable polymers for use in soft pellicles, the polymer films which protect the chip from particle deposition. The most promising materials for pellicles are fluorinated polymers, but currently available fluorinated polymers undergo photodegradation and/or photodarkening upon long term exposure to 157 nm irradiation. To understand the mechanism of the photodegradation and photodarkening of fluorinated polymers, mechanistic studies on the photolysis of liquid model fluorocarbons, including perfluorobutylethyl ether and perfluoro-2 H-3-oxa-heptane, were performed employing UV, NMR, FTIR, GC, and GC/MS analyses. All hydrogen-containing compounds showed decreased photostability compared to the fully perfluorinated compounds. Irradiation in the presence of atmospheric oxygen showed reduced photostability compared to deoxygenated samples. Photolysis of the samples was performed at 157, 172, 185, and 254 nm and showed only minor wavelength dependence. Mechanisms for photodegradation of the fluorocarbons are proposed, which involve Rydberg excited states. Time-dependent density functional theory has been used to predict the excitation spectra of model compounds.

  2. UV-C irradiation of HSV-1 infected fibroblasts (HSV-FS) enhances human natural killer (NK) cell activity against these targets

    SciTech Connect

    Pettera, L.; Fitzgerald-Bocarsly, P. )

    1991-03-11

    Expression of Herpes Simplex Virus Type 1 (HSV-1) immediate early gene products has been bound to be sufficient for NK cell mediated lysis of HSV-1 infected FS. To block the targets at various stages in the infectious cycle, HSV-FS were irradiated with UV light for 1 min at 2, 6, and 20 hr post-infection. NK mediated lysis of 2 hr and 5 hr UV treated HSV-FS was 2-fold higher than non-UV treated HSV-FS despite a {gt}99% inhibition in virus yield. In contrast, 20 hr infected targets were lysed less well than 2 and 6 hr targets despite strong glycoprotein expression and induction of high levels of interferon-alpha (IFN-{alpha}) production by effector PBMC's; this lysis was not enhanced by UV treatment. Since NK lysis of HSV-FS has been found to be dependent on an HLA-DR{sup +} accessory cell (AC), lysis of irradiated HSV-FS by PBMC's depleted of AC was measured. Such depletion eradicated NK lysis of the UV treated HSV-FS indicating that irradiation does not overcome the AC requirement for NK lysis. UV irradiation of another HLA-DR{sup +} dependent target, Vesicular Stomatitis Virus (VSV) infected FS led to a dramatic reduction in both NK lysis and IFN-{alpha} induction. HSV-1 is a DNA virus whose genes are expressed in a cascade fashion whereas VSV is an RNA virus. The authors hypothesize that the enhancement in AC dependent NK activity observed for UV irradiated HSV-FS, but not VSV-FS, targets is due to overproduction of either a cellular or viral gene product which specifically occurs early in the HSV-1 infectious cycle and is downregulated by 20 hr post-infection.

  3. Effects of UV-C and Vacuum-UV TiO2 Advanced Oxidation Processes on the Acute Mortality of Microalgae.

    PubMed

    McGivney, Eric; Carlsson, Magnus; Gustafsson, Jon Petter; Gorokhova, Elena

    2015-01-01

    Advanced oxidation processes/technologies (AOT) that combine a semiconductor, such as titanium dioxide (TiO2 ), with a UV source have been used to eliminate microorganisms in various water treatment applications. To facilitate the applicability of this technique, the gain in efficiency from the semiconductor compared to the UV source alone with respect to different target organisms requires evaluation. The primary objective of this study was to determine the effects of TiO2 and UV wavelength on a freshwater alga, Pseudokirchneriella subcapitata and a marine alga, Tetraselmis suecica. For each species, dose-response experiments were conducted to determine the median lethal dose (LC50 ) of the following treatments: UV light emitted with a peak of 254 nm, UV light emitted with a peak of 254 nm in the presence of TiO2 and UV light emitted with a peak of 254 and 185 nm in the presence of TiO2 . In both species, the presence of TiO2 significantly increased mortality. Across all three treatments, P. subcapitata was more sensitive than T. suecica; moreover, the addition of the 185 nm wavelength significantly increased cell mortality in P. subcapitata but not in T. suecica.

  4. Nijmegen breakage syndrome (NBS)

    PubMed Central

    2012-01-01

    both alleles of the NBN gene are known. No specific therapy is available for NBS, however, hematopoietic stem cell transplantation may be one option for some patients. Prognosis is generally poor due to the extremely high rate of malignancies. Zespół Nijmegen (Nijmegen breakage syndrome; NBS) jest rzadkim schorzeniem z wrodzoną niestabilnością chromosomową dziedziczącym się w sposób autosomalny recesywny, charakteryzującym się przede wszystkim wrodzonym małogłowiem, złożonymi niedoborami odporności i predyspozycją do rozwoju nowotworów. Choroba występuje najczęściej w populacjach słowiańskich, w których uwarunkowana jest mutacją założycielską w genie NBN (c.657_661del5). Do najważniejszych objawów zespołu zalicza się: małogłowie obecne od urodzenia i postępujące z wiekiem, charakterystyczne cechy dysmorfii twarzy, opóźnienie wzrastania, niepełnosprawność intelektualną w stopniu lekkim do umiarkowanego oraz hipogonadyzm hipogonadotropowy u dziewcząt. Na obraz choroby składają się także: niedobór odporności komórkowej i humoralnej, który jest przyczyną nawracających infekcji, znaczna predyspozycja do rozwoju nowotworów złośliwych (zwłaszcza układu chłonnego), a także zwiększona wrażliwość na promieniowanie jonizujące. Wyniki badań laboratoryjnych wykazują: (1) spontaniczną łamliwość chromosomów w limfocytach T krwi obwodowej, z preferencją do rearanżacji chromosomów 7 i 14, (2) nadwrażliwość na promieniowanie jonizujące lub radiomimetyki, co można wykazać metodami in vitro, (3) radiooporność syntezy DNA, (4) hipomorficzne mutacje na obu allelach genu NBN, oraz (5) brak w komórkach pełnej cząsteczki białka, nibryny. Małogłowie i niedobór odporności występują także w zespole niedoboru ligazy IV (LIG4) oraz w zespole niedoboru NHEJ1. Rodzice powinni otrzymać poradę genetyczną ze względu na wysokie ryzyko (25%) powtórzenia się choroby u kolejnego potomstwa. Możliwe jest

  5. Enhanced inactivation of food-borne pathogens in ready-to-eat sliced ham by near-infrared heating combined with UV-C irradiation and mechanism of the synergistic bactericidal action.

    PubMed

    Ha, Jae-Won; Kang, Dong-Hyun

    2015-01-01

    The objective of the study described in this article was, first, to investigate the effect of the simultaneous application of near-infrared (NIR) heating and UV irradiation on inactivation of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in ready-to-eat (RTE) sliced ham and as well as its effect on product quality and, second, to elucidate the underlying mechanisms of the synergistic bactericidal action of NIR heating and UV irradiation. With the inoculation amounts used, simultaneous NIR-UV combined treatment for 70 s achieved 3.62, 4.17, and 3.43 log CFU reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. For all three pathogens, the simultaneous application of both technologies resulted in an additional log unit reduction as a result of their synergism compared to the sum of the reductions obtained after the individual treatments. To investigate the mechanisms of NIR-UV synergistic injury for a particular microorganism in a food base, we evaluated the effect of four types of metabolic inhibitors using the overlay method and confirmed that damage to cellular membranes and the inability of cells to repair these structures due to ribosomal damage were the primary factors related to the synergistic lethal effect. Additionally, NIR-UV combined treatment for a maximum of 70 s did not alter the color values or texture parameters of ham slices significantly (P > 0.05). These results suggest that a NIR-UV combined process could be an innovative antimicrobial intervention for RTE meat products.

  6. Structure and Property Changes in Self-Assembled Lubricin Layers Induced by Calcium Ion Interactions.

    PubMed

    Greene, George W; Thapa, Rajiv; Holt, Stephen A; Wang, Xiaoen; Garvey, Christopher J; Tabor, Rico F

    2017-03-14

    Lubricin (LUB) is a "mucin-like" glycoprotein found in synovial fluids and coating the cartilage surfaces of articular joints, which is now generally accepted as one of the body's primary boundary lubricants and antiadhesive agents. LUB's superior lubrication and antiadhesion are believed to derive from its unique interfacial properties by which LUB molecules adhere to surfaces (and biomolecules, such as hyaluronic acid and collagen) through discrete interactions localized to its two terminal end domains. These regionally specific interactions lead to self-assembly behavior and the formation of a well-ordered "telechelic" polymer brush structure on most substrates. Despite its importance to biological lubrication, detailed knowledge on the LUB's self-assembled brush structure is insufficient and derived mostly from indirect and circumstantial evidence. Neutron reflectometry (NR) was used to directly probe the self-assembled LUB layers, confirming the polymer brush architecture and resolving the degree of hydration and level of surface coverage. While attempting to improve the LUB contrast in the NR measurements, the LUB layers were exposed to a 20 mM solution of CaCl2, which resulted in a significant change in the polymer brush structural parameters consisting of a partial denaturation of the surface-binding end-domain regions, partial dehydration of the internal mucin-domain "loop", and collapse of the outer mucin-domain surface region. A series of atomic force microscopy measurements investigating the LUB layer surface morphology, mechanical properties, and adhesion forces in phosphate-buffered saline and CaCl2 solutions reveal that the structural changes induced by calcium ion interactions also significantly alter key properties, which may have implications to LUB's efficacy as a boundary lubricant and wear protector in the presence of elevated calcium ion concentrations.

  7. Genetics Home Reference: Snyder-Robinson syndrome

    MedlinePlus

    ... Accardi J, Adams DR, Schwartz CE, Norris J, Wood T, Gafni RI, Collins MT, Tosi LL, Markello ... PubMed Central Cason AL, Ikeguchi Y, Skinner C, Wood TC, Holden KR, Lubs HA, Martinez F, Simensen ...

  8. Sensitivity of pathogenic and attenuated E. coli O157:H7 strains to ultraviolet-C light as assessed by conventional plating methods and ethidium monoazide-PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the UV-C sensitivity of six pathogenic E. coli O157:H7 strains associated with recent outbreaks of foodborne illnesses and four attenuated E. coli O157:H7 strains was investigated. Futhermore, the mechanism of UV-C impact on two pathogenic E. coli strains with different UV-C sensitiv...

  9. Rab2A is a pivotal switch protein that promotes either secretion or ER-associated degradation of (pro)insulin in insulin-secreting cells

    PubMed Central

    Sugawara, Taichi; Kano, Fumi; Murata, Masayuki

    2014-01-01

    Rab2A, a small GTPase localizing to the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC), regulates COPI-dependent vesicular transport from the ERGIC. Rab2A knockdown inhibited glucose-stimulated insulin secretion and concomitantly enlarged the ERGIC in insulin-secreting cells. Large aggregates of polyubiquitinated proinsulin accumulated in the cytoplasmic vicinity of a unique large spheroidal ERGIC, designated the LUb-ERGIC. Well-known components of ER-associated degradation (ERAD) also accumulated at the LUb-ERGIC, creating a suitable site for ERAD-mediated protein quality control. Moreover, chronically high glucose levels, which induced the enlargement of the LUb-ERGIC and ubiquitinated protein aggregates, impaired Rab2A activity by promoting dissociation from its effector, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in response to poly (ADP-ribosyl)ation of GAPDH. The inactivation of Rab2A relieved glucose-induced ER stress and inhibited ER stress-induced apoptosis. Collectively, these results suggest that Rab2A is a pivotal switch that controls whether insulin should be secreted or degraded at the LUb-ERGIC and Rab2A inactivation ensures alleviation of ER stress and cell survival under chronic glucotoxicity. PMID:25377857

  10. A Comparison between Ultraviolet Disinfection and Copper Alginate Beads within a Vortex Bioreactor for the Deactivation of Bacteria in Simulated Waste Streams with High Levels of Colour, Humic Acid and Suspended Solids

    PubMed Central

    Thomas, Simon F.; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel M.; Mason, Paul T.; Allen, Michael J.

    2014-01-01

    We show in this study that the combination of a swirl flow reactor and an antimicrobial agent (in this case copper alginate beads) is a promising technique for the remediation of contaminated water in waste streams recalcitrant to UV-C treatment. This is demonstrated by comparing the viability of both common and UV-C resistant organisms in operating conditions where UV-C proves ineffective - notably high levels of solids and compounds which deflect UV-C. The swirl flow reactor is easy to construct from commonly available plumbing parts and may prove a versatile and powerful tool in waste water treatment in developing countries. PMID:25541706

  11. A comparison between ultraviolet disinfection and copper alginate beads within a vortex bioreactor for the deactivation of bacteria in simulated waste streams with high levels of colour, humic acid and suspended solids.

    PubMed

    Thomas, Simon F; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel M; Mason, Paul T; Allen, Michael J

    2014-01-01

    We show in this study that the combination of a swirl flow reactor and an antimicrobial agent (in this case copper alginate beads) is a promising technique for the remediation of contaminated water in waste streams recalcitrant to UV-C treatment. This is demonstrated by comparing the viability of both common and UV-C resistant organisms in operating conditions where UV-C proves ineffective - notably high levels of solids and compounds which deflect UV-C. The swirl flow reactor is easy to construct from commonly available plumbing parts and may prove a versatile and powerful tool in waste water treatment in developing countries.

  12. On the Sandage period shift effect among field RR Lyrae stars

    NASA Technical Reports Server (NTRS)

    Lee, Young-Wook

    1990-01-01

    The origin of the disagreement between the results of the synthetic horizontal branch (HB) model of Lee et al. (1990) and the Sandage (1990) analysis of Lub's (1977) data on a sample of field RR Lyrae stars is investigated, extending the original synthetic HB calculations of Lee et al. to all HB types over the metallicity range of the Galactic halo. It is shown that the period shifts of the RR Lyrae stars in globular clusters depend strongly on their HB type and metallicity. Results suggest that the disagreement between the slopes, Delta logP(Teff)/Delta Fe/H, obtained by Lee et al. and the ones obtained by Sandage can be explained by the fact that Lub's sample may have contained many highly evolved stars in the metallicity range of Fe/H between -2.0 and -1.6, since Lee's analysis did not include these stars.

  13. On the Sandage period shift effect among field RR Lyrae stars

    SciTech Connect

    Lee, Y. Victoria Univ. )

    1990-11-01

    The origin of the disagreement between the results of the synthetic horizontal branch (HB) model of Lee et al. (1990) and the Sandage (1990) analysis of Lub's (1977) data on a sample of field RR Lyrae stars is investigated, extending the original synthetic HB calculations of Lee et al. to all HB types over the metallicity range of the Galactic halo. It is shown that the period shifts of the RR Lyrae stars in globular clusters depend strongly on their HB type and metallicity. Results suggest that the disagreement between the slopes, Delta logP(Teff)/Delta Fe/H, obtained by Lee et al. and the ones obtained by Sandage can be explained by the fact that Lub's sample may have contained many highly evolved stars in the metallicity range of Fe/H between -2.0 and -1.6, since Lee's analysis did not include these stars. 48 refs.

  14. On Implicit Active Constraints in Linear Semi-Infinite Programs with Unbounded Coefficients

    SciTech Connect

    Goberna, M. A.; Lancho, G. A.; Todorov, M. I.; Vera de Serio, V. N.

    2011-04-15

    The concept of implicit active constraints at a given point provides useful local information about the solution set of linear semi-infinite systems and about the optimal set in linear semi-infinite programming provided the set of gradient vectors of the constraints is bounded, commonly under the additional assumption that there exists some strong Slater point. This paper shows that the mentioned global boundedness condition can be replaced by a weaker local condition (LUB) based on locally active constraints (active in a ball of small radius whose center is some nominal point), providing geometric information about the solution set and Karush-Kuhn-Tucker type conditions for the optimal solution to be strongly unique. The maintaining of the latter property under sufficiently small perturbations of all the data is also analyzed, giving a characterization of its stability with respect to these perturbations in terms of the strong Slater condition, the so-called Extended-Nuernberger condition, and the LUB condition.

  15. Legionella Metaeffector Exploits Host Proteasome to Temporally Regulate Cognate Effector

    PubMed Central

    Kubori, Tomoko; Shinzawa, Naoaki; Kanuka, Hirotaka; Nagai, Hiroki

    2010-01-01

    Pathogen-associated secretion systems translocate numerous effector proteins into eukaryotic host cells to coordinate cellular processes important for infection. Spatiotemporal regulation is therefore important for modulating distinct activities of effectors at different stages of infection. Here we provide the first evidence of “metaeffector,” a designation for an effector protein that regulates the function of another effector within the host cell. Legionella LubX protein functions as an E3 ubiquitin ligase that hijacks the host proteasome to specifically target the bacterial effector protein SidH for degradation. Delayed delivery of LubX to the host cytoplasm leads to the shutdown of SidH within the host cells at later stages of infection. This demonstrates a sophisticated level of coevolution between eukaryotic cells and L. pneumophila involving an effector that functions as a key regulator to temporally coordinate the function of a cognate effector protein. PMID:21151961

  16. High-frequency ultrasound in carpal tunnel syndrome: assessment of patient eligibility for surgical treatment.

    PubMed

    Kapuścińska, Katarzyna; Urbanik, Andrzej

    2015-09-01

    Zespół kanału nadgarstka (ZKN) jest najczęstszą neuropatią uciskową i częstą przyczyną zwolnień lekarskich z powodu przeciążenia ręki związanego z pracą. Optymalne postępowanie w tym zespole zależy od wczesnego rozpoznania i podjęcia odpowiedniego leczenia (zachowawczego lub operacyjnego).

  17. Adaptive mechanically controlled lubrication mechanism found in articular joints.

    PubMed

    Greene, George W; Banquy, Xavier; Lee, Dong Woog; Lowrey, Daniel D; Yu, Jing; Israelachvili, Jacob N

    2011-03-29

    Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple "modes" of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an "adaptive" role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) "boundary lubricant"--reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions.

  18. New nanotechnology solid lubricants for superior dry lubrication

    NASA Astrophysics Data System (ADS)

    Fleischer, N.; Genut, M.; Rapoport, L.; Tenne, R.

    2003-09-01

    This paper presents a new commercial breakthrough for advanced anti-friction materials based on unique inorganic nanospheres that can be used as dry lubricants, coatings, and for impregnating parts. The new material reduces friction and wear significantly better than other layered solid lubricants and is especially useful in self-lubricating, maintenance-free, and oil-free applications of the types encountered in aerospace markets. The material, NanoLubTM, is the world's first commercial lubricant based on spherical inorganic nanoparticles. NanoLub's particles have a unique structure of hollow nested spheres of about only 0.1 micron in diameter. This paper presents tribological evaluations of tungsten and molybdenum disulphide NanoLubTM. The material reduces friction and wear under conditions that are especially relevant for space such as ultra-high vacuum, UV radiation, and high loads. Suitable applications could include rotors, bearings, robots, planetary rovers, space vehicles and transport devices. Extensive testing by a number of independent groups clearly shows that these special nanoparticles improve considerably the tribological properties of different contact pairs in comparison to other solid lubricants.

  19. Ultraviolet-C light inactivation of Penicillium expansum on fruit surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  20. UV-induced fragmentation of Cajal bodies.

    PubMed

    Cioce, Mario; Boulon, Séverine; Matera, A Gregory; Lamond, Angus I

    2006-11-06

    The morphology and composition of subnuclear organelles, such as Cajal bodies (CBs), nucleoli, and other nuclear bodies, is dynamic and can change in response to a variety of cell stimuli, including stress. We show that UV-C irradiation disrupts CBs and alters the distribution of a specific subset of CB components. The effect of UV-C on CBs differs from previously reported effects of transcription inhibitors. We demonstrate that the mechanism underlying the response of CBs to UV-C is mediated, at least in part, by PA28gamma (proteasome activator subunit gamma). The presence of PA28gamma in coilin-containing complexes is increased by UV-C. Overexpression of PA28gamma, in the absence of UV-C treatment, provokes a similar redistribution of the same subset of CB components that respond to UV-C. RNA interference-mediated knockdown of PA28gamma attenuates the nuclear disruption caused by UV-C. These data demonstrate that CBs are specific nuclear targets of cellular stress-response pathways and identify PA28gamma as a novel regulator of CB integrity.

  1. Impact of ultraviolet radiation treatments on the quality of freshly prepared tomato (Solanum lycopersicum) juice.

    PubMed

    Bhat, Rajeev

    2016-12-15

    Impact of ultraviolet (UV-C) radiation treatments (0, 15, 30 and 60min) on freshly extracted tomato juice quality (physicochemical properties, antioxidant activity and microbial load) was evaluated. On exposure to UV-C, level of water activity, total soluble solids, and titratable acidity exhibited non-significant increase up to 30min of exposure time. Regarding colour analysis, L∗ value significantly increased with subsequent decrease in a∗ and b∗ values post UV-C treatments. Clarity, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and total phenolics content significantly increased, whereas ascorbic acid level significantly reduced at 60min of UV-C exposure time. So also, lycopene content exhibited a non-significant decrease after UV-C treatment. Microbial studies showed reduction in total plate count and total mould counts post UV-C treatment. Overall, UV-C treatment being a physical, non-thermal method of food preservation holds the ability to improve or preserve vital quality parameters in freshly prepared tomato juices, and henceforth possesses high scope for commercial exploration.

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

    PubMed

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

    2011-05-01

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

  3. Insights into the Mechanisms Underlying Ultraviolet-C Induced Resveratrol Metabolism in Grapevine (V. amurensis Rupr.) cv. “Tonghua-3”

    PubMed Central

    Yin, Xiangjing; Singer, Stacy D.; Qiao, Hengbo; Liu, Yajun; Jiao, Chen; Wang, Hao; Li, Zhi; Fei, Zhangjun; Wang, Yuejin; Fan, Chonghui; Wang, Xiping

    2016-01-01

    Stilbene compounds belong to a family of secondary metabolites that are derived from the phenylpropanoid pathway. Production of the stilbene phytoalexin, resveratrol, in grape (Vitis spp.) berries is known to be induced by ultraviolet-C radiation (UV-C), which has numerous regulatory effects on plant physiology. While previous studies have described changes in gene expression caused by UV-C light in several plant species, such information has yet to be reported for grapevine. We investigated both the resveratrol content and gene expression responses of berries from V. amurensis cv. Tonghua-3 following UV-C treatment, to accelerate research into resveratrol metabolism. Comparative RNA-Seq profiling of UV-C treated and untreated grape berries resulted in the identification of a large number of differentially expressed genes. Gene ontology (GO) term classification and biochemical pathway analyses suggested that UV-C treatment caused changes in various cellular processes, as well as in both hormone and secondary metabolism. The data further indicate that UV-C induced increases in resveratrol may be related to the transcriptional regulation of genes involved in the production of secondary metabolites and signaling, as well as several transcription factors. We also observed that following UV-C treatment, 22 stilbene synthase (STS) genes exhibited increases in their expression levels and a VaSTS promoter drove the expression of the GUS reporter gene when expressed in tobacco. We therefore propose that UV-C induction of VaSTS expression is an important factor in promoting resveratrol accumulation. This transcriptome data set provides new insight into the response of grape berries to UV-C treatment, and suggests candidate genes, or promoter activity of related genes, that could be used in future functional and molecular biological studies of resveratrol metabolism. PMID:27148326

  4. Silage to Ella Translation

    DTIC Science & Technology

    1990-04-01

    of the form (i : lub .. upb ) :: a = b where lwb , upb are integers and a, b expressions. Since Silage is an applicative language it has single...by the following approach for sequences INT lwb = .. , upb = .. , max= TYPE integer = int/( lwb ..upb). VAR sum := [max]( ... ), a := [max]( ... [INT i...2. .rax] CASE it/i LT in OF b’l : sum[i: sum[i-1] - a[i] ESAC; and by the following for non-sequence ELLA INT lwb - .. . upb .. ,max= TYPE integer

  5. Simplifying the modal mu-calculus alternation hierarchy

    NASA Astrophysics Data System (ADS)

    Bradfield, J. C.

    In [Bra96], the strictness of the modal mu-calculus alternation hierarchy was shown by transferring a hierarchy from arithmetic; the latter was a corollary of a deep and highly technical analysis of [Lub93]. In this paper, we show that the alternation hierarchy in arithmetic can be established by entirely elementary means; further, simple examples of strict alternation depth n formulae can be constructed, which in turn give very simple examples to separate the modal hierarchy. In addition, the winning strategy formulae of parity games are shown to be such examples.

  6. United States Air Force Statistical Digest, Fiscal Year 1955. Tenth Edition

    DTIC Science & Technology

    1955-09-30

    SC": Ic )"’ll’:.S are tnc uceo m o.ri-ent.ve ses , , , ,L...Total) . 353,933 37 10 8 "- 48 14 18 , 44 12~ lu,b59 , 19 1 , 1 -, 1 9 , 19 B-25 166,513 " 9 2 1 ic 6 8 5 17 10B-26 68.072 j, 22 3 4 1, 15 5 7 16 24 B...1955 (CONTINUED) (For comparative purposes to the previous fiscal year table see Table 25, Statistical Digest 1954.), TOTAL A.CCYiPI’A..’ iCES JUL ,54

  7. ’MODESRCH’, An Improved Computer Program for Obtaining ELF/VLF/LF Mode Constants in an Earth-Ionosphere Waveguide

    DTIC Science & Technology

    1976-10-01

    0 RHO = O*C i TA-LT=iu.0 RAt T 3. Gt"AX = 50 SEP = 091 TVSt-=-1 .0 LUB=-Io0 C NUFLAG = 0 COEFi’U(1L .) b1 C UL FPU ( 21 *5UF C OEf! U ( 3 te= 4E F)’PNU...Lt20 Ili ITI TLE(K)=I BCD ( K) 11. READ 904vJITtENS(1),ENS(1) 904t FC2RMAT IF7,295XtE9.2tEIO.2) IF (H7 .LT, 0.0) GO TO 15 HTS(J) =E 1T ANC, HTS(J

  8. PHYTOCHEMICAL CONTENT IN BLUEBERRIES IS INFLUENCED BY UV ILLUMINATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The levels of phytochemicals in blueberries were found to increase after illumination with UV-C light. Phytochemicals affected included resveratrol, myricetin 3-arabinoside, quercetin 3-galactoside, quercetin 3-arabinoside, quercetin derivative, kaempferol 3-glucoside, delphinidin-3-galactoside, cy...

  9. SUPERFUND TREATABILITY CLEARINGHOUSE: PCB SEDIMENT DECONTAMINATION PROCESS-SELECTION FOR TEST AND EVALUATION

    EPA Science Inventory

    This document is a report describing the assessment of seven alternative treatment processes that show potential for decontaminating polychlorinated biphenyl (PCB)-contaminated sediments. The processes are KPEG, MODAR Supercritical Water Oxidation, Bio-Clean, Ultrasonics/UV, C...

  10. Inactivation of avirulent Yersinia pestis on food and food contact surfaces by ultraviolet light and freezing.

    PubMed

    Sommers, Christopher H; Sheen, Shiowshuh

    2015-09-01

    Yersinia pestis, the causative agent of plague, can occasionally be contracted as a naso-pharyngeal or gastrointestinal illness through consumption of contaminated meat. In this study, the use of 254 nm ultraviolet light (UV-C) to inactivate a multi-isolate cocktail of avirulent Y. pestis on food and food contact surfaces was investigated. When a commercial UV-C conveyor was used (5 mW/cm(2)/s) 0.5 J/cm(2) inactivated >7 log of the Y. pestis cocktail on agar plates. At 0.5 J/cm(2), UV-C inactivated ca. 4 log of Y. pestis in beef, chicken, and catfish, exudates inoculated onto high density polypropylene or polyethylene, and stainless steel coupons, and >6 log was eliminated at 1 J/cm(2). Approximately 1 log was inactivated on chicken breast, beef steak, and catfish fillet surfaces at a UV-C dose of 1 J/cm(2). UV-C treatment prior to freezing of the foods did not increase the inactivation of Y. pestis over freezing alone. These results indicate that routine use of UV-C during food processing would provide workers and consumers some protection against Y. pestis.

  11. Dynamic sorption of ionizable organic compounds (IOCs) and xylene from water using geomaterial-modified montmorillonite.

    PubMed

    Houari, M; Hamdi, B; Brendle, J; Bouras, O; Bollinger, J C; Baudu, M

    2007-08-25

    Adsorption of phenols and xylene onto composite material, Na-montmorillonite, activated carbon, cement and water mixture, 70%, 7%, 7% and 16% (w/w/w/w), respectively, was studied at pH values of 5.15, 4.55, 5.2 and 4.9, respectively, of phenol, 2-CP, 2-NP and xylene. Equilibrium isotherms and fixed-bed column studies were undertaken to evaluate the performance of clay-active coal-coated cement (CACC) in removing phenols from aqueous solution. Investigations revealed CACC to be a very efficient media for the removal of phenols from water. The suitability of the Langmuir adsorption model to the equilibrium data was investigated for all phenols-adsorbent systems. At the maximum sorption capacity of the composite material it was found that the uptake (mg phenols/g) of phenols increased in the order 2-CP>2-NP>phenol approximately m-xylene as do their solubilities. The LUB design approach was used to determine the equivalent length of unused bed. The lower LUB values imply a better utilization of CACC composite. A model, which considered the effect of axial dispersion, was successfully used to describe the fixed-bed operation, the axial dispersion coefficient increased significantly with solubility.

  12. Effects of molecular weight of grafted hyaluronic acid on wear initiation.

    PubMed

    Lee, Dong Woog; Banquy, Xavier; Das, Saurabh; Cadirov, Nicholas; Jay, Gregory; Israelachvili, Jacob

    2014-05-01

    Hyaluronic acid (HA) of different molecular weights (Mw) was grafted onto mica surfaces to study the effects of Mw on the conformation and wear protection properties of a grafted HA (gHA) layer in lubricin (LUB) and bovine synovial fluid (BSF) using a surface forces apparatus. The Mw of gHA had significant effects on the wear pressure (Pw), at which point the wear initiates. Increasing the gHA Mw from 51 to 2590kDa increased Pw from 4 to 8MPa in LUB and from 15 to 31MPa in BSF. The 2590kDa gHA in BSF had the best wear protection (Pw∼31MPa), even though it exhibited the highest friction coefficient (μ∼0.35), indicating that a low μ does not necessarily result in good wear protection, as is often assumed. The normal force profile indicated that BSF confines the gHA structure, making it polymer brush-like, commonly considered as an excellent structure for boundary lubrication.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-10-15

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

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

    PubMed

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

    2015-01-01

    A novel ultraviolet light irradiation (UV-C, 254 nm) process was designed as an additional safety feature for manufacturing of spray dried porcine plasma (SDPP). In Exp. 1, three 10-L batches of bovine plasma were inoculated with 10(5.2 ± 0.12) tissue culture infectious dose 50 (TCID50) of porcine parvovirus (PPV) per mL of plasma and subjected to UV-C ranging from 0 to 9180 J/L. No viable PPV was detected in bovine plasma by micro-titer assay in SK6 cell culture after UV-C at 2295 J/L. In Exp. 2, porcine plasma was subjected to UV-C (3672 J/L), then spray dried and mixed in complete mash diets. Diets were a control without SDPP (Control), UV-C SDPP either at 3% (UVSDPP3) or 6% (UVSDPP6) and non-UV-C SDPP at 3% (SDPP3) or 6% (SDPP6). Diets were fed ad libitum to 320 weaned pigs (26 d of age; 16 pens/diet; 4 pigs/pen) for 14 d after weaning and a common diet was fed d 15 to 28. During d 0 to 14, pigs fed UVSDPP3, UVSDPP6, or SDPP6 had higher (P < 0.05) weight gain and feed intake than control. During d 0 to 28, pigs fed UVSDPP3 and UVSDPP6 had higher (P < 0.05) weight gain and feed intake than control and SDPP3, and SDPP6 had higher (P < 0.05) feed intake than control. Also, pigs fed UVSDPP had higher (P < 0.05) weight gain than pigs fed SDPP. In conclusion, UV-C inactivated PPV in liquid plasma and UVSDPP used in pig feed had no detrimental effects on pig performance.

  16. Biological and photochemical degradation of cytostatic drugs under laboratory conditions.

    PubMed

    Franquet-Griell, Helena; Medina, Andrés; Sans, Carme; Lacorte, Silvia

    2017-02-05

    Cytostatic drugs, used in chemotherapy, have emerged as new environmental contaminants due to their recurrent presence in surface waters and genotoxic effects. Yet, their degradability and environmental fate is largely unknown. The aim of this study was to determine the degradation kinetics of 16 cytostatic drugs, prioritized according to their usage and occurrence in hospital and wastewater treatment plants (WWTP) effluents, through the following laboratory scale processes: hydrolysis, aerobic biodegradation, UV-C photolysis, UV-C/H2O2 and simulated solar radiation. Some drugs were unstable in milli-Q water (vincristine, vinblastine, daunorubicin, doxorubicin and irinotecan); others were photodegraded under UV-C light (melphalan and etoposide) but some others were found to be recalcitrant to biodegradation and/or UV-C, making necessary the use of advanced oxidation processes (AOPs) such as UV-C/H2O2 for complete elimination (cytarabine, ifosfamide and cyclophosphamide). Finally, radiation in a solar box was used to simulate the fate of cytostatic drugs in surface waters under natural radiation and complete removal was not observed for any drug. The degradation process was monitored using liquid chromatography coupled to high resolution mass spectrometry and pseudo-first order kinetic degradation constants were calculated. This study provides new data on the degradability of cytostatic compounds in water, thus contributing to the existing knowledge on their fate and risk in the environment.

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

    PubMed

    Espinoza, J Horacio; Mercado-Uribe, Hilda

    2017-02-01

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

  18. Multiomics in Grape Berry Skin Revealed Specific Induction of the Stilbene Synthetic Pathway by Ultraviolet-C Irradiation1

    PubMed Central

    Suzuki, Mami; Nakabayashi, Ryo; Ogata, Yoshiyuki; Sakurai, Nozomu; Tokimatsu, Toshiaki; Goto, Susumu; Suzuki, Makoto; Jasinski, Michal; Martinoia, Enrico; Otagaki, Shungo; Matsumoto, Shogo; Saito, Kazuki; Shiratake, Katsuhiro

    2015-01-01

    Grape (Vitis vinifera) accumulates various polyphenolic compounds, which protect against environmental stresses, including ultraviolet-C (UV-C) light and pathogens. In this study, we looked at the transcriptome and metabolome in grape berry skin after UV-C irradiation, which demonstrated the effectiveness of omics approaches to clarify important traits of grape. We performed transcriptome analysis using a genome-wide microarray, which revealed 238 genes up-regulated more than 5-fold by UV-C light. Enrichment analysis of Gene Ontology terms showed that genes encoding stilbene synthase, a key enzyme for resveratrol synthesis, were enriched in the up-regulated genes. We performed metabolome analysis using liquid chromatography-quadrupole time-of-flight mass spectrometry, and 2,012 metabolite peaks, including unidentified peaks, were detected. Principal component analysis using the peaks showed that only one metabolite peak, identified as resveratrol, was highly induced by UV-C light. We updated the metabolic pathway map of grape in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and in the KaPPA-View 4 KEGG system, then projected the transcriptome and metabolome data on a metabolic pathway map. The map showed specific induction of the resveratrol synthetic pathway by UV-C light. Our results showed that multiomics is a powerful tool to elucidate the accumulation mechanisms of secondary metabolites, and updated systems, such as KEGG and KaPPA-View 4 KEGG for grape, can support such studies. PMID:25761715

  19. Arsenite Oxidation by Ultrasound Combined with Ultraviolet in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Lee, Seban; Cui, Mingcan; Na, Seungmin; Khim, Jeehyeong

    2012-07-01

    This study aims to investigate the sonophotochemical oxidation of As(III) to As(V) using the synergistic effect of a strong oxidant that is a hydroxyl radical. The rate constant, k, in the ultrasound (US), ultraviolet C (UV-C), and US/UV-C processes was found to be 1.65×10-4, 3.65×10-4, and 8.31×10-4 s-1 respectively. The highest power densities were 21.26, in the case of UV-C, and 26.27 W L-1 for US. Finally, the combined US/UV-C system gave a synergistic effect value of 1.57. This was similar to the synergistic effect value of the production of hydroxyl radicals with potassium iodide (KI) solution using the same combined process. Moreover, the reaction rate of the As(III) oxidation to As(V) in the US/UV-C process increased with a gradual increase in pH. The reaction rates were found to be 1.88×10-3 at pH 11 and 8.31×10-4 s-1 at pH 7. Therefore, the reaction rate at pH 11 was 2.3 times faster than that at pH 7.

  20. Geopolymers in Construction / Zastosowanie Geopolimerów W Budownictwie

    NASA Astrophysics Data System (ADS)

    Błaszczyński, Tomasz Z.; Król, Maciej R.

    2015-03-01

    Within the framework of quests of supplementary and "healthier" binders to the production of concrete followed the development of geopolymers in construction. However the practical application of these materials is still very limited. The production of each ton of cement introduces one ton of CO2 into the atmosphere. According to various estimations, the synthesis of geopolymers absorbs 2-3 times less energy than the Portland cement and causes a generation of 4-8 times less of CO2. Geopolymeric concretes possess a high compressive strength, very small shrinkage and small creep, and they possess a high resistance to acid and sulphate corrosion. These concretes are also resistant to carbonate corrosion and possess a very high fire resistance and also a high resistance to UV radiation. W ramach poszukiwania zastępczych i "zdrowszych" spoiw do produkcji betonu nastąpił rozwój geopolimerów w budownictwie. Jednakże praktyczne zastosowanie tych materiałów jest jeszcze nadal bardzo ograniczone. Produkcja każdej tony cementu wprowadza do atmosfery tonę CO2. Według różnych szacunków, synteza geopolimerów pochłania 2-3 razy mniej energii, niż cementu portlandzkiego oraz powoduje wydzielenie 4-8 razy mniejszej ilości CO2. Do tego betony geopolimerowe posiadają wysoką wytrzymałość na ściskanie, bardzo mały skurcz i małe pełzanie oraz dają wysoką odporność na korozję kwasową i siarczanową. Betony te są także odporne na korozję węglanową i posiadają bardzo wysoką odporność ogniową, a także wysoką odporność na promieniowanie UV.

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

    PubMed

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

    2014-09-01

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

  2. Bactericidal efficiency and mode of action: a comparative study of photochemistry and photocatalysis.

    PubMed

    Pigeot-Rémy, S; Simonet, F; Atlan, D; Lazzaroni, J C; Guillard, C

    2012-06-15

    In order to compare the disinfection potential of photocatalysis and photochemistry, the effects of these two processes on bacteria in water were investigated under exposure to UV-A and UV-C. The well-known bacterial model Escherichia coli (E. coli) was used as the experimental organism. Radiation exposure was produced with an HPK 125 W lamp and the standard TiO(2) Degussa P-25 was used as the photocatalyst. Firstly, the impact of photocatalysis and photochemistry on the cultivability of bacterial cells was investigated. UV-A radiation resulted in low deleterious effects on bacterial cultivability but generated colonies of size smaller than average. UV-C photocatalysis demonstrated a greater efficiency than UV-A photocatalysis in altering bacterial cultivability. From a cultivability point of view only, UV-C radiation appeared to be the most deleterious treatment. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit was then used to assess the modifications in bacterial membrane permeability. UV-A radiation did not induce any alterations in bacterial permeability for 420 min of exposure whereas only a few minutes of exposure to UV-C radiation, with the same total radiance intensity, induced total loss of permeability. Moreover, after 20 and 60 min of exposure to UV-C and UV-A photocatalysis respectively, all bacteria lost their membrane integrity, suggesting that the bacterial envelope is the primary target of reactive oxygen species (ROS) generated at the surface of TiO(2) photocatalyst. These results were further confirmed by the formation of malondialdehyde (MDA) during the photocatalytic inactivation of bacterial cells and suggest that destruction of the cell envelope is a key step in the bactericidal action of photocatalysis. The oxidation of bacterial membrane lipids was also correlated with the monitoring of carboxylic acids, which can be considered as representatives of lipid peroxidation by-products. Finally, damages to

  3. Ultraviolet-C light inactivation of Escherichia coli O157:H7 and Listeria monocytogenes on organic fruit surfaces.

    PubMed

    Adhikari, Achyut; Syamaladevi, Roopesh M; Killinger, Karen; Sablani, Shyam S

    2015-10-01

    This study investigated UV-C light inactivation of Escherichia coli O157:H7 and Listeria monocytogenes on the surface of organic apples, pears, strawberries, red raspberries and cantaloupes. Fruit surfaces spot inoculated with cocktail strains of E. coli O157:H7 and L. monocytogenes were exposed to UV-C doses up to 11.9 kJ/m(2) at 23 °C. Fruit surface roughness, contact angle, and surface energy were determined and correlated with UV-C inactivation kinetics. Results demonstrate that bacterial pathogens on fruit surfaces respond differently to UV-C light exposure. E. coli O157:H7 on apple and pear surfaces was reduced by 2.9 and 2.1 log CFU/g, respectively when treated with UV-C light at 0.92 kJ/m(2) (60s). For berries, the reduction of E. coli O157:H7 was lower with 2.0 (strawberry) and 1.1 log CFU/g (raspberry) achieved after UV-C treatment at 7.2 kJ/m(2) (8 min) and at 10.5 kJ/m(2) (12 min), respectively. Similarly, a higher reduction of L. monocytogenes was observed on apple (1.6 log CFU/g at 3.75 kJ/m(2)) and pear (1.7 log CFU/g at 11.9 kJ/m(2)) surfaces compared to cantaloupe and strawberry surfaces (both achieved 1.0 log CFU/g at 11.9 kJ/m(2)). L. monocytogenes shows more resistance than E. coli O157:H7. Inactivation rates were higher for less hydrophobic fruits with smoother surfaces (apples and pears) as compared to fruits with rougher surfaces (cantaloupe, strawberry and raspberry). Findings indicate that UV-C light can effectively reduce E. coli O157:H7 and L. monocytogenes populations on fruit and berry surfaces. However, surface characteristics influence the efficacy of UV-C light.

  4. Magnetic properties of Ho1- x Lu x B12 solid solutions

    NASA Astrophysics Data System (ADS)

    Gabáni, S.; Gaz̆o, E.; Pristás̆, G.; Takác̆ová, I.; Flachbart, K.; Shitsevalova, N.; Siemensmeyer, K.; Sluchanko, N.

    2013-05-01

    Magnetic properties of the geometrically frustrated antiferromagnet HoB12 (with T N = 7.4 K) modified by substitution of magnetic Ho atoms through non-magnetic Lu ones are presented and discussed. In this case, in Ho1- x Lu x B12 solid solutions, both chemical pressure resulting from different Lu3+ and Ho3+ radii and magnetic dilution take place with increasing Lu content ( x) that change properties of the system. The received results show strong indication for the existence of a quantum critical point near x = 0.9, which separates the region of magnetic order (starting with HoB12 for x = 0) and the nonmagnetic region (ending with superconducting LuB12 for x = 1).

  5. Organizational, Design and Technology Issues in the Process of Protection of Underground Historic Monuments/ Probelmy Organizacyjne, Projektowe I Technologiczne W Procesie Zabezpieczania Zabytkowych Podziemi

    NASA Astrophysics Data System (ADS)

    Bartos, Maciej; Chmura, Janusz; Wieja, Tomasz

    2015-06-01

    Underground historic monuments constitute the immanent part of the cultural and natural heritage. Protecting and opening underground historic objects, as the investment aim, is a process of renewed actions taken in objects that are degraded or out of order, contributing to improvement of quality of life of residents, restoring new functions, reconstruction of social bonds. Underground historic buildings should be subjected to processes of protecting and revitalization. Determining the state of a given building and the adjustability of its spatial structure to introducing a new function or making it available to tourist purposes are the basis for these actions. Zabytkowe podziemia stanowią immanentną część dziedzictwa kulturowego i przyrodniczego. Zabezpieczenie i udostępnienie podziemnych obiektów zabytkowych, jako zamierzenia inwestycyjnego, jest procesem ponownych działań podejmowanych w zdegradowanych lub nieczynnych obiektach, przyczyniając się do poprawy jakości życia mieszkańców, przywrócenia nowych funkcji, odbudowy więzi społecznych. Podziemne obiekty zabytkowe powinny być poddane procesom zabezpieczenia i rewitalizacji. Podstawą tych działań jest określenie stanu zachowania danego obiektu oraz możliwości dostosowania jego struktury przestrzennej do wprowadzenia nowej funkcji lub udostępnienia w celach turystycznych. Zasadniczym problemem jest, na etapie organizacyjnym, brak jednolitego ustawodawstwa prawnego dotyczącego procesu zabezpieczania podziemnych obiektów. W artykule przedstawiamy zasadnicze problemy organizacyjne, projektowe i technologiczne występujące w procesie inwestycyjnym zabezpieczania podziemnych obiektów zabytkowych. Efektem tych prac jest transformacja podziemnego obiektu w strukturę przestrzenną o nowej funkcji użytkowej.

  6. Applying Active Thermography in the Non-Destructive Investigation of Historical Objects/ Zastosowanie Termowizji Aktywnej Do Badań Nieniszczących Obiektów Zabytkowych

    NASA Astrophysics Data System (ADS)

    Nowak, Henryk; Noszczyk, Paweł

    2015-06-01

    The paper pertains to the problem of historic building envelope investigation with the use of active thermography. Mainly emphasized is its application in the detection of different material inclusions in historic walls. Examples of active thermography in the reflective mode application and a description of the experimental investigation has been shown on a wall model with the inclusion of materials with significantly different thermal conductivity and heat capacity, i.e. styrofoam, steel and granite. Thermograms received for every kind of envelope are compared and analyzed. Finally, the summary and conclusion is shown along with the prospects of development and practical application of this kind of investigation in historic construction. Artykuł porusza zagadnienie wykorzystania termografii aktywnej w nieniszczących badaniach przegród budowlanych w obiektach zabytkowych. Opisane zostały potencjalne możliwości stosowania badań, takie jak: lokalizacja rodzaju zbrojenia w elementach żelbetowych, detekcja pustek powietrznych i przemurowań w przegrodach, określanie rodzaju struktury materiałowej zabytkowej przegrody lub identyfikacja ukrytych pod wartwą tynku lub farby malowideł ściennych. W pracy opisano przebieg doświadczenia z wykorzystaniem termografii aktywnej w trybie odbiciowym. W badanych modelach przegród, wewnętrzne wtrącenia materiałowe zostały wykonane ze styropianu XPS, stali oraz granitu. Otrzymane wyniki opisano za pomocą kontrastów temperaturowych (absolutny i standardowy) oraz zinterptretowano otrzymane termogramy. W podsumowaniu przedstawiono wnioski z przeprowadzonego doświadczenia. W artykule potwierdzono przydatność nieniszczących badań za pomocą termowizji aktywnej do detekcji przypowierzchniowych wtrąceń materiałowych.

  7. Studies on PVP hydrogel-supported luminol chemiluminescence: 1. Kinetic and mechanistic aspects using multivariate factorial analysis.

    PubMed

    Bastos, Erick Leite; Ciscato, Luiz Francisco Monteiro Leite; Bartoloni, Fernando Heering; Catalani, Luiz Henrique; Baader, Wilhelm Josef

    2007-01-01

    The chemiluminescent oxidation of luminol by hydrogen peroxide in the presence of hemin is revisited in an UV-C cross-linked PVP hydrogel. Chemiluminescence properties such as initial light intensity (I(0)), area of emission (S) and observed rate constants (k(obs)) are studied, varying the concentration of all reactants using a multivariate factorial approach.

  8. Effects of combination of ultraviolet light and hydrogen peroxide on inactivation of Escherichia coli O157:H7, native microbial loads, and quality of button mushrooms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mushrooms are prone to microbial spoilage and browning during growing and processing. Ultraviolet light (UV-C) has been used as an alternative technology to chemical sanitizers for food products. Hydrogen peroxide is classified as generally recognized as safe for use in foods as a bleaching and ant...

  9. Demonstrating the Influence of UV Rays on Living Things.

    ERIC Educational Resources Information Center

    Morimoto, Kouichi

    2002-01-01

    Describes an experiment that introduces students to the different types of UV rays and their effects on living things by using appropriate teaching materials and equipment. Demonstrates the effects of exposure to UV-B (fluorescent) and UV-C (germicidal) lamps by using bananas, duckweed, and the fruit fly. (Contains 14 references.) (Author/YDS)

  10. UV Treatment Enhances Flavonoid Content in Blueberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Treatment of blueberries (Vaccinium corymbosum, cv. Sierra) with UV-C at 2.15 or 4.30 kJ m-2 enhanced blueberry fruit content of flavonoids including resveratrol, myricetin 3-arabinoside, quercetin 3-galactoside, quercetin 3-arabinoside, quercetin derivative, kaempferol 3-glucoside, delphinidin-3-ga...

  11. Radiation Effects on Cyclic AMP, Cyclic GMP, and Amino Acid Levels in the CSF of the Primate

    DTIC Science & Technology

    1980-11-07

    rradiation . An analysis of brain areas obtained by biopsy of irradiated animals showed significant decreases in only the cerebellar cyclic AMP and cyclic...GMP. No appreciablk ¢±anges were found in the CSF amino acid composition. Acc. !-,’r ror UV , . c" l. __ ..:j’od I7 .... ’U r~rd0 /or cpy I NCI

  12. Inactivation of Campylobacter jejuni on poultry by ultraviolet light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter jejuni is a foodborne pathogen which is commonly associated with poultry, and is responsible for many foodborne illness outbreaks. Ultraviolet light (UV-C) is a U.S. Food and Drug Administration approved technology that can be used to treat foods and food contact surfaces. In this stud...

  13. 76 FR 20669 - Oreck Corporation; Analysis of Proposed Consent Order To Aid Public Comment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... as effective, through normal use, in killing virtually all bacteria, viruses, germs, mold and... caused by bacteria, viruses, molds, and allergens, such as the common cold, diarrhea, upset stomachs... UV-C light is effective against germs, bacteria, dust mites, mold and viruses embedded in...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. Advanced oxidation of a commercially important nonionic surfactant: investigation of degradation products and toxicity.

    PubMed

    Karci, Akin; Arslan-Alaton, Idil; Bekbolet, Miray

    2013-12-15

    The evolution of degradation products and changes in acute toxicity during advanced oxidation of the nonionic surfactant nonylphenol decaethoxylate (NP-10) with the H2O2/UV-C and photo-Fenton processes were investigated. H2O2/UV-C and photo-Fenton processes ensured complete removal of NP-10, which was accompanied by the generation of polyethylene glycols with 3-8 ethoxy units. Formation of aldehydes and low carbon carboxylic acids was evidenced. According to the acute toxicity tests carried out with Vibrio fischeri, degradation products being more inhibitory than the original NP-10 solution were formed after the H2O2/UV-C process, whereas the photo-Fenton process appeared to be toxicologically safer since acute toxicity did not increase relative to the original NP-10 solution after treatment. Temporal evolution of the acute toxicity was strongly correlated with the identified carboxylic acids being formed during the application of H2O2/UV-C and photo-Fenton processes.

  16. Ultraviolet radiation for the sterilization of contact lenses

    SciTech Connect

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

    1990-10-01

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

  17. Inactivation of avirulent Yersinia pestis on food and food contact surfaces by ultraviolet light and freezing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yersinia pestis, the causative agent of plague, can occasionally be contracted as a naso-pharangeal or gastrointestinal illness through consumption of contaminated meat. In this study, the use of 254 nm ultraviolet light (UV-C) to inactivate a multi-isolate cocktail of avirulent Y. pestis on food an...

  18. Effects of high hydrostatic pressure, ultraviolet light-C, and far-infrared treatments on the digestibility, antioxidant and antihypertensive activity of α-casein.

    PubMed

    Hu, Guanlan; Zheng, Yuanrong; Liu, Zhenmin; Xiao, Yang; Deng, Yun; Zhao, Yanyun

    2017-04-15

    Alpha-casein is the most important bioactive protein in processing technologies. This study investigated the digestibility, antioxidant and antihypertensive activities of α-casein when treated by high hydrostatic pressure (HPP), ultraviolet light-C (UV-C), and far-infrared radiation (FIR). The in vitro digestibility was modified after treatments, especially after 5min/200MPa HHP treatment. Ultra-performance liquid chromatography-tandem mass spectrometry analysis showed that one 5min/200MPa HHP treatment resulted in the highest yield of peptides. Based on the in vitro gastrointestinal digestion and antioxidant and antihypertensive activity assays, HHP increased the angiotensin converting enzyme inhibitory activity at different levels. The 15min UV-C treatment resulted in the highest antioxidant DPPH radical-scavenging activity, while the 15min UV-C and FIR treatments had higher angiotensin converting enzyme inhibitory and antioxidant activities than those of 5min treatments. This study revealed that HHP, UV-C and FIR treatments increased the antioxidant and antihypertensive activities of α-casein.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  1. Draft Genome Sequence of Hymenobacter sp. Strain AT01-02, Isolated from a Surface Soil Sample in the Atacama Desert, Chile

    PubMed Central

    Paulino-Lima, Ivan Glaucio; Fujishima, Kosuke; Rothschild, Lynn Justine; Jensen, Peter Ruhdal

    2016-01-01

    Here, we report the 5.09-Mb draft genome sequence of Hymenobacter sp. strain AT01-02, which was isolated from a surface soil sample in the Atacama Desert, Chile. The isolate is extremely resistant to UV-C radiation and is able to accumulate high intracellular levels of Mn/Fe. PMID:26868392

  2. Multiple transport systems mediate virus-induced acquired resistance to oxidative stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we report the phenomenon of acquired cross-tolerance to oxidative (UV-C and H2O2) stress in Nicotiana benthamiana plants infected with Potato virus X (PVX) and investigate the functional expression of transport systems in mediating this phenomenon. By combining multiple approaches, we...

  3. Genome-wide analyses of the transcriptomes of salicylic acid-deficient versus wild-type plants uncover Pathogen and Circadian Controlled 1 (PCC1) as a regulator of flowering time in Arabidopsis.

    PubMed

    Segarra, Silvia; Mir, Ricardo; Martínez, Cristina; León, José

    2010-01-01

    Salicylic acid (SA) has been characterized as an activator of pathogen-triggered resistance of plants. SA also regulates developmental processes such as thermogenesis in floral organs and stress-induced flowering. To deepen our knowledge of the mechanism underlying SA regulation of flowering time in Arabidopsis, we compared the transcriptomes of SA-deficient late flowering genotypes with wild-type plants. Down- or up-regulated genes in SA-deficient plants were screened for responsiveness to ultraviolet (UV)-C light, which accelerates flowering in Arabidopsis. Among them, only Pathogen and Circadian Controlled 1 (PCC1) was up-regulated by UV-C light through a SA-dependent process. Moreover, UV-C light-activated expression of PCC1 was also dependent on the flowering activator CONSTANS (CO). PCC1 gene has a circadian-regulated developmental pattern of expression with low transcript levels after germination that increased abruptly by day 10. RNAi plants with very low expression of PCC1 gene were late flowering, defective in UV-C light acceleration of flowering and contained FLOWERING LOCUS T (FT) transcript levels below 5% of that detected in wild-type plants. Although PCC1 seems to function between CO and FT in the photoperiod-dependent flowering pathway, transgenic plants overexpressing a Glucocorticoid Receptor (GR)-fused version of CO strongly activated FT but not PCC1 after dexamethasone treatment.

  4. Application of ultraviolet-C light on oranges for the inactivation of postharvest wound pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Germicidal effects of ultraviolet-C (UV-C) light on the postharvest wound pathogens of citrus fruits namely Penicillium digitatum and Penicillium italicum were investigated. P. digitatum and P. italicum spores were inoculated (4.00 – 4.50 log cfu/ orange) onto Washington navel oranges (Citrus sinens...

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  6. Suppressive action of near-ultraviolet light on ouabain resistance induced by far-ultraviolet light in Chinese hamster cells.

    PubMed

    Suzuki, F; Han, A; Hill, C K; Elkind, M M

    1983-03-01

    The interaction between ultraviolet light (UV-C) from germicidal lamps (254 nm) and near-ultraviolet light (UV-B) from Westinghouse Sun Lamps (290-345 nm) was studied in Chinese hamster V79 cells by measuring the effectiveness of combined exposures to induce the resistance to 6-thioguanine or to ouabain. Exposure of cells to a conditioning dose of UV-B (approximately 70% survival) results in significant inhibition of the induction by UV-C of cells resistant to ouabain. The inhibition is lost, however, if cells are incubated for 12 h at 37 degrees C between exposures. Inhibition is also observed when cells are preirradiated with a dose of UV-B filtered with polystyrene (300-345 nm) which, in itself, has no effect on cell killing. Conditioning exposures of unfiltered or filtered UV-B light do not inhibit the induction of 6-thioguanine-resistant cells by UV-C light, and the effects of UV-B and UV-C light are largely independent.

  7. Expression of Nudix hydrolase genes in barley under UV irradiation

    NASA Astrophysics Data System (ADS)

    Tanaka, Sayuri; Sugimoto, Manabu; Kihara, Makoto

    Seed storage and cultivation should be necessary to self-supply foods when astronauts would stay and investigate during long-term space travel and habitation in the bases on the Moon and Mars. Thought the sunlight is the most importance to plants, both as the ultimate energy source and as an environmental signal regulating growth and development, UV presenting the sunlight can damage many aspects of plant processes at the physiological and DNA level. Especially UV-C, which is eliminated by the stratospheric ozone layer, is suspected to be extremely harmful and give a deadly injury to plants in space. However, the defense mechanism against UV-C irradiation damage in plant cells has not been clear. In this study, we investigated the expression of Nudix hydrolases, which defense plants from biotic / abiotic stress, in barley under UV irradiation. The genes encoding the amino acid sequences, which show homology to those of 28 kinds of Nudix hydrolases in Arabidopsis thaliana, were identified in the barley full-length cDNA library. BLAST analysis showed 14 kinds of barley genes (HvNUDX1-14), which encode the Nudix motif sequence. A phylogenetic tree showed that HvNUDX1, HvNUDX7, HvNUDX9 and HvNUDX11 belonged to the ADP-ribose pyrophosphohydrolase, ADP-sugar pyrophosphohydrolase, NAD(P)H pyrophosphohydrolase and FAD pyrophosphohydrolase subfamilies, respectively, HvNUDX3, HvNUDX6, and HvNUDX8 belonged to the Ap _{n}A pyrophosphohydrolase subfamilies, HvNUDX5 and HvNUDX14 belonged to the coenzyme A pyrophosphohydrolase subfamilies, HvNUDX12 and HvNUDX13 belonged to the Ap _{4}A pyrophosphohydrolase subfamilies. Induction of HvNUDX genes by UV-A (340nm), UV-B (312nm), and UV-C (260nm) were analyzed by quantitative RT-PCR. The results showed that HvNUDX4 was induced by UV-A and UV-B, HvNUDX6 was induced by UV-B and UV-C, and HvNUDX7 and HvNUDX14 were induced by UV-C, significantly. Our results suggest that the response of HvNUDXs to UV irradiation is different by UV

  8. Effects of photoperiod regimes and ultraviolet-C radiations on biosynthesis of industrially important lignans and neolignans in cell cultures of Linum usitatissimum L. (Flax).

    PubMed

    Anjum, Sumaira; Abbasi, Bilal Haider; Doussot, Joël; Favre-Réguillon, Alain; Hano, Christophe

    2017-02-01

    Lignans and neolignans are principal bioactive components of Linum usitatissimum L. (Flax), having multiple pharmacological activities. In present study, we are reporting an authoritative abiotic elicitation strategy of photoperiod regimes along with UV-C radiations. Cell cultures were grown in different photoperiod regimes (24h-dark, 24h-light and 16L/8D h photoperiod) either alone or in combination with various doses (1.8-10.8kJ/m(2)) of ultraviolet-C (UV-C) radiations. Secoisolariciresinol diglucoside (SDG), lariciresinol diglucoside (LDG), dehydrodiconiferyl alcohol glucoside (DCG), and guaiacylglycerol-β-coniferyl alcohol ether glucoside (GGCG) were quantified by using reverse phase-high performance liquid chromatography (RP-HPLC). Results showed that the cultures exposed to UV-C radiations, accumulated higher levels of lignans, neolignans and other biochemical markers than cultures grown under different photoperiod regimes. 3.6kJ/m(2) dose of UV-C radiations resulted in 1.86-fold (7.1mg/g DW) increase in accumulation of SDG, 2.25-fold (21.6mg/g DW) in LDG, and 1.33-fold (9.2mg/g DW) in GGCG in cell cultures grown under UV+photoperiod than their respective controls. Furthermore, cell cultures grown under UV+dark showed 1.36-fold (60.0mg/g DW) increase in accumulation of DCG in response to 1.8kJ/m(2) dose of UV-C radiations. Smilar trends were observed in productivity of SDG, LDG and GGCG. Additionally, 3.6kJ/m(2) dose of UV-C radiations also resulted in 2.82-fold (195.65mg/l) increase in total phenolic production, 2.94-fold (98.9mg/l) in total flavonoid production and 1.04-fold (95%) in antioxidant activity of cell cultures grown under UV+photoperiod. These findings open new dimensions for feasible production of biologically active lignans and neolignans by Flax cell cultures.

  9. Photolytic degradation of the β-blocker nebivolol in aqueous solution.

    PubMed

    Salma, Alaa; Lutze, Holger V; Schmidt, Torsten C; Tuerk, Jochen

    2017-03-13

    Nebivolol (NEB) is one of the top-sold prescription drugs belonging to the third generation of beta-blockers. However, so far, occurrence data in the environment are lacking. Within this study NEB has been found for the first time in effluent samples of wastewater treatment plants in Germany with an average concentration of 13 ng L(-1). Its photodegradation behavior in the environment and in technical processes is largely unknown. To fill this gap, three different UV treatment procedures (UV-C at 254 nm, UV-B at 312 nm and UV-A at 365 nm) were investigated in three different matrices: pure water, pure water in presence of the hydroxyl radical (OH) scavenger tert.-butanol and real wastewater. No elimination was observed during UV-A treatment. In contrast, NEB degradation during UV-B and UV-C treatment followed pseudo first order reaction kinetics, with highest removal rate during UV-C treatment in pure water (k = 7.8 × 10(-4) s(-1)). The rate constant for UV-C irradiation decreased to 2.9 × 10(-4) s(-1) in the presence of the OH scavenger and in the presence of the wastewater matrix. The rate constant for the UV-B lamp was 4.4 × 10(-4) s(-1), Three transformation products were identified after UV-B and UV-C photolytic degradation using high resolution mass spectrometry. The main photoreaction is the substitution of the fluorine atoms of NEB by hydroxyl groups. A photolytic cleavage of the CF bond can be excluded as the high bond dissociation energy of aromatic CF bonds (525 kJ mol(-1)), exceeds the energy of electromagnetic radiation applied in the present study (≥254 nm, i.e., max. 471 kJ E(-1)). The quantum yields for NEB degradation for the UV-C lamp achieved in pure water, the OH scavenged system and wastewater matrix were Φdeg = 0.53, 0.19 and 0.22, respectively. For UV-B Φdeg was 0.023 ± 0.003, noticeable differences in quantum yield were not found. The photooxidation involves reactive oxygen species such as superoxide and

  10. The Problem of Form in Objects under Redevelopment (On the Basis of Bytom Market Square Redevelopment Design) / Problem Formy W Obiektach Przebudowywanych (Na Przykładzie Projektu Realizacyjnego Przebudowy Bytomskiego Rynku)

    NASA Astrophysics Data System (ADS)

    Maryńczuk, Paweł

    2015-03-01

    The author believes that if a designer has performed many design or research works entailing solutions to various problems, it is recommendable to consider and become aware of previously used methods whose application might have been unwitting or instinctive. The outcome of such reflection can be worth describing and recording in order to formulate a set of guidelines useful in the future. Such methods, being intuitive in nature, are often tied to the designer's subconsciousness, thus are rarely expressed in a clear manner. By using own methods a designer can prove that space should be composed in a given way in order to address specific needs and defined objectives. All this is aimed at preventing accidental formation of space. An example of reasoning serving the aforementioned purpose can be found in a method referred to as CQC or Composition Quality Control, the application of which facilitates intentional shaping of an architectural piece of work. Autor uważa uważa, że jeśli projektant ma za sobą wiele prac projektowych lub też prac badawczych, które połączone były z rozwiązywaniem różnych problemów, to warto zastanowić się i uświadomić sobie sposoby, które dotychczas - może nieświadomie lub odruchowo - były stosowane. Wynik refleksji warto opisać i zapisać po to, żeby ująć go w układ wskazań na przyszłość. Metody te, mając charakter intuicyjny, często związane są z podświadomością projektanta, w związku z tym rzadko można spotkać je jako wyrażone w sposób wyraźny. Stosując metody własne można dowieść, że przestrzeń winna być komponowana tak, a nie inaczej dla określonych potrzeb i wytyczonych celów tak, aby jej forma nie była przypadkowa. Przykładem takiego rozumowania jest przyjeta metoda KJK, której zastosowanie pomaga w swiadomym kształtowaniu dzieła architektonicznego.

  11. Ultraviolet induction of antifungal activity in plants.

    PubMed

    Schumpp, O; Bruderhofer, N; Monod, M; Wolfender, J-L; Gindro, K

    2012-11-01

    Ultraviolet-C irradiation as a method to induce the production of plant compounds with antifungal properties was investigated in the leaves of 18 plant species. A susceptibility assay to determine the antifungal susceptibility of filamentous fungi was developed based on an agar dilution series in microtiter plates. UV irradiation strongly induced antifungal properties in five species against a clinical Fusarium solani strain that was responsible for an onychomycosis case that was resistant to classic pharmacological treatment. The antifungal properties of three additional plant species were either unaffected or reduced by UV-C irradiation. This study demonstrates that UV-C irradiation is an effective means of modulating the antifungal activity of very diverse plants from a screening perspective.

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

    PubMed Central

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

    2016-01-01

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

  13. Cumulative effects from repeated exposures to ultraviolet radiation

    SciTech Connect

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

    1981-05-01

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

  14. Effect of photochemical treatment on the biocompatibility of a commercial nonionic surfactant used in the textile industry.

    PubMed

    Arslan-Alaton, Idil; Erdinc, Elif

    2006-10-01

    The degradability of surfactants is a frequent and complex issue arising both at domestic as well as industrial treatment facilities. The present paper describes a laboratory study conducted to elucidate the photochemical and biochemical treatability of a nonionic, alkyl polyethylene ether-based surfactant formulation commonly used in the textile preparation stage. The application of H(2)O(2)/UV-C advanced photochemical oxidation appeared to be a suitable treatment alternative and 90% COD removal (COD(0) approximately 500 mg/L) could be achieved under optimized process conditions. A significant COD removal efficiency (74%) could also be reached after biodegradation (final COD=135 mg/L) of the surfactant; however, necessitated an acclimation period of at least 6 weeks for the achievement of steady-state conditions. H(2)O(2)/UV-C treatment efficiency was seriously retarded upon elevation of the initial COD to around 1000 mg/L, resulting in 46% COD and 38% TOC removal after 120 min photochemical oxidation (H(2)O(2,0)=1020 mg/L; pH(0)=9.1). The BOD(5)/COD ratio increased from 0.23 to 0.31 after the application of H(2)O(2)/UV-C revealing that photochemical pretreatment may have a positive effect on the ultimate biodegradation of the nonionic surfactant. Although the time required for activated sludge treatment to reach steady-state conditions could be reduced to 3 weeks for the photochemically pretreated surfactant formulation biochemical COD removal efficiency dramatically decreased from 74% to 39% for the nonionic surfactant being subjected to H(2)O(2)/UV-C pretreatment (ultimate COD after activated sludge treatment=265 mg/L).

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

    PubMed

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

    2016-01-01

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

  16. Inhibition of apoptosis by 2,3,7,8-tetrachlorodibenzo-p-dioxin depends on protein biosynthesis.

    PubMed

    Chopra, Martin; Gährs, Maike; Haben, Melina; Michels, Christine; Schrenk, Dieter

    2010-08-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic persistent organic pollutant. Most of the toxic effects of TCDD are believed to be mediated by high-affinity binding to the aryl hydrocarbon receptor (AhR) and subsequent effects on gene transcription and protein expression. TCDD causes cancer in multiple tissues in different animal species and is classified as a class 1 human carcinogen. In initiation-promotion studies, TCDD was shown to be a potent liver-tumor promotor. Among other theories it has been hypothesized that TCDD promotes tumor growth by preventing initiated cells from correctly executing apoptosis. In this study, we examined the effects of TCDD on apoptosis induced by UV-C light, ochratoxin A (OTA), and cycloheximide (CHX) in primary rat hepatocytes. Both UV-C light and OTA caused caspase activation and nuclear apoptotic effects. CHX did not activate caspases but nevertheless caused DNA fragmentation and chromatin condensation. TCDD inhibited UV-C light-induced apoptosis and this effect seemed to be dependent on AhR-activation as was shown by employing an AhR antagonist. In contrast to UV-C light-induced apoptosis, TCDD failed to protect primary rat hepatocytes from OTA- or CHX-induced apoptosis. Since both of these compounds inhibit protein biosynthesis as was demonstrated by measuring the incorporation of radiolabeled leucin and protein expression of cytochrome P450 1A1, we propose that the inhibition of apoptosis by TCDD depends on protein biosynthesis. Either TCDD induces some anti-apoptotic protein in an AhR-dependent manner or inhibits pro-apoptotic proteins induced by UV irradiation.

  17. Abiotic stresses sequentially applied enhance natural resistance and reduce postharvest decay.

    PubMed

    D'Hallewin, G; Molinu, G M; Dore, A; Venditti, T; Rodov, V

    2009-01-01

    The feasibility to restrain citrus green mould (Penicillium digitatum Sacc.) during storage, by means of induced natural resistance, was investigated following combined heat and ultravioLet light C (254 nm, UV-C) treatments. Heat treatment (HT) was performed by keeping Citrus fruits in a humid saturated room at 36 degrees C for 36 h while, the UV-C light treatment (254 nm) was carried out by illuminating the fruits with 3 or 6 kJm(-2). Physical treatments were sequential and reversely applied to un-inoculated or to 24 h-old inoculated lemons or oranges. Then, fruits were stored for 30 days at 8 or 5 degrees C with 95% relative humidity (RH) followed by a 6 day simulated marketing period at 20 degrees C and 75% RH. Constitutive (cuticle and epicuticular wax) and induced resistance (scoparone biosynthesis) were monitored and the variation in natural resistance was correlated to the decay development. HT influenced positively the constitutive factors of resistance by reducing or delaying cuticular cracking and by remodelling the epicuticular wax layer. Following HT the synthesis of scoparone took place only in the albedo of wounds and was greater when fruits were inoculated. Following UV-C illumination, scoparone accumulated rapidly in the outer rind (flavedo) but, particularly with 6 kJm(-2), favoured cuticular fracturing during storage. Sequential treatments resulted significantly more effective in controlling decay on either, inoculated and non inoculated fruit. The best control of green mould during storage of lemons and oranges was obtained when HT preceded 6 kJm(-2) UV-C illumination with 52 and 45% reduction of natural decay in fruit stored at 8 degrees C compared to the control, respectively.

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

    PubMed

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

    2016-01-01

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

  19. Ultraviolet light photobiology of the protozoan Tetrahymena pyriformis and chemical reactivation of DNA damage

    SciTech Connect

    Wheeler, J.S.

    1988-01-01

    The tunable dye laser was developed in order to perform UV-B and UV-C (254-320 nm) action spectra studies on several different organisms. Using the laser, action spectra studies have been performed for Escherichia coli, Saccharomyces, Chlamydomonas, Caenorhabditis elegans, Paramecium, and Tetrahymena pyriformis. Studies generally indicate increasing LD{sub 50} values with increasing wavelength. Two notable findings were made: (1) The action spectra does not follow the DNA absorption spectra at 280, 290 and 295 nm; (2) The repair competent/repair defective sensitization factor does not remain constant throughout the wavelength region. In addition it was found that the repair defective strain of E. coli, Bs-1, showed an increase in survival with increasing UV irradiation, at certain dose levels. Further experiments were designed to better characterize the reactivation. Tetrahymena were exposed to UV-C and reactivated with methyl methanesulfonate (MMS) and 4-nitro quinoline oxide (4-NQO). In both cases survival was seen to increase after chemical exposure. Likewise, UV-C was found to reactivate chemical damage (MMS).

  20. The capacity of antioxidant protection during modulated ageing of bean (Phaseolus vulgaris L.) cotyledons. 1. The antioxidant enzyme activities.

    PubMed

    Procházková, D; Wilhelmová, N

    2007-01-01

    Reactive oxygen species are known to increase in plant senescence. We investigated the participation of antioxidative enzymes in initiation of cotyledon senescence. Senescence of bean (Phaseolus vulgaris L.) cotyledons was modulated by UV C irradiation and by the decapitation of plant apices. Senescence was accompanied by a decrease of protein content and by a decrease of photochemical efficiency. A drop in activity of antioxidative enzymes preceded the onset of senescence in control plants. In cotyledons with prolonged life span, the decrease of antioxidant activities and the markers of senescence onset appeared at a similar age as in controls. Thus we presumed that the period from senescence initiation to cotyledon abscission was extended. On the other hand, in UV C irradiated plants we did not observe actual senescence initiation, and antioxidant enzymes although elevated, did not effectively play their role. The decrease of antioxidant enzymes activity and the markers of senescence appeared at a similar age both in control and in decapitated (D) plants, so we can presume that we prolonged mainly the period from senescence onset to cotyledon abscission in D plants. In UV C irradiated plants the antioxidative enzymes were probably destroyed before the process of senescence could begin.

  1. The effect of ultraviolet treatment on enzymatic activity and total phenolic content of minimally processed potato slices.

    PubMed

    Teoh, Li Shing; Lasekan, Ola; Adzahan, Noranizan Mohd; Hashim, Norhashila

    2016-07-01

    In this work, potato slices were exposed to different doses of UV-C irradiation (i.e. 2.28, 6.84, 11.41, and 13.68 kJ m(-2)) with or without pretreatment [i.e. ascorbic acid and calcium chloride (AACCl) dip] and stored at 4 ± 1 °C. Changes in enzymatic activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), as well as total phenolic content (TPC) were investigated after 0, 3, 7 and 10 days of storage. Results showed that untreated and UV-C treated potato slices at 13.68 kJ m(-2) dosage level showed significantly higher PPO, POD and PAL activities. Conversely, untreated potato slices showed the lowest TPC during storage period. Potato slices subjected to AACCl dip plus UV-C at 6.84 kJ m(-2) produced lower PPO, POD and PAL activities, as well as maintained a high TPC during storage.

  2. UV radiation effects on a DNA repair enzyme: conversion of a [4Fe-4S](2+) cluster into a [2Fe-2S] (2+).

    PubMed

    Folgosa, Filipe; Camacho, Inês; Penas, Daniela; Guilherme, Márcia; Fróis, João; Ribeiro, Paulo A; Tavares, Pedro; Pereira, Alice S

    2015-03-01

    Organisms are often exposed to different types of ionizing radiation that, directly or not, will promote damage to DNA molecules and/or other cellular structures. Because of that, organisms developed a wide range of response mechanisms to deal with these threats. Endonuclease III is one of the enzymes responsible to detect and repair oxidized pyrimidine base lesions. However, the effect of radiation on the structure/function of these enzymes is not clear yet. Here, we demonstrate the effect of UV-C radiation on E. coli endonuclease III through several techniques, namely UV-visible, fluorescence and Mössbauer spectroscopies, as well as SDS-PAGE and electrophoretic mobility shift assay. We demonstrate that irradiation with a UV-C source has dramatic consequences on the absorption, fluorescence, structure and functionality of the protein, affecting its [4Fe-4S] cluster and its DNA-binding ability, which results in its inactivation. An UV-C radiation-induced conversion of the [4Fe-4S](2+) into a [2Fe-2S](2+) was observed for the first time and proven by Mössbauer and UV-visible analysis. This work also shows that the DNA-binding capability of endonuclease III is highly dependent of the nuclearity of the endogenous iron-sulfur cluster. Thus, from our point of view, in a cellular context, these results strengthen the argument that cellular sensitivity to radiation can also be due to loss of radiation-induced damage repair ability.

  3. Photovoltaic powered ultraviolet and visible light-emitting diodes for sustainable point-of-use disinfection of drinking waters.

    PubMed

    Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas; Jagals, Paul; Stuetz, Richard

    2014-09-15

    For many decades, populations in rural and remote developing regions will be unable to access centralised piped potable water supplies, and indeed, decentralised options may be more sustainable. Accordingly, improved household point-of-use (POU) disinfection technologies are urgently needed. Compared to alternatives, ultraviolet (UV) light disinfection is very attractive because of its efficacy against all pathogen groups and minimal operational consumables. Though mercury arc lamp technology is very efficient, it requires frequent lamp replacement, involves a toxic heavy metal, and their quartz envelopes and sleeves are expensive, fragile and require regular cleaning. An emerging alternative is semiconductor-based units where UV light emitting diodes (UV-LEDs) are powered by photovoltaics (PV). Our review charts the development of these two technologies, their current status, and challenges to their integration and POU application. It explores the themes of UV-C-LEDs, non-UV-C LED technology (e.g. UV-A, visible light, Advanced Oxidation), PV power supplies, PV/LED integration and POU suitability. While UV-C LED technology should mature in the next 10 years, research is also needed to address other unresolved barriers to in situ application as well as emerging research opportunities especially UV-A, photocatalyst/photosensitiser use and pulsed emission options.

  4. Occupant UV exposure measurements for upper-room ultraviolet germicidal irradiation.

    PubMed

    Milonova, Sonya; Rudnick, Stephen; McDevitt, James; Nardell, Edward

    2016-06-01

    The threshold limit value (TLV) guideline for ultraviolet (UV) radiation specifies that irradiance measurements to ensure occupant safety be taken over an angle of 80° at the sensor. The purpose of this study was to evaluate the effect of an 80° field of view (FOV) tube on lower room UV-C irradiation measurements. Measurements were made in an experimental chamber at a height of 1.73m with and without an FOV tube. The FOV tube reduced the lower room irradiance readings by 18-34%, a statistically significant reduction compared to the bare sensor. An 80° FOV tube should be used for lower room irradiance measurements to comply with the TLV guideline. The resulting lower readings would allow more UV-C radiation in the upper room without compromising occupant safety. More UV-C radiation in the upper room could increase efficacy of UVGI systems for reducing transmission of airborne infectious diseases. In addition, recommendations are made to standardize lower room irradiance measurement techniques.

  5. Integrated photochemical and biological treatment of a commercial textile surfactant: process optimization, process kinetics and COD fractionation.

    PubMed

    Arslan-Alaton, Idil; Cokgor, Emine Ubay; Koban, Baris

    2007-07-31

    The biodegradability of surfactants is a frequent and complex issue arising both at domestic as well as industrial treatment facilities. In the present experimental study, the integrated photochemical (H(2)O(2)/UV-C) and biochemical (activated sludge) treatment of a commercial grade nonionic/anionic textile surfactant formulation was investigated. Photochemical baseline experiments have shown that once the initial pH and H(2)O(2) dose were optimized, practically complete COD removal (COD(o)=500+/-30mgL(-1)) could be achieved. Once the COD was elevated to values being typical for the textile fabric preparation stage, treatment efficiency was seriously retarded provided that the photochemical treatment conditions remained constant. Moreover, a definite relationship existed between H(2)O(2) consumption and COD removal for H(2)O(2)/UV-C advanced oxidation of the textile surfactant. In the second part of the study, COD abatement was modeled for the biodegradation of untreated and photochemically pretreated textile surfactant formulation according to their COD fractions. Results have indicated that the readily biodegradable and rapidly hydrolysable COD fractions of the textile surfactant solution could be appreciably increased upon exposure to an optimum H(2)O(2) concentration (60mM; i.e. 2.1g H(2)O(2) (g COD(o))(-1)) and extended UV-C irradiation times (i.e. 90 and 120min).

  6. Autophosphorylation, electrophoretic mobility and immunoreaction of oat phototropin 1 under UV and blue Light.

    PubMed

    Knieb, Elke; Salomon, Michael; Rüdiger, Wolfhart

    2005-01-01

    Phototropins are UV-A/blue light photoreceptors containing two flavin mononucleotide (FMN)-binding domains, light, oxygen and voltage (LOV)1 and LOV2, of which LOV2 is more sensitive toward light and more important for the physiological response compared with LOV1. Some physiological responses are plant phototropism, chloroplast migration and stomatal opening. Oat phototropin 1 together with light-dependent autophosphorylation shows a reduced electrophoretic mobility and reduced immunoreaction against a heterologous antiserum; both effects were suggested to be caused by phosphorylation at the same sites (M. Salomon, E. Knieb, T. von Zeppelin and W. Rudiger [2003] Biochemistry 42, 4217-4225). In this study, we show that both effects can be separated from each other: at low temperature, reduced immunoreaction preceded the mobility shift, and irradiation with UV-C light led to the mobility shift without the loss of immunoreactivity. We demonstrated that UV-C light at 280 nm, which does not match any absorption maximum of FMN, leads to autophosphorylation of phototropin. It is hypothesized that UV-C light causes differential activation of the LOV domains via energy transfer from aromatic amino acids.

  7. Antibacterial and physical effects of modified chitosan based-coating containing nanoemulsion of mandarin essential oil and three non-thermal treatments against Listeria innocua in green beans.

    PubMed

    Severino, Renato; Vu, Khanh Dang; Donsì, Francesco; Salmieri, Stephane; Ferrari, Giovanna; Lacroix, Monique

    2014-11-17

    The antimicrobial activity against Listeria innocua of three different combined non-thermal treatments, along with the impact on color and texture on green bean samples, was evaluated. In this study a bioactive coating formulation based on modified chitosan containing 0.05% nanoemulsion of mandarin essential oil was tested in combination with γ-irradiation, UV-C and ozonated water treatments, and the results in terms of antimicrobial activity, color and texture changes, were evaluated during 14 days storage. The combined coating and γ-irradiation treatment gave promising results, showing 3.3 log CFU/g initial microbial reduction, and exhibiting a strong synergistic antimicrobial effect. The treatment based on UV-C and coating formulation allowed a 3 log CFU/g reduction of initial L. innocua population on samples, showing a good residual antimicrobial activity and preventing loss of firmness and color changes during storage. The combined treatment of coating and ozonated water did not show any synergistic or additive antimicrobial effect, but they showed an impact on firmness and color. In conclusion UV-C and γ-irradiation treatments, in combination with the bioactive coating, represent an effective approach to control the growth of L. innocua on vegetable foods.

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

    PubMed

    Meng, Xiangpeng; Chan, Wan

    2017-02-15

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

  9. A comparative study of the bactericidal activity and daily disinfection housekeeping surfaces by a new portable pulsed UV radiation device.

    PubMed

    Umezawa, Kazuo; Asai, Satomi; Inokuchi, Sadaki; Miyachi, Hayato

    2012-06-01

    Daily cleaning and disinfecting of non-critical surfaces in the patient-care areas are known to reduce the occurrence of health care-associated infections. However, the conventional means for decontamination of housekeeping surfaces of sites of frequent hand contact such as manual disinfection using ethanol wipes are laborious and time-consuming in daily practice. This study evaluated a newly developed portable pulsed ultraviolet (UV) radiation device for its bactericidal activity in comparison with continuous UV-C, and investigated its effect on the labor burden when implemented in a hospital ward. Pseudomonas aeruginosa, Multidrug-resistant P. aeruginosa, Escherichia coli, Acinetobacter baumannii, Amikacin and Ciprofloxacin-resistant A. baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus cereus were irradiated with pulsed UV or continuous UV-C. Pulsed UV and continuous UV-C required 5 and 30 s of irradiation, respectively, to attain bactericidal activity with more than 2Log growth inhibition of all the species. The use of pulsed UV in daily disinfection of housekeeping surfaces reduced the working hours by half in comparison to manual disinfection using ethanol wipes. The new portable pulsed UV radiation device was proven to have a bactericidal activity against critical nosocomial bacteria, including antimicrobial-resistant bacteria after short irradiation, and was thus found to be practical as a method for disinfecting housekeeping surfaces and decreasing the labor burden.

  10. Artificial neural network modeling of photocatalytic removal of a disperse dye using synthesized of ZnO nanoparticles on montmorillonite.

    PubMed

    Kıranşan, Murat; Khataee, Alireza; Karaca, Semra; Sheydaei, Mohsen

    2015-04-05

    In this study, the photocatalytic ability of ZnO/Montmorilonite (ZnO/MMT) nanocomposite under UV-A, UV-B and UV-C radiation was investigated. ZnO nanoparticles were synthesized on the surface of MMT and used as photocatalyst in decolorization of Disperse Red 54 (DR54) solution. Synthesized nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) techniques and nitrogen adsorption/desorption isotherms curves. The average width of synthesized ZnO particles is in the range of 30-45 nm. Effect of UV light regions, initial dye concentration, initial dosage of nanocomposite, and reusability of catalyst was studied on decolorization efficiency. The highest decolorization efficiency was achieved under UV-C radiation. A three-layered feed forward back propagation artificial neural network model was developed to predict the photocatalysis of DR54 under UV-C radiation. According to ANN model the ZnO/MMT dosage with a relative importance of 49.21% is the most influential parameter in the photocatalytic decolorization process.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  12. Mechanistic study of photo-oxidation of Bisphenol-A (BPA) with hydrogen peroxide (H2O2) and sodium persulfate (SPS).

    PubMed

    Sharma, Jyoti; Mishra, I M; Kumar, Vineet

    2016-01-15

    The removal of Bisphenol-A (BPA) from contaminated water using advanced oxidation methods such as UV-C assisted oxidation by hydrogen peroxide (H2O2) and sodium persulfate (SPS) has been reported by the authors earlier (Sharma et al., 2015a). In the present study, the authors report the removal of BPA from aqueous solution by the above two methods and its degradation mechanism. UV-C light (254 nm wavelength, 40 W power) was applied to BPA contaminated water at natural pH (pHN) under room temperature conditions. Experiments were carried out with the initial BPA concentration in the range of 0.04 mM-0.31 mM and the oxidant/BPA molar ratio in the range of 294:1-38:1 for UV-C/H2O2 and 31.5-4.06:1 for UV-C/SPS systems. The removal of BPA enhanced with decreasing BPA concentration. The total organic carbon also decreased with the UV-C irradiation time under optimum conditions ([H2O2]0 = 11.76 mM; [SPS]0 = 1.26 mM; temperature (29 ± 3 °C). Competition of BPA for reaction with HO or [Formula: see text] radicals at its higher concentrations results in a decrease in the removal of BPA. The intermediates with smaller and higher molecular weights than that of BPA were found in the treated water. Based on GC-MS and FTIR spectra of the reaction mixture, the formation of hydroxylated by-products testified the HO mediated oxidation pathway in the BPA degradation, while the formation of quinones and phenoxy phenols pointed to the [Formula: see text] dominating pathway through the formation of hydroxycyclohexadienyl (HCHD) and BPA phenoxyl radicals. The main route of BPA degradation is the hydroxylation followed by dehydration, coupling and ring opening reactions.

  13. Homeodomain-interacting protein kinase 2 regulates DNA damage response through interacting with heterochromatin protein 1γ.

    PubMed

    Akaike, Y; Kuwano, Y; Nishida, K; Kurokawa, K; Kajita, K; Kano, S; Masuda, K; Rokutan, K

    2015-06-01

    Homeodomain-interacting protein kinase 2 (HIPK2) is a potential tumor suppressor that has a crucial role in the DNA damage response (DDR) by regulating cell-cycle checkpoint activation and apoptosis. However, it is unclear whether HIPK2 exerts distinct roles in DNA damage repair. The aim of this study was to identify novel target molecule(s) of HIPK2, which mediates HIPK2-dependent DNA damage repair. HIPK2-knockdown human colon cancer cells (HCT116) or hipk1/hipk2 double-deficient mouse embryonic fibroblasts could not remove histone H2A.X phosphorylated at Ser139 (γH2A.X) after irradiation with a sublethal dose (10 J/m(2)) of ultraviolet (UV)-C, resulting in apoptosis. Knockdown of HIPK2 in p53-null HCT116 cells similarly promoted the UV-C-induced γH2A.X accumulation and apoptosis. Proteomic analysis of HIPK2-associated proteins using liquid chromatography-tandem mass spectrometry identified heterochromatin protein 1γ (HP1γ) as a novel target for HIPK2. Immunoprecipitation experiments with HCT116 cells expressing FLAG-tagged HIPK2 and one of the HA-tagged HP1 family members demonstrated that HIPK2 specifically associated with HP1γ, but not with HP1α or HP1β, through its chromo-shadow domain. Mutation of the HP1box motif (883-PTVSV-887) within HIPK2 abolished the association. HP1γ knockdown also enhanced accumulation of γH2A.X and apoptosis after sublethal UV-C irradiation. In vitro kinase assay demonstrated an HP1γ-phosphorylating activity of HIPK2. Sublethal UV-C irradiation phosphorylated HP1γ. This phosphorylation was absent in endogenous HIPK2-silenced cells with HIPK2 3'UTR siRNA. Overexpression of FLAG-HIPK2, but not the HP1box-mutated or kinase-dead HIPK2 mutant, in the HIPK2-silenced cells increased HP1γ binding to trimethylated (Lys9) histone H3 (H3K9me3), rescued the UV-C-induced phosphorylation of HP1γ, triggered release of HP1γ from histone H3K9me3 and suppressed γH2A.X accumulation. Our results suggest that HIPK2-dependent

  14. New Criteria to Assess Seismic and Rock Burst Hazard in Coal Mines / Nowe Kryteria Dla Oceny Zagrożenia Sejsmicznego I Tąpaniami W Kopalniach Węgla Kamiennego

    NASA Astrophysics Data System (ADS)

    Mutke, Grzegorz; Dubiński, Józef; Lurka, Adam

    2015-09-01

    The paper presents new criteria of seismic and rock burst hazard assessment in Polish hard coal mines where longwall mining system is common practice. The presented criteria are based on the results of continuous recording of seismic events and analysis of selected seismological parameters: spatial location of seismic event in relation to mining workings, seismic energy, seismic energy release per unit coal face advance, b-value of Gutenberg-Richter law, seismic energy index EI, seismic moment M0, weighted value of peak particle velocity PPVW. These parameters are determined in a moving daily time windows or time windows with fixed number of seismic tremors. Time changes of these parameters are then compared with mean value estimated in the analyzed area. This is the basis to indicate the zones of high seismic and rock burst hazard in specific moment in time during mining process. Additionally, the zones of high seismic and rock burst hazard are determined by utilization of passive seismic tomography method. All the calculated seismic parameters in moving time windows are used to quantify seismic and rock burst hazard by four level scales. In practice, assessment of seismic and rock burst hazard is used to make daily decision about using rock burst prevention activities and correction of further exploitation of monitored coal panel. Zagrożenie sejsmiczne i związane z nim genetycznie zagrożenie tąpnięciem w dalszym ciągu należą do najgroźniejszych zagrożeń naturalnych występujących w polskich kopalniach węgla kamiennego. W ostatnich latach w kopalniach Górnośląskiego Zagłębia Węglowego (GZW) rocznie rejestrowano 1000÷1500 wstrząsów o energii sejsmicznej Es ≥ 1·105J (magnituda lokalna ML ≥ 1.7), a najsilniejsze z nich osiągały energię Es = 4 ·109J (ML = 4.1). W latach 1991-2010 odnotowano w GZW 101 tąpnięć, z których około 66% miało miejsce w wyrobiskach chodnikowych, powodując ich uszkodzenia lub całkowite zniszczenie, a w

  15. Possible undercompensation effect in the Kondo insulator (Yb,Tm)B12

    NASA Astrophysics Data System (ADS)

    Alekseev, P. A.; Nemkovski, K. S.; Mignot, J.-M.; Clementyev, E. S.; Ivanov, A. S.; Rols, S.; Bewley, R. I.; Filipov, V. B.; Shitsevalova, N. Yu.

    2014-03-01

    The effects of Tm substitution on the dynamical magnetic response of Yb1-xTmxB12 (x=0, 0.08, 0.15, and 0.75) and Lu0.92Tm0.08B12 compounds have been studied using time-of-flight inelastic neutron scattering. Major changes were observed in the spectral structure and temperature evolution of the Yb contribution to the inelastic response for a rather low content of magnetic Tm ions. A sizable influence of the RB12 host (YbB12, as compared to LuB12 or pure TmB12) on the crystal-field splitting of the Tm3+ ion is also reported. The results point to a specific effect of impurities carrying a magnetic moment (Tm, as compared to Lu or Zr) in a Kondo insulator, which is thought to reflect the "undercompensation" of Yb magnetic moments, originally Kondo screened in pure YbB12. A parallel is made with the strong effect of Tm substitution on the temperature dependence of the Seebeck coefficient in Yb1-xTmxB12, which was reported previously.

  16. Seventh international workshop on the fragile X and X-linked mental retardation

    SciTech Connect

    Tranebjaerg, L.; Lubs, H.A.; Borghgraef, M.; Fryns, J.P.

    1996-07-12

    The Seventh International Workshop on the Fragile X and X-linked Mental Retardation was held at the University of Tromso in Norway on August 2-5, 1995. Approximately 120 participants from 20 countries attended the Workshop. By special invitation Dr. Felix de la Cruz, who initiated the first international Workshop on fragile X, attended this Workshop. For the first time, the workshop took place in Scandinavia and was hosted by Lisbeth Tranebjaerg and Herbert Lubs. For most participants this Workshop, held at the northernmost university in the world, presented a unique opportunity to visit this exotic place. Between sessions, the participants had a chance to experience 24 hours of daylight, codfishing, and extreme weather situations with excessive amounts of rain as well as spectacular changes in the light and rainbows. The format of the Workshop was a combination of platform presentations and poster presentations. In contrast to previous meetings, the Workshop opened with syndromal and non-syndromal X-linked mental retardation in order to allow time for discussion. 34 refs., 1 fig.

  17. Metabolicsyndrome in youngpatients.

    PubMed

    Otto-Buczkowska, Ewa; Dryżałowski, Marek

    2015-12-15

    Zespół metaboliczny jest poważnym problemem w populacji dzieci i młodzieży. Predyspozycje genetyczne oraz czynniki środowiskowe, jak np. brak aktywności fizycznej i zwiększona podaż kalorii, są odpowiedzialne za podatność na rozwój zespołu metabolicznego. Badany jest również wpływ immunologicznych mechanizmów otyłości i zespołu metabolicznego, włączając w nie rolę limfocytów T regulatorowych. Zespół metaboliczny określa się jako zbiór czynników (obejmujących otyłość brzuszną, dyslipidemię, insulinooporność, nietolerancję glukozy lub cukrzycę oraz nadciśnienie tętnicze), które zwiększają ryzyko przyspieszonego rozwoju schorzeń układu sercowo-naczyniowego oraz innych konsekwencji zdrowotnych.

  18. System and method of self-properties for an autonomous and automatic computer environment

    NASA Technical Reports Server (NTRS)

    Hinchey, Michael G. (Inventor); Sterritt, Roy (Inventor)

    2010-01-01

    Systems, methods and apparatus are provided through which in some embodiments self health/urgency data and environment health/urgency data may be transmitted externally from an autonomic element. Other embodiments may include transmitting the self health/urgency data and environment health/urgency data together on a regular basis similar to the lub-dub of a heartbeat. Yet other embodiments may include a method for managing a system based on the functioning state and operating status of the system, wherein the method may include processing received signals from the system indicative of the functioning state and the operating status to obtain an analysis of the condition of the system, generating one or more stay alive signals based on the functioning status and the operating state of the system, transmitting the stay-alive signal, transmitting self health/urgency data, and transmitting environment health/urgency data. Still other embodiments may include an autonomic element that includes a self monitor, a self adjuster, an environment monitor, and an autonomic manager.

  19. Changes in homologous recombination frequency in Arabidopsis thaliana plants exposed to stress depend on time of exposure during development and on duration of stress exposure.

    PubMed

    Rahavi, Seyed Mohammad Reza; Kovalchuk, Igor

    2013-10-01

    In the past, we showed that exposure to abiotic and biotic stresses changes the homologous recombination frequency (HRF) in somatic tissue and in the progeny. In current work we planned to answer the following question: do stress intensity/duration and time during exposure influence changes in somatic HRF and transgenerational changes in HRF? Here, we tested the effects of exposure to UV-C, cold and heat on HRF at 7, 14, 21 and 28 days post germination (dpg). We found that exposure at 14 and 21 dpg resulted in a higher increase in HRF as compared to exposure at 7 dpg; longer exposure to UV-C resulted in a higher frequency of HR, whereas prolonged exposure to cold or heat, especially at later developmental stages, had almost no effect on somatic HRF. Exposure at 7 dpg had a positive effect on somatic growth of plants; plants exposed to stress at this age had larger leaves. The analysis of HRF in the progeny showed that the progeny of plants exposed to stress at 7 dpg had an increase in somatic HRF and showed larger sizes of recombination spots on leaves. The progeny of plants exposed to UV-C at 7 dpg and the progeny of plants exposed to cold or heat at 28 dpg had larger leaves as compared to control plants. To summarize, our experiments showed that changes in somatic and transgenerational HRF depend on the type of stress plants are exposed to, time of exposure during development and the duration of exposure.

  20. Ceramide synthase-dependent ceramide generation and programmed cell death: involvement of salvage pathway in regulating postmitochondrial events.

    PubMed

    Mullen, Thomas D; Jenkins, Russell W; Clarke, Christopher J; Bielawski, Jacek; Hannun, Yusuf A; Obeid, Lina M

    2011-05-06

    The sphingolipid ceramide has been widely implicated in the regulation of programmed cell death or apoptosis. The accumulation of ceramide has been demonstrated in a wide variety of experimental models of apoptosis and in response to a myriad of stimuli and cellular stresses. However, the detailed mechanisms of its generation and regulatory role during apoptosis are poorly understood. We sought to determine the regulation and roles of ceramide production in a model of ultraviolet light-C (UV-C)-induced programmed cell death. We found that UV-C irradiation induces the accumulation of multiple sphingolipid species including ceramide, dihydroceramide, sphingomyelin, and hexosylceramide. Late ceramide generation was also found to be regulated by Bcl-xL, Bak, and caspases. Surprisingly, inhibition of de novo synthesis using myriocin or fumonisin B1 resulted in decreased overall cellular ceramide levels basally and in response to UV-C, but only fumonisin B1 inhibited cell death, suggesting the presence of a ceramide synthase (CerS)-dependent, sphingosine-derived pool of ceramide in regulating programmed cell death. We found that this pool did not regulate the mitochondrial pathway, but it did partially regulate activation of caspase-7 and, more importantly, was necessary for late plasma membrane permeabilization. Attempting to identify the CerS responsible for this effect, we found that combined knockdown of CerS5 and CerS6 was able to decrease long-chain ceramide accumulation and plasma membrane permeabilization. These data identify a novel role for CerS and the sphingosine salvage pathway in regulating membrane permeability in the execution phase of programmed cell death.

  1. Ceramide Synthase-dependent Ceramide Generation and Programmed Cell Death

    PubMed Central

    Mullen, Thomas D.; Jenkins, Russell W.; Clarke, Christopher J.; Bielawski, Jacek; Hannun, Yusuf A.; Obeid, Lina M.

    2011-01-01

    The sphingolipid ceramide has been widely implicated in the regulation of programmed cell death or apoptosis. The accumulation of ceramide has been demonstrated in a wide variety of experimental models of apoptosis and in response to a myriad of stimuli and cellular stresses. However, the detailed mechanisms of its generation and regulatory role during apoptosis are poorly understood. We sought to determine the regulation and roles of ceramide production in a model of ultraviolet light-C (UV-C)-induced programmed cell death. We found that UV-C irradiation induces the accumulation of multiple sphingolipid species including ceramide, dihydroceramide, sphingomyelin, and hexosylceramide. Late ceramide generation was also found to be regulated by Bcl-xL, Bak, and caspases. Surprisingly, inhibition of de novo synthesis using myriocin or fumonisin B1 resulted in decreased overall cellular ceramide levels basally and in response to UV-C, but only fumonisin B1 inhibited cell death, suggesting the presence of a ceramide synthase (CerS)-dependent, sphingosine-derived pool of ceramide in regulating programmed cell death. We found that this pool did not regulate the mitochondrial pathway, but it did partially regulate activation of caspase-7 and, more importantly, was necessary for late plasma membrane permeabilization. Attempting to identify the CerS responsible for this effect, we found that combined knockdown of CerS5 and CerS6 was able to decrease long-chain ceramide accumulation and plasma membrane permeabilization. These data identify a novel role for CerS and the sphingosine salvage pathway in regulating membrane permeability in the execution phase of programmed cell death. PMID:21388949

  2. Effects of Ultraviolet Radiation on the Gram-positive marine bacterium Microbacterium maritypicum.

    PubMed

    Williams, Patrick D; Eichstadt, Shaundra L; Kokjohn, Tyler A; Martin, Eugene L

    2007-07-01

    Although extensive information is available on the effect ultraviolet (UV) radiation has on Gram-negative marine bacteria, there is a scarcity of data concerning UV radiation and Gram-positive marine bacteria. The focus of this paper is on Microbacterium maritypicum, with the Gram-negative Vibrio natriegens being used as a standard of comparison. M. maritypicum exhibited growth over a NaCl range of 0-1000 mM: , with optimum growth occurring between 0 and 400 mM: NaCl. In contrast, V. natriegens grew over a NaCl span of 250-1000 mM: , with best growth being observed between 250 and 600 mM: NaCl. UV radiation experiments were done using the medium with 250 mM: NaCl. For solar (UV-A and B) radiation and log-phase cells, M. maritypicum was determined to be three times more resistant than V. natriegens. For germicidal (UV-C) radiation, the pattern of resistance of the log-phase cells to the lethal effects of the radiation was even more pronounced, with the Gram-positive bacterium being more than 12 to 13 times more resistant. Similar data to the solar and germicidal log-phase UV kill curves were obtained for stationary-phase cells of both organisms. Photoreactivation was observed for both types of cells exposed to UV-C but none for cells treated with UV-A and B. When log phase cells of M.maritypicum were grown at 0.0 and 0.6 M: NaCl and exposed to UV-C radiation, no difference in survivorship patterns was noted from that of 0.25 M: NaCl grown cells. Although this study has only focused on two marine bacteria, our results indicate that the Gram-positive M. maritypicum could have a built-in advantage for survival in some marine ecosystems.

  3. Evaluating the Effect of Expressing a Peanut Resveratrol Synthase Gene in Rice

    PubMed Central

    Li, Zhen; Wang, Qingguo; Yao, Fangyin; Yang, Lianqun; Pan, Jiaowen; Liu, Wei

    2015-01-01

    Resveratrol (Res) is a type of natural plant stilbenes and phytoalexins that only exists in a few plant species. Studies have shown that the Res could be biosynthesized and accumulated within plants, once the complete metabolic pathway and related enzymes, such as the key enzyme resveratrol synthase (RS), existed. In this study, a RS gene named PNRS1 was cloned from the peanut, and the activity was confirmed in E. coli. Using transgenic approach, the PNRS1 transgenic rice was obtained. In T3 generation, the Res production and accumulation were further detected by HPLC. Our data revealed that compared to the wild type rice which trans-resveratrol was undetectable, in transgenic rice, the trans-resveratrol could be synthesized and achieved up to 0.697 μg/g FW in seedlings and 3.053 μg/g DW in seeds. Furthermore, the concentration of trans-resveratrol in transgenic rice seedlings could be induced up to eight or four-fold higher by ultraviolet (UV-C) or dark, respectively. Simultaneously, the endogenous increased of Res also showed the advantages in protecting the host plant from UV-C caused damage or dark-induced senescence. Our data indicated that Res was involved in host-defense responses against environmental stresses in transgenic rice. Here the results describes the processes of a peanut resveratrol synthase gene transformed into rice, and the detection of trans-resveratrol in transgenic rice, and the role of trans-resveratrol as a phytoalexin in transgenic rice when treated by UV-C and dark. These findings present new outcomes of transgenic approaches for functional genes and their corresponding physiological functions, and shed some light on broadening available resources of Res, nutritional improvement of crops, and new variety cultivation by genetic engineering. PMID:26302213

  4. The Effect of Photon Source on Heterogeneous Photocatalytic Oxidation of Ethanol by a Silica-Titania Composite

    NASA Technical Reports Server (NTRS)

    Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Mazyck, David W.

    2011-01-01

    The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp ((gamma)max=365 nm) at its maximum light intensity or a UV-C germicidal lamp ((gamma)max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM/s) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 (mu)mol/photons). UV-C irradiation also led to decreased intermediate concentration in the effluent . compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.

  5. Egr1 Target Genes That Regulate Growth/Survival of Prostate Cells

    DTIC Science & Technology

    2005-03-01

    indicating that, in the absence of Egrl, both p300 Apigenin or DRB (inhibitors of CK2) before UV-C, show- and CBP genes are expressed at higher levels...he C K2 i nhibi- UO f W0W we C5P + -4DRS + -OMtors, ORB (50 .tMv), or Apigenin (50 l.LM) for ŖPI-Egri 30 min immediately following exposure to UV...cycloheximide, genestein, tyrphostin-AG1 112, H-7 dihydrochloride, sion of the disease by its constitutive expression. This apigenin and 5,6-dichloro

  6. Sensitivity of human cells expressing low-fidelity or weak-catalytic-activity variants of DNA polymerase ζ to genotoxic stresses.

    PubMed

    Suzuki, Tetsuya; Grúz, Petr; Honma, Masamitsu; Adachi, Noritaka; Nohmi, Takehiko

    2016-09-01

    Translesion DNA polymerases (TLS pols) play critical roles in defense mechanisms against genotoxic agents. The defects or mutations of TLS pols are predicted to result in hypersensitivity of cells to environmental mutagens. In this study, human cells expressing DNA polymerase ζ (Pol ζ) variants with low fidelity or weak catalytic activity have been established with Nalm-6-MSH+ cells and their sensitivity to mutagenicity and cytotoxicity of benzo[a]pyrene diol epoxide (BPDE) and ultraviolet-C light (UV-C) was examined. The low-fidelity mutants were engineered by knocking-in DNA sequences that direct changes of leucine 2618 to either phenylalanine (L2618F) or methionine (L2618M) of Pol ζ. The weak-catalytic-activity mutants were generated by knocking-in DNA sequences that direct changes of either tyrosine 2779 to phenylalanine (Y2779F) or aspartate 2781 to asparagine (D2781N). In addition, a +1 frameshift mutation, i.e., CCC to CCCC, was introduced in the coding region of the TK1 gene to measure the mutant frequencies. Doubling time and spontaneous TK mutant frequencies of the established cell lines were similar to those of the wild-type cells. The low-fidelity mutants displayed, however, higher sensitivity to the mutagenicity of BPDE and UV-C than the wild-type cells although their cytotoxic sensitivity was not changed. In contrast, the weak-catalytic-activity mutants were more sensitive to the cytotoxicity of BPDE and UV-C than the wild-type cells, and displayed much higher sensitivity to the clastogenicity of BPDE than the wild-type cells in an in vitro micronucleus assay. These results indicate that human Pol ζ is involved in TLS across DNA lesions induced by BPDE and UV-C and also that the TLS plays important roles in induction of mutations, clastogenicity and in cellular survival of the damaged human cells. Similarities and differences in in vivo roles of yeast and human Pol ζ in genome integrity are discussed.

  7. Chemical sporulation and germination: cytoprotective nanocoating of individual mammalian cells with a degradable tannic acid-FeIII complex.

    PubMed

    Lee, Juno; Cho, Hyeoncheol; Choi, Jinsu; Kim, Doyeon; Hong, Daewha; Park, Ji Hun; Yang, Sung Ho; Choi, Insung S

    2015-12-07

    Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-Fe(III) nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-Fe(III) nanocoat, mimicking the sporulation and germination processes found in nature.

  8. Effect of UV and UV/H2O2 in the presence of chloramines on NDMA formation potential of tramadol.

    PubMed

    Radjenovic, Jelena; Farré, Maria José; Gernjak, Wolfgang

    2012-08-07

    This study evaluates the effect of UV-C and UV-C/H(2)O(2) in the presence of chloramines on the N-nitrosodimethylamine formation potential (NDMA FP) of tramadol as a model precursor. The experiments were performed at high initial concentrations of TMDL (i.e., 20 mg/L) in order to elucidate the structures of TMDL byproducts. Twenty-four byproducts were identified in UV-C, UV-C/monochloramine, and UV/H(2)O(2)/monochloramine oxidation of tramadol using MS(3) capabilities of a hybrid quadrupole-linear ion trap mass spectrometer, combined with online hydrogen/deuterium (H/D) exchange experiments. Oxidative cleavage of methoxy and methoxybenzene moiety, O-demethylation, hydroxylation, and cyclohexane ring-opening were identified as major reaction mechanisms of tramadol in UV oxidation. Addition of monochloramine decreased the degradation rates of tramadol and its byproducts and yielded several monochlorinated derivatives. The oxidation rates were significantly enhanced in the presence of H(2)O(2), and byproducts of oxidative benzene ring-opening were detected. The majority of the identified byproducts are likely to have a higher NDMA FP than the parent compound due to a reduced steric hindrance and/or insertion of electron-donating hydroxyl groups in the N,N-dimethylamine side chain. This was confirmed by the results of NDMA FP tests, which showed that the formation of NDMA was enhanced up to four times depending on the process conditions in UV alone and in UV and UV/H(2)O(2) in the presence of monochloramine. Prolonged oxidation by hydroxyl radicals in UV/H(2)O(2)/monochloramine process mineralized some of the byproducts and slightly reduced the NDMA FP at the end of the treatment. The obtained degradation pathway of tramadol allowed the correlation of changes in NDMA FP during oxidation with its major oxidative transformation reactions. This manuscript demonstrates the significance of oxidation byproducts as NDMA precursors and emphasizes the need for their

  9. Preliminary Assessment McGhee - Tyson ANGB, McGhee - Tyson Municipal Airport, Knoxville, Tennessee

    DTIC Science & Technology

    1988-06-01

    Air Defense Command (ADC) was changed to theI Tactical Air Command (TAC). Having no previously qualified KC-97 aircrews or maintenance personnel...anticipated to cause death, disease, behavioral abnormalities, cancer , genetic mutation, physiological malfunctions (including malfunctions in reproduction...4 .e4 8 A @2~ ~~~~ 41 4) 104 3 4 - 4 1 4 1 4 41~~~ A0 Uv c 4 ( VI U~~ ~~~ ~~ H-0__ _ _ _ __ _ _ _ _ _ _ 01 ’-4 %0 J fo𔃾I (N 0 v~ -4 (N en OD N 0

  10. Comparative DNA damage and repair in echinoderm coelomocytes exposed to genotoxicants.

    PubMed

    El-Bibany, Ameena H; Bodnar, Andrea G; Reinardy, Helena C

    2014-01-01

    The capacity to withstand and repair DNA damage differs among species and plays a role in determining an organism's resistance to genotoxicity, life history, and susceptibility to disease. Environmental stressors that affect organisms at the genetic level are of particular concern in ecotoxicology due to the potential for chronic effects and trans-generational impacts on populations. Echinoderms are valuable organisms to study the relationship between DNA repair and resistance to genotoxic stress due to their history and use as ecotoxicological models, little evidence of senescence, and few reported cases of neoplasia. Coelomocytes (immune cells) have been proposed to serve as sensitive bioindicators of environmental stress and are often used to assess genotoxicity; however, little is known about how coelomocytes from different echinoderm species respond to genotoxic stress. In this study, DNA damage was assessed (by Fast Micromethod) in coelomocytes of four echinoderm species (sea urchins Lytechinus variegatus, Echinometra lucunter lucunter, and Tripneustes ventricosus, and a sea cucumber Isostichopus badionotus) after acute exposure to H2O2 (0-100 mM) and UV-C (0-9999 J/m2), and DNA repair was analyzed over a 24-hour period of recovery. Results show that coelomocytes from all four echinoderm species have the capacity to repair both UV-C and H2O2-induced DNA damage; however, there were differences in repair capacity between species. At 24 hours following exposure to the highest concentration of H2O2 (100 mM) and highest dose of UV-C (9999 J/m2) cell viability remained high (>94.6 ± 1.2%) but DNA repair ranged from 18.2 ± 9.2% to 70.8 ± 16.0% for H2O2 and 8.4 ± 3.2% to 79.8 ± 9.0% for UV-C exposure. Species-specific differences in genotoxic susceptibility and capacity for DNA repair are important to consider when evaluating ecogenotoxicological model organisms and assessing overall impacts of genotoxicants in the environment.

  11. Comparative DNA Damage and Repair in Echinoderm Coelomocytes Exposed to Genotoxicants

    PubMed Central

    El-Bibany, Ameena H.; Bodnar, Andrea G.; Reinardy, Helena C.

    2014-01-01

    The capacity to withstand and repair DNA damage differs among species and plays a role in determining an organism's resistance to genotoxicity, life history, and susceptibility to disease. Environmental stressors that affect organisms at the genetic level are of particular concern in ecotoxicology due to the potential for chronic effects and trans-generational impacts on populations. Echinoderms are valuable organisms to study the relationship between DNA repair and resistance to genotoxic stress due to their history and use as ecotoxicological models, little evidence of senescence, and few reported cases of neoplasia. Coelomocytes (immune cells) have been proposed to serve as sensitive bioindicators of environmental stress and are often used to assess genotoxicity; however, little is known about how coelomocytes from different echinoderm species respond to genotoxic stress. In this study, DNA damage was assessed (by Fast Micromethod) in coelomocytes of four echinoderm species (sea urchins Lytechinus variegatus, Echinometra lucunter lucunter, and Tripneustes ventricosus, and a sea cucumber Isostichopus badionotus) after acute exposure to H2O2 (0–100 mM) and UV-C (0–9999 J/m2), and DNA repair was analyzed over a 24-hour period of recovery. Results show that coelomocytes from all four echinoderm species have the capacity to repair both UV-C and H2O2-induced DNA damage; however, there were differences in repair capacity between species. At 24 hours following exposure to the highest concentration of H2O2 (100 mM) and highest dose of UV-C (9999 J/m2) cell viability remained high (>94.6±1.2%) but DNA repair ranged from 18.2±9.2% to 70.8±16.0% for H2O2 and 8.4±3.2% to 79.8±9.0% for UV-C exposure. Species-specific differences in genotoxic susceptibility and capacity for DNA repair are important to consider when evaluating ecogenotoxicological model organisms and assessing overall impacts of genotoxicants in the environment. PMID:25229547

  12. Irregular antibodies in no hemolytic autoimmune diseases are able to induce erythrophagocytosis.

    PubMed

    López-Díaz, Paola Ester; Ruiz-Olivera, María Del Rocío; Hernández-Osorio, Luis Alberto; Vargas-Arzola, Jaime; Valle-Jiménez, Xareni; Aguilar-Ruiz, Sergio Roberto; Torres-Aguilar, Honorio

    2016-08-25

    Irregular antibodies are produced by alloimmunization because of pregnancies or blood transfusions. They are called "irregular" due to target erythrocyte antigens from "rare blood systems," those different from the ABO system. Irregular antibodies have been widely investigated in immunohematology since their presence in blood donors may lead to difficulties in blood typing and in blood cross-matching, or to induce hemolytic transfusion reactions. Nevertheless, their incidence and participation in the physiopathology of autoimmune diseases have not been thoroughly studied. In this work, we analyzed the presence and pro-hemolytic capabilities of irregular antibodies in patients with different autoimmune diseases lacking signs of hemolytic anemia, in comparison with healthy multiparous women. Five of 141 autoimmune patients (3.5 %) and two of 77 multiparous women (2.6 %) were positive. Although frequency was relatively low and similar in both populations, the targeted antigens were Kell (k, Kp(b), Js(b)) and Luth (Lu(b)) in multiparous women, and the same plus Duffy (Fy(a)), Kidd (Jk(a)) and MNS (M, s) in autoimmune patients. Irregular antibodies from autoimmune patients did not induce complement-mediated hemolysis (intravascular), but they were able to induce macrophages-mediated phagocytosis (extravascular hemolysis) in vitro. It is the first approach exploring the presence of irregular antibodies associated with the loss of immune tolerance and demonstrating their hemolytic potential in autoimmune patients without hemolytic manifestations. The presence of irregular antibodies targeted to Duffy (Fya), Kidd (Jka) and MNS (M, s) antigens only in autoimmune patients suggests a loss of immune tolerance to these erythrocyte antigens.

  13. Frequency, patterns, and preferences of lubricant use during anal intercourse within male sexual partnerships in Lima, Peru: implications for a rectal microbicide HIV prevention intervention.

    PubMed

    Clark, Jesse L; Salvatierra, Hector J; Segura, Eddy R; Salazar, Ximena; Konda, Kelika; Galea, Jerome; Klausner, Jeffrey D; Coates, Thomas J; Caceres, Carlos F

    2013-01-01

    Understanding current practices of lubricant use during anal intercourse can help to assess the contexts for the introduction of topical rectal microbicides as an HIV prevention tool for men who have sex with men (MSM). We used quantitative and qualitative methods to assess: current patterns of lubricant use; preferred characteristics of commercial lubricant formulations; and social and behavioral contexts of lubricant use within male sexual partnerships in Lima, Peru. Between 2007 and 2008, we conducted a quantitative behavioral survey with 547 MSM followed by qualitative individual and group interviews with 36 MSM from Lima, Peru. Approximately half of all participants in the quantitative survey (50.3%) reported using commercial lubricant during intercourse occasionally or consistently during the preceding two months, with lack of availability at the time of intercourse the most commonly reported reason for non-use. No clear preferences regarding the color, smell, taste, or viscosity of commercial lubricants were identified, and all participants who reported using a commercial lubricant used the same product ("Love-Lub"). In the qualitative analysis, participants characterized lubricant use as a sexual practice consistently controlled by the receptive partner, who typically obtained and applied lubricant independently, with or without the consent of the insertive partner. Quantitative findings supported this differential pattern of lubricant use, with men who reported sexual identities or roles consistent with receptive anal intercourse, including unprotected receptive intercourse, more likely to report lubricant use than MSM who claimed an exclusively insertive sexual role. Given the social, behavioral, and biological factors contributing to increased vulnerability for HIV and STI acquisition by the receptive partner in anal intercourse, delivery of a topical rectal microbicide as a lubricant formulation could provide an important HIV prevention resource for at

  14. Role of gluten-free diet in pathogenesis of type 1 diabetes - what new?

    PubMed

    Chwalba, Artur; Otto-Buczkowska, Ewa

    2015-01-01

    W ostatnich dekadach związek pomiędzy występowaniem celiakii a innymi autoimmunologicznymi schorzeniami, takimi jak autoimmunologiczne schorzenia tarczycy czy cukrzyca typu 1, został ustalony w wielu badaniach i jest do dziś przedmiotem klinicznych i naukowych obserwacji na całym świecie. Cukrzyca typu 1 (T1DM) i choroba trzewna (CD) mają podobne tło genetyczne związane z genotypem HLA-DQ2 / DQ8. Współzależność pomiędzy spożywaniem glutenu a późniejszym rozwojem cukrzycy typu 1 została wykazana w badaniach u ludzi i u zwierząt doświadczalnych. Badania te dowiodły, że dieta bez zawartości glutenu obniża poziom receptora NKG2D i ekspresje jego ligandów u myszy (GF). Tak więc gluten może rzutować na rozwój cukrzycy poprzez wpływ na modyfikację wzoru stosunku cytokiny/chemokiny, powodującą profil zapalny. Potwierdza to ważną rolę spożycia glutenu w patogenezie cukrzycy typu 1. Uzasadnione jest prowadzenie dalszych badań w celu wyjaśnienia, czy dieta bezglutenowa może zapobiec chorobie u osób predysponowanych lub czy może być zastosowana u pacjentów ze świeżo rozpoznaną cukrzycą w celu zatrzymania jej rozwoju. Te obserwacje mogę być ważne w pierwotnej prewencji cukrzycy.

  15. Dynamics of the MAP IOP 15 severe Mistral event: Observations and high-resolution numerical simulations

    NASA Astrophysics Data System (ADS)

    Guénard, V.; Drobinski, P.; Caccia, J. L.; Tedeschi, G.; Currier, P.

    2006-04-01

    This paper investigates the fundamental processes involved in a severe Mistral event that occurred during the Mesoscale Alpine Program (from 6 to 9 November 1999). The Mistral refers to a violent north/north-westerly wind blowing in south-eastern France from the Rhône valley to the French Riviera. The study is based on measurements from radiosoundings launched from Lyon and Nîmes and from two UHF wind profilers located near Marseille and Toulon allowing a good description of the flow in the complex terrain formed by the south-western Alps. Observational results are compared with RAMS non-hydrostatic numerical simulations performed with 27 km, 9 km and 3 km nested grids. The numerical simulations capture the flow complexity both upstream of the Alps and in the coastal area affected by the Mistral. They correctly reproduce horizontal wind speeds and directions, vertical velocities, virtual potential temperature and relative humidity documented by the observational network. The simulations are used to point out the main dynamical processes generating the Mistral. It is found that flow splitting around the Alps and around the isolated peaks bordering the south-eastern part of the Rhône valley (Mont Ventoux 1909 m, Massif du Lubéron 1425 m) induces the low-level jet observed near Marseille that lasts for 36 hours. The high-resolution simulation indicates that the transient low-level jet lasting for only 9 hours observed at Toulon is due to a gravity wave breaking over local topography (the Sainte Baume 1147 m) where hydraulic jumps are involved. A mountain wake with two opposite-sign potential-vorticity banners is generated. The mesoscale wake explains the westward progression of the large-scale Alpine wake.

  16. From Columbus to Columbia

    NASA Astrophysics Data System (ADS)

    Morain, Stanley A.

    On the eve of Christopher Columbus's historic voyage to the New World, the international community of remote sensing and mapping sciences is poised to lead a new, environmentally conscious world into the 21st century. Developments in remote sensing and GIS technology during the past 25 years have paved the way for a modern round of earth exploration that could well equal in lasting importance the geographic achievement of Columbus, 500 years ago. Human experience has evolved from land-lubbing to sea-faring, air-faring and now space-faring so that in future all four modes will be used to enhacce our understanding of earth systems. Columbus "dead reckoned" his place into history by sailing the southern arm of the Atlantic Gyre westward to the Bahamas. For reasons beyond his knowledge, he was "lost" almost from the moment he departed; and to this day, his landfall is placed at several islands between Grand Turk at latitude 21.5°N and San Salvador at 24°N. His headings, nautical speeds, and drift are all subjects of controversy. Today, with global positioning systems, scientists and entrepreneurs can triangulate with considerable accuracy almost any point on the earth's surface, day or night; and, with a fourth satellite, can determine elevation. The same satellite constellation can monitor the speeds and headings of land, sea, and air transportation carriers for the benefit of all international commerce - a knowledge that would have been the envy of Spain's Admiral of the Ocean Seas throughout his search for spices, souls, and gold. We can only imagine what he and his captains might have given for a nightly satellite weather report, let alone images by which to navigate.

  17. Limit Analysis of Geometrically Hardening Composite Steel-Concrete Systems / Stany Graniczne Geometrycznie Wzmacniających Się Konstrukcji Zespolonych

    NASA Astrophysics Data System (ADS)

    Alawdin, Piotr; Urbańska, Krystyna

    2015-03-01

    The paper considers some results of creating load-carrying composite systems that have uprated strength, rigidity and safety, and therefore are called geometrically (self-) hardening systems. The optimization mathematic models of structures as discrete mechanical systems withstanding dead load, monotonic or low cyclic static and kinematic actions are proposed. To find limit parameters of these actions the extreme energetic principle is suggested what result in the bilevel mathematic programming problem statement. The limit parameters of load actions are found on the first level of optimization. On the second level the power of the constant load with equilibrium preloading is maximized and/or system cost is minimized. The examples of using the proposed methods are presented and geometrically hardening composite steel-concrete system are taken into account. W pracy przedstawiono sposoby projektowania konstrukcji, które ze względu na swoją geometrię oraz topologię posiadają podwyższoną nośność, sztywność i bezpieczeństwo. Systemy takie nazwano geometrycznie (samo-) wzmacniającymi się. Zaproponowano optymalizacyjne modele matematyczne konstrukcji jako dyskretne systemy mechaniczne będące pod obciążeniem stałym, zmiennym monotoniczne lub niskocyklowym, statycznym lub kinematycznym. Dla znalezienia granicznych parametrów obciążeń wprowadzona została ekstremalna zasada energetyczna, przedstawiona jako problem dwupoziomowego programowania matematycznego. Graniczne parametry obciążeń szukane są na pierwszym poziomie optymalizacji. Na drugim poziomie minimalizowany jest koszt systemu i/lub maksymalizowana jest moc stałego równoważącego obciążenia z dociążeniem. Ponadto w pracy przeanalizowano numerycznie i analitycznie zachowanie konstrukcji geometrycznie wzmacniających się na przykładzie konstrukcji zespolonych stalowobetonowych. Pierwszy przykład dotyczy konstrukcji belkowo-prętowej z podciągiem, belkę stanowi stalowy dwuteownik

  18. Environmental stress enhances biosynthesis of flavor precursors, S-3-(hexan-1-ol)-glutathione and S-3-(hexan-1-ol)-L-cysteine, in grapevine through glutathione S-transferase activation

    PubMed Central

    Kobayashi, Hironori; Takase, Hideki; Suzuki, Yumiko; Tanzawa, Fumiko; Takata, Ryoji; Fujita, Keiko; Kohno, Minako; Mochizuki, Mai; Suzuki, Shunji; Konno, Tomonori

    2011-01-01

    The biosynthesis of S-(3-hexan-1-ol)-glutathione (3MH-S-glut) and S-(3-hexan-l-ol)-L-cysteine (3MH-S-cys), which act as flavour precursors in wines, in Vitis vinifera grapes exposed to various environmental stress conditions is reported here. Ultraviolet (UV-C) irradiation, water deficit, and biological stimulation up-regulated 3MH-S-glut and 3MH-S-cys biosynthesis in grape leaves. 3MH-S-glut and 3MH-S-cys contents in grape berries were increased by cold shock, heat shock, UV-C irradiation, and biological stimulation. The results suggest that environmental stress enhances the biosynthesis of both flavour precursors in grapevine. The transcription of VvGST1, VvGST3, VvGST4, and GGT in grapevine exposed to the stress conditions was increased markedly compared with that in control grapevine. Also, UV irradiation increased GST (glutathione S-transferase) and GGT (γ-glutamyl transferase) enzyme activities in grape berries. Recombinant VvGST3 and VvGST4, but not VvGST1, mediated the synthesis of 3MH-S-glut from reduced glutathione and trans-2-hexenal in vitro. The enzymatic mediation of flavour precursor production is a novel function of plant GSTs and may result in the detoxification of damaged grape cells under stress conditions. PMID:21115666

  19. Selective role of intracellular chloride in the regulation of the intrinsic but not extrinsic pathway of apoptosis in Jurkat T-cells.

    PubMed

    Heimlich, Gerd; Cidlowski, John A

    2006-01-27

    Apoptosis is a genetic program for the removal of unwanted cells from an organism, which is distinct from necrosis by its characteristic volume loss or apoptotic volume decrease. This cell shrinkage is the result of ion redistribution that is crucial for both the activation and execution of apoptosis. Here we report that UV-C but not Fas ligand treatment results in a significant decrease in intracellular chloride that can be abolished by modulation of chloride flux using either the chloride channel inhibitor SITS or medium with a reduced chloride concentration. Accordingly, downstream events are diminished during UV-C-induced apoptosis following chloride flux modulation, whereas Fas ligand-induced apoptotic characteristics are not affected. Moreover, the activation of the mitogen-activated protein kinase signal transduction pathway early in the apoptotic signaling cascade was affected by chloride flux in Jurkat T-cells. Thus, an alteration of intracellular chloride plays an important role in the activation of signaling molecules upstream of the mitochondria, specifically impairing the intrinsic but not extrinsic apoptotic pathway.

  20. The tomato DWD motif-containing protein DDI1 interacts with the CUL4–DDB1-based ubiquitin ligase and plays a pivotal role in abiotic stress responses

    SciTech Connect

    Miao, Min; Zhu, Yunye; Qiao, Maiju; Tang, Xiaofeng; Zhao, Wei; Xiao, Fangming; Liu, Yongsheng

    2014-08-08

    Highlights: • We identify DDI1 as a DAMAGED DNA BINDING PROTEIN1 (DDB1)-interacting protein. • DDI1 interacts with the CUL4–DDB1-based ubiquitin ligase in the nucleus. • DDI1 plays a positive role in regulating abiotic stress response in tomato. - Abstract: CULLIN4(CUL4)–DAMAGED DNA BINDING PROTEIN1 (DDB1)-based ubiquitin ligase plays significant roles in multiple physiological processes via ubiquitination-mediated degradation of relevant target proteins. The DDB1–CUL4-associated factor (DCAF) acts as substrate receptor in the CUL4–DDB1 ubiquitin ligase complex and determines substrate specificity. In this study, we identified a tomato (Solanum lycopersicum) DDB1-interacting (DDI1) protein as a DCAF protein involved in response to abiotic stresses, including UV radiation, high salinity and osmotic stress. Co-immunoprecipitation and bimolecular fluorescence complementation assay indicated that DDI1 associates with CUL4–DDB1 in the nucleus. Quantitative RT-PCR analysis indicated the DDI1 gene is induced by salt, mannitol and UV-C treatment. Moreover, transgenic tomato plants with overexpression or knockdown of the DDI1 gene exhibited enhanced or attenuated tolerance to salt/mannitol/UV-C, respectively. Thus, our data suggest that DDI1 functions as a substrate receptor of the CUL4–DDB1 ubiquitin ligase, positively regulating abiotic stress response in tomato.

  1. Efficient charge carrier injection into sub-250 nm AlGaN multiple quantum well light emitting diodes

    SciTech Connect

    Mehnke, Frank Kuhn, Christian; Guttmann, Martin; Reich, Christoph; Kolbe, Tim; Rass, Jens; Wernicke, Tim; Kueller, Viola; Knauer, Arne; Lapeyrade, Mickael; Einfeldt, Sven; Weyers, Markus; Kneissl, Michael

    2014-08-04

    The design and Mg-doping profile of AlN/Al{sub 0.7}Ga{sub 0.3}N electron blocking heterostructures (EBH) for AlGaN multiple quantum well (MQW) light emitting diodes (LEDs) emitting below 250 nm was investigated. By inserting an AlN electron blocking layer (EBL) into the EBH, we were able to increase the quantum well emission power and significantly reduce long wavelength parasitic luminescence. Furthermore, electron leakage was suppressed by optimizing the thickness of the AlN EBL while still maintaining sufficient hole injection. Ultraviolet (UV)-C LEDs with very low parasitic luminescence (7% of total emission power) and external quantum efficiencies of 0.19% at 246 nm have been realized. This concept was applied to AlGaN MQW LEDs emitting between 235 nm and 263 nm with external quantum efficiencies ranging from 0.002% to 0.93%. After processing, we were able to demonstrate an UV-C LED emitting at 234 nm with 14.5 μW integrated optical output power and an external quantum efficiency of 0.012% at 18.2 A/cm{sup 2}.

  2. Chemical sporulation and germination: cytoprotective nanocoating of individual mammalian cells with a degradable tannic acid-FeIII complex

    NASA Astrophysics Data System (ADS)

    Lee, Juno; Cho, Hyeoncheol; Choi, Jinsu; Kim, Doyeon; Hong, Daewha; Park, Ji Hun; Yang, Sung Ho; Choi, Insung S.

    2015-11-01

    Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-FeIII nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-FeIII nanocoat, mimicking the sporulation and germination processes found in nature.Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-FeIII nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-FeIII nanocoat, mimicking the sporulation and germination processes found in nature. Electronic supplementary information (ESI) available: Experimental details, LSCM images, and SEM and TEM images. See DOI: 10.1039/c5nr05573c

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

    PubMed

    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.

  4. Selection of process conditions by risk assessment for apple juice pasteurization by UV-heat treatments at moderate temperatures.

    PubMed

    Gayán, E; Torres, J A; Alvarez, I; Condón, S

    2014-02-01

    The effect of bactericidal UV-C treatments (254 nm) on Escherichia coli O157:H7 suspended in apple juice increased synergistically with temperature up to a threshold value. The optimum UV-C treatment temperature was 55 °C, yielding a 58.9% synergistic lethal effect. Under these treatment conditions, the UV-heat (UV-H55 °C) lethal variability achieving 5-log reductions had a logistic distribution (α = 37.92, β = 1.10). Using this distribution, UV-H55 °C doses to achieve the required juice safety goal with 95, 99, and 99.9% confidence were 41.17, 42.97, and 46.00 J/ml, respectively, i.e., doses higher than the 37.58 J/ml estimated by a deterministic procedure. The public health impact of these results is that the larger UV-H55 °C dose required for achieving 5-log reductions with 95, 99, and 99.9% confidence would reduce the probability of hemolytic uremic syndrome in children by 76.3, 88.6, and 96.9%, respectively. This study illustrates the importance of including the effect of data variability when selecting operational parameters for novel and conventional preservation processes to achieve high food safety standards with the desired confidence level.

  5. Effects of sonication and ultraviolet-C treatment as a hurdle concept on quality attributes of Chokanan mango (Mangifera indica L.) juice.

    PubMed

    Santhirasegaram, Vicknesha; Razali, Zuliana; Somasundram, Chandran

    2015-04-01

    The growing demand for fresh-like food products has encouraged the development of hurdle technology of non-thermal processing. In this study, freshly squeezed Chokanan mango juice was treated by paired combinations of sonication (for 15 and 30 min at 25 ℃, 40 kHz frequency) and UV-C treatment (for 15 and 30 min at 25 ℃). Selected physicochemical properties, antioxidant activities, microbial inactivation and other quality parameters of combined treated juice were compared to conventional thermal treatment (at 90 ℃ for 60 s). After thermal and combined treatment, no significant changes occurred in physicochemical properties. A significant increase in extractability of carotenoids (15%), polyphenols (37%), flavonoids (35%) and enhancement in antioxidant capacity was observed after combined treatment. Thermal and combined treatment exhibited significant reduction in microbial load. Results obtained support the use of sonication and UV-C in a hurdle technology to improve the quality of Chokanan mango juice along with safety standards.

  6. PrimPol-deficient cells exhibit a pronounced G2 checkpoint response following UV damage

    PubMed Central

    Bailey, Laura J.; Bianchi, Julie; Hégarat, Nadia; Hochegger, Helfrid; Doherty, Aidan J.

    2016-01-01

    ABSTRACT PrimPol is a recently identified member of the archaeo-eukaryote primase (AEP) family of primase-polymerases. It has been shown that this mitochondrial and nuclear localized enzyme plays roles in the maintenance of both unperturbed replication fork progression and in the bypass of lesions after DNA damage. Here, we utilized an avian (DT40) knockout cell line to further study the consequences of loss of PrimPol (PrimPol−/−) on the downstream maintenance of cells after UV damage. We report that PrimPol−/− cells are more sensitive to UV-C irradiation in colony survival assays than Pol η-deficient cells. Although this increased UV sensitivity is not evident in cell viability assays, we show that this discrepancy is due to an enhanced checkpoint arrest after UV-C damage in the absence of PrimPol. PrimPol−/− arrested cells become stalled in G2, where they are protected from UV-induced cell death. Despite lacking an enzyme required for the bypass and maintenance of replication fork progression in the presence of UV damage, we show that PrimPol−/− cells actually have an advantage in the presence of a Chk1 inhibitor due to their slow progression through S-phase. PMID:26694751

  7. Ouabain-induced perturbations in intracellular ionic homeostasis regulate death receptor-mediated apoptosis.

    PubMed

    Panayiotidis, Mihalis I; Franco, Rodrigo; Bortner, Carl D; Cidlowski, John A

    2010-07-01

    Apoptosis is defined by specific morphological and biochemical characteristics including cell shrinkage (termed apoptotic volume decrease), a process that results from the regulation of ion channels and plasma membrane transporter activity. The Na(+)-K(+)-ATPase is the predominant pump that controls cell volume and plasma membrane potential in cells and alterations in its function have been suggested to be associated with apoptosis. We report here that the Na(+)-K(+)-ATPase inhibitor ouabain, potentiates apoptosis in the human lymphoma Jurkat cells exposed to Fas ligand (FasL) or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) but not other apoptotic agents such as H(2)O(2), thapsigargin or UV-C implicating a role for the Na(+)-K(+)-ATPase in death receptor-induced apoptosis. Interestingly, ouabain also potentiated perturbations in cell Ca(2+) homeostasis only in conjunction with the apoptotic inducer FasL but not TRAIL. Ouabain did not affect alterations in the intracellular Ca(2+) levels in response to H(2)O(2), thapsigargin or UV-C. FasL-induced alterations in Ca(2+) were not abolished in Ca(2+)-free medium but incubation of cells with BAPTA-AM inhibited both Ca(2+) perturbations and the ouabain-induced potentiation of FasL-induced apoptosis. Our data suggest that the impairment of the Na(+)-K(+)-ATPase activity during apoptosis is linked to perturbations in cell Ca(2+) homeostasis that modulate apoptosis induced by the activation of Fas by FasL.

  8. Electrochemical analysis of the UV treated bactericidal Ti6Al4V surfaces.

    PubMed

    Pacha-Olivenza, Miguel A; Gallardo-Moreno, Amparo M; Vadillo-Rodríguez, Virginia; González-Martín, M Luisa; Pérez-Giraldo, Ciro; Galván, Juan C

    2013-04-01

    This research investigates in detail the bactericidal effect exhibited by the surface of the biomaterial Ti6Al4V after being subjected to UV-C light. It has been recently hypothesized that small surface currents, occurring as a consequence of the electron-hole pair recombination taking place after the excitation process, are behind the bactericidal properties displayed by this UV-treated material. To corroborate this hypothesis we have used different electrochemical techniques, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization plots and Mott-Schottky plots. EIS and Mott-Schottky plots have shown that UV-C treatment causes an initial increase on the surface electrical conduction of this material. In addition, EIS and polarization plots demonstrated that higher corrosion currents occur at the UV treated than at the non-irradiated samples. Despite this increase in the corrosion currents, EIS has also shown that such currents are not likely to affect the good stability of this material oxide film since the irradiated samples completely recovered the control values after being stored in dark conditions for a period not longer than 24h. These results agree with the already-published in vitro transitory behavior of the bactericidal effect, which was shown to be present at initial times after the biomaterial implantation, a crucial moment to avoid a large number of biomaterial associated infections.

  9. UV photolysis of diclofenac in water; kinetics, degradation pathway and environmental aspects.

    PubMed

    Kovacic, Marin; Juretic Perisic, Daria; Biosic, Martina; Kusic, Hrvoje; Babic, Sandra; Loncaric Bozic, Ana

    2016-08-01

    In this study, the photolysis behavior of commonly used anti-inflammatory drug diclofenac (DCF) was investigated using UV-C and UV-A irradiation. In that purpose, DCF conversion kinetics, mineralization of organic content, biodegradability, and toxicity were monitored and compared. The results showed different kinetics of DCF conversion regarding the type of UV source applied. However, in both cases, the mineralization extent reached upon complete DCF conversion is rather low (≤10 %), suggesting that the majority of DCF was transformed into by-products. Formation/degradation of main degradation by-products was monitored using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS), whereas different profiles were obtained by UV-C and UV-A photolysis. The results of bioassays revealed that biodegradability of DCF solutions remained low through the applied treatments. The toxicity of irradiated DCF solutions was evaluated using Vibrio fischeri. A significant reduction of toxicity, especially in the case of UV-A radiation, was observed upon complete degradation of DCF. In addition to toxicity reduction, calculated Log K OW values of DCF degradation by-products indicate their low potential for bioaccumulation (Log K OW ≤ 3) in comparison to the parent substance.

  10. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana.

    PubMed

    Stefanato, Francesca L; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-05-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mutants. A B. cinerea strain lacking functional BcatrB is more sensitive to camalexin in vitro and less virulent on wild-type plants, but is still fully virulent on camalexin-deficient mutants. Pre-treatment of A. thaliana with UV-C leads to increased camalexin accumulation and substantial resistance to B. cinerea. UV-C-induced resistance was not seen in the camalexin-deficient mutants cyp79B2/B3, cyp71A13, pad3 or pad2, and was strongly reduced in ups1. Here we demonstrate that an ABC transporter is a virulence factor that increases tolerance of the pathogen towards a phytoalexin, and the complete restoration of virulence on host plants lacking this phytoalexin.

  11. Application of a 222-nm krypton-chlorine excilamp to control foodborne pathogens on sliced cheese surfaces and characterization of the bactericidal mechanisms.

    PubMed

    Ha, Jae-Won; Lee, Jae-Ik; Kang, Dong-Hyun

    2017-02-21

    This study was conducted to investigate the basic spectral properties of a 222-nm krypton-chlorine (KrCl) excilamp and its inactivation efficacy against major foodborne pathogens on solid media, as well as on sliced cheese compared to a conventional 254-nm low-pressure mercury (LP Hg) lamp. Selective media and sliced cheese inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes were irradiated with a KrCl excilamp and a LP Hg lamp at the same dose. The KrCl excilamp showed full radiant intensity from the outset at a wide range of working temperatures, especially at low temperatures of around 0 to 10°C. Irradiation with 222nm UV-C showed significantly (P<0.05) higher inactivation capacity against all three pathogens than 254-nm radiation on both media and sliced cheese surfaces without generating many sublethally injured cells which potentially could recover. The underlying inactivation mechanisms of 222-nm KrCl excilamp treatment were evaluated by fluorescent staining methods and damage to cellular membranes and intracellular enzyme inactivation were the primary factors contributing to the enhanced bactericidal effect. The results of this study suggest that a 222-nm UV-C surface disinfecting system can be applied as an alternative to conventional LP Hg lamp treatment by the dairy industry.

  12. Inactivation of Caliciviruses

    PubMed Central

    Nims, Raymond; Plavsic, Mark

    2013-01-01

    The Caliciviridae family of viruses contains clinically important human and animal pathogens, as well as vesivirus 2117, a known contaminant of biopharmaceutical manufacturing processes employing Chinese hamster cells. An extensive literature exists for inactivation of various animal caliciviruses, especially feline calicivirus and murine norovirus. The caliciviruses are susceptible to wet heat inactivation at temperatures in excess of 60 °C with contact times of 30 min or greater, to UV-C inactivation at fluence ≥30 mJ/cm2, to high pressure processing >200 MPa for >5 min at 4 °C, and to certain photodynamic inactivation approaches. The enteric caliciviruses (e.g.; noroviruses) display resistance to inactivation by low pH, while the non-enteric species (e.g.; feline calicivirus) are much more susceptible. The caliciviruses are inactivated by a variety of chemicals, including alcohols, oxidizing agents, aldehydes, and β-propiolactone. As with inactivation of viruses in general, inactivation of caliciviruses by the various approaches may be matrix-, temperature-, and/or contact time-dependent. The susceptibilities of the caliciviruses to the various physical and chemical inactivation approaches are generally similar to those displayed by other small, non-enveloped viruses, with the exception that the parvoviruses and circoviruses may require higher temperatures for inactivation, while these families appear to be more susceptible to UV-C inactivation than are the caliciviruses. PMID:24276023

  13. Improvement of oleuropein extractability by optimising steam blanching process as pre-treatment of olive leaf extraction via response surface methodology.

    PubMed

    Stamatopoulos, Konstantinos; Katsoyannos, Evangelos; Chatzilazarou, Arhontoula; Konteles, Spyros J

    2012-07-15

    Impact of steam, hot water blanching and UV-C irradiation as pre-treatments on extraction of oleuropein and related biophenols from olive leaves (OLs), was investigated. Moreover, particle size effect of olive leaves and steam blanching duration were selected as independent variables to optimise steam blanching process in terms of oleuropein content (OC) and antioxidant activity (AC) of ethanolic extracts, by using response surface methodology. Optimum conditions for OC and AC were 10 min steam blanching of 20-11 and 3-1mm olive leaf fraction, respectively. Depending on the extraction procedure, at optimum conditions of steaming the results indicate that steam blanching of OL prior to extraction can significantly increase oleuropein yield from 25 to 35 times compared to non-steam blanched sample, whereas the antioxidant activity increased from 4 to 13 times. No significant UV-C effect was observed in OC and AC, while hot water blanched samples showed significantly higher oleuropein yields and antioxidant activity compared to untreated samples.

  14. Phototransformation of selected pharmaceuticals during UV treatment of drinking water.

    PubMed

    Canonica, Silvio; Meunier, Laurence; von Gunten, Urs

    2008-01-01

    The kinetics of Ultraviolet C (UV-C)-induced direct phototransformation of four representative pharmaceuticals, i.e., 17alpha-ethinylestradiol (EE2), diclofenac, sulfamethoxazole, and iopromide, was investigated in dilute solutions of pure water buffered at various pH values using a low-pressure and a medium-pressure mercury arc lamp. Except for iopromide, pH-dependent rate constants were observed, which could be related to acid-base equilibria. Quantum yields for direct phototransformation were found to be largely wavelength-independent, except for EE2. This compound, which also had a rather inefficient direct phototransformation, mainly underwent indirect phototransformation in natural water samples, while the UV-induced depletion of the other pharmaceuticals appeared to be unaffected by the presence of natural water components. At the UV-C (254 nm) drinking-water disinfection fluence (dose) of 400 Jm(-2), the degree of depletion of the select pharmaceuticals at pH=7.0 in pure water was 0.4% for EE2, 27% for diclofenac, 15% for sulfamethoxazole, and 15% for iopromide, indicating that phototransformation should be seriously taken into account when evaluating the possibility of formation of UV transformation products from pharmaceuticals present as micropollutants.

  15. UV-based technologies for marine water disinfection and the application to ballast water: Does salinity interfere with disinfection processes?

    PubMed

    Moreno-Andrés, Javier; Romero-Martínez, Leonardo; Acevedo-Merino, Asunción; Nebot, Enrique

    2017-03-01

    Water contained on ships is employed in the majority of activities on a vessel; therefore, it is necessary to correctly manage through marine water treatments. Among the main water streams generated on vessels, ballast water appears to be an emerging global challenge (especially on cargo ships) due to the transport of invasive species and the significant impact that the ballast water discharge could have on ecosystems and human activities. To avoid this problem, ballast water treatment must be implemented prior to water discharge in accordance with the upcoming Ballast Water Management Convention. Different UV-based treatments (photolytic: UV-C and UV/H2O2, photocatalytic: UV/TiO2), have been compared for seawater disinfection. E. faecalis is proposed as a biodosimeter organism for UV-based treatments and demonstrates good properties for being considered as a Standard Test Organism for seawater. Inactivation rates by means of the UV-based treatments were obtained using a flow-through UV-reactor. Based on the two variables responses that were studied (kinetic rate constant and UV-Dose reductions), both advanced oxidation processes (UV/H2O2 and photocatalysis) were more effective than UV-C treatment. Evaluation of salinity on the processes suggests different responses according to the treatments: major interference on photocatalysis treatment and minimal impact on UV/H2O2.

  16. Effect of photochemical pre-treatment on COD fractionation of a non-ionic textile surfactant.

    PubMed

    Cokgor, E U; Arsian-Alaton, I; Erdinc, E; Insel, G; Orhon, D

    2007-01-01

    The work presented in this paper is focused on the effect of photochemical (H2O2/UV-C) pretreatment on COD fractionation and degradation kinetics of a non-ionic textile surfactant. In the first part of the study, the COD of non-ionic surfactant was adjusted to 1000 mg/L in order to simulate real effluent originating from the textile preparation stage featuring desizing, scouring, washing and rinsing operations. The surfactant was subjected to H2O2/UV-C pretreatment for up to 120 min at a dose of 30 mM (980 mg/L) H2O2. The biodegradability studies for untreated and photochemically treated samples were evaluated on the basis of modeling of oxygen uptake rate (OUR) profiles. Modelling of OUR profiles conducted for untreated sample showed that single complex substrate was subjected to enzymatic breakdown and disintegrated into one readily and two types of slowly biodegradable substrates. After modelling the biodegradation of photochemically pretreated sample, the readily biodegradable COD fraction was reduced, on the other hand, more slowly biodegradable organics were generated. A higher disintegration rate was obtained for chemically pretreated samples. However, other kinetic constants of growth and hydrolysis processes were not affected considerably.

  17. Assessment of the Suitability of Excimer Lasers in Treating Onychomycosis

    NASA Astrophysics Data System (ADS)

    Kymplová, Jaroslava; Jelínek, Miroslav; Urzová, Jana; Mikšovský, Jan; Dušek, Karel; Bauerová, Lenka

    2014-04-01

    Since it is known that UV-C radiation kills fungus, we wanted to verify the hypothesis that the use of excimer laser could be an alternative method for treating onychomycosis - nail fungus. The aim of the first stage of this work was to determine the transmission, reflection and absorption of nails. In the following stage we focused on irradiation of fungi. Our final task is to assess whether it is possible to determine the parameters of radiation (a total dose,a dose per pulse frequency, a repetition rate, a number of pulses) for which the elimination of fungi would be the most effective but without damaging the nail and soft tissue underneath it. The results so far have showed that UV-C radiation does not pass through a fingernail to such an extent that it could damage the soft tissue beneath it. Fungi are destroyed by the application of only small doses of radiation using the excimer laser. Additional measurements will be required to determine the modulation parameters of the excimer laser radiation for the treatment of onychomycosis.

  18. Influence of dimethyl dicarbonate on the resistance of Escherichia coli to a combined UV-Heat treatment in apple juice

    PubMed Central

    Gouma, Maria; Gayán, Elisa; Raso, Javier; Condón, Santiago; Álvarez, Ignacio

    2015-01-01

    Commercial apple juice inoculated with Escherichia coli was treated with UV-C, heat (55°C) and dimethyl dicarbonate – DMDC (25, 50, and 75 mg/L)-, applied separately and in combination, in order to investigate the possibility of synergistic lethal effects. The inactivation levels resulting from each treatment applied individually for a maximum treatment time of 3.58 min were limited, reaching 1.2, 2.9, and 0.06 log10 reductions for UV, heat, and DMDC (75 mg/L), respectively. However, all the investigated combinations resulted in a synergistic lethal effect, reducing the total treatment time and UV dose, with the synergistic lethal effect being higher when larger concentrations of DMDC were added to the apple juice. The addition of 75 mg/L of DMDC prior to the combined UV-C light treatment at 55°C resulted in 5 log10 reductions after only 1.8 min, reducing the treatment time and UV dose of the combined UV-Heat treatment by 44%. PMID:26042117

  19. Sub-50 fs excited state dynamics of 6-chloroguanine upon deep ultraviolet excitation.

    PubMed

    Mondal, Sayan; Puranik, Mrinalini

    2016-05-18

    The photophysical properties of natural nucleobases and their respective nucleotides are ascribed to the sub-picosecond lifetime of their first singlet states in the UV-B region (260-350 nm). Electronic transitions of the ππ* type, which are stronger than those in the UV-B region, lie at the red edge of the UV-C range (100-260 nm) in all isolated nucleobases. The lowest energetic excited states in the UV-B region of nucleobases have been investigated using a plethora of experimental and theoretical methods in gas and solution phases. The sub-picosecond lifetime of these molecules is not a general attribute of all nucleobases but specific to the five primary nucleobases and a few xanthine and methylated derivatives. To determine the overall UV photostability, we aim to understand the effect of more energetic photons lying in the UV-C region on nucleobases. To determine the UV-C initiated photophysics of a nucleobase system, we chose a halogen substituted purine, 6-chloroguanine (6-ClG), that we had investigated previously using resonance Raman spectroscopy. We have performed quantitative measurements of the resonance Raman cross-section across the Bb absorption band (210-230 nm) and constructed the Raman excitation profiles. We modeled the excitation profiles using Lee and Heller's time-dependent theory of resonance Raman intensities to extract the initial excited state dynamics of 6-ClG within 30-50 fs after photoexcitation. We found that imidazole and pyrimidine rings of 6-ClG undergo expansion and contraction, respectively, following photoexcitation to the Bb state. The amount of distortions of the excited state structure from that of the ground state structure is reflected by the total internal reorganization energy that is determined at 112 cm(-1). The contribution of the inertial component of the solvent response towards the total reorganization energy was obtained at 1220 cm(-1). In addition, our simulation also yields an instantaneous response of the first

  20. Trace Contaminant Control: An In-Depth Study of a Silica-Titania Composite for Photocatalytic Remediation of Closed-Environment Habitat Air

    NASA Technical Reports Server (NTRS)

    Coutts, Janelle L.

    2013-01-01

    This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-TiO2 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp O max=365 nm) at its maximum light intensity or a UV-C germicidal lamp O. max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1 ) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol C02 mol photons-1 ). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV -A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy. The effect of temperature and relative humidity on the STC-catalyzed degradation of ethanol was also determined using the UV-A light source at its maximum intensity.

  1. The effects of space relevant environmental factors on halophilic Archaea

    NASA Astrophysics Data System (ADS)

    Leuko, Stefan; Moeller, Ralf; Rettberg, Petra

    Within the last 50 years, space technology has provided tools for transporting terrestrial (microbial) life beyond Earth's protective shield in order to study its responses to selected conditions of space. Microorganisms are ubiquitous and can be found in almost every environment on Earth. They thrive and survive in a broad spectrum of environments and are true masters in adapting to rapidly changing external conditions. Although microorganisms cannot actively grow under the harsh conditions of outer space or other known planets, some microorganisms might be able to survive for a time in space or other planets as dormant, inactive spores or in similar desiccation-resistant resting states, e.g., enclosed in halite crystals or biofilms. Halite crystals are the realm of halophilic Archaea as they have adapted to life at extreme salt concentrations. They can stay entrapped in such crystals for millions of years without losing viability and therefore the family Halobacteriaceae belongs to the group of microorganisms which may survive space travel or may even be found on other planets. Several members of this family have been utilized in space relevant experiments where they were exposed to detrimental environmental conditions such as UV-C radiation, vacuum, temperature cycles (+60(°) C and -25(°) C) and heavy iron bombardment (150 MeV He, 500 MeV Ar and 500 MeV Fe ions). The viability was evaluated by colony forming unit (cfu) counts as well as with the LIFE/DEAD kit. Results revealed that UV-C radiation (up to 1.000 J/m (2) ) has a considerable effect on the viability, whereas the other tested parameters inflict little damage onto the organisms. Repair of UV-C inflicted damage is efficient and several DNA damage repair genes are up-regulated following exposure. Halophilic archaea display a strong resistance against heavy iron bombardment, with dosages of up to 2.000 Gy 500 MeV Fe ions needed to establish a visible effect on the vitality. Genomic integrity after

  2. Properties of Waste from Coal Gasification in Entrained Flow Reactors in the Aspect of Their Use in Mining Technology / Właściwości odpadów ze zgazowania węgla w reaktorach dyspersyjnych w aspekcie ich wykorzystania w technologiach górniczych

    NASA Astrophysics Data System (ADS)

    Pomykała, Radosław

    2013-06-01

    Most of the coal gasification plants based of one of the three main types of reactors: fixed bed, fluidized bed or entrained flow. In recent years, the last ones, which works as "slagging" reactors (due to the form of generated waste), are very popular among commercial installations. The article discusses the characteristics of the waste from coal gasification in entrained flow reactors, obtained from three foreign installations. The studies was conducted in terms of the possibilities of use these wastes in mining technologies, characteristic for Polish underground coal mines. The results were compared with the requirements of Polish Standards for the materials used in hydraulic backfill as well as suspension technology: solidification backfill and mixtures for gob caulking. Większość przemysłowych instalacji zgazowania węgla pracuje w oparciu o jeden z trzech głównych typów reaktorów: ze złożem stałym, dyspersyjny lub fluidalny. W zależności od rodzaju reaktora oraz szczegółowych rozwiązań instalacji, powstające uboczne produkty zgazowania mogą mieć różną postać. Zależy ona w dużej mierze od stosunku temperatury pracy reaktora do temperatury topnienia części mineralnych zawartych w paliwie, czyli do temperatury mięknienia i topnienia popiołu. W ostatnich latach bardzo dużą popularność wśród instalacji komercyjnych zdobywają reaktory dyspersyjne "żużlujące". W takich instalacjach żużel jest wychwytywany i studzony po wypłynięciu z reaktora. W niektórych przypadkach oprócz żużla powstaje jeszcze popiół lotny, wychwytywany w systemach odprowadzania spalin. Może być on pozyskiwany oddzielnie lub też zawracany do komory reaktora, gdzie ulega stopieniu. Wszystkie z analizowanych odpadów - trzy żużle oraz popiół pochodzą właśnie z tego typu instalacji. Tylko z jednej z nich pozyskano zarówno żużel jak i popiół, z pozostałych dwóch jedynie żużel. Odpady te powstały, jako uboczny produkt zgazowania w

  3. Development of Load Exerted on the Lining of the Shaft After its Liquidation / Kształtowanie Się Obciążeń Obudowy Szybu Po Jego Likwidacji

    NASA Astrophysics Data System (ADS)

    Konior, Janusz

    2015-03-01

    .jpg" /> przy czym osiągają je już około 20÷40 m pod ustabilizowanym poziomem podsadzki w szybie. W prawidłowo zlikwidowanym szybie podsadzka winna szczelnie wypełniać rurę szybową do poziomu zrębu, a w przypadku wystąpienia procesu jej osiadania - okresowo uzupełniana. W takim przypadku obciążenie wypadkowe obudowy zlikwidowanego szybu można wyrazić wzorami (12), (13). Jednak w zależności od rodzaju zastosowanego materiału podsadzkowego do likwidacji szybu, jak to wynika z prowadzonych badań ich parametry fizyko-mechaniczne mogą ulegać zmianie w czasie w mniejszym lub większym stopniu. W artykule powołano się na badania górniczych materiałów odpadowych pochodzących z robót dołowych i przeróbczych. Zmianę istotnych parametrów, z punktu widzenia obliczanych wartości obciążenia pionowego i poziomego wywieranego przez podsadzkę na obudowę zlikwidowanego szybu przedstawiono na wykresach 3 i 4. Uwzględnienie tych zmian dla przedstawionego przykładu obliczeniowego wykazało wzrost wielkości parcia podsadzki o około 19%. Ponadto w zlikwidowanych szybach, w których występuje dopływ wody zza obudowy koniecznym jest, aby materiał użyty do likwidacji posiadał wymagany współczynnik filtracji, co obrazuje graficzna interpretacja przykładowych wyników obliczeń przedstawiona na Rys. 6. Nawet prawidłowo dobrany materiał zasypowy (z punktu widzenia wymaganej wartości współczynnika filtracji) może ulegać zmianom uziarnienia w wyniku takich czynników jak: swobodny spadek do szybu w czasie likwidacji, długotrwałe narażenie na oddziaływanie wody, wynoszenie drobnych cząstek gruntu wraz z wodą dopływającą zza obudowy (sufozja) itp. Przykład zmiany współczynnika filtracji związany ze zmianą uziarnienia badanego materiału przedstawia Rys. 7. W wyniku zmiany wartości współczynnika filtracji w czasie może dojść do gromadzenia się wody w podsadzce, co powoduje dalszy wzrost obci

  4. Koncepcja resilience. Kluczowe pojęcia i wybrane zagadnienia

    PubMed Central

    Borucka, Anna; Ostaszewski, Krzysztof

    2009-01-01

    Streszczenie Celem niniejszej pracy jest przybliżenie kluczowych pojęć związanych koncepcją resilience. Ta koncepcja wyjaśnia fenomen pozytywnej adaptacji dzieci i młodzieży narażonych na duże ryzyko, przeciwności losu i/lub zdarzenia traumatyczne. Koncepcja resilience akcentuje znaczenie czynników i mechanizmów chroniących w wieku rozwojowym. Z tych przyczyn może być bardzo użyteczna dla rozwijania programów profilaktyki i promocji zdrowia psychicznego wśród dzieci i młodzieży. W niniejszym przeglądzie wykorzystano prace znaczących Autorów zajmujących się tą dziedziną m.in. M. Ruttera. N. Garmezy, E. Werner, S. Luthar, A. Sameroffa, K. Kumpfer, A. Masten, M. Zimmermana, D. Cicchetti. W przeglądzie uwzględniono ponad 20 artykułów i rozdziałów książkowych, które ukazały się w ostatnich 25 latach. Zostały one wybrane z elektronicznej bazy publikacji dostępnej na Uniwersytecie Michigan: elektronicznej bazy SAMSHA oraz z elektronicznych baz publikacji naukowych dostępnych w naszym kraju. W artykule przytoczono kilka definicji resilience, które wskazują na jej interaktywny i dynamiczny charakter. Uwzględniają one wzajemny wpływ czynników ryzyka i czynników chroniących (i ich interakcję) na zachowanie człowieka, jego kompetencje i zdrowie psychiczne. W pracy opisano podstawowe pojęcia związane z resilience: ryzyko, czynniki ryzyka, czynniki chroniące, pozytywną adaptację oraz teoretyczne modele i mechanizmy resilience. Przedstawiono różnice między mechanizmami ryzyka a mechanizmami chroniącymi. Zasygnalizowano też trudności związane z wykorzystaniem podstawowych pojęć resilience w badaniach empirycznych m.in. w określeniu wskaźników ryzyka, wyodrębnieniu grup ryzyka, określeniu wskaźników pozytywnej adaptacji. PMID:19301507

  5. Elements of the Chicxulub Impact Structure as revealed in SRTM and surface GPS topographic data

    NASA Astrophysics Data System (ADS)

    Kobrick, M.; Kinsland, G. L.; Sanchez, G.; Cardador, M. H.

    2003-04-01

    Pope et al have utilized elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxu-lub Impact Structure is a roughly semi-circular, low-relief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact which possibly led to the development of these features. Kinsland et al presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Shaded relief images from recently acquired SRTM elevation data clearly show the circular depression of the crater and the moat/cenote ring. In addition we can readily identify Inner trough 1, Inner trough 2 and Outer trough as defined by Pope et al. The agreement between the topographic maps of Pope et al, Kinsland et al and SRTM data are remarkable considering that the distribution and types of data in the sets are so different. We also have ground topographic data collected with a special "autonomous differ-ential GPS" system during summer 2002. Profiles from these data generally agree with both the gravity data based topographic maps and profiles extracted from the SRTM data. Preliminary analyses of our new data, SRTM and GPS, have uncovered features not previously recognized: 1) as shown by the GPS data the moat/cenote ring consists of two distinct depressions separated by about 10 km...perhaps separate ring faults, 2) in the SRTM data over the southern part of the crater and on southward for perhaps 20 km beyond the moat/ cenote ring there exists a pattern, as yet unexplained, of roughly concentric topographic features whose center lies at about 21deg 40min N and 89deg 25min W, about 50km NNE of the moat/cenote ring center. The corroboration and better definition of the previously recognized topographic features yielded by the two new forms of data strengthens the cases for these fea-tures and for their relevance to the underlying

  6. A fixed granular-bed sorber for measurement and control of alkali vapors in PFBC (pressurized fluidized-bed combustion)

    SciTech Connect

    Lee, S.H.D.; Swift, W.M.

    1990-01-01

    Alkali vapors (Na and K) in the hot flue gas from the pressurized fluidized-bed combustion (PFBC) of coal could cause corrosion problems with the gas turbine blades. In a laboratory-scale PFBC test with Beulah lignite, a fixed granular bed of activated bauxite sorbent was used to demonstrate its capability for measuring and controlling alkali vapors in the PFBC flue gas. The Beulah lignite was combusted in a bed of Tymochtee dolomite at bed temperatures ranging from 850 to 875{degrees}C and a system pressure of 9.2 atm absolute. The time-averaged concentration of sodium vapor in the PFBC flue gas was determined from the analysis of two identical beds of activated bauxite and found to be 1.42 and 1.50 ppmW. The potassium vapor concentration was determined to be 0.10 ppmW. The sodium material balance showed that only 0.24% of the total sodium in the lignite was released as vapor species in the PFBC flue gas. This results in an average of 1.56 ppmW alkali vapors in the PFBC flue gas. This average is more than 1.5 orders of magnitude greater than the currently suggested alkali specification limit of 0.024 ppm for an industrial gas turbine. The adsorption data obtained with the activated bauxite beds were also analyzed mathematically by use of a LUB (length of unused bed)/equilibrium section concept. Analytical results showed that the length of the bed, L{sub o} in centimeters, relates to the break through time, {theta}{sub b} in hours, for the alkali vapor to break through the bed as follows: L{sub o} = 33.02 + 1.99 {theta}{sub b}. This formula provides useful information for the engineering design of fixed-bed activated bauxite sorbers for the measurement and control of alkali vapors in PFBC flue gas. 26 refs., 4 figs., 4 tabs.

  7. Organization of the human LU gene and molecular basis of the Lu(a)/Lu(b) blood group polymorphism.

    PubMed

    El Nemer, W; Rahuel, C; Colin, Y; Gane, P; Cartron, J P; Le Van Kim, C

    1997-06-15

    hamster ovary (CHO) cells, Lu cDNAs carrying the A229 or the G229 produced cell surface proteins that reacted with anti-Lu(a) or anti-Lu(b) antibodies, respectively, showing that these nucleotides specify the Lu(a) and Lu(b) alleles of the Lutheran blood group locus. CHO cells expressing recombinant short-tail or long-tail Lu glycoproteins reacted as well with anti-Lu as with anti-B-CAM antibodies, providing the definitive proof that the Lu blood group and B-CAM antigens are carried by the same molecules.

  8. The geovisualisation window of the temporal and spatial variability for Volunteered Geographic Information activities

    NASA Astrophysics Data System (ADS)

    Medynska-Gulij, Beata; Myszczuk, Miłosz

    2012-11-01

    This study presents an attempt to design geographical visualisation tools that allow to tackle the immensity of spatial data provided by Volunteered Geographic Information (VGI), both in terms of temporal and spatial aspects. In accordance with the assumptions made at the conceptual stage, the final action was the implementation of the window entitled ‘Geovisualisation of the Panoramio.com Activities in District of Poznan 2011’ into the web browser. The concept has been based on a division of the geovisualisation window into three panels, of which the most important - in order to capture spatial variability - have statistical maps at the general level (dot map and choropleth map), while at the detailed level - a dot map on a topographic reference map or tourist map. For two ranges, temporal variability is presented by graphs, while a review of attributes of individual activities of the social website in question is set forward in the table panel. The element that visually interlinks all of the panels is the emphasised individual activity. Problemem podjetym w tych badaniach stało sie wykorzystanie metod z nurtu geograficznej wizualizacji do wskazania cech fenomenu VGI w zakresie zmiennosci czasowo-przestrzennej. Zgodnie z załozeniami poczynionymi w etapie koncepcyjnym finalnym działaniem stało sie zaimplementowanie do przegladarki internetowej okna pod tytułem: ”Geowizualizacja aktywnosci społecznosci Panoramio.com w powiecie poznanskim w 2011 roku”. Koncepcja została oparta na podziale okna geowizualizacji na trzy panele, z których najwazniejsze znaczenie dla uchwycenia zmiennosci przestrzennej na poziomie ogólnym ma kartogram, natomiast na poziomie szczegółowym mapa kropkowa wyswietlana na podkładzie mapy topograficznej lub turystycznej. Zmiennosc czasowa w dwóch zakresach prezentuja wykresy, a przeglad atrybutów poszczególnych aktywnosci prezentowanego portalu społecznosciowego zapewnia tabela. Elementem spajajacym wizualnie wszystkie

  9. Organisational aspects of spatial information infrastructure in Poland

    NASA Astrophysics Data System (ADS)

    Bielecka, Elzbieta; Zwirowicz-Rutkowska, Agnieszka

    2013-06-01

    One of the more important elements of spatial information infrastructure is the organisational structure defining the obligations and dependencies between stakeholders that are responsible for the infrastructure. Many SDI practitioners and theoreticians emphasise that its influence on the success or failure of activities undertaken is significantly greater than that of technical aspects. Being aware of the role of the organisational structure in the creating, operating and maintenance of spatial information infrastructure (SII), Polish legislators placed appropriate regulations in the Spatial Information Infrastructure Act, being the transposition of the INSPIRE Directive into Polish Law. The principal spatial information infrastructure stakeholders are discussed in the article and also the scope of cooperation between them. The tasks and relationships between stakeholders are illustrated in UML, in both the use case and the class diagram. Mentioned also are the main problems and obstructions resulting from imprecise legal regulations. Jednym z istotniejszych komponentów infrastruktury informacji przestrzennej (IIP) jest struktura organizacyjna określająca m.in. zależności pomiędzy organizacjami tworzącymi infrastrukturę. Wielu praktyków i teoretyków SDI podkreśla, że wpływ aspektów organizacyjnych na sukces lub porażkę SDI jest dużo większy niż elementów technicznych. Mając świadomość znaczącej roli struktury organizacyjnej w tworzeniu, funkcjonowaniu i zarządzaniu infrastrukturą przestrzenną w Polsce, legislatorzy umieścili odpowiednie zapisy w ustawie z dnia 4 marca 2010 r. o infrastrukturze informacji przestrzennej, będącej transpozycją dyrektywy INSPIRE do prawa polskiego. W artykule omówiono strukturę organizacyjną IIP w Polsce, podając (m.in. w postaci diagramów UML) obowiązki poszczególnych organów administracji zaangażowanych w jej budowę i rozwój, a także omówiono zależności i zakres współpracy pomi

  10. Printable UV personal dosimeter: sensitivity as a function of DoD parameters and number of layers of a functional photonic ink

    NASA Astrophysics Data System (ADS)

    Sousa, Felipe L. N.; Mojica-Sánchez, Lizeth C.; Gavazza, Sávia; Florencio, Lourdinha; Vaz, Elaine C. R.; Santa-Cruz, Petrus A.

    2016-04-01

    This work presents ‘intelligent papers’ obtained by functional inks printed on cellulose-sheets by DoD inkjet technology and their performance as a photonic device for UV-radiation dosimetry. The dosimeter operation is based on the photodegradation of the active part of a photonic ink, btfa (4,4,4-trifluoro-1-phenyl-1,3-butanedione) ligands in Eu(III) complex, as a function of the UV dose (Jcm-2), and the one-way device is read by the luminescence quenching of (5D0 → 7F2) Eu3+ transition after UV exposure of the printed paper. The printed dosimeter presented an exponential behavior, measured here up to 10 Jcm-2 for UV-A, UV-B and UV-C, and it was shown that the number of jetted layers could fit the dosimeter sensitivity.

  11. Cytoprotective alginate/polydopamine core/shell microcapsules in microbial encapsulation.

    PubMed

    Kim, Beom Jin; Park, Taegyun; Moon, Hee Chul; Park, So-Young; Hong, Daewha; Ko, Eun Hyea; Kim, Ji Yup; Hong, Jong Wook; Han, Sang Woo; Kim, Yang-Gyun; Choi, Insung S

    2014-12-22

    Chemical encapsulation of microbes in threedimensional polymeric microcapsules promises various applications, such as cell therapy and biosensors, and provides a basic platform for studying microbial communications. However, the cytoprotection of microbes in the microcapsules against external aggressors has been a major challenge in the field of microbial microencapsulation, because ionotropic hydrogels widely used for microencapsulation swell uncontrollably, and are physicochemically labile. Herein, we developed a simple polydopamine coating for obtaining cytoprotective capability of the alginate capsule that encapsulated Saccharomyces cerevisiae. The resulting alginate/ polydopamine core/shell capsule was mechanically tough, prevented gel swelling and cell leakage, and increased resistance against enzymatic attack and UV-C irradiation. We believe that this multifunctional core/shell structure will provide a practical tool for manipulating microorganisms inside the microcapsules.

  12. Synthesis, characterization and photocatalytic behavior of Ag doped TiO2 thin film

    NASA Astrophysics Data System (ADS)

    Bensouici, F.; Souier, T.; Dakhel, A. A.; Iratni, A.; Tala-Ighil, R.; Bououdina, M.

    2015-09-01

    In this study, structure, microstructure, optical properties and photocatalytic degradation of Rhodamine B (RhB) have been investigated in an aqueous heterogeneous media containing pure and Ag doped TiO2 nanostructures thin films which were prepared by a simple sol-gel route. Thermal analysis demonstrated that Ag content decreased the temperature of anatase-to-rutile phase transformation. X-ray diffraction analysis confirmed that the prepared nanostructures crystallize within anatase-type structure and that the dopant Ag ions were not fully incorporated within TiO2 host lattice, meanwhile both the refractive index and optical band gap were affected by Ag concentration. The photodegradation of Rhodamine B under UV-C radiation by using pure and Ag-doped TiO2 nanostructures showed that Ag played an important role in a significant improvement of the photodegradation efficiency and that the optimum content of Ag ions was found to be 0.5% molar ratio.

  13. Fluorescence diagnosis in tissue injury

    NASA Astrophysics Data System (ADS)

    Maciel, Vitória H.; Ferreira, Juliana; Bagnato, Vanderlei S.

    2009-06-01

    Background and Objectives: The paper aim was to evaluate the efficacy of the fluorescence spectroscopy in the detection of UV-induced skin change of Wistar rats. Study Design/ Materials and Methods: In a group male Wistar rats, the skin damage was produced by an UV-C lamp, periodically monitored using the laser-induced fluorescence, until complete healing process. After determining a characteristic emission band present in the fluorescence spectra of the induced injuries, the amplitude band monitoring allowed the follow up on the injury and the recovery. Results: We observed the appearance of two new emission bands more evident at the injury spectra when compared to the spectrums from normal non-exposed tissue. Following such spectral bands was possible to observe the establishment and recovery. Conclusions: The fluorescence spectroscopy is a promising technique in distinguishing between normal and UV induced skin change helping the evaluation of changes which are irreversible cancer tissue characteristics.

  14. Ultraviolet-induced oxidation of ascorbic acid in a model juice system: identification of degradation products.

    PubMed

    Tikekar, Rohan V; Anantheswaran, Ramaswamy C; Elias, Ryan J; LaBorde, Luke F

    2011-08-10

    Degradation products of ultraviolet (UV-C, 254 nm) treated ascorbic acid (AA) are reported. Analysis by high-performance liquid chromatography-mass spectroscopy (HPLC-MS) conducted in a 0.5% malic acid model juice system (pH 3.3) demonstrated increased degradation of AA above untreated controls with concomitant increases in dehydroascorbic acid (DHA) and 2,3-diketogulonic acid (DKGA) levels. Electron spin resonance (ESR) spectroscopy studies, conducted in phosphate buffer (pH 7.0) to increase detection sensitivity, demonstrated that ascorbyl radical (AA•) formation occurs simultaneously with AA degradation. Consistent with a previous study in which UV treatments were shown to accelerate dark storage degradation, AA• radicals continued to form for up to 200 min after an initial UV treatment. Results from this study suggest that the mechanism for UV-induced degradation is the same as the general mechanism for metal-catalyzed oxidation of AA in juice.

  15. The investigation of the light radiation caused polyethylene based materials deterioration by means of atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Sikora, A.; Grabarek, A.; Moroń, L.; Wałecki, M.; Kryla, P.

    2016-02-01

    The impact of the environmental conditions on the materials used in various devices and constructions, in particular in electrotechnical applications, has an critical impact in terms of their reliability and utilization range in specific climatic conditions. Due to increasing utilitarian requirements, technological processes complexity and introducing new materials (for instance nanomaterials), advanced diagnostic techniques are desired. One of such techniques is atomic force microscopy (AFM), which allows to study the changes of the roughness and mechanical properties of the surface at the submicrometer scale, enabling the investigation of the degradation processes. In this work the deterioration of selected group of polyethylene based materials have been measured by means of AFM, as the samples were exposed to the simulated solar light and UV-C radiation. Such an analysis of the environmental conditions impact on the deterioration process using AFM methods for various versions of specific material was not presented before.

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

    PubMed

    Qureshi, Zubair; Yassin, Mohamed H

    2013-06-01

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

  17. Photocatalytic degradation of methylene blue over nanosized TiO2 particles prepared using the self-propagating high-temperature synthesis method.

    PubMed

    Park, Chul-Min; Seo, Hyeong-Seok; Cho, Jung-Ho; Choi, Da-Hye; Jeong, Young-Shin; Chung, Min-Chul; Jung, Sang-Chul; Jeong, Woon-Jo; Ban, Jae-Sam; Ahn, Ho-Geun

    2013-08-01

    In order to reutilize the spent metallic titanium chips, TiO2 photocatalysts were prepared using the self-propagating high-temperature synthesis (SHS) method, and were characterized by N2 gas adsorption, X-ray diffraction, and scanning electron microscope, particle size distribution. Also, their photocatalytic activities were evaluated using methylene blue as a model organic compound. It was confirmed that the crystal structure of TiO2 prepared by SHS method was relatively homogeneous powder of rutile type. Optimum conditions for photocatalytic degradation of methylene blue under UV-C irradiation were methylene blue 9.5 ppm in solution and at amount of TiO2 added of 0.02 g/L. In addition, it was found that the photocatalytic activity for methylene blue degradation over the prepared TiO2 particles was positively related with BET specific surface area.

  18. The hydroxyl radical scavenging effect of textile preparation auxiliaries on the photochemical treatment of nonylphenol ethoxylate.

    PubMed

    Arslan-Alaton, Idil; Shayin, Sarina; Olmez-Hanci, Tugba

    2012-01-01

    The present paper deals with the effects of frequently used textile preparation chemicals and common ions on the H2O2/UV-C treatment of a commercially important and slowly biodegradable nonionic surfactant, namely a nonylphenol bearing 10 ethoxylated chains. For this purpose, the effect of soda ash carbonate (0-5.0 g L(-1)), two phosphonic acid-based organic sequestering agents (0-2.5 g L(-1)) and chloride (0-3.0 g L(-1)) at two different pH values (3.5 and 10.5) as hydroxyl radical scavengers was experimentally investigated. Among the studied textile preparation chemicals and hydroxyl radical scavengers, the decreasing order of hydroxyl radical scavenging capacity was established as diethylene triamine pentamethylene phosphonic acid > 1-hydroxy ethylidene-1,1-diphosphonic acid > soda ash carbonate at pH 10.5 > chloride at pH 3.5 > chloride at pH 10.5.

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

    PubMed

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

    2011-07-15

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

  20. Lycopene control of benzophenone-sensitized lipid peroxidation

    NASA Astrophysics Data System (ADS)

    Cvetković, Dragan; Marković, Dejan

    2012-05-01

    Lycopene antioxidant activity in the presence of two different mixtures of phospholipids in hexane solution, under continuous regime of UV-irradiation from three different ranges (UV-A, UV-B, and UV-C) has been evaluated in this work. Lycopene expected role was to control lipid peroxidation, by scavenging free radicals generated by UV-irradiation, in the presence and in the absence of selected photosensitizer, benzophenone. This work shows that lycopene undergoes to UV-induced destruction (bleaching), highly dependent on the incident photons energy input, more expressed in the presence than in the absence of benzophenone. The further increase ("excess") of its bleaching is undoubtedly related to the further increase of its antioxidant activity in the presence of benzophenone, having the same cause: increase of (phospholipids peroxidation) chain-breaking activities.

  1. Photostability of plasma polymerized γ-terpinene thin films for encapsulation of OPV.

    PubMed

    Bazaka, Kateryna; Ahmad, Jakaria; Oelgemöller, Michael; Uddin, Ashraf; Jacob, Mohan V

    2017-03-30

    Optically transparent, smooth, defect-free, chemically inert and with good adhesion to a variety of substrates, plasma polymers from plant-derived secondary metabolites have been identified as promising encapsulating materials for organic electronics and photovoltaics. Here, we demonstrate that an encapsulating layer of plasma polymerized γ-terpinene reduces degradation-related loss in conversion efficiency in PCPDTBT:PC70BM solar cells under ambient operating conditions. The stability of γ-terpinene films was then investigated under extreme UV irradiation conditions as a function of deposition power. When exposed to ambient air, prolonged exposure to UV-A and UV-B light led to notable ageing of the polymer. Photooxidation was identified as the main mechanism of degradation, confirmed by significantly slower ageing when oxygen was restricted through the use of a quartz cover. Under unnatural high-energy UV-C irradiation, significant photochemical degradation and oxidation occurred even in an oxygen-poor environment.

  2. Antibacterial and antifouling activities of chitosan/TiO2/Ag NPs nanocomposite films against packaged drinking water bacterial isolates.

    PubMed

    Natarajan, Saravanan; Bhuvaneshwari, M; Lakshmi, D Shanthana; Mrudula, P; Chandrasekaran, N; Mukherjee, Amitava

    2016-10-01

    TiO2 and Ag NPs are widely used as antibacterial agents against many bacterial pathogens. Chitosan (polymer) itself acts as a strong antibacterial agent. Hence, chitosan/TiO2/Ag NPs incorporated nanocomposite film was prepared against packed drinking water bacterial strains. A concentration-dependent increase in the reduction of cell viability was observed in all the isolates under UV-C and dark exposure conditions. The bacteria consortium showed greater resistance against antibacterial effects of chitosan/TiO2/Ag nanocomposite as compared to single isolates. Glycocalyx test and mass assessment conclude the effective antibacterial activity by inhibiting bacterial adhesion on the film surface. The release of LDH and generation of ROS act as the predominant antibacterial mechanism induced by TiO2/Ag NPs. Surface characterization of chitosan/TiO2/Ag nanocomposite was studied by FTIR and XRD analyses and SEM analysis after interaction with the bacteria.

  3. Synthesis of surface bound silver nanoparticles on cellulose fibers using lignin as multi-functional agent.

    PubMed

    Hu, Sixiao; Hsieh, You-Lo

    2015-10-20

    Lignin has proven to be highly effective "green" multi-functional binding, complexing and reducing agents for silver cations as well as capping agents for the synthesis of silver nanoparticles on ultra-fine cellulose fibrous membranes. Silver nanoparticles could be synthesized in 10min to be densely distributed and stably bound on the cellulose fiber surfaces at up to 2.9% in mass. Silver nanoparticle increased in sizes from 5 to 100nm and became more polydispersed in size distribution on larger fibers and with longer synthesis time. These cellulose fiber bound silver nanoparticles did not agglomerate under elevated temperatures and showed improved thermal stability. The presence of alkali lignin conferred moderate UV absorbing ability in both UV-B and UV-C regions whereas the bound silver nanoparticles exhibited excellent antibacterial activities toward Escherichia coli.

  4. Equivalent Standard Deviation to Convert High-reliability Model to Low-reliability Model for Efficiency of Sampling-based RBDO

    DTIC Science & Technology

    2011-08-01

    Mechanics and Engineering, Vol. 198, No. 1, pp. 14-27, 2008. 32. Viana , A.C.F., Haftka, R.T., and Steffen, V ., “Multiple Surrogates: How Cross...i jX i i X j j f c u v f x f x  X x σ (28) where c is called a copula function and defined as 2 , ( , ; )( , ; ) ( , ; )uv...C u vc u v C u v u v      (29) and ( ; ) and ( ; ) i jX i i X j j u F x v F x   are CDFs for Xi and Xj

  5. VUV absorption spectroscopy of bacterial spores and DNA components

    NASA Astrophysics Data System (ADS)

    Fiebrandt, Marcel; Lackmann, Jan-Wilm; Raguse, Marina; Moeller, Ralf; Awakowicz, Peter; Stapelmann, Katharina

    2017-01-01

    Low-pressure plasmas can be used to inactivate bacterial spores and sterilize goods for medical and pharmaceutical applications. A crucial factor are damages induced by UV and VUV radiation emitted by the plasma. To analyze inactivation processes and protection strategies of spores, absorption spectra of two B. subtilis strains are measured. The results indicate, that the inner and outer coat of the spore significantly contribute to the absorption of UV-C and also of the VUV, protecting the spore against radiation based damages. As the sample preparation can significantly influence the absorption spectra due to salt residues, the cleaning procedure and sample deposition is tested for its reproducibility by measuring DNA oligomers and pUC18 plasmid DNA. The measurements are compared and discussed with results from the literature, showing a strong decrease of the salt content enabling the detection of absorption structures in the samples.

  6. Degradation testing of Mg alloys in Dulbecco's modified eagle medium: Influence of medium sterilization.

    PubMed

    Marco, Iñigo; Feyerabend, Frank; Willumeit-Römer, Regine; Van der Biest, Omer

    2016-05-01

    This work studies the in vitro degradation of Mg alloys for bioabsorbable implant applications under near physiological conditions. For this purpose, the degradation behaviour of Mg alloys in Dulbecco's modified eagle medium (DMEM) which is a commonly used cell culture medium is analysed. Unfortunately, DMEM can be contaminated by microorganisms, acidifying the medium and accelerating the Mg degradation process by dissolution of protective degradation layers, such as (Mgx,Cay)(PO4)z. In this paper the influence of sterilization by applying UV-C radiation and antibiotics (penicillin/streptomycin) is analysed with two implant material candidates: Mg-Gd and Mg-Ag alloys; and pure magnesium as well as Mg-4Y-3RE as a reference.

  7. A cytoprotective and degradable metal-polyphenol nanoshell for single-cell encapsulation.

    PubMed

    Park, Ji Hun; Kim, Kyunghwan; Lee, Juno; Choi, Ji Yu; Hong, Daewha; Yang, Sung Ho; Caruso, Frank; Lee, Younghoon; Choi, Insung S

    2014-11-10

    Single-cell encapsulation promises the cytoprotection of the encased cells against lethal stressors, reminiscent of the sporulation process in nature. However, the development of a cytocompatible method for chemically mimicking the germination process (i.e., shell degradation on-demand) has been elusive, despite the shell degradation being pivotal for the practical use of functional cells as well as for single cell-based biology. We report that an artificial shell, composed of tannic acid (TA) and Fe(III) , on individual Saccharomyces cerevisiae controllably degrades on-demand, while protecting the yeast from multiple external aggressors, including UV-C irradiation, lytic enzymes, and silver nanoparticles. Cell division is suppressed by the TA-Fe(III) shell, but restored fully upon shell degradation. The formation of a TA-Fe(III) shell would provide a versatile tool for achieving the chemical version of "sporulation and germination".

  8. Role of pigmentation in protecting Bacillus sp. endospores against environmental UV radiation.

    PubMed

    Moeller, Ralf; Horneck, Gerda; Facius, Rainer; Stackebrandt, Erko

    2005-01-01

    Bacillus endospores show different kinds of pigmentation. Red-pigmented spores of Bacillus atrophaeus DSM 675, dark-gray spores of B. atrophaeus(T) DSM 7264 and light-gray spores of B. subtilis DSM 5611 were used to study the protective role of the pigments in their resistance to defined ranges of environmental UV radiation. Spores of B. atrophaeus DSM 675 possessing a dark-red pigment were 10 times more resistant to UV-A radiation than those of the other two investigated strains, whereas the responses to the more energetic UV-B and UV-C radiation were identical in all three strains. The methanol fraction of the extracted pigment from the spores absorbs in the associated wavelength area. These results indicate that the carotene-like pigment of spores of B. atrophaeus DSM 675 affects the resistance of spores to environmental UV-A radiation.

  9. An EPR study on wastewater disinfection by peracetic acid, hydrogen peroxide and UV irradiation.

    PubMed

    Bianchini, Roberto; Calucci, Lucia; Caretti, Cecilia; Lubello, Claudio; Pinzino, Calogero; Piscicelli, Michela

    2002-09-01

    EPR spectroscopy was applied to obtain qualitative and quantitative information on the radicals produced in disinfection processes of wastewater for agricultural reuse. The DEPMPO spin trap was employed to detect hydroxyl and carbon-centered short living radicals in two different peracetic acid solutions and a hydrogen peroxide solution used for water disinfection either in the absence or in the presence of UV-C irradiation. Moreover, three different kinds of water (wastewater, demineralized water, distilled water) were analysed in order to assess the contribution of Fenton reactions to the radical production. The spectroscopic results were discussed in relation to the efficiency of the different oxidizing agents and UV irradiation in wastewater disinfection evaluated as Escherichia Coli, Faecal and Total Coliforms inactivation.

  10. Antioxidant status, peroxidase activity, and PR protein transcript levels in ascorbate-deficient Arabidopsis thaliana vtc mutants.

    PubMed

    Colville, Louise; Smirnoff, Nicholas

    2008-01-01

    Ascorbate is the most abundant small molecule antioxidant in plants and is proposed to function, along with other members of an antioxidant network, in controlling reactive oxygen species. A biochemical and molecular characterization of four ascorbate-deficient (vtc) Arabidopsis thaliana mutants has been carried out to determine if ascorbate deficiency is compensated by changes in the other major antioxidants. Seedlings grown in vitro were used to minimize stress and longer term developmental differences. Comparison was made with the low glutathione cad2 mutant and vtc2-1 treated with D,L-buthionine-[S,R]-sulphoximine to cause combined ascorbate and glutathione deficiency. The pool sizes and oxidation state of ascorbate and glutathione were not altered by deficiency of the other. alpha-Tocopherol and activities of monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, and catalase were little affected. Ascorbate peroxidase activity was higher in vtc1, vtc2-1, and vtc2-2. Ionically bound cell wall peroxidase activity was increased in vtc1, vtc2-1, and vtc4. Supplementation with ascorbate increased cell wall peroxidase activity. 2,6-Dichlorobenzonitrile, an inhibitor of cellulose synthesis, increased cell wall peroxidase activity in the wild type and vtc1. The transcript level of an endochitinase, PR1, and PR2, but not GST6, was increased in vtc1, vtc2-1, and vtc-2-2. Endochitinase transcript levels increased after ascorbate, paraquat, salicylic acid, and UV-C treatment, PR1 after salicylic acid treatment, and PR2 after paraquat and UV-C treatment. Camalexin was higher in vtc1 and the vtc2 alleles. Induction of PR genes, cell wall peroxidase activity, and camalexin in vtc1, vtc2-1, and vtc2-2 suggests that the mutants are affected in pathogen response signalling pathways.

  11. Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals.

    PubMed

    Boyce, John M

    2016-01-01

    Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer's recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid) and cold atmospheric pressure plasma show potential for use in hospitals. Creating "self-disinfecting" surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer "no-touch" (automated) decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C) light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm) light. These "no-touch" technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections. In conclusion, continued efforts to

  12. Point-of-use water disinfection using ultraviolet and visible light-emitting diodes.

    PubMed

    Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas J; Stuetz, Richard

    2016-05-15

    Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270-740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6h. Five log10 and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log10s E. coli and E. faecalis over the 6h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for >3-log10 reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5-2.5 fold at 365-455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work.

  13. Silica-Titania Composite (STC)'s Performance in the Photocatalytic Oxidation of Polar VOCs

    NASA Technical Reports Server (NTRS)

    Levine, Lanfang H.; Coutts, Janelle; Richards, Jeffrey; Mazyck, David; Mazyck, David

    2011-01-01

    The objective of this paper is to determine the performance of a Silica-Titania Composite (STC) in the photocatalytic oxidation (PCO) of polar VOCs for potential applications in trace contaminant control within space habitats such as the ISS and CEV Orion. Tests were carried out in a bench scale STC-packed annular reactor under continuous illumination by either a UV-C germicidal lamp(lambda (sub max) = 254 nm) or UV-A fluorescent BLB (lambda(sub max) = 365 nm) for the removal of ethanol (a predominant polar VOC in the ISS cabin). The STC's performance was evaluated in terms of the ethanol mineralization rate, mineralization efficiency, and the extent of its oxidation intermediate (acetaldehyde) formation in response to the type of light source (photon energy and photon flux) and relative humidity (RH) implemented. Results demonstrated that acetaldehyde was the only quantifiable intermediate in the effluent under UV illumination, but was not found in the dark adsorption experiments. The mineralization rate increased with an increase in photon energy (UV-C greater than UV-A), even though both lamps were adjusted to emit the same incident photon flux, and also increased with increasing photon flux. However, photonic efficiency decreased as the photon flux increased. More importantly, a higher photon flux gave rise to a lower effluent acetaldehyde concentration. The effect of RH on PCO was complex and intriguing because it affected both physical adsorption and photocatalytic oxidation. In general, increasing RH caused a decrease in adsorption capacity for ethanol and reduced the mineralization efficiency with a concomitant higher acetaldehyde evolution rate. The effect of RH was less profound than that of photon flux.

  14. Alkaline unwinding flow cytometry assay to measure nucleotide excision repair.

    PubMed

    Thyagarajan, Bharat; Anderson, Kristin E; Lessard, Christopher J; Veltri, Gregory; Jacobs, David R; Folsom, Aaron R; Gross, Myron D

    2007-03-01

    Nucleotide excision repair (NER), one of the DNA repair pathways, is the primary mechanism for repair of bulky adducts caused by physical and chemical agents, such as UV radiation, cisplatin and 4-nitroquinolones. Variations in DNA repair may be a significant risk factor for several cancers, but its measurement in epidemiological studies has been hindered by the high variability, complexity and laborious nature of currently available assays. An alkaline unwinding flow cytometric assay using UV-C radiation as a DNA-damaging agent was adapted for measurement of NER-mediated breaks. This assay was based on the principle of alkaline unwinding of strand breaks in double-stranded DNA to yield single-stranded DNA with the number of strand breaks being proportional to the amount of DNA damage. This assay measured 50,000 events per sample with several samples being analyzed per specimen, thereby providing very reliable measurements, which can be performed on a large-scale basis. Using area under the curve (AUC) to quantitate amount of NER-mediated breaks, this assay was able to detect increased NER-mediated breaks with increasing doses of UV-C radiation. The assay detected NER-mediated breaks in lymphocytes from normal donors and not in xeroderma pigmentosum lymphoblastoid cell lines indicating specificity for the detection of NER-mediated breaks. The assay measured NER-mediated breaks within G(1), S and G(2)/M phases of the cell cycle; thereby decreasing variability in measurements of NER-mediated breaks due to differences in cell cycle phases. Intraindividual variability for AUC after 120 min of repair was 15% with interindividual variability being approximately 43% for cells in the G(1) phase, indicating substantial between-subject variation and relatively low within-subject variation. Thus, the alkaline unwinding flow cytometry-based assay provides a high-throughput method for the specific measurement of NER-mediated breaks in lymphocytes.

  15. Diagnosis of eight groups of xeroderma pigmentosum by genetic complementation using recombinant adenovirus vectors.

    PubMed

    Yamashita, Toshiharu; Okura, Masae; Ishii-Osai, Yasue; Hida, Tokimasa

    2016-10-01

    Because patients with xeroderma pigmentosum (XP) must avoid ultraviolet (UV) light from an early age, an early diagnosis of this disorder is essential. XP is composed of seven genetic complementation groups, XP-A to -G, and a variant type (XP-V). To establish an easy and accurate diagnosis of the eight disease groups, we constructed recombinant adenoviruses that expressed one of the XP cDNA. When fibroblasts derived from patients with XP-A, -B, -C, -D, -F or -G were infected with the adenovirus expressing XPA, XPB, XPC, XPD, XPF or XPG, respectively, and UV-C at 5-20 J/m(2) was irradiated, cell viability was clearly recovered by the corresponding recombinant adenoviruses. In contrast, XP-E and XP-V cells were not significantly sensitive to UV irradiation and were barely complemented by the matched recombinant adenoviruses. However, co-infection of Ad-XPA with Ad-XPE increased survival rate of XP-E cells after UV-C exposure. When XP-V cell strains, including one derived from a Japanese patient, were infected with Ad-XPV, exposed to UV-B and cultured with 1 mmol/L of caffeine, flow cytometry detected a characteristic decrease in the S phase in all the XP-V cell strains. From these results, the eight groups of XP could be differentiated by utilizing a set of recombinant adenoviruses, indicating that our procedure provides a convenient and correct diagnostic method for all the XP groups including XP-E and XP-V.

  16. Impact of surface structure and feed gas composition on Bacillus subtilis endospore inactivation during direct plasma treatment

    PubMed Central

    Hertwig, Christian; Steins, Veronika; Reineke, Kai; Rademacher, Antje; Klocke, Michael; Rauh, Cornelia; Schlüter, Oliver

    2015-01-01

    This study investigated the inactivation efficiency of cold atmospheric pressure plasma treatment on Bacillus subtilis endospores dependent on the used feed gas composition and on the surface, the endospores were attached on. Glass petri-dishes, glass beads, and peppercorns were inoculated with the same endospore density and treated with a radio frequency plasma jet. Generated reactive species were detected using optical emission spectroscopy. A quantitative polymerase chain reaction (qPCR) based ratio detection system was established to monitor the DNA damage during the plasma treatment. Argon + 0.135% vol. oxygen + 0.2% vol. nitrogen as feed gas emitted the highest amounts of UV-C photons and considerable amount of reactive oxygen and nitrogen species. Plasma generated with argon + 0.135% vol. oxygen was characterized by the highest emission of reactive oxygen species (ROS), whereas the UV-C emission was negligible. The use of pure argon showed a negligible emission of UV photons and atomic oxygen, however, the emission of vacuum (V)UV photons was assumed. Similar maximum inactivation results were achieved for the three feed gas compositions. The surface structure had a significant impact on the inactivation efficiency of the plasma treatment. The maximum inactivation achieved was between 2.4 and 2.8 log10 on glass petri-dishes and 3.9 to 4.6 log10 on glass beads. The treatment of peppercorns resulted in an inactivation lower than 1.0 log10. qPCR results showed a significant DNA damage for all gas compositions. Pure argon showed the highest results for the DNA damage ratio values, followed by argon + 0.135% vol. oxygen + 0.2% vol. nitrogen. In case of argon + 0.135% vol. oxygen the inactivation seems to be dominated by the action of ROS. These findings indicate the significant role of VUV and UV photons in the inactivation process of B. subtilis endospores. PMID:26300855

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

    PubMed

    Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun; Kang, Dong-Hyun

    2015-07-10

    Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm(2). At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens.

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

    PubMed Central

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

    2015-01-01

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

  19. Prediction of biodegradability of aromatics in water using QSAR modeling.

    PubMed

    Cvetnic, Matija; Juretic Perisic, Daria; Kovacic, Marin; Kusic, Hrvoje; Dermadi, Jasna; Horvat, Sanja; Bolanca, Tomislav; Marin, Vedrana; Karamanis, Panaghiotis; Loncaric Bozic, Ana

    2017-05-01

    The study was aimed at developing models for predicting the biodegradability of aromatic water pollutants. For that purpose, 36 single-benzene ring compounds, with different type, number and position of substituents, were used. The biodegradability was estimated according to the ratio of the biochemical (BOD5) and chemical (COD) oxygen demand values determined for parent compounds ((BOD5/COD)0), as well as for their reaction mixtures in half-life achieved by UV-C/H2O2 process ((BOD5/COD)t1/2). The models correlating biodegradability and molecular structure characteristics of studied pollutants were derived using quantitative structure-activity relationship (QSAR) principles and tools. Upon derivation of the models and calibration on the training and subsequent testing on the test set, 3- and 5-variable models were selected as the most predictive for (BOD5/COD)0 and (BOD5/COD)t1/2, respectively, according to the values of statistical parameters R(2) and Q(2). Hence, 3-variable model predicting (BOD5/COD)0 possessed R(2)=0.863 and Q(2)=0.799 for training set, and R(2)=0.710 for test set, while 5-variable model predicting (BOD5/COD)1/2 possessed R(2)=0.886 and Q(2)=0.788 for training set, and R(2)=0.564 for test set. The selected models are interpretable and transparent, reflecting key structural features that influence targeted biodegradability and can be correlated with the degradation mechanisms of studied compounds by UV-C/H2O2.

  20. UV-Induced cell death in plants.

    PubMed

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

    2013-01-14

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

  1. Abatement of Polychoro-1,3-butadienes in Aqueous Solution by Ozone, UV Photolysis, and Advanced Oxidation Processes (O3/H2O2 and UV/H2O2).

    PubMed

    Lee, Minju; Merle, Tony; Rentsch, Daniel; Canonica, Silvio; von Gunten, Urs

    2017-01-03

    The abatement of 9 polychloro-1,3-butadienes (CBDs) in aqueous solution by ozone, UV-C(254 nm) photolysis, and the corresponding advanced oxidation processes (AOPs) (i.e., O3/H2O2 and UV/H2O2) was investigated. The following parameters were determined for 9 CBDs: second-order rate constants for the reactions of CBDs with ozone (kO3) (<0.1-7.9 × 10(3) M(-1) s(-1)) or with hydroxyl radicals (k(•)OH) (0.9 × 10(9) - 6.5 × 10(9) M(-1) s(-1)), photon fluence-based rate constants (k') (210-2730 m(2) einstein(-1)), and quantum yields (Φ) (0.03-0.95 mol einstein(-1)). During ozonation of CBDs in a natural groundwater, appreciable abatements (>50% at specific ozone doses of 0.5 gO3/gDOC to ∼100% at ≥1.0 gO3/gDOC) were achieved for tetra-CBDs followed by (Z)-1,1,2,3,4-penta-CBD and hexa-CBD. This is consistent with the magnitude of the determined kO3 and k(•)OH. The formation of bromate, a potentially carcinogenic ozonation byproduct, could be significantly reduced by addition of H2O2. For a typical UV disinfection dose (400 J/m(2)), various extents of phototransformations (10-90%) could be achieved. However, the efficient formation of photoisomers from CBDs with E/Z configuration must be taken into account because of their potential residual toxicity. Under UV-C(254 nm) photolysis conditions, no significant effect of H2O2 addition on CBDs abatement was observed due to an efficient direct phototransformation of CBDs.

  2. Fundamental molecules of life are pigments which arose and co-evolved as a response to the thermodynamic imperative of dissipating the prevailing solar spectrum

    NASA Astrophysics Data System (ADS)

    Michaelian, K.; Simeonov, A.

    2015-08-01

    The driving force behind the origin and evolution of life has been the thermodynamic imperative of increasing the entropy production of the biosphere through increasing the global solar photon dissipation rate. In the upper atmosphere of today, oxygen and ozone derived from life processes are performing the short-wavelength UV-C and UV-B dissipation. On Earth's surface, water and organic pigments in water facilitate the near-UV and visible photon dissipation. The first organic pigments probably formed, absorbed, and dissipated at those photochemically active wavelengths in the UV-C and UV-B that could have reached Earth's surface during the Archean. Proliferation of these pigments can be understood as an autocatalytic photochemical process obeying non-equilibrium thermodynamic directives related to increasing solar photon dissipation rate. Under these directives, organic pigments would have evolved over time to increase the global photon dissipation rate by (1) increasing the ratio of their effective photon cross sections to their physical size, (2) decreasing their electronic excited state lifetimes, (3) quenching radiative de-excitation channels (e.g., fluorescence), (4) covering ever more completely the prevailing solar spectrum, and (5) proliferating and dispersing to cover an ever greater surface area of Earth. From knowledge of the evolution of the spectrum of G-type stars, and considering the most probable history of the transparency of Earth's atmosphere, we construct the most probable Earth surface solar spectrum as a function of time and compare this with the history of molecular absorption maxima obtained from the available data in the literature. This comparison supports the conjecture that many fundamental molecules of life are pigments which arose, proliferated, and co-evolved as a response to dissipating the solar spectrum, supports the thermodynamic dissipation theory for the origin of life, constrains models for Earth's early atmosphere, and sheds

  3. Solar photocatalysis as disinfection technique: Inactivation of Klebsiella pneumoniae in sewage and investigation of changes in antibiotic resistance profile.

    PubMed

    Venieri, Danae; Gounaki, Iosifina; Bikouvaraki, Maria; Binas, Vassilios; Zachopoulos, Apostolos; Kiriakidis, George; Mantzavinos, Dionissios

    2016-06-14

    The presence of pathogenic microorganisms in wastewater and their resistant nature to antibiotics impose effective disinfection treatment for public health and environmental protection. In this work, photocatalysis with metal-doped titania under artificial and natural sunlight, chlorination and UV-C irradiation were evaluated for their potential to inactivate Klebsiella pneumoniae in real wastewater. Their overall effect on antibiotic resistance profile and target antibiotic resistance genes (ARGs) was also investigated. In particular, Mn-, Co- and binary Mn/Co-TiO2 were tested resulting in bacterial decrease from 4 to 6 Logs upon 90 min of exposure to simulated solar irradiation. The response of catalysts under natural solar light was insufficient, as only a 2 Log reduction was recorded even after 60 min of treatment. The relative activity of the applied methods for K. pneumoniae inactivation was decreased in the order: photocatalysis with the binary Co/Mn-TiO2 under artificial light > chlorination with dose of 5 mg/L of free chlorine > UV-C irradiation, at an initial bacterial concentration of 10(7) CFU/mL. The applied methods showed various effects on antibiotic resistance profile in residual cells. Among the tested antibiotics (ampicillin, cefaclor, sulfamethoxazole and tetracycline), considerable changes in MIC values were recorded for cefaclor and tetracycline. Resistance of surviving cells after treatment remained in high levels, reflecting the abundance of the corresponding target ARGs, namely tetA, tetM, sul1, blaTEM and ampC. The notable presence of target ARGs post disinfection raises concerns and makes wastewater effluent a carrier of antibiotic resistance elements into the aquatic environment.

  4. Visible optical radiation generates bactericidal effect applicable for inactivation of health care associated germs demonstrated by inactivation of E. coli and B. subtilis using 405-nm and 460-nm light emitting diodes

    NASA Astrophysics Data System (ADS)

    Hönes, Katharina; Stangl, Felix; Sift, Michael; Hessling, Martin

    2015-07-01

    The Ulm University of Applied Sciences is investigating a technique using visible optical radiation (405 nm and 460 nm) to inactivate health-hazardous bacteria in water. A conceivable application could be point-of-use disinfection implementations in developing countries for safe drinking water supply. Another possible application field could be to provide sterile water in medical institutions like hospitals or dental surgeries where contaminated pipework or long-term disuse often results in higher germ concentrations. Optical radiation for disinfection is presently mostly used in UV wavelength ranges but the possibility of bacterial inactivation with visible light was so far generally disregarded. One of the advantages of visible light is, that instead of mercury arc lamps, light emitting diodes could be used, which are commercially available and therefore cost-efficient concerning the visible light spectrum. Furthermore they inherit a considerable longer life span than UV-C LEDs and are non-hazardous in contrast to mercury arc lamps. Above all there are specific germs, like Bacillus subtilis, which show an inactivation resistance to UV-C wavelengths. Due to the totally different deactivation mechanism even higher disinfection rates are reached, compared to Escherichia coli as a standard laboratory germ. By 460 nm a reduction of three log-levels appeared with Bacillus subtilis and a half log-level with Escherichia coli both at a dose of about 300 J/cm². By the more efficient wavelength of 405 nm four and a half log-levels are reached with Bacillus subtilis and one and a half log-level with Escherichia coli also both at a dose of about 300 J/cm². In addition the employed optical setup, which delivered a homogeneous illumination and skirts the need of a stirring technique to compensate irregularities, was an important improvement compared to previous published setups. Evaluated by optical simulation in ZEMAX® the designed optical element provided proven

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

    NASA Astrophysics Data System (ADS)

    Horneck, G.

    2007-08-01

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

  6. Degradation of xenobiotics originating from the textile preparation, dyeing, and finishing industry using ozonation and advanced oxidation.

    PubMed

    Arslan-Alaton, Idil; Alaton, Izzet

    2007-09-01

    Effluents from textile preparation, dyeing, and finishing processes contain high concentrations of biologically difficult-to-degrade or even inert auxiliaries. Under these circumstances, it most often becomes inevitable to apply energy-intense and hence "imperative" treatment technologies (so-called advanced oxidation processes, AOPs) to achieve an acceptable reduction in the organic content of the effluent, thereby improving the biocompatibility of the originally refractory wastewater. The present experimental study focused on three problematic dyehouse effluent streams in order to alleviate the problem of toxicity and recalcitrance arising from the use of certain textile chemicals at source. For that purpose, the textile preparation stage was simulated by a nonionic surfactant (NS), the polyamide dyeing stage by a synthetic tannin (syntan; ST), and an aqueous biocidal finishing (BF) solution was employed to mimic typical textile finishing effluent. Synthetic effluent streams bearing NS, ST, or BF were subjected to treatment with different, well-established AOPs (ozonation at varying pH; advanced oxidation with H(2)O(2)/UV-C at varying H(2)O(2) concentrations) in order to degrade the active ingredients of the auxiliary formulations, thereby eliminating their toxicity and recalcitrance. Baseline experiments were conducted in order to optimize AOP conditions that were consecutively applied to observe changes in the originally poor effluent biodegradability and high toxicity. Obtained experimental findings revealed that (i) the COD content of NS could be reduced by at least 50% after H(2)O(2)/UV-C treatment at pH 9.0 accompanied by a nearly twofold improvement in its already fair biodegradability; (ii) the inhibitory effect of the biochemically reluctant ST on heterotrophic biomass was completely eliminated upon ozonation (dose=900 mg h(-1)) at pH 3.5; and (iii) the microbial toxicity exerted by BF totally disappeared after ozonation (dose=600 mg h(-1)) at pH 7

  7. Protective effect of deoxyribonucleosides on UV-irradiated human peripheral blood T-lymphocytes: possibilities for the selective killing of either cycling or non-cycling cells.

    PubMed

    Green, M H; Waugh, A P; Lowe, J E; Harcourt, S A; Clingen, P H; Cole, J; Arlett, C F

    1996-02-19

    Non-cycling human T-lymphocytes from normal subjects show a 10-fold greater sensitivity than fibroblasts to UV-B (280-315 nm) irradiation from a Westinghouse FS20 lamp, but only a 2.7-fold greater sensitivity to UV-C (254 nm) irradiation. Hypersensitivity is associated with a deficiency in the rejoining of excision breaks. Non-cycling T-lymphocytes have extremely low deoxyribonucleotide pools. Addition to the medium of the four deoxyribonucleosides, each at a concentration of 10(-5) M, substantially increases survival and reduces the persistence of excision-related strand breaks following UV-B or UV-C irradiation (Yew and Johnson (1979) Biochim. Biophys. Acta 562, 240-241; Green et al. (1994) Mutation Res., 315, 25-32). UV-resistance of T-lymphocytes is also increased by stimulating the cells into cycle. The addition of deoxyribonucleosides does not further enhance survival of cycling cells and they do not reach the level of resistance achieved by non-cycling cells in the presence of deoxyribonucleosides. We suggest that two opposing effects are in operation. Cells out of cycle can show increased resistance to DNA damage in the absence of division but they also have reduced deoxyribonucleotide pools, which may limit DNA repair. With UV-B irradiation, the exceptionally low dNTP pools in non-cycling T-lymphocytes cause this second effect to predominate. In contrast, with ionising radiation, which forms highly cytotoxic double-strand breaks, non-cycling human T-lymphocytes are slightly more resistant than fibroblasts. Non-cycling cells such as T-lymphocytes should be especially sensitive to agents which produce a high proportion of read excisable damage, but should show normal resistance to agents which highly toxic lesions. It may be possible by choice of DNA damaging agent and manipulation of cellular deoxyribonucleotide pools, to choose regimes which will selectively kill either cycling or non-cycling cells and to improve the efficacy of standard therapeutic

  8. Experimental Testing of Innovative Cold-Formed "GEB" Section / Badania Eksperymentalne Innowacyjnego Kształtownika Giętego Na Zimno Typu "Geb"

    NASA Astrophysics Data System (ADS)

    Łukowicz, Agnieszka; Urbańska-Galewska, Elżbieta; Gordziej-Zagórowska, Małgorzata

    2015-03-01

    One of the major advantages of light gauge steel structures made of cold-formed steel sections is their low weight so the production of typical single-storey steel structures of this kind of profiles is still rising. The well known profiles, e.o. Z-sections, C-sections and the so called hat-sections studied and described in the literature, are used mainly as purlins or truss components. A new profile GEB was patented for the use for primary load-bearing member in fabricated steel frames. According to the code [1] every novel cross section should be tested to assign the deformation shape and bearing capacity. The paper deals with the numerical and experimental research of bearing capacity of cold formed GEB profiles. The deformation shape and limit load was obtained from bending tests. The GEB cross section bearing capacity was also determined according to codes [1, 2]. Jedną z najważniejszych zalet lekkich konstrukcji metalowych, wytwarzanych z kształtowników giętych na zimno, jest ich mała masa, dlatego też, producenci coraz częściej wykorzystują możliwości profili giętych do wytwarzania typowych konstrukcji halowych w budownictwie systemowym. Proces gięcia na zimno, pozwala na formowanie różnego rodzaju przekrojów poprzecznych, które mogą być wykorzystywane jako elementy konstrukcji. Typowe kształty elementów. tzn. Z, C oraz tzw. przekroje kapeluszowe, które zostały przebadane i opisane w literaturze, wykorzystuje się głównie jako płatwie lub części składowe wiązarów kratowych. Nowo opatentowany przekrój typu GEB ma być wykorzystany jako element nośny konstrukcji ramowych. W związku z tym innowacyjny kształt oraz parametry geometryczne przekroju takiego kształtownika, związane z możliwością jego wyprodukowania oraz z warunkami nośności, stateczności oraz sztywności, muszą być optymalne. Według normy PN-EN 1993-1-3, każdy nowo uformowany przekrój powinien być przebadany pod kątem nośności elementu i formy

  9. Renovation of Shaft Mining Building No. 2 in Kłodawa Salt Mine/ Renowacja Budynku Nadszybia Nr 2 Na Terenie Kopalni Soli "Kłodawa" S.A.

    NASA Astrophysics Data System (ADS)

    Błaszczyński, Tomasz; Wielentejczyk, Przemysław

    2015-06-01

    The paper presents the renovation process of the shaft mining building No. 2 situated in the Kłodawa Salt Mine. A technical state of the facility required immediate reinforcement of structural elements, which was confirmed by expertise carried out by the authors. A lack of repairs could be the cause of building damage. The progress of corrosion in some steel profiles of columns or floors was very advanced. The state of the building was rapidly worsening due to the very high salinity of the indoor environment, moisture (building not insulated) and vibrating engines of machinery operating on different floors felt throughout the facility. After carrying out the technical expertise, working plans and specifications, and relevant numerical analysis, the modernization process was realized by the reinforcement or rebuilding of structural elements. Referat przedstawia sposób remontu i naprawy konstrukcji nośnej i obudowy budynku nadszybia nr 2 na terenie Kopalni Soli "Kłodawa". Elementy konstrukcyjne budynku wymagały natychmiastowego wzmocnienia, co potwierdziła ekspertyza wykonana przez autorów. Zaniechanie prac remontowych groziło awarią budowlaną pomimo przeprowadzonej wcześniej w 2002 r. naprawy. Postęp korozji w niektórych profilach stalowych słupów czy stropów był bardzo zaawansowany. Stan obiektu pogarszał się szybko ze względu na bardzo duże zasolenie środowiska, wilgoć (budynek nieocieplony) oraz pracujące na poszczególnych poziomach maszyny wytwarzające duże drgania wyczuwalne w każdym miejscu obiektu. Wykonano ekspertyzę i projekt wykonawczy przed przystąpieniem do prac renowacyjnych. Przeprowadzono stosowną analizę numeryczną budynku uwzględniając w obliczeniach osłabione korozją elementy pomniejszając odpowiednio w modelu ich parametry wytrzymałościowe. Na tej podstawie zaproponowano stosowne wzmocnienia. Zastosowano technologie wzmocnień stosując wymianę profili stalowych, wspawywanie dodatkowych profili lub blach

  10. [Birth weight of newborns and health behaviours and haematological parameters of pregnant women - results of preliminary studies].

    PubMed

    Suliga, Edyta; Adamczyk-Gruszka, Olga

    2015-12-15

    U osób urodzonych z małą masą ciała stwierdza się zwiększone ryzyko wystąpienia nadciśnienia tętniczego, dyslipidemii, chorób układu sercowo-naczyniowego, cukrzycy typu 2 w wieku dorosłym. U osób urodzonych z makrosomią również występuje zwiększone ryzyko późniejszego wystąpienia cukrzycy typu 2 i chorób sercowo-naczyniowych w wieku dorosłym. Bardzo ważne są więc badania służące zidentyfikowaniu czynników ryzyka zaburzeń wewnątrzmacicznego wzrastania płodu. Cel pracy. Celem pracy była ocena zależności między zachowaniami zdrowotnymi oraz wskaźnikami hematologicznymi kobiet ciężarnych a masą urodzeniową noworodków. Materiał i metody. Materiał badań stanowiły dane 274 kobiet i ich dzieci. Przy pomocy ankiety zebrano informacje na temat miejsca zamieszkania, wysokości i masy ciała, palenia papierosów oraz sposobu żywienia w czasie ciąży. Informacje dotyczące kolejności ciąży, przebiegu i czasu trwania ciąży oraz parametrów hematologicznych zebrano na podstawie analizy dokumentacji medycznej. Wyniki. Kobiety z niedowagą przed ciążą częściej rodziły dzieci z małą masą w stosunku do wieku płodowego, natomiast dzieci z dużą masą w stosunku do wieku płodowego częściej rodziły kobiety z nadwagą lub otyłością przed ciążą (p=0.0076) oraz te, u których stwierdzono w ciąży przyrost masy większy niż zalecany (p=0.0081). Matki, które urodziły dzieci z dużą masą w stosunku do wieku płodowego, częściej posiadały wyższe wartości wskaźników hematologicznych w pierwszym trymestrze ciąży w porównaniu z matkami dzieci o niższej masie w stosunku do wieku płodowego. Spożycie poszczególnych grup produktów przez matki w czasie ciąży nie różnicowało w istotny sposób masy urodzeniowej noworodków. Wnioski. Czynnikami istotnie różnicującymi wielkość urodzeniowej masy ciała w stosunku do wieku płodowego były BMI matki przed ciążą oraz całkowity przyrost masy w czasie

  11. Planes coordinates transformation between PSAD56 to SIRGAS using a Multilayer Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Tierra, Alfonso; Romero, Ricardo

    2014-12-01

    układów współrzędnych. W Ekwadorze wykorzystywany jest system PSAD56 (Provisional South American Datum 1956), ale w ostatnim czasie zaszła konieczność zdefi niowania wewnętrznego(krajowego) systemu SIRGAS (SIstema de Referencia Geocéntrico para las AmericaS). Do transformacji pomiędzy oboma systemami powszechnie wykorzystuje się metodę Helmerta, stosując układ siedmioparametrowy. Transformacja taka pozwala na zachowanie dokładności wystarczającej do opracowania map topografi cznych w skalach 1:25 000 lub mniejszych. W artykule do transformacji zastosowano sieci neuronowe, co umożliwiło podniesienie dokładności do skali 1:5 000

  12. a New Generation Mining Head with Disc Tool of Complex Trajectory / GŁOWICA URABIAJĄCA Nowej Generacji Z NARZĘDZIAMI Dyskowymi O ZŁOŻONEJ Trajektorii

    NASA Astrophysics Data System (ADS)

    Gospodarczyk, Piotr; Kotwica, Krzysztof; Stopka, Grzegorz

    2013-12-01

    In Polish underground mining plenty of dog headings are drilled with mechanical methods with the use of arm roadheaders equipped with milling units. Cutting tools applied on the units - rotary tangent bits in unfavourable mining and geological conditions or improper work conditions are affected by an accelerated wear process. It influences the speed and costs of drilling such excavations. The article presents a new and innovative solution of a mining head with asymmetric disc tools of complex trajectory elaborated at the Department of Mining, Dressing and Transport Machines, AGH University of Science and Technology, Krakow as an alternative for standard milling units. Advantages of the applied mining method using so called back incision were described as well as principles of construction and work of the suggested solution of the head. In order to work out a construction of the head prototype it was necessary to determine principles and guidelines based on laboratory tests. A construction of a specially prepared laboratory stand for examination of disc tools of complex trajectory, planned research methodology, course of tests and obtained results were presented. An analysis of the results allowed determining the above listed principles and guidelines for a construction of a prototype head. They were the base to work out, with cooperation of the REMAG Ltd Company in Katowice, a technical project of a new head solution, adapted for mounting on the arm of a medium arm roadheader KR 150. A constructed head underwent tests on a research stand on the REMAG testing area and received positive preliminary tests results. W polskim górnictwie podziemnym bardzo duża liczba wyrobisk korytarzowych drążona jest metodami mechanicznymi z wykorzystaniem ramionowych kombajnów chodnikowych, wyposażonych w organy frezujące. Stosowane na tych organach narzędzia skrawające - noże styczno-obrotowe, w niekorzystnych warunkach górniczo-geologicznych lub przy nieprawid

  13. Estimating Volume of Roof Fall in the Face of Longwall Mining by Using Numerical Methods / Estymacja Objętości Zawału Stropu W Rejonie Przodka Ścianowego W Oparciu O Metody Numeryczne

    NASA Astrophysics Data System (ADS)

    Saeedi, Gholamreza; Shahriar, Korosh; Rezai, Bahram

    2013-09-01

    Dilution is one of many challenges confronting professionals in mining and milling, and is perhaps one of the oldest. Longwall mining is one of the mining methods that is often affected by out-of-seam dilution (OSD). In this method, roof falls play a significant role in increasing OSD in the prop-free front of the face area. Thus, estimating the volume of roof fall can be extremely helpful to assess dilution of the run of mine coal without a sampling process. This paper presents the effect of exposed area geometry on potential roof falls using the 2D numerical modelling program FLAC. In this respect, a half-prolate ellipsoid was considered as the low stress level or plasticity zone under yield tension which roof material fall. Since FLAC software does not show roof falls in prop-free front of the face, a series of two-dimensional numerical models are developed using UDEC software. The comparison of the results of two numerical models clearly indicates that volumes of roof fall obtained by means of these methods are in good agreement with each other. Ścienianie warstw jest jednym z najpoważniejszych wyzwań stojących przed inżynierami górnikami i specjalistami z zakresu obróbki - jest to też jeden z najstarszych problemów. Wybieranie ścianowe jest metodą urabiania, w której często mamy do czynienia ze ścienianiem warstwy złoża. W metodzie tej strop odgrywa kluczową rolę w zapewnieniu stabilności w tych rejonach przodka, gdzie nie zastosowano obudów. Dlatego też estymacja objętości zawału stropu może być pomocna przy obliczaniu ścieniania warstwy węgla bez konieczności próbkowania. W artykule tym przeanalizowano wpływ geometrii powierzchni odkrytych na potencjalny zawał stropu przy użyciu metod modelowania numerycznego z wykorzystaniem oprogramowania FLAC. Uzyskano wydłużoną elipsoidę jako model strefy niskich naprężeń lub strefę plastyczności przed zawałem stropu. Ponieważ oprogramowanie FLAC nie pokazuje zawałów stropu w

  14. Determining the Optimum Cut-Off Grades in Sulfide Copper Deposits / Określanie Optymalnej Wartości Odcięcia Zawartości Procentowej Pierwiastka Użytecznego W Złożach Siarczku Miedzi

    NASA Astrophysics Data System (ADS)

    Rahimi, Esmaeil; Oraee, Kazem; Shafahi, Zia Aldin; Ghasemzadeh, Hasan

    2015-03-01

    maksymalizacja wartości bieżącej netto. Wyniki wskazują wpływ procesów ługowania na zawartość procentową pierwiastka użytecznego w rudzie pochodzącej z pierwotnych lub wtórnych złóż siarczku miedzi.

  15. Analysis of geodetic and legal documentation in the process of expropriation for roads. Krakow case study

    NASA Astrophysics Data System (ADS)

    Trembecka, Anna

    2013-06-01

    Amendment to the Act on special rules of preparation and implementation of investment in public roads resulted in an accelerated mode of acquisition of land for the development of roads. The decision to authorize the execution of road investment issued on its basis has several effects, i.e. determines the location of a road, approves surveying division, approves construction design and also results in acquisition of a real property by virtue of law by the State Treasury or local government unit, among others. The conducted study revealed that over 3 years, in this mode, the city of Krakow has acquired 31 hectares of land intended for the implementation of road investments. Compensation is determined in separate proceedings based on an appraisal study estimating property value, often at a distant time after the loss of land by the owner. One reason for the lengthy compensation proceedings is challenging the proposed amount of compensation, unregulated legal status of the property as well as imprecise legislation. It is important to properly develop geodetic and legal documentation which accompanies the application for issuance of the decision and is also used in compensation proceedings. Zmiana ustawy o szczególnych zasadach przygotowywania i realizacji inwestycji w zakresie dróg publicznych spowodowała przyspieszony tryb pozyskiwania gruntów przeznaczonych pod budowę dróg. Wydawana na jej podstawie decyzja o zezwoleniu na realizację inwestycji drogowej wywołuje szereg skutków, tj. m.in. ustala lokalizację drogi, zatwierdza podziały geodezyjne, zatwierdza projekt budowlany a także powoduje nabycie nieruchomości z mocy prawa, przez Skarb Państwa lub jednostki samorządu terytorialnego. Przeprowadzone badania wykazały iż w powyższym trybie miasto Kraków nabyło w okresie 3 lat ponad 31 ha gruntów przeznaczonych na realizację inwestycji drogowych. Odszkodowanie ustalane jest w drodze odrębnego postępowania w oparciu o operat szacunkowy okre

  16. [Effect of long-wave ultraviolet light (UV-A) and medium-wave ultraviolet rays (UV-B) on human skin. Critical comparison].

    PubMed

    Raab, W

    1980-04-15

    When discussing the effects of ultraviolet radiation on human skin, one should carefully distinguish between the long wave ultraviolet light (UV-A) and the short wave radiations (UV-B and UV-C). Ultraviolet A induces immediate pigmentation but, if high energies are applied, a permanent pigmentation is elicited. This type of ultraviolet A-induced pigmentation has been called "spontaneous" pigmentation as no erythematous reaction is necessary to induce or accelerate melanine formation. Ultraviolet B provokes erythema and consecutive pigmentation. Upon chronic exposure, ultraviolet B causes the wellknown actinic damage of the skin and even provokes carcinoma. With exposures to the sunlight (global radiation), one should be most careful. The public must be informed extensively about the dangers of excessive sunbaths. The use of artificial "suns" with spectra between 260 and 400 nm is limited as it may cause the same type of damage as the global radiation. An exact schedule for use of artificial lamps is strongly recommended. After one cycle of exposures, an interruption is necessary until the next cycle of irradiations may start. Upon continual use for tanning of the skin, artificial lamps may provoke irreversible damage of the skin. Radiation sources with emission spectra of wavelengths between 315 and 400 nm exclusively are well suited for the induction of skin pigmentation (cosmetic use). Potent radiation such as UVASUN systems provoke a "pleasant" permanent pigmentation after exposures for less than one hour. The use of ultraviolet A (UV-A) does not carry any risk for the human skin.

  17. Design and demonstration of ultra-wide bandgap AlGaN tunnel junctions

    SciTech Connect

    Zhang, Yuewei; Krishnamoorthy, Sriram; Akyol, Fatih; Allerman, Andrew A.; Moseley, Michael W.; Armstrong, Andrew M.; Rajan, Siddharth

    2016-09-19

    Ultra violet light emitting diodes (UV LEDs) face critical limitations in both the injection efficiency and the light extraction efficiency due to the resistive and absorbing p-type contact layers. In this work, we investigate the design and application of polarization engineered tunnel junctions for ultra-wide bandgap AlGaN (Al mole fraction >50%) materials towards highly efficient UV LEDs. We demonstrate that polarization-induced three dimensional charge is beneficial in reducing tunneling barriers especially for high composition AlGaN tunnel junctions. In addition, the design of graded tunnel junction structures could lead to low tunneling resistance below 10–3 Ω cm2 and low voltage consumption below 1 V (at 1 kA/cm2) for high composition AlGaN tunnel junctions. Experimental demonstration of 292 nm emission was achieved through non-equilibrium hole injection into wide bandgap materials with bandgap energy larger than 4.7 eV, and detailed modeling of tunnel junctions shows that they can be engineered to have low resistance and can enable efficient emitters in the UV-C wavelength range.

  18. Vortex Stabilized Plasma for Rapid Water Disinfection & Pharmaceutical Degradation

    NASA Astrophysics Data System (ADS)

    Hershcovitch, Ady

    2016-10-01

    Good quality drinking water is dwindling for large segments of the world population. Aggravating the problem is proliferation of antibiotics in the water supply, which give rise to drug resistant pathogens. One option for water supply increase is recycling waste and polluted water by inexpensive, environmentally friendly methods. Presently disinfection uses chemicals and UV radiation. Chemicals are limited by residual toxicity, while UV consumes much electricity. Current methods can remove only certain classes of drugs due to their large variety of physical and chemical properties. Plasmas in water are very attractive for degrading all pharmaceuticals and deactivating pathogens: intense arc current can physically break up any molecular bonds. UV radiation, ozone, etc. generation inside the water volume disinfects. Present utilized plasmas: glow, pulsed arcs are not power efficient; vortex stabilized plasmas are power efficient that can advance water treatment state-of-the-art by orders of magnitude. Proposed techniquefeatures novel components facilitating large diameter vortex stabilized in-water arcs with optimized plasma parameters for maximal UV-C emission; and harvests hydrogen centered by the vortex.

  19. Genetics of Lipid-Storage Management in Caenorhabditis elegans Embryos

    PubMed Central

    Schmökel, Verena; Memar, Nadin; Wiekenberg, Anne; Trotzmüller, Martin; Schnabel, Ralf; Döring, Frank

    2016-01-01

    Lipids play a pivotal role in embryogenesis as structural components of cellular membranes, as a source of energy, and as signaling molecules. On the basis of a collection of temperature-sensitive embryonic lethal mutants, a systematic database search, and a subsequent microscopic analysis of >300 interference RNA (RNAi)–treated/mutant worms, we identified a couple of evolutionary conserved genes associated with lipid storage in Caenorhabditis elegans embryos. The genes include cpl-1 (cathepsin L–like cysteine protease), ccz-1 (guanine nucleotide exchange factor subunit), and asm-3 (acid sphingomyelinase), which is closely related to the human Niemann-Pick disease–causing gene SMPD1. The respective mutant embryos accumulate enlarged droplets of neutral lipids (cpl-1) and yolk-containing lipid droplets (ccz-1) or have larger genuine lipid droplets (asm-3). The asm-3 mutant embryos additionally showed an enhanced resistance against C band ultraviolet (UV-C) light. Herein we propose that cpl-1, ccz-1, and asm-3 are genes required for the processing of lipid-containing droplets in C. elegans embryos. Owing to the high levels of conservation, the identified genes are also useful in studies of embryonic lipid storage in other organisms. PMID:26773047

  20. New optoelectronic sensor for measuring biologically effective irradiance

    NASA Astrophysics Data System (ADS)

    Kosyachenko, Leonid A.; Sklyarchuk, Valery M.

    1997-12-01

    A new optoelectronic sensor whose spectral responsivity to UV radiation is almost identical with that of the human skin or of the eyes is presented. The sensor comprises two closely-spaced UV-sensitive Au-SiC diode, one of which is fitted with a glass filter. The photodiodes are connected to electronics that amplifies, combines and subtracts electrical signals generated by radiation in the photodiodes. The responsivity of the Au-SiC diode structure with a semitransparent gold electrode covers the whole UV spectrum, with the long-wavelength end bounded by the semiconductor bandgap. The photodiode with a filter absorbing wavelengths shorter than 315-320 nm is responsive in the UV-A region, while the difference between the electrical signals generated in the filter-containing and filter-free diodes is determined by the UV-B + IV-C radiation. The measuring of biologically effective radiation over the entire UV spectral range is achieved through combining the signal generated by UV-A radiation and the previously amplified difference signal generated by UV-B + UV-C radiation. The sensor spectral responsivity thus obtained is very close to the tabular curve of the relative spectral effectiveness of UV radiation on the normal human skin or eyes.

  1. UV-resistant yeasts isolated from a high-altitude volcanic area on the Atacama Desert as eukaryotic models for astrobiology

    PubMed Central

    Pulschen, André A; Rodrigues, Fabio; Duarte, Rubens T D; Araujo, Gabriel G; Santiago, Iara F; Paulino-Lima, Ivan G; Rosa, Carlos A; Kato, Massuo J; Pellizari, Vivian H; Galante, Douglas

    2015-01-01

    The Sairecabur volcano (5971 m), in the Atacama Desert, is a high-altitude extreme environment with high daily temperature variations, acidic soils, intense UV radiation, and low availability of water. Four different species of yeasts were isolated from this region using oligotrophic media, identified and characterized for their tolerance to extreme conditions. rRNA sequencing revealed high identity (>98%) to Cryptococcus friedmannii, Exophiala sp., Holtermanniella watticus, and Rhodosporidium toruloides. To our knowledge, this is the first report of these yeasts in the Atacama Desert. All isolates showed high resistance to UV-C, UV-B and environmental-UV radiation, capacity to grow at moderate saline media (0.75–2.25 mol/L NaCl) and at moderate to cold temperatures, being C. friedmannii and H. watticus able to grow in temperatures down to −6.5°C. The presence of pigments, analyzed by Raman spectroscopy, correlated with UV resistance in some cases, but there is evidence that, on the natural environment, other molecular mechanisms may be as important as pigmentation, which has implications for the search of spectroscopic biosignatures on planetary surfaces. Due to the extreme tolerances of the isolated yeasts, these organisms represent interesting eukaryotic models for astrobiological purposes. PMID:26147800

  2. Direct Photolysis of Fluoroquinolone Antibiotics at 253.7 nm: Specific Reaction Kinetics and Formation of Equally Potent Fluoroquinolone Antibiotics.

    PubMed

    Snowberger, Sebastian; Adejumo, Hollie; He, Ke; Mangalgiri, Kiranmayi P; Hopanna, Mamatha; Soares, Ana Dulce; Blaney, Lee

    2016-09-06

    Three fluoroquinolone-to-fluoroquinolone antibiotic transformations were monitored during UV-C irradiation processes. In particular, the following reactions were observed: enrofloxacin-to-ciprofloxacin, difloxacin-to-sarafloxacin, and pefloxacin-to-norfloxacin. The apparent molar absorptivity and fluence-based pseudo-first-order rate constants for transformation of the six fluoroquinolones by direct photolysis at 253.7 nm were determined for the pH 2-12 range. These parameters were deconvoluted to calculate specific molar absorptivity and fluence-based rate constants for cationic, zwitterionic, and anionic fluoroquinolone species. For a typical disinfection fluence of 40 mJ/cm(2), the apparent transformation efficiencies were inflated by 2-8% when fluoroquinolone products were not considered; moreover, the overall transformation efficiencies at 400 mJ/cm(2) varied by up to 40% depending on pH. The three product antibiotics, namely ciprofloxacin, sarafloxacin, and norfloxacin, were found to be equally or more potent than the parent fluoroquinolones using an Escherichia coli-based assay. UV treatment of a solution containing difloxacin was found to increase antimicrobial activity due to formation of sarafloxacin. These results highlight the importance of considering antibiotic-to-antibiotic transformations in UV-based processes.

  3. UV radiation-induced biosynthesis, stability and antioxidant activity of mycosporine-like amino acids (MAAs) in a unicellular cyanobacterium Gloeocapsa sp. CU2556.

    PubMed

    Rastogi, Rajesh P; Incharoensakdi, Aran

    2014-01-05

    The biosynthesis of natural sunscreening compounds as influenced by ultraviolet radiation, their stability and antioxidant activity were studied in the cyanobacterium Gloeocapsa sp. CU-2556. An analysis by high-performance liquid chromatography (HPLC) with photodiode-array (PDA) detection revealed the biosynthesis of two MAAs, shinorine (UVλmax 333nm) and an unknown MAA designated as M-307 (UVλmax 307nm) with retention times of 5.9 and 6.4min, respectively. Induction of the synthesis of MAAs was studied under 395 (PAR), 320 (PAR+UV-A) and 295 (PAR+UV-A+UV-B) nm cut-off filters. MAAs induction was significantly increased with an increase in exposure time up to 72h in the samples covered with 295nm cut-off filters. Contrary to shinorine, the biosynthesis of M-307 was more dominant in this unicellular cyanobacterium. Both MAAs were highly stable to some physico-chemical stressors such as UV radiation, heat and a strong oxidizing agent. The MAA M-307 was more stable under strong oxidative stress than shinorine. Moreover, UV-C radiation drastically decreased the stability of both MAAs. The MAAs (shinorine+M-307) also exhibited efficient antioxidant activity which was dose-dependent. The results indicate that MAAs may perform a vital role in survival and sustainability of Gloeocapsa sp. CU-2556 in harsh environmental conditions by its ability to absorb/screen short wavelength UV radiation and antioxidant function.

  4. Alcohol-tolerant mutants of cyanobacterium Synechococcus elongatus PCC 7942 obtained by single-cell mutant screening system.

    PubMed

    Arai, Sayuri; Hayashihara, Kayoko; Kanamoto, Yuki; Shimizu, Kazunori; Hirokawa, Yasutaka; Hanai, Taizo; Murakami, Akio; Honda, Hiroyuki

    2017-04-12

    Enhancement of alcohol tolerance in microorganisms is an important strategy for improving bioalcohol productivity. Although cyanobacteria can be used as a promising biocatalyst to produce various alcohols directly from CO2 , low productivity and low tolerance against alcohols are the main issues to be resolved. Nevertheless, to date, a mutant with increasing alcohol tolerance has rarely been reported.n this study, we attempted to select isopropanol (IPA)-tolerant mutants of Synechococcus elongatus PCC 7942 using UV-C-induced random mutagenesis, followed by enrichment of the tolerant candidates in medium containing 10 g/L IPA and screening of the cells with a high growth rate in the single cell culture system in liquid medium containing 10 g/L IPA. We successfully acquired the most tolerant strain, SY1043, which maintains the ability to grow in medium containing 30 g/L IPA. The photosynthetic oxygen-evolving activities of SY1043 were almost same in cells after 72-h incubation under light with or without 10 g/L IPA, while the activity of the wild-type was remarkably decreased after the incubation with IPA. SY1043 also showed higher tolerance to ethanol, 1-butanol, isobutanol, and 1-pentanol than the wild type. These results suggest that SY1043 would be a promising candidate to improve alcohol production using cyanobacteria. This article is protected by copyright. All rights reserved.

  5. Annual solar UV exposure and biological effective dose rates on the Martian surface.

    PubMed

    Patel, M R; Bérces, A; Kerékgyárto, T; Rontó, Gy; Lammer, H; Zarnecki, J C

    2004-01-01

    The ultraviolet (UV) environment of Mars has been investigated to gain an understanding of the variation of exposure throughout a Martian year, and link this flux to biological effects and possible survival of organisms at the Martian surface. To gain an idea of how the solar UV radiation varies between different regions, including planned landing sites of two future Mars surface missions, we modelled the total solar UV surface flux throughout one Martian year for two different dust scenarios. To understand the degree of solar UV stress on micro-organisms and/or molecules essential for life on the surface of Mars, we also calculated the biologically effective dose (BED) for T7 and Uracil in relevant wavelength regions at the Martian surface as a function of season and latitude, and discuss the biological survival rates in the presence of Martian solar UV radiation. High T7/Uracil BED ratios indicate that even at high latitudes where the UV flux is significantly reduced, the radiation environment is still hostile for life due to the persisting UV-C component of the flux.

  6. Synthesis, physical properties and application of the zero-valent iron/titanium dioxide heterocomposite having high activity for the sustainable photocatalytic removal of hexavalent chromium in water.

    PubMed

    Petala, Eleni; Baikousi, Maria; Karakassides, Michael A; Zoppellaro, Giorgio; Filip, Jan; Tuček, Jiří; Vasilopoulos, Konstantinos C; Pechoušek, Jiří; Zbořil, Radek

    2016-04-21

    A magnetic photocatalytic material composed of nanoscale zero-valent iron (nZVI) homogeneously distributed over a mesoporous nanocrystalline TiO2 matrix has been prepared by a multistage chemical process, including sol-gel technique, wet impregnation, and chemical reduction. X-ray powder diffraction and Raman spectroscopy were used for the structural and chemical characterization of the magnetic photocatalyst, while bulk magnetization measurements and scanning/transmission electron microscopy were employed to determine the physical and textural properties of the photocatalyst. The synthesized nZVI@TiO2 photocatalyst shows very high efficiency in the removal of hexavalent chromium, Cr(vi), from water. The degradation rate follows a pseudo-first-order kinetic model. Most importantly, the remarkable efficiency of the photocatalyst is found to be due to the synergistic contributions of both counterparts, nZVI and TiO2, as validated by comparative experiments with neat TiO2 and nZVI@TiO2 under UV-C irradiation and without irradiation. New insights into the mechanism of synergistic degradation of chromium(vi) and suppressed oxidation of nZVI particles in the composite material are proposed and therein discussed.

  7. Photocatalytic transformation of acesulfame: Transformation products identification and embryotoxicity study.

    PubMed

    Li, Adela Jing; Schmitz, Oliver J; Stephan, Susanne; Lenzen, Claudia; Yue, Patrick Ying-Kit; Li, Kaibin; Li, Huashou; Leung, Kelvin Sze-Yin

    2016-02-01

    Artificial sweeteners have been recognized as emerging contaminants due to their wide application, environmental persistence and ubiquitous occurrence. Among them, acesulfame has attracted much attention. After being discharged into the environment, acesulfame undergoes photolysis naturally. However, acesulfame photodegradation behavior and identity of its transformation products, critical to understanding acesulfame's environmental impact, have not been thoroughly investigated. The present study aimed to fill this knowledge gap by a laboratory simulation study in examining acesulfame transformation products and pathways under UV-C photolysis in the presence of TiO2. Photodegradation products of acesulfame were isolated and analyzed using the LC-IM-QTOF-MS coupled with LC Ion Trap MS in the MS(n) mode. Our results show six new transformation products that have not been previously identified. The molecular structures and transformation pathways were proposed. Further embryotoxicity tests showed that acesulfame transformation products at the low g L(-1) level produced significant adverse effects in tail detachment, heart rate, hatching rate and survival rate during fish embryo development. The identification of additional transformation products with proposed transformation pathways of acesulfame, the increased toxicity of acesulfame after photolysis, and the fact that the accumulation of acesulfame transformation products is increasingly likely make acesulfame contamination even more important. Water resource control agencies need to consider legislation regarding acesulfame and other artificial sweeteners, while further studies are carried out, in order to protect the safety of this most vital resource.

  8. Photochromic and self-cleaning properties of TiO2-AgCl/TiO2-xCu thin film.

    PubMed

    Sangchay, Weerachai; Sikong, Lek; Kooptarnond, Kalayanee

    2013-02-01

    The TiO2-AgCl/TiO2-xCu thin films were prepared by sol-gel method and dip coated on glass slide. The prepared films were synthesized at the temperature of 400 degrees C for 2 h with a heating rate of 10 degrees C/min. The microstructure and properties of synthesized TiO2-AgCl/TiO2-xCu thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic forced microscope and UV-vis diffuse reflectance spectroscopy. Finally, the hydrophilic property was evaluated by means of contact angle of water droplet on the films. The results show all samples have film thickness in range of 400-500 nm and their surfaces are dense and strong with a large surface area according to the image of atomic forced microscope. It can be noted that TiO2-AgCl/TiO2-5Cu thin films exhibit the highest photochromic (or the lowest capability of light transmittance) at 250-400 nm. The TiO2-AgCl/TiO2-xCu thin films can block UV C, UV B and UV A rays and exhibit self-cleaning effect (small contact angle, 3.9 degrees ) under UV irradiation.

  9. Computational and experimental determinations of the UV adsorption of polyvinylsilsesquioxane-silica and titanium dioxide hybrids.

    PubMed

    Wang, Haiyan; Lin, Derong; Wang, Di; Hu, Lijiang; Huang, Yudong; Liu, Li; Loy, Douglas A

    2014-01-01

    Sunscreens that absorb UV light without photodegradation could reduce skin cancer. Polyvinyl silsesquioxanes are known to have greater thermal and photochemical stability than organic compounds, such as those in sunscreens. This paper evaluates the UV transparency of vinyl silsesquioxanes (VS) and its hybrids with SiO2(VSTE) and TiO2(VSTT) experimentally and computationally. Based on films of VS prepared by sol-gel polymerization, using benzoyl peroxide as an initiator, vinyltrimethoxysilane (VMS) formulated oligomer through thermal curing. Similarly, VSTE films were prepared from VMS and 5-25 wt-% tetraethoxysilane (TEOS) and VSTT films were prepared from VMS and 5-25 wt-% titanium tetrabutoxide (TTB). Experimental average transparencies of the modified films were found to be about 9-14% between 280-320 nm, 67-73% between 320-350nm, and 86-89% between 350-400nm. Computation of the band gap was absorption edges for the hybrids in excellent agreement with experimental data. VS, VSTE and VSTT showed good absorption in UV-C and UV-B range, but absorbed virtually no UV-A. Addition of SiO2 or TiO2 does not improve UV-B absorption, but on the opposite increases transparency of thin films to UV. This increase was validated with molecular simulations. Results show computational design can predict better sunscreens and reduce the effort of creating sunscreens that are capable of absorbing more UV-B and UV-A.

  10. Fenton and photo-Fenton treatment of a synthetic tannin used in leather tannery: a multi-approach study.

    PubMed

    Lofrano, G; Meriç, S; Belgiorno, V; Nikolaou, A; Napoli, R M A

    2007-01-01

    The aim of this work was to compare the behaviour of Fenton and photo-Fenton (UV-A, UV-C) processes to treat synthetic tannin (syntan) used in leather tannery which is one of the most polluting industries, releasing many xenobiotics. Both oxidation processes were performed at pH 3.0 and temperature 40-45 degrees C, which is the original temperature of the re-tanning process, in synthetic solutions containing 100 and 300 mg/L of COD equivalent of syntan. The efficiency of the applied oxidation processes was monitored by chemical oxygen demand (COD), oxidation redox potential (ORP) and aromaticity (UV280) and double bond (UV254) absorbance measurements. Acute toxicity test on Daphnia magna was performed to monitor toxicity in untreated and treated syntan solution. Gas chromatography-mass spectrometry (GC-MS) was applied to identify by-products of partial oxidation occurring in treated samples. The effective ratio of H2O2/FeSO4 for photo-Fenton processes was found to be feasible in terms of reagents used in the process.

  11. Effect of ultraviolet light on toxicity of the PAH fluoranthene to freshwater organisms

    SciTech Connect

    Brooke, L.T.; Cox, D.; Kahl, M.; Spehar, R.L.

    1994-12-31

    Certain polyaromatic hydrocarbons (PAHs) can be activated by irradiation with ultraviolet light in the near UV waveband to increase their biocidal qualities. Fluoranthene is one of the PAHs that has this capacity. Ten species of freshwater animals and one species of freshwater plant were acutely exposed to several concentrations of fluoranthene in the presence of additional UV light and to standard light conditions. Tests were conducted using flow-through static or renewal techniques. Fluoranthene concentrations were measured using high pressure liquid chromatography. UV light was produced by UV-emitting fluorescent lamps. UV-C was removed from the spectrum by cellulose triacetate filters. Separate measurements were made of spectral ranges 310 to 390, 265 to 328 and < 320 nm. All species tested except for a dragonfly, Ophiogomphus sp. were more sensitive to fluoranthene in the presence of UV light ranging from 449 to 926 {mu}W/CM{sup 2} than the same species exposed to this chemical in tests using standard light conditions. Sensitivity increased by factors of {<=}32 times in these tests. Two species were tested for effects of UV light during chronic exposure. The cladoceran, Daphnia magna, showed a 17.1 fold increase in sensitivity to fluoranthene due to UV light and the fathead minnow showed a 5.77 fold increase. Results show that water quality criteria for fluoranthene should be adjusted for UV light effects.

  12. Efficiency of hydroxyl radical formation and phenol decomposition using UV light emitting diodes and H2O2.

    PubMed

    Vilhunen, Sari; Puton, Jarosław; Virkutyte, Jurate; Sillanpää, Mika

    2011-01-01

    A novel process combining hydrogen peroxide (H2O2) and radiation emitted by ultraviolet light emitting diodes (UV LEDs) has been investigated. The UV LEDs were used as UV-C light sources emitting radiation in the range 257-277 nm for decomposition of the model substance phenol in water. In addition, the effect of H2O2 to phenol molar ratio and initial phenol concentration was examined. Two parameters, the decomposition efficiency of phenol and characterization of hydroxyl radical (HO*) production from H2O2 when illuminated with UV radiation, were selected to provide detailed information regarding the performance of the UV LEDs in the treatment process. A new concept was introduced to characterize and describe the production of HO* radicals produced when photons were absorbed by H2O2 molecules. The phenol decomposition efficiency at the initial concentration of 100 mg/L was the most pronounced at the lowest emitted wavelength. A significant correlation was found between the phenol decomposition efficiency and the photons absorbed by H2O2 (i.e. formation of radicals).

  13. Comparative Study on the Efficacy of Bacteriophages, Sanitizers, and UV Light Treatments To Control Listeria monocytogenes on Sliced Mushrooms (Agaricus bisporus).

    PubMed

    Murray, Kayla; Wu, Fan; Aktar, Rafia; Namvar, Azadeh; Warriner, Keith

    2015-06-01

    The following reports on a comparative study on the efficacy of different decontamination technologies to decrease Listeria monocytogenes inoculated onto white sliced mushrooms and assesses the fate of residual levels during posttreatment storage under aerobic conditions at 8 °C. The treatments were chemical (hydrogen peroxide, peroxyacetic acid, ozonated water, electrolyzed water, chitosan, lactic acid), biological (Listeria bacteriophages), and physical (UV-C, UV-hydrogen peroxide). None of the treatments achieved >1.2 log CFU reduction in L. monocytogenes levels; bacteriophages at a multiplicity of infection of 100 and 3% (vol/vol) hydrogen peroxide were the most effective of the treatments tested. However, growth of residual L. monocytogenes during posttreatment storage attained levels equal to or greater than levels in the nontreated controls. The growth of L. monocytogenes was inhibited on mushrooms treated with chitosan, electrolyzed water, peroxyacetic acid, or UV. Yet, L. monocytogenes inoculated onto mushrooms and treated with UV-hydrogen peroxide decreased during posttreatment storage, through a combination of sublethal injury and dehydration of the mushroom surface. Although mushrooms treated with UV-hydrogen peroxide became darker during storage, the samples were visually acceptable relative to controls. In conclusion, of the treatments evaluated, UV-hydrogen peroxide holds promise to control L. monocytogenes on mushroom surfaces.

  14. Disinfection potential of ozone, ultraviolet-C and their combination in wash water for the fresh-cut vegetable industry.

    PubMed

    Selma, María V; Allende, Ana; López-Gálvez, Francisco; Conesa, María A; Gil, María I

    2008-09-01

    The purpose of this research was to investigate the disinfection efficacy of ozone (O(3)) and UV-C illumination (UV), and their combination (O(3)-UV) for reducing microbial flora of fresh-cut onion, escarole, carrot, and spinach wash waters collected from the industry. Furthermore, the influence of water physicochemical parameters on the decontamination efficacy and the effect of these technologies on physicochemical quality of wash water were analyzed. O(3), UV, and O(3)-UV were effective disinfection treatments on vegetable wash water, with a maximum microbial reduction of 6.6 log CFU mL(-1) after 60 min treatment with O(3)-UV. However, maximum total microbial reductions achieved by UV and O(3) treatments after 60 min were 4.0 and 5.9 log CFU mL(-1), lower than by O(3)-UV treatment. Furthermore, turbidity of wash water was reduced significantly by O(3) and O(3)-UV treatments, while UV treatment did not affect the physicochemical quality of the water. Conclusions derived from this study illustrate that O(3) and O(3)-UV are alternatives to other sanitizers used in the fresh-cut washing processes. The use of these technologies would allow less frequent changing of spent water and the use of much lower sanitizer doses. Nevertheless, in specific applications such as carrot wash water, where levels of undesirable microbial and chemical constituents are lower than other vegetable wash water, UV treatment could be an appropriate treatment considering cost-effectiveness criteria.

  15. The isolation and mapping of a novel hydroxycinnamoyltransferase in the globe artichoke chlorogenic acid pathway

    PubMed Central

    Comino, Cinzia; Hehn, Alain; Moglia, Andrea; Menin, Barbara; Bourgaud, Frédéric; Lanteri, Sergio; Portis, Ezio

    2009-01-01

    Background The leaves of globe artichoke and cultivated cardoon (Cynara cardunculus L.) have significant pharmaceutical properties, which mainly result from their high content of polyphenolic compounds such as monocaffeoylquinic and dicaffeoylquinic acid (DCQ), and a range of flavonoid compounds. Results Hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase (HQT) encoding genes have been isolated from both globe artichoke and cultivated cardoon (GenBank accessions DQ915589 and DQ915590, respectively) using CODEHOP and PCR-RACE. A phylogenetic analysis revealed that their sequences belong to one of the major acyltransferase groups (anthranilate N-hydroxycinnamoyl/benzoyltransferase). The heterologous expression of globe artichoke HQT in E. coli showed that this enzyme can catalyze the esterification of quinic acid with caffeoyl-CoA or p-coumaroyl-CoA to generate, respectively, chlorogenic acid (CGA) and p-coumaroyl quinate. Real time PCR experiments demonstrated an increase in the expression level of HQT in UV-C treated leaves, and established a correlation between the synthesis of phenolic acids and protection against damage due to abiotic stress. The HQT gene, together with a gene encoding hydroxycinnamoyl-CoA:shikimate/quinate hydroxycinnamoyltransferase (HCT) previously isolated from globe artichoke, have been incorporated within the developing globe artichoke linkage maps. Conclusion A novel acyltransferase involved in the biosynthesis of CGA in globe artichoke has been isolated, characterized and mapped. This is a good basis for our effort to understand the genetic basis of phenylpropanoid (PP) biosynthesis in C. cardunculus. PMID:19292932

  16. "Stockpile" of Slight Transcriptomic Changes Determines the Indirect Genotoxicity of Low-Dose BPA in Thyroid Cells.

    PubMed

    Porreca, Immacolata; Ulloa Severino, Luisa; D'Angelo, Fulvio; Cuomo, Danila; Ceccarelli, Michele; Altucci, Lucia; Amendola, Elena; Nebbioso, Angela; Mallardo, Massimo; De Felice, Mario; Ambrosino, Concetta

    2016-01-01

    Epidemiological and experimental data highlighted the thyroid-disrupting activity of bisphenol A (BPA). Although pivotal to identify the mechanisms of toxicity, direct low-dose BPA effects on thyrocytes have not been assessed. Here, we report the results of microarray experiments revealing that the transcriptome reacts dynamically to low-dose BPA exposure, adapting the changes in gene expression to the exposure duration. The response involves many genes, enriching specific pathways and biological functions mainly cell death/proliferation or DNA repair. Their expression is only slightly altered but, since they enrich specific pathways, this results in major effects as shown here for transcripts involved in the DNA repair pathway. Indeed, even though no phenotypic changes are induced by the treatment, we show that the exposure to BPA impairs the cell response to further stressors. We experimentally verify that prolonged exposure to low doses of BPA results in a delayed response to UV-C-induced DNA damage, due to impairment of p21-Tp53 axis, with the BPA-treated cells more prone to cell death and DNA damage accumulation. The present findings shed light on a possible mechanism by which BPA, not able to directly cause genetic damage at environmental dose, may exert an indirect genotoxic activity.

  17. Investigation of light output uniformity and performance using a UV transmitting glass optic for a multi-UV LED array

    NASA Astrophysics Data System (ADS)

    Jasenak, Brian; Willsey, Rachel; Willsey, Adam; Forish, James

    2016-03-01

    Ultraviolet light-emitting diode (UV LED) adoption is accelerating; they are being used in new applications such as UV curing, germicidal irradiation, nondestructive testing, and forensic analysis. In many of these applications, it is critically important to produce a uniform light distribution and consistent surface irradiance. Flat panes of fused quartz, silica, or glass are commonly used to cover and protect multi-UV LED arrays. However, they don't offer the advantages of an optical lens design. An investigation was conducted to determine the effect of a secondary glass optic on the uniformity of the light distribution and irradiance. Glass optics capable of transmitting UV-A, UV-B, and UV-C wavelengths can improve light distribution and intensity. In this study, a UV transmitting glass formulation and secondary linear optic were designed and manufactured to demonstrate their effects on achievable irradiance intensity and uniformity. Prismatic patterning on the light source surface of the lens was used to minimize reflection losses on the incident surface of the glass. Fresnel optics were molded into the opposite side of the UV transmitting glass to control the refraction of the light and to gain the desired light intensity distribution from two multi-UV LED arrays. A 20% increase in relative irradiance was observed while maintaining the same coverage area. This work discusses the optical design and the resulting benefits of controlled light output on UV LED systems, which include reduced driving current, decreased thermal deterioration, improved energy efficiency, and longer LED lifetime.

  18. Photoactive TiO2 coatings obtained by Plasma Electrolytic Oxidation in refrigerated electrolytes

    NASA Astrophysics Data System (ADS)

    Franz, Silvia; Perego, Daniele; Marchese, Ottavia; Lucotti, Andrea; Bestetti, Massimiliano

    2016-11-01

    The effect of synthesis conditions on the properties of nanoporous TiO2 coatings obtained by PEO in refrigerated electrolytes have been investigated. Linear sweep voltammetry was carried out on the TiO2 coatings, in dark and under UV-C irradiation, in order to assess the photoelectrochemical behavior of samples. The largest photocurrents (0.18 mA/cm2) were measured on TiO2 coatings obtained by PEO in refrigerated aqueous solutions. UV-vis spectra revealed that lowering the processing temperature from 20 to -3.5 °C induced a blue-shift of the absorption band of the TiO2 coatings from 3.05 to 3.42 eV. The main advantage of PEO in refrigerated aqueous solutions over current approaches, based on anodic oxidation and thermal treatments, is that the synthesis of photoactive TiO2 coatings can be carried out in a relatively easy, quick and reproducible way, without annealing pre- and post-treatments. Furthermore, by controlling the solution temperature in PEO process, the photocurrent of the resulting TiO2 coating reaches quite high values.

  19. Influence of ultraviolet radiation on calf thymus DNA studied by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Tang, Yulong; Guo, Zhouyi

    2005-01-01

    In order to assess the mutagenic effects of ultraviolet (UV) and solar irradiation on DNA, Raman spectroscopy is used to investigate the structural changes of calf thymus DNA in aqueous solution after ultraviolet radiation. The damage to DNA induced by UV is usually carried out with a germicidal lamp, which mainly covers the region of UVC. For the sake of making a complete investigation of the damage to DNA by ultraviolet radiation, we use different intervals of UV (UVA, UVB and UVC) to conduct our experiments. Such UV radiation is obtained from a solar UV simulator (SS) made by us, which can be conveniently adjusted to different wavelengths and radiation intensities. From the comparison of the Raman spectra of DNA in aqueous solution before and after ultraviolet radiation, it can be inferred that the UV-C has a serious influence on the DNA molecular conformation and damages the hydrogen bonds and bases, UV-B only damages the DNA molecular structure to some extent while UV-A almost does not play an impact on the DNA molecular conformation. For all the three regions of UV, the damage increases with the elongation of irradiation time and is first observed in pyrimidine-dimer bases and deoxyribose. The experimental results also partly support the formation of several types of dimeric lesions between adjacent pyrimidine bases, most notably cyclobutane pyrimidine dimers (CPDs) and the Dewar valence isomers.

  20. Characterization of the survival ability of Cupriavidus metallidurans and Ralstonia pickettii from space-related environments.

    PubMed

    Mijnendonckx, K; Provoost, A; Ott, C M; Venkateswaran, K; Mahillon, J; Leys, N; Van Houdt, R

    2013-02-01

    Four Cupriavidus metallidurans and eight Ralstonia pickettii isolates from the space industry and the International Space Station (ISS) were characterized in detail. Nine of the 12 isolates were able to form a biofilm on plastics and all were resistant to several antibiotics. R. pickettii isolates from the surface of the Mars Orbiter prior to flight were 2.5 times more resistant to UV-C(254nm) radiation compared to the R. pickettii type strain. All isolates showed moderate to high tolerance against at least seven different metal ions. They were tolerant to medium to high silver concentrations (0.5-4 μM), which are higher than the ionic silver disinfectant concentrations measured regularly in the drinking water aboard the ISS. Furthermore, all isolates survived a 23-month exposure to 2 μM AgNO(3) in drinking water. These resistance properties are putatively encoded by their endogenous megaplasmids. This study demonstrated that extreme resistance is not required to withstand the disinfection and sterilization procedures implemented in the ISS and space industry. All isolates acquired moderate to high tolerance against several stressors and can grow in oligotrophic conditions, enabling them to persist in these environments.

  1. Molecular and cellular analysis of the DNA repair defect in a patient in Xeroderma pigmentosum complementation group D who has the clinical features of Xeroderma pigmentosum and Cockayne syndrome

    SciTech Connect

    Broughton, B.C.; Thompson, A.F.; Harcourt, S.A.; Cole, J.; Arlett, C.F.; Lehmann, A.R.; Vermeulen, W.; Hoeijmakers, J.H.J.; Botta, E.; Stefanini, M.

    1995-01-01

    Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are quite distinct genetic disorders that are associated with defects in excision repair of UV-induced DNA damage. A few patients have been described previously with the clinical features of both disorders. In this paper we describe an individual in this category who has unusual cellular responses to UV light. We show that his cultured fibroblasts and lymphocytes are extremely sensitive to irradiation with UV-C, despite a level of nucleotide excision repair that is 30%-40% that of normal cells. The deficiency is assigned to the XP-D complementation group, and we have identified two causative mutations in the XPD gene: a gly{yields}arg change at amino acid 675 in the allele inherited from the patient`s mother and a -1 frameshift at amino acid 669 in the allele inherited from his father. These mutations are in the C-terminal 20% of the 760-amino-acid XPD protein, in a region where we have recently identified several mutations in patients with trichothiodystrophy. 44 refs., 5 figs., 2 tabs.

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

    PubMed

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

    2015-09-23

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

  3. Photoprotective bioactivity present in a unique marine bacteria collection from Portuguese deep sea hydrothermal vents.

    PubMed

    Martins, Ana; Tenreiro, Tania; Andrade, Gonçalo; Gadanho, Mário; Chaves, Sandra; Abrantes, Marta; Calado, Patrícia; Tenreiro, Rogério; Vieira, Helena

    2013-05-10

    Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea hydrothermal vents near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR vents collection in natural product synthesis with market applications.

  4. Accumulation of a bioactive triterpene saponin fraction of Quillaja brasiliensis leaves is associated with abiotic and biotic stresses.

    PubMed

    de Costa, Fernanda; Yendo, Anna Carolina Alves; Fleck, Juliane Deise; Gosmann, Grace; Fett-Neto, Arthur Germano

    2013-05-01

    The saponins from leaves of Quillaja brasiliensis, a native species from Southern Brazil, show structural and functional similarities to those of Quillaja saponaria barks, which are currently used as adjuvants in vaccine formulations. The accumulation patterns of an immunoadjuvant fraction of leaf triterpene saponins (QB-90) in response to stress factors were examined, aiming at understanding the regulation of accumulation of these metabolites. The content of QB-90 in leaf disks was significantly increased by application of different osmotic stress agents, such as sorbitol, sodium chloride and polyethylene glycol in isosmotic concentrations. Higher yields of bioactive saponins were also observed upon exposure to salicylic acid, jasmonic acid, ultrasound and UV-C light. Experiments with shoots indicated a significant increase in QB-90 yields with moderate increases in white light irradiance and by mechanical damage applied to leaves. The increased accumulation of these terpenes may be part of a defense response. The results herein described may contribute to further advance knowledge on the regulation of accumulation of bioactive saponins, and at defining strategies to improve yields of these useful metabolites.

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

    NASA Astrophysics Data System (ADS)

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

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

  6. Pathogen control in complex fluids with water-coupled excimer lamps at 282 and 308 nm.

    PubMed

    Coogan, John J

    2005-01-01

    Water-coupled excimer lamp systems have been developed to inactivate microorganisms within complex, low-optical quality, fluids. Monochromatic lamps were selected to minimize UV-B and UV-C absorption within the carrier fluids while maximizing deposition within specific chemical targets. Fundamentals, system scaling and power supply design are discussed. This work used two large-surface area excimer lamps as intense sources of near monochromatic radiation at 308 and 282 nm. Data are presented for two distinct fluid systems: flow-through processing of large-volume metalworking fluids used in heavy industry and batch irradiation of human blood plasma and platelet suspensions used in transfusion medicine. In the first, a 200-600 L/min reactor is used to control bacterial concentrations within metalworking fluids used in large-scale metal machining processes. Control is defined as the maintenance of 10(3) to 10(4) CFU/mL in fluids that without treatment would have concentrations over 10(7) CFU/mL. The second is a batch process for viral inactivation in undiluted blood bank products. Samples of fresh frozen plasma and platelet suspensions were spiked with high titers of porcine parvovirus (PPV) and irradiated at 308 and 282 nm. Although both wavelengths were effective at reducing PPV levels, 308 nm light resulted in both higher rates of viral inactivation (greater than 6 log units) and lower rates of fluid degradation.

  7. A review and investigation of the effect of nanophotocatalytic ozonation process for phenolic compound removal from real effluent of pulp and paper industry.

    PubMed

    Biglari, Hamed; Afsharnia, Mojtaba; Alipour, Vali; Khosravi, Rasoul; Sharafi, Kiomars; Mahvi, Amir Hossein

    2017-02-01

    Phenol and its derivatives are the major environmental pollutants discharged from paper and pulp industries into water bodies. All these compounds and chlorinated phenolic compounds in particular are very toxic to fauna and flora, even at relatively low concentration. This study aimed to investigate the removal rate of phenolic compounds from the effluent of pulp and paper industries using a combination of ozonation and photocatalytic processes. Firstly, a certain volume from the effluent of paper and pulp industries containing certain phenol concentrations was obtained and fed into a prefabricated reactor at laboratory scale. Then, the combined and separate effects of zinc oxide dosage (ZnO), ozone flow rate (O3), and pH under ultra violet radiation for 30 min were evaluated. The concentration of phenolic compounds and the produced ozone gas flow rate were measured by a spectrophotometry and iodometric method, respectively. The results showed that the phenolic removal rate increased at acidic PHs compared with alkaline PHs; it was also decreased with the increase in ZnO dosages. Furthermore, the highest phenolic compound's removal rate was 99% at the optimal condition (pH 5, ZnO dosage of 0.1 g L(-1) at the 30 min with UV-C illumination of 125 W). Finally, Daphnia toxicity test showed that treated effluent was safe and met the standards to the extent that it can be discharged into the receiving waters. Graphical abstract ᅟ.

  8. Transcription of Satellite III non-coding RNAs is a general stress response in human cells

    PubMed Central

    Valgardsdottir, Rut; Chiodi, Ilaria; Giordano, Manuela; Rossi, Antonio; Bazzini, Silvia; Ghigna, Claudia; Riva, Silvano; Biamonti, Giuseppe

    2008-01-01

    In heat-shocked human cells, heat shock factor 1 activates transcription of tandem arrays of repetitive Satellite III (SatIII) DNA in pericentromeric heterochromatin. Satellite III RNAs remain associated with sites of transcription in nuclear stress bodies (nSBs). Here we use real-time RT-PCR to study the expression of these genomic regions. Transcription is highly asymmetrical and most of the transcripts contain the G-rich strand of the repeat. A low level of G-rich RNAs is detectable in unstressed cells and a 104-fold induction occurs after heat shock. G-rich RNAs are induced by a wide range of stress treatments including heavy metals, UV-C, oxidative and hyper-osmotic stress. Differences exist among stressing agents both for the kinetics and the extent of induction (>100- to 80.000-fold). In all cases, G-rich transcripts are associated with nSBs. On the contrary, C-rich transcripts are almost undetectable in unstressed cells and modestly increase after stress. Production of SatIII RNAs after hyper-osmotic stress depends on the Tonicity Element Binding Protein indicating that activation of the arrays is triggered by different transcription factors. This is the first example of a non-coding RNA whose transcription is controlled by different transcription factors under different growth conditions. PMID:18039709

  9. Ultralow-threshold electrically injected AlGaN nanowire ultraviolet lasers on Si operating at low temperature.

    PubMed

    Li, K H; Liu, X; Wang, Q; Zhao, S; Mi, Z

    2015-02-01

    Ultraviolet laser radiation has been adopted in a wide range of applications as diverse as water purification, flexible displays, data storage, sterilization, diagnosis and bioagent detection. Success in developing semiconductor-based, compact ultraviolet laser sources, however, has been extremely limited. Here, we report that defect-free disordered AlGaN core-shell nanowire arrays, formed directly on a Si substrate, can be used to achieve highly stable, electrically pumped lasers across the entire ultraviolet AII (UV-AII) band (∼320-340 nm) at low temperatures. The laser threshold is in the range of tens of amps per centimetre squared, which is nearly three orders of magnitude lower than those of previously reported quantum-well lasers. This work also reports the first demonstration of electrically injected AlGaN-based ultraviolet lasers monolithically grown on a Si substrate, and offers a new avenue for achieving semiconductor lasers in the ultraviolet B (UV-B) (280-320 nm) and ultraviolet C (UV-C) (<280 nm) bands.

  10. UV-resistant yeasts isolated from a high-altitude volcanic area on the Atacama Desert as eukaryotic models for astrobiology

    NASA Astrophysics Data System (ADS)

    Pulschen, A. A.; Rodrigues, F.; Duarte, R. T.; Araujo, G. G.; Santiago, I. F.; Paulino-Lima, Ivan G.; Rosa, Carlos A.; Kato, Massuo J.; Pellizari, Vivian H.; Galante, Douglas

    2015-08-01

    The Sairecabur volcano (5971 m), in the Atacama Desert, is a high-altitude extreme environment with high daily temperature variations, acidic soils, intense UV radiation, and low availability of water. Four different species of yeasts were isolated from this region using oligotrophic media, identified and characterized for their tolerance to extreme conditions. rRNA sequencing revealed high identity (>98%) to Cryptococcus friedmannii, Exophiala sp., Holtermanniella watticus, and Rhodosporidium toruloides. To our knowledge, this is the first report of these yeasts in the Atacama Desert. All isolates showed high resistance to UV-C, UV-B and environmental-UV radiation, capacity to grow at moderate saline media (0.75-2.25 mol/L NaCl) and at moderate to cold temperatures, being C. friedmannii and H. watticus able to grow in temperatures down to -6.5°C. The presence of pigments, analyzed by Raman spectroscopy, correlated with UV resistance in some cases, but there is evidence that, on the natural environment, other molecular mechanisms may be as important as pigmentation, which has implications for the search of spectroscopic biosignatures on planetary surfaces. Due to the extreme tolerances of the isolated yeasts, these organisms represent interesting eukaryotic models for astrobiological purposes.

  11. Evaluation of DNA damage reversal during medium-pressure UV disinfection.

    PubMed

    Poepping, Christopher; Beck, Sara E; Wright, Harold; Linden, Karl G

    2014-06-01

    Ultraviolet (UV) disinfection relies on the principal that DNA exposure to UV irradiation leads to the formation of cytotoxic lesions resulting in the inactivation of microorganisms. Cyclobutane pyrimdine dimers (CPDs) account for the majority of DNA lesions upon UV exposure. Past research has demonstrated reversal of CPDs in extracted DNA formed at high UV-C wavelength irradiation (280 nm) upon subsequent irradiation at lower UVC wavelengths (230-240 nm). Medium-pressure (MP) UV lamps produce a polychromatic emission giving rise to the possibility that cellular DNA in a target pathogen may undergo simultaneous damage and repair when exposed to multiple wavelengths during the disinfection process, decreasing the efficiency of MP UV lamp disinfection. Culture techniques and a quantitative polymerase chain reaction (qPCR) assay were used to examine cell viability and DNA damage reversal. qPCR results indicated direct photoreversal of UV-induced DNA damage through sequential irradiations of 280 nm followed by 228 nm in Escherichia coli DNA. However, significant photoreversal was only observed after high initial doses and secondary doses of UV light. The doses where significant photoreversal took place were more than 10 times higher than those typically used in UV disinfection. Despite evidence of CPD photoreversal, bacterial growth assays showed no indication that sequential-wavelength irradiations result in higher survival rates than single-wavelength irradiations.

  12. Improvement of Biological Indicators by Uniformly Distributing Bacillus subtilis Spores in Monolayers To Evaluate Enhanced Spore Decontamination Technologies

    PubMed Central

    Raguse, Marina; Fiebrandt, Marcel; Stapelmann, Katharina; Madela, Kazimierz; Laue, Michael; Lackmann, Jan-Wilm; Thwaite, Joanne E.; Setlow, Peter; Awakowicz, Peter

    2016-01-01

    Novel decontamination technologies, including cold low-pressure plasma and blue light (400 nm), are promising alternatives to conventional surface decontamination methods. However, the standardization of the assessment of such sterilization processes remains to be accomplished. Bacterial endospores of the genera Bacillus and Geobacillus are frequently used as biological indicators (BIs) of sterility. Ensuring standardized and reproducible BIs for reliable testing procedures is a significant problem in industrial settings. In this study, an electrically driven spray deposition device was developed, allowing fast, reproducible, and homogeneous preparation of Bacillus subtilis 168 spore monolayers on glass surfaces. A detailed description of the structural design as well as the operating principle of the spraying device is given. The reproducible formation of spore monolayers of up to 5 × 107 spores per sample was verified by scanning electron microscopy. Surface inactivation studies revealed that monolayered spores were inactivated by UV-C (254 nm), low-pressure argon plasma (500 W, 10 Pa, 100 standard cubic cm per min), and blue light (400 nm) significantly faster than multilayered spores were. We have thus succeeded in the uniform preparation of reproducible, highly concentrated spore monolayers with the potential to generate BIs for a variety of nonpenetrating surface decontamination techniques. PMID:26801572

  13. Ultraviolet spectrophotometry of flares on ``quiescent'' M and K dwarf exoplanet hosts

    NASA Astrophysics Data System (ADS)

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

    We present an analysis of a sample of flares on ``quiescent'' (i.e. non-flare) M and K stars using temporally resolved UV spectroscopy from the growing body of MUSCLES Treasury Survey data. Specifically, our analysis quantified the response of the far-UV C II, Si III, Si IV, and N V emission lines and the far-UV continuum during the flares. Using these tracers, we examined one representative event on GJ 832. In concordance with flares recorded on the Sun and AD Leo, the MUSCLES flares are well fit by a power law relationship of similar slope in frequency versus energy. Flares can strip atmospheric mass from orbiting planets, adversely affecting their long-term habitability. To gauge the amplitude of this effect, we computed an energy-balance upper-limit on the amount of atmosphere a large flare might remove from an orbiting Earth due purely to elevated EUV flux and found this limit to be modest relative to Earth's atmospheric mass.

  14. Desert Cyanobacteria under simulated space and Martian conditions

    NASA Astrophysics Data System (ADS)

    Billi, D.; Ghelardini, P.; Onofri, S.; Cockell, C. S.; Rabbow, E.; Horneck, G.

    2008-09-01

    3 mm of Antarctic sandstone, were exposed in EVT-E1 to vacuum conditions (10-5Pa for 1 week), 50 freezethaw cycles (-20 to 20 °C for 2 weeks), UV-C (254 nm, at 10, 100 and 1000 J/ m2) and total UV (200-400 nm, at 1.5, 1.5x103, and 1.5x105 kJ/ m2). In EVT-E2 samples were tested in CO2 Mars atmosphere in presence and absence of total UV (200-400 nm, at 1.5x105 kJ/ m2). In exposed cells subcellular damage was evaluated in situ by using membrane integrity and redox related probes along and by evaluating autofluorescence of the photosynthetic pigments. While the genome was evaluated by assessing its suitability as template in polymerase chain reaction (PCR)-based assays, e.g. random amplification of polymorphic DNA (RAPD) with primers derived from repetitive sequences present in cyanobacterial genomes and gene locus amplification. In addition, the colony forming ability of exposed cells was evaluated. Chroococcidiopsis CCMEE 123 survived to all EVTE1 and EVT-E2 as suggested by intact plasmatic membrane integrity, unbleached pigments, respiration capability upon rewetting and colony forming ability. Nevertheless, DNA damage occurred in cells exposed to vacuum, freeze-thaw cycles, 1000 J/m2 (UV-C) and 1.5x103 and 1.5x105 kJ/ m2 (total UV radiation), as revealed by the failure of PCR-based assays. Whereas virtually identical PCR profiles were yielded from controls and cells exposed to lower doses of UV-C radiation (10 and 100 J/m2 ) and total UV radiation (1.5 kJ/m2). Chroococcidiopsis CCMEE 134 exposed to EVT-E1 and EVT-E2 exhibited membrane integrity, photosynthetic pigments autofluorescence and dehydrogenase activity, but were unable to form colonies. Moreover, only cells exposed to 10 and 100 J/m2 (UV-C) were positive to PCR-based analysis, although they yielded altered RAPD profiles. Even though the synergistic action of vacuum and UV radiation was not investigated, these results highlighted an extraordinary survival potential of dried cells of Chroococcidiopsis

  15. Shade avoidance 6 encodes an Arabidopsis flap endonuclease required for maintenance of genome integrity and development

    PubMed Central

    Zhang, Yijuan; Wen, Chunhong; Liu, Songbai; Zheng, Li; Shen, Binghui; Tao, Yi

    2016-01-01

    Flap endonuclease-1 (FEN1) belongs to the Rad2 family of structure-specific nucleases. It is required for several DNA metabolic pathways, including DNA replication and DNA damage repair. Here, we have identified a shade avoidance mutant, sav6, which reduces the mRNA splicing efficiency of SAV6. We have demonstrated that SAV6 is an FEN1 homologue that shows double-flap endonuclease and gap-dependent endonuclease activity, but lacks exonuclease activity. sav6 mutants are hypersensitive to DNA damage induced by ultraviolet (UV)-C radiation and reagents that induce double-stranded DNA breaks, but exhibit normal responses to chemicals that block DNA replication. Signalling components that respond to DNA damage are constitutively activated in sav6 mutants. These data indicate that SAV6 is required for DNA damage repair and the maintenance of genome integrity. Mutant sav6 plants also show reduced root apical meristem (RAM) size and defective quiescent centre (QC) development. The expression of SMR7, a cell cycle regulatory gene, and ERF115 and PSK5, regulators of QC division, is increased in sav6 mutants. Their constitutive induction is likely due to the elevated DNA damage responses in sav6 and may lead to defects in the development of the RAM and QC. Therefore, SAV6 assures proper root development through maintenance of genome integrity. PMID:26721386

  16. Human repair endonuclease incises DNA at cytosine photoproducts

    SciTech Connect

    Gallagher, P.E.; Weiss, R.B.; Brent, T.P.; Duker, N.J.

    1987-05-01

    The nature of DNA damage by uvB and uvC irradiation was investigated using a defined sequence of human DNA. A UV-irradiated, 3'-end-labeled, 92 base pair sequence from the human alphoid segment was incubated with a purified human lymphoblast endonuclease that incises DNA at non-dimer photoproducts. Analysis by polyacrylamide gel electrophoresis identified all sites of endonucleolytic incision as cytosines. These were found in regions of the DNA sequence lacking adjacent pyrimidines and therefore are neither cyclobutane pyrimidine dimers nor 6-4'-pyrimidines. Incision at cytosine photoproducts was not detected at loci corresponding to alkali-labile sites in either control or irradiated substrates. This demonstrates that the bands detected after the enzymic reactions were not the result of DNA strand breaks, base loss sites or ring-opened cytosines. The optimal wavelengths for formation of cytosine photoproducts are 270-295 nm, similar to those associated with maximal tumor yields in animal ultraviolet carcinogenesis studies. Irradiation by monochromatic 254 nm light resulted in reduced cytosine photoproduct formation. This human UV endonuclease has an apparently identical substrate specificity to E. coli endonuclease III. Both the human and bacterial enzymes incise cytosine moieties in UV irradiated DNA and modified thymines in oxidized DNA.

  17. Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation.

    PubMed Central

    Harlow, G R; Jenkins, M E; Pittalwala, T S; Mount, D W

    1994-01-01

    A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage. PMID:8148646

  18. Enhanced inactivation of E. coli and MS-2 phage by silver ions combined with UV-A and visible light irradiation.

    PubMed

    Kim, Jee Yeon; Lee, Changha; Cho, Min; Yoon, Jeyong

    2008-01-01

    Silver ions have been widely used as an effective water disinfectant or antimicrobial material for many decades. In addition, the application of silver ions in combination with other biocides, especially UV(254) (UV-C) irradiation, was reported to be effective in enhancing its germicidal activity. However, it is not yet known how UV-A (300-400 nm) or visible light irradiation, which have little or no antimicrobial activities, affect microorganism inactivation by silver ions. This study newly reports that the inactivation efficiencies of Escherichia coli and MS-2 phage by silver ions were significantly enhanced by UV-A or visible light irradiation. UV-A irradiation enhanced the inactivation of E. coli and MS-2 phage by 3.0 and 2.5 log/30 min, respectively, as compared with the simple summated value of individual applications of silver ions and UV-A. A similar trend was observed with visible light irradiation (>400 nm) although the level of enhancement was lessened. The photochemical reaction of silver-cysteine complex was suggested as a possible mechanism for this enhancement. Spectrophotometric and MALDI-TOF mass analyses support the fact that silver ions coupled with light irradiation causes critical cell damage through the complexation of silver ions with thiol (-SH) groups in structural or enzymatic proteins of the microorganisms and their subsequent photochemical destruction.

  19. Apaf-1-deficient fog mouse cell apoptosis involves hypo-polarization of the mitochondrial inner membrane, ATP depletion and citrate accumulation.

    PubMed

    Katoh, Iyoko; Sato, Shingo; Fukunishi, Nahoko; Yoshida, Hiroki; Imai, Takasuke; Kurata, Shun-Ichi

    2008-12-01

    To explore how the intrinsic apoptosis pathway is controlled in the spontaneous fog (forebrain overgrowth) mutant mice with an Apaf1 splicing deficiency, we examined spleen and bone marrow cells from Apaf1(+/+) (+/+) and Apaf1(fog/fog) (fog/fog) mice for initiator caspase-9 activation by cellular stresses. When the mitochondrial inner membrane potential (Deltapsim) was disrupted by staurosporine, +/+ cells but not fog/fog cells activated caspase-9 to cause apoptosis, indicating the lack of apoptosome (apoptosis protease activating factor 1 (Apaf-1)/cytochrome c/(d)ATP/procaspase-9) function in fog/fog cells. However, when a marginal ( approximately 20%) decrease in Deltapsim was caused by hydrogen peroxide (0.1 mM), peroxynitritedonor 3-morpholinosydnonimine (0.1 mM) and UV-C irradiation (20 J/m(2)), both +/+ and fog/fog cells triggered procaspase-9 auto-processing and its downstream cascade activation. Supporting our previous results, procaspase-9 pre-existing in the mitochondria induced its auto-processing before the cytosolic caspase activation regardless of the genotypes. Cellular ATP concentration significantly decreased under the hypoactive Deltapsim condition. Furthermore, we detected accumulation of citrate, a kosmotrope known to facilitate procaspase-9 dimerization, probably due to a feedback control of the Krebs cycle by the electron transfer system. Thus, mitochondrial in situ caspase-9 activation may be caused by the major metabolic reactions in response to physiological stresses, which may represent a mode of Apaf-1-independent apoptosis hypothesized from recent genetic studies.

  20. Conformational space and photochemistry of alpha-terpinene.

    PubMed

    Marzec, K M; Reva, I; Fausto, R; Malek, K; Proniewicz, L M

    2010-05-06

    Alpha-terpinene is a natural product that is isolated from a variety of plant sources and is used in the pharmaceutical and perfume industries. In the atmosphere, under the influence of sunlight, alpha-terpinene undergoes a series of photochemical transformations and contributes to the formation of the secondary organic aerosols. In the present work, alpha-terpinene has been isolated in low-temperature xenon and argon matrices, and its structure and photochemistry were characterized with the aid of FTIR spectroscopy and DFT calculations. The theory predicts three conformers resulting from the rotation of the exocyclic CH(CH(3))(2) framework, that is, Trans (T) and Gauche (G+ and G-) forms. The two Gauche conformers were estimated to be higher in energy, by ca. 1.75 kJ mol(-1), than the most stable Trans form. The signatures of all three conformers were found to be present in the experimental low-temperature matrix spectra with the T form dominating in diluted matrices. The conformational ratio was found to shift in favor of the G+/G- forms upon annealing of the matrices as well as in the neat alpha-terpinene liquid. UV-C (lambda > 235 nm) irradiation of matrix-isolated alpha-terpinene led to its isomerization into an open-ring species, which is produced in the Z configuration and in the conformations that require the smallest structural rearrangements of both the reagent and matrix.

  1. “Stockpile” of Slight Transcriptomic Changes Determines the Indirect Genotoxicity of Low-Dose BPA in Thyroid Cells

    PubMed Central

    Porreca, Immacolata; Ulloa Severino, Luisa; D’Angelo, Fulvio; Cuomo, Danila; Ceccarelli, Michele; Altucci, Lucia; Amendola, Elena; Nebbioso, Angela; Mallardo, Massimo

    2016-01-01

    Epidemiological and experimental data highlighted the thyroid-disrupting activity of bisphenol A (BPA). Although pivotal to identify the mechanisms of toxicity, direct low-dose BPA effects on thyrocytes have not been assessed. Here, we report the results of microarray experiments revealing that the transcriptome reacts dynamically to low-dose BPA exposure, adapting the changes in gene expression to the exposure duration. The response involves many genes, enriching specific pathways and biological functions mainly cell death/proliferation or DNA repair. Their expression is only slightly altered but, since they enrich specific pathways, this results in major effects as shown here for transcripts involved in the DNA repair pathway. Indeed, even though no phenotypic changes are induced by the treatment, we show that the exposure to BPA impairs the cell response to further stressors. We experimentally verify that prolonged exposure to low doses of BPA results in a delayed response to UV-C-induced DNA damage, due to impairment of p21-Tp53 axis, with the BPA-treated cells more prone to cell death and DNA damage accumulation. The present findings shed light on a possible mechanism by which BPA, not able to directly cause genetic damage at environmental dose, may exert an indirect genotoxic activity. PMID:26982218

  2. Degradation of microcystin toxins in a falling film photocatalytic reactor with immobilized titanium dioxide catalyst.

    PubMed

    Shephard, Gordon S; Stockenström, Sonja; de Villiers, David; Engelbrecht, Willem J; Wessels, Gabriël F S

    2002-01-01

    The increasing incidence of algal blooms in fresh water supplies and the consequent possibility of cyanobacterial microcystin contamination of potable water is a cause of recent concern. Heterogeneous photocatalytic oxidation forms part of a family of advanced water treatment technologies comprising the generation of reactive oxidizing species in water media and results in the complete oxidative degradation (mineralization) of organic pollutants to yield carbon dioxide, water and inorganic ions. A new experimental laboratory-scale 'falling film' reactor has been developed to study the photocatalytic degradation of microcystins in aqueous solution. The reactor consisted of a fiberglass sheet impregnated with immobilized titanium dioxide (TiO2) catalyst over which the microcystin solution was pumped (as a falling film) while being irradiated from UV-C germicidal lamps. The design of the system obviated the necessity to separate suspended catalyst from treated water as required in slurry reactors. The photocatalytic degradation was characterized by pseudo-first order reaction kinetics. Rapid degradation of microcystins LR, YR and RR was observed in natural lake water with half lives less than 10 min, while even faster rates were achieved in laboratory distilled water. Although low pH (pH 3) marginally improved reaction rates. the presence of radical scavengers such as sulfate ions was detrimental to the photocatalytic oxidation process.

  3. Kinetics of heterogeneous photocatalytic degradation of reactive dyes in an immobilized TiO2 photocatalytic reactor.

    PubMed

    Mahmoodi, Niyaz Mohammad; Arami, Mokhtar; Limaee, Nargess Yousefi; Tabrizi, Nooshin Salman

    2006-03-01

    The photocatalytic degradation of two reactive dyes has been investigated by UV/TiO2/H2O2 using an immobilized TiO2 photocatalytic reactor. Reactive Blue 8 (RB 8) and Reactive Blue 220 (RB 220) textile dyes were used as model compounds. Photocatalytic degradation processes were performed using a 5-L solution containing dyes. The initial concentrations of dyes were 50 mg/L. The radiation source was two 15 W UV-C lamps. A batch mode immersion photocatalytic reactor was utilized. UV-vis and ion chromatography (IC) analyses were employed to obtain the details of the photodegradation of the selected dyes. Colored synthetic waters were completely decolorized in relatively short time after UV irradiation in the presence of various concentrations of hydrogen peroxide. Formate, acetate, oxalate, and glyoxylate anions were detected as dominant aliphatic intermediates where they were further oxidized slowly to CO2. The UV/TiO2/H2O2 process was able to oxidize the dyes with partial mineralization of carbon, nitrogen, and sulfur heteroatoms into CO2, NO3-, and SO4(2-), respectively. Kinetics analysis indicates that the photocatalytic decolorization rates of the dye can be approximated by a pseudo-first-order model. The UV/TiO2/H2O2 process proved to be capable of decolorization and mineralization of the reactive dyes (RB 8 and RB 220).

  4. A platform analytical quality by design (AQbD) approach for multiple UHPLC-UV and UHPLC-MS methods development for protein analysis.

    PubMed

    Kochling, Jianmei; Wu, Wei; Hua, Yimin; Guan, Qian; Castaneda-Merced, Juan

    2016-06-05

    A platform analytical quality by design approach for methods development is presented in this paper. This approach is not limited just to method development following the same logical Analytical quality by design (AQbD) process, it is also exploited across a range of applications in methods development with commonality in equipment and procedures. As demonstrated by the development process of 3 methods, the systematic approach strategy offers a thorough understanding of the method scientific strength. The knowledge gained from the UHPLC-UV peptide mapping method can be easily transferred to the UHPLC-MS oxidation method and the UHPLC-UV C-terminal heterogeneity methods of the same protein. In addition, the platform AQbD method development strategy ensures method robustness is built in during development. In early phases, a good method can generate reliable data for product development allowing confident decision making. Methods generated following the AQbD approach have great potential for avoiding extensive post-approval analytical method change. While in the commercial phase, high quality data ensures timely data release, reduced regulatory risk, and lowered lab operational cost. Moreover, large, reliable database and knowledge gained during AQbD method development provide strong justifications during regulatory filling for the selection of important parameters or parameter change needs for method validation, and help to justify for removal of unnecessary tests used for product specifications.

  5. Transcriptome Characterization of Gnetum parvifolium Reveals Candidate Genes Involved in Important Secondary Metabolic Pathways of Flavonoids and Stilbenoids

    PubMed Central

    Deng, Nan; Chang, Ermei; Li, Minghe; Ji, Jing; Yao, Xiamei; Bartish, Igor V.; Liu, Jianfeng; Ma, Jing; Chen, Lanzhen; Jiang, Zeping; Shi, Shengqing

    2016-01-01

    Gnetum is a small, unique group of Gnetophyta with a controversial phylogenetic position. Gnetum parvifolium is an important Chinese traditional medicinal plant, which is rich in bioactive compounds such as flavonoids and stilbenoids. These compounds provide significant medicinal effects, mostly as antioxidant, anticancer, and antibacterial agents. However, the mechanisms involved in the biosynthesis and regulation of these compounds in G. parvifolium are still unknown. In this study, we found that flavonoids and stilbene compounds accumulated at different levels in various tissues of G. parvifolium. We further obtained and analyzed massive sequence information from pooled samples of G. parvifolium by transcriptome sequencing, which generated 94,816 unigenes with an average length of 724 bp. Functional annotation of all these unigenes revealed that many of them were associated with several important secondary metabolism pathways including flavonoids and stilbenoids. In particular, several candidate unigenes (PAL-, C4H-, 4CL-, and STS-like genes) involved in stilbenoids biosynthesis were highly expressed in leaves and mature fruits. Furthermore, high temperature and UV-C strongly induced the expression of these genes and enhanced stilbene production (i.e., resveratrol and piceatannol) in leaves of young seedlings. Our present transcriptomic and biochemical data on secondary metabolites in G. parvifolium should encourage further investigation on evolution, ecology, functional genomics, and breeding of this plant with strong pharmaceutical potential. PMID:26973657

  6. UV damage of collagen: insights from model collagen peptides.

    PubMed

    Jariashvili, Ketevan; Madhan, Balaraman; Brodsky, Barbara; Kuchava, Ana; Namicheishvili, Louisa; Metreveli, Nunu

    2012-03-01

    Fibrils of Type I collagen in the skin are exposed to ultraviolet (UV) light and there have been claims that collagen photo-degradation leads to wrinkles and may contribute to skin cancers. To understand the effects of UV radiation on collagen, Type I collagen solutions were exposed to the UV-C wavelength of 254 nm for defined lengths of time at 4°C. Circular dichroism (CD) experiments show that irradiation of collagen leads to high loss of triple helical content with a new lower thermal stability peak and SDS-gel electrophoresis indicates breakdown of collagen chains. To better define the effects of UV radiation on the collagen triple-helix, the studies were extended to peptides which model the collagen sequence and conformation. CD studies showed irradiation for days led to lower magnitudes of the triple-helix maximum at 225 nm and lower thermal stabilities for two peptides containing multiple Gly-Pro-Hyp triplets. In contrast, the highest radiation exposure led to little change in the T(m) values of (Gly-Pro-Pro)(10) and (Ala-Hyp-Gly)(10) , although (Gly-Pro-Pro)(10) did show a significant decrease in triple helix intensity. Mass spectroscopy indicated preferential cleavage sites within the peptides, and identification of some of the most susceptible sites of cleavage. The effect of radiation on these well defined peptides gives insight into the sequence and conformational specificity of photo-degradation of collagen.

  7. Degradation of methyl orange using short-wavelength UV irradiation with oxygen microbubbles.

    PubMed

    Tasaki, Tsutomu; Wada, Tsubasa; Fujimoto, Kanji; Kai, Shinji; Ohe, Kaoru; Oshima, Tatsuya; Baba, Yoshinari; Kukizaki, Masato

    2009-03-15

    A novel wastewater treatment technique using 8 W low-pressure mercury lamps in the presence of uniform-sized microbubbles (diameter = 5.79 microm) was investigated for the decomposition of methyl orange as a model compound in aqueous solution. Photodegradation experiments were conducted with a BLB black light blue lamp (365 nm), a UV-C germicidal lamp (254 nm) and an ozone lamp (185 nm+254 nm) both with and without oxygen microbubbles. The results show that the oxygen microbubbles accelerated the decolorization rate of methyl orange under 185+254 nm irradiation. In contrast, the microbubbles under 365 and 254 nm irradiation were unaffected on the decolorization of methyl orange. It was found that the pseudo-zero order decolorization reaction constant in microbubble system is 2.1 times higher than that in conventional large bubble system. Total organic carbon (TOC) reduction rate of methyl orange was greatly enhanced by oxygen microbubble under 185+254 nm irradiation, however, TOC reduction rate by nitrogen microbubble was much slower than that with 185+254 nm irradiation only. Possible reaction mechanisms for the decolorization and mineralization of methyl orange both with oxygen and nitrogen mirobubbles were proposed in this study.

  8. DNA Damage and Repair in Plants under Ultraviolet and Ionizing Radiations

    PubMed Central

    Gill, Sarvajeet S.; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315–400 nm; UV-B, 280–315 nm; and UV-C, <280 nm) is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH•) and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context. PMID:25729769

  9. Role of phytochromes A and B in the regulation of cell death and acclimatory responses to UV stress in Arabidopsis thaliana

    PubMed Central

    Rusaczonek, Anna; Czarnocka, Weronika; Kacprzak, Sylwia; Witoń, Damian; Ślesak, Ireneusz; Szechyńska-Hebda, Magdalena; Gawroński, Piotr; Karpiński, Stanisław

    2015-01-01

    Plants coordinate their responses to various biotic and abiotic stresses in order to optimize their developmental and acclimatory programmes. The ultimate response to an excessive amount of stress is local induction of cell death mechanisms. The death of certain cells can help to maintain tissue homeostasis and enable nutrient remobilization, thus increasing the survival chances of the whole organism in unfavourable environmental conditions. UV radiation is one of the environmental factors that negatively affects the photosynthetic process and triggers cell death. The aim of this work was to evaluate a possible role of the red/far-red light photoreceptors phytochrome A (phyA) and phytochrome B (phyB) and their interrelations during acclimatory responses to UV stress. We showed that UV-C treatment caused a disturbance in photosystem II and a deregulation of photosynthetic pigment content and antioxidant enzymes activities, followed by increased cell mortality rate in phyB and phyAB null mutants. We also propose a regulatory role of phyA and phyB in CO2 assimilation, non-photochemical quenching, reactive oxygen species accumulation and salicylic acid content. Taken together, our results suggest a novel role of phytochromes as putative regulators of cell death and acclimatory responses to UV. PMID:26385378

  10. Photocatalytic removal of C.I. Basic Red 46 on immobilized TiO2 nanoparticles: artificial neural network modelling.

    PubMed

    Khataee, A R

    2009-10-01

    C.I. Basic Red 46, commonly used as a textile dye, was photocatalytically removed using supported TiO2 nanoparticles irradiated by a 30 W UV-C lamp in a batch reactor. The investigated photocatalyst was industrial Degussa P25 (crystallite mean size 21 nm) immobilized on glass beads by a heat attachment method. The catalyst was characterized by XRD, SEM, TEM and BET techniques. The process of the dye decolorization in the presence of TiO2 nanoparticles was experimentally studied through changing the initial dye concentration, UV light intensity and initial pH. The influence of inorganic anions such as chloride, sulphate, bicarbonate, carbonate and phosphate on the photocatalytic decolorization of BR46 was investigated. The decolorization of BR46 follows the pseudo-first-order kinetic according to the Langmuir-Hinshelwood model (k1 = 0.273 mg L(-1) min(-1), 2 = 0.313 (mg L(-1))(-1)). The efficiency parameters such as apparent quantum yield and electrical energy per order (EEO) were estimated. An artificial neural network model (ANN) was developed to predict the photocatalytic decolorization of BR46 solution. The findings indicated that the ANN provided reasonable predictive performance (R2 = 0.96). The influence of each parameter on the variable studied was assessed: initial concentration of the dye being the most significant factor, followed by the initial pH and reaction time.

  11. Decolorization of Reactive Blue 19 Dye from Textile Wastewater by the UV/H2O2 Process

    NASA Astrophysics Data System (ADS)

    Rezaee, Abbas; Taghi Ghaneian, Mohammad; Jamalodin Hashemian, Sayed; Moussavi, Gholamreza; Khavanin, Ali; Ghanizadeh, Ghader

    Photo-oxidation of dyes is a new concern among researchers since it offers an attractive method for decoloration of dyes and breaks them into simple mineral forms. An advanced oxidation process, UV/H2O2, was investigated in a laboratory scale photoreactor for decolorization of the Reactive blue 19 (RB19) dye from synthetic textile wastewater. The effects of operating parameters such as hydrogen peroxide dosage, pH, initial dye concentration and UV dosage, on decolorization have been evaluated. The RB19 solution was completely decolorized under optimal hydrogen peroxide dosage of 2.5 mmol L-1 and low-pressure mercury UV-C lamps (55 w) in less than 30 min. The decolorization rate followed pseudo-first order kinetics with respect to the dye concentration. The rate increased linearly with volumetric UV dosage and nonlinearly with increasing initial hydrogen peroxide concentration. It has been found that the degradation rate increased until an optimum of hydrogen peroxide dosage, beyond which the reagent exerted an inhibitory effect. From the experimental results, the UV/H2O2 process was an effective technology for RB19 dye treatment in wastewater.

  12. Photoprotective and toxicological activities of extracts from the Antarctic moss Sanionia uncinata

    PubMed Central

    Fernandes, Andréia da Silva; Alencar, Alexandre Santos; Evangelista, Heitor; Mazzei, José Luiz; Felzenszwalb, Israel

    2015-01-01

    Background: The Antarctic moss Sanionia uncinata (Hedw.) Loeske has shown high ultraviolet (UV)-absorbers content after exposition to high levels of UV-B radiation and can be an important source of antioxidants. Objective: The aim was to investigate photoprotection and mutagenicity by the aqueous extract (AE) and hydroethanolic extract (HE) from the Antarctic moss S. uncinata. Materials and Methods: Photoprotective activities were determined through survival curves of Escherichia coli strains, after UV irradiation in an aqueous solution of thymine and in vitro sun protection factor (SPF). The Salmonella/microsome assays were applied to assess the mutagenicity. Results: Both extracts induced photoprotection against UV-C radiation. The AE showed a higher protection than the hydroethanolic one against UV-induced thymine dimerization. The SPFs were low in both extracts. In association to benzophenone-3 a significant increase in the SPF was detected for the AE, and a significant decrease was induced by the HE. No mutagenicity was found in the both extracts. Furthermore, it was observed absence of cytotoxicity. Conclusion: Water-extractable compounds seem to contribute on photoprotection of this Antarctic moss. PMID:25709208

  13. Glimmers of Life in the Coronal Graveyard

    NASA Astrophysics Data System (ADS)

    Ayres, Thomas R.

    Red giants represent the final stage in the life cycle of normal stars. Those evolving from low-mass dwarfs like the Sun were magnetically active for most of their main sequence phase, thanks to a spin-catalyzed convective dynamo. At the same time, such stars also experienced significant rotational braking by their coronal winds. Once they expanded into red giants, their spins further plummeted, and they should have become magnetically dead; an expectation seemingly confirmed by a conspicuous lack of coronal X-ray detections. However, reports of the deaths of red giant coronae were premature - far-UV C IV emissions (an important coronal proxy) have been detected in archetype members of the class by HST, and now O VI has been seen by FUSE in at least one case. Curiously, however, features formed at similar temperatures -- Si IV and N V -- are absent, apparently removed by a mysterious cool absorber. Our objective is to obtain additional detections of the O VI doublet in key red giants, to help address the question of the nature of the cool absorber, and the implications for smothering any coronal X-ray emission. If we can show that there is lingering magnetic activity on the red giants, we might have found a possible link to the acceleration of their chromospheric winds, which chemically enrich the ISM and themselves are a long-standing astrophysical puzzle.

  14. Design and demonstration of ultra-wide bandgap AlGaN tunnel junctions

    DOE PAGES

    Zhang, Yuewei; Krishnamoorthy, Sriram; Akyol, Fatih; ...

    2016-09-19

    Ultra violet light emitting diodes (UV LEDs) face critical limitations in both the injection efficiency and the light extraction efficiency due to the resistive and absorbing p-type contact layers. In this work, we investigate the design and application of polarization engineered tunnel junctions for ultra-wide bandgap AlGaN (Al mole fraction >50%) materials towards highly efficient UV LEDs. We demonstrate that polarization-induced three dimensional charge is beneficial in reducing tunneling barriers especially for high composition AlGaN tunnel junctions. In addition, the design of graded tunnel junction structures could lead to low tunneling resistance below 10–3 Ω cm2 and low voltage consumptionmore » below 1 V (at 1 kA/cm2) for high composition AlGaN tunnel junctions. Experimental demonstration of 292 nm emission was achieved through non-equilibrium hole injection into wide bandgap materials with bandgap energy larger than 4.7 eV, and detailed modeling of tunnel junctions shows that they can be engineered to have low resistance and can enable efficient emitters in the UV-C wavelength range.« less

  15. Immobilization of TiO2 nanopowder on glass beads for the photocatalytic decolorization of an azo dye C.I. Direct Red 23.

    PubMed

    Daneshvar, N; Salari, D; Niaei, A; Rasoulifard, M H; Khataee, A R

    2005-01-01

    TiO2 supported on glass beads was prepared and its photocatalytic activity was determined by photooxidation of the commercial textile dye, C.I. Direct Red 23, in aqueous solution illuminated by a UV-C lamp (30 W). The progress of photocatalytic decolorization of the C.I. Direct Red 23 was studied by measuring the absorbance at lambda(max) = 507 nm by UV Vis spectrophotometer. The experiments indicated that both UV light and TiO2 were needed for the effective destruction of the dye. The effect of pH on the rate of decolorization efficiency was followed in the pH range 2-12. Acidic pH range was found to favor the decolorization rate. The addition of a proper amount of hydrogen peroxide improved the decolorization, whereas the excess hydrogen peroxide quenched the formation of hydroxyl radicals (*OH). The electrical energy consumption per order of magnitude for photocatalytic decolorization of the dye was lower in the UV/TiO2/H2O2 process than that in the UV/TiO2 process. In the real wastewater sample the efficiency of the method was determined by measuring the changes in the absorption spectra of the dye solution during photodegradation. Our results indicated that during the photooxidation process, the decolorization efficiency was more than 80% at irradiation time of 3 h.

  16. Exobiological investigations on Russian spacecrafts.

    PubMed

    Kuzicheva, Evgenia A; Gontareva, Natalia B

    2003-01-01

    To investigate the possibility of prebiotic synthesis of organic molecules in open space, conditions involved irradiating nucleosides and inorganic phosphate during five Earth-orbiting Russian space missions that included Salut-7 (13- and 16-month missions), Mir, Bion-11, and Cosmos-2044. Dry films of samples were exposed from 2 weeks up to 16 months to the entire set of factors encountered in open space during Earth-orbiting missions. After each mission, products synthesized during flight and any compounds that remained undegraded were analyzed. The analyses demonstrated that increased flight duration led to the decay of both synthesized nucleotides and initial nucleosides. Corresponding laboratory experiments indicated that infrared radiation caused the greatest amount of decay to products of prebiotic reactions. Experiments revealed that 5'-mononucleotides were the main chemical products of the major derivatives synthesized of certain nucleosides. Exposure to ultraviolet (UV) C(145) was more effective than UVC(254) in producing a comparatively higher yield of mononucleotides, while the energy flux of the latter was one order of magnitude less (10(-7) as compared with 10(-6) for UVC(145)). In the course of the laboratory simulation experiments the heating of solid samples yielded the greatest production amount (6.34% for adenosine derivatives).

  17. Exobiological Investigations on Russian Spacecrafts

    NASA Astrophysics Data System (ADS)

    Kuzicheva, Evgenia A.; Gontareva, Natalia B.

    2003-06-01

    To investigate the possibility of prebiotic synthesis of organic molecules in open space, conditions involved irradiating nucleosides and inorganic phosphate during five Earth-orbiting Russian space missions that included Salut-7 (13- and 16-month missions), Mir, Bion-11, and Cosmos-2044. Dry films of samples were exposed from 2 weeks up to 16 months to the entire set of factors encountered in open space during Earth-orbiting missions. After each mission, products synthesized during flight and any compounds that remained undegraded were analyzed. The analyses demonstrated that increased flight duration led to the decay of both synthesized nucleotides and initial nucleosides. Corresponding laboratory experiments indicated that infrared radiation caused the greatest amount of decay to products of prebiotic reactions. Experiments revealed that 5'-mononucleotides were the main chemical products of the major derivatives synthesized of certain nucleosides. Exposure to ultraviolet (UV) C145 was more effective than UVC254 in producing a comparatively higher yield of mononucleotides, while the energy flux of the latter was one order of magnitude less (10-7 as compared with 10-6 for UVC145). In the course of the laboratory simulation experiments the heating of solid samples yielded the greatest production amount (6.34% for adenosine derivatives).

  18. Microflora associated with spacecraft and assembly facility surfaces

    NASA Astrophysics Data System (ADS)

    La Duc, M. T.; Osman, S.; Dekas, A. E.; Moissl, C.; Newcombe, D.; Venkateswaran, K.

    The direct analysis of microbial populations contained within low biomass samples is germane to a multitude of NASA programs Although stringent maintenance helps to keep the bioburden associated with spacecraft and assembly facility surfaces nominal the microorganisms that do persist however sparse they may be threaten forward contamination on future missions While examining the cultivable microbial diversity associated with spacecraft and assembly facility surfaces over the past 6 years 1999-2005 the recurring predominance of Bacillus pumilus has been observed Since its endospores are often capable of withstanding exposure to peroxides UV and gamma radiation and long bouts of desiccation the repeated isolation of B pumilus from the surfaces of spacecraft may bear great consequence to planetary protection Microflora seemingly tailored to enduring environmentally harsh extreme conditions have also been isolated from these surfaces Upon subjecting samples collected from clean room surfaces to UV-C irradiation 5 hydrogen peroxide heat shock 85 C 15 minutes acidic pH 3 0 alkaline pH 11 0 and saline 25 NaCl conditions and incubated at varying temperatures 4 C to 65 C members of the Bacillus genera accounted for a mere 40 of the isolated population Furthermore isolates belonging to the Bacillaceae family were more physiologically diverse than those isolated in previous studies including thermophiles

  19. Photoprotective Bioactivity Present in a Unique Marine Bacteria Collection from Portuguese Deep Sea Hydrothermal Vents

    PubMed Central

    Martins, Ana; Tenreiro, Tania; Andrade, Gonçalo; Gadanho, Mário; Chaves, Sandra; Abrantes, Marta; Calado, Patrícia; Tenreiro, Rogério; Vieira, Helena

    2013-01-01

    Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea hydrothermal vents near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR vents collection in natural product synthesis with market applications. PMID:23665957

  20. Application of nano-TiO2/LDPE composite film on photocatalytic oxidation degradation of dichloromethane.

    PubMed

    Suwannahong, Kowit; Liengcharernsit, Winai; Sanongraj, Wipada; Kruenate, Jittiporn

    2012-09-01

    This study focused on the photocatalytic destruction of dichloromethane (DCM) in indoor air using the nano-TiO2/LDPE composite film as an economical photocatalyst. The nano-TiO2 was dispersed in a polyethylene matrix to form composite film. The photocatalytic activity of the nano-TiO2/LDPE composite films was evaluated through the degradation of dichloromethane(DCM) under UV-C irradiance at specific wavelength of 254 nm. The percentage of nano-TiO2 contents varied from 0, 5, and 10% (wt cat./wt LDPE composite film). The results derived from the kinetic model revealed that the photocatalytic rates of 5 and 10 wt.% nano-TiO2/ LDPE composite films follow the first order reaction while the rate of the film without TiO2 followed the zero order reaction. At low concentration of DCM, the rate of photocatalytic degradation of the DCM was slower than that at high DCM concentration. The 10 wt.% of TiO2 content of the nano-TiO2/LDPE composite film yielded the highest degradation efficiency of 78%, followed by the removal efficiency of 55% for the 5 wt.% of TiO2 content of the nano-TiO2/LDPE composite film. In contrast with the composite film containing nano-TiO2, the LDPE film without adding nano-TiO2 expressed the degradation efficiency of 28%.

  1. UV-Heat Treatments for the Control of Foodborne Microbial Pathogens in Chicken Broth

    PubMed Central

    Gouma, M.; Gayán, E.; Raso, J.; Condón, S.; Álvarez, I.

    2015-01-01

    This investigation established the process criteria for using UV-C light and mild heat (UV-H treatment) to inactivate 5-Log10 cycles (performance criterion) of common foodborne pathogen populations, Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, when inoculated in chicken broth. To define the target microorganism and the proper UV-H treatment conditions (including UV dose, treatment time, and temperature) that would achieve the stated performance criterion, mathematical equations based on Geeraerd's model were developed for each microorganism. For the sake of comparison, inactivation equations for heat treatments were also performed on the same chicken broth and for the same microorganisms. L. monocytogenes was the most UV-H resistant microorganism at all temperatures, requiring a UV dose between 6.10 J/mL (5.6 min) and 2.26 J/mL (2.09 min) to achieve 5-Log10 reductions. In comparison with UV treatments at room temperatures, the combination of UV and mild heat allowed both the UV dose and treatment time to be reduced by 30% and 63% at 55°C and 60°C, respectively. Compared to heat treatments, the UV-H process reduced the heating time for 5-Log10 reductions of all the investigated microorganisms in chicken broth from 20-fold to 2-fold when the operating temperature varied from 53 to 60°C. PMID:26539493

  2. Stability-indicating LC assay for butenafine hydrochloride in creams using an experimental design for robustness evaluation and photodegradation kinetics study.

    PubMed

    Barth, Aline Bergesch; de Oliveira, Gabriela Bolfe; Malesuik, Marcelo Donadel; Paim, Clésio Soldatelli; Volpato, Nadia Maria

    2011-08-01

    A stability-indicating liquid chromatography method for the determination of the antifungal agent butenafine hydrochloride (BTF) in a cream was developed and validated using the Plackett-Burman experimental design for robustness evaluation. Also, the drug photodegradation kinetics was determined. The analytical column was operated with acetonitrile, methanol and a solution of triethylamine 0.3% adjusted to pH 4.0 (6:3:1) at a flow rate of 1 mL/min and detection at 283 nm. BTF extraction from the cream was done with n-butyl alcohol and methanol in ultrasonic bath. The performed degradation conditions were: acid and basic media with HCl 1M and NaOH 1M, respectively, oxidation with H(2)O(2) 10%, and the exposure to UV-C light. No interference in the BTF elution was verified. Linearity was assessed (r(2) = 0.9999) and ANOVA showed non-significative linearity deviation (p > 0.05). Adequate results were obtained for repeatability, intra-day precision, and accuracy. Critical factors were selected to examine the method robustness with the two-level Plackett-Burman experimental design and no significant factors were detected (p > 0.05). The BTF photodegradation kinetics was determined for the standard and for the cream, both in methanolic solution, under UV light at 254 nm. The degradation process can be described by first-order kinetics in both cases.

  3. Rapid Approaches Towards DNA Damage Analysis

    PubMed Central

    Crews, N.; Paidipalli, Manasa

    2013-01-01

    The severe effects of DNA damage on human health have led to a tremendous amount of research being focused. Owing to the importance of damage detection, different approaches for the detection and quantification of the damaged DNA will be presented. In this work, we have modeled DNA damage using well-known mutagens: UV radiation to create photoproducts and restriction enzyme digestion to create double strand breaks. We will show that quantitative PCR (qPCR), a widely known measure of detecting the presence of the target DNA can be used to quantify photoproducts/intramolecular DNA damage. Our results indicate that a comparison of the initial concentration available in the undamaged and the damaged samples can be used to reveal the effect of damaged DNA in its amplification. By analyzing multiple regions using this technique, their relative susceptibility to damage can be measured. We also show that high-resolution melting analysis (HRMA), a measure of the bond energy between two DNA strands, can be used to quantify double strand breaks. The strand breaks resulted in a change in the overall distribution of the bond energy thus causing variations in the melting profile. HRMA has also been examined to compare DNA damage resulting from UV-A, UV-B and UV-C irradiation. The evaluation techniques demonstrated can potentially be extended to various types of DNA damage.

  4. Single-step intercalating dye strategies for DNA damage studies.

    PubMed

    Paidipalli, Manasa; Pjescic, Ilija; Hindmarsh, Patrick L; Crews, Niel D

    2013-08-01

    Many analytical protocols exist for the quantification of varied types of DNA damage, which span a range of complexity and sensitivity. As an alternative or companion to existing procedures, this article demonstrates the application of quantitative PCR (qPCR) and high-resolution DNA melting analysis (HRMA) to the detection and quantification of intramolecular DNA damage and/or strand breaks. These proven molecular biology methods are essentially single-step processes. When implemented with a third-generation saturating DNA dye, high sensitivity can be obtained. The experiments presented here demonstrate how DNA damage can inhibit amplification of the affected molecules. This corresponding decrease in the initial concentration of amplifiable DNA can be measured with qPCR. In addition, damage in the form of intramolecular dimerization and strand breaks alters the stored energy in the hydrogen bonds between the two strands in the dsDNA molecule. This significantly affects the thermal stability, which can be measured with extreme precision using HRMA. Simplified damage models were used in these experiments: UV-C irradiation to produce photoproducts, and restriction enzyme digestion to simulate double-strand breaks. The findings of this work, however, can be intuitively applied to the broad scope of DNA damage mechanisms.

  5. An AlGaN Core-Shell Tunnel Junction Nanowire Light-Emitting Diode Operating in the Ultraviolet-C Band.

    PubMed

    Sadaf, S M; Zhao, S; Wu, Y; Ra, Y-H; Liu, X; Vanka, S; Mi, Z

    2017-02-08

    To date, semiconductor light emitting diodes (LEDs) operating in the deep ultraviolet (UV) spectral range exhibit very low efficiency due to the presence of large densities of defects and extremely inefficient p-type conduction of conventional AlGaN quantum well heterostructures. We have demonstrated that such critical issues can be potentially addressed by using nearly defect-free AlGaN tunnel junction core-shell nanowire heterostructures. The core-shell nanowire arrays exhibit high photoluminescence efficiency (∼80%) in the UV-C band at room temperature. With the incorporation of an epitaxial Al tunnel junction, the p-(Al)GaN contact-free nanowire deep UV LEDs showed nearly one order of magnitude reduction in the device resistance, compared to the conventional nanowire p-i-n device. The unpackaged Al tunnel junction deep UV LEDs exhibit an output power >8 mW and a peak external quantum efficiency ∼0.4%, which are nearly one to two orders of magnitude higher than previously reported AlGaN nanowire devices. Detailed studies further suggest that the maximum achievable efficiency is limited by electron overflow and poor light extraction efficiency due to the TM polarized emission.

  6. The Application of Coreless Inductors for Displacement Measurements in Laboratory Investigations of Rock Properties

    NASA Astrophysics Data System (ADS)

    Nurkowski, Janusz

    2014-12-01

    The paper presented the coreless inductive sensor, its construction and principle of operation. The impact of temperature on the outcome of a measurement performed with the inductor was discusses, together with the possibility of temperature compensation of the inductor's performance. Subsequently, the reasons for limited measurement accuracy and resolution were discussed, particularly under the variable pressure in the order of some hundreds MPa. Two types of such sensor were presented: a sensor for measuring linear strains, e.g. during compressibility measurements, and an sensor for measuring circumferential strains during triaxial compression tests. Additionally, the manners of fixing the sensor on rock samples were presented. Finally, some examples of the sensor application were shown, together with the results of measurements of deformations of rock samples - especially in cases when resistance gauges cannot be used, and the samples are subjected to a load in the uniaxial and triaxial system, under the hydrostatic pressure of up to 400 MPa and the normal one. W Pracowni Odkształceń Skał Instytutu Mechaniki Górotworu prowadzone są badania właściwości mechanicznych skał. Wymaga to precyzyjnego pomiaru odkształcenia, na ogół pod wysokim ciśnieniem hydrostatycznym, które symuluje warunki panujące w głębi górotworu. Ciśnienie hydrostatyczne (do 400MPa w aparacie GTA-10) i ograniczona do kilku milimetrów przestrzeń w komorze ciśnieniowej na zainstalowanie odpowiedniego przyrządu, a także spękania i kawerny w skałach powodują znaczne trudności pomiaru odkształcenia z wymaganą rozdzielczością (nawet 10-6). Stosowanie tensometrów elektrooporowych naklejanych wprost na próbkę często jest zawodne, gdyż ciśnienie wgniata ścieżkę rezystancyjną w nierówności próbki, powodując jej przerwanie, a co gorsze, fałszuje wyniki pomiaru. Wypełnianie szczelin lub kawern różnymi podkładami jak klej epoksydowy, gips, jest

  7. Feasibility Analysis of Groundwater Abstraction for Gas Shale Fracturing in the Lublin Basin (Eastern Poland) / Ocena Możliwości Poboru Wód Podziemnych Do Szczelinowania Łupków Gazonośnych W Basenie Lubelskim (Wschodnia Polska)

    NASA Astrophysics Data System (ADS)

    Duda, Robert; Macuda, Jan

    2015-03-01

    szczelinowania skał. Zabiegi te realizowane są przy wykorzystaniu dużych ilości cieczy szczelinujących, które w 90.5% składają się z wody, 9.0% piasku podsadzkowego (proppant) oraz 0.5% różnych substancji chemicznych, niezbędnych do utrzymania właściwych parametrów technologicznych cieczy. Zapotrzebowanie na wodę do szczelinowania wzrasta wraz ze zwiększeniem zwięzłości i głębokości zalegania łupków gazonośnych. W związku z tym właściciele koncesji na eksploatację gazu ze skał łupkowych oczekują informacji o możliwościach poboru wód podziemnych w celu szczelinowania. W pracy przedstawiono ocenę realnych możliwości poboru wód podziemnych do przygotowania cieczy szczelinujących dla otworów eksploatacyjnych gazu niekonwencjonalnego w obszarze basenu lubelskiego, będącego rejonem perspektywicznej eksploatacji gazu z łupków ordowiku i syluru (dolny paleozoik). Możliwości poboru wody zbadano na podstawie oczekiwanych wydajności jednostkowych studni ujmujących wody głównego użytkowego poziomu wodonośnego (GUPW) w rejonie badań. GUPW na przeważającej części tego obszaru związany jest ze skałami górnej kredy - spękanymi marglami, kredą, opokami, wapieniami i gezami, a także utworami czwartorzędu i trzeciorzędu. Znajomość wartości wydatku jednostkowego umożliwia zaprojektowanie ujęcia stosownie do określonych potrzeb. Witczak et al. (1999) proponują przyjęcie wydatku jednostkowego studni (q), jako obiektywnej danej empirycznej cechującej się wysokim wskaźnikiem pewności, w celu charakterystyki wodonośności poziomów wodonośnych w skali regionalnej. Przestrzenną ocenę wartości q oparto na danych zestawionych w 7 arkuszach Mapy hydrogeologicznej Polski w skali 1:200,000 (MHP). Dane dotyczyły q uzyskiwanych przy określonych maksymalnych depresjach poziomu wody. Obliczono q studni ujmujących wodę z GUPW w formacjach kredy górnej, trzeciorzędu i czwartorzędu, w granicach obszarów arkuszy MHP lub ich cz

  8. Free Surface of the Liquid-Gas Phase Separation as a Measuring Membrane of a Device for Measuring Small Hydrostatic Pressure Difference Values / Powierzchnia Swobodna Rozdziału Faz Ciecz-Gaz Jako Membrana Pomiarowa Urządzenia Do Pomiaru Małych Wartości Różnicy Ciśnienia Hydrostatycznego

    NASA Astrophysics Data System (ADS)

    Filipek, Wiktor; Broda, Krzysztof; Branny, Marian

    2015-03-01

    środek (Bear, 1988) lub rozkładu ciśnienia przy wysokich spadkach hydraulicznych (Trzaska i Broda, 1991, 2000; Trzaska i in., 2005). Zwłaszcza pomiary w zakresie tzw. dolnej granicy stosowalności prawa Darcy'ego dla cieczy oraz dotyczące określenia progowego spadku hydraulicznego J0 (Bear, 1988) sprawiają wielkie trudności. Pomiary takie miałyby duże znaczenie aplikacyjne zwłaszcza przy określaniu infiltracji wody do wyrobisk górniczych, filtracji przez fundamenty budowli itp. Autorzy od kilku lat (Broda i Filipek, 2012, 2013) zajmują się opracowaniem metody oraz przyrządu pomiarowego (wnioski patentowe: P.407 380 i P.407 381) pozwalających na pomiary wartości ciśnienia (różnicy ciśnienia) hydrostatycznego poniżej 1 Pa. W tym okresie opracowali nową metodę pomiaru, skonstruowali stanowisko badawcze i przeprowadzili pomiary różnicy ciśnień hydrostatycznych z dokładnością do 0.5 Pa znacznie ograniczając zjawisko histerezy (Broda i Filipek, 2012) (wniosek patentowy: P.407 380). W oparciu o zdobyte doświadczenie prace kontynuowano opracowując metodę pomiaru i budując nowe stanowisko do pomiaru bardzo małych różnic ciśnień z kompensacją wpływu ciśnienia atmosferycznego o dużo prostszej budowie, co znacząco zwiększyło dokładność i wiarygodność pomiarów (Broda i Filipek, 2013) (wniosek patentowy: P. 407 381). W trakcie prac badawczych narodziła się nowa koncepcja metodologii pomiaru niskich wartości różnicy ciśnienia hydrostatycznego, która jest przedmiotem niniejszego artykułu. Na rysunku 1 przedstawiono zdjęcie stanowiska pomiarowego służącego do określenia wpływu zmiany wartości różnicy ciśnienia hydrostatycznego na kształt a co za tym idzie przemieszczenie powierzchni swobodnej rozdziału faz ciecz-gaz, oraz omówiono jego budowę zwracając uwagę na istotne szczegóły konstrukcyjne. Przedstawiono także sposób kalibrowania przyrządu, wykonywania i obróbki zdjęć fotograficznych w celach pomiarowych z

  9. UV protective poly(lactic acid)/rosin films for sustainable packaging.

    PubMed

    Narayanan, Meenu; Loganathan, Sravanthi; Valapa, Ravi Babu; Thomas, Sabu; Varghese, T O

    2017-06-01

    Recently, biopolymer based plastic materials are regarded as potential alternative for conventional plastics of fossil fuel origin in order to compensate depleting petroleum resources and address environmental pollution issues. Poly(lactic acid) (PLA) is one among the biopolymers which is rapidly commercialized for food packaging application. However, the demerits accompanied with PLA like brittle nature, slower crystallization rate, poor gas barrier and high ultraviolet radiation transmission properties confines its commercial application in food packaging sector. Studies on the improvement of ductility, crystallization rate and gas barrier properties are markedly reported. Much emphasis is not given in the literature on improving UV shielding properties which plays important role in preventing oxidation degradation of PLA. Therefore, the current work is focused on fabrication of eco-friendly poly(lactic acid)/rosin (RS) based biocomposite films with improved UV shielding along with ductility and oxygen barrier properties. The PLA-RS biocomposite films containing different loadings (1, 3, 5, 10 and 20wt%) of RS with an average thickness of 50μm are fabricated via solution casting technique. The PLA-RS film demonstrated noteworthy light barrier feature by shielding the passage of ∼98%, 92% and 53% in UV-B, UV-A and visible light regime, respectively. In case of UV-C region, complete blockage of UV transmission through the PLA-RS biocomposite film is noticed. In addition to this, the presence of RS in the PLA matrix brought considerable improvement in terms of ductility and oxygen barrier characteristics. This in turn indicates PLA-RS biocomposite films hold significant potential for sustainable food packaging application.

  10. Reference gene validation for quantitative RT-PCR during biotic and abiotic stresses in Vitis vinifera.

    PubMed

    Borges, Alexandre Filipe; Fonseca, Catarina; Ferreira, Ricardo Boavida; Lourenço, Ana Maria; Monteiro, Sara

    2014-01-01

    Grapevine is one of the most cultivated fruit crop worldwide with Vitis vinifera being the species with the highest economical importance. Being highly susceptible to fungal pathogens and increasingly affected by environmental factors, it has become an important agricultural research area, where gene expression analysis plays a fundamental role. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is currently amongst the most powerful techniques to perform gene expression studies. Nevertheless, accurate gene expression quantification strongly relies on appropriate reference gene selection for sample normalization. Concerning V. vinifera, limited information still exists as for which genes are the most suitable to be used as reference under particular experimental conditions. In this work, seven candidate genes were investigated for their stability in grapevine samples referring to four distinct stresses (Erysiphe necator, wounding and UV-C irradiation in leaves and Phaeomoniella chlamydospora colonization in wood). The expression stability was evaluated using geNorm, NormFinder and BestKeeper. In all cases, full agreement was not observed for the three methods. To provide comprehensive rankings integrating the three different programs, for each treatment, a consensus ranking was created using a non-weighted unsupervised rank aggregation method. According to the last, the three most suitable reference genes to be used in grapevine leaves, regardless of the stress, are UBC, VAG and PEP. For the P. chlamydospora treatment, EF1, CYP and UBC were the best scoring genes. Acquaintance of the most suitable reference genes to be used in grapevine samples can contribute for accurate gene expression quantification in forthcoming studies.

  11. Sporulation Temperature Reveals a Requirement for CotE in the Assembly of both the Coat and Exosporium Layers of Bacillus cereus Spores

    PubMed Central

    Bressuire-Isoard, Christelle; Bornard, Isabelle; Henriques, Adriano O.; Carlin, Frédéric

    2015-01-01

    The Bacillus cereus spore surface layers consist of a coat surrounded by an exosporium. We investigated the interplay between the sporulation temperature and the CotE morphogenetic protein in the assembly of the surface layers of B. cereus ATCC 14579 spores and on the resulting spore properties. The cotE deletion affects the coat and exosporium composition of the spores formed both at the suboptimal temperature of 20°C and at the optimal growth temperature of 37°C. Transmission electron microscopy revealed that ΔcotE spores had a fragmented and detached exosporium when formed at 37°C. However, when produced at 20°C, ΔcotE spores showed defects in both coat and exosporium attachment and were susceptible to lysozyme and mutanolysin. Thus, CotE has a role in the assembly of both the coat and exosporium, which is more important during sporulation at 20°C. CotE was more represented in extracts from spores formed at 20°C than at 37°C, suggesting that increased synthesis of the protein is required to maintain proper assembly of spore surface layers at the former temperature. ΔcotE spores formed at either sporulation temperature were impaired in inosine-triggered germination and resistance to UV-C and H2O2 and were less hydrophobic than wild-type (WT) spores but had a higher resistance to wet heat. While underscoring the role of CotE in the assembly of B. cereus spore surface layers, our study also suggests a contribution of the protein to functional properties of additional spore structures. Moreover, it also suggests a complex relationship between the function of a spore morphogenetic protein and environmental factors such as the temperature during spore formation. PMID:26497467

  12. Degradation of acid blue 40 dye solution and dye house wastewater from textile industry by photo-assisted electrochemical process.

    PubMed

    Moraes, Peterson B; Pelegrino, Rosangela R L; Bertazzoli, Rodnei

    2007-12-01

    In this paper, electrochemical and photo-assisted electrochemical processes are used for color, total organic carbon (TOC) and chemical oxygen demand (COD) degradation of one of the most abundant and strongly colored industrial wastewaters, which results from the dyeing of fibers and fabrics in the textile industry. The experiments were carried out in an 18 L pilot-scale tubular flow reactor with 70%TiO(2)/30%RuO(2) DSA. A synthetic acid blue 40 solution and real dye house wastewater, containing the same dye, were used for the experiments. By using current density of 80 mA cm(-2) electrochemical process has the capability to remove 80% of color, 46% of TOC and 69% of COD. When used the photochemical process with 4.6 mW cm(-2) of 254 nm UV-C radiation to assist the electrolysis, has been obtained 90% of color, 64% of TOC and 60% of COD removal in 90 minutes of processing; furthermore, 70% of initial color was degraded within the first 15 minutes. Experimental runs using dye house wastewater resulted in 78% of color, 26% of TOC and 49% of COD in electrolysis at 80 mA cm(-2) and 90 min; additionally, when photo-assisted, electrolysis resulted in removals of 85% of color, 42% of TOC and 58% of COD. For the operational conditions used in this study, color, TOC and COD showed pseudo-first-order decaying profiles. Apparent rate constants for degradation of TOC and COD were improved by one order of magnitude when the photo-electrochemical process was used.

  13. On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source

    NASA Astrophysics Data System (ADS)

    Kislyakova, K. G.; Pilat-Lohinger, E.; Funk, B.; Lammer, H.; Fossati, L.; Eggl, S.; Schwarz, R.; Boudjada, M. Y.; Erkaev, N. V.

    2016-09-01

    We suggest an additional possible plasma source to explain part of the phenomena observed for the transiting hot Jupiters WASP-12b and HD 189733b in their ultraviolet (UV) light curves. In the proposed scenario, material outgasses from the molten surface of Trojan satellites on tadpole orbits near the Lagrange points L4 and L5. We show that the temperature at the orbital location of WASP-12b is high enough to melt the surface of rocky bodies and to form shallow lava oceans on them. In case of WASP-12b, this leads to the release of elements such as Mg and Ca, which are expected to surround the system. The predicted Mg and Ca outgassing rates from two Io-sized WASP-12b Trojans are ≈2.2 × 1027 s-1 and ≈2.2 × 1026 s-1, respectively. Trojan outgassing can lead to the apparent lack of emission in Mg II h&k and Ca II H&K line cores of WASP-12. For HD 189733b, the mechanism is only marginally possible due to the lower temperature. This may be one of the reasons that could not explain the early ingress of HD 189733b observed in the far-UV C II doublet due to absence of carbon within elements outgassed by molten lava. We investigate the long-term stability region of WASP-12b and HD 189733b in case of planar and inclined motion of these satellites and show that unlike the classical exomoons orbiting the planet, Io-sized Trojans can be stable for the whole systems lifetime.

  14. Adsorption of human fibrinogen and albumin onto hydrophobic and hydrophilic Ti6Al4V powder

    NASA Astrophysics Data System (ADS)

    Rodríguez-Sánchez, Jesús; Gallardo-Moreno, Amparo M.; Bruque, José M.; González-Martín, M. Luisa

    2016-07-01

    Adsorption of proteins on solid surfaces has been widely studied because of its importance in various biotechnological, medical and technical applications, such as medical implants or biosensors. One of the main problems is the adsorption-induced conformational changes because they often modify the biological activity of the proteins, which is believed to be a key factor on the subsequent cellular adhesion. The aim of this work is the study of the adsorption of human fibrinogen (Fg) and human serum albumin (HSA) onto Ti6Al4V particles, commercially available on different size, that are used to elaborate scaffolds to provide structural support to cell proliferation, promoting tissue development and bone regeneration among others. The study was done through the analysis of the adsorption isotherms and the electrical characterization of surfaces after adsorption in terms of the zeta potential (ζ). From this analysis it seems that Fg adsorbs preferentially vertically oriented (end-on) and HSA moves sequentially over the surface of the Ti6Al4V particles through dimmer formation, allowing adsorption progress over this initial bilayer. The zeta potential values of both proteins remain constant when the monolayer is formed. The study also extends the analysis of both adsorption behaviour and ζ potential characterization factors to the influence of the substrate hydrophobicity as this property can be modified for the Ti6Al4V by irradiating it with ultraviolet light (UV-C) without changes on its chemical composition [1,2]. Differences at low protein concentrations were found for both isotherms and zeta-potential values.

  15. A potential new biosignature of life in iron-rich extreme environments: An iron (III) complex of scytonemin and proposal for its identification using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Varnali, Tereza; Edwards, Howell G. M.

    2013-07-01

    Scytonemin is a cyanobacterial sheath pigment with potent UV absorbing (UV-A, UV-B and UV-C) properties. The importance of this biomolecule is its photoprotective function which is one of the major survival strategies adopted by extremophiles to combat high energy radiation insolation in environmentally stressed conditions. Also, iron (III) oxides offering an additional UV-protecting facility to subsurface biological colonization as well as banded iron formations with zones of iron depletion in rock matrices have attracted attention with special interest in the mobilisation and transportation of iron compounds through the rock. This study represents a novel proposal that an iron-scytonemin complex could facilitate the movement of iron through the subsurface rock as part of the this extremophilic survival strategy. The predicted Raman wavenumbers for the proposed scytonemin complex of iron(III) are derived computationally using DFT calculations. Comparison of the experimentally observed Raman spectra of scytonemin with the theoretically predicted Raman spectra of the iron-scytonemin complex show that the latter may be discriminated and the expected characteristic bands are reported in relation to structural changes that are effected upon complexation. This information will inform the future search for experimental evidence for an iron-scytonemin complex, which has not been recognised hitherto and which could provide a novel biosignature for the extremophilic colonization of terrestrial iron-rich geological matrices. Such a terrestrial scenario would be potentially of significance for the remote robotic analytical exploration of the iron-rich surface and immediate subsurface of Mars.

  16. Bacillus Endospores - an ideal exobiological Tool

    NASA Astrophysics Data System (ADS)

    Moeller, R.; Horneck, G.

    Exobiology investigations have one overall goal -- finding the answer to the question if Earth is the only possible place in our universe where life was created. For tackling this question a good approach is to use a simple and ubiquitous system like bacteria as used in BIOPAN and EXPOSE. Many of these microorganisms have the ability to form metabolic inactive continuous forms such as Bacillus endospores. These spores are highly resistant against a variety of environmental stresses, such as toxic chemical agents, desiccation, high and low pressure, high doses of ionising and UV radiation and temperature extremes such as heat or permafrost. They are ubiquitous, inhabit soils and rocks and are easily disseminated by wind and water. Therefore they are suitable test systems for studying several questions of astrobiology, such as the theory of Panspermia, planetary protection issues in connection with missions to Mars or Europa, or chances for life on past or present Mars. The strategies Bacillus sp. endospores have developed to survive harsh conditions include a desiccated spore core, an altered conformation of their DNA (A-form), high concentration of small acid-soluble proteins (SASPs) stabilising the DNA, dipicolinic acid (DPA) for stabilisation and protective spore coating layers. We have investigated the role of endogenous and exogenous pigments in the UV-resistance of Bacillus endospores by using spores of different degree and kind of pigmentation, i.e. white, grey or red spores (DSMZ culture collection). The spectral ranges of UV radiation represented those of the early or present UV radiation climate of Earth or Mars. It was found, that endogenous carotenoids, identified by spectrophotometrical analysis from a spore extract as well as in-situ by Raman spectroscopy, efficiently protect against UV-A radiation, whereas melanin was also protective against UV-C radiation. From these studied follows, that highly pigmented spores might survive even in an intense UV

  17. Effect of Processing, Post-Harvest Irradiation, and Production System on the Cytotoxicity and Mutagenicity of Vitis labrusca L. Juices in HTC Cells

    PubMed Central

    Düsman, Elisângela; de Almeida, Igor Vivian; Lucchetta, Luciano; Vicentini, Veronica Elisa Pimenta

    2014-01-01

    The juices of grapes (Vitis labrusca L.) are similar to the fruit itself because the main constituents of the fruit are present in the juice. However, their quality characteristics may be modified by the harsh technological processes used for the production of integral food, such as production systems of raw materials and post-harvest treatment of grapes with ultraviolet (UV) irradiation. Therefore, the present study analyzed juices produced naturally (by liquefying the fruit) or by the technological process of extraction by steam distillation (90°C) of grapes from organic and conventional production systems that were untreated or treated with UV type C (65.6 J/m2 for 10 minutes). Using cultures of Rattus norvegicus hepatoma cells (HTC) in vitro, cytotoxic effects were assayed by the MTT test and by calculating the cytokinesis blocked proliferation index (CBPI), and mutagenic effects were measured by the cytokinesis block micronucleus assay. The results of the MTT assay and the CBPIs indicated that none of the juices were cytotoxic, including those that induced cell proliferation. The results of the micronucleus assay showed that none of the juices were mutagenic. However, the average number of micronuclei was lower in the juices produced from organic grapes, and cell proliferation, soluble acids and phenolic compounds were significantly higher. Compared with the natural juices, the integral juices of conventional grapes showed a higher average number of micronuclei as well as lower stimulation of cell proliferation and lower levels of bioactive compounds. The results demonstrate a beneficial effect of UV-C irradiation of post-harvest grapes in stimulating the synthesis of nutraceutical compounds without generating cytotoxic or mutagenic substances. Taken together, our findings support the consumption of grape juice and the application of food production techniques that enhance its nutritional value and promote its production, marketing and consumption. PMID

  18. Effects of titanium dioxide nanoparticles on human keratinocytes.

    PubMed

    Wright, Clayton; Iyer, Anand Krishnan V; Wang, Liying; Wu, Nianqiang; Yakisich, Juan S; Rojanasakul, Yon; Azad, Neelam

    2017-01-01

    Titanium dioxide (TiO2) is a ubiquitous whitening compound widely used in topical products such as sunscreens, lotions and facial creams. The damaging health effects of TiO2 inhalation has been widely studied in rats, mice and humans showing oxidative stress increase, DNA damage, cell death and inflammatory gene upregulation in lung and throat cells; however, the effects on skin cells from long-term topical use of various products remain largely unknown. In this study, we assessed the effect of specific TiO2 nanoparticles (H2TiO7) on a human keratinocyte cell line (HaCaT). We performed a comparative analysis using three TiO2 particles varying in size (Fine, Ultrafine and H2TiO7) and analyzed their effects on HaCaTs. There is a clear dose-dependent increase in superoxide production, caspase 8 and 9 activity, and apoptosis in HaCaTs after treatment with all three forms of TiO2; however, there is no consistent effect on cell viability and proliferation with either of these TiO2 particles. While there is data suggesting UV exposure can enhance the carcinogenic effects of TiO2, we did not observe any significant effect of UV-C exposure combined with TiO2 treatment on HaCaTs. Furthermore, TiO2-treated cells showed minimal effects on VEGF upregulation and Wnt signaling pathway thereby showing no potential effect on angiogenesis and malignant transformation. Overall, we report here an increase in apoptosis, which may be caspase 8/Fas-dependent, and that the H2TiO7 nanoparticles, despite their smaller particle size, had no significant enhanced effect on HaCaT cells as compared to Fine and Ultrafine forms of TiO2.

  19. Isolation and Characterization of Bacteria Capable of Tolerating the Extreme Conditions of Clean Room Environments▿

    PubMed Central

    La Duc, Myron T.; Dekas, Anne; Osman, Shariff; Moissl, Christine; Newcombe, David; Venkateswaran, Kasthuri

    2007-01-01

    In assessing the bacterial populations present in spacecraft assembly, spacecraft test, and launch preparation facilities, extremophilic bacteria (requiring severe conditions for growth) and extremotolerant bacteria (tolerant to extreme conditions) were isolated. Several cultivation approaches were employed to select for and identify bacteria that not only survive the nutrient-limiting conditions of clean room environments but can also withstand even more inhospitable environmental stresses. Due to their proximity to spacefaring objects, these bacteria pose a considerable risk for forward contamination of extraterrestrial sites. Samples collected from four geographically distinct National Aeronautics and Space Administration clean rooms were challenged with UV-C irradiation, 5% hydrogen peroxide, heat shock, pH extremes (pH 3.0 and 11.0), temperature extremes (4°C to 65°C), and hypersalinity (25% NaCl) prior to and/or during cultivation as a means of selecting for extremotolerant bacteria. Culture-independent approaches were employed to measure viable microbial (ATP-based) and total bacterial (quantitative PCR-based) burdens. Intracellular ATP concentrations suggested a viable microbial presence ranging from below detection limits to 106 cells/m2. However, only 0.1 to 55% of these viable cells were able to grow on defined culture medium. Isolated members of the Bacillaceae family were more physiologically diverse than those reported in previous studies, including thermophiles (Geobacillus), obligate anaerobes (Paenibacillus), and halotolerant, alkalophilic species (Oceanobacillus and Exiguobacterium). Non-spore-forming microbes (α- and β-proteobacteria and actinobacteria) exhibiting tolerance to the selected stresses were also encountered. The multiassay cultivation approach employed herein enhances the current understanding of the physiological diversity of bacteria housed in these clean rooms and leads us to ponder the origin and means of translocation of

  20. The Effect of Plant Cultivar, Growth Media, Harvest Method and Post Harvest Treatment on the Microbiology of Edible Crops

    NASA Technical Reports Server (NTRS)

    Hummerick, Mary P.; Gates, Justin R.; Nguyen, Bao-Thang; Massa, Gioia D.; Wheeler, Raymond M.

    2011-01-01

    Systems for the growth of crops in closed environments are being developed and tested for potential use in space applications to provide a source of fresh food. Plant growth conditions, growth media composition and harvest methods can have an effect on the microbial population of the plant, and therefore should be considered along with the optimization of plant growth and harvest yields to ensure a safe and palatable food crop. This work examines the effect of plant cultivar, growth media, and harvest method on plant microbial populations. Twelve varieties of leafy greens and herbs were grown on a mixture of Fafard #2 and Arcillite in the pillow root containment system currently being considered for the VEGGIE plant growth unit developed by Orbitec. In addition, ,Sierra and Outredgeous lettuce varieties were grown in three different mixtures (Fafard #2, Ardllite, and Perlite/Vermiculite). The plants were analyzed for microbial density. Two harvest methods, "cut and come again" (CACA) and terminal harvest were also compared. In one set ofexpe'riments red leaf lettuce and mizuna were grown in pots in a Biomass Production System for education. Plants were harvested every two weeks by either method. Another set of experiments was performed using the rooting pillows to grow 5 varieties of leafy greens and cut harvesting at different intervals. Radishes were harvested and replanted at two-week intervals. Results indicate up to a 3 IOglO difference in microbial counts between some varieties of plants. Rooting medium resulted in an approximately 2 IOglO lower count in the lettuce grown in arscillite then those grown in the other mixtures. Harvest method and frequency had less impact on microbial counts only showing a significant increase in one variety of plant. Post harvest methods to decrease the bacterial counts on edible crops were investigated in these and other experiments. The effectiveness of PRO-SAN and UV-C radiation is compared.

  1. Ecophysiological properties of cultivable heterotrophic bacteria and yeasts dominating in phytocenoses of Galindez Island, maritime Antarctica.

    PubMed

    Vasileva-Tonkova, Evgenia; Romanovskaya, Victoria; Gladka, Galina; Gouliamova, Dilnora; Tomova, Iva; Stoilova-Disheva, Margarita; Tashyrev, Oleksandr

    2014-04-01

    Antarctic plants are stable specific microenvironments for microbial colonization that are still less explored. In this study, we investigated cultivable heterotrophic bacteria and yeasts dominating in plant samples collected from different terrestrial biotopes near Ukrainian Antarctic Base on Galindez Island, maritime Antarctica. Phylogenetic analysis revealed affiliation of the bacterial isolates to genera Pseudomonas, Stenotrophomonas, Brevundimonas, Sporosarcina, Dermacoccus, Microbacterium, Rothia and Frondihabitans, and the yeast isolates to genera Rhodosporidium, Cryptococcus, Leucosporidiella, Candida and Exophiala. Some ecophysiological properties of isolated strains were determined that are important in response to different stresses such as psychro- and halotolerance, UV-resistance and production of hydrolytic enzymes. The majority of isolates (88 %) was found to be psychrotolerant; all are halotolerant. Significant differences in survival subsequent to UV-C radiation were observed among the isolates, as measured by culturable counts. For the bacterial isolates, lethal doses in the range 80-600 J m⁻² were determined, and for the yeast isolates--in the range 300-1,000 J m⁻². Dermacoccus profundi U9 and Candida davisiana U6 were found as most UV resistant among the bacterial and yeast isolates, respectively. Producers of caseinase, gelatinase, β-glucosidase, and cellulase were detected. To the best of our knowledge, this is the first report on isolation of UV resistant strain D. profundi, and Frondihabitans strain from Antarctica, and on detection of cellulase activity in Antarctic yeast strain C. davisiana. The results obtained contribute to clarifying adaptation strategies of Antarctic microbiota and its possible role in functional stability of Antarctic biocenoses. Stress tolerant strains were detected that are valuable for ecological and applied studies.

  2. Leptospira interrogans serovar copenhageni harbors two lexA genes involved in SOS response.

    PubMed

    Fonseca, Luciane S; da Silva, Josefa B; Milanez, Juliana S; Monteiro-Vitorello, Claudia B; Momo, Leonardo; de Morais, Zenaide M; Vasconcellos, Silvio A; Marques, Marilis V; Ho, Paulo L; da Costa, Renata M A

    2013-01-01

    Bacteria activate a regulatory network in response to the challenges imposed by DNA damage to genetic material, known as the SOS response. This system is regulated by the RecA recombinase and by the transcriptional repressor lexA. Leptospira interrogans is a pathogen capable of surviving in the environment for weeks, being exposed to a great variety of stress agents and yet retaining its ability to infect the host. This study aims to investigate the behavior of L. interrogans serovar Copenhageni after the stress induced by DNA damage. We show that L. interrogans serovar Copenhageni genome contains two genes encoding putative LexA proteins (lexA1 and lexA2) one of them being potentially acquired by lateral gene transfer. Both genes are induced after DNA damage, but the steady state levels of both LexA proteins drop, probably due to auto-proteolytic activity triggered in this condition. In addition, seven other genes were up-regulated following UV-C irradiation, recA, recN, dinP, and four genes encoding hypothetical proteins. This set of genes is potentially regulated by LexA1, as it showed binding to their promoter regions. All these regions contain degenerated sequences in relation to the previously described SOS box, TTTGN 5CAAA. On the other hand, LexA2 was able to bind to the palindrome TTGTAN10TACAA, found in its own promoter region, but not in the others. Therefore, the L. interrogans serovar Copenhageni SOS regulon may be even more complex, as a result of LexA1 and LexA2 binding to divergent motifs. New possibilities for DNA damage response in Leptospira are expected, with potential influence in other biological responses such as virulence.

  3. Xeroderma pigmentosum complementation group F: Report of a case and review of Japanese patients.

    PubMed

    Tofuku, Yukari; Nobeyama, Yoshimasa; Kamide, Ryoichi; Moriwaki, Shinichi; Nakagawa, Hidemi

    2015-09-01

    Xeroderma pigmentosum (XP) is an autosomal recessive genetic disorder characterized by extraordinary sensitivity to sunlight, resulting in cutaneous malignant tumors. Among XP, XP-F presents relatively uniquely in Japanese. To clarify the characteristics of this group, we describe a case of XP-F and review Japanese cases previously reported. A 50-year-old Japanese woman was referred to us with multiple, variously sized, light- or dark-brown macules on the face and sunlight-exposed extremities. She had experienced bulla formation with approximately 10 min of sunlight exposure during her elementary school years. Her parents had been first cousins, and her mother and sister had photosensitivity. She showed no neurological or developmental abnormalities. Ultraviolet (UV) irradiation testing revealed normal levels for minimal erythema dose with UV-A and UV-B. Sensitivity to UV-C and DNA repair ability in the patient's fibroblasts were indicated between that in normal individuals and that in an XP-A patient. Complementation assay revealed that transfection of the XPF gene led most efficient DNA repair compared with the other XP genes. Therefore, the patient was diagnosed with XP-F. Twenty-three cases of Japanese patients (six males, 17 females) with XP-F have been reported, including the present case. Our review suggested a relatively high prevalence of 50% (11/22) for cutaneous malignant tumors. A significant difference was evident in the mean age at first medical consultation between patients with cutaneous malignant tumors (53.6 years) and patients without such tumors (30.8 years). This suggests that cutaneous malignant tumors could occur in the age range of 30-50 years in XP-F patients.

  4. Effects of microinjected photoreactivating enzyme on thymine dimer removal and DNA repair synthesis in normal human and xeroderma pigmentosum fibroblasts

    SciTech Connect

    Roza, L.; Vermeulen, W.; Bergen Henegouwen, J.B.; Eker, A.P.; Jaspers, N.G.; Lohman, P.H.; Hoeijmakers, J.H. )

    1990-03-15

    UV-induced thymine dimers (10 J/m2 of UV-C) were assayed in normal human and xeroderma pigmentosum (XP) fibroblasts with a monoclonal antibody against these dimers and quantitative fluorescence microscopy. In repair-proficient cells dimer-specific immunofluorescence gradually decreased with time, reaching about 25% of the initial fluorescence after 27 h. Rapid disappearance of dimers was observed in cells which had been microinjected with yeast photoreactivating enzyme prior to UV irradiation. This photoreactivation (PHR) was light dependent and (virtually) complete within 15 min of PHR illumination. In general, PHR of dimers strongly reduces UV-induced unscheduled DNA synthesis (UDS). However, when PHR was applied immediately after UV irradiation, UDS remained unchanged initially; the decrease set in only after 30 min. When PHR was performed 2 h after UV exposure, UDS dropped without delay. An explanation for this difference is preferential removal of some type(s) of nondimer lesions, which is responsible for the PHR-resistant UDS immediately following UV irradiation. After the rapid removal of these photoproducts, the bulk of UDS is due to dimer repair. From the rapid effect of dimer removal by PHR on UDS it can be deduced that the excision of dimers up to the repair synthesis step takes considerably less than 30 min. Also in XP fibroblasts of various complementation groups the effect of PHR was investigated. The immunochemical dimer assay showed rapid PHR-dependent removal comparable to that in normal cells. However, the decrease of (residual) UDS due to PHR was absent (in XP-D) or much delayed (in XP-A and -E) compared to normal cells. This supports the idea that in these XP cells preferential repair of nondimer lesions does occur, but at a much lower rate.

  5. Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation.

    PubMed

    Ferreira, R M; Franco, E; Teixeira, A R

    1996-08-15

    The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a +5 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of 35S-labelled ribulose bisphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose bisphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose bisphosphate carboxylase. For short periods of time (< 1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose bisphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photo-synthetic tissues.

  6. ERCC4 (XPF) encodes a human nucleotide excision repair protein with eukaryotic recombination homologs.

    PubMed Central

    Brookman, K W; Lamerdin, J E; Thelen, M P; Hwang, M; Reardon, J T; Sancar, A; Zhou, Z Q; Walter, C A; Parris, C N; Thompson, L H

    1996-01-01

    ERCC4 is an essential human gene in the nucleotide excision repair (NER) pathway, which is responsible for removing UV-C photoproducts and bulky adducts from DNA. Among the NER genes, ERCC4 and ERCC1 are also uniquely involved in removing DNA interstrand cross-linking damage. The ERCC1-ERCC4 heterodimer, like the homologous Rad10-Rad1 complex, was recently found to possess an endonucleolytic activity that incises on the 5' side of damage. The ERCC4 gene, assigned to chromosome 16p13.1-p13.2, was previously isolated by using a chromosome 16 cosmid library. It corrects the defect in Chinese hamster ovary (CHO) mutants of NER complementation group 4 and is implicated in complementation group F of the human disorder xeroderma pigmentosum. We describe the ERCC4 gene structure and functional cDNA sequence encoding a 916-amino-acid protein (104 kDa), which has substantial homology with the eukaryotic DNA repair and recombination proteins MEI-9 (Drosophila melanogaster), Rad16 (Schizosaccharomyces pombe), and Rad1 (Saccharomyces cerevisiae). ERCC4 cDNA efficiently corrected mutants in rodent NER complementation groups 4 and 11, showing the equivalence of these groups, and ERCC4 protein levels were reduced in mutants of both groups. In cells of an XP-F patient, the ERCC4 protein level was reduced to less than 5%, consistent with XPF being the ERCC4 gene. The considerable identity (40%) between ERCC4 and MEI-9 suggests a possible involvement of ERCC4 in meiosis. In baboon tissues, ERCC4 was expressed weakly and was not significantly higher in testis than in nonmeiotic tissues. PMID:8887684

  7. UV filters for lighting of plants

    NASA Astrophysics Data System (ADS)

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

    1994-03-01

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

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

    PubMed Central

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

    2016-01-01

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

  9. Strain engineered high reflectivity DBRs in the deep UV

    NASA Astrophysics Data System (ADS)

    Franke, A.; Hoffmann, M. P.; Hernandez-Balderrama, L.; Kaess, F.; Bryan, I.; Washiyama, S.; Bobea, M.; Tweedie, J.; Kirste, R.; Gerhold, M.; Collazo, R.; Sitar, Z.

    2016-02-01

    The maximum achievable reflectivity of current III-nitride Bragg reflectors in the UV-C spectral range is limited due to plastic relaxation of thick multilayer structures. Cracking due to a large mismatch of the thermal expansion and lattice constants between AlxGa1-xN/AlyGa1-yN alloys of different composition and the substrate at the heterointerface is the common failure mode. Strain engineering and strain relaxation concepts by the growth on a strain reduced Al0.85Ga0.15N template and the implementation of low temperature interlayers is demonstrated. A significant enhancement of the maximum reflectivity above 97% at a resonance wavelength of 270 nm due to an increase of the critical thickness of our AlN/Al0.65Ga0.35N DBRs to 1.45 μm (25.5 pairs) prove their potential. By comparing the growth of identical Bragg reflectors on different pseudo-templates, the accumulated mismatch strain energy in the DBR, not the dislocation density provided by the template/substrate, was identified to limit the critical thickness. To further enhance the reflectivity low temperature interlays were implemented into the DBR to partially relief the misfit strain. Relaxation is enabled by the nucleation of small surface domains facilitating misfit dislocation injection and glide. Detailed structural and optical investigations will be conducted to prove the influence of the LT-AlN interlayers on the strain state, structural integrity and reflectivity properties. Coherent growth and no structural and optical degradation of the Bragg mirror properties was observed proving the fully applicability of the relaxation concept to fabricate thick high reflectivity DBR and vertical cavity laser structures.

  10. UV filters for lighting of plants

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  11. Reference Gene Validation for Quantitative RT-PCR during Biotic and Abiotic Stresses in Vitis vinifera

    PubMed Central

    Borges, Alexandre Filipe; Fonseca, Catarina; Ferreira, Ricardo Boavida; Lourenço, Ana Maria; Monteiro, Sara

    2014-01-01

    Grapevine is one of the most cultivated fruit crop worldwide with Vitis vinifera being the species with the highest economical importance. Being highly susceptible to fungal pathogens and increasingly affected by environmental factors, it has become an important agricultural research area, where gene expression analysis plays a fundamental role. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is currently amongst the most powerful techniques to perform gene expression studies. Nevertheless, accurate gene expression quantification strongly relies on appropriate reference gene selection for sample normalization. Concerning V. vinifera, limited information still exists as for which genes are the most suitable to be used as reference under particular experimental conditions. In this work, seven candidate genes were investigated for their stability in grapevine samples referring to four distinct stresses (Erysiphe necator, wounding and UV-C irradiation in leaves and Phaeomoniella chlamydospora colonization in wood). The expression stability was evaluated using geNorm, NormFinder and BestKeeper. In all cases, full agreement was not observed for the three methods. To provide comprehensive rankings integrating the three different programs, for each treatment, a consensus ranking was created using a non-weighted unsupervised rank aggregation method. According to the last, the three most suitable reference genes to be used in grapevine leaves, regardless of the stress, are UBC, VAG and PEP. For the P. chlamydospora treatment, EF1, CYP and UBC were the best scoring genes. Acquaintance of the most suitable reference genes to be used in grapevine samples can contribute for accurate gene expression quantification in forthcoming studies. PMID:25340748

  12. Effects of titanium dioxide nanoparticles on human keratinocytes

    PubMed Central

    Wright, Clayton; Iyer, Anand Krishnan V.; Wang, Liying; Wu, Nianqiang; Yakisich, Juan S.; Rojanasakul, Yon; Azad, Neelam

    2016-01-01

    Titanium dioxide (TiO2) is a ubiquitous whitening compound widely used in topical products such as sunscreens, lotions and facial creams. The damaging health effects of TiO2 inhalation has been widely studied in rats, mice and humans showing oxidative stress increase, DNA damage, cell death and inflammatory gene upregulation in lung and throat cells; however, the effects on skin cells from long-term topical use of various products remain largely unknown. In this study, we assessed the effect of specific TiO2 nanoparticles (H2TiO7) on a human keratinocyte cell line (HaCaT). We performed a comparative analysis using three TiO2 particles varying in size (Fine, Ultrafine and H2TiO7) and analyzed their effects on HaCaTs. There is a clear dose-dependent increase in superoxide production, caspase 8 and 9 activity, and apoptosis in HaCaTs after treatment with all three forms of TiO2; however, there is no consistent effect on cell viability and proliferation with either of these TiO2 particles. While there is data suggesting UV exposure can enhance the carcinogenic effects of TiO2, we did not observe any significant effect of UV-C exposure combined with TiO2 treatment on HaCaTs. Furthermore, TiO2-treated cells showed minimal effects on VEGF upregulation and Wnt signaling pathway thereby showing no potential effect on angiogenesis and malignant transformation. Overall, we report here an increase in apoptosis, which may be caspase 8/Fas-dependent, and that the H2TiO7 nanoparticles, despite their smaller particle size, had no significant enhanced effect on HaCaT cells as compared to Fine and Ultrafine forms of TiO2. PMID:27310834

  13. A role for histone H2B during repair of UV-induced DNA damage in Saccharomyces cerevisiae.

    PubMed Central

    Martini, Emmanuelle M D; Keeney, Scott; Osley, Mary Ann

    2002-01-01

    To investigate the role of the nucleosome during repair of DNA damage in yeast, we screened for histone H2B mutants that were sensitive to UV irradiation. We have isolated a new mutant, htb1-3, that shows preferential sensitivity to UV-C. There is no detectable difference in bulk chromatin structure or in the number of UV-induced cis-syn cyclobutane pyrimidine dimers (CPD) between HTB1 and htb1-3 strains. These results suggest a specific effect of this histone H2B mutation in UV-induced DNA repair processes rather than a global effect on chromatin structure. We analyzed the UV sensitivity of double mutants that contained the htb1-3 mutation and mutations in genes from each of the three epistasis groups of RAD genes. The htb1-3 mutation enhanced UV-induced cell killing in rad1Delta and rad52Delta mutants but not in rad6Delta or rad18Delta mutants, which are defective in postreplicational DNA repair (PRR). When combined with other mutations that affect PRR, the histone mutation increased the UV sensitivity of strains with defects in either the error-prone (rev1Delta) or error-free (rad30Delta) branches of PRR, but did not enhance the UV sensitivity of a strain with a rad5Delta mutation. When combined with a ubc13Delta mutation, which is also epistatic with rad5Delta, the htb1-3 mutation enhanced UV-induced cell killing. These results suggest that histone H2B acts in a novel RAD5-dependent branch of PRR. PMID:11973294

  14. Suitability of different Escherichia coli enumeration techniques to assess the microbial quality of different irrigation water sources.

    PubMed

    Truchado, P; Lopez-Galvez, F; Gil, M I; Pedrero-Salcedo, F; Alarcón, J J; Allende, A

    2016-09-01

    The use of fecal indicators such as Escherichia coli has been proposed as a potential tool to characterize microbial contamination of irrigation water. Recently, not only the type of microbial indicator but also the methodologies used for enumeration have been called into question. The goal of this study was to assess the microbial quality of different water sources for irrigation of zucchini plants by using E. coli as an indicator of fecal contamination and the occurrence of foodborne pathogens. Three water sources were evaluated including reclaimed secondary treated water (RW-2), reclaimed tertiary UV-C treated water (RW-3) and surface water (SW). The suitability of two E. coli quantification techniques (plate count and qPCR) was examined for irrigation water and fresh produce. E. coli levels using qPCR assay were significantly higher than that obtained by plate count in all samples of irrigation water and fresh produce. The microbial quality of water samples from RW-2 was well predicted by qPCR, as the presence of foodborne pathogens were positively correlated with high E. coli levels. However, differences in the water characteristics influenced the suitability of qPCR as a tool to predict potential contamination in irrigation water. No significant differences were obtained between the number of cells of E. coli from RW-2 and RW-3, probably due to the fact that qPCR assay cannot distinguish between viable and dead cells. These results indicated that the selection of the most suitable technique for enumeration of indicator microorganisms able to predict potential presence of fecal contamination might be influenced by the water characteristics.

  15. Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants?

    PubMed

    Cristale, Joyce; Ramos, Dayana D; Dantas, Renato F; Machulek Junior, Amilcar; Lacorte, Silvia; Sans, Carme; Esplugas, Santiago

    2016-01-01

    This study aims to determine the occurrence of 10 OPFRs (including chlorinated, nonchlorinated alkyl and aryl compounds) in influent, effluent wastewaters and partitioning into sludge of 5 wastewater treatment plants (WWTP) in Catalonia (Spain). All target OPFRs were detected in the WWTPs influents, and the total concentration ranged from 3.67 µg L(-1) to 150 µg L(-1). During activated sludge treatment, most OPFRs were accumulated in the sludge at concentrations from 35.3 to 9980 ng g(-1) dw. Chlorinated compounds tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2,3-dichloropropyl) phosphate (TDCPP) were not removed by the conventional activated sludge treatment and they were released by the effluents at approximately the same inlet concentration. On the contrary, aryl compounds tris(methylphenyl) phosphate (TMPP) and 2-ethylhexyl diphenyl phosphate (EHDP) together with alkyl tris(2-ethylhexyl) phosphate (TEHP) were not detected in any of the effluents. Advanced oxidation processes (UV/H2O2 and O3) were applied to investigate the degradability of recalcitrant OPFRs in WWTP effluents. Those detected in the effluent sample (TCEP, TCIPP, TDCPP, tributyl phosphate (TNBP), tri-iso-butyl phosphate (TIBP) and tris(2-butoxyethyl) phosphate (TBOEP)) had very low direct UV-C photolysis rates. TBOEP, TNBP and TIBP were degraded by UV/H2O2 and O3. Chlorinated compounds TCEP, TDCPP and TCIPP were the most recalcitrant OPFR to the advanced oxidation processes applied. The study provides information on the partitioning and degradability pathways of OPFR within conventional activated sludge WWTPs.

  16. Extracellular terpenoid hydrocarbon extraction and quantitation from the green microalgae Botryococcus braunii var. Showa.

    PubMed

    Eroglu, Ela; Melis, Anastasios

    2010-04-01

    Mechanical fractionation and aqueous or aqueous/organic two-phase partition approaches were applied for extraction and separation of extracellular terpenoid hydrocarbons from Botryococcus braunii var. Showa. A direct spectrophotometric method was devised for the quantitation of botryococcene and associated carotenoid hydrocarbons extracted by this method. Separation of extracellular botryococcene hydrocarbons from the Botryococcus was achieved upon vortexing of the micro-colonies with glass beads, either in water followed by buoyant density equilibrium to separate hydrocarbons from biomass, or in the presence of heptane as a solvent, followed by aqueous/organic two-phase separation of the heptane-solubilized hydrocarbons (upper phase) from the biomass (lower aqueous phase). Spectral analysis of the upper heptane phase revealed the presence of two distinct compounds, one absorbing in the UV-C, attributed to botryococcene(s), the other in the blue region of the spectrum, attributed to a carotenoid. Specific extinction coefficients were developed for the absorbance of triterpenes at 190nm (epsilon = 90 +/- 5 mM(-1) cm(-1)) and carotenoids at 450 nm (epsilon=165+/-5mM(-1) cm(-1)) in heptane. This enabled application of a direct spectrophotometric method for the quantitation of water- or heptane-extractable botryococcenes and carotenoids. B. braunii var. Showa constitutively accumulates approximately 30% of the dry biomass as extractable (extracellular) botryococcenes, and approximately 0.2% of the dry biomass in the form of a carotenoid. It was further demonstrated that heat-treatment of the Botryococcus biomass substantially accelerates the rate and yield of the extraction process. Advances in this work serve as foundation for a cyclic Botryococcus growth, non-toxic extraction of extracellular hydrocarbons, and return of the hydrocarbon-depleted biomass to growth conditions for further product generation.

  17. Genetic diversity of stilbene metabolism in Vitis sylvestris

    PubMed Central

    Duan, Dong; Halter, David; Baltenweck, Raymonde; Tisch, Christine; Tröster, Viktoria; Kortekamp, Andreas; Hugueney, Philippe; Nick, Peter

    2015-01-01

    Stilbenes, as important secondary metabolites of grapevine, represent central phytoalexins and therefore constitute an important element of basal immunity. In this study, potential genetic variation in Vitis vinifera ssp. sylvestris, the ancestor of cultivated grapevine, was sought with respect to their output of stilbenes and potential use for resistance breeding. Considerable variation in stilbene inducibility was identified in V. vinifera ssp. sylvestris. Genotypic differences in abundance and profiles of stilbenes that are induced in response to a UV-C pulse are shown. Two clusters of stilbene ‘chemovars’ emerged: one cluster showed quick and strong accumulation of stilbenes, almost exclusively in the form of non-glycosylated resveratrol and viniferin, while the second cluster accumulated fewer stilbenes and relatively high proportions of piceatannol and the glycosylated piceid. For all 86 genotypes, a time dependence of the stilbene pattern was observed: piceid, resveratrol, and piceatannol accumulated earlier, whereas the viniferins were found later. It was further observed that the genotypic differences in stilbene accumulation were preceded by differential accumulation of the transcripts for chalcone synthase (CHS) and stilbene-related genes: phenylalanine ammonium lyase (PAL), stilbene synthase (StSy), and resveratrol synthase (RS). A screen of the population with respect to susceptibility to downy mildew of grapevine (Plasmopara viticola) revealed considerable variability. The subpopulation of genotypes with high stilbene inducibility was significantly less susceptible as compared with low-stilbene genotypes, and for representative genotypes it could be shown that the inducibility of stilbene synthase by UV correlated with the inducibility by the pathogen. PMID:25873669

  18. Norovirus and MS2 inactivation kinetics of UV-A and UV-B with and without TiO2.

    PubMed

    Lee, Jung Eun; Ko, GwangPyo

    2013-10-01

    Germicidal ultraviolet, such as 254-nm UV-C, is a common method of disinfection of pathogenic enteric viruses. However, the disinfection efficacies of UV-A or -B in terms of inactivating waterborne viruses such as norovirus have not been characterized. We evaluated the inactivation kinetics of MS2 bacteriophage and murine norovirus (MNV), a surrogate of human norovirus (NoV), by UV-A and -B. In addition to UV disinfection, we further investigated whether the presence of TiO2 could enhance the virus inactivation kinetics of UV-A and -B. Both MS2 and MNV were highly resistant to UV-A. However, the addition of TiO2 enhanced the efficacy of UV-A for inactivating these viruses. UV-A dose of 1379 mJ/cm(2) resulted in a 4 log10 reduction. In comparison, UV-B alone effectively inactivated both MS2 and MNV, as evidenced by the 4 log10 reduction by 367 mJ/cm(2) of UV-B. The addition of TiO2 increased the inactivation of MS2; however, it did not significantly increase the efficacy of UV-B disinfection for inactivating MNV. When these treatments were applied to field water such as groundwater, the results were generally consistent with the laboratory findings. Our results clearly indicated that UV-B is useful for the disinfection of waterborne norovirus. However, MNV was quite resistant to UV-A, and UV-A effectively inactivated the tested viruses only when used in combination with TiO2.

  19. TiO2 and SnO2 magnetic nanocomposites: influence of semiconductors and synthetic methods on photoactivity.

    PubMed

    Mourão, Henrique A J L; Ribeiro, Caue

    2011-09-01

    A number of reports have been published on use of TiO2 in thin films, magnetic nanocomposites, or heterostructures such as TiO2/Ag and TiO2/SnO2, as catalysts for water decontamination. Hence, semiconductor materials such as SnO2, associated with TiO2 in such nanocomposites, should be assessed in depth for such applications, especially those involving complex structures, such as magnetic photocatalytic nanocomposites. The present study describes the synthesis, characterization and testing of the photocatalytic potential of TiO2 or SnO2 magnetic nanocomposites obtained by the polymeric precursor and the hydrolytic sol-gel methods. The nanocomposites TiO2/CoFe2O4 and SnO2/CoFe2O4 were synthesized from polymeric precursors while TiO2/Fe3O4 and SnO2/Fe3O4 were synthesized by the hydrolytic sol-gel method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (FEG/SEM) and transmission electron microscopy (TEM). The photocatalytic potentials were evaluated by rhodamine B dye photodegradation under UV-C radiation. Compared to SnO2, the nanocomposites with a coating of TiO2 were found to show better photocatalytic activity, but the SnO2 magnetic nanocomposites showed some photocatalytic activity, even though SnO2 is reported to be inactive for these purposes. As for the synthesis method, the nanocomposites obtained from polymeric precursors had smaller surface areas, but higher photocatalytic activity, than those obtained by the hydrolytic sol-gel method. This observation was attributed to the higher crystallinity and a more active surface resulting from calcination of the polymeric precursor material.

  20. Effect of iron ion on doxycycline photocatalytic and Fenton-based autocatatalytic decomposition.

    PubMed

    Bolobajev, Juri; Trapido, Marina; Goi, Anna

    2016-06-01

    Doxycycline plays a key role in Fe(III)-to-Fe(II) redox cycling and therefore in controlling the overall reaction rate of the Fenton-based process (H2O2/Fe(III)). This highlights the autocatalytic profile of doxycycline degradation. Ferric iron reduction in the presence of doxycycline relied on doxycycline-to-Fe(III) complex formation with an ensuing reductive release of Fe(II). The lower ratio of OH-to-contaminant in an initial H2O2/Fe(III) oxidation step than in that of classical Fenton (H2O2/Fe(II)) decreased the doxycycline degradation rate. The quantum yield of doxycycline in direct UV-C photolysis was 3.1 × 10(-3) M E(-1). In spite of doxycycline-Fe(III) complexes could produce the adverse effect on the doxycycline degradation in the UV/Fe(III) system some acceleration of the rate was observed upon irradiation of the Fe(III)-hydroxy complex. Acidic reaction media (pH 3.0) and the molar ratio of DC/Fe(III) = 2/1 favored the complex formation. Doxycycline close degradation rates and complete mineralization achieved for 120 min (Table 1) with both UV/H2O2 and UV/H2O2/Fe(III) indicated the unsubstantial role of the reduction of Fe(III) to Fe(II) in UV/H2O2/Fe(III) system efficacy. Thus, factors such as doxycycline's ability to form complexes with ferric iron and the ability of complexes to participate in a reductive pathway should be considered at a technological level in process optimization, with chemistry based on iron ion catalysis to enhance the doxycycline oxidative pathway.

  1. Irradiation of Yarrowia lipolytica NRRL YB-567 creating novel strains with enhanced ammonia and oil production on protein and carbohydrate substrates.

    PubMed

    Lindquist, Mitch R; López-Núñez, Juan Carlos; Jones, Marjorie A; Cox, Elby J; Pinkelman, Rebecca J; Bang, Sookie S; Moser, Bryan R; Jackson, Michael A; Iten, Loren B; Kurtzman, Cletus P; Bischoff, Kenneth M; Liu, Siqing; Qureshi, Nasib; Tasaki, Kenneth; Rich, Joseph O; Cotta, Michael A; Saha, Badal C; Hughes, Stephen R

    2015-11-01

    Increased interest in sustainable production of renewable diesel and other valuable bioproducts is redoubling efforts to improve economic feasibility of microbial-based oil production. Yarrowia lipolytica is capable of employing a wide variety of substrates to produce oil and valuable co-products. We irradiated Y. lipolytica NRRL YB-567 with UV-C to enhance ammonia (for fertilizer) and lipid (for biodiesel) production on low-cost protein and carbohydrate substrates. The resulting strains were screened for ammonia and oil production using color intensity of indicators on plate assays. Seven mutant strains were selected (based on ammonia assay) and further evaluated for growth rate, ammonia and oil production, soluble protein content, and morphology when grown on liver infusion medium (without sugars), and for growth on various substrates. Strains were identified among these mutants that had a faster doubling time, produced higher maximum ammonia levels (enzyme assay) and more oil (Sudan Black assay), and had higher maximum soluble protein levels (Bradford assay) than wild type. When grown on plates with substrates of interest, all mutant strains showed similar results aerobically to wild-type strain. The mutant strain with the highest oil production and the fastest doubling time was evaluated on coffee waste medium. On this medium, the strain produced 0.12 g/L ammonia and 0.20 g/L 2-phenylethanol, a valuable fragrance/flavoring, in addition to acylglycerols (oil) containing predominantly C16 and C18 residues. These mutant strains will be investigated further for potential application in commercial biodiesel production.

  2. Synthesis of Fe-doped Bi2O3 nanocatalyst and its sonophotocatalytic activity on synthetic dye and real textile wastewater.

    PubMed

    Dinesh, G Kumaravel; Anandan, Sambandam; Sivasankar, Thirugnanasambandam

    2016-10-01

    The catalysts such as Fe, Bi2O3, and Fe-doped Bi2O3 were synthesized for the sonophotocatalytic treatment of synthetic dye and real textile wastewater. The resultant catalysts were characterized for its size and uniform shape using x-ray diffractogram (XRD) and scanning electron microscopy (SEM) which signified the nanorod shape formed Bi2O3. The higher ultraviolet light absorbance capacity of the catalysts was also evident using diffuse reflectance spectroscopy (DRS). Initially, the effect of conventional parameters such as initial pH, gas bubbling (argon, oxygen, air and nitrogen) and oxidant addition (H2O2 and peroxymonosulfate) in the presence of sonolysis (22 and 37 kHz frequency) and photolysis (UV-C light) on 10 ppm Basic Brown 1 dye was studied. The results showed that highest decolorization of 62 % was attained for 3 g/L peroxymonosulfate under 37 kHz frequency sonolysis treatment. Secondly, with the catalyst study, highest of 46 % dye color removal was obtained with 4 g/L Fe under 37 kHz frequency sonolysis treatment. The sonophotocatalytic treatment of dye with Fe-doped Bi2O3 catalyst in combination with peroxymonosulfate showed highest color removal of 99 %. Finally, the sonophotocatalytic treatment of real textile wastewater in the presence of 3 g/L Fe-doped Bi2O3 and 6 g/L peroxymonosulfate reduced the total organic carbon (TOC) and chemical oxygen demand (COD) level to 77 and 91 %, respectively, in 180 min. The reported treatment process was found to treat the synthetic dye and real textile wastewater effectively.

  3. Gas-phase advanced oxidation for effective, efficient in situ control of pollution.

    PubMed

    Johnson, Matthew S; Nilsson, Elna J K; Svensson, Erik A; Langer, Sarka

    2014-01-01

    In this article, gas-phase advanced oxidation, a new method for pollution control building on the photo-oxidation and particle formation chemistry occurring in the atmosphere, is introduced and characterized. The process uses ozone and UV-C light to produce in situ radicals to oxidize pollution, generating particles that are removed by a filter; ozone is removed using a MnO2 honeycomb catalyst. This combination of in situ processes removes a wide range of pollutants with a comparatively low specific energy input. Two proof-of-concept devices were built to test and optimize the process. The laboratory prototype was built of standard ventilation duct and could treat up to 850 m(3)/h. A portable continuous-flow prototype built in an aluminum flight case was able to treat 46 m(3)/h. Removal efficiencies of >95% were observed for propane, cyclohexane, benzene, isoprene, aerosol particle mass, and ozone for concentrations in the range of 0.4-6 ppm and exposure times up to 0.5 min. The laboratory prototype generated a OH(•) concentration derived from propane reaction of (2.5 ± 0.3) × 10(10) cm(-3) at a specific energy input of 3 kJ/m(3), and the portable device generated (4.6 ± 0.4) × 10(9) cm(-3) at 10 kJ/m(3). Based on these results, in situ gas-phase advanced oxidation is a viable control strategy for most volatile organic compounds, specifically those with a OH(•) reaction rate higher than ca. 5 × 10(-13) cm(3)/s. Gas-phase advanced oxidation is able to remove compounds that react with OH and to control ozone and total particulate mass. Secondary pollution including formaldehyde and ultrafine particles might be generated, depending on the composition of the primary pollution.

  4. Application of GaN-based ultraviolet-C light emitting diodes--UV LEDs--for water disinfection.

    PubMed

    Würtele, M A; Kolbe, T; Lipsz, M; Külberg, A; Weyers, M; Kneissl, M; Jekel, M

    2011-01-01

    GaN-based ultraviolet-C (UV-C) light emitting diodes (LEDs) are of great interest for water disinfection. They offer significant advantages compared to conventional mercury lamps due to their compact form factor, low power requirements, high efficiency, non-toxicity, and overall robustness. However, despite the significant progress in the performance of semiconductor based UV LEDs that has been achieved in recent years, these devices still suffer from low emission power and relatively short lifetimes. Even the best UV LEDs exhibit external quantum efficiencies of only 1-2%. The objective of this study was to investigate the suitability of GaN-based UV LEDs for water disinfection. The investigation included the evaluation of the performance characteristics of UV LEDs at different operating conditions as well as the design of a UV LED module in view of the requirements for water treatment applications. Bioanalytical testing was conducted using Bacillus subtilis spores as test organism and UV LED modules with emission wavelengths of 269 nm and 282 nm. The results demonstrate the functionality of the developed UV LED disinfection modules. GaN-based UV LEDs effectively inactivated B. subtilis spores during static and flow-through tests applying varying water qualities. The 269 nm LEDs reached a higher level of inactivation than the 282 nm LEDs for the same applied fluence. The lower inactivation achieved by the 282 nm LEDs was compensated by their higher photon flux. First flow-through tests indicate a linear correlation between inactivation and fluence, demonstrating a well designed flow-through reactor. With improved light output and reduced costs, GaN-based UV LEDs can provide a promising alternative for decentralised and mobile water disinfection systems.

  5. Heterogeneous photocatalytic disinfection of wash waters from the fresh-cut vegetable industry.

    PubMed

    Selma, María Victoria; Allende, Ana; López-Gálvez, Francisco; Conesa, María Angeles; Gil, María Isabel

    2008-02-01

    The effectiveness of photocatalytic disinfection for control of natural and potentially pathogenic microflora in wash waters used for fresh-cut vegetables was evaluated. Wash waters for lettuce, escarole, chicory, carrot, onion, and spinach from a fresh-cut vegetable processing plant were treated with a titanium dioxide (TiO2) photocatalytic system. The vegetable wash waters were impelled out with a pump at a flow rate of 1,000 liters/h and conducted through a stainless steel circuit to the filtration system to reach the TiO2 photocatalyst fiber, which was illuminated with a 40-W UV-C lamp. The microbial and physicochemical qualities of the wash water were analyzed. Heterogeneous photocatalysis was an effective disinfection method, reducing counts of bacteria, molds, and yeasts. Most of the treated wash waters had total bacteria reductions of 4.1 +/- 1.3 to 4.8 +/- 0.4 log CFU/ml after 10 min of treatment when compared with untreated water. Higher decontamination efficacy was observed in carrot wash water (6.2 +/- 0.1-log reductions), where turbidity and organic matter were lower than those in the wash waters for other vegetables. The tested heterogeneous photocatalytic system also was effective for reducing water turbidity, although chemical oxygen demand was unaffected after the treatments. The efficacy of the photocatalytic system for reducing microbial load depended on the physicochemical characteristics of the wash water, which depended on the vegetable being washed. The conclusions derived from this study illustrate that implementation of a heterogeneous photocatalytic system in the fresh-cut vegetable washing processes could allow the reuse of wash water.

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

    PubMed

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

    2016-01-01

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

  7. Photochemically induced deposition of protective alumina coatings onto UV emitting phosphors for Xe excimer discharge lamps

    SciTech Connect

    Broxtermann, Mike Jüstel, Thomas

    2016-08-15

    Highlights: • A UV-reactor for the pH induced precipitation of inorganic material is described. • The photolysis of Azide (N{sub 3}{sup −}) leads to a steady pH increase used for precipitation. • A UV induced Al(OH){sub 3} precipitation is used to craft Al{sub 2}O{sub 3} coatings onto YPO{sub 4}:Bi. • The influence of Al{sub 2}O{sub 3} coated onto YPO{sub 4}:Bi with different thicknesses is discussed. • SEM, VUV-spectroscopy and ESA measurements were performed on Al{sub 2}O{sub 3} coated samples. - Abstract: This work concerns the particle coating of the UV-C emitting phosphor YPO{sub 4}:Bi, targeting a stability enhancement of the phosphor material for Xe excimer lamp operation. To this end, the material is coated by the wide band gap material Al{sub 2}O{sub 3}. In order to obtain a thin and homogeneous coating layer, a novel process based on the photochemical cleavage of NaN{sub 3} in water was developed. This results in a slow and continuous enhancement of the pH value due to ongoing NaOH formation, which results in the precipitation of Al(OH){sub 3} from an Al{sub 2}(SO{sub 4}){sub 3} {sub ×} 18H{sub 2}O solution. It turned out that the obtained particle coatings are of much better quality, i.e. homogeneity, compared to coatings made from a wet-chemical homogeneous precipitation process. The morphology and electrochemical properties of Al{sub 2}O{sub 3} coated YPO{sub 4}:Bi are discussed on the basis of optical spectroscopy, ESA measurements, and SEM/EDX investigations.

  8. Persistence of biomarker ATP and ATP-generating capability in bacterial cells and spores contaminating spacecraft materials under earth conditions and in a simulated martian environment.

    PubMed

    Fajardo-Cavazos, Patricia; Schuerger, Andrew C; Nicholson, Wayne L

    2008-08-01

    Most planetary protection research has concentrated on characterizing viable bioloads on spacecraft surfaces, developing techniques for bioload reduction prior to launch, and studying the effects of simulated martian environments on microbial survival. Little research has examined the persistence of biogenic signature molecules on spacecraft materials under simulated martian surface conditions. This study examined how endogenous adenosine-5'-triphosphate (ATP) would persist on aluminum coupons under simulated martian conditions of 7.1 mbar, full-spectrum simulated martian radiation calibrated to 4 W m(-2) of UV-C (200 to 280 nm), -10 degrees C, and a Mars gas mix of CO(2) (95.54%), N(2) (2.7%), Ar (1.6%), O(2) (0.13%), and H(2)O (0.03%). Cell or spore viabilities of Acinetobacter radioresistens, Bacillus pumilus, and B. subtilis were measured in minutes to hours, while high levels of endogenous ATP were recovered after exposures of up to 21 days. The dominant factor responsible for temporal reductions in viability and loss of ATP was the simulated Mars surface radiation; low pressure, low temperature, and the Mars gas composition exhibited only slight effects. The normal burst of endogenous ATP detected during spore germination in B. pumilus and B. subtilis was reduced by 1 or 2 orders of magnitude following, respectively, 8- or 30-min exposures to simulated martian conditions. The results support the conclusion that endogenous ATP will persist for time periods that are likely to extend beyond the nominal lengths of most surface missions on Mars, and planetary protection protocols prior to launch may require additional rigor to further reduce the presence and abundance of biosignature molecules on spacecraft surfaces.

  9. Analysis of Ar plasma jets induced by single and double dielectric barrier discharges at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Judée, F.; Merbahi, N.; Wattieaux, G.; Yousfi, M.

    2016-09-01

    The aim is the comparison of different plasma parameters of single and double dielectric barrier discharge plasma jet configurations (S-DBD and D-DBD) which are potentially usable in biomedical applications. Both configurations are studied in terms of electric field distribution, electrical discharge characteristics, plasma parameters (estimated by optical emission spectroscopy analysis), and hydrodynamics of the plasma jet for electrical parameters of power supplies corresponding to an applied voltage of 10 kV, pulse duration of 1 μs, frequency of 9.69 kHz, and Ar flow of 2 l/min. We observed that the D-DBD configuration requires half the electrical power one needs to provide in the S-DBD case to generate a plasma jet with similar characteristics: excitation temperature around 4700 K, electron density around 2.5 × 1014 cm-3, gas temperature of about 320 K, a relatively high atomic oxygen concentration reaching up to 1000 ppm, the presence of reactive oxygen and nitrogen species (nitric oxide, hydroxyl radical, and atomic oxygen), and an irradiance in the UV-C range of about 20 μW cm-2. Moreover, it has been observed that D-DBD plasma jet is more sensitive to short pulse durations, probably due to the charge accumulation over the dielectric barrier around the internal electrode. This results in a significantly longer plasma length in the D-DBD configuration than in the S-DBD one up to a critical flow rate (2.25 l/min) before the occurrence of turbulence in the D-DBD case. Conversely, ionization wave velocities are significantly higher in the S-DBD setup (3.35 × 105 m/s against 1.02 × 105 m/s for D-DBD), probably due to the higher electrostatic field close to the high voltage electrode in the S-DBD plasma jet.

  10. Assessment of degradation byproducts and NDMA formation potential during UV and UV/H2O2 treatment of doxylamine in the presence of monochloramine.

    PubMed

    Farré, Maria José; Radjenovic, Jelena; Gernjak, Wolfgang

    2012-12-04

    UV-C radiation is the U.S. EPA recommended technology to remove N-nitrosodimethylamine (NDMA) during drinking and recycled water production. Frequently, H(2)O(2) is added to the treatment to remove other recalcitrant compounds and to prevent NDMA reformation. However, the transformation of NDMA precursors during the UV and UV/H(2)O(2) process and the consequences for NDMA formation potential are currently not well understood, in particular in the presence of monochloramine. In this study, doxylamine has been chosen as a model compound to elucidate its degradation byproducts in the UV and UV/H(2)O(2) process and correlate those with changes to the NDMA formation potential. This study shows that during UV treatment in the presence and absence of monochloramine, NDMA formation potential can be halved. However, an increase of more than 30% was observed when hydrogen peroxide was added. Ultrafast liquid chromatography coupled to quadrupole-linear ion trap mass spectrometer was used for screening and structural elucidation of degradation byproducts identifying 21 chemical structures from the original parent compound. This work shows that further oxidation of NDMA precursors does not necessarily lead to a decrease in NDMA formation potential. Degradation byproducts with increased electron density in the vicinity of the dimethylamino moiety, for example induced by hydroxylation, may have a higher yield of nucleophilic substitution and subsequent NDMA formation compared to the parent compound during chloramination. This work demonstrates the need to consider the formation of oxidation byproducts and associated implications for the control and management of NDMA formation in downstream processes and distribution when integrating oxidative treatments into a treatment train generating either drinking water or recycled water for potable reuse.

  11. Cellular stress rather than stage of the cell cycle enhances the replication and plating efficiencies of herpes simplex virus type 1 ICP0- viruses.

    PubMed

    Bringhurst, Ryan M; Schaffer, Priscilla A

    2006-05-01

    This lab reported previously that the plating efficiency of a herpes simplex virus type 1 ICP0-null mutant was enhanced upon release from an isoleucine block which synchronizes cells to G1 phase (W. Cai and P. A. Schaffer, J. Virol. 65:4078-4090, 1991). Peak plating efficiency occurred as cells cycled out of G1 and into S phase, suggesting that the enhanced plating efficiency was due to cellular activities present in late G1/early S phase. We have found, however, that the enhanced plating efficiency did not occur when cells were synchronized by alternative methods. We now report that the plating efficiency of ICP0- viruses is not enhanced at a particular stage of the cell cycle but rather is enhanced by specific cellular stresses. Both the plating and replication efficiencies of ICP0- viruses were enhanced as much as 25-fold to levels similar to that of wild-type virus when monolayers were heat shocked prior to infection. In addition to heat shock, UV-C irradiation but not cold shock of monolayers prior to infection resulted in enhanced plating efficiency. We further report that the effect of cellular stress is transient and that cell density rather than age of the monolayers is the primary determinant of ICP0- virus plating efficiency. As both cell stress and ICP0 are required for efficient reactivation from latency, the identification of cellular activities that complement ICP0- viruses may lead to the identification of cellular activities that are important for reactivation from neuronal latency.

  12. Persistence of Biomarker ATP and ATP-Generating Capability in Bacterial Cells and Spores Contaminating Spacecraft Materials under Earth Conditions and in a Simulated Martian Environment▿

    PubMed Central

    Fajardo-Cavazos, Patricia; Schuerger, Andrew C.; Nicholson, Wayne L.

    2008-01-01

    Most planetary protection research has concentrated on characterizing viable bioloads on spacecraft surfaces, developing techniques for bioload reduction prior to launch, and studying the effects of simulated martian environments on microbial survival. Little research has examined the persistence of biogenic signature molecules on spacecraft materials under simulated martian surface conditions. This study examined how endogenous adenosine-5′-triphosphate (ATP) would persist on aluminum coupons under simulated martian conditions of 7.1 mbar, full-spectrum simulated martian radiation calibrated to 4 W m−2 of UV-C (200 to 280 nm), −10°C, and a Mars gas mix of CO2 (95.54%), N2 (2.7%), Ar (1.6%), O2 (0.13%), and H2O (0.03%). Cell or spore viabilities of Acinetobacter radioresistens, Bacillus pumilus, and B. subtilis were measured in minutes to hours, while high levels of endogenous ATP were recovered after exposures of up to 21 days. The dominant factor responsible for temporal reductions in viability and loss of ATP was the simulated Mars surface radiation; low pressure, low temperature, and the Mars gas composition exhibited only slight effects. The normal burst of endogenous ATP detected during spore germination in B. pumilus and B. subtilis was reduced by 1 or 2 orders of magnitude following, respectively, 8- or 30-min exposures to simulated martian conditions. The results support the conclusion that endogenous ATP will persist for time periods that are likely to extend beyond the nominal lengths of most surface missions on Mars, and planetary protection protocols prior to launch may require additional rigor to further reduce the presence and abundance of biosignature molecules on spacecraft surfaces. PMID:18567687

  13. Bulk Geochemical Data of Fossil Wood from the Middle Jurassic Clays of Poland

    NASA Astrophysics Data System (ADS)

    Smolarek, Justyna

    2012-01-01

    ści TOC dla badanych próbek wahają się w szerokim zakresie od 1,06% do 68,50 %. Największa ilość TOC występuje w nie zmineralizowanych lub słabo zmineralizowanych próbkach drewna. Większość próbek to zmineralizowane fragmenty drewna, pokazując wartości TOC w zakresie od 2% - 10%. Zawartość procentowa węglanów w badanych próbkach znajduje się w szerokim zakresie od mniej niż 1% CaCO3 do ponad 85% CaCO3. Procentowa zawartość siarki całkowitej jest bardzo zróżnicowana i nie wykazuje zbieżności z innymi danymi, takimi jak TOC czy zawartość węglanów, itp. W odróżnieniu od środkowojurajskich iłów, gdzie długołańcuchowe i krótkołańcuchowe n-alkany występują w podobnych stężeniach , w próbkach drewna zawsze przewyższają nalkanów krótkołańcuchowe, występujące w zakresie od 15 do 23 atomów węgla w cząsteczce. Wartości wskaźnika CPI są generalnie wyższe niż 1, co wskazuje na udział materii organicznej pochodzącej z wosków roślin wyższych. Pod wpływem post-diagenetycznego utleniania zmineralizowanych próbek drewna zmienia się dystrybucja n-alkanów. W badanych próbkach obecne są diaster-13 (17)-enes o 28 i 29 atomów węgla w cząsteczce, natomiast te o 29 atomów znacznie przeważają.

  14. Measurement of Small Values of Hydrostatic Pressure with the Compensation of Atmospheric Pressure Influence / Pomiar Małych Wartości Ciśnienia Hydrostatycznego Z Kompensacją Wpływu Ciśnienia Atmosferycznego

    NASA Astrophysics Data System (ADS)

    Broda, Krzysztof; Filipek, Wiktor

    2013-09-01

    structure has been simplified and the measurement accuracy has increased. Znajomość rozkładu ciśnienia (lub różnicy ciśnień) determinuje opis przepływu płynu przez ośrodek porowaty. W przypadku dużych liczb Reynoldsa nie nastręcza to większych trudności, lecz dla przepływów laminarnych (tj. dla liczb Re (Bear, 1988; Duckworth, 1983; Troskolański, 1957) z zakresu 0.01 do 3) jest to praktycznie niemożliwe w oparciu o dostępne na rynku przyrządy. Przyczyny powodujące taką sytuację zostały omówione w poprzednim opracowaniu (Broda i Filipek, 2012), w którym zwrócono uwagę na trudności pomiarów związane z napięciem powierzchniowym czy włoskowatością (Adamson, 1997). Zaproponowano (Broda i Filipek, 2012) nową, autorską metodę pomiaru bardzo małych różnic ciśnień oraz skonstruowano odpowiednie stanowisko składające się z dwóch oddzielnych zbiorników pomiarowych oraz przeprowadzono pomiary. Z przeprowadzonych badań (Broda i Filipek, 2012) wynikała konieczność zastosowania stabilizacji temperatury urządzenia oraz kompensacji wpływu ciśnienia atmosferycznego na proces pomiarowy. Niniejsza publikacja przedstawia wyniki kontynuacji badań nad metodami i aparaturą do pomiaru bardzo małych różnic ciśnień z uwzględnieniem zdobytych doświadczeń, w oparciu o nowe stanowisko pomiarowe, którego zasadę działania i budowę przedstawiono na rys. 1-5, kolejno przedstawiając koncepcję wykonania pomiaru małych wartości ciśnienia hydrodynamicznego z kompensacją wpływu ciśnienia atmosferycznego rys. 1; ilustrację obrazującą stan odpowiadający przypadkowi braku przepływu płynu przez badany obiekt rys. 2; omawiając stan odpowiadający przypadkowi przepływu płynu przez badany obiekt rys. 3. Kolejno omówiono stan odpowiadający pomiarowi spadku ciśnienia na badanym obiekcie rys. 4 oraz przedstawiono metodykę pomiaru (zależności (1) - (20)). Zdjęcie stanowiska badawczego oraz jego elementów ilustruje rys. 5. W

  15. Evaluation and Management of the Gas and Rock Outburst Hazard in the Light of International Legal Regulations

    NASA Astrophysics Data System (ADS)

    Skoczylas, Norbert; Wierzbicki, Mirosław

    2014-12-01

    ądzanie ryzykiem wyrzutu, ale dają natomiast zarys tego, jakie elementy muszą być uwzględnione w rozwoju zarządzaniu ryzykiem. Kategoryzacja zagrożenia wyrzutowego w krajach europejskich i w Chinach ma wiele cech wspólnych. Ustalane są najczęściej dwie, lub trzy kategorie zagrożenia. Często incydenty wyrzutów, bądź poważnych symptomów mogących świadczyć o zagrożeniu są podstawą do zaliczenia pokładu do najwyższej kategorii zagrożenia. Dominującym parametrem w podstawowej ocenie zagrożenia wyrzutowego jest zawartość metanu w pokładzie węgla. Występuje ona w aktach prawnych wszystkich krajów, które narzucają konkretne sposoby określana stanu zagrożenia, jedynie przepisy chińskie nie obligują do badań zawartości gazu w węglu. W przepisach chińskich pojawia się pomiar ciśnienia gazu.

  16. Stability Assessment of the High Safety Pillars in Slovenian Natural Stone Mines / Ocena Stabilności Wysokich Filarów Bezpieczeństwa W Kopalniach Kamieni Naturalnych W Słowenii

    NASA Astrophysics Data System (ADS)

    Kortnik, Jože

    2015-03-01

    (wapień), w 2008 kamieniołom Lipica I (wapień), w roku 2009 wapień pozyskiwać także zaczęto z kamieniołomu w Dolinie. Działo się to głównie z uwagi na strukturę geologiczną w tych miejscach, warunki geologiczne kamieniołomów, potencjalnie grube warstwy nadkładu w przypadku rozszerzania działalności w części odkrywkowej kamieniołomu, a także rosnący popyt na te surowce (kamień naturalny). Podziemne wydobycie kamieni naturalnych we wszystkich tych lokalizacjach odbywa się za pomocą zmodyfikowanej metody filarowo- komorowej, dostosowanej do uwarunkowań poszczególnych lokalizacji, z wykorzystaniem układu mniej lub bardziej regularnie rozmieszczonych filarów zabezpieczających. Ponieważ podziemne wydobycie naturalnych bloków skalnych odbywa się stosunkowo płytko pod powierzchnią, (na głębokościach rzędu 10-40 m), to wartości pierwotnego naprężenia pionowego są stosunkowo niewielkie (poniżej 1.0 MPa). Wskutek tego powstaje poważne ryzyko odrywania się od stropu bloków skalnych w kształcie klinów, zwłaszcza w dużych, otwartych komorach podziemnych. W latach ubiegłych instalowano układy monitorujące stan naprężeń i odkształceń, wykorzystywane przy planowaniu wymiarów (szerokości i wysokości) dużych, otwartych, przestrzennych komór podziemnych oraz wymiarów filarów zabezpieczających, a także układy zapewniające stałą kontrolę i wykrywanie niestabilności w obrębie stropu oraz w ścianach bocznych komór. Niniejsza praca zawiera przegląd metod i urządzeń wykorzystywanych do optymalizacji i bezpieczeństwa monitorowania stanu filarów zabezpieczających w podziemnych kopalniach kamieni naturalnych w Słowenii.

  17. Sorption of Pb2+ Ions from Aqueous Solutions on Organic Wastes (part i) / Sorpcja JONÓW Pb2+ Z ROZTWORÓW Wodnych NA Odpadach Organicznych (CZĘŚĆ I)

    NASA Astrophysics Data System (ADS)

    Bożęcka, Agnieszka; Sanak-Rydlewska, Stanisława

    2013-12-01

    ępuje stopniowy spadek sorpcji, co prawdopodobnie może być związane z niszczeniem miejsc aktywnych obecnych na powierzchni sorbentu lub przesunięciem równowagi procesu na korzyść desorpcji (rys. 4). Wyniki uzyskane potwierdzają również egzotermiczną naturę badanego procesu sorpcji. Adsorpcję jonów Pb2+ na użytych sorbentach opisano za pomocą modelu Langmuira. Założenia tego modelu podano w rozdziale 4.1. Najlepsze właściwości sorpcyjne w stosunku do jonów Pb2+ wykazałyłuski słonecznika. Maksymalna pojemność sorpcyjna dla tego sorbentu wyniosła 36,9 mg/g (tabela 1, rysunek 5). W przypadku łupin orzecha i pestek śliwek stała qmax izotermy Langmuira przyjmuje wartości równe 23,1 mg/g i 21,2 mg/g.

  18. Mathematical Model of Forecasting the Formation of Sinkhole Using Salustowicz's Theory / Model Matematyczny Prognozowania Zapadlisk Przy Wykorzystaniu Teorii Sklepienia Ciśnień Sałustowicza

    NASA Astrophysics Data System (ADS)

    Strzałkowski, Piotr

    2015-03-01

    órej wykorzystano teorię sklepienia ciśnień (Sałustowicz, 1956). Teoria ta znakomicie nadaje się do tego celu, gdyż jako jedyna z wielu w tym zakresie pozwala określić, czy pustka związana z wyrobiskiem znajduje się w stanie stateczności. Znane są bowiem przypadki, gdy płytkie wyrobiska górnicze, bez obudowy przez wiele lat pozostają w stanie nienaruszonym. W ramach pracy dokonano szczegółowych obliczeń pola strefy odprężonej nad wyrobiskiem, bez stosowania uproszczeń przyjętych przez autora metody. Stosując podobne założenia jak w innych, znanych z literatury rozwiązaniach, podano warunki, mówiące o tym kiedy gruzowisko skalne zapełni szczelnie pustkę, bez powstania pustki wtórnej, a kiedy pustka wtórna powstanie. Zależy to od wymiarów i głębokości lokalizacji pustki oraz własności górotworu nad pustką. Warunkiem wystąpienia zapadliska jest aby strefa odprężona, związana z pustką pierwotną lub wtórną osiągnęła wysokość, przy której obejmować będzie nadkład, zbudowany ze skał luźnych. W dalszej kolejności zaproponowano wzory umożliwiające określenie wymiarów zapadlisk. Wyróżniono przy tym dwa przypadki: • gdy strop pustki osiąga spąg nadkładu - wzór (15), • gdy strefa odprężona obejmuje swym zasięgiem luźne skały nadkładu - wzór (19). Dalszym etapem badań prowadzonych przez autora jest sformułowanie warunków, pozwalających stwierdzić, kiedy eksploatacja górnicza prowadzona pod pustką może wywołać jej samopodsadzenie, a w konsekwencji spowodować powstanie zapadliska na powierzchni. Prowadzone są również prace związane z utworzeniem oprogramowania komputerowego, wykorzystującego podane wzory i z weryfikacją rozwiązania w oparciu o przypadki znane z praktyki górniczej.

  19. Participation of Quaternary Aquifers in Groundwater Inflow to Mines in the Upper Silesian Coal Basin (USCB) / Udział Wodonośnych Utworów Czwartorzędowych W Procesie Zawodnienia Kopalń Górnośląskich

    NASA Astrophysics Data System (ADS)

    Różkowski, Kazimierz; Różkowski, Andrzej; Sołtysiak, Marek

    2015-03-01

    The Upper Silesian Coal Basin (USCB) is situated within Variscean depression in the southern Poland. Mining of the hard coal, ore and sand deposits in the USCB has a long-lasting tradition. Exploitation has been carried out with both - open pit and mainly underground operations. The intensity of water inflows to mines depends on geogenic and technological factors. Among geogenic factors the main one is occurrence of thick water - bearing Quaternary sediments in the roof of Carboniferous ore deposits. Among technological factors the essential influence on the inflows to the mine workings have: time, depth and surface of exploitation, as well as drainage intensity. Górnośląskie Zagłębie Węglowe (GZW) jest niezależnym regionem hydrogeologicznym. W jego zasięgu wydziela się dwa subregiony hydrogeologiczne: północno-wschodni ( I) i południowo-zachodni (II), o odmiennych układach i warunkach hydrogeologicznych. Granicę między subregionami wyznacza zasięg występowania zwartej pokrywy ilastych, izolujących podłoże, utworów miocenu. W zasięgu subregionu I czwartorzędowe poziomy wodonośne znajdują się w więzi hydraulicznej z poziomami wodonośnymi karbonu lub triasu. W subregionie II więź hydrauliczna między karbońskimi i czwartorzędowymi poziomami wodonośnymi występuje tylko w zasięgu erozyjnych okien hydrogeologicznych w utworach miocenu. Na obszarze GZW obserwuje się wyraźne zróżnicowanie miąższości i wykształcenia litologicznego pokrywy utworów czwartorzędowych. Wspomniane utwory są reprezentowane przez piaszczysto-gliniaste osady, których miąższości wahają się w granicach od dziesiętnych metra do ponad 120 m. W zasięgu rejonów górniczych czwartorzędowe poziomy wodonośne są intensywnie drenowane przez wyrobiska górnicze kopalń głębinowych węgla i rud cynkowo-ołowiowych oraz odkrywkowych surowców okruchowych. Eksploatacja górnicza prowadzona jest na skalę przemysłową przez okres

  20. Analytical Model of Water Flow in Coal with Active Matrix

    NASA Astrophysics Data System (ADS)

    Siemek, Jakub; Stopa, Jerzy

    2014-12-01

    systemu szczelin, spękań i ewentualnie największych porów. Przepływowi w systemie szczelin towarzyszyć może wymiana masy z matrycą, której intensywność zależy m.in. od właściwości węgla i warunków panujących w układzie przepływowym. W szczególności matryca węglowa może pochłaniać wodę pod wpływem sił kapilarnych, co wpływa na przepływ w szczelinach. W artykule zostało zaproponowane równanie różniczkowe cząstkowe opisujące nasycenie wodą w systemie szczelin z uwzględnieniem wymiany masy z matrycą pod wpływem sił kapilarnych. Podano dokładne rozwiązanie analityczne, które może być zastosowane w praktyce inżynierskiej. Zauważono, że szybkość wymiany masy między szczelinami i matrycą wyraża się formułą analogiczną do prawa stygnięcia Newtona, ale w analizowanym przypadku współczynnik wymiany masy zależy nie tylko od właściwości węgla i płynów ale również od położenia i czasu. Stały człon tego współczynnika może być obliczony teoretycznie lub wyznaczony eksperymentalnie

  1. Cuttings Transport with Foam in Highly Inclined Wells at Simulated Downhole Conditions / Transport urobku wiertniczego przy użyciu piany w silnie nachylonych otworach w symulowanych warunkach w otworze

    NASA Astrophysics Data System (ADS)

    Xu, Jiafu; Ozbayoglu, Evren; Miska, Stefan Z.; Yu, Mengjiao; Takach, Nicholas

    2013-06-01

    of this paper will help designers with the choice of optimal drilling fluid for drilling horizontal wells in unconventional (shale) gas/oil reservoirs. Równolegle ze stale rosnącym zapotrzebowaniem na prowadzenia prac udostępniających w złożach niekonwencjonalnych notuje się wzrost świadomości społecznej odnośnie zagadnień ochrony środowiska. Piana jako alternatywa dla tradycyjnej płuczki wiertniczej nabiera coraz większego znaczenia w górnictwie otworowym. Wiercenie przy użyciu piany pomogą ograniczać zniszczenia formacji geologicznych, redukuje zużycie wody, pozwala na zminimalizowanie oporów ruchu i momentów obrotowych silników. Ponadto, koszty piany są niższe a jej oddziaływanie na środowisko naturalne jest mniej znaczne niż w przypadku typowych płuczek opartych na olejach syntetycznych używanych w trakcie udostępniania trudnych w eksploatacji złóż, np. gazu łupkowego. Wiercenia odcinków poziomych lub prawie poziomych są już szeroko stosowane a zapotrzebowanie na takie odcinki wrasta, ważnym jest właściwe rozpoznanie problemów związanych z transportem urobku wiertniczego i czyszczeniem otworu w trakcie prowadzenia prac wiertniczych na tych odcinkach przy użyciu piany. Zespól badaczy z uniwersytetu w Tulsa zaangażowanych w projekt badawczy w dziedzinie wiertnictwa (TUDRP) przeprowadził serię eksperymentów mających na celu zbadanie wpływu zmiany kąta nachylenia otworu z 90 na 70 stopni na przebieg transportu urobku wiertniczego z wykorzystanie piany w warunkach podwyższonego ciśnienia i podwyższonych temperatur. Badania eksperymentalne i teoretyczne obejmowały także analizę pozostałych parametrów procesu: jakość piany, natężenie przepływu piany, stężenie polimerów, prędkość obrotowa przewodu wiertniczego. Nie stwierdzono znacznych różnic w stężeniu zwiercin ani utraty ciśnienia wskutek tarcia w trakcie zmiany kąta nachylenia z 90 na 70 stopni. Ponadto, dodatkowy wzrost prędkości ruchu

  2. Analytical Design of Water-Free Production in Horizontal Wells Using Hodograph Method / Zastosowanie metody hodografu do określenia krytycznego wydatku poziomych otworów produkcyjnych

    NASA Astrophysics Data System (ADS)

    Qin, Wenting; Wojtanowicz, Andrew K.; White, Christopher D.

    2013-06-01

    żków wodnych prowadzących do zawodnienia otworu. Jednakże duża powierzchnia kontaktu ze złożem staje się wadą otworów poziomych gdy stożek wodny dostanie się do otworu. Następuje wtedy gwałtowne zawodnienie otworu i szybka utrata produktywności. Z tego powodu wydatek otworu musi być utrzymany poniżej wartości wydatku krytycznego, tzn. maksymalnego wydatku bez udziału stożka wodnego. Istniejące modele analityczne wydatku krytycznego są albo zbyt uproszczone lub też niedokładne w opisie lokalnej powierzchni kontaktu między ropą naftową i wodą podścielającą co prowadzi do błędnej oceny wydatku krytycznego. W tym artykule prezentujemy nowy model matematyczny wydatku krytycznego który jest bardziej dokładny przez co lepiej nadaje się do obliczeń projektowych. W przeciwieństwie do istniejących modeli, nasz model uwzględnia ograniczenie dopływu ropy do otworu spowodowane wzrostem stożka wodnego ponad statyczną powierzchnię kontaktu ropy z wodą podścielającą oraz pozwala dokładnie obliczyć wydatek krytyczny oraz opisać kształt powierzchni stożka i zmianę ciśnienia w złożu z odległością od otworu poziomego. Równania modelu zostały wyprowadzone z teorii hodografu połączonej z metodą odwzorowań konforemnych. Wyniki obliczeń przy użyciu równań modelu wykazują zgodność z wynikami symulatora złoża. Stwierdzono również, że typowe dla innych modeli założenie płaskiej powierzchni kontaktu ropa/woda i zaniedbanie efektu kształtu stożka wodnego może prowdzić do 50-procentowej przeceny wartości wydatku krytycznego

  3. Underground Tourist Routes in the Context of Sustainable Development / Podziemne Trasy Turystyczne W Procesie Zrównoważonego Rozwoju

    NASA Astrophysics Data System (ADS)

    Wieja, Tomasz; Chmura, Janusz; Bartos, Maciej

    2015-09-01

    residence patterns that have emerged over centuries. Well - preserved and protected excavations are the relics of the past, are part of the cultural heritage and become a rich source of knowledge about history. Ostanie lata przyniosły rozwój skoncentrowany na maksymalizacji zysków ekonomicznych i politycznych. Doprowadził on do kryzysów środowiskowych, społecznych, a nawet gospodarczych. Przyczyniło się to do powstania koncepcji zrównoważonego rozwoju. Jest to dążenie do poprawy jakości życia przy zachowaniu równości społecznej, bioróżnorodności i bogactwa zasobów naturalnych. Bardziej świadome i aktywne społeczeństwo ma do odegrania kluczową rolę w zrównoważonym rozwoju. Z jednej strony jest regulatorem wpływu gospodarki na środowisko, zaś z drugiej kapitał społeczny zapewnia ciągłość wizji rozwoju i planowania jej realizacji. Ochrona zabytkowych podziemi bardzo dobrze wpisuje sie w proces zrównoważonego rozwoju. Zachowane i udostępnione zabytkowe podziemia są częścią dziedzictwa kulturowego i mają za zadanie zachowania wartości historycznych, kulturowych, przyrodniczych, a także użytkowych. W ostatnich latach obserwuje się intensywny rozwój działań zmierzających do wykorzystania zabytkowych podziemi do celów użytkowych. Problem rewitalizacji zabytkowych podziemi, a więc przywracanie "do życia" starych wyrobisk, jest bardzo skomplikowanym procesem przywracania pierwotnych funkcji nieczynnym lub zdegradowanym obiektom podziemnym. W procesie projektowania bardzo ważne są działania zgodnie z procesami naturalnymi obowiązującymi w przyrodzie. Zabezpieczane i adaptowane podziemia muszą w rezultacie działań człowieka być "przyjazne" i akceptowane przez użytkowników, będąc elementem ochrony dziedzictwa kulturowego człowieka, a więc częścią składową zrównoważonego rozwoju. Problemy techniczne występujące przy adaptacji zabytkowych podziemi są nie tylko praktycznym zastosowaniem nauki, ale tak

  4. Investigating the Molecular Mechanism of TSO1 Function in Arabidopsis cell division and meristem development

    SciTech Connect

    Zhongchi Liu

    2004-10-01

    Unlike animals, plants are constantly exposed to environmental mutagens including ultraviolet light and reactive oxygen species. Further, plant cells are totipotent with highly plastic developmental programs. An understanding of molecular mechanisms underlying the ability of plants to monitor and repair its DNA and to eliminate damaged cells are of great importance. Previously we have identified two genes, TSO1 and TSO2, from a flowering plant Arabidopsis thaliana. Mutations in these two genes cause callus-like flowers, fasciated shoot apical meristems, and abnormal cell division, indicating that TSO1 and TSO2 may encode important cell cycle regulators. Previous funding from DOE led to the molecular cloning of TSO1, which was shown to encode a novel nuclear protein with two CXC domains suspected to bind DNA. This DOE grant has allowed us to characterize and isolate TSO2 that encodes the small subunit of the ribonucleotide reductase (RNR). RNR comprises two large subunits (R1) an d two small subunits (R2), catalyzes a rate-limiting step in the production of deoxyribonucleotides needed for DNA replication and repair. Previous studies in yeast and mammals indicated that defective RNR often led to cell cycle arrest, growth retardation and p53-dependent apoptosis while abnormally elevated RNR activities led to higher mutation rates. Subsequently, we identified two additional R2 genes, R2A and R2B in the Arabidopsis genome. Using reverse genetics, mutations in R2A and R2B were isolated, and double and triple mutants among the three R2 genes (TSO2, R2A and R2B) were constructed and analyzed. We showed that Arabidopsis tso2 mutants, with reduced dNTP levels, were more sensitive to UV-C. While r2a or r2b single mutants did not exhibit any phenotypes, tso2 r2b double mutants were embryonic lethal and tso2 r2a double mutants were seedling lethal indicating redundant functions among the three R2 genes. Furthermore, tso2 r2a double mutants exhibited increased DNA dam age

  5. Near ultraviolet radiation (280-400 nm): Direct and indirect effects on microbial pathogens

    SciTech Connect

    Asthana, A.

    1993-01-01

    Responses of pigmented pathogenic fungi and E. coli strains differing in DNA repair and catalase proficiency to direct and indirect effects of ultraviolet radiation were evaluated. Pigments in the four fungal pathogens of Citrus differed in their ability to protect against direct UV and damage by UV-A -mediated phototoxins of both host and non-host origin. UV-A and UV-B did not inactivate the fungal species. Differential protection in wild type strains of the two Fusarium spp. and in the wild type strains of the two Penicilium spp. against UV-C was observed. Wild type and mutants with altered coloration in Penicilium spp. protected to varying extent against both [alpha]-T and 8-MOP in the presence of UV-A. UV-B irradiation of E. coli resulted in inactivation of strains deficient in DNA excision repair. Plasmid DNA damaged in vitro by UV-B from lamp systems as well as by sunlight, and transformed in vivo into bacterial cells lacking specific nucleases showed reduced transformation in DNA excision repair strains. UV-B enriched wavelengths isolated from a solar simulator affected plasmid DNA in a similar manner as UV-B from lamp systems. Sunlight, however affected the membrane of whole cells. Concentration of foliar furanocoumarins of Citrus jambhiri decreased with UV-B irradiation. Phototoxicity to Fusarium spp. was accounted for, in part, by furanocoumarins, psoralen and bergapten (5-MOP) and others. Pure psoralen and 5-MOP affected both Fusarium spp. similarly and carotenoids protected only partially in the wild type strains. Citrus targetted the cell membrane in Fusarium spp.l and in E. coli strains; carotenoids in both of which protected against such damage. Loss in structural integrity of plasmid DNA when treated with citral and UV-A correlated with loss in transforming activity. Biological damage to membrane and DNA was due to the production of hydrogen peroxide. Fruit-rot pathogens Penicilium spp. were not affected by either furanocoumarins or citrals.

  6. Pasteurization Procedures for Donor Human Milk Affect Body Growth, Intestinal Structure, and Resistance against Bacterial Infections in Preterm Pigs.

    PubMed

    Li, Yanqi; Nguyen, Duc Ninh; de Waard, Marita; Christensen, Lars; Zhou, Ping; Jiang, Pingping; Sun, Jing; Bojesen, Anders Miki; Lauridsen, Charlotte; Lykkesfeldt, Jens; Dalsgaard, Trine Kastrup; Bering, Stine Brandt; Sangild, Per Torp

    2017-03-15

    Background: Holder pasteurization (HP) destroys multiple bioactive factors in donor human milk (DM), and UV-C irradiation (UVC) is potentially a gentler method for pasteurizing DM for preterm infants.Objective: We investigated whether UVC-treated DM improves gut maturation and resistance toward bacterial infections relative to HP-treated DM.Methods: Bacteria, selected bioactive components, and markers of antioxidant capacity were measured in unpasteurized donor milk (UP), HP-treated milk, and UVC-treated milk (all from the same DM pool). Fifty-seven cesarean-delivered preterm pigs (91% gestation; ratio of males to females, 30:27) received decreasing volumes of parental nutrition (average 69 mL ⋅ kg(-1) ⋅ d(-1)) and increasing volumes of the 3 DM diets (n = 19 each, average 89 mL ⋅ kg(-1) ⋅ d(-1)) for 8-9 d. Body growth, gut structure and function, and systemic bacterial infection were evaluated.Results: A high bacterial load in the UP (6×10(5) colony forming units/mL) was eliminated similarly by HP and UVC treatments. Relative to HP-treated milk, both UVC-treated milk and UP showed greater activities of lipase and alkaline phosphatase and concentrations of lactoferrin, secretory immunoglobulin A, xanthine dehydrogenase, and some antioxidant markers (all P < 0.05). The pigs fed UVC-treated milk and pigs fed UP showed higher relative weight gain than pigs fed HP-treated milk (5.4% and 3.5%), and fewer pigs fed UVC-treated milk had positive bacterial cultures in the bone marrow (28%) than pigs fed HP-treated milk (68%) (P < 0.05). Intestinal health was also improved in pigs fed UVC-treated milk compared with those fed HP-treated milk as indicated by a higher plasma citrulline concentration (36%) and villus height (38%) (P < 0.05) and a tendency for higher aminopeptidase N (48%) and claudin-4 (26%) concentrations in the distal intestine (P < 0.08). The gut microbiota composition was similar among groups except for greater proportions of Enterococcus in pigs

  7. Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling

    NASA Technical Reports Server (NTRS)

    Grace, Joseph M.; Verseux, Cyprien; Gentry, Diana; Moffet, Amy; Thayabaran, Ramanen; Wong, Nathan; Rothschild, Lynn

    2013-01-01

    number or growth rate of surviving cells. We are on our second prototype iteration, with demonstrated functions of microbial growth monitoring and dynamic exposure to UV-C radiation and temperature. We plan to add functionality for general chemical presence or absence by Nov. 2013. By making the project low-cost and open-source, we hope to encourage others to use it as a basis for future development of a common microbial environmental adaptation testbed.

  8. Impact of solar versus volcanic activity variations on tropospheric temperatures and precipitation during the Dalton Minimum

    NASA Astrophysics Data System (ADS)

    Anet, J. G.; Muthers, S.; Rozanov, E. V.; Raible, C. C.; Stenke, A.; Shapiro, A. I.; Brönnimann, S.; Arfeuille, F.; Brugnara, Y.; Beer, J.; Steinhilber, F.; Schmutz, W.; Peter, T.

    2014-05-01

    The aim of this work is to elucidate the impact of changes in solar irradiance and energetic particles versus volcanic eruptions on tropospheric global climate during the Dalton Minimum (DM, AD 1780-1840). Separate variations in the (i) solar irradiance in the UV-C with wavelengths λ < 250 nm, (ii) irradiance at wavelengths λ > 250 nm, (iii) in energetic particle spectrum, and (iv) volcanic aerosol forcing were analyzed separately, and (v) in combination, by means of small ensemble calculations using a coupled atmosphere-ocean chemistry-climate model. Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decreased global mean temperature by up to 0.5 K for 2-3 years after the eruption. However, while the volcanic effect is clearly discernible in the Southern Hemispheric mean temperature, it is less significant in the Northern Hemisphere, partly because the two largest volcanic eruptions occurred in the SH tropics and during seasons when the aerosols were mainly transported southward, partly because of the higher northern internal variability. In the simulation including all forcings, temperatures are in reasonable agreement with the tree ring-based temperature anomalies of the Northern Hemisphere. Interestingly, the model suggests that solar irradiance changes at λ < 250 nm and in energetic particle spectra have only an insignificant impact on the climate during the Dalton Minimum. This downscales the importance of top-down processes (stemming from changes at λ < 250 nm) relative to bottom-up processes (from λ > 250 nm). Reduction of irradiance at λ > 250 nm leads to a significant (up to 2%) decrease in the ocean heat content (OHC) between 0 and 300 m in depth, whereas the changes in irradiance at λ < 250 nm or in energetic particles have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing

  9. Impact of solar vs. volcanic activity variations on tropospheric temperatures and precipitation during the Dalton Minimum

    NASA Astrophysics Data System (ADS)

    Anet, J. G.; Muthers, S.; Rozanov, E. V.; Raible, C. C.; Stenke, A.; Shapiro, A. I.; Brönnimann, S.; Arfeuille, F.; Brugnara, Y.; Beer, J.; Steinhilber, F.; Schmutz, W.; Peter, T.

    2013-11-01

    The aim of this work is to elucidate the impact of changes in solar irradiance and energetic particles vs. volcanic eruptions on tropospheric global climate during the Dalton Minimum (DM, 1780-1840 AD). Separate variations in the (i) solar irradiance in the UV-C with wavelengths λ < 250 nm, (ii) irradiance at wavelengths λ > 250 nm, (iii) in energetic particle spectrum, and (iv) volcanic aerosol forcing were analyzed separately, and (v) in combination, by means of small ensemble calculations using a coupled atmosphere-ocean chemistry-climate-model. Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decrease global mean temperature by up to 0.5 K for 2-3 yr after the eruption. However, while the volcanic effect is clearly discernible in the southern hemispheric mean temperature, it is less significant in the Northern Hemisphere, partly because the two largest volcanic eruptions occurred in the SH tropics and during seasons when the aerosols were mainly transported southward, partly because of the higher northern internal variability. In the simulation including all forcings, temperatures are in reasonable agreement with the tree-ring-based temperature anomalies of the Northern Hemisphere. Interestingly, the model suggests that solar irradiance changes at λ < 250 nm and in energetic particle spectra have only insignificant impact on the climate during the Dalton Minimum. This downscales the importance of top-down processes (stemming from changes at λ < 250 nm) relative to bottom-up processes (from λ > 250 nm). Reduction of irradiance at λ > 250 nm leads to a significant (up to 2%) decrease of the ocean heat content (OHC) between the 0 and 300 m of depth, whereas the changes in irradiance at λ < 250 nm or in energetic particle have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing the OHC

  10. The effects of space travel to Deinococcus radiodurans and the carotenoid Deinoxanthin

    NASA Astrophysics Data System (ADS)

    Rettberg, Petra; De Vera, Jean-Pierre; Bohmeier, Maria; Leuko, Stefan; Boettger, Ute; Hanke, Franziska

    . Investigating the samples with Raman (Laser 532 nm, 3 mW) revealed that Deinoxanthin is still detectable in its origin configuration even after exposure to 10.000 J/m (2) UV-C radiation. Similar results were observed with the crude cell extract from D. radiodurans. Taken these results into account, the carotenoid Deinoxanthin may serve as a robust biomarker to detect traces of life and Raman spectroscopy is the ideal method to detect the biomarker on a foreign planet. References: Winter, Y.D. et al. (2013) Astrobiology 13:1065-1080.

  11. Activation of c-Jun N-Terminal Kinase 1 by UV Irradiation Is Inhibited by Wortmannin without Affecting c-jun Expression

    PubMed Central

    Fritz, G.; Kaina, B.

    1999-01-01

    Activation of c-Jun N-terminal kinases (JNKs)/stress-activated protein kinases is an early response of cells upon exposure to DNA-damaging agents. JNK-mediated phosphorylation of c-Jun is currently understood to stimulate the transactivating potency of AP-1 (e.g., c-Jun/c-Fos; c-Jun/ATF-2), thereby increasing the expression of AP-1 target genes. Here we show that stimulation of JNK1 activity is not a general early response of cells exposed to genotoxic agents. Treatment of NIH 3T3 cells with UV light (UV-C) as well as with methyl methanesulfonate (MMS) caused activation of JNK1 and an increase in c-Jun protein and AP-1 binding activity, whereas antineoplastic drugs such as mafosfamide, mitomycin C, N-hydroxyethyl-N-chloroethylnitrosourea, and treosulfan did not elicit this response. The phosphatidylinositol 3-kinase inhibitor wortmannin specifically blocked the UV-stimulated activation of JNK1 but did not affect UV-driven activation of extracellular regulated kinase 2 (ERK2). To investigate the significance of JNK1 for transactivation of c-jun, we analyzed the effect of UV irradiation on c-jun expression under conditions of wortmannin-mediated inhibition of UV-induced stimulation of JNK1. Neither the UV-induced increase in c-jun mRNA, c-Jun protein, and AP-1 binding nor the activation of the collagenase and c-jun promoters was affected by wortmannin. In contrast, the mitogen-activated protein kinase/ERK kinase inhibitor PD98056, which blocked ERK2 but not JNK1 activation by UV irradiation, impaired UV-driven c-Jun protein induction and AP-1 binding. Based on the data, we suggest that JNK1 stimulation is not essential for transactivation of c-jun after UV exposure, whereas activation of ERK2 is required for UV-induced signaling leading to elevated c-jun expression. PMID:10022864

  12. Perchlorate production by photodecomposition of aqueous chlorine solutions.

    PubMed

    Rao, Balaji; Estrada, Nubia; McGee, Shelly; Mangold, Jerry; Gu, Baohua; Jackson, W Andrew

    2012-11-06

    Aqueous chlorine solutions (defined as chlorine solutions (Cl(2,T)) containing solely or a combination of molecular chlorine (Cl(2)), hypochlorous acid (HOCl), and hypochlorite (OCl(-))) are known to produce toxic inorganic disinfection byproduct (e.g., chlorate and chlorite) through photoactivated transformations. Recent reports of perchlorate (ClO(4)(-)) production-a well-known thyroid hormone disruptor- from stored bleach solutions indicates the presence of unexplored transformation pathway(s). The evaluation of this potential ClO(4)(-) source is important given the widespread use of aqueous chlorine as a disinfectant. In this study, we perform detailed rate analysis of ClO(4)(-) generation from aqueous chlorine under varying environmental conditions including ultraviolet (UV) light sources, intensity, solution pH, and Cl(2,T) concentrations. Our results show that ClO(4)(-) is produced upon UV exposure of aqueous chlorine solutions with yields ranging from 0.09 × 10(-3) to 9.2 × 10(-3)% for all experimental conditions. The amount of ClO(4)(-) produced depends on the starting concentrations of Cl(2,T) and ClO(3)(-), UV source wavelength, and solution pH, but it is independent of light intensity. We hypothesize a mechanistic pathway derived from known reactions of Cl(2,T) photodecomposition that involves the reaction of Cl radicals with ClO(3)(-) to produce ClO(4)(-) with calculated rate coefficient (k(ClO4-)) of (4-40) × 10(5) M(-1) s(-1) and (3-250) × 10(5) M(-1) s(-1) for UV-B/C and UV-A, respectively. The measured ClO(4)(-) concentrations for both UV-B and UV-C experiments agreed well with our model (R(2) = 0.88-0.99), except under UV-A light exposure (R(2) = 0.52-0.93), suggesting the possible involvement of additional pathways at higher wavelengths. Based on our results, phototransformation of aqueous chlorine solutions at concentrations relevant to drinking water treatment would result in ClO(4)(-) concentrations (~0.1 μg L(-1)) much below the proposed

  13. Influence of UV lamp, sulfur(IV) concentration, and pH on bromate degradation in UV/sulfite systems: Mechanisms and applications.

    PubMed

    Xiao, Qian; Wang, Ting; Yu, Shuili; Yi, Peng; Li, Lei

    2017-03-15

    Bromate (BrO3(-)) is a possible human carcinogen regulated worldwide at a strict standard of 10 μg/L in drinking water. Removal of BrO3(-) by advanced reduction processes (ARPs) has attracted much attention due to its high reduction efficiency and easier combination with ultraviolet (UV) disinfection. In this study, we employed a UV/sulfite process to degrade BrO3(-) and studied the effects of UV lamp, sulfur(IV) concentration, and pH on effectiveness of the system in degrading BrO3(-). Low-pressure UV lamps (UV-L) instead of medium-pressure UV lamps (UV-M) were selected because of the high ultraviolet-C (UV-C) efficiency of UV-L. The increased sulfur(IV) concentration is proportionally correlated with enhanced degradation kinetics. BrO3(-) reduction was improved by increasing pH when pH is within 6.0-9.0, and principal component analysis demonstrated that pH is the most influential factor over sulfur(IV) concentration and type of UV lamp. Degradation mechanisms at different pH levels were subsequently investigated. Results showed that the reduction reactions are induced by hydrated electron (eaq(-)) at pH > 9.0, by H at pH 4.0, and by both eaq(-) and H at pH 7.0. Effective quantum efficiency for the formation of eaq(-) and H in the photocatalytic systems was determined to be 0.109 ± 0.001 and 0.034 ± 0.001 mol E(-1), respectively. Furthermore, mass balance calculation of bromine and sulfur at pH 7 showed that bromide, sulfate and possibly dithionate ions were the major products, and a degradation pathway was proposed accordingly. Moreover, UV/sulfite processes could reduce the initial bromate concentration of 0.1 mM by 82% and 95% in the presence and absence of O2 in tap water respectively, and 99% in the absence of O2 in deionized water within 20 min at pH 9.0 and 2.0 mM sulfur (IV).

  14. SPICAM-light on Mars-Express as a monitor of surface UV radiation and atmospheric oxidants

    NASA Astrophysics Data System (ADS)

    Muller, C.; Moreau, D.; Fonteyn, D.; Bertaux, J. L.; Korablev, O.

    2001-02-01

    The SPICAM-light optical package on the ESA Mars-Express mission includes a UV radiation channel to perform nadir and limb observation between 118 and 320 nm as well as an infrared channel extending between 1 and 1.7 μm. The UV resolution will be 0.5 nm per pixel. This spectral range was chosen for the observation of the total column and vertical distribution of ozone, aerosols and other gases; it is also aimed at the Martian upper atmosphere where the obtained data will help to constrain the escape problem. The associated infrared channel specialises in water vapour. The UV range corresponds exactly to the UV-B and UV-C spectral domains and will be used to determine the solar mid-UV radiation received at the surface and to establish its climatology. Signal simulations are performed using the results of a 2-D Martian model as input (Moreau, Thesis, Université Libre de Bruxelles, Brussels, Belgium 1995; Moreau, Fonteyn, Two-dimensional study of the atmospheric and surface oxidants on Mars, Proceedings of the Fifth International Conference on Mars, Lunar and Planetary Institute Contribution, Vol. 972, 1999, p. 6093) in order to show the influence of ozone and aerosol distributions on this radiation. Possibility of a UV shield exists during extreme polar ozone maxima as well as during dust storms, due to the UV absorption of Martian dust. In the other more normal cases, the daytime mid-UV radiation between 200 and 320 nm penetrates in sufficient amount to prevent the development of surface micro-organisms. Other life science conclusions could be drawn from the SPICAM-light observations: the direct mapping of water vapour will constrain the possible occurrences of subsurface liquid water that could be a favourable environment for the survival of life. SPICAM-light by its mapping of ozone and water vapour will also allow determining the amount of oxidants and especially OH. These could also affect the survival of Martian or contaminating bacteria. It is also intended

  15. Self-cleaning properties, mechanical stability, and adhesion strength of transparent photocatalytic TiO(2)-ZnO coatings on polycarbonate.

    PubMed

    Fateh, Razan; Dillert, Ralf; Bahnemann, Detlef

    2014-02-26

    Transparent layers containing TiO2 have been intensively studied because of their interesting application potential including photocatalytically active and self-cleaning surfaces. In the present work, transparent TiO2-ZnO thin films on a SiO2 interlayer were successfully deposited on the surface of polycarbonate to provide polymeric sheets with a self-cleaning, superhydrophilic, and photocatalytically active surface layer. To ensure a good adhesion of the SiO2 interlayer, the polycarbonate sheets were first modified by irradiation with UV(C) light. The prepared films were characterized by UV/vis spectrophotometry, SEM, XRD, Raman spectroscopy, ellipsometry, and water contact-angle measurements. All prepared films are transparent, have thicknesses in the range between 120 and 250 nm, and possess superhydrophilic properties. Moreover, they exhibit good adhesion qualities as defined quantitatively by cross-cut tests. However, their mechanical strengths, checked by felt-abrasion tests, differ by changing the molar TiO2-ZnO ratio. The photocatalytic activity, expressed as photonic efficiency, of the coated surfaces was estimated from the kinetics of the photocatalytic degradation of methylene blue and methyl stearate. The combination between superhydrophilic properties and photocatalytic activity was determined by studying the change of water contact angle during the storage of the prepared films in the dark under an ambient atmosphere and under an atmosphere containing either acetone or isopropanol followed by UV(A) irradiation. In addition, self-cleaning properties were examined by determining the changes in the contact angle during the irradiation time after applying oleic acid to the surface. The results show that increasing the molar ratio of ZnO in TiO2 coatings up to 5% yields maximum photonic efficiency values of 0.023%, as assessed by the photocatalytic degradation of methylene blue. Moreover, the superhydrophilic coating with a molar TiO2-ZnO ratio of 1

  16. Construction of Bacillus thuringiensis simulant strains suitable for environmental release.

    PubMed

    Park, Sangjin; Kim, Changhwan; Lee, Daesang; Song, Dong Hyun; Cheon, Ki Cheol; Lee, Hong Suk; Kim, Seong Joo; Kim, Jee Cheon; Lee, Sang Yup

    2017-03-03

    For a surrogate bacterium to be used in outdoor studies, it is important to consider environmental and human safety, and ease of detection. Recently, Bacillus thuringiensis, a popular bioinsecticide bacterium, is gaining attention as a surrogate bacterium for its use in biodefense. In this study, we constructed simulant strains of B. thuringiensis with enhanced characteristics for environmental studies. Through transposon mutagenesis, pigment genes were inserted into the chromosome, producing yellow-colored colonies for easy detection. To prevent persistence of spores in the environment, a genetic circuit was designed to produce "a spore without sporulation capability". Two loxP sites were inserted at both ends of the spo0A gene encoding a sporulation master regulator, and a sporulation-dependent Cre expression cassette was inserted into the chromosome. This genetic circuit successfully deleted spo0A during sporulation, producing spores that lacked the spo0A gene. In addition, two major α/β-type small acid-soluble spore protein (SASP) genes, predicted by synteny analysis, were deleted. The spores of the mutant strain showed increased ultraviolet C (UV-C) sensitivity and quickly lost viability when tested in a solar simulator. When the spores of the mutant strain were administered to the lungs of Balb/c mice, cells were quickly removed from the body, suggesting enhanced in vivo safety. All strains constructed in this study contain no antibiotic resistance markers and all heterologous genes were inserted into the chromosome, which are useful features for simulants to be released into the environment.IMPORTANCEB. thuringiensis has recently been receiving increasing attention as a good spore simulant in biodefense research. However, few studies were done to properly address many important features of B. thuringiensis as a simulant in environmental studies. Since spores can persist in the environment for years after release, environmental contamination is a big

  17. Naturally occurring and stress induced tubular structures from mammalian cells, a survival mechanism

    PubMed Central

    Wu, Yonnie; Laughlin, Richard C; Henry, David C; Krueger, Darryl E; Hudson, JoAn S; Kuan, Cheng-Yi; He, Jian; Reppert, Jason; Tomkins, Jeffrey P

    2007-01-01

    Background Tubular shaped mammalian cells in response to dehydration have not been previously reported. This may be due to the invisibility of these cells in aqueous solution, and because sugars and salts added to the cell culture for manipulation of the osmotic conditions inhibit transformation of normal cells into tubular shaped structures. Results We report the transformation of normal spherical mammalian cells into tubular shaped structures in response to stress. We have termed these transformed structures 'straw cells' which we have associated with a variety of human tissue types, including fresh, post mortem and frozen lung, liver, skin, and heart. We have also documented the presence of straw cells in bovine brain and prostate tissues of mice. The number of straw cells in heart, lung tissues, and collapsed straw cells in urine increases with the age of the mammal. Straw cells were also reproduced in vitro from human cancer cells (THP1, CACO2, and MCF7) and mouse stem cells (D1 and adipose D1) by dehydrating cultured cells. The tubular center of the straw cells is much smaller than the original cell; houses condensed organelles and have filamentous extensions that are covered with microscopic hair-like structures and circular openings. When rehydrated, the filaments uptake water rapidly. The straw cell walls, have a range of 120 nm to 200 nm and are composed of sulfated-glucose polymers and glycosylated acidic proteins. The transformation from normal cell to straw cells takes 5 to 8 hr in open-air. This process is characterized by an increase in metabolic activity. When rehydrated, the straw cells regain their normal spherical shape and begin to divide in 10 to 15 days. Like various types of microbial spores, straw cells are resistant to harsh environmental conditions such as UV-C radiation. Conclusion Straw cells are specialized cellular structures and not artifacts from spontaneous polymerization, which are generated in response to stress conditions, like

  18. Mutagenesis by outer space parameters other than cosmic rays

    NASA Astrophysics Data System (ADS)

    Horneck, Gerda; Rabbow, Elke

    We have studied the ability of microorganisms to cope with the complex interplay of the parameters of space in experiments in low Earth orbit and using space simulation facilities on ground. Emphasis was laid on space parameters other than cosmic rays. The studies are directed towards understanding prebiotic chemical evolution and biological evolution processes, and interplanetary transfer of life. Effects of space vacuum: Space experiments have shown that up to 70% of bacterial and fungal spores survived short-term exposure to space vacuum. The chances of survival in space were increased when spores were embedded in chemical protectants such as sugars, or salt crystals, or when they were exposed in multilayer. During the six years lasting LDEF mission up to 80% of bacterial spores survived exposure to space vacuum. A 10-fold increased mutation rate over the spontaneous rate has been observed in spores of Bacillus subtilis after exposure to space vacuum, which is probably based on a unique molecular signature of tandem-double base change at restricted sites in the DNA. In addition, DNA strand breaks have been observed to be induced by vacuum treatment. Effects of extraterrestrial solar UV radiation: Solar UV radiation has been found to be the most deleterious factor of space. The reason for this is the highly energetic UV-C and vacuum UV radiation that is directly absorbed by the DNA and which induces specific photoproducts in the DNA that are highly mutagenic and lethal. The damaging effect of extraterrestrial solar UV radiation was even aggravated, when the spores were simultaneously exposed to both, solar UV radiation and space vacuum. In order to investigate the mutagenic potential of solar UV radiation, DNA of the Escherichia coli plasmid pUC19 was exposed to selected wavebands of UV radiation (from vacuum UV to UV-A) by use of a solar simulator and space simulation facilities. Action spectra revealed that for vacuum UV different kinds of photochemical damage

  19. Life in Ice: Implications to Astrobiology

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.

    2009-01-01

    possible natural phenomenon of the solar system that may have played a profoundly important role in the Origin of Life on Earth and the Distribution of Life in the Cosmos. The paper concludes with a consideration of the protective properties of ice by absorption of UV-B, UV-C, h-rays, gamma-rays and the high energy proton environment of the Jupiter Radiation Belt. A proposed instrument that may provide additional data on the potential survivability of microbial extremophiles encased in ice and subjected to the simulated space environment will be briefly described.

  20. Intense light pulses decontamination of minimally processed vegetables and their shelf-life.

    PubMed

    Gómez-López, V M; Devlieghere, F; Bonduelle, V; Debevere, J

    2005-08-15

    Intense light pulses (ILP) is a new method intended for decontamination of food surfaces by killing microorganisms using short time high frequency pulses of an intense broad spectrum, rich in UV-C light. This work studied in a first step the effect of food components on the killing efficiency of ILP. In a second step, the decontamination of eight minimally processed (MP) vegetables by ILP was evaluated, and thirdly, the effect of this treatment on the shelf-life of MP cabbage and lettuce stored at 7 degrees C in equilibrium modified atmosphere packages was assessed by monitoring headspace gas concentrations, microbial populations and sensory attributes. Proteins and oil decreased the decontamination effect of ILP, whilst carbohydrates and water showed variable results depending on the microorganism. For this reason, high protein and fat containing food products have little potential to be efficiently treated by ILP. Vegetables, on the other hand, do not contain high concentrations of both compounds and could therefore be suitable for ILP treatment. For the eight tested MP vegetables, log reductions up to 2.04 were achieved on aerobic mesophilic counts. For the shelf-life studies, respiration rates at 3% O2 and 7 degrees C were 14.63, 17.89, 9.17 and 16.83 ml O2/h kg produce for control and treated cabbage, and control and treated lettuce respectively; used packaging configurations prevented anoxic conditions during the storage times. Log reductions of 0.54 and 0.46 for aerobic psychrothrophic count (APC) were achieved after flashing MP cabbage and lettuce respectively. APC of treated cabbage became equal than that from control at day 2, and higher at day 7, when the tolerance limit (8 log) was reached and the panel detected the presence of unacceptable levels of off-odours. Control never reached 8 log in APC and were sensory acceptable until the end of the experiment (9 days). In MP lettuce, APC of controls reached rejectable levels at day 2, whilst that of treated

  1. Migration of polycyclic aromatic hydrocarbons (PAHs) in urban treatment sludge to the air during PAH removal applications.

    PubMed

    Karaca, Gizem; Cindoruk, S Siddik; Tasdemir, Yücel

    2014-05-01

    In the present study, the amounts of polycylic aromatic hydrocarbons (PAHs) penetrating into air during PAH removal applications from the urban treatment sludge were investigated. The effects of the temperature, photocatalyst type, and dose on the PAH removal efficiencies and PAH evaporation were explained. The sludge samples were taken from an urban wastewater treatment plant located in the city of Bursa, with 585,000 equivalent population. The ultraviolet C (UV-C) light of 254 nm wavelength was used within the UV applications performed on a specially designed setup. Internal air of the setup was vacuumed through polyurethane foam (PUF) columns in order to collect the evaporated PAHs from the sludge during the PAH removal applications. All experiments were performed with three repetitions. The PAH concentrations were measured by gas chromatography-mass spectrometry (GC-MS). It was observed that the amounts of PAHs penetrating into the air were increased with increase of temperature, and more than 80% of PAHs migrated to the air consisted of 3-ring compounds during the UV and UV-diethylamine (DEA) experiments at 38 and 53 degrees C. It was determined that 40% decrease was ensured in sigma12 (total of 12) PAH amounts with UV application and 13% of PAHs in sludge penetrated into the air. In the UV-TiO2 applications, a maximum 80% of sigma12 PAH removal was obtained by adding 0.5% TiO2 of dry weight of sludge. The quantity of PAH penetrating into air did not exceed 15%. UV-TiO2 applications ensured high levels of PAH removal in the sludge and also reduced the quantity of PAH penetrating into the air. Within the scope of the samples added with DEA, there was no increase in PAH removal efficiencies and the penetration of PAHs into air was not decreased. In light of these data, it was concluded that UV-TiO2 application is the most suitable PAH removal alternative that restricts the convection of PAH pollution.

  2. The Change of Structural and Thermal Properties of Rocks Exposed to High Temperatures in the Vicinity of Designed Geo-Reactor / Zmiany właściwości strukturalnych i cieplnych skał poddanych wysokim temperaturom w rejonie projektowanego georeaktora

    NASA Astrophysics Data System (ADS)

    Małkowski, Piotr; Niedbalski, Zbigniew; Hydzik-Wiśniewska, Joanna

    2013-06-01

    ści na skutek wysokiej temperatury oraz skonfrontowano powyższe wyniki z wynikami badań przewodności cieplnej, pojemności cieplnej i dyfuzyjności cieplnej (przewodzenia temperatury) skał. Na podstawie opisu mineralogicznego skał przed wygrzaniem stwierdzono, że są to okruchowe skały osadowe z frakcją psamityczną. Szkielet ziarnowy jest zbudowany niemal wyłącznie z ziaren kwarcu, a podrzędnie w skałach występują muskowit, biotyt, skalenie i minerały ciężkie. Zawartość procentowa minerałów i spoiwa zmienia się w szerokim zakresie: ziaren mineralnych od 10,3% do 90,0%, a spoiwa od 10,0% do 89,7%. Po przepaleniu skał do temperatury 1000÷1200°C zmniejsza się w nich zawartość matrix, a wzrasta zawartość kwarcu. Pojawiają się także nowe minerały, takie jak hematyt i minerały rudne. Po ogrzaniu nie stwierdzono cementu węglanowego, opali, tlenowodorków żelaza, kalcytu, hornblendy i porów. Proporcja pomiędzy ziarnami a spoiwem ulega zupełnej zmianie i ziarna stanowią 31-99% objętości, a spoiwo - 1-69%. Wpływ wysokiej temperatury na zmianę struktury i tekstury skał określano obserwując zachowanie się skał w trakcie ich wygrzewania. W pierwszej kolejności zaobserwowano zdecydowanie różny charakter reagowania poszczególnych typów skał na wysoką temperaturę, a w swoich fazach podobny do obserwacji poczynionych przez Mao (Mao et al. 2008). Łupki ilaste wypalały się całkowicie, zmieniały swój kolor na brązowy, a także rozwarstwiały i pękały na drobne kawałki. Łupki piaszczyste generalnie nie zmieniały swojej postaci, lecz często pękały wzdłuż powierzchni uwarstwienia. Laminy materiałów ilastych ulegały przepaleniu i kolor zmieniał się na brązowy lub brunatno-czerwony. Piaskowce całkowicie zachowywały swój kształt, natomiast niektóre minerały zmieniały swój kolor na czerwony lub brązowy. Wykonane badania pokazują, że wszystkie badane skały po wyprażeniu zwiększają swoją gęstość obj

  3. Application of Multidimensional Data Visualization by Means of Self-Organizing Kohonen Maps to Evaluate Classification Possibilities of Various Coal Types / Zastosowanie Wizualizacji Wielowymiarowych Danych Za Pomocą Sieci Kohonena Do Oceny Możliwości Klasyfikacji Różnych Typów Węgla

    NASA Astrophysics Data System (ADS)

    Jamróz, Dariusz; Niedoba, Tomasz

    2015-03-01

    Multidimensional data visualization methods are a modern tool allowing to classify some analysed objects. In the case of grained materials e.g. coal, many characteristics have an influence on the material quality. The paper presents the possibility of applying visualization techniques for coal type identification and determination of significant differences between various types of coal. To achieve this purpose, the method of Kohonen maps was applied by means of which three types of coal - 31, 34.2 and 35 (according to Polish classification of coal types) were investigated. It was stated that the applied methodology allows to identify certain coal types efficiently and can be used as a qualitative criterion for grained materials. Metody wizualizacji wielowymiarowych danych są nowoczesnym narzędziem umożliwającym klasyfikację analizowanych obiektów, którymi mogą być różnego typu dane opisujące wybrane zjawisko lub materiał. W przypadku materiałów uziarnionych, jakim jest np. węgiel, wiele cech ma wpływ na jakość materiału, tj. np. gęstość, wielkość ziaren, ciepło spalania, zawartość popiołu, zawartość siarki itp. Na potrzeby artykułu przeprowadzono rozdział węgli z trzech wybranych kopalni węgla kamiennego, zlokalizowanych w Górnośląskim Okręgu Przemysłowym. Każda z tych kopalni pracuje na innego typu węglu. W tym przypadku były to węgle o typach 31, 34.2 oraz 35 (według polskiej klasyfikacji typów węgla). Najpierw, materiał został podzielony na klasy ziarnowe a następnie za pomocą rozdziale w cieczy ciężkiej (roztwór chlorku cynku) na frakcje gęstościowe. Dla tak przygotowanego materiału przeprowadzono następnie analizy chemiczne mające na celu określenie takich parametrów, jak zawartość siarki, zawartość popiołu, zawartość części lotnych, ciepło spalania oraz wilgotność analityczną. W ten sposób, dla każdej klaso-frakcji uzyskano bogate charakterystyki badanego

  4. Dynamics of Non-Uniformity Loads of Afc Drives

    NASA Astrophysics Data System (ADS)

    Dolipski, Marian; Remiorz, Eryk; Sobota, Piotr

    2014-03-01

    óry tworzą dwa środkowe łańcuchy ogniwowe ze zgrzebłami przymocowanymi do ogniw poziomych łańcuchów. Ze względu na znaczne wydłużenia sprężyste łańcucha zgrzebłowego obciążonego urobkiem węglowym, konieczne jest jego wstępne napinanie. W zależności od wartości napięcia wstępnego łańcucha zgrzebłowego, oporów ruchu w gałęzi górnej i dolnej przenośnika oraz występujących drgań wzdłużnych, łańcuch może się znajdować w jednym z trzech stanów dynamicznych: w stanie stałego luzowania, w stanie okresowego luzowania lub w stanie nieluzowania. W przenośnikach ścianowych obserwuje się nierównomierny rozdział obciążeń na poszczególne napędy. Jego liczbową miarą jest współczynnik rozdziału obciążenia napędu. Jest on definiowany, jako stosunek obciążenia silnika elektrycznego zainstalowanego w danym napędzie do całkowitego obciążenia przenośnika (wzory 1 i 2). W praktyce niemożliwa staje się eliminacja wszystkich przyczyn nierównomiernego obciążenia napędu głównego i pomocniczego w przenośniku ścianowym. Wobec tego podejmuje się działania mające na celu wyrównywanie obciążeń napędów poprzez sterowanie wybranymi parametrami techniczno-ruchowymi przenośnika ścianowego. Badania komputerowe za pomocą własnego modelu dynamicznego wykazały, że jest to możliwe. Tymi parametrami są częstotliwości napięcia zasilania silników asynchronicznych, które powodują zmiany prędkości kątowych bębnów łańcuchowych. W artykule przedstawiono model fizyczny ścianowego przenośnika zgrzebłowego przeznaczony do badania zjawisk dynamicznych wpływających na nierównomierność obciążenia napędów (rys. 1). Opis ruchu w tym modelu fizycznym tworzy układ (4 · j + 5) nieliniowych równań różniczkowych zwyczajnych drugiego rzędu. Dokładając do tego funkcje opisujące współdziałanie bębnów łańcuchowych z łańcuchami oraz funkcje aproksymujące charakterystyki mechaniczne silnik

  5. Geotechnical Aspects of Revitalisation of Post-Mining Areas - An Example of the Adaptation of Katowice Hard Coal Mine for the New Silesian Museum / Geotechniczne aspekty rewitalizacji terenów pogórniczych - przykład adaptacji KWK "KATOWICE" na nowe muzeum śląskie

    NASA Astrophysics Data System (ADS)

    Cała, Marek; Ostręga, Anna

    2013-06-01

    celu: - wzmocnienie posadowienia zabytkowych obiektów i przeniesienie obciążeń na grunt poniżej dna wykopu; - umożliwienie wykonania wewnętrznego poziomu -1 poprzez pogłębienie części budynku maszynowni (MS-8) o jeden poziom; - zabezpieczenie geotechniczne ścian wykopu w rejonie historycznych budynków, - zapewnienie bezpieczeństwa pracy przez okres realizacji podziemnych części Nowego Muzeum Śląskiego jak również funkcjonowania obiektu po zakończeniu procesu rewitalizacji - konstrukcje oporowe przy budynku magazynu odzieży MS-15 i wieży wyciągowej MS-79 będą pełniły rolę docelowych ścian segmentów podziemnych. W artykule zwrócono uwagę na zróżnicowaną budowę geologiczną w rejonie inwestycji, różne obciążenie naziomu, a przede wszystkim na niepewność podłoża i masywu ze względu na wcześniej prowadzone roboty górnicze. Prowadzona przez 176 lat podziemna eksploatacja złóż węgla kamiennego spowodowała osłabienie masywu poprzez m.in. występowanie wkładek węgla kamiennego i stref uskokowych oraz prawdopodobnie starych zrobów. W zależności od rodzaju obiektu będącego przedmiotem zabezpieczenia, jak również konieczności dostosowania technologii zabezpieczenia do zastanych warunków zastosowano kilka rodzajów konstrukcji takich jak palisady czy też bariery mikropalowe stabilizowane kotwiami lub gwoździami. Z uwagi na charakter prac zabezpieczających, dokładność rozpoznania geologiczno-inżynierskiego oraz skalę zadania, projekt zabezpieczeń geotechnicznych miał charakter aktywny. Oznacza to, że rozwiązanie projektowe dostosowywano na bieżąco do faktycznie napotkanych warunków geologicznych. Ponadto podczas realizacji wszystkich prac zabezpieczających wykonywany był monitoring geotechniczny. Ze względu na zabytkowy charakter obiektów sąsiadujących z wykopem konieczny był również monitoring ich konstrukcji. Przedsięwzięcie realizowane jest przy wparciu Europejskiego Funduszu Rozwoju

  6. Unique Project of Single-Cutting Head Longwall Shearer Used for Thin Coal Seams Exploitation / Projekt Jednoorganowego Kombajnu ŚCIANOWEGO O Specjalnej Konstrukcji Przeznaczonego do Eksploatacji POKŁADÓW Cienkich

    NASA Astrophysics Data System (ADS)

    Bołoz, Łukasz

    2013-12-01

    ciany co również korzystnie wpływa na wydobycie. Przekładkę realizować będą, oprócz układów przesuwnych sekcji, układy przesuwne napędów zlokalizowane w chodnikach lub ewentualnie obudowa skrzyżowań. Do sterowania położeniem kombajnu jednoorganowego, a w szczególności kierunkiem eksploatacji na wybiegu ściany (wznios, upad), zastosowane będą siłowniki korekcyjne łączące belkę układu przesuwnego sekcji z rynną przenośnika. Kopalnie jak i producenci sprzętu górniczego wykazują coraz większe zainteresowanie możliwością skutecznej eksploatacji pokładów cienki. Zaproponowany kompleks do eksploatacji cienkich pokładów wyposażony w kombajn jednoorganowy przeznaczony jest do pracy w technologii urabiania dwukierunkowego. Charakterystyczną cechą tej technologii jest brak fazy zawrębiania oraz praca na pełny zabiór na całej długości ściany. W przypadku zmiany grubości pokładu możliwa jest zmiana organu, natomiast sterowanie w kierunku wybiegu odbywać się będzie za pomocą siłowników korekcyjnych. Opracowanie technologii pracy kompleksu wyposażonego w kombajn jednoorganowy, analiza możliwego do osiągnięcia wydobycia dobowego, przy jego zastosowaniu oraz określenie wymaganych parametrów maszyn kompleksu ścianowego, a w szczególności kombajnu, potwierdza poprawność przyjętych założeń.

  7. The Influence of Shale Rock Fracturing Equipment Operation on Atmospheric Air Quality

    NASA Astrophysics Data System (ADS)

    Bogacki, Marek; Macuda, Jan

    2014-12-01

    . Zaadoptowano na potrzeby obliczeń modelowych wskaźniki emisji opracowane między innymi przez Amerykańską Agencję ds. Środowiska, czy Europejską Agencję ds. Środowiska. Obliczenia propagacji w powietrzu zanieczyszczeń pochodzących z analizowanych silników wykonano metodą modelowania matematycznego wykorzystując w tym celu model smugi Gaussa. Wyniki obliczeń pozwoliły na ocenę rozkładu przestrzennego stężeń maksymalnych 1-godzinnych (S1), częstości przekroczeń wartości dopuszczalnej stężeń 1-godzinnych (P(D1)), percentyla 99,8 lub 99,726 ze stężeń 1-godzinnych oraz stężeń średniorocznych (Sa) dla wybranych, najbardziej istotnych z punktu widzenia wpływu na jakość powietrza zanieczyszczeń tj.: NOx (jako NO2), SO2, CO, PM10, benzo(a) pirenu, benzenu, toluenu, ksylenu, formaldehydu, aldehydu octowego oraz akroleiny. Wyniki obliczeń stężeń wybranych substancji w powietrzu na granicy wiertni zestawiono w tabeli 9, natomiast rozkłady przestrzenne stężeń NOx oraz PM10 przedstawiono na rysunkach 3-8. Analiza wyników obliczeń nie wykazała wprawdzie dla analizowanego przypadku występowania przekroczeń obowiązujących w Polsce standardów imisyjnych, ale w przypadku takich zanieczyszczeń jak tlenki azotu (NOx) czy pył PM10 istnieje realne zagrożenie wystąpienia takich przekroczeń, między innymi w sytuacji, gdy łączna moc zainstalowana w silnikach napędzających urządzenia technologiczne w czasie procesu szczelinowania będzie wyraźnie większa niż przyjęta w opisanych badaniach. Wnioski z przeprowadzonych obliczeń wskazują na istotny wpływ na jakość powietrza emisji tlenków azotu (NOx) i pyłu PM10. Ryzyko wystąpienia przekroczeń obowiązujących standardów imisyjnych poza granicą wiertni jest uwarunkowane zarówno czynnikami technologicznymi (łączna moc pracujących silników, parametry spalanego paliwa, zastosowane w silnikach techniki ograniczenia emisji, czas trwania szczelinowania itp.) jak i szeregiem

  8. Interpolation and Sampling Errors of the Ash and Sulphur Contents in Selected Polish Bituminous Coal Deposit (Upper Silesian Coal Basin - USCB) / Błędy Interpolacji I Opróbowania Zawartości Popiołu I Siarki W Wytypowanych Polskich Złożach Węgla Kamiennego (Górnośląskie Zagłębie Węglowe)

    NASA Astrophysics Data System (ADS)

    Mucha, Jacek; Wasilewska-Błaszczyk, Monika

    2015-09-01

    coal seams by means of contour maps is unreasonable if they are based on drill core sampling. Prawo geologiczne i górnicze a w szczególności Rozporządzenie Ministra Środowiska w sprawie dokumentacji geologicznej złoża kopaliny z dnia 22 grudnia 2011 r. nakłada na dokumentatora złoża obowiązek ilustrowania zmienności jakości kopaliny za pomocą map. W odniesieniu do złóż węgla kamiennego rozmieszczenie wartości parametrów charakteryzujących jego jakość najczęściej wizualizuje się za pomocą map izoliniowych zawartości siarki, zawartości popiołu lub wartości opałowej konstruowanych w oparciu o wyniki ich interpolacji w regularnej sieci interpolacyjnej znacznie zagęszczonej w stosunku do sieci rozpoznania złoża. Podstawowymi źródłami informacji o wartościach tych parametrów w warunkach złóż Górnośląskiego Zagłębia Węglowego są wyniki opróbowania rdzeni z otworów wiertniczych (we wczesnych fazach rozpoznania złoża) i wyniki opróbowania bruzdowego pokładów w wyrobiskach górniczych (w zaawansowanych fazach rozpoznania złoża). Otwory wiertnicze są wykonywane w nieregularnej sieci ale z reguły zapewniają jednolite pokrycie złoża. Próby bruzdowe w wyrobiskach górniczych pobierane są na ogół ze stałym rozstawem ale charakteryzują jedynie części złóż rozciętych wyrobiskami. W artykule przestawiono wyniki badań nad wielkością błędów interpolacji zawartości siarki i popiołu oraz na ich tle przedstawiono oszacowania błędów opróbowania wykonane dla dwóch pokładów kopalni Murcki (330 i 334/2) oraz jednego pokładu kopalni Brzeszcze (405/1) (Fig. 1 i 2). Metodyczną podstawę badań stanowiła statystyczna i geostatystyczna analiza zmienności wyników opróbowań, geostatystyczna procedura interpolacji tych parametrów za pomocą zwyczajnego krigingu punktowego oraz dla określenia błędów przygotowania próbki do analizy chemicznej elementy teorii opróbowania Gy (Mucha i Wasilewska, 2006

  9. Application of Relevance Maps in Multidimensional Classification of Coal Types / Zastosowanie Map Odniesienia W Wielowymiarowej Klasyfikacji Typów Węgla

    NASA Astrophysics Data System (ADS)

    Niedoba, Tomasz

    2015-03-01

    potraktowania go jako wielowymiarowego wektora X = [X1,..., Xn]. Zasadniczym problemem jest także wybór jednostki populacji generalnej (ziarno, jednostka objętości lub masy), co może decydować o kierunkach charakteryzowania wielowymiarowych powiązań cech wektora X. Takimi kierunkami charakteryzowania mogą być: - wielowymiarowe rozkłady wektora losowego X wraz ze wszystkimi konsekwencjami metody (Lyman, 1993; Niedoba, 2009; 2011; Olejnik et al., 2010; Niedoba i Surowiak, 2012); - wielowymiarowe równania regresji wraz z analizą macierzy współczynników korelacji liniowej oraz korelacji cząstkowej (Niedoba, 2013b); - analiza czynnikowa (Tumidajski, 1997; Tumidajski and Saramak, 2009); - metody wielowymiarowej wizualizacji danych. W artykule zastosowano nowoczesną metodę wizualizacji wielowymiarowych danych - metodę tzw. map odniesienia (z ang. relevance maps). Aby zastosować ww. metodę przeprowadzono doświadczenia na trzech typach węgla, pobranych z trzech kopalni węgla kamiennego, zlokalizowanych w Górnośląskim Okręgu Przemysłowym. Były to węgle typu 31, 34.2 i 35, według polskiej klasyfikacji węgli. Każdą z pobranych prób poddano rozdziałowi na klasy ziarnowe a następnie każdą z klas ziarnowych rozdzielono na frakcje densymetryczne za pomocą rozdziału w roztworze chlorku cynku. Tak otrzymane klaso-frakcje przebadano chemiczne ze względu na wybrane parametry jakościowe węgla. Były to takie cechy jak: ciepło spalania, zawartość popiołu, zawartość siarki, zawartość substancji lotnych oraz miąższość materiału. Otrzymano w ten sposób zestaw siedmiu danych dla każdej klasy ziarnowej i każdego typu węgla. Stanowił on swoisty siedmiowymiarowy zbiór, który postanowiono zobrazować za pomocą techniki wizualizacji bazującej na tzw. mapach odniesienia. W metodzie map odniesienia na płaszczyźnie służącej do wizualizacji danych zostają rozmieszczone specjalne punkty zwane punktami odniesienia, reprezentujące poszczeg

  10. Laboratory Method for Evaluating the Characteristics of Expansion Rock Bolts Subjected to Axial Tension / Laboratoryjna Metoda Badania Charakterystyk Kotew Rozprężnych Poddanych Rozciąganiu Osiowemu

    NASA Astrophysics Data System (ADS)

    Korzeniowski, Waldemar; Skrzypkowski, Krzysztof; Herezy, Łukasz

    2015-03-01

    statycznym jak i dynamicznym. W podziemnych wyrobiskach górniczych wykonywanych na dużych głębokościach, szczególnie przy eksploatacji złóż rud miedzi w kopalniach LGOM, w których stosuje się samodzielną obudową kotwową istnieje niebezpieczeństwo nieprzewidzianego odpadania bloków skalnych do przestrzeni roboczej. Podstawowym zadaniem kotwienia wyrobisk górniczych jest zapewnienie ich stateczności, jako zasadniczy warunek bezpieczeństwa pracy. Powstają nowe konstrukcje przeznaczone do bardziej ekstremalnych warunków funkcjonowania, w szczególności w warunkach górniczych, ale również w tunelarstwie. Podstawowym rodzajem obudowy wyrobisk przygotowawczych i eksploatacyjnych w podziemnych kopalniach LGOM jest obudowa kotwowa rozprężna lub wklejana. Wybór sposobu utwierdzenia obudowy kotwowej zależy miedzy innymi od: czasu użytkowania, klasy stropu, wymiarów oraz przeznaczenia wyrobiska. W polach eksploatacyjnych, gdzie okres od wykonania wyrobiska do jego likwidacji jest stosunkowo krótki, częściej stosuje się kotwy rozprężne, które ze względu na mniejszą czasochłonność zabudowy, pozwalają na większą wydajność kotwienia. Doceniając rolę i znaczenie obudowy kotwowej oraz jej zużycie sięgające w warunkach polskich milionów sztuk rocznie, w niniejszym artykule opisano nowe stanowisko laboratoryjne umożliwiające badanie rzeczywistej obudowy kotwowej w warunkach obciążeń statycznych. Stanowisko laboratoryjne do badania wytrzymałości na rozciąganie obudowy kotwowej zbudowane w Katedrze Górnictwa Podziemnego AGH umożliwia badania obudów kotwowych przy różnych warunkach obciążeń. Składa się ono z kilku współpracujących ze sobą podzespołów: Hydraulicznego Układu Obciążającego Kotew (HUK), pulpitu sterującego I, pulpitu sterującego II, pulpitu rejestrującego oraz zespołu agregatu hydraulicznego (Rys. 1). W artykule scharakteryzowano zastosowaną aparaturę pomiarową oraz możliwości badawcze

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

    PubMed Central

    Patwardhan, Juilee; Bhatt, Purvi

    2015-01-01

    Flavonoid-enriched fraction can be explored further for topical application to the skin as a ultraviolet-B protectant. Abbreviations used: ABTS: 2,2’-azino-bis-(3-ethylbenzothiazoline- 6-sulphonic acid), AO: Acridine orange, ANOVA: Analysis of variance, ARE: Antioxidant response elements, BSA: Bovine serum albumin, CAPE: Caffeic acid phenethyl ester, CAT: Catalase, DCFH-DA: 2’,7’-dichlorofluorescein diacetate, DMEM: Dulbecco's Modified Eagle's Medium, DMSO: Dimethyl sulfoxide, DNA: Deoxyribonucleic acid, DPBS: Dulbecco's phosphate buffered saline, DPPH: 2,2-diphenyl-1-picrylhydrazyl, ECL: Enhanced chemiluminescence, EDTA: Ethylenediaminetetraacetic acid, ELISA: Enzyme-linked immunesorbent assay, EtBr: Ethidium bromide, FBS: Fetal bovine serum, FE fraction: Flavonoid-enriched fraction, FRAP: Ferric reducing antioxidant power, GPx: Glutathione peroxidase, GR: Glutathione reductase, GST: Glutathione-S-transferase, GSH: Reduced glutathione, GSSG: Oxidized glutathione, HDF: Human dermal fibroblast, HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid, HRP: Horseradish peroxidase, HO-1: Heme oxygenase-1, HPTLC: High-performance thin layer chromatography, Keap-1: Kelch-like ECH-associated protein-1, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, NaCl: Sodium chloride, NFDM: Nonfat dry milk, Nrf2: Nuclear factor E2-related factor 2, NQO1: NAD (P) H: Quinine oxidoreductase 1, OH: Hydroxyl ions, PBST: Phosphate buffered saline with 0.1% tween 20, PCR: Polymerase chain reaction, PMSF: Phenylmethanesulfonyl fluoride, Rf: Retention factor, ROS: Reactive oxygen species, rRNA: Ribosomal ribonucleic acid, SDS: Sodium dodecyl sulfate, SOD: Superoxide dismutase, TLC: Thin layer chromatography, TLC-DPPH: Thin layer chromatography-2,2-diphenyl-1-picrylhydrazyl, UV: Ultraviolet, UV-A: Ultraviolet-A, UV-B: Ultraviolet-B, UV-C: Ultraviolet-C, and qPCR: Quantitative polymerase chain reaction. PMID:26929573

  12. Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling

    NASA Astrophysics Data System (ADS)

    Grace, J. M.; Verseux, C.; Gentry, D.; Moffet, A.; Thayabaran, R.; Wong, N.; Rothschild, L.

    2013-12-01

    bacteria to the presence of a toxic metal, automatically adjusting the level of toxicity based on the number or growth rate of surviving cells. We are on our second prototype iteration, with demonstrated functions of microbial growth monitoring and dynamic exposure to UV-C radiation and temperature. We plan to add functionality for general chemical presence or absence by Nov. 2013. By making the project low-cost and open-source, we hope to encourage others to use it as a basis for future development of a common microbial environmental adaptation testbed. References: Alcantara-Diaz, D. et al. (2004), Divergent adaptation of Escherichia coli to cyclic ultraviolet light exposures, Mutagenesis, 19(5), 349-354, doi:10.1093/mutage/geh039. Goldman, R. P., and Travisano, M. (2011), Experimental evolution of ultraviolet radiation resistance in Escherichia coli, Evolution, 65(12), 3486-3498, doi:10.1111/j.1558-5646.2011.01438.x. Wassmann, M. et al. (2010), Adaptation of Bacillus subtilis cells to Archean-like UV climate: relevant hints of microbial evolution to remarkably increased radiation resistance, Astrobiology, 10(6), 605-615, doi:10.1089/ast.2009.0455. Wielgoss, S. et al. (2013), Mutation rate dynamics in a bacterial population reflect tension between adaptation and genetic load, Proc Natl Acad Sci USA, 110(1), 222-227, doi:10.1073/pnas.1219574110.

  13. Circinaria gyrosa, a new astrobiological model system for studying the effects of heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Martín, María Luisa; Moeller, Ralf; De la Torre Noetzel, Rosa; Raguse, M. Marina

    Up to date, most astrobiological experiments performed on space have been carried out on board of Earth-orbiting spacecrafts (e.g., Foton satellites), or on board of human-tended spacecrafts, (space shuttles and space stations). Organisms included in these experiments have been exposed to harsh space conditions: vacuum, doses of UV and ionizing radiation as well as extreme temperature fluctuations. Space radiation that arrived on these organisms is related with different sources: (e.g. solar particle events, galactic cosmic rays and electromagnetic radiation) [1]. More information on biological effects of cosmic radiation is needed to understand the possible risks for biological systems exposed to space conditions and to broaden our knowledge on the limits of terrestrial life. This study is focused on Circinaria gyrosa (from Aspicilia fruticulosa, ren. see Sohrabi, M., 2012), a vagrant lichen species collected at the steppic highlands of Central Spain. C. gyrosa. has been previously used in various space experiments, e.g., LITHOPANSPERMIA experiment, BIOPAN-6, FOTON M3, 2007, and in ground-based laboratory studies [2]. For example, after intensive UV-C exposure (7.2 x 107J/m2), C. gyrosa showed the highest PS-II activity of all lichens species tested [3]. Based on this high resistance to UV radiation C. gyrosa has been included in the next EXPOSE-R2 ISS experiment called “BIOMEX” (Biology and Mars-Experiment), in which different biological systems will be exposed to space and Martian conditions for nearly one and a half year. Here, we will present our first results of C.gyrosa, which have been obtained in frame of the STARLIFE project, an intercomparison project testing the effects of space-relevant ionizing radiation, i.e., heavy ions and X-rays, on different astrobiological model systems. For C. gyrosa we tested the organism metabolism through pulse amplitude modulated (PAM) fluorescence analysis prior and after the each irradiation experiment. This new data

  14. Performance evaluation of a continuous flow photocatalytic reactor for wastewater treatment.

    PubMed

    Rezaei, Mohammad; Rashidi, Fariborz; Royaee, Sayed Javid; Jafarikojour, Morteza

    2014-11-01

    A novel photocatalytic reactor for wastewater treatment was designed and constructed. The main part of the reactor was an aluminum tube in which 12 stainless steel circular baffles and four quartz tube were placed inside of the reactor like shell and tube heat exchangers. Four UV-C lamps were housed within the space of the quartz tubes. Surface of the baffles was coated with TiO2. A simple method was employed for TiO2 immobilization, while the characterization of the supported photocatalyst was based on the results obtained through performing some common analytical methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), and BET. Phenol was selected as a model pollutant. A solution of a known initial concentration (20, 60, and 100 ppmv) was introduced to the reactor. The reactor also has a recycle flow to make turbulent flow inside of the reactor. The selected recycle flow rate was 7 × 10(-5) m(3).s(-1), while the flow rate of feed was 2.53 × 10(-7), 7.56 × 10(-7), and 1.26 × 10(-6) m(3).s(-1), respectively. To evaluate performance of the reactor, response surface methodology was employed. A four-factor three-level Box-Behnken design was developed to evaluate the reactor performance for degradation of phenol. Effects of phenol inlet concentration (20-100 ppmv), pH (3-9), liquid flow rate (2.53 × 10(-7)-1.26 × 10(-6) m(3).s(-1)), and TiO2 loading (8.8-17.6 g.m(-2)) were analyzed with this method. The adjusted R (2) value (0.9936) was in close agreement with that of corresponding R (2) value (0.9961). The maximum predicted degradation of phenol was 75.50 % at the optimum processing conditions (initial phenol concentration of 20 ppmv, pH ∼ 6.41, and flow rate of 2.53 × 10(-7) m(3).s(-1) and catalyst loading of 17.6 g.m(-2)). Experimental degradation of phenol determined at the optimum conditions was 73.7 %. XRD patterns and SEM images at the optimum conditions revealed that crystal size is approximately 25

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

    PubMed

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

    2004-10-01

    Habitable planets will be subject to intense sources of ionizing radiation and fast particles from a variety of sources--from the host star to distant explosions--on a variety of timescales. Monte Carlo calculations of high-energy irradiation suggest that the surfaces of terrestrial-like planets with thick atmospheres (column densities greater than about 100 g cm(-2)) are well protected from directly incident X-rays and gamma-rays, but we find that sizeable fractions of incident ionizing radiation from astrophysical sources can be redistributed to biologically and chemically important ultraviolet wavelengths, a significant fraction of which can reach the surface. This redistribution is mediated by secondary electrons, resulting from Compton scattering and X-ray photoabsorption, the energies of which are low enough to excite and ionize atmospheric molecules and atoms, resulting in a rich aurora-like spectrum. We calculate the fraction of energy redistributed into biologically and chemically important wavelength regions for spectra characteristic of stellar flares and supernovae using a Monte-Carlo transport code and then estimate the fraction of this energy that is transmitted from the atmospheric altitudes of redistribution to the surface for a few illustrative cases. For atmospheric models corresponding to the Archean Earth, we assume no significant ultraviolet absorbers, only Rayleigh scattering, and find that the fraction of incident ionizing radiation that is received at the surface in the form of redistributed ultraviolet in the biologically relevant 200-320 nm region (UV-C and UV-B bands) can be up to 4%. On the present-day Earth with its ultraviolet ozone shield, this fraction is found to be 0.2%. Both values are many orders of magnitude higher than the fraction of direct ionizing radiation reaching the surface. This result implies that planetary organisms will be subject to mutationally significant, if intermittent, fluences of UV-B and harder radiation

  16. The Modernization of the Energy Sector in Denmark / Modernizacja Sektora Energii W Danii

    NASA Astrophysics Data System (ADS)

    Frączek, Paweł

    2015-03-01

    łego. Kierunek ten jest szczególnie mocno obserwowany w Danii od końca lat 80. XX wieku po publikacji raportu Światowej Komisji ds. Środowiska i Rozwoju (tzw. raportu Brundtlanda). W tym okresie w Danii występowała znacząca emisja zanieczyszczeń atmosfery związana ze zwiększeniem znaczenia węgla kamiennego. Za sprawą rosnącej świadomości społecznej co do konsekwencji środowiskowych gospodarowania energią w latach 90. XX wieku podjęto działania na rzecz ograniczenia zużycia energii. Dla osiągnięcia tego celu istotne było przyjęcie w 1988 r. przepisów zabraniających sto sowania ogrzewania elektrycznego w nowych budynkach, które mają dostęp do sieci ciepłowniczej lub do sieci gazowniczej (Jacobsen, (http)). Przyjęcie tych przepisów przyczyniło się do ograniczenia zużycia węgla będącego w tym okresie głównym źródłem energii elektrycznej i jednocześnie źródłem emisji zanieczyszczeń atmosfery. Wpłynęło to także na zmniejszenie zapotrzebowania na import tego paliwa. Promowanie w tych przepisach rozwoju sieci ciepłowniczych wiązało się ze spalaniem w instalacjach kogeneracyjnych gazu ziemnego, którego zasoby gwarantowały niezależność od importu surowców. Dodatkową korzyścią z wprowadzenia tych przepisów była poprawa bilansu płatniczego kraju oraz zwiększenie zużycia gazu ziemnego. Uświadomienie społeczeństwu konsekwencji ekologicznych realizowanej polityki energetycznej wpłynęło na zwiększenie poparcia dla rozwoju proekologicznych źródeł energii. Społeczeństwo duńskie jest gotowe ponosić większe koszty energii w zamian za gwarancję, że przyczynia się to do ochrony środowiska. Zwiększeniu roli OZE w bilansie energetycznym służy m.in. zrealizowana w 1992 r. reforma podatków dotyczących gospodarowania energią. Reforma ta wprowadziła podatek od paliw konwencjonalnych, przy jednoczesnym zwolnieniu z opodatkowania OZE, co przyczyniło się do ograniczenia zużycia paliw konwencjonalnych. Istot